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Full-Text Articles in Molecular Biology

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan Dec 1990

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan

Electronic Theses and Dissertations

A temperature-sensitive mutant of Escherichia coli affected in the alpha subunit of RNA polymerase has been investigated. Gene mapping and complementation experiments placed the mutation to temperature-sensitivity within the alpha operon at 72 min on the bacterial chromosome. The rate of RNA synthesis in vivo and the accumulation of ribosomal RNA were significantly reduced in the mutant at 44$\sp\circ$C. The thermostability at 44$\sp\circ$C of the purified holoenzyme from mutant cells was about 20% of that of the normal enzyme. Assays with T7 DNA as a template showed that the fraction of active enzyme competent ...


A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng Jan 1990

A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng

Retrospective Theses and Dissertations

An RFLP map was constructed for Cochliobolus heterostrophus, the causal agent of southern corn leaf blight, to facilitate the cloning of pathogenicity genes. A total of 128 RFLP and 4 phenotypic markers were analyzed. Of these, 126 were linked to other markers and delimited 944 cM, or, at a maximum, 58% of the total map length. Several RFLPs were found tightly linked to Tox1, a pathogenicity gene. A previously hypothesized translocation tightly linked to Tox1 was also detected;The numbers and sizes of the chromosomes of the two strains crossed to make the RFLP map were investigated using pulsed field ...


Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson Jan 1990

Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson

Retrospective Theses and Dissertations

Mutations at the suppressor of forked, su(f), locus are trans-acting, allele specific suppressors and enhancers of mutations at certain other loci. Su(f) is a trans-acting regulator whose normal product is necessary for proper transcription of these genes. The su(f) product regulates the transcription of transposable elements located within these genes. Our investigation includes a genetic analysis in which a number of new su(f) alleles were isolated, a development analysis in which the effects of new alleles and allelic combinations were characterized, and a molecular analysis in which a cloned genomic DNA fragment containing su(f) was ...