Abstract:
:Antigen.antibody complexes (Ag.Ab) prepared from (125)I-labeled bovine serum albumin and guinea pig anti-albumin were incubated at 37 degrees C for 30 min with normal human serum diluted optimally for binding (1:16) and then with autologous erythrocytes (RBC). After washing, RBC-bearing antigen.antibody.complement complexes (Ag.Ab.C) were resuspended in serum reagents or solutions of purified complement components, and the kinetics of dissociation were analyzed. Ag.Ab.C dissociated in serum heated at 56 degrees C for 30 min (SDelta30) but not in serum heated for 120 min (SDelta120). Dissociation in SDelta30 markedly decreased after adsorption with anti-C3b inactivator but not anti-beta1H or anti-C4 binding protein (C4bp), and dissociation in SDelta120 markedly increased after addition of C3b inactivator. Hemolytic assays revealed that SDelta30 retained inactivator activity whereas SDelta120 lacked significant activity. Ag.Ab.C dissociated in the presence of purified inactivator or C3b but not beta1H or C3. Dissociation was more rapid with inactivator than with C3b and occurred at 0 degrees C as well as at 37 degrees C. Treatment with inactivator inhibitor abolished dissociation in SDelta30; dissociation in inactivator deficient serum was markedly reduced. Addition of beta1H did not enhance inactivator-mediated dissociation at limiting dilutions of inactivator, and adsorption of Ag.Ab.C with anti-beta1H or preparation of Ag.Ab.C with serum adsorbed with anti-beta1H did not diminish dissociation. After dissociation with inactivator, Ag.Ab.C were unchanged in size but were no longer able to bind to fresh RBC and gave enhanced binding to Raji and Daudi lymphoblastoid cells. NaDodSO(4)/polyacrylamide gel electrophoresis of Ag.Ab.C prepared with (125)I-labeled C3 revealed that, after binding to RBC, dissociation with inactivator was accompanied by generation of a C3 fragment the size of C3c. Preincubation of Ag.Ab.C with excess inactivator did not prevent subsequent binding of Ag.Ab.C to RBC but, immediately after binding, Ag.Ab.C dissociated rapidly. These findings indicate that C3b inactivator can release immune complexes from immune adherence receptors on human RBC, that release occurs independently of beta1H, alters cell binding properties of immune complexes, and involves multiple cleavages of the C3b alpha' chain, and that receptors in human RBC membrane are required for this C3b inactivator-mediated breakdown.
journal_name
Proc Natl Acad Sci U S Aauthors
Medof ME,Prince GM,Mold Cdoi
10.1073/pnas.79.16.5047subject
Has Abstractpub_date
1982-08-01 00:00:00pages
5047-51issue
16eissn
0027-8424issn
1091-6490journal_volume
79pub_type
杂志文章abstract::Little is known about how members of the indigenous microflora interact with their mammalian hosts to establish mutually beneficial relationships. We have used a gnotobiotic mouse model to show that Bacteroides thetaiotaomicron, a component of the intestinal microflora of mice and humans, uses a repressor, FucR, as 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.96.17.9833
更新日期:1999-08-17 00:00:00
abstract::We describe a Kappa-on-Heavy (KoH) mouse that produces a class of highly diverse, fully human, antibody-like agents. This mouse was made by replacing the germline variable sequences of both the Ig heavy-chain (IgH) and Ig kappa (IgK) loci with the human IgK germline variable sequences, producing antibody-like molecule...
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.1901734117
更新日期:2020-01-07 00:00:00
abstract::Intracolonic administration of trinitrobenzene sulfonic acid in mice causes inflammation in the colon that is accompanied by increased expression of proinflammatory cytokines and of the substance P (SP), neurokinin 1 receptor (NK-1R) in the proximal mesenteric fat depot. We also investigated whether human mesenteric p...
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.0600821103
更新日期:2006-03-28 00:00:00
abstract::Ubiquitylation of proteins can be a signal for a variety of cellular processes beyond the classical role in proteolysis. The different signaling functions of ubiquitylation are thought to rely on ubiquitin-binding domains (UBDs). Several distinct UBD families are known, but their functions are not understood in detail...
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.1010648107
更新日期:2010-11-16 00:00:00
abstract::A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific id...
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.1511006112
更新日期:2015-07-14 00:00:00
abstract::Protein-protein and protein-ligand interactions are ubiquitous in a biological cell. Here, we report a comprehensive study of the distribution of protein-ligand interaction sites, namely ligand-binding pockets, around protein-protein interfaces where protein-protein interactions occur. We inspected a representative se...
