An estuarine neritid gastropod, Clithon corona, a potential reservoir of thermostable direct hemolysin-producing Vibrio parahaemolyticus

An estuarine neritid gastropod, Clithon corona, maintained in UV-irradiated recirculating artificial seawater with a salinity of 15 per mil (%o) was found to retain thermostable direct hemolysin (TDH)-producing Vibrio parahaemolyticus in the gut at significantly higher levels than TDH-non-producing one for at least 14 days. Another estuarine neritid gastropod, C. sowerbianus, was not able to support the preferential survival of TDH-producing organisms. This evidence suggests that, if TDH-producing vibrios are brought to estuaries inhabited by C. corona, repeated ingestion of V. parahaemolyticus by this gastropod could lead to accumulation of TDH-producing vibrios in the estuaries.     

Deformation of (Mg,Fe)SiO3 post-perovskite and D' anisotropy

Polycrystalline (Mg(0.9),Fe(0.1))SiO3 post-perovskite was plastically deformed in the diamond anvil cell between 145 and 157 gigapascals. The lattice-preferred orientations obtained in the sample suggest that slip on planes near (100) and (110) dominate plastic deformation under these conditions. Assuming similar behavior at lower mantle conditions, we simulated plastic strains and the contribution of post-perovskite to anisotropy in the D' region at the Earth core-mantle boundary using numerical convection and viscoplastic polycrystal plasticity models. We find a significant depth dependence of the anisotropy that only develops near and beyond the turning point of a downwelling slab. Our calculated anisotropies are strongly dependent on the choice of elastic moduli and remain hard to reconcile with seismic observations.     

First record of avian Plasmodium DNA from mosquitoes collected in the Yaeyama Archipelago, southwestern border of Japan

We studied the prevalence of avian Plasmodium in 509 mosquitoes of 9 species collected from the Ishigaki and Iriomote islands in the Yaeyama Archipelago, located southwest from the mainland of Japan. Two identical avian Plasmodium lineages were detected from Culex (Culiciomyia) nigropunctatus. Detected lineages were phylogenetically classified into different clade to avian Plasmodium lineages from birds and mosquitoes in the mainland of Japan but identical to a lineage detected from a resident bird, White-breasted Waterken (Amaurornis phoenicurus). This is the first detection of avian Plasmodium DNA from mosquitoes in the Yaeyama Archipelago and suggested that resident birds might have been infected with an avian Plasmodium lineage specific to the studied area and C. nigropunctatus could be the candidate vector mosquito species.     

Advanced backcross QTL analysis reveals complicated genetic control of rice grain shape in a japonica × indica cross

Grain shape is an important trait for improving rice yield. A number of quantitative trait loci (QTLs) for this trait have been identified by using primary F₂ mapping populations and recombinant inbred lines, in which QTLs with a small effect are harder to detect than they would be in advanced generations. In this study, we developed two advanced mapping populations (chromosome segment substitution lines [CSSLs] and BC₄F₂ lines consisting of more than 2000 individuals) in the genetic backgrounds of two improved cultivars: a japonica cultivar (Koshihikari) with short, round grains, and an indica cultivar (IR64) with long, slender grains. We compared the ability of these materials to reveal QTLs for grain shape with that of an F₂ population. Only 8 QTLs for grain length or grain width were detected in the F₂ population, versus 47 in the CSSL population and 65 in the BC₄F₂ population. These results strongly suggest that advanced mapping populations can reveal QTLs for agronomic traits under complicated genetic control, and that DNA markers linked with the QTLs are useful for choosing superior allelic combinations to enhance grain shape in the Koshihikari and IR64 genetic backgrounds.     

Slip systems in MgSiO3 post-perovskite: implications for D' anisotropy

Understanding deformation of mineral phases in the lowermost mantle is important for interpreting seismic anisotropy in Earth's interior. Recently, there has been considerable controversy regarding deformation-induced slip in MgSiO(3) post-perovskite. Here, we observe that (001) lattice planes are oriented at high angles to the compression direction immediately after transformation and before deformation. Upon compression from 148 gigapascals (GPa) to 185 GPa, this preferred orientation more than doubles in strength, implying slip on (001) lattice planes. This contrasts with a previous experiment that recorded preferred orientation likely generated during the phase transformation rather than deformation. If we use our results to model deformation and anisotropy development in the D' region of the lower mantle, shear-wave splitting (characterized by fast horizontally polarized shear waves) is consistent with seismic observations.     

The effect of isoprothiolane on the emergence of infection pegs from appressoria of Pyricularia oryzae

The effect of isoprothiolane^a (di-isopropyl 1,3-dithiolan-2-ylidenemalonate), a systemic fungicide used for rice blast control, on the infection process of Pyriculuria oryzae was studied by micromanipulation in a scanning electron microscope. Whether or not infection pegs emerged from the appressoria was examined by inverting each appressorium contact surface. Infection pegs were observed on more than 80% of the appressoria, 48 h after inoculation, on both untreated rice leaves and cellophane film. Isoprothiolane, approximately 10 μg ml^?1 in the ambient water of inoculated conidia, reduced the emergence of infection pegs on rice leaves and cellophane film by 96 and 100%, respectively.