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Bacteria AND essential genes

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https://www.readbyqxmd.com/read/29343515/discovery-of-genes-required-for-lipoteichoic-acid-glycosylation-predicts-two-distinct-mechanism-for-wall-teichoic-acid-glycosylation
#1
Jeanine Rismondo, Matthew G Percy, Angelika Gründling
The bacterial cell wall is an important and highly complex structure that is essential for bacterial growth because it protects bacteria from cell lysis and environmental insults. A typical Gram-positive bacterial cell wall is composed of peptidoglycan and the secondary cell wall polymers, wall teichoic acid (WTA) and lipoteichoic acid (LTA). In many Gram-positive bacteria, LTA is a polyglycerol-phosphate chain that is decorated with D-alanine and sugar residues. However, the function of and proteins responsible for the glycosylation of LTA are either unknown or not well-characterized...
January 17, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29339611/mechanism-of-1-4-dioxane-microbial-degradation-revealed-by-16s-rrna-and-metatranscriptomic-analyses
#2
Xiangyu Guan, Fei Liu, Jing Wang, Caoxiang Li, Xiaoxuan Zheng
1,4-Dioxane (dioxane), a probable human carcinogen, often exists in industrial wastewater and domestic sewage. In this study, we applied 16S rRNA and metatranscriptomic methods to analyze the dioxane biodegradation mechanism by activated sludge. Tetrahydrofuran (THF) was added as an essential co-metabolite to promote the degradation of dioxane. We found the dioxane removal ratio increased with increasing THF concentrations. When the THF concentration increased from 60.0 to 200.0 mg/L, the dioxane degradation rate was stable...
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29339415/genome-wide-identification-by-transposon-insertion-sequencing-of-escherichia-coli-k1-genes-essential-for-in-vitro-growth-gastrointestinal-colonizing-capacity-and-survival-in-serum
#3
Alex J McCarthy, Richard A Stabler, Peter W Taylor
Escherichia coli K1 strains are major causative agents of invasive disease of the new born. The age dependency of infection can be reproduced in the neonatal rat. Colonization of the small intestine following oral administration of K1 bacteria leads rapidly to invasion of the blood circulation; bacteria that avoid capture by the mesenteric lymphatic system and evade antibacterial mechanisms in the blood may disseminate to cause organ-specific infections such as meningitis. Some E. coli K1 surface constituents, in particular the polysialic acid capsule, are known to contribute to invasive potential but a comprehensive picture of the factors that determine the fully virulent phenotype has not so far emerged...
January 16, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29331510/effects-of-sub-minimum-inhibitory-concentrations-of-lemon-essential-oil-on-the-acid-tolerance-and-biofilm-formation-of-streptococcus-mutans
#4
Yanwei Sun, Sijia Chen, Chen Zhang, Yali Liu, Li Ma, Xiangyu Zhang
OBJECTIVES: Lemon essential oil (LEO) is a kind of secondary metabolite from lemon peels and has been found to inhibit cariogenic bacteria for decades. However, its effects on main cariogenic virulence factors are rarely reported. The present study aimed to investigate the effects of sub-minimum inhibitory concentrations (sub-MICs) of LEO on the acid tolerance and biofilm formation of Streptococcus mutans (S. mutans) and preliminarily reveal the possible underlying mechanisms. DESIGNS: Effects of LEO on the acid tolerance and biofilm formation of S...
December 29, 2017: Archives of Oral Biology
https://www.readbyqxmd.com/read/29327330/microbiome-analysis-and-omics-studies-of-microbial-denitrification-processes-in-wastewater-treatment-recent-advances
#5
REVIEW
Lili Miao, Zhipei Liu
Nitrogen pollution is an increasingly severe worldwide problem because of drainage of nitrogen-containing wastewater and intensive application of nitrogen-containing fertilizers. Denitrification, a key process in nitrogen cycles, is commonly employed for nitrogen removal in engineered wastewater treatment systems. Biological denitrification is performed by denitrifying microbes (bacteria) that use nitrate as terminal electron acceptor. Better understanding the functions of diverse microbial populations in denitrification-based wastewater treatment systems, and the interactions of these populations with operating environments, is essential for improving both treatment performance and system stability...
