The specific direct interaction of helper T cells and antigen-presenting B cells.

abstract：:We give a functional generalization of fractal scaling laws applied to response problems as well as to probability distributions. We consider excitations and responses, which are functions of a given state vector. Based on scaling arguments, we derive a general nonlinear response functional scaling law, which expresse...

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

authors： Vlad MO,Morán F,Popa VT,Szedlacsek SE,Ross J

更新日期：2007-03-20 00:00:00

abstract：:A close study of the metabolic regulation of hexose transport in a hamster fibroblast mutant, highly defective in the enzyme phosphoglucose isomerase (PGI mutant), reveals the requirement for at least three vectors for transport regulation. The downward regulation of the hexose transport system, called the "transport ...

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

authors： Kalckar HM,Ullrey DB

更新日期：1984-02-01 00:00:00

abstract：:FtsEX is a bacterial ABC transporter that regulates the activity of periplasmic peptidoglycan amidases via its interaction with the murein hydrolase activator, EnvC. In Escherichia coli, FtsEX is required to separate daughter cells after cell division and for viability in low-osmolarity media. Both the ATPase activity...

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

authors： Cook J,Baverstock TC,McAndrew MBL,Stansfeld PJ,Roper DI,Crow A

更新日期：2020-11-10 00:00:00

abstract：:Kinetic partitioning is predicted to be a general mechanism for proteins to fold into their well defined native three-dimensional structure from unfolded states following multiple folding pathways. However, experimental evidence supporting this mechanism is still limited. By using single-molecule atomic force microsco...

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

authors： Peng Q,Li H

更新日期：2008-02-12 00:00:00

abstract：:The study of gene family members has been aided by the isolation of related genes on the basis of DNA homology. We have adapted the polymerase chain reaction to screen animal genomes very rapidly and reliably for likely gene family members. Using conserved amino acid sequences to design degenerate oligonucleotide prim...

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

authors： Kamb A,Weir M,Rudy B,Varmus H,Kenyon C

更新日期：1989-06-01 00:00:00

abstract：:Although common in birds, social monogamy, or pair-living, is rare among mammals because internal gestation and lactation in mammals makes it advantageous for males to seek additional mating opportunities. A number of hypotheses have been proposed to explain the evolution of social monogamy among mammals: as a male ma...

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

authors： Opie C,Atkinson QD,Dunbar RI,Shultz S

更新日期：2013-08-13 00:00:00

abstract：:The formation of a fracture network is a key process for many geophysical and industrial practices from energy resource recovery to induced seismic management. We focus on the initial stage of a fracture network formation using experiments on the symmetric coalescence of two equal coplanar, fluid-driven, penny-shaped ...

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

authors： O'Keeffe NJ,Zheng Z,Huppert HE,Linden PF

更新日期：2018-10-09 00:00:00

abstract：:Most, but not all, aged rats exhibit a profound deficit in spatial memory when tested in a radial maze--a task known to depend on the integrity of the hippocampal formation. In this study, animals were divided into three groups based on their spatial memory capacity: young adult rats with good memory, aged rats with i...

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

authors： Geinisman Y,de Toledo-Morrell L,Morrell F

更新日期：1986-05-01 00:00:00

abstract：:Climate change affects organisms worldwide with profound ecological and evolutionary consequences, often increasing population extinction risk. Climatic factors can increase the strength, variability, or direction of natural selection on phenotypic traits, potentially driving adaptive evolution. Phenotypic plasticity ...

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

authors： Svensson EI,Gomez-Llano M,Waller JT

更新日期：2020-11-24 00:00:00

abstract：:Multiple drug resistance of tumor cells is a common problem in cancer therapy. We have demonstrated that membrane vesicles from highly multidrug-resistant human KB carcinoma cell lines exhibit increased specific and saturable binding of vinblastine. To identify the molecules that bind vinblastine, membrane vesicles fr...

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

authors： Cornwell MM,Safa AR,Felsted RL,Gottesman MM,Pastan I

更新日期：1986-06-01 00:00:00

abstract：:Mutations in BRCA1 are present in 45% of families that segregate with susceptibility for breast cancer and in 80-90% of families with both breast and ovarian cancer. Here we report that BRCA1 stimulates artificial and genomic promoter constructs containing p53-responsive elements. This activity of BRCA1 depends on the...

