Abstract:
:Treatment of small resting B cells with soluble F(ab')2 fragments of anti-IgM, an analogue of T-independent type 2 antigens, induced activation characterized by proliferation and the expression of surface CD5. In contrast, B cells induced to proliferate in response to thymus-dependent inductive signals provided by either fixed activated T-helper 2 cells or soluble CD40 ligand-CD8 (CD40L) recombinant protein displayed elevated levels of CD23 (Fc epsilon II receptor) and no surface CD5. Treatment with anti-IgM and CD40L induced higher levels of proliferation and generated a single population of B cells coexpressing minimal amounts of CD5 and only a slight elevation of CD23. Anti-IgM- but not CD40L-mediated activation was highly sensitive to inhibition by cyclosporin A and FK520. Sp-cAMPS, an analogue of cAMP, augmented CD40L and suppressed surface IgM-mediated activation. Taken together these results are interpreted to mean that there is a single population of small resting B cells that can respond to either T-independent type 2 (surface IgM)- or T-dependent (CD40)-mediated activation. In response to different intracellular signals these cells are induced to enter alternative differentiation pathways.
journal_name
Proc Natl Acad Sci U S Aauthors
Wortis HH,Teutsch M,Higer M,Zheng J,Parker DCdoi
10.1073/pnas.92.8.3348subject
Has Abstractpub_date
1995-04-11 00:00:00pages
3348-52issue
8eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::We construct a class of global exact solutions of the Einstein equations that extend the Oppeheimer-Snyder model to the case of nonzero pressure, inside the black hole, by incorporating a shock wave at the leading edge of the expansion of the galaxies, arbitrarily far beyond the Hubble length in the Friedmann-Robertso...
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.1833875100
更新日期:2003-09-30 00:00:00
abstract::The cheA locus of Escherichia coli, which is required for chemotactic behavior, encodes two polypeptide products designated p[cheA]L and p[cheA]S. The mode of synthesis of these two proteins was investigated by transferring various missense and nonsense mutations to a lambda transducing phage and observing the mutant ...
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.77.9.5370
更新日期:1980-09-01 00:00:00
abstract::The E26 transformation-specific (Ets-1) transcription factor is autoinhibited by a conformationally disordered serine-rich region (SRR) that transiently interacts with its DNA-binding ETS domain. In response to calcium signaling, autoinhibition is reinforced by calmodulin-dependent kinase II phosphorylation of serines...
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.1401891111
更新日期:2014-07-29 00:00:00
abstract::Transgenic mice harboring the int-2/Fgf-3 protooncogene under transcriptional control of the mouse mammary tumor virus (MMTV) promoter/enhancer exhibit a dramatic, benign hyperplasia of the mammary gland. In one int-2 transgenic line (TG.NX), this growth disturbance is evoked by pregnancy and regresses after parturiti...
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.92.6.2268
更新日期:1995-03-14 00:00:00
abstract::A number of genes associated with sexual traits and reproduction evolve at the sequence level faster than the majority of genes coding for non-sex-related traits. Whole genome analyses allow this observation to be extended beyond the limited set of genes that have been studied thus far. We use cDNA microarrays to demo...
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.1630690100
更新日期:2003-08-19 00:00:00
abstract::Hybrid wheat plants are superior in yield and growth characteristics compared with their homozygous parents. The commercial production of wheat hybrids is difficult because of the inbreeding nature of wheat and the lack of a practical fertility control that enforces outcrossing. We describe a hybrid wheat system that ...
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.1402836111
更新日期:2014-06-24 00:00:00
abstract::This article emphasizes the role played by a remarkable pointwise inequality satisfied by fractionary derivatives in order to obtain maximum principles and Lp-decay of solutions of several interesting partial differential equations. In particular, there are applications to quasigeostrophic flows, in two space variable...