January 9, 2018: Science China. Life Sciences
https://www.readbyqxmd.com/read/29324800/hepcidin-deficiency-and-iron-deficiency-do-not-alter-tuberculosis-susceptibility-in-a-murine-m-tb-infection-model
#6
Rachel Harrington-Kandt, Elena Stylianou, Lucy A Eddowes, Pei Jin Lim, Lisa Stockdale, Nawamin Pinpathomrat, Naomi Bull, Janet Pasricha, Marta Ulaszewska, Yulia Beglov, Sophie Vaulont, Hal Drakesmith, Helen McShane
Tuberculosis (TB), caused by the macrophage-tropic pathogen Mycobacterium tuberculosis (M.tb) is a highly prevalent infectious disease. Since an immune correlate of protection or effective vaccine have yet to be found, continued research into host-pathogen interactions is important. Previous literature reports links between host iron status and disease outcome for many infections, including TB. For some extracellular bacteria, the iron regulatory hormone hepcidin is essential for protection against infection...
2018: PloS One
https://www.readbyqxmd.com/read/29324231/decoding-a-salmonella-typhi-regulatory-network-that-controls-typhoid-toxin-expression-within-human-cells
#7
Casey C Fowler, Jorge E Galán
Salmonella Typhi is the cause of typhoid fever, a major global health concern. An essential virulence factor of this pathogen is typhoid toxin. In contrast to most AB-type toxins, typhoid toxin is exclusively expressed by intracellular bacteria. The regulatory networks that ensure this unique gene expression pattern are unknown. Here, we developed FAST-INSeq, a genome-wide screening approach to identify S. Typhi genes required for typhoid toxin expression within infected cells. We find that typhoid toxin expression is controlled by a silencing and counter-silencing mechanism through the opposing actions of the PhoP/PhoQ two-component regulatory system and the histone-like protein H-NS...
January 10, 2018: Cell Host & Microbe
https://www.readbyqxmd.com/read/29323132/assembly-of-an-atypical-%C3%AE-macroglobulin-complex-from-pseudomonas-aeruginosa
#8
Samira Zouhir, Mylène Robert-Genthon, Daniel Maragno Trindade, Viviana Job, Marko Nedeljković, Cécile Breyton, Christine Ebel, Ina Attrée, Andréa Dessen
Alpha-2-macroglobulins (A2Ms) are large spectrum protease inhibitors that are major components of the eukaryotic immune system. Pathogenic and colonizing bacteria, such as the opportunistic pathogen Pseudomonas aeruginosa, also carry structural homologs of eukaryotic A2Ms. Two types of bacterial A2Ms have been identified: Type I, much like the eukaryotic form, displays a conserved thioester that is essential for protease targeting, and Type II, which lacks the thioester and to date has been poorly studied despite its ubiquitous presence in Gram-negatives...
January 11, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29316921/insights-into-metabolic-osmoadaptation-of-the-ectoines-producer-bacterium-chromohalobacter-salexigens-through-a-high-quality-genome-scale-metabolic-model
#9
Francine Piubeli, Manuel Salvador, Montserrat Argandoña, Joaquín J Nieto, Vicente Bernal, Jose M Pastor, Manuel Cánovas, Carmen Vargas
BACKGROUND: The halophilic bacterium Chromohalobacter salexigens is a natural producer of ectoines, compatible solutes with current and potential biotechnological applications. As production of ectoines is an osmoregulated process that draws away TCA intermediates, bacterial metabolism needs to be adapted to cope with salinity changes. To explore and use C. salexigens as cell factory for ectoine(s) production, a comprehensive knowledge at the systems level of its metabolism is essential...
January 9, 2018: Microbial Cell Factories
https://www.readbyqxmd.com/read/29314657/molecular-and-genetic-interactions-of-the-rna-degradation-machineries-in-firmicute-bacteria
#10
REVIEW
Peter Redder
Correct balance between bacterial RNA degradation and synthesis is essential for controlling expression level of all RNAs. The RNA polymerase, which performs the RNA synthesis, is highly conserved across the bacterial domain. However, this is surprisingly not the case for the RNA degradation machinery, which is composed of different subunits and performs different enzymatic reactions, depending on the organism. In Escherichia coli, the RNA decay is performed by the degradosome complex, which forms around the membrane-associated endoribonuclease RNase E, and is stable enough to be purified without falling apart...
