Gotowa bibliografia na temat „Pseudomonas aeruginosa PA14”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Zobacz listy aktualnych artykułów, książek, rozpraw, streszczeń i innych źródeł naukowych na temat „Pseudomonas aeruginosa PA14”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Artykuły w czasopismach na temat "Pseudomonas aeruginosa PA14"
1
Choi, Ji Young, Costi D. Sifri, Boyan C. Goumnerov, Laurence G. Rahme, Frederick M. Ausubel i Stephen B. Calderwood. "Identification of Virulence Genes in a Pathogenic Strain of Pseudomonas aeruginosa by Representational Difference Analysis". Journal of Bacteriology 184, nr 4 (15.02.2002): 952–61. http://dx.doi.org/10.1128/jb.184.4.952-961.2002.
Pełny tekst źródłaStreszczenie:
ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that may cause severe infections in humans and other vertebrates. In addition, a human clinical isolate of P. aeruginosa, strain PA14, also causes disease in a variety of nonvertebrate hosts, including plants, Caenorhabditis elegans, and the greater wax moth, Galleria mellonella. This has led to the development of a multihost pathogenesis system in which plants, nematodes, and insects have been used as adjuncts to animal models for the identification of P. aeruginosa virulence factors. Another approach to identifying virulence genes in bacteria is to take advantage of the natural differences in pathogenicity between isolates of the same species and to use a subtractive hybridization technique to recover relevant genomic differences. The sequenced strain of P. aeruginosa, strain PAO1, has substantial differences in virulence from strain PA14 in several of the multihost models of pathogenicity, and we have utilized the technique of representational difference analysis (RDA) to directly identify genomic differences between P. aeruginosa strains PA14 and PAO1. We have found that the pilC, pilA, and uvrD genes in strain PA14 differ substantially from their counterparts in strain PAO1. In addition, we have recovered a gene homologous to the ybtQ gene from Yersinia, which is specifically present in strain PA14 but absent in strain PAO1. Mutation of the ybtQ homolog in P. aeruginosa strain PA14 significantly attenuates the virulence of this strain in both G. mellonella and a burned mouse model of sepsis to levels comparable to those seen with PAO1. This suggests that the increased virulence of P. aeruginosa strain PA14 compared to PAO1 may relate to specific genomic differences identifiable by RDA.
2
Srichaisupakit, Akkaraphol, Peechanika Chopjitt i Anusak Kerdsin. "Characterization of N4-like Pseudomonas Phage vB_Pae-PA14 Isolated from Seawater Sampled in Thailand". Journal of Pure and Applied Microbiology 15, nr 4 (22.11.2021): 2347–57. http://dx.doi.org/10.22207/jpam.15.4.59.
Pełny tekst źródłaStreszczenie:
Bacteriophage, a predator virus of bacteria, is an abundant biological entity in the biosphere. With ultimate applications in medicine and biotechnology, new phages are extensively being isolated and characterized. The objective of the present study was to characterize lytic bacteriophage vB_Pae-PA14 infecting Pseudomonas aeruginosa ATCC 27853 that was isolated from seawater in Thailand. vB_Pae-PA14 was subjected to whole genome phylogenetic analysis, host range test, biofilm test and characterization. Results showed that the phage belonged to a group of N4-like viruses, could infect P. aeruginosa isolates including carbapenem-resistant P. aeruginosa. The burst size of vB_Pae-PA14 was 86 plaque-forming unit/infected cells. Also, the phage showed a greater ability to control planktonic P. aeruginosa cells than the biofilm cells. Phage could withstand physical stresses especially the high salt concentration. In brief, lytic bacteriophage vB_Pae-PA14 infecting P. aeruginosa was isolated and characterized, which might be useful in further bacteriophage lytic applications.
3
Jander, Georg, Laurence G. Rahme i Frederick M. Ausubel. "Positive Correlation between Virulence ofPseudomonas aeruginosa Mutants in Mice and Insects". Journal of Bacteriology 182, nr 13 (1.07.2000): 3843–45. http://dx.doi.org/10.1128/jb.182.13.3843-3845.2000.
Pełny tekst źródłaStreszczenie:
ABSTRACT Strain PA14, a human clinical isolate of Pseudomonas aeruginosa, is pathogenic in mice and insects (Galleria mellonella). Analysis of 32 different PA14 mutants in these two hosts showed a novel positive correlation in the virulence patterns. Thus, G. mellonella is a good model system for identifying mammalian virulence factors of P. aeruginosa.
4
Kukavica-Ibrulj, Irena, Alessandra Bragonzi, Moira Paroni, Craig Winstanley, François Sanschagrin, George A. O'Toole i Roger C. Levesque. "In Vivo Growth of Pseudomonas aeruginosa Strains PAO1 and PA14 and the Hypervirulent Strain LESB58 in a Rat Model of Chronic Lung Infection". Journal of Bacteriology 190, nr 8 (14.12.2007): 2804–13. http://dx.doi.org/10.1128/jb.01572-07.
Pełny tekst źródłaStreszczenie:
ABSTRACT Pseudomonas aeruginosa chronic lung infections are the major cause of morbidity and mortality in cystic fibrosis (CF) patients. The P. aeruginosa strains PAO1 and PA14 were compared with the Liverpool epidemic strain LESB58 to assess in vivo growth, infection kinetics, and bacterial persistence and localization within tissues in a rat model of chronic lung infection. The three P. aeruginosa strains demonstrated similar growth curves in vivo but differences in tissue distribution. The LESB58 strain persisted in the bronchial lumen, while the PAO1 and PA14 strains were found localized in the alveolar regions and grew as macrocolonies after day 7 postinfection. Bacterial strains were compared for swimming and twitching motility and for the production of biofilm. The P. aeruginosa LESB58 strain produced more biofilm than PAO1 and PA14. Competitive index (CI) analysis of PAO1, PA14, and LESB58 in vivo indicated CI values of 0.002, 0.0002, and 0.14 between PAO1-PA14, PAO1-LESB58, and LESB58-PA14, respectively. CI analysis comparing the in vivo growth of the PAO1 ΔPA5441 mutant and four PA14 surface attachment-defective (sad) mutants gave CI values 10 to 1,000 times lower in competitions with their respective wild-type strains PAO1 and PA14. P. aeruginosa strains studied in the rat model of chronic lung infection demonstrated similar in vivo growth but differences in virulence as shown with a competitive in vivo assay. These differences were further confirmed with biofilm and motility in vitro assays, where strain LESB58 produced more biofilm but had less capacity for motility than PAO1 and PA14.
