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Probing the dNTP Binding Region of <em>Bacillus subtilis</em>: DNA Polymerase III with Site-Directed Inhibitors: A DissertationButler, Michelle Marie 13 March 1992 (has links)
6-(p-Hydroxyphenylhydrazino) uracil (H2-HPUra) is a selective and potent inhibitor of the replication-specific DNA polymerase III (pol III) of Gram+ bacteria such as Bacillus subtilis. Although a pyrimidine, H2-HPUra derives its inhibitory activity from its specific capacity to mimic the purine nucleotide, dGTP. The project described in this thesis dissertation involves the use of H2-HPUra-like inhibitors to probe the structure and function of the pol III active site. It consists of two separate problems which are summarized below.
Production of a potent bona fide dGTP form of inhibitor. A method was devised to successfully convert the H2-HPUra inhibitor prototype to a bona fide purine, using N2-benzyl guanine as the basis. Structure-activity relationships of benzyl guanines carrying a variety of substituents on the aryl ring identified N2-(3,4-dichlorobenzyl) guanine (DCBG) as a compound equivalent to H2-HPUra with respect to potency and inhibitor mechanism. DCBdGTP, the 2'-deoxyribonucleoside 5'-triphosphate form of DCBG, was synthesized and characterized with respect to its action on wild-type and mutant forms of pol III. DCBdGTP acted on pol III by the characteristic inhibitor mechanism and formally occupied the dNTP binding site with a fit which permitted its polymerization. The latter experiment identified the site for the binding of the inhibitor's aryl moiety as a distinct site located at a distance of approximately 6-7 Å from the base-paired 2-NH group of a bound dGTP.
Attempt to covalently label amino acid residue 1175, a putative participant in inhibitor binding. Azp-12, a point mutation of serine 1175, yields a form of pol III whose inhibitior sensitivity varies specifically as a function of the composition of the para substituent of the inhibitor's aryl ring. On the basis of the latter behavior, residue 1175 was hypothesized to be a residue directly involved in the binding of the inhibitor's aryl moiety. To test this hypothesis, residue 1175 was specifically mutated to either cysteine or lysine, each of which presents a side chain amenable to covalent bond formation with appropriately reactive inhibitor forms. Of the two mutant pol III forms, only the cysteine form (pol III-cys) was catalytically active. The kinetic properties and inhibitor sensitivity profile of pol III-cys identified it as a target suitable for potentially irreversible inhibitor forms containing the following groups in the meta position of the aryl ring: -CH2Br, -CH2C1, and -CH2SH. None of the several inhibitors tested selectively or irreversibly inactivated pol III-cys. Possible bases for the failure of this group of inhibitors and for the redesign of more useful covalently reactive inhibitor forms are considered.
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Comportamento alimentar do camar?o marinho farfantenaeus subtilis em condi??es laboratoriaisSilva, Priscila Fernandes 30 March 2009 (has links)
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Previous issue date: 2009-03-30 / Shrimp culture represents an important activity to brazilian economy. The northeastern region has presented high levels of production because of its climatic conditions. An important factor for the activity?s major development is related to the introduction of the species Litopenaeus vannamei. The use of an exotic species can disturb the ecosystem. In the last decades, L. vannamei has been the only species cultivated in Brazilian farms, there not being an alternative species for shrimp culture. So, there is an urgent need to developing new studies with the native species, which might represent an alternative concerning shrimp production, with emphasis on Farfantepenaeus subtilis. Another important aspect related to the activity is feeding management, once it is quite usual that feed offer on the pond does not take into account either the species? physiology and behavior or the influence of environmental variables, such as light cycle and substrate. That knowledge may optimize management and so reduce the impact of effluents in the environment. This