pH值对巴西橡胶树胶乳β-1,3-葡聚糖酶结合黄色体膜的影响

基于黄色体内含物中的多种可溶性蛋白质以及黄色体膜在胶乳凝固中所起到的重要作用,已提出了多种阐明胶乳凝固机制的假说,但有关β-1,3-葡聚糖酶在胶乳凝固中的作用尚无报导。通过聚丙烯酰胺凝胶电泳(Tricine-SDS-PAGE)和免疫印迹技术(Western blotting),对不同pH值条件下破裂收集的黄色体内含物和膜组分中的蛋白质进行研究。结果表明,在pH5.5左右的酸性环境中,β-1,3-葡聚糖酶主要表现为可溶性蛋白质,很少结合黄色体膜;但在pH6.9左右的中性及偏碱性的环境下,大量β-1,3-葡聚糖酶结合到黄色体膜上,可溶性蛋白所占的比例很低。首次发现了β-1,3-葡聚糖酶可以结合黄色体膜,二者结合的程度明显受环境pH值的影响。该结果对于认识β-1,3-葡聚糖酶的生物功能,完善黄色体在胶乳凝固中的作用及阐明乳管堵塞机制具有重要意义。

Synergistic antibacterial effect of honey and Herba Ocimi Basilici against some bacterial pathogens

OBJECTIVE： To evaluate the antibacterial activity of the combination of different honey brands and methanolic fraction of Herba Ocimi Basilici using agar well diffusion assay. METHODS： The antibacterial activity was deter- mined against thirteen pathogenic bacterial clini- cal isolates including six gram negative （Klebsiella pneumonia, Pseudomonas aeroginosa, Escherichia coli, Salmonella typhi, Salmonella typhimirium, Xanthomonas campestris） and six gram positive strains （Enterococcus faecalis faecalis, Bacillus subti- lis, Staphylococcus aureus, Clostridium perfringens type C, Clostridium perfringens type D, CIostridium chauvoei）. Agar well diffusion method was used while zones of inhibition were measured with verni- er scale. RESULTS： At higher concentration, all the honey brands showed good to significant activity. Thehighest activity was observed for Hamdard brand honey （27.60±0.40） against Enterococcus faecalis. CONCLUSION： These results revealed that combi- nations of plant extracts of Herba Ocimi Basilici with honey can be used for the development of potent and novel antibacterial agents.