Abstract:
:A short, highly stereoselective (over 97%) synthesis of all-trans squalene is described. Starting with succinaldehyde, a tetraenedichlorodione having the complete squalene skeleton with the four internal trans olefinic bonds has been developed in four steps involving a sequence of two double Claisen rearrangements. Three simple operations convert this intermediate into squalene.
journal_name
Proc Natl Acad Sci U S Aauthors
Werthemann L,Johnson WSdoi
10.1073/pnas.67.3.1465subject
Has Abstractpub_date
1970-11-01 00:00:00pages
1465-7issue
3eissn
0027-8424issn
1091-6490journal_volume
67pub_type
杂志文章abstract::CD4+ T cells recognize major histocompatibility complex (MHC) class II-bound peptides that are primarily obtained from extracellular sources. Endogenously synthesized proteins that readily enter the MHC class I presentation pathway are generally excluded from the MHC class II presentation pathway. We show here that en...
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.92.16.7217
更新日期:1995-08-01 00:00:00
abstract::The structure of activated pig heart aconitase [citrate(isocitrate) hydro-lyase, EC 4.2.1.3] containing a [4Fe-4S] cluster has been refined at 2.5-A resolution to a crystallographic residual of 18.2%. Comparison of this structure to the recently determined 2.1-A resolution structure of the inactive enzyme containing 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.86.10.3639
更新日期:1989-05-01 00:00:00
abstract::The archaeological record shows that typically human cultural traits emerged at different times, in different parts of the world, and among different hominin taxa. This pattern suggests that their emergence is the outcome of complex and nonlinear evolutionary trajectories, influenced by environmental, demographic, and...
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.1620752114
更新日期:2017-07-25 00:00:00
abstract::Expression of alphavbeta3- or alphavbeta5-integrins and selectins is widespread on blood cells and endothelial cells. Here we report that human tumor cells injected s.c. into mice lacking beta3- or beta3/beta5-integrins or various selectins show enhanced tumor growth compared with growth in control mice. There was inc...
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.0307289101
更新日期:2004-01-20 00:00:00
abstract::Coincidence cloning allows the isolation of sequences held in common by two genomic DNA populations. Human DNA from two human-hamster hybrid cell lines was amplified by Alu-repeat primers (Alu PCR) and the products originating from the shared human chromosomal region were cloned. To achieve this, human sequences were ...
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.88.15.6765
更新日期:1991-08-01 00:00:00
abstract::Hodgkin disease (HD) is characterized by a small number of malignant Hodgkin and Reed-Sternberg (H/RS) cells among a major population of nonmalignant cells. The analysis of H/RS cells has been hampered by their low frequency and fragility. Here, we describe the isolation of viable H/RS cells from HD affected tissues 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.95.17.10117
更新日期:1998-08-18 00:00:00
abstract::Frizzled polypeptides are integral membrane proteins that recently were shown to function as receptors for Wnt signaling molecules. Here, we report the identification of a novel, secreted 36-kDa protein that contains a region homologous to a putative Wnt-binding domain of Frizzleds. This protein, called Frizzled-relat...
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.94.13.6770
更新日期:1997-06-24 00:00:00
abstract::To efficiently represent all of the possible rewards in the world, dopaminergic midbrain neurons dynamically adapt their coding range to the momentarily available rewards. Specifically, these neurons increase their activity for an outcome that is better than expected and decrease it for an outcome worse than expected,...
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.1119969109
更新日期:2012-03-13 00:00:00
abstract::Ligand specificity of a murine gammadelta T-cell receptor-expressing hybridoma (KN6) derived from adult thymocytes has been analyzed in detail. The molecule recognized by the KN6 gammadelta T-cell receptor is expressed on syngeneic cells of various sources (peritoneal macrophages, thymocytes, spleen cells, and Abelson...
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.86.15.5928
更新日期:1989-08-01 00:00:00
abstract::The neuropeptide oxytocin has been implicated in the mediation of several forms of affiliative behavior including parental care, grooming, and sex behavior. Here we demonstrate that species from the genus Microtus (voles) selected for differences in social affiliation show contrasting patterns of oxytocin receptor exp...
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.89.13.5981
更新日期:1992-07-01 00:00:00
abstract::Particles composed of secondary organic material (SOM) are abundant in the lower troposphere. The viscosity of these particles is a fundamental property that is presently poorly quantified yet required for accurate modeling of their formation, growth, evaporation, and environmental impacts. Using two unique techniques...
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.1219548110
更新日期:2013-05-14 00:00:00
abstract::We describe two Drosophila melanogaster transcription units that are highly homologous to a rat Na+-channel cDNA. They appear to encode the major subunits of two distinct Na+-channel proteins. One of these maps to the second chromosome and is identical to a Na+-channel gene whose partial sequence has been previously 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.86.6.2079
更新日期:1989-03-01 00:00:00
abstract::Compositeness of the electron may show up in a very small deviation of the measured electron g factor from one calculated for a point electron by quantum electrodynamics. The precision of our g measurements is currently limited by an interaction of the cyclotron motion with standing waves in the trap cavity containing...
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.89.5.1681
更新日期:1992-03-01 00:00:00
abstract::A monoclonal antibody has been developed that recognizes a mouse lymphocyte antigen, Ly-23, that is controlled by an H-3 histocompatibility complex-linked gene on the second chromosome. Competitive binding experiments demonstrate that this antigen is distinct from the polymorphic beta 2-microglobulin antigen, which al...
