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https://www.readbyqxmd.com/read/29621531/honeybee-apis-cerana-vitellogenin-acts-as-an-antimicrobial-and-antioxidant-agent-in-the-body-and-venom
#1
Hee Geun Park, Kwang Sik Lee, Bo Yeon Kim, Hyung Joo Yoon, Yong Soo Choi, Kyung Yong Lee, Hu Wan, Jianhong Li, Byung Rae Jin
Honeybee (Apis mellifera) egg-yolk protein vitellogenin (Vg) plays roles in immunity, antioxidation, and life span beyond reproduction, but it also acts as an allergen Api m 12 in venom. Here we established antimicrobial and antioxidant roles of honeybee Vg in the body and venom. Using the cDNA encoding Vg identified from Asiatic honeybee (A. cerana) workers, recombinant A. cerana Vg (AcVg) protein of approximately 180 kDa was produced in baculovirus-infected insect cells. In A. cerana worker bees, AcVg was expressed in the fat body and venom gland and was present in the secreted venom...
April 2, 2018: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/29579694/translocation-of-lipoproteins-to-the-surface-of-gram-negative-bacteria
#2
REVIEW
Yogesh Hooda, Trevor F Moraes
The surface of many Gram-negative bacteria contains lipidated protein molecules referred to as surface lipoproteins or SLPs. SLPs play critical roles in host immune evasion, nutrient acquisition and regulation of bacterial stress response, and have been extensively studied as vaccine antigens. The aim of this review is to summarize the recent studies that have investigated the biosynthetic and translocation pathways used by different bacterial species to deliver SLPs to the surface. We will specifically focus on Slam, a novel outer membrane protein first discovered in pathogenic Neisseria sp...
March 23, 2018: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/29576081/selenoprotein-o-is-a-chloroplast-protein-involved-in-ros-scavenging-and-its-absence-increases-dehydration-tolerance-in-arabidopsis-thaliana
#3
Yosef Fichman, Zsuzsa Koncz, Noam Reznik, Gad Miller, László Szabados, Katharina Kramer, Hirofumi Nakagami, Hillel Fromm, Csaba Koncz, Aviah Zilberstein
The evolutionary conserved family of Selenoproteins performs redox-regulatory functions in bacteria, archaea and eukaryotes. Among them, members of the SELENOPROTEIN O (SELO) subfamily are located in mammalian and yeast mitochondria, but their functions are thus far enigmatic. Screening of T-DNA knockout mutants for resistance to the proline analogue thioproline (T4C), identified mutant alleles of the plant SELO homologue in Arabidopsis thaliana. Absence of SELO resulted in a stress-induced transcriptional activation instead of silencing of mitochondrial proline dehydrogenase, and also high elevation of Δ(1)-pyrroline-5-carboxylate dehydrogenase involved in degradation of proline, thereby alleviating T4C inhibition and lessening drought-induced proline accumulation...
May 2018: Plant Science: An International Journal of Experimental Plant Biology
https://www.readbyqxmd.com/read/29565833/role-of-the-extremolytes-ectoine-and-hydroxyectoine-as-stress-protectants-and-nutrients-genetics-phylogenomics-biochemistry-and-structural-analysis
#4
REVIEW
Laura Czech, Lucas Hermann, Nadine Stöveken, Alexandra A Richter, Astrid Höppner, Sander H J Smits, Johann Heider, Erhard Bremer
Fluctuations in environmental osmolarity are ubiquitous stress factors in many natural habitats of microorganisms, as they inevitably trigger osmotically instigated fluxes of water across the semi-permeable cytoplasmic membrane. Under hyperosmotic conditions, many microorganisms fend off the detrimental effects of water efflux and the ensuing dehydration of the cytoplasm and drop in turgor through the accumulation of a restricted class of organic osmolytes, the compatible solutes. Ectoine and its derivative 5-hydroxyectoine are prominent members of these compounds and are synthesized widely by members of the Bacteria and a few Archaea and Eukarya in response to high salinity/osmolarity and/or growth temperature extremes...
