Abstract:
:The putative oxidation of hydroethidine (HE) has become a widely used fluorescent assay for the detection of superoxide in cultured cells. By covalently joining HE to a hexyl triphenylphosphonium cation (Mito-HE), the HE moiety can be targeted to mitochondria. However, the specificity of HE and Mito-HE for superoxide in vivo is limited by autooxidation as well as by nonsuperoxide-dependent cellular processes that can oxidize HE probes to ethidium (Etd). Recently, superoxide was shown to react with HE to generate 2-hydroxyethidium [Zhao, H., Kalivendi, S., Zhang, H., Joseph, J., Nithipatikom, K., Vasquez-Vivar, J. & Kalyanaraman, B. (2003) Free Radic. Biol. Med. 34, 1359-1368]. However, 2-hydroxyethidium is difficult to distinguish from Etd by conventional fluorescence techniques exciting at 510 nm. While investigating the oxidation of Mito-HE by superoxide, we found that the superoxide product of both HE and Mito-HE could be selectively excited at 396 nm with minimal interference from other nonspecific oxidation products. The oxidation of Mito-HE monitored at 396 nm by antimycin-stimulated mitochondria was 30% slower than at 510 nm, indicating that superoxide production may be overestimated at 510 nm by even a traditional superoxide-stimulating mitochondrial inhibitor. The rate-limiting step for oxidation by superoxide was 4x10(6) M-1.s-1, which is proposed to involve the formation of a radical from Mito-HE. The rapid reaction with a second superoxide anion through radical-radical coupling may explain how Mito-HE and HE can compete for superoxide in vivo with intracellular superoxide dismutases. Monitoring oxidation at both 396 and 510 nm of excitation wavelengths can facilitate the more selective detection of superoxide in vivo.
journal_name
Proc Natl Acad Sci U S Aauthors
Robinson KM,Janes MS,Pehar M,Monette JS,Ross MF,Hagen TM,Murphy MP,Beckman JSdoi
10.1073/pnas.0601945103subject
Has Abstractpub_date
2006-10-10 00:00:00pages
15038-43issue
41eissn
0027-8424issn
1091-6490pii
0601945103journal_volume
103pub_type
杂志文章abstract::We have previously described an antigen-specific I-Ad-restricted T-cell hybridoma, A1.1, that constitutively releases an antigen-specific immunoregulatory activity into supernatants. Using retrovirally mediated gene transfer, we have found that transfer of the T-cell receptor alpha chain (TCR alpha) gene from A1.1 to ...
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.88.19.8475
更新日期:1991-10-01 00:00:00
abstract::Steroidogenic acute regulatory protein (StAR) appears to mediate the rapid increase in pregnenolone synthesis stimulated by tropic hormones. cDNAs encoding StAR were isolated from a human adrenal cortex library. Human StAR, coexpressed in COS-1 cells with cytochrome P450scc and adrenodoxin, increased pregnenolone synt...
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.92.11.4778
更新日期:1995-05-23 00:00:00
abstract::Chemoresistance of cisplatin therapy is related to extensive repair of cisplatin-modified DNA in the nucleus by the nucleotide excision repair (NER). Delivering cisplatin to the mitochondria to attack mitochondrial genome lacking NER machinery can lead to a rationally designed therapy for metastatic, chemoresistant ca...
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.1405244111
更新日期:2014-07-22 00:00:00
abstract::The spatial structure of genetic diversity underlying social variation is a critical determinant of how cooperation and conflict evolve. Here we investigated whether natural social groups of the cooperative soil bacterium Myxococcus xanthus harbor internal genetic and phenotypic variation and thus the potential for so...
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.1100307108
更新日期:2011-06-28 00:00:00
abstract::Distributions of sulfur isotopes in geological samples would provide a record of atmospheric composition if the mechanism producing the isotope effects could be described quantitatively. We determined the UV absorption spectra of 32SO2, 33SO2, and 34SO2 and use them to interpret the geological record. The calculated i...
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.0903518106
更新日期:2009-09-01 00:00:00
abstract::Monoclonal antibodies against the porcine 1,25-dihydroxyvitamin D3 receptor were immobilized on Sepharose CL-4B and used to obtain a highly purified 1,25-dihydroxyvitamin D3 receptor fraction with a 45% recovery of the 1,25-dihydroxyvitamin D3 binding capacity. The porcine receptor was purified to homogeneity by prepa...
