Identification of Trichoderma SKT-1, a biological control agent against seedborne pathogens of rice

Trichoderma SKT-1 was previously reported as a powerful biological control agent against seedborne pathogens of rice, but the taxonomic disposition of the fungal isolate was not clear. Trichoderma SKT-1 produced irregular pyramidal warts on conidia and had an optimum growth temperature of 30°C. Morphological characteristics and colony growth were identical to those of known species of Trichoderma, including the newly recognized species T. asperellum. The 5.8S rDNA with the internal transcribed spacer (ITS) region (ca. 514 bp) of the fungus was compared with those of known species to determine the phylogenetic placement of the fungus. The length and sequence of the regions from Trichoderma SKT-1 were completely identical to those of an isolate of T. asperellum NRRL 5242 (AJ230669). On the basis of these results, we concluded that Trichoderma SKT-1 was T. asperellum.     

Regulation of gonadotropin subunit genes expression by 11-ketotestosterone during early spermatogenesis in male red seabream, Pagrus major

To examine the roles of gonadal steroids in the regulation of expression of gonadotropin subunit genes, male red seabream were gonadectomized and a sub-group was treated with 11-ketotestosterone (11-KT). Castration of males during the early stage of spermatogenesis elicited a significant increase in FSHβ mRNA levels, which was prevented by 11-KT replacement. By contrast, LHβ mRNA levels were not changed by castration or 11-KT replacement. In addition, administration of 11-KT to sham-operated males suppressed the steady-state FSHβ and LHβ mRNA levels. These results indicate that 11-KT may function as a negative feedback regulator of FSHβ gene expression, and may act through the testis to down-regulate LHβ mRNA levels in male red seabream during this period.     

‘Niigata S3’ is a new strawberry cultivar suitable for forcing culture under low temperature and insolation conditions

‘Niigata S3’ is a new strawberry (Fragaria × ananassa Duch.) cultivar that is early flowering and possesses high soluble solid content and good coloration. It was selected from a cross between Kei812 (seed parent) and ‘Asuka-Ruby’ (pollen parent). The first harvest date of ‘Niigata S3’ was December 27, 34 days earlier than ‘Echigohime’ and 9 days earlier than ‘Asuka-Ruby’ (means of 2007 and 2008). The marketable yield of ‘Niigata S3’ was 85% of ‘Echigohime’, 107% of ‘Asuka-Ruby’, while the early yield was 145% of ‘Echigohime’, 85% of ‘Asuka-Ruby’ (based on 2007 and 2008 means). The shape of the fruit is long conical, and its skin color medium-red. The fruit skin hardness of ‘Niigata S3’ was 31.5 g/mm², which was harder than ‘Echigohime’, and its average soluble solid content was 11.4%, which was higher than the values for ‘Echigohime’ and ‘Asuka-Ruby’ (2008). Furthermore, ‘Niigata S3’ did not bear apical overripe fruit. This new cultivar is adaptable to the climatic conditions of Niigata, as well as other regions that experience low winter temperatures and insolation.     

Quantitative and qualitative changes of organic matter in an Ando soil induced by mineral fertilizer and cattle manure applications for 20 years

The effects of continuous application of cattle manure on the quantity and quality of soil organic matter (OM) were investigated in an Ando soil (Melanudand). Surface soil samples were periodically taken from NPK and NPK+ manure (80, 160, and 320 Mg ha^-1 y^-1) plots over a period of 20 y. Particulate (>53 µm) and mineral-associated <53 µm) OM fractions were separated from the soil samples by sieving after:mechanical dispersion. For the NPK treatment, both the organic C and total N concentrations of the whole soil continued to decrease, the reduction reaching about 10% after 20 y. Manure application at the rate of 80 Mg ha^-1 y^-1 did not lead to an increase in the amounts of organic C and total N in the whole soil. In contrast, both the organic C and total N concentrations increased by the application of 160 and 320 Mg ha^-1 y^-1 manure. Manure application at the rate of 320 Mg ha^-1 y^-1 increased the organic C concentration by 30% and total N concentration by 48% after 20 y. The decrease in the organic C and total N concentrations in soil with NPK fertilization was attributed to a decrease in the amount of mineralassociated OM. Manure application increased significantly the amount of particulate OM, while it did not affect the amount of mineral-associated OM. It also resulted in a decrease in the C/N ratio of soil OM, especially of the particulate OM. The analysis of humic acids showed that manure application induced a decrease in the degree of humification and an accumulation of high molecular weight components. The quantitative'and qualitative changes of OM in the Ando soil upon manure application were mainly due to the accumulation of manure-derived particulate OM.     

