• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.487-496
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• 1995

Previous studies have demonstrated that not all A. actinomycetemcomitans produced significant level of leukotoxic factor and its leukotoxicity have associated with serotype and genetic variation. Our aim was to investigate on the interrelationship between serotype and leukotoxicity of an A. actinomycetemcomitans consisting of 13 clinically well characterized. Korean isolates and to evaluate if particular virulent clonal types of A. actinomycetemcomitans are associated with periodontal disease. For this study, 13 strains of A. actinomycetemcomitans from 6 patients with periodontal disease were isolated and identified by using a selective medium(tryptic soy agar supplemented with 10% serum, $75{\mu}g$ of bacitracin and $5{\mu}g$ of vancomycin per ml) in 10% C02 incubator for 3days with routine Gram staining, colony morphology and biochemical test..For serotyping, antisera were prepared from reference strains of 5 serotypes. (ATCC 29523,Y4, SUNY aB 67, IDH 781, IDH 1705) and then ammonium sulfate precipitation, immunoabsorption and indirect immunofluoroscent procedures were done. For analysis of leukotoxicity, sonic extract of A. actinomycetemcomitans exposed to PMN, and trypan blue was stained for counting the cell viability. Finally Southern blot analyses of genomic DNA digested with the restriction enzyme Tag I was done and the Southern blots were hybridized with the 530bp fragment, termed delta 530, originating from the ltx promoter of strain 652 and deleted from strain JP2. Also ltxA-3.1 and SC2 probe from strain JP2 were hybridized with genomic DNA fragments. Results reveal that strains isolated showed approximately equal proportions of 3 serotypes(b, d, e) and serotype b was not detected. 2 patients harbored 2 different serotypes in the same disease site. The prevalence of leukotoxic strain was 23% and there was no relationship between serotype, leukotoxicity and clinical observations. Especially virulent clonal types of Actinobacillus actinomycetemcomitan (JP2 strain) could not found. Further studies are necessary on the genetic polymorphism of leukotoxin and its relations to clinical status.

• 대한수의학회지
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• 제39권4호
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• pp.778-785
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• 1999

To detect CDV RNA in clinical samples and differentiate prevailing CDV virulent strains affecting susceptible animals from attenuated vaccine strains, we performed RT-PCR, RFLP, and sequencing. CDV specific primers were generated from the middle part of nucleocapsid gene. The expected size of PCR products, 519 bp, was observed in tissues of Jindo dog, poodle dog, badger, fourteen of nineteen blood samples as well as 5 vaccine strains including domestic and imported products. The PCR products obtained from tissues and PBMCs of infected animals were digested to 317- and 202-bp fragments by Bam HI, but the products obtained from four of five vaccine strains and Lederle strain were not digesed by Bam HI. Only one vaccine strain of which the PCR products were digested by Bam HI was confirmed as imported vaccine, modified Synider Hill strain. Based on seqencing data obtained from the 519-bp products, it was confirmed that Bam HI restriction site tends to be conserved in field isolates compared to the commercially available attenuated vaccine strains. Partial nucleotide sequences of CDV NP gene obtained from tissues of Jindo dog, poodle and badger shared 100% homology each other, whereas the nucleotide sequences showed 96.3, 96.5, 93.6 and 93.4% homology with Yanaka (virulent), Han95 (virulent), Lederle (attenuated) and Onderstepoort (attenuated) strain, respectively.

• 대한수의학회지
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• 제51권1호
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• pp.37-46
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• 2011

Infectious bursal disease virus (IBDV) is a member of the Avibirnavirus genus of the Birnaviridae family which genome consists of two segments (A and B) of double stranded RNA. Segment A gene of KNU08010 isolate, which was isolated from a 15-day-old chicken flock in 2008, was sequenced and compared with other IBDV isolates including SH/92 strain, the first Korean very virulent (vv) IBDV isolate. The amino acid sequences of segment A gene showed that KNU08010 had 99.2% homology with SH92 strain. KNU08010 isolate had specific amino acids A222, I242, I256, I294 and S299 which are highly conserved among vvIBDV strains. Phylogenetic analysis based on the nucleotide sequences of variable region of the VP2 gene of 18 IBDV strains revealed that KNU08010 was grouped with vvIBDVs and was closely related to Korean vvIBDVs isolated from wild birds.

