Abstract:
:We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols greater than bilirubin greater than urate greater than alpha-tocopherol and that detectable lipid peroxidation starts only after ascorbate has been consumed completely. In this paper, we show that it is indeed ascorbate that completely protects plasma lipids against detectable peroxidative damage induced by aqueous peroxyl radicals and that ascorbate is the only plasma antioxidant that can do so. Plasma devoid of ascorbate, but no other endogenous antioxidant, is extremely vulnerable to oxidant stress and susceptible to peroxidative damage to lipids. The plasma proteins' thiols, although they become oxidized immediately upon exposure to aqueous peroxyl radicals, are inefficient radical scavengers and appear to be consumed mainly by autoxidation. Our data demonstrate that ascorbate is the most effective aqueous-phase antioxidant in human blood plasma and suggest that in humans ascorbate is a physiological antioxidant of major importance for protection against diseases and degenerative processes caused by oxidant stress.
journal_name
Proc Natl Acad Sci U S Aauthors
Frei B,England L,Ames BNdoi
10.1073/pnas.86.16.6377subject
Has Abstractpub_date
1989-08-01 00:00:00pages
6377-81issue
16eissn
0027-8424issn
1091-6490journal_volume
86pub_type
杂志文章abstract::Broken-cell preparations of Salmonella typhimurium rapidly incorporated 75Se from 75SeO3(2-) into tRNA by an ATP-dependent process. Selenium incorporation in the presence of 50 microM 75SeO3(2-) (0.8-1 pmol per A260 unit) was enhanced by the selenocysteine precursor, O-acetyl-L-serine (to 3.7 pmol per A260 unit). This...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.87.16.6341
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abstract::The method of evolutionary stable strategies (ESS), in its current form, is confronted with a difficulty when it tries to explain how some social behaviors initiate their evolution. We show that this difficulty may be removed by changing the assumption made tacitly in game theory (and in ESS) of randomness of meetings...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1971-07-01 00:00:00
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更新日期:2020-04-07 00:00:00
abstract::Aryloxyphenoxypropionates, inhibitors of the plastid acetyl-CoA carboxylase (ACC) of grasses, also inhibit Toxoplasma gondii ACC. Clodinafop, the most effective of the herbicides tested, inhibits growth of T. gondii in human fibroblasts by 70% at 10 microM in 2 days and effectively eliminates the parasite in 2-4 days ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::DNA was extracted from the remains of 35 ground sloths from various parts of North and South America. Two specimens of Mylodon darwinii, a species that went extinct at the end of the last glaciation, yielded amplifiable DNA. However, of the total DNA extracted, only approximately 1/1000 originated from the sloth, wher...
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2012-11-20 00:00:00
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更新日期:2011-02-01 00:00:00
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更新日期:2003-08-05 00:00:00
abstract::The 24-hr intracarotid infusion of plasma-treated glycyl-L-glutamine (3 microM) produced significant enhancement of the monomeric G1 and tetrameric G4 forms of acetylcholinesterase of the cat superior cervical ganglion 48 hr after denervation, in comparison with denervated, noninfused controls. No significant effect o...
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pub_type: 杂志文章
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更新日期:1988-08-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2006-04-18 00:00:00
abstract::The peptide chain release factor 2 (RF2) gene, prfB, was cloned from Salmonella typhimurium by DNA hybridization using the Escherichia coli prfB probe. The nucleotide and amino acid sequences of prfB are 87.0% and 95.6% homologous between E. coli and S. typhimurium, respectively, including an in-frame premature UGA st...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0701331104
更新日期:2007-03-27 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2019-03-19 00:00:00
abstract::The interplay of human actions and natural processes over varied spatial and temporal scales can result in abrupt transitions between contrasting land surface states. Understanding these transitions is a key goal of sustainability science because they can represent abrupt losses of natural capital. This paper recogniz...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2013-04-09 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1982-06-01 00:00:00
abstract::Thrombin contains electropositive patches at opposite poles of the molecule which represent potential exosites for the binding of macromolecular ligands. The function of anion-binding exosite I, the fibrin(ogen) recognition site, has been well described. Anion-binding exosite II, located near the carboxyl terminus of ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.12.5518
更新日期:1994-06-07 00:00:00
abstract::Streptococcus groups A and B cause serious infections, including early onset sepsis and meningitis in newborns. Rib domain-containing surface proteins are found associated with invasive strains and elicit protective immunity in animal models. Yet, despite their apparent importance in infection, the structure of the Ri...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1911776116
更新日期:2019-12-09 00:00:00
abstract::Na(+)-channel inactivation is proposed to occur by binding of an intracellular inactivation gate to a hydrophobic inactivation gate receptor in the intracellular mouth of the pore. Amino acid residues in transmembrane segment S6 of domain IV (IVS6) that are critical for fast inactivation were identified by alanine-sca...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.25.12346
更新日期:1994-12-06 00:00:00
abstract::Misfolded proteins are eliminated from the endoplasmic reticulum (ER) by retrotranslocation into the cytosol, a pathway hijacked by certain viruses to destroy MHC class I heavy chains. The translocation of polypeptides across the ER membrane requires their polyubiquitination and subsequent extraction from the membrane...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2005-10-04 00:00:00
abstract::A mutation that confers resistance to the drug paromomycin is shown to be in the structural gene that codes for the ribosomal RNA in Tetrahymena. This observation was made by exploiting a variant of the ribosomal DNA that distorts amplification of this locus when a new somatic nucleus develops during conjugation. Beca...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1985-05-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1996-08-06 00:00:00
abstract::People who are more avoidant of pathogens are more politically conservative, as are nations with greater parasite stress. In the current research, we test two prominent hypotheses that have been proposed as explanations for these relationships. The first, which is an intragroup account, holds that these relationships ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,多中心研究
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更新日期:2016-11-01 00:00:00
abstract::Porphyromonas gingivalis is the major causative agent of periodontitis, and it may also be involved in the development of systemic diseases (atherosclerosis, rheumatoid arthritis). P. gingivalis is found on and within oral and gingival epithelial cells following binding to surface components of host cells, which serve...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2014-04-08 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0407796102
更新日期:2005-01-25 00:00:00