• 대한수의학회지
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• 제43권2호
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• pp.247-253
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• 2003

Actinobacillus pleuropneumoniae causes a highly contagious pleuropneumoniae in swine. The bacterium produces several virulence factors such as exotoxin, LPS, capsular polysaccharide, etc. Among them, the exotoxin, called Apx, has been focused as the major virulence factor, and the toxin consists of 4 gene cluster. apx CABD. apxA is the structural gene of toxin and has four different types, I, II, III, and IV. As the first step of development of a new subunit vaccine, the three different types of apxA gene were amplified from A. pleuropneumoniae isolated from Korea by PCR with primer designed based on the N- and C-terminal of the toxin. The sizes of apxIA, IIA and IIIA were 3,073, 2,971 and 3,159bps, respectively. The comparison of whole DNA sequences of apxIA, IIA and IIIA genes with those of the reference strain demonstrated 98%, 99% and 98% homology, respectively. In addition, the phylogenetic analysis was performed based on the amino acid sequences compared with 12 different RTX toxin family using the neighbor-joining method. ApxA proteins of Korean isolates were identical with reference strains in this study. All ApxA proteins were expressed in E. coli with pQE expression vector and identified using Western blot with polyclonal antibodies against culture supernatants of A. pleuropneumoniae serotype 2 or 5. The sizes of each expressed ApxA protein were about 120, 110, 125 kDa (M.W.), respectively. The results obtained in this study could be used for the future study to develop a new vaccine to porcine pleuropneumoniae.

• 식물병연구
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• 제14권3호
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• pp.165-170
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• 2008

국내에서 수집한 103 금주의 벼 흰잎마름병 균주를 한국 판별품종과 한 개의 저항성 유전자를 갖고 있는 4개의 준동질 계통에 병원성을 검정하였다. 청청벼, 풍산벼, 한강찰벼, 밀양42호는 저항성 유전자의 배경을 완전히 알 수 없어 벼 흰잎마름병균의 분류에 적합하지 않았다. IRBB101, IRBB103, IRBB105, IRBB107의 계통은 1개의 저항성 유전자를 갖고 있어 벼 흰잎마름병 균주의 레이스를 구분할 수 있었다. 이 계통들은 우리나라 벼 흰잎마름병균의 분류하는 판별품종으로 유용할 것으로 생각된다. 우리나라 벼 흰잎마름병 균주는 4개의 NIL과의 반응에 따라 3개의 레이스로 분류하였다.

• Journal of Microbiology
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• 제38권2호
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• pp.93-98
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• 2000

Nine hundred patients diagnosed with diarrhea or hemorrhagic uremic syndrome in the Kyungpook Province, Korea, were examined from November 1998 to February 2000. One patient in Kumi appeared to possess the Escherichia coli O157:H7 strain, which is very important in clinical decision making and public health action. The isolated strain, an E. coli O157:H7 KM, contained a 60 MDa plasmid and typical virulence genes including the verotoxin 2 gene, ehxA gene (encoding enterohemorrhagic hemolysin), and eae (encoding attaching and effacing protein-intimin) gene. This strain produced only verotoxin 2. Pulsed field gel electrophoretic analysis showed that the genomic organization of the E. coli O157:H7 KM strain may differ greatly from those of representative strains previously reported in the United States and Japan.

• 한국해양바이오학회지
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• 제2권4호
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• pp.263-266
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• 2007

Vibrio vulnificusis a causative agent of serious diseases in humans resulting from the contact of wound with seawater or consumption of raw seafood. Several studies aimed at detecting V. vulnificus have targeted vvh as a representative virulence toxin gene belonging to the bacterium. In this study, we targeted the rpoS gene, a general stress regulator, to detect V. vulnificus. PCR specificity was identified by amplification of 8 V. vulnificus templates and by the loss of a PCR product with 36 non-V. vulnificus strains. The PCR assay had the 273-bp fragment and the sensitivity of 10 pg DNA from V. vulnificus. SYBR Green I-based real-time PCR assay targeting the rpoS gene showed a melting temperature of approximately $84^{\circ}C$ for V. vulnificus strains. The minimum level of detection by real-time PCR was 2 pg of purified genomic DNA, or $10^3$ V. vulnificus cells from pure cultured broth and $10^3$ cells in 1g of oyster tissue homogenates. These data indicate that real-time PCR is a sensitive, species-specific, and rapid method for detecting this bacterium using the rpoS gene in pure cultures and in infected oyster tissues.

• 대한소아치과학회지
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• 제36권4호
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• pp.531-538
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• 2009

본 연구에서는 장기적인 자일리톨의 섭취가 Streptococcus mutans의 대표적인 독성인자 중 하나인 글루칸 생성에 미치는 영향을 알아보기 위하여 글루칸 합성효소인 glucosyltansferase의 mRNA 발현을 실시간 역전사 중합효소 연쇄반응을 통해 평가하여 다음과 같은 결과를 얻었다. 1. 24개월 동안 자일리톨껌을 섭취한 군에서 타액 내 Streptococcus mutans의 colony 수는 통계적으로 유의하게 감소하였다(p<0.05). 2. 비수용성 글루칸 합성에 관여하는 유전자인 gtfB, gtfC의 발현은 자일리톨껌을 섭취한 군에서 시간이 지남에 따라 유의 하게 감소하였다(p<0.05). 특히 gtfB의 발현은 12개월과 24개월째 대조군에 비하여 통계적으로 유의하게 낮았고, gtfC의 발현은 24개월째 대조군에 비하여 통계적으로 유의하게 낮았다(p<0.05). 3. 수용성 글루칸 합성에 관여하는 유전자인 gtfD의 발현 역시 자일리톨껌을 섭취한 군에서 시간이 지남에 따라 유의하게 감소하였다(p<0.05). 또한 gtfD의 발현은 12개월과 24개월째 대조군에 비하여 통계적으로 유의하게 낮았다(p<0.05). 이상의 결과들을 종합해 보았을 때, 자일리톨의 섭취는 구강 내 Streptococcus mutans의 글루칸 합성 관련 유전자들의 발현을 억제시킴으로써 Streptococcus mutans의 수적인 감소를 가져오는 것으로 생각된다.

