MUTAGENS WHICH CAUSE DELETIONS IN ESCHERICHIA COLI

5S rRNA gene deletions cause an unexpectedly high fitness loss in Escherichia coli.

In Escherichia coli, ribosomal RNAs (16S, 23S and 5S) are co-transcribed in a highly regulated manner from seven genomically dispersed operons. Previous studies on the cellular effects of altered levels of two of these rRNAs (16S and 23S) have been useful in better understanding the regulation of rRNA expression. Furthering these studies, we have investigated the effect of 5S rRNA deficiencies ...

Context effects in the formation of deletions in Escherichia coli.

We have examined the frequency with which identical deletions are formed in different chromosomal contexts. A panel of six mutant bla genes containing palindrome/direct repeat structures were moved from pBR322 to three locations: at lambda att, at chromosomal lac, and at F'lac. Deletion of the palindromes and one of the direct repeats results in reversion to Ampr. The frequency of deletion for ...

Analysis of O-island deletions in Escherichia coli O157:H7

Construction of consecutive deletions of the Escherichia coli chromosome

The minimal set of genetic information necessary and sufficient to sustain a functioning cell contains not only trans-acting genes, but also cis-acting chromosomal regions that cannot be complemented by plasmids carrying these regions. In Escherichia coli (E. coli), only one chromosomal region, the origin of replication has been identified to be cis-acting. We constructed a series of mutants wi...

Do urethral Escherichia coli cause abacterial cystitis?

To determine whether Escherichia coli in or near the urethra caused symptoms of abacterial cystitis, the results of serial cultures from the vaginal introitus of 92 patients with recurrent cystitis were compared with symptoms at clinic visits when they were abacteriuric. Similar comparisons were made in 15 of these patients using cultures from the external urethral meatus and proximal urethra. ...