29 results on '"Buivydas, Andrius"'
Search Results
2. Discovering genetic determinants for cell-to-cell adhesion in two prevalent conjugative lactococcal plasmids
- Author
-
Ortiz Charneco, Guillermo, Kelleher, Philip, Buivydas, Andrius, de Waal, Paul P., van Rijswijck, Irma M.H., van Peij, Noël N.M.E., Cambillau, Christian, Mahony, Jennifer, and Van Sinderen, Douwe
- Published
- 2024
- Full Text
- View/download PDF
3. Transcriptional control of two distinct lactococcal plasmid-encoded conjugation systems
- Author
-
Ortiz Charneco, Guillermo, Kelleher, Philip, Buivydas, Andrius, de Waal, Paul P., van Rijswijck, Irma M.H., van Peij, Noël N.M.E., Mahony, Jennifer, and Van Sinderen, Douwe
- Published
- 2024
- Full Text
- View/download PDF
4. Discovering genetic determinants for cell-to-cell adhesion in two prevalent conjugative lactococcal plasmids
- Author
-
Charneco, Guillermo Ortiz, primary, Kelleher, Philip, additional, Buivydas, Andrius, additional, de Waal, Paul P., additional, van Rijswijck, Irma M.H., additional, van Peij, Noël N.M.E., additional, Cambillau, Christian, additional, Mahony, Jennifer, additional, and Van Sinderen, Douwe, additional
- Published
- 2024
- Full Text
- View/download PDF
5. Plasmid‐mediated horizontal gene mobilisation: Insights from two lactococcal conjugative plasmids.
- Author
-
Ortiz Charneco, Guillermo, McDonnell, Brian, Kelleher, Philip, Buivydas, Andrius, Dashko, Sofia, de Waal, Paul P., van Rijswijck, Irma, van Peij, Noël N. M. E., Mahony, Jennifer, and Van Sinderen, Douwe
- Subjects
GENES ,PHENOTYPES ,PLASMIDS - Abstract
The distinct conjugation machineries encoded by plasmids pNP40 and pUC11B represent the most prevalent plasmid transfer systems among lactococcal strains. In the current study, we identified genetic determinants that underpin pNP40‐ and pUC11B‐mediated, high‐frequency mobilisation of other, non‐conjugative plasmids. The mobilisation frequencies of the smaller, non‐conjugative plasmids and the minimal sequences required for their mobilisation were determined, owing to the determination of the oriT sequences of both pNP40 and pUC11B, which allowed the identification of similar sequences in some of the non‐conjugative plasmids that were shown to promote their mobilisation. Furthermore, the auxiliary gene mobC, two distinct functional homologues of which are present in several plasmids harboured by the pNP40‐ and pUC11B‐carrying host strains, was observed to confer a high‐frequency mobilisation phenotype. These findings provide mechanistic insights into how lactococcal conjugative plasmids achieve conjugation and promote mobilisation of non‐conjugative plasmids. Ultimately, these insights would be harnessed to optimise conjugation and mobilisation strategies for the rapid and predictable development of robust and technologically improved strains. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Delineation of a lactococcal conjugation system reveals a restriction‐modification evasion system
- Author
-
Ortiz Charneco, Guillermo, primary, Kelleher, Philip, additional, Buivydas, Andrius, additional, Dashko, Sofia, additional, de Waal, Paul P., additional, van Peij, Noël N. M. E., additional, Roberts, Richard J., additional, Mahony, Jennifer, additional, and van Sinderen, Douwe, additional
- Published
- 2023
- Full Text
- View/download PDF
7. Heterologous biosynthesis and characterization of a glycocin from a thermophilic bacterium
- Author
-
Kaunietis, Arnoldas, Buivydas, Andrius, Čitavičius, Donaldas J., and Kuipers, Oscar P.
- Published
- 2019
- Full Text
- View/download PDF
8. Major gene‐regulatory mechanisms operating in ribosomally synthesized and post‐translationally modified peptide (RiPP) biosynthesis
- Author
-
Bartholomae, Maike, Buivydas, Andrius, Viel, Jakob H., Montalbán‐López, Manuel, and Kuipers, Oscar P.
