Department of Biology, Faculty of Science, J. E. Purkyně University in Ústí nad Labem, Pasteurova 15, CZ40096, Ústí nad Labem, Czech Republic.
Laboratory of Fungal Biology, Institute of Microbiology ASCR, v.v.i., Vídeňská 1083, CZ14220, Prague 4, Czech Republic.
Folia Microbiol (Praha). 2021 Feb;66(1):133-143. doi: 10.1007/s12223-020-00833-1. Epub 2020 Oct 26.
The microbial biofilms are ubiquitous in nature and represent important biological entities that affect various aspects of human life. As such, they attracted considerable attention during last decades, with the factors affecting the biofilm development being among the frequently studied topics. In our work, the biofilm was cultivated on the surface of polypropylene fibers in a nutrient medium inoculated by the suspension of two unsterile soils. The effects of ionic strength and valence of salt on the amount of the produced biofilm and on composition of biofilm microbial communities were investigated. The effect of valence was significant in some OTUs: Arthrobacter/Pseudarthrobacter/Paenarthrobacter and Bacillus with positive response to monovalent salt (KCl) and Streptomyces, Lysinibacillus, Pseudomonas, and Ensifer with positive response to divalent salt (MgSO). The significant preference for a certain concentration of salts was observed in the case of OTUs Agrobacterium, Bacillus (both 100 mM), and Brevundimonas (30 mM). A new quantification method based on measuring of oxidizable organic carbon in biofilm biomass, based on dichromate oxidation, was used. We compared the results obtained using this method with results of crystal violet destaining and measuring of extracted DNA concentration as proxies of the biofilm biomass. The dichromate oxidation is simple, inexpensive, and fast, and our results show that it may be more sensitive than crystal violet destaining. The highest biomass values tended to associate with high concentrations of the divalent salt. This trend was not observed in treatments where the monovalent salt was added. Our data confirm the importance of inorganic ions for biofilm composition and biomass accumulation.
微生物生物膜在自然界中无处不在，是影响人类生活各个方面的重要生物实体。因此，在过去几十年中，它们引起了相当大的关注，其中影响生物膜发展的因素是经常研究的课题之一。在我们的工作中，生物膜是在营养培养基中接种悬浮的两种未灭菌土壤的聚丙烯纤维表面上培养的。研究了离子强度和盐的价态对产生的生物膜量和生物膜微生物群落组成的影响。价态的影响在某些 OTUs 中是显著的：节杆菌/假节杆菌/节杆菌和芽孢杆菌对单价盐（KCl）有正响应，而链霉菌、赖氨酸芽孢杆菌、假单胞菌和固氮螺菌对二价盐（MgSO）有正响应。在 OTUs 中观察到对某些盐浓度的显著偏好，如根瘤菌、芽孢杆菌（均为 100mM）和短芽孢杆菌（30mM）。我们使用了一种基于重铬酸钾氧化测量生物膜生物量中可氧化有机碳的新定量方法。我们将该方法获得的结果与结晶紫褪色和提取 DNA 浓度作为生物膜生物量的替代物的结果进行了比较。重铬酸钾氧化法简单、廉价且快速，我们的结果表明，它可能比结晶紫褪色法更灵敏。最高的生物量值倾向于与二价盐的高浓度相关。在添加单价盐的处理中没有观察到这种趋势。我们的数据证实了无机离子对生物膜组成和生物量积累的重要性。
