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https://www.readbyqxmd.com/read/29334654/phbv-polymer-supported-denitrification-system-efficiently-treated-high-nitrate-concentration-wastewater-denitrification-performance-microbial-community-structure-evolution-and-key-denitrifying-bacteria
#1
Zhongshuo Xu, Liyan Song, Xiaohu Dai, Xiaoli Chai
Biodegradable polymer supported denitrification (BPD) system shows good denitrification performance for the wastewater with low nitrate concentrations. In this study, a BPD system using Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polymer as carbon source was developed to treat the wastewater with high nitrate concentrations. The denitrification performance, utilization ratio of PHBV polymers, and microbial community structure evolution and key denitrifying bacteria were comprehensively studied. Results indicated that an average nitrate removal efficiency of 99% could be achieved with an influent NO3--N concentration of 100 mg L-1 and a hydraulic retention time (HRT) of 7...
January 8, 2018: Chemosphere
https://www.readbyqxmd.com/read/29332150/ectoparasite-activity-during-incubation-increases-microbial-growth-on-avian-eggs
#2
G Tomás, D Martín-Gálvez, C Ruiz-Castellano, M Ruiz-Rodríguez, J M Peralta-Sánchez, M Martín-Vivaldi, J J Soler
While direct detrimental effects of parasites on hosts are relatively well documented, other more subtle but potentially important effects of parasitism are yet unexplored. Biological activity of ectoparasites, apart from skin injuries and blood-feeding, often results in blood remains, or parasite faeces that accumulate and modify the host environment. In this way, ectoparasite activities and remains may increase nutrient availability that may favour colonization and growth of microorganisms including potential pathogens...
January 13, 2018: Microbial Ecology
https://www.readbyqxmd.com/read/29330647/absence-of-the-nitrous-oxide-reductase-gene-cluster-in-commercial-alfalfa-inoculants-is-probably-due-to-the-extensive-loss-of-genes-during-rhizobial-domestication
#3
Silvina Brambilla, Romina Frare, Gabriela Soto, Cintia Jozefkowicz, Nicolás Ayub
As other legume crops, alfalfa cultivation increases the emission of the greenhouse gas nitrous oxide (N2O). Since legume-symbiotic nitrogen-fixing bacteria play a crucial role in this emission, it is important to understand the possible impacts of rhizobial domestication on the evolution of denitrification genes. In comparison with the genomes of non-commercial strains, those of commercial alfalfa inoculants exhibit low total genome size, low number of ORFs and high numbers of both frameshifted genes and pseudogenes, suggesting a dramatic loss of genes during bacterial domestication...
January 12, 2018: Microbial Ecology
https://www.readbyqxmd.com/read/29330536/carbon-limitation-drives-gc-content-evolution-of-a-marine-bacterium-in-an-individual-based-genome-scale-model
#4
Ferdi L Hellweger, Yongjie Huang, Haiwei Luo
An important unanswered question in evolutionary genomics is the source of considerable variation of genomic base composition (GC content) even among organisms that share one habitat. Evolution toward GC-poor genomes has been considered a major adaptive pathway in the oligotrophic ocean, but GC-rich bacteria are also prevalent and highly successful in this environment. We quantify the contribution of multiple factors to the change of genomic GC content of Ruegeria pomeroyi DSS-3, a representative and GC-rich member in the globally abundant Roseobacter clade, using an agent-based model...
January 12, 2018: ISME Journal
https://www.readbyqxmd.com/read/29330348/weak-epistasis-may-drive-adaptation-in-recombining-bacteria
#5
Brian J Arnold, Michael U Gutmann, Yonatan H Grad, Samuel K Sheppard, Jukka Corander, Marc Lipsitch, William P Hanage
The impact of epistasis on the evolution of multilocus traits depends on recombination. While sexually-reproducing eukaryotes recombine so frequently that epistasis between polymorphisms is not considered to play a large role in short-term adaptation, many bacteria also recombine, some to the degree that their populations are described as 'panmictic' or 'freely recombining'. However, whether this recombination is sufficient to limit the ability of selection to act on epistatic contributions to fitness is unknown...
