Abstract:
:In this report, we explore the nature of the inductive stimuli leading to expression of the divergently regulated lymphokines interleukin 2 (IL-2) and interleukin 4 (IL-4). Elevation of cAMP levels blocks IL-2 induction while sparing IL-4 induction. These effects are gene-specific, not cell-specific, and can be observed in the same cells. Transient transfection experiments using murine IL-2 regulatory sequences to drive expression of a reporter gene show at least part of the inhibition to act at the transcriptional level. The possible biological significance of these results is indicated by the observation that representative type 2 helper T-cell lines maintain significantly higher levels of cAMP per cell than a type 1 helper T-cell line. Fresh splenic CD4+ T cells, which preferentially make IL-2, have particularly low levels of cAMP per cell and a low capacity to elevate cAMP in response to forskolin. However, their response to forskolin increases significantly after several days of stimulation. These results suggest a potential link between differential cAMP regulation and the divergence of memory T cells into effector subsets.
journal_name
Proc Natl Acad Sci U S Aauthors
Novak TJ,Rothenberg EVdoi
10.1073/pnas.87.23.9353subject
Has Abstractpub_date
1990-12-01 00:00:00pages
9353-7issue
23eissn
0027-8424issn
1091-6490journal_volume
87pub_type
杂志文章abstract::Epilepsy is the most common neurological disorder of young humans. Each year 150,000 children in the United States experience their first seizure. Antiepileptic drugs (AEDs), used to treat seizures in children, infants, and pregnant women, cause cognitive impairment, microcephaly, and birth defects. The cause of unwan...
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.222550499
更新日期:2002-11-12 00:00:00
abstract::Circumnutation and winding in plants are universal growth movements that allow plants to survive despite their sessile nature. However, the detailed molecular mechanisms controlling these phenomena remain unclear. We previously found that a gravitropic mutant of Japanese morning glory (Pharbitis nil or Ipomoea nil), S...
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.0504617102
更新日期:2005-12-20 00:00:00
abstract::Crystals of myosin subfragment 1 from avian skeletal muscle have been grown reproducibly. They diffract x-rays to at least 4.5-A resolution. The subfragment 1 crystallizes in space group P2(1)2(1)2(1) where a = 107 A, b = 117 A, and c = 278 A. The cell dimensions and intensity distribution on x-ray diffraction photogr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:
更新日期:1984-07-01 00:00:00
abstract::Trial electron density functions have some conceptual and computational advantages over wave functions. The properties of some simple density functions for H(+) (2) and H(2) are examined. It appears that for a diatomic molecule a good density function would be given by rho = N(A(2) + B(2)), in which A and B are short ...
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.77.4.1725
更新日期:1980-04-01 00:00:00
abstract::We introduce a coarse-grained model for atomic glass formers. Its elements are physically motivated local microscopic dynamical rules parameterized by observables. Results of the model are established and used to interpret the measured behaviors of supercooled fluids approaching glass transitions. The model predicts 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.1233719100
更新日期:2003-08-19 00:00:00
abstract::The DNA adducts formed during incubation of the hepatocarcinogen N-hydroxy-2-acetylaminofluorene with Salmonella typhimurium tester strain TA1538 were investigated to determine if the covalently bound products were identical to those adducts found in rat liver DNA and to establish the biological significance of the ad...
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.79.17.5175
更新日期:1982-09-01 00:00:00
abstract::The molecular circadian clocks in the mammalian retina are locally synchronized by environmental light cycles independent of the suprachiasmatic nuclei (SCN) in the brain. Unexpectedly, this entrainment does not require rods, cones, or melanopsin (OPN4), possibly suggesting the involvement of another retinal photopigm...
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.1516259112
更新日期:2015-10-20 00:00:00
abstract::Erythropoietin, the hormone that is the primary regulator of erythrocyte production, has been purified from anemic-sheep plasma, with a purification factor of more than 1 million. Gel electrophoresis shows that the major contaminant is desialated erythropoietin. ...
