Survival without recovery after mass extinctions.

abstract：:Representational difference analysis was used to search for pathogens in multiple sclerosis brains. We detected a 341-nucleotide fragment that was 99.4% identical to the major DNA binding protein gene of human herpesvirus 6 (HHV-6). Examination of 86 brain specimens by PCR demonstrated that HHV-6 was present in > 70% ...

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

authors： Challoner PB,Smith KT,Parker JD,MacLeod DL,Coulter SN,Rose TM,Schultz ER,Bennett JL,Garber RL,Chang M

更新日期：1995-08-01 00:00:00

abstract：:Enveloped viruses exploit the endomembrane system to enter host cells. Through a cascade of membrane-trafficking events, virus-bearing vesicles fuse with acidic endosomes and/or lysosomes mediated by SNAREs triggering viral fusion. However, the molecular mechanisms underlying this process remain elusive. Here, we foun...

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

authors： Pirooz SD,He S,Zhang T,Zhang X,Zhao Z,Oh S,O'Connell D,Khalilzadeh P,Amini-Bavil-Olyaee S,Farzan M,Liang C

更新日期：2014-02-18 00:00:00

abstract：:Chick calvaria labeled in vitro contain a triple-stranded collagen precursor that contains two pro alpha1 and one pro alpha2 chains. All chains contain cystine and are linked by S-S bonds. Ultracentrifugal analysis was used to measure the relative size of the disulfide-linked units. It is proposed that the S-S links h...

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

authors： Fessler LI,Burgeson RE,Morris NP,Fessler JH

更新日期：1973-10-01 00:00:00

abstract：:A critique is presented of the Lumsden-Wilson theory [Lumsden, C. J. & Wilson, E. O. (1980) Proc. Natl. Acad. Sci. USA 77, 4382-4386] of the transmission of cultural traits. An analysis of the underlying assumptions and the mathematical nature of the theory clarifies its essentially reductionist and determinist qualit...

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

authors： Alper JS,Lange RV

更新日期：1981-06-01 00:00:00

abstract：:C factor, an intercellular signaling protein, is required for aggregation and sporulation of the social bacterium, Myxococcus xanthus. We report that C factor, which normally is associated with the cell surface, provides input to the Frz signal transduction cascade. Elements of this cascade have sequence homology to b...

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

authors： Søgaard-Andersen L,Kaiser D

更新日期：1996-04-02 00:00:00

abstract：:High-quality protein crystals meant for structural analysis by X-ray diffraction have been grown by various methods. The observation of dynamical diffraction in protein crystals is an interesting topic because dynamical diffraction generally occurs in perfect crystals such as Si crystals. However, to our knowledge, th...

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

authors： Suzuki R,Koizumi H,Hirano K,Kumasaka T,Kojima K,Tachibana M

更新日期：2018-04-03 00:00:00

abstract：:In eukaryotes, transfer RNAs (tRNAs) are transcribed in the nucleus yet function in the cytoplasm; thus, tRNA movement within the cell was believed to be unidirectional--from the nucleus to the cytoplasm. It is now known that mature tRNAs also move in a retrograde direction from the cytoplasm to the nucleus via retrog...

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

authors： Kramer EB,Hopper AK

更新日期：2013-12-24 00:00:00

abstract：:The problem of the propagation of conformational changes over long distances or through a closely packed protein is shown to fit a model of a ligand-induced conformational change between two protein states selected by evolution. Moreover, the kinetics of the pathway between these states is also selected so that the en...

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

authors： Yu EW,Koshland DE Jr

更新日期：2001-08-14 00:00:00

abstract：:Campylobacter jejuni has a general N-linked glycosylation pathway (encoded by the pgl gene cluster), which culminates in the transfer of a heptasaccharide: GalNAc-alpha1,4-GalNAc-alpha1,4-(Glcbeta1,3)-GalNAc-alpha1,4-GalNAc-alpha1,4-GalNAc-alpha1,3-Bac [where Bac is bacillosamine (2,4-diacetamido-2,4,6-trideoxyglucose...

