Search

Despite the fact that it represents only a small part of the total amount of water on the planet (1.2%), land-based water is very significant for man. The demographic explosion that marked the 20th century on the one hand caused constant growth of the need for pure water and on the other hand increased the extent of water pollution due to development of industry, intensification of agriculture and expansion of urban regions. Human action leads to greater or lesser changes of ecological factors in aquatic ecosystems (amount of dissolved oxygen, pH, heavy metal concentration, etc.), regulation of watercourses, disruption of communication between biocoenoses and disturbance of the natural water regime (through the creation of reservoirs). All of this brings about changes in biocoenoses that can be very pronounced, going even so far as to the virtual destruction of life in an aquatic ecosystem or in less severe cases to replacement of an existing biocoenosis by a new one that due to greater homogeneity of ecological factors is characterized by lower diversity. In order to conserve the water resources of the Republic of Serbia, it is necessary to monitor them closely. Biomonitoring is an obligatory part of this task because it is a simple, fast and economical way to follow the state of ecosystems of land-based water. Of all groups of aquatic organisms used in biomonitoring: bacteria, protozoans, zooplankton, phytobenthos, macrophytes and fish, macroinvertebrates are the most widely employed, especially in streams, where they are absolutely the most significant community of bioindicatory organisms. Modern biomonitoring of streams both in the world at large and in Serbia is based to the greatest extent on the use of macroinvertebrates as bioindicators of water quality owing to their many advantages over other aquatic organisms. Macroinvertebrates are widely disseminated organisms that inhabit various types of aquatic ecosystems, from little temporary (ephemeral) stagnant pools, small springs and creeks to large lakes and rivers. The great diversity of macrozoobenthic organisms and extremely complex structure of their communities on the one hand make them very sensitive to anthropogenic action causing changes of ecological factors, and on the other hand enable them potentially to respond with changes in the composition of their biocoenoses that are proportional to intensity of the anthropogenic action in question. Such organisms are characterized by the ability to persist in conditions of fast flowing water because they live attached to the bottom, possess long life cycles and have limited mobility. Their low mobility and sedentary way of life enable the investigator to establish the state of ecological factors on a given area. The relatively long life cycles (lasting 2–3 years) of these organisms make it possible to investigate changes occurring over the course of time. Apart from biological considerations, there are also numerous practical reasons why these organisms are considered good indicators of water quality: samples are taken with relatively inexpensive equipment; the taxonomy of most groups has been thoroughly elaborated; keys for their identification are available; methods that employ macrozoobenthic organisms have been used for many years and are highly reliable; and the responses of certain organisms to different types and levels of pollution have been precisely defined. Мacrozoobenthic organisms can be used to test the influence of anthropogenic stress on aquatic biotopes at all levels of biological organization, from molecular to ecosystematic. The effects of pollution on these organisms under natural conditions are most often analysed on the level of their populations or communities, using structural attributes (measured by indexes of diversity and similarity, biotic indexes, etc.) or functional characteristics, including, for example, primary production, respiratory processes, biomass (secondary production) and circulation of elements, but also aspects of the organisms’ life history such as functional guilds in the feeding of a taxon. Investigation of macrozoobenthic communities has been and will be a central part of the ecology of land-based water, partly due to the fact that streams for them represent a crucial link between resources in the form of organic matter (for example, fallen leaves, algae, detritus, etc.) and fish in food webs, and partly due to the diversity and wide dissemination of the organisms involved. In view of these facts, it is unsurprising that systematic research on the fauna of macroinvertebrates in land-based water of Serbia was initiated almost a century ago and has been carried out in continuity with varying intensity up to the present day. More intensive use of macroinvertebrates in biomonitoring of the ecosystems of land-based water in Serbia, as in the world at large, began around the middle of the last century, at which time they started to be included in monitoring of water quality by the Hydrometeorological Institute of Serbia. As can be seen from the above, Serbian science actively followed world trends in biomonitoring of land-based water from the very start, although the intensity of these investigations was highly variable. Intensification of research on macroinvertebrates and their use in biomonitoring of land-based water occurred during the 1990s, with the formation in Novi Sad, Belgrade and Kragujevac of several independent teams of investigators that laid a solid foundation for further progress, as is evident in a series of studies introducing new and modern methods of biomonitoring, methods such as employment of biomarkers, recording of morphological asymmetries and deformities and use of artificial neuron networks. To be specific, the work of these teams has greatly advanced available knowledge about biology of the macroinvertebrates of land-based water in Serbia and continued to keep pace with world trends in their use for biomonitoring. A good example is the development of BNBI and incorporation of a number of EU standard methods into norms for regulation of biomonitoring in Serbia. Despite this positive trend, it must be stated that the use of macroinvertebrates as bioindicators of the quality of land-based water in Serbia is relatively limited because in the majority of cases it is done within the framework of saprobiological analyses, whereas biotic indexes are for the most part unjustifiably ignored, while multimetric indexes and the multivariant approach have not even begun to be employed. For these reasons, the state of biomomitoring in Serbia still cannot be considered satisfactory. To be specific, if the extent of land-based water biomonitoring in Great Britain where it is continuously conducted at more than 6000 localities is compared with the state of affairs in Serbia where about 90 localities out of a planned 500 are continuously monitored it can be seen that the level of biomonitoring in our country is disproportionally lower. Moreover, a comparison of stream quality in Great Britain, despite that country’s significantly more advanced industrial development and greater population density, with the situation in Serbia shows that the quality of streams in our country is conspicuously far worse. It is clearly necessary to expand the volume and content of biomonitoring because only in that way will it be possible to make correct decisions in the management of water resources and thereby improve their quality. Meanwhile, at the existing level of macroinvertebrate studies in Serbia, that is not simply a question of political willingness, but also a task limited by the quality and quantity of fundamental research. As has been stated before, successful use of macroinvertebrates in biomonitoring demands an exceptionally good knowledge of the base reference state. That at the present time calls for additional faunistic, taxonomic, biogeographic and toxicological research, as well as studies on the typization of watercourses. It will be possible to define groups of reference localities in Serbia, as has been done in Great Britain, only if the inventory of species in our country is known in detail, if taxonomic problems are resolved, if keys for the identification of species are available, if their range has been clarified and if the types of watercourses and their ecological status (condition) are known. This in turn will make it possible to apply some highly organized system of biomonitoring like RIVPACS or to develop a multimetric index like the ones elaborated in the EU’s AQEM program. That the path to this goal is long is clearly indicated by the fact although acknowledged experts today exist for the taxonomy of macroinvertebrate groups such as Chironomidae, Oligochaeta, Heteroptera, Trichoptera, Amphipoda and Gastropoda, research on a number of very important groups such as Ephemeroptera and Plecoptera has only just begun, a situation that has a significant effect on the quality and reliability of determination of these groups, knowledge about their distribution and awareness of their ecological preferences, as well as on the typization of land-based water habitats in Serbia vis-a-vis other countries in the world. Progress in this area largely depends on politics of the state, that is on the measure in which it is ready to support studies, finance the necessary increase in the number of researchers and through selection of programs and projects guide investigative efforts in an appropriate direction. It is also necessary to widen the network of localities at which sampling is prescribed by law, since only by sampling in an organized and planned manner will it be possible to collect an adequate number of data in a procedurally uniform way permitting the drawing of comparisons, development of new biomononitoring methods in Serbia and improvement of ones already in existence. That is the only way to form a standardized database of information about the ecosystems of Serbian streams. Such a database will be the foundation needed for the standardization of reference localities, which represents a key step toward the implementation of both multivariant and multimetric methods in biomonitoring. Да би се водни ресурси Републике Србије очували, неопходно је будно пратити њихово стање. Биомониторинг је неизоставни део овог поступка јер на једноставан, брз, економичан и свеобухватан начин прати стање екосистема копнених вода. Од живог света у копненим водама, макроинвертебрате (голим оком видљиви бескичмењаци) чине једну од најбољих биоиндикаторских група организама за процену стања акватичних екосистема због своје везаности за дно, дугог животног циклуса (2‒3 године) и ограничене могућности кретања. Стога је развијен велики број метода које квантификују биоиндикатор- ска својства ове групе, а све у покушају да се максимализују њихове добре био- индикаторске особине, а минимализују недостаци. Од мноштва метода, у Србији се у стандардном биомониторингу, али и у истраживачком процесу, користе пре свега сапробни индекси, индекси диверзитета и биотички индекси. Иако су ово релевантне мере стања екосистема копнених вода, које се користе и у другим европским земљама, основни недостатак је одсуство регионалности сапробних и биотичких индекса за територију Србије (са изузетком Балканског биотичког индекса), где није извршено прилагођавање индекса са регионалним специфич- ностима насеља акватичних бескичмењака. Други недостатак је потпуно одсуство примене, у стандардном мониторингу, сложенијих и свеобухватнијих метода попут мултиметријских индекса и мултиваријантног приступа који се са великим успехом широко примењују у свету. Разлог за ово може бити и заостатак у познавању фаунистике, таксономије, распрострањења и еколошких преференци организама макроинвертебрата, као и у типизацији станишта копнених вода у Србији, у односу на остале земље у свету. Међутим, у последње три деценије, упркос тешком материјалном стању и недовољној, посебно систематичној бри- зи државе, направљени су значајни помаци радом неколико независних истраживачких група. Те групе су поставиле солидну основу за даљи напредак. који се јасно може и видети кроз низ појединачних истраживања. Ова истраживања уводе нове и савремене методе биомониторинга, попут биомаркера, морфолош- ких асиметрија и деформитета и вештачких неуронских мрежа. Поред улагања у истраживања која су неопходна за стварање услова за систематско увођење нових, осетљивијих и ефикаснијих метода мониторинга, неопходно је и значајно проширити мрежу локалитета који се стандардно узоркују ради биомониторинга у Србији. То је једини начин да се оформи стандардизована база података о екосистемима копнених вода која ће бити неопходна основа за стандардизацију референтних локалитета, што је кључни корак ка имплементацији како мултиваријантних, тако и мултиметријских метода у биомониторингу. Научни скупови / Српска академија наука и уметности ; књ. 171. Одељење хемијских и биолошких наука ; књ. 12

Интеракција флуида и танкозидне структуре коју флуид опструјава или протиче кроз њу је комплексан проблем који се среће у многим инжењерским дисциплинама. Домени две различите области динамике континуума, структуралне механике и динамике флуида, имају заједничку површ раздвајања. Предмет овог рада је интеракција термички оптерећеног канала аеросмеше и струје ваздуха који протиче кроз танкозидну структуру канала затворене контуре, састављену од хомогених, изотропних, челичних плоча. Услед спречених термичких дилатација у средњој површи танкозидног елемента, структура се деформише изазивајући промену облика струјног домена. У новом струјном домену се успоставља струјање другачије од струјања кроз недеформисани канал. Циљ рада је да се оцени утицај деформисане термички оптерећене структуре на струјно поље кроз канал и обратно. Проблем је решен коришћењем нумеричких метода просторне дискретизације континуума. За прорачун напонско-деформационог стања зида канала коришћена је метода коначних елемената. Претпостављена су униформна температурска поља на унутрашњем и спољашњем зиду канала. Дискретизација структуралног домена је извршена коначним елементима љуске формираних на основу Reissner- Mindlin-ове теорије плоча и љуски. Материјал плоче је моделиран серијом билинеарних карактеристика у зависности од температуре, са von Misses-овим условом течења и одговарајућим моделом ојачања материјала. За статичке нелинеарне структуралне прорачуне великих померања и деформација применом Њутн-Рапсонова методе са инкременталним уносом оптерећења коришћени су алгоритми софтверског пакета ANSYS. Дискретизациона метода коначних запремина је коришћена за решавање Рејнолдс усредњених Навије-Стоксових једначина нестишљивог нестационарног струјања ваздуха кроз деформисани канал применом софтверског пакета ANSYS CFX. У циљу оцене дисторзије Апстракт VII мреже коначних запремина у деформисаном струјном простору, деформација мреже је дефинисана фактором крутости који зависи од удаљености од најближег зида. Једначине динамике флуида и структуралне механике су спрегнуте условом да су положај и брзина тачке која лежи на површи раздвајања ова два домена, исте у сваком од домена. У ту сврху је коришћена процедура итеративног узастопног спрезања ова два прорачуна. За пренос оптерећења између различитих домена коришћени су алгоритам претраге по блоковима и метода преноса утицаја интерполацијом са одржањем профила. Резултати прорачуна указују да модел преноса и карактеристике мрежа утичу на конвергенцију и добијени резултат... Fluid - structure interaction is very complex problem that could be faund in many branches of engineering. Structure mechanics and fluid dynamics are interconnecting on the surface of separatin of two different physical domains. The object of this work is interaction of thermally loaded air-coal mixture channel and air flow through the thin walled channel structure of closed conture, made of homogenous, isotropic, steel plates. Thermal load induce deformation of the channel wall into wave - type shapes depending on thermal load and fluid inlet velocity inducing the changes of fluid flow accordingly. The air flow through the new, deformed domain is different than flow through undeformed one. The goal of this work is to evaluate influence of thermally deformed channel on fluid flow and vice versa. The problem is solved using methods of numerical spatial discretization. The finite element method is used for stress-strain calculation. Thermal load is supposed as uniformly distributed temperature fields on inner and outer surface of the channel’s walls. Structure is discretized by shell finite elements based on Reissner-Mindlin formulation. Material model descripte a series of bilinear temperature dependent characteristics, von Misses yield conditions and appropriate flow and hardening rules. The incrementally loaded structural model with geometric and material nonlinearities is solved by Newton-Ralphson method using ANSYS software. The unsteady Navier- Stokes equations are numerically solved using an element-based finite volume method and second order backward Euler discretization scheme. The algorithm of ANSYS CFX software is used for the fluid flow solution. In order to evaluate deformation of flow domain mesh due to deflection of the plates, additional variable, namely mesh stiffnes, is solved. The mesh stiffnes parameterer is related to the distance from the nearest wall, as well as the level of the mesh deformation. The computational structural mechanics and computational fluid dynamics are coupled by the condition that displacement and velocity of the point laying in the interface surface are the same for both domains. The Abstract IX implicit two-way iterative code coupling, partitioned solution approach, were used while solving these numerical tests. The bucket search algorithm and profile preserving interpoaltion method were used for load transfer between disimilar meshes. A set of fluid - structure interaction (FSI) numerical tests have been defined by varying the values of fluid inlet velocity, temperature of inner and outer surface of the channel wall and numerical grid density.The results of this set of numerical calculations indicate that model of load transfer used and meshes charachteristics infuence convergence of the calculation and obtained results...