study?s objective was characterizing feeding behavior of F. subtilis in laboratory. For that, an ethogram was developed, using 20 wild animals which were observed through ad libitum and all occurrences methods. Two experiments were developed in order to register feeding behavior on different substrates, along 15 days, each. In the first experiment, 40 animals were distributed in eight aquaria, half being observed during the light phase of the 24 hour cycle and the other half in the dark phase, both in halimeda substrate. In the second experiment, 20 animals were distributed in four aquaria, under similar conditions as the previous ones, but in sand substrate. In both experiments, animals were observed respectively one, four, seven and ten hours after the beginning of the phase, for light phase, for the dark phase, in ten minute observation windows, before and immediately after feed offer. The following behaviors were registered: feed ingestion, ingestion of other items, inactivity, exploration, vertical exploration, swimming, crawling, digging, burrowing, and moving by the animals. Observation windows after feed offer also included latency to reach the tray and to ingest feed. Nineteen behaviors were described for the species. F. subtilis presented more behavioral activities in halimeda substrate even in the light phase, while burrowing was predominant in sand substrate. In both substrates, moving, crawling and exploration were more frequent after feed offer, but inactivity and burrowing were more frequent before that. Feed ingestion was more frequent in halimeda, both in light and dark phases. Weight gain was also more prominent in that substrate. In sand substrtate, ingestion was more frequent in the dark phase, which suggests that higher granulometry facilitates feed ingestion in F. subtilis juveniles. Our results demonstrate the importance of studies for the better knowledge of the species, specially its response to environmental stimuli, in order to improve animal management / A carcinicultura ? uma atividade de grande import?ncia econ?mica no Brasil. Um fator que contribuiu para o crescimento da atividade foi a introdu??o da esp?cie Litopenaeus vannamei. A utiliza??o de uma esp?cie ex?tica pode causar danos ao ecossistema nativo e atualmente L. vannamei ? a ?nica esp?cie cultivada no Brasil, n?o havendo uma alternativa para o setor. Da? a necessidade de estudos com esp?cies nativas que possam representar outra via para a produ??o, em particular Farfantepenaeus subtilis. O conhecimento sobre o comportamento e fisiologia da esp?cie e sobre a influ?ncia das caracter?sticas do ambiente, como o ciclo de luz e substrato, sobre a ingest?o, pode otimizar o manejo e minimizar o impacto do despejo de efluentes no meio ambiente. Assim, esse estudo objetiva caracterizar o comportamento alimentar de F. subtilis ao longo do ciclo de luz em diferentes substratos sob condi??es laboratoriais. Para isso foi elaborado um etograma utilizando 20 animais trazidos da natureza, e observados pelos m?todos ad libitum e Todas as Ocorr?ncias. Para observa??o do comportamento alimentar dois experimentos foram realizados em diferentes substratos, com dura??o de 15 dias cont?nuos cada. No primeiro experimento 40 animais foram distribu?dos em oito aqu?rios, quatro na fase de claro e quatro na fase de escuro, com substrato de conchas de ostras trituradas (halimeda). No segundo experimento 20 animais foram distribu?dos em quatro aqu?rios, dois na fase de claro e dois na fase de escuro, com substrato de areia. Em ambos os experimentos os animais foram observados na fase de claro nos hor?rios 7h, 10h, 13h e 16h (1, 4, 7, 10) e nos hor?rios equivalentes na fase de escuro19h, 22h, 1h e 4h (1, 4, 7, 10), em janelas de 10 minutos antes e imediatamente ap?s a oferta da ra??o. Os comportamentos registrados foram: ingest?o do item ofertado, ingest?o do item que n?o o ofertado, parado, explora??o, explora??o vertical, nata??o, rastejamento, cavar, enterramento, limpeza e o deslocamento dos animais. Ap?s a oferta do alimento as lat?ncias de chegada a bandeja e de consumo do alimento foram registradas. Ao todo 19 comportamentos foram descritos para a esp?cie. F. subtilis apresentou uma maior diversidade de comportamentos na halimeda, mesmo na fase de claro, enquanto que na areia