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.85.8.2454
更新日期:1988-04-01 00:00:00
abstract::Control over the fluorescence of supramolecular assemblies is crucial for the development of chemosensors and light-emitting materials. Consequently, the postsynthetic modification of supramolecular structures via host-guest interactions has emerged as an efficient strategy in recent years that allows the facile tunin...
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.1702510114
更新日期:2017-03-21 00:00:00
abstract::The vacuolar (H(+))-ATPases (V-ATPases) are ATP-dependent proton pumps that acidify intracellular compartments and pump protons across specialized plasma membranes. Proton translocation occurs through the integral V(0) domain, which contains five different subunits (a, d, c, c', and c"). Proton transport is critically...
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.221291798
更新日期:2001-10-23 00:00:00
abstract::In Caenorhabditis elegans, pre-mRNA for the essential splicing factor U2AF65 sometimes is spliced to produce an RNA that includes an extra 216-bp internal exon, exon 3. Inclusion of exon 3 inserts an in-frame stop codon, yet this RNA is not subject to SMG-mediated RNA surveillance. To test whether exon 3 causes RNA to...
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.96.7.3813
更新日期:1999-03-30 00:00:00
abstract::Inferring evolutionary relationships among highly divergent protein sequences is a daunting task. In particular, when pairwise sequence alignments between protein sequences fall <25% identity, the phylogenetic relationships among sequences cannot be estimated with statistical certainty. Here, we show that phylogenetic...
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.0803860105
更新日期:2008-09-09 00:00:00
abstract::A coenzyme B12-dependent ribonucleotide reductase was purified from the archaebacterium Thermoplasma acidophila and partially sequenced. Using probes derived from the sequence, the corresponding gene was cloned, completely sequenced, and expressed in Escherichia coli. The deduced amino acid sequence shows that the cat...
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.94.1.53
更新日期:1997-01-07 00:00:00
abstract::In the realm of protein-protein interactions, the assembly process of homooligomers plays a fundamental role because the majority of proteins fall into this category. A comprehensive understanding of this multistep process requires the characterization of the driving molecular interactions and the transient intermedia...
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.1320077110
更新日期:2013-12-03 00:00:00
abstract::8-Oxoguanine (8OG) is efficiently bypassed by RNA polymerases in vitro and in bacterial cells in vivo, leading to mutant transcripts by directing incorporation of an incorrect nucleotide during transcription. Such transcriptional mutagenesis (TM) may produce a pool of mutant proteins. In contrast, transcription-couple...
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.0806464105
更新日期:2008-12-02 00:00:00
abstract::Promoters whose temporal activity can be directly manipulated in transgenic animals provide a tool for the study of gene functions in vivo. We have evaluated a tetracycline-responsive binary system for its ability to temporally control gene expression in transgenic mice. In this system, a tetracycline-controlled trans...
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.91.20.9302
更新日期:1994-09-27 00:00:00
abstract::Glucagon-like peptide-1 (GLP-1), released from gut endocrine L cells in response to glucose, regulates appetite, insulin secretion, and gut motility. How glucose given orally, but not systemically, induces GLP-1 secretion is unknown. We show that human duodenal L cells express sweet taste receptors, the taste G protei...
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.0706890104
更新日期:2007-09-18 00:00:00
abstract::Hepatitis C virus (HCV) is a major cause of liver disease, affecting over 2% of the world's population. The HCV envelope glycoproteins E1 and E2 mediate viral entry, with E2 being the main target of neutralizing antibody responses. Structural investigations of E2 have produced templates for vaccine design, including t...
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.1609780113
更新日期:2016-11-08 00:00:00
abstract::The prion protein (PrP) is a scrapie-associated fibril protein that accumulates in the brains of hamsters and mice infected with the scrapie agent, and also in the brains of persons affected with kuru or Creutzfeldt-Jakob disease. It has been previously proposed that PrP could be either the primary transmissible agent...
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.83.17.6372
更新日期:1986-09-01 00:00:00
abstract::A synchronized heart beat is controlled by pacemaking impulses conducted through Purkinje fibers. In chicks, these impulse-conducting cells are recruited during embryogenesis from myocytes in direct association with developing coronary arteries. In culture, the vascular cytokine endothelin converts embryonic myocytes ...
