Abstract Background Curli, cellulose and the cell surface protein BapA are matrix components in Salmonella biofilms. In this study we have investigated roles of these for morphology bacteria grown as colonies on agar plates within a biofilm submerged mica surfaces by applying atomic force microscopy (AFM) light microscopy. Results AFM imaging was performed Typhimurium 24 h biofilms 4, 8, 16 or slides standing cultures. Our data show that wild type curli were visible extracellular material...

The carbon storage regulator CsrA is an RNA binding protein that controls metabolism, biofilm formation and motility in various eubacteria. Nevertheless, Escherichia coli only five target mRNAs have been shown to be directly regulated by at the post-transcriptional level. Here we identified two new direct targets for CsrA, ycdT ydeH, both of which encode proteins with GGDEF domains. A csrA mutation caused mRNA levels ydeH increase more than 10-fold. mobility shift assays confirmed specific...

Bacterial survival depends on the ability to switch between sessile and motile lifestyles in response changing environmental conditions. In many species, this is governed by (3'-5')-cyclic-diguanosine monophosphate (c-di-GMP), a signalling molecule, which metabolized proteins containing GGDEF and/or EAL domains. Salmonella Typhimurium contains 20 such proteins. Here, we show that RNA-binding protein CsrA regulates expression of eight genes encoding GGDEF, GGDEF-EAL domain bound directly mRNA...

Spatial asymmetry is crucial to development. One mechanism for generating involves the localized synthesis of a key regulatory protein that diffuses away from its source, forming spatial gradient. Although gradients are prevalent in eukaryotes, at both tissue and intracellular levels, it unclear whether freely diffusible proteins can form within bacterial cells given their small size speed diffusion. Here, we show bacterium Caulobacter crescentus generates gradient active, phosphorylated...

Bacteria can arrest their own growth and proliferation upon nutrient depletion under various stressful conditions to ensure survival. However, the molecular mechanisms responsible for suppressing arresting cell cycle such remain incompletely understood. Here, we identify post-transcriptional that help enforce a cell-cycle in Caulobacter crescentus following limitation during entry into stationary phase by limiting accumulation of DnaA, conserved replication initiator protein. DnaA is rapidly...

Summary The rlrA genetic islet encodes an extracellular pilus in the Gram‐positive pathogen Streptococcus pneumoniae . Of three genes for structural subunits, rrgB major pilin, while rrgA and rrgC encode ancillary pilin subunits decorating shaft tip. Deletion of all pilus‐associated sortase genes, srtB , srtC srtD completely prevents biogenesis. Expression alone is sufficient to covalently associate RrgB one another as well linking RrgA adhesin RrgC subunit into polymer. active‐site cysteine...

All living cells are characterized by certain cell shapes and sizes. Many bacteria can change these properties depending on the growth conditions. The underlying mechanisms ecological relevance of changing shape size remain unclear in most cases. One bacterium that undergoes extensive shape-shifting response to conditions is freshwater Caulobacter crescentus When incubated for an extended time stationary phase, a subpopulation C. forms viable filamentous with helical shape. Here, we...

The bacterial cell cycle has been extensively studied under standard growth conditions. How it is modulated in response to environmental changes remains poorly understood. Here, we demonstrate that the freshwater bacterium Caulobacter crescentus blocks division and grows filamentous cells stress conditions affecting membrane. Our data suggest switches membrane-bound kinase CckA its phosphatase mode, leading rapid dephosphorylation, inactivation proteolysis of master regulator CtrA. clearance...

Summary The Clp family of proteases is responsible for controlling both stress responses and normal growth. In Caulobacter crescentus , the ClpXP protease essential drives cell cycle progression through adaptor‐mediated degradation. By contrast, physiological role ClpAP less well understood with only minor growth defects previously reported ΔclpA cells. Here, we show that plays an important in chromosome content fitness during extended Cells lacking ClpA accumulate aberrant numbers...

The carbon storage regulatory (Csr) system is a complex network controlling various phenotypes in many eubacteria. So far, the external conditions by which regulated are poorly understood. Here we show that expression of two noncoding small RNAs CsrB and CsrC Escherichia coli strongly increased cultures grown minimal medium. Addition tryptone, casamino acids or mixture amino to culture medium led rapid reduction levels CsrB. Based on this propose Csr sRNAs controlled acid availability growth

Hsp70 chaperones are well known for their important functions in maintaining protein homeostasis during thermal stress conditions. In many bacteria the homolog DnaK is also required growth absence of stress. The molecular reasons underlying essentiality remain most cases unclear. Here, we demonstrate that essential α-proteobacterium Caulobacter crescentus due to its regulatory function gene expression. Using a suppressor screen identified mutations allow DnaK. All reduced activity heat shock...

Summary All living cells must cope with protein aggregation, which occurs as a result of experiencing stress. In previously studied bacteria, aggregated is collected at the cell poles and retained throughout consecutive divisions only in old pole‐inheriting daughter cells, resulting aggregation‐free progeny within few generations. this study, we describe vivo kinetics aggregate formation elimination following heat antibiotic stress asymmetrically dividing bacterium Caulobacter crescentus ....

The Lon protease is a highly conserved protein degradation machine that has critical regulatory and quality control functions in cells from the three domains of life. Here, we report discovery α-proteobacterial heat shock protein, LarA, as dedicated regulator. We show LarA accumulates at onset proteotoxic stress allosterically activates Lon-catalysed large group substrates through five amino acid sequence its C-terminus. Further, find high levels cause growth inhibition Lon-dependent manner...

ABSTRACT The barA and uvrY genes of Escherichia coli encode a two-component sensor kinase response regulator, respectively. Although this system plays major role in the regulation central carbon metabolism, motility, biofilm formation by controlling expression CsrB CsrC noncoding RNAs, environmental conditions physiological signal(s) to which it responds remain obscure. In study, we explored effect external pH on activity BarA/UvrY. Our results indicate that lower than 5.5 provides an...

Abstract Background The Salmonella enterica BarA-SirA, the Erwinia carotovora ExpS-ExpA, Vibrio cholerae BarA-VarA and Pseudomonas spp GacS-GacA all belong to same orthologous family of two-component systems as Escherichia coli BarA-UvrY. In first four species it has been demonstrated that disruption this system leads a clear reduction in virulence bacteria. Our aim was determine if BarA-UvrY is connected with using monkey cystitis model. Results Cystitis generated Macaque fascularis monkeys...

The highly conserved protease Lon has important regulatory and protein quality control functions in cells from the three domains of life. Despite many years research on Lon, only a few specific substrates are known most organisms. Here, we used quantitative proteomics approach to identify novel dimorphic bacterium Caulobacter crescentus. We focused our study proteins involved polar cell differentiation investigated developmental regulator StaR flagella hook length FliK as detail. show that...

The Escherichia coli BarA-UvrY two-component system, which controls adaptation via the CsrB and CsrC sRNAs, is induced at entry of stationary phase by an unknown stimulus. Using a csrB-lacZ fusion, we demonstrated that factors RelA, SpoT LuxS, previously suggested to act on orthologues this have no role in induction. However, using transposon screen, identified hypothetical protein YhdA as new regulator expression. predicted be membrane-bound harbor GGDEF EAL domains, which, however, are...