Department of Cell and Molecular Biology, Microbiology, University of Gothenburg, Goteborg, Sweden.
Biofouling. 2011 Jul;27(6):579-88. doi: 10.1080/08927014.2011.589001.
Bacteria associated with seaweeds can both harm and benefit their hosts. Many seaweed species are known to produce compounds that inhibit growth of bacterial isolates, but the ecological role of seaweed metabolites for the associated bacterial community structure is not well understood. In this study the response of a colonizing bacterial community to the secondary metabolite (1,1,3,3-tetrabromo-2-heptanone) from the red alga Bonnemaisonia hamifera was investigated by using field panels coated with the metabolite at a range of concentrations covering those measured at the algal surface. The seaweed metabolite has previously been shown to have antibacterial effects. The metabolite significantly affected the natural fouling community by (i) altering the composition, (ii) altering the diversity by increasing the evenness and (iii) decreasing the density, as measured by terminal restriction fragment length polymorphism in conjunction with clone libraries of the 16S rRNA genes and by bacterial enumeration. No single major bacterial taxon (phylum, class) was particularly affected by the metabolite. Instead changes in community composition were observed at a more detailed phylogenetic level. This indicates a broad specificity of the seaweed metabolite against bacterial colonization, which is supported by the observation that the bacterial density was significantly affected at a lower concentration (0.02 μg cm⁻²) than the composition (1-2.5 μg cm⁻²) and the evenness (5 μg cm⁻²) of the bacterial communities. Altogether, the results emphasize the role of secondary metabolites for control of the density and structure of seaweed-associated bacterial communities.
与海藻相关的细菌既可能对其宿主造成伤害，也可能带来益处。许多海藻物种都被发现能够产生抑制细菌分离株生长的化合物，但海藻代谢物对相关细菌群落结构的生态作用还不是很清楚。在这项研究中，通过使用 Field Panels （现场面板），在一系列浓度下（包括在海藻表面测量到的浓度）覆盖了该二次代谢物（1,1,3,3-四溴-2-庚酮），研究了定殖细菌群落对红藻 Bonnemaisonia hamifera 次生代谢物的响应。该海藻代谢物先前已显示出具有抗菌作用。该代谢物通过以下方式显著影响了自然污损生物群落：（i）改变组成；（ii）通过增加均匀度来改变多样性；（iii）通过末端限制性片段长度多态性（T-RFLP）结合 16S rRNA 基因的克隆文库和细菌计数，降低密度。没有一个主要的细菌分类群（门、纲）受到代谢物的特别影响。相反，在更详细的系统发育水平上观察到了群落组成的变化。这表明海藻代谢物对细菌定殖具有广泛的特异性，这一观点得到了以下观察结果的支持：在较低浓度（0.02μg cm⁻²）下，细菌密度受到显著影响，而在组成（1-2.5μg cm⁻²）和均匀度（5μg cm⁻²）方面受到的影响较小。总之，这些结果强调了次生代谢物对控制海藻相关细菌群落密度和结构的作用。
