Comparison of the characters of the plaque-purified viruses from foot-and-mouth disease virus O/JPN/2000

At least two biotypes were observed at the 2nd passage stage after the isolation of Foot-and-mouth disease Virus (FMDV) O/JPN/2000 strain. These 2 types of viruses differed from their plaque phenotypes and were distinguishable by using a monoclonal antibody (MAb) 64G8 that was made for the FMDV O/JPN/2000 strain. One of these 2 biotypes formed small plaque (SP) and with immuno staining showed a positive reaction to MAb 64G8, while the other formed clear large plaque (LP) and did not react with MAb 64G8. The amino acid sequences of the capsid coding region (VP1-VP4) of the SP virus (SPV) and the LP virus (LPV) revealed two substitutions on the 133rd amino acid in VP2, and the 56th amino acid in VP3. These amino acid changes of SPV and LPV are Asn to Asp, Arg to His, respectively. The Arg of the 56th amino acid in VP3 that have been known as critical position of cell culture adapted virus. Only LPV showed high pathogenicity in suckling mice, and its LD(50) was calculated to be about 10(2) TCID(50)/0.1 ml. These results showed that the SPV that existed at the 2nd passage stage from isolation was a low virulence virus, which may suggest why the pathogenicity of O/JPN/2000 did not show clear symptoms in infected cattle.     

Type VII and XVII Collagen mRNA Expressions in Regenerated Epidermal Laminae in Chronic Equine Laminitis

To confirm ability forming the basement membrane of the regenerated laminar epidermis (rLE) in chronic laminitis, expression of type VII and type XVII collagen mRNAs in the rLE was studied applying sequences of two type of murine collagens. On northern blot analysis, complement DNA (cDNA) probes adjusted from the murine type VII and type XVII collagen could hybridize with the equine mRNAs, and each signal was detected as single-bands at approximately 9.5 kb and 5.6 kb, respectively. Contrasting with the expression level of equine glyceraldehyde-3-phosphate dehydrogenease mRNA, the band of type VII collagen mRNA in laminitis was stronger than normal, but the type XVII collagen mRNA in laminitis was less than normal. By in situ hybridization, positive signals in response to the murine type VII and type XVII collagen mRNA probes could be detected in the equine laminitic rLE region. From these results, it is concluded that the keratinocytes constructing the rLE in chronic stage of laminitis can express type VII and type XVII collagen mRNAs and these expression patterns were different from the normal.     

A survey of antimicrobial resistance in Escherichia coli isolated from wild sika deer (Cervus nippon) in Japan

We examined the antimicrobial susceptibility of 848 Escherichia coli isolates from 237 feces samples of wild sika deer (Cervus nippon) captured between 2016 and 2019 in 39 of the 47 prefectures of Japan. Five of the 237 wild sika deer (2.1%) carried E. coli with resistance to at least one antimicrobial, and all the resistant isolates showed resistance to tetracycline. The resistant isolates contained antimicrobial resistance genes that were similar to those in E. coli derived from humans and farm animals. Although wild sika deer are not currently likely to be a source for the transmission of antimicrobial resistance in Japan, they can potentially mediate antimicrobial resistance spread by coming into contact with humans, animals, and their surroundings.     

Immunohistochemical study on the delayed progression of epithelial apoptosis in follicle-associated epithelium of rat Peyer's patch

It is well known that some caspases in apoptosis is involved in determinant of terminal differentiation and maturation of various cells. Our previous study ultrastructurally clarified the differentiation into M cells from immature microvillous epithelial cells and the redifferentiation from M cells to microvillous epithelial cells in the follicle-associated epithelium (FAE) of rat Peyer's patch. In this study, the difference of epithelial apoptosis between the FAE of Peyer's patch and intestinal villi was immunohistochemically investigated in rat jejunoileum. As a result, cleaved caspase-3 was limited to several epithelial cells at the tip of FAE, whereas almost all of the epithelial cells were cleaved caspase-3 positive in intestinal villi. Cleaved caspase-9 was detected only in a few exfoliating or exfoliated epithelial cells of both FAE and intestinal villi. Nuclear DNA-fragmentation was detected only in several epithelial cells of the tip of FAE, while it was expressed from the middle regions in the intestinal villi. The DNase I expression of the epithelial cytoplasm was much weaker in FAE than in intestinal villi. Bcl-x expression was restricted in the apical cytoplasms of epithelial cells in the FAE, whereas it was restricted in whole cytoplasms in villous epithelial cells. These findings suggest that the progression of the apoptotic process in the epithelial cells of FAE is later than in the intestinal villi, so that the possibility of epithelial differentiation might be remained in the FAE, unlike in the intestinal villi.     