- Published
- 2017
- Full Text
- View/download PDF
9. Purification of Peptide Antimicrobials and Thioether-Stabilized Molecules Produced In Vivo by Lantibiotic Modification Machineries
- Author
-
Montalban-Lopez, Manuel, primary, Buivydas, Andrius, additional, and Kuipers, Oscar P., additional
- Published
- 2015
- Full Text
- View/download PDF
10. Genetic Dissection of a Prevalent Plasmid-Encoded Conjugation System in Lactococcus lactis
- Author
-
Ortiz Charneco, Guillermo, primary, Kelleher, Philip, additional, Buivydas, Andrius, additional, Streekstra, Hugo, additional, van Themaat, Emiel Ver Loren, additional, de Waal, Paul P., additional, Mahony, Jennifer, additional, and van Sinderen, Douwe, additional
- Published
- 2021
- Full Text
- View/download PDF
11. Prospects of In vivo Incorporation of Non-canonical Amino Acids for the Chemical Diversification of Antimicrobial Peptides
- Author
-
Baumann, Tobias, primary, Nickling, Jessica H., additional, Bartholomae, Maike, additional, Buivydas, Andrius, additional, Kuipers, Oscar P., additional, and Budisa, Nediljko, additional
- Published
- 2017
- Full Text
- View/download PDF
12. Transcriptional control of two distinct lactococcal plasmid-encoded conjugation systems
- Author
-
Charneco, Guillermo Ortiz, Kelleher, Philip, Buivydas, Andrius, de Waal, Paul P., van Rijswijck, Irma M.H., van Peij, Noël N.M.E., Mahony, Jennifer, and Van Sinderen, Douwe
- Abstract
•Active promoters in pNP40 and pUC11B conjugation clusters are identified.•Regulatory elements of said clusters include the conjugation-associated relaxases.•Relaxase expression of both systems appears to be autoregulated.•Tra20 may regulate pNP40 conjugation in an uncharacterized manner.
- Published
- 2024
- Full Text
- View/download PDF
13. Draft Genome Sequences of Two Geobacillus Species Strains, Isolated from Oil Wells and Surface Soil above Oil Pools
- Author
-
Kaunietis, Arnoldas, primary, de Jong, Anne, additional, Pranckutė, Raminta, additional, Buivydas, Andrius, additional, and Kuipers, Oscar P., additional
- Published
- 2016
- Full Text
- View/download PDF
14. Archaeal viruses multiply: temporal screening in a solar saltern
- Author
-
University of Helsinki, Department of Biosciences, University of Helsinki, Institute of Biotechnology, Atanasova, Nina S., Demina, Tatiana A., Buivydas, Andrius, Bamford, Dennis H., Oksanen, Hanna M., University of Helsinki, Department of Biosciences, University of Helsinki, Institute of Biotechnology, Atanasova, Nina S., Demina, Tatiana A., Buivydas, Andrius, Bamford, Dennis H., and Oksanen, Hanna M.
- Abstract
Hypersaline environments around the world are dominated by archaea and their viruses. To date, very little is known about these viruses and their interaction with the host strains when compared to bacterial and eukaryotic viruses. We performed the first culture-dependent temporal screening of haloarchaeal viruses and their hosts in the saltern of Samut Sakhon, Thailand, during two subsequent years (2009, 2010). Altogether we obtained 36 haloarchaeal virus isolates and 36 archaeal strains, significantly increasing the number of known archaeal virus isolates. Interestingly, the morphological distribution of our temporal isolates (head-tailed, pleomorphic, and icosahedral membrane-containing viruses) was similar to the outcome of our previous spatial survey supporting the observations of a global resemblance of halophilic microorganisms and their viruses. Myoviruses represented the most abundant virus morphotype with strikingly broad host ranges. The other viral morphotypes (siphoviruses, as well as pleomorphic and icosahedral internal membrane-containing viruses) were more host-specific. We also identified a group of Halorubrum strains highly susceptible to numerous different viruses (up to 26). This high virus sensitivity, the abundance of broad host range viruses, and the maintenance of infectivity over a period of one year suggest constant interplay of halophilic microorganisms and their viruses within an extreme environment.