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.2036515100
更新日期:2003-12-23 00:00:00
abstract::Preincubation of quiescent BALB/C3T3 cells with uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) in conditioned medium resulted in a time- and concentration-dependent stimulation of uptake of 2-deoxyglucose, uridine, and alpha-aminoisobutyric acid over that seen in conditioned medium alone. The apparent Km values ...
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.75.8.3859
更新日期:1978-08-01 00:00:00
abstract::Aerosols impact climate, human health, and the chemistry of the atmosphere, and aerosol pH plays a major role in the physicochemical properties of the aerosol. However, there remains uncertainty as to whether aerosols are acidic, neutral, or basic. In this research, we show that the pH of freshly emitted (nascent) sea...
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.2018397118
更新日期:2021-01-12 00:00:00
abstract::Facial expressions of emotion in humans are believed to be produced by contracting one's facial muscles, generally called action units. However, the surface of the face is also innervated with a large network of blood vessels. Blood flow variations in these vessels yield visible color changes on the face. Here, we stu...
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.1716084115
更新日期:2018-04-03 00:00:00
abstract::The demonstration of enzymatic capabilities of certain RNAs, in addition to their well-known template properties, has led to the recognition that RNAs are the only biological macromolecules that can function both as genotype and phenotype, hence raising the possibility of Darwinian selection and precellular evolution ...
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.86.23.9370
更新日期:1989-12-01 00:00:00
abstract::We previously identified a stromal cell-derived inducing activity (SDIA), which induces differentiation of neural cells, including midbrain tyrosine hydroxylase-positive (TH(+)) dopaminergic neurons, from mouse embryonic stem cells. We report here that SDIA induces efficient neural differentiation also in primate embr...
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.032662199
更新日期:2002-02-05 00:00:00
abstract::Tropospheric O(3) and sulfate both contribute to air pollution and climate forcing. There is a growing realization that air quality and climate change issues are strongly connected. To date, the importance of the coupling between O(3) and sulfate has not been fully appreciated, and thus regulations treat each pollutan...
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.0508769103
更新日期:2006-03-21 00:00:00
abstract::Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic 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.1204237109
更新日期:2012-08-14 00:00:00
abstract::Neuronal signal integration as well as synaptic transmission and plasticity highly depend on the morphology of dendrites and their spines. Nogo-A is a membrane protein enriched in the adult central nervous system (CNS) myelin, where it restricts the capacity of axons to grow and regenerate after injury. Nogo-A is also...
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.1214255110
更新日期:2013-01-15 00:00:00
abstract::We have used DNA transfection to identify several regions of the adenovirus genome needed to induce replication of the defective parvovirus, adenovirus-associated virus (AAV). Previous studies have indicated that only early adenovirus functions are needed to aid the replication of AAV. In this report, we demonstrate t...
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.78.3.1925
更新日期:1981-03-01 00:00:00
abstract::Nitrogen limitation imposes a major transition in the lifestyle of nondiazotrophic cyanobacteria that is controlled by a complex interplay of regulatory factors involving the pervasive signal processor PII Immediately upon nitrogen limitation, newly fixed carbon is redirected toward glycogen synthesis. How the metabol...
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.2019988118
更新日期:2021-02-09 00:00:00
abstract::Proopiomelanocortin (POMC), a major pituitary product, is also present in the adult mouse testis. We have shown previously that POMC mRNAs are most abundant in a subpopulation of Leydig cells associated with tubules in specific stages of the cycle of the seminiferous epithelium. In the present study, we examined the 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.84.6.1600
更新日期:1987-03-01 00:00:00
abstract::A molecular recognition code has been hypothesized to exist in which ligands and their binding sites are encoded on complementary segments of genomic DNA. We have tested this hypothesis by generating a rabbit antibody to a synthetic decapeptide (complementary peptide) encoded by an RNA complementary to the mRNA for lu...
