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https://www.readbyqxmd.com/read/28500044/rpon-%C3%AF-54-is-required-for-floc-formation-but-not-for-extracellular-polysaccharide-biosynthesis-in-a-floc-forming-aquincola-tertiaricarbonis-strain
#1
Dianzhen Yu, Ming Xia, Liping Zhang, Yulong Song, You Duan, Tong Yuan, Minjie Yao, Liyou Wu, Chunyuan Tian, Zhenbin Wu, Xiangzhen Li, Jizhong Zhou, Dongru Qiu
Some bacteria are capable of forming flocs in which bacterial cells are self-flocculated by secreted extracellular polysaccharides and other biopolymers. The floc-forming bacteria play a central role in activated sludge, which has been widely utilized for the treatment of municipal sewage and industrial wastewater. Here we use a floc-forming bacterium, Aquincola tertiaricarbonis RN12, as a model to explore the biosynthesis of EPS and the regulation of floc-formation. A large gene cluster for exopolysaccharide biosynthesis and a gene encoding the alternative sigma factor RpoN1, one of the four paralogues, have been identified in the floc-formation-deficient mutants generated by transposon mutagenesis and the gene functions have been further confirmed by genetic complementation analyses...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28497290/medium-chain-length-polyhydroxyalkanoates-synthesis-by-pseudomonas-putida-kt2440-rela-spot-mutant-bioprocess-characterization-and-transcriptome-analysis
#2
Justyna Mozejko-Ciesielska, Dorota Dabrowska, Agnieszka Szalewska-Palasz, Slawomir Ciesielski
Pseudomonas putida KT2440 is a model bacteria used commonly for medium-chain-length polyhydroxyalkanoates (mcl-PHAs) production using various substrates. However, despite many studies conducted on P. putida KT2440 strain, the molecular mechanisms of leading to mcl-PHAs synthesis in reaction to environmental stimuli are still not clear. The rearrangement of the metabolism in response to environmental stress could be controlled by stringent response that modulates the transcription of many genes in order to promote survival under nutritional deprivation conditions...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28473604/recurrent-painful-ophthalmoplegic-neuropathy
#3
Cleo Huang, Maria Amasanti, Ben Lovell, Tim Young
Recurrent painful ophthalmologic neuropathy (RPON), previously termed ophthalmoplegic migraine, is characterised by repeated attacks of one or more ocular cranial nerve palsies with ipsilateral headache. Its cause remains unclear; it is currently thought to be neuropathic in origin, but there is debate in the literature. In documented cases, a third cranial nerve palsy is by far the most common. Here we present a case of RPON involveing the fourth and sixth cranial nervesonly. Thorough investigation, including MR scan of brain and lumbar puncture, found no alternative explanation...
May 4, 2017: Practical Neurology
https://www.readbyqxmd.com/read/28439037/regulation-of-a-glycerol-induced-quinoprotein-alcohol-dehydrogenase-by-%C3%AF-54-and-a-luxr-type-regulator-in-azospirillum-brasilense-sp7
#4
Vijay Shankar Singh, Ashutosh Prakash Dubey, Ankush Gupta, Sudhir Singh, Bhupendra Narain Singh, Anil Kumar Tripathi
Azospirillum brasilense Sp7 uses glycerol as carbon source for growth and nitrogen fixation. When grown in medium containing glycerol as carbon source it upregulates the expression of a protein which was identified as quinoprotein alcohol dehydrogenase (ExaA). Inactivation of exaA adversely affects the growth of A. brasilense on glycerol. Determination of the transcription start site of exaA revealed an RpoN dependent -12/-24 promoter consensus. The expression of an exaA:lacZ fusion was induced maximally by glycerol, and was dependent on σ(54) Bioinformatic analysis of the sequence flanking the -12/-24 promoter revealed a 17 bp sequence motif with a dyad symmetry of 6 nucleotides upstream of the promoter, disruption of which caused a drastic reduction in promoter activity...
April 24, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28419759/regulation-of-burkholderia%C3%A2-cenocepacia-biofilm-formation-by-rpon-and-the-c-di-gmp-effector-berb
#5
Mustafa Fazli, Morten Rybtke, Elisabeth Steiner, Elisabeth Weidel, Jens Berthelsen, Julie Groizeleau, Wu Bin, Boo Zhao Zhi, Zhang Yaming, Volkhard Kaever, Michael Givskov, Rolf W Hartmann, Leo Eberl, Tim Tolker-Nielsen
Knowledge about the molecular mechanisms that are involved in the regulation of biofilm formation is essential for the development of biofilm-control measures. It is well established that the nucleotide second messenger cyclic diguanosine monophosphate (c-di-GMP) is a positive regulator of biofilm formation in many bacteria, but more knowledge about c-di-GMP effectors is needed. We provide evidence that c-di-GMP, the alternative sigma factor RpoN (σ54), and the enhancer-binding protein BerB play a role in biofilm formation of Burkholderia cenocepacia by regulating the production of a biofilm-stabilizing exopolysaccharide...
