Porcine Proliferative Ebterophthy(PPE) is an infectious enteric disease and a major cause of economic loss in swine industry due to weight loss, poor growth and sudden death in growing and finishing pigs at 6 tp 20 weeks of age. PPE has been diagnosed by clinical sighs, syndrom and lesions in the intestine in Korea. However, the diagnostic method had several problems in the detection of infected or carrier pigs. Therefore, in this study, we established the polymerase chain reaction(PCR) which ws a fast, specific and sensitive method for identification of Lawsonia intracellularis(L intracellularis). We designed and synthesized primer on the 16S rDNA and p78 gene encoding L intracellularis. Specificity of the method was confirmed by comparison of the PCR results using other enteric bacteria and the study has shown that PCR method was sensitive to detect 1ng of genomic DNA as a template. Identity of the PCR products was confirmed by comparison of pattern of restriction endonclease analysis with restriction enzyme HaeIII and PstI. Also, the PCR method was applicable to the naturally affected pigs with PPE. Based on the results from this study, the PCR method could be used as a fast and specific diagnostic tool for PPE.

A species-specific 760 base pair(bp) BamHI to EcoRI DNA fragment(fMG-2) of lipoprotein gene was isolated from a Mycoplasma gallisepticum (M gallisepticum) genomic library. Based on the DNA sequence data of fMG-2, a pair of 25bp primers was synthesized. When used in the polymerase chain reaction(PCR), 732bp DNA products were amplified from 6 standard strains and 10 field isolates of M gallisepticum, but not from 2 Mycoplasma synoviae and 7 other Mycoplasma species. The lower detection limit was 100fg of the genomic DNA. Identity of the PCR products was confirmed by comparison of patterns of restriction endonuclease analysis with AseI, DraI, EcoRV and SspI.

Microsatellite allele analysis has been used for individual identification and paternity test. In the present study, the biological father of three puppies was determined by using microsatellite allele amplification analysis. The mother bitch of the litter was a poongsan dog. The three study dogs that could have inseminated the bitch, by being in the same residence, were a white Poosan dog, a mixed breed, and a white Jindo dog. DNA was obtained from all the relevant dogs by buccal swabbing. Four loci of tetranucleotide repeat microsatellite were PCR-amplified, and analyzed by polyacrylamicde gel electrophoresis and silver staining. The results of genotyping unambigously assigned the Poongsan dog as the biological father. There was no evidence of superfecundation. Therefore, the present study demonstrated the usefulness of microsatellite allele analysis as a simple, efficient method of paternity test in dogs.

The visceral dissemination of Borrelia burgdorferi in New Zealand White rabbits was evaluated following intradermal inoculation of 1*10 8 spirochetes. We inoculated Borrelia burgdorferi B31, B garinii KW1 and B afzelii S13, respectively, and monitored the dissemination in the experimentally infected rabbits for 28 days. In the B burgdorferi B31-challenged group, the spirochetes were com;oetely cleared in rabbits at day 1 and visceral dissemination was not demonstrated. However, B garinii KW1 and B afzelii S13 were found to successfully disseminate in visceral organs of rabbits during the experiment period of 28 days. And experimentally infection-derived immunological responses in rabbits were identified with enzyme-linked immunosorbent assay and immunoblot analysis. Based on these results, the differences in the virulence of Lymeborrelial strains were proved in rabbit model.

DNA hybridization assay using probes prepared from liver was carried out to identify species characterization of the domestic animals. Gel electrophoresis showed that the target DNA extracted from raw muscle were 1kb and uniform pattern while fragments size of heated muscle were irrgular. Hybridizatino was performed by adding 200ng/ml probe in hybridization solution and incubating for 12 hours at 68 degrees centigrade. To obtain good discrimination, applied washing buffer and washing step differently depending on the species. The probes of pig, horse and dog formed the specific hybrids with each target DNA respectively. Although cross reaction ws detected in cattle, goat and sheep but signal intensity among these species made the discrimination possible each other. Such pattern was the same in the cases of chicken, turkey and duck. The hybridization pattern of heated muscle was similar to that of raw muscle in general, but the signal intensity was inferior to that of raw muscle. Species identification between closely related animal species, hybridized using the target DNA of such closely related animal species as a blocking agent, remarkable increase of discrimination from the evident decrease of non specific reaction compared with the control group. In addition, in the admixture where certain meat was included in the beef, pork, chicken meat, we colud find whether any unjust meat was admixed or not. In this case, detection limit of certain meat in admixture was 1%.