Immunohistochemical observations of vitellin synthesis and accumulation processes in ovary of Ezo abalone <Emphasis Type="Italic">Haliotis discus hannai</Emphasis>

Ovarian follicle cells are the site of yolk protein synthesis in the Ezo abalone Haliotis discus hannai. In this study, histological observations of ovarian follicle cells were conducted in H. discus hannai by immunocytochemical and in situ hybridization methods focusing on their function of yolk protein synthesis. An antibody raised against purified yolk protein (vitellin, Vn) recognized yolk granules in oocytes, and ovarian follicle cells adjacent to the oocytes under yolk accumulation were stained positively with both anti-Vn antibody and an antisense probe for vitellogenin (the precursor for vitellin, Vtg) mRNA. These results indicate that the abalone Vtg gene is transcribed and translated in the ovarian follicle cells. In oocytes in the early phase of yolk accumulation, positive reactions with the antibody appeared first in the stalk part, and the follicle cells adjacent to the stalk were also stained positively. These observations imply local transport of yolk protein from the follicle cells to the oocyte through an extracellular space around the oocyte stalk. Ovarian follicle cells changed their morphological characteristics and reactivity to the antibody in close relation to the stages of the adjacent oocyte, which suggests the presence of functional interactions between follicle cells and oocytes in the course of yolk protein synthesis and accumulation.     

Origin and nature of halloysite in Ando soils from Towada tephra,Japan

The origin and nature of halloysite in Ando soils from Towada tephra were investigated. These soils were formed from five tephras: Towada-a (1,000 years old), Towada-b (2,000 years old), Chuseri (4,000 years old), Nanbu (8,600 years old) and Ninokura (10,000 years old).Formation of halloysite took place only in the buried soils from Nanbu and Ninokura tephras occurring in an “accumulating zone”, where thicknesses of overburden tephra deposits were mostly 2.5 m or greater and silica enrichment of the clay fractions could occur.The amounts of halloysite were greater in (1) the soils from Ninokura tephra than in those from Nanbu tephra, and greater in (2) the humus horizons as compared to the nonhumus horizons of these same soils. The mean sizes of spheroidal halloysite particles and the ratios of numbers of tubular to spheroidal forms differed with differences in soil horizons and age.High-resolution electron micrographs of glycerol-solvated spheroidal halloysite particles had lattice images of 11 Å due to (001) from the exterior to the interior and had no indications of layer separation. Moreover, the central core of spheroidal halloysite with a diameter of 150 Å showed neither layer structure nor allophane spherules.Results obtained in this study thus indicate that spheroidal and tubular forms of halloysite were formed concurrently in these Ando soils.     

New Rice Mutants（NR676 and NR827）Low in Nitrate Reduction

Mutants edficient in nitrate reductase(NR)were clasfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo-Co.This paper reports the characteristics of low NR mutants,which are not edficient in NRactivity but 40%-60%of the NRactivity of the wild type,Nipponbare.Mu-tants NR676and NR827 were selected as seedings showing poor growth with nitrate as sole mitrogen-source from M2 population.They exhibited chlorate reistance.Genetic analysis in the F1and F2indicated that chlo-rate resistance in the mutants was transmitted by a single recessive nuclear gene and that NR676 and NR827 were induced by a mutation at a single locus.In the F2population,all of the seedings showing yellow green leaves were resistant to chlorate and low in NRactivity,Photosynthetic rate and mRNA expression of NR676and NR827 were lower than wild type.These results suggested that low NR activity and chlorate resistance of NR676and NR827 were Caused by a defect in photosynthetic process.     

Estimation of the proportion of offspring having soluble solids content in fruit exceeding a given critical value in Japanese persimmon

In fruit breeding, the selection is often based on individual plant performance, therefore, the expected proportion of offspring having genotypic values exceeding a given critical value (EP) was estimated for soluble solids content (SSC) in Japanese persimmon (Diospyros kaki Thunb.). A simple model was used in the study: the mean value of offspring in a full-sib family is solely determined by the regression of that on midparental value (MP) and all families have an equal within-family variance due to segregation. The population consisted of 39 full-sib families with three offspring each. Between-family variance was much smaller than within-family variance. Genetic variance for MP was much smaller than that for offspring. The EP therefore was not highly affected by the regression. Based on the parental mean performance of 35 fruits on a single tree for three years, the proportion of offspring having SSC higher than 18% was estimated as 32%, 50% and 69% for three groups of MP differing in SSC, i.e. 16.5%, 17.5%, and 18.5%, respectively. The distributions which were predicted using those results for 246 offspring from 46 families, and 86, 44, 43 and 31 offspring from four selected families, respectively, were largely consistent with those observed.     

