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Cell growth and the level of alpha-amylase in response to the carbon and nitrogen sources used for the growth of the strain Bacillus subtilis IP 5832 were examined. Based on the amylase productivity level in shake flask cultures after 24 hours of growth, the growth medium containing starch and peptone was selected as the best medium. Amylase production was greatly reduced when glutamate or citrate as sources of carbon were used. Experiments performed at different initial concentrations of starch showed that although the strain grew well with all the starch concentration used, 0.5 % starch was necessary for maximum alpha-amylase production, inducing 1.55 IU mL(-1) of amylase to be secreted after 8 h of cultivation in shaking flasks. During the batch fermentation of B. subtilis IP 5832 strain in 2 L laboratory fermenter, a 60 % higher activity (2.5 IU mL(-1)) was obtained. The production of the enzyme was directly related to the growth of the strain. Maximum enzyme activity was obtained at the beginning of the stationary growth phase. Ćelijski rast i nivoi α-amilaze nakon gajenja Bacillus subtilis IP 5832 ispitivani su u zavisnosti od različitih izvora ugljenika i azota korišćenih u podlozi. Na osnovu produktivnosti amilaze nakon dvadesetčetvoročasovnog gajenja kulture u erlenmajerima sa mešanjem pokazano je da je najbolja hranljiva podloga ona koja sadrži skrob i pepton. Kada su glutamat ili citrat korišćeni kao izvori ugljenika produkcija enzima je bila značajno redukovana. Eksperimentima u kojima je varirana inicijalna koncentracija skroba pokazano je da je, iako soj dobro raste na svim korišćenim koncentracijama, 0,5 % skrob neophodan za maksimalnu produkciju enzima, indukujući sekreciju 1,55 IU mL-1 amilaze nakon 8 sati gajenja kulture u erlenmajerima sa mešanjem. Tokom šaržne fermentacije B. subtilis IP 5832 soja u laboratorijskom fermentoru od 2 L dobijeno je 60 % više aktivnosti enzima (2,5 IU mL -1). Produkcija enzima je bila direktno vezana za rast mikroorganizma. Maksimalna enzimska aktivnost dobijena je na početku stacionarne faze rasta.

The consumption of dyes is increasing worldwide in line with the increase of population and demand for clothes and other colored products. However, the efficiency of dyeing processes is still poor and results in large amounts of colored effluents. It is desired to develop a portfolio of enzymes which can be used for the treatment of colored wastewaters. Herein, we used genome sequence information to discover a dye-decolorizing peroxidase (DyP) from Pseudomonas fluorescens Pf-01. Two genes putatively encoding for DyPs were identified in the respective genome and cloned for expression in Escherichia coli, of which one (PfDyP B2) could be overexpressed as a soluble protein. PfDyP B2 shows some typical features known for DyPs which includes the ability to convert dyes at the expense of hydrogen peroxide. Interestingly, t-butyl hydroperoxide could be used as an alternative substrate to hydrogen peroxide. Immobilization of PfDyP B2 in calcium-alginate beads resulted in a significant increase in stability: PfDyP B2 retains 80% of its initial activity after 2 h incubation at 50 &deg, C, while the soluble enzyme is inactivated within minutes. PfDyP B2 was also tested with aniline and ethyl diazoacetate as substrates. Based on GC-MS analyses, 30% conversion of the starting material was achieved after 65 h at 30 &deg, C. Importantly, this is the first report of a DyP-catalyzed insertion of a carbene into an N-H bond.

Natural amylase producers, wild type strains of Bacillus sp., were isolated from different regions of Serbia. Strains with the highest amylase activity based on the starch-agar plate test were grown on solid-state fermentation (SSF) on triticale. The influence of the substrate and different cultivation temperature (28 and 37°C) on the production of amylase was examined. The tested strains produced α-amylases when grown on triticale grains both at 28 and at 37°C, but the activity of amylases and the number and intensity of the produced isoforms were different. Significant hydrolysis of raw cornstarch was obtained with the Bacillus sp. strains 2B, 5B, 18 and 24B. The produced α-amylases hydrolyzed raw cornstarch at a temperature below the temperature of gelatinization, but the ability for hydrolysis was not directly related to the total enzyme activity, suggesting that only certain isoforms are involved in the hydrolysis. [Projekat Ministarstva nauke Republike Srbije, br. 172048]

