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Biology Faculty Articles

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Articles 181 - 186 of 186

Full-Text Articles in Genetics and Genomics

Analysis Of Multiple Isoenzyme Expression Among Twenty-Two Species Of Mycoplasma And Acholeplasma, Stephen J. O'Brien, Janice M. Simonson, Marion W. Grabowski, Michael F. Barile Apr 1981

Analysis Of Multiple Isoenzyme Expression Among Twenty-Two Species Of Mycoplasma And Acholeplasma, Stephen J. O'Brien, Janice M. Simonson, Marion W. Grabowski, Michael F. Barile

Biology Faculty Articles

Crude extracts of triple-cloned, purified cultures of 22 species of Mycoplasma and Acholeplasma were examined for expression of 21 isozyme systems routinely used to type mammalian cells. Nine previously described enzymes (purine nucleoside phosphorylase, adenylate kinase, dipeptidase, esterase, glyceraldehyde-3-phosphate dehydrogenase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and superoxide dismutase) and three enzymes not previously reported in mycoplasma (triose phosphate isomerase, inorganic pyrophosphatase, and acid phosphatase) were detected in some or all of the species examined. These findings provide new information on the enzymatic expressions of these organisms. Three of the isozyme systems (superoxide dismutase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) …


Bvr-1, A Restriction Locus Of A Type C Rna Virus In The Feline Cellular Genome: Pleiotropic Restriction Of Endogenous Balb Virus In Cat X Mouse Somatic Cell Hybrids, Stephen J. O'Brien, Janice M. Simonson Jan 1978

Bvr-1, A Restriction Locus Of A Type C Rna Virus In The Feline Cellular Genome: Pleiotropic Restriction Of Endogenous Balb Virus In Cat X Mouse Somatic Cell Hybrids, Stephen J. O'Brien, Janice M. Simonson

Biology Faculty Articles

Bvr-1 is a dominant X-linked feline gene which restricts the replication of B-tropic murineleukemia virus (B-MuLV) in somatic cell hybrids between murine BALB/c-RAG cells and FL-74 feline cells. Since the hybrids were originally derived by the hypoxanthine aminopterin thymidine selection scheme, counter selection experiments on 6-thioguanine result in preferential survival of hybrid cells which have spontaneously lost the feline X-chromosome on which is located the structural gene for hypoxanthine guanine phosphoribosyl transferase (IMP: pyrophosphate phosphoribosyl transferase, E.C. 2.4.2.8) and Bvr-1. Back selected Bvr-1- cells express high parental levels of B-MuLV. Bvr-1- effectively restricts the IdU-mediated induction of …


Bvr-1, A Restriction Locus Of A Type C Rna Virus In The Feline Cellular Genome: Identification, Location, And Phenotypic Characterization In Cat X Mouse Somatic Cell Hybrids, Stephen J. O'Brien Dec 1976

Bvr-1, A Restriction Locus Of A Type C Rna Virus In The Feline Cellular Genome: Identification, Location, And Phenotypic Characterization In Cat X Mouse Somatic Cell Hybrids, Stephen J. O'Brien

Biology Faculty Articles

Somatic cell hybrids were constructed between BALB/c-RAG mouse cells and feline lymphoma cells by the hypoxanthine-aminopterin-thymidine selection scheme. RAG cells spontaneously produce an endogenous B-tropic type C virus. Cat-mouse hybrids preferentially segregate feline chromosomes and retain murine chromosomes,demonstrable by karyotypic and isozyme analyses. Despite the presence of the complete mouse genome, including the viral genome, virus production was diminished to 1-5% of the levels observed in RAG parents based upon particle-associated RNA-dependent DNA polymerase (reverse transcriptase) activity in the culture fluid. Thirty-seven hybrids made on four different occasions had suppressed virus levels, and no hybrids expressed parental virus levels. Reverse …


The Α-Glycerophosphate Cycle In Drosophila Melanogaster Iv. Metabolic, Ultrastructural, And Adaptive Consequences Of Αgpdh-1 "Null" Mutations, Stephen J. O'Brien, Yoshio Shimada Dec 1974

The Α-Glycerophosphate Cycle In Drosophila Melanogaster Iv. Metabolic, Ultrastructural, And Adaptive Consequences Of Αgpdh-1 "Null" Mutations, Stephen J. O'Brien, Yoshio Shimada

Biology Faculty Articles

"Null" mutations previously isolated at the αGpdh-1 locus of Drosophila melanogaster, because of disruption of the energy-producing α-glycerophosphate cycle, severely restrict the flight ability and relative viability of affected individuals. Two "null" alleles, αGpdh-1BO-1-4, and αGpdh-1BO-1-5, when made hemizygous with a deficiency of the αGpdh-1 locus,Df(2L)GdhA, were rendered homozygous by recombination with and selective elimination of the Df(2L)GdhA chromosome. After over 25 generations, a homozygous αGpdh-1BO-1-4stock regained the ability to fly despite the continued absence of …


The Α-Glycerophosphate Cycle In Drosophila Melanogaster. Iii. Relative Viability Of "Null" Mutants At The Α-Glycerophosphate Dehydrogenase-1 Locus, Stephen J. O'Brien, Bruce Wallace, Ross J. Macintyre Nov 1972

The Α-Glycerophosphate Cycle In Drosophila Melanogaster. Iii. Relative Viability Of "Null" Mutants At The Α-Glycerophosphate Dehydrogenase-1 Locus, Stephen J. O'Brien, Bruce Wallace, Ross J. Macintyre

Biology Faculty Articles

No abstract provided.


An Analysis Of Gene-Enzyme Variability In Natural Populations Of Drosophila Melanogaster And D. Simulans, Stephen J. O'Brien, Ross J. Macintyre Mar 1969

An Analysis Of Gene-Enzyme Variability In Natural Populations Of Drosophila Melanogaster And D. Simulans, Stephen J. O'Brien, Ross J. Macintyre

Biology Faculty Articles

Nine populations of D. melanogaster and two populations of D. simulans were analyzed for polymorphism in 10 gene-enzyme systems by the technique of gel electrophoresis. In the eight natural populations of D. melanogaster, an average of 54% of the enzymes were polymorphic, and the average heterozygosity was 22.7%. An experimental population of D. melanogaster, which has been maintained in a laboratory cage for 20 years, showed levels of polymorphism equivalent to those of natural populations. The D. simulans populations had much less variability. The possible factors involved in maintaining these polymorphisms are discussed.