In the present study, a novel ELISA method used recombinant nucleocapsid protein (rNP) as the coating agent. Recombinant Newcastle disease virus (NDV) protein was cloned and expressed in Escherichia coli. Though the rNP-ELISA results were consistent with commercial ELISA results for the NDV-negative sera samples, qualitatively and quantitatively variable (often reduced) results were obtained with NDV-positive sera. Although the rNP-ELISA results for NDV detection were inconclusive, further improvement and standardization of the rNP-ELISA approach, such as using multiple recombinant proteins as the ELISA coating agent and performing comprehensive statistical analyses of combined recombinant protein ELISA, should help counter Newcastle disease outbreaks by improving NDV detection.

In the current study, 109 commercial nut samples were collected from different Korean markets and analyzed for the contamination of 5 different mycotoxins (aflatoxin, ochratoxin A, deoxynivalenol, zearalenone, and T-2 toxin) using ELISA kits. The results revealed that the most frequently detected mycotoxin was zearalenone (n=36, 33%), followed by aflatoxin (n=31, 28.4%) and ochratoxin A (n=30, 27.5%). Deoxynivalenol and T-2 toxin were also detected in 22 (20.3%) samples, respectively. Among 109 nut samples, 33 samples (30.3%) were contaminated only with one kind of mycotoxin, whereas 43 samples had at least 2 kinds of mycotoxins. Two samples were contaminated with as many as 4 different mycotoxins, and they were both walnuts. Although the monitoring results revealed the amount of aflatoxin contamination was under the safety criteria, there is no current safety guideline for other kinds of mycotoxins or multiple contaminations in Korea. Therefore, further studies should be performed to reveal the distribution of mycotoxin in different foods and propose appropriate safety guidelines for Korean markets.

In this study, two commercial PCR and ELISA test kits were examined for identification of eight animal species (beef, pork, chicken, duck, turkey, goat, lamb, and horse) from raw meat and meat products in Korea. The detection limit in RAW meat ELISA kit® on three types of meat samples blended with beef, pork and chicken, demonstrated that all meat species were differentiable down to 0.2%. RAW meat ELISA kit® on animal species resulted in differentiation rate of 94.5% for beef, 93.3% for pork, 90% for lamb, and 100% for chicken, duck, turkey, goat, and horse. In contrast, Powercheck Animal Species ID PCR kitTM resulted in 100% specificity at 0.05% limit of detection for all meat species. The detection limit of Cooked Meat ELISA kit® on mixed meat samples heat-treated with different temperatures and times, resulted in 0.1% for all heat-treated mixed meat except for chicken at 1.0%. Additionally, ELISA kit on sixty meat products resulted in specificity of 31.8% for ham, 13.6% for sausages, and 12.5% for ground processed products, and relatively low rate for more than 2 types of mixed meats. On the contrary, meat species differentiation using PCR kit showed higher percentage than that using ELISA kit®: 50.0% for ham, 41.7% for sausages, and 28.6% for ground processed meat. Futhermore, PCR kit on 54 dried beef meats detected pork genes in 13 products whereas ELISA kit showed negative results for all products. Hence, the possibility of cross-contamination during manufacturing process was investigated, and it was found that identical tumblers, straining trays, cutters and dryers were used in both beef and pork jerky production line, suggesting the inclusion of pork genes in beef products due to cross-contamination. In this study, PCR and ELISA test kits were found to be excellent methods for meat species differentiation in raw meat and heat-processed mixed meat. However, lower differentiation rate demonstrated in case of meat processed products raised the possibility of inclusion of other species due to cross-contamination during manufacturing process.

Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration 1.0 ng/ml). High progesterone concentration ( 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.

Early diagnoses of pregnancy for animal such as swine and bovine is extremely important to increase income of a farmhouse and for the management of farm. For the development of immunoasaay system of pregnancy in swine, we report a competitive heterologous enzyme linked immunosorbent assay (ELISA) for the direct measurement of oestrone sulfate (E1S) in diluted urine using anti-E1G (glucuronide) monoclonal antibody which cross react with E1S. The principle of assay was based on the typical solid-phase competitive ELISA methods using E1G-HRP (horseradish peroxidase) as a tracer and E1S for standard. The method had a reasonable sensitivity for the detection of E1S with 0.15 ng/ml as a detection limit. The intra-assay and inter-assay precisions were raging coefficient of from 8.50～9.67% and 8.50～9.87%, respectively, which were quite acceptable. In a field trial with a group 37 sows (18 non-pregnancy and 19 pregnancy sows) after day 29～30 post service, the concentration of E1S were determined to be below 30 ng/ml in all non-pregnancy group and over 48 ng/ml in pregnancy group except one sample. The method described here, heterologous ELISA for the measurement of E1S in urine is good enough for monitoring the early pregnancy test of swine.

된장과 고추장에 대해 cdELISA에 AFB_(1)의한 의 분석방법을 확립하고 국내에서 생산되는 재래식 및 개량식 된장과 고추장을 수거하여 AFB_(1)의 오염도를 조사하였다. 표준곡선을 작성하였을 때, 이의 검출 한계는 0.2ng/㎖(ppb)이었다. 된장의 Spike test 후 회수율은 1~100 ng/g 범위에서 평균 71.5%로 나타나 이 범위에서 cdELISA에 의한 AFB_(1)의 측정이 가능함을 보여주었다. 이로부터 된장 및 고추장에서 cdELISA를 통한 AFB_(1)의 분석 방법을 확립하였다. 된장 및 고추장 시료의 AFB_(1)의 오염도는 총 30종의 고추장 시료에서 AFB_(1)이 검출되지 않았고 총 30종의 된장 시료 중 6종에서 1.0~6.0 ng/g 수준으로 검출되었다. 이는 우리 나라의 허용기준인 10 ng/g(ppb) 이하였다.

