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.

中文翻译：

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与海洋大型生物相关的细菌是群体感应拮抗剂的潜在来源

样本是从古吉拉特邦海岸的不同未受干扰地区收集的，如 Okha、Diu、Veraval 和 Somnath。共获得了 68 种海洋分离物，其中 53 种与海绵、腹足类和藻类等各种海洋大型生物有关，而 15 种是自由生活的。通过共培养技术测试了所有分离株对紫色色杆菌 MK 的群体淬灭能力，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 种大型生物相关细菌和 8 种自由生活细菌对 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 OA22，从紫色海绵 (Haliclona sp.) 中分离 OA10。) 分别具有最高的 C6-HSL 降解活性和细胞外非 N-酰基高丝氨酸内酯降解 QSI 活性。还发现 OA22 可降解 3-oxo-C12 高丝氨酸内酯。C6- 和 C12-HSL 在被 OA22 降解后的酸回收表明分离物中存在内酯酶。OA10 的无细胞上清液用乙酸乙酯萃取，得到群体淬灭化合物。以多种方式证明了用 OA10 提取物处理的 C. violaceum MK 中的色素抑制作用，表明提取物的 QSI 活性，而群体感应信号分子没有降解。通过16S核糖体DNA序列分析，分离株OA22和OA10分别被鉴定为Desemzia incerta和Bacillus sp.。还发现 OA22 可降解 3-oxo-C12 高丝氨酸内酯。C6- 和 C12-HSL 在被 OA22 降解后的酸回收表明分离物中存在内酯酶。OA10 的无细胞上清液用乙酸乙酯萃取，得到群体淬灭化合物。以多种方式证明了用 OA10 提取物处理的 C. violaceum MK 中的色素抑制作用，表明提取物的 QSI 活性，而群体感应信号分子没有降解。通过16S核糖体DNA序列分析，分离株OA22和OA10分别被鉴定为Desemzia incerta和Bacillus sp.。还发现 OA22 可降解 3-oxo-C12 高丝氨酸内酯。C6- 和 C12-HSL 在被 OA22 降解后的酸回收表明分离物中存在内酯酶。OA10 的无细胞上清液用乙酸乙酯萃取，得到群体淬灭化合物。以多种方式证明了用 OA10 提取物处理的 C. violaceum MK 中的色素抑制作用，表明提取物的 QSI 活性，而群体感应信号分子没有降解。通过16S核糖体DNA序列分析，分离株OA22和OA10分别被鉴定为Desemzia incerta和Bacillus sp.。OA10 的无细胞上清液用乙酸乙酯萃取，得到群体淬灭化合物。以多种方式证明了用 OA10 提取物处理的 C. violaceum MK 中的色素抑制作用，表明提取物的 QSI 活性，而群体感应信号分子没有降解。通过16S核糖体DNA序列分析，分离株OA22和OA10分别被鉴定为Desemzia incerta和Bacillus sp.。OA10 的无细胞上清液用乙酸乙酯萃取，得到群体淬灭化合物。以多种方式证明了用 OA10 提取物处理的 C. violaceum MK 中的色素抑制作用，表明提取物的 QSI 活性，而群体感应信号分子没有降解。通过16S核糖体DNA序列分析，分离株OA22和OA10分别被鉴定为Desemzia incerta和Bacillus sp.。