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stress response membrane bacteria

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https://www.readbyqxmd.com/read/28611746/adaptations-to-high-salt-in-a-halophilic-protist-differential-expression-and-gene-acquisitions-through-duplications-and-gene-transfers
#1
Tommy Harding, Andrew J Roger, Alastair G B Simpson
The capacity of halophiles to thrive in extreme hypersaline habitats derives partly from the tight regulation of ion homeostasis, the salt-dependent adjustment of plasma membrane fluidity, and the increased capability to manage oxidative stress. Halophilic bacteria, and archaea have been intensively studied, and substantial research has been conducted on halophilic fungi, and the green alga Dunaliella. By contrast, there have been very few investigations of halophiles that are phagotrophic protists, i.e., protozoa...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28607072/adaptor-protein-mediates-dynamic-pump-assembly-for-bacterial-metal-efflux
#2
Ace George Santiago, Tai-Yen Chen, Lauren A Genova, Won Jung, Alayna M George Thompson, Megan M McEvoy, Peng Chen
Multicomponent efflux complexes constitute a primary mechanism for Gram-negative bacteria to expel toxic molecules for survival. As these complexes traverse the periplasm and link inner and outer membranes, it remains unclear how they operate efficiently without compromising periplasmic plasticity. Combining single-molecule superresolution imaging and genetic engineering, we study in living Escherichia coli cells the tripartite efflux complex CusCBA of the resistance-nodulation-division family that is essential for bacterial resistance to drugs and toxic metals...
June 12, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28604884/ferrous-iron-efflux-systems-in-bacteria
#3
REVIEW
Hualiang Pi, John D Helmann
Bacteria require iron for growth, with only a few reported exceptions. In many environments, iron is a limiting nutrient for growth and high affinity uptake systems play a central role in iron homeostasis. However, iron can also be detrimental to cells when it is present in excess, particularly under aerobic conditions where its participation in Fenton chemistry generates highly reactive hydroxyl radicals. Recent results have revealed a critical role for iron efflux transporters in protecting bacteria from iron intoxication...
June 12, 2017: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/28593794/cthtra-the-lynchpin-of-the-chlamydial-surface-and-a-promising-therapeutic-target
#4
James W Marsh, Vanissa A Ong, William B Lott, Peter Timms, Joel DA Tyndall, Wilhelmina M Huston
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection worldwide and the leading cause of preventable blindness. Reports have emerged of treatment failure, suggesting a need to develop new antibiotics to battle Chlamydia infection. One possible candidate for a new treatment is the protease inhibitor JO146, which is an effective anti-Chlamydia agent that targets the CtHtrA protein. CtHtrA is a lynchpin on the chlamydial cell surface due to its essential and multifunctional roles in the bacteria's stress response, replicative phase of development, virulence and outer-membrane protein assembly...
June 8, 2017: Future Microbiology
https://www.readbyqxmd.com/read/28592862/identification-of-unique-cardiolipin-and-monolysocardiolipin-species-in-acinetobacter-baumannii
#5
Patrizia Lopalco, Julia Stahl, Cosimo Annese, Beate Averhoff, Angela Corcelli
Acidic glycerophospholipids play an important role in determining the resistance of Gram-negative bacteria to stress conditions and antibiotics. Acinetobacter baumannii, an opportunistic human pathogen which is responsible for an increasing number of nosocomial infections, exhibits broad antibiotic resistances. Here lipids of A. baumannii have been analyzed by combined MALDI-TOF/MS and TLC analyses; in addition GC-MS analyses of fatty acid methyl esters released by methanolysis of membrane phospholipids have been performed...
June 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28588134/the-rcs-regulated-colanic-acid-capsule-maintains-membrane-potential-in-salmonella-enterica-serovar-typhimurium
#6
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/28552524/resveratrol-induces-membrane-and-dna-disruption-via-pro-oxidant-activity-against-salmonella-typhimurium
#7
Wonjong Lee, Dong Gun Lee
Resveratrol is a flavonoid found in various plants including grapes, which has been reported to be active against various pathogenic bacteria. However, antibacterial effects and mechanisms via pro-oxidant property of resveratrol remain unknown and speculative. This research investigated antibacterial mechanism of resveratrol against a food-borne human pathogen Salmonella typhimurium, and confirmed the cell death associated oxidative damage. Resveratrol increased outer membrane permeability and membrane depolarization...
