Use this URL to cite or link to this record in EThOS:
Title: Phenotypic and molecular genetic studies on the production of the calcium-dependent antibiotic of Streptomyces coelicolor A3(2)
Author: Podmore, S. M.
ISNI:       0000 0004 2679 0389
Awarding Body: The University of Manchester
Current Institution: University of Manchester
Date of Award: 1995
Availability of Full Text:
Access from EThOS:
In this study, several attempts were made to clone cda genes by using the high-copy-number plasmid vector, pIJ486. Three cloning strategies were employed: (i) cloning by complementation of CDA non-producing S. coelicolor mutants; (ii) cloning of biosynthetic and/or regulatory genes using S. lividans as host and, (iii) cloning CDA resistance gene(s) into a heterologous host, Streptomyces griseofuscus. No cda clones were isolated using the three methods. A novel high-frequency switching phenomenon was discovered while attempting to clone cda genes by complementation of strain 2755 (cda-l). It was found that transformation of 2755 with particular pIJ101-derived plasmids increased the frequency of reversion to the Cda⁺ phenotype by at least 10-fold. The common denominator from the plasmids causing increased instability of the Cda phenotype was that all were defective in their replication functions due to the lack of a functional sti (for strong incompatibility) sequence and as a result cells harbouring them accumulated single-stranded DNA. Furthermore, this work demonstrated that the Cda+/- phenotypes of some cda mutants (designated Class I) were highly revertible (in both directions). During the course of this study, three PCR products had been isolated from S. coelicolor using PCR primers designed against conserved sequences of peptide synthetase (PS) enzymes. They were all found to hybridise to the "10 o'clock" region of the S. coelicolor chromosome and several cosmids were identified from the "Redenbach" cosmid library which hybridise with the PCR products.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available