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

authors： Glover KJ,Weerapana E,Imperiali B

更新日期：2005-10-04 00:00:00

abstract：:Cryoelectron microscopy and X-ray crystallography have recently been used to generate structural models that likely represent the unliganded closed-channel conformation and the fully liganded open-channel conformation of different members of the nicotinic-receptor superfamily. To characterize the structure of the clos...

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

authors： Gonzalez-Gutierrez G,Cuello LG,Nair SK,Grosman C

更新日期：2013-11-12 00:00:00

abstract：:Breast tumors lacking expression of human epidermal growth factor receptor 2 (HER2) and the estrogen and the progesterone receptors (triple negative; TNBC) are more aggressive than other disease subtypes, and no molecular targeted agents are currently available for their treatment. Because TNBC commonly displays EGF r...

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

authors： Ferraro DA,Gaborit N,Maron R,Cohen-Dvashi H,Porat Z,Pareja F,Lavi S,Lindzen M,Ben-Chetrit N,Sela M,Yarden Y

更新日期：2013-01-29 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 involvement of epigenetic alterations in mediating effects of estrogens on memory is unknown. The present study determined whether histone acetylation and DNA methylation are critical for the potent estrogen 17beta-estradiol (E(2)) to enhance object recognition memory. We show that dorsal hippocampal E(2) infusion...

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

authors： Zhao Z,Fan L,Frick KM

更新日期：2010-03-23 00:00:00

abstract：:Human thioredoxin reductase (TR) contains selenocysteine (Secys) in a redox center [cysteine (Cys)-497,Secys-498] near the C-terminus. The essential role of Secys in TR isolated from HeLa cells was demonstrated by the alkylation studies. Reaction of native NADPH reduced enzyme with bromoacetate at pH 6.5 inhibited enz...

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

authors： Gorlatov SN,Stadtman TC

更新日期：1998-07-21 00:00:00

abstract：:Functionally differentiated chicken macrophages were derived by in vitro differentiation of embryonic yolk sac cells and were characterized by several macrophage-specific cell markers. Uniform, infected, virus-producing cultures were obtained after exposure of these macrophages to avian myoblastosis virus (AMV), avian...

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

authors： Durban EM,Boettiger D

更新日期：1981-06-01 00:00:00

abstract：:Interleukin 2 (IL-2) occupies a central position in the cascade of events involved in the immune response. We were interested in determining whether IL-2 could function as an adjuvant to vaccination, to increase the immune response to vaccine immunogens. Using the National Institutes of Health test for rabies vaccine ...

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

authors： Nunberg JH,Doyle MV,York SM,York CJ

更新日期：1989-06-01 00:00:00

abstract：:Shoot architecture is critical for optimizing plant adaptation and productivity. In contrast with annuals, branching in perennials native to temperate and boreal regions must be coordinated with seasonal growth cycles. How branching is coordinated with seasonal growth is poorly understood. We identified key components...

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

authors： Maurya JP,Miskolczi PC,Mishra S,Singh RK,Bhalerao RP

更新日期：2020-05-26 00:00:00

abstract：:Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face-object associations were scanned during passive rest and during encoding of new related and unre...

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

authors： Schlichting ML,Preston AR

更新日期：2014-11-04 00:00:00

abstract：:The phosphorylation state of the Na,K-ATPase alpha subunit has been examined in 32P-labeled sciatic nerves of control and streptozotocin-treated diabetic rats. Intact nerves were challenged with protein kinase (PK) modulators and alpha-subunit 32P labeling was analyzed after immunoprecipitation. In control nerves, the...

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

authors： Borghini I,Geering K,Gjinovci A,Wollheim CB,Pralong WF

更新日期：1994-06-21 00:00:00

abstract：:Insulin resistance, obesity, diabetes, dyslipidemia, and nonalcoholic fatty liver are components of the metabolic syndrome, a disease complex that is increasing at epidemic rates in westernized countries. Although proinflammatory cytokines have been suggested to contribute to the development of these disorders, the mo...

