scholarly journals Self-Regulation and Interplay of Rsm Family Proteins Modulate the Lifestyle of Pseudomonas putida

2016 ◽  
Vol 82 (18) ◽  
pp. 5673-5686 ◽  
Author(s):  
Óscar Huertas-Rosales ◽  
María Isabel Ramos-González ◽  
Manuel Espinosa-Urgel

ABSTRACTIn the plant-beneficial bacteriumPseudomonas putidaKT2440, three genes have been identified that encode posttranscriptional regulators of the CsrA/RsmA family. Their regulatory roles in the motile and sessile lifestyles ofP. putidahave been investigated by generating single-, double-, and triple-null mutants and by overexpressing each protein (RsmA, RsmE, and RsmI) in different genetic backgrounds. Thersmtriple mutant shows reduced swimming and swarming motilities and increased biofilm formation, whereas overexpression of RsmE or RsmI results in reduced bacterial attachment. However, biofilms formed on glass surfaces by the triple mutant are more labile than those of the wild-type strain and are easily detached from the surface, a phenomenon that is not observed on plastic surfaces. Analysis of the expression of adhesins and exopolysaccharides in the different genetic backgrounds suggests that the biofilm phenotypes are due to alterations in the composition of the extracellular matrix and in the timing of synthesis of its elements. We have also studied the expression patterns of Rsm proteins and obtained data that indicate the existence of autoregulation mechanisms.IMPORTANCEProteins of the CsrA/RsmA family function as global regulators in different bacteria. More than one of these proteins is present in certain species. In this study, all of the RsmA homologs inP. putidaare characterized and globally taken into account to investigate their roles in controlling bacterial lifestyles and the regulatory interactions among them. The results offer new perspectives on how biofilm formation is modulated in this environmentally relevant bacterium.

2014 ◽  
Vol 80 (22) ◽  
pp. 7053-7060 ◽  
Author(s):  
Helen L. Brown ◽  
Mark Reuter ◽  
Louise J. Salt ◽  
Kathryn L. Cross ◽  
Roy P. Betts ◽  
...  

ABSTRACTThe bacterial pathogenCampylobacter jejuniis primarily transmitted via the consumption of contaminated foodstuffs, especially poultry meat. In food processing environments,C. jejuniis required to survive a multitude of stresses and requires the use of specific survival mechanisms, such as biofilms. An initial step in biofilm formation is bacterial attachment to a surface. Here, we investigated the effects of a chicken meat exudate (chicken juice) onC. jejunisurface attachment and biofilm formation. Supplementation of brucella broth with ≥5% chicken juice resulted in increased biofilm formation on glass, polystyrene, and stainless steel surfaces with fourC. jejuniisolates and oneC. coliisolate in both microaerobic and aerobic conditions. When incubated with chicken juice,C. jejuniwas both able to grow and form biofilms in static cultures in aerobic conditions. Electron microscopy showed thatC. jejunicells were associated with chicken juice particulates attached to the abiotic surface rather than the surface itself. This suggests that chicken juice contributes toC. jejunibiofilm formation by covering and conditioning the abiotic surface and is a source of nutrients. Chicken juice was able to complement the reduction in biofilm formation of an aflagellated mutant ofC. jejuni, indicating that chicken juice may support food chain transmission of isolates with lowered motility. We provide here a useful model for studying the interaction ofC. jejunibiofilms in food chain-relevant conditions and also show a possible mechanism forC. jejunicell attachment and biofilm initiation on abiotic surfaces within the food chain.


2013 ◽  
Vol 79 (13) ◽  
pp. 4166-4169
Author(s):  
Wanjun Zhang ◽  
Huhe ◽  
Yuanbai Pan ◽  
Masanori Toyofuku ◽  
Nobuhiko Nomura ◽  
...  

ABSTRACTLapA is the largest surface adhesion protein ofPseudomonas putidathat initiates biofilm formation. Here, by using transposon insertion mutagenesis and a conditionallapAmutant, we demonstrate for the first time that LapA influences chloral hydrate (CH) dechlorination inP. putidaLF54.


mSystems ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Iman Chouikha ◽  
Daniel E. Sturdevant ◽  
Clayton Jarrett ◽  
Yi-Cheng Sun ◽  
B. Joseph Hinnebusch

