Korean species of the genus Bisnius Stephens (Coleoptera: Staphylinidae)

Two Korean species of the genus Bisnius Stephens are studied. Bisnius macies (Sharp), found along the seashore of some islands, is introduced for the first time in Korea.     

Eleven new highly polymorphic microsatellite loci in the yellow croaker,Pseudosciaena crocea

We developed 11 new microsatellite markers in Pseudosciaena crocea by screening an enriched genomic library using nonradioactive polymerase chain reaction (PCR) techniques. All loci were found to be polymorphic with an average of 14.9 alleles per locus (range four to 30). The mean observed and expected heterozygosities were 0.86 (range 0.57–1.00) and 0.90 (range 0.62–0.98), respectively. Four loci showed significant Hardy–Weinberg disequilibrium. The high variabilities revealed in this study suggest that these microsatellite loci should provide useful markers for population genetic studies of P. crocea.     

Multiple determinants influence root colonization and induction of induced systemic resistance by Pseudomonas chlororaphis O6

Colonization of the roots of tobacco by Pseudomonas chlororaphis O6 induces systemic resistance to the soft-rot pathogen, Erwinia carotovora ssp. carotovara SCC1. A screen of the transposon mutants of P. chlororaphis O6 showed mutants with about a fivefold reduction in ability to induce systemic resistance to the soft-rot disease. These mutations disrupted genes involved in diverse functions: a methyl-accepting chemotaxis protein, biosynthesis of purines, phospholipase C, transport of branched-chain amino acids and an ABC transporter. Additional mutations were detected in the intergenic spacer regions between genes encoding a GGDEF protein and fumarate dehydratase, and in genes of unknown function. The mutants in the ABC transporters did not display reduced root colonization. However, the other mutants had up to 100-fold reduced colonization levels. Generally the production of metabolites important for interactions in the rhizosphere, phenazines and siderophores, was not altered by the mutations. A reduced induction of systemic resistance by a purine biosynthesis mutant with a disrupted purM gene correlated with poor growth rate, lesser production of phenazines and siderophore and low levels of root colonization. These studies showed that multiple determinants are involved in the induction of systemic resistance, with there being a requirement for strong root colonization.     

Morphology and Molecular Phylogeny of Trimyema koreanum n. sp., a Ciliate from the Hypersaline Water of a Solar Saltern

ABSTRACT. A new ciliate, Trimyema koreanum n. sp., isolated from hypersaline water (salinity of 293‰) from a solar saltern in Korea, was investigated using live observation, protargol impregnation, and gene sequencing. Trimyema koreanum is about 30 × 13 μm in vivo, has usually 23 longitudinal ciliary rows forming two distinct ciliary girdles visible both in vivo and in protargol impregnation. A third indistinct ciliary girdle as well as a girdle of mucocysts is distinguishable only in impregnated cells. We suggest T. koreanum as a new species, differing from the most similar species, T. marinum, by the presence of two distinct ciliary girdles (T. marinum usually has six ciliary girdles clearly visible in living cells and three anterior spirals that encircle the cell completely). Although the number of known 18S rRNA sequences in the genus Trimyema was limited, the Trimyema group including T. koreanum forms a strong clade. The phylogenetic position confirms that the isolate belongs to the genus Trimyema and is different from previously sequenced species. Trimyema koreanum is able to consume both prokaryotes and small eukaryotes (specifically, the alga Dunaliella sp.).     

Different phylogeographic patterns in two Japanese Silpha species (Coleoptera: Silphidae) affected by climatic gradients and topography

To reveal differences in phylogeographic patterns of flightless insect species occurring in different regions of Japan, we studied the phylogeography and demographic history of Silpha beetles occurring in cool-temperate habitats of two major islands, Honshu and Hokkaido, using sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene. Honshu has a more mountainous topography, and cool-temperate habitats occur discontinuously, whereas Hokkaido, located to the north of Honshu, has more continuous cool-temperate habitats. A species endemic to Honshu, S. longicornis occurs on Honshu, whereas S. perforata occurs on Hokkaido and the East Asian continent. Our results indicate that the ancestors of S. longicornis colonized Honshu via a south-west route c . 0.7 Mya and the species has highly divergent populations in isolated mountainous areas of Honshu, whereas S. perforata colonized Hokkaido via a northern route less than 90 000 years ago and has less divergent geographic populations. During the last glacial period, S. perforata was probably restricted to refugia in southern Hokkaido and later expanded into northern Hokkaido, whereas S. longicornis populations existed in many isolated refugia, probably because of the complex topography of Honshu. Thus, our study demonstrates that, even between closely related species, interactions among biology, latitudinal climatic gradients and topography can produce different phylogeographic patterns.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 452–467.     

