Abstract:
:Osedax is a recently discovered group of siboglinid annelids that consume bones on the seafloor and whose evolutionary origins have been linked with Cretaceous marine reptiles or to the post-Cretaceous rise of whales. Here we present whale bones from early Oligocene bathyal sediments exposed in Washington State, which show traces similar to those made by Osedax today. The geologic age of these trace fossils ( approximately 30 million years) coincides with the first major radiation of whales, consistent with the hypothesis of an evolutionary link between Osedax and its main food source, although older fossils should certainly be studied. Osedax has been destroying bones for most of the evolutionary history of whales and the possible significance of this "Osedax effect" in relation to the quality and quantity of their fossils is only now recognized.
journal_name
Proc Natl Acad Sci U S Aauthors
Kiel S,Goedert JL,Kahl WA,Rouse GWdoi
10.1073/pnas.1002014107subject
Has Abstractpub_date
2010-05-11 00:00:00pages
8656-9issue
19eissn
0027-8424issn
1091-6490pii
1002014107journal_volume
107pub_type
历史文章,杂志文章abstract::Over 30 viral-specified polypeptides are translated in vitro from RNA of cells productively infected with Epstein-Barr virus (EBV). The polypeptides map to sites in EBV DNA by hybrid selection. Almost all of the polypeptides are reactive with EBV immune human serum. Several of the polypeptides are part of the early an...
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.79.18.5698
更新日期:1982-09-01 00:00:00
abstract::Relatively little is known about neurobiological changes attributable to early-life stressors (e.g., orphanage rearing), even though they have been associated with a heightened risk for later psychopathology. Human neuroimaging and animal studies provide complementary insights into the neural basis of problem behavior...
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.1310163110
更新日期:2013-11-05 00:00:00
abstract::To investigate how cell population density influences the intracellular concentration of cyclic AMP we have measured adenylate cyclase and cyclic AMP phosphodiesterase activities and cyclic AMP levels at various stages of cell density in normal rat-kidney (NRK) cells, which exhibit contact-inhibition of growth, and 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.70.12.3802
更新日期:1973-12-01 00:00:00
abstract::Exposure of murine hepatoma (Hepa 1c1c7) cells to a variety of chemical agents known to protect animals against the neoplastic, mutagenic, and other toxic effects of chemical carcinogens results in dose- and time-dependent inductions of NAD(P)H:quinone reductase (EC 1.6.99.2). This enzyme protects against quinone toxi...
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.83.3.787
更新日期:1986-02-01 00:00:00
abstract::Because of the rise in atmospheric oxygen 2.3 billion years ago (Gya) and the subsequent changes in oceanic redox state over the last 2.3-1 Gya, trace metal bioavailability in marine environments has changed dramatically. Although theorized to have influenced the biological usage of metals leaving discernable genomic ...
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.0605798103
更新日期:2006-11-21 00:00:00
abstract::In animals, successful production of the visual chromophore (11-cis-retinal or derivatives thereof such as 11-cis-3-hydroxy-retinal) is essential for photoreceptor cell function and survival. These carotenoid-derived compounds must combine with a protein moiety (the opsin) to establish functional visual pigments. Evid...
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.0807805105
更新日期:2008-12-02 00:00:00
abstract::The rise of peptides with secondary structures and functions would have been a key step in the chemical evolution which led to life. As with modern biology, amino acid sequence would have been a primary determinant of peptide structure and activity in an origins-of-life scenario. It is a commonly held hypothesis 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.1711631114
更新日期:2017-09-12 00:00:00
abstract::We simulated the behavior of suspended carbon nanotube resonators over a broad range of temperatures to explore the physics of semiflexible polymers in underdamped environments. We find that thermal fluctuations induce strong coupling between resonance modes. This effect leads to spectral fluctuations that readily acc...
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.1216407109
更新日期:2012-11-20 00:00:00
abstract::25-Hydroxycholesterol is produced in mammalian tissues. The function of this oxysterol is unknown. Here we describe a central role for 25-hydroxycholesterol in regulating the immune system. In initial experiments, we found that stimulation of macrophage Toll-like receptors (TLR) induced expression of cholesterol 25-hy...
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.0909142106
更新日期:2009-09-29 00:00:00
abstract::Knowledge of the mechanisms by which a cell detects exogenous DNA is important for controlling pathogen infection, because most pathogens entail the presence of exogenous DNA in the cytosol, as well as for understanding the cell's response to artificially transfected DNA. The cellular response to pathogen invasion has...