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju.

Dobro poznavanje kompleksnih ekoloških odnosa u toplovodnim ribnjacima vaţan je preduslov uspešne šaranske proizvodnje u poluintenzivnom sistemu uzgoja. Poslednjih godina dolazi do intenziviranja proizvodnje šarana u Jugoistoĉnoj Evropi (Srbiji, Bosni i Hercegovini, Hrvatskoj, Bugarskoj i Rumuniji) kroz sve širu upotrebu koncentrovane hrane, peletirane i ekstrudirane, umesto ţitarica. Intenziviranje proizvodnje ovih riba nosi sa sobom promene u strukturi i dinamici ribnjaĉkog ekosistema. U periodu od juna do oktobra u devet ribnjaĉkih objekata na ribnjaku ''Kapetanski rit'' na severu Srbije ispitivan je uticaj tri razliĉita tipa dodatne hrane za dvogodišnju šaransku mlaĊ na fiziĉke i hemijske osobine vode, strukturu fitoplanktonske, zooplanktonske i bentosne zajednice ribnjaka i rast šarana. U istraţivanju su korišćena tri tipa dodatne hrane: kombinacija ţitarica u zrnu (kukuruz, pšenica i jeĉam), komercijalna peletirana i komercijalna ekstrudirana hrana sa 25% proteina i 7% masti. Pored toga, analizirana je priroda i jaĉina meĊuzavisnosti razliĉitih komponenata ribnjaĉkog ekosistema primenom analize redundantnosti (RDA). Tip dodatne hrane nije statistiĉki znaĉajno uticao na pokazatelje kvaliteta vode, izuzev na tvrdoću vode, ali je znaĉajno uticao na brojnost cijanobakterija, zooplanktona, bentosnih organizama i rast šaranske mlaĊi. Tako su jezera sa razliĉitim tipom dodatne hrane bila ujednaĉena u pogledu kvalitativnog sastava fitoplanktonske i zooplanktonske zajednice, dok su se znaĉajna odstupanja javila u kvantitativnom sastavu planktona. Cijanobakterije su bile dominantna grupa fitoplanktonskih organizama u svim jezerima, ali je u proseku njihova brojnost bila najmanja u grupi jezera u kojima je riba hranjena peletiranom hranom. TakoĊe, proseĉna brojnost Cladocera i Copepoda je u jezerima sa peletiranom hranom bila znaĉajno veća u odnosu na jezera sa ţitaricama i ekstrudiranom hranom, a brojnost makrozoobentosa je bila veća u odnosu na jezera sa ţitaricama. Rast dvogodišnje šaranske mlaĊi je bio znaĉajno manji u objektima u kojima je korišćena kombinacija ţitarica u odnosu na zimovnike sa dodatkom peletirane i ekstrudirane hrane izmeĊu kojih nije bilo znaĉajnih razlika... Good understanding of complex ecological relationship in carp ponds is an important prerequisite for successful common carp production in semi-intensive system. In recent years it has come to an intensification of carp production in South-East Europe (Serbia, Bosnia and Herzegovina, Croatia, Bulgaria and Romania) through the wider use of industrially compounded feeds, pelleted and extruded, instead cereals. Intensification of production of these fish carries with it changes in the structure and dynamics of the pond ecosystem. The study was conducted from June to October 2009 in nine earthen fishponds at the carp farm ''Kapetanski rit'' in the north of Serbia. The influence of three different supplemental feed types for the two-year carp fry on the physical and chemical properties of water, structure of phytoplankton, zooplankton and benthic pond communities and carp growth was examined. Three types of supplemental feed were used: a combination of cereal grains (corn, wheat and barley), commercial pelleted and commercial extruded feed with 25% of proteins and 7% of fat. In addition using the redundancy analysis (RDA), the nature and strength of the interdependence of various components of pond ecosystems was analysed. The type of supplemental feed did not significantly affect the quality of water, except the hardness of water, but had a significantly effect on the abundance of cyanobacteria, zooplankton, benthic organism and the growth of carp fry. Thus ponds with different type of supplemental feed seemed more uniform in terms of the qualitative composition of the phytoplankton and zooplankton communities, while significant discrepancies occurred in the quantitative composition of these communities. Cyanobacteria were the dominant group of phytoplankton organisms in all ponds, but on average their numbers were the lowest in the group of ponds in which pelleted feed was used. Also, the average number of Cladocera and Copepoda in the ponds with pelleted feed was significantly higher than in ponds in which cereals and extruded feed were used, and abundance of benthic macroinvertebrates was higher than in ponds in which cereals were used...

Угљенични наноматеријали су током последњих неколико деценија постали предмет многобројних истраживања, због својих изузетних структурних, електронских, топлотних, оптичких и хемијских својстава. У тим истраживањима посебан акценат ставља се на проучавање антибактеријских потенцијала различитих хибридних угљеничних наноструктура... Due to its exceptional structural, electronic, thermal, optical and chemical properties, carbon nanomaterials have been the subjects of numerous researches over the last few decades. In these researches, a special emphasis is placed on studying the antibacterial potentials of various hybrid carbon nanostructures. Hybrid nanostructures are, by definition, structures consisting of two materials (components) of which one or both are at the nanometer level and where one material is usually inorganic and the other is organic. Hybrid carbon nanostructures are hybrid structures in which one of the materials is a carbon nanomaterial, such as fullerene, nanotubes, graphene, graphene quantum dots, etc...

U monitoringu površinskih voda neophodno je pored praćenja abiotičkih faktora uključiti i biotičku komponentu tj. analizirati sastav i strukturu zajednica vodenih organizama. Da bi se dobila kompletnija slika o stanju vodenog ekosistema koriste se organizmi bioindikatori. Larva Ephemera danica ima specifične morfološke i funkcionalne karakteristike te je pogodan model organizam za studije biomonitoringa. Cilj doktorske disertacije je praćenje uticaja ispusnih voda pastrmskog ribnjaka na nivo aktivnosti enzima antioksidativne zaštite kod larvi E. danica, ispitivanje stepena bioakumulacije teških metala u telu larvi, vodi i sedimentu reke Skrapež, utvrđivanje faunističkog sastava makrozoobentosa istraživane tekućice. Hidrobiološka istraživanja reke Skrapež sprovedena su tokom 2015. (proleće, leto i jesen) i 2016. godine (zima) na jednom lokalitetu iznad i tri lokaliteta nizvodno od pastrmskog ribnjaka. Dvofaktorska analiza varijanse je pokazala da aktivnost SOD karakteriše veća sezonska varijabilnost, aktivnost GPx karakteriše značajnija longitudinalna varijabilnost i u svim sezonama dolazi do statistički značajnog porasta aktivnosti GPx na drugom lokalitetu, što ukazuje da organsko zagađenje poreklom sa ribnjaka indukuje oksidativni stres kod vrste E. danica. Koncentracija ukupnog glutationa (GSH) dostiže maksimum u jesen na drugom lokalitetu, što je negativan uticaj pastrmskog ribnjaka. Analiza CIA je pokazala postojanje statistički značajne kostrukture između PCA korelacione matrice koncentracija teških metala u sedimentu i u telu E. danica. Indeks saprobnosti ukazuje na uticaj ribnjaka kroz pogoršanje kvaliteta vode nizvodno od njega. Njegov uticaj je i u smanjenju procenta sekača nizvodno od ribnjaka, a povećanju sakupljača, aktivnih i pasivnih sakupljača filtratora. biotic component, i.e., to analyses the composition and structure of communities of aquatic organisms. Bioindicator organisms are used to get a more complete picture of the state of an aquatic ecosystem. The larva of Ephemera danica has specific characteristics that make it a suitable model organism for biomonitoring studies. The purpose of the doctoral dissertation was to monitor the influence of outlet water of a trout farm on the level of activity of antioxidative defense enzymes in larvae of E. danica; test the degree of bioaccumulation of heavy metals in the body of larvae, water, and sediment, and establish faunistic composition of the macrozoobenthos. Hydrobiological investigation of the Skrapež River was conducted during 2015 (spring, summer, and fall) and 2016 (winter) at one locality upstream from the trout farm and three localities downstream from it. Two-factor analysis of variance showed that SOD activity is characterized by high seasonal variability, GPx activity is characterized by considerable longitudinal variability, and a statistically significant increase of GPx activity occurs in all seasons at the second locality, which indicates that organic pollution originating from the fish farm induces oxidative stress in the species E. danica. The concentration of total glutathione (GSH) attains a maximum in the fall at the second locality, which is a negative effect of the trout farm. Use of CIA revealed the existence of a statistically significant contracture between PCA of the correlation matrix of heavy metal concentrations in the sediment and in the body of E. danica. The saprobity index indicates influence of the fish farm in the form of a worsening of water quality downstream from it. Influence of the fish farm manifested in a decrease in the choppers at localities downstream from it, and an increase in the gatherers (active and passive gatherer-filterers).

