Abstract:
:After collision with their host cells, virus particles may remain mobile on cell surfaces until they become attached at firm binding sites. We propose that a virion will arrive within a typical median time at such a site, generating a membrane signal such as an increased membrane fluorescence in cells labeled with the voltage-sensitive dyes 8-anilino-1-naphthalene-sulfonate (Mg-salt) (ANS), N-phenylnaphthylamine (NPA), or 3,3'-dipentyl-2,2'-oxacarbocyanine (di-O-C5[3]). We found that the time span between virus adsorption and fluorescence response varies widely among phages and also depends on bacterial strain, metabolic state, and type of dye. di-O-C5[3]-labeled cells react within 1 sec to uncouplers such as carbonyl cyanide m-chlorophenylhydrazone (CCCP). Cells labeled with ANS and NPA react to CCCP in 4-6 sec. Bacteriophages T4, T5, chi, and BF23, added to ANS-labeled cells, change the fluorescence in 9-15 sec. T-even ghosts cause a response at identical times. Baseplate-defective phage mutant T412- and isolated adsorption organelles of smaller viruses fail to cause an effect. di-O-C5[3]-labeled cells respond to T4 at a multiplicity of infection greater than or equal to 40 within 1 sec. A longer time (8 sec) is required at lower multiplicities. The receptor-degrading phages epsilon 15, epsilon 34, c 341, and K29 need the longest time (1 min for ANS) to cause a fluorescence increase. We suggest that the delayed fluorescence response is concomitant with the surface "walk" of the virion, which is terminated at an injection site. T4 tail sheath contraction coincides with the onset of the membrane fluorescence response.
journal_name
Proc Natl Acad Sci U S Aauthors
Bayer ME,Bayer MHdoi
10.1073/pnas.78.9.5618subject
Has Abstractpub_date
1981-09-01 00:00:00pages
5618-22issue
9eissn
0027-8424issn
1091-6490journal_volume
78pub_type
杂志文章abstract::Mechanisms leading to down-regulation of activated microglia and astrocytes are poorly understood, in spite of the potentially detrimental role of activated glia in neurodegeneration. Prostaglandins, produced both by neurons and glia, may serve as mediators of glial and neuronal functions. We examined the influence of...
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.96.8.4668
更新日期:1999-04-13 00:00:00
abstract::Many paleoredox proxies indicate low-level and dynamic incipient oxygenation of Earth's surface environments during the Neoarchean (2.8-2.5 Ga) before the Great Oxidation Event (GOE) at ∼2.4 Ga. The mode, tempo, and scale of these redox changes are poorly understood, because data from various locations and ages sugges...
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.1720820115
更新日期:2018-07-24 00:00:00
abstract::Using both heterologous rabbit antisera and mouse monoclonal antibody to RNA.DNA hybrids, we have mapped the in situ hybridization locus of the 18/28S ribosomal RNA fraction to a single large band on polytene autosome 3 in Drosophila heteroneura and Drosophila silvestris. This portion of the chromosome is not physical...
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.78.6.3751
更新日期:1981-06-01 00:00:00
abstract::Linkage analysis with restriction fragment length polymorphisms for the gene for type II procollagen (COL2A1) was carried out in a family with the Stickler syndrome, or arthro-ophthalmopathy, an autosomal dominant disorder that affects the eyes, ears, joints, and skeleton. The analysis demonstrated linkage of the dise...
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.88.15.6624
更新日期:1991-08-01 00:00:00
abstract::Despite the success statistical physics has enjoyed at predicting the properties of materials for given parameters, the inverse problem, identifying which material parameters produce given, desired properties, is only beginning to be addressed. Recently, several methods have emerged across disciplines that draw upon o...
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.1509316112
更新日期:2016-01-05 00:00:00
abstract::Rhizobia colonize their legume hosts by different modes of entry while initiating symbiotic nitrogen fixation. Most legumes are invaded via growing root hairs by the root hair-curl mechanism, which involves epidermal cell responses. However, invasion of a number of tropical legumes happens through fissures at lateral ...
