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https://www.readbyqxmd.com/read/28891458/ppgpp-and-cytotoxicity-diversity-in-shiga-toxin-producing-escherichia-coli-stec-isolates-corrigendum
#1
A E Stella, D Luz, R M F Piazza, B Spira
No abstract text is available yet for this article.
September 11, 2017: Epidemiology and Infection
https://www.readbyqxmd.com/read/28887466/hplc-based-quantification-of-bacterial-housekeeping-nucleotides-and-alarmone-messengers-ppgpp-and-pppgpp
#2
Vallo Varik, Sofia Raquel Alves Oliveira, Vasili Hauryliuk, Tanel Tenson
Here we describe an HPLC-based method to quantify bacterial housekeeping nucleotides and the signaling messengers ppGpp and pppGpp. We have replicated and tested several previously reported HPLC-based approaches and assembled a method that can process 50 samples in three days, thus making kinetically resolved experiments feasible. The method combines cell harvesting by rapid filtration, followed by acid extraction, freeze-drying with chromatographic separation. We use a combination of C18 IPRP-HPLC (GMP unresolved and co-migrating with IMP; GDP and GTP; AMP, ADP and ATP; CTP; UTP) and SAX-HPLC in isocratic mode (ppGpp and pppGpp) with UV detection...
September 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28871248/identification-and-functional-characterization-of-small-alarmone-synthetases-in-corynebacterium-glutamicum
#3
Matthias Ruwe, Jörn Kalinowski, Marcus Persicke
The hyperphosphorylated guanosine derivatives ppGpp and pppGpp represent global regulators of the bacterial stress response, as they act as central elements of the stringent response system. Although it was assumed that both, (p)ppGpp synthesis and hydrolysis, are catalyzed by one bifunctional RSH-protein in the actinobacterial model organism Corynebacterium glutamicum ATCC 13032, two putative short alarmone synthetases (SASs) were identified by bioinformatic analyses. The predicted sequences of both enzymes, designated as RelP(*)Cg and RelSCg, exhibit high similarities to the conserved (p)ppGpp synthetase catalytic domain...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28870288/influence-of-p-ppgpp-on-biofilm-regulation-in-pseudomonas-putida-kt2440
#4
Huizhong Liu, Yujie Xiao, Hailing Nie, Qiaoyun Huang, Wenli Chen
The global regulatory molecule (p)ppGpp is synthesized under limited nutrition conditions and involves in many cellular processes in bacteria. (p)ppGpp has been reported to affect biofilm formation in several bacterial species. Here, we found that deletion of (p)ppGpp synthase genes of Pseudomonas putida KT2440 led to enhanced biofilm formation in polystyrene microtitre plates. Besides, the pellicle of this mutant formed at the air-liquid interface lost the robust structure and became frail. The biofilm formation and its structure are mainly determined by exopolysaccharides (EPSs) and adhesins...
November 2017: Microbiological Research
https://www.readbyqxmd.com/read/28864445/dissection-of-the-molecular-circuitry-controlling-virulence-in-francisella-tularensis
#5
Bonnie J Cuthbert, Wilma Ross, Amy E Rohlfing, Simon L Dove, Richard L Gourse, Richard G Brennan, Maria A Schumacher
Francisella tularensis, the etiological agent of tularemia, is one of the most infectious bacteria known. Because of its extreme pathogenicity, F. tularensis is classified as a category A bioweapon by the US government. F. tularensis virulence stems from genes encoded on the Francisella pathogenicity island (FPI). An unusual set of Francisella regulators-the heteromeric macrophage growth locus protein A (MglA)-stringent starvation protein A (SspA) complex and the DNA-binding protein pathogenicity island gene regulator (PigR)-activates FPI transcription and thus is essential for virulence...
September 1, 2017: Genes & Development
https://www.readbyqxmd.com/read/28854732/synchronized-switching-of-multiple-toxin-antitoxin-modules-by-p-ppgpp-fluctuation
#6
Chengzhe Tian, Szabolcs Semsey, Namiko Mitarai
Toxin-antitoxin (TA) loci are widespread in bacteria including important pathogenic species. Recent studies suggest that TA systems play a key role in persister formation. However, the persistence phenotype shows only weak dependence on the number of TA systems, i.e. they are functionally redundant. We use a mathematical model to investigate the interaction of multiple TA systems in the switching between growth and persistence. We explore two scenarios: (i) TA systems are bistable and each TA system experiences its own noise and (ii) the noise in the level of common stress signal (e...
August 21, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28836724/sleeper-cells-the-stringent-response-and-persistence-in-the-borreliella-borrelia-burgdorferi-enzootic-cycle
#7
REVIEW
Felipe C Cabello, Henry P Godfrey, Julia V Bugrysheva, Stuart A Newman
Infections with tick-transmitted Borreliella (Borrelia) burgdorferi, the cause of Lyme disease, represent an increasingly large public health problem in North America and Europe. The ability of these spirochetes to maintain themselves for extended periods of time in their tick vectors and vertebrate reservoirs is crucial for continuance of the enzootic cycle as well as for the increasing exposure of humans to them. The stringent response mediated by the alarmone (p)ppGpp has been determined to be a master regulator in B...
