Morphological changes of Fusarium oxysporum induced by CF66I, an antifungal compound from Burkholderia cepacia.

The morphological effects of CF66I, an antifungal compound produced by Burkholderia cepacia, on growing hyphae of Fusarium oxysporum were studied by fluorescence microscopy (FM) and transmission electron microscopy (TEM). At 20 µg/ml, CF66I strongly inhibited growth and induced significant changes of the hyphal morphology. These changes included swelling of hyphae with considerable thickening cell wall and abnormal chitin deposition, which was indicative of the alterations in cell wall structure. Furthermore, fluorescein diacetate (FDA) staining indicated the loss of intracellular esterase activity. CF66I probably inhibits fungal growth by interfering with the cell metabolic pathways. At 120 µg/ml, CF66I killed F. oxysporum (accompanied by propidium iodide permeation, intracellular cytoplasm leakage and crushing of hyphal tips), probably by direct damage to the cell membrane. Thus, there are two different antifungal mechanisms of CF66I, depending on its concentration, and further studies on this compound might be useful for us to develop a new class of antifungal agents.

Localization and dynamic change of saponin in vegetative organs of Polygala tenuifolia.

Anatomical, histochemical and phytochemical methods were used to investigate the structure, localization and dynamic changes of total saponin and senegenin of vegetative organs in Polygala tenuifolia Willd. Histochemical localization results showed that saponin accumulated mainly in parenchyma cells of vegetative organs. The phytochemical results also showed that the saponin accumulated in the vegetative organs of P. tenuifolia, with higher content in roots and lower content in the aerial parts that included stems and leaves. The saponin content and dry weight of the vegetative organs of P. tenuifolia had dynamic variance at the developmental stages and all reached the highest level in the post-fruit period. Hence, the roots and aerial parts should be gathered in August to make full use of the plant. As the root is the main medicinal organ of P. tenuifolia, the content of total saponin and senegenin of different aged and different parts of the root were determined. The content of total saponin and senegenin exhibited a sustained decreasing trend with increasing root age; therefore, the annual roots had high quality. The content of total saponin and senegenin in different parts of the root showed obvious variation. The content in the "skin areas" was much higher than that of xylem. The results offer a theoretical basis for determining the appropriate harvesting stage and a reasonable harvest of P. tenuifolia.

[Germplasm resources of Polygala tenuifolia and determination of presenegenin in processing products].

OBJECTIVE: To research the germplasm resources and the contents of senegenin in processing products of Polygala tenuifolia. METHOD: The contents of senegenin in wild Polygala tenuifolia and cultivated samples of Polygala tenuifolia were determined by RP-HPLC, and compared. RESULT: The contents of senegenin in wild reduce gradually along Shaanxi, Shanxi, Hebei to Dongbei. The contents of senegenin in cultivated three-year samples of three year Polygala tenuifolia from five main place was similar, 0.44%-0.49%. The content of senegenin were 0.44%-0.64% in the wand and 0.03%-0.09% in the residual part of stem, and the content of senegenin in Polygala tenuifolia was more than that in processing products. CONCLUSION: There is a correlation between the content of senegenin in Polygala tenuifolia and ecology environment that show a is inverse proportion with the quality grade, and the contents in the processing products were decreased. Senegenin can be used as a characteristic marker in range. This research provides a reference for search a index for quality control of Radix polygala and its processing products.