University of Illinois Urbana-Champaign

Lactose Operon Expression and Plasmid Rearrangement in Rhodopseudomonas Sphaeroides (Gram Negative Bacteria)

Nano, Francis Edward

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https://hdl.handle.net/2142/71160

Description

Title
Lactose Operon Expression and Plasmid Rearrangement in Rhodopseudomonas Sphaeroides (Gram Negative Bacteria)
Author(s)
Nano, Francis Edward
Issue Date
1984
Department of Study
Microbiology
Discipline
Microbiology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Microbiology
Abstract
  • Genetic tools were developed to study gene regulation in Rhodopseudomonas sphaeroides. In initial studies expression of the transposable lac operon, Tn951, was examined. Very low levels of (beta)-galactosidase were observed in R. sphaeroides but mutants of this bacterium were recovered that were able to use lactose as the sole carbon source and which had elevated (beta)-galactosidase expression. The mutation allowing growth on lactose was determined to be on the R. sphaeroides endogenote and not on Tn951 DNA.
  • In an effort to experimentally approach an understanding of transcriptional regulation in R. sphaeroides Mu dl(Ap('R), lac) was introduced via the R-plasmid, R751. The introduction of Mu dl(Ap('R), lac) was found to enhance the appearance of photosynthetic deficient mutants of R. sphaeroides; Mu dl(Ap('R), lac) DNA was found not to be physically associated with endogenote DNA. In many of the photosynthetic mutants the indigenous R. sphaeroides plasmid were found to be rearranged. It was further discovered that the plasmids involved in the rearrangements had extensive DNA homology.
  • In another approach to understanding gene regulation in R. sphaeroides a broad host range plasmid was constructed that permitted the translational fusion of target DNA to the lac operon. R. sphaeroides DNA was cloned into this plasmid and recombinant plasmids were introduced into R. sphaeroides. Several isolates were recovered that produced various levels of (beta)-galactosidase, presumably representing the cloning of various R. sphaeroides promoters.
Graduation Semester
1984
Type of Resource
text
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http://hdl.handle.net/2142/71160

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