o enterramento predominou. Nos dois substratos o deslocamento, rastejamento e explora??o foram mais freq?entes ap?s a oferta do alimento, enquanto o parado e o enterramento foram mais frequentes antes. A ingest?o da ra??o foi maior no substrato de halimeda, n?o diferindo entre as fases de claro e escuro, o ganho de peso dos animais tamb?m foi maior nesse substrato. Na areia a ingest?o foi mais freq?ente na fase de escuro, o que sugere que substratos de maior granulometria favorecem a ingest?o do alimento em juvenis de F. subtilis. Nossos resultados demonstram a import?ncia do conhecimento da esp?cie e de sua resposta aos est?mulos do ambiente, como subs?dio para o desenvolvimento de estrat?gias de manejo eficientes
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Prebióticos e probióticos dietéticos, desempenho e higidez de juvenis de pacu Piaractus mesopotamicus (Holmberg, 1887) / Dietary prebiotics and probiotics, performance and health of pacu juvenile (Piaractus mesopotamicus (Holmberg, 1887)Brunno da Silva Cerozi 22 June 2012 (has links)
O aumento populacional e a elevação no consumo de alimentos tem aumentado a necessidade de intensificação da aquicultura objetivando maiores produtividades para atendimento à elevação na demanda. Consequentemente, aumentam as chances de ocorrência de surtos epizoóticos dentro dos sistemas de produção, devido ao maior estresse imposto aos animais densidade elevada, manejo constante, transporte, baixa qualidade da água, etc. Alterações no estado fisiológico dos animais fazem com que seu sistema imunológico não consiga combater agentes inócuos em situações normais, mas que se tornam patogênicos nos casos de imunodepressão, levando a grandes perdas econômicas, seja com mão de obra, mortandade, medicamentos, etc. Assim, este estudo avaliou o efeito da administração individual ou conjunta de -glucano e Bacillus subtilis na dieta de juvenis de pacu, Piaractus mesopotamicus. Em um primeiro ensaio, quantidades crescentes de -glucano (60; 120; 180; 240 e 300 mg kg-1 de ração) e de B. subtilis (109 UFC g-1 de B. subtilis; 0,025%, 0,050%, 0,075%, 0,100%, 0,125%) foram adicionados a uma dieta basal extrudada (32% de proteína bruta PB; 3200 kcal kg-1 de energia digestível ED) e administrados a juvenis de pacu (8,91 ± 0,30 g) até a saciedade aparente por 75 dias, em um delineamento inteiramente aleatorizado. Ao final do período experimental, os animais foram anestesiados, pesados, submetidos à coleta de sangue e tecidos, para determinação do ganho de peso, conversão alimentar, taxa de crescimento específico, proteínas totais, albumina e globulina séricas, índice albumina:globulina (A:G), atividade da lisozima sérica, explosão respiratória de leucócitos e morfometria intestinais. Em um segundo ensaio conduzido nas mesmas condições ambientais, juvenis de pacu (2,0 ± 0,1 g; 15 peixes/aquário) foram alimentados por 59 dias com rações suplementadas pelos aditivos em questão, mais um grupo controle: -glucano de levedura 240 mg kg-1 de ração; B. subtilis comercial (109 UFC B. subtilis g-1) 0,100% de inclusão; tratamento simbiótico 240 mg de -glucano kg-1 + 0,100% de B. subtilis. Ao final do período experimental os peixes foram amostrados para determinação dos mesmos parâmetros anteriormente descritos. A inclusão dos níveis de -glucano e de Bacillus subtilis na dieta não influenciou o desempenho (P>0,05) de juvenis de pacu, mas peixes alimentados com a dieta contendo o B. subtilis consumiram mais ração (P<0,05). Não houve alterações nos parâmetros de morfologia intestinal (P>0,05), nem nos valores de explosão respiratória, atividade de lisozima, proteínas totais séricas e globulinas séricas. Quando os dois imunoestimulantes foram adicionados às dietas em combinação, também não foi observado efeito sobre os parâmetros de desempenho, explosão respiratória e atividade de lisozima, mas as proteinas totais séricas e as globulinas séricas foram positivamente influenciadas pelos tratamentos (P<0,05). As alturas de microvilosidades da porção cranial do intestino dos pacus alimentados com o tratamento simbiótico (-glucano + B. subtilis) foram maiores se comparadas ao grupo controle (P<0,05). Apesar de algumas respostas terem indicado efeito positivo sobre alguns parâmetros imunológicos e morfologia intestinal de pacus alimentados