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Pesquisa : G05.308.300 [Categoria DeCS]
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[PMID]:28461122
[Au] Autor:Werisch M; Berger U; Berendonk TU
[Ad] Endereço:Technische Universität Dresden, Department of Forest Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt 01735, Germany. Electronic address: martin.werisch@tu-dresden.de.
[Ti] Título:Conjugative plasmids enable the maintenance of low cost non-transmissible plasmids.
[So] Source:Plasmid;91:96-104, 2017 May.
[Is] ISSN:1095-9890
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Some plasmids can be transferred by conjugation to other bacterial hosts. But almost half of the plasmids are non-transmissible. These plasmid types can only be transmitted to the daughter cells of their host after bacterial fission. Previous studies suggest that non-transmissible plasmids become extinct in the absence of selection of their encoded traits, as plasmid-free bacteria are more competitive. Here, we aim to identify mechanisms that enable non-transmissible plasmids to persist, even if they are not beneficial. For this purpose, an individual-based model for plasmid population dynamics was set up and carefully tested for structural consistency and plausibility. Our results demonstrate that non-transmissible plasmids can be stably maintained in a population, even if they impose a substantial burden on their host cells growth. A prerequisite is the co-occurrence of an incompatible and costly conjugative plasmid type, which indirectly facilitates the preservation of the non-transmissible type. We suggest that this constellation might be considered as a potential mechanism maintaining plasmids and associated antibiotic resistances. It should be investigated in upcoming laboratory experiments.
[Mh] Termos MeSH primário: Bactérias/genética
Conjugação Genética
Regulação Bacteriana da Expressão Gênica
Transferência Genética Horizontal
Modelos Estatísticos
Plasmídeos/química
[Mh] Termos MeSH secundário: Bactérias/metabolismo
Simulação por Computador
Aptidão Genética
Plasmídeos/metabolismo
Seleção Genética
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  2 / 40730 MEDLINE  
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[PMID]:28461121
[Au] Autor:Hall JPJ; Brockhurst MA; Dytham C; Harrison E
[Ad] Endereço:Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
[Ti] Título:The evolution of plasmid stability: Are infectious transmission and compensatory evolution competing evolutionary trajectories?
[So] Source:Plasmid;91:90-95, 2017 May.
[Is] ISSN:1095-9890
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Conjugative plasmids are widespread and play an important role in bacterial evolution by accelerating adaptation through horizontal gene transfer. However, explaining the long-term stability of plasmids remains challenging because segregational loss and the costs of plasmid carriage should drive the loss of plasmids though purifying selection. Theoretical and experimental studies suggest two key evolutionary routes to plasmid stability: First, the evolution of high conjugation rates would allow plasmids to survive through horizontal transmission as infectious agents, and second, compensatory evolution to ameliorate the cost of plasmid carriage can weaken purifying selection against plasmids. How these two evolutionary strategies for plasmid stability interact is unclear. Here, we summarise the literature on the evolution of plasmid stability and then use individual based modelling to investigate the evolutionary interplay between the evolution of plasmid conjugation rate and cost amelioration. We find that, individually, both strategies promote plasmid stability, and that they act together to increase the likelihood of plasmid survival. However, due to the inherent costs of increasing conjugation rate, particularly where conjugation is unlikely to be successful, our model predicts that amelioration is the more likely long-term solution to evolving stable bacteria-plasmid associations. Our model therefore suggests that bacteria-plasmid relationships should evolve towards lower plasmid costs that may forestall the evolution of highly conjugative, 'infectious' plasmids.
[Mh] Termos MeSH primário: Bactérias/genética
Conjugação Genética
Regulação Bacteriana da Expressão Gênica
Transferência Genética Horizontal
Modelos Estatísticos
Plasmídeos/química
[Mh] Termos MeSH secundário: Bactérias/metabolismo
Evolução Biológica
Cromossomos Bacterianos/química
Cromossomos Bacterianos/metabolismo
Aptidão Genética
Loci Gênicos
Mutagênese Insercional
Plasmídeos/metabolismo
Seleção Genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  3 / 40730 MEDLINE  
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[PMID]:28461452
[Au] Autor:Bosserman RE; Champion PA
[Ad] Endereço:Department of Biological Sciences, Eck Institute for Global Health, Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana, USA.
[Ti] Título:Esx Systems and the Mycobacterial Cell Envelope: What's the Connection?