5
Al-Haidari, Rwaida A., Mona I. Shaaban, Sabrin R. M. Ibrahim i Gamal A. Mohamed. "ANTI-QUORUM SENSING ACTIVITY OF SOME MEDICINAL PLANTS". African Journal of Traditional, Complementary and Alternative Medicines 13, nr 5 (12.08.2016): 67–71. http://dx.doi.org/10.21010/ajtcam.v13i5.10.
Pełny tekst źródłaStreszczenie:
Background: Quorum sensing is the key regulator of virulence factors of Pseudomonas aeruginosa such as biofilm formation, motility, productions of proteases, hemolysin, pyocyanin, and toxins.
Material and Methods: Quorum sensing inhibitory (OSI) effect of the alcohol extracts of 20 medicinal plants was evaluated by Chromobacterium violaceum reporter using agar cup diffusion method. The efficient QSI extracts were tested for their activity against biofilm synthesis, motility, and synthesis of pyocyanin from P. aeruginosa PA14
Results: The extracts of Citrus sinensis, Laurus nobilis, Elettaria cardamomum, Allium cepa, and Coriandrum sativum exhibited potent quorum quenching effect. On the other hand, Psidium guajava and Mentha longifolia extracts showed lower QSI activity. These extracts exhibited significant elimination of pyocyanin formation and biofilm development of Pseudomonas aeruginosa PA14. In addition, they significantly inhibited twitching and swimming motilities of P. aeruginosa PA14.
Conclusion: This study illustrated for the first time the importance of C. sinensis, L. nobilis, E. cardamomum, A. cepa, and C. sativum as quorum sensing inhibitors and virulence suppressors of P. aeruginosa.
6
Fu, Tse-Kai, Sim-Kun Ng, Yi-En Chen, Yuan-Chuan Lee, Fruzsina Demeter, Mihály Herczeg, Anikó Borbás i in. "Rhamnose Binding Protein as an Anti-Bacterial Agent—Targeting Biofilm of Pseudomonas aeruginosa". Marine Drugs 17, nr 6 (14.06.2019): 355. http://dx.doi.org/10.3390/md17060355.
Pełny tekst źródłaStreszczenie:
More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.
7
Wang, Yun, Suzanne E. Kern i Dianne K. Newman. "Endogenous Phenazine Antibiotics Promote Anaerobic Survival of Pseudomonas aeruginosa via Extracellular Electron Transfer". Journal of Bacteriology 192, nr 1 (30.10.2009): 365–69. http://dx.doi.org/10.1128/jb.01188-09.
Pełny tekst źródłaStreszczenie:
ABSTRACT Antibiotics are increasingly recognized as having other, important physiological functions for the cells that produce them. An example of this is the effect that phenazines have on signaling and community development for Pseudomonas aeruginosa (L. E. Dietrich, T. K. Teal, A. Price-Whelan, and D. K. Newman, Science 321:1203-1206, 2008). Here we show that phenazine-facilitated electron transfer to poised-potential electrodes promotes anaerobic survival but not growth of Pseudomonas aeruginosa PA14 under conditions of oxidant limitation. Other electron shuttles that are reduced but not made by PA14 do not facilitate survival, suggesting that the survival effect is specific to endogenous phenazines.
8
Sass, Gabriele, Pallabi Shrestha i David A. Stevens. "Pseudomonas aeruginosa Virulence Factors Support Voriconazole Effects on Aspergillus fumigatus". Pathogens 10, nr 5 (26.04.2021): 519. http://dx.doi.org/10.3390/pathogens10050519.
Pełny tekst źródłaStreszczenie:
Pseudomonas aeruginosa and Aspergillus fumigatus are pathogens that are associated with deterioration of lung function, e.g., in persons with cystic fibrosis (CF). There is evidence that co-infections with these pathogens cause airway inflammation and aggravate pathology in CF lungs. Intermicrobial competition of P. aeruginosa and A. fumigatus has been described, but it is unknown how anti-fungal therapy is affected. The anti-fungal azole voriconazole (VCZ), supernatants of P. aeruginosa laboratory isolates PA14 or PAO1, or clinical isolate Pa10 independently inhibited biofilm metabolism of A. fumigatus isolates 10AF and AF13073. When VCZ and supernatants were combined at their IC50s, synergistic effects on A. fumigatus were found. Synergistic effects were no longer observed when P. aeruginosa supernatants were prepared in the presence of iron, or when P. aeruginosa mutants were lacking the ability to produce pyoverdine and pyochelin. Combination of pure P. aeruginosa products pyoverdine, pyochelin, and pyocyanin with VCZ showed synergistic anti-fungal effects. Combining VCZ with P. aeruginosa supernatants also improved its MIC and MFC against planktonic A. fumigatus. In summary, in the case of P. aeruginosa–A. fumigatus co-infections, it appeared that the P. aeruginosa co-infection facilitated therapy of the Aspergillus; lower concentrations of VCZ might be sufficient to control fungal growth.
9
Budzik, Jonathan M., William A. Rosche, Arne Rietsch i George A. O'Toole. "Isolation and Characterization of a Generalized Transducing Phage for Pseudomonas aeruginosa Strains PAO1 and PA14". Journal of Bacteriology 186, nr 10 (15.05.2004): 3270–73. http://dx.doi.org/10.1128/jb.186.10.3270-3273.2004.
Pełny tekst źródłaStreszczenie:
ABSTRACT A temperate, type IV pilus-dependent, double-stranded DNA bacteriophage named DMS3 was isolated from a clinical strain of Pseudomonas aeruginosa. A clear-plaque variant of this bacteriophage was isolated. DMS3 is capable of mediating generalized transduction within and between P. aeruginosa strains PA14 and PAO1, thus providing a useful tool for the genetic analysis of P. aeruginosa.
10
Van Alst, Nadine E., Melanie Wellington, Virginia L. Clark, Constantine G. Haidaris i Barbara H. Iglewski. "Nitrite Reductase NirS Is Required for Type III Secretion System Expression and Virulence in the Human Monocyte Cell Line THP-1 by Pseudomonas aeruginosa". Infection and Immunity 77, nr 10 (3.08.2009): 4446–54. http://dx.doi.org/10.1128/iai.00822-09.
Pełny tekst źródłaStreszczenie:
ABSTRACT The nitrate dissimilation pathway is important for anaerobic growth in Pseudomonas aeruginosa. In addition, this pathway contributes to P. aeruginosa virulence by using the nematode Caenorhabditis elegans as a model host, as well as biofilm formation and motility. We used a set of nitrate dissimilation pathway mutants to evaluate the virulence of P. aeruginosa PA14 in a model of P. aeruginosa-phagocyte interaction by using the human monocytic cell line THP-1. Both membrane nitrate reductase and nitrite reductase enzyme complexes were important for cytotoxicity during the interaction of P. aeruginosa PA14 with THP-1 cells. Furthermore, deletion mutations in genes encoding membrane nitrate reductase (ΔnarGH) and nitrite reductase (ΔnirS) produced defects in the expression of type III secretion system (T3SS) components, extracellular protease, and elastase. Interestingly, exotoxin A expression was unaffected in these mutants. Addition of exogenous nitric oxide (NO)-generating compounds to ΔnirS mutant cultures restored the production of T3SS phospholipase ExoU, whereas nitrite addition had no effect. These data suggest that NO generated via nitrite reductase NirS contributes to the regulation of expression of selected virulence factors in P. aeruginosa PA14.
