Abstract:
:The formation of nerve-muscle junctions in monolayer cultures of embryonic muscle and spinal cord cells is described. Muscle-forming cells (myoblasts) from leg muscles of 12-day chick embryos were separated with trypsin and cultured on a collagen substrate for two days. Suspensions of ventral spinal cord cells from six-day chick embryos were then plated over the differentiating muscle cells. The cultures were subsequently examined by electron microscopy and in silver-stained light microscopic preparations. After 10-12 days in culture, irregular thickenings were observed along the nerve cell processes in contact with the muscle fibers which by that time had undergone advanced differentiation (myogenesis). By electron microscopy it was demonstrated that many of the nerve-muscle contacts had the characteristics of a synapse. Some aspects of the fine structure of these junctions are described. The possibilities raised by these findings with respect to innervation mechanisms and specificities in nerve-muscle interactions are briefly discussed.
journal_name
Proc Natl Acad Sci U S Aauthors
Shimada Y,Fischman DA,Moscona AAdoi
10.1073/pnas.62.3.715subject
Has Abstractpub_date
1969-03-01 00:00:00pages
715-21issue
3eissn
0027-8424issn
1091-6490journal_volume
62pub_type
杂志文章abstract::Ultraviolet (UV)-stimulated nonconservative DNA synthesis has been observed in E. coli rendered permeable to nucleoside triphosphates by exposure to toluene. This synthesis is detected in toluenized cells in which the background of UV-independent DNA synthesis is reduced by use of dnaB mutants temperature-sensitive fo...
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.70.1.129
更新日期:1973-01-01 00:00:00
abstract::A hallmark of the pathology of Alzheimer's disease is the accumulation of the microtubule-associated protein tau into fibrillar aggregates. Recent studies suggest that they accumulate because cytosolic chaperones fail to clear abnormally phosphorylated tau, preserving a pool of toxic tau intermediates within the neuro...
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.0709180105
更新日期:2008-03-04 00:00:00
abstract::Whether mitotic structures like the centrosome can self-organize from the regulated mobility of their dynamic protein components remains unclear. Here, we combine fluorescence spectroscopy and chemical genetics to study in living cells the diffusion of polo-like kinase 1 (PLK1), an enzyme critical for centrosome matur...
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.1101112108
更新日期:2011-05-31 00:00:00
abstract::Helminthosporoside is a host-specific toxin produced by Helminthosporium sacchari, both in culture and in infected sugarcane tissue. The susceptibility of any given clone of sugarcane to disease is invariably associated with the presence of a toxin-binding protein. This report presents evidence for the presence of 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.71.4.1413
更新日期:1974-04-01 00:00:00
abstract::The early reactions in the catabolism of quinic acid in Neurospora crassa are controlled by at least four genes which are clustered on linkage group VII. Three of the loci (qa-2, qa-4, and qa-3) encode enzymes that convert quinic acid to protocatechuic acid. The fourth gene (qa-1) encodes a positive regulatory protein...
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.78.8.5086
更新日期:1981-08-01 00:00:00
abstract::Increasing evidence highlights a role for the immune system in the pathogenesis of autism spectrum disorder (ASD), as immune dysregulation is observed in the brain, periphery, and gastrointestinal tract of ASD individuals. Furthermore, maternal infection (maternal immune activation, MIA) is a risk factor for ASD. Mode...
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.1202556109
更新日期:2012-07-31 00:00:00
abstract::The roots and stems of dicotyledonous plants thicken by the cell proliferation in the cambium. Cambial proliferation changes in response to environmental factors; however, the molecular mechanisms that regulate cambial activity are largely unknown. The quadruple Arabidopsis thaliana mutant atipt1;3;5;7, in which 4 gen...
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.0805619105
更新日期:2008-12-16 00:00:00
abstract::Since its discovery in 1907, polyploidy has been recognized as an important phenomenon in vascular plants, and several lines of evidence indicate that most, if not all, plant species ultimately have a polyploid ancestry. However, previous estimates of the frequency of polyploid speciation suggest that the formation an...
