Directional selection is the primary cause of phenotypic diversification.

abstract：:Proteins, nucleic acids, and fluorescein-conjugated antibody are shown to be identifidable in situ via the fluorescence excited by the focused electron beam of a canning electron microscope. A molecular species is identified by its characteristic fluorescence spectrum and by a characteristic alteration of the spectrum...

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

authors： Hough PV,McKinney WR,Ledbeter MC,Pollack RE,Moos HW

更新日期：1976-02-01 00:00:00

abstract：:In this report we provide evidence that neuronal nicotinic acetylcholine receptors (nAChRs) are present on hippocampal astrocytes and their activation produces rapid currents and calcium transients. Our data indicate that these responses obtained from astrocytes are primarily mediated by an AChR subtype that is functi...

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

authors： Sharma G,Vijayaraghavan S

更新日期：2001-03-27 00:00:00

abstract：:A series of monoclonal antibodies was used to define three discrete stages of human intrathymic T-cell differentiation. The earliest stage was confined to <10% of thymocytes, which were.reactive with both OKT9 and OKT10. Subsequently, approximately 70% of human thymocytes acquired a thymocyte-restricted antigen, OKT6,...

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

authors： Reinherz EL,Kung PC,Goldstein G,Levey RH,Schlossman SF

更新日期：1980-03-01 00:00:00

abstract：:The sequences of large insert clones containing genomic DNA that is orthologous to the maize adh1 region were obtained for sorghum, rice, and the adh1-homoeologous region of maize, a remnant of the tetraploid history of the Zea lineage. By using all four genomes, it was possible to describe the nature, timing, and lin...

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

authors： Ilic K,SanMiguel PJ,Bennetzen JL

更新日期：2003-10-14 00:00:00

abstract：:Turkey erythrocyte membranes showed specific binding of [(3)H]epinephrine. The concentration of hormone required for half-maximal binding (30 muM) was the same as that required for half-maximal activation of the adenylate cyclase located in the same membrane preparation. The binding reaction at 37 degrees C reached co...

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

authors： Schramm M,Feinstein H,Naim E,Lang E,Lasser M

更新日期：1972-02-01 00:00:00

abstract：:Paired oxygen-isotopic analyses of abiotic carbonate and benthic-ostracode shells from lake sediments provide a continuous quantitative record of growing-season temperature for the past 2000 years in the northwestern foothills of the Alaska Range. This record reveals three time intervals of comparable warmth: anno Dom...

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

authors： Hu FS,Ito E,Brown TA,Curry BB,Engstrom DR

更新日期：2001-09-11 00:00:00

abstract：:Despite high predation pressure, planktonic copepods remain one of the most abundant groups on the planet. Their escape response provides one of most effective mechanisms to maximize evolutionary fitness. Owing to their small size (100 µm) compared with their predators (>1 mm), increasing viscosity is believed to have...

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

authors： Gemmell BJ,Sheng J,Buskey EJ

更新日期：2013-03-19 00:00:00

abstract：:Many ion channels exhibit a slow stochastic switching between distinct modes of gating activity. This feature of channel behavior has pronounced implications for the dynamics of ionic currents and the signaling pathways that they regulate. A canonical example is the inositol 1,4,5-trisphosphate receptor (IP3R) channel...

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

authors： Bicknell BA,Goodhill GJ

更新日期：2016-09-06 00:00:00

abstract：:Tetrodotoxin was infused into the suprachiasmatic nuclei of unanesthetized and unrestrained rats continuously for 14 days. The internal timekeeping mechanism of the circadian pacemaker in the nuclei continued to oscillate unaffected by this treatment, although the toxin reversibly blocked function of both the input pa...

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

authors： Schwartz WJ,Gross RA,Morton MT

更新日期：1987-03-01 00:00:00

abstract：:The Ah receptor (AHR) is a basic helix-loop-helix protein that mediates the effects of 2,3,7,8-tetrachloro-dibenzo-p-dioxin. In this report, we describe a rabbit reticulocyte system that allows functional expression of both the AHR and its dimeric partner, the AHR nuclear translocator protein (ARNT). By using this in ...