Rozprawy doktorskie na temat "Pseudomonas aeruginosa PA14"
1
Magalhães, Larissa de Oliveira. "Caracterização de fatores sigma ECF de Pseudomonas aeruginosa PA14". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-02122016-144359/.
Pełny tekst źródłaStreszczenie:
A proteobactéria Pseudomonas aeruginosa é um patógeno oportunista em humanos, sendo associado a queimaduras e infecções pulmonares crônicas em pacientes com fibrose cística. Essas infecções são difíceis de erradicar devido à resistência intrínseca de P. aeruginosa a antibióticos e à formação de biofilmes. Essa bactéria é altamente capaz de adaptar ao ambiente, tem um metabolismo versátil e pode direcionar a expressão de genes por vários fatores sigma alternativos. Estes são subunidades para transcrição de conjuntos específicos de genes em bactérias e interagem com o cerne da RNA polimerase, levando ao reconhecimento do promotor e início da transcrição. Os fatores sigma alternativos permitem que bactérias redirecionem a sua expressão genética. Um grupo de fatores sigma alternativos é o grupo dos fatores sigma de função extracitoplasmática (ECF) que são envolvidos principalmente em funções do envelope celular. Esse trabalho teve como objetivo caracterizar dois fatores sigma ECF de função desconhecida, PA14_21550 e PA14_46810. A linhagem mutante Δ21550 foi analisada quanto a sua sobrevivência a diferentes estresses, observando-se que é mais resistente ao choque de 45°C que a linhagem selvagem. Esse fator sigma não é essencial para crescimento da bactéria em meio LB e meio mínimo M63 acrescido de glicose ou succinato. Além disso, observou-se que a superexpressão desse fator sigma aumenta a expressão da proteína hipotética PA14_30100, usando-se uma abordagem proteômica. O mutante de transposon para o fator sigma PA14_46810 apresenta melhor crescimento que a bactéria selvagem em meio M63 acrescido de glicose. Essa linhagem mostrou mesmo fenótipo para biofilme e formação de exopolissacarídeo que a bactéria selvagem. Ademais, foi realizada análise de transcritoma por RNA-Seq com a superexpressão do fator sigma PA14_46810 na linhagem selvagem. Na linhagem de superexpressão Observou-se que ocorre indução de genes envolvidos com a desnitrificação, transporte de moléculas e metabolismo de uma maneira geral, em relação à linhagem controle. Por outro lado, o excesso de PA14_46810 reprime principalmente genes envolvidos com a tradução de proteínas e síntese de espermidina. Este trabalho, portanto, trouxe novas informações sobre as funções de diferentes fatores sigma ECF de P. aeruginosa, contribuindo assim para um maior entendimento da fisiologia desta bactéria e sua adaptação a diferentes condições.The proteobacterium Pseudomonas aeruginosa is an opportunistic pathogen in humans, and it is associated to chronic pulmonary infections in patients with cystic fibrosis and burn wounds. These infections are difficult to eradicate due to P. aeruginosa intrinsic resistance to antibiotics and formation of biofilms, which allow the bacteria to adhere to biotic and abiotic surfaces. This bacterium is highly adaptaptable to the environment has a versatile metabolism and can direct the expression of genes by several alternative sigma factors. The sigma factors bind to the RNA polymerase core, providing recognition to promoter and transcription initiation. Therefore, the alternative sigma factors can redirect bacterial genetic expression by recognizing specific promoters. One subfamily of alternative sigma factors is the extracytoplasmic function (ECF) sigma factors, involved mostly in cell envelope functions. The aim of this work was characterize two ECF sigma factors with unknown function in P. aeruginosa, PA14_21550 and PA14_46810. The strain Δ21550 was analyzed for its survival in different stress conditions and it is more resistant in heat shock conditions at 45°C than the wild type strain. It was also observed that PA14_21550 sigma factor is not essential for bacterial growth in LB and M63 minimal medium added with glucose or succinate as the carbon source. Furthermore, overexpression of this sigma factor increases the expression of hypothetical protein PA14_30100, as verified by a proteomic approach. A strain insertionally inactivated in the PA14_46810 gene has better growth than the wild type strain in M63 added with glucose and the same phenotype regarding to biofilm formation and exopolysaccharide production as the wild type strain. Moreover, transcriptome analysis was carried out by RNA-Seq with overexpression of the PA14_46810 sigma factor in the wild type strain. Induction of genes involved in denitrification, transport of molecules and energetic metabolism in relation to the control strain was observed. On the other hand, excess of PA14_46810 represses genes involved in protein translation and spermidine synthesis. This work, therefore, brought new information about the functions of two ECF sigma of P. aeruginosa, thus contributing to a greater understanding of the physiology of this bacterium and its adaptation to different conditions.
2
Fischer, Sebastian [Verfasser]. "Genomdiversität der dominierenden Pseudomonas aeruginosa Klone C und PA14 / Sebastian Fischer". Hannover : Technische Informationsbibliothek (TIB), 2015. http://d-nb.info/1170428185/34.
Pełny tekst źródła
3
Borges, Ana Laura Boechat. "Caracterização da superexpressão do fator sigma ECF σx em Pseudomonas aeruginosa PA14". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-06082013-083551/.
