Demi-embryos were successfully produced by bisection of ICR mouse embryos at preimplantation stages. They were microsurgically bisected using a microsurgical blade attached to a micromanipulator after pretreatment with 0.5 % pronase in PBS for two minutes or not. Embryos with softened zona pellucida were more easily bisected and less damaged than intact embryos. The highest success rate in bisection has been achieved by selecting blastocysts (94.1 % in success rate with intact blastocysts and 100 % in success rate with zona softened blastocysts). Demi-embryos without zona pellucida were cultured in D-PBS or M-16 medium at 37deg C, 5 % CO2 in air for 72 hours for 2-cell stage embryos, 48 hours for 4-to 8-cell stage embryos, 24 hours for morula stage embryos and 6-12 hours for blastocyst stage embryos. For the in vitro culture of 2-cell stage embryos, 100 micro M 2Na-EDTA was added to the media. M-16 medium was better for the in vitro development of mouse embryos than PBS, and PBS is not considered to be suitable for long-term culture of embryos, especially at early stage of cleavage. In M-16 medium, developing rate of demi-embryos of which pair underwent development to form eublastocysts was 15.8 % at 2-cell stage, 16.8 % at 4-cell stage, 38 % at 8-cell stage, 89.6 % at morula stage and 94.4 % at blastocyst stage, respectively. The more rapid and efficient production of demi-embryos and higher viability after bisection can be expected by softening zona pellucida with pronase and by selecting morulae or blastocysts rather than embryos at early stage of cleavage.

The changes in serum total protein and immunoglobulin levels, and BVD, IBR and PI-3 viral neutralizing antibody titers in colostrum-conferred Korean native calves during the first 12 weeks postpartum were studied. The mean concentration of total protein, total immunoglobulin, IgG, IgM and IgA in sera of 9 calves at birth were 3.8 +- 0.5g/dl, 0.27 +- 0.15mg/ml, 0.06 +- 0.08mg/ml, 0.21 +- 0.11mg/ml, and extremely low concentration, respectively. Serum total protein level reached a maximum at 20 hours after birth, total immunoglobulin, IgG and IgM levels at 24 hours, and IgA level at 28 hours, respectively. Serum IgA level reached a minimum at 4 weeks old, IgM level at 5 weeks, total immunoglobulin level at 8 weeks, and IgG level at 10 weeks, respectively. After then those levels had begun to increase, but total protein level was still decreasing at 12 weeks old. The half-lives of IgG, IgM, and IgA were 21.1 days, 4.0 days, and 2.6 days respectively. In 10 Korean native cows immediately after parturition, serum neutralizing antibody titers specific to BVD, IBR and PI-3 virus were 8.7 +- 1.5 log2, 5.7 +-1.2 log2, and 6.8 +- 1.0 log2, respectively. And colostral neutralizing antibody titers against BVD, IBR, and PI-3 virus were 10.1 +- 1.4 log2, 6.8 +- 1.3 log2, and 7.8 +- 1.7 log2, respectively. Before suckling the colostrum, SN antibody titers against BVD, IBR, and PI-3 virus were undetectable from all of 9 Korean native calves. Nevertheless SN antibody titer against BVD virus reached a maximum level (9.2 +- 0.6 log2) at 24 hours after birth, that against IBR virus (6.1 +- 1.0 log2) at 20 hours after birth, and that against PI-3 virus (6.8 +- 0.9 log2) at 32 hours after birth, respectively. In 12 weeks old calves, the SN antibodies against BVD and IBR virus were still decreasing, but that against PI-3 virus reached a minimum at 10 weeks, and increased after 12 weeks of age. The half-lives of SN antibodies against BVD, PI-3 and IBR, virus were 16.0 days, 22.6 days, and 25.5 days, respectively.

This paper deals with the genetic properties of R plasmids in Salmonella originated from pigs and cattle. The plasmid DNA was examined for incompatibility, stability and fertility inhibition (F1), and gel electrophoresis was performed for isolation of plasmid DNA. Among the 66 conjugative R plasmids from 44 pigs and 22 cattle, 61 R plasmids (92.4 %) were Fi-, whereas the remainder were Fi+. The Inc groups of 66 R plasmids were determined with 7 standard plasmids. Twenty-six R plasmids were classified into Inc group Ialpha, H1, H2 or F1, 40 R plasmids being not classified with standard plasmids used, and the Inc group Ialpha (57.7 %) was most frequent. 3. Inc groups Ialpha H1, and F1 were identified in strains from swine, Inc groups H2 and F1 from cattle. The plasmid DNA profiles in 16 Salmonella isolated from pigs and cattle were confirmed as being 1 to 10 fragments by the gel eletrophoresis. Their molecular weight ranged 1.0 to 90 megadalton. The molecular weight of conjugative plasmids ranged 1.0 to 80 megadalton in 4 Salmonella (P-4, P-5, P-7 and P-8) isolated from pigs.