January 12, 2018: Genetics
https://www.readbyqxmd.com/read/29325872/structure-and-function-of-a-highly-active-bile-salt-hydrolase-bsh-from-enterococcus-faecalis-and-post-translational-processing-of-bsh-enzymes
#6
Deepak Chand, Priyabrata Panigrahi, Nishant Kumar Varshney, Sureshkumar Ramasamy, C G Suresh
Bile Salt Hydrolase (BSH), a member of Cholylglycine hydrolase family, catalyses the de-conjugation of bile acids and is evolutionarily related to penicillin V acylase (PVA) that hydrolyses a different substrate such as penicillin V. We report the three-dimensional structure of a BSH enzyme from the Gram-positive bacteria Enterococcus faecalis (EfBSH) which has manifold higher hydrolase activity compared to other known BSHs and displays unique allosteric catalytic property. The structural analysis revealed reduced secondary structure content compared to other known BSH structures, particularly devoid of an anti-parallel β-sheet in the assembly loop and part of a β-strand is converted to increase the length of a substrate binding loop 2...
January 8, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29325009/efficient-generation-of-complete-sequences-of-mdr-encoding-plasmids-by-rapid-assembly-of-minion-barcoding-sequencing-data
#7
Ruichao Li, Miaomiao Xie, Ning Dong, Dachuan Lin, Xuemei Yang, Marcus Ho Yin Wong, Edward Wai-Chi Chan, Sheng Chen
Background: Multidrug resistance (MDR)-encoding plasmids are considered major molecular vehicles responsible for transmission of antibiotic resistance genes among bacteria of the same or different species. Delineating the complete sequences of such plasmids could provide valuable insight into the evolution and transmission mechanisms underlying bacterial antibiotic resistance development. However, due to the presence of multiple repeats of mobile elements, complete sequencing of MDR plasmids remains technically complicated, expensive and time-consuming...
January 9, 2018: GigaScience
https://www.readbyqxmd.com/read/29323625/catheter-associated-urinary-tract-infections-in-persons-with-neurogenic-bladders
#8
Todd A Linsenmeyer
This review is based on the author's Donald Munro Lecture given at the annual conference of the Academy of Spinal Cord Injury Professionals in New Orleans, LA. Indwelling catheters play an important role in bladder management following SCI for many individuals with neurogenic bladders. There is an increased risk of UTI compared to other types of bladder management with indwelling urethral catheters but not SP catheters. To minimize the risk of symptomatic UTI, the following steps are essential: prevent bladder wall distention and resulting ischemia, maintain colonization with "good" bacteria, and prevent bladder stones...
January 11, 2018: Journal of Spinal Cord Medicine
https://www.readbyqxmd.com/read/29322462/methods-to-determine-mutational-trajectories-after-experimental-evolution-of-antibiotic-resistance
#9
Douglas L Huseby, Diarmaid Hughes
The evolution of bacterial resistance to antibiotics by mutation within the genome (as distinct from horizontal gene transfer of new material into a genome) could occur in a single step but is usually a multistep process. Resistance evolution can be studied in laboratory environments by serial passage of bacteria in liquid culture or on agar, with selection at constant, or varying, concentrations of drug. Whole genome sequencing can be used to make an initial analysis of the evolved mutants. The trajectory of evolution can be determined by sequence analysis of strains from intermediate steps in the evolution, complemented by phenotypic analysis of genetically reconstructed isogenic strains that recapitulate the intermediate steps in the evolution...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29317070/hypothesis-for-the-cause-and-therapy-of-neurodegenerative-diseases
#10
Philip Serwer
The cause and therapy of neurodegenerative diseases remain unsolved puzzles. These diseases are correlated with presence of beta sheet-rich amyloid assemblies. Here, I derive and assemble puzzle pieces to obtain a loose end-tying hypothesis for cause with direct implications for therapy. I use the following extrapolations to find connectable puzzle pieces: (a) the traditional extrapolation that amyloid/amyloid precursors cause disease, (b) a recent extrapolation that amyloid-forming proteins, some of which are virus protein homologs, are components of an empirically obscure innate immune system that counters insults, including those by both viruses and bacteria, (c) a new extrapolation that various insults produce assemblies with structural features in common and that amyloid-forming, innate immune system proteins recognize these features and, then, counter insults by co-assembly, (d, 1) a second new extrapolation that beta sheet is a common structural feature and is extended during insult-neutralizing co-assembly and (d, 2) an appendix, derived from studies of phages T3 and T4, that most insult-produced assemblies are obscure to current biochemical analysis...