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.1117768109
更新日期:2012-03-06 00:00:00
abstract::Ventriculo-cisternal perfusion of horseradish peroxidase (HRP) in the mouse brain has demonstrated that a brain-blood barrier exists at the microvascular endothelium in brain parenchyma but not in the median eminence of the hypothalamus. The brain-blood barrier is similar to the blood-brain barrier in that: tight junc...
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.80.23.7352
更新日期:1983-12-01 00:00:00
abstract::Solid-state cross-polarization/magic-angle sample-spinning (13)C NMR spectra have been recorded on chlorophyll a-water aggregates, methyl pyrochlorophyllide a, and methyl pyropheophorbide a (derivatives that lack a phytyl chain). Spectra have also been collected under a decoupling regime in which resonances of certain...
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.81.2.641
更新日期:1984-01-01 00:00:00
abstract::Molybdate- and ATP-dependent in vitro synthesis of the iron-molybdenum cofactor (FeMo-co) of nitrogenase requires the protein products of at least the nifB, nifN, and nifE genes. Extracts of FeMo-co-negative mutants of Klebsiella pneumoniae and Azotobacter vinelandii with lesions in different genes can be complemented...
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.83.6.1636
更新日期:1986-03-01 00:00:00
abstract::Human X chromosome DNA was partially purified from a mouse-human hybrid cell line containing a single human chromosome, the X. Enrichment of such DNA was accomplished by two sequential reassociations of radiolabeled hybrid cell DNA with large excesses of mouse DNA. Unreassociated hybrid cell DNA was used as a probe fo...
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.76.12.6525
更新日期:1979-12-01 00:00:00
abstract::A recently discovered family of natural anion channelrhodopsins (ACRs) have the highest conductance among channelrhodopsins and exhibit exclusive anion selectivity, which make them efficient inhibitory tools for optogenetics. We report analysis of flash-induced absorption changes in purified wild-type and mutant ACRs,...
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.1525269113
更新日期:2016-04-05 00:00:00
abstract::Aqueous gel sieving chromatography on Sephadex G-10 of the Group IA cations (Li+, Na+, K+, Rb+, Cs+) plus NH4+ as the Cl- salts, in combination with previous results for the halide anions (F-, Cl-, Br-, I-) as the Na+ salts [Washabaugh, M.W. & Collins, K.D. (1986) J. Biol. Chem. 261, 12477-12485], leads to the followi...
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.92.12.5553
更新日期:1995-06-06 00:00:00
abstract::Experimental exclusion of the Andean flamingo (Phoenicoparrus andinus) from shallow water areas of a salt lake in the Bolivian Andes caused large increases in the biomass of microorganisms inhabiting the surface sediments, especially a large diatom (Surirella wetzeli), amebas, ciliates, and nematodes. This is a conser...
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.80.15.4766
更新日期:1983-08-01 00:00:00
abstract::From 25 to 29 April 2020, the state of Indiana undertook testing of 3,658 randomly chosen state residents for the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, the agent causing COVID-19 disease. This was the first statewide randomized study of COVID-19 testing in the United States. Both PC...
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.2013906118
更新日期:2021-02-02 00:00:00
abstract::The Notch-signaling pathway controls cellular differentiation, including proliferation and cell death in all higher metazoans (including flies and men). Signal transduction through activated Notch involves the CSL group of transcriptional regulators. Notch signals need to be tightly regulated, and in Drosophila they 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.242596699
更新日期:2002-11-26 00:00:00
abstract::The AF-6 protein is a multidomain protein that contains two potential Ras-binding domains within its N terminus. Because of this feature, AF-6 has been isolated in both two-hybrid and biochemical approaches and is postulated to be a potential Ras-effector protein. Herein, we show that it is specifically the first Ras-...
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.97.16.9064
更新日期:2000-08-01 00:00:00
abstract::In vitro DNA synthesis was studied in HeLa cell nuclei, with emphasis on the question of whether newly replicated DNA is associated with nucleosomes. The newly replicated DNA was twice as sensitive to digestion by micrococcal nuclease as mature chromatin DNA, reaching a limit digest at 20-25% acid-insoluble product. E...
