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stress response membrane envelope bacteria

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https://www.readbyqxmd.com/read/28674071/-major-tom-to-ground-control-how-lipoproteins-communicate-extra-cytoplasmic-stress-to-the-decision-center-of-the-cell
#1
Géraldine Laloux, Jean-François Collet
The envelope of bacteria is a complex multi-layered shield that ensures multiple essential functions, including protecting the cell from external assaults. Hence, bacterial cells have evolved intricate mechanisms, called envelope stress response systems (ESRS), to monitor all kinds of perturbations affecting the integrity of their envelope and mount an appropriate response to contain or repair the damage. In the model bacterium Escherichia coli, several ESRS are built around a two-component system, in which envelope stress triggers a phosphotransfer between a sensor protein in the inner membrane of the envelope and a response regulator in the cytoplasm...
July 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28588134/the-rcs-regulated-colanic-acid-capsule-maintains-membrane-potential-in-salmonella-enterica-serovar-typhimurium
#2
Jasmine M Pando, Joyce E Karlinsey, Jimmie C Lara, Stephen J Libby, Ferric C Fang
The Rcs phosphorelay and Psp (phage shock protein) systems are envelope stress responses that are highly conserved in gammaproteobacteria. The Rcs regulon was found to be strongly induced during metal deprivation of Salmonella enterica serovar Typhimurium lacking the Psp response. Nineteen genes activated by the RcsA-RcsB response regulator make up an operon responsible for the production of colanic acid capsular polysaccharide, which promotes biofilm development. Despite more than half a century of research, the physiological function of colanic acid has remained elusive...
June 6, 2017: MBio
https://www.readbyqxmd.com/read/28513097/evidence-for-a-peptidoglycan-like-structure-in-orientia-tsutsugamushi
#3
Sharanjeet Atwal, Suparat Giengkam, Suwittra Chaemchuen, Jack Dorling, Nont Kosaisawe, Michael VanNieuwenhze, Somponnat Sampattavanich, Peter Schumann, Jeanne Salje
Bacterial cell walls are composed of the large cross-linked macromolecule peptidoglycan, which maintains cell shape and is responsible for resisting osmotic stresses. This is a highly conserved structure and the target of numerous antibiotics. Obligate intracellular bacteria are an unusual group of organisms that have evolved to replicate exclusively within the cytoplasm or vacuole of a eukaryotic cell. They tend to have reduced amounts of peptidoglycan, likely due to the fact that their growth and division takes place within an osmotically protected environment, and also due to a drive to reduce activation of the host immune response...
May 17, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28467057/conditional-chaperone-client-interactions-revealed-by-genetically-encoded-photo-cross-linkers
#4
Shuai Zhang, Dan He, Zhi Lin, Yi Yang, Haiping Song, Peng R Chen
The cell envelope is an integral and essential component of Gram-negative bacteria. As the front line during host-pathogen interactions, it is directly challenged by host immune responses as well as other harsh extracellular stimuli. The high permeability of the outer-membrane and the lack of ATP energy system render it difficult to maintain important biological activities within the periplasmic space under stress conditions. The HdeA/B chaperone machinery is the only known acid resistant system found in bacterial periplasm, enabling enteric pathogens to survive through the highly acidic human stomach and establish infections in the intestine...
May 3, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28439041/cues-from-the-membrane-bacterial-glycerophospholipids
#5
Zachary D Dalebroux
In this issue of the Journal of Bacteriology, V. W. Rowlett et al. unveil new Escherichia coli circuitry linking membrane glycerophospholipid (GPL) homeostasis to bacterial stress response and adaptation mechanisms (J Bacteriol 199:e00849-16, 2017, https://doi.org/10.1128/JB.00849-16). Glycerophospholipids comprise critical components of the dual-membrane envelope of Gram-negative bacteria and participate in many processes. The new evidence suggests that, in some instances, distinct E. coli GPL molecules function for distinct biochemistry and bacteria sense perturbations in membrane GPL concentrations to coordinate survival strategies...
