Plectosphaerella rot of lettuce, coriander, and chervil caused by Plectosphaerella pauciseptata

Rot diseases of hydroponically cultured leaf lettuce, coriander, and chervil were found in Chiba Prefecture, Japan. Stems and petioles of the three diseased plants became brown or black with a soft rot, and vascular parts of the stems became discolored. Seemingly similar fungi were isolated from the diseased plants. Pathogenicity of these fungal isolates to each plant was demonstrated by inoculation tests. The fungi were identified as Plectosphaerella pauciseptata based on morphological and cultural characters. This identification was supported by phylogenetic analysis with rDNA ITS1-5.8S-ITS2 regions. The diseases were named Plectosphaerella rot (Plectosphaerella huhai-byo in Japanese) of lettuce, coriander, and chervil.     

White root rot disease of the lacquer tree <Emphasis Type="Italic">Toxicodendron vernicifluum</Emphasis> caused by <Emphasis Type="Italic">Rosellinia necatrix</Emphasis>

In early August 2010, lacquer trees (Toxicodendron vernicifluum) severely damaged by a root rot disease were found on plantations in Iwate, Japan. The causal agent was a fungus identified as Rosellinia necatrix, based on morphology and the sequence of the ribosomal DNA internal transcribed spacer region. The fungus was clearly pathogenic on T. vernicifluum root plantings. This report is the first of white root rot on T. vernicifluum.     

Egg collection from hatchery-reared broodstock of spotted halibut Verasper variegatus treated with LHRH analog

The objective of this study is to establish a method for acquiring large quantities of high-quality eggs for artificial fertilization from hatchery-reared broodstock of spotted halibut Verasper variegatus. We estimated the optimum conditions for implantation of luteinizing hormone-releasing hormone analog (LHRHa) cholesterol pellet (LHRHa-CP) to induce ovulation from two experiments which focused on the dose and the timing combined with monitoring of oocyte development by ovarian cannulation. From the results of cannulation, vitellogenesis of hatchery-reared broodstock was suggested to occur normally, although final oocyte maturation was not initiated in the first clutch of oocytes. In late December, oocytes in the most advanced clutch still underwent vitellogenesis, having diameter of about 0.82?mm. LHRHa-CP implantation during this period had no remarkable effects, except for administration at high dose (100???g/kg). In contrast, in mid January, when oocyte diameter reached about 0.95?mm, ovulation occurred in most individuals, even at low dose (20???g/kg). In mid February atretic oocytes became remarkable and LHRHa-CP implantation showed much lower performance in terms of egg quality. The diameter of growing oocytes converged to about 0.95?mm, which was that of fully grown postvitellogenic oocytes. Thus, oocyte diameter is suggested to be an effective indicator to estimate the timing of LHRHa-CP implantation.     

Age,growth and age at sexual maturity of fan ray <Emphasis Type="Italic">Platyrhina sinensis</Emphasis> (Batoidea: Platyrhinidae) in Ariake Bay,Japan

Abstract:   Age, growth and sexual maturity of the fan ray Platyrhina sinensis in Ariake Bay, Japan were determined from specimens collected from May 2002 to September 2006. Age determination was conducted by vertebral centrum analysis using soft X-radiography. Annual band pair deposition was determined by marginal increment and edge analyses. The von Bertalanffy growth model best described the overall pattern of growth for both males and females (males L _∝  = 455.2, k  = 0.56, t ₀ = −1.09; females L _∝  = 555.8, k  = 0.28, t ₀ = −1.77; L _∝ is the theoretical asymptotic total length in mm, k is the growth rate coefficient and t ₀ is the theoretical time at zero length). Parameter estimates suggest that females attain a larger asymptotic total length and grow more slowly than males. The observed maximum ages were 5 years for males and 12 years for females. Age at 50% sexual maturity was 2.1 years for males and 2.9 years for females. The results indicate that this species is relatively fast-growing, short-lived and early maturing compared with many batoid species.     

Changes in serum vitellogenin levels and immunohistochemical localization of vitellogenin in hepatic cells during ovarian development in the Japanese eel

ABSTRACT: The present study was designed to quantify changes in serum vitellogenin (VTG) levels and to localize VTG in hepatic cells immunohistochemically during artificial maturation of the Japanese eel Anguilla japonica . Hormone treatment resulted in a gradual rise in serum VTG levels, in which the highest values were attained at the migratory nucleus stage. Hepatocytes responded to hormone treatment by increased immunoreactivity; both staining area and intensity were enhanced with ongoing gonadal development. Moreover, cytoplasmic vacuoles increased in number during artificial maturation, occupying large areas inside hepatocytes. The unusual appearance of hepatocytes may reflect the effect of artificial maturation.     

