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stress response membrane envelope bacteria

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https://www.readbyqxmd.com/read/29992897/small-regulatory-rnas-in-the-enterobacterial-response-to-envelope-damage-and-oxidative-stress
#1
Kathrin S Fröhlich, Susan Gottesman
The ability of bacteria to thrive in diverse habitats and to adapt to ever-changing environmental conditions relies on the rapid and stringent modulation of gene expression. It has become evident in the past decade that small regulatory RNAs (sRNAs) are central components of networks controlling the bacterial responses to stress. Functioning at the posttranscriptional level, sRNAs base-pair with cognate mRNAs to alter translation, stability, or both to either repress or activate the targeted transcripts; the RNA chaperone Hfq participates in stabilizing sRNAs and in promoting pairing between target and sRNA...
July 2018: Microbiology Spectrum
https://www.readbyqxmd.com/read/29914989/ompr-regulator-of-burkholderia-multivorans-controls-mucoid-to-nonmucoid-transition-and-other-cell-envelope-properties-associated-with-persistence-in-the-cystic-fibrosis-lung
#2
Inês N Silva, Filipa D Pessoa, Marcelo J Ramires, Mário R Santos, Jörg D Becker, Vaughn S Cooper, Leonilde M Moreira
Bacteria from the Burkholderia cepacia complex grow in different natural and man-made environments and are feared opportunistic pathogens that cause chronic respiratory infections in cystic fibrosis patients. Previous studies showed that Burkholderia mucoid clinical isolates grown under stress conditions give rise to nonmucoid variants devoid of the exopolysaccharide cepacian. Here, we have determined that a major cause of the nonmucoid morphotype involves nonsynonymous mutations and small indels in the ompR gene encoding a response regulator of a two-component regulatory system...
June 18, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29894683/synthetic-antimicrobial-peptides-delocalize-membrane-bound-proteins-thereby-inducing-a-cell-envelope-stress-response
#3
Soraya Omardien, Jan W Drijfhout, Henk van Veen, Soraya Schachtschabel, Martijn Riool, Leendert W Hamoen, Stanley Brul, Sebastian A J Zaat
BACKGROUND: Three amphipathic cationic antimicrobial peptides (AMPs) were characterized by determining their effect on Gram-positive bacteria using Bacillus subtilis strain 168 as a model organism. These peptides were TC19 and TC84, derivatives of thrombocidin-1 (TC-1), the major AMPs of human blood platelets, and Bactericidal Peptide 2 (BP2), a synthetic designer peptide based on human bactericidal permeability increasing protein (BPI). METHODS: To elucidate the possible mode of action of the AMPs we performed a transcriptomic analysis using microarrays...
June 9, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29717015/regulation-of-flagellum-biosynthesis-in-response-to-cell-envelope-stress-in-salmonella-enterica-serovar-typhimurium
#4
Imke Spöring, Sebastian Felgner, Matthias Preuße, Denitsa Eckweiler, Manfred Rohde, Susanne Häussler, Siegfried Weiss, Marc Erhardt
Flagellum-driven motility of Salmonella enterica serovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population of Salmonella , resulting in flagellated and nonflagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4 C2 with respect to proteolytic degradation...
May 1, 2018: MBio
https://www.readbyqxmd.com/read/29488183/variations-on-a-theme-evolution-of-the-phage-shock-protein-system-in-actinobacteria
#5
Janani Ravi, Vivek Anantharaman, L Aravind, Maria Laura Gennaro
The phage shock protein (Psp) stress-response system protects bacteria from envelope stress through a cascade of interactions with other proteins and membrane lipids to stabilize the cell membrane. A key component of this multi-gene system is PspA, an effector protein that is found in diverse bacterial phyla, archaea, cyanobacteria, and chloroplasts. Other members of the Psp system include the cognate partners of PspA that are part of known operons: pspF||pspABC in Proteobacteria, liaIHGFSR in Firmicutes, and clgRpspAMN in Actinobacteria...
May 2018: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/29458656/stress-responses-outer-membrane-permeability-control-and-antimicrobial-resistance-in-enterobacteriaceae
#6
Sushovan Dam, Jean-Marie Pagès, Muriel Masi
Bacteria have evolved several strategies to survive a myriad of harmful conditions in the environment and in hosts. In Gram-negative bacteria, responses to nutrient limitation, oxidative or nitrosative stress, envelope stress, exposure to antimicrobials and other growth-limiting stresses have been linked to the development of antimicrobial resistance. This results from the activation of protective changes to cell physiology (decreased outer membrane permeability), resistance transporters (drug efflux pumps), resistant lifestyles (biofilms, persistence) and/or resistance mutations (target mutations, production of antibiotic modification/degradation enzymes)...