- Published
- 2015
15. Lietuvos akademinio jaunimo migracija : studijų aplinkos įtaka sprendimams : mokslo studija
- Author
-
Ramanauskaitė, Egidija, Vaišnys, Juozas Rimvydas, Kairaitytė, Aušra, and Buivydas, Andrius
- Subjects
Lietuva--Emigracija ir imigracija ,Švietimas--Lietuva ,Lithuania--Emigration and immigration ,Education--Lithuania - Abstract
Mokslinėje studijoje pristatomi autorių atlikto moksleivių ir studentų migracijos procesų empirinio tyrimo rezultatai. Tyrimo duomenys atskleidė, kad studijų kokybė yra vienas aktualiausių veiksnių, skatinančių jaunimą rinktis studijuoti užsienio universitetuose. Nustatyta, jog universitetai ir studentai skirtingai supranta studijų kokybę, todėl svarbu išsiaiškinti studentų sampratą, kad sėkmingai vyktų universitetų ir studentų dialogas. Aptariamos studentų suvokiamos studijų kokybės dedamosios, jų studijų pasirinkimo principai. Analizuojama, kaip studentai lygina Lietuvos ir užsienio universitetų akademinio gyvenimo aplinką: studijų programas, dėstomus dalykus, dėstytojų darbą, universitetų administracijos bendravimą su studentais ir kt. Iškeliamos nepakankamo akademinio jaunimo domėjimosi realiais visuomenės procesais problemos, nemokėjimas sukaupti socialiniam gyvenimui reikalingų žinių. Remiantis tyrimo duomenimis, pateikiami studijų kokybės trikdžiai ir aprašomos šių trikdžių suvaldymo galimybės. Tyrimo išvados turėtų sudominti visus, kurie gilinasi į aktualius studijų pasirinkimo ir studijų kokybės klausimus. Scientific study presents the empirical research results of pupils and students migration processes. The research data revealed that the quality of education is one of the relevant factors encouraging young people to study in foreign universities. It was found that universities and students have different perceptions of study quality, so it is important to clarify the concept of study quality to successfully run dialogue between universities and students. The study discusses different components of study quality. Analyzing how students compare Lithuanian and foreign universities academic environment: study programs, subjects, teaching, university administrators relationship with students and etc. Study raises academic youths' lack of interest in problems concerning public process, inability to build the necessary knowledge for social life. The research data raises study quality disturbances and suggests their regaining possibilities. The study findings and recommendations should be interesting to all who are interested in choosing study and organizing study quality issues.
- Published
- 2013
16. Assessment of the activity of RND-type multidrug efflux pumps in using tetraphenylphosphonium ions
- Author
-
Daugelavičius, Rimantas, Buivydas, Andrius, Senčilo, Ana, Bamford, Dennis H., Department of Biochemistry and Biophysics, Vilnius University [Vilnius], Vytautas Magnus University - Vytauto Didziojo Universitetas (VDU), and University of Helsinki
- Subjects
RND-type efflux pumps ,Tetraphenylphosphonium ,Outer membrane permeability - Abstract
International audience; Multidrug resistance (MDR) pumps are one of the major causes of antibiotic resistance in . Thus, fast and reliable methods are needed to assay the efficiency of MDR pumps in these bacteria. In this study, it was demonstrated that a membrane voltage (Δψ) indicator tetraphenylphosphonium (TPP) in combination with the efflux pump inhibitor phenylalanyl-arginyl-β-naphthylamide can be used to monitor the activity of resistance-nodulation-cell division (RND)-type efflux pumps in . By controlling the outer membrane permeability and Δψ? electrochemical measurements of RND pump activity in real time were performed. It was demonstrated that the composition of the medium, the presence of nutrients and the level of aeration affect the efficiency of the TPP-extruding activity of , urging the standardisation of experimental conditions to obtain quantitative and comparative results.