Geographical distribution of ribosomal DNA variation in taro, Colocasia esculenta (L.) Schott, in eastern Asia

Restriction fragment length polymorphism (RFLP) at the ribosomal RNA gene loci (rDNA) was investigated in 227 accessions of taro, Colocasia esculenta (L.) Schott, from China, Japan, Taiwan, and Vietnam. Eighteen different restriction fragment patterns of rDNA were observed. The results were largely consistent with a previous classification based on isozyme data. Some rDNA patterns were distributed extensively in the temperate zone from inland China to Japan. On the other hand, some other patterns ranged in coastal and/or insular areas from the tropical zone to the temperate zone (Japan). These geographical distributions may suggest two different routes for the introduction of taro into Japan: one from China,and the other most likely from Southeast Asia, via Taiwan and the Ryukyu Islands (southern Japan). This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization of CMS and maintainer lines in indica rice (Oryza sativa L.) based on RAPD marker analysis

Total DNA from WA type CMS lines: Zhenshan 97 A, Longtepu A and theirmaintainers Zhenshan 97 B, Longtepu B wasextracted by CTAB method. One hundredprimers were used for screening RAPDmarkers to distinguish CMS line (A) andmaintainer (B) plants at seedling stage.Results showed that under the conditions of37 ^°C annealing temperature and1.5 mM MgCl₂ concentration, in Zhenshan97 A, Longtepu A there was a 1600 bp DNAfragment in product amplified by primerOPA12, while in Zhenshan 97 B, and LongtepuB no 1600 bp fragment was found. The 1600 bpfragment was also found in DA type CMS lineXieqingzao A, but was absent in XieqingzaoB. Also in the restorer line, Minghui 63the 1600 bp fragment was absent. In F₁and F₂ generation of Zhenshan97A/Minghui 63, all plants investigated hadthe 1600 bp fragment. When mitochondrial DNA(mtDNA) was isolated from the three CMS (A)and their B lines and amplified by OPA12,results showed that the 1600 fragment wasfound in all the three A lines and wasabsent in the three B lines. In DA typeXieqingzao A, two other fragments (700 bp,1000 bp) were also found except the 1600 bp.These results indicate that the 1600 bpfragment derived from CMS mitochondrial DNAcan be used as a RAPD marker to distinguishA and B plants at seedling stage, and thefragments (700 bp, 1000 bp) can be used todistinguish WA and DA cytoplasms.     

线粒体DNA由来的RAPD标记能鉴别水稻雄性不育和可育细胞质

以野败型细胞质的水稻雄性不育系珍汕97A及其保持系珍汕97B的总DNA为模板,从100个引物中筛选到OPA12对珍汕97A能扩增出一条1600 bp的特异带.用OPA12扩增野败型细胞质的龙特浦A及其保持系龙特浦B、矮败型细胞质的协青早A及其保持系协青早B、恢复系明恢63、珍汕97A/明恢63的F1和F2个体的总DNA,不育系、F1和F2所有调查个体都有16     

Sensitivity of a Japanese Earthworm (Allolobophora Japonica) to Soil Acidity

Earthworms commonly dominate the soil fauna and they play important roles in terrestrial ecosystems, but their numbers decrease in acidic conditions. Their sensitivity to low pH was studied in Europe and their distributions were explained by their sensitivity. These kinds of studies have not been conducted in Japan. Sensitivity of a common Japanese earthworm, Allolobophora japonica, to acidified soils was studied. Worms withdrew its prostomium (oral organs) abruptly from Clark-Lubs buffer solutions of pH 3.9–4.1 when they were dipped into the solutions. The species did not burrow into soils of pH (H₂O) < 3.6 and died on and in the soils of pH (H₂O) < 4.0. It seemed that the species did not tolerate the soils of pH (H₂O) < 4.0. The responses to acid soil were almost same as those of European species. Soils should be maintained above pH 4 for this species.     

Dose assessment of 2% chlorhexidine acetate for canine superficial pyoderma

The dose of 2% chlorhexidine acetate (2CA; Nolvasan^® Surgical Scrub; Fort Dodge Animal Health, Fort Dodge, IA, USA) for canine superficial pyoderma was evaluated. The first trial compared three doses (group 1, 57 mL/m² body surface area; group 2, 29 mL/m² body surface area; and group 3, 19 mL/m² body surface area) in a randomized, double‐blind, controlled fashion. Twenty‐seven dogs with superficial pyoderma were treated with 2CA at the allocated doses every 2 days for 1 week. The owners and investigators subjectively evaluated the dogs, and investigators scored skin lesions, including erythema, papules/pustules, alopecia and scales, on a 0–4 scale. There were no significant differences in response between the treatment groups. The second trial established a practical dose‐measuring method for 2CA. Sixty‐eight owners were asked to apply 2CA on their palm in an amount corresponding to a Japanese ¥500 coin, 26.5 mm in diameter. This yielded an average dose of 0.90 ± 0.40 mL. Mathematically, the doses used in groups 1, 2 and 3 can be represented as one coin per approximately one‐, two‐ and three‐hand‐sized lesions, respectively. The results therefore suggest that owners instructed to apply one coin of the product per two‐hand‐sized areas of superficial pyoderma would use the range of doses evaluated in this trial.