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https://www.readbyqxmd.com/read/28513097/evidence-for-a-peptidoglycan-like-structure-in-orientia-tsutsugamushi
#1
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/28490498/shelterin-components-mediate-genome-reorganization-in-response-to-replication-stress
#2
Takeshi Mizuguchi, Nitika Taneja, Emiko Matsuda, Jon-Matthew Belton, Peter FitzGerald, Job Dekker, Shiv I S Grewal
The dynamic nature of genome organization impacts critical nuclear functions including the regulation of gene expression, replication, and DNA damage repair. Despite significant progress, the mechanisms responsible for reorganization of the genome in response to cellular stress, such as aberrant DNA replication, are poorly understood. Here, we show that fission yeast cells carrying a mutation in the DNA-binding protein Sap1 show defects in DNA replication progression and genome stability and display extensive changes in genome organization...
May 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28467057/conditional-chaperone-client-interactions-revealed-by-genetically-encoded-photo-cross-linkers
#3
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/28447386/unravelling-the-pleiotropic-role-of-the-mceg-atpase-in-mycobacterium-smegmatis
#4
Julia García-Fernández, Kadamba Papavinasasundaram, Beatriz Galán, Christopher M Sassetti, José L García
The Mce systems are complex ABC transporters that are encoded by different numbers of homologous operons in Actinobacteria. While the four Mce systems of Mycobacterium tuberculosis are all energized by a single ATPase, MceG, each system appears to import different fatty acids or sterols. To explore if this behaviour can be extended to saprophytic mycobacteria, whose more complex genomes encode more Mce systems, we have identified and characterized the MceG orthologue of Mycobacterium smegmatis. This bacterium relies on MceG to energize its six Mce systems that contribute to a variety of cellular functions including sterol uptake and cell envelope maintenance...
April 26, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28439041/cues-from-the-membrane-bacterial-glycerophospholipids
#5
Zachary D Dalebroux
In this issue of Journal of Bacteriology, Rowlett et al. unveil new Escherichia coli circuitry linking membrane glycerophospholipid (GPL) homeostasis to bacterial stress response and adaptation mechanisms. Glycerophospholipids comprise critical components of the dual-membrane envelope of Gram-negative bacteria and participate in many processes. The new evidence suggests that in some instances distinct E. coli GPL molecules function for distinct biochemistry, and bacteria sense perturbations in membrane GPL concentrations to coordinate survival strategies...
April 24, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28439040/the-impact-of-membrane-phospholipid-alterations-in-escherichia-coli-on-cellular-function-and-bacterial-stress-adaptation
#6
Veronica W Rowlett, Venkata K P S Mallampalli, Anja Karlstaedt, William Dowhan, Heinrich Taegtmeyer, William Margolin, Heidi Vitrac
Bacteria have evolved multiple strategies to sense and rapidly adapt to challenging and ever-changing environmental conditions. The ability to alter membrane lipid composition, a key component of the cellular envelope, is crucial for bacterial survival and adaptation in response to environmental stress. However, the precise roles played by membrane phospholipids in bacterial physiology and stress adaptation are not fully elucidated. The goal of this study was to define the role of membrane phospholipids in adaptation to stress and maintenance of bacterial cell fitness...
April 24, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28428255/nucleosome-nucleosome-interactions-via-histone-tails-and-linker-dna-regulate-nuclear-rigidity
#7
Yuta Shimamoto, Sachiko Tamura, Hiroshi Masumoto, Kazuhiro Maeshima
Cells, as well as the nuclei inside them, experience significant mechanical stress in diverse biological processes including contraction, migration, and adhesion. The structural stability of nuclei must therefore be maintained in order to protect genome integrity. Despite extensive knowledge on nuclear architecture and components, however, the underlying physical and molecular mechanisms remain largely unknown. We addressed this in the present study by subjecting isolated human cell nuclei to microneedle-based quantitative micromanipulation with a series of biochemical perturbations of the chromatin...
April 20, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28416660/redefining-the-essential-trafficking-pathway-for-outer-membrane-lipoproteins
#8
Marcin Grabowicz, Thomas J Silhavy
The outer membrane (OM) of Gram-negative bacteria is a permeability barrier and an intrinsic antibiotic resistance factor. Lipoproteins are OM components that function in cell wall synthesis, diverse secretion systems, and antibiotic efflux pumps. Moreover, each of the essential OM machines that assemble the barrier requires one or more lipoproteins. This dependence is thought to explain the essentiality of the periplasmic chaperone LolA and its OM receptor LolB that traffic lipoproteins to the OM. However, we show that in strains lacking substrates that are toxic when mislocalized, both LolA and LolB can be completely bypassed by activating an envelope stress response without compromising trafficking of essential lipoproteins...
