CONSERVED GENETIC REGIONS WITHIN THE BACILLUS CHROMOSOME.
Item
-
Title
-
CONSERVED GENETIC REGIONS WITHIN THE BACILLUS CHROMOSOME.
-
Identifier
-
AAI8401901
-
identifier
-
8401901
-
Creator
-
GOTTLIEB, PAUL JEFFREY.
-
Contributor
-
Rivka Rudner
-
Date
-
1984
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, Genetics
-
Abstract
-
This project analyzed conserved genomic sequences in eight members of the genus Bacillus. As in earlier studies (Dubnau et al., 1965a; Chilton and McCarthy, 1969), conserved genetic regions resistant to evolutionary change are noted, consisting of rRNA gene sets and nearby antibiotic resistance markers. Two families of these genes exist in the Bacillus species and strains analyzed. They differ in the presence or absence of an EcoRI sensitive site in the 5' end of the 23S gene sequence. This site is present in B. subtilis and B. licheniformis and absent in B. globigii, B. pumilus, and B. amyloliquefaciens. Each species has only one type 23S sequence in all its multiple rRNA cistrons, indicating a gene divergence occurred in addition to an amplification event. Otherwise, physical organization of the repeating rRNA gene sets in the genus Bacillus is conserved. Two abutment regions were found between all 16S and 23S determinants differing by 0.2 Kbp, the larger presumably containing tRNA sequences.;More extensive sequence divergences occur beyond the boundaries of the ribosomal RNA cistrons. Differences between strains of the same species were examined in B. subtilis and B. licheniformis.;We observed the conservation of the leucine gene first reported by Dubnau et al. (1965a) and Chilton and McCarthy (1969). Species capable of interspecific transformation of B. subtilis leu('-) recipients displayed greater Southern blot hybridization intensity compared to nontransforming species, when examined with a cloned leucine sequence. In contrast threonine and tryptophan markers were incapable of any interspecific transformation. Hybridization intensity of a cloned threonine sequence was less than that of leucine. A cloned B. pumilus tryptophan sequence hybridized with heterologous DNA only from B. subtilis and B. licheniformis.;Strains of B. subtilis were observed that have deletions of rRNA cistrons. Alterations were associated with a variety of mutations within the arg and leu region of the chromosome, and have led us to postulate the presence of a second rRNA gene cluster. The conservation of leu could be due to its association with conserved ribosomal genes.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
-
Program
-
Biology
