雪地茶内生真菌<i>Apiospora malaysiana</i>体外抑菌活性及稳定性研究

贺秋桦; 刘梦龙; 郭启新; 丁海燕

doi:10.13386/j.issn1002-0306.2023010047

雪地茶内生真菌Apiospora malaysiana体外抑菌活性及稳定性研究

Study on Antimicrobial Activity and Stability of Endophytic Fungus Apiospora malaysiana from Thamnolia subuliformis in Vitro

摘要

摘要: 为探究雪地茶内生真菌Apiospora malaysiana抗菌药物开发潜力，本研究在对比6种常用体外抑菌活性测定方法效果后，进一步确定Apiospora malaysiana对常见致病微生物的抗菌谱。以敏感性最强的金黄色葡萄球菌为指示菌，探究保存时间、温度、紫外照射时长、pH等因素对Apiospora malaysiana体外抑菌活性稳定性的影响。结果表明，使用三种抑制细菌检测方法（平板打孔法、滤纸片法和牛津杯法）对Apiospora malaysiana体外抑菌活性检测结果并的影响无显著性差异（P>0.05），但三种抑制真菌方法的结果显示，菌丝生长速率法最优（抑制率100%），平板对峙法的效果远低于前者（抑制率只有24.0%），而滤纸圆片扩散法则无抑制效果。体外抑菌试验结果表明Apiospora malaysiana对多种革兰氏阳性菌和致病真菌有较强的抑制作用，其中金黄色葡萄球菌对其敏感性最强（抑菌圈直径18.3 mm，高度敏感），此外，Apiospora malaysiana对致病真菌如耐药型白色念珠菌（高度敏感）、灰葡萄孢、立枯丝核菌（抑制率100%）也具有较强的抑菌活性。抑菌稳定性试验结果表明，不同保存时间、温度、紫外照射时间对Apiospora malaysiana的体外抑菌活性均无显著影响（P>0.05），但pH对其抑菌活性影响较大（P<0.05），当pH低于其提取物本底pH（5.5）时，抑菌圈直径降低，当pH调整至高于其提取物本底pH时，Apiospora malaysiana体外抑菌活性消失。本试验结果表明雪地茶内生真菌Apiospora malaysiana具有广泛、良好的抑菌活性，且在常规条件下其体外抑菌稳定性较强，有进一步开发为抗生素及食品保鲜剂的潜力。

Abstract: In order to explore the antibiotics development potential of the endophytic fungus Apiospora malaysiana from Thamnolia subuliformis, the antimicrobial spectrum of Apiospora malaysiana against common pathogen was determined after comparing the effects of six commonly used methods for determination of in vitro antimicrobial activity. The effects of storage time, temperature, ultraviolet irradiation time, and pH on the stability of antimicrobial activities of Apiospora malaysiana in vitro were further investigated by using the most sensitive Staphylococcus aureus as the indicator bacterium. The results showed that there was no significant difference in the antimicrobial activity of Apiospora malaysiana in vitro by three methods (plate punching method, filter paper method, and Oxford cup method) (P>0.05). However, the results of the three fungal inhabition methods showed that the mycelial growth rate method was optimal (inhibition rate of 100%), the effect of the plate confrontation method was much lower than the former (inhibition rate of only 24.0%), and the filter paper diffusion method had no inhibiting effect. The results of in vitro antimicrobial test showed that Apiospora malaysiana had strong inhibiting effects on a variety of Gram-positive bacteria and pathogenic fungi, among which Staphylococcus aureus was the most sensitive (the diameter of the inhibition zone was 18.3 mm, highly sensitive). In addition, Apiospora malaysiana also had strong antimicrobial activity against pathogenic fungi such as drug-resistant Candida albicans (highly sensitive), Botrytis cinerea, and Rhizoctonia solani (inhibition rate of 100%). The results of the antimicrobial stability test showed that different storage time, temperature, and ultraviolet irradiation time had no significant effects on the in vitro antimicrobial activity of Apiospora malaysiana (P>0.05), but pH had a great effect on its in vitro antimicrobial activity (P<0.05). When pH was lower than the background pH (5.5) of the extract, the diameter of the inhibition zone decreased. When pH was adjusted to higher than the background pH of the extract, the in vitro antimicrobial activity of Apiospora malaysiana disappeared. The results showed that the endophytic fungus Apiospora malaysiana from Thamnolia subuliformis had broad and great antimicrobial activity, and its antimicrobial stability in vitro was strong under normal conditions, which had the potential to be further developed into antibiotics and food preservatives.