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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...
March 23, 2017: Canadian Journal of Microbiology
Siyuan Chang, Xiaodong Chen, Shuo Jiang, Jinchun Chen, Lin Shi
Biofilm is a biological complex caused by bacteria settlement to the substrates, their subsequent reproduction and secretion. This phenomena reduce heat transfer efficiency and cause significant losses in treated sewage heat recovering systems. This paper describes a physical approach to inhibit the bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant genera in the treated sewage. Here, the micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1 μm to 100 μm) were fabricated as surfaces of interest...
March 23, 2017: Canadian Journal of Microbiology
Yanhong Wang, Na Song, Lina Yang, Heba Abdel-Motaal, Rui Zhang, Zhenglai Zhang, Fankui Meng, Juquan Jiang
In this study, a NhaD-type Na+/H+ antiporter gene designated Ha-nhaD was obtained by selection of genomic DNA from the moderate halophile and alkaliphile Halomonas alkaliphila in Escherichia coli KNabc lacking three major Na+/H+ antiporters. The presence of Ha-NhaD conferred tolerance of E. coli KNabc to up to 0.6 M NaCl and 0.2 M LiCl and an alkaline pH. pH-dependent Na+(Li+)/H+ antiport activity was detected from everted membrane vesicles prepared from E. coli KNabc/pUC-nhaD but not those from KNabc/pUC18...
March 22, 2017: Canadian Journal of Microbiology
Dharmasiri G R S Kulathunga, Joseph E Rubin
The re-emergence of swine dysentery (Brachyspira-associated muco-haemorrhagic colitis) since the late 2000's has illuminated diagnostic challenges associated with this genus. The methods used to detect, identify and characterize Brachyspira from clinical samples have not been standardized and laboratories frequently rely heavily on in-house techniques. Particularly concerning is the lack of standardized methods for determining and interpreting the antimicrobial susceptibility of Brachyspira spp. The integration of laboratory data into a treatment plan is a critical component of prudent antimicrobial usage, the lack of standardized methods is therefore an important limitation to the evidence based use of antimicrobials...
March 21, 2017: Canadian Journal of Microbiology
Laam Li, Sébastien P Faucher
The water-borne Gram-negative bacterium <i>Legionella pneumophila</i> (<i>Lp</i>) is the causative agent of Legionnaires' disease. <i>Lp</i> is typically transmitted to human from water systems, where it grows inside amoebae. Survival of <i>Lp</i> in water is central to its transmission to humans. A transcriptomic study previously identified many genes induced by <i>Lp</i> in water. One of such gene, <i>lpg2524</i>, encodes a putative LuxR family transcriptional regulator...
March 6, 2017: Canadian Journal of Microbiology
Enisa Zanacic, Dena W McMartin, John Stavrinides
Rural communities rely on surface water reservoirs for potable water. Effective removal of chemical contaminants and bacterial pathogens from these reservoirs requires an understanding of the bacterial community diversity that is present. In this study, we carried out a 16S rRNA-based profiling approach to describe the bacterial consortia in the raw surface water entering the water treatment plants of two rural communities. Our results show that source water is dominated by the <i>Proteobacteria</i>, <i>Bacteroidetes</i>, and <i>Cyanobacteria </i>with some evidence of seasonal effects altering the predominant groups at each location...
March 6, 2017: Canadian Journal of Microbiology
Pierre Le Bars, Sebastien Metamoros, Emmanuel Montassier, Françoise Le Vacon, Gilles Potel, Assem Soueidan, Fabienne Jordana, Marie-France De La Cochétière
Many studies show that the human microbiome plays a critical role in the chronic pathologies of obesity, inflammatory bowel diseases, and diabetes. More recently, the interaction between cancer and the microbiome has been highlighted. Most studies have focused on the gut microbiota because it represents the most extensive bacterial community, and the body of evidence correlating it with gut syndromes is increasing. However, in the strict sense, the gastrointestinal (GI) tract begins in the oral cavity, and special attention should be paid to the specific flora of this cavity...
