Deleting Two-thirds of the C-terminus Alpha Domain Region in Autotransporter Antigen 43 is Associated with Increased Aggregation and Biofilm Formation in DH5α Escherichia coli
Abstract
Antigen 43 is an autotransporter protein present in Escherichia coli associated with bacterial aggregation and biofilm formation. This protein is extensively studied due to its involvement in bacterial pathogenesis and antibiotic resistance. However, the specific role of the C-terminus alpha domain region of Antigen 43 in aggregation and biofilm formation has yet to be fully elucidated. In this study, we investigated the impact of deleting two-thirds of the C-terminus alpha domain region in Antigen 43 on aggregation and biofilm formation, specifically in the DH5α Escherichia coli strain. These DH5α cells were transformed with plasmids containing either full-length Antigen 43 (wild type) or the partially deleted Antigen 43 (mutant) construct and transformation was confirmed via western blot analysis. Aggregation assays were conducted using phosphate-buffered saline suspensions at pH 5, 6, and 7 for the wild-type strain and at a pH of 5 to compare between the wild type and mutant strains. Additionally, using a crystal violet assay, biofilm formation of the mutant strain was assessed and compared relative to the wild type strain. Our results demonstrated that Antigen 43 mutant cells exhibited greater aggregation compared to wild type and empty vector strains through observing cells clumping in test tubes and optical density readings in aggregation assays. Likewise, biofilm formation assays showed a similar trend, indicating enhanced biofilm formation in the mutant strain. These findings suggest that deletion of two-thirds of the C-terminus alpha domain region in Antigen 43 enhances aggregation and biofilm formation in DH5α E. coli. This prompts further investigation into the underlying mechanisms driving these observations and its implications for pathogenesis and antimicrobial resistance in bacterial cells displaying Antigen 43 on their cell surface.
