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https://www.readbyqxmd.com/read/28040856/dissecting-the-role-of-ntrc-and-rpon-in-the-expression-of-assimilatory-nitrate-and-nitrite-reductases-in-bradyrhizobium-diazoefficiens
#1
María F López, Juan J Cabrera, Ana Salas, María J Delgado, Silvina L López-García
Bradyrhizobium diazoefficiens, a nitrogen-fixing endosymbiont of soybeans, is a model strain for studying rhizobial denitrification. This bacterium can also use nitrate as the sole nitrogen (N) source during aerobic growth by inducing an assimilatory nitrate reductase encoded by nasC located within the narK-bjgb-flp-nasC operon along with a nitrite reductase encoded by nirA at a different chromosomal locus. The global nitrogen two-component regulatory system NtrBC has been reported to coordinate the expression of key enzymes in nitrogen metabolism in several bacteria...
December 31, 2016: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28040562/enzootic-origins-for-clinical-manifestations-of-lyme-borreliosis
#2
Setareh Jahfari, Aleksandra Krawczyk, E Claudia Coipan, Manoj Fonville, Joppe W Hovius, Hein Sprong, Katsuhisa Takumi
Both early localized and late disseminated forms of Lyme borreliosis are caused by Borrelia burgdorferi senso lato. Differentiating between the spirochetes that only cause localized skin infection from those that cause disseminated infection, and tracing the group of medically-important spirochetes to a specific vertebrate host species, are two critical issues in disease risk assessment and management. Borrelia burgdorferi senso lato isolates from Lyme borreliosis cases with distinct clinical manifestations (erythema migrans, neuroborreliosis, acrodermatitis chronica atrophicans, and Lyme arthritis) and isolates from Ixodes ricinus ticks feeding on rodents, birds and hedgehogs were typed to the genospecies level by sequencing part of the intergenic spacer region...
December 28, 2016: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28031123/-preparation-of-polyclonal-antibody-against-recombinant-sigma-54-protein-from-helicobacter-pylori
#3
Shuang Liu
Objective To express and purify recombinant sigma(54) protein of Helicobacter pylori, and prepare polyclonal antibody against sigma(54) protein. Methods Intact rpoN gene fragment was amplified from Helicobacter pylori (H. pylori) 26695 genome, and then cloned into prokaryotic expression vector pTriEx(TM)-4 with (6)His coding sequence. The recombinant plasmid was transformed into E.coli JM109DE. The recombinant protein with 6-His tag was expressed by IPTG induction and purified by His-Bind affinity columns. The purified protein supplemented with adjuvant was used to immunize rabbits to obtain the polyclonal antibody...
January 2017: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
https://www.readbyqxmd.com/read/27980856/effect-of-rpon-rpos-and-luxs-pathways-on-the-biofilm-formation-and-antibiotic-sensitivity-of-borrelia-burgdorferi
#4
Eva Sapi, Priyanka A S Theophilus, Truc V Pham, Divya Burugu, David F Luecke
Borrelia burgdorferi, the causative agent of Lyme disease, is capable of forming biofilm in vivo and in vitro, a structure well known for its resistance to antimicrobial agents. For the formation of biofilm, signaling processes are required to communicate with the surrounding environment such as it was shown for the RpoN-RpoS alternative sigma factor and for the LuxS quorum-sensing pathways. Therefore, in this study, the wild-type B. burgdorferi and different mutant strains lacking RpoN, RpoS, and LuxS genes were studied for their growth characteristic and development of biofilm structures and markers as well as for their antibiotic sensitivity...
December 1, 2016: European Journal of Microbiology & Immunology
https://www.readbyqxmd.com/read/27935141/evolution-of-a-multi-step-phosphorelay-signal-transduction-system-in-ensifer-recruitment-of-the-sigma-factor-rpon-and-a-novel-enhancer-binding-protein-triggers-acid-activated-gene-expression
#5
Rui Tian, Stephan Heiden, Wan A M Osman, Julie K Ardley, Euan K James, Margaret M Gollagher, Ravi Tiwari, Rekha Seshadri, Nikos C Kyrpides, Wayne G Reeve
Most Ensifer strains are comparatively acid sensitive, compromising their persistence in low pH soils. In the acid-tolerant strain Ensifer medicae WSM419, the acid-activated expression of lpiA is essential for enhancing survival in lethal acidic conditions. Here we characterise a multi-step phosphorelay signal transduction pathway consisting of TcsA, TcrA, FsrR, RpoN and its cognate enhancer-binding protein EbpA, which is required for the induction of lpiA and the downstream acvB gene. The fsrR, tcrA, tcsA and rpoN genes were constitutively expressed, whereas lpiA and acvB were strongly acid-induced...
