Extracellular products as mediators of the formation and detachment of Pseudomonas fluorescens biofilms.
Extracellular products as mediators of the formation and detachment of Pseudomonas fluorescens biofilms.
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DOI：
10.1111/j.1574-6968.1998.tb13225.x
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发表时间：
1998-10
影响因子：
2.1
通讯作者：
D. Allison;Begoña Ruiz;C. Sanjosé;A. Jaspe;P. Gilbert
中科院分区：
文献类型：
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作者：
D. Allison;Begoña Ruiz;C. Sanjosé;A. Jaspe;P. Gilbert
荧光假单胞菌B52在21 ℃下在垂直夹紧并部分浸没在液体培养基中的玻璃盖玻片的空气/液体/固体界面处产生大量生物膜。生物膜的形成是最大的ca。接种液体培养基后20-50 h，如环境扫描电子显微镜（ESEM）所示，含有大量的细菌细胞，这些细胞嵌入广泛的外聚合物基质中。孵育超过50小时导致生物膜的减少，ESEM主要与外聚合物的损失有关。生物膜的形成和随后的外聚合物沉积的下降都更快，并且当来自两天龄的B52培养物的上清液用作初始生长培养基时，发生的程度更大。向新鲜生长培养基中添加N-酰基-己酰基高丝氨酸内酯对生物膜形成具有与使用用过的培养基类似的作用。通过根癌农杆菌生物测定法，在用过的培养物上清液中不能证明高丝氨酸内酯。在取自致密生物膜培养物的消耗培养基中检测到胞外多糖裂解酶，其作用特异性针对生物膜胞外多糖。结果表明：（i）细胞-细胞信号（如高丝氨酸内酯）与荧光假单胞菌生物膜的形成有关，（ii）外聚合物的酶降解在饥饿条件下细胞的脱离中具有特定作用，以及（iii）虽然短链（C6）外源高丝氨酸可以在荧光假单胞菌中触发这种反应，其自身的信号物质可能具有较长的（> C8）脂肪酰基链。
Pseudomonas fluorescens B52 produces substantial biofilms at the air/liquid/solid interface of glass coverslips clamped vertically and partly submerged in liquid medium at 21 degrees C. Biofilm formation was maximal ca. 20-50 h after inoculation of the liquid medium and as indicated by environmental scanning electron microscopy (ESEM), contained large numbers of bacterial cells that were embedded within an extensive exopolymeric matrix. Incubation beyond 50 h led to reductions in biofilm which ESEM related primarily to losses of exopolymer. Both biofilm formation and the subsequent decline in exopolymer deposition was more rapid, and occurred to greater extents, when supernatants from two-day old cultures of B52 were used as the initial growth media. The addition of N-acyl-hexanoyl homoserine lactone to fresh growth medium had a similar effect upon biofilm formation as using spent culture medium. Homoserine lactones could not be demonstrated in spent culture supernatants by an Agrobacterium tumefaciens bioassay. An exopolysaccharide lyase was detected in spend culture media taken from dense biofilm cultures whose action was specifically directed towards biofilm exopolysaccharide. Results suggest that (i) cell-cell signals such as homoserine lactones are associated with the formation of P. fluorescens biofilms, (ii) the enzymic degradation of exopolymers has a specific role in the detachment of cells under starvation conditions, and (iii) whilst short chain (C6) exogenous homoserines can trigger such response in P. fluorescens, its own signal substance is likely to possess a longer (> C8) fatty acyl chain.