Abstract

The genes folA and thyA have a key role in cell growth, as they are involved in the biosynthesis of folate cofactors directly and/or indirectly. The study of the relationship between these two genes will improve our understanding of cell growth. The effects of folA and thyA on the growth of Escherichia coli cells were studied and the results showed that the absence of the folA gene affects the growth of cell. WithoutfolA cells are not able to grow or grow very poorly; however, folA has no effect on phenotype of strains harboring thyA + or thy - mutation. Also, different thyA alleles ( thyA - and thy ts ) do not affect the growth of EfolA::Kan3 strains. In addition, thin aggregative fimbriae (curli) protein by some of our E. coli K-12 lab strains resulted in improved growth in minimal medium compared to their parent. I developed assay for the presence of the CsgA subunit of curli protein in these strains via a rapid purification method (Collinson et al, 1992) and SDS-agarose gel electrophoresis (Horsten, 2003; Bagriantsev et al. 2006). This is a very fast and affective method to detect the presence of curli protein compared to other time consuming methods, such as western blotting and SDS-PAGE, and protein binding assays. Using this "rapid curli assay" I was able to detect the curli protein in the wells of SDS-agarose gels and identify the CsgA protein band of the recovered materials from this gel in a SDS-PAGE gel