Assessing sexual maturity of feminized Japanese eel Anguilla japonica by measuring eye size

For efficient production of Japanese eel Anguilla japonica eggs, knowledge of the status of the sexual maturity of potential broodstock females is important because this status directly influences the time required to produce mature eggs by successive hormone doses. Here we apply an eye index (relative eye size) to evaluate the gonadal status of feminized A. japonica, which were induced by administration of estradiol-17β. Examination of gonad somatic and eye indexes of 267 feminized eels, cultivated for 12–56 months, revealed a significant correlation between these two indexes. Artificial maturation of 35 feminized eels showed that the number of hormone injections administered before ovulation was significantly lower as the eye index score increased, indicating availability of this noninvasive method of predicting sexual maturity of feminized eel. There was no correlation between eye index and fertilization rate, hatching rate, or larval survival rate, suggesting that sexual maturity before hormonal treatment does not affect egg quality.     

Severe nonpurulent encephalitis with mortality and feather lesions in call ducks (Anas platyrhyncha var. domestica) inoculated intravenously with H5N1 highly pathogenic avian influenza virus

One-day-old, 2-wk-old, and 4-wk-old call ducks (Anas platyrhyncha var. domestica) inoculated intravenously with the H5N1 highly pathogenic avian influenza virus A/chicken/Yamaguchi/7/2004 isolate (Ck/Yama/7/04) were examined clinically, pathologically, and virologically. Clinically, the birds exhibited mild-to-severe neurologic signs and corneal opacity. All birds in the 1-day-old group and one bird in the 4-wk-old group died within 4 days after the virus inoculation. Histologic changes were characterized by severe nonpurulent encephalitis and necrotic lesions of feather epithelium on day 3 postinoculation (PI) or later. Focal necrosis of myocardial cells, pancreatic acinar cells, skeletal myocytes, and corneal epithelial cells was observed. Viral antigens were detected in association with necrotic changes. Viruses were isolated from all examined organs including the skin with many feathers. Serum antibody against the virus was detected in all surviving birds on day 10 PI by hemagglutination-inhibition tests. These results suggest that Ck/Yama/7/04 has a pathogenicity that causes neurologic sign, nonpurulent encephalitis with mortality, and feather lesions for call ducks. Feather lesions with viral antigens and the virus isolation from the skin suggest that Ck/Yama/ 7/04 has a predilection for feathers in call ducks.     

Nematicidal activity of essential oils and their components against the root-knot nematode

ABSTRACT Nematicidal activity of essential oils extracted from 27 spices and aromatic plants were evaluated in vitro and in pot experiments. Twelve of the twenty-seven essential oils immobilized more than 80% of juveniles of the root-knot nematode Meloidogyne javanica at a concentration of 1,000 mul/liter. At this concentration, most of these oils also inhibited nematode hatching. Essential oils of Carum carvi, Foeniculum vulgare, Mentha rotundifolia, and Mentha spicata showed the highest nematicidal activity among the in vitro tested oils. These oils and those from Origanum vulgare, O. syriacum, and Coridothymus capitatus mixed in sandy soil at concentrations of 100 and 200 mg/kg reduced the root galling of cucumber seedlings in pot experiments. The main components of these essential oils were tested for their nematicidal activity. Carvacrol, t-anethole, thymol, and (+)-carvone immobilized the juveniles and inhibited hatching at >125 mul/liter in vitro. Most of these components mixed in sandy soil at concentrations of 75 and 150 mg/kg reduced root galling of cucumber seedlings. In 3-liter pot experiments, nematicidal activity of the essential oils and their components was confirmed at 200 and 150 mg/kg, respectively. The results suggest that the essential oils and their main components may serve as nematicides.     

Down regulation of a novel protein,PSP, in rat hepatoma cdRLh 84-beared tumor

Perchloric acid-soluble protein (PSP) is a members of a new hypothetical family (YER057c/YJGF family) of small proteins with presently unknown function. The high degree of evolutionary conservation of these proteins reflect an involvement in basic cellular regulation. The expression of PSP was examined in rat hepatoma cell dRLh 84-beared rats. The tumor weight increased to 4.24 g at 3 weeks after the transplantation of hepatoma cells and hepatoma which has less differentiated characteristics were observed in rat liver. The expression of PSP in rat hepatoma was down regulated as compared with intact tissue. Thus the expression of PSP seems to be associated with the differentiation process in these transformed cells. On the other hand, some positive cells against the PSP-antibody were observed in the central region of tumor tissue by immunohistochemistry. These cells were shown to be the lymphocytes and the macrophages. The involvement of PSP to cellular growth and differentiation is discussed.     

Detoxification of α-tomatine by tomato pathogens Alternaria alternata tomato pathotype and Corynespora cassiicola and its role in infection

In tomato plants, α-tomatine, a steroidal glycoalkaloid saponin, inhibits fungal growth. Tomato pathogens that produce host-specific toxins, Alternaria alternata tomato pathotype causing Alternaria stem canker and Corynespora cassiicola causing Corynespora target spot, were investigated for sensitivity to α-tomatine. Although spore germination of A. alternata pathogenic and nonpathogenic to tomato and of C. cassiicola pathogenic to tomato was not affected by 0.1 mM α-tomatine, spore germination of C. cassiicola nonpathogenic to tomato was significantly inhibited. This result showed that A. alternata, regardless of its pathogenicity, and only the C. cassiicola pathogenic to tomato are resistant to α-tomatine. Germinating spores of A. alternata and C. cassiicola resistant to α-tomatine detoxified α-tomatine by degrading it to a less polar product. After inoculation of tomato leaves, spores of A. alternata and C. cassiicola nonpathogenic to tomato germinated and formed appressoria, but did not form infection hyphae in host tissues. When a host-specific toxin (CCT-toxin) produced by C. cassiicola pathogenic to tomato was added to nonpathogenic spores, colonization within leaves was observed in A. alternata, but not in C. cassiicola. On the other hand, when spores of C. cassiicola nonpathogenic to tomato were suspended in spore germination fluid of nonpathogenic A. alternata with α-tomatine detoxification activity, the fungus could be induced to colonize leaves in the presence of CCT-toxin. These results indicate that A. alternata tomato pathotype and C. cassiicola pathogenic to tomato detoxify α-tomatine during infection and that this detoxification is essential for host colonization by pathogens that produce host-specific toxins.     

Lignan production inDaphne odora cell cultures

Lignan production in callus and cell suspension cultures ofDaphne odora is reported for the first time. The cell suspension culture produced pinoresinol, lariciresinol, secoisolariciresinol, matairesinol, and wikstromol. The production of matairesinol in the cell suspension culture was much higher than that inDaphne odora stem tissues.Part of this report was presented at the 51th annual meeting of the Japan Wood Research Society, Tokyo, April 2001     

New lignan, isoactifolin, fromChamaecyparis obtusa cv. Breviramea

A new lignan isoactifolin was isolated from young shoots (with leaves) ofChamaecyparis obtusa cv. Breviramea. The structure of the compound was determined based on spectroscopic evidence.Parts of this report were presented at the 44th lignin symposium, Gifu, October 1999