[So] Source:J Bacteriol;199(17), 2017 09 01.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Mycobacterial 6-kDa early secreted antigenic target (ESAT-6) system (ESX) exporters transport proteins across the cytoplasmic membrane. Many proteins transported by ESX systems are then translocated across the mycobacterial cell envelope and secreted from the cell. Although the mechanism underlying protein transport across the mycolate outer membrane remains elusive, the ESX systems are closely connected with and localize to the cell envelope. Links between ESX-associated proteins, cell wall synthesis, and the maintenance of cell envelope integrity have been reported. Genes encoding the ESX systems and those required for biosynthesis of the mycobacterial envelope are coregulated. Here, we review the interplay between ESX systems and the mycobacterial cell envelope.
[Mh] Termos MeSH primário: Parede Celular/metabolismo
Mycobacterium/metabolismo
Sistemas de Secreção Tipo VII/metabolismo
[Mh] Termos MeSH secundário: Regulação Bacteriana da Expressão Gênica
Modelos Biológicos
Mycobacterium/genética
Transporte Proteico
Sistemas de Secreção Tipo VII/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Type VII Secretion Systems)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  4 / 40730 MEDLINE  
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[PMID]:28461449
[Au] Autor:Stubbendieck RM; Straight PD
[Ad] Endereço:Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, USA.
[Ti] Título:Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology.
[So] Source:J Bacteriol;199(18), 2017 09 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, and sp. strain Mg1. Using this model, we previously found that linearmycins produced by sp. strain Mg1 cause lysis of cells and degradation of colony matrix. We identified strains of with mutations in the two-component signaling system operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter operon, particularly and , is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.
[Mh] Termos MeSH primário: Antibacterianos/metabolismo
Antibiose
Bacillus subtilis/fisiologia
Biofilmes/crescimento & desenvolvimento
Viabilidade Microbiana
Streptomyces/fisiologia
[Mh] Termos MeSH secundário: Transportadores de Cassetes de Ligação de ATP/metabolismo
Fusão Gênica Artificial
Bacillus subtilis/efeitos dos fármacos
Elementos de DNA Transponíveis
Perfilação da Expressão Gênica
Regulação Bacteriana da Expressão Gênica
Mutagênese Insercional
Mutação
Transdução de Sinais
Streptomyces/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (ATP-Binding Cassette Transporters); 0 (Anti-Bacterial Agents); 0 (DNA Transposable Elements)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


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[PMID]:28461450
[Au] Autor:Rothstein DM; Lazinski D; Osburne MS; Sonenshein AL
[Ad] Endereço:Graduate Program in Molecular Biology, Tufts University School of Medicine, Boston, Massachusetts, USA.
[Ti] Título:A Mutation in the Bacillus subtilis rsbU Gene That Limits RNA Synthesis during Sporulation.
[So] Source:J Bacteriol;199(14), 2017 07 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Mutants of that are temperature sensitive for RNA synthesis during sporulation were isolated after selection with a P suicide agent. Whole-genome sequencing revealed that two of the mutants carried an identical lesion in the gene, which encodes a phosphatase that indirectly activates SigB, the stress-responsive RNA polymerase sigma factor. The mutation appeared to cause RsbU to be hyperactive, because the mutants were more resistant than the parent strain to ethanol stress. In support of this hypothesis, pseudorevertants that regained wild-type levels of sporulation at high temperature had secondary mutations that prevented expression of the mutant gene. The properties of these RsbU mutants support the idea that activation of SigB diminishes the bacterium's ability to sporulate. Most bacterial species encode multiple RNA polymerase promoter recognition subunits (sigma factors). Each sigma factor directs RNA polymerase to different sets of genes; each gene set typically encodes proteins important for responses to specific environmental conditions, such as changes in temperature, salt concentration, and nutrient availability. A selection for mutants of that are temperature sensitive for RNA synthesis during sporulation unexpectedly yielded strains with a point mutation in , a gene that encodes a protein that normally activates sigma factor B (SigB) under conditions of salt stress. The mutation appears to cause RsbU, and therefore SigB, to be active inappropriately, thereby inhibiting, directly or indirectly, the ability of the cells to transcribe sporulation genes.
[Mh] Termos MeSH primário: Bacillus subtilis/metabolismo
Proteínas de Bactérias/metabolismo
Regulação Bacteriana da Expressão Gênica/fisiologia
Monoéster Fosfórico Hidrolases/metabolismo
RNA Bacteriano/biossíntese
Esporos Bacterianos/fisiologia
[Mh] Termos MeSH secundário: Bacillus subtilis/genética
Proteínas de Bactérias/genética
Etanol/farmacologia
Genoma Bacteriano
Temperatura Alta
Mutação
Fosfatos/metabolismo
Monoéster Fosfórico Hidrolases/genética
Radioisótopos de Fósforo
Estresse Fisiológico/efeitos dos fármacos
Estresse Fisiológico/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Phosphates); 0 (Phosphorus Radioisotopes); 0 (RNA, Bacterial); 3K9958V90M (Ethanol); EC 3.1.3.2 (Phosphoric Monoester Hydrolases); EC 3.1.3.3 (RsbU protein, Bacillus subtilis)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  6 / 40730 MEDLINE  
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[PMID]:28461448
[Au] Autor:Borchert AJ; Downs DM
[Ad] Endereço:Department of Microbiology, University of Georgia, Athens, Georgia, USA.