Pełny tekst źródłaStreszczenie:
Pseudomonas aeruginosa é uma proteobactéria do grupo gama muito versátil, capaz de colonizar ambientes variados e infectar hospedeiros filogeneticamente distintos, incluindo humanos imunocomprometidos. Os fatores sigma de função extracitoplasmática (ECF) são membros de sistemas de sinalização de superfície celular (CSS), abundantes em P. aeruginosa. Vinte genes codificando fatores sigma ECF estão presentes nos genomas sequenciados de P. aeruginosa, a maioria fazendo parte de sistemas TonB relacionados à captação de ferro. Neste trabalho, seis fatores sigma pobremente caracterizados foram superexpressos na linhagem PA14 a partir de um promotor induzível por arabinose para investigar seu papel na expressão dos sistemas de dois componentes PvrSR e RcsCB, que atuam na regulação da fímbria CupD, além de sua influência no crescimento de culturas de P. aeruginosa. Não foi observado efeito positivo de nenhum dos fatores sigma testados na expressão dos sistemas de dois componentes e a superexpressão de cinco deles tampouco levou a qualquer alteração no crescimento, porém a produção de piocianina foi alterada na superexpressão de PA14_55550 e a superexpressão de PA14_26600 e PA14_46810 levou a um discreto aumento no início da formação de biofilme em PA14. Por outro lado, culturas superexpressando σx (ALB04) apresentaram um perfil alterado de lipopolissacarídeo e uma curva de crescimento bifásica, alcançando precocemente uma fase estacionária seguida de uma recuperação do crescimento até uma segunda fase estacionária. Durante a primeira fase estacionária, a maior parte das células aumenta de tamanho e morre, mas as células remanescentes retornam à morfologia selvagem e seguem para a segunda fase de crescimento exponencial. Isso não acontece devido a mutações compensatórias, uma vez que células coletadas de pontos tardios da curva e diluídas em meio novo repetem este comportamento. Apesar de trabalhos com a linhagem PAO1 associarem σx à transcrição de oprF, que codifica a principal porina não específica de Pseudomonas, nas condições dos nossos ensaios em PA14 a expressão dessa porina não foi induzida pela superexpressão de σx. Assim, os efeitos observados nessa superexpressão também não podem ser atribuídos a OprF. A transcrição de oprF em PA14 mostrou-se majoritariamente dependente da região promotora a que se atribui a ligação de σ70, ao contrário dos relatos na literatura da dependência da região de ligação a σx. Análises proteômicas foram realizadas para investigar os elementos envolvidos nesses efeitos de superexpressão de σx, o que revelou a indução de diversas enzimas envolvidas na via de biossíntese de ácidos graxos. As células superexpressando σx apresentam uma maior proporção de ácidos hexadecanoico (C16) e hexadecenoico (C16:1) e dados de anisotropia mostram uma maior fluidez da(s) membrana(s). Este trabalho é o primeiro relato de um fator sigma ECF envolvido em biossíntese de lipídeos em P. aeruginosa.Pseudomonas aeruginosa is a very versatile gammaproteobacteria, able to colonize different environments and to infect phylogenetically distinct hosts, including immunocompromised humans. The extracytoplasmic function sigma factors (ECFs) are members of cell signaling systems (CSS), abundant in P. aeruginosa. Twenty genes coding for ECF sigma factors are present in the sequenced genomes of P. aeruginosa, most of them being part of TonB systems related to iron uptake. In this work, six poorly characterized sigma factors were overexpressed in strain PA14 from an arabinose inducible promoter to investigate their role in the expression of the two-component systems PvrSR and RcsCB, which regulates CupD fimbria, and their influence in P. aeruginosa cultures growth. None of the tested sigma factors led to two-component systems upregulation and overexpression of five of them caused no change in the growth profile, but pyocyanin production was altered in PA14_55550 overexpression and PA14_26600 and PA14_46810 overexpression led to a slight increase in biofilm initiation in PA14. By the other side, cultures overexpressing σx (ALB04) presented an altered lipopolysaccharide profile and a biphasic growth curve, reaching an early stationary phase followed by a growth resuming untill a second stationary phase. During the early stationary phase, most cells swells and dies, but the remaining cells return to wild type morphology and proceed to the second exponential phase of growth. This is not due to compensatory mutations, since cells collected from late points of the curve and diluted in fresh medium repeat this behavior. Although studies with strain PAO1 associate σx with transcription of oprF, encoding the major nonspecific porin of Pseudomonas, under our experiments conditions with PA14, this porin expression is not induced by σx overexpression. Thus, the effects observed in this overexpression cannot be attributed to OprF. Transcription of oprF in PA14 proved to be mainly controlled by the σ70-dependent promoter region instead of the σx-dependent promoter region reported in the literature. Proteomic analyses were performed to investigate the elements involved in these effects of σx overexpression, which revealed the induction of several enzymes involved in fatty acids biosynthesis. Cells overexpressing σx exhibit a greater proportion of hexadecanoic (C16) and hexadecenoic (C16: 1) acids and anisotropy data show higher fluidity of the membrane (s). This work is the first report of an ECF sigma factor involved in lipid biosynthesis in P. aeruginosa.
4
Roux, Nicolas. "Régulation du transfert de l' îlot de pathogénicité PAPI-1 chez Pseudomonas aeruginosa PA14". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4009.
Pełny tekst źródłaStreszczenie:
Les infections à Pseudomonas aeruginosa sont un problème de santé publique important et peu de solutions thérapeutiques sont disponibles face à des souches isolées multi-résistantes. Le séquençage de souches de P. aeruginosa a montré qu'en plus du génome cœur, il existe de nombreux gènes accessoires. La souche PA14 est un isolat clinique hautement virulent, de part la présence de deux îlots de pathogénicité, PAPI-1 et PAPI-2, contribuant de manière individuelle et synergique à la virulence. L'îlot PAPI-1, de 108 kb, est un élément intégratif et conjugatif (ICE), capable de s'auto-transférer à des souches de Pseudomonas par un mécanisme de conjugaison. Le mécanisme de transfert fait intervenir un pilus de type IVb encodé dans l'îlot PAPI-1.Mon travail de thèse a eu pour objectif d'identifier les régulateurs de ce locus pilPAPI-1. Ce travail a montré que ce locus est faiblement exprimé mais qu'il peut être induit par l'ajout d'acide caprique. Par une approche de mutagénèse aléatoire, j'ai démontré qu'il existe au moins deux gènes de fonctions inconnues présents dans PAPI-1 nécessaires à l'activation du locus et au transfert de l'îlot : RL103, qui coderait pour un régulateur transcriptionnel de type Ribbon-Helix-Helix (RHH) et RL102, qui coderait pour une protéine de partitionnement chromosomique. Par une approche transcriptomique, j'ai démontré que ces deux régulateurs sont aussi impliqués dans l'activation de l'expression de plus de 35% des gènes de PAPI-1. Dans leur ensemble, ces résultats ont mis en évidence que RL103 et RL102 sont deux activateurs du transfert de PAPI-1 et ont montré le premier exemple de régulateur de type RHH impliqué dans le transfert d'un ICEP. aeruginosa infections have become a serious threat to public health and are very difficult to treat due to the increasingly emergence of strains resistant to all known antibiotics. Sequencing of P. aeruginosa strains showed, that in addition to a conserved core genome, there are variable accessory genes. The PA14 strain is a highly virulent clinical and this is mainly due to two pathogenicity islands, PAPI-1 and PAPI-2, that contribute individually and synergistically to the virulence. The 108 kb PAPI-1 pathogenicity island is an integrative and conjugative element (ICE), capable of self-transferring to any recipient Pseudomonas strain by a conjugative mechanism. The transfer mechanism is mediated by a type IVb pilus, encoded within the PAPI-1 island. My PhD work was aimed to identifying the regulators of this pilPAPI-1 locus. This work showed that this locus is weakly expressed but may be induced by the addition of capric acid. Using a random mutagenesis approach, i have shown that there are at least two genes of unknown function (present in PAPI-1) necessary for activation of the locus pilPAPI-1 and the transfer of the island : RL103, which would encode a Ribbon Helix Helix-like transcriptional regulator and RL102, which would encode a partitioning chromosome protein. Using a transcriptomic approach with microarrays, I demonstrated that these two regulators are also involved in the activation of the expression of more than 35% of PAPI-1 genes. Taken together, these results show that Cpr and RL102 are two activators of the PAPI-1 transfer of PA14 and show the first example of a Ribbon-Helix-Helix transcriptional regulator involved in the transfer of an ICE
5
Torres, Naiara Utimura. "Estudo da ativação de biossíntese do polissacarídeo PEL na formação de biofilme de Pseudomonas aeruginosa PA14". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-18032016-155144/.