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

authors： Dolwick KM,Swanson HI,Bradfield CA

更新日期：1993-09-15 00:00:00

abstract：:Differentiation-inducing factor 1 [DIF-1; 1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl)-hexan-1-one] induces stalk cell differentiation during Dictyostelium development. It is present as a gradient in the multicellular slug, its lowest concentration being in the anterior. Here we demonstrate the existence of a locali...

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

authors： Kay RR,Large S,Traynor D,Nayler O

更新日期：1993-01-15 00:00:00

abstract：:The lack of genetic means has been a serious limitation in studying mosquito immunity. We generated Relish-mediated immune deficiency (RMID) by transforming Aedes aegypti with the Delta Rel transgene driven by the vitellogenin (Vg) promoter using the pBac[3xP3-EGFP, afm] vector. A stable transformed line had a single ...

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

authors： Shin SW,Kokoza V,Lobkov I,Raikhel AS

更新日期：2003-03-04 00:00:00

abstract：:"Head-to-head" terpene synthases catalyze the first committed steps in sterol and carotenoid biosynthesis: the condensation of two isoprenoid diphosphates to form cyclopropylcarbinyl diphosphates, followed by ring opening. Here, we report the structures of Staphylococcus aureus dehydrosqualene synthase (CrtM) complexe...

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

authors： Lin FY,Liu CI,Liu YL,Zhang Y,Wang K,Jeng WY,Ko TP,Cao R,Wang AH,Oldfield E

更新日期：2010-12-14 00:00:00

abstract：:A model of the photochemical apparatus of photosynthesis, presented previously in a tripartite format, is used in a bipartite format to analyze energy transfer between photosystem II units. The model is used to develop analytical expressions for the photochemical properties of chloroplasts that include a term for the ...

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

authors： Butler WL

更新日期：1980-08-01 00:00:00

abstract：:The endothelins (ETs) form a group of three vasoactive peptides (ET-1, ET-2, and ET-3) for which two types of cellular receptors have been identified, types A and B ET receptors (ETA and ETB receptors, respectively). To address possible targets for ETs within the liver, we isolated the four principal liver cell popula...

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

authors： Housset C,Rockey DC,Bissell DM

更新日期：1993-10-15 00:00:00

abstract：:Translation of injected mRNA in oocytes of Xenopus laevis has been used as a highly sensitive and quantitative assay for interferon mRNA. Injection into oocytes of polyadenylylated RNA extracted from poly(I).poly(C)-induced human diploid fibroblasts (FS-4) leads to the synthesis of biologically active human fibroblast...

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

authors： Sehgal PB,Dobberstein B,Tamm I

更新日期：1977-08-01 00:00:00

abstract：:The 20S proteasome core particle (20S CP) plays an integral role in cellular homeostasis by degrading proteins no longer required for function. The process is, in part, controlled via gating residues localized to the ends of the heptameric barrel-like CP structure that occlude substrate entry pores, preventing unregul...

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

authors： Huang R,Pérez F,Kay LE

更新日期：2017-11-14 00:00:00

abstract：:The Cercospora nicotianae SOR1 (singlet oxygen resistance) gene was identified previously as a gene involved in resistance of this fungus to singlet-oxygen-generating phototoxins. Although homologues to SOR1 occur in organisms in four kingdoms and encode one of the most highly conserved proteins yet identified, the pr...

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

authors： Ehrenshaft M,Bilski P,Li MY,Chignell CF,Daub ME

更新日期：1999-08-03 00:00:00

abstract：:In many plant species only a small proportion of buds yield branches. Both the timing and extent of bud activation are tightly regulated to produce specific branching architectures. For example, the primary shoot apex can inhibit the activation of lateral buds. This process is termed apical dominance and is dependent ...

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

authors： Prusinkiewicz P,Crawford S,Smith RS,Ljung K,Bennett T,Ongaro V,Leyser O

更新日期：2009-10-13 00:00:00

abstract：:c-Jun transcriptional activity is augmented by expression of oncogenic Ras and Raf proteins. This study demonstrates a direct correlation between Ras transforming activity and c-Jun activation, supporting an important role for c-Jun in transformation by Ras. Since we observed that Ras activated c-Jun transcriptional a...

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

authors： Westwick JK,Cox AD,Der CJ,Cobb MH,Hibi M,Karin M,Brenner DA

更新日期：1994-06-21 00:00:00

abstract：:Like protein enzymes, RNA enzymes (ribozymes) provide specific binding sites for their substrates. We now show that equilibrium dissociation constants for complexes between the Tetrahymena ribozyme and its RNA substrates and products can be directly measured by electrophoresis in polyacrylamide gels containing divalen...