March 3, 2017: Canadian Journal of Microbiology
Zhongmei Liu, Xinxing Gao, Li Zhou, Wenjin Cui, Yaping Tian, Zhemin Zhou
To investigate the physiological role of an extracellular aminopeptidase (BSAP168) encoded by ywaD gene in Bacillus subtilis 168, the ywaD-deletion mutant (BS-AP-K) was constructed. Compared with that of wild-type strain, the maximum growth rate of BS-AP-K was reduced by 28% when grown in soybean protein medium at 37°C, but not in LB medium. The impaired growth rate was more marked at higher temperature and can be compensated by amino acid supplement to the culture media. Further studies showed that there was an obvious difference in the amino acid compositions and peptide distribution in the culture supernatants between the culture supernatants of wild-type and BS-AP-K strains...
March 3, 2017: Canadian Journal of Microbiology
Kari Dunfield, Christopher Yost
No abstract text is available yet for this article.
March 3, 2017: Canadian Journal of Microbiology
Justin P Hawkins, Barney A Geddes, Ivan John Oresnik
In this work the effects of pH on bacterial phenotypes when using the bacteriological dyes Aniline blue, Congo red, and Calcofluor white to analyze polysaccharide production. Study of galactose catabolism in <i>Sinorhizobium melilot</i>i led to the isolation of a mutation in <i>dgok1</i>, which was observed to overproduce exopolysaccharides when grown in the presence of galactose. When this strain was spotted onto plates containing Aniline blue, Congo red, or Calcofluor white, the intensity of the associated staining was strikingly different when compared to the Wild-type...
March 2, 2017: Canadian Journal of Microbiology
Yuan He, Wenge Hu, Decao Ma, Hongzhu Lan, Yang Yang, Yan Gao
Ammonia oxidation is carried out by ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA). The Ebinur Lake wetland is the best example of a temperate arid zone wetland ecosystem in China. Soil samples were collected from rhizosphere and non-rhizosphere soil containing Halocnemum strobilaceum (H and H'), Phragmites australis (R and R'), and Kareliniacaspia (K and K') to study the relationship between environmental factors and the community structure of AOB and AOA. Phylogenetic analysis showed that the AOA sequences belonged to the Nitrosopumilus and Nitrososphaera clusters...
March 1, 2017: Canadian Journal of Microbiology
Natalie Pierrette Blain, Bobbi Helgason, James J Germida
The Bitumount Provincial Historic site is the location of two of the world's first oil extracting and refining operations. Despite hydrocarbons levels ranging from 330 to 24 700 mg kg-1 soil, plants have been able to recolonize the site through means of natural revegetation. This study was designed to achieve a better understanding of the plant root-associated bacterial partnerships occurring within naturally revegetated hydrocarbon contaminated soils. Root endophytic bacterial communities were characterized from representative plant species throughout the site using both high-throughput sequencing and culturing techniques...
February 24, 2017: Canadian Journal of Microbiology
Zoulikha Bouchiba, Zineb Faiza Boukhatem, Zohra Ighilhariz, Nouria Derkaoui, Benaissa Kerdouh, Hanaa Abdelmoumen, Younes Abbas, Mustapha Missbah El Idrissi, Abdelkader Bekki
A total of 51 bacterial strains were isolated from root nodules of Scorpiurus muricatus sampled from six regions of western Algeria. Strains diversity was assessed by rep-PCR amplification fingerprinting which had allowed grouping the isolates into 28 different clusters. Partial Nucleotide sequencing of 16SrRNA gene and BLAST analysis revealed that root nodules of Scorpiurus muricatus were colonized by different species close to Rhizobium vignae, Rhizobium radiobacter, Rhizobium leguminosarum, Phyllobacterium ifriquiensis, Phyllobacterium endophyticum, Starkeya sp...
February 24, 2017: Canadian Journal of Microbiology
Yijun Kang, Yangyang Hao, Dan Xia, Min Shen, Qing Li, Jian Hu
Understanding the dynamics of tetracycline-resistant bacteria (TRB) and tetracycline resistance genes (TRGs) in bulk and rhizosphere soils is important to evaluate the spread of TRGs from pig manure to human. In this work, a greenhouse experiment was conducted to investigate the difference in abundance of TRB, tetracycline-resistant E. coli (TRE), tetracycline-resistant Pseudomonas spp. (TRP), as well as TRGs between bulk and cucumber rhizosphere soils. The application of pig manure resulted in the long-term persistence of TRB, TRE, TRP and TRGs in bulk soil and rhizosphere of cucumber for at least 65 days...