A survey on the prevalence and distribution of antibodies to BLV was performed by the agar-gel immunodiffusion test over a period from 1983 to 1985. More than 2,407 serum samples were collected from Holstein cattle raised in the eastern part of Saitama prefecture where suburban dairy farm is operated. The average positive rate of this period was 4.9 %. The rates of reactive samples varied from 2.6 to 9.8 % among the age groups of cattle from younger than one year to 14 years of age. The positive rate increased gradually with age. The positive rates also varied widely from 0 to 21 % among areas surveyed. Furthermore, there were large differences in this rate among farms even in the same area. The results were interpreted and discussed in connection with the enzootic feature of BLV infection.

This study was performed to investigate the toxicity of ochratoxin A (OA) to the chromosomes of K562 tumor cell-line in vitro. Chromosomes of K562 tumor cell-line resulted in pseudotriploidy on the control group. Chromosomes of K562 tumor cell-line treated with OA resulted in heteroploidy compared with the control group. The mean number of chromosomes in the karyotype of the control group (60) were 7 in the A group, 5 in the B group, 20 in the C+X group, 7 in the D group, 9 in the E group, 6 in the F group, and 6 in the G+Y group respectively. Treating with 0.7 micro M OA, the number of chromosomes were increased one in E and F group, two in G+Y group compared with control group. In treated with 1.5 micro M OA, the increasing number of chromosome was one in E and F group. In treated with 3 micro M OA, E and F group was increased one and G+Y group were increased two chromosome in G+Y group was decreased one. K562 tumor cell line treated with OA showed Philadelphia-Chromosome in the long arm of the G group karyotype chromosome. The rate of chromosome aberration in K562 tumor cell-line treated with OA was 77 % in 0.7 micro M OA group, 71 % in 1.5 micro M OA group, 82 % in 3 micro M OA group and 94 % in 6 micro M OA group respectively. The rate of chromosome aberration of K562 tumor cell-line treated with OA was high in the high dose level of OA, and chromosome aberration of K562 tumor cell-line treated with OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype. As a result of this study, the toxicity of OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype, and then, the toxicity of OA resulted in the damage to RNA and protein synthesis in K562 tumor cell-line, and the C-group karyotype of K562 tumor cell-line was target of the toxicity of OA.

In order to study the marked variation of red blood cell sedimentation rate in some species of animals, the packed cell volume, volume percentage of erythrocytes in whole blood, was reshuffled of 20%, 40% and 60% using heteroplasma of chicken and goat, and the red blood cell sedimentation rate was measured in Westergren tubes at 27+-1 deg C and 8+-1 deg C. The values of packed cell volume (PCV) of goat and chicken were 40.7+-4.1% and 30.2+-2.2% respectively. The sedimentation rates of reshuffled red blood cell were settled faster at lower PCV than higher PCV, i.e. there was a reverse relationship between the sedimention rate and PCV. Red blood cells of chicken settled quickly, where as those of goat settled very slowly. Chicken red blood cell sedimented rapidly even in goat plasma, and goat red blood cell sedimented slowly in chicken plasma. These findings indicate that the plasma is not the only factor determining the rapid red blood cell sedimentation rate of chicken. The sedimentation rate of reshuffled red blood cell of chicken and goat were accelerated at higher temperature than lower temperature.

This paper deals with the distribution of Salmonella (S) infection on 4 herds in Kyungju and Taegu during the period from May to October 1986. Isolated Salmonella were examined for serotypes, antimicrobial drug resistance and detection of R plasmid. From 4 herds, 67 Salmonella were isolated from 51 samples (1.1%), and their serovar strains were S. typhimurium 6, S. derby 5, S. infantis 4, S. bareilly 4, S. dublin 3, S. anatum 2, S. montevideo 2 and untypable 41. In 4 herds, the incidence of drug resistance was 57.7-100% and transfer frequency of conjugative R plasmid was 96.1-100%.

The anatomical structure of pelvic limb of thirty-one adult Korean native goats (Body weight : 14-17kg) was observed after skeletal preparation, and the osteometry was performed in each bone. The pelvic limb of the Korean native goat was composed of the hip bone, femur, patella, tibia, fibula, tarsal bones, metatarsal bone, phalanges and sesamoid bones. The hip bone consisted of the ilium, ischium and pubis which fused each other. The gluteal surface of the ilium was directed dorsolaterally. The tuber sacrale and tuber coxae were formed at the dorsal apex and ventrolateral part of the iliac wing, respectively. The lesser ischiatic notch was deeper than the greater one. The ischiatic tubercles were triangular and consisted of the dorsal, lateral and caudal ischiatic tubercles. The left and right hip bone indexes were 67.08, 66.20, the acetabular indexes were 93.78 and 92.10 and the obturator formen indexes were 53.84 and 54.77, respectively. In femur, both of the greater and lesser trochanter were well developed but the third trochanter was not observed. The left and right femur indexes were 26.55 and 26.14, head indexes were 81.66 and 81.49 and the trochlear-epicondyle indexes were 42.47 and 41.63, respectively. The patella was observed as an isosceles triangle with base lying proximal and the cranial surface was more convex. The tibial shaft was sigmoid (S-) shaped and the popliteal notch was deep. There was a large nutrient formen at the cranial aspect of the cranial intercondylar area. The tibial indexes were 22.09 (left) and 21.10 (right). The proximal extremity of the fibula was fused with the lateral condyle of the tibial but the distal one was observed independently as the malleolar bone.