Slowing down the shuttle: C@S nanocomposites (see TEM images) based on mesoporous, hollow carbon capsules were generated by a template‐based approach. As the cathode material in a Li–S secondary battery, they display outstanding electrochemical features attributed to sequestration of elemental sulfur in the carbon capsules and to its favorable effect in limiting polysulfide shuttling as well as to enhanced electron transport from the sulfur.
Gene expression changes in response to aging, heat stress, hyperoxia, hydrogen peroxide, and ionizing radiation were compared using microarrays. A set of 18 genes were up-regulated across all conditions, indicating a general stress response shared with aging, including the heat shock protein (Hsp) genes Hsp70, Hsp83 and l(2)efl, the glutathione-S-transferase gene GstD2, and the mitochondrial unfolded protein response (mUPR) gene ref(2)P. Selected gene expression changes were confirmed using quantitative PCR, Northern analysis and GstD-GFP reporter constructs. Certain genes were altered in only a subset of the conditions, for example, up-regulation of numerous developmental pathway and signaling genes in response to hydrogen peroxide. While aging shared features with each stress, aging was more similar to the stresses most associated with oxidative stress (hyperoxia, hydrogen peroxide, ionizing radiation) than to heat stress. Aging is associated with down-regulation of numerous mitochondrial genes, including electron-transport-chain (ETC) genes and mitochondrial metabolism genes, and a sub-set of these changes was also observed upon hydrogen peroxide stress and ionizing radiation stress. Aging shared the largest number of gene expression changes with hyperoxia. The extensive down-regulation of mitochondrial and ETC genes during aging is consistent with an aging-associated failure in mitochondrial maintenance, which may underlie the oxidative stress-like and proteotoxic stress-like responses observed during aging.
Truncated
and mutant forms ofp53 affect life span in Drosophila,
nematodes and mice, however the role of wild-type p53 in aging
remains unclear. Here conditional over-expression of both wild-type and
mutant p53 transgenes indicated that, in adult flies, p53
limits life span in females but favors life span in males. In contrast,
during larval development, moderate over-expression of p53 produced
both male and female adults with increased life span. Mutations of the
endogenous p53 gene also had sex-specific effects on life span under
control and stress conditions: null mutation of p53 increased life
span in females, and had smaller, more variable effects in males. These
developmental stage-specific and sex-specific effects of p53 on
adult life span are consistent with a sexual antagonistic pleiotropy model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.