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Articles 1 - 10 of 10

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Isolation And Characterization Of Cdna Clones For Chicken Major Histocompatibility Complex Class Ii Molecules , Aree Moon Sung Jan 1989

Isolation And Characterization Of Cdna Clones For Chicken Major Histocompatibility Complex Class Ii Molecules , Aree Moon Sung

Retrospective Theses and Dissertations

The major histocompatibility complex (MHC) is a group of genes coding for molecules that provide the context for the recognition of foreign antigens by T lymphocytes. This chromosomal region contains a large number of genes whose products play particularly important roles in a number of cellular processes of the immune system;The genes of the MHC are prime candidates for genetic engineering of domestic species because of their importance in many biological phenomena, including disease resistance and reproduction. To analyze the molecular structure of the chicken MHC, cDNA clones coding for chicken MHC class II (B-L) [beta] chain molecules were ...


Pulsed-Field Gel Electrophoresis Studies Of Rhizobiaceae , Bruno Walther S. Sobral Jan 1989

Pulsed-Field Gel Electrophoresis Studies Of Rhizobiaceae , Bruno Walther S. Sobral

Retrospective Theses and Dissertations

The migration properties of circular, covalently closed (ccc) and linear DNAs were studied in pulsed-field gel electrophoresis as a model system for resolving large plasmids in the Rhizobiaceae. The effects of varying pulse time and agarose concentration on the electrophoretic mobility cccDNAs, ranging from 2 kilobase pairs (kb) to 16 kb, was investigated. We used both field inversion gel electrophoresis (FIGE) and electrophoresis in contour-clamped homogeneous electric fields (CHEF); both ccc and linear molecules had a minimum mobility as a function of pulse time in a CHEF apparatus. Linear and cccDNAs of the same size were affected differently by pulse ...


Spectral Hole Burning Studies Of Photosystem 1, J. Kevin Gillie Jan 1989

Spectral Hole Burning Studies Of Photosystem 1, J. Kevin Gillie

Retrospective Theses and Dissertations

Persistent spectral hole burning is applied to the reaction center, P700, and the light harvesting chlorophyll protein complexes of Photosystem I. A theory for solid state spectral hole burning is developed that is valid for arbitrarily strong linear electron-phonon coupling within the Condon approximation. Persistent photochemical hole burning of the reaction center P700, reveals that a broad (~300 cm[superscript] -1) hole can be burned into the adsorption profile. The hole profile and its maximum position and intensity dependence on burn wavelength are adequately fit by the electron-phonon coupling theory. The results indicate that the absorption and hole profile are ...


Development Of Molecular Genetic Approaches To Study Mycoplasma Pathogenesis , Gregory G. Mahairas Jan 1989

Development Of Molecular Genetic Approaches To Study Mycoplasma Pathogenesis , Gregory G. Mahairas

Retrospective Theses and Dissertations

Transposons Tn4001 and Tn916 have been introduced into M. pulmonis. Additionally, the antibiotic resistance genes of both transposable elements have been cloned and integrative plasmids constructed that carry chromosomal DNA as a region of homology. Transposons and integrative plasmids were used to study polyethylene glycol mediated transformation in M. pulmonis and the optimal transformation frequencies were obtained in a mixture containing 35.5% PEG, 10 ug plasmid DNA, 10 ug yeast tRNA and 1 x 10[superscript]8 cells. Transformation frequencies were enhanced four- to five-fold by preincubating cells at 0° C for 30 min. in CaCl[subscript]2 prior ...


Aspects Of Regulation Of Ketoglutarate Dehydrogenase Activity From Ribbed Mussel (Modiolus Demissus) Gills And Cauliflower (Brassica Oleracea) , George Antun Karam Jan 1989

Aspects Of Regulation Of Ketoglutarate Dehydrogenase Activity From Ribbed Mussel (Modiolus Demissus) Gills And Cauliflower (Brassica Oleracea) , George Antun Karam

Retrospective Theses and Dissertations

In ribbed bivalve mollusc gills, the enzyme ketoglutarate dehydrogenase is regulated by pH, ketoglutarate and adenine nucleotides but not by calcium ions. In cauliflower, the enzyme is regulated by variations in Ca[superscript] 2+, Mg[superscript] 2+, adenine nucleotides and ketoglutarate. In plants, the decrease in mitochondrial Ca[superscript] 2+ inhibits KGDH whereas the entry of Ca[superscript] 2+ reactivates the enzyme. No such regulation appears to exist with the ribbed mussel KGDH.


