Abstract:
:Cultures were prepared of embryonic cells from Drosophila melanogaster. Neurons and myocytes differentiated in vitro from their respective stem cells. Electron microscopy showed that neuromuscular junctions formed where axons contacted myocytes. Electrical stimuli were applied to axons and these caused contractions of innervated myocytes. This is the first report of insect or other invertebrate neuromuscular junctions differentiating in vitro. In addition, this is the first system reported in which the neurons, myocytes, and junctions are completely differentiated in vitro from neuroblasts and myoblasts.
journal_name
Proc Natl Acad Sci U S Aauthors
Seecof RL,Teplitz RL,Gerson I,Ikeda K,Donady Jdoi
10.1073/pnas.69.3.566subject
Has Abstractpub_date
1972-03-01 00:00:00pages
566-70issue
3eissn
0027-8424issn
1091-6490journal_volume
69pub_type
杂志文章abstract::Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a "critical period" for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their inn...
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.1200705109
更新日期:2012-10-16 00:00:00
abstract::Retroviral gene expression is inhibited in embryonal carcinoma (EC) cells. We have constructed a recombinant retroviral vector that is capable of expressing the neomycin-resistance (neo) gene in EC cells. The critical modification that permits expression of the neo gene is the insertion of a composite simian virus 40 ...
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.81.22.7137
更新日期:1984-11-01 00:00:00
abstract::Somatic hypermutation (SHM) and class-switch recombination (CSR) of the Ig gene require both the transcription of the locus and the expression of activation-induced cytidine deaminase (AID). During CSR, AID decreases the amount of topoisomerase I (Top1); this decrease alters the DNA structure and induces cleavage in 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.1114522108
更新日期:2011-11-29 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.90.21.10159
更新日期:1993-11-01 00:00:00
abstract::Group II intron RNAs self-splice in vitro but only at high salt and/or Mg2+ concentrations and have been thought to require proteins to stabilize their active structure for efficient splicing in vivo. Here, we show that a DEAD-box protein, CYT-19, can by itself promote the splicing and reverse splicing of the yeast aI...
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.0600332103
更新日期:2006-03-07 00:00:00
abstract::Levinthal's paradox is that finding the native folded state of a protein by a random search among all possible configurations can take an enormously long time. Yet proteins can fold in seconds or less. Mathematical analysis of a simple model shows that a small and physically reasonable energy bias against locally unfa...
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.89.1.20
更新日期:1992-01-01 00:00:00
abstract::Inflammation is a major factor in heart disease. IκB kinase (IKK) and its downstream target NF-κB are regulators of inflammation and are activated in cardiac disorders, but their precise contributions and targets are unclear. We analyzed IKK/NF-κB function in the heart by a gain-of-function approach, generating an ind...
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.1116584109
更新日期:2012-07-17 00:00:00
abstract::Using chimeric recombinants transfected into HeLa cells and a transient expression assay, we demonstrate that the 5'-flanking region of the pS2 gene from position -428 to position -324 exhibits both constitutive and estrogen-inducible enhancer activity. The estrogen-inducible activity, but not the constitutive activit...
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.86.4.1218
更新日期:1989-02-01 00:00:00
abstract::Vanilloid receptor subunit 1 (VR1) appears to play a critical role in the transduction of noxious chemical and thermal stimuli by sensory nerve endings in peripheral tissues. Thus, VR1 antagonists are useful compounds to unravel the contribution of this receptor to pain perception, as well as to induce analgesia. We 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.022285899
更新日期:2002-02-19 00:00:00
abstract::Our ability to interpret seismic observations including the seismic discontinuities and the density and velocity profiles in the earth's interior is critically dependent on the accuracy of pressure measurements up to 364 GPa at high temperature. Pressure scales based on the reduced shock-wave equations of state alone ...
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.0609013104
更新日期:2007-05-29 00:00:00
abstract::Soil systems are being increasingly exposed to the interactive effects of biological invasions and climate change, with rising temperatures expected to benefit alien over indigenous species. We assessed this expectation for an important soil-dwelling group, the springtails, by determining whether alien species show br...
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.1715598115
更新日期:2018-01-02 00:00:00
abstract::The polypeptide chain initiation factor 2 (eIF-2) binds phospholipid (PL) and becomes a potent inhibitor of translation in hemin-supplemented reticulocyte lysates. This binding is markedly reduced by prior treatment of eIF-2 with N-ethylmaleimide. Although PL is probably bound by all three eIF-2 subunits, our results ...
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.83.18.6711
更新日期:1986-09-01 00:00:00
abstract::NAD(P)H:quinone oxidoreductase (NQOR; EC 1.6.99.2) is a homodimeric enzyme which catalyzes the reduction of quinones, azo dyes, and other electron acceptors by NADPH or NADH. To pursue subunit functional studies, we expressed a wild-type/mutant heterodimer of NQOR in Escherichia coli. The wild-type subunit of the hete...
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.92.4.1043
更新日期:1995-02-14 00:00:00
abstract::R. A. Fisher's 1930 "reproductive value" is defined as the contribution made by a population's initial age elements to its asymptotically dominating exponential growth mode. For the Leslie discrete-time model, it is the characteristic row vector of the Leslie matrix, and for the integral-equation model of Lotka the si...