Pełny tekst źródłaStreszczenie:
Nos últimos anos, um estilo de vida celular vem ganhando destaque no mundo científico: o biofilme. O biofilme é uma comunidade celular em que as células permanecem aderidas a um substrato e envoltas em uma matriz de biopolímeros. Bactérias no estado de biofilme possuem algumas características alteradas, como o aumento da resistência a antibióticos e a facilidade de troca de genes de resistência, sendo um grande inconveniente na área médica e industrial. O patógeno humano Pseudomonas aeruginosa é uma bactéria gram-negativa causadora de infecções associadas a pacientes que apresentam o sistema imune debilitado, sendo muito comum em casos de fibrose cística. Além disso, P. aeruginosa é um organismo modelo no estudo de formação de biofilme, podendo produzir três tipos distintos de exopolissacarídeos: alginato, PSL e PEL. Devido ao pouco conhecimento do polissacarídeo PEL, a cepa P. aeruginosa PA14 vem sendo amplamente estudada, uma vez que essa é a única cepa em que PEL é o principal polímero responsável pela estabilidade da matriz de polissacarídeos. No processo de produção e exportação de PEL, sete proteínas são necessárias: Pel(A-G). Segundo predições computacionais e comparações com outros tipos de complexos biossintéticos de exopolissacarídeos, um modelo de arranjo molecular das proteínas Pel foi proposto, embora algumas proteínas não possuam uma função bem determinada no processo de síntese de PEL. Nesse contexto, o trabalho buscou estudar as proteínas envolvidas na formação de PEL para a melhor elucidação do mecanismo de ativação, produção e exportação desse polissacarídeo, com destaque para a enzima glicosiltransferase PelF e a investigação de uma possível interação de PelF com a proteína reguladora de produção do polissacarídeo, PelD, e a transportadora de membrana interna, PelG. Foram realizados diversos testes de interação entre PelF, PelG e construções solúveis de PelD por cromatografia de exclusão molecular, crosslinking e pull-down que não apresentaram interações entre tais construções, indicando que frações de membrana de PelD ou outros parceiros de interação podem ser necessários para a formação do complexo de síntese e exportação de PEL da membrana interna. Adicionalmente, mutantes de PelD sítio-dirigidos foram construídos em P. aeruginosa PA14 e tiveram sua capacidade de formação de biofilme avaliadas para investigação do mecanismo de ativação de PelD. A diminuição da formação de biofilme de mutantes de algumas regiões de PelD como a hélice S (resíduos 158-176), o core hidrofóbico ocupado pela hélice S e resíduos que estabilizam a ligação de c-di-GMP nos levou a propor um mecanismo de ativação desse importante regulador proteico de formação de biofilme em P. aeruginosa nunca descrito anteriormente.In the last years, a cellular lifestyle has been in the spotlight in the scientific world: the biofilm. Biofilm is a cellular community in which cells are attached to a substrate and surrounded by a biopolymeric matrix. Bacteria in a biofilm lifestyle has some altered characteristics, as a higher antibiotics tolerance and facility in resistance genes exchange, turning them into a big problem in medical and industrial fields. The human pathogen Pseudomonas aeruginosa is a gram-negative bacterium which causes infections associated to patients with an impaired immune system, as frequently found in patients with cystic fibrosis. Moreover, P. aeruginosa is a model organism in biofilm formation studies, producing three distinct types of exopolysaccharides: alginate, PSL and PEL. Since there is few information about PEL polysaccharide, the strain PA14 has been broadly studied because this is the unique strain in which PEL is the main polymer that gives stability of the polysaccharide matrix. In the process of PEL production and exportation, seven proteins are required: Pel(A-G). Computational predictions and comparison with other similar exopolysaccharides biosynthetic complexes led to a model of molecular complex of Pel proteins, though some proteins do not have a clear role in the PEL synthesis process. In this context, the work aimed to study the proteins related to PEL synthesis for a better understanding of the mechanism of production and exportation of this polysaccharide, focusing on the glycosyltransferase PelF and the investigation of its possible interaction with PelD, the regulatory protein of the polysaccharide production, and PelG, the putative inner membrane transporter. Several interaction assays were performed with PelF, PelG and soluble constructs of PelD using size exclusion chromatography, crosslinking and pull-down. No interaction was detected, showing that membrane fractions of PelD or other interaction partners can be required to the inner membrane complex of synthesis and export of PEL. Additionally, site-directed mutants of PelD in P. aeruginosa PA14 were constructed to evaluate their biofilm formation ability and investigate PelD activation mechanism. Mutants in regions as S-helix (residues 158-176), hydrophobic core occupied by the S-helix and residues of c-di-GMP stabilization presented a decrease of biofilm formation compared to the wild type strain. Those results allowed us to propose an activation mechanism of this important regulator of biofilm formation in P. aeruginosa never described before.
6
Adnan, Hazniza. "Studies on the activity of selected plants against biofilms of Pseudomonas aeruginosa strain PA14". Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25789.