[Ti] Título:The Response to 2-Aminoacrylate Differs in Escherichia coli and Salmonella enterica, despite Shared Metabolic Components.
[So] Source:J Bacteriol;199(14), 2017 07 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The metabolic network of an organism includes the sum total of the biochemical reactions present. In microbes, this network has an impeccable ability to sense and respond to perturbations caused by internal or external stimuli. The metabolic potential (i.e., network structure) of an organism is often drawn from the genome sequence, based on the presence of enzymes deemed to indicate specific pathways. and are members of the family of Gram-negative bacteria that share the majority of their metabolic components and regulatory machinery as the "core genome." In , the ability of the enamine intermediate 2-aminoacrylate (2AA) to inactivate a number of pyridoxal 5'-phosphate (PLP)-dependent enzymes has been established In this study, 2AA metabolism and the consequences of its accumulation were investigated in The data showed that despite the conservation of all relevant enzymes, and differed in both the generation and detrimental consequences of 2AA. In total, these findings suggest that the structure of the metabolic network surrounding the generation and response to endogenous 2AA stress differs between and This work compared the metabolic networks surrounding the endogenous stressor 2-aminoacrylate in two closely related members of the The data showed that despite the conservation of all relevant enzymes in this metabolic node, the two closely related organisms diverged in their metabolic network structures. This work highlights how a set of conserved components can generate distinct network architectures and how this can impact the physiology of an organism. This work defines a model to expand our understanding of the 2-aminoacrylate stress response and the differences in metabolic structures and cellular milieus between and .
[Mh] Termos MeSH primário: Acrilatos/farmacologia
Proteínas de Bactérias/metabolismo
Escherichia coli/efeitos dos fármacos
Salmonella enterica/efeitos dos fármacos
[Mh] Termos MeSH secundário: Adenina/farmacologia
Ácido Aspártico/farmacologia
Proteínas de Bactérias/genética
Escherichia coli/metabolismo
Deleção de Genes
Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos
Regulação Enzimológica da Expressão Gênica/fisiologia
L-Serina Desidratase/genética
L-Serina Desidratase/metabolismo
Salmonella enterica/metabolismo
Estresse Fisiológico/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Acrylates); 0 (Bacterial Proteins); 30KYC7MIAI (Aspartic Acid); EC 4.3.1.17 (L-Serine Dehydratase); JAC85A2161 (Adenine)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  7 / 40730 MEDLINE  
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[PMID]:28461447
[Au] Autor:Hoffmann MC; Pfänder Y; Tintel M; Masepohl B
[Ad] Endereço:Biologie der Mikroorganismen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, Bochum, Germany.
[Ti] Título:Bacterial PerO Permeases Transport Sulfate and Related Oxyanions.
[So] Source:J Bacteriol;199(14), 2017 07 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:synthesizes the high-affinity ABC transporters CysTWA and ModABC to specifically import the chemically related oxyanions sulfate and molybdate, respectively. In addition, has the low-affinity permease PerO acting as a general oxyanion transporter, whose elimination increases tolerance to molybdate and tungstate. Although PerO-like permeases are widespread in bacteria, their function has not been examined in any other species to date. Here, we present evidence that PerO permeases from the alphaproteobacteria , , , and and the gammaproteobacterium functionally substitute for PerO in sulfate uptake and sulfate-dependent growth, as shown by assimilation of radioactively labeled sulfate and heterologous complementation. Disruption of genes in , , and increased tolerance to tungstate and, in the case of , to molybdate, suggesting that heterometal oxyanions are common substrates of PerO permeases. This study supports the view that bacterial PerO permeases typically transport sulfate and related oxyanions and, hence, form a functionally conserved permease family. Despite the widespread distribution of PerO-like permeases in bacteria, our knowledge about PerO function until now was limited to one species, In this study, we showed that PerO proteins from diverse bacteria are functionally similar to the prototype, suggesting that PerO permeases form a conserved family whose members transport sulfate and related oxyanions.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Proteínas de Membrana Transportadoras/metabolismo
Rhodobacter capsulatus/enzimologia
Sulfatos/metabolismo
[Mh] Termos MeSH secundário: Ânions/metabolismo
Proteínas de Bactérias/genética
Transporte Biológico/fisiologia
Regulação Bacteriana da Expressão Gênica/fisiologia
Regulação Enzimológica da Expressão Gênica/fisiologia
Proteínas de Membrana Transportadoras/genética
Mutação
Rhodobacter capsulatus/genética
Rhodobacter capsulatus/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Anions); 0 (Bacterial Proteins); 0 (Membrane Transport Proteins); 0 (Sulfates)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  8 / 40730 MEDLINE  
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[PMID]:28461445
[Au] Autor:Yamamoto S; Ohnishi M
[Ad] Endereço:Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan yshouji@nih.go.jp.
