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https://www.readbyqxmd.com/read/28721843/treponema-rectale-sp-nov-a-spirochete-isolated-from-the-bovine-rectum
#1
Gareth J Staton, Kerry Newbrook, Simon R Clegg, Richard J Birtles, Nicholas J Evans, Stuart D Carter
A Gram-stain-negative, obligatory anaerobic spirochete, CHPAT, was isolated from the rectal tissue of a Holstein-Friesian cow. On the basis of 16S rRNA gene comparisons, CHPAT was most closely related to the human oral spirochete, Treponema parvum, with 88.8 % sequence identity. Further characterisation on the basis of recA gene sequence analysis, cell morphology, pattern of growth and physiological profiling identified marked differences with respect to other recognised species of the genus Treponema. Microscopically, the helical cells measured approximately 1-5 µm long and 0...
July 18, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28721045/synthesis-construction-and-evaluation-of-self-assembled-nano-bacitracin-a-as-an-efficient-antibacterial-agent-in-vitro-and-in-vivo
#2
Wei Hong, Xiang Gao, Peng Qiu, Jie Yang, Mingxi Qiao, Hong Shi, Dexian Zhang, Chunlian Tian, Shengli Niu, Mingchun Liu
Bacitracin A (BA) is an excellent polypeptide antibiotic that is active against gram-positive bacteria without triggering multidrug resistance. However, BA is inactive against gram-negative bacteria because of its inability to cross the outer membrane of these cells, and it has strong nephrotoxicity, thus limiting its clinical applications. Nanoantibiotics can effectively localize antibiotics to the periplasmic space of bacteria while decreasing the adverse effects of antibiotics. In this study, biodegradable hydrophobic copolymers of poly (d,l-lactide-co-glycolide) (PLGA) were attached to the N-termini of BA to design a novel class of self-assembled nano-bacitracin A (nano-BAs), and their potential as antibacterial agents was evaluated in vitro and in vivo...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28720728/disguised-as-a-sulfate-reducer-growth-of-the-deltaproteobacterium-desulfurivibrio-alkaliphilus-by-sulfide-oxidation-with-nitrate
#3
Casper Thorup, Andreas Schramm, Alyssa J Findlay, Kai W Finster, Lars Schreiber
This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28719308/a-recombinant-47-kda-outer-membrane-protein-induces-an-immune-response-against-orientia-tsutsugamushi-strain-boryong
#4
Sangho Choi, Hang Jin Jeong, Kyu-Jam Hwang, Byoungchul Gill, Young Ran Ju, Yeong Seon Lee, Jeongmin Lee
We investigated the 47-kDa outer membrane protein (OMP), which is a periplasmic serine protease and an antigenic major surface protein of Orientia tsutsugamushi, as a vaccine candidate. We developed a conventional subunit vaccine expressing recombinant 47-kDa OMP (rec47) and a DNA vaccine (p47). In mouse immunization experiments, intranasal immunization with rec47 alone or with rec47 plus heat-labile enterotoxin B subunit from Escherichia coli or plus cholera toxin (CT) as adjuvants induced a higher amount of rec47-specific antibodies than intramuscular immunization with p47 alone or with p47 plus pBOOST2-samIRF7/3 (pB) as adjuvant...
July 2017: American Journal of Tropical Medicine and Hygiene
https://www.readbyqxmd.com/read/28716923/molecular-mechanism-of-environmental-d-xylose-perception-by-a-xylfii-lyts-complex-in-bacteria
#5
Jianxu Li, Chengyuan Wang, Gaohua Yang, Zhe Sun, Hui Guo, Kai Shao, Yang Gu, Weihong Jiang, Peng Zhang
d-xylose, the main building block of plant biomass, is a pentose sugar that can be used by bacteria as a carbon source for bio-based fuel and chemical production through fermentation. In bacteria, the first step for d-xylose metabolism is signal perception at the membrane. We previously identified a three-component system in Firmicutes bacteria comprising a membrane-associated sensor protein (XylFII), a transmembrane histidine kinase (LytS) for periplasmic d-xylose sensing, and a cytoplasmic response regulator (YesN) that activates the transcription of the target ABC transporter xylFGH genes to promote the uptake of d-xylose...