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.75.6.2717
更新日期:1978-06-01 00:00:00
abstract::The inhibitory protein that binds calmodulin and thus prevents activation of several Ca2+-dependent enzymes by calmodulin is shown to also bind four Ca2+ per mol of protein with high affinity (Kd less than or equal to 10(-6) M). On the basis of its Ca2+- binding properties and its localization to nervous tissue, the i...
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.76.12.6270
更新日期:1979-12-01 00:00:00
abstract::A genetic complementation system was developed in which tobacco etch virus (TEV) polymerase (NIb)-expressing transgenic plants or protoplasts were inoculated with NIb-defective TEV mutants. A beta-glucuronidase (GUS) reporter gene integrated into the genomes of parental and four mutant viruses was used to assay RNA am...
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.92.2.457
更新日期:1995-01-17 00:00:00
abstract::Recent findings intriguingly place DNA double-strand break repair proteins at chromosome ends in yeast, where they help maintain normal telomere length and structure. In the present study, an essential telomere function, the ability to cap and thereby protect chromosomes from end-to-end fusions, was assessed in repair...
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.96.26.14899
更新日期:1999-12-21 00:00:00
abstract::Chronic inflammation is a major risk factor for colorectal cancer. The p38/MAPKAP Kinase 2 (MK2) kinase axis controls the synthesis of proinflammatory cytokines that mediate both chronic inflammation and tumor progression. Blockade of this pathway has been previously reported to suppress inflammation and to prevent co...
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.1722020115
更新日期:2018-05-01 00:00:00
abstract::Dense granules of platelets contain a high content of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A). We have previously demonstrated an antithrombotic effect of this compound in a live rabbit model. In the present study we find that certain synthetic Ap4A analogues are superior to Ap4A in inhibiting ADP-induced aggr...
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.89.6.2370
更新日期:1992-03-15 00:00:00
abstract::Growing human and ecological costs due to increasing wildfire are an urgent concern in policy and management, particularly given projections of worsening fire conditions under climate change. Thus, understanding the relationship between climatic variation and fire activity is a critically important scientific question...
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.1713885114
更新日期:2017-12-26 00:00:00
abstract::The tissue-specific expression of the chicken liver cell adhesion molecule (L-CAM) was studied by generating transgenic mice. The rat insulin II promoter was fused to a chicken L-CAM cDNA or to chicken genomic L-CAM sequences. Mice carrying the cDNA showed no expression of L-CAM. Mice carrying L-CAM genomic sequences ...
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.87.22.9042
更新日期:1990-11-01 00:00:00
abstract::TIM-4, a member of the TIM family expressed on antigen-presenting cells, binds to phosphatidylserine exposed on the surface of apoptotic bodies. However, the significance of this interaction in vivo remains unknown because other receptors have been implicated in the clearance of apoptotic bodies and could compensate 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.0910359107
更新日期:2010-05-11 00:00:00
abstract::The remarkable strength of glasses is examined using the random first order transition theory of the glass transition. The theory predicts that strength depends on elastic modulus but also on the configurational energy frozen in when the glass is prepared. The stress catalysis of cooperative rearrangements of the type...
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.1214130109
更新日期:2012-10-02 00:00:00
abstract::The mechanism of preferential transmission (i.e., maternal inheritance) of cytoplasmic genes was investigated with chloroplast DNA of Chlamydomonas as a model system. The behavior of nuclear and chloroplast DNAs were compared in the sexual cycle; DNAs from male and female parents were distinguished by labeling with (1...
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.69.9.2410
更新日期:1972-09-01 00:00:00
abstract::Synapsins are abundant synaptic-vesicle phosphoproteins that are known to regulate neurotransmitter release but whose precise function has been difficult to pinpoint. Here, we use knockout mice to analyze the role of synapsins 1 and 2 in the calyx of Held synapse, allowing precise measurements of neurotransmitter rele...
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.0511300103
更新日期:2006-02-21 00:00:00
abstract::Over the past decade or more, contradictory evidence of Martian climate, indicating that surface temperatures seldom if ever approach the melting point of water at midlatitudes, and geomorphic features, consistent with liquid flows at these same latitudes, have proven difficult to reconcile. In this article, we demons...
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.0308251101
更新日期:2004-06-08 00:00:00
abstract::This paper describes a variety of statistical methods for obtaining precise quantitative estimates of the similarities and differences in the structures of semantic domains in different languages. The methods include comparing mean correlations within and between groups, principal components analysis of interspeaker 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.97.1.518
更新日期:2000-01-04 00:00:00