Effect of photoperiod on winter and summer diapause of the soybean pod borer Leguminivora glycinivorella (Lepidoptera: Tortricidae)

To understand the geographical differences between diapause systems and synchronization of adult occurrence in the soybean pod borer Leguminivora glycinivorella (Lepidoptera: Tortricidae), we examined the timing of winter diapause termination and intensity of summer diapause using univoltine and potentially bivoltine individuals in Iwate, Japan. In laboratory rearing experiments of mature larvae maintained at constant temperature (20 °C), winter diapause intensity weakened by January without photoperiodic responses. Meanwhile, summer diapause was maintained by the long day length and presumably terminated with the photoperiodic transition from long to short day length. The intensity of summer diapause was stronger for cocoons that transitioned from a 16 h light to 8 h dark (LD 16:8) to a LD 15:9 photoperiod than for those that transitioned from LD 15:9 to LD 14:10. These results suggest that populations distributed in relatively low-latitude areas, with partly or potentially bivoltine individuals, would have a weaker summer diapause or none at all. Moreover, sexual differences in the number of days to emergence were not detected when individuals experienced a photoperiodic transition from long to short day length, suggesting that the summer diapause system may function to synchronize the emergence of males and females in the population examined.     

Autophagy Benefits the Replication of Newcastle Disease Virus in Chicken Cells and Tissues

Newcastle disease virus (NDV) is an important avian pathogen. We previously reported that NDV triggers autophagy in U251 glioma cells, resulting in enhanced virus replication. In this study, we investigated whether NDV triggers autophagy in chicken cells and tissues to enhance virus replication. We demonstrated that NDV infection induced steady-state autophagy in chicken-derived DF-1 cells and in primary chicken embryo fibroblast (CEF) cells, evident through increased double- or single-membrane vesicles, the accumulation of green fluorescent protein (GFP)-LC3 dots, and the conversion of LC3-I to LC3-II. In addition, we measured autophagic flux by monitoring p62/SQSTM1 degradation, LC3-II turnover, and GFP-LC3 lysosomal delivery and proteolysis, to confirm that NDV infection induced the complete autophagic process. Inhibition of autophagy by pharmacological inhibitors and RNA interference reduced virus replication, indicating an important role for autophagy in NDV infection. Furthermore, we conducted in vivo experiments and observed the conversion of LC3-I to LC3-II in heart, liver, spleen, lung, and kidney of NDV-infected chickens. Regulation of the induction of autophagy with wortmannin, chloroquine, or starvation treatment affects NDV production and pathogenesis in tissues of both lung and intestine; however, treatment with rapamycin, an autophagy inducer of mammalian cells, showed no detectable changes in chicken cells and tissues. Moreover, administration of the autophagy inhibitor wortmannin increased the survival rate of NDV-infected chickens. Our studies provide strong evidence that NDV infection induces autophagy which benefits NDV replication in chicken cells and tissues.     

Extractive cultivation of Lactococcus lactis using a polyethylene glycol/MgSO4 · 7H2O aqueous two-phase system to produce nisin

To relieve lactic acid inhibition, an aqueous two-phase system (ATPS) was used to grow Lactococcus lactis. Its composition was 11% (w/v) PEG 20000/3.5% (w/v) MgSO₄ 7H₂O. In this ATPS medium, the cells were completely partitioned in the bottom phase, and lactic acid had the biggest partition coefficient of the eight ATPS media tested. The cell biomass in this medium was 0.64 mg ml^–1, only 60% of that of the control medium, but nisin production (803 IU ml^–1) was enhanced by 33%. The increase in nisin was explained as a result of extraction of lactic acid from the bottom phase to the top one. The changes of tie-line length and phase volume ratio for the identical tie line could affect cell growth and nisin accumulation.     

Action of Brefeldin A on Amphibian Neurons: Passage of Newly Synthesized Proteins Through the Golgi Complex Is Not Required for Continued Fast Organelle Transport in Axons

Abstract: The relation between the availability of newly synthesized protein and lipid and the axonal transport of optically detectable organelles was examined in peripheral nerve preparations of amphibia (Rana catesbeiana and Xenopus laevis) in which intracellular traffic from the endo-plasmic reticulum to the Golgi complex was inhibited with brefeldin A (BFA). Accumulation of fast-transported radio-labeled protein or phospholipid proximal to a sciatic nerve ligature was monitored in vitro in preparations of dorsal root ganglia and sciatic nerve. Organelle transport was examined by computer-enhanced video microscopy of single myelinated axons. BFA reduced the amount of radiolabeled protein and lipid entering the fast-transport system of the axon without affecting either the synthesis or the transport rate of these molecules. The time course of the effect of BFA on axonal transport is consistent with an action at an early step in the intrasomal pathway, and with its action being related to the observed rapid (<1 h) disassembly of the Golgi complex. At a concentration of BFA that reduced fast-transported protein by >95%, no effect was observed on the flux or velocity of anterograde or retrograde organelle transport in axons for at least 20 h. Bidirectional axonal transport of organelles was similarly unaffected following suppression of protein synthesis by >99%. The findings suggest that the anterograde flux of transport organelles is not critically dependent on a supply of newly synthesized membrane precursors. The possibilities are considered that anterograde organelles normally arise from membrane components supplied from a post-Golgi storage pool, as well as from recycled retrograde organelles.     

