Fermented brown
sugar residue (FBSR) is generated in the course of purifying biomass ethanol
from the yeast fermentation products of brown sugar. It contains abundant
nutrition and is used in various industrial applications including as
fertilizer and feed. Meanwhile, brown sugar has attracted attention as a health
food and is thought to prevent cardiovascular diseases, hypertension, and brain
stem diseases. Furthermore, polyphenol, contained in brown sugar, reduces
oxidative stress and inhibits glucose absorption.
DAF-16 is a
transcription factor regulated downstream of the insulin signaling pathway and
is one of the main factors contributing to aging and lifespan in C. elegans. Therefore, to determine the
precise roles of the DAF-16 transcription factor in stress tolerance and life
span, it is necessary to elucidate the signaling pathways involved in DAF-16
activation.
This study was
designed to elucidate the molecular mechanisms controlling the physiological
stress tolerance, motility, and lifespan responses to FBSR by using Caenorhabditis
elegans, a free-living (not parasitic), transparent
nematode. In this study, fermented brown sugar residue was divided
into two layers: supernatant and precipitate fractions, and each was given to
nematodes. Synchronization was performed to unify the C. elegans stage of growth.
Analysis of
motility and survival rate under thermal stress revealed reduced mobility and
increased survival rate following treatment with fermented brown sugar residue.
The survival rate of nematodes under 1% H2O2 was
markedly increased by the residue and mitochondrial membrane depolarization was
induced and mitochondrial radical oxygen species levels increased. Furthermore,
aging dependent reduction of motility was suppressed, and the average life span
of nematodes was extended by treatment with fermented brown sugar residue.
Moreover, the effects of fermented brown sugar residue on stress tolerance,
lifespan elongation, and decreased aging dependent momentum reduction were lost
in the DAF-16 mutant.
Taken together, the
results show that the various physiological actions of fermented brown sugar
residue, including stress tolerance and lifespan extension, occur via DAF-16.
Article by Takumi
Satoh and Kazuichi Sakamoto, from University of Tsukuba, Tsukuba, Japan.
Full access: http://mrw.so/1naVdO
Image by Marco Verch, from Flickr-cc.
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