Ceramide Inhibits Cell Proliferation through Akt/PKB Inactivation and Decreases Melanin Synthesis in Mel‐Ab Cells

Ceramide is a bioactive sphingolipid that mediates a variety of cell functions. However, the effects of ceramide on cell growth and the melanogenesis of melanocytes are not known. In the present study, we investigated the actions of cell‐permeable ceramide and its possible role in the signaling pathway of a spontaneously immortalized mouse melanocyte cell line, Mel‐Ab. Our results show that C₂‐ceramide inhibits DNA synthesis in Mel‐Ab cells and G361 human melanoma cells in a dose‐dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase. To investigate the ceramide signaling pathway, we studied whether C₂‐ceramide is able to influence extracellular signal‐regulated kinase (ERK) and/or Akt/protein kinase B (PKB) activation. We demonstrated that phosphorylated Akt/PKB is decreased by C₂‐ceramide, whereas phosphorylated ERK was only slightly affected. Therefore, the C₂‐ceramide‐induced inactivation of Akt/PKB may be closely related to the reduced cell proliferation of Mel‐Ab cells. Furthermore, we assessed the effects of C₂‐ceramide on the pigmentation of Mel‐Ab cells. The results obtained showed that the melanin content of cells was significantly reduced by C₂‐ceramide at concentrations in the range of 1–10 μM, and that the pigmentation‐inhibiting effect of C₂‐ceramide is much greater than that of kojic acid at 1–100 μM. In addition, we found that the activity of tyrosinase is reduced by C₂‐ceramide treatment. Our results demonstrate that C₂‐ceramide reduces the pigmentation of Mel‐Ab cells by inhibiting tyrosinase activity.     

Cold hardiness in the black rice bug, Scotinophara lurida

Abstract.  The mechanisms and strategies for winter survival of the black rice bug Scotinophara lurida are investigated along with the relationship between cold hardiness and diapause. The ability of S. lurida to survive subzero temperatures varies depending on developmental stage, temperature and exposure duration. Mean supercooling point (SCP) varies from –7.6 to –10.7 °C with developmental stage, but is not significantly different between stages examined. The SCP also varies with season, being lowest in January and increasing rapidly in February and remaining almost at the same level (–7.3 to 9.6 °C) until April The osmolality of haemolymph of field-collected S. lurida adults rises dramatically from 53.9 mOsm kg⁻¹ in August to 75.3 mOsm kg⁻¹ in December, and then declines linearly to 57.0 mOsm kg⁻¹ in May. Field-collected S. lurida adults show a peak glucose content in October, glycerol content in November and trehalose content in December. Only trehalose content decreases after the application of the juvenile hormone analogue, fenoxycarb, suggesting that trehalose is a cryoprotectant during diapause. These various physiological and biochemical traits related to cold tolerance in S. lurida may be, at least in part, under the control of juvenile hormone through the reproductive diapause programme.     

Ecological and morphological characteristics of the endoparasitoids of larval Acronicta rumicis (Lepidoptera: Noctuidae)

The Hymenopterans Glyptapanteles liparidis, Microplitis sp. and Diadegma sp. were found to be larval parasitoids and koinobionts of Acronicta rumicis (Lepidoptera: Noctuidae). Mesochorus semirufus is believed to be a new unreported hyperparasitoid of G. liparidis, which, along with M. semirufus, is a gregarious parasitoid. In contrast, the parasitoids Microplitis sp. and Diadegma sp. are solitary. All of the hymenopteran parasitoids are multivoltine insects that emerge from A. rumicis more than once. Compcilura concinnata, Euexorista sp. and Exorista sp. of the Diptera were found to be larval–pupal parasitoids, solitary parasitoids and koinobionts. These three species are univoltine, and emerge only once from A. rumicis. Morphological and life cycle data were collected for G. liparidis, and for the parasitoids of that species found in this study. The major and minor axes of an egg of G. liparidis were 0.10 and 0.02 mm, respectively, while the mean clutch size of G. liparidis was 67.71 ± 39.36 individuals. The body length of female and male G. liparidis were 2.25 ± 0.06 and 2.21 ± 0.12 mm, respectively, and the longevity of an adult was 2.93 ± 0.96 days. Among the parasitoids, the mean body length of an adult Microplitis sp. was 3.5 mm and adults lived for an average of 8.13 ± 3.54 days. The adult Diadegma sp. was larger (mean body length 6.5 mm) but lived for a shorter interval (3.33 ± 1.32 days). The body lengths of female and male M. semirufus were 3.16 ± 0.11 and 3.10 ± 0.23 mm, respectively, greater than the body lengths of female and male G. liparidis. The body lengths of adult C. concinnata, Euexorista sp. and Exorista sp. were 9.5, 9.53 and 8.68 mm, respectively. All of their pupae were dark brown.