July 1, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28439040/impact-of-membrane-phospholipid-alterations-in-escherichia-coli-on-cellular-function-and-bacterial-stress-adaptation
#6
Veronica W Rowlett, Venkata K P S Mallampalli, Anja Karlstaedt, William Dowhan, Heinrich Taegtmeyer, William Margolin, Heidi Vitrac
Bacteria have evolved multiple strategies to sense and rapidly adapt to challenging and ever-changing environmental conditions. The ability to alter membrane lipid composition, a key component of the cellular envelope, is crucial for bacterial survival and adaptation in response to environmental stress. However, the precise roles played by membrane phospholipids in bacterial physiology and stress adaptation are not fully elucidated. The goal of this study was to define the role of membrane phospholipids in adaptation to stress and maintenance of bacterial cell fitness...
July 1, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28416660/redefining-the-essential-trafficking-pathway-for-outer-membrane-lipoproteins
#7
Marcin Grabowicz, Thomas J Silhavy
The outer membrane (OM) of Gram-negative bacteria is a permeability barrier and an intrinsic antibiotic resistance factor. Lipoproteins are OM components that function in cell wall synthesis, diverse secretion systems, and antibiotic efflux pumps. Moreover, each of the essential OM machines that assemble the barrier requires one or more lipoproteins. This dependence is thought to explain the essentiality of the periplasmic chaperone LolA and its OM receptor LolB that traffic lipoproteins to the OM. However, we show that in strains lacking substrates that are toxic when mislocalized, both LolA and LolB can be completely bypassed by activating an envelope stress response without compromising trafficking of essential lipoproteins...
May 2, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28408482/small-regulatory-bacterial-rnas-regulating-the-envelope-stress-response
#8
REVIEW
Gracjana Klein, Satish Raina
Most bacteria encode a large repertoire of RNA-based regulatory mechanisms. Recent discoveries have revealed that the expression of many genes is controlled by a plethora of base-pairing noncoding small regulatory RNAs (sRNAs), regulatory RNA-binding proteins and RNA-degrading enzymes. Some of these RNA-based regulated processes respond to stress conditions and are involved in the maintenance of cellular homeostasis. They achieve it by either direct posttranscriptional repression of several mRNAs, including blocking access to ribosome and/or directing them to RNA degradation when the synthesis of their cognate proteins is unwanted, or by enhanced translation of some key stress-regulated transcriptional factors...
April 15, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/28030630/system-wide-adaptations-of-desulfovibrio-alaskensis-g20-to-phosphate-limited-conditions
#9
Tanja Bosak, Florence Schubotz, Ana de Santiago-Torio, Jennifer V Kuehl, Hans K Carlson, Nicki Watson, Mirna Daye, Roger E Summons, Adam P Arkin, Adam M Deutschbauer
The prevalence of lipids devoid of phosphorus suggests that the availability of phosphorus limits microbial growth and activity in many anoxic, stratified environments. To better understand the response of anaerobic bacteria to phosphate limitation and starvation, this study combines microscopic and lipid analyses with the measurements of fitness of pooled barcoded transposon mutants of the model sulfate reducing bacterium Desulfovibrio alaskensis G20. Phosphate-limited G20 has lower growth rates and replaces more than 90% of its membrane phospholipids by a mixture of monoglycosyl diacylglycerol (MGDG), glycuronic acid diacylglycerol (GADG) and ornithine lipids, lacks polyphosphate granules, and synthesizes other cellular inclusions...
2016: PloS One
https://www.readbyqxmd.com/read/27865622/protecting-from-envelope-stress-variations-on-the-phage-shock-protein-theme
#10
REVIEW
Riccardo Manganelli, Maria Laura Gennaro
During envelope stress, critical inner-membrane functions are preserved by the phage-shock-protein (Psp) system, a stress response that emerged from work with Escherichia coli and other Gram-negative bacteria. Reciprocal regulatory interactions and multiple effector functions are well documented in these organisms. Searches for the Psp system across phyla reveal conservation of only one protein, PspA. However, examination of Firmicutes and Actinobacteria reveals that PspA orthologs associate with non-orthologous regulatory and effector proteins retaining functions similar to those in Gram-negative counterparts...
