Gonadal sex differentiation in protandrous anemone fish, Amphiprion clarkii

To clarify the process of sex differentiation in protandrous anemone fish, histological structure of their gonads was examined from 1 day to 214 days after hatching (dah). Gonadal development was first characterized by differentiation of ovarian tissues at 61 dah, followed by interspersed appearance of testicular tissues in the ovary at 214 dah.     

A genetic linkage map of rhodesgrass based on an F1 pseudo-testcross population

The linkage relationships between 164 polymorphic amplified fragment length polymorphism (AFLP) and 25 restriction fragment length polymorphism (RFLP) fragments assayed in a pseudo‐testcross population generated from the mating of single genotypes from two divergent cultivars were used to construct female, ‘Katambora’ (‘Kat’) and male, ‘Tochirakukei’ (‘Toch’) parental genetic maps for rhodesgrass. The ‘Kat’ genetic map consists of 84 marker loci (72 AFLP and 12 RFLP markers) distributed on 14 linkage groups and spans a total length of 488.3 cM, with an average distance of 7.8 cM between adjacent markers. The ‘Toch’ genetic map consists of 61 marker loci (52 AFLP and nine RFLP) mapped on 12 linkage groups spanning a total length of 443.3 cM, with an average spacing of 9.0 cM between adjacent markers. About 23% of the markers remained unassigned. The level of segregation distortion observed in this cross was 11.1%. In both maps, linked duplicated RFLP loci were found. These linkage maps will serve as a starting point for linkage studies in rhodesgrass with potential application for marker‐assisted selection in breeding programmes.     

Identification and quantification of the conjugated metabolites derived from orally administered hesperidin in rat plasma

Hesperidin is a biologically effective flavonoid. Several studies have reported that dietary hesperidin was converted to conjugated metabolites, such as hesperetin-glucuronides and sulfoglucuronides, during absorption and metabolism. However, the chemical structures of the conjugated metabolites, especially the sites of glucuronidation and sulfoglucuronidation in plasma, were unconfirmed. Therefore, the concentrations of the metabolites conjugated at various sites in plasma could not be individually quantified. In the present study, we identified the chemical structures and concentrations of the major conjugated metabolites in rat plasma after oral administration of hesperidin. Two hesperetin-glucuronides were prepared and identified as hesperetin-7-O-beta-D-glucuronide and hesperetin-3'-O-beta-D-glucuronide. Using these authentic compounds, the concentrations of hesperetin-7-O-beta-D-glucuronide and hesperetin-3'-O-beta-D-glucuronide in rat plasma were individually determined by liquid chromatography-mass spectrometry. In rat plasma, hesperetin-glucuronides were primarily comprised of hesperetin-7-O-beta-D-glucuronide and hesperetin-3'-O-beta-D-glucuronide. The concentration of hesperetin-7-O-beta-D-glucuronide was slightly higher than that of hesperetin-3'-O-beta-D-glucuronide. Furthermore, not only hesperetin conjugates but also homoeriodictyol conjugates were observed in rat plasma. The present study is the first report elucidating the chemical structures and changes in individual concentrations in rat plasma of glucuronides derived from orally administered hesperidin.     

Reactivity and prevalence of neutralizing antibodies against Japanese strains of bovine viral diarrhea virus subgenotypes

Bovine viral diarrhea virus (BVDV) field isolates show genetic and antigenic diversity. At least 14 subgenotypes of BVDV-1 and 4 of BVDV-2 have been identified in Artiodactyla worldwide. Of these, 6 subgenotypes of BVDV-1 and 1 of BVDV-2 have been isolated in Japan. Previously, we reported that each subgenotype virus expresses different antigenic characteristics. Here we investigated the reactivity of neutralizing antibodies against representative strains of Japanese BVDV subgenotypes using sera from 266 beef cattle to estimate the prevalence of this epidemic virus among cattle in Japan. Antibody titers at concentrations at least 4-fold higher than antibodies against other subgenotype viruses were considered subgenotype specific. Subgenotype-specific antibodies were detected from 117 (80.7%) of 145 sera samples (69.7% against BVDV-1a, 1.4% against BVDV-1b, 8.3% against BVDV-1c, and 1.4% against BVDV-2a). The results suggest that neutralization tests are useful in estimating currently epidemic subgenotypes of BVDV in the field.     

