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https://www.readbyqxmd.com/read/29101308/impact-of-bacterial-srnas-in-stress-responses
#1
REVIEW
Erik Holmqvist, E Gerhart H Wagner
Bacterial life is harsh and involves numerous environmental and internal challenges that are perceived as stresses. Consequently, adequate responses to survive, cope with, and counteract stress conditions have evolved. In the last few decades, a class of small, non-coding RNAs (sRNAs) has been shown to be involved as key players in stress responses. This review will discuss - primarily from an enterobacterial perspective - selected stress response pathways that involve antisense-type sRNAs. These include themes of how bacteria deal with severe envelope stress, threats of DNA damage, problems with poisoning due to toxic sugar intermediates, issues of iron homeostasis, and nutrient limitation/starvation...
November 3, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/29098331/essential-two-component-systems-regulating-cell-envelope-functions-opportunities-for-novel-antibiotic-therapies
#2
Silvia T Cardona, Matthew Choy, Andrew M Hogan
Novel therapies are urgently needed to alleviate the current crisis of multiple drug-resistant infections. The bacterial signal transduction mechanisms, known as two-component systems (TCSs), are ideal targets of novel inhibitory molecules. Highly restricted to the bacterial world, TCSs control a diverse set of cellular functions, namely virulence, response to cell envelope stress, and drug efflux. Impaired regulation of any of these aspects could affect the susceptibility of bacterial pathogens to antibiotics, which highlights the potential of TCS as targets of antibiotic adjuvant therapies...
November 2, 2017: Journal of Membrane Biology
https://www.readbyqxmd.com/read/29043249/interactions-between-bacteria-and-bile-salts-in-the-gastrointestinal-and-hepatobiliary-tracts
#3
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
#4
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/29020117/a-putative-vibrio-cholerae-two-component-system-controls-a-conserved-periplasmic-protein-in-response-to-the-antimicrobial-peptide-polymyxin-b
#5
Jyl S Matson, Jonathan Livny, Victor J DiRita
The epidemic pathogen Vibrio cholerae senses and responds to different external stresses it encounters in the aquatic environment and in the human host. One stress that V. cholerae encounters in the host is exposure to antimicrobial peptides on mucosal surfaces. We used massively parallel cDNA sequencing (RNA-Seq) to quantitatively identify the transcriptome of V. cholerae grown in the presence and absence of sub-lethal concentrations of the antimicrobial peptide polymyxin B. We evaluated the transcriptome of both wild type V...
2017: PloS One
https://www.readbyqxmd.com/read/28992090/mechanical-properties-of-cuticles-and-their-primary-determinants
#6
Bishnu P Khanal, Moritz Knoche
Cuticles envelope primary surfaces of the above-ground portion of plants. They function as barriers to water movement and to gas exchange, and in pathogen defense. To serve as a barrier on growing organs, cuticles must remain intact but at the same time must accommodate ongoing growth. Minimizing cuticle failure has stimulated significant research on the cuticle's mechanical properties. The objective here is to review the literature on the mechanical properties of isolated fruit and leaf cuticles. Cuticles are viscoelastic polymers...
November 9, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28984364/isolation-and-analysis-of-a-stromule-overproducing-arabidopsis-mutant-suggest-the-role-of-parc6-in-plastid-morphology-maintenance-in-the-leaf-epidermis
#7
Ryuuichi D Itoh, Hiroki Ishikawa, Kohdai P Nakajima, Shota Moriyama, Makoto T Fujiwara
Stromules, or stroma-filled tubules, are thin extensions of the plastid envelope membrane that are most frequently observed in undifferentiated or non-mesophyll cells. The formation of stromules is developmentally regulated and responsive to biotic and abiotic stress; however, the physiological roles and molecular mechanisms of the stromule formation remain enigmatic. Accordingly, we attempted to obtain Arabidopsis thaliana mutants with aberrant stromule biogenesis in the leaf epidermis. Here, we characterize one of the obtained mutants...
