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Applied and Environmental Microbiology

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https://www.readbyqxmd.com/read/28526796/sulfide-induced-dissimilatory-nitrate-reduction-to-ammonium-supports-anammox-in-an-open-water-unit-process-wetland
#1
Zackary L Jones, Justin T Jasper, David L Sedlak, Jonathan O Sharp
Open-water unit process wetlands host a benthic diatomaceous and bacterial assemblage capable of nitrate removal from treated municipal wastewater with unexpected contributions from anammox processes. In exploring mechanistic drivers of anammox, 16S rRNA gene sequencing profiles of the biomat revealed significant microbial community shifts along the flow path and with depth. Notably there was an increasing abundance of sulfate reducers (Desulfococcus and other Deltaproteobacteria) and anammox microorganisms (Brocadiaceae) with depth...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526795/exploring-a-possible-link-between-the-intestinal-microbiota-and-feed-efficiency-in-pigs
#2
Ursula M McCormack, Tânia Curião, Stefan G Buzoianu, Maria L Prieto, Tomas Ryan, Patrick Varley, Fiona Crispie, Elizabeth Magowan, Barbara U Metzler-Zebeli, Donagh Berry, Orla O'Sullivan, Paul D Cotter, Gillian E Gardiner, Peadar G Lawlor
Feed efficiency (FE) is critical in pig production for both economic and environmental reasons. As the intestinal microbiota plays an important role in energy harvest, it is likely to influence FE. Our aim was therefore to characterize the intestinal microbiota of pigs ranked as low, medium and high residual feed intake (RFI; a metric for FE), where genetic, nutritional and management effects were minimized, in order to explore a possible link between the intestinal microbiota and FE. Eighty one pigs were ranked on RFI between weaning and day 126 post-weaning, and 32 were selected as the extremes in RFI (12 low, 10 medium, 10 high)...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526794/raffinose-induces-biofilm-formation-by-streptococcus-mutans-in-low-concentrations-of-sucrose-by-increasing-production-of-extracellular-dna-and-fructan
#3
Ryo Nagasawa, Tsutomu Sato, Hidenobu Senpuku
Streptococcus mutans is the primary etiological agent of dental caries and causes tooth decay by forming a firmly attached biofilm on tooth surfaces. Biofilm formation is induced by the presence of sucrose, which is a substrate for the synthesis of extracellular polysaccharides, but not in the presence of oligosaccharides. Nonetheless, in this study, we found that raffinose, which is an oligosaccharide with an intestinal regulatory function and antiallergic effect, induced biofilm formation by S. mutans in a mixed culture with sucrose which was at concentrations less than those required to induce biofilm formation directly...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526793/genomic-analysis-of-calderihabitans-maritimus-kkc1-a-thermophilic-hydrogenogenic-carboxydotrophic-bacterium-isolated-from-marine-sediment
#4
Kimiho Omae, Yasuko Yoneda, Yuto Fukuyama, Takashi Yoshida, Yoshihiko Sako
Calderihabitans maritimus KKC1 is a thermophilic hydrogenogenic carboxydotroph isolated from a submerged marine caldera. Here, we describe the de novo sequencing and feature analysis of the C. maritimus KKC1 genome. Genome-based phylogenetic analysis confirmed that C. maritimus KKC1 was most closely related to the genus Moorella, which includes well-studied acetogenic members. Comparative genomic analysis revealed that, like Moorella, C. maritimus KKC1 retained both the CO2-reducing Wood-Ljungdahl pathway and energy-converting hydrogenase-based module activated by reduced ferredoxin, but lacked the HydABC and NfnAB electron bifurcating enzymes and pyruvate:ferredoxin oxidoreductase required for ferredoxin reduction during acetogenic growth...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526792/environmental-spread-of-ndm-1-producing-multi-drug-resistant-bacteria-in-dhaka-bangladesh
#5
Mohammad Aminul Islam, Moydul Islam, Rashedul Hasan, M Iqbal Hossain, Ashikun Nabi, Mahdia Rahman, Wil H F Goessens, Hubert P Endtz, Alexandria B Boehm, Shah M Faruque
