Affiliation:
1. Biochemistry Department, University of Sydney, Sydney N.S.W., Australia
Abstract
Origin:terminus genetic marker ratios (both
purA: metB
and
purA:ilvA
) were measured in extracts of spores of
Bacillus subtilis
strains W23
thy his
and 168
thy
. For strain W23
thy his
, normalized to W23 spore deoxyribonucleic acid, both ratios were equal to unity and were consistent with the presence of only completed chromosomes in the spores. The same ratios in extracts of spores of 168
thy
, normalized to strain 168 or the prototroph SB19, were abnormal, i.e., 2.26 ± 0.10 and 0.71 ± 0.06 for
purA:metB
and
purA:ilvA
, respectively. These values were unaffected by the extent of extraction of the spore deoxyribonucleic acid, the richness of the medium on which they are formed, and the thymine phenotype. The high ratio for
purA:metB
is in agreement with the results of earlier workers but, because of the low
purA:ilvA
ratio, cannot be explained simply by the presence of partially replicated chromosomes in spores of strain 168
thy
. Furthermore,
purA:leuA
in such extracts is 1.01 ± 0.06, consistent with the presence of only completed chromosomes. It is concluded that the abnormal origin:terminus marker ratios are only apparent and result from non-isogenicity between strains 168
thy
and 168 in the
metB thyB ilvA
chromosome region introduced during construction of 168
thy
by transformation of strain 168 with W23
thy
deoxyribonucleic acid. It is concluded further that the chromosomes of strain 168
thy
spores are in a completed form.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference14 articles.
1. Dennis E. S. and R. G. Wake. 1968. The Bacillus subtilis genome-studies on its size and structure p. 61-70. In W. J. Peacock and R. D. Brock (ed.) Replication and recombination of genetic material. Australian Academy of Sciences Canberra.
2. Velocity of chromosome replication in thymine-requiring and independent strains of Bacillus subtilis;Ephrati-Elizur E.;J. Bacteriol.,1971
3. Transformable thymine-requiring mutant of Bacillus subtilis;Farmer J. L.;J. Bacteriol.,1965
4. Comparison of species and varieties of the genus Bacillus: structure and nucleic acid content of spores;Fitz-James P. C.;J. Bacteriol.,1959
5. Location of genetic loci of ribosomal RNA on Bacillus subtilis chromosome;Oishi M.;Proc. Nat. Acad. Sci. U.S.A.,1965
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