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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Korean Journal of Microbiology
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Journal DOI :
The Microbiological Society of Korea
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Volume & Issues
Volume 49, Issue 4 - Dec 2013
Volume 49, Issue 3 - Sep 2013
Volume 49, Issue 2 - Jun 2013
Volume 49, Issue 1 - Mar 2013
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Regulation of Activity of the Response Regulator RssB
Park, Hee Jeong ; Bang, Iel Soo ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 215~220
DOI : 10.7845/kjm.2013.3057
Against environmental stresses, many bacteria utilize the alternate sigma factor RpoS that induces transcription of the specific set of genes helpful in promoting bacterial survival. Intracellular levels of RpoS are determined mainly by its turnover through proteolysis of ClpXP protease. Delivery of RpoS to ClpXP strictly requires the adaptor protein RssB. The two-component-type response regulator RssB constantly interacts with RpoS, but diverse environmental changes inhibit this interaction through modification of RssB activity, which increases RpoS levels in bacteria. This review discusses and summarizes recent findings on regulatory factors in RssB-RpoS interactions, including IraD, IraM, IraP anti-adaptor proteins of RssB and phosphorylation of N-terminal receiver domain of RssB. New information shows that the coordinated regulation of RssB activity in controlling RpoS turnover confers efficient bacterial defense against stresses.
The Roles of Immune Regulatory Factors FoxP3, PD-1, and CTLA-4 in Chronic Viral Infection
Cho, Hyosun ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 221~227
DOI : 10.7845/kjm.2013.3049
Human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) cause viral infections that lead to chronic diseases. When they invade human body, virus specific T cells play an important role in antiviral effector functions including killing virus-infected cells and helping B cells to produce specific antibodies against viral proteins. The antiviral activity of T cells is usually affected by immune-regulatory factors that express on surface of T cells. Recently, many researchers have investigated the relationship between effector functions of virus specific T cells and characteristics of immune regulatory factors (e.g., CD28, CD25, CD45RO, FoxP3, PD-1, CTLA-4). In particular, Immune inhibitory molecules such as forkhead box P3 (FoxP3), programmed death-1 (PD-1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) are associated with T-cell dysfunction. They are shown to be up-regulated in chronic viral diseases such as hepatitis B, hepatitis C or human immunodeficiency virus infection. Therefore, the positive correlation between viral persistence and expression of immune regulatory factors (FoxP3, PD-1, and CTLA-4) has been suggested. In this review, the roles of immune regulatory factors FoxP3, PD-1, and CTLA-4 were discussed in chronic viral diseases such as HIV, HBV, or HCV.
Genetic Properties and Antimicrobial Resistance of Campylobacter jejuni Isolates from Diarrhea Patients in Gyeonggi-do
Hur, Eun-Seon ; Park, Po-Hyun ; Kim, Jong-Hwa ; Son, Jong-Sung ; Yun, Hee-Jeong ; Lee, Yea-Eun ; Choi, Yun-Sook ; Yoon, Mi-Hye ; Lee, Jong-Bok ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 228~236
DOI : 10.7845/kjm.2013.3030
Campylobacter jejuni is one of important food-borne pathogens causing human gastroenteritis. We isolated 42 strains of C. jejuni from diarrhea patients and 4 food-poisoning outbreaks in 2010, Gyeonggi-do. In this study, 42 strains were tested for genetic characteristics, the serotype distribution and antimicrobial resistant rate. The presence of hipO (100%), cdtB (100%), and mutated gyrA (95.2%) genes was detected in C. jejuni by polymerase chain reaction (PCR). Detection of mutated gyrA gene correlated with ciprofloxacin resistance. Forty isolates had mutated gyrA gene and were actually resistant to ciprofloxacin. Furthermore, comparing the gyrA DNA sequence data, ciprofloxacin-resistant isolates had a mutation of the DNA sequence from ACA (threonine) to ATA (isoleucine). But 41 strains (97.6%) of patient isolates were susceptible to erythromycin and azithromycin. A total of 35.7% among 42 C. jejuni isolates were identified into 4 different serotypes. The serotype distribution of C. jejuni strains were shown to be HS2(B), HS3(C), HS4(D), HS19(O). To investigate the genotypes of C. jejuni isolated in Gyeonggi province, repetitive sequence polymerase chain reaction (rep-PCR) analysis and SmaI-digested pulsed-filed gel electrophoresis (PFGE) profile analysis were performed. From the PFGE analysis of 42 C. jejuni strains, 12 clusters of PFGE profile were obtained. On the other hand, 11 clusters of rep-PCR profile were obtained from 42 strains of C. jejuni.