본 연구는, Vibrio parahaemolyticus에 대한 면역 글로블린 Y(IgY)플 생산하기 위하여 시행되었다. Vibrio parahaemolyticus는 중요한 병원성 균이며. 위장염을 유발시키는 원인 균이다. 따라서, 난황에서 Vibrio parahaemolyticus에 대한 항체를 생산하기 위하여 항원 LPS(lipopolysaccharide)를 암탉에 주사하였다. 면역은 2주 간격으로 4차까지 실시하였으며, 추가면역으로 2주 간격으로 3차 까지 긴시한 후 ELISA로 그 항체 역가를 측정하였다. 난황에서의 항체생성은 1차 면역 후 1주일부터 나타나기 시작하였으며, 7주에 최고 역가에 도달하였고, 이러한 역가는 13주 이후까지 지속되는 것으로 나타났다. 한편 혈청에서의 항체 역가노 난황에서의 경향과 유사하였다. 정제시킨 IgY를 본 연구의 water-dilution 방법과 상업용 IgY분리 kit로 그 정제 정도를 비교해본 결과 큰 차이를 나타내지 않았으며, Vibrio parahaemolyticus외의 다른 Vibrio 속 및 세균들과의 교차반응성 조사에서 특별한 교차반응이 없었다. 본 연구에 나타난 결과로, 아주 적은 양의 LPS 항원으로 역가가 높은 항체의 생산이 가능하였으며, 이러한 결과들을 보아 난황은 유행성 위장염을 유발하는 병원성 균의 특이 항체 개발을 위한 좋은 공급원이 될 것으로 생각된다.

An enzyme-linked immunosorbent assay (ELISA) was established for the detection of zearalenone by using monoclonal antibodies produced by Z-M-26 hybridoma cells when injected into a mouse and zearalenone-oxime-OVA conjugate. Zearalenone-oxime-OVA conjugates were diluted with carbonyl buffer, coated to 96 well microtiter plates at 4℃ overnight and blocked with 1% BSA overnight. One thousand times diluted antibody solution together with standard zearalenone or sample was added to 96-well microtiter plates and stood overnight. A secondary antibody conjugated with HRP was added and an hour later, enzyme substrate (TMBZ) solution was added for color develpment. After 30 minutes, coloring reaction was terminated by adding 2 N H₂SO₄ and the O.D. was measured at 450 nm. Detection range of this method was about 0.1-100 ppb. The established indirect competitive ELISA method was suitable for a rapid and effective analysis of zearalenone in agricultural products.

We have reported a sensitive, specific and simple direct competitive ELISA method to detect aflatoxin in agricultural commodities. We evaluated the ELISA for practical use to detect aflatoxins contaminated in the domestic and foreign agricultural commodities. The detection limits of the direct ELISA for residual aflatoxins in rice, pine nuts, corns, almonds, bean nuts, and pistachio were 10 ppb and in peanuts and cashew nuts were 20 ppb, which were elucidated from the standard curves of ELISA for aflatoxin fortified into the agricultural commodities. Residue studies of naturally contaminated aflatoxins in the agricultural commodities were also carried out by using direct ELISA. As the results of the studies, it was revealed that there were no residues of aflatoxins in 20 rice samples produced in south Korea, 20 pine nut samples in south Korea (9 samples), USA (1 sample) and China (10 samples), each of 20 almond, pistachio and bean nut samples in USA. However, aflatoxin residues were detected in corn samples imported from north Korea (350-585 ppb in 2 of 3 samples), from USA (109-326 ppb in 6 of a samples) and domestic corns (61-326 ppb in 7 of 17 samples). The toxins were contaminated in corn imported from USA for popcorn (17-20 ppb, in 3 of 10 samples) whereas no residues were detected in corn from south Korea and China. In case of cashew nuts imported from India, 11.4-23.1 ppb of aflatoxins were detected in 4 from 20 samples. Most of the contaminated foods were harvested before 1995. Thus, hygienic managements of the foods should be required during storage and circulation at market.

A screening method has been developed for detecting sulfamethazine(SMZ) contamination of meat or feeds by using horseradish pero×idase (HRP) labeled protein A (Prot A-HRP)and an indirect competitive enzyme-linked immunosorbent assay(ELISA). The assay is based on competitive binding of guinea pig anti-SMZ with SMZ in sample and SMZ-gelatin con$lt;jugate(SMZ.GEL) followed by the uptake of prot A-HR,P onto polystyrene microwell plate coated with SMZ.GEL. Percent binding B/Bo × 100) was calculated from the absorbance in the absence (BO) and presence (B) of SMZ. By the sandard curve prepared by plotting log(SMZ) vs percent binding of each lmown reference solution, the detection limit was 1.0 ppb or leas. Cross reaction with sulfadimethoxine, sulfaguaniding, sulfamerazine, sulfamthoaypyridazine, sulfanilamide, aulfisomidine and aulfisoxazole were not observed. But sulfamerazine crosareacted in the test. The EC-50 value (concentration causing 50% inhibition of color development compared with blank) of sulfamerazine was 2.0 ppm. Further quality control will make the ELISA system ideal for the detection of SMZ in meat or feeds.