Department of Microbiology, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India.
Department of Microbiology, School of Sciences, P. P. Savani University, Surat, Gujarat, India.
J Basic Microbiol. 2020 Sep;60(9):799-808. doi: 10.1002/jobm.202000231. Epub 2020 Jun 29.
Samples were collected from different undisturbed areas along the coast of Gujarat like Okha, Diu, Veraval, and Somnath. A total of 68 marine isolates were obtained out of which 53 were associated with various marine macroorganisms like sponges, gastropods, and algae, whereas 15 were free living. Quorum-quenching ability of all the isolates was tested against Chromobacterium violaceum MK by co-culture technique as a way to simultaneously detect signal-degrading as well as nondegrading quorum-sensing inhibitors. Nineteen macroorganism-associated bacteria and eight free-living bacteria were found to possess quorum-sensing inhibitory activity against C. violaceum MK without affecting its growth. Isolate OA22 from grape alga and OA10 from purple sponge (Haliclona sp.) were found to possess the highest C6-HSL degradation activity and extracellular non-N-acyl-homoserine lactone degrading QSI activity, respectively. OA22 was also found to degrade 3-oxo-C12 homoserine lactone. Acid recovery of both the C6- and C12-HSL after degradation by OA22 indicated the presence of lactonase enzyme in the isolate. Cell-free supernatant of OA10 was extracted with ethyl acetate to obtain the quorum-quenching compound. Pigment inhibition in C. violaceum MK treated with OA10 extract was demonstrated in various ways and was indicative of QSI activity of the extract without degradation of the quorum-sensing signaling molecule. The isolates OA22 and OA10 were identified as Desemzia incerta and Bacillus sp., respectively, by 16S ribosomal DNA sequence analysis.
从古吉拉特邦沿海的不同未受干扰区域（如奥哈、迪奥、韦拉瓦尔和索姆纳特）采集了样本。共获得了 68 株海洋分离株，其中 53 株与各种海洋大型生物（如海绵、腹足类和藻类）有关，而 15 株为自由生活。通过共培养技术，用 Chromobacterium violaceum MK 测试所有分离株的群体感应淬灭能力，作为同时检测信号降解和非降解群体感应抑制剂的方法。发现 19 株与大型生物相关的细菌和 8 株自由生活的细菌对 C. violaceum MK 具有群体感应抑制活性，而不影响其生长。从葡萄藻中分离的 OA22 和从紫色海绵（Haliclona sp.）中分离的 OA10 对 C6-HSL 的降解活性和细胞外非-N-酰基高丝氨酸内酯降解 QSI 活性最高。OA22 还被发现降解 3-氧代-C12 高丝氨酸内酯。OA22 降解 C6-和 C12-HSL 后的酸回收表明该分离物中存在内酯酶。用乙酸乙酯提取 OA10 的无细胞上清液，以获得群体感应淬灭化合物。用 OA10 提取物处理的 C. violaceum MK 中的色素抑制在各种方式中得到证明，表明提取物具有 QSI 活性，而没有降解群体感应信号分子。通过 16S 核糖体 DNA 序列分析，将分离株 OA22 和 OA10 分别鉴定为 Desemzia incerta 和 Bacillus sp.。
