The genetic structure of Aphis gossypii populations in Japanese fruit orchards

The genetic structure of Aphis gossypii Glover (Hemiptera: Aphididae) populations was characterized using microsatellite analysis of insects sampled from pear and citrus orchards at three locations in the summer seasons of 2001 and 2003. These data will enable more precise forecasting of infestation and will be of value to the development of better control methods. In total, 89 genotypes were found in 500 aphid samples. The diversity indices in aphid populations on pear trees fluctuated but showed a decrease with time in citrus orchards. Japanese aphid populations have greater variation in their microsatellite loci than African, European, or Southeast Asian populations. Approximately half of the genotypes were found in only one colony, whereas the remainder were identified in two or more colonies. Fifteen genotypes appeared in different years, in samples from different areas, or on different host plants. Our data suggest the existence of aphid populations with pear‐adapted genotypes and with a permanent parthenogenetic life cycle. Some of the genotypes included genes conferring resistance to pirimicarb and pyrethroid insecticides. Japanese A. gossypii populations may maintain their large genetic variation through differences in their life cycles.     

Reproductive strategies in the intercrossing corals Acropora donei and A. tenuis to prevent hybridization

Coral Reefs - Although many sympatric species of the coral Acropora spawns on the same day, hybridization is partly prevented by their species-specific fertilization manner. On the other hand,...     

Lipase-catalyzed synthesis of 6-O-vinylacetyl glucose in acetonitrile

6-O-Vinylacetyl glucose was synthesized with an immobilized lipase using vinylacetic acid and glucose in water-miscible organic solvents, of which acetonitrile gave the highest conversion of 35% at 50 mM glucose and 600 mM vinylacetic acid. The addition of 3Å molecular sieves at 60 mg ml^–1 increased the conversion to 74%. The product, 6-O-vinylacetyl glucose, was polymerized to yield a water-soluble polymer with a molecular mass of about 5000.     

Juvenile Thalassoma amblycephalum Bleeker (Labridae, Teleostei) dwelling among the tentacles of sea anemones: A cleanerfish with an unusual client?

At least 51 species of fishes are facultative symbionts of sea anemones. Most of the behavioural, ecological and physiological aspects of these associations including their costs and benefits are unknown. We recorded the behaviour and the habitat use of eight assemblages (three or ten specimens each) of the juvenile wrasse Thalassoma amblycephalum dwelling among the tentacles of the two sea anemones Entacmaea quadricolor (clonal type), and Heteractis magnifica at a coral reef in southern Japan during 16 months in daylight hours. There are only two past records of this facultative association, one from east Africa and one from Indonesia. The wrasse remained close to and was occasionally in physical contact with the host when foraging amongst the tentacles. When frightened, they took shelter among corals, away from the host anemone. The wrasse co-existed with the anemonefishes Amphiprion frenatus in E. quadricolor and A. ocellaris in H. magnifica. By using forced host contact tests ex situ and scanning electron microscopy examination of the fish epidermis, we show that juveniles of this wrasse are protected from E. quadricolor, but possibly not from H. magnifica. We suggest that juvenile T. amblycephalum dwelling among the tentacles of sea anemones are cleanerfish with an unusual client, in that they appear to clean mucus and, or, necrotic tissue from the sea anemone host.     

Proton Transfer in Liquid Water II; A Semiempirical Method to Describe Chemical Reactions

Abstract

A new semiempirical method is developed to deal with the proton transfer in liquid water. In the previous work, we have shown that two- and three-body charge transfer interactions and electrostatic interactions are the most important factors to describe the potential energy surfaces (PES) of the proton transfer in liquid water [Chemical Physics 180, 239–269, 1994], In order to take account of these factors, we develop a semiempirical method imposing the principle of electronegativity equalization to the Atoms in Molecule (AIM) method. The method is free from the well-known discrepancy of the traditional AIM methods, that is, the fractional molecular charges at large molecular separation, and thus can be applied to the charge transfer reactions. Intra- and intermolecular physical quantities, such as total energies, force vectors, dipole moment vectors and intermolecular charge transfer, obtained by the present method are found to be in good agreement with those by ab initio calculation.     

Role of RalA downstream of Rac1 in insulin-dependent glucose uptake in muscle cells

The small GTPase RalA has been implicated in glucose uptake in insulin-stimulated adipocytes, although it remains unclear whether RalA has a similar role in insulin signaling in other types of cells. Recently, we have demonstrated that the Rho family GTPase Rac1 has a critical role in insulin-dependent glucose uptake in myoblast culture and mouse skeletal muscle. However, the mechanisms underlying Rac1-dependent glucose uptake, mostly mediated by the plasma membrane translocation of the glucose transporter GLUT4, remain largely unknown. The purpose of this study is to examine the involvement of RalA in Rac1 regulation of the translocation of GLUT4 to the plasma membrane in muscle cells. Ectopic expression of a constitutively activated RalA mutant indeed stimulated GLUT4 translocation, suggesting an important role of RalA also in muscle cells. GLUT4 translocation induced by constitutively activated mutation of Rac1 or more physiologically by upstream Rac1 regulators, such as phosphoinositide 3 kinase and the guanine nucleotide exchange factor FLJ00068, was abrogated when the expression of RalA was downregulated by RNA interference. The expression of constitutively activated Rac1, on the other hand, caused GTP loading and subcellular redistribution of RalA. Collectively, we propose a novel mechanism involving RalA for Rac1-mediated GLUT4 translocation in skeletal muscle cells.     

Fused bicyclic heteroarylpiperazine-substituted l-prolylthiazolidines as highly potent DPP-4 inhibitors lacking the electrophilic nitrile group

Hypoglycemic agents with a mechanism of depeptidyl peptidase IV (DPP-4) inhibition are suitable for once daily oral dosing. It is difficult to strike a balance between inhibitory activity and duration of action in plasma for inhibitors bearing an electrophilic nitrile group. We explored fused bicyclic heteroarylpiperazine substituted at the γ-position of the proline structure in the investigation of l-prolylthiazolidines lacking the electrophilic nitrile. Among them, 2-trifluoroquinolyl compound 8g is the most potent, long-lasting DPP-4 inhibitor (IC(50)=0.37nmol/L) with high selectivity against other related peptidases. X-ray crystal structure determination of 8g indicates that CH-π interactions generated between the quinolyl ring and the guanidinyl group of Arg358 enhances the DPP-4 inhibitory activity and selectivity.