July 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28715501/diversity-and-distribution-of-nuclease-bacteriocins-in-bacterial-genomes-revealed-using-hidden-markov-models
#6
Connor Sharp, James Bray, Nicholas G Housden, Martin C J Maiden, Colin Kleanthous
Bacteria exploit an arsenal of antimicrobial peptides and proteins to compete with each other. Three main competition systems have been described: type six secretion systems (T6SS); contact dependent inhibition (CDI); and bacteriocins. Unlike T6SS and CDI systems, bacteriocins do not require contact between bacteria but are diffusible toxins released into the environment. Identified almost a century ago, our understanding of bacteriocin distribution and prevalence in bacterial populations remains poor. In the case of protein bacteriocins, this is because of high levels of sequence diversity and difficulties in distinguishing their killing domains from those of other competition systems...
July 17, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28708324/ferrichrome-has-found-its-match-biomimetic-analogs-with-diversified-activity-map-discrete-microbial-targets
#7
Jenny Besserglick, Evgenia Olshvang, Agnieszka Szebesczyk, Joseph Englander, Dana Levinson, Yitzhak Hadar, Elzbieta Gumienna-Kontecka, Abraham Shanzer
Siderophores provide an established platform for studying molecular recognition principles in biological systems. Herein we describe the preparation of ferrichrome biomimetic analogs varying in length and polarity of the amino acid chain separating between the tripodal scaffold and the pendent FeIII chelating hydroxamic acid groups. Spectroscopic and potentiometric titrations determined their iron affinity to be within the range of efficient chelators. Microbial growth promotion and iron uptake studies were conducted on E...
July 14, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28699183/how-bacterial-cell-division-might-cheat-turgor-pressure-a-unified-mechanism-of-septal-division-in-gram-positive-and-gram-negative-bacteria
#8
REVIEW
Harold P Erickson
An important question for bacterial cell division is how the invaginating septum can overcome the turgor force generated by the high osmolarity of the cytoplasm. I suggest that it may not need to. Several studies in Gram-negative bacteria have shown that the periplasm is isoosmolar with the cytoplasm. Indirect evidence suggests that this is also true for Gram-positive bacteria. In this case the invagination of the septum takes place within the uniformly high osmotic pressure environment, and does not have to fight turgor pressure...
July 12, 2017: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
https://www.readbyqxmd.com/read/28698362/structural-insights-into-lipoprotein-n-acylation-by-escherichia-coli-apolipoprotein-n-acyltransferase
#9
Cameron L Noland, Michele D Kattke, Jingyu Diao, Susan L Gloor, Homer Pantua, Mike Reichelt, Anand K Katakam, Donghong Yan, Jing Kang, Inna Zilberleyb, Min Xu, Sharookh B Kapadia, Jeremy M Murray
Gram-negative bacteria express a diverse array of lipoproteins that are essential for various aspects of cell growth and virulence, including nutrient uptake, signal transduction, adhesion, conjugation, sporulation, and outer membrane protein folding. Lipoprotein maturation requires the sequential activity of three enzymes that are embedded in the cytoplasmic membrane. First, phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) recognizes a conserved lipobox motif within the prolipoprotein signal sequence and catalyzes the addition of diacylglycerol to an invariant cysteine...
July 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28696311/escherichia-coli-cytochrome-c-peroxidase-is-a-respiratory-oxidase-that-enables-the-use-of-hydrogen-peroxide-as-a-terminal-electron-acceptor
#10
Maryam Khademian, James A Imlay
Microbial cytochrome c peroxidases (Ccp) have been studied for 75 years, but their physiological roles are unclear. Ccps are located in the periplasms of bacteria and the mitochondrial intermembrane spaces of fungi. In this study, Ccp is demonstrated to be a significant degrader of hydrogen peroxide in anoxic Escherichia coli Intriguingly, ccp transcription requires both the presence of H2O2 and the absence of O2 Experiments show that Ccp lacks enough activity to shield the cytoplasm from exogenous H2O2 However, it receives electrons from the quinone pool, and its flux rate approximates flow to other anaerobic electron acceptors...