Differential effects of secreted frizzled-related proteins (sFRPs) on osteoblastic differentiation of mouse mesenchymal cells and apoptosis of osteoblasts

Secreted frizzled-related proteins (sFRPs) are modulators of Wnt signaling. This study was undertaken for definitive assessment of contribution of different sFRPs in osteoblastic differentiation of mesenchymal progenitor cells and apoptosis of osteoblasts. Treatment of C3H10T1/2 cells with sFRP-2 at concentrations of 10, 50, and 100 nM and sFRP-4 at low concentrations (5 nM) significantly increased Wnt-3A-induced alkaline phosphatase (ALP) activities, whereas sFRP-1 or 3 did not. Retroviral transduction of the sFRP-2 but not other sFRPs also significantly enhanced ALP activity induced by β-glycerophosphate and ascorbic acid. Furthermore, transfection of all the sFRP expression vectors significantly increased β-catenin/TCF reporter activity and the effects were most prominent with sFRP-2 and -4. In osteoblast apoptosis assay, only sFRP-3 increased etoposide-induced apoptosis in MC3T3-E1 mouse osteoblasts. In conclusion, we found that different repertoires of sFRPs exert differential effects on osteoblastic differentiation of mouse mesenchymal cells and cellular apoptosis of mouse osteoblasts in vitro.     

In vitro cultivation of spermatocysts to matured sperm in the silkworm Bombyx mori

Bombyx spermatogonia are bipotential, producing nucleate eupyrene sperm and anucleate apyrene sperm. An in vitro cultivation of spermatocysts of Bombyx mori from spermatocytes to matured sperm was established. The present experiment made clear that: (i) spermatocysts must be isolated; (ii) constant shaking at 45 r.p.m. was necessary; and (iii) the addition of Bombyx hemolymph (BH) was indispensable for successful cultivation. In the absence of BH, spermatogenesis proceeded normally for 2 or 3 days and, thereafter, spermatocytes and sperm bundles began to degenerate. The best results for normal eupyrene spermatogenesis were obtained when culture medium containing BH of the corresponding stage was used in every exchange of the medium at 72 h intervals. None or only a small number of apyrene sperm bundles was produced by this culture system when spermatocysts from larval testes were used, although eupyrene spermatogenesis proceeded normally to form matured, or squeezed, sperm bundles.     

Stilbenoids from the stem of Gnetum latifolium (Gnetaceae)

An acetone extract of the stem of Gnetum latifolium Blume afforded the stilbene trimer (latifolol) together with five known stilbenoids (gnetin E, gnetin D, gnetin C, (-)epsilon -viniferin and resveratrol). Their structures were elucidated on the basis of spectral evidence, in particular by using 2D NMR methods.     

Bilateral otolith contribution to spatial coding in the vestibular system

Recent work on the coding of spatial information in central otolith neurons has significantly advanced our knowledge of signal transformation from head-fixed otolith coordinates to space-centered coordinates during motion. In this review, emphasis is placed on the neural mechanisms by which signals generated at the bilateral labyrinths are recognized as gravity-dependent spatial information and in turn as substrate for otolithic reflexes. We first focus on the spatiotemporal neuronal response patterns (i.e. one- and two-dimensional neurons) to pure otolith stimulation, as assessed by single unit recording from the vestibular nucleus in labyrinth-intact animals. These spatiotemporal features are also analyzed in association with other electrophysiological properties to evaluate their role in the central construction of a spatial frame of reference in the otolith system. Data derived from animals with elimination of inputs from one labyrinth then provide evidence that during vestibular stimulation signals arising from a single utricle are operative at the level of both the ipsilateral and contralateral vestibular nuclei. Hemilabyrinthectomy also revealed neural asymmetries in spontaneous activity, response dynamics and spatial coding behavior between neuronal subpopulations on the two sides and as a result suggested a segregation of otolith signals reaching the ipsilateral and contralateral vestibular nuclei. Recent studies have confirmed and extended previous observations that the recovery of resting activity within the vestibular nuclear complex during vestibular compensation is related to changes in both intrinsic membrane properties and capacities to respond to extracellular factors. The bilateral imbalance provides the basis for deranged spatial coding and motor deficits accompanying hemilabyrinthectomy. Taken together, these experimental findings indicate that in the normal state converging inputs from bilateral vestibular labyrinths are essential to spatiotemporal signal transformation at the central otolith neurons during low-frequency head movements.     

Overexpression of SOD1 protects vulnerable motor neurons after spinal cord injury by attenuating mitochondrial cytochrome c release

Defective Cu,Zn-superoxide dismutase (SOD1) is responsible for some types of amyotrophic lateral sclerosis, and ventral horn motor neurons (VMN) have been shown to die through a mitochondria-dependent apoptotic pathway after chronic exposure to high levels of reactive oxygen species (ROS). VMN are also selectively vulnerable to mild spinal cord injury (SCI); however, the involvement of SOD1, ROS, and apoptosis in their death has not been clarified. Mild compression SCI was induced in SOD1-overexpressing transgenic rats and wild-type littermates. Superoxide production, mitochondrial release of cytochrome c, and activation of caspase-9 were examined, and apoptotic DNA injury was also characterized. In the wild-type animals, increased superoxide production, mitochondrial release of cytochrome c, and cleaved caspase-9 were observed exclusively in VMN after SCI. Subsequently, a majority of VMN (75%) selectively underwent delayed apoptotic cell death. Transgenic animals showed less superoxide production, mitochondrial cytochrome c release, and caspase-9 activation, resulting in death of only 45% of the VMN. These results suggest that the ROS-initiated mitochondrial signaling pathway possibly plays a pivotal role in apoptotic VMN death after SCI and that increased levels of SOD1 in VMN reduce oxidative stress, thereby attenuating the activation of the pathway and delayed cell death.