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.74.11.5189
更新日期:1977-11-01 00:00:00
abstract::During exercise, increased energy demands are met by increased glucose production that occurs simultaneously with the increased glucose uptake. We had previously observed that, during exercise, metabolic clearance rate of glucose (MCR) increases markedly in normal, but only marginally in poorly controlled diabetic dog...
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.88.4.1296
更新日期:1991-02-15 00:00:00
abstract::The retinylidene chromophore mutant (Y185F) of bacteriorhodopsin, in which Tyr-185 is substituted by phenylalanine, is examined and compared with wild-type bacteriorhodopsin expressed in Escherichia coli; both were reinstituted similarly in vesicles. The Y185F mutant shows (at least) two distinct spectra at neutral pH...
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.87.11.4103
更新日期:1990-06-01 00:00:00
abstract::What are the origins of humans' capacity to represent social relations? We approached this question by studying human infants' understanding of social dominance as a stable relation. We presented infants with interactions between animated agents in conflict situations. Studies 1 and 2 targeted expectations of stabilit...
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.1113194109
更新日期:2012-05-01 00:00:00
abstract::The c-ras family is a set of c-onc genes that are highly conserved in vertebrates. The genes in this family are homologous to the transforming genes of Harvey and Kirsten murine sarcoma viruses (v-Ha-ras and v-Ki-ras, respectively). Using an in situ molecular hybridization method, we detected three sites on the human ...
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.80.15.4794
更新日期:1983-08-01 00:00:00
abstract::It is well established that the medial-temporal lobe (MTL) is critical for recognition memory. The MTL is known to be composed of distinct structures that are organized in a hierarchical manner. At present, it remains controversial whether lower structures in this hierarchy, such as perirhinal cortex, support memory f...
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:2007-10-09 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:2008-09-02 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.1706694115
更新日期:2018-06-05 00:00:00
abstract::Tactoids are nuclei of an orientationally ordered nematic phase that emerge upon cooling the isotropic phase. In addition to providing a natural setting for exploring chromonics under confinement, we show that tactoids can also serve as optical probes to delineate the role of temperature and concentration in the aggre...
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.1614620114
更新日期:2017-04-11 00:00:00
abstract::Chronic hypoxia causes pulmonary hypertension with smooth muscle cell proliferation and matrix deposition in the wall of the pulmonary arterioles. We demonstrate here that hypoxia also induces a pronounced inflammation in the lung before the structural changes of the vessel wall. The proinflammatory action of hypoxia ...
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.161272598
更新日期:2001-07-17 00:00:00
abstract::The mechanism of preferential transmission (i.e., maternal inheritance) of cytoplasmic genes was investigated with chloroplast DNA of Chlamydomonas as a model system. The behavior of nuclear and chloroplast DNAs were compared in the sexual cycle; DNAs from male and female parents were distinguished by labeling with (1...
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.69.9.2410
更新日期:1972-09-01 00:00:00
abstract::Spo11 and the Rad50-Mre11 complex have been indirectly implicated in processes associated with DNA replication. These proteins also have been shown to have early meiotic roles essential for the formation of a programmed DNA double-strand break known in Saccharomyces cerevisiae to initiate meiotic recombination. In bot...
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.190346097
更新日期:2000-09-12 00:00:00
abstract::The severe acute respiratory syndrome coronavirus 2 originated in Wuhan, China at the end of 2019 and rapidly spread in more than 100 countries. Researchers in different fields have been working on finding explanations for the unequal impact of the virus and deaths from the associated coronavirus disease 2019 (COVID-1...
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.2008581117
更新日期:2020-08-11 00:00:00
abstract::The synthetic, biologically active, [Phe4Val6] analog of natural antamanide has been crystallized from a solution containing calcium nitrate, acetone, and acetonitrile. The crystal does not contain any Ca2+ ions but does contain 12 water molecules per peptide molecule. The conformation of this dodecahydrate is identic...
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.74.7.2602
更新日期:1977-07-01 00:00:00
abstract::Modern practice for training classification deepnets involves a terminal phase of training (TPT), which begins at the epoch where training error first vanishes. During TPT, the training error stays effectively zero, while training loss is pushed toward zero. Direct measurements of TPT, for three prototypical deepnet 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.2015509117
更新日期:2020-10-06 00:00:00
abstract::The labeled inorganic phosphate formed by enzymatic hydrolysis of [gamma-18O]ATP in normal water was derivatized to trimethyl phosphate and analyzed for the proportions of [18O3]Pi, [18O2]Pi, [18O1]Pi, and [18O0]Pi. The proportions observed were correlated with the kinetics of intermediate exchange by using a kinetic ...
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.78.4.2067
更新日期:1981-04-01 00:00:00
abstract::We have developed a gene-fusion system based on the Escherichia coli beta-glucuronidase gene (uidA). The uidA gene has been cloned from E. coli K-12 and its entire nucleotide sequence has been determined. beta-Glucuronidase has been purified to homogeneity and characterized. The enzyme has a subunit molecular weight o...
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.83.22.8447
更新日期:1986-11-01 00:00:00