May 25, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28537416/glutathione-degradation
#8
Anand K Bachhawat, Amandeep Kaur
SIGNIFICANCE: Glutathione degradation has for long been thought to occur only on non-cytosolic pools. This is because there has been only one enzyme known to degrade glutathione (γ-glutamyltranspeptidase), and this localizes to either the plasma membrane (mammals, bacteria) or the vacuolar membrane (yeast, plants) and acts on extracellular or vacuolar pools. The last few years has seen the discovery of several new enzymes of glutathione degradation that function in the cytosol, throwing new light on glutathione degradation...
May 24, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28526842/revealing-genome-scale-transcriptional-regulatory-landscape-of-ompr-highlights-its-expanded-regulatory-roles-under-osmotic-stress-in-escherichia-coli-k-12-mg1655
#9
Sang Woo Seo, Ye Gao, Donghyuk Kim, Richard Szubin, Jina Yang, Byung-Kwan Cho, Bernhard O Palsson
A transcription factor (TF), OmpR, plays a critical role in transcriptional regulation of the osmotic stress response in bacteria. Here, we reveal a genome-scale OmpR regulon in Escherichia coli K-12 MG1655. Integrative data analysis reveals that a total of 37 genes in 24 transcription units (TUs) belong to OmpR regulon. Among them, 26 genes show more than two-fold changes in expression level in an OmpR knock-out strain. Specifically, we find that: 1) OmpR regulates mostly membrane-located gene products involved in diverse fundamental biological processes, such as narU (encoding nitrate/nitrite transporter), ompX (encoding outer membrane protein X), and nuoN (encoding NADH:ubiquinone oxidoreductase); 2) by investigating co-regulation of entire sets of genes regulated by other stress-response TFs, stresses are surprisingly independently regulated among each other; and, 3) a detailed investigation of the physiological roles of the newly discovered OmpR regulon genes reveals that activation of narU represents a novel strategy to significantly improve osmotic stress tolerance of E...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28515717/the-leaderless-bacteriocin-enterocin-k1-is-highly-potent-against-enterococcus-faecium-a-study-on-structure-target-spectrum-and-receptor
#10
Kirill V Ovchinnikov, Per Eugen Kristiansen, Daniel Straume, Marianne S Jensen, Tamara Aleksandrzak-Piekarczyk, Ingolf F Nes, Dzung B Diep
Enterocin K1 (EntK1), enterocin EJ97 (EntEJ97), and LsbB are three sequence related leaderless bacteriocins. Yet LsbB kills only lactococci while EntK1 and EntEJ97 target wider spectra with EntK1 being particularly active against Enterococcus faecium, including nosocomial multidrug resistant isolates. NMR study of EntK1 showed that it had a structure very similar to LsbB - both having an amphiphilic N-terminal α-helix and an unstructured C-terminus. The α-helix in EntK1 is, however, about 3-4 residues longer than that of LsbB...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28513097/evidence-for-a-peptidoglycan-like-structure-in-orientia-tsutsugamushi
#11
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/28512454/new-insights-into-the-regulation-of-cell-surface-signaling-activity-acquired-from-a-mutagenesis-screen-of-the-pseudomonas-putida-iuty-sigma-anti-sigma-factor
#12
Karlijn C Bastiaansen, Cristina Civantos, Wilbert Bitter, María A Llamas
Cell-surface signaling (CSS) is a signal transfer system that allows Gram-negative bacteria to detect environmental signals and generate a cytosolic response. These systems are composed of an outer membrane receptor that senses the inducing signal, an extracytoplasmic function sigma factor (σ(ECF)) that targets the cytosolic response by modifying gene expression and a cytoplasmic membrane anti-sigma factor that keeps the σ(ECF) in an inactive state in the absence of the signal and transduces its presence from the outer membrane to the cytosol...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28512090/the-vibrio-cholerae-vexgh-rnd-efflux-system-maintains-cellular-homeostasis-by-effluxing-vibriobactin
#13
Dillon E Kunkle, X Renee Bina, James E Bina
Resistance-nodulation-division (RND) superfamily efflux systems have been widely studied for their role in antibiotic resistance, but their native biological functions remain poorly understood. We previously showed that loss of RND-mediated efflux in Vibrio cholerae resulted in activation of the Cpx two-component regulatory system, which mediates adaptation to stress resulting from misfolded membrane proteins. Here, we investigated the mechanism linking RND-mediated efflux to the Cpx response. We performed transposon mutagenesis screening of RND-deficient V...