Resistance to carbapenem antibiotics through the production of New Delhi Metallo-β-lactamase-1 (NDM-1) constitutes an emerging challenge in the treatment of bacterial infections. To monitor possible source of spread of these organisms in Dhaka, Bangladesh, we conducted comparative analysis of waste water samples from hospital adjacent areas (HAR) and from community areas (COM) as well as public tap water samples for the occurrence and characteristics of NDM-1 producing bacteria. Of 72 HAR samples tested 51 (71%) were positive for NDM-1-producing bacteria as evidenced by phenotypic tests and the presence of blaNDM-1 gene, compared to 5 of 41 (12...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526791/pseudomonas-chlororaphis-produces-two-distinct-r-tailocins-that-contribute-to-bacterial-competition-in-biofilms-and-on-roots
#6
Robert J Dorosky, Jun Myoung Yu, Leland S Pierson, Elizabeth A Pierson
R-type tailocins are high molecular weight bacteriocins that resemble bacteriophage tails and are encoded within the genomes of many Pseudomonas species. In this study, analysis of the P. chlororaphis 30-84 R-tailocin gene cluster revealed that it encodes the structural components to produce two R-tailocins of different ancestral origin. Two distinct R-tailocin populations differing in length were observed in UV induced lysates of P. chlororaphis 30-84 via transmission electron microscopy. Mutants defective in the production of one or both R-tailocins demonstrated that the killing spectrum of each tailocin is limited to Pseudomonas species...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526790/post-epizootic-persistence-of-asymptomatic-mycoplasma-conjunctivae-infection-in-iberian-ibex
#7
Xavier Fernández-Aguilar, Oscar Cabezón, José Enrique Granados, Joachim Frey, Emmanuel Serrano, Roser Velarde, Francisco Javier Cano-Manuel, Gregorio Mentaberre, Arián Ráez-Bravo, Paulino Fandos, Jorge Ramón López-Olvera
The susceptibility of Iberian ibex (Capra pyrenaica) to Mycoplasma conjunctivae ocular infection and the changes in their interaction over time were studied in terms of clinical outcome, molecular detection and IgG immune response in a captive population that underwent a severe infectious keratoconjunctivitis (IKC) outbreak. Mycoplasma conjunctivae was detected for the first time in the Iberian ibexes coinciding with the IKC outbreak. Its prevalence had a decreasing trend in 2013 that was consistent with the clinical resolution (August 35...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526789/a-novel-iron-dependent-enzyme-that-catalyzes-the-initial-step-in-the-biodegradation-of-n-nitroglycine-by-variovorax-sp-strain-js1663
#8
Kristina M Mahan, Hangping Zheng, Tekle T Fida, Ronald J Parry, David E Graham, Jim C Spain
Nitramines are key constituents of most of the explosives in current use and consequently contaminate soil and groundwater at many military facilities around the world. Toxicity from nitramine contamination poses a health risk to plants and animals, thus understanding how nitramines are biodegraded is critical to environmental remediation. The biodegradation of synthetic nitramine compounds such as hexahydro-1,3,5-trinitro-1,3,5- triazine (RDX) has been studied for decades, but little is known about the catabolism of naturally produced nitramine compounds...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526788/zinc-resistance-within-swine-associated-methicillin-resistant-staphylococcus-aureus-mrsa-isolates-in-the-usa-is-associated-with-mlst-lineage
#9
Samantha J Hau, Timothy Frana, Jisun Sun, Peter R Davies, Tracy L Nicholson
Zinc resistance in livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) sequence type (ST) 398 is primarily mediated by the czrC gene co-located with the mecA gene, encoding methicillin resistance, within the type V SCCmec element. Because czrC and mecA are located within the same mobile genetic element, it has been suggested that the use of in feed zinc as an antidiarrheal agent has the potential to contribute to the emergence and spread of MRSA in swine through increased selection pressure to maintain the SCCmec element in isolates obtained from pigs...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526787/development-of-multi-well-plate-methods-using-pure-cultures-of-methanogens-to-identify-new-inhibitors-for-suppressing-ruminant-methane-emissions