February 21, 2017: Canadian Journal of Microbiology
Michael Ibsen, Dinesh Fernando, Ayush Kumar, Andrea Kirkwood
The alga <i>Cladophora glomerata</i> can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of <i>Cladophora</i>, we investigated the prevalence of antibiotic resistance (ABR) in <i>Cladophora</i>-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities since they receive surface run-off from urban and agricultural sources...
February 13, 2017: Canadian Journal of Microbiology
Tasia Joy Lightly, Ryan R Phung, John L Sorensen, Silvia T Cardona
Phenylacetic acid (PAA), an intermediate of phenylalanine degradation, is emerging as a signal molecule in microbial interactions with the host. In this work, we explore the presence of phenylalanine and PAA catabolism in three microbial pathogens of the cystic fibrosis (CF) lung microbiome: <i>Pseudomonas aeruginosa</i>, <i>Burkholderia cenocepacia</i> and <i>Aspergillus fumigatus</i>. While <i>in silico</i> analysis of <i>B. cenocepacia</i> J2315 and <i>A...
February 8, 2017: Canadian Journal of Microbiology
Rowida Mohamed, Emma Groulx, Stefanie Defilippi, Tamara Erak, James T Tambong, Russell J Tweddell, Apollinaire Tsopmo, Tyler J Avis
Disease suppressive composts have the potential to mitigate the risks associated with chemical pesticides. One of the main characteristics responsible for the suppressive nature of composts is their microbiological populations. In order to gain insight into the determinants responsible for their suppressive effects, composts were assayed (i) to isolate and identify beneficial antagonistic bacteria, (ii) to quantify their antifungal and anti-oomycetal activities, (iii) to extract inhibitory compounds produced by the bacteria, and (iv) to identify antimicrobial lipopeptides produced by these bacteria...
February 8, 2017: Canadian Journal of Microbiology
Yan Long, Changbao Liu, Hengliang Lin, Ningning Li, Qingwei Guo, Shuguang Xie
The present study was to investigate the spatial change of sediment n-damo organisms in mesotrophic freshwater Gaozhou Reservoir (six different sampling locations and two sediment depths (0-5 cm, 5-10 cm)), one of the largest drinking water reservoirs in China. The abundance of sediment n-damo bacteria was quantified using quantitative PCR assay, while the richness, diversity and composition of n-damo pmoA gene sequences were characterized using clone library analysis. The vertical and horizontal changes of sediment n-damo bacterial abundance occurred in Gaozhou Reservoir, with 1...
January 31, 2017: Canadian Journal of Microbiology
Wei He, Jiayi Shu, Jian Zhang, Zhihua Liu, Jianqing Xu, Xia Jin, Xuedong Wang
One of the new HIV vaccine strategies is to design epitope-based immunogen. We previously predicted 20 potential HIV epitopes using bioinformatics approaches. The combination of these 20 epitopes has a theoretical coverage of 98.1% of the population for both the prevalent HIV genotypes and Chinese human leukocyte antigen (HLA) DR types. In order to test whether this vaccine is immunogenic in vivo, a corresponding antigen needs to be prepared. To this end, we constructed recombinant plasmid containing DNA encoding 300 amino acids of this vaccine protein, and then transformed Escherichia coli BL21 (DE3) cells with the plasmid...
January 27, 2017: Canadian Journal of Microbiology
Huizhi Li, Tingting Liang, Qingpo Chu, Feilong Xu, Yuan Li, Lingling Fu, Bo Zhou
To characterize the effects of several subtherapeutic antibiotic combinations on the abundance and diversity of fecal microbes, 400 weaned pigs were selected and randomly assigned to 8 groups, where they were continuously fed different antibiotic combinations for 28 days. Then, a total of 48 pigs were randomly selected to individually collect the feces for DNA extraction and 16S rRNA high-throughput sequencing. Compared with the pigs without antibiotic administration, the diversities of fecal microbes were decreased in the pigs fed chlortetracycline (CTC), olaquindox (OLA) and enramycin (ER)/ virginiamycin (VIR), where the relative abundance of the phymum Bacteroidetes and the genus Prevotella were increased...
January 24, 2017: Canadian Journal of Microbiology
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