The osmotic regulator OmpR is involved in the response of<i>Yersinia enterocolitica</i>O:9 to environmental stresses and survival within macrophages

Brzostek, Katarzyna; Raczkowska, Adrianna; Zasada, Aleksandra Anna

doi:10.1016/s0378-1097(03)00779-1

Cited by 50 publications

(56 citation statements)

References 30 publications

(49 reference statements)

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“…The effects of high osmolarity, oxidative stress, low pH, and high temperature were determined for strains of Y. pseudotuberculosis grown overnight in LB broth at 26°C and followed established protocols (12,22,44,72,73). For high-temperature stress experiments, stationaryphase cells were transferred to prewarmed tubes and incubated at 55°C for 5 min.…”

Section: Methodsmentioning

confidence: 99%

The Twin Arginine Translocation System Is Essential for Virulence ofYersinia pseudotuberculosis

et al. 2006

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Yersinia species pathogenic to humans have been extensively characterized with respect to type III secretion and its essential role in virulence. This study concerns the twin arginine translocation (Tat) pathway utilized by gram-negative bacteria to secrete folded proteins across the bacterial inner membrane into the periplasmic compartment. We have shown that the Yersinia Tat system is functional and required for motility and contributes to acid resistance. A Yersinia pseudotuberculosis mutant strain with a disrupted Tat system (tatC) was, however, not affected in in vitro growth or more susceptible to high osmolarity, oxidative stress, or high temperature, nor was it impaired in type III secretion. Interestingly, the tatC mutant was severely attenuated via both the oral and intraperitoneal routes in the systemic mouse infection model and highly impaired in colonization of lymphoid organs like Peyer's patches and the spleen. Our work highlights that Tat secretion plays a key role in the virulence of Y. pseudotuberculosis.As the integrity of the bacterial cytoplasm is protected by membranes, the necessity of means for transport of molecules between the bacterial compartments, periplasm and cytoplasm, and the surrounding milieu is obvious. Not only do bacteria require the ability to take up nutrients and get rid of waste, transport across the membranes is also highly involved in the ability of bacteria to cause disease. A number of specialized protein secretion systems are essential for delivery of virulence factors across the two membranes of gram-negative pathogens (39). The importance of these systems is reflected in the multitude of mechanisms that have evolved not only for protein translocation across the bacterial membranes but also for targeting of anti-host factors across the host cell membrane. The means of translocation across the bacterial outer membrane have been grouped into five different pathways

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Section: Methodsmentioning

confidence: 99%

The Twin Arginine Translocation System Is Essential for Virulence ofYersinia pseudotuberculosis

et al. 2006

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“…In unactivated J774.1 macrophages, there was a 30-fold increase in the number of bacteria obtained 25 h postinfection (29). Also, another study reported a 110-fold increase in bacteria recovered from infected J774 macrophages at 24 h postinfection (7). While the role of intracellular survival remains poorly understood in the context of Y. enterocolitica pathogenesis, it is possible that YspM, similar to SseJ, may play a role in that process.…”

Section: Discussionmentioning

confidence: 98%

YspM, a Newly Identified Ysa Type III Secreted Protein ofYersinia enterocolitica

Witowski¹,

Walker²,

Miller

2008

J Bacteriol

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Yersinia enterocolitica has three type three secretion systems, the flagellar, the plasmid Ysc type III secretion system (T3SS), and the chromosomal Ysa T3SS. The Ysc T3SS, through the proteins it secretes (Yops), prevents phagocytosis of Y. enterocolitica and is required for disease processes in the mouse host. Recent data demonstrate a role for the Ysa T3SS during initial colonization of the mouse via secretion of Ysps (Yersinia secreted proteins). This work characterizes the discovery of a newly identified Ysa type III secreted protein, YspM. Expression of yspM is regulated by temperature, NaCl concentration, and other known regulators of the ysa system. In addition, YspM is translocated into host cells via the Ysa T3SS. YspM is homologous to proteins classified as GDSL bacterial lipases, which possess a catalytic triad of amino acids (Ser, Asp, and His) located in three of five blocks of amino acid identity. Sequence analysis of the JB580v strain of Y. enterocolitica shows that, due to a premature stop codon, it no longer encodes the fifth block of amino acid identity containing the predicted catalytic histidine. However, seven other biotype 1B strains sequenced did possess the domain. A functional difference between the forms was revealed when YspM was expressed in Saccharomyces cerevisiae. Yeast growth was uninhibited when YspM from JB580v was expressed but greatly inhibited when YspM from Y295 (YspM Y295 ) was expressed. Site-directed mutagenesis of the histidine of YspM Y295 ablated the toxic effects. These results indicate that YspM is secreted by the Ysa T3SS and that, possibly due to lipase activity, it targets eukaryotic cellular component(s).

