| dc.contributor.author | Yang, Keqian. | en_US |
| dc.date.accessioned | 2014-10-21T12:33:44Z | |
| dc.date.available | 1993 | |
| dc.date.issued | 1993 | en_US |
| dc.identifier.other | AAINN93758 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55401 | |
| dc.description | Streptomyces griseoviridus showed a low level of etamycin resistance before the onset of etamycin production, and a higher level of resistance after its onset. | en_US |
| dc.description | Streptomyces griseofuscus was chosen as the host for expression of cloned etamycin resistance determinants. It was inherently sensitive to etamycin, but exhibited low-level resistance after induction by the antibiotic. A search for ermE-hybridizing DNA in S. griseoviridus identified SalI fragments of 0.6 and 4.3 kb. The 4.3-kb fragment was cloned within a 17.4-kb segment of genomic DNA and the ermE-hybridizing region was sequenced. The 0.6-kb fragment was not present on the 17.4-kb segment and was not investigated. A region within the cloned 4.3-kb fragment showed a high degree of nucleotide sequence similarity to ermE, but did not encode an ErmE-like product. When introduced into S. griseofuscus in the Streptomyces-E. coli shuttle vector pHJL400, the 17.4-kb fragment conferred significantly higher etamycin resistance than was observed in transformants containing pHJL400 alone. The resistance phenotype associated with the 17.4-kb fragment was conferred in part by a 2.1-kb sub-fragment. By sequencing this sub-fragment, two intact ORFs were identified. Database searches failed to associate the ORF products with any known resistance genes. Overall, the results suggested that the elevated etamycin resistance conferred by the 17.4-kb fragment and by several other cloned DNA fragments was due to activation of an indigenous etamycin resistance gene in the host. | en_US |
| dc.description | Streptomyces lividans was shown to possess an etamycin-inactivating enzyme. S. griseofuscus showed "temporal" resistance to erythromycin and lincomycin. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1993. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Molecular. | en_US |
| dc.subject | Biology, Microbiology. | en_US |
| dc.subject | Health Sciences, Pharmacology. | en_US |
| dc.title | Etamycin resistance in Streptomyces. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