October 6, 2017: Physiologia Plantarum
https://www.readbyqxmd.com/read/28947671/a-small-periplasmic-protein-with-a-hydrophobic-c-terminal-residue-enhances-degp-proteolysis-as-a-suicide-activator
#8
Sungjae Kim, Inseok Song, Gaeul Eom, Seokhee Kim
DegP is a highly conserved protease that performs regulated proteolysis to selectively remove misfolded proteins in the periplasm of Escherichia coli Binding of misfolded proteins is known to be the main mechanism of DegP activation, but it is unknown whether any native proteins can alter DegP activity. Here, we show that a small periplasmic protein, YjfN, which is highly upregulated by the Cpx envelope stress response, functions as a "suicide activator" for DegP and promotes efficient degradation of misfolded proteins...
September 25, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28944132/rapid-shelf-wide-cooling-response-of-a-stratified-coastal-ocean-to-hurricanes
#9
Greg Seroka, Travis Miles, Yi Xu, Josh Kohut, Oscar Schofield, Scott Glenn
Large uncertainty in the predicted intensity of tropical cyclones (TCs) persists compared to the steadily improving skill in the predicted TC tracks. This intensity uncertainty has its most significant implications in the coastal zone, where TC impacts to populated shorelines are greatest. Recent studies have demonstrated that rapid ahead-of-eye-center cooling of a stratified coastal ocean can have a significant impact on hurricane intensity forecasts. Using observation-validated, high-resolution ocean modeling, the stratified coastal ocean cooling processes observed in two U...
June 2017: Journal of Geophysical Research. Oceans
https://www.readbyqxmd.com/read/28943871/global-screening-of-salmonella-enterica-serovar-typhimurium-genes-for-desiccation-survival
#10
Rabindra K Mandal, Young M Kwon
Salmonella spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of Salmonella infection in humans associated with low water activity foods. Salmonella responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of Salmonella to resist desiccation stress remain to be fully elucidated...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28942523/overexpression-of-plastidic-maize-nadp-malate-dehydrogenase-zmnadp-mdh-in-arabidopsis-thaliana-confers-tolerance-to-salt-stress
#11
Deepika Kandoi, Sasmita Mohanty, Baishnab C Tripathy
The plastidic C4 Zea mays NADP-malate dehydrogenase (ZmNADP-MDH), responsible for catalysis of oxaloacetate to malate, was overexpressed in Arabidopsis thaliana to assess its impact on photosynthesis and tolerance to salinity stress. Different transgenic lines were produced having ~3-6-fold higher MDH protein abundance and NADP-MDH enzyme activity than vector control. The overexpressors had similar chlorophyll, carotenoid, and protein content as that of vector control. Their photosynthetic electron transport rates, carbon assimilation rate, and consequently fresh weight and dry weight were almost similar...
September 24, 2017: Protoplasma
https://www.readbyqxmd.com/read/28925518/chemistry-of-peptidoglycan-in-mycobacterium-tuberculosis-life-style-an-off-the-wall-balance-of-synthesis-and-degradation
#12
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/28924029/circuitry-linking-the-global-csr-and-%C3%AF-e-dependent-cell-envelope-stress-response-systems
#13
Helen Yakhnin, Robert Aichele, Sarah E Ades, Tony Romeo, Paul Babitzke
CsrA of Escherichia coli is an RNA-binding protein that globally regulates a wide variety of cellular processes and behaviors including carbon metabolism, motility, biofilm formation, and the stringent response. CsrB and CsrC are sRNAs that sequester CsrA, thereby preventing CsrA-mRNA interaction. RpoE (σ(E)) is the extracytoplasmic stress response sigma factor of E. coli Previous RNA-seq studies identified rpoE mRNA as a CsrA target. Here we explored the regulation of rpoE by CsrA and found that CsrA represses rpoE translation...
September 18, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28922502/the-three-component-system-esrisr-regulates-a-cell-envelope-stress-response-in-corynebacterium-glutamicum
#14
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/28910825/comparison-of-continuous-wave-and-micropulse-modulation-in-retinal-laser-therapy
#15
COMPARATIVE STUDY
Jenny Wang, Yi Quan, Roopa Dalal, Daniel Palanker
Purpose: Recent progress in retinal laser therapy has centered upon using thermal stress below damage threshold or selective destruction of targeted tissue layers as a stimulus for retinal repair. Temporal modulation, including micropulse, is thought to increase the selectivity of laser treatment, but has not been carefully analyzed. We measure and model the tissue response to continuous-wave (CW) and micropulse laser to evaluate the advantages and drawbacks of temporal modulation. Methods: Thresholds of ophthalmoscopic visibility, which indicates damage to photoreceptors, and fluorescein angiography (FA), indicating damage to retinal pigment epithelium (RPE), were measured with 577-nm laser in rabbits for duty cycles ranging from 3% to 100% (CW) and pulse envelopes of 20 and 200 ms...