March 2018: Microbiology
https://www.readbyqxmd.com/read/29450619/immediate-response-mechanisms-of-gram-negative-solvent-tolerant-bacteria-to-cope-with-environmental-stress-cis-trans-isomerization-of-unsaturated-fatty-acids-and-outer-membrane-vesicle-secretion
#7
REVIEW
Christian Eberlein, Thomas Baumgarten, Stephan Starke, Hermann J Heipieper
Bacteria have evolved an array of adaptive mechanisms enabling them to survive and grow in the presence of different environmental stresses. These mechanisms include either modifications of the membrane or changes in the overall energy status, cell morphology, and cell surface properties. Long-term adaptations are dependent on transcriptional regulation, the induction of anabolic pathways, and cell growth. However, to survive sudden environmental changes, bacterial short-term responses are essential to keep the cells alive after the occurrence of an environmental stress factor such as heat shock or the presence of toxic organic solvents...
March 2018: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29414707/analyzing-thermal-stability-of-cell-membrane-of-salmonella-using-time-multiplexed-impedance-sensing
#8
Aida Ebrahimi, Laszlo N Csonka, Muhammad A Alam
Heat treatment is one of the most widely used methods for inactivation of bacteria in food products. Heat-induced loss of bacterial viability has been variously attributed to protein denaturation, oxidative stress, or membrane leakage; indeed, it is likely to involve a combination of these processes. We examine the effect of mild heat stress (50-55°C for ≤12 min) on cell permeability by directly measuring the electrical conductance of samples of Salmonella enterica serovar Typhimurium to answer a fundamental biophysical question, namely, how bacteria die under mild heat stress...
February 6, 2018: Biophysical Journal
https://www.readbyqxmd.com/read/29211019/dual-regulation-of-the-small-rna-micc-and-the-quiescent-porin-ompn-in-response-to-antibiotic-stress-in-escherichia-coli
#9
Sushovan Dam, Jean-Marie Pagès, Muriel Masi
Antibiotic resistant Gram-negative bacteria are a serious threat for public health. The permeation of antibiotics through their outer membrane is largely dependent on porin, changes in which cause reduced drug uptake and efficacy. Escherichia coli produces two major porins, OmpF and OmpC. MicF and MicC are small non-coding RNAs (sRNAs) that modulate the expression of OmpF and OmpC, respectively. In this work, we investigated factors that lead to increased production of MicC. micC promoter region was fused to lacZ , and the reporter plasmid was transformed into E...
December 6, 2017: Antibiotics
https://www.readbyqxmd.com/read/29043249/interactions-between-bacteria-and-bile-salts-in-the-gastrointestinal-and-hepatobiliary-tracts
#10
REVIEW
Verónica Urdaneta, Josep Casadesús
Bile salts and bacteria have intricate relationships. The composition of the intestinal pool of bile salts is shaped by bacterial metabolism. In turn, bile salts play a role in intestinal homeostasis by controlling the size and the composition of the intestinal microbiota. As a consequence, alteration of the microbiome-bile salt homeostasis can play a role in hepatic and gastrointestinal pathological conditions. Intestinal bacteria use bile salts as environmental signals and in certain cases as nutrients and electron acceptors...
2017: Frontiers in Medicine
https://www.readbyqxmd.com/read/29022867/response-to-photo-oxidative-stress-of-pseudomonas-aeruginosa-pao1-mutants-impaired-in-different-functions
#11
Viviana Teresa Orlandi, Fabrizio Bolognese, Eleonora Martegani, Vincenzo Cantaluppi, Claudio Medana, Paola Barbieri
Clinicians often have to deal with infections that are difficult to control because they are caused by superbugs resistant to many antibiotics. Alternatives to antibiotic treatment include antimicrobial photodynamic therapy (aPDT). The photodynamic process causes bacterial death, inducing oxidative stress through the photoactivation of photosensitizer molecules in the presence of oxygen. No PDT-resistant bacteria have been selected to date, thus the response to photo-oxidative stress in non-phototrophic bacteria needs further investigation...