December 9, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27864172/the-ebpa-rpon-regulatory-pathway-of-the-pathogen-leptospira-interrogans-is-essential-for-survival-in-the-environment
#6
Wei-Lin Hu, Christopher J Pappas, Jun-Jie Zhang, You-Yun Yang, Jie Yan, Mathieu Picardeau, X Frank Yang
Leptospira interrogans is the agent of leptospirosis, a reemerging zoonotic disease. It is transmitted to humans through environmental surface waters contaminated by the urine of mammals chronically infected by pathogenic strains able to survive in water for long periods. Little is known about the regulatory pathways underlying environmental sensing and host adaptation of L. interrogans during its enzootic cycle. This study identifies the EbpA-RpoN regulatory pathway in L. interrogans In this pathway, EbpA, a σ(54) activator and putative prokaryotic enhancer-binding protein (EBP), and the alternative sigma factor RpoN (σ(54)) control expression of at least three genes, encoding AmtB (an ammonium transport protein) and two proteins of unknown function...
February 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27817190/high-frequency-targeted-mutagenesis-in-pseudomonas-stutzeri-using-a-vector-free-allele-exchange-protocol
#7
Ahmed E Gomaa, Zhiping Deng, Zhimin Yang, Liguo Shang, Yuhua Zhan, Wei Lu, Min Lin, Yongliang Yan
The complexity of the bacterial recombination system is a barrier for the construction of bacterial mutants for the further functional investigation of specific genes. Several protocols have been developed to inactivate genes from the genus Pseudomonas. Those protocols are complicated and time-consuming and mostly do not enable easy construction of multiple knock-ins/outs. The current study describes a single and double crossover-recombination system using an optimized Vector-Free Allele Exchange (VFAE) protocol for gene disruption and gene replacement in a single species of the family Pseudomonadaceae...
November 4, 2016: Journal of Microbiology and Biotechnology
https://www.readbyqxmd.com/read/27777366/effect-of-crc-and-hfq-proteins-on-the-transcription-processing-and-stability-of-the-pseudomonas-putida-crcz-srna
#8
Sofía Hernández-Arranz, Dione Sánchez-Hevia, Fernando Rojo, Renata Moreno
In Pseudomonas putida, the Hfq and Crc proteins regulate the expression of many genes in response to nutritional and environmental cues, by binding to mRNAs that bear specific target motifs and inhibiting their translation. The effect of these two proteins is antagonized by the CrcZ and CrcY small RNAs (sRNAs), the levels of which vary greatly according to growth conditions. The crcZ and crcY genes are transcribed from promoters PcrcZ and PcrcY, respectively, a process that relies on the CbrB transcriptional activator and the RpoN σ factor...
December 2016: RNA
https://www.readbyqxmd.com/read/27701843/expression-of-the-diguanylate-cyclase-gcba-is-regulated-by-fleq-in-response-to-cyclic-di-gmp-in-pseudomonas-putida-kt2440
#9
Yujie Xiao, Hailing Nie, Huizhong Liu, Wenli Chen, Qiaoyun Huang
Cyclic di-GMP (c-di-GMP), a ubiquitous bacterial second messenger that regulates diverse cellular processes, is synthesized by diguanylate cyclase (DGC) and degraded by phosphodiesterase (PDE). GcbA is a well conserved DGC among Pseudomonas species, and has been reported to influence biofilm formation and flagellar motility in Pseudomonas fluorescens and Pseudomonas aeruginosa. Here we confirm the function of GcbA in Pseudomonas putida and reveal that expression of GcbA is regulated by FleQ in response to c-di-GMP...
October 4, 2016: Environmental Microbiology Reports
https://www.readbyqxmd.com/read/27629414/multiple-transcriptional-factors-regulate-transcription-of-the-rpoe-gene-in-escherichia-coli-under-different-growth-conditions-and-when-the-lipopolysaccharide-biosynthesis-is-defective
#10
Gracjana Klein, Anna Stupak, Daria Biernacka, Pawel Wojtkiewicz, Buko Lindner, Satish Raina
The RpoE σ factor is essential for the viability of Escherichia coli RpoE regulates extracytoplasmic functions including lipopolysaccharide (LPS) translocation and some of its non-stoichiometric modifications. Transcription of the rpoE gene is positively autoregulated by Eσ(E) and by unknown mechanisms that control the expression of its distally located promoter(s). Mapping of 5' ends of rpoE mRNA identified five new transcriptional initiation sites (P1 to P5) located distal to Eσ(E)-regulated promoter. These promoters are activated in response to unique signals...
