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stress response membrane bacteria

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https://www.readbyqxmd.com/read/29472899/exposure-to-sub-lethal-2-4-dichlorophenoxyacetic-acid-arrests-cell-division-and-alters-cell-surface-properties-in-escherichia-coli
#1
Supriya V Bhat, Belma Kamencic, André Körnig, Zinnat Shahina, Tanya E S Dahms
Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro , and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force - laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29458656/stress-responses-outer-membrane-permeability-control-and-antimicrobial-resistance-in-enterobacteriaceae
#2
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)...
January 25, 2018: Microbiology
https://www.readbyqxmd.com/read/29455524/multiwall-carbon-nanotubes-induce-more-pronounced-transcriptomic-responses-in-pseudomonas-aeruginosa-pg201-than-graphene-exfoliated-boron-nitride-or-carbon-black
#3
Monika Mortimer, Naresh Devarajan, Dong Li, Patricia A Holden
Carbonaceous and boron nitride (BN) nanomaterials have similar applications and hydrophobic properties suggesting common release pathways and exposure to bacteria. While high nanomaterial concentrations can be bactericidal or growth-inhibitory, little is known regarding bacterial transcriptional responses to non-growth-inhibitory nanomaterial concentrations. Here, using one strain of Pseudomonas aeruginosa-a clinically and environmentally important bacterial taxon-we analyzed the comparative transcriptomic response to carbonaceous or BN nanomaterials...
February 19, 2018: ACS Nano
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
#4
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...
February 15, 2018: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29414707/analyzing-thermal-stability-of-cell-membrane-of%C3%A2-salmonella-using-time-multiplexed-impedance-sensing
#5
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/29393629/synergistic-bacterial-stress-results-from-exposure-to-nano-ag-and-nano-tio2-mixtures-under-light-in-environmental-media
#6
Carolyn M Wilke, Bettina Wunderlich, Jean-François Gaillard, Kimberly A Gray
Due to their widespread use and subsequent release, engineered nanomaterials (ENMs) will create complex mixtures and emergent systems in the natural environment where their chemical interactions may cause toxic stress to microorganisms. We previously showed that under dark conditions n-TiO2 attenuated bacterial stress caused by low concentrations of n-Ag (<20 μg L-1) due to Ag+ adsorption. Yet, since both n-Ag and n-TiO2 are photoactive, their photochemistries may play a key role in their interactions. In this work, we study the chemical interactions of n-Ag and n-TiO2 mixtures in a natural aqueous medium under simulated solar irradiation to investigate the effects of photoinduced stress...
February 2, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29382730/translation-stress-positively-regulates-mscl-dependent-excretion-of-cytoplasmic-proteins
#7
Rosa Morra, Francesco Del Carratore, Howbeer Muhamadali, Luminita Gabriela Horga, Samantha Halliwell, Royston Goodacre, Rainer Breitling, Neil Dixon
The apparent mislocalization or excretion of cytoplasmic proteins is a commonly observed phenomenon in both bacteria and eukaryotes. However, reports on the mechanistic basis and the cellular function of this so-called "nonclassical protein secretion" are limited. Here we report that protein overexpression in recombinant cells and antibiotic-induced translation stress in wild-type Escherichia coli cells both lead to excretion of cytoplasmic protein (ECP). Condition-specific metabolomic and proteomic analyses, combined with genetic knockouts, indicate a role for both the large mechanosensitive channel (MscL) and the alternative ribosome rescue factor A (ArfA) in ECP...
January 30, 2018: MBio
https://www.readbyqxmd.com/read/29356594/proteomic-analysis-of-alterations-in-aeromonas-hydrophila-outer-membrane-proteins-in-response-to-oxytetracycline-stress
#8
Ling Lin, Lina Sun, Farman Ali, Zhuang Guo, Liang Zhang, Wenxiong Lin, Xiangmin Lin
In Gram-negative bacteria, the outer membrane proteins (OMPs) perform a crucial role in antibiotic resistance, but it is largely unknown how they behave in response to antibiotic stress. In this study, we treated Aeromonas hydrophila with two different doses of oxytetracycline (OXY) to induce antibiotic stress. Proteins were isolated from sarcosine-insoluble fractions and quantitatively examined by using tandem mass tag labeling-based mass spectrometry to identify differentially expressed proteins. As a result, we identified 125 differential proteins in the 5 μg/ml OXY treatment group, including 20 OMPs, and 150 proteins from the 10 μg/ml OXY group, including 22 OMPs...
