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Canadian Journal of Microbiology

Shawn Lewenza, Laetitia Mazenod, Shirin Afroj, Erik van Tilburg Bernardes
Biofilms are dense communities of bacteria enmeshed in a protective extracellular matrix composed mainly of exopolysaccharides (EPS), extracellular DNA (eDNA), proteins and outer membrane vesicles (OMV). Given the role of biofilms in antibiotic tolerant and chronic infections, novel strategies are needed to block, disperse or degrade biofilms. Enzymes that degrade the biofilm matrix are a promising new therapy. We screened mutants in many of the enzymes secreted by the type II secretion system (T2SS) and determined that the T2SS, and specifically phospholipases, play a role in biofilm formation...
June 13, 2017: Canadian Journal of Microbiology
Ahmad Esmaeili Taheri, Syama Chatterton, Bruce Gossen, Debra McLaren
Oomycetes are a diverse group of microorganisms, however, little is known about their composition and biodiversity in agroecosystems. Illumina MiSeq was used to determine the type and abundance of oomycetes associated with pea root rot in the Canadian prairies. Additional objectives of the study were to identify differences in oomycete communities associated with pea root health and compare oomycete communities between the 3 prairie provinces where field peas are commonly cultivated. Samples of soil from the rhizosphere of field pea (Pisum sativum L...
June 2, 2017: Canadian Journal of Microbiology
Ahmad Esmaeili Taheri, Syama Chatterton, Bruce Gossen, Debra McLaren
Metagenomic analysis of oomycetes through deep amplicon sequencing has been conducted primarily using the ITS6/ ITS7 primer set that targets the ITS1 region. While this primer set shows a perfect match to most oomycete taxa, ITS7 contains three mismatches to the corresponding binding site of plant pathogens within the genus Aphanomyces. PCR efficiency differs for taxa with uneven primer matching characteristics, which may explain why previous studies have detected this genus at low abundance. To overcome the impact of these mismatches on PCR sensitivity, the mismatched nucleotides were replaced with degenerate nucleotides...
June 2, 2017: Canadian Journal of Microbiology
Arpeeta Ganguly, Rolf Dieter Joerger
The open reading frames (ORFs), SEN0085 and SeKA_A4361, from Salmonella enterica Enteritidis NalR and Kentucky 3795, corresponding to the acid-inducible sulfatase gene, aslA from S. e Typhimurium, were previously suggested by microarray analysis to be differentially expressed under acid conditions. However, growth and enzyme activity tests in the present study demonstrated that both wild type strains exhibited sulfatase activity with 4-nitrophenyl sulfate and 5-bromo-4-chloro-3 indolyl sulfate at pH 5.5. The acid sulfatase does not appear to be involved in sugar sulfate, tyrosine sulfate and 4-hydroxy-3-methoxyphenylglycol sulfate, heparin or chondroitin sulfate hydrolysis at pH 5...
May 30, 2017: Canadian Journal of Microbiology
Jasmine M Pando, Richard F Pfeltz, Jesus A Cuaron, Vijayaraj Nagarajan, Mukti N Mishra, Nathanial J Torres, Mohamed O Elasri, Brian J Wilkinson, John E Gustafson
Transcriptional profiles of two unrelated clinical methicillin-resistant S. aureus (MRSA) isolates were analyzed following 10 % v/v ethanol challenge (15 min), which arrested growth but did not reduce viability. Ethanol-induced stress (EIS) resulted in differential gene expression of 1091 genes, 600 common to both strains, of which 291 were up-regulated. With the exception of the down-regulation of genes involved with osmotic stress functions, EIS resulted in the up-regulation of genes that contribute to stress response networks, notably those altered by oxidative stress, protein quality control in general, and heat shock in particular...
May 18, 2017: Canadian Journal of Microbiology
Wondwosen Tena, Endalkachew Wolde-Meskel, Tulu Degefu, Fran Walley
Forty-two chickpea-nodulating rhizobia were isolated from soil samples collected from diverse agro-ecological locations of Ethiopia, and characterized based on 76 phenotypic traits. Furthermore, 18 representative strains were selected and characterized using multilocus sequence analyses (MLSA) of core and symbiotic gene loci. Numerical analysis of the phenotypic characteristics grouped the 42 strains in to four distinct clusters. The analysis of the 16S rRNA gene of the 18 strains showed that they belong to the Mesorhizobium genus...
May 12, 2017: Canadian Journal of Microbiology
Tiansen Li, Zhixia Tong, Meiling Huang, Liyan Tang, Hui Zhang, Chuangfu Chen
Brucella is Gram-negative intracellular bacterial pathogen that infects humans and animals and contributes to great economic losses in developing countries. Presently, live attenuated Brucella vaccines (B. melitensis strain M5-90) are the most effective means of brucellosis control and prevention in animals. However, these vaccines have several drawbacks, such as an inability to distinguish between a natural infection and immunization and an association with abortions in pregnant animals. Therefore, this study constructed a Brucella M5-90△bp26 mutant and evaluated its virulence...