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.0811575106
更新日期:2009-08-18 00:00:00
abstract::P-glycoprotein is an ATP-binding cassette multidrug transporter that actively transports chemically diverse substrates across the lipid bilayer. The precise molecular mechanism underlying transport is not fully understood. Here, we present crystal structures of a eukaryotic P-glycoprotein homolog, CmABCB1 from Cyanidi...
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.1321562111
更新日期:2014-03-18 00:00:00
abstract::Erythroid Krüppel-like factor (EKLF), which binds to the CACCC box in the beta-globin promoter, is required for the expression of the beta-globin gene in adult erythroid cells. It was recently demonstrated that EKLF is also required for the activity of the beta-globin locus control region (LCR) 5'HS3. Some evidence su...
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.96.18.10051
更新日期:1999-08-31 00:00:00
abstract::We used gene knockout mice to explore the role of Angiopoietin-like-4 (Angptl4) in lipid metabolism as well as to generate anti-Angptl4 mAbs with pharmacological activity. Angptl4 -/- mice had lower triglyceride (TG) levels resulting both from increased very low-density lipoprotein (VLDL) clearance and decreased VLDL ...
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.0705041104
更新日期:2007-07-10 00:00:00
abstract::The Hyal-1 locus, which we have previously described and mapped to mouse chromosome 9, influences the serum levels and molecular weight forms of hyaluronidase. We have also shown that the growth of two transplantable tumors, the 3LL carcinoma and the B16F10 melanoma, is influenced by the alleles at Hyal-1, in that 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.90.12.5708
更新日期:1993-06-15 00:00:00
abstract::SsrA/SsrB is a primary two-component system that mediates the survival and replication of Salmonella within host cells. When activated, the SsrB response regulator directly promotes the transcription of multiple genes within Salmonella pathogenicity island 2 (SPI-2). As expression of the SsrB protein is promoted by se...
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.1000759107
更新日期:2010-11-23 00:00:00
abstract::The guanidinium group of arginine-166 has been postulated to act as an electrophilic species during phosphorylation of alkaline phosphatase. Its role could be either to stabilize the developing negative charge on the oxygen of the leaving group or the pentacoordinate transition state or to help bind the -PO2-3 group. ...
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.85.12.4276
更新日期:1988-06-01 00:00:00
abstract::Sensory receptor neurons match their dynamic range to ecologically relevant stimulus intensities. How this tuning is achieved is poorly understood in most receptors. The roundworm Caenorhabditis elegans avoids 21% O2 and hypoxia and prefers intermediate O2 concentrations. We show how this O2 preference is sculpted by ...
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.1614596114
更新日期:2017-06-06 00:00:00
abstract::Previous studies implicate the hypothalamic ventromedial nucleus (VMN) in glycemic control. Here, we report that selective inhibition of the subset of VMN neurons that express the transcription factor steroidogenic-factor 1 (VMN(SF1) neurons) blocks recovery from insulin-induced hypoglycemia whereas, conversely, activ...
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.1521160113
更新日期:2016-04-05 00:00:00
abstract::Huntington's disease (HD) is an untreatable neurological disorder caused by selective and progressive degeneration of the caudate nucleus and putamen of the basal ganglia. Although the etiology of HD pathology is not fully understood, the observed loss of neuronal cells is thought to occur primarily through apoptosis....
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.162362299
更新日期:2002-08-06 00:00:00
abstract::We have used the 1.1 kilobases of the 5' upstream region of the platelet factor four (PF4) gene coupled to the prokaryotic beta-galactosidase gene to generate two lines of transgenic mice that express this construct. Studies of blood, bone marrow, spleen, and thymus reveal that platelets are the only circulating blood...
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.88.4.1521
更新日期:1991-02-15 00:00:00
abstract::Queuosine (Q) is a complex tRNA modification widespread in eukaryotes and bacteria that contributes to the efficiency and accuracy of protein synthesis. Eukaryotes are not capable of Q synthesis and rely on salvage of the queuine base (q) as a Q precursor. While many bacteria are capable of Q de novo synthesis, salvag...