- Published
- 2010
17. Antibiotikus išmetančių pompų veiklos escherichia coli ir pseudomonas aeruginosa ląstelėse tiesioginis vertinimas
- Author
-
Buivydas, Andrius and Daugelavičius, Rimantas
- Subjects
coli ,aeruginosa ,antibiotic resistance - Abstract
Multidrug resistance (MDR) pumps are one of the major causes of resistance in opportunistic pathogens, such as Pseudomonas aeruginosa. Consequently, fast and reliable methods are needed to assay the efficiency of MDR pumps in these bacteria. However, direct efflux pump functions’ real-time assessment methods are missing. Such assays would improve the evaluation of MDR efflux pump activities and the search for potential inhibitors. The assay for monitoring of MDR efflux pumps, employing voltage (Δψ) indicator tetraphenylphosphonium (TPP+) and TPP+-selective electrodes was developed. The assay was applied to evaluate the activity of tetracycline specific efflux pump TetA(B) in E. coli. Competitive inhibition of TetA(B) activity was demonstrated. Moreover, it was shown that tetracycline-specific efflux pump TetA(B) has higher selectivity for TPP+ than tetracycline. The designed method can be used for real-time monitoring of MDR efflux pumps in P. aeruginosa. The main factors influencing the activities of MDR efflux pumps were addressed: outer membrane permeability, Δψ, aeration, temperature and cell growth stage. It was also shown that TPP+ in combination with the pump inhibitor phenylalanyl-arginyl-β-naphtylamide (PAβN) can be used to monitor the activity of RND-type efflux pumps in P. aeruginosa. By controlling the outer membrane permeability and Δψ, the real-time measurements of the RND pump activity were performed. It was shown that PAβN depolarizes plasma membrane of the cell in the medium without any nutrients. However, under optimal growth conditions P. aeruginosa cells are able to recreate the outer membrane barrier covering the activities of MDR efflux pumps. Furthermore, it was shown that the activities of P. aeruginosa MDR efflux pumps diminish in lower than room temperature. Altogether, it was demonstrated that the activity of RND-type efflux pumps in P. aeruginosa is highly sensitive to incubation conditions such as the presence of nutrients, incubation medium, the level of aeration and temperature. Thus, it is of great importance to standardize the experimental conditions to obtain quantitative and comparative results.
- Published
- 2010
18. Real-time assessment of the activity of antibiotic efflux pumps in escherichia coli and pseudomonas aeruginosa
- Author
-
Buivydas, Andrius and Daugelavičius, Rimantas
- Subjects
coli ,aeruginosa ,antibiotic resistance - Abstract
Antibiotic resistance is one of the main factors causing difficulties in treatment of bacterial infections. Several mechanisms are known to be responsible for this resistance, including target alteration, enzymatic modification of antibiotics, low cell envelope permeability and active efflux of toxic compounds. The latter mechanism is considered to play a major role in bacterial antibiotic resistance. In this study a method for real-time efflux pump activity evaluation has been developed. Importantly, in contrast to other methods, neither radio-labeled nor toxic compounds are used in this method. Moreover, bacterial suspension is thermostated and aerated throughout the assay. Tetraphenylphosphonium (TPP+) ions and TPP+-selective electrodes were used to evaluate the activities of tetracycline-specific TetA(B) and multiple drug resistance pumps (MDR) in E. coli and P. aeruginosa, respectively. It was shown that TetA(B) can effectively expel not only tetracycline but also TPP+. Optimal conditions for evaluation of the activities of MDR efflux pumps in P. aeruginosa were determined. The developed method can be applied to study the interactions between the efflux pump inhibitors and their cellular targets. Moreover, this method can be applied to monitor the differences in efflux pumps’ activities among clinical isolates.
- Published
- 2010
19. Archaeal Viruses Multiply: Temporal Screening in a Solar Saltern
- Author
-
Atanasova, Nina, primary, Demina, Tatiana, additional, Buivydas, Andrius, additional, Bamford, Dennis, additional, and Oksanen, Hanna, additional
- Published
- 2015
- Full Text
- View/download PDF
20. Developing methods and computer tools for a systematic qualitative data analysis
- Author
-
Buivydas, Andrius, Ramanauskaitė, Egidija, and Vaišnys, Rimas J.