January 22, 2018: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/29352745/negative-supercoiling-of-dna-by-gyrase-is-inhibited-in-salmonella-enterica-serovar-typhimurium-during-adaptation-to-acid-stress
#9
Aoife M Colgan, Heather J Quinn, Stefani C Kary, Lesley A Mitchenall, Anthony Maxwell, Andrew Ds Cameron, Charles J Dorman
DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4 to 5) macrophage vacuole and DNA relaxation correlates with upregulation of Salmonella genes involved in adaptation to the macrophage environment. Bacterial ATP levels did not increase during adaptation to acid pH unless the bacterium was deficient in MgtC, a cytoplasmic-membrane-located inhibitor of proton-driven F1 F0 ATP synthase activity. Inhibiting ATP binding by DNA gyrase and topo IV with novobiocin enhanced the effect of low pH on DNA relaxation...
January 20, 2018: Molecular Microbiology
https://www.readbyqxmd.com/read/29339384/a-novel-inhibitor-of-the-lolcde-abc-transporter-essential-for-lipoprotein-trafficking-in-gram-negative-bacteria
#10
Nicholas N Nickerson, Christine C Jao, Yiming Xu, John Quinn, Elizabeth Skippington, Mary Kate Alexander, Anh Miu, Nicholas Skelton, Jessica V Hankins, Michael S Lopez, Christopher M Koth, Steven Rutherford, Mireille Nishiyama
The outer membrane is an essential structural component of Gram-negative bacteria that is composed of lipoproteins, lipopolysaccharides, phospholipids, and integral β-barrel membrane proteins. A dedicated machinery, called the Lol system, ensures proper trafficking of lipoproteins from the inner to the outer membrane. The LolCDE ABC transporter is the inner membrane component, which is essential for bacterial viability. Here, we report a novel pyrrolopyrimidinedione compound, G0507, which was identified in a phenotypic screen for inhibitors of E...
January 16, 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29330179/influence-of-type-i-fimbriae-and-fluid-shear-stress-on-bacterial-behavior-and-multicellular-architecture-of-early-escherichia-coli-biofilms-at-single-cell-resolution
#11
Liyun Wang, Robert Keatch, Qi Zhao, John A Wright, Clare E Bryant, Anna L Redmann, Eugene M Terentjev
Biofilm formation on abiotic surfaces in food and medical industry can cause severe contamination and infection, yet how biological and physical factors determine cellular architecture of early biofilms and bacterial behavior of the constituent cells remains largely unknown. In this study we examine the specific role of type-I fimbriae in nascent stages of biofilm formation and the response of micro-colonies to environmental flow shear at single-cell resolution. The results show that type-I fimbriae are not required for reversible adhesion from plankton, but critical for irreversible adhesion of Escherichia coli (E...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29233892/stable-signal-peptides-and-the-response-to-secretion-stress-in-staphylococcus-aureus
#12
Arryn Craney, Floyd E Romesberg
Protein secretion is essential, but how it is managed is poorly understood. In bacteria, most secreted proteins require release from the outer surface of the cytoplasmic membrane by type I signal peptidase (SPase), which cleaves the mature protein from its membrane-bound N-terminal signal peptide. As the first step that occurs outside the protected cytoplasmic environment and because insufficient activity can rapidly result in the toxic accumulation of preproteins, the activity of SPase is expected to be closely monitored and perhaps supplemented when insufficient...
December 12, 2017: MBio
https://www.readbyqxmd.com/read/29212037/a-bacterial-receptor-pcrk-senses-the-plant-hormone-cytokinin-to-promote-adaptation-to-oxidative-stress
#13
Fang-Fang Wang, Shou-Ting Cheng, Yao Wu, Bao-Zhen Ren, Wei Qian
Recognition of the host plant is a prerequisite for infection by pathogenic bacteria. However, how bacterial cells sense plant-derived stimuli, especially chemicals that function in regulating plant development, remains completely unknown. Here, we have identified a membrane-bound histidine kinase of the phytopathogenic bacterium Xanthomonas campestris, PcrK, as a bacterial receptor that specifically detects the plant cytokinin 2-isopentenyladenine (2iP). 2iP binds to the extracytoplasmic region of PcrK to decrease its autokinase activity...
December 5, 2017: Cell Reports
https://www.readbyqxmd.com/read/29211886/bicarbonate-induces-high-level-resistance-to-the-human-antimicrobial-peptide-ll-37-in-staphylococcus-aureus-small-colony-variants
#14
Ping Zhang, John A Wright, Anna Tymon, Sean P Nair
Objectives: Staphylococcus aureus small colony variants (SCVs) cause persistent infections and are resistant to cationic antibiotics. Antimicrobial peptides (AMPs) have been suggested as promising alternatives for treating antibiotic-resistant bacteria. We investigated the capacity of the human cationic AMP LL-37 to kill SCVs in the presence of physiological concentrations of bicarbonate, which are reported to alter bacterial membrane permeability and change resistance of bacteria to AMPs...