October 12, 2017: Microbiology
https://www.readbyqxmd.com/read/28925518/chemistry-of-peptidoglycan-in-mycobacterium-tuberculosis-life-cycle-an-off-the-wall-balance-of-synthesis-and-degradation
#12
REVIEW
Flavia Squeglia, Alessia Ruggiero, Rita Berisio
The cell wall envelope of mycobacteria is structurally distinct from that of both Gram-positive and Gram-negative bacteria. In Mycobacterium tuberculosis, this cell wall has unique structural features and plays a crucial role in drug resistance and macrophage survival under stress conditions. Peptidoglycan is the major constituent of this cell wall, with an important structural role, giving structural strength, and counteracting the osmotic pressure of the cytoplasm. Synthesis of this complex polymer takes place in three stages that occur at three different locations in the cell, from the cytoplasm to the external side of the cell membrane, where polymerization occurs...
February 21, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922502/the-three-component-system-esrisr-regulates-a-cell-envelope-stress-response-in-corynebacterium-glutamicum
#13
Britta Kleine, Ava Chattopadhyay, Tino Polen, Daniela Pinto, Thorsten Mascher, Michael Bott, Melanie Brocker, Roland Freudl
When the cell envelope integrity is compromised, bacteria trigger signaling cascades resulting in the production of proteins that counteract these extracytoplasmic stresses. Here, we show that the two-component system EsrSR regulates a cell envelope stress response in the Actinobacterium Corynebacterium glutamicum. The sensor kinase EsrS possesses an amino-terminal phage shock protein C (PspC) domain, a property that sets EsrSR apart from all other two-component systems characterized so far. An integral membrane protein, EsrI, whose gene is divergently transcribed to the esrSR gene locus and which interestingly also possesses a PspC domain, acts as an inhibitor of EsrSR under non-stress conditions...
December 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28807687/influence-of-tween-80-on-the-production-and-structure-of-water-insoluble-curdlan-from-agrobacterium-sp
#14
Ying Liang, Li Zhu, Minjie Gao, Zhiyong Zheng, Jianrong Wu, Xiaobei Zhan
In order to explore the mechanism by which Tween-80 enhances the production of curdlan produced by Agrobacterium sp., the effects of Tween-80 on the production and structure of curdlan and Agrobacterium sp. were evaluated. Maximum curdlan production (51.94g/L) was achieved when 16g/L Tween-80 was added at the beginning of the cell growth stage. The addition of Tween-80 at higher concentration inhibited cell growth. However, the addition of 16g/L Tween-80 enhanced the production of curdlan with a looser ultrastructure, significantly weakened the envelopment of curdlan on Agrobacterium sp...
January 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28760851/a-bacterial-stress-response-regulates-respiratory-protein-complexes-to-control-envelope-stress-adaptation
#15
Randi L Guest, Junshu Wang, Julia L Wong, Tracy L Raivio
The Cpx envelope stress response mediates adaptation to stresses that affect protein folding within the envelope of Gram-negative bacteria. Recent transcriptome analyses revealed that the Cpx response impacts genes that affect multiple cellular functions predominantly associated with the cytoplasmic membrane. In this study, we examined the connection between the Cpx response and the respiratory complexes NADH dehydrogenase I and cytochrome bo 3 in enteropathogenic Escherichia coli We found that the Cpx response directly represses the transcription of the nuo and cyo operons and that Cpx-mediated repression of these complexes confers adaptation to stresses that compromise envelope integrity...
October 15, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28741415/gram-negative-bacterial-membrane-vesicle-release-in-response-to-the-host-environment-different-threats-same-trick
#16
Charlotte Volgers, Paul H M Savelkoul, Frank R M Stassen
Bacteria are confronted with a multitude of stressors when occupying niches within the host. These stressors originate from host defense mechanisms, other bacteria during niche competition or result from physiological challenges such as nutrient limitation. To counteract these stressors, bacteria have developed a stress-induced network to mount the adaptations required for survival. These stress-induced adaptations include the release of membrane vesicles from the bacterial envelope. Membrane vesicles can provide bacteria with a plethora of immediate and ultimate benefits for coping with environmental stressors...
May 2018: Critical Reviews in Microbiology
https://www.readbyqxmd.com/read/28674071/major-tom-to-ground-control-how-lipoproteins-communicate-extracytoplasmic-stress-to-the-decision-center-of-the-cell
#17
REVIEW
Géraldine Laloux, Jean-François Collet
The envelope of bacteria is a complex multilayered 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 to 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...
November 1, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28588134/the-rcs-regulated-colanic-acid-capsule-maintains-membrane-potential-in-salmonella-enterica-serovar-typhimurium
#18
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
#19
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...
August 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28467057/conditional-chaperone-client-interactions-revealed-by-genetically-encoded-photo-cross-linkers
#20
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
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