March 22, 2018: Genes
https://www.readbyqxmd.com/read/29535688/conceptual-perspectives-bacterial-antimicrobial-peptide-induction-as-a-novel-strategy-for-symbiosis-with-the-human-host
#5
Santosh K Ghosh, Zhimin Feng, Hisashi Fujioka, Renate Lux, Thomas S McCormick, Aaron Weinberg
Human beta defensins (hBDs) are small cationic peptides, expressed in mucosal epithelia and important agents of innate immunity, act as antimicrobial and chemotactic agents at mucosal barriers. In this perspective, we present evidence supporting a novel strategy by which the oral bacterium Fusobacterium nucleatum induces hBDs and other antimicrobial peptides (AMPs) in normal human oral epithelial cells (HOECs) and thereby protects them from other microbial pathogens. The findings stress (1) the physiological importance of hBDs, (2) that this strategy may be a mechanism that contributes to homeostasis and health in body sites constantly challenged with bacteria and (3) that novel properties identified in commensal bacteria could, one day, be harnessed as new probiotic strategies to combat colonization of opportunistic pathogens...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29530765/complete-genome-sequence-of-pseudomonas-frederiksbergensis-erdd5-01-revealed-genetic-bases-for-survivability-at-high-altitude-ecosystem-and-bioprospection-potential
#6
Rakshak Kumar, Vishal Acharya, Srijana Mukhia, Dharam Singh, Sanjay Kumar
Pseudomonas frederiksbergensis ERDD5:01 is a psychrotrophic bacteria isolated from the glacial stream flowing from East Rathong glacier in Sikkim Himalaya. The strain showed survivability at high altitude stress conditions like freezing, frequent freeze-thaw cycles, and UV-C radiations. The complete genome of 5,746,824 bp circular chromosome and a plasmid of 371,027 bp was sequenced to understand the genetic basis of its survival strategy. Multiple copies of cold-associated genes encoding cold active chaperons, general stress response, osmotic stress, oxidative stress, membrane/cell wall alteration, carbon storage/starvation and, DNA repair mechanisms supported its survivability at extreme cold and radiations corroborating with the bacterial physiological findings...
March 9, 2018: Genomics
https://www.readbyqxmd.com/read/29516880/proteomic-analysis-of-hydroxyl-radical-induced-resuscitation-of-hypoxia-induced-dormant-mycobacterial-cells
#7
Abhishek Mishra
Background: The genus Mycobacterium has an ability to persist in hostile environments for years before its reactivation in favorable conditions. The major bottleneck in decades of mycobacterial research is a poor understanding of molecular mechanism which assists bacteria to attain dormancy and reactivation later. Methods: In this study, hydroxyl radical was quantified in aerobically growing mycobacterial cells using 2-deoxy-D-ribose assay. Furthermore, extraneous addition of hydroxyl radical in Wayne's dormancy model induced reactivation of dormant cells...
January 2018: International Journal of Mycobacteriology
https://www.readbyqxmd.com/read/29515552/the-cyanobacterium-cylindrospermopsis-raciborskii-cyrf-01-responds-to-environmental-stresses-with-increased-vesiculation-detected-at-single-cell-resolution
#8
Victor Zarantonello, Thiago P Silva, Natália P Noyma, Juliana P Gamalier, Mariana M Mello, Marcelo M Marinho, Rossana C N Melo
Secretion of membrane-limited vesicles, collectively termed extracellular vesicles (EVs), is an important biological process of both eukaryotic and prokaryotic cells. This process has been observed in bacteria, but remains to be better characterized at high resolution in cyanobacteria. In the present work, we address the release of EVs by Cylindrospermopsis raciborskii (CYRF-01), a filamentous bloom-forming cyanobacterium, exposed to environmental stressors. First, non-axenic cultures of C. raciborskii (CYRF-01) were exposed to ultraviolet radiation (UVA + UVB) over a 6 h period, which is known to induce structural damage to this species...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29491145/disulfide-isomerase-activity-of-the-dynamic-trimeric-proteus-mirabilis-scsc-protein-is-primed-by-the-tandem-immunoglobulin-fold-domain-of-scsb
#9
Emily J Furlong, Hassanul G Choudhury, Fabian Kurth, Anthony P Duff, Andrew E Whitten, Jennifer L Martin
Correct disulfide bond formation is essential for proper folding of many proteins, including bacterial virulence factors. The suppressor of copper sensitivity (Scs) proteins have roles in dithiol/disulfide interchange and the bacterial response to copper stress. Encoded in a four-gene cassette (ScsABCD) present in many Gram-negative bacteria, the Scs proteins are enigmatic and poorly characterised. Here, we show that the periplasmic α domain of the membrane protein ScsB in the Gram-negative bacterium Proteus mirabilis forms a redox relay with the soluble periplasmic protein PmScsC...
February 28, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29488183/variations-on-a-theme-evolution-of-the-phage-shock-protein-system-in-actinobacteria
#10
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
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
Aoife M Colgan, Heather J Quinn, Stefani C Kary, Lesley A Mitchenall, Anthony Maxwell, Andrew D S Cameron, Charles J Dorman
DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4-5) macrophage vacuole and DNA relaxation correlates with the 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...
March 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
#20
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 Escherichia coli growth followed by selection of compounds that induced the extracytoplasmic σE stress response...
April 2018: Antimicrobial Agents and Chemotherapy
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