Pełny tekst źródłaStreszczenie:
This thesis describes the activity of selected plants against biofilms of Pseudomonas aeruginosa strain PA14. The activity of plant extracts and subsequently purified compounds was evaluated using a stepwise separation process called bioassay-guided fractionation and used a microtitre plate based assay. Active extracts (showing more than 50 % biofilm inhibition, BFI) were further investigated for the presence of active compounds. The fractionation process involved the use of chromatographic techniques. Compounds were identified using NMR, GC-MS and LC-MS. Out of a total 129 extracts screened for antibiofilm activity using microtitre plate method, 44 extracts showed more than 50 % biofilm inhibition, whilst 85 extracts were found to increase biofilm formation. Four active extracts, (E333), (E341), (H338) and (M338) were selected for further investigation. A process of bioassay-guided fractionation was used to purify the phytochemicals present in each active extracts. This study led to the discovery of four bioactive compounds, namely (E333F1S1), (E341), (HA6) and (M338B) with antibiofilm activity against P. aeruginosa PA14. The active fraction (E333F1S1) from Ribes nigrum leaf was found to contain mixtures of alkanes such as n-nonadecane, 2-methylnonadecane, 2-methylicosane and 2 -methyloctacosane. The active extract of Sambucus nigra flower (E341) contained a mixture (2:1 ratio) of oleanolic and ursolic acid. Comparable activity was found at the same ratio (2:1) when these compounds were tested as a mixture of pure compounds. No significant difference (p < 0.05) in activity compared to a positive control was observed when these compounds were combined in different ratios. Only weak antibiofilm activity was observed when each compound was tested on its own. The LC-MS analysis on Coriandrum sativum seed active fractions, (HA6) revealed the presence of putative compounds such as 10-undecenal, dodecanal, 2-hexyl furan, linalool oxide, caryophyllene oxide and 4-ethylcamphor. When linalool oxide was tested, it exhibited a strong activity but reduced activity when in mixtures. Both activities were significantly different (p < 0.05) compared to positive control. Another active fraction of Coriandrum sativum seed, (M338B) showed the presence of putative compounds such as fatty acids, carboxylic acid, carboxylate and tetraone. This study led to the discovery of potential bioactive compounds from selected plant as antibiofilm agents against P. aeruginosa PA14. The bioactive compounds were from Ribes nigrum leaf (e.g. mixture of alkanes), Sambucus nigra flowers (e.g. mixture of ursolic acid and oleanolic acid) and Coriandrum sativum seeds (e.g. mixture of oxygenated monoterpenes, carboxylic acid, carboxylate, tetraone, glycerol, carbohydrates and fatty acids).
7
Abbes, Imen. "Protéome et lipidome de Pseudomonas aeruginosa PA14 cultivée en biofilm à l'interface air-liquide". Rouen, 2016. http://www.theses.fr/2016ROUES006.
Pełny tekst źródłaStreszczenie:
La formation des biofilms par Pseudomonas aeruginosa représente un problème majeur de santé public. A ce jour, la plupart des études concernait les biofilms formés à l’interface solideliquide (S-L). Cependant, très peu d'études se sont intéressées aux biofilms à l’interface air-liquide (pellicule). L’objectif de ce travail de thèse était de caractériser, par approches protéomiques et lipidomiques le mode de développement en pellicule chez P. Aeruginosa PA14. Dans un premier temps, nous avons caractérisé le protéome de P. Aeruginosa en pellicule et l’avons comparé à celui de cette bactérie cultivée en biofilm S-L et en planctonique. Nous avons mis en évidence la dépendance du protéome bactérien au mode de croissance et à la nature de l’interface colonisée. La croissance en pellicule favorise la sur-régulation de plusieurs facteurs de virulence, tandis que l'adaptation et la protection contre les conditions environnementales défavorables caractérise les bactéries cultivées en biofilm S-L. Dans un second temps, nous avons montré qu’en présence de tris(hydroxyméthyl)aminométhane (Tris), P. Aeruginosa est capable de synthétiser de nouveaux types de phospholipides dans lesquels le Tris est la fonction alcool du glycérophospholipide. La complexité de cette nouvelle composition phospholipidique diminue la résistance bactérienne envers l’action de plusieurs antibiotiques. Nous avons également montré la production de glucosaminylphosphatidylglycerol par P. Aeruginosa. Enfin, nous avons montré une altération de la composition en phospholipides lors du passage du mode de vie planctonique au mode de vie pellicule, composition qui est dépendante de l’âge du biofilmPseudomonas aeruginosa biofilms are a major problem in public health. To date, most studies concerned biofilms formed at the solid-liquid interface (S-L). However, very few studies have examined the biofilm at the air-liquid interface (pellicle). The objective of this thesis was to characterize, by proteomic and lipidomic approaches P. Aeruginosa PA14 in pellicle growth mode. Firstly, we characterized the proteome of P. Aeruginosa in pellicle and compared to that of their counterparts in S-L biofilm and in planktonic. We have highlighted the dependence of bacterial proteome to the growth mode and the nature of the colonized interface. Growth in pellicle promotes upregulation of several virulence factors, whereas adaptation and protection against detrimental environmental conditions characterizes bacteria in S-L biofilm. Secondly, we showed that in the presence of tris (hydroxymethyl)aminomethane (Tris), P. Aeruginosa is able to synthesize new types of phospholipids in which the Tris is the alcohol function in the glycerophospholipid. The complexity of this new phospholipid composition reduces bacterial resistance to several antibiotics action. We also showed the production of glucosaminylphosphatidylglycerol by P. Aeruginosa. Finally, we showed an alteration of phospholipid composition during the transition from planktonic to pellicle lifestyle. This composition is dependent on the biofilm age
8
Gaviard, Charlotte. "L'Effet " Modifications Post-Traductionnelles" : petits groupements chimiques, grandes conséquences? Caractérisation de protéines modifiées chez Pseudomonas aeruginosa PA14 par analyse protéomique". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR094.