- Subjects
Socialiniai tyrimai ,Social surveys ,Computer systems ,Kompiuterių sistemos - Abstract
Straipsnyje pateikiamas sisteminės duomenų analizės metodas, grindžiamas dinaminių sistemų teorijos prieiga (žr. „Groups in Theory and Practice“, p. 23), kurį VDU Kultūros tyrimų centro tyrėjai taikė atvejo studijose. Metodas buvo išbandytas ir grupių lyginamajai analizei, dalyvaujant tyrėjams iš „CIVIS“ (Moldova), „Region“ (Rusija), CASD (Tatarstanas) tyrimų centrų, taip pat Daugpilio universiteto (Latvija) ir Galati „Dunarea de Jos“ universiteto (Rumunija).2 Straipsnyje pateikti pavyzdžiai iš Lietuvos hipių grupės duomenų analizės ir iš SAL projekte taikytos lyginamosios duomenų analizės. Autorių sukurtos sisteminės duomenų analizės pagrindinis principas – suformuoti tyrimui reikšmingas duomenų struktūras, kurios padėtų išsamiai aprašyti duomenis, taip pat palyginti dviejų ar daugiau grupių duomenis. Buvo suformuotos tiriamosios sistemos (individo arba grupės) būsenos, aplinkos ir saviraiškos kintamųjų ir verčių struktūros, kurios padėjo ieškoti priežastinių ryšių tarp minėtų kintamųjų. Sukurta kompiuterinė tekstinių duomenų analizės programa, kuri padeda tyrėjui greičiau ir tiksliau išrūšiuoti duomenis. Straipsnyje aprašytas duomenų paruošimo kompiuterinei analizei metodas: kaip tyrėjas turi sužymėti duomenis, kad kompiuteris „suprastų“ tyrėjo sumanymą. Straipsnio autoriai norėtų paskatinti tyrėjus pačius kurti kompiuterines programas, kurios gali padėti lengviau įgyvendinti jų individualius sumanymus. Computer tools for qualitative data analysis were developed by Vytautas Magnus University researchers for their case studies. The methods were also used for comparative analysis and tested when working together with researchers from the CIVIS (Moldova), Region (Russia) and CASD (Tatarstan) research centres as well as with researchers from Daugavpils University (Latvia), Dunarea de Jos University of Galati (Romania) and Vytautas Magnus University (Lithuania). Excerpts from the data analysis of the case study on Lithuanian hippies as well as from the SAL comparative analysis are presented in this article.
- Published
- 2010
21. Groups in theory and practice
- Author
-
Vaišnys, Rimas J., Buivydas, Andrius, and Ramanauskaitė, Egidija
- Subjects
Socialinės grupės ,Bendravimas ir mažosios socialinės grupės ,Communication in small social groups ,Social groups - Abstract
Vytauto Didžiojo universiteto tyrėjai analizuoja empirinių tyrimų ir teorijos sąveikos tobulinimo galimybes. Tradiciškai stebėjimams ir teorijoms keliami skirtingi uždaviniai. Autoriai siūlo metodą, padėsiantį šiuos uždavinius integruoti. Integruota tyrėjų veikla trunka gerokai ilgiau, nei galima tikėtis, nes stebėjimų ir teorijos sąveikos bei plėtros kryptis svarbu suderinti jau pirmuose bandymų etapuose, kai pritaikomumas vis dar gali būti modifikuotas. Šią ataskaitą sudaro trys skyriai. Pirmame skyriuje (parengtame J. Rimo Vaišnio) „Dinaminių sistemų prieigos pristatymas“ pateikiama dinaminių sistemų teorijos prieiga, t. y. kaip ją supranta fizikos mokslai ir, vis didėjančiu mastu, biologijos mokslai. Tai, kad šis teorinis požiūris prisidėjo prie problemų formulavimo ir sprendimo, aprėpdamas tiek disciplinų, suteikia daug motyvacijos jį taikyti tiriant subkultūras. Vienas pirmųjų teorijos įnašų į mokslo plėtrą yra rekomendacijos apie empirinės informacijos organizavimą, o šioje veikloje vienas pirmųjų žingsnių yra apibūdinti tiriamų objektų panašumus ir skirtumus. Pirmojo skyriaus pabaigoje pateikta iliustracija, kurioje naudojami faktiniai tyrimo duomenys, gauti projekto įgyvendinimo metu (p. 29). Kai tik visa informacija, gauta atliekant projekto tyrimus, bus tinkamai sutvarkyta, galima tikėtis sparčios pažangos, taikant šią metodiką. Antrasis skyrius (parengtas Andriaus Buivydo) „Mažų grupių modeliavimo galimybių pristatymas“ skirtas matematinio modeliavimo galimybėms... [toliau žr. visą tekstą] Vytautas Magnus University researchers report on their progress in melding empirical research with formal theoretical development. Two aspects of the experience warrant immediate comment. First such a melding leads to substantial modifications of how both empirical and theoretical work are carried out in practice in contrast to the more traditional approaches where observations and theory tend to follow their own distinct paths. Second such integrated activities are more time consuming than anticipated, because the need for quality control in observations and in theorising become evident even at the early stages of the endeavour when practices can still be modified. This report is in three sections. The first, Overview of the dynamical systems approach, by Rimas Vaišnys, presents an overview of the dynamical systems theory as it is understood in the physical sciences and, to an increasing extent, in the biological sciences. That this theoretical approach has contributed to phrasing and solving problems in such a range of disciplines provides the motivation to apply it in studying subcultures. One of the first contributions that a theory can make to a scientific undertaking is to provide guidance in organising empirical informatikon and, in this activity, one of the first steps is to characterise similarities and differences among the objects being investigated. This section ends with an illustration using actual field data obtained during the project. Once all the... [to full text]