#10
M R Weimar, J Cheung, D Dey, C McSweeney, M Morrison, Y Kobayashi, W B Whitman, V Carbone, L R Schofield, R S Ronimus, G M Cook
Hydrogenotrophic methanogens typically require strictly anaerobic culturing conditions in glass tubes with overpressures of H2 and CO2 that are both time-consuming and costly. To increase the throughput for screening chemical compound libraries, 96-well microtiter plate methods for the growth of a marine (environmental) methanogen Methanococcus maripaludis strain S2 and the rumen methanogen Methanobrevibacter species AbM4 were developed. A number of key parameters (inoculum size, reducing agents for media preparation, duration of assay, inhibitor solvents and culture volume) were optimised to achieve robust and reproducible growth in a high-throughput microtiter plate format...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526786/impact-of-acanthamoeba-cysts-on-stress-resistance-of-salmonella-enterica-serovar-typhimurium-yersinia-enterocolitica-4-o-3-listeria-monocytogenes-1-2a-and-escherichia-coli-o-26
#11
Ellen Lambrecht, Julie Baré, Koen Sabbe, Kurt Houf
The formation of robust resting cysts enables Acanthamoeba to resist harsh environmental conditions. This study investigated to what extent these cysts are resistant to physical and chemical stresses as applied in food industry cleaning and disinfection procedures. Moreover it was assessed whether certain intracystic meatborne bacterial pathogens are more stress-resistant than free-living bacterial monocultures and if intracystic passage and subsequent association with trophozoites induces cross-tolerance towards other stressors...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526785/effects-of-arginine-on-growth-virulence-gene-expression-and-stress-tolerance-by-streptococcus-mutans
#12
Brinta Chakraborty, Robert A Burne
Streptococcus mutans is a common constituent of oral biofilms and a primary etiologic agent of human dental caries. The bacteria associated with dental caries have a potent ability to produce organic acids from dietary carbohydrates and to grow and metabolize in acidic conditions. In contrast, many commensal bacteria produce ammonia through the arginine deiminase system (ADS), which moderates the pH of oral biofilms. Arginine metabolism by the ADS is a significant deterrent to the initiation and progression of dental caries...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500046/roxb-is-a-novel-type-of-rubber-oxygenase-that-combines-properties-of-rubber-oxygenase-roxa-and-latex-clearing-protein-lcp
#13
Jakob Birke, Wolf Röther, Dieter Jendrossek
Only two types of rubber oxygenases, rubber oxygenase (RoxA) and latex clearing protein (Lcp), have been described so far. RoxAs are c-type cytochromes of ≈70 kDa produced by Gram-negative rubber-degrading bacteria and cleave polyisoprene into 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD), a C15 oligo-isoprenoid, as major end product. Lcps are common among Gram-positive rubber-degraders and don't share amino acid sequence similarities with RoxA proteins (RoxAs). Furthermore, Lcps have much smaller molecular masses (≈40 kDa), are b-type cytochromes and cleave polyisoprene to a mixture of C20, C25, C30 and higher oligo-isoprenoids as end products...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500045/sodium-lactate-negatively-regulates-biofilm-formation-of-shewanella-putrefaciens-cn32-via-a-three-component-regulatory-system-lrbs-a-r
#14
Cong Liu, Jinshui Yang, Liang Liu, Baozhen Li, Hongli Yuan, Weijie Liu
The capability of biofilm formation has a major impact on the industrial and biotechnological applications of Shewanella putrefaciens CN32. However, the detailed regulatory mechanisms underlying biofilm formation in S. putrefaciens CN32 remain largely unknown. In the present study, we describe a three-component regulatory system which negatively regulates the biofilm formation of S. putrefaciens CN32. The three-component regulatory system consists of a histidine kinase LrbS (Sputcn32_0303) and two cognate response regulators including a transcription factor LrbA (Sputcn32_0304) and a phosphodiesterase LrbR (Sputcn32_0305)...
