Indonesia is the third largest producer of fish and other aquaculture products in the world, making this industry a major contributor in the economy of Indonesia. However, this industry continually overcome challenges, one of them are bacterial outbreaks. In addition, the emergence of these bacterial outbreaks were worsen due to the biofilm produced by many significant pathogenic bacteria and the impact of increased antibiotic resistance. These issues have become a global concern, because antibiotics are currently one of the main treatments available to overcome this problems. Therefore, studies aimed at finding and characterizing bioactive compounds to combat these issues. In this study actinomycetes isolates were screened and characterized for their bioactive compounds produced which have inhibitory and destructive activity and also QS inhibitors against biofilm structure of aquatic pathogenic bacteria, such as Vibrio harveyi, A. hydrophila, and S. agalactiae. Extracts (20 mg/mL) produced by sixteen Actinomycetes isolates showed anti-quorum sensing activity towards reporter stain Chromobacterium violaceum wild-type. Most of these extracts showed better inhibitory activity on all of the pathogenic bacteria biofilm structure tested than the destructive activity on the preformed of those biofilm structure. Subsequently, we also performed characterization of bioactive compound and found that in this study, polysaccharide is the most common antibiofilm agents, which were responsible to their antibiofilm activity. Finally, we found that the value of LC50 of all extracts tested were more than 1 mg/mL, thereby all of extracts tested did not show cyto-toxic effect against Artemia salina. All of the extracts of Actinomycetes isolates showed promising inhibitory activity towards biofilm structure of pathogenic bacteria tested. So far, all of the extracts are potential to be QS inhibitors and antibiofilm agents of all pathogenic bacteria tested.

中文翻译：

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放线菌分离物抗水产养殖病原菌抗生物膜及抗群体感应活性的筛选

印度尼西亚是世界第三大鱼类和其他水产养殖产品生产国，使该行业成为印度尼西亚经济的主要贡献者。然而，该行业不断克服挑战，其中之一是细菌爆发。此外，由于许多重要病原菌产生的生物膜和抗生素耐药性增加的影响，这些细菌爆发的出现更加恶化。这些问题已成为全球关注的问题，因为抗生素是目前可用于克服这些问题的主要治疗方法之一。因此，研究旨在寻找和表征生物活性化合物以解决这些问题。在这项研究中，对放线菌分离株进行了筛选和表征，其产生的生物活性化合物具有抑制和破坏活性，以及​​对水生致病菌（如哈维弧菌、嗜水链球菌和无乳链球菌）生物膜结构的 QS 抑制剂。由 16 株放线菌分离株产生的提取物 (20 mg/mL) 对报告基因染色的紫色色杆菌野生型显示出抗群体感应活性。大多数这些提取物对所有测试的病原菌生物膜结构显示出比对这些生物膜结构预成型的破坏活性更好的抑制活性。随后，我们还对生物活性化合物进行了表征，发现在本研究中，多糖是最常见的抗生物膜剂，是其抗生物膜活性的原因。最后，我们发现所有测试提取物的 LC50 值均超过 1 mg/mL，因此所有测试提取物均未显示对卤虫的细胞毒性作用。放线菌分离物的所有提取物都对所测试的病原菌的生物膜结构显示出有希望的抑制活性。到目前为止，所有提取物都有可能成为所有测试病原菌的 QS 抑制剂和抗生物膜剂。