Digital Commons Network^™

Variants And Polymorphisms Of Three Repetitive Dna Families In The Human Genome, Robert M. Roudabush

Electronic Theses and Dissertations

A novel 0.6 kb LINE family in human DNA, designated L2Hs, has been described (Musich and Dykes 1986). Studies employing clone N6.4, containing three 0.6 kb segments of this family, indicate that these sequences are interspersed and moderately repetitive. Two additional variant sequences of the L2Hs family, N6.1 and N6.3, have been identified. Restriction mapping of each cloned segment indicates similarities among N6.4, N6.3 and N6.1. When the cloned DNAs were cleaved with restriction enzymes and subjected to cross-hybridization, each cloned insert produced a pattern indicating that the sequences contained in N6.1 and N6.3 are represented in at least one …

Identification Of The Functional Regions Of The Yeast Activator Adr1, Lynne Taylor Bemis

Doctoral Dissertations

ADR1, a transcriptional activator from the yeast Saccharomyces cerevisiae, is required for activation of the glucose-repressible alcohol dehydrogenase, ADH II (encoded by the ADH2 gene). The ADR1 gene encodes a protein which binds to an upstream activation sequence in the ADH2 promoter. Several methods were used to locate functional regions of the ADR1 protein.

The adr1-1 mutation was identified as a C to G transversion resulting in a nonsense codon at the eleventh codon of ADR1. tRNA-suppressors which substituted an amino acid at the eleventh codon of adr1-1 resulted in a functional adr1-1 protein, indicating that the translational start of …

Characterization Of Cell Cycle Changes In Polyamine-Depleted Hela Cells, Robert Anthony Koza

Doctoral Dissertations

HeLa cells were synchronized for S-phase DNA synthesis and simultaneously depleted of polyamines by the addition of the inhibitor of polyamine biosynthesis, $\alpha$-difluoromethylornithine (DFMO).

DFMO reacts catalytically with and irreversibly inhibits the enzyme ornithine decarboxylase (ODC) thereby preventing the biosynthesis of the polyamines putrescine, spermidine, and spermine.

The depletion of polyamines in HeLa cells inhibits cellular processes such as DNA synthesis and proliferation. These processes could be reversed by the addition of spermidine 10-12 hours before S-phase DNA synthesis was initiated.

Nuclear reconstitution procedures were utilized to determine the location of the deficiency in polyamine-depleted cell nuclei. It was shown …

Deoxyribonucleases Expressed In Competence-Induced Com And Spo0 Mutants Of Bacillus Subtilis, Billy Robert Mcgrew

Doctoral Dissertations

The inclusion of 1% casein in buffer used to reactivate enzymes subjected to SDS-polyacrylamide electrophoresis resulted in faster and more complete restoration of nuclease and B-galactosidase enzyme activities. Enzyme activities which were absent from gels during longer wash procedures were detectable with this technique. The threshold of detection of two-dimensionally separated Deoxyribonuclease I was 1 picogram, tenfold lower than for previously reported wash procedures. Addition of BSA at concentrations above 50 ug/ml to nuclease gels was found to result in less effective detergent removal during wash procedures and reduced recovery of enzyme activity.

General and specific nuclease expression patterns were …

Receptor Arrangement In Myoblasts And Model Membranes, Ingrid Evelyn Mehlhorn

Digitized Theses

Glycosphingolipids are the carbohydrate-bearing lipids of animal cell surfaces. They are being investigated for their structural effects, for their role as recognition sites for hormones, toxins, viruses, and for their involvement in cell-cell interactions. Their physical behaviour in membranes--i.e., their exposure, distribution, peculiar acyl chain characteristics, sugar headgroup arrangement, and interactions--have become questions of considerable debate since these are the very factors thought to regulate their roles as structural components and attachment/recognition sites.;A major interest for us has been to apply freeze-etch electron microscopy to receptor studies in membranes. We developed its use for glycoproteins in cultured cell membranes and …