• 생명과학회지
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• 제34권2호
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• pp.79-85
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• 2024

SlyA는 Salmonella와 같은 장내세균과(Enterobacteriaceae)에 속하는 E. coli에서 용혈소(HlyE)의 발현을 조절하는 전사 조절인자로 알려져 있다. 그러나 Salmonella에는 slyA 유전자가 있지만 hlyE 유전자는 없다. Salmonella에서 SlyA의 역할을 탐구하기 위해 slyA 유전자가 결실된 돌연변이주를 사용하였다. S. Typhimurium CK295 (ΔslyA)는 allelic exchange 방법으로 제작되었다. 야생형 균주와 CK295 균주의 비교시험에서 생육 특성, 운동성, 총 단백질 분석, 분비 단백질 분석 등에서 특별한 차이가 발견되지 않았다. CK295 균주는 야생형에 비해 생물막을 약간 적게 생성하는 패턴을 보였다. 흥미롭게도, 대식세포에서의 생존능력을 비교한 결과, CK295 균주는 야생형에 비해 생존능력이 60% 감소하는 것으로 나타났다. 마우스의 독성을 테스트하기 위해 6주령 BALB/c 마우스에 경구 투여한 후 사망률을 측정하였다. 그 결과, BALB/c에서 CK295 (ΔslyA)의 LD₅₀ 값이 야생형 S. Typhimurium 𝜒3339의 값보다 100배 이상 높게 나타났다. 종합적으로, SlyA는 살모넬라균의 in vivo 생존에 관여하는 독성 인자를 코딩하는 유전자의 발현을 조절하는 것으로 추정된다.

• Mycobiology
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• 제46권4호
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• pp.361-369
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• 2018

The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.

• 한국동물위생학회지
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• 제32권3호
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• pp.227-239
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• 2009

At the present study, it was aimed to detect virulence genes and antimicrobial resistance genes among 102 strains of 12 Salmonella serotypes isolated from pigs and cattle. In polymerase chain reaction (PCR), invA was detected from all strains of Salmonella spp., spvC was detected from Salmonella enterica serotype Enteritidis (S. Enteritidis) (100%), S. Bradenburg (75%), and S. Typhimurium (20.4%). Drug resistance related genes of 12 types were detected from all strains. TEM ($bla_{TEM}$) gene was detected from 51 (92.7%) of 55 $\beta$-lactams (54 ampicillin or 1 amoxicillin) resistance strains. 55 (100%) of 55 chloramphenicol resistance strains, 3 (100%) of 3 gentamicin resistance strains and 5 (100%) of 5 kanamycin resistance strains did contain cml, aadB, and aphA1-Iab, respectively. strB (89.9%), strA (88.4%), aadA2 (84.1%) and aadA1 (72.5%) were detected from 69 streptomycin resistance strains. sulII and dhfrXII were detected from 49 (100%) of 49 sulfamethoxazole/trimethoprim resistance strains, but sulI was not detected. tetA (97.9%) and tetB (21.6%) were detected from 97 tetracycline resistance strains. int gene was detected from 58 (56.9%) of 102 strains. 54 S. Typhimurium of 102 Salmonella spp. were attempted to detect drug resistance genes. TEM was detected from 44 (95.7%) of 46 $\beta$-lactams (45 ampicillin or 1 amoxicillin) resistance strains. cmlA was detected from 51 (100%) of 51 chloramphenicol resistance strains. aadA2 (100%), strA (100%), strB (100%), and aadA1 (79.6%) were detected from 54 streptomycin resistance strains. sulII (100%) and dhfrXII (100%) were detected from 49 sulfamethoxazole/trimethoprim resistance strains. tetA was detected from 54 (100%) of 54 tetracycline resistance strains. int gene was detected from 54 (100%) of 54 strains. The major drug resistance pattern and resistance gene profile were ampicillin, chloramphenicol, streptomycin, sulfamethoxazole/trimethoprim and tetracycline (ACSSuT) and TEM, cmlA, aadA1, aadA2, strA, strB, sulII, dhfrXII, tetA and int, respectively.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.151-152
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• 2002

Bacterial infection is a very complex process in which both pathogenic microorganisms and host cells play crucial roles, and it is the outcome of interactions between the two participants. To elucidate the bacterial pathogenesis mechanisms, therefore, it is essential to understand the cellular and systemic responses of the host as well as the virulence factors of the pathogen. Infection of a host by pathogenic bacteria causes drastic changes in the physiology of host cells, leading to activation of a program of various gene expression. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.174.2-174.2
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• 2003

Quorum sensing, a gene expression in response to population density, is regulated by chemical signals, most of which are acylated homoserine lactones (AHLs). The AHL derivatives have been reported to regulate bioluminescence, virulence factors and / or swarming motility in bacteria. It is hypothesized that higher organisms may have evolved specific means to interfere with bacterial communication as exemplified in the AHL-antagonistic activity of halogenated furanones isolated from the Australian macroalga Delisea pulchra. (omitted)