• Korean Journal of Veterinary Service
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• v.35 no.1
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• pp.9-17
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• 2012

The objective of the present study was to isolate and identify infectious bursal disease viruses (IBDVs) from broiler and layer chickens of outbreaks of infectious bursal disease (IBD) in three districts of Bangladesh. A total of 70 bursal samples were collected from dead broiler (n=40) and layer (n=30) chickens showing specific lesions of IBD from seven commercial poultry farms of three different districts (Mymensingh, Chittagong and Tangail) of Bangladesh during the year 2007. Five representative bursal samples from each farm were used for the isolation of IBDVs using 9-day-old embryonated eggs of seronegative flock of layer birds and for identification the samples were subjected to agar gel immunodiffusion test (AGIDT), immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Out of 35 bursal samples, IBDVs were successfully isolated from 28 (80%) samples. By AGIDT, 32 (91.4%) samples were found positive for IBDV antigen. Results of AGIDT clearly indicated that IBDVs detected in 29 bursal samples of six affected farms were identical to each other but not to IBDVs present in the remaining three samples of another farm. Indirect immunoperoxidase staining of the bursal sections revealed the presence of IBDV antigen in 32 (91.4%) samples and the IBDV antigen was detected mainly in the cortex of the lymphoid follicles of the bursal tissues. In histopathology, cell depletion, atrophy and necrosis were observed in many bursal follicles with severe edema of interfollicular septa. Of the 35 bursal samples, 34 (97.1%) samples generated 254 bp product by RT-PCR. In conclusion, the results of virus isolation and identification by AGIDT, IHC and the analysis of viral genome by RT-PCR confirmed the outbreaks of acute IBD in commercial poultry of Bangladesh. Moreover, histopathological findings and results of AGIDT gave a clear indication that the isolates from six outbreaks were different from classical strain and it seems to be of very virulent strain. On the other hand, the isolates from the other outbreak were similar to the classical strain.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.85-94
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• 1976

Six cases of gangreous mastitis of goats infected spontaneously were observed clinically and pathologically in Daegu and Daejeon district. and with strain isolated purely from the infected goats, the artificial infection to the animal was examined, the sensitivity of strain to the antibiotics was tested and clinical treatment was carried out. The results obtained are summarized as follows: 1. In the six cases approximately same clinical findings were observed as the previously published literatures on gangrenous mastitis of cattle, sheep and goats. 2. The micrococcus pyogenes var aureus was highly virulent strain which was the causative organism for the gangrenous mastitis by inoculating in the udder. 3. The gangrenous mastis was probably occured by the formation of thrombosis in veins of udder. 4. In the sensitivity test, the micrococcus pyogenes var aureus resited for penicillin in 2 cases among the 6 strains, but sensitived for streptomycin, chloromycin, oxyteracycline, erythromycin, achromycin, neomycin and kanamycin in other 4 and in all case. 5. The treatment for gangrenous mastitis may be extirpated the gangrenous region surgically in the case of unilaterally or locally affected, treated by muscle injection or teat-operation in the case of severely or diffusely affected and infused antibiotics up to teat canal or treated by mammary tissue injection in the case of slightly affected.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.82-85
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• 2007

The Chinese medicinal plant Artemisia annua is the source of the antimalarial compound artemisinin. By the way, Artemisin annula was known have endoperoxide ring structure is included and has anti-malarial effect. Malaria and Toxoplasma gondii (T. gondii) is belong to Apicomplexa genera. So, confirmed whether we go compound 1,5-bis(4-methoxyphenyl)-6,7-dioxa-bicyclo[3.2.2]nonane that have endoperoxide ring structure and there is anti-toxoplasmosis effect. The efficacy of 1,5-bis(4-methoxyphenyl)-6,7-dioxa-bicyclo[3.2.2] nonane alone was examined in vitro and in a murine model of acute toxoplasmosis. In vitro studies were peformed with HeLa cell cultures, with quantification of Toxoplasma growth by a cell proliferation assay. Selectivity of 1,5-bis(4-methoxyphenyl)-6,7-dioxa-bicyclo[3.2.2]nonane was 4.9 in vitro cell proliferation assay, this is higher than sulfadiazine (selectivity was 1.63). For in vivo studies, mice were acutely infected intraperitoneally with 10$^5$ tachyzoites of the virulent RH strain and then treated perorally for 4 days from 6 hours postinfection. Efficacy was assessed by sequential determination of parasite burdens in peritoneal cavity. in vitro, 1,5-bis(4-methoxyphenyl)-6,7-dioxa-bicyclo[3.2.2]nonane inhibited Toxoplasma growth at a concentration of 150mg/kg of body weight per day, the inhibition ratio was estimated to be 85.72%.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.213-221
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• 2012

