B220 is expressed on apoptotic thymocytes induced by X-irradiation.

CD45 is cell surface glycoprotein and expressed on all haematopoietic cells except mature erythrocytes and platelets. Eight isoforms of CD45 are generated by alternative splicing of exons 4-6. B220 including all three exons is expressed specifically on pan-B cell lineage. Recently, it was reported that B220 was expressed on apoptotic T cells induced by staphylococcal enterotoxin B (SEB). In the present study, we investigated the expression of B220 on murine thymocytes after whole-body X-irradiation. We used the forward light scattering of flow cytometry as a parameter of cell size, and defined two populations; FSChigh (normal cell size) and FSClow (correspond to apoptotic cell in size) fraction. B220+ cells in FSChigh fraction reached a maximum value (35%) at 18 hr after irradiation. In FSClow fraction, 40-60% cells were positive for B220 at any time points. These results suggest that B220 is expressed on thymocytes in the pre-apoptotic stage, because B220 was expressed on not only FSClow cells but also FSChigh cells.     

Immunoreactive changes in pituitary FSH and LH cells during seasonal reproductive and spawning cycles of female chub mackerel <Emphasis Type="Italic">Scomber japonicus</Emphasis>

The physiological functions of pituitary gonadotropins (GtHs) are well established in higher vertebrates, whereas those in teleosts are still poorly understood. To describe the role of GtHs during gonadal development of female chub mackerel Scomber japonicus, changes in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells were investigated immunohistochemically during the seasonal reproductive and spawning cycles. FSH and LH cells were identified in the different cell types of the proximal pars distalis (PPD); FSH cells were located in the central PPD, whereas LH cells were localized along the border of the pars intermedia. To examine changes in FSH and LH cells, the percentage of FSH or LH cell-occupying area in the PPD was evaluated and represented as FSHβ-immunoreactive (ir) or LHβ-ir levels, respectively. FSHβ-ir levels increased significantly from immature to the completion of vitellogenesis, whereas LHβ-ir levels were maintained at high levels from early vitellogenesis to post-spawning. During the spawning cycle, which consisted of four stages from just after spawning to the next oocyte maturation, both FSHβ-ir and LHβ-ir levels showed no significant changes among different stages; however, LHβ-ir levels remained relatively high, and FSHβ-ir levels were constantly low. These results suggest that both FSH and LH may be involved in vitellogenesis and LH may act at final oocyte maturation in female chub mackerel, although the role of FSH during the spawning cycle is still unclear.     

Lactation and digestion in dairy cows fed ensiled total mixed ration containing steam‐flaked or ground rice grain

The objective of this experiment was to investigate the effect of feeding ensiled total mixed ration (TMR) containing steam‐flaked (SF) or ground brown rice (Oryza satira L.; BR) on feed intake, lactation performance, digestion, ruminal fermentation and nitrogen (N) utilization in dairy cows. Eight multiparous Holstein cows were used in a crossover design with two dietary treatments: diets containing either SF or fine ground (FG) BR at 24% of dietary dry matter. Dietary treatment did not affect dry matter intake or milk yield and composition. The whole‐tract digestibility of organic matter and fiber decreased, and the digestibility of starch increased with the replacement of SF with FG in ensiled TMR, but these differences were small between diets. Crude protein digestibility was not different between diets. The processing method of BR did not affect ruminal pH, total volatile acid concentration, or volatile fatty acid proportion in cows. The N intake, milk N secretion, fecal and urinary N excretion and N retention were not influenced by dietary treatment. These results show that feeding ensiled TMR containing FG instead of SF reduces fiber digestibility but has little impact on lactation and N utilization when diets contained 24% on a dry matter basis.     

Two New Lyngbyatoxin Derivatives from the Cyanobacterium,Moorea producens

The toxin-producing cyanobacterium, Moorea producens, is a known causative organism of food poisoning and seaweed dermatitis (also known as “swimmer’s itch”). Two new toxic compounds were isolated and structurally elucidated from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies, as well as optical rotations and CD spectra indicated two new lyngbyatoxin derivatives, 2-oxo-3(R)-hydroxy-lyngbyatoxin A (1) and 2-oxo-3(R)-hydroxy-13-N-desmethyl-lyngbyatoxin A (2). The cytotoxicity and lethal activities of 1 and 2 were approximately 10- to 150-times less potent than lyngbyatoxin A. Additionally, the binding activities of 1 and 2 possessed 10,000-times lower affinity for the protein kinase Cδ (PKCδ)-C1B peptide when compared to lyngbyatoxin A. These findings suggest that these new lyngbyatoxin derivatives may mediate their acute toxicities through a non-PKC activation pathway.     