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.96.23.13214
更新日期:1999-11-09 00:00:00
abstract::One of the serious limitations of tokamaks as reactors is the occurrence of disruptions. Stellarators designed by advanced computational methods provide an attractive alternative for a major experiment in magnetic fusion research. Configurations with approximate two-dimensional magnetic symmetry have been found with h...
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.97.3.972
更新日期:2000-02-01 00:00:00
abstract::For a series of different proteins, including a structural protein, enzyme, inhibitor, protein marker, and a charge-transfer system, we have quantified the higher affinity of Na+ over K+ to the protein surface by means of molecular dynamics simulations and conductivity measurements. Both approaches show that sodium bi...
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.0606959103
更新日期:2006-10-17 00:00:00
abstract::Prion disease is characterized by the alpha-->beta structural conversion of the cellular prion protein (PrP(C)) into the misfolded and aggregated "scrapie" (PrP(Sc)) isoform. It has been speculated that methionine (Met) oxidation in PrP(C) may have a special role in this process, but has not been detailed and assigned...
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.0902688106
更新日期:2009-05-12 00:00:00
abstract::Genetic variation in the peptide-binding groove of the highly polymorphic HLA class I molecules has repeatedly been associated with HIV-1 control and progression to AIDS, accounting for up to 12% of the variation in HIV-1 set point viral load (spVL). This suggests a key role in disease control for HLA presentation 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.1812548116
更新日期:2019-01-15 00:00:00
abstract::We investigated patterns of genetic diversity of Plasmodium falciparum associated with its two main African vectors: Anopheles gambiae and Anopheles funestus. We dissected 10,296 wild-caught mosquitoes from three tropical sites, two in Cameroon (Simbock and Tibati, separated by 320 km) and one in Kenya (Rota, >2,000 k...
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.0702715104
更新日期:2007-05-08 00:00:00
abstract::The temperature dependence of migration rate and of the thermotactic sensitivity of pseudoplasmodia of Dictyostelium discoideum has been measured. Migration rate increases with temperature to 20 degrees, is temperature insensitive from 20 degrees to 27.5 degrees, and decreases with temperature to 29 degrees, above whi...
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.74.5.2007
更新日期:1977-05-01 00:00:00
abstract::The emergence of Vibrio cholerae O139 Bengal during 1992-1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of eit...
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.0337468100
更新日期:2003-02-04 00:00:00
abstract::Numerous investigations have focused on DNA damage induced by ionizing radiation; however, photoionization threshold energies of nucleic acid components in aqueous solution are not known. Herein, data from gas-phase photoelectron experiments have been combined with results from self-consistent field and post-self-cons...
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.95.10.5550
更新日期:1998-05-12 00:00:00
abstract::Cyclonic atmospheric vortices of varying intensity, collectively known as low-pressure systems (LPS), travel northwest across central India and produce more than half of the precipitation received by that fertile region and its ∼600 million inhabitants. Yet, future changes in LPS activity are poorly understood, due in...
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.1709031115
更新日期:2018-03-13 00:00:00
abstract::Experimental and computational simulations revealed that boron clusters, which favor planar (2D) structures up to 18 atoms, prefer 3D structures beginning at 20 atoms. Using global optimization methods, we found that the B20 neutral cluster has a double-ring tubular structure with a diameter of 5.2 A. For the B(-)20 a...
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.0408132102
更新日期:2005-01-25 00:00:00
abstract::After five decades of largely serendipitous (albeit formidable) progress, catalyst design in Ziegler-Natta olefin polymerization, i.e., the rational implementation of new active species to target predetermined polyolefin architectures, has ultimately become a realistic ambition, thanks to a much deeper fundamental und...
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.0602856103
更新日期:2006-10-17 00:00:00
abstract::McKay et al. [(1996) Science 273, 924-930] suggested that carbonate globules in the meteorite ALH84001 contained the fossil remains of Martian microbes. We have characterized a subpopulation of magnetite (Fe(3)O(4)) crystals present in abundance within the Fe-rich rims of these carbonate globules. We find these Martia...
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.051500898
更新日期:2001-02-27 00:00:00