Effect of extensin-like OsPEX1 on pollen fertility in rice.

LRXs (leucine-rich repeat extensins) are chimeric cell wall proteins containing an N-terminal leucine-rich repeat (LRR) and a C-terminal extensin domain. Increasing evidences suggest that LRXs family genes play important roles in pollen germination and pollen tube growth in Arabidopsis thaliana. However, the functions of rice (Oryza sativa L.) LRX genes in pollen development remain poorly understood. Bioinformatics analysis showed that the rice LRX gene family consist of eight members, namely OsPEX3, OsLRX3 and OsLRX5 located on chromosome 1, OsLRX1, OsLRX3, OsLRX2,OsPEX1 and OsPEX2 located on chromosome 2, 5, 6, 11 and 12, respectively. The OsPEX1 gene is preferentially expressed in rice anther, suggesting that it may be involved in the regulation of pollen development. Next, we further investigated the role of the OsPEX1 gene in rice by knockdown of its expression using an RNAi approach. The OsPEX1 RNAi transgenic lines showed a significant decrease in seed setting rate (10%~30%) due to pollen sterility. Further quantitative RT-PCR analysis indicated that the OsPEX1 gene was significantly down-regulated in the RNAi transgenic lines. The results indicate that the OsPEX1plays an important role in the regulation of rice pollen development. Further studies on this gene could provide insights on the molecular and genetic mechanisms in this developmental process.

Toxicological Assessment of Trans-resveratrol / 中草药·英文版

Objective To evaluate toxicity and safety of trans-resveratrol (t-RSV). Methods For assays of acute toxicity,genetic toxicity, and sub-chronic toxicity, Ames test, mice bone marrow erythrocyte micronucleus, and mice sperm abnormality were performed. Results In the acute oral toxicity tests, maximum tolerable dose (15 g/kg) in male and female Kunming mice showed no toxicological signs. For 90-d feeding of t-RSV at dosage range of 167-500 mg/(kg·d) in both male and female Sprague-Dawley rats, no noticeable toxicological effects were observed.Conclusion T-RSV has no acute toxicity and no genotoxicity, no harmful effects on the human body at the tested dosage range and thus resveratrol is safe for human consumption.