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stress response envelope

Xavier Carette, John Platig, David C Young, Michaela Helmel, Albert T Young, Zhe Wang, Lakshmi-Prasad Potluri, Cameron Stuver Moody, Jumei Zeng, Sladjana Prisic, Joseph N Paulson, Jan Muntel, Ashoka V R Madduri, Jorge Velarde, Jacob A Mayfield, Christopher Locher, Tiansheng Wang, John Quackenbush, Kyu Y Rhee, D Branch Moody, Hanno Steen, Robert N Husson
Tuberculosis is the leading killer among infectious diseases worldwide. Increasing multidrug resistance has prompted new approaches for tuberculosis drug development, including targeted inhibition of virulence determinants and of signaling cascades that control many downstream pathways. We used a multisystem approach to determine the effects of a potent small-molecule inhibitor of the essential Mycobacterium tuberculosis Ser/Thr protein kinases PknA and PknB. We observed differential levels of phosphorylation of many proteins and extensive changes in levels of gene expression, protein abundance, cell wall lipids, and intracellular metabolites...
March 6, 2018: MBio
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...
February 27, 2018: Antonie Van Leeuwenhoek
Kevin M Claunch, Madeline Bush, Christopher R Evans, Jacob A Malmquist, Matthew C Hale, Shauna M McGillivray
ClpX functions as either an independent chaperone or a component of the ClpXP protease, a conserved intracellular protease that acts as a global regulator in the bacterial cell by degrading regulatory proteins, stress response proteins and rate-limiting enzymes. Previously, we found that loss of clpX in Bacillus anthracis Sterne leads to increased susceptibility to antimicrobial agents that target the cell envelope. The aim of this study was to identify genes within the regulatory network of clpX that contribute to antimicrobial resistance...
February 23, 2018: Microbiology
Joana Rocha, Milène Nitenberg, Agnès Girard-Egrot, Juliette Jouhet, Eric Maréchal, Maryse A Block, Christelle Breton
A unique feature of chloroplasts is their high content of the galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), which constitute up to 80% of their lipids. These galactolipids are synthesized in the chloroplast envelope membrane through the concerted action of galactosyltransferases, the so-called 'MGDG synthases (MGDs)' and 'DGDG synthases (DGDs),' which use uridine diphosphate (UDP)-galactose as donor. In Arabidopsis leaves, under standard conditions, the enzymes MGD1 and DGD1 provide the bulk of galactolipids, necessary for the massive expansion of thylakoid membranes...
2018: Frontiers in Plant Science
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
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
Anna Yurievna Arinbasarova, Andrey Valerievich Machulin, Elena Nikolaevna Biryukova, Vladimir Vladislavovich Sorokin, Alexander Grigorievich Medentsev, Nataliya Egorovna Suzina
The ultrastructural changes in the cell envelope of the yeast Yarrowia lipolytica as stress response were examined using electron microscopy technique. The formation of new cellular surface structures including membrane vesicles, pore channels and wall surface globules were shown for the first time under conditions of oxidative (endogenous and exogenous) or thermal stress. This demonstrates once again that under stress conditions the microorganisms reveal properties unknown for them before. Particularly noteworthy is the silicon accumulation, which was revealed at the surface globules with X-ray microanalysis of the elemental composition of cells' thin sections...
February 14, 2018: Canadian Journal of Microbiology
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
Brittany D Bennett, Kaitlyn E Redford, Jeffrey A Gralnick
Shewanella oneidensis strain MR-1 is a versatile bacterium capable of respiring extracellular, insoluble ferric oxide minerals under anaerobic conditions. The respiration of iron minerals results in the production of soluble ferrous ions, which at high concentrations are toxic to living organisms. It is not fully understood how Fe2+ is toxic to cells anaerobically; nor is it fully understood how S. oneidensis is able to resist high levels of Fe2+ Here we describe the results of a transposon-mutant screen and subsequent deletion of the genes clpX and clpP in S...
January 29, 2018: Journal of Bacteriology
Jennifer M Hayashi, Kirill Richardson, Emily S Melzer, Steven J Sandler, Bree B Aldridge, M Sloan Siegrist, Yasu S Morita
Cell elongation occurs primarily at the mycobacterial cell poles, but the molecular mechanisms governing this spatial regulation remain elusive. We recently reported the presence of an intracellular membrane domain (IMD) that was spatially segregated from the conventional plasma membrane in Mycobacterium smegmatis The IMD is enriched in the polar region of actively elongating cells and houses many essential enzymes involved in envelope biosynthesis, suggesting its role in spatially restricted elongation at the cell poles...
January 23, 2018: MBio
Masayuki Shintaku, Daita Kaneda, Kiyomitsu Oyanagi
The patient was an 81-year-old woman diagnosed with atypical motor neuron disease who died after a long clinical course (7.5 years without mechanical assistance of ventilation) characterized by lower motor neuron signs and symptoms. Upper motor neuron signs and cognitive impairment were not apparent. Autopsy demonstrated severe neuronal loss in the anterior horn of the spinal cord, and some of the remaining neurons showed enlargement of Nissl substance and apparent thickening of the nuclear envelopes. No Bunina bodies, skein-like inclusions, or structures immunoreactive for phosphorylated transactivation response DNA-binding protein 43 were found...
