• 대한미생물학회지
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• 제35권3호
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• pp.215-224
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• 2000

In this study, the distribution of the mec regulator genes and the presence of the mutation in mecI gene and mec promoter region among 50 MRSA clinical isolates derived from a single university hospital in Korea were analyzed. Among 50 MRSA strains, 13 strains had a deletion of mecI gene, and 37 strains were found to have mutations in mecI gene or mecA promoter region corresponding to a presumptive operator of mecA, i.e., the binding site of the repressor protein. Furthermore, in order to track the evolution of methicillin-resistant Staphylococcus aureus (MRSA) distributed in Korea, we determined the MRSA clonotype by combined use of genetic organization patterns of mec regulator genes, ribotype, and coagulase type. As the result, 48 of 50 MRSA strains could be classified into four distinct clones. Clonotype I is characterized by the coagulase type 3, deletion of mecI gene, and ribotype 1 shared by NCTC10442, the first reported MRSA isolate in England (9 strains). Clonotype II is characterized by the coagulase type 4, C to T substitution at position 202 of mecI gene, and ribotypes 2, 3 and 4 shared by 85/3619 strain isolated in Austria (10 strains). Clonotype III is characterized by the coagulase type 2, mutations of mecA promoter region and/or mecI, and ribotypes 4, 5, and 6 shared by N315 strain isolated in Japan (25 strains). Clonotype IV is characterized by the coagulase type 4, deletion of mecI gene, and ribotype 7 (4 strains). The clonality of two strains could not be determined due to their undefined ribotype.

• Journal of Periodontal and Implant Science
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• 제29권4호
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• pp.963-979
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• 1999

This study examined ribotypes of 36 P. gingivalis strains isolated from 10 rapidly progressive periodontitis patients in Korean and revealed the presence of genetic heterogeneity among the patients. Ribotyping was performed by using a oligonucleotide probes based on 16S rRNA after whole genomic DNA had been digested with the restriction endonuclease enzyme Kpn I and Pst I. In addition, the antigenic heterogeneity of fimbrillin and protease activity was analysed to observe the virulency of P. gingivalis. The results were as follows. 1. Using KpnI, 6 ribotypes were detected, whereas 7 ribotypes were identified by using PstI. When combined two enzymes, a total of 8 ribotypes was subgrouped. 2. Ribotype I/e was the most common and detected in 4 among 10 patients. 3. The fimbrillin expressed from P. gingivalis isolates had the molecular size of 41kDa, 43kDa, 49kDa. It was observed that the size of fimbrillin with the same ribotypes could be identical. 4. All the P. gingivalis strains showed strong proteolytic activity and had the molecular size more than 120kDa. In summary, total 8 ribotypes were observed for isolates from rapidly progressive periodontitis patients. Forty percent of the patients harbored isolates exhibiting the same ribotype I/e, and it was observed that more than one ribotype can coexist in an individual patient.

• 한국해양학회지:바다
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• 제24권3호
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• pp.422-428
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• 2019

어류폐사 와편모조류인 Cochlodinium polykrikoides는 large-subunit(LSU) ribosomal RNA gene을 기반으로 전 세계적으로 4가지 유전타입이 알려져 있으며, 남해안에는 2가지 유전타입이 출현한다고 보고되었다. 본 연구에서는 C. polykrikoides의 동아시아 타입과 필리핀 타입의 남해안 출현양상을 quantitative real-time PCR(qPCR)을 이용하여 3년간(2014~2016년) 조사하였다. 동아시아 타입의 경우 2014~2016년에 40~100% 비율로 남해안 전 정점(통영~완도)에서 검출이 된 반면, 필리핀타입은 대마난류 유입이 강했던 2016년에만 통영~고흥 일부 해역에서 1~2% 비율로 극미량 검출되었다. 위 결과는 동아시아타입이 남해안의 우점 C. polykrikoides 개체군임을 보여주고 있으며, 일부 유영세포는 대마난류를 따라 외해역으로 부터 유입될 수 있음을 시사한다.

• 환경생물
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• 제37권2호
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• pp.119-128
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• 2019

거제도 장목항에서 분리한 Akashiwo sanguinea의 형태와 계통학적 특성을 명확히 하고, 여러 온도와 염분구배에 따른 성장조건을 파악하고자 하였다. A. sanguinea의 세포는 오각형이었고, 세포의 길이는 54.7~70.3 ㎛, 폭은 31.5~48.5 ㎛로 나타났다. 핵은 세포의 중심에 위치하였고, 엽록체는 황갈색으로 세포 전체에 퍼져있었다. 상추구는 알파벳 e 모양이었다. 계통분석 결과 장목항에서 분리한 본 배양주는 ribotype A에 포함되었다. 온도 및 염분구배에 따른 성장 실험은 5℃ 이하의 온도를 제외한 모든 온도구배에서 성장이 나타났다. 그리고, 최대성장속도는 온도 20℃, 염분 20 psu에서 0.50 day^-1로 나타났고, 최대세포밀도는 온도 25℃, 염분 30 psu에서 1,372 cells mL^-1였다. 이 결과는 A. sanguinea가 가을철에 한국 연안에서 최대 증식을 보일 수 있다는 것을 나타낸다.

