Abstract:
:A retinoid was isolated by a multistep procedure from the small intestines of vitamin A-deficient rats given a single dose of retinoic acid. The compound, designated 8II, was pure, as demonstrated by four high-pressure liquid chromatographic procedures. It was positively identified as 5,8-oxyretinoic acid by ultraviolet spectrophotometry, mass spectrometry, and spectral and chromatographic comparison to known compounds. It is probable that 5,8-oxyretinoic acid was produced from 5,6-epoxyretinoic acid under the acidic conditions used in the isolation. It is highly probable, therefore, that the natural product is 5,6-epoxyretinoic acid.
journal_name
Proc Natl Acad Sci U S Aauthors
Napoli JL,McCormick AM,Schnoes HK,DeLuca HFdoi
10.1073/pnas.75.6.2603subject
Has Abstractpub_date
1978-06-01 00:00:00pages
2603-5issue
6eissn
0027-8424issn
1091-6490journal_volume
75pub_type
杂志文章abstract::Tobacco mosaic virus (TMV) RNA was encapsulated in large, unilamellar phospholipid vesicles (liposomes), and the encapsulated TMV RNA was shown to be infectious when incubated with tobacco protoplasts under appropriate conditions. Maximal virus production in protoplasts was observed after their incubation with TMV RNA...
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.79.6.1859
更新日期:1982-03-01 00:00:00
abstract::Reports of structural differences between the brains of men and women, heterosexual and homosexual men, and male-to-female transsexuals and other men have been offered as evidence that the behavioral differences between these groups are likely caused by differences in the early development of the brain. However, a pos...
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.96.13.7538
更新日期:1999-06-22 00:00:00
abstract::Mobile ectothermic animals can control their body temperatures by selecting specific thermal conditions in the environment, but embryos--trapped within an immobile egg and lacking locomotor structures--have been assumed to lack that ability. Falsifying that assumption, our experimental studies show that even early sta...
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.1102965108
更新日期:2011-06-07 00:00:00
abstract::Lod scores provide a method to unify linkage tests based on identity by descent and identity in marker state while permitting selection of the most informative individuals through their disease-related phenotypes and markers in relatives. After parametric lods are reviewed, a nonparametric approach that depends on a s...
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.93.8.3471
更新日期:1996-04-16 00:00:00
abstract::Contingency models of feeding compare the energy per unit time gained from utilizing a resource unit of a particular kind (food types, habitat patches, time periods) against that energy/time expected if the unit is skipped. Optimally, an animal should reject the particular unit if and only if the former energy/time is...
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.71.10.4169
更新日期:1974-10-01 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
abstract::Newly translated tubulin molecules undergo a series of complex interactions with nascent chain-binding chaperones, including prefoldin (PFD) and chaperonin-containing TCP-1 (CCT). By screening for oryzalin hypersensitivity, we identified several mutants of Arabidopsis that have lesions in PFD subunits. The pfd6-1 muta...
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.0808652105
更新日期:2008-11-18 00:00:00
abstract::The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between anno Domini (A.D.) 1250 and 1810, coincident with sola...
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.0603118103
更新日期:2006-06-13 00:00:00
abstract::Group A Streptococcus (GAS) and other bacterial pathogens are known to interact with integrins as an initial step in a complex pathway of bacterial ingestion by host cells. Efficient GAS invasion depends on the interaction of bound fibronectin (Fn) with integrins and activation of integrin signaling. TGF-beta1 regulat...
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.0506668103
更新日期:2006-02-14 00:00:00
abstract::Differences in T cell receptor (TCR) signaling initiated by interactions among TCRs, coreceptors, and self-peptide-MHC complexes determine the outcome of CD4 versus CD8 lineage of T cell differentiation. The H-2Ld and Kbm3 alloreactive 2C TCR is positively selected by MHC class I Kb and a yet-to-be identified nonclass...
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.0510561103
更新日期:2006-02-07 00:00:00
abstract::The A(2A)R is largely coexpressed with D(2)Rs and enkephalin mRNA in the striatum where it modulates dopaminergic activity. Activation of the A(2A)R antagonizes D(2)R-mediated behavioral and neurochemical effects in the basal ganglia through a mechanism that may involve direct A(2A)R-D(2)R interaction. However, whethe...
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.98.4.1970
更新日期:2001-02-13 00:00:00
abstract::Because previous studies showed that polyunsaturated fatty acids can reduce the contraction rate of spontaneously beating heart cells and have antiarrhythmic effects, we examined the effects of the fatty acids on the electrophysiology of the cardiac cycle in isolated neonatal rat cardiac myocytes. Exposure of cardiomy...
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.92.9.3997
更新日期:1995-04-25 00:00:00
abstract::Telomerase is an RNA-directed DNA polymerase, composed of RNA and protein subunits, that replicates the telomere ends of linear eukaryotic chromosomes. Using a genetic strategy described here, we identify the product of the EST2 gene, Est2p, as a subunit of telomerase in the yeast Saccharomyces cerevisiae. Est2p is re...
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.94.17.9202
更新日期:1997-08-19 00:00:00
abstract::Polycomb-group (Pc-G) proteins ensure late maintenance of transcriptional repression outside the expression domain of target genes in flies and vertebrates. They act in complexes, presumably by modulating chromatin structure. In Drosophila, they have been found to be associated with transcriptionally inactive loci but...
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.2237046100
更新日期:2003-11-11 00:00:00
abstract::The way general anesthetics cause their clinically useful effects on the nervous system is not known. Since the principal determinant of the potency of these agents is their solubility in oil, the role of chemical structure in affecting anesthetic targets has been obscured. In this work, we use an intense beam of ligh...