Several natural isolates of Bacillus strains namely 5B, 12B, 16B, 18 and 24B were grown on two different temperatures in submerged fermentation for the raw-starch-digesting a-amylases production. All strains except Bacillus sp. 18 produced more α-amylase on 37oC. The hydrolysis of raw corn starch followed same pattern. Efficient hydrolysis was obtained with α-amylases from Bacillus sp. 5B, 12B, 16B and 24B grown on 37oC and Bacillus sp. 18 grown on 50oC. Zymography after isoelectric focusing shown that α-amylases were produced in multiple forms, from 2 to 6, depending on the strain when they were growing at 37 oC, while growing at 50oC induced only 1 or 2 isoforms. TLC analysis of hydrolysis products of raw corn and soluble starch by α-amylases revealed production of various mixtures of oligosaccharides. In most cases G3 was the most dominant product from soluble starch while G2, G3 and G5 were the main products of raw starch hydrolysis. This indicates that obtained a-amylases can be used for starch liquefying or short-chain-oligosaccharide forming, depending on what type of starch (raw or soluble) was used for the hydrolysis. [Projekat Ministarstva nauke Republike Srbije, br. 172048]

Introduction. Carbohydrate-deficient transferrin (CDT) has been suggested as one of alcohol abuse indicators having produced good results in forensic medicine for years. Objective. The aim of the study was to identify correlation between present methodology of alcohol abuse diagnosis at autopsy (macroscopic and microscopic findings) and CDT examination using the method of isoelectrofocusing (IEF) in polyacrylamide gel electrophoresis (PAGE). We also analyzed if the time interval between the moment of death and blood sample collection influences CDT findings. Methods The method used for CDT analysis was IEF-PAGE. Sera of 49 males and 11 females aged 14-87 years, average age 46.85±18.53, were used in this study. Control group consisted of five patients who died after medical treatment that lasted longer than 15 days, and five patients who started Disulfiram therapy in controlled hospital environment. Results. The results obtained in CDT examination in dead bodies’ sera showed sensitivity 59% and specificity 71%. A high incidence of falsely positive CDT result was noticed in liver failure and cirrhosis of non-alcoholic origin. CDT analysis is also possible to be done in samples collected postmortem up to 76 hours. Conclusion. In forensic medicine, the method of CDT determination is reliable for the diagnosis of alcohol abuse.

Phenols containing halogens, which tend to deactivate the aromatic nuclei, constitute a significant category of highly toxic and difficult-to-degrade pollutants, which arise from a wide variety of industries. The main purpose of this study was to obtain an inexpensive immobilized enzyme for the removal of phenols. Partially purified potato polyphenol oxidase (PPO) was immobilized onto different commercial and laboratory produced carriers. Three of the obtained biocatalysts, with the highest PPO activities, namely Eupergit C250L-PPO; Celite-PPO and CelluloseM-PPO, were tested in a batch reactor for the removal of phenol, 4-chlorophenol and 4-bromophenol. In the case of 2.5 mM substrates with Eupergit C250L-PPO, an around 45 % removal of 4-bromophenol was achieved, while the removals 4-chlorophenol and phenol were 35 and 20 %, respectively. The reusability of Eupergit C250L-PPO for the removal of 4-chlorophenol was tested. After eight repeated tests, the efficiency of 4-chlorophenol removal by Eupergit C250L-PPO immobilisate had decreased to 55 %. Halogenovani fenoli imaju dezaktivirano aromatično jezgro i čine značajnu kategoriju veoma toksičnih i teško razgradivih zagađivača u raznim industrijskim granama. Glavni cilj ovog rada je bio dobijanje jeftinog imobilizovanog enzima za uklanjanje fenola. Delimično prečišćena polifenol-oksidaza (PFO) iz krompira je imobilizovana na različitim komercijalnim i laboratorijski sintetizovanim nosačima. Od dobijenih biokatalizatora, tri sa najvećim aktivnostima PPO, nazvani Eupergit C250L-PFO; Celit-PFO i CelulozaM-PFO, testirani su u reaktoru za uklanjanje fenola, 4-hlorfenola i 4-bromfenola. U slučaju 2,5 mM supstrata sa Eupergit C250L-PFO, postignuto je oko 45 % razgradnje 4-bromfenola, dok su 4-hlorfenol i fenol razgrađeni 35, odnosno 20 %. Testirana je i sposobnost višestruke upotrebe Eupergit C250L-PFO imobilizata za uklanjanje 4-hlorfenola. Nakon osam ponovljenih ciklusa efikasnost Eupergit C250L-PFO imobilizata za uklanjanje 4-hlorfenola je pala na 55%.