May 12, 2017: Applied and Environmental Microbiology
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
#15
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/28500043/potential-for-water-borne-and-invertebrate-transmission-of-west-nile-virus-in-the-great-salt-lake-utah
#16
Melissa Lund, Valerie Shearn-Bochsler, Robert J Dusek, Jan Shivers, Erik Hofmeister
In November and December of 2013, a large mortality event involving 15,000 - 20,000 eared grebes (Podiceps nigricollis) occurred at the Great Salt Lake (GSL), UT. The onset of the outbreak in grebes was followed by a mortality event in > 86 bald eagles (Haliaeetus leucocephalus). During the die-off, West Nile virus (WNV) was detected by RT-PCR or viral culture in carcasses of grebes and eagles submitted to the National Wildlife Health Center. However, no mosquito activity, the primary vector of WNV, was detected by the State of Utah's WNV monitoring program...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500042/carboxyl-analogue-of-mutacin-1140-a-scaffold-for-lead-antibacterial-discovery
#17
Jerome Escano, Akshaya Ravichandran, Bita Salamat, Leif Smith
Mutacin 1140 belongs to the epidermin group of lantibiotics. Epidermin class lantibiotics are ribosomally synthesized and post translationally modified antibiotics with potent activity against Gram-positive bacteria. In particular, this class is effective at targeting drug resistant Streptococcus pneumoniae, MRSA,Mycobacterium tuberculosis, and Clostridium difficile A C-terminal S-[(Z)-2-aminovinyl]-D-cysteine (AviCys) residue is derived from a decarboxylation of a terminal cysteine that is involved in one of the lanthionine ring formation...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500041/evaluation-of-a-real-time-pcr-method-for-detection-of-salmonella-spp-in-environmental-samples
#18
Kuppuswamy N Kasturi, Tomas Drgon
Methods currently used for detecting Salmonella in environmental samples require two days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA, group D, and Enteritidis serovar were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non-Salmonella organisms. The invA and group D specific sets identified all the isolates accurately...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500040/a-novel-sampling-method-for-assessing-human-pathogen-interactions-in-the-natural-environment-using-boot-socks-and-citizen-scientists-with-an-application-to-the-seasonality-of-campylobacter
#19
Natalia R Jones, Caroline Millman, Mike van der Es, Miroslava Hukelova, Ken J Forbes, Catherine Glover, Sam Haldenby, Paul R Hunter, Kathryn Jackson, Sarah J O'Brien, Dan Rigby, Norval J C Strachan, Nicola Williams, Iain R Lake
This paper introduces a novel method for sampling pathogens in natural environments. It uses fabric boot socks worn over walkers' shoes allowing collection of composite samples over large areas. Wide area sampling is better suited to studies focussing upon human exposure to pathogens (e.g. recreational walking). This sampling method is implemented using a Citizen Science approach: groups of three walkers wearing boot socks undertook one of six routes, 40 times over 16 months in the North West (NW) and East Anglian (EA) regions of England...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28500039/selected-probiotic-lactobacilli-have-the-capacity-to-hydrolyze-gluten-peptides-during-simulated-gastro-intestinal-digestion
#20
Ruggiero Francavilla, Maria De Angelis, Carlo Giuseppe Rizzello, Noemi Cavallo, Fabio Dal Bello, Marco Gobbetti
The aim of this study was to demonstrate the capacity of probiotic lactobacilli to hydrolyze immunogenic gluten peptides. Eighteen commercial strains of probiotic lactobacilli with highly variable peptidase activity (i.e., aminopeptidase N, iminopeptidase, prolyl endopeptidyl peptidase, tripeptidase, prolidase, prolinase and dipeptidase), including towards Pro-rich peptides, were tested in this study. Ten probiotic strains were selected based on their specific enzyme activity. When pooled, these ten strains provide the peptidase portfolio that is required to completely degrade the immunogenic gluten peptides involved in celiac disease (CD)...
May 12, 2017: Applied and Environmental Microbiology
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