Mapping and validation of PCR-based markers associated with a major QTL for seed dormancy in wheat

Seed dormancy is one of the important factors controlling pre-harvest sprouting (PHS) resistance in wheat. We identified a major quantitative trait locus (QTL) for seed dormancy on the long arm of wheat chromosome 4A (4AL) via simple sequence repeat (SSR)-based genetic mapping using doubled haploid lines from a cross between Japanese PHS resistant variety ‘Kitamoe’ and the Alpine non-resistant variety “Münstertaler” (K/M). The QTL explained 43.3% of total phenotypic variation for seed dormancy under greenhouse conditions. SSR markers flanking the QTL were assigned to the chromosome long arm fraction length 0.59–0.66 on the basis of chromosome deletion analysis, suggesting that the gene(s) controlling seed dormancy are probably located within this region. Under greenhouse conditions, the QTL explained 28.5 and 39.0% of total phenotypic variation for seed dormancy in Haruyutaka/Leader (HT/L) and OS21-5/Haruyokoi (O/HK) populations, respectively. However, in field conditions, the effect was relatively low or not significant in both the K/M and HT/L populations. These markers were considered to be widely useful in common with various genetic backgrounds for improvement of seed dormancy through the use of marker-assisted selection. Further detailed research using near isogenic lines will be needed to define how this major QTL interacts with environmental conditions in our area.     

Mercury Speciation in the Water of Minamata Bay, Japan

The speciation of mercury (Hg) in Minamata Bay (Japan) was studied over a 2-year period (2006?C2008). Concentrations of dissolved total Hg, dissolved methylmercury (MeHg), particulate total Hg, and suspended solids were 0.43?±?0.14 ng/l (mean?±?standard deviation), 0.10?±?0.06 ng/l, 3.04?±?2.96 ng/l, and 5.94?±?2.10 mg/l, respectively. Correlations between concentrations of particulate total Hg and suspended solids at four depths (surface: 0 m; mid-depth: ?6 m, ?10 m; and bottom +1 m layer) were only significant in the bottom +1 m layer. The mean dissolved MeHg concentration and the ratio of dissolved MeHg to dissolved total Hg were considerably higher in summer compared to other seasons. The data suggest that bottom sediment was not the sole source of MeHg, and that MeHg may be produced in the water column by the conversion of divalent Hg eluted from resuspended bottom sediment. The correlation between seawater characteristics such as salinity, temperature, dissolved oxygen (DO), and dissolved MeHg concentration indicates that Hg methylation could be influenced by the heterotrophic activity of microorganisms in the seawater. In particular, inverse correlations were observed between DO, salinity, and MeHg concentration. However, dissolved MeHg concentrations did not correlate with seawater characteristics such as pH or chlorophyll-a.     

Bi-directional sex change and its steroidogenesis in the wrasse, Pseudolabrus sieboldi

The protogynous wrasse, Pseudolabrus sieboldi, is a good model for studying the physiological mechanism of sex change in teleosts. We established a way to induce sex change bidirectionally by controlling the social conditions in captivity. This is the first report of a reversed sex change in a promiscuous species. After identifying all the steroid hormones produced in the ovarian follicles and testis, and clarifying their synthetic pathways, we examined the function of the sex steroids in the sex change of P. sieboldi. We concluded that the activation of 17β-HSD-III is the first step in inducing morphological and functional change from an ovary to a testis.     

Solubilization of type I and V collagens in Japanese flounder muscle during chilled storage

ABSTRACT:   The post-mortem changes of type I and V collagens in Japanese flounder muscle during chilled storage were examined. The muscle softened significantly within 12 h under chilled storage. Both type I and V collagens isolated by ion-exchange chromatographies showed no remarkable changes in band patterns even after 24 h of storage, suggesting that degraded collagen molecules may be removed from the collagen fraction by a conventional preparation method. In contrast, type I and V collagen molecules were detected by Western blotting with each specific antibody in a saline extract and gradually increased during chilled storage. These results suggest that both type I and V collagens may participate in the post-mortem softening of fish muscle.     

Evaluation of the bioactivities of water-soluble extracts from twelve deep-sea jellyfish species

Many polypeptides isolated from shallow water cnidarian species have been utilized as valuable biochemical tools in both basic and applied biological sciences. Deepwater cnidarian species might be another potential resource for novel biochemical tools. However, because of limited access to cnidarian samples from deep-sea environments, bioactive polypeptides have never before been reported from this group. In this study, we collected twelve deep-sea jellyfish species (nine hydrozoans and three scyphozoans) using a plankton net that was specially designed for collecting deep-sea organisms, and prepared water-soluble extracts, presumably containing polypeptides, of these jellyfishes. The extracts were subjected to cytotoxicity, hemolytic activity, and crustacean lethal toxicity tests. In the cytotoxicity test, six out of the nine tested hydrozoan species showed activity. In the hemolytic activity test, only three hydrozoans showed activity and none of the scyphozoan jellyfishes showed activity. In the crustacean lethality test, two hydrozoan jellyfishes and all three of the tested scyphozoan jellyfishes showed lethal activity. These results revealed a high incidence of water-soluble bioactive substances occurring in these deep-sea jellyfishes. Furthermore, all the heat-treated and the methanol-treated crude jellyfish extracts lost their bioactivities. Thus, it is likely that the bioactive compounds in the water-soluble extracts were unstable polypeptides (proteins). This is the first published report on bioactivities in extracts from deep-sea jellyfishes.