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.91.6.2135
更新日期:1994-03-15 00:00:00
abstract::Aluminum (Al) is the most abundant metal in the Earth's crust, but its trivalent ionic form is highly toxic to all organisms at low concentrations. How Al enters cells has not been elucidated in any organisms. Herein, we report a transporter, Nrat1 (Nramp aluminum transporter 1), specific for trivalent Al ion in rice....
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.1004949107
更新日期:2010-10-26 00:00:00
abstract::Exposure of 3T3/A31 cells to serum-free medium, one type of apoptotic stimulus, causes a rapid increase in the sphingosine (Sph) level, which initiates a series of processes: (i) activation of caspase 3 through an enhanced "cascade" of caspases, (ii) release of the C-terminal-half kinase domain of PKCdelta (PKCdelta 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.0406536101
更新日期:2004-10-12 00:00:00
abstract::We have cloned a murine cDNA encoding a tyrosine kinase receptor with about 90% similarity to the chicken fibroblast growth factor (FGF) receptor and the human fms-like gene (FLG) tyrosine kinase. This mouse receptor lacks 88 amino acids in the extracellular portion, leaving only two immunoglobulin-like domains compar...
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.87.11.4378
更新日期:1990-06-01 00:00:00
abstract::Here we test the hypothesis that high-altitude native resident Tibetan women with genotypes for high oxygen saturation of hemoglobin, and thus less physiological hypoxic stress, have higher Darwinian fitness than women with low oxygen saturation genotypes. Oxygen saturation and genealogical data were collected from re...
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
doi:10.1073/pnas.0405949101
更新日期:2004-09-28 00:00:00
abstract::The DC and DX subregions of the human major histocompatibility complex (MHC) have been cloned from a cosmid library made from a human B-cell line, Priess. The DC subregion, 48 kilobases, includes the DC alpha and DC beta genes. A second DC-like region, the DX subregion, 35 kilobases, contains the DX alpha gene and a n...
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.82.10.3410
更新日期:1985-05-01 00:00:00
abstract::Supernatant fractions (300,000 x g, 60 min) from homogenates of rat liver, heart, and skeletal muscle, dog liver, and rabbit liver prepared without detergent in the homogenization medium (referred to as S300) are shown to contain an activity that restores Mg2+-dependent fluoride- and guanine nucleotide-stimulated cycl...
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.77.7.3836
更新日期:1980-07-01 00:00:00
abstract::Dust grains of organic matter were the main reservoir of C and N in the forming Solar System and are thus considered to be an essential ingredient for the emergence of life. However, the physical environment and the chemical mechanisms at the origin of these organic grains are still highly debated. In this study, we r...
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.1808101115
更新日期:2018-08-21 00:00:00
abstract::Serotonin (5-HT) controls a wide range of biological functions. In the brain, its implication as a neurotransmitter and in the control of behavioral traits has been largely documented. At the periphery, its modulatory role in physiological processes, such as the cardiovascular function, is still poorly understood. The...
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.2233056100
更新日期:2003-11-11 00:00:00
abstract::Cranial neural crest cells (crNCCs) migrate from the neural tube to the pharyngeal arches (PAs) of the developing embryo and, subsequently, differentiate into bone and connective tissue to form the mandible. Within the PAs, crNCCs respond to local signaling cues to partition into the proximo-distally oriented subdomai...
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.1603930113
更新日期:2016-07-05 00:00:00
abstract::Bacterial RNases catalyze the turnover of RNA and are essential for gene expression and quality surveillance of transcripts. In Escherichia coli, the exoribonucleases RNase R and polynucleotide phosphorylase (PNPase) play critical roles in degrading RNA. Here, we developed an optical-trapping assay to monitor the tran...
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.1514028112
更新日期:2015-12-08 00:00:00
abstract::MurG is an essential glycosyltransferase that forms the glycosidic linkage between N-acetyl muramyl pentapeptide and N-acetyl glucosamine in the biosynthesis of the bacterial cell wall. This enzyme is a member of a major superfamily of NDP-glycosyltransferases for which no x-ray structures containing intact substrates...
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.0235749100
更新日期:2003-02-04 00:00:00
abstract::The mechanism of proton transfer from the bulk into the membrane protein interior was studied. The light-induced reduction of a bound ubiquinone molecule Q(B) by the photosynthetic reaction center is accompanied by proton trapping. We used kinetic spectroscopy to measure (i) the electron transfer to Q(B) (at 450 nm), ...
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.96.23.13159
更新日期:1999-11-09 00:00:00
abstract::The Bill and Melinda Gates Foundation supports an ambitious portfolio of novel vaccines, drug regimens, and diagnostic tools for tuberculosis (TB). We elicited the expected efficacies and improvements of the novel interventions in discussions with the foundations managing their development. Using an age-structured mat...
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.0901720106
更新日期:2009-08-18 00:00:00
abstract::Predominant usage of V beta 8.2 gene segments, encoding a T-cell receptor (TCR) beta chain variable region, has been reported for pathogenic Lewis rat T cells reactive to myelin basic protein (MBP). However, up to 75% of the alpha/beta T cells in a panel of MBP-specific T-cell lines did not display TCR V beta 8.2, V b...
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.92.13.5850
更新日期:1995-06-20 00:00:00
abstract::The method of anticodon loop replacement has been used to make derivatives of yeast tRNAPhe. By constructing tRNAs with a CUA anticodon, complementary to the amber (UAG) terminator, functional amber suppressor tRNAs were produced. The activity of these tRNAs was assayed in a mammalian cell-free protein synthesizing sy...
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.79.23.7127
更新日期:1982-12-01 00:00:00