August 24, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28820325/small-alarmone-synthetases-as-novel-bacterial-rna-binding-proteins
#8
Vasili Hauryliuk, Gemma C Atkinson
The alarmone nucleotides guanosine pentaphosphate (pppGpp) and tetraphosphate (ppGpp), collectively referred to as (p)ppGpp, are key regulators of bacterial growth, stress adaptation, antibiotic tolerance and pathogenicity. We have recently shown that the Small Alarmone Synthetase (SAS) RelQ from the Gram-positive pathogen Enterococcus faecalis has an RNA-binding activity (Beljantseva et al. 2017). RelQ's activities as an enzyme and as a RNA-binding protein are mutually incompatible: binding of single-stranded RNA potently inhibits (p)ppGpp synthesis in a sequence-specific manner, and RelQ's enzymatic activity destabilizes the RNA:RelQ complex...
August 18, 2017: RNA Biology
https://www.readbyqxmd.com/read/28750057/bactericidal-activity-of-alpha-bromocinnamaldehyde-against-persisters-in-escherichia-coli
#9
Qingshan Shen, Wei Zhou, Liangbin Hu, Yonghua Qi, Hongmei Ning, Jian Chen, Haizhen Mo
Persisters are tolerant to multiple antibiotics, and widely distributed in bacteria, fungi, parasites, and even cancerous human cell populations, leading to recurrent infections and relapse after therapy. In this study, we investigated the potential of cinnamaldehyde and its derivatives to eradicate persisters in Escherichia coli. The results showed that 200 μg/ml of alpha-bromocinnamaldehyde (Br-CA) was capable of killing all E. coli cells during the exponential phase. Considering the heterogeneous nature of persisters, multiple types of persisters were induced and exposed to Br-CA...
2017: PloS One
https://www.readbyqxmd.com/read/28743817/bacterial-signaling-nucleotides-inhibit-yeast-cell-growth-by-impacting-mitochondrial-and-other-specifically-eukaryotic-functions
#10
Andy Hesketh, Marta Vergnano, Chris Wan, Stephen G Oliver
We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP...
July 25, 2017: MBio
https://www.readbyqxmd.com/read/28678862/pseudomonas-aeruginosa-cells-attached-to-a-surface-display-a-typical-proteome-early-as-20-minutes-of-incubation
#11
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/28652326/trar-directly-regulates-transcription-initiation-by-mimicking-the-combined-effects-of-the-global-regulators-dksa-and-ppgpp
#12
Saumya Gopalkrishnan, Wilma Ross, Albert Y Chen, Richard L Gourse
The Escherichia coli F element-encoded protein TraR is a distant homolog of the chromosome-encoded transcription factor DksA. Here we address the mechanism by which TraR acts as a global regulator, inhibiting some promoters and activating others. We show that TraR regulates transcription directly in vitro by binding to the secondary channel of RNA polymerase (RNAP) using interactions similar, but not identical, to those of DksA. Even though it binds to RNAP with only slightly higher affinity than DksA and is only half the size of DksA, TraR by itself inhibits transcription as strongly as DksA and ppGpp combined and much more than DksA alone...
July 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28633201/rapid-start-up-of-denitrifying-granular-sludge-by-dosing-with-semi-starvation-fluctuation-c-n-ratio-strategy
#13
Wenyu Niu, Jianbo Guo, Jing Lian, Yuanyuan Song, Caicai Lu, Haibo Li, Yi Han, Pengna Yin
This study cultivated denitrifying granular sludge in three UASB reactors by the semi-starvation fluctuation C/N ratio strategy (reactor 1 (R1): constant C/N ratio; R2: regular fluctuation C/N ratio; and R3: semi-starvation fluctuation C/N ratio (SSF)). Microbial aggregates appeared in R1, R2 and R3 on days 28, 14 and 6, respectively. Compared with the results in R1 and R2, the guanosine tetraphosphate (ppGpp) concentration was highest, the acyl homoserine lactones (AHLs) concentration quickly reached a certain threshold, and more protein (PN) of extracellular polymeric substances (EPS) secretion resulted in the rapid formation of denitrifying granular sludge in R3...
October 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28624614/gene-transfer-agent-promotes-evolvability-within-the-fittest-subpopulation-of-a-bacterial-pathogen
#14
Maxime Québatte, Matthias Christen, Alexander Harms, Jonas Körner, Beat Christen, Christoph Dehio
The Bartonella gene transfer agent (BaGTA) is an archetypical example for domestication of a phage-derived element to permit high-frequency genetic exchange in bacterial populations. Here we used multiplexed transposon sequencing (TnSeq) and single-cell reporters to globally define the core components and transfer dynamics of BaGTA. Our systems-level analysis has identified inner- and outer-circle components of the BaGTA system, including 55 regulatory components, as well as an additional 74 and 107 components mediating donor transfer and recipient uptake functions...