Quantitative structure-activity studies of benzoylphenylurea larvicides: I. Effect of substituents at aniline moiety against Chilo suppressalis walker

The larvicidal activity of a series of N-2,6-difluoro- and N-2,6-dichlorobenzoyl-N′-(4-substituted phenyl)ureas against nondiapause larvae of the rice stem borer, Chilo suppressalis Walker, was measured by topical application and oral administration methods under conditions with and without piperonyl butoxide as an inhibitor of oxidative metabolism. The effects of substituents at the anilide moiety on the larvicidal activity were analyzed quantitatively using physicochemical substituent parameters and regression analysis. The results indicate that the oxidative metabolism in the larval body which is favored by electron-donating substituents is significant in determining the activity. The activity, when the metabolic factor is eliminated, is enhanced by electron-with-drawing and hydrophobic substituents and lowered by bulky groups. The inhibitory activity against new cuticle formation of the same series of compounds was also measured using cultured integument of the rice stem borer diapause larva. The comparison of the quantitative analyses between larvicidal and integument-level activities shows that inhibition of cuticular development is the most important factor governing larvicidal activity.     

A spontaneously occurring malignant ovarian Sertoli cell tumor in a young Sprague Dawley rat

Primary ovarian tumors are generally uncommon in rats used in toxicologic studies. A malignant Sertoli cell tumor was present in the ovary of a 19-week-old female Sprague Dawley rat. Macroscopically, the mass was white and firm, 10 × 13 × 17 mm in size, and located in the right ovary. Histopathologically, the mass was composed of nests of pleomorphic cells, which formed seminiferous-like tubules separated by a thin fibrovascular stroma. The tubules were lined by tumor cells, which had basally located nuclei and abundant eosinophilic and vacuolated cytoplasm. In some areas, the tumor cells were arranged in a retiform growth pattern, mimicking a rete testis/ovarii. Disseminated metastases to the surfaces of the mesentery, spleen and liver were also present. Immunohistochemically, many tumor cells were strongly positive for vimentin, estrogen receptor α and Ki 67. Some tumor cells were positive for pancytokeratin and inhibin α. These findings closely resemble those of an ovarian-derived human malignant Sertoli cell tumor. From our review of the literature, we believe this is the first report of a spontaneous malignant Sertoli cell tumor in the ovary of a young laboratory rat. This case might provide useful historical control information for rat toxicity studies.     

Genotypic effects on the variation of wood quality and growth traits in plantation forest made by cutting cultivars of Japanese cedar

We studied the effect of genotypes of planting stocks regarding the variation of the modulus of elasticity of tree trunks on standing trees (trunk-MOE), tree height (TH), and diameter at breast height (DBH) in a 19-year-old Japanese cedar plantation made with root cuttings. Trunk-MOE was assessed nondestructively using a tree-bending method. Genotypes of individual trees were detected using the random amplified polymorphic DNA (RAPD) technique. RAPD analysis revealed that the sampled plantation consisted of 14 genotypes. Genotypic effects on DBH and TH were unclear, and there was no significant difference among genotypes. This result indicated that an acquired variation should have more influence than an inherited variation on DBH and TH. For trunk-MOE, there were significant differences among the four largest genotypes at the 5% level. However the coefficient of variation in trunk-MOE of each genotype ranged from 7.5% to 26.8%. It seems reasonable to assume that the wide variation in trunk-MOE in a sampled plantation may depend on the environmental effect within a clone as well as on the genetic origin of clones. We therefore conclude that the use of multiple planting stocks from different cuttings for which the wood quality is unknown contributed strongly to the wide variation in trunk-MOE in the plantation of Japanese cedar.     