- Published
- 2010
22. Grupė kaip dinaminė sistema : nuo ko pradėti?
- Author
-
Buivydas, Andrius and Vaišnys, J. Rimas
- Subjects
Socialinės grupės ,Subkultūra ,Subculture ,Social groups - Abstract
Siūlomas grupės aprašymas padeda tiriamą grupę vienareikšmiškai išskirti iš grupių rinkinio. Naudojama dinaminių sistemų prieiga padeda natūraliai susieti empirinį grupės aprašymą su grupę apibūdinančio modelio aprašymu. Antroje straipsnio dalyje plačiau nagrinėjamas ryšys tarp modeliavimo proceso ir empirinės etnografinės medžiagos rinkimo. This article outlines the nature of the observations and modelling which are necessary to obtain a well defined characterisation of a subcultural group. The general rule indicates that, for a useful characterisation of a group, it is necessary to describe not only its state but also the way the group interacts with its environment, i.e., the rest of the society. To understand the dynamics of a group it is necessary to study these characterisations at more than one instance. With regard to the first point, it makes a significant difference what variables to consider when describing the state of a group. On the one hand, the variables considered by the press and other actors in the environment of the group may not all be important; on t he other hand, the same variables may not be sufficient to characterise either the group or its interaction with the environment. The second point reveals what is necessary to begin defining the functions that allow a causal explanation of the behaviour of a group. Only after constructing a complete – even if approximate – model of a group can a researcher decide if both the observations and the theorizing are on the right track.
- Published
- 2009
23. Grupių elgesio modeliavimo link : naujieji pagonys
- Author
-
Ramanauskaitė, Egidija, Buivydas, Andrius, and Vaišnys, J. Rimas
- Subjects
Paganism ,Socialinės grupės ,Subkultūra ,Subculture ,Pagonybė ,Social groups - Abstract
Straipsnio paskirtis – naujųjų pagonių grupės elgesio analizė, taikant grupės tyrimui dinaminių sistemų teorijos prieigą. Grupės elgesys tokioje prieigoje tyrinėjamas atskirai aptariant kiekvieno jos nario elgesį ir jį veikiančias aplinkas. Grupės nario aplinką sudaro kiti grupės nariai ir jam aktuali išorinė aplinka. Renkant ir sisteminant duomenis daroma prielaida, jog grupės nario būsena tam tikru laiko momentu yra susijusi su ankstesne jo būsena ir jį veikiančia aplinka. Ši būsena lemia grupės nario saviraišką. Straipsnio uždaviniai yra dvejopi: 1) autorius domina konkrečios naujųjų pagonių grupės elgesio analizė; 2) ieškoma universalių metodų, padedančių atskleisti analizuojamos grupės reiškinį. Straipsnyje pristatomas pagonių grupės empirinio tyrimo fragmentas, kurio išsami analizė leidžia įžvelgti reikšmingus grupės narių elgesio ypatumus. Pateikiamos lentelės ir paveikslėliai padeda aprėpti gausią informaciją, nurodančią grupės nario ryšius su jo aplinkomis. In this article we describe the properties and behaviour of a small group of Lithuanian neo- Pagans. The information was obtained by both observations and by a series of in-depth interviews, the latter organized in accord with a questionnaire constructed to elucidate group values and important interactions with the group environment. The information was collected and organized as guided by a dynamical systems approach, where each individual of the group is treated as a system whose total environment consists of all the other individuals and also the more general environment common to all the group members. This approach naturally groups the interactions between the chosen system and its environment into system inputs and system outputs which, however, are strongly modified by the system state. In turn changes in the system state are produced by system inputs which, in turn, may come about due to earlier system outputs directed to the environment. Thus feedback loops which either enhance or suppress selected behaviours can and do arise. The article presents a detailed description of the behaviour and properties of a selected group member in relation to her/his (so stated to protect the identity of the respondent) environment (the other group members and the more general overall influences) in terms of values and collections of values, i.e., variables. In the systems context, values are descriptions of behaviour which have been characterised specifically and unambiguously... [to full text]
- Published
- 2009
24. Assessment of the activity of RND-type multidrug efflux pumps in Pseudomonas aeruginosa using tetraphenylphosphonium ions
- Author
-
Daugelavičius, Rimantas, Buivydas, Andrius, Senčilo, Ana, and Bamford, Dennis H.