A total of 18 Newcastle disease virus (NDV) isolates that were recovered from 1949 through 1997 were characterized and pathotyped. All viruses were highly virulent as determined by intracerebral pathogenicity indices ${\geq}1.81$ in day-old. These pathotypes are typical for viscerotropic velogenic NDV (VVNDV) pathotype viruses. Some differences were observed for the chicken red blood cell elution rate and thermostability of the hemagglutinin at $56^{\circ}C$. Three antigenic groups were identified by a hemagglutination-inhibition assay using NDV monoclonal antibodies. And the predominant gross lesions were as follows: discharge from the nasal cavity, tracheal mucus, petechial hemorrhage in the heart fat, kidney urates and hemorrhage with or without necrosis in the gastrointestinal tract. Severe hemorrhagic or necrotic lesions were also noted in the lymphoid organs and were localized primarily in the spleen and cecal tonsil. However, differences in the occurrence and frequency of the gross lesions were observed between the virus strains. Among them, NDV strains that induced neurological symptoms belonged only to genotype VI. This strain had spread throughout Korea during the late 1980s to the 1990s, which suggests that specific VVNDVs genotypes might result in neurological symptoms.

• Journal of Plant Biology
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• v.39 no.3
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• pp.179-184
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• 1996

The purpose of this study is to obtain the most efficient combination of Agrobacterium tumefaciens strains and Ti plasmids for the construction of dicotyledonous plant vector system. Ti plasmid-curing A. tumefaciens A136 and KU12C3 were transformed with four kinds of Ti plasmids, pTiBo542, pTiA6, pTiKU12 and pTiAch5, respectively. The stems of 28 species of dicotyledonous plants were then inoculated with these transformants and examined for crown gall formation. The different combination of A. tumefaciens strains and Ti plasmids showed quite a difference in terms of the crown gall formation. Agrobacterium strins A136 and KU12C3 have a same plant host range in case that both strains harour the same kind of Ti plasmid, pTiBo542 or pTiAch5. However, the above-mentioned both strains have quite different host range in the event of containing the same Ti plasmid, pTiKU12 or pTiA6. In case that KU12C3 contains pTiA6 or pTiKU12, this strain has a wider plant host range than A136. The plant host range of pTiBo542 is the widest, followed by pTiA6, pTiKU12 and pTiAch5. Twelve plants among 28 tested plants are not transformed by any virulent Agrobacterium strains used in this study. In conclusion, A. tumefaciens KU12C3 and A136 harboring pTiBo542 showed the widest host range for transforming dicotyledonous plants. Also, it was acertained that the host range of Ti plasmids is affected by chromosomal level.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.321-330
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• 2006

The pathogenic mechanism of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK) by Acanthamoeba has yet to be clarified. Pretense has been recognized to play an important role in the pathogenesis of GAE and AK. In the present study, we have compared specific activity and cytopathic effects (CPE) of purified 33 kDa serine proteinases from Acanthamoeba strains with different degree of virulence (A. healyi OC-3A, A. lugdunensis KA/E2, and A. castelianii Neff). Trophozoites of the 3 strains revealed different degrees of CPE on human corneal epithelial (HCE) cells. The effect was remarkably reduced by adding phenylmethylsulfonylfluoride (PMSF), a serine proteinase inhibitor. This result indicated that PMSF-susceptible proteinase is the main component causing cytopathy to HCE cells by Acanthamoeba. The purified 33 kDa serine proteinase showed strong activity toward HCE cells and extracellular matrix proteins. The purified proteinase from OC-3A, the most virulent strain, demonstrated the highest enzyme activity compared to KA/E2, an ocular isolate, and Neff, a soil isolate. Polyclonal antibodies against the purified 33 kDa serine proteinase inhibit almost completely the proteolytic activity of culture supernatant of Acanthamoeba. In line with these results, the 33 kDa serine proteinase is suggested to play an important role in pathogenesis and to be the main component of virulence factor of Acanthamoeba.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.89-99
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• 2010

