• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.69-73
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• 1989

Nine strains of Yersinia species isolated from pigs and dogs in Korea, comprising 5 strains of Yersinia enterocolitica, 2 strains of Y kristensenii and each strain of Y pseudotuberculosis and Y intermedia, were examined for the presence of virulence-associated plasmids, calcium dependency and provocation of guinea pig conjuntivitis($Ser{\acute{e}}ny$ test). Three strains of Y enterocolitica isolated from pigs were positive in calcium dependency and harbored one plasmid of about 45 megadalton, but negative in $Ser{\acute{e}}ny$ test.

• Journal of Microbiology
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• v.38 no.3
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• pp.117-121
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• 2000

Recent advances in studies of bacterial gene expression and light microscopy show that cell-to cell communication and communication and community behavior are the rule rather than the exception. One type of cell-cell communication, quorum sensing in Gram-negative bacteria involves acyl-homoserine lactone signals. This type of quorum sension represents a dedicated communication system that enables a given species to sense when it has reached a critical population density. and to respond by activating expression of specific genes. The LuxR and LuxI proteins of Vibrio fisheri are the founding members of the acyl-homoserine lactone quorum sensing signal receptor and signal generator families of proteins. Acyl-homeserine lactone signaling in Pseudomonas aeruginosa is one model for the relationship between quorum sensing community behavior, and virulence. In the P. aeruginosa model. quorum sensing is required for normal biofilm maturation and virulence. There are multiple quorum-sensing circuits that control the expression of dozens of specific genes in P. aeruginosa.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.104-108
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• 1990

The chromosomal DNA of Agrobacterium tumefaciens contains the genes required for bacterial attachment to plant cell which is an essential atage in crown gall tumorigenesis by Ti-plasmid. In order to clone the genes, Agrobacterium tumefaciens strain A5512 was mutagenized by transposon Tn5 and two Agrobacterium tumefaciens mutants which are attachment-defective and nontumorigenic were isolated. From one of the two mutants, a chromosomal virulence region which was required for attachment to the plant cells was cloned.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.219-222
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• 2007

A total of the 261 Phytophthora infestans isolates collected from 2003 to 2005 in Korea were investigated for their physiological race composition. Among the isolates, we detected 18 physiological races and the dominant races were R0.1.3.5.6.10.11 and R0.1.3.5.6.7.10.11 with frequencies of 18.4% and 11.4%, respectively. All of the P. infestans races carried multiple virulence genes and showed virulence to the potato resistance genes R1, R3, R5, R6, R7, R10 and R11, but not to R8 and R9. Therefore, it is likely that the physiological races of P. infestans were diverse in Korea.

• Mycobiology
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• v.39 no.3
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• pp.143-150
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• 2011

The basidiomycete fungus Cryptococcus neoformans is an important pathogen of immunocompromised people. The ability of the fungus to sense its environment is critical for proliferation and the generation of infectious propagules, as well as for adaptation to the mammalian host during infection. The conserved cAMP/protein kinase A pathway makes an important contribution to sensing, as demonstrated by the phenotypes of mutants with pathway defects. These phenotypes include loss of the ability to mate and to elaborate the key virulence factors capsule and melanin. This review summarizes recent work that reveals new targets of the pathway, new phenotypic consequences of signaling defects, and a more detailed understanding of connections with other aspects of cryptococcal biology including iron regulation, pH sensing, and stress.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1343-1347
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• 2016

Outer membrane vesicles (OMVs) are spherical nanostructures that are ubiquitously shed from gram-negative bacteria both in vitro and in vivo. Recent findings revealed that OMVs, which contain diverse components derived from the parent bacterium, play an important role in communication with neighboring bacteria and the environment. Furthermore, nanoscale proteoliposomes decorated with pathogen-associated molecules attract considerable attention as a non-replicative carrier for vaccines and drug materials. This review introduces recent advances in OMV biogenesis and discusses the roles of OMVs in the context of bacterial communication and virulence regulation. It also describes the remarkable accomplishments in OMV engineering for diverse therapeutic applications.

• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.395-401
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• 1996

국내의 고추, 사과, 포도, 스타티스(statice)에서 분리한 Glomerella cingulata 균주들의 병원성과 체세포화 합성군(vegetative compatibility group : VCG)과의 관계를 조사하였다. 사과, 포도, 스타티스에서 분리된 균주들은 전기주에 모드 병원성을 나타내었으나 고추에는 병원성이 없었다. 한편, 고추에서 분리된 균주들은 무상처접종시 병원성을 나타내지 못하였다. Nitrate nonutilizing(nit) mutant는 1.5%의 KClO\ulcorner을 첨가한 최소배지에서 선발하였다. nit mutnat들은 nit1, nit2, nit3, nitM의 4가지 표현형 중 하나에 속하였다. VCG는 표현형이 다른 nit mutan간의 대치배양을 통해 결정하였는데 사과, 포도, 스타티스에서 분리한 균주들간에는 같은 VCG를 나타낸 반면 고추에서 분리된 균주들은 다른 VCG로 나타났다. 따라서 G. cingulata 균주들의 체세포화합성은 병원성과 밀접하게 관련되어 있음을 알수 있었다. 또한 동일한 VCG에 속하며 기주가 다른 균주들의 대치배양시 heterokaryon을 형성했으나 자낭을 형성하지는 않았다.

• Journal of Microbiology
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• v.43 no.5
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• pp.443-450
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• 2005

The multi-host pathogen, Pseudomonas aeruginosa, possesses an extraordinary versatility which makes it capable of surviving the adverse conditions provided by environmental, host, and, presumably, competing microbial factors in its natural habitats. Here, we investigated the P. aeruginosa-Bacillus subtilis interaction in laboratory conditions and found that some P. aeruginosa strains can outcompete B. subtilis in mixed planktonic cultures. This is accompanied by the loss of B. subtilis viability. The bactericidal activity of P. aeruginosa is measured on B. subtilis plate cultures. The bactericidal activity is attenuated in pqsA, mvfR, lasR, pilB, gacA, dsbA, rpoS, and phnAB mutants. These results suggest that P. aeruginosa utilizes a subset of conserved virulence pathways in order to survive the conditions provided by its bacterial neighbors.

• Infection and chemotherapy
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• v.50 no.4
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• pp.340-345
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• 2018

Frequent isolation of Enterococcus faecalis from root canal treated teeth with apical periodontitis, has proposed the role of this organism in endodontic treatment failures. Different factors have been suggested in the pathogenicity of this organism. In this study, 22 E. faecalis isolates from canals of root-filled teeth were identified, and phenotypic and genotypic characteristics were investigated. No resistance to vancomycin and gentamicin was noted, and most isolates (91%) were susceptible to ampicillin. Biofilm formation was detected in 73% of the isolates and may be considered as the most important virulence factor involved in the pathogenesis of these isolates.

• Korean Journal of Veterinary Research
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• v.63 no.2
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• pp.16.1-16.6
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• 2023

Salmonella spp. are pathogens involved in most salmonellosis in rabbits. This study examined Salmonella disease in rabbits raised in Thua Thien Hue, Vietnam. Two hundred and 56 rectal swabs of rabbits were taken, and a carrier rate of 33.98% was found. In addition, all the isolated Salmonella spp. strains were 100% motile; positive for H₂S, catalase, Voges Proskauer, coagulase, citrate, maltose, and dextrose; and negative for indole, methyl red, urease, oxidase, sucrose, and lactose. The Kirby-Bauer method showed that these Salmonella strains were susceptible to doxycycline (93.2%), tetracycline (84.1%), and levofloxacin (65.9%). On the other hand, they were highly resistant to streptomycin (95.5%), ampicillin (93.2%), colistin (40.9%), and gentamicin (34.1%). Furthermore, polymerase chain reaction used to screen for virulence and specific genes of Salmonella strains showed that all Salmonella strains isolated carried InvA, fimA, and Stn.