- Published
- 2010
- Full Text
- View/download PDF
25. Real-time assessment of the activity of antibiotic efflux pumps in escherichia coli and pseudomonas aeruginosa
- Author
-
Čitavičius, Donaldas, Mildažienė, Vida, Sužiedėlienė, Edita, Bagdonienė, Lida, Šatkauskas, Saulius, Pavilonis, Alvydas, Meškys, Rolandas, Daugelavičius, Rimantas, Bamford, Dennis, Vilnius University, Buivydas, Andrius, Čitavičius, Donaldas, Mildažienė, Vida, Sužiedėlienė, Edita, Bagdonienė, Lida, Šatkauskas, Saulius, Pavilonis, Alvydas, Meškys, Rolandas, Daugelavičius, Rimantas, Bamford, Dennis, Vilnius University, and Buivydas, Andrius
- Abstract
Multidrug resistance (MDR) pumps are one of the major causes of resistance in opportunistic pathogens, such as Pseudomonas aeruginosa. Consequently, fast and reliable methods are needed to assay the efficiency of MDR pumps in these bacteria. However, direct efflux pump functions’ real-time assessment methods are missing. Such assays would improve the evaluation of MDR efflux pump activities and the search for potential inhibitors. The assay for monitoring of MDR efflux pumps, employing voltage (Δψ) indicator tetraphenylphosphonium (TPP+) and TPP+-selective electrodes was developed. The assay was applied to evaluate the activity of tetracycline specific efflux pump TetA(B) in E. coli. Competitive inhibition of TetA(B) activity was demonstrated. Moreover, it was shown that tetracycline-specific efflux pump TetA(B) has higher selectivity for TPP+ than tetracycline. The designed method can be used for real-time monitoring of MDR efflux pumps in P. aeruginosa. The main factors influencing the activities of MDR efflux pumps were addressed: outer membrane permeability, Δψ, aeration, temperature and cell growth stage. It was also shown that TPP+ in combination with the pump inhibitor phenylalanyl-arginyl-β-naphtylamide (PAβN) can be used to monitor the activity of RND-type efflux pumps in P. aeruginosa. By controlling the outer membrane permeability and Δψ, the real-time measurements of the RND pump activity were performed. It was shown that PAβN depolarizes plasma membrane of the... [to full text], Atsparumas antibiotikams yra viena didžiausių kliūčių, gydant bakterijų sukeltas infekcijas. Bakterijų atsparumą antibiotikams lemia kelių rūšių mechanizmai: taikinio pakeitimas, antibiotikų ardymas fermentais, mažas ląstelės apvalkalėlio laidumas bei aktyvus kenksmingų medžiagų išmetimas iš ląstelės. Pastarojo mechanizmo indėlis yra pats didžiausias. Šiame darbe buvo sukurtas metodas, leidžiantis tiesiogiai vertinti antibiotikus išmetančių pompų veiklą bei efektyvumą, nenaudojant radioaktyvių ar toksiškų junginių. Labai svarbus šio metodo privalumas yra tai, kad tiriama bakterijų suspensija yra aeruojama pastovioje, kontroliuojamoje temperatūroje. E. coli atsparumą tetraciklinui [TetA(B)] ir P. aeruginosa daugiavaistį atsparumą lemiančių pompų tiesioginiam aktyvumo vertinimui buvo pritaikyti tetrafenilfosfonio (TPP+) jonai ir jiems atrankūs elektrodai. Buvo atrinktos sąlygos P. aeruginosa daugiavaistį atsparumą lemiančių pompų veiklos registravimui. Taip pat buvo nustatyta, kad TetA(B) kaip substratą gali naudoti ne tik tetracikliną, bet ir TPP+. Naudojantis sukurtu metodu galima greitai ir efektyviai įvertinti pompų slopiklių efektyvumą bei jų sąveiką su ląstelėmis. Šis metodas taip pat gali būti naudojamas, siekiant nustatyti antibiotikus išmetančių pompų veiklos skirtumus klinikiniuose bakterijų izoliatuose.