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.1909604116
更新日期:2019-09-17 00:00:00
abstract::Guanosine 3':5'-cyclic monophosphate (cGMP) increased 7-fold in rat pineal glands incubated in the presence of l-norepinephrine. This response consisted of two components-one was stereospecific and inhibited by alpha-adrenergic antagonists while the other was not stereospecific and not readily inhibited by antagonists...
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.73.10.3398
更新日期:1976-10-01 00:00:00
abstract::Song syntax, defined as orderly temporal arrangements of acoustic units within a bird song, is a conspicuous feature of the songs of many species of passerine birds. While syntactical features play a role in interspecific song recognition by males of many bird species, syntax variation within species and female respon...
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.85.10.3657
更新日期:1988-05-01 00:00:00
abstract::Memory CD8 T cells provide durable protection against diverse intracellular pathogens and can be broadly segregated into distinct circulating and tissue-resident populations. Paradigmatic studies have demonstrated that circulating memory cells can be further divided into effector memory (Tem) and central memory (Tcm) ...
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.2008571117
更新日期:2020-10-13 00:00:00
abstract::The functional architecture of mammalian visual cortex has been elucidated in impressive detail by experimental work of the past 20-25 years. The origin of many of the salient features of this architecture, however, has remained unexplained. This paper is the first of three (the others will appear in subsequent issues...
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.83.19.7508
更新日期:1986-10-01 00:00:00
abstract::We have previously shown that chronic activation of mitogenic signaling induced by over-expression of c-myc and transforming growth factor-alpha (TGFalpha) transgenes in mouse liver induces a state of oxidative stress. We therefore proposed that increased reactive oxygen species (ROS) generation might be responsible f...
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.040428797
更新日期:2000-02-29 00:00:00
abstract::Physical biochemical techniques are used to establish the structure, subunit stoichiometry, and assembly pathway of the primosome complex of the bacteriophage T4 DNA replication system. Analytical ultracentrifugation and fluorescence anisotropy methods show that the functional T4 primosome consists of six gp41 helicas...
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.1210040109
更新日期:2012-08-21 00:00:00
abstract::Purified fractions of human apotransferrin, monoferric transferrins with iron on the acid-labile binding site and on the acid-stable binding site, and diferric transferrin have been prepared. The iron loading and unloading behavior of these preparations has been examined by isoelectric focusing. Iron release from 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.78.4.2572
更新日期:1981-04-01 00:00:00
abstract::Conflict between groups of individuals is a prevalent feature in human societies. A common theoretical explanation for intergroup conflict is that it provides benefits to individuals within groups in the form of reproduction-enhancing resources, such as food, territory, or mates. However, it is not always the case tha...
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.1810404116
更新日期:2019-07-09 00:00:00
abstract::The induction of heat shock proteins in three species of Leishmania, L. tropica, L. enrietti, and L. donovani is reported. When cultures of promastigotes are shifted from 26 degrees C to 37 degrees C or 40 degrees C, the synthesis of proteins with apparent molecular weights of 88,000, 74,000, and 54,000 is stimulated....
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.82.13.4414
更新日期:1985-07-01 00:00:00
abstract::Protein 4.1R (4.1R) is a multifunctional component of the red cell membrane. It forms a ternary complex with actin and spectrin, which defines the nodal junctions of the membrane-skeletal network, and its attachment to the transmembrane protein glycophorin C creates a bridge between the protein network and the membran...
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.0803225105
更新日期:2008-06-10 00:00:00
abstract::There is currently no consensus on the importance of climate change in Mesoamerican prehistory. Some invoke drought as a causal factor in major cultural transitions, including the abandonment of many sites at 900 CE, while others conclude that cultural factors were more important. This lack of agreement reflects the f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.1405653112
更新日期:2015-02-10 00:00:00