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S M Sternick

Publications and source records attributed to S M Sternick.

2 recordsLinked to original sources

Ascorbic acid in Drosophila and changes during aging.

The ascorbic acid content of Drosophila melanogaster was found to be high in the absence of a dietary source. The amount of ascorbic acid per fly declined with aging in both the Oregon R and Swedish C strains. The median life span at 25 degrees C was 45 days for Swedish C and 59 days for Oregon R. The amount of ascorbic acid in Swedish C flies (0.078 micrograms/fly) was higher than that for Oregon R (0.058 micrograms/fly) for newly emerged flies but the rate of decline with aging was greater for Swedish C than Oregon R. The decline in ascorbic acid content with aging was 70.4% for Swedish C versus 19.9% for Oregon R. A brief cold shock was found to significantly increase the amount of ascorbic acid in Oregon R flies. Feeding the precursor of ascorbic acid synthesis, L-gulonolactone, did not improve the life span. Life-time feeding of ascorbic acid did not improve the life span of either Swedish C or Oregon R flies.

Aging

Changes in boron concentration during development and ageing of Drosophila and effect of dietary boron on life span.

Total boron concentrations in Drosophila changed during development and ageing. The highest concentration of boron was found during the egg stage followed by a decline during the larval stages. Newly emerged flies contained 35.5 ppm boron. During the adult stage the boron concentration increased by 52% by 9 weeks of age. Adding excess dietary boron during the adult stage decreased the median life span by 69% at 0.01 M sodium borate and by 21% at 0.001 M sodium borate. Lower concentrations gave small but significant increases in life span. Supplementing a very low boron diet with 0.00025 M sodium borate improved life span by 9.5%. The boron contents of young and old mouse tissues were similar to those of Drosophila and human samples. We conclude that moderate levels of dietary boron may have a general protective effect in biological systems. The mechanism of this effect at present remains unknown.

Aging