Predmet istraživanja ove doktorske teze je in vitro određivanje antiradikalske aktivnosti odabranih neurotranmitera, njihovih prekursora i metabolita, a u cilju uspostavljanja odnosa na liniji struktura-antiradikalska aktivnost. Rezultati su upotpunjeni teorijskim proračunima kako bi se dobila potpuna slika parametara važnih za aktivnost prema radikalima od interesa, ali odredili termodinamički i kinetički najpovoljniji mehanizmi. Veliki broj spoljašnjih faktora utiče na povećanje koncentracije slobodnih radikala u organizmu pri čemu nastaje oksidacioni stres. U ovom procesu se ireverzibilno oštećuju biološki značajni molekuli i to dejstvom reaktivnih vrsta kiseonika, azota, hlora i sumpora. U literaturi je pokazano da su slobodni radikali direktno ili indirektno povezani sa razvojem neurodegenerativnih bolesti (Parkinsonove, Alchajmerove, šizofrenije i amiotrofične lateralne skleroze). Aktivnost može biti izražena ili kroz oksidaciju biološki molekula ili formiranje polimernih struktura, odnosno plakova. Većina ispitivanih egzogenih antioksidanasa ne može preći krvno-moždanu barijeru, tako da se ne mogu direktno koristiti za lečenje neurodegenerativnih bolesti. Zbog toga se sve veći značaj pridaje molekulima koji su prisutni u organizmu. Po svojoj strukturi, većina neurotransmitera pripada klasi kateholamina, odnosno poseduju kateholnu grupu koja je i čest strukturni parametar dobrih antioksidanasa. Dopamin, norepinefrin, epinefrin, njihov prekursor L-DOPA i dopaminski metabolit DOPAC poseduju ovu strukturnu jedinicu. Zamenom jedne hidroksilne grupe metoksigrupom nastaju 3-metoksitiramin, homovanilinska kiselina, vanililbademova kiselina (vanillylmandelic acid – VMA), značajni metaboliti neurotransmitera koji se eksperimentalno određuju prilikom dijagnoze bolesti povezanih sa promenom koncentracije dopamina. Tiramin, tirozin i oktopamin imaju hidroksilnu grupu u ppoložaju u odnosu na alifatični niz dok fenilalanin i feniletilamin u strukturi nemaju hidroksilne grupe na aromatičnom prstenu. Tri hidroksilne grupe na aromatičnom prstenu v su prisutne kod 6-hidroksidopamina. Svi ovi molekuli su uključeni u istraživanje kako bi se eksperimentalno i teorijski odredili strukturni parametri, broj i vrsta supstituenata, kao i krajnje grupe alifatičnog niza značajni za antiradikalsku aktivnost. The research topic of this doctoral dissertation is in vitro determination of antiradical activity of selected neurotransmitters, their precursors and metabolites, with the main goal of establishment of the structure-antiradical activity relationship. The results incorporate theoretical calculations in order to obtain a full picture of parameters important for activity towards radicals of interest, but also to determine the thermodynamically and kinetically most favorable mechanism. A large number of external factors influences the increase in the concentration of free radicals which leads to oxidative stress. In this process, the biologically important molecules are irreversibly damaged by the activity of reactive oxygen, nitrogen, chlorine and sulfur species. It is shown in the literature that free radicals are directly or indirectly connected to the development of neurodegenerative diseases (Parkinson, Alzheimer, schizophrenia, amyotrophic lateral sclerosis). The activity of the reactive species is expressed through oxidation of biologically important molecules or the formation of polymeric structures, plaque. The most of investigated exogenous antioxidants cannot cross the blood-brain barrier, therefore they cannot be used for the treatment of neurodegenerative diseases. Because of this, there is an increased interest in the naturally occurring molecules in an organism. Structurally, the majority of neurotransmitters are catecholamines, which means that they possess catechol moiety, the common structural motif of good antioxidants. Dopamine, norepinephrine, epinephrine, their precursor L-DOPA and dopamine metabolite DOPAC have this group. When one of the hydroxyl groups is exchanged with methoxy group the following molecules are obtained: 3-methoxytyramine, homovanillic acid and vanillylmandelic acid. These molecules are experimentally determined in the diagnosis of diseases resulting from a change in the dopamine concentration. Tyramine, tyrosine, and octopamine have one hydroxyl group in p-position with respect to the aliphatic chain. Phenylalanine and phenylethylamine do not possess any hydroxyl groups viii attached to the aromatic ring. There are three hydroxyl groups in the structure of 6- hydroxydopamine. All of these molecules are included in the investigation so experimentally and theoretically important structural parameters like number and type of substituents and end groups of the aliphatic chain are determined.

Biljni ekstrakti koji sadrže derivate kumarina su se često koristili kao biljni lekovi. Iz tih razloga derivati kumarina su intenzivno proučavani i utvrđeno je da ova jedinjenja pokazuju značajne biološke osobine kao što su: antioksidativne, antikoagulacione, antimikrobne, antitumorske itd. S druge strane kompleksna jedinjenja sama ili u kombinaciji sa drugim jedinjenjima, već duži niz godina se koriste u medicini za lečenje brojnih bolesti. Ova jedinjenja imaju primenu u medicini kao antimikrobni agensi, za lečenjenje malignih bolesti, reumatskog artritisa itd. Zbog širokog spektra biološke aktivnosti kako derivata kumarina tako i kompleksnih jedinjenja u okviru ove doktorske disertacije sintetisano je devet novih derivata kumarina i osam odgovarajućih paladijuma(II) kompleksa i ispitivana je njihova in vitro biološka aktivnost. Derivati kumarina su korišćeni kao ligandi u sintezi paladijuma(II) kompleksa. Karakterizacija sintetisanih jedinjenja je izvršena pomoću: rendgenske stukturne analize, spektroskopskih (IR, 1H NMR i 13C NMR) i DFT metoda. Strukturna analiza je pokazala da sva jedinjenja formiraju šestočlani prsten preko intpamolekulske vodonične veze N−H···O, što omogućava da se molekuli javljaju u ketoenolnoj tautomernoj formi. Sva dobijena jedinjenja imaju E geometriju na egzocikličnoj dvostrukoj C3=C1' vezi. Rendgentska strukturna analiza i DFT metoda su potvrdile da su L1–L3 molekuli planarni, dok je za ostale molekule L4–L9 nađeno da kumarinski i anilinski delovi molekula nisu planarni. In vitro antimikrobna aktivnost sintetisanih liganada i odgovarajućih kompleksa paladijuma(II) testirana je mikrodilucionom i disk difuzionom metodom. Mikrodilucionom metodom određene su minimalne inhibitorne (MIC) i minimalne mikrobicidne koncentracije (MMC), dok disk difuzionom metodom je određena zona inhibicije (ZI) ispitivanih jedinjenja. Na osnovu rezultata antimikrobne analize utvrđeno je da jedinjenja L1–L6 i C1–C6 pokazuju slabu do umerene antimikrobnu aktivnost. S druge strane ligandi i kompleksi L7–L9 i C8 i C9 su pokazali veoma dobru antimikrobnu i antifungalnu aktivnost. Herbal extracts, which contains coumarin derivatives, were often used as herbal remedies. For these reasons, the coumarin derivatives have been intensively studied and it has been found that these compounds indicate significant biological properties such as: antioxidant, anticoagulant, antimicrobial, antitumor, etc. On the other hand, complex compounds, alone or in combination with other compounds, have been used for many years in medicine for the treatment of many diseases. These compounds are used in medicine as antimicrobial agents, for the treatment of malignant diseases, rheumatoid arthritis, etc. Because of the wide range of biological activity, both coumarin derivatives and complex compounds, nine new coumarin derivatives and eight corresponding palladium(II) complexes were synthesized. For all of these compounds biological activity was tested in vitro. Coumarin derivatives were used as ligands in the synthesis of the palladium(II) complexes. The characterization of the synthesized compounds was determinate using X-ray structural analysis, spectroscopic (IR, 1H NMR and 13C NMR) and DFT methods. Structural analysis has shown that all compounds form a six-membered ring through the intramolecular hydrogen bond N−H···O, which allows the molecules to appear in the keto-enol tautomeric forms. For all compounds it was found E geometry on the exocyclic double C3 = C1' bond. X-ray structural analysis and DFT method confirmed that L1-L3 molecules are planar, while for other molecules L4-L9 it was found that coumarin and aniline moieties are not planar. In vitro antimicrobial activity of synthesized ligands and corresponding palladium(II) complexes was tested with microdilution and disc diffusion method. The microdilution method has determined the minimum inhibitory (MIC) and minimum microbicidal concentrations (MMC), while the disc diffusion method has determined the inhibition zone (ZI) of the investigated compounds. Based on the results of the antimicrobial analysis, it has been found that the compounds L1-L6 and C1-C6 have shown a low to moderate antimicrobial activity. On the other hand, ligands L7-L9 and complexes C8 and C9 have shown very good antimicrobial and antifungal activity

