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stress response membrane bacteria

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https://www.readbyqxmd.com/read/29054003/adhesion-force-sensing-and-activation-of-a-membrane-bound-sensor-to-activate-nisin-efflux-pumps-in-staphylococcus-aureus-under-mechanical-and-chemical-stresses
#1
Vera Carniello, Akshay K Harapanahalli, Henk J Busscher, Henny C van der Mei
Nisin-associated-sensitivity-response-regulator (NsaRS) in Staphylococcus aureus is important for its adhesion to surfaces and resistance against antibiotics, like nisin. NsaRS consists of an intra-membrane-located sensor NsaS and a cytoplasmatically-located response-regulator NsaR, which becomes activated upon receiving phosphate groups from the intra-membrane-located sensor. HYPOTHESIS: The intra-membrane location of the NsaS sensor leads us to hypothesize that the two-component NsaRS system not only senses "chemical" (nisin) but also "mechanical" (adhesion) stresses to modulate efflux of antibiotics from the cytoplasm...
October 7, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29043249/interactions-between-bacteria-and-bile-salts-in-the-gastrointestinal-and-hepatobiliary-tracts
#2
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
#3
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/28933739/inoculation-with-azospirillum-sp-and-herbaspirillum-sp-bacteria-increases-the-tolerance-of-maize-to-drought-stress
#4
José Alfredo Curá, Diego Reinaldo Franz, Julián Ezequiel Filosofía, Karina Beatríz Balestrasse, Lautaro Exequiel Burgueño
Stress drought is an important abiotic factor that leads to immense losses in crop yields around the world. Strategies are urgently needed to help plants adapt to drought in order to mitigate crop losses. Here we investigated the bioprotective effects of inoculating corn grown under drought conditions with two types of plant growth-promoting rhizobacteria (PGPR), A. brasilense, strain SP-7, and H. seropedicae, strain Z-152. Plants inoculated with the bacteria were grown in a greenhouse with perlite as a substrate...
July 26, 2017: Microorganisms
https://www.readbyqxmd.com/read/28926236/biofilms-benefiting-plants-exposed-to-zno-and-cuo-nanoparticles-studied-with-a-root-mimetic-hollow-fiber-membrane
#5
Michelle Bonebrake, Kaitlyn Anderson, Jonathan Valiente, Astrid Jacobson, Joan E McLean, Anne Anderson, David W Britt
Plants exist with a consortium of microbes that influence plant health, including responses to biotic and abiotic stress. While nanoparticle (NP)-plant interactions are increasingly studied, the effect of NPs on the plant microbiome is less researched. Here a root-mimetic hollow fiber membrane (HFM) is presented for generating biofilms of plant-associated microbes nurtured by artificial root exudates (AREs) to correlate exudate composition with biofilm formation and response to NPs. Two microbial isolates from field-grown wheat, a bacillus endophyte and a pseudomonad root surface colonizer, were examined on HFMs fed with AREs varying in N and C composition...
October 2, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28925518/chemistry-of-peptidoglycan-in-mycobacterium-tuberculosis-life-style-an-off-the-wall-balance-of-synthesis-and-degradation
#6
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...
September 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922502/the-three-component-system-esrisr-regulates-a-cell-envelope-stress-response-in-corynebacterium-glutamicum
#7
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...
September 18, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28900441/bacillus-amyloliquefaciens-confers-tolerance-to-various-abiotic-stresses-and-modulates-plant-response-to-phytohormones-through-osmoprotection-and-gene-expression-regulation-in-rice
#8
Shalini Tiwari, Vivek Prasad, Puneet S Chauhan, Charu Lata
Being sessile in nature, plants have to withstand various adverse environmental stress conditions including both biotic and abiotic stresses. Comparatively, abiotic stresses such as drought, salinity, high temperature, and cold pose major threat to agriculture by negatively impacting plant growth and yield worldwide. Rice is one of the most widely consumed staple cereals across the globe, the production and productivity of which is also severely affected by different abiotic stresses. Therefore, several crop improvement programs are directed toward developing stress tolerant rice cultivars either through marker assisted breeding or transgenic technology...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28900025/psp-stress-response-proteins-form-a-complex-with-mislocalized-secretins-in-the-yersinia-enterocolitica-cytoplasmic-membrane
#9
Disha Srivastava, Amal Moumene, Josué Flores-Kim, Andrew J Darwin
The bacterial phage shock protein system (Psp) is a conserved extracytoplasmic stress response that is essential for the virulence of some pathogens, including Yersinia enterocolitica It is induced by events that can compromise inner membrane (IM) integrity, including the mislocalization of outer membrane pore-forming proteins called secretins. In the absence of the Psp system, secretin mislocalization permeabilizes the IM and causes rapid cell death. The Psp proteins PspB and PspC form an integral IM complex with two independent roles...
