Department of Plant Biology and Pathology, Biotechnology Program, Rutgers University, New Brunswick, New Jersey, USA
Biotechnology and Genomics Concentration, Master in Business and Science Program, Rutgers University, New Brunswick, New Jersey, USA.
Appl Environ Microbiol. 2018 Oct 1;84(20). doi: 10.1128/AEM.01353-18. Print 2018 Oct 15.
C3 is a predatory strain of Gram-negative gliding bacteria that produces antifungal antibiotics by the polyketide synthetic pathway. Outer membrane vesicles (OMV) are formed as a stress response and can deliver virulence factors to host cells. The production of OMV by C3 and their role in antifungal activity are reported here. Vesicles in the range of 130 to 150 nm in diameter were discovered in the cell-free supernatants of C3 cultures. These OMV contain molecules characteristic of bacterial outer membranes, such as lipopolysaccharide and phospholipids. In addition, they contain chitinase activity and essentially all of the heat-stable antifungal activity in cell supernatants. We show here that C3 OMV can directly inhibit growth of the yeast as well as that of the filamentous fungus The activity is dependent on physical contact between OMV and the cells. Furthermore, fluorescent lipid labeling of C3 OMV demonstrated transfer of the membrane-associated probe to yeast cells, suggesting the existence of a mechanism of delivery for membrane-associated molecules. Mass spectrometric analysis of C3 OMV extracts indicates the presence of molecules with molecular weights identical to some of the previously identified antifungal products of C3. These data together suggest that OMV act as an important remote mobile component of predation by The data presented here suggest a newly discovered function of outer membrane vesicles (OMV) that are produced from the outer membrane of the bacterial species strain C3. We show that these OMV can be released from the surface of the cells to deliver antibiotics to target fungal organisms as a mechanism of killing or growth inhibition. Understanding the role of OMV in antibiotic delivery can generally lead to improved strategies for dealing with antibiotic-resistant organisms. These results also add to the evidence that some bacterially produced antibiotics can be discovered and purified using methods designed for isolation of nanoscale vesicles. Information on these systems can lead to better identification of active molecules or design of delivery vehicles for these molecules.
C3 是一种革兰氏阴性滑行细菌的掠食菌株，通过聚酮合酶途径产生抗真菌抗生素。外膜囊泡（OMV）是作为应激反应形成的，可以将毒力因子递送到宿主细胞。本文报道了 C3 产生 OMV 及其在抗真菌活性中的作用。在 C3 培养物的无细胞上清液中发现了直径在 130 至 150nm 范围内的囊泡。这些 OMV 含有细菌外膜的特征分子，如脂多糖和磷脂。此外，它们还含有几丁质酶活性和细胞上清液中几乎所有耐热的抗真菌活性。我们在这里表明，C3 OMV 可以直接抑制酵母的生长以及丝状真菌的生长。该活性取决于 OMV 与细胞之间的物理接触。此外，C3 OMV 的荧光脂质标记显示出膜相关探针向酵母细胞的转移，表明存在膜相关分子的传递机制。C3 OMV 提取物的质谱分析表明存在分子量与 C3 先前鉴定的一些抗真菌产物相同的分子。这些数据共同表明，OMV 是捕食作用的一个重要的远程移动组成部分。本文介绍了一种新发现的功能，即从细菌物种 C3 的外膜释放出的外膜囊泡（OMV）可以作为一种杀死或抑制生长的机制，将抗生素输送到目标真菌生物。了解 OMV 在抗生素输送中的作用通常可以导致针对抗抗生素生物体的改进策略。这些结果还增加了证据，表明一些细菌产生的抗生素可以使用设计用于分离纳米级囊泡的方法来发现和纯化。关于这些系统的信息可以导致更好地鉴定活性分子或设计这些分子的输送载体。
