In a sample of 79 genes with multiple introns, 33 showed significant heterogeneity in G+C content among introns of the same gene and significant positive correspondence between the intron and the third codon position G+C content within genes. These results are consistent with selection adding against preferred codons at the start of genes.

Pgd enzyme activity has been measured in D.melanogaster lines in which spontaneous mutations have accumulated over approximately 300 mutations.

Pgd is not correlated with geotaxis score in high and low hybrid derived lines.

The effects of a high sucrose diet on live weight, total protein, stored lipid and glycogen and crude activities of 12 enzymes involved in energy metabolism are quantified. The activities of many enzymes are reduced by the sucrose treatment.

Concentrations ranging from 2.5uM to 100uM adriamycin had no inhibitory effects on purified NADP enzymes.

Steroids slightly inhibit Zw activity but fail to inhibit Pgd activity.

At the DNA sequence level D.melanogaster populations from Zimbabwe are more than twice as variable as populations from U.S.A. Most variants are not shared between the two geographic regions and areas of low recombination rates have mutations that are nearly fixed.

Gramoxone has no mutagenic effect on the genetic background of Pgd.

Synonym "l(1)2Dc" on p544 and "l(1)2De" on p311.

In lines selected over 700 generations for high (negative) and low (positive) geotaxis, different alleles of Pgd found to have segregated out.

Characterisation of the cis-acting sequences necessary for expression of Pgd is performed using Ecol\lacZ reporter gene constructs. Results indicate that the large second intron is critical for Pgd expression in adults. Only 421bp of sequence are required to direct expression in imaginal discs. Sequence downstream from the transcription start point is necessary for expression in the larval fat body.

A saturation analysis of the 2D3--2F5 region detected the Pgd complementation group.

The effect of dietary sucrose and ethanol on Pgd activity in the third larval instar has been studied.

Structural gene for 6-phosphogluconate dehydrogenase (6PGD), the last enzyme in the oxidative part of the pentose phosphate shunt. The electrophoretic variants Pgd^A and Pgd^B have been described in Drosophila (Kazanian, Young and Childs, 1965; Young, 1966), Pgd^A migrating faster in starch gel than Pgd^B. Pgd^A/Pgd^B heterozygous females produce a hybrid band of intermediate mobility. The enzyme 6PGD is a dimer. Its molecular weight was reported by Kazanian (1966) to be about 79,000; Williamson et al. (1980), using 6PGD (purified) isolated from Pgd^A homozygotes, found its molecular weight to be 105,000, and that it contains a mixture of equal amounts of subunits having molecular weights of 55,000 and 53,000. Enzyme activity is highest in early third instar larvae and lowest in late third instar larvae and 3-day old pupae, with intermediate levels in 4-day old pupae, newly eclosed adults and 5-day old adults (Williamson, Krochko and Geer, 1980). The enzyme is found mainly in the fat body (Cochrane and Lucchesi, 1980). Males with one dose of Pgd⁺ and females with two doses have about the same amount of 6PGD, i.e. show dosage compensation for enzyme activity (Seecof et al., 1969; Gerasimova and Ananiev, 1972; Bowman and Simmons, 1973; Faizullin and Gvodev, 1973). Females heterozygous for a Pgd deficiency show a corresponding reduction in enzyme activity, while males and females with an extra dose of Pgd⁺ show increased enzyme activity. A number of lethal and semi-lethal Pgd mutants have been induced in Pgd^A or Pgd^B (Bewley and Lucchesi, 1975; Gvozdev et al., 1975; Hughes and Lucchesi, 1977; Gvozdev et al., 1978; Lucchesi, Hughes and Geer, 1979). The lethals (Pgdⁿ) show no enzyme activity unless covered by a Pgd⁺ duplication such as w⁺Y; the semi-lethals (Pgd^lo) show low enzyme activity and are completely lethal when heterozygous with Pgd lethals. Flies carrying null alleles for both G6PD, the first enzyme in the pentose phosphate shunt, and 6PGD, the last enzyme, are viable, presumably because the toxic 6-phosphogluconate is not produced (Lucchesi, Hughes and Geer, 1979). Pgdⁿ/Y males can be rescued by dietary supplements of fructose and linoleate that minimize 6-phosphogluconate production (Hughes and Lucchesi, 1978).