The pH along the midgut of M. funereus larvae had different values, being acidic in the anterior section and basic in the middle and posterior sections. Elastase- and chymotrypsin-like activities were highest in the middle, low in the anterior, and negligible in the posterior section of the midgut. Trypsin-like activities were detected along the whole midgut, with more than 90% of activity in the anterior section. The level of elastase- and chymotrypsin-like activity was very low compared to trypsin-like activity. In the anterior section of the midgut, two isoforms of trypsin-like enzymes were found, both being basic and almost completely inhibited by benzamidine. pH vrednost duž srednjeg creva larvi M. funereus se razlikuje, kisela je u regionu prednjeg dela, dok je u srednjem i zadnjem delu bazna. Elastazama i himotripsinima slična aktivnost je najveća u srednjem delu srednjeg creva dok je u prednjem delu detektovana mala vrednost, a u zadnjem delu zanemarljiva. Tripsinima slična aktivnost je detektovana duž celog srednjeg creva, s tim da se više od 90 % aktivnosti detektuje u prednjem delu srednjeg creva. Zastupljenost elastazama i himotripsinima sličnih endopeptidaza je zanemarljivo mala u poređenju sa zastupljenošću tripsinima sličnih enzima. U prednjem delu srednjeg creva nalaze se dve izoforme tripsinima sličnih enzima, sa baznim pI vrednostima, koje su skoro u potpunosti inhibirane benzamidinom.

Application of specific chromogenic substrates, use of class-specific inhibitors, and zymogram analysis enabled us to identify several peptidase classes in extracts of the midgut of Morimus funereus larvae. Zymogram analysis with gelatin as a peptidase substrate and phenylmethylsulfonyl fluoride as an inhibitor showed that serine peptidases were the most abundant endopeptidases in the midgut of M. funereus larvae. By zymogram analysis with gelatin as a peptidase substrate and 1,10-phenanthroline as an inhibitor, metallopeptidases were also detected. Analyses of serine peptidases with specific chromogenic substrates revealed dominance of elastase-like peptidases in extracts of the midgut of M. funereus larvae, with less pronounced chymotrypsin- and trypsin-like activities. Primenom specifičnih hromogenih supstrata, klasno-specifičnih inhibitora i zimogramske analize identifikovano je nekoliko klasa peptidaza u sirovom ekstraktu srednjeg creva larvi koleoptere Morimus funereus. Zimogramskom analizom sa želatinom kao supstratom i fenilmetilsulfonil-fluoridom kao inhibitorom utvrđeno je da su serin-peptidaze najzastupljenije peptidaze u ekstraktu srednjeg creva larvi M. funereus. Zimogramskom analizom sa želatinom kao supstratom i 1,10-fenantrolinom kaoinhibitorom takođe su detektovane metalopeptidaze. Analizom serin-peptidaza, upotrebom specifičnih hromogenih supstrata, dokazano je da su dominantni elastazi-slični enzimi u sirovom ekstraktu srednjeg creva larvi M. funereus, dok su himotripsinima- i tripsinima-slični enzimi manje zastupljeni.

The avarone/avarol quinone/hydroquinone couple shows considerable antitumor activity. In this work, covalent modification of ?-lactoglobulin by avarone and its derivatives as well as by the synthetic steroidal quinone 2,5(10)-estradiene- 1,4,17-trione and its derivatives were studied. The techniques for studying chemical modification of ?-lactoglobulin by quinones were: UV/Vis spectrophotometry, SDS PAGE and isoelectrofocusing. SDS PAGE results suggest that polymerization of the protein occurs. It could be seen that the protein of 18 kD gives the bands of 20 kD, 36 kD, 40 kD, 45 kD, 64 kD and 128 kD depending on modification agent. The shift of the pI of the protein (5.4) upon modification toward lower values (from pI 5.0 to 5.3) indicated that lysine amino groups are the principal site of the reaction of ?-lactoglobulin with the quinones.