May 8, 2017: Canadian Journal of Microbiology
N R Abady, C J D Guglielmino, R M Graham, J Adelskov, H V Smith, B K C Patel, A V Jennison
Neisseria meningitidis serogroups B and C have been responsible for the majority of invasive meningococcal disease in Australia, with serogroup B strains causing an increasing proportion of cases in recent years. Serogroup Y has typically caused sporadic disease in Australia. In 2002, a cluster of 4 cases was reported from a rural region in Queensland. Three of these cases were serogroup C, with 1 case diagnosed by molecular detection only, and the fourth case was identified as a serogroup Y infection. Genomic analysis, including antigen finetyping, multilocus sequence typing (MLST), and core genome MLST, demonstrated that the serogroup Y case, though spatially and temporally linked to a serogroup C disease cluster, was not the product of a capsule switch and that one of the serogroup C isolates had a deletion of the entire porA sequence...
May 1, 2017: Canadian Journal of Microbiology
Iman M Bilto, Tuhin Kumar Guha, Alvan Wai, Georg Hausner
In vitro characterization of three LAGLIDADG-type homing endonucleases (I-CcaI, I-CcaII and I-AstI) that belong to the I-OnuI family showed that they are functional homing endonucleases that cleave their respective cognate target sites. These endonucleases are encoded within group ID introns and appear to be orthologs that have inserted into three different mitochondrial genes, rns, rnl and cox3, respectively. The endonuclease activity of I-CcaI was tested using various substrates and its minimum DNA recognition sequence was estimated to be 26 nt...
April 17, 2017: Canadian Journal of Microbiology
Fenge Li, Mingcong Li, Wenchong Shi, Han Li, Zhongtao Sun, Zheng Gao
Denitrification was considered to be the critical process removing reactive nitrogen in estuarine ecosystem. In the present study, the abundance, diversity and community structure of nirK- and nirS-type denitrifiers were compared in sediments from the Yellow River estuary. Quantitative PCR (qPCR) showed that the abundance of the two types denitrifiers performed different distribution patterns among the samples, indicating their distinct habitat preference. Phylogenetic analysis revealed that the most sequences from cluster Ⅰ, Ⅲ, Ⅳ, Ⅴ for nirK-type denitrifiers were dominant distributed at the lower dissolved oxygen (DO) sites and sequences in other clusters were dominant at higher DO area...
April 17, 2017: Canadian Journal of Microbiology
Sabbir R Shuvo, Uliana Kovaltchouk, Abdullah Zubaer, Ayush Kumar, William A T Summers, Lynda J Donald, Georg Hausner, Deborah A Court
Mitochondrial porin, which forms voltage-dependent anion-selective channels (VDAC) in the outer membrane, can be folded into a 19-β-stranded barrel. The N terminus of the protein is external to the barrel and contains α-helical structure. Targeted modifications of the N-terminal region have been assessed in artificial membranes, leading to different models for gating in vitro. However, the in vivo requirements for gating and the N-terminal segment of porin are less well-understood. Using Neurospora crassa porin as a model, the effects of a partial deletion of the N-terminal segment were investigated...
April 17, 2017: Canadian Journal of Microbiology
Karen Gibb, Xavier Schobben, Keith Christian
Tree frogs commonly access drinking water tanks; this may have human health implications. Although amphibians might not be expected to host mammalian faecal indicator bacteria (FIB), it is possible that they may have human FIB on their skin after exposure to human waste. We collected faeces and skin wash from green tree frogs (Litoria caerulea) from a natural environment, a suburban site, and a suburban site near a creek occasionally contaminated with sewage effluent. We used molecular techniques to test for FIB that are routinely used to indicate human faecal contamination...
April 17, 2017: Canadian Journal of Microbiology
Gavin Kernaghan, Michael Mayerhofer, Amanda Griffin
Plants are colonized by diverse assemblages of fungal endophytes that have potential as biocontrol agents for a variety of crops, including grapevine. Although the diversity of symbionts can be very high in wild plants, the fungal endophytes of wild Vitis plants have not yet been investigated. We surveyed the fungal endophytes of 6 wild populations of Vitis riparia, as well as a cold-tolerant, hybrid grapevine in 5 vineyards (1 certified organic), using 454 pyrosequencing. We detected between 43 and 235 operational taxonomic units per sample, with the highest richness and diversity in the wild, the lowest in conventional vineyards, and intermediate levels in the organic vineyard...