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

authors： Pyle AM,McSwiggen JA,Cech TR

更新日期：1990-11-01 00:00:00

abstract：:This paper presents insights and action proposals to better harness technological innovation for sustainable development. We begin with three key insights from scholarship and practice. First, technological innovation processes do not follow a set sequence but rather emerge from complex adaptive systems involving many...

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

authors： Anadon LD,Chan G,Harley AG,Matus K,Moon S,Murthy SL,Clark WC

更新日期：2016-08-30 00:00:00

abstract：:Human fibroblast cells treated with a combination of inhibitors of protein and RNA synthesis [cycloheximide and actinomycin D as used to superinduce interferon beta (IFN-beta)] secrete two proteins with molecular masses of 22000 and 27000 kilodaltons (called 22-kDal and 27-kDal) that are precipitable with an antiserum...

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

authors： Content J,De Wit L,Pierard D,Derynck R,De Clercq E,Fiers W

更新日期：1982-05-01 00:00:00

abstract：:Receptor tyrosine kinases (RTKs) are a class of cell surface receptors that, upon ligand binding, stimulate a variety of critical cellular functions. The orphan receptor anaplastic lymphoma kinase (ALK) is one of very few RTKs that remain without a firmly established protein ligand. Here we present a novel cytokine, F...

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

authors： Reshetnyak AV,Murray PB,Shi X,Mo ES,Mohanty J,Tome F,Bai H,Gunel M,Lax I,Schlessinger J

更新日期：2015-12-29 00:00:00

abstract：:The emergence of the nematic electronic state that breaks rotational symmetry is one of the most fascinating properties of the iron-based superconductors, and has relevance to cuprates as well. FeSe has a unique ground state in which superconductivity coexists with a nematic order without long-range magnetic ordering,...

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

authors： Sato Y,Kasahara S,Taniguchi T,Xing X,Kasahara Y,Tokiwa Y,Yamakawa Y,Kontani H,Shibauchi T,Matsuda Y

更新日期：2018-02-06 00:00:00

abstract：:Completely parthenogenetic Trichogramma wasps can be rendered permanently bisexual by treatment with three different antibiotics or high temperatures. The evidence strongly suggests that maternally inherited microorganisms cause parthenogenesis in these wasps. Theories predict female-biased sex ratio in offspring unde...

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

authors： Stouthamer R,Luck RF,Hamilton WD

更新日期：1990-04-01 00:00:00

abstract：:By optically probing with a focused, low-power laser beam, we measured the spontaneous deflection fluctuations of the sensory hair bundles on frog saccular hair cells with a sensitivity of about 1 pm/square root of Hz. The preparation was illuminated by two orthogonally polarized laser beams separated by only about 0....

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

authors： Denk W,Webb WW,Hudspeth AJ

更新日期：1989-07-01 00:00:00

abstract：:The phosphoprotein (NS) of vesicular stomatitis virus is an indispensable subunit of the virion-associated RNA polymerase (L). NS consists of a highly acidic NH2-terminal domain and a basic COOH-terminal domain. Unlike the latter, the amino acid sequences of the NH2-terminal regions are highly dissimilar among differe...

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

authors： Chattopadhyay D,Banerjee AK

更新日期：1988-11-01 00:00:00

abstract：:We have shown that rat glioma tumors contain a protein that crossreacts with antibody against mouse 2.5S nerve growth factor prepared in rabbit in microcomplement fixation assays and has analogous isoelectric points to all the hybrids of 2.5S nerve growth factor (a dimer). Partially purified protein preparations from ...

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

authors： Longo AM,Penhoet EE

更新日期：1974-06-01 00:00:00

abstract：:The mRNA for organic anion transport protein (oatp) was previously shown to be present in abundance in liver and kidney, and in small amounts in brain. Data obtained from experiments with reverse transcriptase-PCR techniques and in situ hybridization analysis showed that the oatp mRNA is present within the brain, loca...

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

authors： Angeletti RH,Novikoff PM,Juvvadi SR,Fritschy JM,Meier PJ,Wolkoff AW

更新日期：1997-01-07 00:00:00