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.80.21.6620
更新日期:1983-11-01 00:00:00
abstract::Recent studies have shown that orthotopic (transurethral) transplantation of human bladder cancer cell lines into nude mice permits tumor growth that accurately reflects their clinical malignant status in the original host. Thus, such a system allows a unique opportunity to analyze the genetic events involved in the c...
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.87.22.9047
更新日期:1990-11-01 00:00:00
abstract::The blind Mexican cave tetra, Astyanax mexicanus, is a unique model system for the study of parallelism and the evolution of cave-adapted traits. Understanding the genetic basis for these traits has recently become feasible thanks to production of a genome-wide linkage map and quantitative trait association analyses. ...
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.0806238105
更新日期:2008-12-23 00:00:00
abstract::A Down's syndrome associated gene, Single Minded 2 gene short form (SIM2-s), is specifically expressed in colon tumors but not in the normal colon. Antisense inhibition of SIM2-s in a RKO-derived colon carcinoma cell line causes growth inhibition, apoptosis, and inhibition of tumor growth in a nude mouse tumoriginicit...
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.0505484102
更新日期:2005-09-06 00:00:00
abstract::Rad51 is a highly conserved eukaryotic homolog of the prokaryotic recombination protein RecA, which has been shown to function in both recombinational repair of DNA damage and meiotic recombination in yeast. In primary murine B cells cultured with lipopolysaccharide (LPS) to stimulate heavy chain class switch recombin...
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.93.19.10222
更新日期:1996-09-17 00:00:00
abstract::Excessive activation of calmodulin kinase II (CaMKII) causes arrhythmias and heart failure, but the cellular mechanisms for CaMKII-targeted proteins causing disordered cell membrane excitability and myocardial dysfunction remain uncertain. Failing human cardiomyocytes exhibit increased CaMKII and voltage-gated Ca(2+) ...
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.0913760107
更新日期:2010-03-16 00:00:00
abstract::We have used in vitro motility assays to investigate the mechanism of kinetochore function in the budding yeast Saccharomyces cerevisiae. Functional centromeric DNA plus a tripartite centromere binding protein complex, CBF3, was found to be necessary but not sufficient for in vitro kinetochore activity. A fourth requi...
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.91.15.7212
更新日期:1994-07-19 00:00:00
abstract::Myosin V is an unconventional myosin proposed to be processive on actin filaments, analogous to kinesin on a microtubule [Mehta, A. D., et al. (1999) Nature (London) 400, 590-593]. To ascertain the unique properties of myosin V that permit processivity, we undertook a detailed kinetic analysis of the myosin V motor. W...
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.96.24.13726
更新日期:1999-11-23 00:00:00
abstract::This paper presents a statistical framework for harnessing online activity data to better understand how people make decisions. Building on insights from cognitive science and decision theory, we develop a discrete choice model that allows for exploratory behavior and multiple stages of decision making, with different...
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.1522494113
更新日期:2016-09-20 00:00:00
abstract::Initiation of X chromosome inactivation requires the presence, in cis, of the X inactivation center (XIC). The Xist gene, which lies within the XIC region in both human and mouse and has the unique property of being expressed only from the inactive X chromosome in female somatic cells, is known to be essential for X 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.96.12.6841
更新日期:1999-06-08 00:00:00
abstract::The substance P (SP)-preferring receptor neurokinin-1 receptor (NK-1R) has two forms: a full-length receptor consisting of 407 aa and a truncated receptor consisting of 311 aa. These two receptors differ in the length of the C terminus of NK-1R. We studied the undifferentiated and phorbol myristate acetate (PMA)-diffe...
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.0602563103
更新日期:2006-05-16 00:00:00
abstract::The N-terminal domain of the vaccinia virus protein E3L (Z alpha(E3L)) is essential for full viral pathogenicity in mice. It has sequence similarity to the high-affinity human Z-DNA-binding domains Z alpha(ADAR1) and Z alpha(DLM1). Here, we report the solution structure of Z alpha(E3L) and the chemical shift map of it...
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.0308612100
更新日期:2004-03-02 00:00:00
abstract::We have generated RANK (receptor activator of NF-kappaB) nullizygous mice to determine the molecular genetic interactions between osteoprotegerin, osteoprotegerin ligand, and RANK during bone resorption and remodeling processes. RANK(-/-) mice lack osteoclasts and have a profound defect in bone resorption and remodeli...
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.97.4.1566
更新日期:2000-02-15 00:00:00
abstract::Indirect reciprocity is a mechanism for cooperation based on shared moral systems and individual reputations. It assumes that members of a community routinely observe and assess each other and that they use this information to decide who is good or bad, and who deserves cooperation. When information is transmitted pub...
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.1810565115
更新日期:2018-11-27 00:00:00
abstract::The preservation of our cultural heritage is of great importance to future generations. Despite this, significant problems have arisen with the conservation of waterlogged wooden artifacts. Three major issues facing conservators are structural instability on drying, biological degradation, and chemical degradation on ...
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.1406037111
更新日期:2014-12-16 00:00:00
abstract::Preliminary x-ray diffraction data from single crystals of the MoFe proteins of nitrogenase from Clostridium pasteurianum and Azotobacter vinelandii have been obtained. Both protein crystals belong to the P2(1) space group. The MoFe protein crystals from C. pasteurianum and A. vinelandii diffract to angles correspondi...
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.79.2.378
更新日期:1982-01-01 00:00:00
abstract::Influenza hemagglutinin (HA) glycoprotein is the primary surface antigen targeted by the host immune response and a focus for development of novel vaccines, broadly neutralizing antibodies (bnAbs), and therapeutics. HA enables viral entry into host cells via receptor binding and membrane fusion and is a validated targ...
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.2006893117
更新日期:2020-08-04 00:00:00