title: Influence of diet on chromatin organization in insect mid-gut cells, and its implications for the understanding of aging in this model system.
abstract: Female Sarcophaga bullata were fed on three different dietary combinations: liver/water; sugar/water; and sugar/liver/water. These diets resulted in different survival patterns for the insect, with the longest lifespans being expressed on the last treatment. The Feulgen-DNA values for mid-gut cell nuclei were determined using a scanning and integrating microdensitometer. The cell nuclei of the mid-gut reacted to the presence of nutrients by an increase in the extinction values for Feulgen-DNA when compared to the unfed state. There were also significant differences between the various treatments in the extent of the activation shown by the mid-gut cells. The dietary regimes resulting in the longest lifespan showed a complete and uniform activation of the mid-gut epithelium, whereas other treatments did not. These observations suggest that changes in the chromatin organization occur with diet, and that maximum Feulgen-DNA extinctions occur (i.e. chromatin uncoiled and supporting transcription) on the sugar/liver/water diet. Nuclei showing maximum extinctions do not show an age-related change between 3 and 12 days of life. However, if the nuclear activation is partial, or incomplete, then age-related reversals in chromatin condensation take place.
mesh_terms: D000375:Aging; D000818:Animals; D002241:Carbohydrates / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D002843:Chromatin / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004175:Diptera / Q000502:physiology*; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D007422:Intestines / Q000166:cytology; D008017:Life Expectancy; D008099:Liver; D008954:Models, Biological
chemical_list: D002241:Carbohydrates; D002843:Chromatin; D004247:DNA