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R J MacIntyre

Publications and source records attributed to R J MacIntyre.

At least 37 records · Page 2Linked to original sources
PubMed1983

The characterization of alpha-glycerophosphate dehydrogenase mutants in Drosophila melanogaster.

Thirty mutants of alpha-glycerophosphate dehydrogenase (alpha GPDH, EC 1.1.1.8) from Drosophila melanogaster were produced with the chemical mutagen ethyl methanesulfonate (EMS). These mutants and nine others previously obtained have been characterized with respect to level of enzymatic activity, viability, flight ability, and presence of cross-reacting material (CRM). The presence of alpha GPDH mRNA in several of the mutans has been tested by in vitro translation. There are strong correlations between the level of enzyme activity, viability and flight ability. Thirteen of the mutants are CRM- by solution immunoprecipitation experiments, but of these, only three are CRM- by a more sensitive 125I-protein A-based radioimmune gel assay. The viability of the three CRM- mutants suggests that the absence of alpha GPDH protein is not a lethal condition. The immunoprecipitated protein of the low activity mutant, alpha GpdhnGL3, has a smaller apparent molecular weight on polyacrylamide-SDS gels than does the protein from wild type. Criteria for the identification of nonsense mutations in Drosophila are discussed.

Animals↗
PubMed1978

Evolution of acid phosphatase-1 in the genus Drosophilia. Immunological studies.

The enzyme acid phosphatase-1 was partially purified from 10 Drosophila species. Four antisera were produced and the ten enzymes were reacted against each serum. The method used to quantitate the reactions involved the electrophoretic separation of antigen-antibody complexes from uncomplexed enzyme, followed by densitometry of the free enzyme. Immunological distances were used to obtain correlation coefficients for all pairwise combinations of the 10 species. From these correlation coefficients, a dendrogram was constructed which is very similar to one diagramming the presumed phylogenetic relationships of the ten species. In addition, the data indicate acid phosphatase-1 has evolved at different rates in different lineages within the genus. A preliminary estimate of the unit evolutionary period for this enzyme is 3.25 million years. The method of determining immunological distances which was used in this study is compared to the method of microcomplement fixation in the Discussion.

Acid Phosphatase↗
PubMed1978

Quantitative subunit hybridization of drosophila alpha-glycerophosphate dehydrogenase.

The dimeric enzyme, alpha-Glycerophosphate dehydrogenase, was purified from eight Drosophila species by the method of Collier et al. (1976). The enzymes were inactivated at high pH and the conditions sufficient for reactivation were established. Electrophoretic patterns of reactivated alpha-glycerophosphate dehydrogenases which were mixed following inactivation of two species' enzymes, demonstrate that high pH dissociates the enzyme into its constituent subunits and reactivation involves subunit reassociation. Twenty interspecific combinations of dissociated enzymes were allowed to reassociate, and the amounts of both heterospecific and homospecific enzyme activity and protein were determined by densitometry. In all 20 tests there were no differences between observed and expected heterospecific:homospecific enzyme ratios. These results are consistent with the very slow rate of evolution of this enzyme in the family Drosophilidae (Collier and MacIntyre, 1977).

Animals↗
PubMed1978

Theoretical considerations of the sensitivity of quantitative subunit hybridization.

The theoretical basis of the quantitative subunit hybridization technique and its ability to measure evolutionary amino acid substitutions is examined. Homospecific:heterospecific enzyme ratios found after subunit reassociation depend upon K1.2, the equilibrium constant for the dissociation of the heterospecific enzyme. It is shown that if this constant is near the geometric mean of the two homospecific enzyme dissociation constants, as it should be in enzymes whose subunits pair isologously, the quantitative subunit hybridization method will not detect most changes in the subunit contact regions of homologous proteins.

Biological Evolution↗
PubMed1978

Cytogenetic localization of the acid phosphatase-1 gene in Drosophila melanogaster.

A translocation in which a segment of chromosome 3 is inserted into the Y chromosome was found to contain the acid phosphatase-1 gene (Acph-1). In flies hyperploid for that gene, acid phosphatase-1 levels are proportional to the dose of the gene. The locus is placed within the salivary chromosome subdivisions 99D and 99E on the basis of its inclusion in the translocated segment and on the previous placement of the claret locus. Several chromosomal rearrangements involving heterochromatic breakpoints and euchromatic breakpoints adjacent to 99D-99E were tested for possible postiion-effect variegation of acid phosphatase-1. No decrease in the synthesis of the electorphoretic subunit encoded by the relocated gene was observed within any of the rearrangements.

Acid Phosphatase↗
PubMed1977

Microcomplement fixation studies on the evolution of alpha-glycerophosphate dehydrogenase within the genus Drosophila.

Antisera were prepared against purified alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) (alphaGPDH) from Drosophila melanogaster, D. virilis, and D. busckii. The immunological distances between the enzymes from the 3 species and those from 31 additional drosophilid species agree in general with the accepted phylogeny of the genus. These data permit an estimate that the subgenus Sophophora diverged 52 million years ago from the line leading to the subgenus Drosophila. The antiserum against melanogaster alphaGPDH was capable of distinguishing allelic variants of alphaGPDH. On the basis of presumed single amino acid substitutions, no drosophilid alphaGPDH tested differed from the melanogaster enzyme by more than eight or nine substitutions. The study was extended to include representatives of six other dipteran families. The immunological distances between alphaGPDH from Drosophila and alphaGPDH from these dipterans were reasonably consistent with a phylogeny of the order Diptera established by more conventional means. The unit evolutionary period of this enzyme was estimated to be 18 million years.

Animals↗
PubMed1976

Purification of alpha-glycerophosphate dehydrogenase from Drosophila melanogaster.

A simple procedure has been devised for the purification of alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) FROM Drosophila melanogaster. The method involves substrate elution of the enzyme from a carboxymethyl cellulose column, followed by salt elution from agarose-hexane-AMP and DEAE columns. The procedure requires only 3 days to complete, results in high yield, and preparations that appear homogeneous by several criteria. A subunit molecular weight of 31 700 was obtained by sodium dodecyl sulphate electrophoresis in 10% acrylamide gels. This value is half that published for the native enzyme, confirming the homodimeric structure of this enzyme suggested by genetic evidence.

Animals↗
PubMed1976

Ultrastructural histochemical localization of acid phosphatase in salivary glands of Drosophila melanogaster.

The ultrastructural histochemical localization of acid phosphatase in salivary glands of third instar larvae of Drosophila melanogaster has been studied. Using Gomori's lead phosphate method for acid phosphatase detection, the optimal incubation time in the reaction medium was determined to be 30 min. When glands having wild-type acid phosphatase activity are incubated for this time, deposition of the final reaction product is observed in essentially every lysosome and artifactual staining is minimal.

Acid Phosphatase↗