Mammary number and litter size in Rodentia: The "one-half rule".

abstract：:We have developed an approach for deriving and characterizing antigen-receptor (CD3/Ti) signal-transduction mutants. This strategy combines receptor-mediated growth inhibition and fluorescence-activated cell sorting with the Ca2+-indicator indo-1. Despite the expression of structurally normal CD3/Ti complexes, one suc...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Goldsmith MA,Weiss A

更新日期：1987-10-01 00:00:00

abstract：:In organisms possessing a dispersal phase the processes of mating, competition, feeding, and predation are often carried out within "trait-groups," defined as populations enclosed in areas smaller than the boundaries of the deme. A simple model shows that this can lead to the selection of "altruistic" traits that favo...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wilson DS

更新日期：1975-01-01 00:00:00

abstract：:Glucose entry, as measured by 5-min uptake into the acid-soluble fraction, is enhanced 15-30 times by long-term (12-24 hr) hexose starvation of chick fibroblasts. The rate of galactose accumulation in the cells increases only 5 times under the same conditions of starvation. Several carbon and energy sources that were ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Martineau R,Kohlbacher M,Shaw SN,Amos H

更新日期：1972-11-01 00:00:00

abstract：:Recent studies have shown that the genes of the gibberellin (GA) biosynthesis pathway in the fungus Gibberella fujikuroi are organized in a cluster of at least seven genes. P450-1 is one of four cytochrome P450 monooxygenase genes in this cluster. Disruption of the P450-1 gene in the GA-producing wild-type strain IMI ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Rojas MC,Hedden P,Gaskin P,Tudzynski B

更新日期：2001-05-08 00:00:00

abstract：:Polyketides represent an extremely diverse class of secondary metabolites often explored for their bioactive traits. These molecules are also attractive building blocks for chemical catalysis and polymerization. However, the use of polyketides in larger scale chemistry applications is stymied by limited titers and yie...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Markham KA,Palmer CM,Chwatko M,Wagner JM,Murray C,Vazquez S,Swaminathan A,Chakravarty I,Lynd NA,Alper HS

更新日期：2018-02-27 00:00:00

abstract：:The recent cloning of a second member of the nerve growth factor family, brain-derived neurotrophic factor (BDNF), has prompted investigation into the cells that express this factor's mRNA and protein. In the present study, antibodies raised against unique peptide sequences within the porcine BDNF protein detect BDNF-...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wetmore C,Cao YH,Pettersson RF,Olson L

更新日期：1991-11-01 00:00:00

abstract：:To test the hypothesis that periodic signals and chemotaxis direct later morphogenesis in Dictyostelium discoideum, we investigated cell behavior and cell movement in slugs. Trails of neutral red-stained prestalk and anterior-like cells were recorded by high-resolution digital image processing. Neutral red-stained ant...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Siegert F,Weijer CJ

更新日期：1992-07-15 00:00:00

abstract：:For the emergence of early life, the formation of biopolymers such as RNA is essential. However, the addition of nucleotide monomers to existing oligonucleotides requires millimolar concentrations. Even in such optimistic settings, no polymerization of RNA longer than about 20 bases could be demonstrated. How then cou...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Mast CB,Schink S,Gerland U,Braun D

更新日期：2013-05-14 00:00:00

abstract：:In the plant Nicotiana plumbaginifolia, manganese superoxide dismutase (MnSOD) is synthesized in the cytoplasm as a preprotein and is subsequently translocated to the mitochondrial matrix with corresponding cleavage of an NH2-terminal leader sequence. To determine whether the plant enzyme could replace the endogenous ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Bowler C,Alliotte T,Van den Bulcke M,Bauw G,Vandekerckhove J,Van Montagu M,Inzé D

更新日期：1989-05-01 00:00:00

abstract：:Targeting neuroendocrine tumors expressing somatostatin receptor subtypes (sst) with radiolabeled somatostatin agonists is an established diagnostic and therapeutic approach in oncology. While agonists readily internalize into tumor cells, permitting accumulation of radioactivity, radiolabeled antagonists do not, and ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Ginj M,Zhang H,Waser B,Cescato R,Wild D,Wang X,Erchegyi J,Rivier J,Mäcke HR,Reubi JC

