Age- and calorie-independent life span extension from dietary restriction by bacterial deprivation in Caenorhabditis elegans.
BACKGROUND
Dietary restriction (DR) increases life span and delays age-associated disease in many organisms. The mechanism by which DR enhances longevity is not well understood.


RESULTS
Using bacterial food deprivation as a means of DR in C. elegans, we show that transient DR confers long-term benefits including stress resistance and increased longevity. Consistent with studies in the fruit fly and in mice, we demonstrate that DR also enhances survival when initiated late in life. DR by bacterial food deprivation significantly increases life span in worms when initiated as late as 24 days of adulthood, an age at which greater than 50% of the cohort have died. These survival benefits are, at least partially, independent of food consumption, as control fed animals are no longer consuming bacterial food at this advanced age. Animals separated from the bacterial lawn by a barrier of solid agar have a life span intermediate between control fed and food restricted animals. Thus, we find that life span extension from bacterial deprivation can be partially suppressed by a diffusible component of the bacterial food source, suggesting a calorie-independent mechanism for life span extension by dietary restriction.


CONCLUSIONS
Based on these findings, we propose that dietary restriction by bacterial deprivation increases longevity in C. elegans by a combination of reduced food consumption and decreased food sensing.
Smith
Erica D
ED
Department of Pathology, University of Washington, Seattle, WA 98195, USA. ericas4@u.washington.edu
Kaeberlein
Tammi L
TL
Lydum
Brynn T
BT
Sager
Jennifer
J
Welton
K Linnea
KL
Kennedy
Brian K
BK
Kaeberlein
Matt
M
D000818:Animals; D001419:Bacteria; D017173:Caenorhabditis elegans / Q000502:physiology*; D031204:Caloric Restriction; D017077:Culture Media, Conditioned; D005508:Food Deprivation / Q000502:physiology; D005516:Food Microbiology; D008136:Longevity / Q000235:genetics / Q000502:physiology*
D017077:Culture Media, Conditioned