A Computer Program for Automatic Watering Based on Potential Evapotranspiration by Penman Method and Predicted Leaf Area in Miniature Pot Rose Production

In this study, we developed a computer program for automatic prediction of watering time point by considering the environmental factors such as solar radiation, air temperature and relative humidity based on the multiple linear regression equation of leaf area and Penman Method. The experiments were carried out for a year in two watering experimental plots, one of which was controlled by pF value, and the other by the computer program. After comparing the results of the two plots, the following findings were obtained. In the computer program plot, the observed and predicted values of both leaf area and evapotranspiration indicated significant correlation at the 1% level, which suggested that the computer program had high prediction accuracy. In addition, no significant difference was observed between the two experimental plots with respects to the plant height, plant diameter, leaf area, leaf number, fresh weight, and dry weight, which demonstrated that the plants in the computer program plot had normal growth. On the other hand, although the number of flower buds and flowering shoots showed higher values at the end of certain cultivations in the computer program plot than those in pF value plot, we proposed that it was due to the effect of cumulative daily solar radiation in the greenhouse, rather than the watering. Thus, we have reached the conclusion that the computer program for automatic prediction of watering time point developed by this study has high applicability in miniature pot rose production.     

Evaluation of relationship between dispersibility of soils and charge characteristics using a modified ion adsorption method; An example of soils from Wakayama Prefecture,Japan

The relationship between the charge characteristics and the dispersibility of soils from reclaimed land (highly dispersive) and adjacent forest area (physically stable) was investigated.

To evaluate the amount of soil charges quantitatively, the measurement based on cation and anion adsorption (ion adsorption method) was attempted in two ways, where special attention was paid to the solution concentration. In the conventional ion adsorption method, the treatments with concentrated solutions (1 mol L^-1) were included in the process. In the modified method, soils were treated with dilute solutions (5 mmol L^-1), in taking account of the soil solution concentration in humid temperate regions. The amount of charges derived from the modified method was smaller than that from the conventional one, especially in the high pH zone. In a preliminary experiment, the extraction of polyvalent cations from soils was found to be significantly affected by the salt concentration. Thus, the use of solutions with an excessively high concentration was considered to result in an error in the estimation of the active charges in soils which would contribute to the dispersion behavior in the field.

The applicability of the modified method for analyzing the dispersion behavior of soils was evaluated by relating the dispersibility of silts and clays at different pHs with the charge characteristics determined under the same ionic strength. The dispersion ratio of silts of the reclaimed land reached maximum values at pH 5.5, above which the ratio decreased, whereas the ratio of clays began to increase in the pH range above 6. The dispersion ratio of silts of the forest area increased in the pH range above 6, whereas that of clays remained constant at a low level in all the pH ranges below 7. The changes in the dispersibility of silt plus clay fractions corresponded to total charge characteristics determined by the modified method. Thus, the evaluation of soil charges by the modified ion adsorption method was considered to be effective to predict soil dispersibility under field conditions, indicating that it could replace electrokinetic analyses such as electrophoresis in studies on the dispersion/flocculation behavior of soils.     

Ontogeny of testicular inhibin and activin in ducks: An immunocytochemical analysis

The ontogeny of testicular inhibin/activin in ducks was investigated. Testicular localization of three inhibin/activin subunits (α, β_A and β_B) was determined in embryonic and newly hatched ducks from 12 days of incubation to 1 day of age, in immature ducks and in adult ducks. In the duck embryonic testis, positive α‐subunit immunostaining was first detected in the Leydig cells and Sertoli cells on day 15 of incubation, whereas β_A‐subunit and β_B‐subunit immunostaining were found in Sertoli cells and primary germ cells on day 18 of incubation. In 1 month old ducks, intense staining of α‐subunit was present in the seminiferous epithelium consistent with localization in Sertoli cells and primary germ cells, and the immunostaining of the β_A‐ and β_B‐subunit was also present in Sertoli cells and primary germ cells. Specific immunostaining with inhibin/activin α‐, β_A‐ and β_B‐subunits antisera occurred in Sertoli cells in the adult duck testes. In conclusion, it was shown that, in the duck testis, the majority of α‐, β_A‐ and β_B‐subunits are colocalized in Sertoli cells with a certain degree of staining in germ cells and the α‐subunit is present in Leydig cells of embryonic testes before day 18 of incubation. These results indicate that Sertoli cells and possibly germ cells in the embryonic testes of late stage of incubation and newly hatched ducks, immature ducks and mature ducks may produce bioactive inhibin dimers, inhibin A and inhibin B, as a possible regulator of follicle‐stimulating hormone secretion. Free inhibin/activin subunits and their dimers may also play an autocrine/paracrine role in the development of the testis and spermatogenesis. Furthermore, early onset of the α‐subunit in duck testes indicates that it may have an autocrine/paracrine effect on steroid hormones, which is important for sex differentiation.