更新日期：2006-10-31 00:00:00

abstract：:Duplexes constituted by closed or open RNA circles paired to single-stranded oligonucleotides terminating with 3'-CCAOH form resected pseudoknots that are substrates of yeast histidyl-tRNA synthetase. Design of this RNA fold is linked to the mimicry of the pseudoknotted amino acid accepting branch of the tRNA-like dom...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Felden B,Giegé R

更新日期：1998-09-01 00:00:00

abstract：:Nonribosomal peptide synthetases (NRPSs) and polyketide synthases are large, multidomain enzymes that biosynthesize a number of pharmaceutically important natural products. The recognition of biosynthetic intermediates, displayed via covalent attachment to carrier proteins, by catalytic domains is critical for NRPS an...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Lai JR,Fischbach MA,Liu DR,Walsh CT

更新日期：2006-04-04 00:00:00

abstract：:Ca2+/calmodulin-dependent protein kinase enriched in cerebellar granule cells (CaM kinase Gr) is a neuronal calmodulin-dependent protein kinase whose purification and partial cloning from rat brain has been described. A combination of the polymerase chain reaction and cDNA library screening was used to determine the D...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Ohmstede CA,Bland MM,Merrill BM,Sahyoun N

更新日期：1991-07-01 00:00:00

abstract：:The class II transactivator (CIITA) is the master integrator of expression of MHC class II genes. It interacts with variety of basal transcription factors to initiate and elongate transcription of these genes. Among others, it recruits positive transcription elongation factor b (P-TEFb) to MHC class II promoters. In c...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Kohoutek J,Blazek D,Peterlin BM

更新日期：2006-11-14 00:00:00

abstract：:Although neurotrophins are primarily associated with long-term effects on neuronal survival and differentiation, recent studies have shown that acute changes in synaptic transmission can also be produced. In the hippocampus, an area critically involved in learning and memory, we have found that brain-derived neurotrop...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Levine ES,Dreyfus CF,Black IB,Plummer MR

更新日期：1995-08-15 00:00:00

abstract：:Chromosomal RNA, which is a component of the chromosomes of higher organisms, and whose participation is required for sequence-specific interaction of chromosomal proteins with chromosomal DNA, occurs in chromosomes bound to DNA. We have found that the DNA sequences to which chromosomal RNA binds are repetitive ones. ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Sivolap YM,Bonner J

更新日期：1971-02-01 00:00:00

abstract：:Chronic microbial infections are associated with fibrotic and inflammatory reactions known as granulomas showing similarities to wound-healing and tissue repair processes. We have previously mapped three leishmaniasis susceptibility loci, designated lmr1, -2, and -3, which exert their effect independently of T cell im...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Sakthianandeswaren A,Elso CM,Simpson K,Curtis JM,Kumar B,Speed TP,Handman E,Foote SJ

更新日期：2005-10-25 00:00:00

abstract：:Protein tyrosine phosphorylation in purified synaptic vesicles from rat forebrain has been studied in the presence of Mn2+ and orthovanadate. High levels of endogenous protein tyrosine phosphorylation were observed. Four major phosphoproteins, with apparent molecular masses of 105, 94, 38, and 30 kDa, were shown to co...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Pang DT,Wang JK,Valtorta F,Benfenati F,Greengard P

更新日期：1988-02-01 00:00:00

abstract：:The POT1 (protection of telomeres 1) protein binds the ssDNA overhangs at the ends of chromosomes in diverse eukaryotes. POT1 is essential for chromosome end-protection, as best demonstrated in fission yeast. In human cells, hPOT1 is also involved in telomere-length regulation. We now show that telomeric oligonucleoti...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Zaug AJ,Podell ER,Cech TR

更新日期：2005-08-02 00:00:00

abstract：:The ASCAPE agent-based modeling environment greatly eases the task of designing and investigating agent-based models. However, effective design can still require a relatively deep knowledge of programming and agent-based modeling. This issue has almost certainly slowed the adoption of agent-based modeling approaches t...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Inchiosa ME,Parker MT