April 13, 2017: Canadian Journal of Microbiology
David R McMullin, Justin B Renaud, Tharcisse Barasubiye, Mark W Sumarah, J David Miller
Buildings that have been flooded often have high concentrations of Trichoderma spores in the air while drying. Inhaled spores and spore and mycelial fragments contain large amounts of fungal glucan and natural products that contribute to the symptoms associated with indoor mould exposures. In this study, we considered both small molecules and peptaibol profiles of T. atroviride, T. koningiopsis, T. citrinoviride, and T. harzianum strains obtained from damp buildings in eastern Canada. Twenty-residue peptaibols and sorbicillin-derived metabolites (1-6) including a new structure, (R)-vertinolide (1), were characterized from T...
April 6, 2017: Canadian Journal of Microbiology
Josiele Polzin de Oliveira-Francesquini, Mariangela Hungria, Daiani Cristina Savi, Chirlei Glienke, Rodrigo Aluizio, Vanessa Kava, Lygia Vitória Galli-Terasawa
In this study, we evaluated the diversity of rhizobia isolated from root nodules on common bean (<i>Phaseolus vulgaris</i>) derived from Andean and Mesoamerican centers and grown under field and greenhouse conditions. Genetic characterization of isolates was performed by sequencing analyses of the 16S rRNA and two housekeeping genes, <i>rec</i>A and <i>gln</i>II, and by the amplification of <i>nif</i>H. Symbiotic efficiency was evaluated by examining nodulation, plant-biomass production and plant-N accumulation...
April 4, 2017: Canadian Journal of Microbiology
Riaz Ullah, Muhammad Yasir, Imran Khan, Fehmida Bibi, Sayed Sartaj Sohrab, Ahmed Al-Ansari, Fahad Al-Abbasi, Abdulmohsin Al-Sofyani, Ihsanullah Daur, Seon Woo Lee, Esam I Azhar
Mangrove habitats are ecologically important ecosystems that are under severe pressure worldwide because of environmental changes and human activities. In this study, 16S rRNA gene amplicon deep-sequencing was used to compare bacterial communities in Red Sea mangrove ecosystems at anthropogenically influenced coastal sites and a relatively pristine island site. In total, 32 phyla were identified from the mangrove rhizospheres, with Proteobacteria predominating at each of the studied sites; however, the relative abundance was significantly decreased at the coastal sites (Mastorah, MG-MS and Ar-Rayis, MG-AR) compared with the pristine island site near Dhahban (MG-DBI)...
April 4, 2017: Canadian Journal of Microbiology
Rahul Ukey, William E Holmes, Rakesh Bajpai, Andrei Y Chistoserdov
Acinetobacter baylyi is one of few Gram-negative bacteria capable of accumulating storage lipids in the form of triacylglycerides and wax esters, which makes it an attractive candidate for production of lipophilic products, including biofuel precursors. Thioesterases play a significant dual role in the triacylglyceride and wax ester biosynthesis by either providing or removing acyl-CoA from this pathway. Therefore, 4 different thioesterase genes were cloned from Acinetobacter baylyi ADP1 and expressed in Escherichia coli to investigate their contribution to free fatty acids (FFAs) accumulation...
April 2017: Canadian Journal of Microbiology
Kari Dunfield, Christopher Yost
No abstract text is available yet for this article.
April 2017: Canadian Journal of Microbiology
Shuhuan Li, Jie Wang, Nanxiong Gao, Lizhu Liu, Yahua Chen
The plant-growth-promoting rhizobacterium (PGPR) Y4-4 was isolated from plant rhizosphere soil and identified as Pantoea sp. by 16S rRNA sequence analysis. The effects of strain Y4-4 on alfalfa grown in heavy-metals-contaminated soil was investigated using a pot experiment. In a Cu-rich environment, the shoot dry mass and total dry mass of plants inoculated with strain Y4-4 increased by 22.6% and 21%, and Cu accumulation increased by 15%. In a Pb-Zn-rich environment, the shoot dry mass and total dry mass of plants inoculated with strain Y4-4 increased by 23...
April 2017: Canadian Journal of Microbiology
Ying Zhang, Dongmei Yan, Lin Xia, Xin Zhao, George Osei-Adjei, Shungao Xu, Xiumei Sheng, Xinxiang Huang
Bacterial noncoding RNAs (ncRNA) regulate diverse cellular processes, including virulence and environmental fitness. The malS 5' untranslated region (named malS-5'UTR) was identified as a regulatory ncRNA that increases the invasive capacity of Salmonella enterica serovar Typhi. An IntaRNA search suggested base pairing between malS-5'UTR and hisG mRNA, a key gene in the histidine biosynthetic pathway. Overexpression of malS-5'UTR markedly reduced bacterial growth in minimal medium without histidine. Overexpression of malS-5'UTR increased mRNA from his operon genes, independently of the bax gene, and decreased HisG protein in Salmonella Typhi...
April 2017: Canadian Journal of Microbiology
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