December 4, 2017: Journal of Antimicrobial Chemotherapy
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
#15
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/29209964/probing-the-toxicity-mechanism-of-multiwalled-carbon-nanotubes-on-bacteria
#16
Maria R Hartono, Ariel Kushmaro, Xiaodong Chen, Robert S Marks
Carbon nanotubes (CNTs) have emerged recently as superior adsorbent materials for the removal of recalcitrant pollutants. The potential of combining the sorption capability of CNTs with bacterial degradation for pollutant removal, however, necessitates further investigation of the mechanisms of CNTs' toxicity towards bacterial cells. In this study, we used a panel of stress-responsive recombinant Escherichia coli bioluminescence bacterial strains to explore the possible mechanisms of toxicity of multiwalled carbon nanotubes (MWCNTs)...
December 5, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29209784/acaxl2-and-acmst1-regulate-arthrospore-development-and-stress-resistance-in-the-cephalosporin-c-producer-acremonium-chrysogenum
#17
Janina Kluge, Ulrich Kück
The filamentous fungus Acremonium chrysogenum is the primordial producer of the β-lactam antibiotic cephalosporin C. This antibiotic is of major biotechnological and medical relevance because of its antibacterial activity against Gram-positive and Gram-negative bacteria. Antibiotic production during the lag phase of fermentation is often accompanied by a typical morphological feature of A. chrysogenum, the fragmentation of the mycelium into arthrospores. Here, we sought to identify factors that regulate the hyphal septation process and present the first comparative functional characterization of the type I integral plasma membrane protein Axl2 (axial budding pattern protein 2), a central component of the bud site selection system (BSSS) and Mst1 (mammalian Sterile20-like kinase), a septation initiation network (SIN)-associated germinal center kinase (GCK)...
December 5, 2017: Current Genetics
https://www.readbyqxmd.com/read/29208747/proposed-role-for-kaic-like-atpases-as-major-signal-transduction-hubs-in-archaea
#18
Kira S Makarova, Michael Y Galperin, Eugene V Koonin
All organisms must adapt to ever-changing environmental conditions and accordingly have evolved diverse signal transduction systems. In bacteria, the most abundant networks are built around the two-component signal transduction systems that include histidine kinases and receiver domains. In contrast, eukaryotic signal transduction is dominated by serine/threonine/tyrosine protein kinases. Both of these systems are also found in archaea, but they are not as common and diversified as their bacterial and eukaryotic counterparts, suggesting the possibility that archaea have evolved other, still uncharacterized signal transduction networks...
December 5, 2017: MBio
https://www.readbyqxmd.com/read/29183977/osmosensing-by-the-bacterial-phoq-phop-two-component-system
#19
Jing Yuan, Fan Jin, Timo Glatter, Victor Sourjik
The PhoQ/PhoP two-component system plays an essential role in the response of enterobacteria to the environment of their mammalian hosts. It is known to sense several stimuli that are potentially associated with the host, including extracellular magnesium limitation, low pH, and the presence of cationic antimicrobial peptides. Here, we show that the PhoQ/PhoP two-component systems of Escherichia coli and Salmonella can also perceive an osmotic upshift, another key stimulus to which bacteria become exposed within the host...
November 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29163430/pdtas-deficiency-affects-resistance-of-mycobacteria-to-ribosome-targeting-antibiotics
#20
Karolina Dadura, Renata Płocińska, Anna Rumijowska-Galewicz, Przemysław Płociński, Anna Żaczek, Bożena Dziadek, Andrzej Zaborowski, Jarosław Dziadek
Two-component regulatory systems (TCSSs) are key regulatory elements responsible for the adaptation of bacteria to environmental stresses. A classical TCSS is typically comprised of a sensory histidine kinase and a corresponding response regulator. Here, we used homologous recombination to construct a Mycobacterium smegmatis mutant defective in the synthesis of cytosolic histidine kinase PdtaS (Msmeg_1918). The resulting ΔpdtaS mutant strain was tested in the Phenotype Microarray screening system, which allowed us to identify aminoglycoside antibiotic sensitivity, tetracyclines antibiotic resistance as well as membrane transport and respiration, as the main processes affected by removal of pdtaS...
2017: Frontiers in Microbiology
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