[Ti] Título:Glucose-Specific Enzyme IIA of the Phosphoenolpyruvate:Carbohydrate Phosphotransferase System Modulates Chitin Signaling Pathways in Vibrio cholerae.
[So] Source:J Bacteriol;199(18), 2017 09 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In , the genes required for chitin utilization and natural competence are governed by the chitin-responsive two-component system (TCS) sensor kinase ChiS. In the classical TCS paradigm, a sensor kinase specifically phosphorylates a cognate response regulator to activate gene expression. However, our previous genetic study suggested that ChiS stimulates the non-TCS transcriptional regulator TfoS by using mechanisms distinct from classical phosphorylation reactions (S. Yamamoto, J. Mitobe, T. Ishikawa, S. N. Wai, M. Ohnishi, H. Watanabe, and H. Izumiya, Mol Microbiol 91:326-347, 2014, https://doi.org/10.1111/mmi.12462). TfoS specifically activates the transcription of , encoding a small regulatory RNA essential for competence gene expression. Whether ChiS and TfoS interact directly remains unknown. To determine if other factors mediate the communication between ChiS and TfoS, we isolated transposon mutants that turned off :: expression but possessed intact and genes. We demonstrated an unexpected association of chitin-induced signaling pathways with the glucose-specific enzyme IIA (EIIA ) of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) for carbohydrate uptake and catabolite control of gene expression. Genetic and physiological analyses revealed that dephosphorylated EIIA inactivated natural competence and transcription. Chitin-induced expression of the operon, which is required for chitin transport and catabolism, was also repressed by dephosphorylated EIIA Furthermore, the regulation of and expression by EIIA was dependent on ChiS and intracellular levels of ChiS were not affected by disruption of the gene encoding EIIA These results define a previously unknown connection between the PTS and chitin signaling pathways in and suggest a strategy whereby this bacterium can physiologically adapt to the existing nutrient status. The EIIA protein of the PTS coordinates a wide variety of physiological functions with carbon availability. In this report, we describe an unexpected association of chitin-activated signaling pathways in with EIIA The signaling pathways are governed by the chitin-responsive TCS sensor kinase ChiS and lead to the induction of chitin utilization and natural competence. We show that dephosphorylated EIIA inhibits both signaling pathways in a ChiS-dependent manner. This inhibition is different from classical catabolite repression that is caused by lowered levels of cyclic AMP. This work represents a newly identified connection between the PTS and chitin signaling pathways in and suggests a strategy whereby this bacterium can physiologically adapt to the existing nutrient status.
[Mh] Termos MeSH primário: Quitina/metabolismo
Regulação Bacteriana da Expressão Gênica
Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo
Transdução de Sinais
Vibrio cholerae/genética
Vibrio cholerae/metabolismo
[Mh] Termos MeSH secundário: Elementos de DNA Transponíveis
Redes Reguladoras de Genes
Mutagênese Insercional
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (DNA Transposable Elements); 1398-61-4 (Chitin); EC 2.7.1.- (Phosphoenolpyruvate Sugar Phosphotransferase System)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  9 / 40730 MEDLINE  
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[PMID]:28461446
[Au] Autor:Pequegnat B; Laird RM; Ewing CP; Hill CL; Omari E; Poly F; Monteiro MA; Guerry P
[Ad] Endereço:Department of Chemistry, University of Guelph, Guelph, Ontario, Canada.
[Ti] Título:Phase-Variable Changes in the Position of -Methyl Phosphoramidate Modifications on the Polysaccharide Capsule of Campylobacter jejuni Modulate Serum Resistance.
