Canadian Journal of Microbiology

Microorganisms living in soil and rhizosphere or inside plants can promote plant growth and health. Genomic characterization of beneficial microbes could shed light on their special features. Through extensive field survey across Saskatchewan, Canada, followed by in vitro and greenhouse characterization, we identified several bacterial isolates antagonistic to pea root rot pathogen Aphanomyces euteiches . In this study, the genomes of three isolates- Pseudomonas sp. rhizo 66 (PD-S66), Pseudomonas synxantha rhizo 25 (Ps-S25), and Serratia sp...

No abstract text is available yet for this article.

Uropathogenic Escherichia coli (UPEC) is classified as the major causative agent of urinary tract infections (UTIs). UPEC virulence and antibiotic resistance can lead to complications in pregnant women and (or) newborns. Therefore, the aim of this study was to determine the etiological agents of UTIs, as well as to identify genes related to virulence factors in bacteria isolated from pregnant and nonpregnant women. A total of 4506 urine samples were collected from pregnant and nonpregnant women. Urine cultures were performed, and PCR was used to identify phylogroups and virulence-related genes...

The aim of this study was to determine the plant growth promoting effect of Bacillus subtilis PE7 on growth of melon plants. B. subtilis PE7 isolated from kimchi, was identified based on colonial and microscopic morphology along with analyses of 16S rRNA and pycA gene sequences. Strain PE7 showed different levels of inhibition on phytopathogens and was able to grow at variable temperatures and pH values. Strain PE7 had the ability to produce siderophores, indole-3-acetic acid (IAA), ammonia, exopolysaccharides, and 1-aminocyclopropane-1-carboxylic acid deaminase as well as solubilize insoluble phosphate and zinc...

Ribonucleoprotein granules are bio-condensates which form a diverse group of dynamic membrane-less organelles implicated in several cellular functions including stress response and cellular survival. In Toxoplasma gondii, a type of bio-condensates referred to as stress granules (SGs) are formed prior to the parasites' egress from the host cell and are implicated in the survival and invasion competency of extracellular tachyzoites. We used paraformaldehyde to fix and cross-link SG proteins to allow purification by centrifugation and analysis by mass spectrometry...

Biofilms are widely recognized as a prominent mode of microbial growth and strategy of antimicrobial tolerance in many environments. Characteristics that are often overlooked in biofilm investigations include the examination of metabolic pathways as the assumption might be that interference with central pathways such as glycolysis would only reduce growth and thus not be meaningful. Using the Keio collection of Escherichia coli mutants, we investigated the influence of biofilm formation and planktonic growth in full strength and diluted Luria-Bertani (LB) broth using strains with a disruption of glycolysis (Δpgi), the Entner-Doudoroff pathway (Δedd), or the pentose phosphate pathway (Δgnd)...

No abstract text is available yet for this article.

Cold stress is an important factor limiting rice production and distribution. Identifying factors that contribute to cold tolerance in rice is of primary importance. While some plant specific genetic factors involved in cold tolerance have been identified, the role of the rice microbiome remains unexplored. In this study, we evaluated the influence of plant growth promoting bacteria (PGPB) with the ability of phosphate solubilization on rice cold tolerance and survival. To reach this goal, inoculated and uninoculated two-week old seedlings were cold stressed and evaluated for survival and other phenotypes such as electrolyte leakage (EL) and necessary elements for cold tolerance...

Salicylic acids have been used in human and veterinary medicine for their anti-pyretic, anti-inflammatory and analgesic properties for centuries. A key role of salicylic acid-immune modulation in response to microbial infection-was first recognized during studies of their botanical origin. The effects of salicylic acid on bacterial physiology are diverse. In many cases, they impose selective pressures leading to development of cross-resistance to antimicrobial compounds. Initial characterization of these interactions was in Escherichia coli, where salicylic acid activates the multiple antibiotic resistance (mar) operon, resulting in decreased antibiotic susceptibility...

Bacillus cereus endophthalmitis is a devastating eye infection that causes rapid blindness through the release of extracellular tissue-destructive exotoxins. The phagocytic and antibacterial functions of ocular cells are the keys to limiting ocular bacterial infections. In a previous study, we identified a new virulence gene, plcA-2 (different from the original plcA-1 gene), that was strongly associated with the plcA gene of Listeria monocytogenes. This plcA gene had been confirmed to play an important role in phagocytosis...

The genus Robertmurraya was created by my group in 2020 to recognize the contributions of Dr. Robert G.E. Murray to the field of prokaryotic taxonomy. This manuscript updates the information regarding this genus. In addition to the seven Robertmurraya species with validly published names, the work presented here shows that two species with effectively published names, " Bacillus yapensis " and " Bacillus dakarensis ", and an uncharacterized Bacillus sp. Y1 are also affiliated with this genus. Based on these results, reclassification of " Bacillus yapensis " as a novel species Robertmurraya yapensis sp...

