Linked Life Data

9862235

Source:http://linkedlifedata.com/resource/pubmed/id/9862235

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-3-22
pubmed:abstractText
Calorie restriction (R) is the only known method to delay the aging process and extend mean and maximal lifespan in rodents. R has been shown to delay the age-related accumulation of damaged proteins and to protect organisms from various stresses which can produce damaged proteins. Such stresses include irradiation, heat shock, and oxidative stress. The ubiquitin- and ATP-dependent proteolytic pathway (UPP) has been associated with the degradation of abnormal and/or damaged proteins. We examined the effect of diet and oxidative stress on activities of the UPP in supernatants from livers taken from 23-month-old Emory mice which had been exposed to an in-vivo injection of paraquat. Paraquat induces oxidative stress by generating superoxide radicals. In livers from non-stressed animals, steady-state levels of endogenous ubiquitin conjugates, de novo conjugate formation, and E1 and E2 activities were significantly lower in R animals than in control (C) animals. However, after exposure to paraquat, levels of endogenous ubiquitin conjugates were significantly higher in R versus C animals, and de novo conjugate formation and E1 and E2 activities in R animals rose to levels which were indistinguishable from levels of these activities noted in C animals. R was associated with an increased ability to degrade beta-lactoglobulin by the UPP after an oxidative stress was imposed. Ability to degrade beta-lactoglobulin by the C or R livers in non-stressed animals was not significantly different. Taken together, these data indicate that oxidative stress in R animals is associated with enhanced levels of ubiquitin conjugates and that this enhancement may be due to an increase in UPP activity. These data also indicate that the ability to form ubiquitin conjugates and the UPP system does not change with oxidative stress in C animals. The latter is consistent with prior reports that suggests that older C animals may already be in a state of enhanced oxidative stress and that activities of the UPP provide a sensitive indicator of levels of cellular redox status.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0047-6374
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
105
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
273-90
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Calorie restriction, stress and the ubiquitin-dependent pathway in mouse livers.
pubmed:affiliation
Laboratory for Nutrition and Vision Research, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.