October 28, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27628932/fine-tuning-of-amino-sugar-homeostasis-by-eiia-ntr-in-salmonella-typhimurium
#11
Woongjae Yoo, Hyunjin Yoon, Yeong-Jae Seok, Chang-Ro Lee, Hyung Ho Lee, Sangryeol Ryu
The nitrogen-metabolic phosphotransferase system, PTS(Ntr), consists of the enzymes I(Ntr), NPr and IIA(Ntr) that are encoded by ptsP, ptsO, and ptsN, respectively. Due to the proximity of ptsO and ptsN to rpoN, the PTS(Ntr) system has been postulated to be closely related with nitrogen metabolism. To define the correlation between PTS(Ntr) and nitrogen metabolism, we performed ligand fishing with EIIA(Ntr) as a bait and revealed that D-glucosamine-6-phosphate synthase (GlmS) directly interacted with EIIA(Ntr)...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27617010/nitrogen-fixation-and-molecular-oxygen-comparative-genomic-reconstruction-of-transcription-regulation-in-alphaproteobacteria
#12
Olga V Tsoy, Dmitry A Ravcheev, Jelena Čuklina, Mikhail S Gelfand
Biological nitrogen fixation plays a crucial role in the nitrogen cycle. An ability to fix atmospheric nitrogen, reducing it to ammonium, was described for multiple species of Bacteria and Archaea. The transcriptional regulatory network for nitrogen fixation was extensively studied in several representatives of the class Alphaproteobacteria. This regulatory network includes the activator of nitrogen fixation NifA, working in tandem with the alternative sigma-factor RpoN as well as oxygen-responsive regulatory systems, one-component regulators FnrN/FixK and two-component system FixLJ...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27583250/modulating-salmonella-typhimurium-s-response-to-a-changing-environment-through-bacterial-enhancer-binding-proteins-and-the-rpon-regulon
#13
REVIEW
Christine E Hartman, David J Samuels, Anna C Karls
Transcription sigma factors direct the selective binding of RNA polymerase holoenzyme (Eσ) to specific promoters. Two families of sigma factors determine promoter specificity, the σ(70) (RpoD) family and the σ(54) (RpoN) family. In transcription controlled by σ(54), the Eσ(54)-promoter closed complex requires ATP hydrolysis by an associated bacterial enhancer-binding protein (bEBP) for the transition to open complex and transcription initiation. Given the wide host range of Salmonella enterica serovar Typhimurium, it is an excellent model system for investigating the roles of RpoN and its bEBPs in modulating the lifestyle of bacteria...
2016: Frontiers in Molecular Biosciences
https://www.readbyqxmd.com/read/27529795/comparative-analysis-of-sigma-factors-rpos-flia-and-rpon-in-edwardsiella-tarda
#14
COMPARATIVE STUDY
ShanShan Song, Yuanyuan Xue, Enfu Liu, Keping Wang, Yuanxing Zhang, Haizhen Wu, Huizhan Zhang
Sigma factors are important regulators that bacteria employ to cope with environmental changes. Studies on the functions of sigma factors have uncovered their roles in many important cellular activities, such as growth, stress tolerance, motility, biofilm formation, and virulence. However, comparative analyses of sigma factors that examine their common and unique features or elucidate their cross-regulatory relationships have rarely been conducted for Edwardsiella tarda. Here, we characterized and compared motility and resistance to oxidative stress of E...
October 2016: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/27525653/two-different-virulence-related-regulatory-pathways-in-borrelia-burgdorferi-are-directly-affected-by-osmotic-fluxes-in-the-blood-meal-of-feeding-ixodes-ticks
#15
Sébastien Bontemps-Gallo, Kevin Lawrence, Frank C Gherardini
Lyme disease, caused by Borrelia burgdorferi, is a vector-borne illness that requires the bacteria to adapt to distinctly different environments in its tick vector and various mammalian hosts. Effective colonization (acquisition phase) of a tick requires the bacteria to adapt to tick midgut physiology. Successful transmission (transmission phase) to a mammal requires the bacteria to sense and respond to the midgut environmental cues and up-regulate key virulence factors before transmission to a new host. Data presented here suggest that one environmental signal that appears to affect both phases of the infective cycle is osmolarity...