November 16, 2016: Trends in Microbiology
https://www.readbyqxmd.com/read/27821607/novel-rpos-dependent-mechanisms-strengthen-the-envelope-permeability-barrier-during-stationary-phase
#11
Angela M Mitchell, Wei Wang, Thomas J Silhavy
Gram-negative bacteria have effective methods of excluding toxic compounds, including a largely impermeable outer membrane (OM) and a range of efflux pumps. Furthermore, when cells become nutrient limited, RpoS enacts a global expression change providing cross-protection against many stresses. Here, we utilized sensitivity to an anionic detergent (sodium dodecyl sulfate [SDS]) to probe changes occurring to the cell's permeability barrier during nutrient limitation. Escherichia coli is resistant to SDS whether cells are actively growing, carbon limited, or nitrogen limited...
January 15, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/27790614/antimicrobial-activity-of-cationic-antimicrobial-peptides-against-gram-positives-current-progress-made-in-understanding-the-mode-of-action-and-the-response-of-bacteria
#12
REVIEW
Soraya Omardien, Stanley Brul, Sebastian A J Zaat
Antimicrobial peptides (AMPs) have been proposed as a novel class of antimicrobials that could aid the fight against antibiotic resistant bacteria. The mode of action of AMPs as acting on the bacterial cytoplasmic membrane has often been presented as an enigma and there are doubts whether the membrane is the sole target of AMPs. Progress has been made in clarifying the possible targets of these peptides, which is reported in this review with as focus gram-positive vegetative cells and spores. Numerical estimates are discussed to evaluate the possibility that targets, other than the membrane, could play a role in susceptibility to AMPs...
2016: Frontiers in Cell and Developmental Biology
https://www.readbyqxmd.com/read/27720009/the-journey-of-lipoproteins-through-the-cell-one-birthplace-multiple-destinations
#13
REVIEW
J Szewczyk, J-F Collet
Bacterial lipoproteins are a very diverse group of proteins characterized by the presence of an N-terminal lipid moiety that serves as a membrane anchor. Lipoproteins have a wide variety of crucial functions, ranging from envelope biogenesis to stress response. In Gram-negative bacteria, lipoproteins can be targeted to various destinations in the cell, including the periplasmic side of the cytoplasmic or outer membrane, the cell surface or the external milieu. The sorting mechanisms have been studied in detail in Escherichia coli, but exceptions to the rules established in this model bacterium exist in other bacteria...
2016: Advances in Microbial Physiology
https://www.readbyqxmd.com/read/27698088/interactions-between-the-cytoplasmic-domains-of-pspb-and-pspc-silence-the-yersinia-enterocolitica-phage-shock-protein-response
#14
Josué Flores-Kim, Andrew J Darwin
The phage shock protein (Psp) system is a widely conserved cell envelope stress response that is essential for the virulence of some bacteria, including Yersinia enterocolitica Recruitment of PspA by the inner membrane PspB-PspC complex characterizes the activated state of this response. The PspB-PspC complex has been proposed to be a stress-responsive switch, changing from an OFF to an ON state in response to an inducing stimulus. In the OFF state, PspA cannot access its binding site in the C-terminal cytoplasmic domain of PspC (PspC(CT)), because this site is bound to PspB...
December 15, 2016: Journal of Bacteriology
https://www.readbyqxmd.com/read/27645386/transcriptional-responses-of-escherichia-coli-to-a-small-molecule-inhibitor-of-lolcde-an-essential-component-of-the-lipoprotein-transport-pathway
#15
Christian Lorenz, Thomas J Dougherty, Stephen Lory
In Gram-negative bacteria, a dedicated machinery consisting of LolABCDE components targets lipoproteins to the outer membrane. We used a previously identified small-molecule inhibitor of the LolCDE complex of Escherichia coli to assess the global transcriptional consequences of interference with lipoprotein transport. Exposure of E. coli to the LolCDE inhibitor at concentrations leading to minimal and significant growth inhibition, followed by transcriptome sequencing, identified a small group of genes whose transcript levels were decreased and a larger group whose mRNA levels increased 10- to 100-fold compared to those of untreated cells...