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“…An additional, simple explanation may be provided by the selective deregulation of genes common (1) not necessarily princeps publication (2) Pseudogene in CO92, but not in KIM. Ogino et al, 1998;Brzostek et al 2003;Hirakawa et al 2003;Masuda and Church, 2002;Shin and Park, 1995. to both species. This will be discussed below through one example.…”

Section: Two-component Systems: Trying To Reassemble the Puzzlementioning

confidence: 97%

“…Acquisition of chromosomal fragments of exogenous origin (predicted to have been a frequent occurrence) can hardly account for this dramatic evolution either, since it is thought that all the known fragments were acquired prior to Y. pestis speciation (Hinchliffe et al, 2003). An additional, simple explanation may be provided by the selective deregulation of genes common Brzostek et al 2003;Hirakawa et al 2003;Masuda and Church, 2002;Shin and Park, 1995. to both species. This will be discussed below through one example.…”

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confidence: 99%

Transcriptional Regulation inYersinia: An UpdateYersinia: An Update

2005

Current Issues in Molecular Biology

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In response to the ever-present need to adapt to environmental stress, bacteria have evolved complex (and often overlapping) regulatory networks that respond to various changes in growth conditions, including entry into the host. The expression of most bacterial virulence factors is regulated; thus the question of how bacteria orchestrate this process has become a recurrent research theme for every bacterial pathogen, and the three pathogenic Yersinia are no exception. The earliest studies of regulation in these species were prompted by the characterization of plasmid-encoded virulence determinants, and those conducted since have continued to focus on the principal aspects of virulence in these pathogens. Most Yersinia virulence factors are thermally regulated, and are active at either 28°C (the optimal growth temperature) or 37°C (the host temperature). However, regulation by this omnipresent thermal stimulus occurs through a wide variety of mechanisms, which generally act in conjunction with (or are modulated by) additional controls for other environmental cues such as pH, ion concentration, nutrient availability, osmolarity, oxygen tension and DNA damage. Yersinia's recent entry into the genome sequencing era has given scientists the opportunity to study these regulators on a genome-wide basis. This has prompted the first attempts to establish links between the presence or absence of regulatory elements and the three pathogenic species' respective lifestyles and degrees of virulence. IntroductionCompared to cells of multicellular organisms, microorganisms face a significant additional challenge: they encounter a wide array of sudden, intense and sometimes even life-threatening environmental changes, and must therefore rapidly modify their structure and metabolism accordingly. Although other mechanisms exist, these changes in bacterial physiology mainly occur by regulating the production of the appropriate structural proteins and enzymes. Adaptation of gene expression in response to such situations appears to be essential for bacterial survival, and thus the regulators involved in these processes should be treated as being as important as the effectors themselves. In bacterial pathogens like those of the Yersinia genus, most outside-to-inside stressinduced responses lead to changes in the expression of virulence factors. In fact, most of the known Yersinia virulence genes are regulated, and elements controlling their expression are thus also virulence factors.All regulatory systems have a common purpose: to create an interface between the perception of one or several stimuli and to activate or repress expression of their cognate effectors. As we will see by reviewing what is known about Yersinia, the means used to regulate the production of a given bacterial factor range from very simple mechanisms (where the DNA-binding properties of the transcriptional regulator are directly altered by the stimulus) to extremely complex systems which sometimes require lengthy signal transduction cascades and/or simul...

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The osmotic regulator OmpR is involved in the response ofYersinia enterocoliticaO:9 to environmental stresses and survival within macrophages

Cited by 50 publications

References 30 publications

The Twin Arginine Translocation System Is Essential for Virulence ofYersinia pseudotuberculosis

The Twin Arginine Translocation System Is Essential for Virulence ofYersinia pseudotuberculosis

YspM, a Newly Identified Ysa Type III Secreted Protein ofYersinia enterocolitica

Transcriptional Regulation inYersinia: An UpdateYersinia: An Update

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