por uma combinação de -glucano + B. subtilis, não houve clara evidência que a administração simbiótica é superior à administração individual de cada imunoestimulante. / Stimulation of immune response by dietary supplements has already been proven effective in aquaculture. This work evaluates effects of dietary supplementation with the prebiotic -glucan, the probiotic Bacillus subtilis and their synbiotic combination on growth performance, immune responses, and intestinal morphology of pacu Piaractus mesopotamicus. In a first trial, a basal diet (32% crude protein; 3200 kcal kg-1) was supplemented with either -glucan (60; 120; 180; 240 e 300 mg kg-1) and B. subtilis (109 UFC g-1 of B. subtilis; 0.025%, 0.050%, 0.075%, 0.100%, 0.125%) levels and fed to groups of juvenile pacu (eight fish; 8.91 ± 0.3 g) stocked in 33 glass aquariums (70 L) for 75 days, setting up a totally randomized design trial (n=3). Fish were then weighed and had their blood drawn for determination of leucocytes respiratory burst activity, serum lysozyme activity and serum immunoglobulin concentration; intestinal tissue was sampled from two fish from each unit for micromorphology analysis. The inclusion of -glucan and Bacillus subtilis in the diet did not affect growth (P>0.05) of pacu juvenile, but fish fed diet containing levels of B. subtilis showed higher feed consumption (P<0.05). Intestinal morphology, respiratory burst activity, lysozyme activity, total serum proteins and total globulins were not affected in either inclusion of -glucan and Bacillus subtilis (P>0.05). In a second trial, a basal diet (34% crude protein; 3400 kcal kg-1) was supplemented with either -glucan (240 mg kg-1), B. subtilis (0.1 %) and -glucan + B. subtilis mix and fed to groups of juvenile pacu (15 fish; 2.0 ± 0.1 g) stocked in 16 glass aquariums (70 L) for 59 days, setting up a totally randomized design trial (n=4). Fish fed diets supplemented with -glucan + B. subtilis mix presented better growth rate, but it was not significantly different from other feeding groups. Serum total proteins and serum globulins (serum total proteins serum albumin) were affected by dietary supplements (P < 0.05); fish receiving the synbiotic treatment had higher serum globulin contents, but respiratory burst and lysozyme activity were not significantly affected. Dietary synbiotic mix altered the micromorphology of anterior intestine (P < 0.05), but the same effect was not observed in the mid and posterior intestines (P > 0.05). Dietary -glucan + B. subtilis synbiotic mix affected the intestinal ultrastructure of pacu, improved responses of immune system but did not significantly affect growth rate.
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Avaliação da esterilização de filme de polietileno com peroxido de hidrogenio e radiação ultravioleta / Sterilization evaluation of low density polyethylene film with hydrogen peroxide and ultraviolet radiationCardoso, Claudio Fernandes 04 November 2007 (has links)
Orientador: Jose de Assis Fonseca Faria / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T11:53:49Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007 / Resumo: O objetivo deste trabalho consistiu no processamento e avaliação de desempenho de um sistema asséptico piloto para filme de polietileno de baixa densidade (PEBD). Através da metodologia de planejamento experimental fatorial foram feitas variações de tempo de contato, temperatura do banho e concentração da solução esterilizante, bem como a variação do tempo de exposição à radiação ultravioleta (UVC). Estas variações tiveram por finalidade promover de 4 a 6 reduções decimais na população inicial de esporos de Bacillus subtilis var. globigii ATCC9372, em um curto espaço de tempo, gerando o menor residual do esterilizante em água envasada. Foram inoculados uniformemente 100µL do microrganismo teste em uma superfície de 16cm2. Testou-se como agente de esterilização química, o peróxido de hidrogênio (H2O2) e, como agente físico, a radiação UVC, sendo o primeiro aplicado na forma de banho de imersão e o segundo, por uma exposição a 2,5cm de distância do filme de PEBD logo após o banho de imersão. O sistema utilizado constituiu em uma envasadora automática e um protótipo com um tanque em aço inoxidável, desenvolvido especialmente para este tipo de