January 19, 2018: Clinical Neuropathology
Kei Asai
Proteins belonging to the sigma factor family in eubacteria initiate transcription by associating with RNA polymerase. A subfamily, the extracytoplasmic function (ECF) sigma factors, which form a widely distributed bacterial signal transduction system comprising a sigma factor and a cognate membrane-embedded anti-sigma factor, regulates genes in response to stressors that threaten cell envelope integrity including the cell wall and membrane. The Gram-positive soil bacterium Bacillus subtilis provides a valuable model for investigation of the ECF sigma factors...
January 17, 2018: Genes & Genetic Systems
Lana Dbeibo, Julia J van Rensburg, Sara N Smith, Kate R Fortney, Dharanesh Gangaiah, Hongyu Gao, Juan Marzoa, Yunlong Liu, Harry L T Mobley, Stanley M Spinola
CpxRA is an envelope stress response system found in all species of Enterobacteriaceae; CpxA has kinase activity for CpxR and phosphatase activity for phospho-CpxR, a transcription factor. CpxR also accepts phosphate groups and acetyl phosphate, a glucose metabolite. Activation of CpxR increases transcription of genes encoding for membrane repair and downregulates virulence determinants. We hypothesized that activation of CpxR could serve as an antimicrobial/antivirulence strategy and discovered compounds that activate CpxR in Escherichia coli by inhibiting CpxA phosphatase activity...
January 8, 2018: Infection and Immunity
Rafal Sawicki, Elwira Sieniawska, Marta Swatko-Ossor, Joanna Golus, Grazyna Ginalska
In the past few years, there has been a significant increase in detection of drug resistant strains of Mycobacterium tuberculosis. Search for new antimycobacterial drugs brought natural sources with their chemical diversity in focus. Especially essential oils, produced by plants also for toxic effect, are reservoir of potentially antitubercular compounds. In the present work, we exposed M. tuberculosis H37Ra ATCC 25177 strain to some terpenes commonly occurring in essential oils. Gene expression profiling was used to explore possible influence of these compounds on stress sensing and envelope preserving function...
December 27, 2017: Food and Chemical Toxicology
Sandro Baldi, Alessio Bolognesi, Anne Cornelis Meinema, Yves Barral
Although individuals of many species inexorably age, a number of observations established that the rate of ageing is modulated in response to a variety of mild stresses. Here, we investigated how heat stress promotes longevity in yeast. We show that upon growth at higher temperature, yeast cells relax the retention of DNA circles, which act as ageing factors in the mother cell. The enhanced frequency at which circles redistribute to daughter cells was not due to changes of anaphase duration or nuclear shape but solely to the downregulation of the diffusion barrier in the nuclear envelope...
December 28, 2017: ELife
Maikel Boot, Vincent J C van Winden, Marion Sparrius, Robert van de Weerd, Alexander Speer, Roy Ummels, Tige Rustad, David R Sherman, Wilbert Bitter
The cell envelope of mycobacteria is a highly unique and complex structure that is functionally equivalent to that of Gram-negative bacteria to protect the bacterial cell. Defects in the integrity or assembly of this cell envelop must be sensed to allow the induction of stress response systems. The promoter that is specifically and most strongly induced upon exposure to ethambutol and isoniazid, first line drugs that affect cell envelope biogenesis, is the iniBAC promoter. In this study, we set out to identify the regulator of the iniBAC operon in Mycobacterium marinum using an unbiased transposon mutagenesis screen in a constitutively iniBAC-expressing mutant background...
December 27, 2017: PLoS Genetics
Jean-David Rochaix, Silvia Ramundo
Although chloroplasts contain their own genetic system and are semi-autonomous cell organelles, plastid biogenesis and homeostasis are heavily dependent on the nucleo-cytosolic compartment. These two cellular compartments are closely co-ordinated through a complex signaling network comprising both anterograde and retrograde signaling chains. Developmental changes or any perturbation in the chloroplast system induced by a particular stress resulting from changes in environmental conditions such as excess light, elevated temperature, nutrient limitation, pathogen infection, give rise to specific signals...
December 21, 2017: Essays in Biochemistry
Jara Radeck, Nina Lautenschläger, Thorsten Mascher
The bacterial cell wall separates the cell from its surrounding and protects it from environmental stressors. Its integrity is maintained by a highly regulated process of cell wall biosynthesis. The membrane-located lipid II cycle provides cell wall building blocks that are assembled inside the cytoplasm to the outside for incorporation. Its carrier molecule, undecaprenyl phosphate (UP), is then recycled by dephosphorylation from undecaprenyl pyrophosphate (UPP). In Bacillus subtilis, this indispensable reaction is catalyzed by the UPP phosphatases BcrC and UppP...
2017: Frontiers in Microbiology
Feng Zhang, Li Tian, Xiaoping Shang, Xiang Li, Rui Xue, Shuhua Cheng, Changying Chen
AIM: To examine first-line nurse managers' perceptions of safety culture and explore relationships between their safety attitudes and safety factors in Henan Province, China. BACKGROUND: Health providers' perceptions of patient safety culture have been studied widely, but little is known about first-line nurse managers' safety attitudes. METHODS: A cross-sectional survey was conducted with a convenience sample of 823 first-line nurse managers in 216 hospitals across Henan Province, China...
December 7, 2017: Journal of Nursing Management
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
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