Aktuelni problem industrije proizvodnje hrane za ribe jeste smanjena dostupnost i visokacena ribljeg brašna, tradicionalnog izvora proteina u hrani za ribe, koja je direktna posledica rasta sektora akvakulture i visoke potražnje za ovim kvalitetnim proteinskim hranivom. Delimična ili potpuna zamena ribljeg brašna visokoproteinskim sirovinama biljnog porekla u recepturama za ishranu riba, uz iznalaženje novih alternativnih visokoproteinskih sirovina pristup je kojim se prevazilazi ovaj problem i koji ima potencijal da obezbedi održivost celokupne industrije hrane za ribe u budućnosti. U okviru ove disertacije predloženo je novo, relativno jednostavno i jeftino tehnološko rešenje za suvo frakcionisanje suncokretove sačme, čijom bi se primenom dobile njene visokoproteinske frakcije kao potencijalne proteinske sirovine biljnog porekla za zamenu ribljeg brašna u hrani za ribe. Shodno tome, istraživanja ove disertacije urađena su u dve odvojene faze, gde je prva, faza vazdušne klasifikacije, imala za cilj ispitivanje mogućnosti primene kombinacije postupaka usitnjavanja suncokretove sačme mlinom čekidarom i vazdušne klasifikacije ovako usitnjene sačme primenom vazdušnog gravitacionog kaskadnog, cik-cak, klasifikatora u cilju dobijanja frakcija povedanog sadržaj proteina u odnosu na polaznu sačmu. Nezavisni parametri usitnjavanja i klasifikacije bili su prečnik otvora sita (POS) čekidara (3, 2 i 1 mm), protokklasifikacionog vazduha (5, 8,7 i 12,5 m3/h) i jačina oscilacije vibro dozatora (JOVD)klasifikatora (30, 60 i 90% maksimuma). Zavisne promenljive bile su sadržaj proteina udobijenim frakcijama i njihov prinos. Primenjen je 3x3x3 potpuni faktorijalni eksperimentalni dizajn prema metodi odzivne površine. U cilju dobijanja frakcije sa štovećim sadržajem proteina, u što većem prinosu, kombinacija postupaka usitnjavanja ivazdušne klasifikacije je optimizovana primenom regresione analize, analize glavnihkomponenata (PCA analiza), analize varijanse, kao i računske dinamike fluida (CFD analiza), kojom je dobijeni kompjuterski model vazdušne klasifikacije suncokretove sačme poređen sa eksperimentalno dobijenim rezultatima. Cik-cak vazdušni klasifikator uspešno je primenjen za razdvajanje usitnjene suncokretove sačme na grubu i finu frakciju. Pri povećanju protoka vazduha smanjivao se prinos grube a istovremeno povećavao prinos fine frakcije. Grube frakcije suncokretove sačme dobijene pri protocima vazduha od 8,7 i 12,5 m3/h imale su za 0,5 − 41,4% relativno veći sadržaj proteina u poređenju sa polaznom sačmom. Smanjenje POS i povećanje protoka vazduha uticalo je na povećanje, dok je povećanje JOVD, uticalo na smanjenje sadržaja proteina grube frakcije. Najveći sadržaj proteina (50,90%SM) imala je gruba frakcija suncokretove sačme dobijena pri sledećim parametrima: POS − 1 mm; protok vazduha − 12,5 m3/h; JOVD − 30%. Na sadržaj proteina grube frakcije i odnos prinosa frakcija značajan uticaj (p < 0,05) imali su POS čekidara i protok vazduha, dok je CFD model pokazao zadovoljavajuće poklapanje sa eksperimentalnim rezultatima. Cilj druge faze disertacije, faze ekstrudiranja, bio je najpre ispitivanje uticaja dodatka polazne suncokretove sačme (oko 37% proteina na SM) i njene dve visokoproteinske frakcije (oko 43% i 49% proteina na SM), dobijenih na osnovu odabranih parametara usitnjavanja i vazdušne klasifikacije, na postupak ekstrudiranja i fizički kvalitet ekstrudirane hrane za ribe. Maksimalno 20% ribljeg brašna bilo je zamenjeno polaznom sunockretovom sačmom i njenim odabranim visokoproteinskim frakcijama, a njihov udeo u recepturi za ishranu pastrmke menjan je na osnovu dizajna smeše. Za ekstrudiranje eksperimentalnih smeša i dobijanje hrane u obliku granula korišćen je dvopužni ekstruder. Ulazni parametri ekstrudiranja bili su konstatni, osim sastava smeše, apraćeni su izlazni parametri ekstrudiranja: temperatura u cevi ekstrudera, temperaturamatrice, pritisak na matrici, specifična potrošnja energije (SME) i obrtni momentelektromotora ekstrudera. Proizvedenim uzorcima ispitani su pokazatelji fizičkog kvaliteta: stepen ekspanzije, nasipna masa, tvrdoća, stepen otiranja, kapacitet upijanja ulja, nivo otpuštanja ulja iz zauljenih granula, stabilnost u vodi i mikrostruktura granula. Prisutvo suncokretove sačme višeg sadržaja proteina i manjeg sadržaja celuloze u smeši uticalo je na formiranje više temperature matrice ekstrudera, kao i na smanjenje SME i obrtnog momenta. Povećanje sadržaja proteina suncokretove sačme doprinelo je stvaranju kompaktnije strukture granule, povećanju tvrdoće, otpornosti otiranju i stabilnosti granula u vodi, smanjenju nivoa otpuštanja ulja, te je tako pozitivno uticalo na fizičke karakteristike granula. Visokoproteinska frakcija suncokretove sačme sa 49% proteina na SM doprinela je optimalnim fzičkim karakteristikama ekstrudirane hrane za pastrmku. Karakterizacija ove frakcije kao potencijalne nove sirovine u industriji hrane za ribe bio je krajnji cilj ispitivanja ove disertacije. U tu svrhu navedena frakcija suncokretove sačme poređena je u novom eksperimentu ekstrudiranja i ispitivanja fizičkog kvaliteta hrane za pastrmku sa ribljim brašnom, kao i sojinim brašnom, koje je najčešće korišćen izvor biljnih proteina u hrani za ribe. Korišćena je nova receptura smeše ali ista postavka eksperimenta kao u prvom delu faze ekstrudiranja. Rezultati su pokazali da je prisustvo visokoproteinske suncokretove sačme sa oko 49% proteina (SM) doprinelo smanjenju temperature matrice, ali i povedanju SME i obrtnog momenta, a time i poroznosti granula što je imalo pozitivan uticaj na kapacitet upijanja ulja granula, stabilnost granula i otpuštanje nutrijenata u vodi, kao i negativan uticaj na stepen otiranja i nasipnu masu granula. Zamena 13,4% ribljeg brašna u recepturi ovom viskoproteinskom frakcijom suncokretove sačme za rezultat je imala granule zadovoljavajućeg fizičkog kvaliteta. Granule najboljeg fizičkog kvaliteta dobijene sukombinacijom visokoproteinske frakcije suncokretove sačme sa sojinim brašnom, te semoglo zaključiti da se funkcionalne karakteristike ove dve sirovine odlično dopunjuju, i da visokoproteinska frakcija suncokretove sačme, sa stanovišta tehnološkog kvaliteta hrane za ribu, predstavlja dobru alternativu ribljem brašnu., High price and finite availability of fish meal (FM), due to high expansion of aquaculturesector in recent decades, are main concerns for modern day aquafeed industry. Partially or completely substation of fish meal in fish feed with protein sources of plant origin, together with finding novel alternative protein sources, is commonly used approach that enables sustainability of aquafeed industry in decades to come. New, relatively simple and low-cost procedure for dry fractionation of sunflower meal (SFM) was proposed within this thesis, with aim for producing high protein SFM fractions as a potential plant source alternative for FM in fish feed. Thus, thesis’s researches were done in two phases, where the aim of the first phase, air classification phase, was to investigate the possibility of applying combination of grinding by hammer mill and air classification of ground SFM using gravitational, cascade air classifier (zigzag), in order to obtain protein enriched fractions. Independent variables of grinding and air classification were sieve openings diameter (SOD) of hammer mill (3, 2 and 1 mm), air flow (5, 8.7 and 12.5 m3/h) and bowl feeder oscillation rate (BFOR) of air classifier (30, 60 and 90% of the maximum). Depended responses were protein content and yield of obtained fractions. The experimental data were obtained using 3 x 3 x 3 full factorial experimental design according to response surface methodology (RSM). For the optimization of grinding and air classification, in order to obtain fraction with highest possible protein content and in high yield, regression analysis, principal component analysis (PCA), analysis of variance (ANOVA) and computational fluid dynamics (CFD) approach were employed. Zigzag air classifier was successfully used for fractionation of ground SFM into coarse and fine fraction. Yield of coarse fractions was decreasing, while fine fractions yield was increasing with the increase of the air flow. Coarse fractions of SFM obtained at 8.7 and 12.5 m3/h were 0.5 − 41.4% relatively enriched in protein content compared to the starting SFM. Decrease of SOD and increase of air flow resulted in coarse fraction protein content increase, while increasing BFOR decreased coarse fraction proteincontent. The coarse SFM fraction with highest protein content was obtained for the SFMground by 1 mm SOD, air flow of 12.5 m3/h, with BFOR set at 30%. Protein content ofcoarse fraction and ratio of fractions yields were significantly affected (p < 0.05) by SOD of hammer mill and air flow. CFD model coincide with the experimental results of airclassification. The first aim of second phase, extrusion phase, was to investigate influence of starting SFM (37% of protein at DM) and its two high protein fractions (43% and 49% of protein at DM), obtained by grinding and air classification, on extrusion process and physical quality of extruded fish feed. Maximum 20% of FM was substituted with SFM and its high protein fractions in trout feed recipe, and their share was changed according to themixture design. Twin screw extruder was used for the production of trout feed samples.Primarily extrusion parameters were constant, except dry mixture composition, andsecondary extrusion factors were observed: extruder barrel’s temperatures, temperatureand pressure at the die, specific mechanical energy (SME) and motor load as torque.Selected physical properties of extruded trout feed samples were determined: radialexpansion, bulk density, hardness, durability, oil absorption capacity, oil leakage, waterstability and microstructure of feed. SFM higher in protein and lower in fiber influencedhigher die temperature and lower SME and torque during extrusion process. Increase inprotein content of SFM resulted in more compact structure of pellets, increased hardness, durability and water stability, decreased oil leakage and thus positively influenced on physical properties of feed. High protein SFM fraction with around 49% of protein (DM) contributed to the optimal physical properties of experimental feed and characterization of this SFM fraction, as a potential new raw material in fish feed industry, was definite aim of this thesis. Towards that, new set of experiments was conducted, where high protein SFM fraction was compared with FM and soybean flour (SBF) by extruding new samples of trout feed and investigating their physical quality. Results of second extrusion experiment showed that presence of high protein SFM fraction (49% of protein DM) in dry mixture decreased die temperature, while increased SME and torque, and with that also increased porosity of pellets, oil absorption capacity and water stability but decreased bulk density and durability. Substitution of 13.4% FM by high protein SFM fraction resulted in pellets with satisfactory physical quality. The highest quality pellets were obtained in combination of high protein SFM and SBF, which lead to the conclusion that functional characteristics of high protein SFM fraction and SBF are complementary, and that novel SFM, from the point of technical quality, presents good FM alternative.

Akvakultura je sektor proizvodnje hrane u svetu sa najbržim rastom. Međutim, uzgoj vodenih životinja je i dalje na daleko nižem stepenu razvoja u odnosu na uzgoj kopnenih životinja. S druge strane, iako je globalni trend proizvodnje u konstantnom rastu, evropska slatkovodna akvakultura beleži stagnaciju u poslednje dve decenije. Radi unapređenja proizvodnje slatkovodnih organizama na starom kontinentu, predožena su dva pravca: pratiti način razvoja gajenja kopnenih životinja i usredsrediti se na mali broj vrsta; ili pratititi princip diverzifikacije, pre svega gajenjem novih vrsta. Kao jedan od glavnih kandidata za diverzifikaciju opisan je smuđ. Gajenje smuđa u intenzivnom sistemu vezano je za recirkulacioni akvakulturni sistem (RAS), koji omogućava visoku kontrolu parametara proizvodnje. Osnovni uslov gajenja nove vrste u RAS-u je upravljanje njenim životnim ciklusom. Stoga, prvi zadatak pri uzgoju smuđa u RAS-u jeste definisanje tehnoloških parametara za stabilnu proizvodnju mlađi pogodne za intenzivan uzgoj. U tom smislu, početne studije su fokusirane na veštački mrest, uzgoj larvi i mlađi. Većina prethodno objavljenih studija o veštačkom mrestu smuđa koristile su divlje matice kao osnovni materijal. Međutim, korišćenje divljih matica ostavlja životni ciklus otvoren. Nadalje, za potrebe uzgoja u intenzivnom sistemu, osnovni preduslov jeste da mlađ konzumira industrijsku koncentrovanu hranu. U slučaju smuđa, opisane su dve tehnologije proizvodnje mlađi naviknute na suvu hranu - proizvodnja mlađi isključivo u RAS-u; i proizvodnja mlađi kombinacijom ekstenzivnog jezerskog sistema i RAS-a. Prethodno objavljene studije o intenzivnom uzgoju larvi smuđa bavile su se optimalnim danom početka tranzicije ishrane larvi sa žive na suvu hranu. Međutim, strategija ishrane, odnosno način prelaska sa žive na suvu hranu nisu bile predmet njihovog istraživanja. Takođe, nekoliko objavljenih studija opisalo je navikavanje jezerski uzgojene mesečne mlađi smuđa na koncentrovanu hranu, međutim, mnoga pitanja sa aspekta tehnologije, ishrane i porekla mlađi neophodna za stabilizaciju ovog proizvodnog procesa ostala su nerešena. U saglasnosti sa opisanim problemima, osnovni cilj istraživanja u okviru ove disertacije je da kroz četiri studije unapredi tehnologiju prozivodnje mlađi smuđa pogodne za intenzivni uzgoj u RAS-u. U prvoj studiji poređen je uspeh veštačkog mresta matica gajenih u RAS-u i divljih matica. Obe grupe prethodno su zimovale u spoljašnjim jezerskim objektima... Aquaculture is the fastest growing food production sector in the world, however, rearing of aquatic animals is still on the far lower developmental stage compared to breeding of terrestrial animals. On the other hand, although on the global level aquaculture production is constantly growing, European freshwater aquaculture is rather stagnant in the last two decades. In order to improve production of freshwater species on the old continent, two directions have been suggested – either to follow developmental pattern of terrestrial animals and focus on the small number of species; or to follow the diversification principle, mainly through breeding of new species. Pikeperch was described as one of the most promising candidates for the task of diversification. Pikeperch intensive rearing is connected to the recirculation aquaculture system (RAS), which allows high control of production parameters. In order to breed the new specie in RAS, management of its life cycle is prime requirement. Therefore, definition of technological parameters for stable production of fingerlings suitable for intensive on-grow is the first task for pikeperch RAS rearing. In that sense, initial studies are focused on artificial reproduction, larvicutlure and juvenile rearing. Most of the previously published studies on the pikeperch artificial reproduction used wild fish as the main material. However, usage of wild broodstock leaves the life cycle opened. Further, fingerling material for intensive rearing must be adapted on the commercial diets. In case of pikeperch, two technologies have been described for production of juveniles habituated to dry feed – juvenile production in RAS exclusively; and juvenile production in combined pond-RAS system. Previously published studies on pikeperch larviculture were dealing with optimal age for weaning. Nevertheless, weaning strategies, i.e. mode of transition from live to inert diets was not the subject of their research. Likewise, several studies described the habituation to dry diets in pond-reared month-old juveniles. However, many issues from aspects of technology, nutrition and juvenile origin remained opened. With regard to described bottlenecks, the main research outcome of this thesis is to improve the production technology of pikeperch juveniles suitable for RAS rearing. Research has been conducted in four studies...