June 28, 2017: Cell Systems
https://www.readbyqxmd.com/read/28611182/the-lost-language-of-the-rna-world
#15
REVIEW
James W Nelson, Ronald R Breaker
The possibility of an RNA World is based on the notion that life on Earth passed through a primitive phase without proteins, a time when all genomes and enzymes were composed of ribonucleic acids. Numerous apparent vestiges of this ancient RNA World remain today, including many nucleotide-derived coenzymes, self-processing ribozymes, metabolite-binding riboswitches, and even ribosomes. Many of the most common signaling molecules and second messengers used by modern organisms are also formed from RNA nucleotides or their precursors...
June 13, 2017: Science Signaling
https://www.readbyqxmd.com/read/28602657/fatty-acid-availability-sets-cell-envelope-capacity-and-dictates-microbial-cell-size
#16
Stephen Vadia, Jessica L Tse, Rafael Lucena, Zhizhou Yang, Douglas R Kellogg, Jue D Wang, Petra Anne Levin
Nutrients-and by extension biosynthetic capacity-positively impact cell size in organisms throughout the tree of life. In bacteria, cell size is reduced 3-fold in response to nutrient starvation or accumulation of the alarmone ppGpp, a global inhibitor of biosynthesis. However, whether biosynthetic capacity as a whole determines cell size or whether particular anabolic pathways are more important than others remains an open question. Here we identify fatty acid synthesis as the primary biosynthetic determinant of Escherichia coli size and present evidence supporting a similar role for fatty acids as a positive determinant of size in the Gram-positive bacterium Bacillus subtilis and the single-celled eukaryote Saccharomyces cerevisiae...
June 19, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28597815/dksa-hapr-rpos-axis-regulates-haemagglutinin-protease-production-in-vibrio-cholerae
#17
Pallabi Basu, Ritesh Ranjan Pal, Shreya Dasgupta, Rupak K Bhadra
DksA acts as a co-factor for the intracellular small signalling molecule ppGpp during the stringent response. We recently reported that the expression of the haemagglutinin protease (HAP), which is needed for shedding of the cholera pathogen Vibrio cholerae during the late phase of infection, is significantly downregulated in V. cholerae ∆dksA mutant (∆dksAVc) cells. So far, it has been shown that HAP production by V. cholerae cells is critically regulated by HapR and also by RpoS. Here, we provide evidence that V...
June 8, 2017: Microbiology
https://www.readbyqxmd.com/read/28587697/ppgpp-and-cytotoxicity-diversity-in-shiga-toxin-producing-escherichia-coli-stec-isolates
#18
A E Stella, D Luz Hessel DA Cunha, R M F Piazza, B Spira
Shiga toxin-producing Escherichia coli (STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across the E...
August 2017: Epidemiology and Infection
https://www.readbyqxmd.com/read/28575317/ribosomal-selection-of-mrnas-with-degenerate-initiation-triplets
#19
He Chengguang, Paola Sabatini, Letizia Brandi, Anna M Giuliodori, Cynthia L Pon, Claudio O Gualerzi
To assess the influence of degenerate initiation triplets on mRNA recruitment by ribosomes, five mRNAs identical but for their start codon (AUG, GUG, UUG, AUU and AUA) were offered to a limiting amount of ribosomes, alone or in competition with an identical AUGmRNA bearing a mutation conferring different electrophoretic mobility to the product. Translational efficiency and competitiveness of test mRNAs toward this AUGmRNA were determined quantifying the relative amounts of the electrophoretically separated wt and mutated products synthesized in vitro and found to be influenced to different extents by the nature of their initiation triplet and by parameters such as temperature and nutrient availability in the medium...
July 7, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28536785/significance-of-accumulation-of-the-alarmone-p-ppgpp-in-chloroplasts-for-controlling-photosynthesis-and-metabolite-balance-during-nitrogen-starvation-in-arabidopsis
#20
Rina Honoki, Sumire Ono, Akira Oikawa, Kazuki Saito, Shinji Masuda
The regulatory nucleotides, guanosine 5'-triphosphate 3'-diphosphate (pppGpp) and guanosine 5'-diphosphate 3'-diphosphate (ppGpp), were originally identified in Escherichia coli, and control a large set of gene expression and enzyme activities. The (p)ppGpp-dependent control of cell activities is referred to as the stringent response. A growing number of (p)ppGpp synthase/hydrolase homologs have been identified in plants, which are localized in plastids in Arabidopsis thaliana. We recently reported that the Arabidopsis mutant overproducing ppGpp in plastids showed dwarf chloroplasts, and transcript levels in the mutant plastids were significantly suppressed...
May 23, 2017: Photosynthesis Research
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