January 5, 2018: Wiley Interdisciplinary Reviews. RNA
https://www.readbyqxmd.com/read/29310713/an-imd-like-pathway-mediates-both-endosymbiont-control-and-host-immunity-in-the-cereal-weevil-sitophilus-spp
#11
Justin Maire, Carole Vincent-Monégat, Florent Masson, Anna Zaidman-Rémy, Abdelaziz Heddi
Many insects developing on nutritionally unbalanced diets have evolved symbiotic associations with vertically transmitted intracellular bacteria (endosymbionts) that provide them with metabolic components, thereby improving the host's abilities to thrive on such poor ecological niches. While host-endosymbiont coevolutionary constraints are known to entail massive genomic changes in the microbial partner, host's genomic evolution remains elusive, particularly with regard to the immune system. In the cereal weevil Sitophilus spp...
January 8, 2018: Microbiome
https://www.readbyqxmd.com/read/29305504/an-igaa-umob-family-protein-from-serratia-marcescens-regulates-motility-capsular-polysaccharide-and-secondary-metabolite-production
#12
Nicholas A Stella, Kimberly M Brothers, Jake D Callaghan, Angelina M Passerini, Cihad Sigindere, Preston J Hill, Xinyu Liu, Daniel J Wozniak, Robert M Q Shanks
Secondary metabolites are an important source of pharmaceuticals and key modulators of microbe-microbe interactions. The bacterium Serratia marcescens is part of the Enterobacteriaceae family of eubacteria and produces a number of biologically active secondary metabolites. In this study, we screened for novel regulators of secondary metabolites synthesized by a clinical isolate of S. marcescens and found mutations in a gene for an uncharacterized UmoB/IgaA family member here named gumB Mutation of gumB conferred a severe loss of secondary metabolites prodigiosin and serratamolide...
January 5, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29298384/iron-robustly-stimulates-simultaneous-nitrification-and-denitrification-under-aerobic-conditions
#13
Hong Chen, Xuhao Zhao, Yuying Cheng, Mingji Jiang, Xiang Li, Gang Xue
Simultaneous nitrification and denitrification (SND) is a promising single-reactor biological nitrogen-removal method. Activated sludge with and without iron scrap supplementation (Sludge-Fe and Sludge-C, respectively) was acclimated under aerobic condition. The total nitrogen (TN) content of Sludge-Fe substantially decreased from 25.0±1.0 to 11.2±0.4 mg/L, but Sludge-C did not show the TN-removal capacity. Further investigations excluded a chemical reduction of NO3--N by iron and a decrease of NH4+-N by microbial assimilation, and the contribution of SND was verified...
January 3, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29295912/role-of-heat-shock-proteases-in-quorum-sensing-mediated-regulation-of-biofilm-formation-by-vibrio-species
#14
Kyung-Jo Lee, You-Chul Jung, Soon-Jung Park, Kyu-Ho Lee
Capsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacterium Vibrio vulnificus CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However, V. vulnificus biofilms formed under heat shock conditions did not exhibit the dispersion stage. Transcripts of the CPS gene cluster were at basal levels in the heat-exposed cell owing to reduced cellular levels of SmcR. At least two proteases induced by heat shock, ClpPA and Lon, were responsible for determining the instability of SmcR...
January 2, 2018: MBio
https://www.readbyqxmd.com/read/29286535/the-changing-landscape-of-lynch-syndrome-due-to-pms2-mutations
#15
REVIEW
J Blount, A Prakash
DNA repair pathways are essential for cellular survival as our DNA is constantly under assault from both exogenous and endogenous DNA damaging agents. Five major mammalian DNA repair pathways exist within a cell to maintain genomic integrity. Of these, the DNA mismatch repair (MMR) pathway is highly conserved among species and is well documented in bacteria. In humans, the importance of MMR is underscored by the discovery that a single mutation in any one of four genes within the MMR pathway (MLH1, MSH2, MSH6 and PMS2) results in Lynch syndrome (LS)...
December 29, 2017: Clinical Genetics
https://www.readbyqxmd.com/read/29281823/rna-independent-dna-cleavage-activities-of-cas9-and-cas12a
#16
Ramya Sundaresan, Hari Priya Parameshwaran, S D Yogesha, Mark Walter Keilbarth, Rakhi Rajan
CRISPR-Cas systems provide bacteria and archaea with sequence-specific protection against invading mobile genetic elements. In the presence of divalent metal ions, Cas9 and Cas12a (formerly Cpf1) proteins target and cleave DNA that is complementary to a cognate guide RNA. The recognition of a protospacer adjacent motif (PAM) sequence in the target DNA by Cas9 and Cas12a is essential for cleavage. This RNA-guided DNA targeting is widely used for gene-editing methods. Here, we show that Francisella tularensis novicida (Fno) Cas12a, FnoCas9, and Streptococcus pyogenes Cas9 (SpyCas9) cleave DNA without a guide RNA in the presence of Mn2+ ions...