Bacterial Diversity in the Guts of Sea Cucumbers (Apostichopus japonicus) and Shrimps (Litopenaeus vannamei) Investigated with Tag-Encoded 454 Pyrosequencing of 16S rRNA Genes
Noh, Eun Soo ; Kim, Young-Sam ; Kim, Dong-Hyun ; Kim, Kyoung-Ho ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 237~244
DOI : 10.7845/kjm.2013.3044
Bacterial diversities in the guts of sea cucumbers (Apostichopus japonicus) and shrimps (Litopenaeus vannamei) were investigated using barcoded or tag-encoded 454 pyrosequencing of 16S rRNA genes. In sea cucumbers, most of sequences were related to two genera, the genus Propionigenium in the phylum Fusobacteria and an unclassified genus in the family Flavobacteriaceae of phylum Bacteroidetes. Shrimps showed various kinds of genera including Lactococcus, Leuconostoc, Prochlorococcus, and Vibrio as well as the unclassified genera in the families, Flavobacteriaceae, Rhodobacteraceae, Desulfobulbaceae, and Helicobacteraceae and in the order Mycoplasmatales. Unclassified genera containing environmental sequences only are more than half of genera from sea cucumbers and shrimps. Sea cucumbers and shrimps could be unexplored sources of novel microbes and the bacterial diversity of them was revealed by high throughput 454 pyrosequencing.
Probiotics with Antimicrobial Activity against Multidrug Resistant Pseudomonas aeruginosa and Acinetobacter baumannii
Lee, Do Kyung ; Kim, Min Ji ; Kang, Joo Yeon ; Park, Jae Eun ; Shin, Hea Soon ; Ha, Nam Joo ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 245~252
DOI : 10.7845/kjm.2013.3048
Pseudomonas aeruginosa and Acinetobacter baumannii are significant opportunistic pathogens in hospitals and are resistant to most antibiotics. Multidrug-resistant P. aeruginosa (MDRPA) and A. baumannii (MDRAB) cause severe human nosocomial infections and are more difficult to treat than methicillin-resistant Staphylococcus aureus (MRSA). Bifidobacteria are among of the most beneficial probiotics and have been widely studied for their antimicrobial activities. The present study explored the antimicrobial activity of Bifidobacterium sp. isolated from healthy Koreans against MDRPA and MDRAB. The antimicrobial activity of the isolates against MDRPA and MDRAB, which are resistant to ciprofloxacin, tobramycin, gentamicin, meropenem, and ceftazidime, was determined by modified broth microdilution methods using absorbance. Among all tested bifidobacteria isolates (nine B. adolescentis, three B. longum, and two B. pseudocatenulatum), the culture supernatant of B. pseudocatenulatum SPM1309 showed a strong growth inhibitory effect against MDRPA and MDRAB. No change in the turbidity of the mixture was observed during incubation, and its inhibitory effect occurred through bacteriostastic action. Moreover, the antibacterial activity was observed in the fraction with molecular weights <10 kDa of bifidobacteria culture supernatant, and the active fraction was heat-stable because it maintained its activity when heated at
for 10 min. The results suggest that this Bifidobacterium strain could have potential applications for alternative therapy in MDRPA and MDRAB infections.
Incubation Conditions and Physico-Chemical Factors Affecting Aflatoxin B
Binding of Lactic Acid Bacteria
Lim, Sung-Mee ; Ahn, Dong-Hyun ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 253~261
DOI : 10.7845/kjm.2013.3050
The purpose of this study was to investigate the aflatoxin
binding of lactic acid bacteria (LAB) isolated from Korean traditional soybean paste and to evaluate the effect of incubation conditions and physico-chemical factors on the binding ability of LAB to this mutagen. The amount of aflatoxin
bound by Enterococcus faecium DJ22, Lactobacillus fermentum DJ35, Lactobacillus rhamnosus DJ42, and Lactobacillus pentosus DJ47 was strain specific with the percent bound ranging from 19.3% to 52.1%. However, Enterococcus faecalis DJ14, Lactobacillus panis DJ29, and Pediococcus halophilus DJ50 strains did not exhibit any of the binding ability to aflatoxin
. For most strains, the binding ability was significantly affected by the environmental conditions such as the aflatoxin
level, incubation time and temperature, and the initial cell count of LAB. The stability of the aflatoxin
-bacteria complexes was significantly more unstable after washing. In addition, the binding stability between viable and nonviable cells was not statistically significant. Treatment with heating, acidic pH,
-amylase, protease, lysozyme, or sodium metaperiodate caused a significant (P<0.05) decrease in aflatoxin
binding for the tested strains, suggesting that carbohydrates or proteins in the cell walls may be involved in aflatoxin
binding ability. Since the aflatoxin
binding of LAB was significantly reduced (P<0.05) by the pretreatment of the urea, the binding force observed in this study may have resulted from hydrophobic interaction.
