QTL Analysis for Traits Associated with Feeding Value of Straw in Rice(Oryza sativa L.)

Genetic improvement of the digestibility of rice strew for increasing the utilization of the whole rice plant as feedstuffs is an important way to solve the feedstuffs shortage in southeastem China. To elucidate the genetic basis of the traits affecting the digestibility of rice straw, a rice population of 111 recombinant inbred lines (RILs) derived from a cross of Nekken 2xGaya was used to map the quantitative traits loci (QTLs) for in vitro dry matter digestion (IVDMD), the percentages of nonstructurel carbohydrate (NSC) and acid detergent fiber (exclusive of residual ash, ADFom) in 2005 and 2006. IVDMD was positively correlated with NSC, and negatively correlated with ADFom. A total of 16 QTLs were detected in the two years, and the amounts of variation explained by individual QTLs ranged from 6.9% to 15.5%. Some QTLs for IVDMD and ADFom on chromosome 2 were detected in the two years. On chromosome 2, the interval RM475-RM3515 contained QTLs for IVDMD in the two years and for NSC in 2006 only, while the interval RM3874-RM5305 influenced ADFom in the two years and NSC in 2005 only. At those loci, Gaya contributed favorable alleles to IVDMD and NSC, while Nekken 2 contributed positive alleles to ADFom.     

Use of microsatellite DNA and amplified fragment length polymorphism for Cherry salmon (Oncorhynchus masou) complex identification

Formosa landlocked salmon (Oncorhynchus masou formosanus), an endemic, critically endangered subspecies of Cherry salmon (Oncorhynchus masou) complex, is only found in Taiwan. Because the eyed eggs and ungutted carcasses of Pacific salmons (genus Oncorhynchus) are imported for aquaculture and food to Taiwan from overseas every year, the requirement for preventing illegal trade or accidental commercial imports to avoid unwanted fish from contaminating the gene pool of Formosa landlocked salmon and infect them with diseases is critical for the conservation of Formosa landlocked salmon. Traditional morphology‐based species identification is impossible for salmon eggs and larvae that lack clearly defined morphological features. In the present study, the genetic differences among four subspecies (Oncorhynchus masou ishikawae, O. masou subsp., Oncorhynchus masou masou and O. masou formosanus) of Cherry salmon complex were determined from microsatellite DNA and amplified fragment length polymorphism analyses. We successfully generated a genetic marker to aid traditional taxonomy and investigate the integrity of the current taxonomic status among members of Cherry salmon complex. Use of molecular markers, in combination with traditional morphological identification, is a promising tool for identifying four closely related subspecies of Cherry salmon complex.     

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.     

Phenotypic variation in root development of 162 soybean accessions under hypoxia condition at the seedling stage

Soybean is often damaged by hypoxia caused by waterlogging at the seedling stage. Hypoxia severely inhibits root development and retards plant growth. We aimed to clarify phenotypic variation in root development under hypoxia condition at the seedling stage using diverse soybean accessions. Root development in 162 accessions was evaluated in hydroponic culture. Substantial changes under hypoxia were investigated by means of WinRHIZO analysis before and after the treatment. We found significant phenotypic variation in hypoxia tolerance in root among the 162 accessions. A principal components analysis indicated an association between hypoxia tolerance and the country of origin. We found three new accessions which have a high ability to develop roots under hypoxia (Kokubu 7, Maetsue zairai 90B, and Yahagi). Root development in selected accessions was also evaluated in soil culture. Root development levels in hydroponic and soil culture were significantly correlated. These results will provide important information on waterlogging damage in regions where waterlogging occurs. The three accessions with hypoxia-tolerant roots might be useful for genetic improvement of waterlogging tolerance of modern soybean varieties.     