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

authors： Ouchi T,Monteiro AN,August A,Aaronson SA,Hanafusa H

更新日期：1998-03-03 00:00:00

abstract：:The recently discovered potato tuber (Solanum tuberosum) alpha-glucan, water dikinase (GWD) (formerly known as R1) catalyzes the phosphorylation of starch by a dikinase-type reaction mechanism in which the beta-phosphate of ATP is transferred to either the C-6 or the C-3 position of the glucosyl residue of starch. In ...

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

authors： Mikkelsen R,Mutenda KE,Mant A,Schürmann P,Blennow A

更新日期：2005-02-01 00:00:00

abstract：:The common acute lymphoblastic leukemia antigen (CALLA) is a 749-amino acid type II integral membrane protein that has been identified recently as the neutral endopeptidase 24.11 [NEP (EC 3.4.24.11)]. Herein, we characterize the organization of the human CALLA/NEP gene and show that it spans more than 80 kilobases (kb...

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

authors： D'Adamio L,Shipp MA,Masteller EL,Reinherz EL

更新日期：1989-09-01 00:00:00

abstract：:A codon-optimized mouse LINE-1 element, ORFeus, exhibits dramatically higher retrotransposition frequencies compared with its native long interspersed element 1 counterpart. To establish a retrotransposon-mediated mouse model with regulatable and potent mutagenic capabilities, we generated a tetracycline (tet)-regulat...

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

authors： O'Donnell KA,An W,Schrum CT,Wheelan SJ,Boeke JD

更新日期：2013-07-16 00:00:00

abstract：:A method is presented for starting from a very-low-energy high-dimensional conformation and obtaining a low-energy three-dimensional structure by gradual contraction of the dimensionality. The contraction in dimensionality is achieved by use of Cayley-Menger determinants, of which a simplified form is derived here. Pr...

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

authors： Purisima EO,Scheraga HA

更新日期：1986-05-01 00:00:00

abstract：:Whereas the importance of macrophages in chronic inflammatory diseases is well recognized, there is an increasing awareness that neutrophils may also play an important role. In addition to the well-documented heterogeneity of macrophage phenotypes and functions, neutrophils also show remarkable phenotypic diversity am...

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

authors： Weiss M,Byrne AJ,Blazek K,Saliba DG,Pease JE,Perocheau D,Feldmann M,Udalova IA

更新日期：2015-09-01 00:00:00

abstract：:Prochlorococcus is an abundant marine cyanobacterium that grows rapidly in the environment and contributes significantly to global primary production. This cyanobacterium coexists with many cyanophages in the oceans, likely aided by resistance to numerous co-occurring phages. Spontaneous resistance occurs frequently i...

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

authors： Avrani S,Lindell D

更新日期：2015-04-28 00:00:00

abstract：:Oxidative stress is a ubiquitous threat to all aerobic organisms and has been implicated in numerous pathological conditions such as cancer. Here we demonstrate a pivotal role for E2F1, a cell cycle regulatory transcription factor, in cell tolerance of oxidative stress. Cells lacking E2F1 are hypersensitive to oxidati...

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

authors： Graves JD,Lee YJ,Liu K,Li G,Lin FT,Lin WC

更新日期：2020-06-30 00:00:00

abstract：:A pentapeptide open reading frame equipped with a canonical ribosome-binding site is present in the Escherichia coli 23S rRNA. Overexpression of 23S rRNA fragments containing the mini-gene renders cells resistant to the ribosome-inhibiting antibiotic erythromycin. Mutations that change either the initiator or stop cod...

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

authors： Tenson T,DeBlasio A,Mankin A

更新日期：1996-05-28 00:00:00

abstract：:A monoclonal antibody was produced to human peripheral blood T cells. This hybridoma antibody, termed OKT4, was reactive by indirect immunofluorescence with only 55-60% of the peripheral blood T cell population (OKT4+) and unreactive with normal B cells, null cells, and macrophages. The OKT4- T cell population contain...

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

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

更新日期：1979-08-01 00:00:00

abstract：:The spleen is the lymphoid organ that induces immune responses toward blood-borne pathogens. Specialized macrophages in the splenic marginal zone are strategically positioned to phagocytose pathogens and cell debris, but are not known to play a role in the activation of T-cell responses. Here we demonstrate that splen...

