The genetic basis of sexual isolation that contributes to speciation is one of the unsolved questions in evolutionary biology. Drosophila ananassae and Drosophila pallidosa are closely related, and postmating isolation has not developed between them. However, females of both species discriminate their mating partners, and this discrimination contributes to strong sexual isolation between them. By using surgical treatments, we demonstrate that male courtship songs play a dominant role in female mate discrimination. The absence of the song of D. pallidosa dramatically increased interspecies mating with D. ananassae females but reduced intraspecies mating with D. pallidosa females. Furthermore, genetic analysis and chromosomal introgression by repeated backcrosses to D. pallidosa males identified possible loci that control female discrimination in each species. These loci were mapped on distinct positions near the Delta locus on the middle of the left arm of the second chromosome. Because the mate discrimination we studied is well developed and is the only known mechanism that prevents gene flow between them, these loci may have played crucial roles in the evolution of reproductive isolation, and therefore, in the speciation process between these two species.

US is reliable for the detection of injuries and the identification of solid-organ injuries despite its poor sensitivity for intestinal injuries.

Retrograde signaling from postsynaptic cells to presynaptic neurons is essential for regulation of synaptic development, maintenance, and plasticity. Here we report that the novel protein AEX-1 controls retrograde signaling at neuromuscular junctions in C. elegans. aex-1 mutants show neural defects including reduced presynaptic activity and abnormal localization of the synaptic vesicle fusion protein UNC-13. Muscle-specific AEX-1 expression rescues these defects but neuron-specific expression does not. AEX-1 has an UNC-13 homologous domain and appears to regulate exocytosis in muscles. This retrograde signaling requires prohormone-convertase function in muscles, suggesting that a peptide is the retrograde signal. This signal regulates synaptic vesicle release via the EGL-30 Gq(alpha) protein at presynaptic terminals.

Drosophila ananassae and its relatives have many advantages as a model of genetic differentiation and speciation. In this report, we examine evolutionary relationships in the ananassae species subgroup using a multi-locus molecular data set, karyotypes, meiotic chromosome configuration, chromosomal inversions, morphological traits, and patterns of reproductive isolation. We describe several new taxa that are the closest known relatives of D. ananassae. Analysis of Y-chromosomal and mitochondrial haplotypes, shared chromosome arrangements, pre-mating isolation and hybrid male sterility suggests that these taxa represent a recent evolutionary radiation and may experience substantial gene flow. We discuss possible evolutionary histories of these species and give a formal description of one of them as D. parapallidosa Tobari sp. n. The comparative framework established by this study, combined with the recent sequencing of the D. ananassae genome, will facilitate future studies of reproductive isolation, phenotypic variation and genome evolution in this lineage.

Propolis, a resinous substance collected by honeybees by mixing their saliva with plant sources, including tree bark and leaves and then mixed with secreted beeswax, possesses a variety of bioactivities. Whereas caffeic acid phenethyl ester (CAPE) has been recognized as a major bioactive ingredient in New Zealand propolis, Brazilian green propolis, on the other hand, possesses artepillin C (ARC). In this study, we report that, similar to CAPE, ARC docks into and abrogates mortalin-p53 complexes, causing the activation of p53 and the growth arrest of cancer cells. Cell viability assays using ARC and green propolis-supercritical extract (GPSE) revealed higher cytotoxicity in the latter, supported by nuclear translocation and the activation of p53. Furthermore, in vivo tumor suppression assays using nude mice, we found that GPSE and its conjugate with γ cyclodextrin (γCD) possessed more potent anticancer activity than purified ARC. GPSE‑γCD may thus be recommended as a natural, effective and economic anticancer amalgam.

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Na + /K + ATPase is a plasma membrane-localized sodium pump that maintains the ion gradients between the extracellular and intracellular environments, which in turn controls the cellular resting membrane potential. Recent evidence suggests that the pump is also localized at synapses and regulates synaptic efficacy. However, its precise function at the synapse is unknown. Here we show that two mutations in the α subunit of the eat-6 Na + /K + ATPase in Caenorhabditis elegans dramatically increase the sensitivity to acetylcholine (Ach) agonists and alter the localization of nicotinic Ach receptors at the neuromuscular junction (NMJ). These defects can be rescued by mutated EAT-6 proteins which lack its pump activity, suggesting the presence of a novel function for Ach signaling. The Na + /K + ATPase accumulates at postsynaptic sites and appears to surround Ach receptors to maintain rigid clusters at the NMJ. Our findings suggest a critical pump activityindependent, allele -specific role for Na + /K + ATPase on postsynaptic organization and synaptic efficacy.

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