A ribonucleic acid-protein relationship inDrosophila nutrition

Increased internal and external bacterial load during Drosophila aging without life-span trade-off

The role of microbial load during aging of the adult fruit fly Drosophila melanogaster is incompletely understood. Here we show dramatic increases in aerobic and anaerobic bacterial load during aging, both inside the body and on the surface. Scanning electron microscopy and cell staining analyses of the surface of aged flies detected structures resembling abundant small bacteria and bacterial biofilms. Bacteria cultured from laboratory flies included aerobic species Acetobacter aceti, Acetobacter tropicalis, and Acetobacter pasteurianus and anaerobic species Lactobacillus plantarum and Lactobacillus sp. MR-2; Lactobacillus homohiochii, Lactobacillus fructivorans, and Lactobacillus brevis were identified by DNA sequencing. Reducing bacterial load and antimicrobial peptide gene expression by axenic culture or antibiotics had no effect on life span. We conclude that Drosophila can tolerate a significant bacterial load and mount a large innate immune response without a detectable trade-off with life span; furthermore, microbes do not seem to limit life span under optimized laboratory conditions.

Regulation of the oxidative NADP-enzyme tissue levels in Drosophila melanogaster. I. Modulation by dietary carbohydrate and lipid

Wild-type third instar larvae of Drosophilia melanogaster fed a casein-sucrose synthetic diet supplemented with phosphatidylcholine (4 mg/ml) possessed 33% more tissue lipid and a modified fatty acid profile compared to larvae fed a fat free-sucrose diet. The rates of lipid synthesis and pentose shunt activity were 2.1 and 2.2 times greater respectively in larvae fed the fat free-sucrose diet than in fat-sucrose fed animals. The tissue concentrations of acetyl-CoA and acyl-CoA were 80 and 61% higher respectively, CoA 49% lower, and the NADPH/NADP+ ratio greater in fat-sucrose fed larvae than in larvae fed a fat free-sucrose diet. Thus, larvae effectively utilized dietary lipid for lipid synthesis and as a supplementary energy source to carbohydrate.

Replacement of RNA in the diet of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) by purines, pyrimidines, and ribose

Oryzaephilus surinamensis (L.) survived in greater numbers when guanine and cytosine were added to a synthetic diet at a concentration of 0.4 mg/g each than when yeast RNA was included in the diet at 5.0 mg/g. They developed as quickly on this diet as when yeast RNA was added to the basic diet. This insect survived in greater numbers on the basic diet supplemented with D-ribose than on the unsupplemented basic diet and developed at the same rate on both. More adults emerged when D-ribose, guanine, and cytosine were added to the basic diet than when yeast RNA was added. However, fewer larvae pupated when these three substances were present than when only guanine and cytosine were added to the diet. In formulating a chemically defined diet for O. surinamensis, the results of this investigation showed that guanine and cytosine could replace yeast RNA and that D-ribose could be excluded from the diet without adverse effect.