Izvod: Mnoga prirodna polifenolna jedinjenja se smatraju dobrim antioksidantima. Od kada je uočeno da igraju ključnu ulogu u odbrambenom mehanizmu bioloških sistema, njima se pridaje još veći značaj. Iako se u prirodi može naći širok spektar jedinjenja ovog tipa, zbog različitih ljudskih potreba javlja se sve veće interesovanje za specifičnijim antioksidantima fenolnog tipa, zbog čega se na njihovoj sintezi danas intenzivno radi. Međutim, iako se pokazalo da sintetički antioksidanti pokazuju izuzetne osobine i imaju značajnu primenu (npr. u prehrambenoj industriji), mora se voditi računa o njihovom potencijalnom štetnom efektu. U poslednjoj dekadi se značajna pažnja posvećuje rasvetljavanju dualističkog antioksidativno-prooksidativnog ponašanja prirodnih i sintetičkih fenolnih i polifenolnih jedinjenja. Naime, pokazalo se da se pod određenim in vitro uslovima neka fenolna i polifenolna jedinjenja, ponašaju kao dobri antioksidanti, dok se u ćeliji, odnosno normalnom biološkom okruženju, ponašaju na drugačiji način. U ćelijskoj sredini ova jedinjenja, najčešće, ispoljavaju prooksidativno dejstvo, tj. indukuju hiperprodukciju aktivnih kiseoničnih vrsta, pre svega superoksid anjon radikala. U okviru ove disertacije ispitane su antioksidativne i prooksidativne osobine fenolnih jedinjenja. Kako bi se ispitali mehanizmi antiradikalskog delovanja prirodnih jedinjenja fenolnog tipa urađena je analiza galne kiseline kao njihovog predstavnika. Takođe, metodama teorije funkcionala gustine ispitana je antiradikalska aktivnost sintetisanih Šifovih baza. U cilju eksperimentalnog ispitivanja antioksidativne aktivnosti dobijenih fenolnih jedinjenja (Šifovih baza) korišćeni su DPPH test i inhibicija enzima lipoksigenaza, dok je njihova prooksidativna aktivnost testirana in vitro na ćelijskim linijama primarnog kancera debelog creva i sekundarnog kancera dojke, kao i na zdravim ćelijama MRC-5. Summary: Many natural polyphenolic compounds are considered to be good antioxidants. Since it has been noticed that they play an important role in the defense mechanism of biological systems, they are given even greater significance. Although a wide range of compounds of this type can be found in nature, because of different human needs, there is an increasing interest in synthesis of more specific antioxidants of the phenolic type, which is why their synthesis is in focus these days. However, although synthetic antioxidants have been shown to exhibit exceptional traits and have significant application (e.g. in the food industry), their potentially harmful effects must be taken into account. In the last decade, considerable attention was devoted to illumination of dualistic antioxidative-proxidative behavior of natural and synthetic phenolic and polyphenolic compounds. Namely, certain in vitro conditions have shown that some phenolic and polyphenolic compounds behave as good antioxidants, whereas they behave in a different way in a cell or a natural biological environment. Most frequently, in the cellular environment these compounds exhibit a prooxidative effect, i.e. induce hyperproduction of active oxygen species, primarily superoxide anion radicals. Within this dissertation the antioxidative and protoxidative properties of phenolic compounds were examined. In order to investigate mechanisms of antiradical action of natural compounds of the phenolic type, analysis of gallic acid as their representative was performed. Also, the methods of density functional theory (DFT) were applied for the investigation of the antiradical activity of the synthesized Schiff bases. For the purpose of experimental testing of the antioxidant activity of the obtained phenolic compounds (Schiff bases), DPPH and lipoxygenase enzyme inhibition were used, while their prooxidative activity was tested in vitro on the cell lines of the primary colon cancer and secondary breast cancer, as well as on healthy MRC-5 cells . The obtained results are of scientific importance because they contribute to the clarification of the antioxidative and/or antiradical behavior of phenolic compounds and their in vitro tested prooxidative or cytotoxic action.

Planinske tekućice čine bitnu komponentu rečne mreže i prilično specifične delove toka, koje zbog svoje teške pristupačnosti uglavnom predstavljaju najmanje remećene delove vodotoka. Međutim, različite ljudske aktivnosti, kao što su: vodosnabdevanje, izgradnja kanala, poljoprivreda, itd., remete njihovu homeostazu. Jedan od takvih oblika uticaja na ove osetljive akvatične ekosisteme može se prepisati i pastrmskoj akvakulturi. Uzimajući u obzir da pastrmski ribnjaci vrše direktan uticaj na brdsko-planinske tekućice, njihovi efekti mogu biti slični mnogim drugim zagađivačima koji organske materije i različite tipove polutanata direktno oslobađaju u recipijente. Pored hemijskog monitoringa koji može ukazati na nastale promene u koncentracijama abiotičkih parametara u vodi i supstratu, korišćenjem organizama sa indikatorskim svojstvima dobija se kompletnija slika o promenama nastalim u vodenom ekosistemu. Od svih grupa vodenih organizma, u biomonitoringu tekućih vodenih ekosistema, najčešće se koriste organizmi makrozoobentosa, jer se njihovom primenom mogu pratiti promene na svim nivoima biološke organizacije, od molekularnog do ekosistemskog. Za ispitivanje uticaja pastrmskih ribnjaka na zajednice makrozoobentosa, u ovoj disertaciji uključeno je devet tekućica lociranih u brdsko-planinskim područjima Srbije, u okviru pete i sedme limnofaunističke zone slatkovodne faune Evrope. Uzorkovanje je vršeno na ukupno 50 lokaliteta, sedam puta u toku jednogodišnjeg istraživanja. Izbor pastrmskih ribnjaka izvršen je na osnovu njihove produkcije i u odnosu na veličinu recipijenta. Intenzitet uticaja pastrmskih ribnjaka ispitan je preko abiotičke i biotičke komponente vodenog ekosistema. Kvalitativnom analizom i analizom glavnih komponenti između kontrolnog lokaliteta i lokaliteta neposredno ispod ribnjaka ustanovljene su promena sledećih abiotičkih parametara: nagomilavanje mulja u podlozi, porast koncentracije jonizovanog amonijaka i njegove nejonizovane frakcije, pad koncentracije rastvorenog kiseonika, porast vrednosti pH, kao i blagi porast koncentracije ortofofata i ukupnog fosfora... Mountain streams are an important component of the river network that due to their heavy accessibility are generally the least disturbed parts of a watercourse. However, their homeostasis is upset by various human activities such as diversion for water supply purposes, canal building, irrigation, etc. Trout aquaculture can be cited as one form of such influence on these sensitive aquatic ecosystems. Trout farms exert direct influence on highland streams and their effects resemble those of many other polluters that release organic substances and various types of pollutants directly into the recipient waters. A more complete picture of changes arising in an aquatic ecosystem can be obtained by using organisms with indicatory properties in conjunction with chemical monitoring, which clearly indicates changes in the values of abiotic parameters. Of all groups of aquatic organisms, macrozoobenthic organisms are most often used in biomonitoring of the ecosystems of streams because it is possible with them to follow changes on all levels of biological organization, from the molecular level to that of the ecosystem as a whole. In order to investigate the influence of trout farms on macrozoobenthos communities, in this dissertation nine streams were monitored in highland regions of Serbia within the fifth and seventh limnofaunistic zones of the freshwater fauna of Europe. Sampling was conducted at a total of 50 localities over the course of a one-year period. The choice of trout farms was based on the volume of their production and size of the recipient stream. The intensity of influence of trout farms was investigated by monitoring abiotic and biotic components of the aquatic ecosystem. Qualitative analysis and principal component analysis of the difference between the control locality and localities directly below the trout farm revealed the following changes of several abiotic parameters, viz., accumulation of sludge in the substrate, increase in the concentration of ionized ammonia and its nonionized fraction, decrease in the concentration of dissolved oxygen, increase of pH, and slight increase in the concentration of orthophosphate and total phosphorus...

После кратког уводног прегледа, рад је подељен на два дела. Први део се бави присуством вероватноће у логици (в. [16], [17], [18], [19], [22], [23] и [24]), а други је посвећен примени ентропије у класификацији поливалентних логика (в. [14], [15], [20], [21] и [25]). Основна идеја која доминира првим делом рада јесте обогаћивање Gentzen- овог рачуна секвената класичне логике исказа једним вероватносним оператором дефинисаним над секвентима Γ ⊢ Δ како би се изразила чињеница да "вероватноћа истинитости секвента Γ ⊢ Δ припада интервалу [а, б] ⊂ [0, 1]". Уводимо следеће системе: LKprob, LKprob(ε), NKprob i LKfuzz. Основна форма секевната у систему LKprob је Γ ⊢ b, a Δ са горе датим значењем. Систем LKprob(ε) се фокусира на Suppes-ове форме Γ ⊢ n Δ које омогућавају формализацију реченице "вероватноћа истинитости секвента Γ ⊢ Δ припада интервалу [1 - nε,1] ⊆ [0, 1]", за неки n ∈ N. Систем NKprob представља природно-дедукцијски аналогон рачуну секвената LKprob. Модели засновани на Carnap–Popper–Leblance-овој семантици дефинисани су за сваки од ових рачуна уз одговарајуће резултате сагласности и потпуности. Коначно, рачун LKfuzz је уведен са опџтијом формом секвената Γ ⊢ х Δ, где је х елемент коначне мреже, са циљем да се опише једно расплинуће рачуна LK. Значење секвента Γ ⊢ х Δ је "да је х мера расплинућа секвента Γ ⊢ Δ". Модели за LKfuzz су дати са резултатима сагласности и потпуности, а доказ-теоретски третман рачуна LKfuzz укључује и теорему елиминације сечења. Други део рада истражује чињеницу да сваки логички систем повезан са партицијом индукованом одговарајућом Lindenbaum–Tarski–јевом алгебром омогућава дефинисање његове ентропије. Дефинишемо ентропију логичког система базираној на геометријској расподели мера над одговарајућом партицијом скупа формула. Ова дефиниција омогућава класификацију поливалентних исказних логика у односу на њихову ентропију. Асимптотске апроксимације ентропије неких бесконачновалентних логика су такође дате. Размотрени примери укључују Lukasiewicz-еву, Kleene-јеву и Priest-ову тровалентну логику, Belnap-ову четворовалентну логику, Gödel-ове и McKay-еве m-валентне логике, и Heyting-ову и Dummett-ову бесконачновалентну логику. After a brief introductory survey, this work is divided into two parts. The first part deals with presence of probability in logic (v. [16], [17], [18], [19], [22], [23] and [24]), and the second one is devoted to the application of entropy in classification of many–valued logics (v. [14], [15], [20], [21] and [25]). The basic idea, dominant in the first part of the work, is to enrich the Gentzen’s sequent calculus LK for propositional classical logic by a kind of probability operator defined over the sequents Γ ⊢ Δ in order to express the fact that ”the truthfulness probability of Γ ⊢ Δ belongs to the interval [a, b] ⊂ [0, 1]”. We introduce the following four systems: LKprob, LKprob(ε), NKprob and LKfuzz. The basic form of sequents in LKprob is Γ ⊢ b, a Δ with the above given intended meaning. The system LKprob(ε) is focused on the Suppes-forms Γ ⊢ n Δ enabling to formalize the sentence ”the truthfulness probability of Γ ⊢ Δ belongs to the interval [1 - nε,1] ⊆ [0, 1]”, for some n ∈ N. The system NKprob presents a natural deduction counterpart of the sequent calculus LKprob. The models founded on Carnap– Popper–Leblance probability semantics are defined for each of these calculi and accompanied by the corresponding soundness and completeness results. Finally, the calculus LKfuzz is introduced with a more general form of the sequents Γ ⊢ х Δ, where x is an element of a finite lattice, with the aim to describe a fuzzification of LK. The meaning of Γ ⊢ х Δ is that ”x is the fuzziness measure of Γ ⊢ Δ". Models for LKfuzz are given with soundness and completeness results, and a proof– theoretical treatment of LKfuzz includes the cut–elimination theorem. The second part of the work explores the fact that each logical system associated with the partition induced by the corresponding Lindenbaum–Tarski algebra makes it possible to define its entropy. We define the entropy of a logical system based on geometric distribution of measures over matching partition of set of formulae. This definition enables the classification of many–valued propositional logics according to their entropies. Asymptotic entropy approximations for some infinite–valued logics are proposed as well. The considered examples include Lukasiewicz’s, Kleene’s and Priest’s three–valued logics, Belnap’s four–valued logic, Gödel’s and McKay’s m– valued logics, and Heyting’s and Dummett’s infinite–valued logics.