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

authors： Ueki K,Kondo T,Tseng YH,Kahn CR

更新日期：2004-07-13 00:00:00

abstract：:A near-full-length casbene synthase cDNA clone, pCS7, was isolated by using a partial cDNA clone, pCS4, to probe a lambda gt10 library constructed from poly(A)+ RNA from elicited castor bean seedlings. The cDNA insert had a length of 1983 bases with a polyadenylate tail of 19 bases. Translation of the cDNA sequence re...

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

authors： Mau CJ,West CA

更新日期：1994-08-30 00:00:00

abstract：:The hydroxyproline-containing proteins (hyproproteins) synthesized by cultured human fibroblasts have been partially characterized. The hyproprotein extracted from the cell layer was found to be similar to the collagen extracted from skin in the ratio of hydroxyproline to proline, chain composition, solubility, and re...

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

authors： Layman DL,McGoodwin EB,Martin GR

更新日期：1971-02-01 00:00:00

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：:Perceptual decisions are better when they take uncertainty into account. Uncertainty arises not only from the properties of sensory input but also from cognitive sources, such as different levels of attention. However, it is unknown whether humans appropriately adjust for such cognitive sources of uncertainty during p...

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

authors： Denison RN,Adler WT,Carrasco M,Ma WJ

更新日期：2018-10-23 00:00:00

abstract：:Recent technical advances allow detection of several hundred volatile organic compounds (VOCs) in human exhaled air, many of which reflect unidentified endogenous pathways. Our group has previously estimated plasma glucose levels in healthy adults during a standard oral glucose tolerance test via exhaled VOC analysis....

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

authors： Novak BJ,Blake DR,Meinardi S,Rowland FS,Pontello A,Cooper DM,Galassetti PR

更新日期：2007-10-02 00:00:00

abstract：:Early conformational events during folding of acyl-CoA binding protein (ACBP), an 86-residue alpha-helical protein, were explored by using a continuous-flow mixing apparatus with a dead time of 70 micros to measure changes in intrinsic tryptophan fluorescence and tryptophan-dansyl fluorescence energy transfer. Althoug...

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

authors： Teilum K,Maki K,Kragelund BB,Poulsen FM,Roder H

更新日期：2002-07-23 00:00:00

abstract：:Gene delivery to the central nervous system is central to the development of gene therapy for neurological diseases. We developed a baculovirus-derived vector, the Bac-CMV-GFP vector, containing a reporter gene encoding for the green fluorescent protein (GFP) under the control of the cytomegalovirus (CMV) promoter. Tw...

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

authors： Sarkis C,Serguera C,Petres S,Buchet D,Ridet JL,Edelman L,Mallet J

更新日期：2000-12-19 00:00:00

abstract：:Techniques of fluorescence and ion microscopies were combined to study the free [Ca2+] and total Ca in NIH 3T3 fibroblast and L6 rat myoblast cells. Free Ca2+ measurements with the Ca2+ indicator fura-2 and digital imaging reveal an inhomogeneous distribution of free cytoplasmic Ca2+ in both cell lines. Fura-2 also re...

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

authors： Chandra S,Gross D,Ling YC,Morrison GH

更新日期：1989-03-01 00:00:00

abstract：:Documented cases of convergent molecular evolution due to selection are fairly unusual, and examples to date have involved only a few amino acid positions. However, because convergence mimics shared ancestry and is not accommodated by current phylogenetic methods, it can strongly mislead phylogenetic inference when it...

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

authors： Castoe TA,de Koning AP,Kim HM,Gu W,Noonan BP,Naylor G,Jiang ZJ,Parkinson CL,Pollock DD

更新日期：2009-06-02 00:00:00

abstract：:A sensitive, labor-saving, and easily automatable nonradioactive procedure named APEX-FCS (amplified probe extension detected by fluorescence correlation spectroscopy) has been established to detect specific in vitro amplification of pathogen genomic sequences. As an example, Mycobacterium tuberculosis genomic DNA was...

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

authors： Walter NG,Schwille P,Eigen M

更新日期：1996-11-12 00:00:00