The spoilage bacterium has been identified as a quick and strong biofilm former in the dairy industry. In our previous study, intra-species variation in bacterial biofilms has been observed in diverse strains from different genetic backgrounds; however, the mechanisms driving the observed heterogeneity of biofilms remain to be determined. In this study, the genotype-phenotype evaluation of the heterogeneity in biofilm formation of four strains were examined. The heterogeneity in biofilm phenotype was accessed in aspects of bacterial growth and motility, cell viability, biofilm matrix production, and biofilm architectures. The underlying mechanisms of the intra-species variability in biofilms were also explored by whole genome resequencing (WGR). Results from bacterial motility tests showed a diverse motility among the strains, but there was no clear correlation between bacterial motility and biofilm formation. The cell viability results showed a different number of live cells in biofilms at the intra-species level. Analysis of chemical components in biofilm matrix demonstrated the great intra-species differences regarding extracellular matrix composition, and a negative correlation between biofilm formation on stainless steel and the protein: carbohydrate ratio in biofilm matrix was observed. Confocal laser scanning microscopy analysis also revealed the intra-species variability by showing great differences in general properties of biofilms. WGR results identified important pathways involved in biofilm formation, such as two-component systems, quorum sensing, starch and sucrose metabolism, ABC transporters, glyoxylate and dicarboxylate metabolism, purine metabolism, and a phosphotransferase system. Overall, the above results emphasize the necessity of exploring the intra-species variation in biofilms, and would provide in-depth knowledge for designing efficient biofilm control strategies in the dairy industry.

中文翻译：

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从乳制品中分离的不同地衣芽孢杆菌菌株生物膜形成异质性的基因型-表型评估

腐败细菌已被认为是乳制品行业中快速而强大的生物膜形成剂。在我们之前的研究中，在来自不同遗传背景的不同菌株中观察到细菌生物膜的种内变异。然而，驱动观察到的生物膜异质性的机制仍有待确定。在这项研究中，对四种菌株生物膜形成的异质性进行了基因型-表型评估。从细菌生长和运动性、细胞活力、生物膜基质产生和生物膜结构等方面评估生物膜表型的异质性。全基因组重测序（WGR）也探索了生物膜种内变异的潜在机制。细菌运动测试结果显示，菌株之间的运动存在差异，但细菌运动与生物膜形成之间没有明确的相关性。细胞活力结果显示，在种内水平上，生物膜中的活细胞数量不同。对生物膜基质中化学成分的分析表明，细胞外基质成分存在巨大的物种内差异，并且观察到不锈钢上的生物膜形成与生物膜基质中的蛋白质：碳水化合物比率之间呈负相关。共焦激光扫描显微镜分析还通过显示生物膜的一般特性的巨大差异揭示了物种内的变异性。 WGR 结果确定了参与生物膜形成的重要途径，例如双组分系统、群体感应、淀粉和蔗糖代谢、ABC 转运蛋白、乙醛酸和二羧酸代谢、嘌呤代谢和磷酸转移酶系统。总的来说，上述结果强调了探索生物膜物种内变异的必要性，并将为设计乳制品行业有效的生物膜控制策略提供深入的知识。