Mechanisms Of Protein S-Thiolation And Dethiolation , Eun-Mi Choi Park Jan 1989

Mechanisms Of Protein S-Thiolation And Dethiolation , Eun-Mi Choi Park

Retrospective Theses and Dissertations

Mechanisms of S-thiolation and dethiolation of creatine kinase and glycogen phosphorylase b were studied. S-thiolation of the two proteins was initiated by oxyradicals generated by xanthine oxidase in reaction mixtures containing reduced glutathione (GSH). Both proteins were extensively modified under the conditions in which the oxidation of glutathione was inadequate to cause S-thiolation by thiol-disulfide exchange. Creatine kinase was both S-thiolated and non-reducibly oxidized at low GSH concentration, but with adequate GSH, oxidation was prevented while S-thiolation was still active. S-thiolation of glycogen phosphorylase b was not significantly affected by GSH concentration and non-reducible oxidation was not observed. The results ...


Isolation Of Upstream Control Regions Of Genes Expressed At Different Times During Growth And Sporulation In Bacillus Thuringiensis , John Michael Hurley Jan 1989

Isolation Of Upstream Control Regions Of Genes Expressed At Different Times During Growth And Sporulation In Bacillus Thuringiensis , John Michael Hurley

Retrospective Theses and Dissertations

To investigate the mechanisms of gene expression in Bacillus thuringiensis subsp. kurstaki HD251, HindIII-digested total DNA was ligated into plasmid pKO1, which contains a promoterless galK gene. E. coli HB101 (GalK[superscript]-) transformant colonies resistant to ampicillin and red in color on MacConkey-galactose agar (indicating transformation to the GalK[superscript]+ phenotype) presumably contain B. thuringiensis DNA inserts in pKO1 that function as promoters in E. coli. To determine if such sequences control gene expression in B. thuringiensis, total RNA probes were prepared from cultures at specified times throughout growth and sporulation and used to screen plasmid DNA "dot-blots." Several plasmids ...


Analysis Of Mutator Activity In Embryogenic Callus Cultures And Regenerated Plants Of Zea Mays L. , Martha Graham James Jan 1989

Analysis Of Mutator Activity In Embryogenic Callus Cultures And Regenerated Plants Of Zea Mays L. , Martha Graham James

Retrospective Theses and Dissertations

Activity of the Mutator transposable element system in maize was assessed in tissue cultures and regenerated plants by Southern analysis of Mu-element modification status and genomic position. Examination of embryogenic callus cultures established from the F[subscript]1's of crosses between active Mutator stock and maize inbreds A188 and H99 determined that the in planta parameters for Mutator activity were maintained in an in vitro environment. Subclonal populations from callus lines were used to demonstrate that Mu elements from active Mutator lines can remain transpositionally active in tissue culture systems. Novel Mu-homologous restriction fragments occurred in 38% of the ...


Sequence Heterogeneity Of Bovine Mitochondrial Dna , Gary Leroy Lindberg Jan 1989

Sequence Heterogeneity Of Bovine Mitochondrial Dna , Gary Leroy Lindberg

Retrospective Theses and Dissertations

The displacement-loop (D-loop) region of bovine mitochondrial DNA (mtDNA) isolated from blood leukocytes was studied. A method was devised for the isolation of mtDNA from blood leukocytes based on detergent lysis of the plasma membrane and removal of cell nuclei by centrifugation. Nucleic acids extracted from the residual cytoplasmic fraction contained mtDNA in quantities sufficient for restriction enzyme analysis and for DNA cloning and sequencing;MtDNA was from a herd of Holstein cattle that was established 1968 from diverse genetic sources. Maternal lineages were traced by pedigree analysis to their earliest origins in the late 1800s. MtDNA was isolated from ...


Recognition Of Valine Transfer Rna By Valyl-Trna Synthetase From E Coli: 19f Nmr And Aminoacylation Studies Involving Wild Type And Mutant Forms Of 5-Fluorouracil-Substituted Trnaval, Wen-Chy Chu Jan 1989

Recognition Of Valine Transfer Rna By Valyl-Trna Synthetase From E Coli: 19f Nmr And Aminoacylation Studies Involving Wild Type And Mutant Forms Of 5-Fluorouracil-Substituted Trnaval, Wen-Chy Chu

Retrospective Theses and Dissertations

The structural basis for the recognition of valine transfer RNA (tRNA[superscript] Val) by valyl-tRNA synthetase (VRS) from E. coli has been investigated by [superscript]19F NMR spectroscopy, aminoacylation kinetics and the technique or site-directed mutagenesis. The accomplishments presented here entail (1) the development of protocols for the synthesis of wild type and mutant tRNA[superscript] Val having 5-fluorouracil in place of uracil, (2) the direct assignment of [superscript]19F NMR peaks to specific FUra residues in tRNA[superscript] Val, and (3) the role played by specific bases in the recognition of tRNA[superscript] Val by its cognate synthetase;For ...