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Chen J.-T.,Taiwan Agricultural Research Institute | Su H.-J.,Meiho University | Huang J.-W.,National Chung Hsing University
Journal of Agricultural and Food Chemistry

Secondary metabolites of Clitocybe nuda displayed antimicrobial activity against Phytophthora capsici. The culture filtrate of C. nuda was extracted with ethanol and chromatographically separated on a Sephadex LH-20 column and fractionated on a silica gel column to give eight fractions. These fractions were tested for the ability to inhibit zoospore germination of P. capsici. The most active fraction was further purified by silica gel column chromatography to yield three compounds: 2-methoxy-5-methyl-6-methoxymethyl-p-benzoquinone (1), 6-hydroxy-2H-pyran-3-carbaldehyde (2), and indole-3-carbaldehyde (3), all new to C. nuda. At a concentration of 500 mg/L, compound 3 showed complete inhibition of zoospore germination, while compounds 1 and 2 showed inhibition rates of 97 and 86%, respectively. To our knowledge, compound 1 is a newly discovered compound and, for the other two compounds, this is the first report in C. nuda. These compounds are potential candidates for new edible fungi-derived pesticides for the control of plant diseases. © 2012 American Chemical Society. Source

Yu J.-Z.,Taiwan Agricultural Research Institute | Chi H.,National Chung Hsing University | Chen B.-H.,Council of Agriculture
Biological Control

The life histories and predation rates of the ladybird beetle Harmonia dimidiata (F.) were compared among beetles kept at 15, 20, and 25°C. The beetles were fed on Aphis gossypii Glover and were maintained at 70±10% RH and a 14:10 (L:D)h photoperiod. According to the age-stage, two-sex life table, the net reproductive rates (R0) were 147.4, 98.7, and 62.5 offspring for beetles kept at 15, 20, and 25°C, respectively. Additionally, we employed both the jackknife and bootstrap techniques for estimating the means, variances, and standard errors of the population parameters. The sample means of R0 and the other population parameters obtained using the bootstrap technique fit a normal distribution, but the jackknife technique generated biologically meaningless zero values for R0. The net predation rates were 10963, 13050, and 7492 aphids for beetles kept at 15, 20, and 25°C, respectively. For a comprehensive comparison of predation potential, we incorporated both the finite rate and the predation rate into the finite predation rate. When both the growth rate and the predation rate were considered, our results showed that H. dimidiata is a more efficient biological control agent for A. gossypii at 20 and 25°C than at 15°C. © 2012 Elsevier Inc. Source

Shih C.-C.,Central Taiwan University of Science and Technology | Chen M.-H.,Taiwan Agricultural Research Institute | Lin C.-H.,Fengyuan Hospital
Evidence-based Complementary and Alternative Medicine

The study was designed to investigate the effects of extract of Clitocybe nuda (CNE) on type 1 diabetes mellitus and dyslipidemia in streptozotocin- (STZ-) induced diabetic mice. Diabetes was induced by injection of STZ. Diabetic mice were randomly divided into five groups and given orally CNE (C1: 0.2, C2: 0.5, and C3: 1.0 g/kg body weight) or metformin (Metf) or vehicle for 4 weeks. STZ induction decreased in the levels of insulin, body weight, and the weight of skeletal muscle, whereas the levels of blood glucose, hemoglobin nonenzymatically (percent HbA1c), and circulating triglyceride (P < 0.001, P < 0.001, and P < 0.01, resp.) were increased. CNE decreased the levels of blood glucose, HbA1c, and triglyceride levels, whereas it increased the levels of insulin and leptin compared with the vehicle-treated STZ group. STZ induction caused a decrease in the protein contents of skeletal muscular and hepatic phosphorylation of AMP-activated protein kinase (phospho-AMPK) and muscular glucose transporter 4 (GLUT4). Muscular phospho-AMPK contents were increased in C2-, C3-, and Metf-treated groups. CNE and Metf significantly increased the muscular proteins of GLUT4. Liver phospho-AMPK showed an increase in all CNE- and Metf-treated groups combined with the decreased hepatic glucose production by decreasing phosphenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), and 11beta hydroxysteroid dehydroxygenase (11 β -HSD1) gene, which contributed to attenuating diabetic state. The study indicated that the hypoglycemic properties of CNE were related to both the increased muscular glucose uptake and the reduction in hepatic gluconeogenesis. CNE exerts hypolipidemic effect by increasing gene expressions of peroxisome proliferator-activated receptor α (PPAR α) and decreasing expressions of fatty acid synthesis, including acyl-coenzyme A: diacylglycerol acyltransferase (DGAT) 2. Therefore, amelioration of diabetic and dyslipidemic state by CNE in STZ-induced diabetic mice occurred by regulation of GLUT4, PEPCK, DGAT2, and AMPK phosphorylation. © 2014 Chun-Ching Shih et al. Source

Species of the genus Neohelota are classified into six species groups, and 60 species are recognized. Taxonomy of the laevigata and helleri species groups is presented in detail. Two new species are described: N. viklundi sp. nov. from Myanmar and N. satoi sp. nov. from Laos. A lectotype is designated for N. tibialis Ritsema. Protibiae, genitalia, aedeagal internal sacs, eighth abdominal tergites, and fifth abdominal ventrites are illustrated for all species. © 2010 Entomological Society of America. Source

Su C.-F.,National Cheng Kung University | Wang Y.-C.,Academia Sinica, Taiwan | Hsieh T.-H.,Academia Sinica, Taiwan | Lu C.-A.,National Central University | And 2 more authors.
Plant Physiology

Rice (Oryza sativa) seedlings are particularly sensitive to chilling in early spring in temperate and subtropical zones and in high-elevation areas. Improvement of chilling tolerance in rice may significantly increase rice production. MYBS3 is a single DNA-binding repeat MYB transcription factor previously shown to mediate sugar signaling in rice. In this study, we observed that MYBS3 also plays a critical role in cold adaptation in rice. Gain- and loss-of-function analyses indicated that MYBS3 was sufficient and necessary for enhancing cold tolerance in rice. Transgenic rice constitutively overexpressing MYBS3 tolerated 4°C for at least 1 week and exhibited no yield penalty in normal field conditions. Transcription profiling of transgenic rice overexpressing or underexpressing MYBS3 led to the identification of many genes in the MYBS3-mediated cold signaling pathway. Several genes activated by MYBS3 as well as inducible by cold have previously been implicated in various abiotic stress responses and/or tolerance in rice and other plant species. Surprisingly, MYBS3 repressed the well-known DREB1/CBF-dependent cold signaling pathway in rice, and the repression appears to act at the transcriptional level. DREB1 responded quickly and transiently while MYBS3 responded slowly to cold stress, which suggests that distinct pathways act sequentially and complementarily for adapting short- and long-term cold stress in rice. Our studies thus reveal a hitherto undiscovered novel pathway that controls cold adaptation in rice. © 2010 American Society of Plant Biologists. Source

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