ABSTRACTYersinia pestis, the etiologic agent of plague, emerged as a fleaborne pathogen only within the last 6,000 years. Just five simple genetic changes in theYersinia pseudotuberculosisprogenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropodborne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performedin vivotranscriptional profiling ofY. pestis, aY. pseudotuberculosiswild-type strain (unable to form biofilm in the flea foregut), and aY. pseudotuberculosismutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious blood meal. Surprisingly, theY. pseudotuberculosismutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change the expression levels of thehmsgenes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. TheY. pseudotuberculosismutant uniquely expressed much higher levels ofYersiniatype VI secretion system 4 (T6SS-4) in the flea, and this locus was required for flea blockage byY. pseudotuberculosisbut not for blockage byY. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing-related genes, transcription regulation genes, and stress response genes were evident during flea infection.IMPORTANCEY. pestisemerged as a highly virulent, arthropod-transmitted pathogen on the basis of relatively few and discrete genetic changes fromY. pseudotuberculosis. Parallel comparisons of thein vitroandin vivotranscriptomes ofY. pestisand twoY. pseudotuberculosisvariants that produce a nontransmissible infection and a transmissible infection of the flea vector, respectively, provided insights into howY. pestishas adapted to life in its flea vector and point to evolutionary changes in the regulation of metabolic and biofilm development pathways in these two closely related species.


2020 ◽  
Vol 86 (21) ◽  
Author(s):  
Nataliya A. Teteneva ◽  
Sergey V. Mart’yanov ◽  
María Esteban-López ◽  
Jörg Kahnt ◽  
Timo Glatter ◽  
...  

ABSTRACT In most ecosystems, bacteria exist primarily as structured surface-associated biofilms that can be highly tolerant to antibiotics and thus represent an important health issue. Here, we explored drug repurposing as a strategy to identify new antibiofilm compounds, screening over 1,000 compounds from the Prestwick Chemical Library of approved drugs for specific activities that prevent biofilm formation by Escherichia coli. Most growth-inhibiting compounds, which include known antibacterial but also antiviral and other drugs, also reduced biofilm formation. However, we also identified several drugs that were biofilm inhibitory at doses where only a weak effect or no effect on planktonic growth could be observed. The activities of the most specific antibiofilm compounds were further characterized using gene expression analysis, proteomics, and microscopy. We observed that most of these drugs acted by repressing genes responsible for the production of curli, a major component of the E. coli biofilm matrix. This repression apparently occurred through the induction of several different stress responses, including DNA and cell wall damage, and homeostasis of divalent cations, demonstrating that biofilm formation can be inhibited through a variety of molecular mechanisms. One tested drug, tyloxapol, did not affect curli expression or cell growth but instead inhibited biofilm formation by suppressing bacterial attachment to the surface. IMPORTANCE The prevention of bacterial biofilm formation is one of the major current challenges in microbiology. Here, by systematically screening a large number of approved drugs for their ability to suppress biofilm formation by Escherichia coli, we identified a number of prospective antibiofilm compounds. We further demonstrated different mechanisms of action for individual compounds, from induction of replicative stress to disbalance of cation homeostasis to inhibition of bacterial attachment to the surface. Our work demonstrates the potential of drug repurposing for the prevention of bacterial biofilm formation and suggests that also for other bacteria, the activity spectrum of antibiofilm compounds is likely to be broad.


2013 ◽  
Vol 79 (13) ◽  
pp. 3967-3973 ◽  
Author(s):  
Shannon M. Hinsa-Leasure ◽  
Cassandra Koid ◽  
James M. Tiedje ◽  
Janna N. Schultzhaus

ABSTRACTPsychrobacter arcticusstrain 273-4, an isolate from a Siberian permafrost core, is capable of forming biofilms when grown in minimal medium under laboratory conditions. Biofilms form at 4 to 22°C when acetate is supplied as the lone carbon source and with 1 to 7% sea salt.P. arcticusis also capable of colonizing quartz sand. Transposon mutagenesis identified a gene important for biofilm formation byP. arcticus. Four transposon mutants were mapped to a 20.1-kbp gene, which is predicted to encode a protein of 6,715 amino acids (Psyc_1601). We refer to this open reading frame ascat1, for cold attachment gene 1. Thecat1mutants are unable to form biofilms at levels equivalent to that of the wild type, and there is no impact on the planktonic growth characteristics of the strains, indicating a specific role in biofilm formation. Through time course studies of the static microtiter plate assay, we determined thatcat1mutants are unable to form biofilms equivalent to that of the wild type under all conditions tested. In flow cell experiments,cat1mutants initially are unable to attach to the surface. Over time, however, they form microcolonies, an architecture very different from that produced by wild-type biofilms. Our results demonstrate that Cat1 is involved in the initial stages of bacterial attachment to surfaces.