May 16, 2017: MBio
https://www.readbyqxmd.com/read/28505496/inactivation-of-gram-bacteria-salmonella-enterica-by-chlorophyllin-based-photosensitization-mechanism-of-action-and-new-strategies-to-enhance-the-inactivation-efficiency
#14
Irina Buchovec, Viktorija Lukseviciūtė, Rita Kokstaite, Danute Labeikyte, Laura Kaziukonyte, Zivile Luksiene
This study is focused on the enhancement of susceptibility of Gram (-) bacteria S. enterica to chlorophyllin-based (Chl) photosensitization combining it with other antimicrobial tools. In order to find best combinations, the mechanism by which Chl-based photosensitization inactivates bacteria must be identified. Data confirmed that photosensitization (Chl 1.5×10(-5)M, for 1-120min, 405nm, 0-46.1J/cm(2)) reduced S. enterica population, just by 2.05 log (CFU/ml). Fluorimetric measurements indicated that just minor part of Chl was bound to Salmonella in suspension...
May 9, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28495615/a-novel-function-of-tlr4-in-mediating-the-immunomodulatory-effect-of-benzanthrone-an-environmental-pollutant
#15
Prachi Tewari, Payal Mandal, Ruchi Roy, Somya Asthana, Premendra D Dwivedi, Mukul Das, Anurag Tripathi
Our prior studies have reported that Benzanthrone (BA) manifests inflammatory responses in the spleen of Balb/c mice. The present investigation was carried out to study the impact of BA on macrophages, which are the primary scavenger cells in the body that act as a connecting link between innate and adaptive immunity. Parenteral administration of BA (daily for one week) to mice resulted in enhanced levels of nitric oxide (NO) and overexpression of inflammatory markers (COX-2, MMP-9 and PGE-2) in macrophages; however the level of MHC class-I and MHC class-II receptors were down regulated...
July 5, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28484043/the-long-hunt-for-pssr-looking-for-a-phospholipid-synthesis-transcriptional-regulator-finding-the-ribosome
#16
J Bartoli, L My, Lucid Belmudes, Yohann Couté, J P Viala, E Bouveret
The phospholipid (PL) composition of bacterial membranes varies as a function of growth rate and in response to changes in the environment. While growth adaptation can be explained by biochemical feedbacks in the PL synthesis pathway, recent transcriptome studies have revealed that the expression of PL synthesis genes can also be tuned in response to various stresses. We previously showed that the BasRS two-component pathway controls expression of the diacylglycerol kinase gene dgkA in Escherichia coli (Wahl et al, Mol...
May 8, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28467057/conditional-chaperone-client-interactions-revealed-by-genetically-encoded-photo-cross-linkers
#17
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/28450373/rnaseq-analysis-of-the-drosophila-response-to-the-entomopathogenic-nematode-steinernema
#18
Shruti Yadav, Sean Daugherty, Amol Carl Shetty, Ioannis Eleftherianos
Drosophila melanogaster is an outstanding model to study the molecular and functional basis of host-pathogen interactions. Currently our knowledge of microbial infections in D. melanogaster is well understood, however the response of flies to nematode infections is still in its infancy. Here we have used the potent parasitic nematode Steinernema carpocapsae that lives in mutualism with its endosymbiotic bacteria X. nematophila to examine the transcriptomic basis of the interaction between D. melanogaster and entomopathogenic nematodes...
April 26, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28444395/effects-of-n-acetyl-l-cysteine-on-the-membrane-vesicle-release-and-growth-of-respiratory-pathogens
#19
Charlotte Volgers, Birke J Benedikter, Gert E Grauls, Pauline H M Hellebrand, Paul H M Savelkoul, Frank R M Stassen
Bacterial infections contribute to the disease progression of chronic obstructive pulmonary disease by stimulating mucus production in the airways. This increased mucus production and other symptoms are often alleviated when patients are treated with mucolytics such as N-acetyl-L-cysteine (NAC). Moreover, NAC has been suggested to inhibit bacterial growth. Bacteria can release membrane vesicles (MVs) in response to stress, and recent studies report a role for these proinflammatory MVs in the pathogenesis of airways disease...
May 1, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28443079/pleomorphism-and-viability-of-the-lyme-disease-pathogen-borrelia-burgdorferi-exposed-to-physiological-stress-conditions-a-correlative-cryo-fluorescence-and-cryo-scanning-electron-microscopy-study
#20
Marie Vancová, Nataliia Rudenko, Jiří Vaněček, Maryna Golovchenko, Martin Strnad, Ryan O M Rego, Lucie Tichá, Libor Grubhoffer, Jana Nebesářová
To understand the response of the Lyme disease spirochete Borrelia burgdorferi exposed to stress conditions and assess the viability of this spirochete, we used a correlative cryo-fluorescence and cryo-scanning microscopy approach. This approach enables simple exposition of bacteria to various experimental conditions that can be stopped at certain time intervals by cryo-immobilization, examination of cell viability without necessity to maintain suitable culture conditions during viability assays, and visualization of structures in their native state at high magnification...
2017: Frontiers in Microbiology
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