Molecular cloning of canine Mcl-1 gene and its expression in tumor cell lines

The canine Mcl-1 gene was cloned and sequenced. Canine Mcl-1 clone was 2694 base pairs in length and encoded 350 amino acids. The predicted amino acid sequence was 87.7%, 77.1% and 75.7% homologous to predicted human, mouse and rat Mcl-1, respectively. RT-PCR analysis revealed that canine Mcl-1 mRNA was expressed in PBMCs (peripheral blood mononuclear cells), bone marrow cells, MDCK (Madin-Darby canine kidney) and GL-1 (canine B cell leukemia) whereas undetectable in CL-1 (canine T cell lymphoma) cell line.     

The mechanism by which mouse spermatozoa are injured during freezing

To improve the cryopreservation protocol for mouse sperm, we attempted to estimate the type and extent of cryoinjury at various steps of the process. First, we demonstrated that mouse sperm are sensitive to chilling at -15 C and that the sensitivity is dependent on the length of exposure. To estimate cryoinjuries, sperm suspensions were ice-seeded at -5 or -15 C, frozen with liquid nitrogen (LN(2)) gas and then frozen in LN(2). In one experiment, sperm seeded at -5 C were cooled slowly to -15 C before deep freezing. At various steps of the cryopreservation process, the sperm were warmed and their viability was assessed based on motility and the integrities of the plasma membrane and acrosome. The motility of frozen-thawed sperm was higher on seeding at -5 C (28%) than at -15 C (9%). The motility did not decrease when the sample was transferred from LN(2) gas to LN(2). To estimate cryoinjury of sperm, we presumed the viability of frozen sperm to be decreased by chilling, hypertonic stress and formation of intracellular ice. When the sperm suspension was cooled and seeded at -5 C, the motility decreased by 25% due to hypertonic stress. When the sperm were cooled in LN(2) gas, the motility decreased by 17% with the formation of intracellular ice. When the sperm were cooled to -15 C, the motility decreased by 51% from chilling. After seeding, the motility decreased by 18% due to formation of intracellular ice and by 7% due to hypertonic stress. Considering the results, it would be preferable to seed samples at a higher temperature to prevent intracellular ice from forming and to cool seeded samples rapidly enough to minimize chilling injury and hypertonic stress, but not too rapidly to allow intracellular ice to form.     

A single injection of periostin decreases cardiac voltage-gated Na+ channel in rat ventricles

Changes in electrophysiological properties, such as ion channel expression and activity, are closely related to arrhythmogenesis during heart failure (HF). However, a causative factor for the electrical remodeling in HF has not been determined. Periostin (POSTN), a matricellular protein, is increased in heart tissues of patients with HF. In the present study, we investigated whether a single injection of POSTN affects the electrophysiological properties in rat ventricles. After male Wistar rats were intravenously injected with recombinant rat POSTN (64 µg/kg, 24 hr), electrocardiogram (ECG) was recorded. Whole-cell patch clamp was performed to measure action potential (AP) and Na⁺ current (I_Na) in isolated ventricular myocytes. Protein expression of cardiac voltage-gated Na⁺ channel (Na_V1.5) in isolated ventricles was examined by Western blotting. In ECG, POSTN-injection significantly increased RS height. POSTN-injection significantly delayed time to peak in AP and decreased I_Na in the isolated ventricular myocytes. POSTN-injection decreased Na_V1.5 expression in the isolated ventricles. It was confirmed that POSTN (1 µg/ml, 24 hr) decreased I_Na and Na_V1.5 protein expression in neonatal rat ventricular myocytes. This study for the first time demonstrated that a single injection of POSTN in rats decreased I_Na by suppressing Na_V1.5 expression in the ventricular myocytes, which was accompanied by a prolongation of time to peak in AP and an increase of RS height in ECG.     

Leaf spot of barnyardgrass caused by Exserohilum oryzicola in Japan and the fungal influence on rice,barley, bread wheat,durum wheat,and soybean

Journal of General Plant Pathology - Brown lesions were found on leaves of the weed barnyardgrass in paddy fields in Hiroshima Prefecture in western Japan in June 2017. A fungus, isolated...