May 2, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28408482/small-regulatory-bacterial-rnas-regulating-the-envelope-stress-response
#9
REVIEW
Gracjana Klein, Satish Raina
Most bacteria encode a large repertoire of RNA-based regulatory mechanisms. Recent discoveries have revealed that the expression of many genes is controlled by a plethora of base-pairing noncoding small regulatory RNAs (sRNAs), regulatory RNA-binding proteins and RNA-degrading enzymes. Some of these RNA-based regulated processes respond to stress conditions and are involved in the maintenance of cellular homeostasis. They achieve it by either direct posttranscriptional repression of several mRNAs, including blocking access to ribosome and/or directing them to RNA degradation when the synthesis of their cognate proteins is unwanted, or by enhanced translation of some key stress-regulated transcriptional factors...
April 15, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/28402889/unbiased-high-precision-cell-mechanical-measurements-with-microconstrictions
#10
Janina R Lange, Claus Metzner, Sebastian Richter, Werner Schneider, Monika Spermann, Thorsten Kolb, Graeme Whyte, Ben Fabry
We describe a quantitative, high-precision, high-throughput method for measuring the mechanical properties of cells in suspension with a microfluidic device, and for relating cell mechanical responses to protein expression levels. Using a high-speed (750 fps) charge-coupled device camera, we measure the driving pressure Δp, maximum cell deformation εmax, and entry time tentry of cells in an array of microconstrictions. From these measurements, we estimate population averages of elastic modulus E and fluidity β (the power-law exponent of the cell deformation in response to a step change in pressure)...
April 11, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28401134/preconsult-interactive-computer-assisted-client-assessment-survey-for-common-mental-disorders-in-a-community-health-centre-a-randomized-controlled-trial
#11
Farah Ahmad, Wendy Lou, Yogendra Shakya, Liane Ginsburg, Peggy T Ng, Meb Rashid, Serban Dinca-Panaitescu, Cliff Ledwos, Kwame McKenzie
BACKGROUND: Access disparities for mental health care exist for vulnerable ethnocultural and immigrant groups. Community health centres that serve these groups could be supported further by interactive, computer-based, self-assessments. METHODS: An interactive computer-assisted client assessment survey (iCCAS) tool was developed for preconsult assessment of common mental disorders (using the Patient Health Questionnaire [PHQ-9], Generalized Anxiety Disorder 7-item [GAD-7] scale, Primary Care Post-traumatic Stress Disorder [PTSD-PC] screen and CAGE [concern/cut-down, anger, guilt and eye-opener] questionnaire), with point-of-care reports...
January 2017: CMAJ Open
https://www.readbyqxmd.com/read/28373273/appropriate-regulation-of-the-%C3%AF-e-dependent-envelope-stress-response-is-necessary-to-maintain-cell-envelope-integrity-and-stationary-phase-survival-in-escherichia-coli
#12
Hervé Nicoloff, Saumya Gopalkrishnan, Sarah E Ades
The alternative sigma factor σ(E) is a key component of the Escherichia coli response to cell envelope stress and is required for viability even in the absence of stress. σ(E) activity increases during entry into stationary phase suggesting an important role for σ(E) when nutrients are limiting. Elevated σ(E) activity has been proposed to activate a pathway leading to lysis of non-culturable cells that accumulate during early stationary phase. To better understand σ(E)-directed cell lysis and the role of σ(E) in stationary phase, we investigated the effects of elevated σ(E) activity in cultures grown for ten days...
April 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28369099/comparative-gene-expression-analysis-of-porphyromonas-gingivalis-atcc-33277-in-planktonic-and-biofilms-states
#13
P Romero-Lastra, M C Sánchez, H Ribeiro-Vidal, A Llama-Palacios, E Figuero, D Herrera, M Sanz
BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis is a keystone pathogen in the onset and progression of periodontitis. Its pathogenicity has been related to its presence and survival within the subgingival biofilm. The aim of the present study was to compare the genome-wide transcription activities of P. gingivalis in biofilm and in planktonic growth, using microarray technology. MATERIAL AND METHODS: P. gingivalis ATCC 33277 was incubated in multi-well culture plates at 37°C for 96 hours under anaerobic conditions using an in vitro static model to develop both the planktonic and biofilm states (the latter over sterile ceramic calcium hydroxyapatite discs)...
2017: PloS One
https://www.readbyqxmd.com/read/28316480/inducible-spy-transcription-acts-as-a-sensor-for-envelope-stress-of-salmonella-typhimurium
#14
Seon Mi Jeong, Hwa Jeong Lee, Yoon Mee Park, Jin Seok Kim, Sang Dae Lee, Iel Soo Bang
Salmonella enterica infects a broad range of host animals, and zoonostic infection threatens both public health and the livestock and meat processing industries. Many antimicrobials have been developed to target Salmonella envelope that performs essential bacterial functions; however, there are very few analytical methods that can be used to validate the efficacy of these antimicrobials. In this study, to develop a potential biosensor for Salmonella envelope stress, we examined the transcription of the S. enterica serovar typhimurium spy gene, the ortholog of which in Escherichia coli encodes Spy (spheroplast protein y)...