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.83.24.9714
更新日期:1986-12-01 00:00:00
abstract::The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of (40)Ar/(39)Ar "plateau" ages (i.e., regions selected on the basis 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.1611535113
更新日期:2016-09-27 00:00:00
abstract::In the retina, dopamine plays a central role in neural adaptation to light. Progress in the study of dopaminergic amacrine (DA) cells has been limited because they are very few (450 in each mouse retina, 0.005% of retinal neurons). Here, we applied transgenic technology, single-cell global mRNA amplification, and cDNA...
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.0400913101
更新日期:2004-04-06 00:00:00
abstract::Results are reported showing that pituitary extracts stimulate growth of 3T3 cells, an established line of mouse fibroblast. Cells were cultured in medium containing an organic buffer (HEPES; N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid), which increases the serum requirement for cell growth. The pituitary grow...
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.70.9.2702
更新日期:1973-09-01 00:00:00
abstract::Go is a specific class ("other") of signal-transducing heterotrimeric GTP-binding proteins (G proteins) that is expressed in high levels in mammalian brain. We have cloned two different rat cDNAs encoding the alpha subunit of Go (Go alpha-1 and Go alpha-2) and a human Go alpha chromosomal gene. The human Go alpha gene...
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.88.8.2974
更新日期:1991-04-15 00:00:00
abstract::An intense investigation of possible non-Fermi liquid states of matter has been inspired by two of the most intriguing phenomena discovered in the past quarter century, namely, high-temperature superconductivity and the fractional quantum Hall effect. Despite enormous conceptual strides, these two fields have develope...
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.0902901106
更新日期:2009-06-09 00:00:00
abstract::Several 400- to 800-kb murine chromosome domains switch from early to late replication during loss of pluripotency, accompanied by a stable form of gene silencing that is resistant to reprogramming. We found that, whereas enhanced nuclease accessibility correlated with early replication genome-wide, domains that switc...
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.1207185109
更新日期:2012-07-31 00:00:00
abstract::The exceptional sensitivity of Mycobacterium tuberculosis to isonicotinic acid hydrazide (INH) lacks satisfactory definition. M. tuberculosis is a natural mutant in oxyR, a central regulator of peroxide stress response. The ahpC gene, which encodes a critical subunit of alkyl hydroperoxide reductase, is one of the tar...
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.93.23.13212
更新日期:1996-11-12 00:00:00
abstract::Long QT syndrome (LQT) is an autosomal dominant disorder that can cause sudden death from cardiac arrhythmias. We recently discovered that mutations in HERG, a K+-channel gene, cause chromosome 7-linked LQT. Heterologous expression of HERG in Xenopus oocytes revealed that HERG current was similar to a well-characteriz...
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.93.5.2208
更新日期:1996-03-05 00:00:00
abstract::The Ca2+/calmodulin (CaM)-dependent protein phosphatase calcineurin is rapidly phosphorylated (0.8 mol of 32PO4 per mol of 60-kDa subunit of calcineurin) by brain Ca2+/CaM-dependent protein kinase II (CaM-kinase II). This reaction requires the autophosphorylated, Ca2+-independent form of CaM-kinase II since Ca2+/CaM b...
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.85.18.7001
更新日期:1988-09-01 00:00:00
abstract::Unlike the dominant role of one class II invariant chain peptide (CLIP) in blocking MHC class II, comparative lipidomics analysis shows that human cluster of differentiation (CD) proteins CD1a, CD1b, CD1c, and CD1d bind lipids corresponding to hundreds of diverse accurate mass retention time values. Although most ions...
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.1112969108
更新日期:2011-11-29 00:00:00
abstract::Cancer patients and tumor-bearing mice possess serum antibodies that recognize antigens expressed by cancer cells at the time of diagnosis. After diagnosis, cancers progress to more aggressive stages, most often by acquiring new genetic changes that can give rise to new proteins, some of which are antigenic. However, ...
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.0930140100
更新日期:2003-04-29 00:00:00