teste. O H2O2 e a radiação UVC apresentaram ação esporicida significativa. O H2O2 demonstrou ação esporicida entre as concentrações de 18 e 35%, em um intervalo de temperatura de 46 a 70ºC, promovendo de 3 a 7 reduções decimais de Bacillus subtilis. A concentração de 20% de H2O2 não conferiu sabor estranho à água mineral envasada em embalagens de PEBD sanificadas, não diferindo, significativamente (p<0,05), do padrão. O residual de H2O2 das superfícies-teste sanificadas com soluções contendo de 18 a 35% de H2O2 foi superior a 0,5mg/L, nível máximo permitido pela FDA presente em água envasada sob as condições de produção. Os dados obtidos forneceram dois modelos matemáticos quadráticos, representativos da ação do H2O2 e radiação UVC, em função do tempo e da temperatura, sobre esporos de B. subtilis. Tais modelos, com R2 de 0,9349 para os tratamentos sem radiação UVC, e R2 de 0,9763 para os tratamentos com radiação UVC, limitaram-se a uma concentração de 35% de H2O2 e tempo máximo de exposição à radiação UVC de 8s. Superfícies-teste sanificadas com soluções de 28% de H2O2 a 60ºC, por 8s sem exposição à radiação UVC apresentaram 4 ciclos de redução decimal. Para as mesmas condições, porém com exposição à radiação UVC por 8s, este valor elevou-se para 7, demonstrando a existência do sinergismo entre a associação destes dois agentes. O sistema de esterilização testado apresentou desempenho satisfatório, podendo ser perfeitamente utilizado por indústrias de pequeno e médio porte na esterilização de filmes plásticos, sendo capaz de promover até 7 reduções decimais na população de esporos bacterianos / Abstract: The aim of this research consisted in the processing and performance evaluation of an aseptic pilot system for Low Density Polyethylene film (LDPE). Through the screening design methodology, variations of contact time, bath temperature, sanificant concentration and exposition time variation of ultraviolet radiation (UVC) was made. Such variations had as purpose to promote from 4 to 6 decimal reductions in the Bacillus subtilis var. globigii ATCC9372 spores, when applied to the LDPE film surface, in a short time, generating the minor residual of the sanificant in the plastic surface. Was evaluated as chemical agent, the hydrogen peroxide (H2O2) and as physical agent, UVC radiation, being the first one applied as immersion bath and the second one as an exposition after the immersion bath, with 2,5cm of distance of the PEBD film. The system used was constituted in an automatic filling machine and an equipment with a stainless steel tank, especially developed for this type of test. H2O2 showed sporicidal action in from 18 to 35%, in temperatures of 46 to 70ºC, causing from 3 to 7 decimal reductions. The H2O2 20% did not confer off-taste in mineral water used as filling product, as well no significant difference from the standard was observed (p<0,05). The hydrogen peroxide residual surface-test after sanitation with 18 to 35% H2O2 was higher than 0,5mg/L. However, the use of hot air knives or roller pressers after the immersion bath will be able to diminish this residual. The quadratic model, with R2 of 0,9349 for the treatments without UVC radiation and R2 of 0,9763 for the treatments with UVC radiation are restricted to 35% H2O2 and UVC maximum exposition time of 8s. Surface-test treated with 28% H2O2 / 60ºC / 8s without UVC radiation exposition had presented 4 decimal reduction. In the same conditions, however with UVC radiation exposition (8s), this value was raised for 7, demonstrating the existence of synergism between these two agents. The sanification system tested showed satisfactory performance, effective to be used in small and medium industries, being capable to promote up to 7 decimal reductions in spores population / Mestrado / Mestre em Tecnologia de Alimentos
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Uso de biocontroladores anti camping off en material orgánico bioprocesado para la producción de plantines de tomate.Molina Galleguillos, Andrea Pass January 2007 (has links)
La presente investigación se realizó con el fin de evaluar el uso de biocontroladores en la prevención de patógenos causantes de camping off y en el desarrollo de plantines de tomate, aplicados en un sustrato obtenido de material orgánico bioprocesado.
