Design and synthesis of novel benzofurans as a new class of antifungal agents targeting fungal N-myristoyltransferase. Part 2

Modification of the C-2 position of a benzofuran derivative 6 (RO-09-4609), an N-myristoyltransferase (Nmt) inhibitor, has led us to discover antifungal agents that are active in a murine systemic candidiasis model. The drug design is based on the analysis of a crystal structure of a Candida Nmt complex with 2. The optimization has been guided by various biological evaluations including a quasi in vivo assay and pharmacokinetic analysis.     

Variation and evolution of the complex life cycle in Adelgidae (Hemiptera)

The family Adelgidae is a small group of insects within Aphidoidea (Hemiptera). Adelgids are typically holocyclic with host‐alternation between the primary and secondary hosts, but some anholocyclic species persist either on the primary or secondary host. Like Aphididae, complexities and variation of adelgid life cycles are good models for understanding the evolution of complex life cycles. In this review, we outline the complex life cycles of adelgids, and current status and recent advances in adelgid life cycle studies. We also discuss the evolution of adelgid life cycles by comparing them to closely related aphid life cycles. A switch from holocycly to anholocycly on the primary host needs evolutionary innovations in gallicola behavior and reproduction. This radical evolution can be explained by mutations in a regulatory system that controls the sequence of gene sets producing phenotypes of one morph. In contrast, anholocycly on the secondary host consists of a series of exulis generations already existing in the holocycle. Thus, it may evolve by loss of primary‐host generations through extinction of the primary host, expansion beyond the geographical range of the primary host, or loss of male‐producing sexuparae that return to the primary host. Although the holocycle and its anholocyclic derivatives have been regarded as different species, morphological, ecological and genetic differences are too subtle to separate them into different species. The holocycle and its anholocyclic derivatives should not be split into different species without clearly identifiable morphological differences.     

Inhibition of the RhoA/Rho kinase system attenuates catecholamine biosynthesis in PC 12 rat pheochromocytoma cells

The small GTPase, RhoA, and its downstream effecter Rho-kinase (ROK) are reported to be involved in various cellular functions, such as myosin light chain phosphorylation during smooth muscle contraction and exocytosis. Indeed, growing evidence suggests that the RhoA/Rho-kinase pathway plays an important role in regulating exocytosis in these cells. However, it is not known whether the RhoA/Rho-kinase pathway has an effect on catecholamine synthesis. Using the rat pheochromocytoma cell line, PC12, we examined the effects of either Rho-kinase inhibitor (Y27632) or RhoA inhibitor (C3 toxin) on nicotine-induced catecholamine biosynthesis. We show that nicotine (10 microM) induces a significant, though transient, increase in RhoA activation in these cells. Treatment with either Y27632 (1 microM) or C3 toxin (10 microg/ml) significantly inhibited the nicotine-induced increase of tyrosine hydroxylase (TH) mRNA and the corresponding enzyme activity. TH catalyzes the rate-limiting step in the biosynthesis of catecholamine. Y27632 significantly inhibited nicotine-induced phosphorylation of TH at Ser40 as well as Ser19, which are known to be phosphorylated by Ca(2+)/calmodulin kinase II. Furthermore, Y27632 (10 microM) as well as C3 toxin (10 microg/ml) significantly inhibited the nicotine-induced increase of TH at the protein level. Thus, we propose that activation of RhoA, and its downstream effecter Rho-kinase, is a prerequisite for catecholamine biosynthesis in PC12 cells. At the concentrations used in our experiments, Y27632 does not affect cAMP/PKA activity or PKC activity, indicating that the inhibitory effect of Y27632 can be attributed to the inhibition of Rho-kinase activity as observed in chromaffin cells. In contrast, neither Y27632 (10 microM) nor C3 toxin (10 microg/ml) significantly altered catecholamine secretion in PC12 cells. In conclusion, we have demonstrated that inhibition of the Rho/Rho-kinase pathway in chromaffin cells lowers TH activity, probably through CaMKII inhibition. By contrast, neither Y27632 nor C3 toxin affect the secretion of catecholamine.