Mehanizam karboksilacije fenoksida različitih metala bio je tema brojnih eksperimentalnih i teorijskih istraživanja. Mada postoje brojni eksperimentalni rezulati o Kolbe-Šmitovoj reakciji naftoksida alkalnih i zemnoalkalnih metala, mehanizam obrazovanja hidroksinaftoevih kiselina do sada nije ispitivan teorijskim metodama. U okviru ove doktorske disertacije ispitan je mehanizam karboksilacije naftoksida natrijuma, kalijuma, rubidijuma i cezijuma u položajima 1 i 3. U slučaju natrijum 2-naftoksida (NaphO-Na) ispitan je i mehanizam reakcije u položaju 6. Ispitivanje mehanizma karboksilacije izvedeno je u korelaciji sa ispitivanjem strukturnih i elektronskih osobina učesnika u reakciji. Rezultati ove doktorske disertacije dobijeni su pomoću metoda funkcionala gustine koje su implementirane u programski paket Gaussian: B3LYP, B3LYP-D2 i M06- 2X u kombinaciji sa bazisnim skupovima LANL2DZ, 6-311+G(d,p) za ugljenik, kiseonik i vodonik i Def2-TZVPD za metal. Metode B3LYP-D2 i M06-2X dizajnirane su za modeliranje nekovalentnih interakcija, te su korišćene da bi se što bolje opisali disperzioni efekti na kratkim i srednjim međuatomskim rastojanjima (≤ 500 pm). Proračuni su izvedeni za gasovitu fazu. Urađena je NBO (Natural Bond Orbital) analiza većine optimizovanih geometrija radi utvrđivanja efekata koji proističu iz elektronske strukture. Istraživanje mehanizma Kolbe-Šmitove reakcije naftoksida alkalnih metala (NaphO-M) pomoću funkcionala B3LYP pokazalo je da, kao i u slučaju fenoksida alkalnih metala, reakcija započinje građenjem stabilnog intermedijernog kompleksa V- M. Što se tiče reakcionih puteva u položajima 1 i 3, ugljenik iz SO2 vrši elektrofilni napad na S1 prstena, što vodi do nastanka metalnog 2-hidroksi-1- naftoata (E1-M). Iznenađujuće je da prelazno stanje za elektrofilni napad na S3 naftalenskog prstena nije pronađeno. Građenje 3-hidroksi-2-naftoata (E3-M) objašnjeno je 1,3-premeštanjem SO2M grupe. Treba istaći da prelazna stanja za 1,3-premeštanje kod reakcija NaphO-Rb i NaphO-Cs nisu pronađena. Reakcija u položaju 6 ispitana je samo za NaphO-Na. Ni ovde nije nađeno prelazno stanje za elektrofilni napad na S6 naftalenskog prstena. Nađeno je da reakcioni put 6 8 započinje elektrofilnim napadom na S8, što posle uzastopnih premeštanja CO2Na grupe vodi do građenja intermedijera D6-Na. Dalje se događa homolitičko raskidanje veze C6-H pri čemu nastaje radikal koji vezivanjem za atom vodonika gradi sporedni proizvod reakcije natrijum 6-hidroksi-2-naftoat (E6-Na). Rezultati dobijeni pomoću funkcionala M06-2X i B3LYP-D2 su međusobno u dobroj meri konzistentni, a dosta se razlikuju od rezultata dobijenim pomoću metode B3LYP. NaphO-Na i SO2 mogu da nagrade dva kompleksa: V-Na (već opisan) i S-Na. Dok V-Na ne može da se dalje transformiše do reakcionih proizvoda, SO2 grupa u S-Na zauzima idealan položaj za elektrofilni napad u sva tri položaja: 1, 3 i 6. Svaki reakcioni put se odigrava preko odgovarajućeg prelaznog stanja u kom se gradi nova S-S veza, i intermedijera D-Na. U sledećem, bimolekulskom reakcionom koraku, dva intermedijera D-Na razmenjuju protone susedne SO2 grupama. Ovi intermolekulski reakcioni koraci zahtevaju značajno manje energije aktivacije u poređenju sa intramolkulskim prelazom protona sa ugljenika na kiseonik. Bez obzira na primenjenu metodu mogu se izvesti sledeći zaključci: U poređenju sa reakcijama karboksilovanja naftoksida u položajima 1 i 3, reakcioni put u položaju 6 je i kinetički i termodinamički daleko nepovoljniji. Putevi 1 i 3 su kompetitivni, pri čemu put 1 zahteva niže energije aktivacije ali put 3 vodi do stabilnijeg proizvoda. Ovaj zaključak je u saglasnosti sa eksperimentalnim rezultatima koji su pokazali da na dosta niskoj temperaturi od 20oS nastaje samo E1-M, dok sa povećanjem temperature raste prinos proizvoda E3-M i E6-M. Pošto se Kolbe-Šmitova reakcija izvodi na visokim temperaturama glavni poizvod reakcije je termodinamički najstabilniji E3-M. The mechanism of the carboxylation reaction of different metal phenoxides has been a subject of numerous experimental and theoretical investigations. In spite of the fact that there are many experimental results on the Kolbe-Schmitt reaction of alkali and alkaline earth metal naphthoxides, the mechanism of formation of hydroxy naphthoic acids has not been investigated by means of theoretical methods. Within this doctoral dissertation the mechanism of the carboxylation reaction in the positions 1 and 3 was examined for the naphthoxides of sodium, potassium, rubidium, and cesium. In the case of sodium 2-naphthoxide (NaphO-Na) the mechanism in the position 6 was also examined. The examination of the carboxylation reaction mechanism was carried out in correlation with the investigation of structural and electronic properties of the participants in the reaction. The results of this doctoral dissertation were obtained by means of the density functional methods which are implemented in the Gaussian program package: B3LYP, B3LYP-D2, and М06-2X. These methods were applied in combination with the following basis sets: LANL2DZ, 6-311+G(d,p) for carbon, oxygen, and hydrogen, and Def2-TZVPD for metals. The B3LYP-D2 and М06-2X methods have been designed for modeling noncovalent interactions, and thus, they were used to describe dispersion effects at short and medium interatomic distances (≤ 500 pm). The calculations were performed for the gas-phase. The NBO (Natural Bond Orbital) analysis was performed for majority of the optimized geometries for explanation of the effects which result from the electronic structure. The investigation of the mechanism of the Kolbe-Schmitt reaction of the alkali metal naphthoxides (NaphO-М) was carried out by using the B3LYP functional. Similarly to the case of the alkali metal phenoxides, it was shown that the reaction begins with the formation of a stable intermediate complex В-М. As for the reaction pathways 1 and 3, the carbon from СО2 performs an electrophilic attack on C1 of the ring, which leads to the formation of the metal 2- hydroxy-1-naphthoate (Е1-М). It is surprising that a transition state for an electrophilic attack on C3 of the naphthalene ring was not revealed. The formation of 3-hydroxy-2-naphthoate (Е3-М) was explained with a 1,3-shift of the СО2М group. It should be pointed out that transition states for the 1,3-shift in the reactions of NaphO-Rb и NaphO-Cs were not revealed. 10 The reaction in the position 6 was examined only in the case of NaphO-Na. Again, a transition state for an electrophilic attack on C6 of the naphthalene ring was not revealed. It was found that reaction pathway 6 begins with an electrophilic attack on C8 followed with few consecutive rearrangements of the CO2Na group, and yields the D6-Na intermediate. Further, a homolytic cleavage of the C6-H bond takes place, and a radical is built. This radical reacts with a hydrogen atom, and in this way the minor reaction product sodium 6-hydroxy-2-naphthoate (E6- Na) is built. The results obtained by using the М06-2X and B3LYP-D2 functionals are mutually consistent to a great extent. At the same time, they are significantly different from those obtained with the B3LYP method. NаphO-Na and СО2 can build two complexes: В-Na (already described) and С-Na. While В-Na cannot transform to yield the reaction products, the СО2 group in С-Na takes an ideal position for аn electrophilic attack in all three positions: 1, 3 and 6. Each reaction pathway occurs via a corresponding transition state where a new С-С bond is being formed, and the intermediates D-Na. In the next, bimolecular reaction step, two D-Na intermediates exchange the protons adjacent to the СО2 groups. These intermolecular reaction steps require significantly lower activation energies in comparison to intramolecular proton transfer from the carbon to the oxygen. Independently of the applied method, the following conclusions can be made: In comparison to the carboxylation reactions of naphthoxides in the positions 1 and 3, reaction pathway in the position 6 is both kinetically and thermodynamically unfavorable. Pathways 1 and 3 are competitive, where pathway 1 requires lower activation energies, but pathway 3 leads to the more stable product. This conclusion is in agreement with the experimental results which showed that at rather low temperature of 20оС only Е1-М is formed, whereas the yields of the products Е3-М and Е6-М increase with the increasing temperature. Since the Kolbe-Schmitt reaction is performed at high temperatures the major reaction product is thermodynamically most stable E3-М.

Овај рад представља истраживање утицаја античке грчке математике на Платонову филозофију; анализује се питање да ли је и ако јесте, на који начин је математика Платоновог времена произвела неке од Платонових филозофских позиција, превасходно када се ради о тзв. неписаном учењу и космологији дијалога Тимај. Такође, истражује се утицај математике на Платонову артикулацију метода истраживања из хипотеза у дијалозима средњег периода Менон и Федон. У истраживању се комбинују херменеутички метод са методом компаративне анализе, уз унакрсно истраживање Платонове филозофије и значајнијих ставова античке грчке математике. Главни приступ је проблемски. Испитују се Платонови списи, уз неопходно консултовање Аристотелових сведочанстава и сведочанстава античких доксографа, посебно Проколових Коментара на прву књигу Еуклидових Елемената. Референтни математички спис су сами Еуклидови Елементи. Неки од главних резултата до којих је ово истраживање дошло су: 1) Платонов метод истраживања из хипотеза настао је као резултат потребе установљавања филозофије као „строге науке”, по узору на математику; 2) идеје-бројеви и идеалне димензије имају онтолошки статус идеја а не математичких ентитета, иако су ови појмови настали под утицајем античке математичке теорије о броју и димензијама; 3) упркос томе што Платонова позна космологија инкорпорише релевантна математичка учења његовог времена, посебно астрономска, она није математичка; математика није овом мислиоцу послужила као модел за космологију него Платонов космолошки дискурс, уз присуство научних елемената, остаје телеолошко- митолошки; 4) с обзиром да идеје-бројеви и идеје димензија нису математички ентитети, не може се казати ни да је математика Платону била модел за онтологију. Платонова онтологија до краја је остала филозофска – упркос снажном утицају математике на неписано учење и космологију Тимаја, она никада није постала математичка This research focuses on the influence of ancient Greek mathematics on Plato's philosophy...