July 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28696280/nontypeable-haemophilus-influenzae-releases-dna-and-dnabii-proteins-via-a-t4ss-like-complex-and-come-of-the-type-iv-pilus-machinery
#11
Joseph A Jurcisek, Kenneth L Brockman, Laura A Novotny, Steven D Goodman, Lauren O Bakaletz
Biofilms formed by nontypeable Haemophilus influenzae (NTHI) are central to the chronicity, recurrence, and resistance to treatment of multiple human respiratory tract diseases including otitis media, chronic rhinosinusitis, and exacerbations of both cystic fibrosis and chronic obstructive pulmonary disease. Extracellular DNA (eDNA) and associated DNABII proteins are essential to the overall architecture and structural integrity of biofilms formed by NTHI and all other bacterial pathogens tested to date. Although cell lysis and outer-membrane vesicle extrusion are possible means by which these canonically intracellular components might be released into the extracellular environment for incorporation into the biofilm matrix, we hypothesized that NTHI additionally used a mechanism of active DNA release...
July 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28695856/crystal-structure-of-yersinia-pestis-virulence-factor-yfea-reveals-two-polyspecific-metal-binding-sites
#12
Christopher D Radka, Lawrence J DeLucas, Landon S Wilson, Matthew B Lawrenz, Robert D Perry, Stephen G Aller
Gram-negative bacteria use siderophores, outer membrane receptors, inner membrane transporters and substrate-binding proteins (SBPs) to transport transition metals through the periplasm. The SBPs share a similar protein fold that has undergone significant structural evolution to communicate with a variety of differentially regulated transporters in the cell. In Yersinia pestis, the causative agent of plague, YfeA (YPO2439, y1897), an SBP, is important for full virulence during mammalian infection. To better understand the role of YfeA in infection, crystal structures were determined under several environmental conditions with respect to transition-metal levels...
July 1, 2017: Acta Crystallographica. Section D, Structural Biology
https://www.readbyqxmd.com/read/28692133/new-insights-into-enterocin-crl35-mechanism-of-action-and-immunity-revealed-by-heterologous-expression-in-escherichia-coli
#13
Daniela E Barraza, Natalia S Ríos Colombo, Adriana E Galván, Leonardo Acuña, Carlos J Minahk, Augusto Bellomio, Miriam C Chalón
The role of the class IIa bacteriocin membrane receptor protein remains unclear and two different mechanisms have been proposed: the bacteriocin could interact with the receptor changing it to an open conformation or the receptor might act as an anchor allowing subsequent bacteriocin insertion and membrane disruption. Bacteriocin-producing cells synthesize an immunity protein that forms an inactive bacteriocin-receptor-immunity complex. To better understand the molecular mechanism of enterocin CRL35, the peptide was expressed as the suicidal probe EtpM-enterocin CRL35 in Escherichia coli, a naturally insensitive microorganism since it does not express the receptor...
July 10, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28691662/role-of-the-inner-membrane-histidine-kinase-rcsc-and-outer-membrane-lipoprotein-rcsf-in-the-activation-of-the-rcs-phosphorelay-signal-transduction-system-in-escherichia-coli
#14
Takatsugu Sato, Akira Takano, Nanako Hori, Tomoko Izawa, Takayoshi Eda, Kota Sato, Mitsuru Umekawa, Hiroyoshi Miyagawa, Kenji Matsumoto, Ayako Muramatsu-Fujishiro, Kouji Matsumoto, Satoshi Matsuoka, Hiroshi Hara
The Rcs phosphorelay signal transduction system of Escherichia coli controls genes for capsule production and many other envelope-related functions and is implicated in biofilm formation. The outer-membrane lipoprotein RcsF is an essential component of the Rcs system. Mislocalization of RcsF to the periplasm or the cytoplasmic membrane leads to high activation of the Rcs system, suggesting that RcsF functions by interacting with the cytoplasmic membrane component(s) of the system in activating the system. This is consistent with the result reported by Cho et al...
July 8, 2017: Microbiology
https://www.readbyqxmd.com/read/28687647/the-deep-sea-bacterium-shewanella-piezotolerans-wp3-has-two-dmso-reductases-in-distinct-subcellular-locations
#15
Lei Xiong, Huahua Jian, Xiang Xiao
Dimethyl sulfoxide (DMSO) acts as a substantial sink for dimethyl sulfide (DMS) in deep waters and is therefore considered a potential electron acceptor supporting abyssal ecosystems. Shewanella piezotolerans WP3 was isolated from west Pacific deep-sea sediments, and two functional DMSO respiratory subsystems are essential for maximum growth of WP3 under in situ conditions (4°C/20 MPa). However, the relationship between these two subsystems and the electron transport pathway underlying DMSO reduction by WP3 remain unknown...
