A negative transcriptional feedback loop generates circadian rhythms in Drosophila. PERIOD (PER) is a critical state-variable in this mechanism, and its abundance is tightly regulated. We found that the Drosophila homolog of Ataxin-2 (ATX2) – an RNA binding protein implicated in human neurodegenerative diseases - was required for circadian locomotor behavior. ATX2 was necessary for PER accumulation in circadian pacemaker neurons, and thus determined period length of circadian behavior. ATX2 was required for the function of TWENTY-FOUR (TYF), a crucial activator of PER translation. Indeed, ATX2 formed a complex with TYF, and promoted its interaction with Poly-A binding protein (PABP). Our work uncovers a role for ATX2 in circadian timing, and reveals that this protein functions as an activator of PER translation in circadian neurons.

Sexual behavior between males is observed in many species, but the biological factors involved are poorly known. In mammals, manipulation of dopamine has revealed the role of this neuromodulator on male sexual behavior. We used genetic and pharmacological approaches to manipulate the dopamine level in dopaminergic cells in Drosophila and investigated the consequence of this manipulation on male-male courtship behavior. Males with increased dopamine level showed enhanced propensity to court other males but did not change their courtship toward virgin females, general olfactory response, general gustatory response, or locomotor activity. Our results indicate that the high intensity of male-male interaction shown by these manipulated males was related to their altered sensory perception of other males.

No abstract

In this study, two phenol compounds, magnolol and honokiol, were extracted from Magnolia officinalis and identified by LC-MS, 1H- and 13C-NMR. The magnolol and honokiol were shown to be effective against seven pathogenic fungi, including Alternaria alternata (Fr.) Keissl, Penicillium expansum (Link) Thom, Alternaria dauci f.sp. solani, Fusarium moniliforme J. Sheld, Fusarium oxysporum Schltdl., Valsa mali Miyabe & G. Yamada, and Rhizoctonia solani J.G. Kühn, with growth inhibition of more than 57%. We also investigated the mechanisms underlying the potential antifungal activity of magnolol and honokiol. The results showed that they inhibited the growth of A. alternata in a dose-dependent manner. Moreover, magnolol and honokiol treatment resulted in distorted mycelia and increased the cell membrane permeability of A. alternata, as determined by conductivity measurements. These results suggest that magnolol and honokiol are potential antifungal agents for application against plant fungal diseases.

Diabetes is known to be associated with neurodegenerative diseases. Resveratrol, a plant-derived polyphenolic compound found in red wine, possesses antioxidant properties. In this study, we aimed to investigate the effects of resveratrol on the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt)/FoxO3a pathway in mediating high glucose (HG)-induced injuries in neuronal PC12 cells. PC12 cells were exposed to HG to establish a model of HG neurotoxicity. Results showed that pre-treating PC12 cells with resveratrol before exposure to HG led to increased cell viability, decreased apoptotic cells, and reactive oxygen species generation. Western blot analysis showed that HG decreased the phosphorylation of Akt and FoxO3a and led to the nuclear localization of FoxO3a. These effects were significantly alleviated by resveratrol co-treatment. Furthermore, the protective effects of resveratrol were abolished by PI3K/Akt inhibitor LY294002. All these results demonstrate that resveratrol protected the PC12 cells from HG-induced oxidative stress and apoptosis via the activation of PI3K/Akt/FoxO3a signaling pathway.