September 12, 2017: MBio
https://www.readbyqxmd.com/read/28894932/genomic-insights-into-temperature-dependent-transcriptional-responses-of-kosmotoga-olearia-a-deep-biosphere-bacterium-that-can-grow-from-20-to-79%C3%A2-%C3%A2-c
#10
Stephen M J Pollo, Abigail A Adebusuyi, Timothy J Straub, Julia M Foght, Olga Zhaxybayeva, Camilla L Nesbø
Temperature is one of the defining parameters of an ecological niche. Most organisms thrive within a temperature range that rarely exceeds ~30 °C, but the deep subsurface bacterium Kosmotoga olearia can grow over a temperature range of 59 °C (20-79 °C). To identify genes correlated with this flexible phenotype, we compared transcriptomes of K. olearia cultures grown at its optimal 65 °C to those at 30, 40, and 77 °C. The temperature treatments affected expression of 573 of 2224 K. olearia genes. Notably, this transcriptional response elicits re-modeling of the cellular membrane and changes in metabolism, with increased expression of genes involved in energy and carbohydrate metabolism at high temperatures and up-regulation of amino acid metabolism at lower temperatures...
September 11, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28890882/neutrophils-to-the-roscue-mechanisms-of-nadph-oxidase-activation-and-bacterial-resistance
#11
REVIEW
Giang T Nguyen, Erin R Green, Joan Mecsas
Reactive oxygen species (ROS) generated by NADPH oxidase play an important role in antimicrobial host defense and inflammation. Their deficiency in humans results in recurrent and severe bacterial infections, while their unregulated release leads to pathology from excessive inflammation. The release of high concentrations of ROS aids in clearance of invading bacteria. Localization of ROS release to phagosomes containing pathogens limits tissue damage. Host immune cells, like neutrophils, also known as PMNs, will release large amounts of ROS at the site of infection following the activation of surface receptors...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28865386/response-of-rhizobium-to-cd-exposure-a-volatile-perspective
#12
Paulo Cardoso, Magda Santos, Rosa Freitas, Sílvia M Rocha, Etelvina Figueira
The volatile metabolome of Rhizobium sp. strain E20-8 exposed to three concentrations of cadmium (2.5, 5.0 and 7.5 μM) was screened using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GC × GC-ToFMS), combined with headspace solid phase microextraction (HS-SPME). Cd exposure induced a global increase in the concentration of volatile organic compounds (VOCs) both intra and extracellularly. Peak areas of several linear alkanes, ketones, aldehydes, alcohols, terpenic and volatile sulfur compounds, and one ester (ethyl acetate), were especially increased when compared with the control condition (no Cd)...
August 30, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28864654/exogenous-polyunsaturated-fatty-acids-pufas-impact-membrane-remodeling-and-affect-virulence-phenotypes-among-pathogenic-vibrio-species
#13
Anna R Moravec, Andrew W Siv, Chelsea R Hobby, Emily N Lindsay, Layla V Norbash, Daniel J Shults, Steven J K Symes, David K Giles
The pathogenic Vibrio species (cholerae, parahaemolyticus and vulnificus) represent a constant threat to human health, causing food-borne and skin wound infections as a result of ingestion or exposure to contaminated water and seafood. Recent studies have highlighted Vibrio's ability to acquire fatty acids from environmental sources and assimilate them into cell membranes. The possession and conservation of such machinery provokes consideration of fatty acids as important factors in the pathogenic lifestyle of Vibrio species...