December 1, 2016: Journal of Bacteriology
https://www.readbyqxmd.com/read/27620730/adaptive-response-of-rhodococcus-opacus-pwd4-to-salt-and-phenolic-stress-on-the-level-of-mycolic-acids
#16
Carla C C R de Carvalho, Martin A Fischer, Sandra Kirsten, Birgit Würz, Lukas Y Wick, Hermann J Heipieper
Mycolata form a group of Gram-positive bacteria with unique cell envelope structures that are known for their high tolerance against antibiotics and both aromatic and aliphatic hydrocarbons. An important part of the unique surface structure of the mycolata is the presence of long chain α-alkyl-β-hydroxy fatty acids, the mycolic acids. In order to investigate the adaptive changes in the mycolic acid composition, we investigated the composition of mycolic acids during the response both to osmotic stress caused by NaCl and to 4-chlorophenol in Rhodococcus opacus PWD4...
December 2016: AMB Express
https://www.readbyqxmd.com/read/27406567/lps-remodeling-triggers-formation-of-outer-membrane-vesicles-in-salmonella
#17
Wael Elhenawy, Michael Bording-Jorgensen, Ezequiel Valguarnera, M Florencia Haurat, Eytan Wine, Mario F Feldman
UNLABELLED: Outer membrane vesicles (OMV) are proposed to mediate multiple functions during pathogenesis and symbiosis. However, the mechanisms responsible for OMV formation remain poorly understood. It has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. Based on these studies, we formulated the hypothesis that lipid A deacylation might impose shape modifications that result in the curvature of the outer membrane (OM) and subsequent OMV formation...
July 12, 2016: MBio
https://www.readbyqxmd.com/read/26909555/transcriptional-profiling-of-coxiella-burnetii-reveals-extensive-cell-wall-remodeling-in-the-small-cell-variant-developmental-form
#18
Kelsi M Sandoz, David L Popham, Paul A Beare, Daniel E Sturdevant, Bryan Hansen, Vinod Nair, Robert A Heinzen
A hallmark of Coxiella burnetii, the bacterial cause of human Q fever, is a biphasic developmental cycle that generates biologically, ultrastructurally, and compositionally distinct large cell variant (LCV) and small cell variant (SCV) forms. LCVs are replicating, exponential phase forms while SCVs are non-replicating, stationary phase forms. The SCV has several properties, such as a condensed nucleoid and an unusual cell envelope, suspected of conferring enhanced environmental stability. To identify genetic determinants of the LCV to SCV transition, we profiled the C...
2016: PloS One
https://www.readbyqxmd.com/read/26908573/fine-tuning-of-the-cpx-envelope-stress-response-is-required-for-cell-wall-homeostasis-in-escherichia-coli
#19
Antoine Delhaye, Jean-François Collet, Géraldine Laloux
UNLABELLED: The envelope of Gram-negative bacteria is an essential compartment that constitutes a protective and permeability barrier between the cell and its environment. The envelope also hosts the cell wall, a mesh-like structure made of peptidoglycan (PG) that determines cell shape and provides osmotic protection. Since the PG must grow and divide in a cell-cycle-synchronized manner, its synthesis and remodeling are tightly regulated. Here, we discovered that PG homeostasis is intimately linked to the levels of activation of the Cpx system, an envelope stress response system traditionally viewed as being involved in protein quality control in the envelope...
February 23, 2016: MBio
https://www.readbyqxmd.com/read/26901131/bacillus-subtilis-extracytoplasmic-function-ecf-sigma-factors-and-defense-of-the-cell-envelope
#20
REVIEW
John D Helmann
Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σ(W) is most closely associated with membrane-active agents, σ(X) with cationic antimicrobial peptide resistance, and σ(V) with resistance to lysozyme. Here, I highlight the role of the σ(M) regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes...
April 2016: Current Opinion in Microbiology
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