Physiological roles of FSH and LH in red seabream, Pagrus major

The duality of gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), has been confirmed in most teleost species, but very little is known about their biological functions. To elucidate the physiological roles of FSH and LH in fish reproduction, the expression profiles of GTH subunit genes during gonadal development were analyzed in both male and female red seabream. Furthermore, in vitro studies were carried out to examine the effects of GTHs on steroid hormone production and cytochrome P450 aromatase (P450arom) expression in red seabream gonads. In both sexes, LHβ mRNA was maintained at high levels from the early gametogenesis until spawning season, and declined with gonadal regression. Interestingly, FSHβ mRNA levels in males increased in parallel with testicular development, whereas those in female were remained low throughout oocyte development. From in vitro studies using purified red seabream FSH and LH, both GTHs had a similar potency in stimulating 11-ketotestosterone production by testicular slices, while the biological activity of FSH was much lower than that of LH in stimulating production of estradiol-17β by vitellogenic follicles. Moreover, expression of P450arom mRNA was induced by LH, but not FSH, in ovarian follicles in vitro. FSH was also ineffective in inducing maturational competence and final oocyte maturation. These results suggest that, unlike salmonids, FSH may play an important role during gametogenesis in male, but not female, red seabream, whereas LH may be involved in regulation of both early and late gametogenesis in both sexes.     

Effects of 11-ketotestosterone and gonadotropin-releasing hormone on follicle-stimulating hormone and luteinizing hormone gene expression in castrated and sham-operated male red seabream <Emphasis Type="Italic">Pagrus major</Emphasis>

ABSTRACT:   In order to clarify the roles of androgen and gonadotropin-releasing hormone (GnRH) on gonadotropin (GTH; luteinizing hormone [LH] and follicle stimulating hormone [FSH]) synthesis, effects of castration and implantation of GnRH analog (GnRHa) or 11-ketotestosterone (11-KT) on expression of GTH subunit, α-glycoprotein subunit (αGSU), FSHβ, and LHβ genes, during the early spermatogenic stage in male red seabream Pagrus major were examined. Male red seabream underwent castration or sham-operation and were subsequently implanted with cholesterol pellets containing GnRHa, silicone capsules filled with 11-KT, or blank capsules (control). FSHβ mRNA levels increased due to castration, and it was reversed by treatment with 11-KT. 11-ketotestosterone treatment also decreased FSHβ mRNA levels in sham-operated fish. These results suggest that 11-KT acts on the pituitary to suppress FSH synthesis in male red seabream. On the other hand, neither castration nor replacement of 11-KT in castrated fish had effects on LHβ mRNA levels, whereas 11-KT treatment had slightly but significantly decreased LHβ mRNA in sham-operated fish. αGSU mRNA levels were not changed by castration or 11-KT treatment in both sham-operated and castrated fish. Meanwhile, treatment with GnRHa significantly decreased FSHβ mRNA levels in sham-operated fish, but not in castrated fish. This suggests that GnRHa may down-regulate expression of FSHβ mRNA through the production of 11-KT in testis. LHβ and αGSU mRNA levels in sham-operated fish, but not in castrated fish, were significantly elevated by treatment with GnRHa.     

Pharmacological effects of Ganoderma lucidum collected from ume (Japanese apricot) trees

We performed functional evaluation of the fruiting bodies of Ganoderma lucidum growing on ume trees (Japanese apricot, Prunus mume), and determined the suitability of pruned ume branches as a basic component of culture medium for this mushroom. We observed that all tested functional activities of the fruiting bodies of G. lucidum collected from ume trees were higher than those collected from other broadleaf trees or cultured artificially; the functional tests were angiotensin I-converting enzyme inhibitory activity, a platelet aggregation inhibition test, and an interleukin-8 (IL-8) gene expression inhibition test. When extracts from fruiting bodies of G. lucidum were orally administered to spontaneous hypertensive rats, hypotensive effects were found. Freeze drying was the most suitable procedure for preservation of the extracts, and the activities of 30% ethanol extracts and 30% methanol extracts were higher than those of hot-water extracts. The highest functional activities for extracts from G. lucidum mycelia cultured on sawdust media were for sawdusts based on ume wood. Part of this study was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006     

Mechanism of resistance to carpropamid in Magnaporthe grisea

The inhibitory activity of carpropamid on scytalone dehydratase (SDH) extracted from a carpropamid-resistant strain of Magnaporthe grisea (Hebert) Barr was dramatically reduced in comparison with that on SDH extracted from the sensitive strain. A single-point mutation (G to A) located at the upstream region (233 bp downstream from the ATG codon) resulting in a one-amino-acid substitution (valine [GTG] 75 to methionine [ATG]: V75M) was found in the resistant strain. To examine whether the V75M mutation is the primary reason for decreasing the sensitivity of SDH to carpropamid, the SDH cDNAs of both the sensitive and the resistant strain were cloned into a GST-fused protein expression vector-system. The recombinant SDHs of both strains exhibited the same sensitivities to carpropamid as those extracted from the mycelia of the respective strains. These data clearly revealed that the V75M mutation causes the low sensitivities of the SDHs of the carpropamid-resistant strains, and strongly suggests that the V75M mutation confers resistance of these strains to carpropamid.