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Canadian Journal of Microbiology

Caroline Peixoto Bastos, Milena Tomasi Bassani, Marcia Magalhães Mata, Graciela Volz Lopes, Wladimir Padilha Silva
<i>Staphylococcus aureus</i> is an important pathogen of foodborne origin. The pathogen produces a variety of toxins that includes the staphylococcal enterotoxin (SE). The present study aimed to evaluate the prevalence and expression of five SE genes (<i>sea</i>, <i>seb</i>, <i>sec</i>, <i>sed</i>, and <i>see</i>) in <i>S. aureus</i> isolated from outbreaks occurred in the Rio Grande do Sul state, Brazil. All isolates, with the exception of two, presented the same or higher transcriptional expression than the reference strains for at least one of these genes...
August 18, 2017: Canadian Journal of Microbiology
Maria S Stietz, Christina Lopez, Osasumwen Osifo, Marcelo Tolmasky, Silvia T Cardona
There are hundreds of essential genes in multidrug resistant bacterial genomes, but only a few of their products are exploited as antibacterial targets. An example is the electron flavoprotein (ETF) which is required for growth and viability in <i>Burkholderia cenocepacia</i>. Here, we evaluated ETF as an antibiotic target for <i>Burkholderia cepacia</i> complex (Bcc). Depletion of the bacterial ETF during infection of <i>Caenorhabditis elegans</i> significantly extended survival of the nematodes, proving that ETF is essential for survival of <i>B...
August 17, 2017: Canadian Journal of Microbiology
Martino Adamo, Samuele Voyron, Mariangela Girlanda, Roland Marmeisse
Wood decomposition is a key step of the terrestrial carbon cycle and of economic importance. It is essentially a microbiological process performed by fungi and to an unknown extent by bacteria. To gain access to the genes expressed by the diverse microbial communities participating to wood decay we developed an RNA extraction protocol from this recalcitrant material rich in polysaccharides and phenolic compounds. This protocol was implemented on 22 wood samples representing as many tree species from 11 plant families in the Angiosperms and Gymnosperms...
August 9, 2017: Canadian Journal of Microbiology
Colleen G Leong, Caroline M Boyd, Kaleb S Roush, Ricardo Tenente, Kristine M Lang, Phoebe Lostroh
Natural transformation is the acquisition of new genetic material via the uptake of exogenous DNA by competent bacteria. Acinetobacter baylyi is model for natural transformation. Here we focus on natural transformation of A. baylyi strain ATCC33305 grown in complex media and seek environmental conditions that appreciably affect transformation efficiency. We find that the transformation efficiency for A. baylyi is a resilient characteristic that remains high under most conditions tested. We do find several distinct conditions that alter natural transformation efficiency including addition of succinate, Fe2+ (ferrous) iron chelation, and substitution of sodium ions with potassium ones...
August 3, 2017: Canadian Journal of Microbiology
Garima Dubey, Bharati Kollah, Usha Ahirwar, Asit Mandal, Jyoti Kumar Thakur, Ashok Kumar Patra, Santosh Ranjan Mohanty
The complex role of phylloplane microorganisms is less understood than the rhizospheric ones in lieu of their pivotal role in plant's sustainability. This experiment aims to study diversity of culturable phylloplane bacteria of Jatropha curcas and evaluate their growth promoting activities towards vigour of maize seedling. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequence of 16S rRNA gene were closely similar to species belonging to the class Bacillales (50%) Gammaproteobacteria (21...
July 31, 2017: Canadian Journal of Microbiology
Conghai Han, Zongli Wang, Guicai Si, Tianzhu Lei, Yanli Yuan, Gengxin Zhang
Large quantities of carbon are stored in the alpine grassland of the Tibetan Plateau (TP), where is extremely sensitive to climate change. However, it remains unclear whether soil organic matter (SOM) in different layers responds to climate change analogously, and whether microbial communities play vital roles in SOM turnover of topsoil. In this study we measured and collected SOM turnover by <sup>14</sup>C method in the alpine grassland to test climatic effects on SOM turnover in soil profiles...
July 25, 2017: Canadian Journal of Microbiology
Xiangyu Guan, Xu Yan, Youxun Li, Bo Jiang, Ximing Luo, Xiaoyuan Chi
Gold tailings often lead to the release of arsenic (As) contaminants into the surrounding environment. Microorganisms play an important role in the As cycle, whereas the effects of As on bacterial communities remain unclear. To reveal the effects of As on diversity and variation of bacterial communities and their As-tolerance potential, farmland soil and river sediment samples were collected according to distance from tailings in Dandong area of northeastern China. The bacterial communities were analyzed using high-throughput sequencing of 16S rRNA genes...
July 12, 2017: Canadian Journal of Microbiology
Paul A Kirchman, Nicholas Van Zee
Individual cells of the budding yeast Saccharomyces cerevisiae have a limited replicative potential, referred to as the replicative lifespan. We have found that both the growth rate and average replicative lifespan of S. cerevisiae cells are greatly increased in the presence of a variety of bacteria. The growth and lifespan effects are not observable when yeast are allowed to ferment glucose but are only notable on solid media when yeast are forced to respire due to the lack of a fermentable carbon source. Growth near strains of Escherichia coli containing deletions of genes needed for the production of compounds used for quorum sensing or for the production of the siderophore enterobactin also still induced the lifespan extension in yeast...
July 5, 2017: Canadian Journal of Microbiology
Shawn Lewenza, Laetitia Charron-Mazenod, Shirin Afroj, Erik van Tilburg Bernardes
Biofilms are dense communities of bacteria enmeshed in a protective extracellular matrix composed mainly of exopolysaccharides, extracellular DNA, proteins, and outer membrane vesicles (OMVs). 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
A Esmaeili Taheri, S Chatterton, B D Gossen, D L 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 3 mismatches to the corresponding binding site of plant pathogens within the genus Aphanomyces. Polymerase chain reaction (PCR) efficiency differs for taxa with uneven primer matching characteristics, which may explain why previous studies have detected this genus at low abundance...
June 2, 2017: Canadian Journal of Microbiology
Arpeeta Ganguly, Rolf D Joerger
The open reading frames SEN0085 and SeKA_A4361, from Salmonella enterica serovar Enteritidis Nal(R) and serovar Kentucky 3795, respectively, corresponding to the acid-inducible sulfatase gene aslA from Salmonella enterica serovar 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...
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 2 unrelated clinical methicillin-resistant Staphylococcus 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 upregulated. With the exception of the downregulation of genes involved with osmotic stress functions, EIS resulted in the upregulation 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 (Brucella melitensis 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 M5-90Δbp26 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 K Guha, Alvan Wai, Georg Hausner
In vitro characterization of 3 LAGLIDADG-type homing endonucleases (HEs) (I-CcaI, I-CcaII, and I-AstI) that belong to the I-OnuI family showed that they are functional HEs that cleave their respective cognate target sites. These endonucleases are encoded within group ID introns and appear to be orthologues that have inserted into 3 different mitochondrial genes: rns, rnl, and cox3. 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
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