Newcastle disease (ND), caused by Newcastle disease virus (NDV), has caused periodic epidemics in Korea at an interval of 3 to 5 years until the early 2000s. At least five distinct genotypes of NDV have been responsible for epizootic episodes in Korea; genotype III virus (before the 1970s), genotype V (the mid-1980s), genotype VI (the late 1980s to early 1990s), genotype VIIa (the mid-1990s), and genotype VIId viruses (the late 1990s to present). Recent epidemic strains of NDV (VIId viruses) shared geographical features with neighboring countries such as China and Japan. These VIId viruses as well as genotypes III and V viruses were viscerotropic and highly virulent for chickens. Antigenic variation occurred between VIId field viruses and LaSota vaccine strain, as found in other epidemic strains in past in Korea. Nevertheless the commercial vaccine was considered to effectively protect vaccinated birds from mortality against VIId viruses as well as other viruses belonging to genotypes III and V.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.73-81
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• 2012

Objectives: With the goal of quantifying the risk of children contracting gastroenteritis while playing at interactive waterscape facilities and evaluating the adequacy of current water quality regulations, risk assessment was performed with Escherichia coli as pathogen. Methods: Abundances of E. coli in the waters of interactive water features in South Korea were acquired from survey reports. A gamma distribution describing the volume of water swallowed by children during swimming activities was adopted. Exposure rate and risk were calculated by Monte Carlo simulation and dose-response models for various pathogenic E. coli. Results: E. coli was detected in 25 out of 40 facilities, with range of ~1,600 CFU/100 ml. The abundance fitted an exponential distribution. Simulated exposures ranged ${\sim}1.9{\times}10^{10}$ CFU, varying greater along E. coli abundance than the volume of water. Risk of children being infected by enterohemorrhagic E. coli was high, with range of ~0.85. When E. coli abundance was <200 CFU/100 ml, which is the current government threshold, the risk decreased to <0.43. Although the guideline successfully reduced the risk of adults being infected by a less virulent E. coli strains (<0.03), the risk for children could not be quantified due to lack of dose-response models for those pathogens for children. Conclusions: Under the current guideline, children are at risk of being infected if water is contaminated with by enterohemorrhagic E. coli. For other E. coli strains, the risk appears to be considerably less. The result warrants need for developing dose-response models for children for each pathogenic E. coli strain.

• Food Science and Preservation
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• v.12 no.2
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• pp.184-189
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• 2005

In order to select probiotics having both a high survival rate and an ability to inhibit virulent pathogens, we have screened lactic acid bacteria and yeasts from Jeot-gal to examine their resistance to artificial gastric and bile juice. After being introduced in the artificial gastric acid for 2 hr, the isolated lactic acid bacteria and yeast were incubated for 24 hrs in the artificial bile juice. In particular, the strain ML 36, ML 128, and ML 178 survived the longest during 2 hr incubation period in the artificial gastric acid. All 3 strains of lactic acid bacteria, and 2 strains of yeast demonstrated higher growth rates than control in the artificial bile. In addition, the antimicrobial activity of lactic acid bacteria and yeasts was investigated to determine their efficiency as probiotic organisms. The lactic acid bacteria inhibited Gram positive and negative bacteria, while the yeast was marginally inhibited.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.343-349
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• 1994

One hundred and two virulent(V) strains of Cryphonectria parasitica were isolated from the cankers of American chestnut (Castanea dentata) trees in western Massachusetts, USA. The diversity of vegetative compatibility groups (VCGs) of C. parasitica was investigated. One hundred and two strains represented 54 VCGs; 38 VCGs had only one strain each, 6 VCGs had 2 strains each, and 10 most common VCGs had 52 strains. Great diversity in VCGs may due to the increasing numbers of VCGs with time since the pathogen has been in Massachusetts for 80 years. Ten vegetative compatibility representative strains were selected from the 10 most common VCGs and converted to hypovirulent (H) strains through the pairing and hyphal anastomosis of H strains (4 strains with French dsRNA elements and 17 strains with Italian dsRNA elements). All of the 10 representative strains were converted to H strains by at least more than one of the H strains.