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Produção e aplicação de bioemulsificante isolado de Bacillus subtilis UCP 0146 por fermentação submersa em manipueiraMaia, Patricia Cristina de Veras Souza 29 June 2017 (has links)
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Previous issue date: 2017-06-29 / Biosurfactants are tensioactive compounds produced by bacteria, yeasts and filamentous
fungi, which have come in the molecule a hydrophobic and other hydrophilic portion, with
potential to reduce water surface tension and liquid emulsion with two phases, called
Bioemulsifiers. The bioemulsifiers presented potential of application in several industrial
areas such as: food, agricultural, pharmaceutical and petrochemical, their characteristics of
biodegradability, non-toxic and possibility of production from renewable substrates. In this
sense, studies carried out with Bacillus subtilis UCP 0146, investigating a bioemulsifier
production, using as substrate the agroindustrial effluent (manipueira). Cultivation was
carried out in Erlenmeyer flasks containing 75 mL (100%) of the production medium
(manimetry) according to the 23 factorial scale, with 5% inoculum at a concentration of 108
cells / mL, incubated at 30ºC under agitation of 150 rpm for 72h, being evaluated the
bioemulsifier produced in the cell free metabolic liquid, the emulsification inde (IE24). As the
good, the size of the emulsion droplets, stability to pH, NaCl and temperature. The results
showed that the emulsifier had a 95.2% emulsification index with the engine burned oil in the
best planning condition, showing a stable emulsion formation at all temperatures and a better
response at the temperature of 70ºC (96.0%). Regarding pH was observed in assay 2, an
(IE24) of 91.6% relative to salinity or assay 4 represented 92.0%. In addition, no dispersion
test showed displacement of 85.3 cm of the oil and the discoloration of methylene blue in
aqueous solution, obtained the result of 62.2% removal. The Bacillus subtilis demonstrated
the ability to produce bioemulsifiers using a metabolic conversion of the agroindustrial
residue, making the bioprocessing economical and great potential in the biotechnological
application. / Os Biossurfactantes são compostos tensoativos produzidos por bactérias, leveduras e fungos filamentosos, que apresentam na molécula uma porção hidrofóbica e outra hidrofílica, com potencial de redução da tensão superficial da água e ou de emulsificar líquidos com duas fases, os que apresentam essa última característica são denominados de bioemulsificantes. Apresentam potenciais de aplicação em varias áreas industriais como: alimentícia, agrícola, farmacêutica e petroquímica, devido a suas características de biodegradábilidade, não toxicidade e possibilidade de produção a partir de substratos renováveis. Neste trabalho, estudos foram realizados com Bacillus subtilis UCP 0146, investigando a produção de bioemulsificante, empregando como substrato o efluente agroindustrial (manipueira). O cultivo foi realizado em frascos de Erlenmeyers de 250 ml contendo 75 mL (100%) do meio de produção (manipueira) de acordo com planejamento fatorial completo 23, teve como variável independente o volume do inóculo, temperatura e agitação e como variável resposta o índice de emulsificação (IE24), com 5% de inóculo com concentração de 108 cel /mL, incubado a 30ºC, sob agitação de 150 rpm por 72h. Foi avaliado o bioemulsificante produzido no líquido metabólico livre de células, a fins da dosagem índice de emulsificação (IE24). As características do bioemulsificante avaliadas foram tamanho das gotas de emulsão, estabilidade frente a variações de pH, concentração de NaCl e temperatura. Os resultados mostraram que o bioemulsificante apresentou índice de emulsificação de 95,2% para óleo queimado de motor na melhor condição do planejamento (inóculo 9% (v/v), 25°C e 100rpm), apresentando formação de emulsão estável em relação ao IE24 em todas as temperaturas testadas, mas a melhor resposta foi com a temperatura de 70ºC (96.0%). Em relação ao pH, foi observado um IE24h de 91,6% e em relação a salinidade apresentou 92.0%. No teste de dispersão do deslocamento obteve o valor de 85,38 cm². Quanto ao potencial de adsorção do corante catiônico azul de metileno removeu 62,2% após 12h, como também a remoção de 94,4% do óleo queimado de motor impregnado em solo arenoso. O Bacillus subtilis apresentou habilidade de produzir bioemulsificante utilizando a conversão metabólica do resíduo agroindustrial, tornando o bioprocesso econômico e com grande potencial na aplicação biotecnológica.