Fermentation and Quality Characteristics of Cheonggukjang Fermented with Bacillus subtilis BC-P1
Park, Sung-Yong ; Bang, Mi-Ae ; Oh, Boung-Jun ; Park, Jeong-Hoon ; Song, Won-Seob ; Choi, Kyung-Min ; Choung, Eui-Su ; Boo, Hee-Ock ; Cho, Seung-Sik ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 262~269
DOI : 10.7845/kjm.2013.3046
The object of this study was to improve the quality of Cheonggukjang with new starter, Bacillus subtilis BC-P1. Twenty strains were isolated from the commercial cheonggukjang and 1 Bacillus strain (BC-P1) with protease activity was selected. The 16S rRNA gene sequence revealed that the BC-P1 was closely related to B. subtilis with 99% homology. The quality characteristics of chunggukjang fermented with B. subtilis BC-P1, Bacillus nato (PC) and commercial chunggukjang (NC) were investigated. The characteristics of fermentation were determined by protease, lipase, xylanase, chitinase, and fibrinolytic activities, reducing sugar, nutrient composition and amino acid contents of cheonggukjang sample. Cheonggukjang fermented with B. subtilis BC-P1 showed the strongest fibrinolytic, xylanase, and chitinase activities. Reducung sugar contents of Cheonggukjang samples were
mg/g (BC-P1). And their total amino acid contents were 338.99 mg% (NC), 445.19 mg% (PC), 741.35 mg% (BC-P1). These results suggested that B. subtilis BC-P1 was suitable to be used as a starter to enhance the quality and effects of cheonggukjang.
Detection of a Microsporidium, Nosema ceranae, from Field Population of the Bumblebee, Bombus terrestris, via Quantitative Real-Time PCR
Lee, Dae-Weon ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 270~274
DOI : 10.7845/kjm.2013.3052
The bumblebee, Bombus terrestris, has played an important role as one of the alternative pollinators since the outbreak of honeybee collapse disorder. Recently, pathogens and parasites such as viruses, bacteria and mites, which affect the life span and fecundity of their host, have been discovered in B. terristris. In order to detect the microsporidian pathogen, Nosema spp. in the field populations of B. terristris, we collected adults and isolated their genomic DNA for diagnostic PCR. The PCR primers specific for Nosema spp. were newly designed and applied to gene amplification for cloning. Only small subunit ribosomal RNA (SSU rRNA) gene of N. ceranae was successfully amplified among examined genes and sequenced, which indicates that N. ceranae mainly infects the examined field population of B. terristris. To detect of SSU rRNA gene, two regions of SSU rRNA gene were selected by primary PCR analysis and further analyzed in quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis demonstrated that SSU rRNA of N. ceranae was detected at concentration as low as
genomic DNA. This result suggests that the detection via qRT-PCR can be applied for the rapid and sensitive diagnosis of N. ceranae infection in the field population as well as risk assessment of B. terristris.
Dual Coating Improves the Survival of Probiotic Bifidobacterium Strains during Exposure to Simulated Gastro-Intestinal Conditions
Kang, Joo Yeon ; Lee, Do Kyung ; Park, Jae Eun ; Kim, Min Ji ; Lee, Joong-Su ; Seo, Jae-Gu ; Chung, Myung Jun ; Shin, Hea Soon ; Ha, Nam Joo ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 275~281
DOI : 10.7845/kjm.2013.3042
Probiotics have been reported to benefit human health by modulating immunity, lowering cholesterol, improving lactose tolerance, and preventing some cancer. Once ingested, probiotic microorganisms have to survive harsh conditions such as low pH, protease-rich condition, and bile salts during their passage through the gastro-intestinal (GI) tract colonize and proliferate to exert their probiotic effects. The dual coating technology, by which the bacteria are doubly coated with peptides and polysaccharides in consecutive order, was developed to protect the ingested bacteria from the harsh conditions. The aim of the study was to evaluate the viable stability of a doubly coated blend of four species of Bifidobacterium by comparing its bile/acid resistance and heat viability in vitro with that of the non-coated blend. After challenges with acid, bile salts, heat, and viable cell counts (VVCs) of the dual coated and non-coated blend were determined by cultivation on agar plates or flow cytometric measurement after being stain with the BacLigtht kit
. The results showed that the dual coated blend was much higher resistant to the acidic or bile salt condition than the non-coated blend and heat viability was also higher, indicating that the dual coating can improve the survival of probiotic bacteria during their transit through the GI tract after consumption.