Poznavanje distribucije vrsta kao i uspešnost predviđanja njihovog prisustva, od posebnog je značaja za upravljanje akvatičnim biodiverzitetom i procenu intenziteta antropogenog uticaja na vodene ekosisteme. Poslednjih decenija, potreba za restauracijom i očuvanjem akvatičnih ekositema, dovela je do razvoja efikasnih ekoloških pristupa, baziranih na biološkim podacima, za procenu ekološkog statusa u mnogim zemljama sveta. Prema Evropskoj Okvirnoj Direktivi o Vodama (WFD) fauna riba se smatra neizostavnom grupom akvatičnih organizama u proceni ekološkog statusa tekućih voda. Zbog toga, biotički indeksi zasnovani na zajednici riba bivaju u sve češćoj primeni u proceni i monitoringu ekološkog statusa akvatičnih ekosistema. Ciljevi ovog istraživanja bili su: analiza prostorne dinamike zajednice riba, procena značaja sredinskih faktora u strukturiranju zajednice i testiranje ekološke relevantnosti a priori klacifikacije staništa pomoću sredinskih varijabli korišćenjem ihtiofaune kao biotičke komponente. Konačno, kao poseban cilj ističe se definisanje vrsta indikatora kvaliteta vode i staništa, kao i formulacija novog pristupa za procenu kvaliteta i ekološkog statusa tekućih voda, korišćenjem riba kao bioindikatora, koji odražava regionalne specifičnosti Srbije. Uzorci su sakupljeni u periodu od 2003. do 2011. godine, na 124 lokaliteta raspoređenih duž slivova Velike Morave i Drine (Crnomorski sliv), i 7 lokaliteta na rekama koje pripadaju Egejskom slivu. Za grupisanje uzoraka korišćena je metoda Veštačkih neuro mreža, Kohoneove samoorganizujuće mape (eng. self-organizing map (SOM)), koja se, prema dosadašnjim studijama, pokazala veoma pouzdanom za primenu u ekološkim studijama. Za definisanje prostorne organizacije ribljih zajednica posmatrani su lokaliteti sa slivnog područja Velike Morave. Tom prilikom, SOM analiza je, na osnovu biomase ribljih vrsta, ukazala na prisustvo dve grupe uzoraka, X i Y. Grupa Y se sastoji od lokaliteta smeštenih na donjim tokovima reka, dok je grupa X dalje podeljena na podgrupe X1 (srednji tokovi reka) i X2 (gornji tokovi reka). Rezultati su pokazali da klasifikacija ribljih zajednica u velikom stepenu odgovara a priori klasifikaciji na osnovu sredinskih promenljivih. Pojedina odstupanja posledica su intenzivnog delovanja antropogenog faktora. Klasifikaciona snaga (CS) ima veće vrednosti kada se radi o grupama lokaliteta podeljenih na osnovu SOM analize u odnosu na a priori definisane grupe. Sredinski parametri, nadmorska visina i dominantni supstrat, pokazali su se kao faktori od posebnog značaja za strukturiranje zajednice. Takođe, SOM analiza je u ovom radu primenjena je i sa ciljem grupisanja lokaliteta u karakteristične ekološke entitete, tipove reka, u zavisnosti od tipa staništa. Dobijeni tipovi reka su tokom dalje obrade podataka, uz pomoć k- means klaster analize, grupisani u četiri grupe, pri čemu svaka grupa odovara određenom ekološkom stanju. Indikatorske vrste su definisane za svaku grupu na osnovu njihove konstantnosti i dominantnosti. Gradijent na SOM mreži je praćen za jedanaest metričkih osobina. Od ukunog broja posmatranih metričkih osobina, pokazalo se da devet pokazuje jasan gradijent na SOM mapi, dok su Kruskall–Wallis ANOVA i Mann–Whitney test ukazali da se samo tri metričke osobine statistički značajno razlikuju između svih grupa. Rezultati ovog istraživanja prikazuju prostornu organizaciju ribljih zajednica što značajno može doprineti njihovoj implementaciji u programe bioprocene. Na osnovu odabranih metričkih osobina i indikatorskih vrsta, dat je model, zasnovan na zajednici riba, za procenu ekološkog statusa tekućih voda Srbije (fBNBI). Značaj ovog rada leži u činjenici da je fBNBI prvi pokušaj prilagođavanja IBI-a (Indeksa Biotičkog Integriteta) regionalnoim specifičnostima Srbije, koji bi omogućio procenu ekološkog statusa tekućih voda Srbije i detekciju vodotokova koji zahtevaju zaštitu i restauraciju. Konačno, kako bi se postigla pouzdana i sveobuhvatna procena ekološkog stanja, BNBI i fBNBI bi trebalo primenjivati istovremeno. Knowledge of a species’ distribution and the capacity to predict its occurrence are considered essential for managing aquatic biodiversity and assessing the anthropogenic alterations in river environments. In the last decades, the necessity of the restoration and maintenance of healthy aquatic ecosystems has led to the development of practical and effective ecological tools based on biological data in many countries. According to the European Water Framework Directive (WFD), fish fauna is considered as a mandatory group of aquatic biota in the evaluation of the ecological status of running waters. Therefore, fish biotic indices have become common tools for measuring and monitoring the ecological status of aquatic ecosystems. The aim of the study was to analyze spatial variation in the fish assemblages, to investigate the importance in environmental factors in structuring the community and to test the ecological relevance of the a priori landscape classification using fish as biological data. Finally, our specific goal was to define indicator species for each group of water and habitat quality class and to develop the first fish-based model for stream quality assessment in Serbia taking into account the regional specificity of the country. Fish samples were collected between 2003. and 2011. at 124 sampling sites, distributed along the Great Morava and Drina river basins (Black sea drainage basin) and 7 sites belonging to Aegean Sea drainage basin. The fish samples were patterned using an Artificial Neural Network (ANN) technique, the Kohonen self-organizing map (SOM), which is considered to be efficient tool in determining patterns of aquatic ecological assemblages. То explore spatial variaion of fish assemblages, only sites belonging to Great Morava river basin are considered and were patterned using the self-organizing map (SOM) based on fish biomass data. The SOM analysis distinguished two main clusters of samples collected on the Great Morava river basin, X and Y. The Y concerns the downstream areas, while the X was subdivided to the sub-clusters X1 (midstream areas) and X2 (upstream areas). Generally, the classification of the fish assemblages derived by SOM is in accordance with the a priori landscape classification to a greater extent. The significant anthropogenic influence is responsible for the misclassification of some particular sites. The classification strength (CS), derived from the fish community classification obtained by SOM, was higher than for a priori defined groups. Environmental parameters, which the landscape classification is based on, such as altitude and dominant substrate, are found to be very important for community structure. Also, the selforganizing map (SOM) was employed in order to group samples into their characteristic ecological entities (river types) depending on the character of the habitat they came from. Then, the k-means cluster analysis classified samples into four groups, each describing a particular ecological condition. The indicator species were presented for each group based on their constancy and dominance. Gradients over the SOM map were sought for eleven fish community metrics. Out of the total number of tested metrics, nine showed a clear gradient over the SOM map, but the Kruskall–Wallis ANOVA and Mann–Whitney tests pointed out that only three significantly differ among all groups. The results of this study reveal the spatial organization of fish communities which could help their implementation in rapid bioassessment programs. On the basis of the fish community metrics and selected indicator species, we proposed a fish-based index for the assessment of the ecological status of running waters in Serbia (fBNBI). The significance of our work lies on the fact that fBNBI is the first attempt regarding IBI (Index of Biotic Integrity) adjustment to the regional-specificity of Serbian running waters. It would be a clear benchmark to judge the ecological quality of lotic systems in Serbia and to identify waters most in need of protection or restoration. Finally, to assure the reliable and comprehensive assessment of ecological condition we feel that the BNBI and fBNBI should be employed simultaneously

U ovoj doktorskoj disertaciji ispitivani su citotoksični efekti koloidnih rastvora fulerenskih nanočestica, kao i uticaj mehanohemijski pripremljenih fulerena na citotoksičnost azot monoksida. Zbog sposobnosti da indukuju ćelijsku smrt u određenim uslovima, fulereni C60 predstavljaju potencijalne antitumorske i toksične agense. Koloidni rastvor kristalnog C60 (nC60) je izuzetno toksičan, ali mehanizmi njegove citotoksičnosti još uvek nisu dovoljno ispitani ni razjašnjeni. U ovoj studiji korišćena su tri različita načina pripreme nC60 rastvora: 1. metodom izmene rastvarača u tetrahidrofuranu (THF/nC60), 2. etanolu (EtOH/nC60) ili 3. produženim mešanjem u vodi (H2O/nC60). Kombinovanjem eksperimentalnih analiza i matematičkog modelovanja ispitivani su uslovi pod kojim različiti rastvori nC60 ispoljavaju citotoksičnost posredovanu reaktivnim kiseoničkim vrstama (RKV). Prema sposobnosti da generišu RKV i izazovu mitohondrijalnu depolarizaciju praćenu nekrozom, rastvori nC60 su rangirani sledećim redosledom: THF/nC60 > EtOH/nC60 > H2O/nC60. Matematičko modelovanje produkcije singletnog kiseonika (1O2) pokazuje da sposobnost rastvarača ugrađenog u strukturu fulerenskog kristala da neutrališe 1O2 (THF/nC60 < EtOH/nC60 < H2O/nC60) predstavlja presudni faktor koji određuje sposobnost nanočestice da proizvodi RKV i izaziva ćelijsko oštećenje. Ovi rezultati skreću pažnju na toksikološki aspekt koloidnih fulerena u njihovoj potencijalnoj upotrebi u biomedicini. Fulereni imaju dvojnu prirodu tako da osim što proizvode RKV kada su pobuđeni vidljivom svetlošću, oni deluju i kao ,,skupljači“ slobodnih radikala i ispoljavaju značajna antioksidativna svojstva. Iz tog razloga je, u drugom delu studije, ispitivan uticaj fulerenskih nanočestica na citotoksičnost azot monoksida (NO), veoma reaktivnog slobodnog radikala. Fulerenske nanočestice su pripremljene mehanohemijski potpomognutom kompleksacijom uz korišćenje anjonskog surfaktanta natrijum dodecil sulfata (SDS), makrocikličnog oligosaharidγa -ciklodekstrina (γCDX) ili kopolimera acetat-etilen vinil versatata (EVA-EVV) i karakterisane metodama UV-vis spektroskopije i mikroskopijom atomskih sila (AFM)... In this doctoral dissertation we investigated cytotoxic effects of fullerene colloidal suspensions, as well as the influence of mechanochemically synthesized fullerene C60 nanoparticles on the cytotoxicity of nitric oxide (NO). Because of their ability to induce cell death in certain conditions, fullerenes are potential toxic and anticancer agents. Colloidal suspension of crystalline C60 (nC60) is very toxic, but the mechanisms of its cytotoxicity are not completely explained. By combining experimental analysis and mathematical modeling, the requirements for the reactive oxygen species (ROS)- mediated cytotoxicity of different nC60 suspensions were investigated. Colloidal suspensions of nC60 were prepared by solvent exchange method in tetrahydrofuran (THF/nC60) and ethanol (EtOH/nC60), or by extended mixing in water (H2O/nC60). With regard to their capacity to generate RKV and cause mitochondrial depolarization followed by necrotic cell death, the nC60 suspensions were ranked in the following order: THF/nC60 > EtOH/nC60 > aqu/nC60. Mathematical modeling of singlet oxygen (1O2) generation indicates that the 1O2-quenching power (THF/ nC60 < EtOH/nC6 0

Flavonoidi se već duži niz godina nalaze u vrhu aktuelnosti fundamentalnih i primenjenih istraživanja iz razloga velike biološke i fiziološke aktivnosti, složenosti biosinteze i metabolizma kao i sve većih mogućnosti primene u raznim oblastima industrije. Pretpostavlja se da je biološka aktivnost flavonoida prvenstveno zasnovana na njihovom antioksidativnom delovanju koje se ispoljava višestruko, u direktnim interakcijama sa slobodnim radikalima (antiradikalska aktivnost) kao i indirektno u reakcijama kopigmentacije, inhibicije enzima, eliminaciji singletnog kiseonika, smanjenju stepena lipidne peroksidacije, zaustavljanju faze propagacije u kojoj nastaju hidro-peroksi lipidi, detoksifikaciji vodonik peroksida u ne-enzimskim mehanizmima odbrane ili uklanjanjem oksidacijom oštećenih biomolekula i u reakcijama kompleksiranja sa jonima prelaznih metala. Sa druge strane flavonoidi mogu da deluju i kao redukcioni agensi čime menjaju redoks svojstva prelaznih metala sa kojima grade komplekse što im, pod određenim uslovima, daje mogućnost i prooksidativnog delovanja. Iako su reakcije komplekisranja flavonoida i metalnih jona do sada bile predmet mnogih naučnih istraživanja rezulatati na tom polju, posebno oni koji se odnose na kompleksiranje u vodenoj sredini, nisu u potpunosti usaglašeni, a često su i kontradiktorni po pitanju definisanja mehanizma reakcije, helatnih položaja molekula uključenih u strukturu nagrađenih kompleksa, stehiometrije i stabilnosti kompleksa. U ovoj doktorskoj disertaciji predstavljeni su rezultati in vitro ispitivanja reakcije kompleksiranja odabranih hidroksi-flavonskih molekula različitih supstitucionih shema (kvercetin, fisetin, morin i baikalein) i gvožđe(III) jona. Određeni su optimalni uslovi za odigravanje reakcije i razmatran je uticaj strukture molekula na stabilnost i stehiometrijski sastav kompleksa. Takođe, istraživanja u okviru ove... Due to their high biological and physiological activity, biosyntheses and metabolism complexity, as well as to the growing possibilities of their application in the various fields of industry, the flavonoids have been for many years extremely popular in both fundamental and applied research. It is believed that the biological activity of the flavonoids is primarily based on their antioxidative action which is manifested in various ways: both in the direct interaction with free radicals (antiradical activity) and indirectly in the copigmentation reactions, inhibition of the enzymes, the elimination of singlet oxygen, reduction of lipid peroxidation, stopping the propagation stage in which hydro-peroxy lipids are generated, detoxification of hydrogen peroxide in nonenzymatic defense mechanisms or removing damaged biomolecules by oxidation and in transition metal complexation reactions of flavonoids. On the other hand, flavonoids can act as reducing agents altering the redox properties of transition metal complexes, which, under certain conditions, give them an ability of prooxidative activity. Although the reactions of flavonoids and metal ions complexation has been the subject of many scientific research, the results in this field, particularly those relating to the complexation in aqueous media, are not fully harmonized, and are often contradictory in terms of defining the mechanism of the reaction, the position of chelating molecules involved in the structure of these complexes, the stoichiometry and stability of complexes. Within the scope of this doctorial thesis, in vitro complexation reactions of the selected hidroxy-flavon molecules, with various substitution variations (quercetin, fisetin, morin, baicalein), and iron(III) ion are investigated. The optimal conditions of the reactions are determined as well as the influence of the molecular structure on the complex stoichiometry. Also, the research within this thesis involve the examination of the activity of pure molecules and their complexes towards a few differently nitrogen...