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.68.4.697
更新日期:1971-04-01 00:00:00
abstract::Eosinophils have been associated with fibrosis. To investigate their direct role in fibrosis, human peripheral blood eosinophil sonicate was added to human lung or dermal fibroblasts, and proliferation ([(3)H]thymidine) and collagen synthesis ([(3)H]proline) were evaluated. Proliferation was enhanced significantly in ...
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.96.17.9660
更新日期:1999-08-17 00:00:00
abstract::Gold nanoparticles quench the fluorescence of cationic polyfluorene with Stern-Volmer constants (KSV) approaching 1011 M-1, several orders of magnitude larger than any previously reported conjugated polymer-quencher pair and 9-10 orders of magnitude larger than small molecule dye-quencher pairs. The dependence of KSV ...
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.1132025100
更新日期:2003-05-27 00:00:00
abstract::The yeast auxiliary transcription factor GAL11, a candidate for the coactivator, was partially purified from yeast cells, and its function was characterized in a cell-free transcription system. The partially purified GAL11 protein stimulated basal transcription from the CYC1 core promoter by a factor of 4-5 at the ste...
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.90.18.8382
更新日期:1993-09-15 00:00:00
abstract::Chromatin remodeling complexes have been implicated in the disruption or reformation of nucleosomal arrays resulting in modulation of transcription, DNA replication, and DNA repair. Here we report the isolation of WCRF, a new chromatin-remodeling complex from HeLa cells. WCRF is composed of two subunits, WCRF135, the ...
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.97.3.1038
更新日期:2000-02-01 00:00:00
abstract::A panel of rat monoclonal antibodies was used to classify mouse mast cells from four different sources on the basis of their surface determinants. Three populations of mast cells were derived by culturing normal bone marrow, spleen, and peripheral blood cells, whereas the fourth population was isolated directly from 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.80.19.5916
更新日期:1983-10-01 00:00:00
abstract::Protein stability is usually studied in simple buffered solutions, but most proteins function inside cells, where the heterogeneous and crowded environment presents a complex, nonideal system. Proteins are expected to behave differently under cellular crowding owing to two types of contacts: hard-core repulsions and w...
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.1312678110
更新日期:2013-11-26 00:00:00
abstract::Methane can be converted to triose dihydroxyacetone (DHA) by chemical processes with formaldehyde as an intermediate. Carbon dioxide, a by-product of various industries including ethanol/butanol biorefineries, can also be converted to formaldehyde and then to DHA. DHA, upon entry into a cell and phosphorylation to DHA...
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.1801002115
更新日期:2018-04-24 00:00:00
abstract::Magnetotactic bacteria synthesize highly uniform intracellular magnetite nanoparticles through the action of several key biomineralization proteins. These proteins are present in a unique lipid-bound organelle (the magnetosome) that functions as a nanosized reactor in which the particle is formed. A master regulator 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.1409256111
更新日期:2014-11-11 00:00:00
abstract::The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between anno Domini (A.D.) 1250 and 1810, coincident with sola...
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.0603118103
更新日期:2006-06-13 00:00:00
abstract::Habitat loss and disease are main drivers of global amphibian declines, yet the interaction between them remains largely unexplored. Here we show that paradoxically, habitat loss is negatively associated with occurrence, prevalence, and infection intensity of the chytrid fungus Batrachochytrium dendrobatidis (Bd) 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.1014497108
更新日期:2011-06-14 00:00:00
abstract::We describe a strategy to "revive" putatively pathogenic T cells from frozen specimens of human inflammatory target organs. To distinguish pathogenic from irrelevant bystander T cells, we focused on cells that were (i) clonally expanded and (ii) in direct morphological contact with a target cell. Using CDR3 spectratyp...