- Published
- 2010
26. Clinical isolates ofPseudomonas aeruginosafrom superficial skin infections have different physiological patterns
- Author
-
Buivydas, Andrius, primary, Pasanen, Tanja, additional, Senčilo, Ana, additional, Daugelavičius, Rimantas, additional, Vaara, Martti, additional, and Bamford, Dennis H., additional
- Published
- 2013
- Full Text
- View/download PDF
27. Increasing the success rate of lantibiotic drug discovery by Synthetic Biology
- Author
-
Montalbán-López, Manuel, primary, Zhou, Liang, additional, Buivydas, Andrius, additional, van Heel, Auke J, additional, and Kuipers, Oscar P, additional
- Published
- 2012
- Full Text
- View/download PDF
28. Clinical isolates of Pseudomonas aeruginosa from superficial skin infections have different physiological patterns.
- Author
-
Buivydas, Andrius, Pasanen, Tanja, Senčilo, Ana, Daugelavičius, Rimantas, Vaara, Martti, and Bamford, Dennis H.
- Subjects
- *
PSEUDOMONAS aeruginosa , *SKIN disease genetics , *DRUG resistance in microorganisms , *SEPSIS , *PHENOTYPES , *MICROBIAL physiology , *PHYSIOLOGY , *PATIENTS ,LEG ulcers - Abstract
Pseudomonas aeruginosa are known to have a wide physiological potential allowing them to constantly populate diverse environments leading to severe infections of humans such as septicemia, leg ulcers, and burn wounds. We set out to probe physiological characteristics of P. aeruginosa isolates from diabetic leg ulcers collected from Helsinki metropolitan area. A total of 61 clinical isolates were obtained. Detailed phenotypic (physiological) characteristics [outer membrane ( OM) permeability, membrane voltage, and activity of multidrug resistance pumps] were determined in several growth phases leading to the division of the analyzed set of P. aeruginosa strains into five distinct clusters including cells with similar physiological properties. In addition, their antibiotic resistance patterns and genetic heterogeneity were determined. Multiple isolates from the same patient were genetically very closely related and belonged to the same phenotypic cluster. However, genetically close isolates from different patients expressed very different phenotypic properties. The characteristics of infected patients seem to determine the growth environments for microorganisms that adapt by changing their physiological and/or genetic properties. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
29. Development of multilayered artificial urethra graft for urethroplasty.
- Author
-
Barasa P, Simoliunas E, Grybas A, Zilinskaite-Tamasauske R, Dasevicius D, Alksne M, Rinkunaite I, Buivydas A, Baltrukonyte E, Tamulyte R, Megur A, Verkauskas G, Baltriukiene D, and Bukelskiene V
- Abstract
To enhance the treatment of patients' urethral defects, such as strictures and hypospadias, we investigated the potential of using artificial urethral tissue. Our study aimed to generate this tissue and assess its effectiveness in a rabbit model. Two types of bioprinted grafts, based on methacrylated gelatin-silk fibroin (GelMA-SF) hydrogels, were produced: acellular, as well as loaded with autologous rabbit stem cells. Rabbit adipose stem cells (RASC) were differentiated toward smooth muscle in the GelMA-SF hydrogel, while rabbit buccal mucosa stem cells (RBMC), differentiated toward the epithelium, were seeded on its surface, forming two layers of the cell-laden tissue. The constructs were then reinforced with polycaprolactone-polylactic acid meshes to create implantable multilayered artificial urethral grafts. In vivo experiments showed that the cell-laden tissue integrated into the urethra with less fibrosis and inflammation compared to its acellular counterpart. Staining to trace the implanted cells confirmed integration into the host organism 3 months postsurgery., (© 2024 Wiley Periodicals LLC.)
- Published
- 2024
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.