July 7, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28678862/pseudomonas-aeruginosa-cells-attached-to-a-surface-display-a-typical-proteome-early-as-20-minutes-of-incubation
#16
Marc Crouzet, Stéphane Claverol, Anne-Marie Lomenech, Caroline Le Sénéchal, Patricia Costaglioli, Christophe Barthe, Bertrand Garbay, Marc Bonneu, Sébastien Vilain
Biofilms are present in all environments and often result in negative effects due to properties of the biofilm lifestyle and especially antibiotics resistance. Biofilms are associated with chronic infections. Controlling bacterial attachment, the first step of biofilm formation, is crucial for fighting against biofilm and subsequently preventing the persistence of infection. Thus deciphering the underlying molecular mechanisms involved in attachment could allow discovering molecular targets from it would be possible to develop inhibitors against bacterial colonization and potentiate antibiotherapy...
2017: PloS One
https://www.readbyqxmd.com/read/28675161/structural-insights-into-the-mechanism-of-the-membrane-integral-n-acyltransferase-step-in-bacterial-lipoprotein-synthesis
#17
Maciej Wiktor, Dietmar Weichert, Nicole Howe, Chia-Ying Huang, Vincent Olieric, Coilín Boland, Jonathan Bailey, Lutz Vogeley, Phillip J Stansfeld, Nienke Buddelmeijer, Meitian Wang, Martin Caffrey
Lipoproteins serve essential roles in the bacterial cell envelope. The posttranslational modification pathway leading to lipoprotein synthesis involves three enzymes. All are potential targets for the development of new antibiotics. Here we report the crystal structure of the last enzyme in the pathway, apolipoprotein N-acyltransferase, Lnt, responsible for adding a third acyl chain to the lipoprotein's invariant diacylated N-terminal cysteine. Structures of Lnt from Pseudomonas aeruginosa and Escherichia coli have been solved; they are remarkably similar...
July 4, 2017: Nature Communications
https://www.readbyqxmd.com/read/28674070/bacillus-subtilis-intramembrane-protease-rasp-activity-in-escherichia-coli-and-in-vitro
#18
Daniel Parrell, Yang Zhang, Sandra Olenic, Lee Kroos
RasP is a predicted intramembrane metalloprotease of Bacillus subtilis that has been proposed to cleave the stress response anti-sigma factors RsiW and RsiV, the cell division protein FtsL, and remnant signal peptides, within their transmembrane segments. To provide evidence for direct effects of RasP on putative substrates, we developed a heterologous coexpression system. Since expression of catalytically-inactive RasP E21A inhibited expression of other membrane proteins in Escherichia coli, we added extra transmembrane segments to RasP E21A, which allowed accumulation of most other membrane proteins...
July 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28674069/cyclic-di-gmp-and-vpsr-induce-the-expression-of-type-ii-secretion-in-vibrio-cholerae
#19
Rudolph E Sloup, Ashley E Konal, Geoffrey B Severin, Michelle L Korir, Mira M Bagdasarian, Michael Bagdasarian, Christopher M Waters
Vibrio cholerae is a human pathogen which alternates between growth in environmental reservoirs and infection of human hosts causing severe diarrhea. The second messenger cyclic di-GMP (c-di-GMP) mediates this transition by controlling a wide range of functions such as biofilms, virulence, and motility. Here we report that c-di-GMP induces expression of the extracellular protein secretion (eps) gene cluster, which encodes the Type II Secretion System (T2SS) in V. cholerae Analysis of the eps genes confirmed the presence of two promoters located upstream of epsC, the first gene in the operon, one of which is induced by c-di-GMP...
July 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28674068/structural-and-functional-analysis-of-the-escherichia-coli-acid-sensing-histidine-kinase-evgs
#20
Hrishiraj Sen, Nikhil Aggarwal, Chibueze Ishionwu, Nosheen Hussain, Chandni Parmar, Mohammed Jamshad, Vassiliy N Bavro, Peter A Lund
The EvgS/EvgA two component system of E. coli is activated in response to low pH and alkali metals, and regulates many genes including the glutamate dependent acid resistance system and a number of efflux pumps. EvgS, the sensor kinase, is one of five unconventional histidine kinases in E. coli, and has a large periplasmic domain and a cytoplasmic PAS domain in addition to phospho-acceptor, HK and dimerization, internal receiver, and phosphotransfer domains. Mutations that constitutively activate the protein at pH 7 map to the PAS domain...
July 3, 2017: Journal of Bacteriology
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