September 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28832155/pseudomonas-aeruginosa-proteome-under-hypoxic-stress-conditions-mimicking-the-cystic-fibrosis-lung
#14
Karthik Shantharam Kamath, Christoph Krisp, Joel Chick, Dana Pascovici, Steven P Gygi, Mark P Molloy
Pseudomonas aeruginosa is a ubiquitous Gram-negative pathogen known to inhabit hypoxic mucus plugs of cystic fibrosis (CF) patient lungs. Despite the high prevalence and related patient mortality, the protein machinery enabling the bacterium to adapt to low oxygen environment remains to be fully elucidated. We investigated this by performing both SWATH mass spectrometry and data-dependent SPS-MS3 of TMT-labeled peptides to profile the proteomes of two P. aeruginosa CF isolates, PASS2 and PASS3, and a laboratory reference strain, PAO1, grown under hypoxic stress (O2 < 1%) in media that mimic the nutrient components of the CF lung...
August 31, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28807687/influence-of-tween-80-on-the-production-and-structure-of-water-insoluble-curdlan-from-agrobacterium-sp
#15
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...
August 11, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28795780/pseudomonas-aeruginosa-defense-systems-against-microbicidal-oxidants
#16
Bastian Groitl, Jan-Ulrik Dahl, Jeremy W Schroeder, Ursula Jakob
The most abundant oxidants controlling bacterial colonization on mucosal barrier epithelia are hypochlorous acid (HOCl), hypobromous acid (HOBr) and hypothiocyanous acid (HOSCN). All three oxidants are highly antimicrobial but little is known about their relative efficacies, their respective cellular targets, or what specific responses they elicit in bacteria. To address these important questions, we directly tested the individual oxidants on the virulent Pseudomonas aeruginosa strain PA14. We discovered that HOCl and HOBr work almost interchangeably, impacting non-growing bacterial cultures more significantly than actively growing bacteria, and eliciting similar stress responses, including the heat shock response...
August 10, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28765539/bacterial-membrane-vesicles-transport-their-dna-cargo-into-host-cells
#17
Natalie J Bitto, Ross Chapman, Sacha Pidot, Adam Costin, Camden Lo, Jasmine Choi, Tanya D'Cruze, Eric C Reynolds, Stuart G Dashper, Lynne Turnbull, Cynthia B Whitchurch, Timothy P Stinear, Katryn J Stacey, Richard L Ferrero
Bacterial outer membrane vesicles (OMVs) are extracellular sacs containing biologically active products, such as proteins, cell wall components and toxins. OMVs are reported to contain DNA, however, little is known about the nature of this DNA, nor whether it can be transported into host cells. Our work demonstrates that chromosomal DNA is packaged into OMVs shed by bacteria during exponential phase. Most of this DNA was present on the external surfaces of OMVs, with smaller amounts located internally. The DNA within the internal compartments of Pseudomonas aeruginosa OMVs were consistently enriched in specific regions of the bacterial chromosome, encoding proteins involved in virulence, stress response, antibiotic resistance and metabolism...
August 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28760851/a-bacterial-stress-response-regulates-respiratory-protein-complexes-to-control-envelope-stress-adaptation
#18
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 bo3 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/28747041/influence-of-commercial-inactivated-yeast-derivatives-on-the-survival-of-probiotic-bacterium-lactobacillus-rhamnosus-hn001-in-an-acidic-environment
#19
Mingzhan Toh, Shao Quan Liu
This study evaluated the influence of three inactivated yeast derivatives (IYDs) used in wine production, namely OptiRed(®), OptiWhite(®) and Noblesse(®), on the viability of the probiotic strain Lactobacillus rhamnosus HN001 in an acidic environment. Addition of the IYDs at 3 g/L significantly enhanced the survival of the probiotic bacteria by 2.75-4.05 log cycles after 10-h exposure in a pH 3.0 buffer. Acid stress assay with IYD components obtained after centrifugation and filtration revealed that water-soluble compounds were responsible for improving the acid tolerance of L...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28741415/gram-negative-bacterial-membrane-vesicle-release-in-response-to-the-host-environment-different-threats-same-trick
#20
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...
July 25, 2017: Critical Reviews in Microbiology
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