2017: Korean Journal for Food Science of Animal Resources
https://www.readbyqxmd.com/read/28315278/peeking-into-sigma-1-receptor-functions-through-the-retina
#15
Timur A Mavlyutov, Lian-Wang Guo
This review discusses recent advances towards understanding the sigma-1 receptor (S1R) as an endogenous neuro-protective mechanism in the retina , a favorable experimental model system. The exquisite architecture of the mammalian retina features layered and intricately wired neurons supported by non-neuronal cells. Ganglion neurons, photoreceptors , as well as the retinal pigment epithelium, are susceptible to degeneration that leads to major retinal diseases such as glaucoma , diabetic retinopathy , and age-related macular degeneration (AMD), and ultimately, blindness...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28274217/disruption-of-rcsb-by-a-duplicated-sequence-in-a-curli-producing-escherichia-coli-o157-h7-results-in-differential-gene-expression-in-relation-to-biofilm-formation-stress-responses-and-metabolism
#16
V K Sharma, D O Bayles, D P Alt, T Looft, B W Brunelle, J A Stasko
BACKGROUND: Escherichia coli O157:H7 (O157) strain 86-24, linked to a 1986 disease outbreak, displays curli- and biofilm-negative phenotypes that are correlated with the lack of Congo red (CR) binding and formation of white colonies (CR(-)) on a CR-containing medium. However, on a CR medium this strain produces red isolates (CR(+)) capable of producing curli fimbriae and biofilms. RESULTS: To identify genes controlling differential expression of curli fimbriae and biofilm formation, the RNA-Seq profile of a CR(+) isolate was compared to the CR(-) parental isolate...
March 8, 2017: BMC Microbiology
https://www.readbyqxmd.com/read/28243135/repeated-short-climatic-change-affects-the-epidermal-differentiation-program-and-leads-to-matrix-remodeling-in-a-human-organotypic-skin-model
#17
Laetitia-Barbollat Boutrand, Amélie Thépot, Charlotte Muther, Aurélie Boher, Julie Robic, Christelle Guéré, Katell Vié, Odile Damour, Jérôme Lamartine
Human skin is subject to frequent changes in ambient temperature and humidity and needs to cope with these environmental modifications. To decipher the molecular response of human skin to repeated climatic change, a versatile model of skin equivalent subject to "hot-wet" (40°C, 80% relative humidity [RH]) or "cold-dry" (10°C, 40% RH) climatic stress repeated daily was used. To obtain an exhaustive view of the molecular mechanisms elicited by climatic change, large-scale gene expression DNA microarray analysis was performed and modulated function was determined by bioinformatic annotation...
2017: Clinical, Cosmetic and Investigational Dermatology
https://www.readbyqxmd.com/read/28183185/rational-design-of-selective-and-bioactive-inhibitors-of-the-mycobacterium-tuberculosis-proteasome
#18
Kyle A Totaro, Dominik Barthelme, Peter T Simpson, Xiuju Jiang, Gang Lin, Carl F Nathan, Robert T Sauer, Jason K Sello
The 20S core particle of the proteasome in Mycobacterium tuberculosis (Mtb) is a promising, yet unconventional, drug target. This multimeric peptidase is not essential, yet degrades proteins that have become damaged and toxic via reactions with nitric oxide (and/or the associated reactive nitrogen intermediates) produced during the host immune response. Proteasome inhibitors could render Mtb susceptible to the immune system, but they would only be therapeutically viable if they do not inhibit the essential 20S counterpart in humans...
February 10, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28161514/biosorption-behavior-and-proteomic-analysis-of-escherichia-coli-p4-under-cadmium-stress
#19
Zaman Khan, Abdul Rehman, Muhammad Atif Nisar, Saima Zafar, Inga Zerr
Bacteria develop a variety of adaptations at transcriptomic, metabolomic and proteomic levels in order to survive potentially damaging environmental perturbations. Present study is exploring the fluctuations in proteome of E. coli P4 to knob Cd(+2)-induced cytotoxicity. An attempt was also made to integrate all these approaches to gain comprehensive insight of Cd(+2) stress response in E. coli P4. This study is exposing the altered behavior of various proteins and their underlying metabolic pathways which have previously not been reported with reference to Cd(+2) stress such as sulfoquinovose biosynthesis and degradation pathway...
May 2017: Chemosphere
https://www.readbyqxmd.com/read/28065260/biochemical-characterization-of-function-and-structure-of-rsep-an-escherichia-coli-s2p-protease
#20
Y Hizukuri, K Akiyama, Y Akiyama
Intramembrane-cleaving proteases (I-CLiPs) are a group of membrane-associated proteases with a unique feature: they are believed to cleave their substrate within the hydrophobic lipid bilayer, even though peptide bond hydrolysis requires a water molecule. Escherichia coli RseP, which belongs to the S2P zinc metalloprotease family of I-CLiPs, plays an essential role in activation of a cell envelope stress response through cleavage of anti-σ(E) protein RseA, a single-span transmembrane protein. A recent study showed that it also cleaves remnant signal peptides generated upon membrane translocation of secretory proteins...
2017: Methods in Enzymology
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