Synthesis and fungicidal activity against Pyricularia oryzae of 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone derivatives

A series of novel 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone (benzo[b]thiazin-4-one) derivatives was obtained by cyclisation via thiosemicarbazides which were prepared by reaction of hydrazines and the corresponding isothiocyanates. Their fungicidal activity was evaluated against the rice blast fungus Pyricularia oryzae. Of this series, 2,5,8-trimethyl-6-(1-propyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl) chromone, 6-(1-butyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone, 6-(1-hexyl-3-methyl-5-thioxo-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone and 6-(1-allyl-5-thioxo-3-trifluoromethyl-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone were highly active (pEC₅₀>6·0). Structure–activity relationship studies using the capacity factor k′ as a hydrophobicity index suggested that the log k′ optimum for 2,5,8-trimethyl-chromone and -1-thiochromone derivatives was around 1·0, equivalent to a log P_ow value of c. 4·4. © 1998 SCI     

Histological and Immunohistochemical Evaluation of Canine Ovary

In the present study, 15 canine ovaries without morphological lesions were examined histologically and immunohistochemically by using a large number of proteins including AE1/AE3, cytokeratin7 (CK7), CK13, CK20, vimentin, desmin, alpha smooth muscle actin (alphaSMA), calponin, S100, Neurofilaments, Inhibinalpha, placental alkaline phosphatase (PLAP) and neuron-specific enolase. Ovarian structures observed in this study included surface epithelium (SE), cortical tubules (CT), tunica albuginea (TA), stromal cells (SC), internal endocrine cells (IE), rete ovarii (RO) and fallopian tubes (FT). SE, CT, RO and FT were broadly immunoreactive for desmin. Besides AE1/AE3 and vimentin, desmin was also closely linked to these structures. Rete ovarii forming a reticular structure showed a positive reaction to S100. Surface epithelium was immunoreactive for PLAP at a significantly high level. In conclusion, these results indicate a specific segment of immunoreactivity as well as the broad range of immunoreactivity in canine ovary. The distinct patterns of immunoreactive for various kinds of proteins will play an important role in facilitating their identification and discrimination even in a normal canine ovary with a complex structure.     

Immunohistochemical detection of inhibin-alpha, -betaB, and -betaA chains and 3beta-hydroxysteroid dehydrogenase in canine testicular tumors and normal testes.

Immunohistochemical detection of inhibin-alpha, -betaA and -betaB chains and 3beta-hydroxysteroid dehydrogenase (HSD) was carried out on primary testicular tumors from 15 dogs and normal testes from three adult dogs. Histopathologically, the tumors were composed of three types: Leydig cell tumors in five dogs, Sertoli cell tumors in five dogs, and seminoma in five dogs. In normal testes, immunostaining against inhibin-alpha, -betaA, and -betaB chains and 3beta-HSD revealed positive reactivity in the cytoplasm of Leydig cells. In testicular tumors, immunoreactive cells against inhibin-alpha, -betaA, and -betaB chains and 3beta-HSD were localized in all Leydig cell tumors but not in any Sertoli cell tumors or seminomas. The results of radioimmunoassay for plasma inhibin in dogs with Leydig cell tumors showed higher concentrations than those in dogs with Sertoli cell tumors and seminomas and those in normal dogs. The concentration of inhibin in the plasma was markedly decreased by the surgical removal of the Leydig cell tumor in one dog. Our findings suggest that inhibin is synthesized by normal and neoplastic Leydig cells in the canine testis, and the secreted inhibin may be inhibin A and inhibin B.     

Geographical variation in age–height relationships for dominant trees in Japanese cedar (Cryptomeria japonica D. Don) forests in Japan

In this study, we analyzed Japanese National Forest Inventory data to investigate the geographical variation in the relationship between tree height and age for dominant trees, and the effects of climatic conditions on these relationships. Our analysis focused on Cryptomeria japonica forests in 13 regions of Japan. The age–height relationships were classified into two regional groups that were distinguished by their climatic conditions. Several categories of climatic variables (warmth, solar radiation, precipitation, and snow depth) were significantly correlated with the parameters of a model for the age–height relationships. Our results also suggest the existence of a latitudinal cline for the maximum tree height of C. japonica in Japan. In regions with cold temperatures, deep snow, low solar radiation, and low summer precipitation, C. japonica shows a late-maturity pattern for height increase, with slow initial growth and a large maximum size. In regions with the opposite climatic conditions, it shows an early-maturity pattern with fast initial growth and small maximum size.     

Heterochromatin integrity affects chromosome reorganization after centromere dysfunction

The centromere is essential for the inheritance of genetic information on eukaryotic chromosomes. Epigenetic regulation of centromere identity has been implicated in genome stability, karyotype evolution, and speciation. However, little is known regarding the manner in which centromere dysfunction affects the chromosomal architectures. Here we show that in the fission yeast Schizosaccharomyces pombe, the conditional deletion of the centromere produces survivors that carry either a neocentromere-acquired chromosome at the subtelomeric region or an acentric chromosome rescued by intertelomere fusion with either of the remaining chromosomes. The ratio of neocentromere formation to telomere fusion is considerably decreased by the inactivation of genes involved in RNA interference-dependent heterochromatin formation. By affecting the modes of chromosomal reorganization, the genomic distribution of heterochromatin may influence the fate of karyotype evolution.