2012 ◽  
Vol 78 (17) ◽  
pp. 6217-6224 ◽  
Author(s):  
Thomas Baumgarten ◽  
Stefanie Sperling ◽  
Jana Seifert ◽  
Martin von Bergen ◽  
Frank Steiniger ◽  
...  

ABSTRACTAmong the adaptive responses of bacteria to rapid changes in environmental conditions, those of the cell envelope are known to be the most crucial. Therefore, several mechanisms with which bacteria change their cell surface and membranes in the presence of different environmental stresses have been elucidated. Among these mechanisms, the release of outer membrane vesicles (MV) in Gram-negative bacteria has attracted particular research interest because of its involvement in pathogenic processes, such as that ofPseudomonas aeruginosabiofilm formation in cystic fibrosis lungs. In this study, we investigated the role of MV formation as an adaptive response ofPseudomonas putidaDOT-T1E to several environmental stress factors and correlated it to the formation of biofilms. In the presence of toxic concentrations of long-chain alcohols, under osmotic stress caused by NaCl, in the presence of EDTA, and after heat shock, cells of this strain released MV within 10 min in the presence of a stressor. The MV formed showed similar size and charge properties, as well as comparable compositions of proteins and fatty acids. MV release caused a significant increase in cell surface hydrophobicity, and an enhanced tendency to form biofilms was demonstrated in this study. Therefore, the release of MV as a stress response could be put in a physiological context.


2009 ◽  
Vol 71-73 ◽  
pp. 175-178 ◽  
Author(s):  
Mario A. Vera ◽  
Thore Rohwerder ◽  
Soeren Bellenberg ◽  
Wolfgang Sand ◽  
Y. Denis ◽  
...  

Bioleaching is the extraction of metals, such as copper or gold, from ore by microorganisms. Bacterial attachment increases leaching activities due to the formation of a "reaction space" between the metal sulfide surface and the cell. This process depends on abiotic characteristics such as purity and degree of crystallization of the metal sulfide, as well as biotic ones such as the capacity of the bacteria for detecting favourable attachment sites and synthesizing a suitable cell envelope (EPS), for adhesion. Planktonic and sessile cells should differ significantly in their metabolic activities and therefore in their gene expression patterns. To help to understand At. ferrooxidans biofilm formation, microarray transcript profiling was carried out to compare planktonic and sessile cells. The high contents of EPS and ferric iron of the biofilms are interfering with RNA extraction, causing inhibition of DNAse, reverse transcriptase and/or polymerase activities required to get labelled target cDNA. In order to have sufficient high quality RNA suitable for transcriptomic analysis, we have optimized the biofilm formation of At. ferrooxidans on pyrite (FeS2) and the RNA extraction from the sessile cell population. DNA microarrays have been hybridized with labelled cDNAs from sessile and planktonic cells and preliminary data suggest that some genes are differently expressed between these two subpopulations. The understanding of these differences may help us to shift populations of leaching bacteria from the planktonic state towards the sessile state in order to influence bioleaching.


2011 ◽  
Vol 77 (18) ◽  
pp. 6733-6736 ◽  
Author(s):  
Reiko Yamamoto ◽  
Yuichiro Noiri ◽  
Mikiyo Yamaguchi ◽  
Yoko Asahi ◽  
Hazuki Maezono ◽  
...  

ABSTRACTChronological gene expression patterns of biofilm-forming cells are important to understand bioactivity and pathogenicity of biofilms. ForPorphyromonas gingivalisATCC 33277 biofilm formation, the number of genes differentially regulated by more than 1.5-fold was highest during the growth stage (312/2,090 genes), and some pathogen-associated genes were time-dependently controlled.


2013 ◽  
Vol 79 (8) ◽  
pp. 2703-2712 ◽  
Author(s):  
Lillian C. Hsu ◽  
Jean Fang ◽  
Diana A. Borca-Tasciuc ◽  
Randy W. Worobo ◽  
Carmen I. Moraru

ABSTRACTAttachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, includingEscherichia coli,Listeria innocua, andPseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.


2003 ◽  
Vol 71 (12) ◽  
pp. 7154-7158 ◽  
Author(s):  
A. M. Prouty ◽  
J. S. Gunn

ABSTRACT In this study, the roles of global regulators, motility, lipopolysaccharide, and exopolysaccharides were further characterized with respect to biofilm formation on both gallstones and glass surfaces. These studies show the complex nature of biofilms and demonstrate that characteristics observed for each biofilm are unique to the particular culture condition.


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