Journal of Microbiology / the Microbiological Society of Korea

Poly(β-L-malic acid) (PMA) is a promising polyester formed from L-malate in microbial cells. Malate biosynthesis is crucial for PMA production. Previous studies have shown that the non-oxidative pathway or oxidative pathway (TCA cycle) is the main biosynthetic pathway of malate in most of PMAproducing strains, while the glyoxylate cycle is only a supplementary pathway. In this study, we investigated the effect of exogenous metabolic intermediates and inhibitors of the malate biosynthetic pathway on PMA production by Aureobasidium melanogenum GXZ-6...

Since molecular genotyping has been established for the Candida species, studies have found that a single Candida strain (endemic strain) can persist over a long period of time and results in the spread of nosocomial invasive candidiasis without general characteristics of horizontal transmissions. Our previous study also found the existence of endemic strains in a cancer center in Tianjin, China. In the current study, we performed further investigation on endemic and non-endemic Candida albicans strains, with the aim of explaining the higher morbidity of endemic strains...

A non-motile, yellow-pigmented bacterial strain, designated IMCC34762T , was isolated from a freshwater sample collected from Lake Cheongpyeong in Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain IMCC-34762T formed a lineage within the genus Flavobacterium and was most closely related to F. pectinovorum DSM 6368T (98.3% sequence similarity), followed by F. piscis CCUG 60099T (98.3%), F. branchiicola 59B-3-09T (98.2%), and F. saccharophilum DSM 1811T (98.2%). The average nucleotide identity and the genome-to-genome distance between strain IMCC34762T and the closely related strains were 61-62% and 26-27%, respectively, indicating that IMCC34762T is a novel species of the genus Flavobacterium...

Various Nostoc spp. and related cyanobacteria are able to survive extreme temperatures and are among the most successful colonists of high-elevation sites being exposed due to glacial retreat. It is unclear, however, if cyanobacteria can grow during the extreme freeze-thaw cycles that occur on a yearround basis at high-elevation, peri-glacial sites or if they only grow during the rare periods when freeze-thaw cycles do not occur. We conducted several experiments to determine if cyanobacteria that form biological soil crusts (BSCs) at highelevation sites (> 5,000 m...

Multi-drug resistant (MDR) non-typhoidal Salmonella (NTS) is increasingly common worldwide. While food animals are thought to contribute to the growing antimicrobial resistance (AMR) problem, limited data is documenting this relationship, especially in low and middle-income countries (LMIC). Herein, we aimed to assess the role of non-clinical NTS of bovine origin as reservoirs of AMR genes of human clinical significance. We evaluated the phenotypic and genotypic AMR profiles in a set of 44 bovine-associated NTS...

Streptomycetes naturally produce a variety of secondary metabolites, in the process of physiological differentiation. Streptomyces venezuelae differentiates into spores in liquid media, serving as a good model system for differentiation and a host for exogenous gene expression. Here, we report the growth and differentiation properties of S. venezuelae ATCC-15439 in liquid medium, which produces pikromycin, along with genome-wide gene expression profile. Comparison of growth properties on two media (SPA, MYM) revealed that the stationary phase cell viability rapidly decreased in SPA...

During meiosis, crossing over allows for the exchange of genes between homologous chromosomes, enabling their segregation and leading to genetic variation in the resulting gametes. Spo11, a topoisomerase-like protein expressed in eukaryotes, and diverse accessory factors induce programmed doublestrand breaks (DSBs) to initiate meiotic recombination during the early phase of meiosis after DNA replication. DSBs are further repaired via meiosis-specific homologous recombination. Studies on budding yeast have provided insights into meiosis and genetic recombination and have improved our understanding of higher eukaryotic systems...

Enterococcus faecalis, a Gram-positive bacterium commonly isolated in patients with refractory apical periodontitis, invades dentin tubules easily and forms biofilms. Bacteria in biofilms, which contribute to recurrent and/or chronic inflammatory diseases, are more resistant to antimicrobial agents than planktonic cells and easily avoid phagocytosis. Although Lactobacillus plantarum lipoteichoic acid (Lp.LTA) is associated with biofilm formation, the effect of Lp.LTA on biofilm formation by E. faecalis is not clearly understood...

A Gram-stain-negative, strictly aerobic bacterial strain, designated strain S27T , was isolated from soil near an artificial pond in South Korea. Cells were non-motile short rods showing oxidase- and catalase-positive activities. Growth of strain S27T was observed at 20-40°C (optimum, 30°C), pH 5.0-7.0 (optimum, pH 6.0), and 0-0.5% (w/v) NaCl (optimum, 0%). Ubiquinone-8 was detected as the sole respiratory quinone and the major fatty acids were C16:0 , cyclo-C17:0 , and cyclo-C19:0 ω8c. The G + C content of the genomic DNA was 62...

Arctic tundra ecosystems are rapidly changing due to the amplified effects of global warming within the northern high latitudes. Warming has the potential to increase the thawing of the permafrost and to change the landscape and its geochemical characteristics, as well as terrestrial biota. It is important to investigate microbial processes and community structures, since soil microorganisms play a significant role in decomposing soil organic carbon in the Arctic tundra. In addition, the feedback from tundra ecosystems to climate change, including the emission of greenhouse gases into the atmosphere, is substantially dependent on the compositional and functional changes in the soil microbiome...