Development of an acid soil conditioning agent from lignin by ozone treatment III: improvement of ability of lignin to form an aluminum complex and to reduce aluminum toxicity after ozone treatment

Lignin prepared by a modified Klason method (KSL) was modified with ozone followed by alkaline treatments. The original and modified KSLs were subjected to a plant growth test with radish (Raphanus sativus L. var. radicula Pers.) in the presence of AlCl₃ (37.5 μM) to assess their ability to reduce aluminum toxicity. The formation of an aluminum complex with these KSLs was also examined by potentiometry. Neither the original nor alkaline-treated KSLs had an effect on aluminum toxicity or the formation of a complex, except for the alkaline-treated KSL at a maximal dose of 250 mg/l, which reduced aluminum toxicity. However, all the KSLs modified with ozone and alkali were effective at forming a complex and reducing aluminum toxicity. The dose of saponified ozone-treated KSLs required to reduce aluminum toxicity became lower and their water solubility increased as the ozone treatment was prolonged. These findings clearly show that water solubility and the ability to form a complex with and reduce the toxicity of aluminum were improved by ozone treatment of KSL.     

A new proposal to reinforce planked timber shear walls

Timber is one of the most common materials used in traditional buildings worldwide. Our previous research has suggested that timber shear walls play an important role in resisting external loadings, such as earthquakes. Thus, improving the structural performance of in-filled shear walls can also improve that of the entire structure. In the traditional Taiwanese timber shear wall system, the embedment strength of beams and friction between wooden planks and beams significantly affect the strength of the shear wall. This article proposes a new method of reinforcing traditional timber shear walls in Taiwan by inserting teak and padauk strips into the grooves between wooden planks and beams to increase the embedment strength of beams and the friction between wooden planks and the hardwood strips. A total of 18 full-scale specimens were tested under reversed cyclic loading. The results revealed that the strength and energy dissipation capacities of a wooden shear wall can be significantly increased by inserting teak and padauk strips into the grooves between planks and beams. Furthermore, the simplified calculation method proposed in this study can be used to calculate the strength of both reinforced and unreinforced wooden shear walls with satisfactory agreement.     

长江三峡花岗岩坡面土管空间分布特征

为深入研究土管的空间分布对土壤水分运动的影响 ,该研究在长江三峡花岗岩坡面选择了一受人为活动影响较小的天然次生马尾松林地作为试验场地 ,开挖土壤剖面 ,观测并研究了其土管空间分布特性 .研究结果表明土管主要分布在距地表以下 0 8～ 1 0m范围内 ,经Iδ 指数检验其分布类型为聚集分布型 .据调查并推断其土管成因主要为土壤形成作用和动物活动或植物根系腐烂后形成的根孔所致     

Antigenic variation and resistance to neutralization in poliovirus type 1

Mutations have been identified in variants of poliovirus, type 1 (Mahoney) on the basis of their resistance to neutralization by individual monoclonal antibodies. The phenotypes of these variants were defined in terms of antibody binding; the pattern of epitopes expressed or able to be exploited for neutralization were complex. Single amino acid changes can have distant (in terms of linear sequence) and generalized effects on the antigenic structure of poliovirus and similarly constituted virions.     

Genetic diversity and spatial distribution of rhizobial bacteria nodulating on black locust (Robinia pseudoacacia) rhizospheres

Black locust (Robinia pseudoacacia L.) is an economically and ecologically important tree in Japan. The species is widely used for afforestation because of its symbiotic relationship with nitrogen-fixing rhizobia. In this study, genetic diversity of rhizobia isolated from black locust nodules and spatial distribution of their genotypes were examined. From a coastal forest, six black locust saplings including the whole root systems were collected and positions of nodules on the roots were recorded. Bacteria were isolated from each nodule and then genotyped by Polymerase Chain Reaction (PCR)-Restriction Fragment Length Polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. Dendrogram analysis based on PCR-RFLP and sequencing analysis indicated that Mesorhizobium species dominantly colonized black locust roots in this forest, occupying at least 77% of living nodules. Positions and PCR-RFLP genotypes of the nodules revealed that rhizobia isolated from neighbouring nodules tended to have the same genotype in some cases. Statistical analysis has supported this fact. The clustering distribution of nodules in the same RFLP groups should be considered to contribute to the large genetic diversity of rhizobia.