August 2016: PLoS Pathogens
https://www.readbyqxmd.com/read/27431228/rpon-modulates-carbapenem-tolerance-in-pseudomonas-aeruginosa-through-pseudomonas-quinolone-signal-and-pqse
#16
Darija Viducic, Keiji Murakami, Takashi Amoh, Tsuneko Ono, Yoichiro Miyake
The ability of Pseudomonas aeruginosa to rapidly modulate its response to antibiotic stress and persist in the presence of antibiotics is closely associated with the process of cell-to-cell signaling. The alternative sigma factor RpoN (σ(54)) is involved in the regulation of quorum sensing (QS) and plays an important role in the survival of stationary-phase cells in the presence of carbapenems. Here, we demonstrate that a ΔrpoN mutant grown in nutrient-rich medium has increased expression of pqsA, pqsH, and pqsR throughout growth, resulting in the increased production of the Pseudomonas quinolone signal (PQS)...
October 2016: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/27407147/the-novel-regulatory-ncrna-nfis-optimizes-nitrogen-fixation-via-base-pairing-with-the-nitrogenase-gene-nifk-mrna-in-pseudomonas-stutzeri-a1501
#17
Yuhua Zhan, Yongliang Yan, Zhiping Deng, Ming Chen, Wei Lu, Chao Lu, Liguo Shang, Zhimin Yang, Wei Zhang, Wei Wang, Yun Li, Qi Ke, Jiasi Lu, Yuquan Xu, Liwen Zhang, Zhihong Xie, Qi Cheng, Claudine Elmerich, Min Lin
Unlike most Pseudomonas, the root-associated bacterium Pseudomonas stutzeri A1501 fixes nitrogen after the horizontal acquisition of a nitrogen-fixing (nif) island. A genome-wide search for small noncoding RNAs (ncRNAs) in P. stutzeri A1501 identified the novel P. stutzeri-specific ncRNA NfiS in the core genome, whose synthesis was significantly induced under nitrogen fixation or sorbitol stress conditions. The expression of NfiS was RNA chaperone Hfq-dependent and activated by the sigma factor RpoN/global nitrogen activator NtrC/nif-specific activator NifA regulatory cascade...
July 26, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27325678/ethanolamine-catabolism-in-pseudomonas-aeruginosa-pao1-is-regulated-by-the-enhancer-binding-protein-eatr-pa4021-and-the-alternative-sigma-factor-rpon
#18
Benjamin R Lundgren, Zaara Sarwar, Atahualpa Pinto, Jack G Ganley, Christopher T Nomura
UNLABELLED: Although genes encoding enzymes and proteins related to ethanolamine catabolism are widely distributed in the genomes of Pseudomonas spp., ethanolamine catabolism has received little attention among this metabolically versatile group of bacteria. In an attempt to shed light on this subject, this study focused on defining the key regulatory factors that govern the expression of the central ethanolamine catabolic pathway in Pseudomonas aeruginosa PAO1. This pathway is encoded by the PA4022-eat-eutBC operon and consists of a transport protein (Eat), an ethanolamine-ammonia lyase (EutBC), and an acetaldehyde dehydrogenase (PA4022)...
September 1, 2016: Journal of Bacteriology
https://www.readbyqxmd.com/read/27230588/epistatic-interactions-between-ancestral-genotype-and-beneficial-mutations-shape-evolvability-in-pseudomonas-aeruginosa
#19
Danna R Gifford, Macarena Toll-Riera, R Craig MacLean
The idea that interactions between mutations influence adaptation by driving populations to low and high fitness peaks on adaptive landscapes is deeply ingrained in evolutionary theory. Here, we investigate the impact of epistasis on evolvability by challenging populations of two Pseudomonas aeruginosa clones bearing different initial mutations (in rpoB conferring rifampicin resistance, and the type IV pili gene network) to adaptation to a medium containing l-serine as the sole carbon source. Despite being initially indistinguishable in fitness, populations founded by the two ancestral genotypes reached different fitness following 300 generations of evolution...
July 2016: Evolution; International Journal of Organic Evolution
https://www.readbyqxmd.com/read/26977110/insight-into-the-dual-functions-of-bacterial-enhancer-binding-protein-rrp2-of-borrelia-burgdorferi
#20
Yanping Yin, Youyun Yang, Xuwu Xiang, Qian Wang, Zhang-Nv Yang, Jon Blevins, Yongliang Lou, X Frank Yang
UNLABELLED: It is well established that the RpoN-RpoS sigma factor (σ(54)-σ(S)) cascade plays an essential role in differential gene expression during the enzootic cycle of Borrelia burgdorferi, the causative agent of Lyme disease. The RpoN-RpoS pathway is activated by the response regulator/σ(54)-dependent activator (also called bacterial enhancer-binding protein [bEBP]) Rrp2. One unique feature of Rrp2 is that this activator is essential for cell replication, whereas RpoN-RpoS is dispensable for bacterial growth...
May 15, 2016: Journal of Bacteriology
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