Deinococcus murrayi is a bacterium isolated from hot springs in Portugal, and named after Dr. Robert G. E. Murray in recognition of his research on the genus Deinococcus. Like other Deinococcus species, D. murrayi is extremely resistant to ionizing radiation. Repair of massive DNA damage and limitation of oxidative protein damage are two important factors contributing to the robustness of Deinococcus bacteria. Here, we identify, amongst others, the DNA repair and oxidative stress defense proteins in D. murrayi, and highlight special features of D...

In our study, Bacillus subtilis was disposed to a simulated microgravity (SMG) environment in high-aspect ratio rotating-wall vessel bioreactors for 14 days, while the control group was disposed to the same bioreactors in a normal gravity (NG) environment for 14 days. The B. subtilis strain exposed to the SMG (labeled BSS) showed an enhanced growth ability, increased biofilm formation ability, increased sensitivity to ampicillin sulbactam and cefotaxime, and some metabolic alterations compared with the B...

Endophytes confer fitness advantages to host plants. However, the ecological communities of endophytic fungi in the different tissues (rhizomes, stems, and leaves) of Paris polyphylla and the relationship of their endophytic fungi with polyphyllin levels remain unclear. In this study, the community diversity and differences of endophytic fungi in the rhizomes, stems, and leaves of P. polyphylla var. yunnanensis were investigated, and a comprehensively diverse community of endophytic fungi was represented, including 50 genera, 44 families, 30 orders, 12 classes, and 5 phyla...

The surface morphology of mature biofilms is heterogeneous and can be divided into concentric rings wrinkles (I), labyrinthine networks wrinkles (II), radial ridges wrinkles(III) and branches wrinkles (IV), according to surface wrinkle structure and distribution characteristics. Due to the wrinkle structures, channels are formed between the biofilm and substrate and transport nutrients, water, metabolic products, etc. We find that expansion rate variations of biofilms growing on substrates with high and low agar concentration (1...

Acinetobacter baumannii is an opportunistic pathogen known for causing hospital-acquired infections. The natural habitat includes soil, water, sewage, and drains, but it is also detected in infected individuals' blood, pus, and respiratory pathways. Due to its resilient nature, it is known to be a causative agent for outbreaks. Therefore, it is crucial to understand the genetic similarity between clinical and environmental isolates. The study aimed to find the genetic relationships between clinical and environmental isolates using PCR-based typing methods such as enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), random amplified polymorphic DNA (RAPD), and repetitive extragenic palindromic sequence-based PCR (Rep-PCR)...

The rhizosphere is a narrow soil area directly affected by plant root exudates. Microbes inhabiting the rhizosphere have been widely studied for their beneficial effects on plant nutrition, growth, and disease prevention. Many factors affect the rhizosphere microbial composition, including plant pathogen infection. Here, we analyzed the bacterial community structure in the rhizosphere of fungi-infected Amorphophallus titanum. Soil samples were collected from rhizosphere and non-rhizosphere areas of fungi-infected A...

Bifidobacterium and Lactobacillus are known to be common members of the human intestinal microbiota, which plays important roles in maintaining the homeostasis of host gut microenvironment. Several bifidobacterial and lactobacilli strains have been used as probiotics for health benefits. The exopolysaccharides (EPS) produced by strains from Bifidobacterium and Lactobacillus are considered as beneficial traits mediating these beneficial effects. In this study, 21 strains belong to Bifidobacterium and Lactobacillus were isolated from healthy infants' stool and were screened for EPS-producing ability...

The Type VI Secretion System (T6SS) is used by bacteria for virulence, resistance to grazing and competition with other bacteria. We previously demonstrated that the role of the T6SS in interbacterial competition and in resistance to grazing is enhanced in Vibrio cholerae in the presence of subinhibitory concentrations of polymyxin B. Here, we performed a global quantitative proteomic analysis and a targeted transcriptomic analysis of the T6SS known regulators in V. cholerae grown with and without polymyxin B...

The goal of this study was to (a) determine the minimum selection concentrations of tetracycline family antibiotics necessary to maintain plasmids carrying tetracycline-resistant genes and (b) correlate these results to environmental hotspot concentrations reported in previous studies. This study used two plasmids (pT295A and pT413A) originating from dairy manure in a surrogate Escherichia coli host CV601. The minimum selection concentrations of antibiotics tested in nutrient-rich medium were determined as follows: 0...