Rezime: Istraživanja koja su realizovana u okviru ove doktorske disertacije imala su za cilj da daju doprinos proučavanju promena hemijskog i masnokiselinskog sastava šarana (Cyprinus carpio) gajenog u dva ribnjaka sa poluintenzivnim uzgojem, u zavisnosti od vrste dodatne hrane (ekstrudirana hrana i kukuruz), u završnoj fazi uzgoja dvogodišnje ribe za konzum. Rast i povećanje mase ribe povezano je sa povećanjem sadržaja proteina, lipida, vlage, mineralnih materija, itd. Količine hranljivih materija koje su se deponovale u mesu šarana u toku uzgoja i prihranjivanja sa dve vrste dodatne hrane analizirane su alometrijskom i izometrijskom linearnom regresijom. Uticaj dodatne hrane procenjen je poređenjem izometrijskih koeficijenata b pomoću t testa. Rezultati su pokazali da se prihranjivanjem šarana ekstrudiranom hranom tokom uzgoja deponovala veća količina proteina u mesu ribe, dok se prihranjivanjem šarana kukuruzom deponovala veća količina lipida. Višestrukom linearnom regresijom (MLR) utvrđen je odnos između sadržaja proteina, lipida i vlage u mesu šarana, kao i doprinos koji su proteini i lipidi imali u povećanju mase šarana. Dobijeni rezultati su značajni za bolje razumevanje biohemijskih procesa koji se odigravaju u toku rasta šarana. U cilju definisanja razlika u hemijskom sastavu i sastavu masnih kiselina između, ukupno, 62 uzorka šarana, prema vrsti dodatne hrane, korišćene su analiza varijansi i multivarijantna analiza glavnih komponenti (PCA). Rezultati su pokazali da je sadržaj proteina (P < 0,01) i vlage (P < 0,001) bio značajno veći kod šarana prihranjivanih ekstrudiranom hranom, dok je sadržaj lipida bio značajno veći (P < 0,001) kod šarana prihranjivanih kukuruzom. Šarani se nisu značajno razlikovali u sadržaju pepela. Prema vrsti prihrane, šarani se nisu razlikovali u sadržaju zasićenih masnih kiselina. Mononezasićene masne kiseline su bile značajno veće kod šarana prihranjivanih kukuruzom (P < 0,0001), u svim mesecima izlova, u odnosu na šarane prihranjivanih ekstrudiranom hranom... Abstract: The studies that have been carried out in the framework of the present doctoral thesis were aimed to contribute to the study of changes in the chemical and fatty acid composition of common carp (Cyprinus carpio) farmed in two fish farms with semi-intensive farming, depending on the type of supplementary feed (extruded feed and corn), in the final stage of farming of two-year fish for consumption. The growth and increase in body weight of the fish are associated with the increase in the content of proteins, lipids, moisture, mineral substances, etc. The amount of nutrients that had been deposited in the flesh of common carp during the farming and additional nutrition with two supplemental types of feed was analysed using the allometric and isometric linear regression. The effect of the supplemental feed was evaluated by comparing isometric coefficients b by the use of t test. The results showed that the use of extruded feed in carp farming resulted in deposition of greater amounts of proteins in the fish meat, while the use of corn in nutrition of carp influenced deposition of greater amounts of lipids. Multiple linear regression (MLR) was used to determine the relationship between the contents of proteins, lipids and moisture in the meat, as well as the contribution of proteins and lipids in the increase of the body mass of carp. The results obtained are important for a better understanding of the biochemical processes that take place during the growth of carp. In order to establish differences in the chemical composition and the fatty acid profiles among a total of 62 samples of carp, according to the type of supplementary feed, analysis of variance and multivariate principal components analysis (PCA) were used. The results showed that the protein (P < 0.01) and moisture content (P < 0.001) were significantly higher in carp supplementary fed extruded feed, while the content of lipids was significantly higher (P < 0.001) in carp supplementary fed corn. Carp were not significantly different in ash content. According to the type of supplementary feed, carp did not differ in the content of saturated fatty acids...

Carp (Cyprinus carpio L., 1758) is one of the most important fish species in Serbian, European and World aquaculture... Šaran (Cyprinus carpio L., 1758) je jedna od najznačajnijih vrsta za srpsku, evropsku i svetsku akvakulturu...

Šaran se gaji u sva tri sistema gajenja: ekstenzivni, poluintenzivni i intenzivni. Za razliku od ekstenzivnog gde prirast ribe iskljuĉivo zavisi od prirodne hrane, poluintenzivni i intenzivni sistemi su bazirani na delimiĉnoj ili potpunoj zavisnosti od dodatne hrane. Kako tokom sezone gajenja, prirodna hrana u ribnjacima sa poluintenzivnim sistemom ima veoma izraţen sezonalni karakter, u periodu sa optimalnim temperaturama za rast šarana (od sredine juna pa do kraja avgusta) prirast je u najvećoj meri zavistan od kvaliteta i koliĉine dodatne hrane. Sa ekonomskog, ali i ekološkog aspekta vaţno je obezbediti hranu koja će zadovoljiti nutritivne potrebe riba, rezultirati niskim koeficijentom konverzije, visokim tempom rasta, dobrim zdravstvenim stanjem gajenih riba, visokim kvalitetom finalnog proizvoda, odnosno ribljeg mesa i što manjim opterećenjem vodene sredine organskim materijama, fosforom i azotom. Nutritivna svojstva hrane za ribe u velikoj meri zavise od udela proteina i masti. Veoma je vaţno da osnovnih komponenti u hrani za ribe ne bude manje od potreba gajenih riba, ali i sa ekonomskog aspekta da ih u hrani ne bude više od koliĉine koju ribe mogu iskoristiti. Proteini kao gradivne komponente, su veoma vaţni za izgradnju tela ali i za brojne fiziološke procese u organizmu. Njihovo poreklo, sastav, kao i koliĉina u smešama od presudnog su znaĉaja za iskoristivost hrane i prirast gajenih riba. Najpoţeljnija komponenta, kao nosilac proteina odgovarajućeg aminokiselinskog sastava, za proizvodnju hrane za karnivorne vrste riba, ali i za intenzivno gajenje omnivornih riba je riblje brašno. Zbog deficita ovog veoma vaţnog hraniva na svetskoj pijaci i visoke cene na trţištu, riblje brašno, kao i ostala hraniva animalnog porekla se kombinuju ili pak potiskuju sa alternativnim biljnim izvorima proteina, uz optimizaciju koliĉine u obroku i uz stalnu teţnju da se što veći procenat ribljeg brašna potisne iz hrane. Masti prisutne u hrani doprinose efikasnijem iskorišćavanju proteina iz obroka, zahvaljujući ĉemu se skuplji proteini ĉuvaju od neracioanlnog iskorišćavanja kao dodatni izvor energije. U okviru odreĊenih granica, povećanje nivoa lipida u obroku, dovodi do poboljšanog iskorišćavanja hrane, tako što se lipidi koriste za obezbeĊivanje biološki korisne energije i na taj naĉin se štede proteini... Carp is cultured in all the 3 systems: extensive, semiintensive and intensive. Contrary to extensive rearing where weight gain depends exclusively on natural food, semiintensive and intensive systems are based on partial or complete reliance on added feed. During the rearing season the natural food in fish ponds with the semiintensive system has a prominent seasonality: in the period of natural food depression with optimal temperatures for carp growth (from mid June to the end of August) weight gain is primarily dependent on the quality and quantity of added feed. From an economical, and also an ecological point of view it is important to supply feed that will meet nutritional requirements of fish, and result in low feed conversion coefficient, high growth rate, good health condition, high quality of the final product – fish meat, and as low as possible load of the aquatic environment with organic matter, phosphorus, and nitrogen. Nutritional properties of fish feed are highly dependent on the protein and fat level. It is of utmost importance to stress that the amount of basic components in feed should not be fewer than the requirements of farmed fish, though, particularly from the economic point of view, this amount should’t be too high since the fish will not be able to utilise it. As the main building blocks, proteins are essential for body growth and a number of physiological processes. Their origin and quantity in feed mixtures are of crucial importance for the utilization of feed and growth of cultured fish. Fishmeal is the most desirable component of the feed that provides proteins with good amino acid composition in feed for carnivorous fish species, as well as for omnivorous fish in intensive production. Due to the deficit of this very important nutrient at the world market and their high prices, fishmeal and other feed of animal origin are combined or replaced with alternative sources of plant proteins. There is a constant tendency towards decreasing the share of fishmeal in feed while optimizing the amount of proteins in the meal...

Doktorska disertacija obuhvata ekološku analizu zajednica makrozoobentosa reke Nišave i njihovu zavisnost od biotičkih i abiotičkih faktora. Istraživanja su obavljena mesečnom dinamikom na dvanaest lokaliteta od maja 2006. do aprila 2007. godine. U disertaciji se diskutuje zavisnost koncentracije hlorofila a i mase perifitona od abiotičkih faktora. Sa druge strane, razmatran je pritisak (na osnovu brojnosti) filtratornih vrsta zajednice makroinvertebrata na količinu fitoplanktona (izraženu preko hlorofila a) i pritisak grebača na masu perifitona. Dobijen je predikcioni model za izračunavanje koncentracije hlorofila a korišćenjem multiple linearne regresije. Model ima značajnu predikcionu moć (sig=0,003). Na osnovu Pirsonovog koeficijenta korelacije konstatovano je da postoji značajna povezanost koncentracije hlorofila a sa mutnoćom (p=0,000), sa ukupnim fosforom (p=0,029) i sa kombinovanom (zbirnom) koncentracijom ukupnog azota i fosfora (p=0,036). Nije utvrđena značajna povezanost sa brojnošću filtratornih organizama, što govori da njihov pritisak nije dovoljno jak da bi limitirao količinu fitoplanktona. Taksonomskom analizom makroinvertebrata reke Nišave utvrđeno je prisustvo 132 vrste iz 4 različita filuma. Filum Platyhelminthes je predstavljen sa 3 vrste iz 2 familije. Filum Annelida obuhvata 23 vrste iz 6 familija. Najveći broj vrsta ovog filuma pripada potklasi Oligochaeta (16 vrsta). Filum Mollusca obuhvata 13 vrsta iz 5 familija, od kojih 11 pripada klasi Gastropoda, a 2 klasi Bivalvia. Najveći broj vrsta faune makroinvertebrata pripada filumu Arthropoda (92 vrste iz 33 familije), od kojih 3 pripadaju subfilumu Crustacea, a sve ostale podfilumu Hexapoda, odnosno klasi Insecta. Rezultati taksonomske analize pojedinačnih grupa u okviru zajednice makroinvertebrata pokazuju da najveći broj vrsta pripada grupi Ephemeroptera (28 vrsta), zatim slede Diptera (26 vrsta) i Trichoptera (20 vrsta). Ostale grupe su zastupljene sa manjim brojem vrsta. Diskutovana je sezonska i longitudinalna dinamika grupa makroinvertebrata i njihova uslovljenost faktorima sredine. Razmatrani su indeksi diverziteta i adekvatnost njihovog korišćenja kao pokazatelja zagađenosti ekosistema, posebno za svaku grupu... This doctoral dissertation comprises the ecological analysis of macrozoobenthos communities in the Nišava River and their dependence on biotic and abiotic factors. The studies followed the monthly dynamics at 12 sites, from May 2006 to April 2007. The dissertation is discussing the dependence of chlorophyll a concentration and periphyton mass on abiotic factors, as well as the pressure (based on abundance) of filtrating species in the macroinvertebrate community on the amount of phytoplankton (expressed as chlorophyll a) and pressure of scraper species on periphyton mass. The prediction model for calculating chlorophyll a concentration was derived from the multiple linear regression. This model has a significant prediction power (sig=0.003). The Pearson's correlation coefficient was used to determine the correlation of chlorophyll a concentration with water turbidity (p=0.000), total phosphorus (p=0.029) and combined (summative) concentration of total nitrogen and total phosphorus (p=0.036). No significant connection with the abundance of filtrating organisms was determined, which indicates that their pressure was not strong enough to limit the quantity of phytoplankton. The taxonomic analysis of macroinvertebrates in the Nišava River yielded the presence of 132 species from 4 different phyla. The phylum Platyhelminthes was represented with 3 species from 2 families. The phylum Annelida was represented with 23 species from 6 families. Most recorded species from this phylum belong to the subclass Oligochaeta (16 species). The phylum Mollusca was represented with 13 species from 5 families, of which 11 were from the class Gastropoda and 2 from the class Bivalvia. Most species of the macroinvertebrate fauna belong to the phylum Arthropoda (92 species from 33 families), of which 3 were from the subphylum Crustacea, while all others belong to the subphylum Hexapoda and class Insecta. The results of the taxonomic analysis of individual groups within the macroinvertebrate community have shown that most species belong to the group Ephemeroptera (28 species), followed by Diptera (26 species), and Trichoptera (20 species). Other groups were represented with a smaller number of species. The study also includes the discussion on seasonal and longitudinal dynamics of macroinvertebrate groups and the effect of environmental factors on their presence. The diversity indices and their suitability as indicators of ecosystem pollution were discussed for each group separately...