Advanced backcross QTL analysis reveals complicated genetic control of rice grain shape in a japonica × indica cross

Grain shape is an important trait for improving rice yield. A number of quantitative trait loci (QTLs) for this trait have been identified by using primary F₂ mapping populations and recombinant inbred lines, in which QTLs with a small effect are harder to detect than they would be in advanced generations. In this study, we developed two advanced mapping populations (chromosome segment substitution lines [CSSLs] and BC₄F₂ lines consisting of more than 2000 individuals) in the genetic backgrounds of two improved cultivars: a japonica cultivar (Koshihikari) with short, round grains, and an indica cultivar (IR64) with long, slender grains. We compared the ability of these materials to reveal QTLs for grain shape with that of an F₂ population. Only 8 QTLs for grain length or grain width were detected in the F₂ population, versus 47 in the CSSL population and 65 in the BC₄F₂ population. These results strongly suggest that advanced mapping populations can reveal QTLs for agronomic traits under complicated genetic control, and that DNA markers linked with the QTLs are useful for choosing superior allelic combinations to enhance grain shape in the Koshihikari and IR64 genetic backgrounds.     

Mycoplasma ovis detected in free-living Japanese serows, Capricornis crispus

Nineteen blood samples collected from free-ranging wild Japanese serows, Capricornis crispus, between 2006 and 2008 in Iwate prefecture were examined for the hemoplasma infection by real-time PCR targeting the 16S rRNA gene. Five (26.3%) out of the 19 samples were positive in real-time PCR with an average melting temperature at 85.18 °C. The positive samples in the real-time PCR were reconfirmed by conventional PCR, and one of them was successful for direct DNA sequencing. The nucleotide sequence of the 16S rRNA gene of the representative stain was identical to that of Mycoplasma ovis. This was the first demonstration of hemotropic mycoplasma infections among the free-living Japanese serows in Japan.     

Food variations and ontogenetic dietary shift of the starspotted-dogfish Mustelus manazo at five locations in Japan and Taiwan

SUMMARY: Stomach contents were examined from 936 individuals of Mustelus manazo , collected by trawl at five locations: Aomori, Tokyo Bay, Maizuru and Shimonoseki in Japan, and one location off Taiwan. The vacuity index was relatively low (0–6.1%). Based on three indices ( %W , %F , RI ), the major dietary component was crustaceans at all locations. The most important prey category was crabs in Aomori, Shimonosei and Taiwan, mantis shrimps in Tokyo Bay, and shrimps in Maizuru. Fishes were a minor food category for M. manazo in most locations, except in Maizuru where fishes were second in importance in the diet. Dietary overlap revealed a medium degree of overlap between Tokyo Bay and Aomori, and between Tokyo Bay and Shimonoseki. The other locations showed a high degree of overlap with each other. Significant ontogenetic dietary shifts were found in Tokyo Bay, Maizuru and Taiwan, and prey diversity showed a trend being relatively low in larger size classes. The feeding habit of M. manazo was unique in Tokyo Bay, where crustaceans in the muddy substrata were taken in preference to the most abundant benthic prey item available, such as a southern rough shrimp, Trachypenaeus curvirostris . Mustelus manazo appears to use two feeding strategies based upon stomach contents. One, in Tokyo Bay, involved the digging up or removing of burrowing invertebrates from muddy substrata without crushing them. The other, at the other four locations, involved the crushing of prey on the substrata surface.     

Intraocular peripheral nerve sheath tumor in a dog

A tumor within the right globe in a 9-year-old Shetland sheepdog was examined pathologically. The tumor was composed of spindle or oval cells arranged in interwoven bundles with intervening collagenous or mucinous matrices. Immunohistochemically, the tumor bound antibody directed to S-100 protein and vimentin, but not to desmin, actin smooth muscle, or neurofilament. Electron microscopy revealed that the tumor cells had poorly developed cytoplasmic processes, desmosomes between closely contiguous cells, and a discontinuous basement membrane-like material. Based on these findings, the tumor was diagnosed as a peripheral nerve sheath tumor (PNST) histologically. To the authors' knowledge, this is the first reported case of intraocular PNST in dogs.     

Mutation of the GABA receptor associated with fipronil resistance in the whitebacked planthopper, Sogatella furcifera

We found the A2′N mutation (index number for M2 membrane spanning region) in the GABA receptor subunit of fipronil-resistant Sogatella furcifera, by analyzing DNA sequences amplified from fipronil-resistant and -susceptible S. furcifera. In order to confirm the role of A2′N mutation in the fipronil resistance, we expressed the wild-type and A2′N mutant Drosophila GABA receptors in Drosophila Mel-2 cells stably. Amino acid sequences of three membrane spanning regions (M1-M3), which are important for binding of fipronil, are conserved between Drosophila and S. furcifera. So the results of A2′N mutant Drosophila GABA receptor suggest the role of A2′N mutation in fipronil-resistant S. furcifera. The membrane potential assay showed that the A2′N mutant Drosophila GABA receptor was not inhibited by fipronil at all, while the IC₅₀ value of fipronil for wild-type Drosophila GABA receptor was 172 nM. These results suggest that A2′N mutation confers the resistance of fipronil in S. furcifera.