Abstract Macroalgae host a dense bacterial epibiome forming surface biofilms, which act as a biological defense by protecting the surface from macrofoulers. During experimental cultivation of Halymenia floresii ( Rhodophyta, Halymeniales ) under Integrated MultiTrophic Aquaculture (IMTA), the culture tanks remained clean of any exogenous algal colonization, and the surface of the H. floresii thalli was remarkably free from any fouling organisms. The presence of Halymenia also appeared to restrict the establishment of opportunist green algae and the colonization of barnacles usually impairing the cultures. To date, nothing is known about the diversity and biological potential of H. floresii epibionts. Hence, to better understand their epiphytic bacterial community, surface-associated bacteria from distinct H. floresii samples, beach-cast, integrated multi trophic aquaculture cultivar, and cultivar cylinders, were isolated. Thirty-one axenic bacterial strains belonging to 3 phyla, 20 genera, and 25 species were identified by 16S rRNA gene sequencing. Following isolation, they were screened for the production of quorum sensing (QS) signals, since these communication signals play a vital role in biofilm formation. All, except one, isolates were identified as gram-negative; hence, acylated homoserine lactones (AHLs) were focused upon. Using the reporter strain Escherichia coli pSB406, the isolates were screened for their ability to induce luminescence. Of 31 isolates screened, 17 strains, including Pseudoalteromonas arabiensis, Pseudoalteromonas sp. (B5BC and B6.1BC), Pseudoalteromonas mariniglutinosa, Vibrio owensii, Tenacibaculum sp., Maribacter sp ., Spongiimicrobium salis, Aquimarina sp., Kordiimonas sp. , Alteromonas sp. (B12CC and B16CC), Roseobacter sp., Erythrobacter sp., Ruegeria lacuscaerulensis, and Epibacterium sp., exhibited the presence of extracellular QS signals. Thus, the presence of QS bacteria on the surface of H. floresii was demonstrated for the first time. Our results may open a new direction to investigate the host—QS bacteria interactions.

中文翻译：

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从墨西哥红藻 Halymenia floresii 筛选表面相关细菌的群体感应活动

摘要 大型藻类拥有致密的细菌表观生物群落，形成表面生物膜，通过保护表面免受大型污损物的侵害而起到生物防御的作用。在综合多营养水产养殖 (IMTA) 下对 Halymenia floresii (Rhodophyta, Halymeniales) 进行实验培养期间，培养箱保持清洁，没有任何外源藻类定植，并且 H. floresii 菌体表面没有任何污垢生物。Halymenia 的存在似乎也限制了机会主义绿藻的建立和藤壶的殖民，通常会损害文化。迄今为止，人们对 H. floresii epibion​​ts 的多样性和生物学潜力一无所知。因此，为了更好地了解它们的附生细菌群落，来自不同 H. floresii 样本的表面相关细菌、海滩铸造、分离出综合多营养水产养殖品种和品种缸。通过16S rRNA基因测序鉴定出31株无菌菌株，隶属于3门20属25种。隔离后，对它们进行了群体感应 (QS) 信号的筛选，因为这些通信信号在生物膜形成中起着至关重要的作用。除一种外，所有分离株均被鉴定为革兰氏阴性；因此，酰化高丝氨酸内酯 (AHL) 受到关注。使用报告菌株大肠杆菌 pSB406，筛选分离株的诱导发光能力。在筛选出的 31 个分离株中，有 17 个菌株，包括 Pseudoalteromonas arabiensis、Pseudoalteromonas sp。（B5BC 和 B6.1BC）、马里尼格鲁丁酸假交替单胞菌、欧氏弧菌、Tenacibaculum sp.、Maribacter sp.、Spongiimicrobium salis、Aquimarina sp., Kordiimonas sp. ，交替单胞菌属。（B12CC 和 B16CC）、玫瑰杆菌属、红杆菌属、Ruegeria lacuscaerulensis 和 Epibacterium sp. 表现出细胞外 QS 信号的存在。因此，首次证明了弗洛雷斯菌表面存在 QS 细菌。我们的结果可能为研究宿主-QS 细菌相互作用开辟了一个新方向。