January 2018: Medical Hypotheses
https://www.readbyqxmd.com/read/29316517/functional-metagenomics-reveals-a-novel-carbapenem-hydrolyzing-mobile-beta-lactamase-from-indian-river-sediments-contaminated-with-antibiotic-production-waste
#11
Nachiket P Marathe, Anders Janzon, Stathis D Kotsakis, Carl-Fredrik Flach, Mohammad Razavi, Fanny Berglund, Erik Kristiansson, D G Joakim Larsson
Evolution has provided environmental bacteria with a plethora of genes that give resistance to antibiotic compounds. Under anthropogenic selection pressures, some of these genes are believed to be recruited over time into pathogens by horizontal gene transfer. River sediment polluted with fluoroquinolones and other drugs discharged from bulk drug production in India constitute an environment with unprecedented, long-term antibiotic selection pressures. It is therefore plausible that previously unknown resistance genes have evolved and/or are promoted here...
January 6, 2018: Environment International
https://www.readbyqxmd.com/read/29315884/bacterial-outer-membrane-constriction
#12
REVIEW
Alexander J F Egan
The outer membrane of Gram-negative bacteria is a crucial permeability barrier allowing the cells to survive a myriad of toxic compounds, including many antibiotics. This innate form of antibiotic resistance is compounded by the evolution of more active mechanisms of resistance such as efflux pumps, reducing the already limited number of clinically relevant treatments for Gram-negative pathogens. During cell division Gram-negative bacteria must coordinate constriction of the outer membrane in conjunction with other crucial layers of the cell envelope, the peptidoglycan cell wall and the inner membrane...
January 8, 2018: Molecular Microbiology
https://www.readbyqxmd.com/read/29314762/opportunistic-infections-in-patients-with-idiopathic-inflammatory-myopathies
#13
Ada Redondo-Benito, Adrian Curran, Ana Villar-Gomez, Ernesto Trallero-Araguas, Andreu Fernández-Codina, Iago Pinal-Fernandez, Jose Ángel Rodrigo-Pendás, Albert Selva-O'Callaghan
AIM: To describe the prevalence, clinical characteristics and risk factors of opportunistic infection (OI) in a cohort of patients with inflammatory myopathies, and compare mortality rates between those with and without OIs. METHODS: In total, 204 patients from our myositis cohort were reviewed to identify patients who had experienced an OI during the period 1986-2014. The patients' clinical characteristics, treatments received, and outcomes were systematically recorded...
January 5, 2018: International Journal of Rheumatic Diseases
https://www.readbyqxmd.com/read/29313080/evolution-of-potent-odorants-within-the-volatile-metabolome-of-high-quality-hazelnuts-corylus-avellana-l-evaluation-by-comprehensive-two-dimensional-gas-chromatography-coupled-with-mass-spectrometry
#14
Marta Cialiè Rosso, Erica Liberto, Nicola Spigolon, Mauro Fontana, Marco Somenzi, Carlo Bicchi, Chiara Cordero
Within the pattern of volatiles released by food products (volatilome), potent odorants are bio-active compounds that trigger aroma perception by activating a complex array of odor receptors (ORs) in the regio olfactoria. Their informative role is fundamental to select optimal post-harvest and storage conditions and preserve food sensory quality. This study addresses the volatile metabolome from high-quality hazelnuts (Corylus avellana L.) from the Ordu region (Turkey) and Tonda Romana from Italy, and investigates its evolution throughout the production chain (post-harvest, industrial storage, roasting) to find functional correlations between technological strategies and product quality...
