Genotype x environment interaction effects on carcass traits in Japanese Black cattle

The importance of genotype x environment (region or management system) interactions for carcass traits in Japanese Black cattle was investigated using both univariate and multivariate animal models. The univariate approach was used mainly to test the significance of interaction effects. The multivariate approach was used to estimate genetic correlations, which indicated the magnitude of genotype x environment (GE) interactions. The more a genetic correlation deviates from 1, the larger the interaction. From the univariate approach, the addition of genotype x environment (region or management system) interaction (co)variance components resulted in an improved fit of the model for all traits in both cases (P < 0.001). However, estimates of genetic correlation between regions obtained from the multivariate approach for hot carcass weight, LM area, rib thickness, s.c. fat thickness, and marbling score were 0.97, 0.95, 0.93, 0.97, and 0.93, respectively. The corresponding estimates between management systems were 0.84, 0.92, 0.84, 0.90, and 0.97, respectively. These results indicate that GE interaction effects on carcass traits of Japanese Black cattle may be biologically unimportant. Therefore, breeding values obtained using the multivariate method would rank sires similarly in all environments. Consequently, carcass traits measured in these two different regions or management systems can be treated as the same traits.     

Follicular and hormonal dynamics during the estrous cycle in goats

Transrectal ultrasonography of ovaries was performed daily in 6 goats for 3 consecutive estrous cycles. Blood samples collected daily were measured for concentrations of FSH, inhibin A, and estradiol-17beta. Follicular and hormonal data were analyzed for associations between the follicular waves and hormonal concentrations. During the interovulatory intervals, follicular growth and regression occurred in a wave like pattern (2-5 waves), and the predominant patterns were three and four follicular waves. In addition, there was no significant difference among the diameters of dominant follicles during the growth phase of the follicular waves. The number of 3 mm follicles peaked on days 0, 7, and 11 in interovulatory intervals that had three follicular waves and on days -1, 5, 11, and 15 in those that had four follicular waves. Plasma concentrations of FSH increased around the day of follicular wave emergence and declined with the growth of follicles. Circulating FSH increased again concomitant with regression of dominant follicles in the anovulatory wave, whereas FSH levels remained low in the ovulatory wave. Inhibin A was negatively correlated with FSH, while it was positively correlated with estradiol-17beta, suggesting that inhibin A is a product of healthy growing follicles and that it contributes to the suppression of FSH secretion. In conclusion, the growth of ovarian follicles in goats exhibits a wave-like pattern, and follicular dominance is less apparent in goats. Moreover, inhibin A may be a key hormone for regulation of the follicular wave through suppression of FSH secretion in goats.     

A novel method for estimating the adaptive ability of guide dogs using salivary sIgA

Salivary secretory immunoglobulin A (sIgA) concentrations of prospective guide dogs for the blind were determined to clarify whether salivary sIgA is useful in evaluating the potential suitability of guide dogs for the blind. Saliva was collected from 73 prospective guide dogs in the kennel on day 1 (the day of separation from volunteer puppy-raisers), 2, 3, 7 and 14 during the estimation period (at about 1 year old). We selected particularly suitable dogs (superior dogs) and unsuitable dogs (inferior dogs) on the basis of the trainers' estimation. All dogs were divided into two groups, those were acceptable dogs would become the guide dogs and rejected dogs could not become guide dogs. The sIgA concentrations in superior dogs gradually increased from day 1 to 14 and those in inferior dogs remained at low levels. Moreover, the sIgA concentrations on day 14 in the acceptable dogs were significantly higher than those in rejected dogs. The cut-off point of sIgA concentrations on day 14 using an ROC curve was 90 EU/ml, and the specificity of the estimation at this point (70.4%) was higher than that of trainers' estimation (50%). Moreover, parallel testing using both trainers' estimation and sIgA estimation, showed that specificity was further improved (79.5%). The present study showed that sIgA concentration was extremely useful in estimating the adaptive ability for guide dogs for the blind.     

Establishment and characterization of eight feline mammary adenocarcinoma cell lines

Eight new feline mammary adenocarcinoma cell lines derived from either primary or metastatic lesions were established. The morphology of all the cell lines was epithelioid and round to spindle in shape, with cell growth occurring in a monolayer fashion. On immunohistochemistry, these cells reacted with anti-keratin and anti-vimentin antisera. The doubling time of these cells was between 19 and 54 hr. Tumor masses were developed in nude mice by subcutaneous inoculation of the cells that were histologically identical to their original mammary tumor lesions. Telomerase activities measured using the telomeric repeat amplification protocol assay revealed high telemetric activity in all of the cells.     

Characteristics of Staphylococcus aureus isolated from lesions of horses.

