[Effects of nitrogen level on growth of Tetrastigma hemsleyanum and phytochemical content and antioxidant activity in stems and leaves].

As a rare endangered medical plant that newly cultivated,little experimental information is available for growth and metabolites of Tetrastigma hemsleyanum in response to nitrogen( N). The effects of different levels of N on growth of T. hemsleyanum and the content of phytochemicals( polysaccharide,total flavonoids and phenolics) and antioxidant activity( ABTS and FRAP) in stems and leaves were investigated in this study. A certain amount of N had positive effects on most of biological traits,and excessive dose of N went against growth of T. hemsleyanum. With N levels decreased,the polysaccharide content in stems and leaves had no significant change,while the total flavonoid and phenolic content,and antioxidant activities increased steadily. Antioxidant activities and total flavonoid and phenolic content had significant positive correlation. Excessive N fertilizer should be avoided by cultivation.

Optimization of fermentation process for the production of intracellular polysaccharide from Paecilomyces cicadae and the immuno-stimulating activity of intracellular polysaccharide.

Optimization of fermentation process for the production of intracellular polysaccharide (IPS) from the fungus Paecilomyces cicadae and the immuno-stimulating activity of IPS were carried out. The quantitative effects of initial pH, fermentation temperature and time on the yield of IPS content produced by P. cicadae in submerged fermentation were investigated separately using response surface methodology (RSM). The three factors chosen for the present investigation were based on the results of a previous Plackett-Burman (PB) design. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods. RSM analysis showed good correspondence between experimental and predicted values. It was found that three parameters represented significant effect. Probability value (p < 0.0001) demonstrated a very high significance for the regression model. By solving the regression equation and analyzing the response surface contour plots, the optimal process parameters were determined, i.e. fermentation temperature 24.53 °C, initial pH 7.46 and fermentation time 73.9 h. The maximum predicted yield of IPS was 356.02 µg/ml under the optimal conditions. Meanwhile, IPS from P. cicadae was found to have direct immuno-stimulating activity in vitro on murine macrophage RAW264.7 proliferative response and to stimulate nitric oxide generation in a dose-dependent manner.

New available SCAR markers: potentially useful in distinguishing a commercial strain of the superior type from other strains of Lentinula edodes in China.

At present, more than 100 strains of Lentinula edodes are cultivated on a commercial scale in China. A simple, reliable, and effective method to distinguish some commercial strains of the superior type from other commercial strains is very important for the Lentinula industry. In this study, 23 commercial strains of L. edodes cultivated widely in China at present were collected and analyzed with randomly amplified polymorphic DNA (RAPD) technique. Three informative dominant sequence characterized amplified region (SCAR) markers were developed by designing three pairs of specific SCAR primers from three sequenced differential RAPD bands, respectively. Based on the three SCAR markers, three different multiplex polymerase chain reaction (PCR) phenotypes were detected among the 23 studied commercial strains and in which a multilocus phenotype characterizing a commercial strain Cr02 of the superior type could potentially be used to distinguish this strain from the other 22 studied commercial strains. To our knowledge, this study is the first to describe the development of a multiplex PCR technique based on SCAR markers for detecting the molecular phenotypes among commercial strains of L. edodes in China.