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Dietary restriction by growth in axenic medium induces discrete changes in the transcriptional output of genes involved in energy metabolism in Caenorhabditis elegans
Author(s) -
Castelein Natascha,
Hoogewijs David,
De Vreese Annemie,
Braeckman Bart P.,
Vanfleteren Jacques R.
Publication year - 2008
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.200800003
Subject(s) - caenorhabditis elegans , biology , axenic , phosphoenolpyruvate carboxykinase , gluconeogenesis , biochemistry , glyoxylate cycle , metabolic pathway , isocitrate lyase , microbiology and biotechnology , metabolism , gene , genetics , bacteria
Dietary restriction increases life span in a wide range of species, including the nematode worm Caenorhabditis elegans. The mechanism by which it does so remains largely unknown, although it is commonly thought that a reduction of reactive oxygen species (ROS) plays a pivotal role. More specifically, for C. elegans , it has been proposed that food restriction reduces energy expenditure, possibly in conjunction with an anaerobic shift in energy production, with consequent reduction in the formation of ROS. We have measured differential transcript abundance of 49 genes known to play roles in energy metabolism in axenic culture medium, which causes a nutritional deficit and leads to a substantial increase of life span. We found no evidence for a reduction in metabolic rate or a shift to anaerobic metabolism in axenic culture. Major changes induced by growth in axenic medium include down‐regulation of lipid degradation and up‐regulation of glyoxylate cycle activity glyceroneogenesis and, possibly, gluconeogenesis. The activities determined in worm extracts for pyruvate kinase, phosphoenolpyruvate carboxykinase and isocitrate lyase followed a similar trend. We conclude that growth in axenic culture is marked by a general up‐regulation of replenishing pathways.