Analysis of shading on DNA methylation by MSAP in Pinellia ternata / 中国中药杂志

Pinellia ternata is a medicinal herb of Araceae, and its tubers are used as medicines. It is a common Chinese herbal medicine in China and has a large market demand. When exposing to strong light intensity and high temperature during the growth process, P. ternata withers in a phenomenon known as "sprout tumble", which largely limits tuber production. Shade can effectively delay sprout tumble formation and increase its yield, however the relevant regulation mechanism is unclear. DNA methylation, as a self-modifying response to environmental changes, is often involved in the regulation of plant growth and development. In this study, P. ternata grown under natural light and 90% shading were selected as the control group and the experimental group for genomic DNA methylation analysis by using methylate sensitive amplification polymorphism(MSAP). The results showed that a total of 617 loci were detected with 20 pairs of primers, of which 311 were in the natural light group and 306 in the shading group. The methylation sites in the light and shading groups accounted for 58.2% and 71.57%, respectively, and the methylation ratios in the methylation sites were 27.65% and 29.41%, respectively, indicating that shading significantly induced the genome DNA methylation of P. ternata. Compared to the natural light group, shading promoted 32.51% of the genes methylation, while inducing 16.25% gene demethylation. This study reveals the DNA methylation variation of P. ternata under shading conditions, which lays a preliminary theoretical foundation for further analysis of the mechanism of shading regulation of P. ternata growth from epigenetic level.

Fungal growth and mycotoxigenic production in certain medicinal herbs subjected to prolonged cold storage and possible control by gamma irradiation

Twenty-four samples representing four kinds of medicinal herbs; namely, caraway, khella, shih balady and wild chamomile, were exposed to increasing doses of gamma radiation [from 0 to 0.5 kGy]. The sublethal doses ranged from 0.5 to 3.0 kGy. Five fungal isolates from the irradiated herb samples could produced aflatoxins and one isolate could produce ochratoxin B. The isolated fungi were identified as Aspergillus species. The herb samples were stored for two years at 5 +/- 1C and then exposed to increasing dose levels of gamma radiation. One fungal isolate from the stored khella identified as Aspergillus flavus and was confirmed for aflatoxins B1 and B2 production. The D10-value of the tested Asp. flavus isolate was 0.5 kGy

Effect of storage on total moulds counts in certain locally marketed medicinal herbs and possible decontamination by gamma irradiation

Twenty-four samples representing Carum carvi fruits, Ammi visnaga fruits, Artemisia judica and Matricaria chamomilla were exposed to increasing doses of gamma-irradiation. No significant difference could be detected in the mould count of Carum carvi and Ammi visnaga samples before and after storage for a period of two years, while a significant decrease in the total mould count of Artemisia judica and Matricaria chamomilla samples was observed after storage. The effect of gamma-irradiation on the total mould count in the four medicinal herbs was evaluated before and after storage for two years. A gamma radiation dose of 3.0 kGy could decontaminate Carum carvi fruits and Matricaria chamomilla samples from fungi whereas, a higher dose level at 4.0 kGy was required to decontaminate Ammi visnaga fruits and Artemisia judica samples, on the other hand, a dose level up to 3.0 kGy was enough to decontaminate the samples stored for two years