[So] Source:J Bacteriol;199(14), 2017 07 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:polysaccharide capsules (CPS) are characterized by the presence of nonstoichiometric -methyl phosphoramidate (MeOPN) modifications. The lack of stoichiometry is due to phase variation at homopolymeric tracts within the MeOPN transferase genes. strain 81-176 contains two MeOPN transferase genes and has been shown previously to contain MeOPN modifications at the 2 and 6 positions of the galactose (Gal) moiety in the CPS. We demonstrate here that one of the two MeOPN transferases, encoded by CJJ81176_1435, is bifunctional and is responsible for the addition of MeOPN to both the 2 and the 6 positions of Gal. A new MeOPN at the 4 position of Gal was observed in a mutant lacking the CJJ81176_1435 transferase and this was encoded by the CJJ81176_1420 transferase. During routine growth of 81-176, the CJJ81176_1420 transferase was predominantly in an off configuration, while the CJJ81176_1435 transferase was primarily on. However, exposure to normal human serum selected for cells expressing the CJJ81176_1420 transferase. MeOPN modifications appear to block binding of naturally occurring antibodies to the 81-176 CPS. The absence of MeOPN-4-Gal resulted in enhanced sensitivity to serum killing, whereas the loss of MeOPN-2-Gal and MeOPN-6-Gal resulted in enhanced resistance to serum killing, perhaps by allowing more MeOPN to be put onto the 4 position of Gal. undergoes phase variation in genes encoding surface antigens, leading to the concept that a strain of this organism consists of multiple genotypes that are selected for fitness in various environments. Methyl phosphoramidate modifications on the capsule of block access of preexisting antibodies in normal human sera to the polysaccharide chain, thus preventing activation of the classical arm of the complement cascade. We show that the capsule of strain 81-176 contains more sites of MeOPN modifications than previously recognized and that one site, on the 4 position of galactose, is more critical to complement resistance than the others. Exposure to normal human serum selects for variants in the population expressing this MeOPN modification.
[Mh] Termos MeSH primário: Amidas
Cápsulas Bacterianas/fisiologia
Campylobacter jejuni/metabolismo
Soros Imunes/imunologia
Ácidos Fosfóricos
Polissacarídeos Bacterianos/metabolismo
[Mh] Termos MeSH secundário: Animais
Anticorpos Antibacterianos
Clonagem Molecular
Regulação Bacteriana da Expressão Gênica/fisiologia
Epitopos Imunodominantes
Mutação
Polissacarídeos Bacterianos/química
Polissacarídeos Bacterianos/imunologia
Coelhos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amides); 0 (Antibodies, Bacterial); 0 (Immune Sera); 0 (Immunodominant Epitopes); 0 (Phosphoric Acids); 0 (Polysaccharides, Bacterial); 9Q189608GB (phosphoramidic acid)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  10 / 40730 MEDLINE  
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[PMID]:29335514
[Au] Autor:Kaiser M; Jug F; Julou T; Deshpande S; Pfohl T; Silander OK; Myers G; van Nimwegen E
[Ad] Endereço:Biozentrum, University of Basel and Swiss Institute of Bioinformatics, Klingelbergstrasse 50/70, 4056, Basel, Switzerland.
[Ti] Título:Monitoring single-cell gene regulation under dynamically controllable conditions with integrated microfluidics and software.
[So] Source:Nat Commun;9(1):212, 2018 01 15.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Much is still not understood about how gene regulatory interactions control cell fate decisions in single cells, in part due to the difficulty of directly observing gene regulatory processes in vivo. We introduce here a novel integrated setup consisting of a microfluidic chip and accompanying analysis software that enable long-term quantitative tracking of growth and gene expression in single cells. The dual-input Mother Machine (DIMM) chip enables controlled and continuous variation of external conditions, allowing direct observation of gene regulatory responses to changing conditions in single cells. The Mother Machine Analyzer (MoMA) software achieves unprecedented accuracy in segmenting and tracking cells, and streamlines high-throughput curation with a novel leveraged editing procedure. We demonstrate the power of the method by uncovering several novel features of an iconic gene regulatory program: the induction of Escherichia coli's lac operon in response to a switch from glucose to lactose.
[Mh] Termos MeSH primário: Regulação Bacteriana da Expressão Gênica
Técnicas Analíticas Microfluídicas/métodos
Análise de Célula Única/métodos
Software
[Mh] Termos MeSH secundário: Algoritmos
Rastreamento de Células/instrumentação
Rastreamento de Células/métodos
Escherichia coli/citologia
Escherichia coli/efeitos dos fármacos
Escherichia coli/genética
Glucose/farmacologia
Óperon Lac/genética
Lactose/farmacologia
Análise de Célula Única/instrumentação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
IY9XDZ35W2 (Glucose); J2B2A4N98G (Lactose)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180305
[Lr] Data última revisão:
180305
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180117
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02505-0



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