Comparison of Bacterial Diversity in the Water Columns of Goseong Deep Seawaters
Khang, Yongho ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 282~285
DOI : 10.7845/kjm.2013.3040
Microbial diversities in the 300 m and 500 m deep seawaters near Goseong, Gangwon Province (South Korea), were investigated. Pyrosequencing of 16S rRNA genes of marine microbes resulted in 19,474 reads from the 300 m deep seawaters, which consisted of Alphaproteobacteria (57.41%) and Gammaproteobacteria (38.85%), and 82,806 reads from the 500 m deep seawaters, which consisted of Gammaproteobacteria (99.64%) mostly. Rhodobacterales (57.31%) were dominant in the 300 m deep seawaters, but Alteromonadales (45.65%) and Oceanospirillales (34.61%) were dominant in the 500 m deep seawaters. On the bases of operational taxonomic units and diversity indexes (Shannon and Simpson), biodiversity of marine bacteria in the 500 m deep seawaters was shown to be higher than that in the 300 m deep seawaters.
Isolation and Identification of Bacillus Strains with Antagonistic Properties against Film-forming Yeasts Overgrown in Low Salted Soybean Pastes
Jeon, SaeBom ; Ryu, MyeongSeon ; Kim, Yong Sang ; Jo, Seung Wha ; Jeong, Do Yeon ; Uhm, Tai-Boong ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 286~291
DOI : 10.7845/kjm.2013.3061
Soybean pastes with 8% (w/w) salinity were prepared instead of soybean paste with 14% (w/w) salinity to meet the growing demands of Korean`s low sodium diet. After aging, white films had appeared on the surface of all low-salted soybean pastes [8% (w/w) salinity] unlike high-salted soybean pastes [14% (w/w) salinity]. All of eight microbes isolated from the surface film were identified as Pichia kudriavzevii. Eleven Bacillus strains with good characteristics of fermentation were isolated from traditionally fermented soybean pastes in order to preserve their unique flavors and aromas after aging, and as a result of analyzing the biochemical characteristics and 16S rRNA sequences, those were identified as B. subtilis, B. licheniformis, and B. methylotrophicus. All of the Bacillus isolates had antagonistic activities against 8 isolates of the film-forming yeasts and harbored the genes for synthesis of antimicrobial surfactants including lichenysin and/or surfactin.
Multiplex Real-Time PCR for Simultaneous Detection of 6 Periodontopathic Bacteria
Cho, Hong-Bum ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 292~296
DOI : 10.7845/kjm.2013.3063
This study utilized an analysis method for detecting six microorganisms, such as Actinobacillus actinomycetemcomitans, Campylobacter rectus, Porphyromonas gingivalis, Tannerella forsythus, Treponema denticola, and Prevotella intermedia, triggering periodontal disease, using multiplex real-time polymerase chain reaction (PCR). The analysis including internal control was made by dividing the six species into two groups using four fluorescence dyes, and it was verified that there was no interference or cross-reaction between the target species and different kinds of oral microbial species. Qualitative and quantitative analyses were conducted on each microorganism in various samples, such as saliva and the plaque, using the multiplex real-time PCR and comparative analysis between periodontitis patients and healthy people, revealing obvious differences between them.
Isolation and Characteristics of Exopolysaccharide Producing Bacteria in a Ginseng Root System
Cho, Geon-Yeong ; Jeon, In-Hwa ; Han, Song-Ih ; Whang, Kyung-Sook ;
The Korean Journal of Microbiology, volume 49, issue 3, 2013, Pages 297~300
DOI : 10.7845/kjm.2013.3059
EPS producing bacteria were enumerated in ginseng root system (rhizosphere soil, rhizoplane, inside of root). EPS producing bacterial density of rhizosphere soil, rhizoplane and inside of root were distributed
CFU/g, respectively. Phylogenetic analysis of the 24 EPS producing isolates based on the 16S rRNA gene sequences, EPS producing isolates from rhizosphere soil (RS) belong to genus Arthrobacter (6 strains) and Rhizobium (1 strain). EPS producing bacteria from rhizoplane (RP) were Arthrobacter (6 strains), Rhodococcus (1 strain) and Pseudomonas (1 strain). EPS producing bacteria from inside of root (IR) were categorized into Rhzobium (6 strains), Bacillus (1 strain), Rhodococcus (1 strain), and Pseudomonas (1 strain). Phylogenetic analysis indicated that Arthrobacter may be a member of representative EPS producing bacteria from ginseng rhizosphere soil and rhizoplane, and Rhizobium is typical EPS producing isolates from inside of ginseng root. The yield of EPS was 10.0 and 4.9 g/L by Rhizobium sp. 1NP2 (KACC 17637) and Arthrobacter sp. 5MP1 (KACC 17636). The purified EPS were analyzed by Bio-LC and glucose, galactose, mannose and glucosamine were detected. The major EPS sugar of these strains was glucose (72.7-84.9%).