January 9, 2018: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29312538/genome-wide-gene-expression-analysis-in-the-amphioxus-branchiostoma-belcheri-after-poly-i-c-challenge-using-strand-specific-rna-seq
#15
Qi-Lin Zhang, Zheng-Qing Xie, Ming-Zhong Liang, Bang Luo, Xiu-Qiang Wang, Jun-Yuan Chen
The gene expression associated with immune response to bacteria/bacterial mimic has been extensively analyzed in amphioxus, but remains largely unknown about how gene are involved in the immune response to viral invasion at expression level. Here, we analyze the rRNA-depleted transcriptomes of Branchiostoma belcheri using strand-specific RNA-seq in response to the viral mimic, poly (I:C) (pIC). A total of 5,317 differentially expressed genes were detected at treatment group by comparing with control. The gene with the most significant expression changes (top 15) after pIC challenge and 7 immune-related categories involving 58 differently expressed genes were scrutinized...
December 12, 2017: Oncotarget
https://www.readbyqxmd.com/read/29311700/phage-host-population-dynamics-promotes-prophage-acquisition-in-bacteria-with-innate-immunity
#16
Maroš Pleška, Moritz Lang, Dominik Refardt, Bruce R Levin, Călin C Guet
Temperate bacteriophages integrate in bacterial genomes as prophages and represent an important source of genetic variation for bacterial evolution, frequently transmitting fitness-augmenting genes such as toxins responsible for virulence of major pathogens. However, only a fraction of bacteriophage infections are lysogenic and lead to prophage acquisition, whereas the majority are lytic and kill the infected bacteria. Unless able to discriminate lytic from lysogenic infections, mechanisms of immunity to bacteriophages are expected to act as a double-edged sword and increase the odds of survival at the cost of depriving bacteria of potentially beneficial prophages...
January 8, 2018: Nature Ecology & Evolution
https://www.readbyqxmd.com/read/29311232/context-dependent-requirements-for-fimh-and-other-canonical-virulence-factors-in-gut-colonization-by-extraintestinal-pathogenic-escherichia-coli
#17
Colin W Russell, Brittany A Fleming, Courtney A Jost, Alexander Tran, Alan T Stenquist, Morgan A Wambaugh, Mary P Bronner, Matthew A Mulvey
Extraintestinal pathogenic Escherichia coli (ExPEC) act as commensals within the mammalian gut, but can induce pathology upon dissemination to other host environments such as the urinary tract and bloodstream. ExPEC genomes are likely shaped by evolutionary forces encountered within the gut where the bacteria spend much of their time, provoking the question of how their extraintestinal virulence traits arose. The principle of coincidental evolution, in which a gene that evolved in one niche happens to be advantageous in another, has been used to argue that ExPEC virulence factors originated in response to selective pressures within the gut ecosystem...
January 8, 2018: Infection and Immunity
https://www.readbyqxmd.com/read/29310713/an-imd-like-pathway-mediates-both-endosymbiont-control-and-host-immunity-in-the-cereal-weevil-sitophilus-spp
#18
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/29307013/the-coronafacoyl-phytotoxins-structure-biosynthesis-regulation-and-biological-activities
#19
Dawn R D Bignell, Zhenlong Cheng, Luke Bown
Phytotoxins are secondary metabolites that contribute to the development and/or severity of diseases caused by various plant pathogenic microorganisms. The coronafacoyl phytotoxins are an important family of plant toxins that are known or suspected to be produced by several phylogenetically distinct plant pathogenic bacteria, including the gammaproteobacterium Pseudomonas syringae and the actinobacterium Streptomyces scabies. At least seven different family members have been identified, of which coronatine was the first to be described and is the best-characterized...
January 6, 2018: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/29306009/genotyping-and-high-flux-sequencing-of-the-bacterial-pathogenic-elements-integrons
#20
REVIEW
Yanmei Li, Ling Yang, Jie Fu, Muxia Yan, Dingqiang Chen, Li Zhang
Regarded as a common genetic element responsible for horizontal gene transfer and wide spread of antimicrobial resistance among a large variety of bacteria, integrons are commonly distributed and considered as a determinant in the acquisition and evolution of virulence and antibiotic resistance. To date, the surveillances of integrons have been widely conducted in clinic, community even husbandry. For exact and accurate integron screening, as well as resistant cassettes, reliable monitoring methods is need...
January 3, 2018: Microbial Pathogenesis
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