更新日期：2002-05-14 00:00:00

abstract：:Human C5a, a complement-derived anaphylatoxin, is a potent mediator of human leukocyte chemotaxis. Using a homogeneous preparation of C5a that was 125I-labeled, we have demonstrated the presence of a specific cellular receptor for this glycoprotein on intact human polymorphonuclear leukocytes. Cellular uptake of the r...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Chenoweth DE,Hugli TE

更新日期：1978-08-01 00:00:00

abstract：:CD4(+) T cells are generally regarded as helpers and regulators of the immune response. Although cytolytic CD4(+) T cells have been described, whether those generated during the course of a viral infection play a role in virus control remains unknown. Here we show that during acute infection with ectromelia virus, the...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Fang M,Siciliano NA,Hersperger AR,Roscoe F,Hu A,Ma X,Shamsedeen AR,Eisenlohr LC,Sigal LJ

更新日期：2012-06-19 00:00:00

abstract：:p-Coumaric acid is the precursor of phenylpropanoids, which are plant secondary metabolites that are beneficial to human health. Tyrosine ammonia lyase catalyzes the production of p-coumaric acid from tyrosine. Because of their photosynthetic ability and biosynthetic versatility, cyanobacteria are promising candidates...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Xue Y,Zhang Y,Cheng D,Daddy S,He Q

更新日期：2014-07-01 00:00:00

abstract：:The coexistence of two phylogenetically distinct symbiont species within a single cell, a condition not previously known in any metazoan, is demonstrated in the gills of a Mid-Atlantic Ridge hydrothermal vent mussel (family Mytilidae). Large and small symbiont morphotypes within the gill bacteriocytes are shown to be ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Distel DL,Lee HK,Cavanaugh CM

更新日期：1995-10-10 00:00:00

abstract：:The 5' flanking sequences and the intron of the mouse Hoxa-7 gene were searched for regulatory elements that can function in Drosophila. Only the intron is able to activate a lacZ fusion gene in various tissues of Drosophila embryos. This enhancer function requires a cluster of three homeodomain binding sites (HB1-ele...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Haerry TE,Gehring WJ

更新日期：1996-11-26 00:00:00

abstract：:Protein functions require conformational motions. We show here that the dominant conformational motions are slaved by the hydration shell and the bulk solvent. The protein contributes the structure necessary for function. We formulate a model that is based on experiments, insights from the physics of glass-forming liq...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Frauenfelder H,Chen G,Berendzen J,Fenimore PW,Jansson H,McMahon BH,Stroe IR,Swenson J,Young RD

更新日期：2009-03-31 00:00:00

abstract：:Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species' organismal body temperature. This simple change is unlikely because a...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Gilman SE,Wethey DS,Helmuth B

更新日期：2006-06-20 00:00:00

abstract：:P2X receptors for ATP have a wide range of physiological roles and comprise a structurally distinct family of ligand-gated trimeric ion channels. The crystal structure of a P2X4 receptor, in combination with mutagenesis studies, has provided a model of the intersubunit ATP-binding sites and identified an extracellular...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Roberts JA,Allsopp RC,El Ajouz S,Vial C,Schmid R,Young MT,Evans RJ

更新日期：2012-03-20 00:00:00

abstract：:MicroRNAs (miRNAs) are small (approximately 21 nt), noncoding RNAs that negatively regulate target mRNAs at the posttranscriptional level that are involved in development. In plants, virus-induced disease symptoms often result in developmental abnormalities resembling perturbation of miRNA-mediated function. Here, we ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Chellappan P,Vanitharani R,Fauquet CM

更新日期：2005-07-19 00:00:00

abstract：:A general theory of the structure of complexes of the transition metals is developed on the basis of the enneacovalence of the metals and the requirements of the electroneutrality principle. An extra orbital may be provided through the small but not negligible amount of f and g character of spd bond orbitals, and an e...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Pauling L

更新日期：1977-12-01 00:00:00