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.0604247103
更新日期:2006-08-08 00:00:00
abstract::Endogenous retroviruses (ERVs) are the remnants of ancient retroviral infections of germ cells and have been maintained in whole or part as heritable genomic elements. The last known endogenization events occurred several million years ago, and therefore stepwise analysis of retroviral endogenization has not been poss...
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.0704313104
更新日期:2007-10-30 00:00:00
abstract::Theory predicts that double-core-hole (DCH) spectroscopy can provide a new powerful means of differentiating between similar chemical systems with a sensitivity not hitherto possible. Although DCH ionization on a single site in molecules was recently measured with double- and single-photon absorption, double-core hole...
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.1111380108
更新日期:2011-10-11 00:00:00
abstract::Current theoretical models of the commons assert that common-pool resources can only be managed sustainably with clearly defined boundaries around both communities and the resources that they use. In these theoretical models, open access inevitably leads to a tragedy of the commons. However, in many open-access system...
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.1812028115
更新日期:2018-12-18 00:00:00
abstract::Recently, single molecule-based superresolution fluorescence microscopy has surpassed the diffraction limit to improve resolution to the order of 20 nm or better. These methods typically use image fitting that assumes an isotropic emission pattern from the single emitters as well as control of the emitter concentratio...
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.1216687109
更新日期:2012-11-20 00:00:00
abstract::Transgenic (Tg) mouse lines that express chimeric mouse-human prion protein (PrP), designated MHu2M, are susceptible to prions from patients with sporadic Creutzfeldt-Jakob disease (sCJD). With the aim of decreasing the incubation time to fewer than 200 days, we constructed transgenes in which one or more of the nine ...
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.2627989100
更新日期:2003-04-15 00:00:00
abstract::The posterodorsal part of the medial nucleus of the amygdala (MeAp) receives its major sensory input from the accessory olfactory bulb and projects massively to the medial preoptic nucleus and other sexually dimorphic hypothalamic nuclei thought to play key roles in mediating steroid-sensitive reproductive functions. ...
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.86.12.4766
更新日期:1989-06-01 00:00:00
abstract::Adult stem cells represent unique populations of undifferentiated cells with self-renewal capacity. In many tissues, stem cells divide less often than their progeny. It has been widely speculated, but largely untested, that their undifferentiated and quiescent state may make stem cells more efficient as donors for clo...
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.0611358104
更新日期:2007-02-20 00:00:00
abstract::We used a sensitive and specific cDNA polymerase chain reaction assay to detect hepatitis C virus (HCV) RNA in serum samples from 128 unselected southern African Blacks with hepatocellular carcinoma (HCC) and found HCV RNA in 26 (20.3%) of these patients. Antibodies to HCV (anti-HCV) were detected in 59 patients (46.1...
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.90.5.1848
更新日期:1993-03-01 00:00:00
abstract::Indoor residual spraying (IRS) is used to control visceral leishmaniasis (VL) in India, but it is poorly quality assured. Quality assurance was performed in eight VL endemic districts in Bihar State, India, in 2014. Residual dichlorodiphenyltrichloroethane (DDT) was sampled from walls using Bostik tape discs, and DDT ...
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.1507782112
更新日期:2015-07-14 00:00:00
abstract::We present the complete nucleotide and deduced amino acid sequences of a mouse epidermal keratin subunit of 60,000 Da. The keratin possesses a central alpha-helical domain of four tracts (termed 1A, 1B, 2A, and 2B) that can form coiled-coils, interspersed by short linker sequences, and has non-alpha-helical terminal d...
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.81.18.5709
更新日期:1984-09-01 00:00:00
abstract::Previous reconstructions of marine fishing fleets have aggregated data without regard to the artisanal and industrial sectors. Engine power has often been estimated from subsets of the developed world, leading to inflated results. We disaggregated data into three sectors, artisanal (unpowered/powered) and industrial, ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.1820344116
更新日期:2019-06-18 00:00:00