Traditional seed production in landraces of daikon (Raphanus sativus) in Kyushu, Japan

Landraces of daikon, Japanese radish, Raphanus sativus var. hortensis, are grown and used traditionally in Kyushu, Japan. These landraces are maintained by seeds harvested from selected plants which are transplanted as dormant tap roots or are retained in a portion of field. Seeds kept in intact siliquas on the stems are harvested and stored until use, by hanging the dried stems. Although the relatively small number of plants used in a patch for seed production might be expected to result in a narrow base of genetic diversity of a farmers' lot in a landrace, addition of a few plants with contrasting features, pollen exchange between household patches, and contamination from other cultivars and feral forms may save the landraces from the rapid loss of diversity and deterioration caused by inbreeding depression. The seed production by transplanting described in medieval Japanese literature is relatively similar to the current practice. The factors responsible for maintenance of the landrace together with the cultural and climatic diversity of Japan may have contributed to a high diversity of landraces of the daikon. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chromospheric anemone jets as evidence of ubiquitous reconnection

The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection.     

A secondary symbiosis in progress?

Algae have acquired plastids by developing an endosymbiotic relationship with either a cyanobacterium (primary endosymbiosis) or other eukaryotic algae (secondary endosymbiosis). We report a protist, which we tentatively refer to as Hatena, that hosts an endosymbiotic green algal partner but inherits it unevenly. The endosymbiosis causes drastic morphological changes to both the symbiont and the host cell architecture. This type of life cycle, in which endosymbiont integration has only partially converted the host from predator to autotroph, may represent an early stage of plastid acquisition through secondary symbiosis.     

Epigenetic dynamics of imprinted X inactivation during early mouse development

The initiation of X-chromosome inactivation is thought to be tightly correlated with early differentiation events during mouse development. Here, we show that although initially active, the paternal X chromosome undergoes imprinted inactivation from the cleavage stages, well before cellular differentiation. A reversal of the inactive state, with a loss of epigenetic marks such as histone modifications and polycomb proteins, subsequently occurs in cells of the inner cell mass (ICM), which give rise to the embryo-proper in which random X inactivation is known to occur. This reveals the remarkable plasticity of the X-inactivation process during preimplantation development and underlines the importance of the ICM in global reprogramming of epigenetic marks in the early embryo.     

Nosological study of Borna disease virus infection in race horses.

To investigate the prevalence of diseases in the Borna disease virus (BDV) antibody positive race horses, we undertook seroepidemiological studies of BDV infection on 125 culled race horses in Hokkaido, Japan. The serological study disclosed the presence of antibodies only to BDV-p40 or -p24 in 19.2% (24/125) and 3.2% (4/125) of culled horses, respectively. Antibodies to both BDV-p40 and -p24 were found in 24.0% (30/125) of these horses. Of particular note was the finding that locomotorium disorders were detectable at a significantly higher rate in BDV antibody positive horses than that in the seronegative horses. These results imply that BDV infection may possibly contribute to an increase in the incidence rate of locomotorium disorders in race horses.     

脂肪酸添加剂抑制奶牛对环境污染的效果分析

将21头荷斯坦奶牛随机分为对照组和试验Ⅰ～Ⅵ组,每组3头,对照组饲喂TMR,试验Ⅰ～Ⅵ组饲喂TMR加50.0g、100.0g、150.0g、200.0g、250.0g、300.0g/头/d复合脂肪酸日粮.主要探讨复合脂肪酸对奶牛粪尿、N、P的排泄量和CH4释放量的影响.结果表明,TMR加150.0g/头/日～300.0g/头/d复合脂肪酸,比对照组CH4释放量减少11.40%～18.38%(P<0.01),粪尿和N及总P的排泄量分别降低1.38%～5.32%(P>0.05),11.84%～26.68%(P<0.01)和2.32%～4.86%(P>0.05),乳脂率提高10.76%～14.17%(P<0.05),有效抑制奶牛对周围土壤水源和空气的污染,显著提高奶牛的生态效益和经济效益.     

Differences in free amino acid composition between testis and ovary of sea urchin <Emphasis Type="Italic">Anthocidaris crassispina</Emphasis> during gonadal development

ABSTRACT:   For the purpose of clarifying the differences of taste components between the testis and ovary of the sea urchin Anthocidaris crassispina , variations in free amino acid composition in gonadal extract during gonadal development were investigated using chemical and histopathological methods. Sea urchins were collected at Iki Island, Nagasaki, Japan between 30 April and 5 June 2003, and maturation stages and the free amino acid compositions were determined. The sweet amino acids threonine (Thr), glycine (Gly), and alanine (Ala), the umami amino acid glutamic acid (Glu), and the bitter amino acids lysine (Lys) and arginine (Arg) were the main constituents accounting for more than 80% of total free amino acids. In the testis and ovary, Gly levels were the highest among them and increased with gonadal development. The other free amino acids consisted mainly of bitter amino acids and either showed no variation or decreased with gonadal development. These variations in free amino acid composition were observed more clearly in the ovary than the testis. These findings indicate the possibility of differences in the flavor of sea urchin gonad by sex and gonadal development stages.     

Food habits of small fishes in seagrass habitats in Trang,southern Thailand

To clarify the feeding habits of seagrass fishes, we examined the gut contents from 42 fish species collected in seagrass habitats in Trang. Thirteen species showed ontogenetic and/or seasonal changes in food-use patterns. Smaller individuals generally preyed on small planktonic items (e.g., copepod larvae) or small benthic/epiphytic crustaceans (e.g., harpacticoid copepods), with subsequent changes to other prey items (e.g., shrimps, crabs, detritus and filamentous algae) with growth. The most important dietary items for the seagrass fish assemblages comprised benthic/epiphytic crustaceans, detritus, and planktonic copepods. Cluster analysis based on dietary overlaps showed that the seagrass fishes comprised eight feeding guilds (large benthic/epiphytic crustacean, detritus, planktonic animal, small benthic/epiphytic crustacean, mollusc, invertebrate egg, polychaete, and fish feeders). Of these, the first three guilds were the most abundantly represented, whereas the last three were each represented by only a single species.