• 한국미생물·생명공학회지
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• 제18권3호
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• pp.215-220
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• 1990

L.casei YIT 9018균주에 N-methyl-N'-nitro-N-nitrosoguanidine을 처리하여 thermoinducible mutants를 분리하였고, 이 균주를 $42^{\circ}C$에서 30분 동안 열처리하여 prophage가 cured된 균주 L.casei HYM 1213과 L.casei HYM 4024를 분리하였다. Prophage cured strain L.case HYM 1213과 L.casei HYM 4024는 temperate phage $\phi$Fsw에 대해 지시균으로서 능력을 가지고 있었으며, 어떤 온도에서도 temperate phage $\phi$FSW가 검출되지 않았다. 이들의 생리적 특성을 모균주인 L.caseiYIT 9018과 비교한 결과 L.casei HYM 1213 균주는 균의 증식, pH변화, 산생성능력, 당 발효능력에서 모균주와 유사한 것으로 나타났으나, L.casei HYM 4024균주는 pH변화와 산생성능력이 모균주에 비해 미약한 것으로 나타났다. Plasmid DNA는 두 균주 모두 모균주와 동일한 size를 보여주여, prophage가 cured되었어도 plasmid DNA에는 손실을 가져오지 않았음을 알 수 있었다.

• 한국식물병리학회지
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• 제14권6호
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• pp.563-566
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• 1998

Two soybean cultivars, Kwanggyo and Hwanggeum (soybean mosaic potyvirus (SMV)-resistant cultivars), that had been inoculated with a virulent strain (G-5H, 4) of soybean mosaic potyvirus produced necrotic lesions on inoculated leaves as well as on upper trifoliate leaves. Cells in the lesion area contained sparse numbers of virus particles and very few characteristic pinwheel inclusions. Although a hypersensitive-like cellular response occurred in the two resistant cultivars, this response did not prevent the virus from spreading systemically in these resistant hosts, indicating a different mechanism from the general hypersensitive reaction in relation to host resistance.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1228-1235
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• 2011

We compared the gene expression among four clinical and five environmental V. vulnificus isolates, using a cDNA microarray containing 131 genes possibly associated with pathogenicity, transport, signal transduction, and gene regulations in the pathogen. cDNAs from total RNAs of these isolates were hybridized into the cDNA microarray using the cDNA of the wild-type strain MO6-24/O as a reference. We focused on selecting differentially expressed (DE) genes between clinical and environmental isolates using a modified t-statistic. We could detect two statistically significant DE genes between virulent isolates and less-virulent isolates with a marginal statistical significance (p-value of 0.008). These were genes putatively encoding pilin and adenlyate cylase. Real time-PCR confirmed that these two selected genes transcribed in significantly higher levels in virulent isolates than in less-virulent isolates. Mutants with lesions in the gene encoding pilin showed significantly higher $LD_{50}$ values than that of wild type.

• 식물병과 농업
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• 제1권2호
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• pp.22-25
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• 1995

The soybean necrotic disease has been shown to be caused by a virulent strain or strains of soybean mosaic virus (SMV) in soybean cultivar Kwnaggyo. However, the disease was found in soybean cultivar Hwanggeum which was released as a leading and mosaic resistant soybean cultivar in Korea. The strain SMV-G5H appeared to an isolate showing similar characteristics with the strain SMV-G7, although there were some variations in reactions of soybean differentials used.

• 생명과학회지
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• 제24권1호
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• pp.39-45
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• 2014

S. typhimurium MMP13과 ${\chi}8554$는 독력이 약한 JOL401과 독력이 강한 ${\chi}3339$로부터 유래되었다. Heat labile subunit B (LT-B)는 백신의 효율성을 증가시키기 위한 면역보강제로서 일반적으로 사용되고 있다. 고스트 카세트를 운반하는 pMMP184를 MMP13과 ${\chi}8554$에 형질전환하여 고스트를 생성시킨 후 BALB/c 마우스에 근육으로 투여하였다. 면역 보강제가 없는 경우에는 독력에 상반하여 총 IgG 함량이 증가되는 경향성을 보였다. 반대로, 면역보강제를 발현하는 pMMP300을 운반하는 고스트 백신이 동시에 투여되는 경우에는 독력이 강한 균주에서 면역성이 증진되는 경향성을 보였다. 그러나 최종 총 IgG 농도는 유사하게 관찰되었기 때문에, 독력의 세기가 특별히 면역성에 영향을 미치지 못하는 것으로 추정된다. 다른 면역 요소인 IgG1, IgG2a, sIgAs는 특이적인 경향성을 보이지 않았다. 살모넬라 도전실험 결과 독력 유래에 상관없이 유사한 경향성을 보이는 것으로 나타났다. 이상의 결과는 고스트를 생성에 사용된 독력에 관계없이 살모넬라에 대한 면역성이 유발되는 결과를 보였다.