September 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28906045/actinorhodin-is-a-redox-active-antibiotic-with-a-complex-mode-of-action-against-gram-positive-cells
#16
Stefanie Mak, Justin R Nodwell
Actinorhodin is a blue-pigmented, redox-active secondary metabolite that is produced by the bacterium Streptomyces coelicolor. Although actinorhodin has been used as a model compound for studying secondary metabolism, its biological activity is not well understood. Indeed, redox-active antibiotics in general have not been widely investigated at the mechanistic level. In this work, we have conducted a comprehensive chemical genetic investigation of actinorhodin's antibacterial effect on target organisms. We find that actinorhodin is a potent, bacteriostatic, pH-responsive antibiotic...
September 14, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28883824/natural-killer-nk-cell-education-differentially-influences-hiv-antibody-dependent-nk-cell-activation-and-antibody-dependent-cellular-cytotoxicity
#17
REVIEW
Nicole F Bernard, Zahra Kiani, Alexandra Tremblay-McLean, Sanket A Kant, Christopher E Leeks, Franck P Dupuy
Immunotherapy using broadly neutralizing antibodies (bNAbs) endowed with Fc-mediated effector functions has been shown to be critical for protecting or controlling viral replication in animal models. In human, the RV144 Thai trial was the first trial to demonstrate a significant protection against HIV infection following vaccination. Analysis of the correlates of immune protection in this trial identified an association between the presence of antibody-dependent cellular cytotoxicity (ADCC) mediated by immunoglobulin G (IgG) antibodies (Abs) to HIV envelope (Env) V1/V2 loop structures and protection from infection, provided IgA Abs with competing specificity were not present...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28875939/within-host-envelope-remodelling-and-its-impact-in-bacterial-pathogen-recognition
#18
M Graciela Pucciarelli, Francisco García-Del Portillo
Following colonization of host tissues, bacterial pathogens encounter new niches in which they must gain access to nutrients and cope with stresses and defence signals generated by the host. For some pathogens, the adaptation to a new 'within-host' lifestyle involves modifications of envelope components that bear molecular patterns normally recognized by the host innate immune system. These new modified patterns limit host recognition, therefore promoting immune evasion and pathogenicity. In this review, we describe how envelope components like the peptidoglycan or lipopolysaccharide can be altered within the host to impair responses triggered by pattern recognition receptors (PRR)...
September 6, 2017: Current Issues in Molecular Biology
https://www.readbyqxmd.com/read/28874409/extracellular-salb-contributes-to-intrinsic-cephalosporin-resistance-and-cell-envelope-integrity-in-enterococcus-faecalis
#19
Dušanka Djorić, Christopher J Kristich
Enterococci are major causes of hospital-acquired infections. Intrinsic resistance to cephalosporins is a universal trait among clinically relevant enterococci. Cephalosporin resistance enables enterococci to proliferate to high densities in the intestines of patients undergoing cephalosporin treatment, a precursor to the emergence of infection. However, the genetic and biochemical mechanisms of intrinsic cephalosporin resistance in enterococci are not well understood. A two-component signal transduction system, CroR/S, is required for cephalosporin resistance in enterococci...
September 5, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28854955/identification-of-two-mutation-sites-in-spike-and-envelope-proteins-mediating-optimal-cellular-infection-of-porcine-epidemic-diarrhea-virus-from-different-pathways
#20
Min Sun, Jiale Ma, Zeyanqiu Yu, Zihao Pan, Chengping Lu, Huochun Yao
Entry of the α-coronavirus porcine epidemic diarrhea virus (PEDV) requires specific proteases to activate spike (S) protein for the membrane fusion of the virion to the host cell following receptor binding. Herein, PEDV isolate 85-7 could proliferate and induce cell-cell fusion in a trypsin independent manner on Vero cells, and eight homologous mutation strains were screened by continuous proliferation in the absence of trypsin on Vero cells. According to the whole genome sequence comparative analysis, we identified four major variations located in nonstructural protein 2, S, open reading frame 3, and envelope (E) genes, respectively...
August 30, 2017: Veterinary Research
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