Pełny tekst źródłaStreszczenie:
Pseudomonas aeruginosa PA14 est une bactérie pathogène très résistante aux antibiotiques et impliquée dans de nombreuses infections nosocomiales. Toutefois, la disponibilité d'agents antibactériens efficaces contre cette bactérie manque cruellement à ce jour. Explorer la physiologie de P. aeruginosa au niveau des modifications post-traductionnelles (PTMs) pourrait fortement contribuer au développement de nouveaux agents thérapeutiques. En effet, il a été montré certaines corrélations entre les PTMs et la virulence, l’adaptation et la résistance bactérienne. De plus, les progrès récents en protéomique ont permis d’accéder à un nombre croissant des protéines modifiées. Pourtant, leur description reste un véritable challenge.Dans une première partie, nous avons étudié l'impact des kinases et des phosphatases sur la physiologie de P. aeruginosa PA14. Cependant, aucune différence de phénotype n'a été observée entre les 8 mutants de ces enzymes et la souche sauvage.Dans une deuxième partie, nous avons caractérisé le succinylome et l'acétylome de la lysine chez P. aeruginosa PA14 dans quatre sources de carbone (glucose, citrate, succinate et glutamate) par enrichissement par anticorps couplé à la spectrométrie de masse. Ainsi, 1 530 sites succinylés (617 protéines) et 1 109 sites acétylés (526 protéines) ont été identifiés. De façon intéressante, 622 sites (312 protéines) ont été observés acétylés ou succinylés sur la même lysine, révélant ainsi l'existence de protéoformes pour une même protéine. Les protéines modifiées sont impliquées dans tous les processus biologiques. Toutefois, certaines d'entre elles ont des fonctions dans la résistance aux antibiotiques, le chimiotactisme et la virulence.Nous avons également quantifié les peptides succinylés et/ou acétylés dans les 4 sources de carbone. Les peptides succinylés étaient principalement sur-exprimés en citrate, mais aucune différence significative n’a été observée pour les peptides acétylées.Dans une troisième partie, nous avons étudié par immunoprécipitation le succinylome et l’acétylome de la lysine des protéines extracellulaire de P. aeruginosa. Nous avons montré que certaines lysines des protéines LasB et CbpD, deux facteurs de virulence, sont modifiées par 9 PTMs différentes. Une approche d’électrophorèse bi-dimensionnelle (2D) a permis de révéler et de quantifier les protéoformes des protéines extracellulaires et plus spécifiquement de ces facteurs de virulence.Dans une quatrième partie, une approche quantitative « label-free » a permis de mettre en avant 581 protéines qui varient différemment selon la source de carbone. Parmi ces protéines, 67 biomarqueurs ont été identifiés par approche statistique.Ces travaux constituent un point de départ prometteur pour de futures études sur le rôle de la succinylation de la lysine et d'autres PTMs chez P. aeruginosaPseudomonas aeruginosa PA14 is a multi-drug resistant human pathogen largely involved in nosocomial infections. Unfortunately, today, effective antibacterial agents lacked. Explore its physiology at the post-translational modification (PTMs) level may contribute to the renewal of combat tactics. Indeed, some correlations between PTMs and the bacterial virulence, adaptation and resistance have been shown. The recent improvements in proteomics have increased the number of modified proteins. However, their characterization believes a real challenge.In the first part, we focused on the impact of kinases and phosphatases on bacterial physiology of P. aeruginosa PA14. For this purpose, we compared different phenotypes of 8 mutants of kinase and phosphatase with the WT strain. Unfortunately, no difference was observed.In the second part, we characterized the lysine succinylome and acetylome in P. aeruginosa PA14 in 4 carbon sources (glucose, citrate, succinate and glutamate) by mass spectrometry. Overall, a total of 1 530 succinylated sites (617 proteins) and 1 109 acetylated sites (526 proteins) were identified. Interestingly, we noticed that 622 sites (312 proteins) can be either acetylated or succinylated on the same lysine. This reveals the existence of proteoforms for a same protein. As expected, many modified proteins are involved in a wide range of biological processes but some of these proteins have interesting functions like antibiotic resistance, chemotaxis and virulence.We also tried to quantify succinylated and/or acetylated peptides in the 4 carbon sources. Succinylated peptides were mainly over-represented in the citrate condition whereas no significant difference was observed for the acetylated forms.In the third part, we investigated the lysine succinylome and acetylome of P. aeruginosa in extracellular compartment by immunoprecipitation. We showed that some lysines of two virulence factors, LasB and CbpD, were modified by 9 different PTMs. We also used a 2-dimensional gel approach to reveal and quantify proteoforms of extracellular proteins and more specifically virulence factors. In the fourth part, we did a label-free quantitative approach to obtain protein abundance in each carbon source. In total, 581 proteins vary differently depending on the carbon source. Among these proteins, 67 biomarkers were identified by statistical approach.This work is a promising starting point for further investigations on the biological role of lysine succinylation, and others PTMs, in P. aeruginosa
9
Dangla, Pélissier Gauthier. "Identification et caractérisation des régulateurs du transfert horizontal de l’îlot de pathogénicité PAPI-1 chez Pseudomonas aeruginosa PA14". Thesis, Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0136.
Pełny tekst źródłaStreszczenie:
Le transfert horizontal d’ADN est un des moteurs importants de l’évolution. Par ce biais, les bactéries acquièrent de nouvelles voies métaboliques, résistent à de plus en plus de stress environnementaux et s’adaptent aux stratégies thérapeutiques. Chez P. aeruginosa PA14, l’îlot de pathogénicité majeur acquis par transfert horizontal est nommé PAPI-1. Cet îlot augmente considérablement la virulence de P. aeruginosa PA14. Cet îlot, appartenant à la famille des ICE, est capable de se transmettre de façon autonome au sein de l’espèce P. aeruginosa via une machinerie de conjugaison (SST4-GI) impliquant au moins 55 gènes encodés en son sein. Au cours de ma thèse, j’ai montré que l’H-NS MvaT réprime la biosynthèse du pilus conjugatif et que l’anti-H-NS NdpA2 encodé sur PAPI-1 lève cette inhibition afin que le facteur de régulation transcriptionnelle (FRT) TprA (encodé sur PAPI-1) puisse activer la synthèse du SST4-GI. J’ai montré que TprA régule également un changement de phénotype chez P. aeruginosa PA14 lié à l’induction de la majorité des gènes de l’ICE PAPI-1. Ces travaux ont été également l’occasion de caractériser le domaine régissant la spécificité de fixation des FRT de la famille RHH. En effet, la région N-terminale de ces FRT interagit spécifiquement avec l’ADN et leur confère leur spécificité de fixation. Enfin, à travers un crible de mutagénèse aléatoire, j’ai identifié ce qui semble être les prémices d’une cascade de régulation du transfert horizontal chez P. aeruginosa PA14Horizontal transfer of DNA is one of the major motors of evolutive forces. It allows bacteria to obtain extra biological functions such as new metabolic pathways, resistance factors against environmental stresses and adaption to therapeutic strategies. The opportunistic human pathogen P. aeruginosa PA14 is a gram-negative bacterium with a large genome plasticity partially due to genomic island acquisition. The major genomic acquisition is PAPI-1 which considerably increases the virulence potential of the PA14 strain. Indeed, a strain of P. aeruginosa without PAPI-1 is less infectious against various organisms. This genomic island, belonging to ICE family, is self-transmissible among P. aeruginosa species via a conjugative machinery (T4SS-GI) requiring at least 55 genes encoded within it. During my PhD, I proved that MvaT repress the conjugative pilus biosynthesis and that the anti-H-NS NdpA2 can release this repression to allow the transcriptional regulation factor (TRF) TprA to induce T4SS-GI synthesis. I also proved that TprA controls phenotype changes in P. aeruginosa PA14 through the regulation of the majority of PAPI-1 encoded genes. Through this work I also characterised the domain leading to the specificity of action of RHH family TRF. As a matter of fact, the N-terminal region of these TRF interacts directly with DNA leading their binding specificity. At last, by a random mutagenesis screening, I identified what seems to be a regulation cascade of horizontal transference in P. aeruginosa PA14
10
Nicastro, Gianlucca Gonçalves. "Efeito dos reguladores de resposta PvrR e RcsB na motilidade, formação de biofilme e sua relação com a fímbria CupD de Pseudomonas aeruginosa PA14". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-17062009-114537/.