• The Journal of Korean Physical Therapy
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• 제9권1호
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• pp.59-70
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• 1997

The ability of neurotropic alpha herpesviruses to replicate within synaptically linked neurons has made these pathogens valuable tools for transneuronal analysis. Recent studies suggest that unique gene products expressed by genetically engineered strains of virus may permit the use of multiple strains in complex tracing paradigms. In the present study we have examined the invasiveness of two genetically engineered strains of the swine pathogen known as pseudorabies virus(PRV). The two strains were isogenic with the attenuated Bartha strain of PRV; in one strain a lacZ reporter gene was inserted into the gC locus (PRV-BaBlu; $4.75\times10^8pfu/ml$) contrained a PRV envelope glycoprotein gene that was absent in PRV-BaBlu. Simultaneous or temporally separated sequential injection of $4\mu\ell$ of each strain into the ventral wall of the stomach produced a predictale course of retrograde synaptic infection. The results were as follows: 1. PRV-BaBlu and PRV-D infected the dorsal motor nucleus of vagus nerve(DMV) and paraventricular nucleus(PVN). 2. Invasion and replication of PRV-D occured at a faster rate than the parental strain or PRV-BaBlu. 3. PRV-D was much more virulent than PRV-BaBlu or the parental strain. 4. Co-injection of PRV-D and PRV-BaBlu produced an infection that was more virulent than that produced by the parental strain (PRV-Bartha), 5. Neurons in DMV were permissive to co-infection with PRV-D and PRV-BaBlu when they were injected simultaneously into the same site. 6. Replication of PRV-BaBlu was compromised by prior infection of the same circuit with PRV-D. 7. Prior infection of neurons with PRV-D maked them resistant to infection with PRV-BaBlu.

• 대한수의학회지
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• 제8권2호
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• pp.125-146
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• 1968

Throughout the studies the following experimental results were summarized. 1. It was impossible to infect and kill the mice, weighing 10 to 12 gm, by inoculating 0.2ml of virulent Cl. chauvoei, diluted 1 to 10 with physiological saline, via subcutaneous, intramuscular, intraperitoneal or intraveonus, route. 2. The mice which were inoculated in brain with 0.03ml of Cl. chauvoei diluted 1 : 5120 with physiological saline were resulted in all death after infection, but not in case of attenuated strain even in dilution of one to five. 3. Virulent Cl. chauvoei were diluted with each of those of whole blood, erythrocytes and serum of horse, calf, swine, sheep, rabbit, guinea pig, chicken and duck, human plasma and 2% CaCl solution, and inoculated subcutaneously 0.25 to 0.5ml in mice, weighing 12 to 15gm. It was resulted in significant increase in virulence as comparing with the case of physiological saline solution except when horse and pig sera were used. Such a phenomena were not seen in attenuated strain. 4. Virulence of virulent Cl. Chauvoei could be increased significantly in rat, as the procedures used in mice, by suspending in whole blood, erythrocytes, serum, or plasma of various animals, or 2% $CaCl_2$ solution and by inoculating subcutaneously 0.5 to 10ml in rat, weighing 30 to 60 gm, as compared with those of control group which used physiological saline solutionos diluent. 5. Mice resisted 100 and 80 percent against challenge of $10^3$ and $10^4$ M.L.D.. respectively, 24 hours after inoculation of 0.5ml black leg antiserum. 6. Immune response to the black leg living vaccine in mice could be obtained more favorably in the group of respected vaccination rather than those of single inoculation and the most profitable inoculm size of the vacine was 0.5 to 1.0ml. 7. Challenge for the immunized mice could be carried out effectively 3 weeks after first vaccination. 8. Satisfactory results could be obtained by inoculating subcutaneously for the immunization and intracerebrally or subcutaneously for the challenge. 9. Mice which were inoculated with 0.5ml of black leg living vaccine via subtaneucously two times at seven days interval and 21 days after first inoculation and challenged with 5 and 10 M.L.D. of virulent strain, resited 100 and 70 to 80 percent respectively. Same results were obtainable in black leg killed vaccine as the procedures used in living vaccine. 10. There were significantly different resistances against the definite challenge does between the mice groups which were immnuized with the living vaccine diluted five or 10 times and the undiluted. 11. For the biological assay of black leg living vaccine and antiserum, satisfactory results could be obtained using mice.