Sex-Inducing Activities of the Land Planarian Bipalium nobile Extract Fractions, Obtained Using Bioassay-Guided Fractionation, in the Freshwater Planarian Dugesia ryukyuensis.

Sexually mature planarians produce sex-inducing substances that induce postembryonic development of hermaphroditic reproductive organs in asexual freshwater planarians. Although the sex-inducing substances may be useful for elucidating the mechanism underlying this reproductive switch, the available information is limited. The potency of sex-inducing activity is conserved, at least at the order level. Recently, we showed that the sex-inducing activity in the land planarian Bipalium nobile was much higher than that in freshwater planarians. In the present study, we performed bioassay-guided fractionation of the sex-inducing substances produced by B. nobile and propose that crucial sex-inducing activity that triggers complete sexualization for asexual worms of the freshwater planarian Dugesia ryukyuensis is produced by additive and/or synergetic effects of various sex-inducing substances involved in ovarian development. The current study provided an isolation scheme for the minimum-required combination of sex-inducing substances for producing crucial sex-inducing activity.

Dimorphic flowers modify the visitation order of pollinators from male to female flowers.

Sexual dimorphism is a pervasive form of variation within species. Understanding how and why sexual dimorphism evolves would contribute to elucidating the mechanisms underlying the diversification of traits. In flowering plants, pollinators are considered a driver of sexual dimorphism when they affect female and male plant fitness in distinct ways. Here, we found that flowers appear to manipulate the behavior of pollinators using sexually dimorphic traits in the dioecious tree Eurya japonica. In this plant, female flowers present a higher-quality reward for pollinators, whereas male flowers have a more conspicuous appearance. Plants benefit by inducing pollinators to carry pollen from male to female flowers, and their sexual dimorphism might thus facilitate pollen movement through pollinator behavior. In two-choice experiments, pollinators frequently moved from male to female flowers, whereas computer simulation suggested that sexually dimorphic traits would evolve if pollinators changed behavior depending on the traits of the flowers they had just visited. These results suggest that the floral traits affecting the visiting order of pollinators have evolved in plants. Using E. japonica, we theoretically show that the induction of sequential behavior in pollinators might be crucial to the evolution of sexual dimorphism in flowers, and our experiments support these findings.

Isolation of microsatellite loci from the onion thrips, Thrips tabaci.

Thrips tabaci Lindeman (Thysanoptera: Thripidae), a cosmopolitan pest insect, is subdivided into at least three genetic lineages that have different biological characters, such as reproductive mode and resistibility to insecticides. Since the lineages are discriminated only by mitochondrial DNA, there is a possibility of gene flow among lineages at the genomic level. Nine polymorphic microsatellite loci were newly isolated from the taxon. Moderate to high levels of polymorphism were observed, with numbers of alleles ranging from 6 to 12 in 51 individuals. The mean observed and expected heterozygosities ranged from 0.1373 to 0.3725 and 0.5381 to 0.7748, respectively. Contrary to the expectation under Hardy-Weinberg's equilibrium, six of the nine loci exhibited a reduction to homozygosities. However, we confirmed that alleles in all the loci were inherited as Mendeilan characteristics. These new loci will be useful to explore discrimination of lineages and population genetics in this species.

Maintenance of glucose-sensitive insulin secretion of cryopreserved human islets with University of Wisconsin solution and ascorbic acid-2 glucoside.

Normal human islet cells are an ideal source for pancreas-targeted cell therapies, but the availability of human donor pancreata for islet isolation is severely limited. To effectively utilize such scarce donor organs for cell therapies, it is crucial to develop an excellent isolation, effective cryopreservation, and efficient gene transfer techniques for the transportation of isolated cells. In the present study, we investigate the effect of University of Wisconsin (UW) solution and ascorbic acid-2 glucoside (AA2G) on the cryopreservation of human islets. We also evaluate the gene transfer efficiency of a lentiviral vector expressing the E. coli LacZ gene, Lt-NLS/LacZ, in human islets. Human islets were isolated with a standard digestion method at the University of Alberta. Isolated islets were transported to Japan for 40 h and then subjected to cryopreservation experiments. The following preservation solutions were tested: UW solution with 100 micro g/mL of AA2G, UW solution, 100% fetal bovine serum (FBS), and CMRL supplemented with 10% FBS. Following three months of cryopreservation, the islets were thawed and analyzed for viability, glucose-sensitive insulin secretion, proinsulin gene expression profile, and in vivo engraftment. The islets were also subjected to monolayer formation with 804G-cell-line-derived extracellular matrix (ECM), followed by Lt-NLS/LacZ transduction. The viability, morphology, glucose-sensitive insulin secretion, proinsulin gene expression, and monolayer formation efficiency of the thawed cryopreserved islets are significantly better maintained by the use of UW solution. When AA2G (100 microg/mL) is combined with UW, such parameters are further improved. The adequate engraftment of UW + AA2G-cryopreserved human islets is achieved in the liver of nude mice. Efficient Lt-NLS/LacZ transduction is identified in monolayered islets cryopreserved with UW solution with AA2G. The present work demonstrates that the combination of UW solution with AA2G (100 microg/mL) would be a useful cryopreservation means for human islets. Human islets monolayer-cultured with 804G-derived ECM are efficiently transduced with a lentiviral vector Lt-NLS/LacZ.