Pełny tekst źródłaStreszczenie:
Pseudomonas aeruginosa é uma proteobactéria do grupo gama, que pode se comportar como um patógeno oportunista. A linhagem PA14 apresenta duas ilhas de patogenicidade. A maior delas, PAPI-1, contém dois grupos de genes envolvidos com virulência, transcritos de maneira oposta e que estão entre duas seqüências repetidas diretas. O primeiro grupo compreende quatro genes dispostos em dois operons, que codificam para proteínas de sistemas de dois componentes (PvrS, PvrR, RcsC e RcsB). PvrS e RcsC são proteínas sensoras híbridas, que apresentam domínios de histidina-quinase e de reguladores de resposta. PvrR é um regulador de resposta com um domínio EAL com atividade de fosfodiesterase de diGMP cíclico e RcsB apresenta um domínio de ligação a DNA, além de um domínio fosfoaceptor. O outro grupo é composto de cinco genes, cupD1 a cupD5, que codificam para uma fímbria do tipo chaperone-usher e que apresenta alta similaridade com cupA, envolvido na formação de biofilme em outras linhagens de P. aeruginosa. Trabalhos anteriores mostraram que pvrS, pvrR, rcsC, rcsB e cupD2 estão relacionados com a virulência de PA14. Como estes grupos de genes parecem ter sido inseridos na ilha em um único evento de recombinação, este trabalho investigou se os sistemas de dois componentes estão relacionados com a regulação da expressão de cupD. Foi observado que a expressão de cupD é maior a 28ºC do que que a 37ºC e é influenciada positivamente pelo regulador global de expressão, MvaT, uma proteína tipo H-NS. Ensaios de β-galactosidase a partir de uma fusão de transcrição mostraram que a atividade promotora de cupD é cerca de 50% menor numa linhagem com deleção em rcsB em relação à linhagem selvagem. Nenhuma diferença consistente foi observada entre as linhagens com deleções em pvrS, pvrR, rcsC e rcsB e PA14 em relação a motilidade dos tipos swarming, swimming ou twitching ou à formação de biofilme. A linhagem de P. aeruginosa PA14 superexpressando RcsB mostrou níveis exacerbados de mRNA de cupD1, sendo a atuação de RcsB específica em cupD, já que os outros grupos de genes cup presentes em PA14 não mostraram a mesma variação na expressão, conforme analisado por RT-PCR quantitativo. Essa linhagem mostrou também um aumento na formação de biofilme, sem que a motilidade fosse alterada. Ainda visando elucidar os mecanismos de regulação de cupD, linhagens que superexpressam pvrR também foram analisadas quanto a estes fenótipos. Nesse caso, a superexpressão de pvrR diminuiu a formação de biofilme, conforme esperado, aumentou a motilidade do tipo swarming, porém não alterou a expressão de cupD. Os dados do presente trabalho demonstraram que a cupD é regulado pelos genes do sistemas de dois componentes adjacentes a ele e que o ativador de transcrição RcsB está relacionado com a formação de biofilme em tubos de vidro, provavelmente via a fímbria CupD.Pseudomonas aeruginosa is a γ-proteobacteria that can behave as an opportunistic pathogen. The strain PA14 carries two pathogenicity islands, the largest of them, PAPI-1, contains two gene clusters between two direct repeat sequences that are transcribed in opposite directions and are involved in virulence. The first group consists of four genes arranged in two operons encoding two-component system proteins (PvrS, PvrR, RcsC and RcsB). PvrS and RcsC are hybrid sensor proteins, which contain domains of histidine kinase and response regulator domains. PvrR is a response regulator with a phosphodiesterase EAL domain and RcsB presents a C- terminal HTH DNA biding domain, in addition to a phosphoaceptor domain. The other group is composed of five genes, cupD1-5, that encodes components and assembly factors of a putative fimbrial CupD, which has high similarity with CupA, involved in the biofilm formation in other P. aeruginosa strains. Earlier work showed that pvrS, pvrR, rcsC, rcsB and cupD2 are related to the virulence of PA14. As these groups of genes appear to have been inserted on the island in a single event of recombination, this study investigated whether the two-component systems are related to the regulation of cupD expression. It was observed that cupD promoter activity is higher at 28oC than at 37oC and it is positively influenced by the global regulator, MvaT, a H-NS like protein. A lacZ transcriptional fusion showed about 50% less promoter activity of cupD from a strain with deletion in rcsB as compared to PA14. No consistent differences were found among the strains with deletions in pvrS, pvrR, rcsC and rcsB and PA14 on swarming, swimming and twitching motilities or biofilmsformation. A strain overexpressing overexpression showed heigher levels of cupD1mRNA of, and the role of RcsB as an activator is specific to cupD, as the other groups of cup genes present in PA14 did not show the same variation in the expression, as analyzed by quantitative RT-PCR. This strain also showed an increase in biofilm formation. In further assays aiming to elucidate the mechanisms of regulation of cupD, a strains overexpressing pvrR was also analyzed. Overexpression of pvrR decreased the formation of biofilm, as expected, and increased swarming motility, but did not alter the expression of cupD. The data from this study demonstrated that cupD is regulated by RcsB, and that this transcriptional activator is involved in the formation of biofilm in glass tubes, probably via CupD fimbriae.
Książki na temat "Pseudomonas aeruginosa PA14"
1
Okegbe, Chinweike. Connecting Cellular Redox State and Community Behavior in Pseudomonas aeruginosa PA14. [New York, N.Y.?]: [publisher not identified], 2016.
Znajdź pełny tekst źródłaCzęści książek na temat "Pseudomonas aeruginosa PA14"
1
Kirienko, Natalia V., Brent O. Cezairliyan, Frederick M. Ausubel i Jennifer R. Powell. "Pseudomonas aeruginosa PA14 Pathogenesis in Caenorhabditis elegans". W Methods in Molecular Biology, 653–69. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0473-0_50.
Pełny tekst źródła
2
Anna, L. M. Santa, G. V. Sebastian, N. Pereira, T. L. M. Alves, E. P. Menezes i D. M. G. Freire. "Production of Biosurfactant from a New and Promising Strain of Pseudomonas aeruginosa PA1". W Twenty-Second Symposium on Biotechnology for Fuels and Chemicals, 459–67. Totowa, NJ: Humana Press, 2001. http://dx.doi.org/10.1007/978-1-4612-0217-2_39.
Pełny tekst źródła