CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
Sci Rep. 2017 Oct 10;7(1):12907. doi: 10.1038/s41598-017-13424-x.
In this work, the antifungal activity of rhamnolipids produced by Pseudomonas aeruginosa #112 was evaluated against Aspergillus niger MUM 92.13 and Aspergillus carbonarius MUM 05.18. It was demonstrated that the di-rhamnolipid congeners were responsible for the antifungal activity exhibited by the crude rhamnolipid mixture, whereas mono-rhamnolipids showed a weak inhibitory activity. Furthermore, in the presence of NaCl (from 375 mM to 875 mM), the antifungal activity of the crude rhamnolipid mixture and the purified di-rhamnolipids was considerably increased. Dynamic Light Scattering studies showed that the size of the structures formed by the rhamnolipids increased as the NaCl concentration increased, being this effect more pronounced in the case of di-rhamnolipids. These results were confirmed by Confocal Scanning Laser Microscopy, which revealed the formation of giant vesicle-like structures (in the µm range) by self-assembling of the crude rhamnolipid mixture in the presence of 875 mM NaCl. In the case of the purified mono- and di-rhamnolipids, spherical structures (also in the µm range) were observed at the same conditions. The results herein obtained demonstrated a direct relationship between the rhamnolipids antifungal activity and their aggregation behaviour, opening the possibility to improve their biological activities for application in different fields.
在这项工作中，评估了铜绿假单胞菌 #112 产生的鼠李糖脂对黑曲霉 MUM 92.13 和炭黑曲霉 MUM 05.18 的抗真菌活性。结果表明，二鼠李糖脂同系物是粗鼠李糖脂混合物表现出抗真菌活性的原因，而单鼠李糖脂表现出较弱的抑制活性。此外，在 NaCl（375mM 至 875mM）存在的情况下，粗鼠李糖脂混合物和纯化的二鼠李糖脂的抗真菌活性显著增加。动态光散射研究表明，随着 NaCl 浓度的增加，鼠李糖脂形成的结构尺寸增大，二鼠李糖脂的这种效应更为明显。共聚焦扫描激光显微镜的结果证实了这一点，该结果显示在 875mM NaCl 存在下，粗鼠李糖脂混合物通过自组装形成了巨大的类似囊泡的结构（在 µm 范围内）。在相同条件下，纯化的单鼠李糖脂和二鼠李糖脂观察到了球形结构（也在 µm 范围内）。本文获得的结果表明，鼠李糖脂的抗真菌活性与其聚集行为之间存在直接关系，为在不同领域应用其提高生物活性提供了可能。