Since Salmonella Enteritidis is one of the major foodborne pathogens, on-site applicable rapid detection methods have been required for its control. The purpose of this study was to isolate and purify S. Enteritidis-specific phage (KFS-SE2 phage) from an eel farm and to investigate its feasibility as a novel, efficient, and reliable bio-receptor for its employment. KFS-SE2 phage was successfully isolated at a high concentration of (2.31 ± 0.43) × 1011 PFU/ml, and consisted of an icosahedral head of 65.44 ± 10...

To evaluate the efficacy of a non-adjuvant A/H1N1/2009 influenza A vaccine (GC1115), we demonstrated the immunogenicity and protective efficacy of GC1115 in mouse and ferret models. The immunogenicity of GC1115 was confirmed after intramuscular administration of 1.875, 3.75, 7.5, and 15 μg hemagglutinin antigen (HA) in mice and 7.5, 15, and 30 μg HA in ferrets at 3-week intervals. A single immunization with GC1115 at HA doses > 7.5 μg induced detectable seroconversion in most mice, and all mice given a second dose exhibited high antibody responses in a dose-dependent manner...

Hypocrellin A (HA) is a perylenequinone (PQ) isolated from Shiraia bambusicola that shows antiviral and antitumor activities, but its application is limited by the low production from wild fruiting body. A gene overexpressing method was expected to augment the production rate of HA in S. bambusicola. However, the application of this molecular biology technology in S. bambusicola was impeded by a low genetic transformation efficiency and little genomic information. To enhance the plasmid transformant ratio, the Polyethylene Glycol-mediated transformation system was established and optimized...

Staphylococci have quorum-sensing (QS) systems that enable cell-to-cell communication, as well as the regulation of numerous colonization and virulence factors. The accessory gene regulator (Agr) operon is one of the Staphylococcus genus QS systems. Three groups (I, II, and III) are present in Staphylococcus epidermidis Agr operon. To date, it is unknown whether Agr groups can interact symbiotically during biofilm development. This study analyzed a symbiotic association among Agr groups during biofilm formation in clinical and commensal isolates...

Thermococcus onnurineus NA1, an obligate anaerobic hyperthermophilic archaeon, showed variable oxygen (O2 ) sensitivity depending on the types of substrate employed as an energy source. Unexpectedly, the culture with yeast extract as a sole energy source showed enhanced growth by 2-fold in the presence of O2 . Genome-wide transcriptome analysis revealed the upregulation of several antioxidant-related genes encoding thioredoxin peroxidase (TON_0862), rubrerythrin (TON_0864), rubrerythrin-related protein (TON_0873), NAD(P)H rubredoxin oxidoreductase (TON_0865), or thioredoxin reductase (TON_1603), which can couple the detoxification of reactive oxygen species with the regeneration of NAD(P)+ from NAD(P)H...

A yellow-colored bacterium with gliding motility, strain KIS68-18T , was isolated from a soil sample at Bijin Island in Tongyeong city, Republic of Korea. The cells were strictly aerobic, Gram-staining-negative, non-spore-forming, and rod-shaped. The strain grew at the range of 10-35°C (optimum, 25-30°C), pH 5.5-8.0 (optimum, 6.0-7.5), and 0-0.5% (w/v) NaCl. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain KIS68-18T was closely related to Chryseolinea serpens DSM 24574T (98.9%) and had low sequence similarities (below 92...

Phosphorylation is the most important modification for protein regulation; it controls many signal transduction pathways in all organisms. While several tools to detect phosphorylated proteins have been developed to study a variety of basic cellular processes involving protein phosphorylation, these methods have several limitations. Many proteins exhibit a phosphorylation-dependent electrophoretic mobility shift (PDEMS) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the molecular mechanism responsible for this phenomenon has been elucidated recently...

Since NAD(H)-dependent L-alanine dehydrogenase (EC 1.1.4.1; Ald) was identified as one of the major antigens present in culture filtrates of Mycobacterium tuberculosis, many studies on the enzyme have been conducted. Ald catalyzes the reversible conversion of pyruvate to alanine with concomitant oxidation of NADH to NAD+ and has a homohexameric quaternary structure. Expression of the ald genes was observed to be strongly upregulated in M. tuberculosis and Mycobacterium smegmatis grown in the presence of alanine...

In the article by Kim et al. published in Journal of Microbiology 2015; 53, 805-811, the first sentence of 2nd paragraph in the section of 'Rpd31: The repressor of hyphal induction and the activator of hyphal extension interacting with Ssn6' on page 808 should have read: In C. albicans, there are two proteins as the orthologue of S. cerevisiae Rpd3: Rpd31 (orf19.6801, orf19.14093) and Rpd32 (orf19.2834, orf19.10352) (Hnisz et al., 2009).

Cordyceps militaris is a species of Cordyceps that is classified in the Cordycipitaceae family and is well known in East Asia as a traditional medicinal mushroom. Its artificial fruit body has been widely cultivated for commercial use in cosmetics, functional food, and medicine. To explore the metabolites associated with fruit body development, we conducted gas chromatography mass spectrometry (GC-MS) analyses based on developmental stage, which was divided into the growth period (stage 1, stage 2, and stage 3) and aging period (stage 4)...