April 16, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28412516/switching-between-nitrogen-and-glucose-limitation-unraveling-transcriptional-dynamics-in-escherichia-coli
#6
Michael Löffler, Joana Danica Simen, Jan Müller, Günter Jäger, Salaheddine Laghrami, Karin Schäferhoff, Andreas Freund, Ralf Takors, Ralf Takors
Transcriptional control under nitrogen and carbon-limitation conditions have been well analyzed for Escherichia coli. However, the transcriptional dynamics that underlie the shift in regulatory programs from nitrogen to carbon limitation is not well studied. In the present study, cells were cultivated at steady state under nitrogen (ammonia)-limited conditions then shifted to carbon (glucose) limitation to monitor changes in transcriptional dynamics. Nitrogen limitation was found to be dominated by sigma 54 (RpoN) and sigma 38 (RpoS), whereas the "housekeeping" sigma factor 70 (RpoD) and sigma 38 regulate cellular status under glucose limitation...
April 12, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28400753/the-helicobacter-pylori-j99-jhp0106-gene-under-the-control-of-the-csra-rpon-regulatory-system-modulates-flagella-formation-and-motility
#7
Cheng-Yen Kao, Jenn-Wei Chen, Shuying Wang, Bor-Shyang Sheu, Jiunn-Jong Wu
CsrA has been shown to positively control the expression of flagella-related genes, including flaA and flaB, through regulating expression of an alternative sigma factor RpoN in Helicobacter pylori J99. Here, we aimed to characterize the CsrA regulatory system by comparative transcriptomic analysis carried out with RNA-seq on strain J99 and a csrA mutant. Fifty-three genes in the csrA mutant were found to be differentially expressed compared with the wild-type. Among CsrA-regulated genes, jhp0106, with unclear function, was found located downstream of flaB in the J99 genome...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28373272/novel-dna-binding-and-regulatory-activities-for-%C3%AF-54-rpon-in-salmonella-typhimurium-14028s
#8
Ashley C Bono, Christine E Hartman, Sina Solaimanpour, Hao Tong, Steffen Porwollik, Michael McClelland, Jonathan G Frye, Jan Mrázek, Anna C Karls
The variable sigma (σ) subunit of the bacterial RNA polymerase (RNAP) holoenzyme, which is responsible for promoter specificity and open complex formation, plays a strategic role in the response to environmental changes. S Typhimurium utilizes the housekeeping σ(70) and five alternative sigma factors, including σ(54) The σ(54)-RNAP differs from other σ-RNAP holoenzymes in that it forms a stable closed complex with the promoter and requires ATP hydrolysis by an activated cognate bacterial enhancer binding protein (bEBP) to transition to open complex and initiate transcription...
April 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28270808/transcriptional-control-of-dual-transporters-involved-in-%C3%AE-ketoglutarate-utilization-reveals-their-distinct-roles-in-uropathogenic-escherichia-coli
#9
Wentong Cai, Xuwang Cai, Yongwu Yang, Shigan Yan, Haibin Zhang
Uropathogenic Escherichia coli (UPEC) are the primary causative agents of urinary tract infections. Some UPEC isolates are able to infect renal proximal tubule cells, and can potentially cause pyelonephritis. We have previously shown that to fulfill their physiological roles renal proximal tubule cells accumulate high concentrations of α-ketoglutarate (KG) and that gene cluster c5032-c5039 contribute to anaerobic utilization of KG by UPEC str. CFT073, thereby promoting its in vivo fitness. Given the importance of utilizing KG for UPEC, this study is designed to investigate the roles of two transporters KgtP and C5038 in KG utilization, their transcriptional regulation, and their contributions to UPEC fitness in vivo...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28177291/expression-of-flagellin-and-key-regulatory-flagellar-genes-in-the-non-motile-bacterium-piscirickettsia-salmonis
#10
Gabriela P Carril, Fernando A Gómez, Sergio H Marshall
The Piscirickettsia salmonis genome was screened to evaluate potential flagella-related open reading frames, as well as their genomic organization and eventual expression. A complete and organized set of flagellar genes was found for P. salmonis, although no structural flagellum has ever been reported for this bacterium. To gain further understanding, the hierarchical flagellar cascade described for Legionella pneumophila was used as a reference model for putative analysis in P. salmonis. Specifically, 5 of the most relevant genes from this cascade were chosen, including 3 regulatory genes (fleQ, triggers the cascade; fliA, regulates the σ28-coding gene; and rpoN, an RNA polymerase-dependent gene) and 2 terminal structural genes (flaA and flaB, flagellin and a flagellin-like protein, respectively)...
February 8, 2017: Diseases of Aquatic Organisms
https://www.readbyqxmd.com/read/28167521/ddar-pa1196-regulates-expression-of-dimethylarginine-dimethylaminohydrolase-for-the-metabolism-of-methylarginines-in-pseudomonas-aeruginosa-pao1
#11
Benjamin R Lundgren, Frank J Bailey, Gabriella Moley, Christopher T Nomura
Dimethylarginine dimethylaminohydrolases (DDAHs) catalyze the hydrolysis of methylarginines to yield l-citrulline and methylamines as products. DDAHs and their central roles in methylarginine metabolism have been characterized for eukaryotic cells. While DDAHs are known to exist in some bacteria, including Streptomyces coelicolor and Pseudomonas aeruginosa, the physiological importance and genetic regulation of bacterial DDAHs remain poorly understood. To provide some insight into bacterial methylarginine metabolism, this study focused on identifying the key elements or factors regulating DDAH expression in P...
April 15, 2017: Journal of Bacteriology
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
#12
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...
April 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28040562/enzootic-origins-for-clinical-manifestations-of-lyme-borreliosis
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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 protocol for gene disruption and gene replacement in a single species of the family Pseudomonadaceae...
February 28, 2017: 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
#19
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
#20
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
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