alpha-Amylase isoforms of Cerambyx cerdo larvae from the wild (ML and SL) and reared in the laboratory (ADL) were compared. Three amylase isoforms were presented in the SL and ML extracts while two isoforms were presented in the ADL according to zymogram after isoelectric focusing (IEF). All C. cerdo amylase isoforms were acidic proteins (pI lt 3.5). Seven amylase isoforms (ACC 1-7) from the midgut of C. cerdo larvae were found in the ML midgut extract, six in the SL extract, and four in the ADL extract according to native PAGE zymogram. The ADL amylase had the highest activity. All crude midgut extracts of C. cerdo larvae were fractionated on a Superose 12 HR column. The molecular mass of the ACC was estimated to be 34 kDa. Upoređene su izoforme α-amilaze larvi Cerambyx cerdo sakupljenih iz prirode (ML i SL) i gajenih na veštačkoj podlozi u laboratoriji (ADL). Zimogramskom detekcijom posle IEF-a po tri izoforme su detektovane u ML i SL ekstraktima, a u ADL dve izoforme. Sve amilazne izoforme iz C. cerdo su bile kisele (pI lt 3.5). Zimogramskom detekcijom posle nativne elektroforeze sedam izoformi je detektovano u ML ekstraktu, šest u SL ekstraktu i četiri u ADL ekstraktu. Najveća amilazna aktivnost je detektovana u ADL ekstraktu. Svi ekstrakti srednjih creva larvi C. cerdo su frakcionisani na koloni Superose 12 HR. Molekulska masa ACC-a je bila 34 kDa.

Using soluble starch as a substrate five isoforms of alpha-amylase were identified in a crude extract of Morimus funereus larvae. The main alpha-amylase (termed AMF-3) was purified by gel filtration chromatography and anion exchange chromatography to obtain a single band on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Its enzymatic purity was confirmed by an in-gel activity assay after SDS-PAGE. The purity of AMF-3 was increased 112-fold with a 15.4% yield. AMF-3 had apparent molecular masses of 33 and 31 kDa when analysed using SDS-PAGE and Superdex 75 FPLC gel filtration chromatography, respectively and a calculated isoelectric point of 3.2. Purified AMF-3 showed maximal activity at pH 5.2 and had an optimum activity temperature of 45 degrees C. AMF-3 retained over 90% of its maximum activity at temperatures from 45 to 60 degrees C. AMF-3 exhibited a high affinity towards soluble starch with a K-m value of 0.43 mg/mL. Maximal AMF-3 activity was achieved in the presence of 0.1 mM CaCl2, while at higher concentrations its activity decreased. AMF-3 activity increased with increasing NaCl concentration. AMF-3 activity was significantly inhibited by alpha-amylase wheat inhibitor. Using a number of raw starch substrates maximum AMF-3 activity was achieved with horse-radish starch, in contrast to undetectable activity towards potato starch. (C) 2007 Elsevier Inc. All rights reserved.

Ixodes ricinus Linnaeus (Acari: Ixodidae) ticks are vectors of numerous infectious diseases in humans and animals. The allozyme variability of MDH and alpha-Gpdh was detected by native polyacrylamide gel electrophoresis in I. ricinus natural populations in three localities in Serbia. Four alleles of Mdh locus (MDH 1, MDH 2, MDH 3 and MDH X) and four alleles of alpha-Gpdh locus (VS, S, F and VF) were detected. Interpopulation differences in Mdh and alpha-Gpdh allele frequencies were statistically insignificant. Significant difference in alpha-Gpdh allele frequencies between mates and females was recorded in the largest sample only. Differences in allele frequencies, detected between borreliae-infected and uninfected I. ricinus ticks, were close to the level of statistical significance, especially for alpha-Gpdh locus. Clear significant difference appeared in females when sexes were tested separatelly (P = 0.037). It is interesting that genotypes containing rarer alleles (MDH 1 and S) were infected in higher proportion in comparison to other genotypes. Our results point towards a possible role of Mdh and alpha-Gpdh loci in I. ricinus ticks in the determination of energy requirements for host seeking. Sex differences in alpha-Gpdh allele frequencies suggest that selective pressure, concerning efficiency of reserve materials utilisation, points to alpha-Gpdh rather than to Mdh locus.

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