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

authors： Backer R,Schwandt T,Greuter M,Oosting M,Jüngerkes F,Tüting T,Boon L,O'Toole T,Kraal G,Limmer A,den Haan JM

更新日期：2010-01-05 00:00:00

abstract：:HLA class II gene polymorphism was investigated in 100 patients with clinically definite multiple sclerosis (MS) by restriction fragment length polymorphism analysis of Taq I-digested DNA using DRB, DQA, and DQB cDNA probes. Twenty-six patients had primarily chronic progressive MS and 74 had relapsing/remitting MS. Th...

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

authors： Olerup O,Hillert J,Fredrikson S,Olsson T,Kam-Hansen S,Möller E,Carlsson B,Wallin J

更新日期：1989-09-01 00:00:00

abstract：:Bacteriophage lambda integrates into the chromosome of its Escherichia coli host by means of a site-specific recombination between a locus on the phage chromosome (phage att site) and a locus on the bacterial chromosome (bacterial att site). The nucleotide sequence of four lambda att sites altered in site-specific rec...

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

authors： Hoess RH,Landy A

更新日期：1978-11-01 00:00:00

abstract：:Many bacteria use acyl homoserine lactone signals to monitor cell density in a type of gene regulation termed quorum sensing and response. Synthesis of these signals is directed by homologs of the luxi gene of Vibrio fischeri. This communication resolves two critical issues concerning the synthesis of the V. fischeri ...

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

authors： Schaefer AL,Val DL,Hanzelka BL,Cronan JE Jr,Greenberg EP

更新日期：1996-09-03 00:00:00

abstract：:A method is presented for detection of lysosomal hydrolase activity in situ in colonies of Chinese hamster ovary cells. This method was used to screen for mutants deficient in lysosomal alpha-mannosidase. Mutagenized cells were replicated onto filter papers [Esko, J. D. & Raetz, C. R. H. (1978) Proc. Natl. Acad. Sci. ...

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

authors： Robbins AR

更新日期：1979-04-01 00:00:00

abstract：:Clinical and experimental observations indicate a role for VEGF secreted by the retinal pigment epithelium (RPE) in the maintenance of the choriocapillaris (CC). VEGF in mice is produced as three isoforms, VEGF120, VEGF164, and VEGF188, that differ in their ability to bind heparan sulfate proteoglycan. RPE normally pr...

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

authors： Saint-Geniez M,Kurihara T,Sekiyama E,Maldonado AE,D'Amore PA

更新日期：2009-11-03 00:00:00

abstract：:Both 2-lysophosphatidylcholine and cis-unsaturated fatty acids were previously shown to intensify agonist-induced cellular responses by enhancing the diacylglycerol-dependent activation of protein kinase C. Consistent with these observations, extracellular, secretory group II phospholipase A2, when added directly to h...

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

authors： Asaoka Y,Yoshida K,Sasaki Y,Nishizuka Y,Murakami M,Kudo I,Inoue K

更新日期：1993-01-15 00:00:00

abstract：:We report potent inhibition of the Mg(II).ATP-dependent protein phosphatase, Fc.M, by the regulatory subunit dimer of type II cAMP-dependent protein kinase, RII2. The protein kinase catalytic subunit has no effect on phosphatase activity and is unable to substitute for kinase FA in the kinase FA- and Mg(II).ATP-mediat...

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

authors： Jurgensen SR,Chock PB,Taylor S,Vandenheede JR,Merlevede W

更新日期：1985-11-01 00:00:00

abstract：:Swimming Escherichia coli responds to changes in temperature by modifying its motor behavior. Previous studies using populations of cells have shown that E. coli accumulate in spatial thermal gradients, but these experiments did not cleanly separate thermal responses from chemotactic responses. Here we have isolated t...

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

authors： Paster E,Ryu WS

更新日期：2008-04-08 00:00:00

abstract：:For length and area, a central fact is that the value of the length of a curve or the area of a surface, as given by the Lebesgue theory, is at least as great as that given by the classical formula, whenever the latter has meaning. This is now found not to be valid in higher dimensions. We give an example of a continu...

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

authors： Goffman C

更新日期：1969-05-01 00:00:00