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.0401540101
更新日期:2004-04-20 00:00:00
abstract::Despite their importance for biological activity, slower molecular motions beyond the nanosecond range remain poorly understood. We have assembled an unprecedented set of experimental NMR data, comprising up to 27 residual dipolar couplings per amino acid, to define the nature and amplitude of backbone motion in prote...
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.0505129102
更新日期:2005-09-27 00:00:00
abstract::We describe a Xenopus mRNA, Xrel1, that is related to the avian protooncogene c-rel, the embryonic pattern gene dorsal of Drosophila, and the mammalian transcription factor NK-kappa B/KBF1. The sequence of Xrel1 is homologous to the other rel-related proteins in the large amino-terminal region that defines this class ...
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.88.7.2697
更新日期:1991-04-01 00:00:00
abstract::Schizosaccharomyces pombe cells were transformed with an S. pombe expression vector containing a full-length cDNA of the Chlorella hexose transporter. The transformed cells accumulated 3-O-methylglucose up to 10-fold, whereas wild-type S. pombe and control transformants could only equilibrate this sugar analogue. In a...
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.87.20.7949
更新日期:1990-10-01 00:00:00
abstract::Chaperones of the Hsp70 family bind to unfolded or partially folded polypeptides to facilitate many cellular processes. ATP hydrolysis and substrate binding, the two key molecular activities of this chaperone, are modulated by the cochaperone DnaJ. By using both genetic and biochemical approaches, we provide evidence ...
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.95.26.15223
更新日期:1998-12-22 00:00:00
abstract::New Zealand Black (NZB) mice develop after 16 weeks of age an autoimmune and lymphoproliferative disease which is a model for systemic lupus erythematosus and lymphoid malignancy in humans. At this age, the mice manifest a progressive decline in T lymphocyte (thymus-derived lymphocyte) functions and serum thymosin lev...
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.71.7.2637
更新日期:1974-07-01 00:00:00
abstract::Metabolic imaging of the relative amounts of reduced NADH and FAD and the microenvironment of these metabolic electron carriers can be used to noninvasively monitor changes in metabolism, which is one of the hallmarks of carcinogenesis. This study combines cellular redox ratio, NADH and FAD lifetime, and subcellular m...
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.0708425104
更新日期:2007-12-04 00:00:00
abstract::Volcanic eruptions caused major weather and climatic changes on timescales ranging from hours to centuries in the past. Volcanic particles are injected in the atmosphere both as primary particles rapidly deposited due to their large sizes on time scales of minutes to a few weeks in the troposphere, and secondary parti...
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.1104923108
更新日期:2011-07-26 00:00:00
abstract::Cleavage of the hemagglutinin (HA) in tissue culture systems has been correlated with virulence of avian influenza viruses. To examine the structural requirements for cleavage of the HA, the HA gene from a virulent H5 influenza virus was expressed in mammalian cells (CV-1), and the cleavage site of the HA was explored...
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.85.2.324
更新日期:1988-01-01 00:00:00
abstract::Is there a sense of chance shared by all individuals, regardless of their schooling or culture? To test whether the ability to make correct probabilistic evaluations depends on educational and cultural guidance, we investigated probabilistic cognition in preliterate and prenumerate Kaqchikel and K'iche', two indigenou...
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.1410583111
更新日期:2014-12-02 00:00:00
abstract::The mechanisms that regulate hematopoietic stem cell (HSC) fate decisions between proliferation and multilineage differentiation are unclear. Members of the Wnt family of ligands that activate the canonical Wnt signaling pathway, which utilizes beta-catenin to relay the signal, have been demonstrated to regulate HSC 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.0704747104
更新日期:2007-09-25 00:00:00
abstract::The combination of catalytic amounts of optically active dipyridylphosphine and CuF(2) along with hydride donor PhSiH(3) generated in situ a remarkably reactive catalyst system (substrate-to-ligand molar ratio up to 100,000) for the highly enantioselective hydrosilylation of a broad spectrum of aryl alkyl ketones (up ...
