科罗拉多大学Aaron T. Whiteley研究组近日取得一项新成果。经过不懈努力，他们报道了功能性淀粉样蛋白赋予防御掠食性细菌的能力。该研究于2025年7月2日发表于国际一流学术期刊《自然》杂志上。

在这里，研究团队筛选了一系列不同的大肠杆菌菌株对B.细菌的抗性，并发现大约三分之一的菌株通过产生卷曲纤维来抵抗捕食。卷曲纤维是功能性淀粉样蛋白CsgA的低聚物，非常耐用。利用遗传学和显微镜，课题组研究人员证明卷曲纤维提供了一个屏障，保护易感细胞独立于生物膜形成所需的基因。这一屏障进一步保护大肠杆菌免受黏液球菌、黄原菌和选择性噬菌体的攻击。细菌淀粉样蛋白的生物信息学分析表明，这些系统在双层细菌（既有内膜又有外膜的细菌）中是多样化和广泛存在的。其中一种是由铜绿假单胞菌编码的进化上独特的淀粉样蛋白，它也可以保护它们免受B.细菌的侵害。这项工作表明，功能性淀粉样蛋白可以保护细菌免受各种威胁。

据悉，Bdellovibrio bacteriovorthem是一种掠食性细菌，其非选择性地捕食革兰氏阴性细菌，通过侵入被捕食细胞的周质，滤出宿主的营养物质，并最终裂解被感染的细胞以退出并寻找新的宿主。在许多方面，它们的捕食生命周期与噬菌体相似。然而，与噬菌体防御不同，对它们的防御尚未得到广泛研究。

附：英文原文

Title: Functional amyloid proteins confer defence against predatory bacteria

Author: Ledvina, Hannah E., Sayegh, Ryan, Carale, Ricardo O., Burroughs, A. Maxwell, Macklin, Alexa R., Azadeh, Ashley L., Borja Najera, Layla D., Aravind, L., Whiteley, Aaron T.

Issue&Volume: 2025-07-02

Abstract: Bdellovibrio bacteriovorus is a predatory bacterium that non-selectively preys on Gram-negative bacteria by invading the prey-cell periplasm, leaching host nutrients and ultimately lysing the infected cell to exit and find a new host1,2. The predatory life cycle of B. bacteriovorus is, in many ways, comparable to a bacteriophage. However, unlike phage defence, defence against B. bacteriovorus has not been widely investigated. Here we screened a collection of diverse Escherichia coli strains for resistance to B. bacteriovorus and identified that roughly one-third of strains robustly defended against predation by producing curli fibres. Curli fibres are oligomers of the functional amyloid protein CsgA, which is exceptionally durable3. Using genetics and microscopy, we demonstrate that curli fibres provide a barrier that protects susceptible cells independent of genes required for biofilm formation. This barrier further protected E. coli against attack by the predatory bacterium Myxococcus xanthus and select phages. Bioinformatic analysis of bacterial amyloids showed these systems are diverse and widespread in diderm bacteria (those with both inner and outer membranes). One of these, an evolutionarily distinct amyloid encoded by Pseudomonas aeruginosa, also protected against B. bacteriovorus. This work establishes that functional amyloids defend bacteria against a wide range of threats.

DOI: 10.1038/s41586-025-09204-7

Source: https://www.nature.com/articles/s41586-025-09204-7