Pickens C Pete, Wang Dongyu, Pan Chongle, De León Kara B
School of Biological Sciences, University of Oklahoma, Norman, Oklahoma, USA.
School of Computer Science, University of Oklahoma, Norman, Oklahoma, USA.
J Bacteriol. 2025 Jan 31;207(1):e0037924. doi: 10.1128/jb.00379-24. Epub 2024 Dec 31.
Ubiquitous in nature, biofilms provide stability in a fluctuating environment and provide protection from stressors. Biofilms formed in industrial processes are exceedingly problematic and costly. While biofilms of sulfate-reducing bacteria in the environment are often beneficial because of their capacity to remove toxic metals from water, in industrial pipelines, these biofilms cause a major economic impact due to their involvement in metal and concrete corrosion. The mechanisms by which biofilms of sulfate-reducing bacteria form, however, are not well understood. Our previous work identified two proteins, named by their gene loci DVU1012 and DVU1545, as adhesins in the model sulfate-reducing bacterium, Hildenborough. Both proteins are localized to the cell surface and the presence of at least one of the proteins, with either being sufficient, is necessary for biofilm formation to occur. In this study, differences in cell attachment and early biofilm formation in single deletion mutants of these adhesins were identified. Cells lacking DVU1012 had a different attachment strategy from wild-type (WT) and ΔDVU1545 cells, more often attaching as single cells than aggregates, which indicated that DVU1012 was more important for cell-to-cell attachment. ΔDVU1545 cells had increased cell attachment compared to WT cells when grown in static cultures. To date, comparisons of the Hildenborough have been made to the large adhesion protein system in environmental pseudomonads. Yet, we and others have shown distinct mechanistic differences in the systems. We propose to name these proteins in Hildenborough biofilm formation system to facilitate comparisons.
Biofilms of sulfate-reducing bacteria contribute to biocorrosion, costing the United States hundreds of millions of dollars annually. In contrast, these biofilms can be used to bioremediate toxic heavy metals and to generate bioelectricity. As one of the most abundant groups of organisms on Earth, it is pertinent to better understand mechanistically how the biofilms of sulfate-reducing bacteria form so we may use this knowledge to help in efforts to mitigate biocorrosion, to promote bioremediation, and to produce clean energy. This study shows that the absence of either one of two biofilm adhesins impacts surface colonization by a sulfate-reducing bacterium, and that these two biofilm adhesins differ in their effect on cell attachment compared to other well-documented bacteria such as species.
生物膜在自然界中无处不在，能在波动的环境中提供稳定性，并抵御应激源。在工业生产过程中形成的生物膜会带来极大问题且成本高昂。虽然环境中硫酸盐还原菌形成的生物膜因其具有从水中去除有毒金属的能力而通常有益，但在工业管道中，这些生物膜因参与金属和混凝土腐蚀而造成重大经济影响。然而，硫酸盐还原菌生物膜形成的机制尚未得到充分了解。我们之前的研究在模式硫酸盐还原菌希登伯勒菌中鉴定出两种蛋白，根据其基因座命名为DVU1012和DVU1545，它们是黏附素。这两种蛋白都定位于细胞表面，且至少存在其中一种蛋白（任何一种都足够）是生物膜形成所必需的。在本研究中，我们鉴定了这些黏附素单缺失突变体中细胞附着和早期生物膜形成的差异。缺乏DVU1012的细胞与野生型（WT）和ΔDVU1545细胞具有不同的附着策略，它们更常以单细胞形式而非聚集体形式附着，这表明DVU1012对细胞间附着更为重要。在静态培养条件下生长时，与WT细胞相比，ΔDVU1545细胞的细胞附着有所增加。迄今为止，已将希登伯勒菌与环境假单胞菌中的大型黏附蛋白系统进行了比较。然而，我们和其他人已经表明这些系统在机制上存在明显差异。我们提议对希登伯勒菌生物膜形成系统中的这些蛋白进行命名，以方便比较。
硫酸盐还原菌的生物膜会导致生物腐蚀，每年给美国造成数亿美元的损失。相比之下，这些生物膜可用于生物修复有毒重金属并产生生物电。作为地球上数量最多的生物群体之一，从机制上更好地理解硫酸盐还原菌生物膜如何形成非常重要，这样我们就可以利用这些知识来帮助减轻生物腐蚀、促进生物修复并生产清洁能源。这项研究表明，两种生物膜黏附素中任何一种的缺失都会影响硫酸盐还原菌的表面定殖，并且与其他有充分记录的细菌（如某些物种）相比，这两种生物膜黏附素对细胞附着的影响有所不同。