December 26, 2017: Cell Reports
https://www.readbyqxmd.com/read/29281627/an-essential-regulatory-function-of-the-dnak-chaperone-dictates-the-decision-between-proliferation-and-maintenance-in-caulobacter-crescentus
#17
Frederic D Schramm, Kristina Heinrich, Marietta Thüring, Jörg Bernhardt, Kristina Jonas
Hsp70 chaperones are well known for their important functions in maintaining protein homeostasis during thermal stress conditions. In many bacteria the Hsp70 homolog DnaK is also required for growth in the absence of stress. The molecular reasons underlying Hsp70 essentiality remain in most cases unclear. Here, we demonstrate that DnaK is essential in the α-proteobacterium Caulobacter crescentus due to its regulatory function in gene expression. Using a suppressor screen we identified mutations that allow growth in the absence of DnaK...
December 27, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/29280343/the-ropae-gene-encodes-a-porin-like-protein-involved-in-copper-transit-in-rhizobium-etli-cfn42
#18
Antonio González-Sánchez, Ciro A Cubillas, Fabiola Miranda, Araceli Dávalos, Alejandro García-de Los Santos
Copper (Cu) is an essential micronutrient for all aerobic forms of life. Its oxidation states (Cu+ /Cu2+ ) make this metal an important cofactor of enzymes catalyzing redox reactions in essential biological processes. In gram-negative bacteria, Cu uptake is an unexplored component of a finely regulated trafficking network, mediated by protein-protein interactions that deliver Cu to target proteins and efflux surplus metal to avoid toxicity. Rhizobium etliCFN42 is a facultative symbiotic diazotroph that must ensure its appropriate Cu supply for living either free in the soil or as an intracellular symbiont of leguminous plants...
December 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/29279392/coordinating-carbon-and-nitrogen-metabolic-signaling-through-the-cyanobacterial-global-repressor-ndhr
#19
Yong-Liang Jiang, Xue-Ping Wang, Hui Sun, Shu-Jing Han, Wei-Fang Li, Ning Cui, Gui-Ming Lin, Ju-Yuan Zhang, Wang Cheng, Dong-Dong Cao, Zhi-Yong Zhang, Cheng-Cai Zhang, Yuxing Chen, Cong-Zhao Zhou
The coordination of carbon and nitrogen metabolism is essential for bacteria to adapt to nutritional variations in the environment, but the underlying mechanism remains poorly understood. In autotrophic cyanobacteria, high CO2 levels favor the carboxylase activity of ribulose 1,5 bisphosphate carboxylase/oxygenase (RuBisCO) to produce 3-phosphoglycerate, whereas low CO2 levels promote the oxygenase activity of RuBisCO, leading to 2-phosphoglycolate (2-PG) production. Thus, the 2-PG level is reversely correlated with that of 2-oxoglutarate (2-OG), which accumulates under a high carbon/nitrogen ratio and acts as a nitrogen-starvation signal...
December 26, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29277694/comparative-transcriptomic-analysis-of-shrimp-hemocytes-in-response-to-acute-hepatopancreas-necrosis-disease-ahpnd-causing-vibrio-parahemolyticus-infection
#20
Zhihong Zheng, Fan Wang, Jude Juventus Aweya, Ruiwei Li, Defu Yao, Mingqi Zhong, Shengkang Li, Yueling Zhang
The recent emergence of acute hepatopancreas necrosis disease (AHPND) in shrimps has posed a major challenge in the shrimp aquaculture industry. The Pir toxin proteins carried by some strains of Vibrio parahaemolyticus are believed to play essential roles in the pathogenesis of AHPND. However, few studies have so far explored how the host immune system responds to these bacteria. In this study, AHPND V. parahaemolyticus (with Pir) and non-AHPND V. parahaemolyticus (without Pir) were injected into two groups of shrimps, and the hemocytes collected for comparative transcriptomic analyses...
December 22, 2017: Fish & Shellfish Immunology
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