Seventy-six Staphylococcus aureus strains isolated from various lesions of horses were characterized. All of the 76 strains were identified as biotypes B (38.2%) and C (61.8%). Of 55 strains tested, 42 (76.4%) were differentiated into 7 coagulase types. Coagulase types V and VII were predominant in the metritis strains. Coagulase type II was found most frequently in the strains from phlegmon, dermatitis, sinusitis, empyema sinus, and nasal catarrh. Forty-two (55.3%) of the 76 strains were differentiated into 24 phage patterns. Twenty (58.8%) of 34 typable strains from metritis were lysed by the human group I phage 52, and group II phages 3A, 3C, 55 and 71. Forty-five (59.2%) of the 76 strains were resistant to 1 or more of 6 antibiotics. Strains resistant to penicillin G, irrespective of source, were most frequent (95.6%). Forty (93.0%) of 43 strains resistant to penicillin G alone or in combination with other antibiotics produced beta-lactamase. Only 8 (10.5%) of the 76 strains produced enterotoxins A (n = 2), B (n = 1) or C (n = 5), and they all were isolated from metritis. Only 1 strain isolated from phlegmon and 2 from metritis produced exfoliative toxin (ET) and toxic shock syndrome toxin-1 (TSST-1), respectively. The latter 2 strains also produced enterotoxin C. The results of the present study showed the first evidence of the presence of both ET- and TSST-1-producing S. aureus isolated from horses.     

Immunohistochemical localization of steroidogenic enzymes in corpus luteum of wild sika deer during early mating season

We analyzed the localization of steroidogenic enzymes (P450 scc, 3 beta HSD, P450 arom and P450 c17) in the corpora lutea of two Hokkaido sika deer (Cervus nippon yesoensis) during the early mating season. Two corpora lutea were found in each female and the timing of formation of the corpora lutea seemed different. P450 scc, and 3 beta HSD, positive luteal cells were found in both corpora lutea. The existence of two functional corpora lutea from the early mating season through pregnancy suggests that progesterone secreted by two or more corpora lutea is necessary for maintenance of pregnancy in sika deer.     

Exon skipping of exonuclease 1 in MRL/MpJ mice is caused by a nucleotide substitution of the branchpoint sequence in intron eight

In MRL/MpJ mice, there is a genetic mutation of exonuclease 1 (Exo1), in which the exon 9 is sometimes deleted. In the present study, to check the generation of the spliced exons, exon 8-intron 8-exon 9 (pCX/Ex/EIE/B and pCX/Ex/EIE/M) plasmids were temporally transfected in vitro into BALB 3T3 cells, and RT-PCR using appropriate primer pair was carried out 1 day after transfection. In these constructions, pCX/Ex/EIE/B was derived from genomic sequence of C57BL/6 mice, and pCX/Ex/EIE/M was from MRL/MpJ. A spliced band was detected in pCX/Ex/EIE/B, but was present little or very weakly in pCX/Ex/EIE/M. Next, the same spliced band was demonstrated in the pCX/Ex/EIE/M(T) plasmid, in which the branchpoint sequence (BPS) of pCX/Ex/EIE/M including the exon 9 was changed into that of pCX/Ex/EIE/B. The splicing did not occur in the dell1/B mutant, in which 1960 nucleotides of the intron 8 were deleted, whereas it was detected in the del2/B plasmid deleted 1036 nucleotides in its middle region. These results suggest that the nucleotide T to A mutation of the BPS in the intron 8 is at least a sufficient for generation of splice variants (tr-1 and tr-2 Exo1).     

Epizootiologic survey for Babesia microti among small wild mammals in northeastern Eurasia and a geographic diversity in the beta-tubulin gene sequences

We previously reported that small wild rodents in Japan harbor two types of novel Babesia microti-like parasites (designated as Hobetsu and Kobe types), but not the type commonly found in the northeastern United States (U.S. type) where human babesiosis is endemic. To determine whether these new types of parasites are distributed in places surrounding Japan, an epizootiologic survey was undertaken in three geographically distant areas in northeastern Eurasia; South Korea, Vladivostok in Russia, and Xinjiang in China. Blood samples were collected from a total of 387 animals comprising 24 species. DNAs extracted from the samples were tested by nested PCR targeting babesial nuclear small-subunit rRNA gene (rDNA), which revealed that small rodents harboring B. microti exist in all three survey areas. Sequence analysis showed that all PCR-positive samples had rDNA sequences virtually identical to that of U.S.-type B. microti. However, when beta-tubulin gene sequences were compared, evident geographic variations were seen. By use of primers specific for each of the beta-tubulin genes of Kobe-, Hobetsu-, and U.S.-type parasites, a type-specific PCR was developed. Parasite with Hobetsu- or Kobe-type sequence was not detected from any of the three survey areas. These findings suggest that U.S.-type B. microti is widely distributed among small wild mammals in temperate zones of not only North America, but also Eurasia, whereas that Hobetsu- and Kobe-type parasites may be uniquely distributed in Japan.     

Detection of Cryptosporidium muris type oocysts from beef cattle in a farm and from domestic and wild animals in and around the farm

Cryptosporidium muris type oocysts were detected from 21 of 516 beef cattle in a farm. Then we surveyed Cryptosporidium oocysts in 348 beef and dairy cattle, 500 pigs, 101 dogs, 38 wild animals and 11 zoo-kept animals in and around the farm. Oocysts were detected from only 2 of 25 Japanese field mice, Apodemus speciosus in the same farm. Gene analysis suggested that the oocysts were different from the C. muris type bovine isolate.