• Journal of the korean society of oceanography
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• 제39권3호
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• pp.163-171
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• 2004

Sequences of the large subunit ribosomal (LSD) rDNA D1-D2 region of Alexandrium catenella(=A. sp. cf. catenella) and A. tamarense isolates, which were collected along the Korea coasts, were analyzed to understand their phylogenetic relationships and geographical distributions. All A. catenella and A. tamarense isolates belonged to the A. tamarense/catenella/fundyense complex and were grouped with the North American and temperate Asian ribotypes, respectively, regardless of the presence or absence of a ventral pore in the first apical plate. A consistent and peculiar characteristic that differentiated the Alexandrium isolates was amplification of a second PCR product with a lower molecular weight in addition to the predicted one; ten A. catenella isolates belonging to the temperate Asian ribotype yielded this additional PCR product. Sequence alignment revealed that the shorter PCR product resulted from an unusual large deletion of 87 bp in the LSD rDNA D1 domain. The North American and temperate Asian ribotypes were prevalent along the Korean coasts without geographical separation. Given the high genetic homogeneity among widely distributed Alexandrium populations, each ribotype appeared to be pandemic rather than to constitute a distinct regional population.

• 한국축산식품학회지
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• 제40권4호
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• pp.578-587
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• 2020

Clostridioides (Clostridium) difficile is a Gram (+), anaerobic, spore forming, rod shaped bacterium that can produce toxin. The objective of this study is to reveal the presence of C. difficile in meat products, to analyze the ribotype diversity by PCR and to evaluate the antibiotic susceptibility of isolated strains. The organism was isolated in 22 out of 319 (6.9%) examined meat product samples and 9 out of 22 (40.9%) isolates were identified as RT027 and all isolates had the ability of toxin production. In terms of antibiotic susceptibility, all isolates were susceptive to amoxicillin-clavulanic acid, tetracycline and vancomycin and 21 (95.4%) isolates to metronidazole. On the other hand, imipenem and cefotaxim resistance was observed in all. In conclusion, the results of this comprehensive study conducted in Turkey deduced the presence of C. difficile in different meat products. Therefore, these products can be evaluated as a potential contamination source of C. difficile from animals to humans especially for elders, youngsters, long terms wide spectrum antibiotic used and immuno-suppressed individuals.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1146-1155
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• 2008

A total of 72 Bacillus cereus strains and 5 Bacillus thuringiensis strains were analyzed for their EcoRI ribogroup by ribotyping and for the presence or absence of seven virulence-associated genes. From these 77 strains, 42 distinctive ribogroup were identified using EcoRI, but the two species could not be discriminated by their EcoRI ribogroup. The 77 strains were also examined by PCR for the presence of seven virulence-associated genes, cerAB, pi-plc, entFM, bceT, hblA, hblC, and hblD. All five Bacillus thuringiensis strains were positive for these genes. Although differences in the patterns of virulence genes were observed among the different B. cereus strains, within any given ribogroup the patterns of the seven virulence genes was the same. Pulsed-field gel electrophoresis (PFGE) analysis in combination with available chromosomal maps for a selected group of B. cereus strains revealed significant differences in their chromosome size and the placement of virulence genes. Evidence for significant rearrangements within the B. cereus chromosome suggests the mechanism through which the pattern of virulence-associated genes varies. The results suggest linkage between ribogroups and virulence gene patterns as well as no apparent containment of the latter within any particular species boundary.

• Journal of the korean society of oceanography
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• 제39권3호
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• pp.172-185
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• 2004

LSU rDNA D1-D2 and SSU rDNA genes of 23 strains in seven Alexandrium (Halim) species, A. tamarense (Lebour) Balech, A. catenella (Whedon et Kofoid), A. fraterculus (Balech) Balech, A. affine (Inoue et Fukuyo) Balech, A. insuetum Balech, A. pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo and A. tamiyavanichii Balech, were sequenced and the data were used for molecular phylogenetic analysis. The sequence data revealed 11 and 7 ribotypes in the LSU rDNA D1-D2 region and 4 and 17 ribotypes in the SSU rDNA region of A. catenella and A. tamarense, respectively. Other Alexandrium species had also 1 to 5 ribotypes in the two regions. With the exception of CMC2 and CMC3 of A. catenella, all A. tamarense and A. catenella strains had a common ribotype, a functionally expressed rRNA gene (here termed type A), in both gene regions. In addition to the functionally expressed gene, several pseudogenes were obtained that were found to be good tools to analyze the population designation of regional isolates by grouping them according to shared ribotypes. From the phylogenetic analysis of the sequence data determined in this study and retrieved from GenBank, the genus Alexandrium was divided into 14 groups: 1) A. tamarense, 2) A. excavatum, 3) A. catenella, 4) Tasmanian A. tamarense, 5) A. affine (and/or A. concavum), 6) Thai A. tamarense, 7) A. tamiyavanichii, 8) A. fraterculus, 9) A. margalefii, 10) A. andersonii, 11) A. ostenfeldii, 12) A. minutum (or A. lusitanicum), 13) A. insuetum, and 14) A. pseudogonyaulax. The SSU rDNA gene sequence of A. fundyense was so similar to those of A. tamarense used in this study that the two species were difficult to discriminate each other. A. tamiyavanichii was closest to the A. tamarense strain isolated in Thailand and close to the long chain-forming species of A. affine and A. fraterculus. The phylogenetic tree showed that A. margalefii, A. andersonii, A. ostenfeldii, A. minutum and A. insuetum constituted the basal relative complex, and that A. pseudogonyaulax is an ancestral taxon in the genus Alexandrium.