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.0409043102
更新日期:2005-03-08 00:00:00
abstract::We have used the polymerase chain reaction to amplify the entire coding region of canine factor IX from a hemophilia B animal. When the sequence was compared to that which codes for normal canine factor IX, a single missense mutation was identified. This mutation (G----A at nucleotide 1477) results in the substitution...
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.86.24.10095
更新日期:1989-12-01 00:00:00
abstract::Chromosomes are compacted hundreds of times to fit in the cell, packaged into dynamic folds whose structures are largely unknown. Here, we examine patterns in gene locations to infer large-scale features of bacterial chromosomes. Specifically, we analyzed >100 genomes and identified thousands of gene pairs that displa...
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.0610776104
更新日期:2007-06-19 00:00:00
abstract::Understanding and manipulation of the forces assembling DNA/RNA helices have broad implications for biology, medicine, and physics. One subject of significance is the attractive force between dsDNA mediated by polycations of valence ≥ 3. Despite extensive studies, the physical origin of the "like-charge attraction" re...
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.1003374107
更新日期:2010-12-14 00:00:00
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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.95.21.12707
更新日期:1998-10-13 00:00:00
abstract::IFN-alpha/beta plays an essential role in innate immunity against viral and bacterial infection. Among the proteins induced by IFN-alpha/beta are the ubiquitin-like ISG15 protein and its E1- (Ube1L) and E2- (UbcH8) conjugating enzymes, leading to the conjugation of ISG15 to cellular proteins. It is likely that ISG15 c...
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.0504754102
更新日期:2005-07-19 00:00:00
abstract::Long-term depression (LTD) is held relevant to memory and learning. Its induction is known to require postsynaptic calcium increases. However, the source of these calcium increases remains unclear. In visual cortex slices, LTD was induced by tetanization after blockade of N-methyl-D-aspartate (NMDA) and non-NMDA ionot...
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.90.8.3650
更新日期:1993-04-15 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
pub_type: 杂志文章
doi:10.1073/pnas.84.6.1694
更新日期:1987-03-01 00:00:00
abstract::The unfolded protein response (UPR) is an evolutionarily conserved mechanism by which all eukaryotic cells adapt to the accumulation of unfolded proteins in the endoplasmic reticulum (ER). Inositol-requiring kinase 1 (IRE1) and PKR-related ER kinase (PERK) are two type I transmembrane ER-localized protein kinase recep...
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.0606480103
更新日期:2006-09-26 00:00:00
abstract::Five instances of association between distinctive stromatolites and blue-green algal nannofossils are recorded from a 100-m sequence of carbonate rocks about 1.6 x 10(9) years old, along the south side of Paradise Creek, northwestern Queensland, Australia. No eukaryotes were identified in any of these systematically l...
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.69.9.2500
更新日期:1972-09-01 00:00:00
abstract::Fifty cats with feline leukemia virus (FeLV) infection and leukemia-lymphoma complex were treated by ex vivo immunoadsorption with Staphylococcus protein A-bound filters. Most cats responded to therapy. Twelve showed tumor regression, including disappearance of tumor cells, but died later of other complications. Three...
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.81.11.3516
更新日期:1984-06-01 00:00:00
abstract::A major challenge of cancer immunotherapy is the persistence and outgrowth of subpopulations that lose expression of the target antigen. IL-15 is a potent cytokine that can promote organ-specific autoimmunity when up-regulated on tissue cells. Here we report that T cells eradicated 2-wk-old solid tumors that expressed...
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.1301022110
更新日期:2013-05-14 00:00:00
abstract::Osmotic stress responses are critical not only to the survival of unicellular organisms but also to the normal function of the mammalian kidney. However, the extent to which cells outside the kidney rely on osmotic stress responses in vivo remains unknown. Nuclear factor of activated T cells 5 (NFAT5)/tonicity enhance...
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.0403139101
更新日期:2004-07-20 00:00:00
abstract::Active coping underlies a healthy stress response, but neural processes supporting such resilient coping are not well-known. Using a brief, sustained exposure paradigm contrasting highly stressful, threatening, and violent stimuli versus nonaversive neutral visual stimuli in a functional magnetic resonance imaging (fM...
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.1600965113
更新日期:2016-08-02 00:00:00