Purification And Characterization Of Four Novel Proteases From The Periplasmic Space Of Escherichia Coli K12, Indrasen Sivalingam Vaithilingam

Digitized Theses

Intracellular proteases are ubiquitous in nature. This extensive distribution necessarily implicates their participation in a wide variety of cellular events. Escherichia coli, contains a variety of proteases and peptidases. For the most part, the known endoproteases of E. coli have been characterized from cells grown to stationary phase on enriched media. Surprisingly, no studies have addressed the question of what proteases are present in exponentially growing E. coli, despite the fact that significant protein turnover occurs.;Previous studies from this laboratory revealed the presence of a unique Ca{dollar}\sp{lcub}2+{rcub}{dollar}-activated proteolytic activity in E. coli. This activity was maximal in mid-log grown cells …

Regulation Of Cyclic-Amp-Dependent Protein Kinases During Skeletal Myogenesis, Ian Anthony Lorimer

Digitized Theses

L6 myoblasts are a permanent rat skeletal myoblast cell line which differentiates in culture to form multinucleate myotubes. The regulation of the levels of cAMP-dependent protein kinases during myogenesis in L6 was studied, as these enzymes have been proposed to be involved in the control of this process. Measurement of the mRNA levels for the type I regulatory subunit (R{dollar}\sb{lcub}\rm I{rcub}{dollar}) of cAMP-dependent protein kinase, and studies on the rates of transcription from the gene coding for this protein, showed that the increase in R{dollar}\sb{lcub}\rm I{rcub}{dollar} which occurs during myogenesis is is not regulated transcriptionally. Measurement of R{dollar}\sb{lcub}\rm I{rcub}{dollar} half-lives …

Characterization Of Alkylation Repair And Comparison To Other Stress-Inducible Phenomenon In Drosophila., Sami Noshir Guzder

LSU Historical Dissertations and Theses

Drosophila melanogaster employs methyltransferase protein(s) to repair lesions in alkylated DNA in vitro (Green and Deutsch, 1983). This investigation deals with the characterization of the methyltransferase protein(s), and their inducibility in the organism upon exposure to alkylating agents. Ammonium sulfate fractionation of crude extracts from pupae resulted in the enrichment (approximately 15-fold in both the 50% and 30% ammonium sulfate supernatants) of the methyltransferase activity(s). Proteins with molecular weights of 30 Kd and 19 Kd were evident by SDS-PAGE analysis of crude extracts; the 30 Kd and 19 Kd could be separated in the 50% ammonium sulfate supernatant and 30% …

Isolation And Characterization Of Human Ribosomal Protein Complementary-Dnas, John Bryan Lott

Digitized Theses

Ribosome biosynthesis serves as a model of organelle assembly and gene regulation in both prokaryotes and eukaryotes. In Escherichia coli the isolation and cloning of ribosomal RNA genes and ribosomal protein genes was a prerequisite to detailed investigations of expression of these genes. Research into ribosome biosynthesis in eukaryotes has lagged behind in part because of the lack of data on the structure of the genes and mRNAs for ribosomal proteins.;This thesis details experiments designed to identify genomic or cDNA clones that encode human ribosomal proteins. Two methods were employed to achieve the goal of obtaining full-length clones that would …

Effects Of Dietary Casein And Soy Protein On Lipoprotein Metabolism In Rabbits, Pramod Khosla

Digitized Theses

Rabbits fed low-fat, cholesterol-free, semi-purified diets containing casein become hypercholesterolemic, whereas rabbits whose diets contain soy protein, maintain low levels of plasma cholesterol. Experiments were carried out in attempts to further understand this phenomenon.;Time course studies showed that on being transferred from a Chow diet, plasma cholesterol levels increased markedly in casein-fed rabbits. The increase was particularly prominent in the LDL fraction, in which the cholesterol and protein increased appreciably in the first two weeks. Subsequently LDL cholesterol increased more slowly, and LDL protein levels held steady. In contrast rabbits transferred to soy protein maintained low levels of plasma cholesterol …