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Produkce toxinů bakterií Bacillus subtilis a jejich role v konkurenčním boji s dalšími bakteriemi / Production of toxins by Bacillus subtilis and their roles in interspecies competitions.Šureková, Kristína January 2021 (has links)
Bacillus subtilis is a gram positive soil bacterium that is surrounded by many other microorganisms its environment. That is why it is necessary for the bacterium to be able to fight with these microorganisms for the nutrients and living space. B. subtilis contains the modules in its genetic make-up that improve its ability to compete. These modules are called the toxin-antitoxin systems. This Diploma Thesis is trying to identify yet undescribed extracellular toxins produced by the wild type BSB1 strain of B. subtilis. The related microorganism Bacillus megaterium was used as a competing bacterium. The contact-dependent or independent manner of killing the competing bacterium was demonstrated using this model. By deletion analysis and comparisons of the genomes of the various strains of B. subtilis, the SPβ prophage was first identified as a region containing an unknown toxin(s). Analysis of the extracellular proteome of B. subtilis subsequently revealed an unknown toxin (or toxin complex, respectively) of the molecular weight exceeding 100 kDa. Even more fascinating was the finding that such a large protein molecule is resistant to the pancreatic protease, trypsin. Subsequent non-enzymatic cyanogen bromide cleavage of the extracellular proteins and their analysis by mass spectrometry revealed...
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Regulation of aminoacyl-tRNA synthetase genes in <I>Bacillus subtilis</I>Williams-Wagner, Rebecca N. 30 September 2016 (has links)
No description available.
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Chladová adaptace ve stacionární fázi u Bacillus subtilis / Cold adaptation in stationary phase in Bacillus subtilisBeranová, Anna January 2010 (has links)
Cold adaptation in stationary phase in Bacillus subtilis One of the most important abiotic factor which influences life of bacterial cells is the ambient temperature. A decrease of this temperature is usually accompanied usually with the loss of the fluidity of bacterial cytoplasmatic membrane. While the mechanisms of the responses to the cold shock during the exponential phase of growth are well known for Bacillus subtilis, the responses of stationary phase cells had not been studied yet (despite the stationary phase is the most common state of microorganism in the nature). There are two independent mechanisms which restores much needed fluidity in Bacillus subtilis - short-term adaptation and long-term adaptation. Short-term adaptation is based on the function of fatty acid desaturase coded by des gene. Long-term adaptation relies on the change in ratio of iso- and anteiso- branched fatty acids. In this work we examinated membrane adaptation during stationary phase under two different conditions, namely under cultivation at stable low temperature and after cold shock. The highest activity of Pdes was observed for cultivation at 25 řC and for the cold shock applied from cultivation in 37 řC to 25 řC. Anisotropy measurements and fatty acids analysis were also performed. Results indicated, that the...
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Studium vlivu genu yxkO Bacillus subtilis na motilitu během odpovědi na osmotický stres. / Study of effect of Bacillus subtilis yxkO gene on motility during stress response to osmotic upshift.Streitová, Eliška January 2010 (has links)
Bacillus subtilis is gram-positive soil bacteria. In its natural environment it is constantly exposed to changes of chemical and physical conditons, including changes of osmolality. It responds to high osmolality by transporting of potassium ions and afterthat transporting and/or synthetising of compatible solutes. In last years the mutant strain Bacillus subtilis L-42 was isolated with non-specific insertional mutagenesis (mini Tn10) in our laboratory. This strain displays limited growth and inability to cope with hyperosmotic shock in a defined medium with potassium concentration of < 1 mmol/l. Insertion of transposon was located in yxkO gene which encodes a protein of unknown biological function. Some other data also indicate a possible role of disruption of yxkO gene in regulation of expression of hag gene, which encodes flagelin - a pivotal protein of bacterial flagellum. The goal of this thesis was to clarify if the disruption of yxkO gene influences motility and whether is affected the transcription of hag gene. With integrative vector pMUTIN4 a mutant strain with specific mutation of yxkO gene was prepared. Vector was pasted into chromosome of Bacillus subtilis strain 1A839 - genotype of this strain allows to extrude the known transcriptional regulation of hag gene. Cell's motility was...
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