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.1501235112
更新日期:2015-06-02 00:00:00
abstract::Alpha-Klotho (alpha-Kl) and its homolog, beta-Klotho (beta-Kl) are key regulators of mineral homeostasis and bile acid/cholesterol metabolism, respectively. FGF15/ humanFGF19, FGF21, and FGF23, members of the FGF19 subfamily, are believed to act as circulating metabolic regulators. Analyses of functional interactions ...
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.0913986107
更新日期:2010-01-26 00:00:00
abstract::The TFIID transcription initiation complex is composed of TBP and multiple TAFs. Studies in unicellular systems indicate that TAF250 is required for progression through G(1)/S of the cell cycle and repression of apoptosis. Here we extend these in vivo studies by determining the developmental requirements for TAF250 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.97.3.1154
更新日期:2000-02-01 00:00:00
abstract::The problem of the propagation of conformational changes over long distances or through a closely packed protein is shown to fit a model of a ligand-induced conformational change between two protein states selected by evolution. Moreover, the kinetics of the pathway between these states is also selected so that the en...
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.161239298
更新日期:2001-08-14 00:00:00
abstract::In the primary visual cortex (V1) of many mammalian species, neurons are spatially organized according to their preferred orientation into a highly ordered map. However, whether and how the various presynaptic inputs to V1 neurons are organized relative to the neuronal orientation map remain unclear. To address this 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.1719711115
更新日期:2018-05-29 00:00:00
abstract::An ability to safely harness the powerful regenerative potential of adult stem cells for clinical applications is critically dependent on a comprehensive understanding of the underlying mechanisms regulating their activity. Epithelial organoid cultures accurately recapitulate many features of in vivo stem cell-driven ...
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.2016806118
更新日期:2021-01-26 00:00:00
abstract::A Poincaré resolution is given for the supersymmetric ring of brackets over a signed alphabet. As a consequence, a resolution is found for the ring of coordinates of the Grassmanian variety in projective space over any infinite field. ...
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.88.18.8087
更新日期:1991-09-15 00:00:00
abstract::Oocyte endowment dwindles away during prepubertal and adult life until menopause occurs, and apoptosis has been identified as a central mechanism responsible for oocyte elimination. A few recent reports suggest that uncontrolled inflammation may adversely affect ovarian reserve. We tested the possible role of the proi...
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.1323955111
更新日期:2014-08-26 00:00:00
abstract::Over the past 50 y, behavioral experiments have produced a large body of evidence for the existence of a magnetic sense in a wide range of animals. However, the underlying sensory physiology remains poorly understood due to the elusiveness of the magnetosensory structures. Here we present an effective method for isola...
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.1205653109
更新日期:2012-07-24 00:00:00
abstract::Activated macrophages are described as classically activated or M1 type and alternatively activated or M2 type, depending on their response to proinflammatory stimuli and the expression of genetic markers including iNOS, arginase1, Ym1, and Fizz1. Here we report that Akt kinases differentially contribute to macrophage...
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.1119038109
更新日期:2012-06-12 00:00:00
abstract::The effects of phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinase C, on Na+ influx were investigated in cultured human foreskin fibroblasts (HSWP cells). We report here that in serum-deprived HSWP cells the addition of PMA alone has no significant effect on Na+ influx. However, the addition 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.82.23.8053
更新日期:1985-12-01 00:00:00
abstract::Cell variants resistant to the cytotoxic effect of mycophenolic acid, an inhibitor of IMP dehydrogenase (IMP:NAD+ oxidoreductase, EC 1.2.1.14), were selected by a one-step procedure from Chinese hamster V79 cells. The frequency of these variants was increased in a dose-dependent manner after treatment with the mutagen...
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.78.5.3151
更新日期:1981-05-01 00:00:00
abstract::The structure of the antigen-binding fragment (Fab) of an anti-phenylarsonate monoclonal antibody (36-71) bearing a major crossreacting idiotype of A/J mice has been solved and refined to an R factor of 19.3% at a resolution of 2.9 A. An initial electron density map was obtained with phase information from a total 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.87.1.338
更新日期:1990-01-01 00:00:00
abstract::DNA extracted from Dane particles has been characterized by gel electrophoresis and restriction enzyme cleavage with endonuclease R-HaeIII (from Hemophilus aegyptius). Dane particle DNA is proposed to be a double-stranded circular DNA approximately 3600 nucleotides in length containing a single-stranded gap of 600-210...
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.72.11.4597
更新日期:1975-11-01 00:00:00
abstract::Conjugation of drugs with antibodies to surface endothelial antigens is a potential strategy for drug delivery to endothelium. We studied antibodies to platelet-endothelial adhesion molecule 1 (PECAM-1, a stably expressed endothelial antigen) as carriers for vascular immunotargeting. Although 125I-labeled anti-PECAM 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.96.5.2379
更新日期:1999-03-02 00:00:00
abstract::Although neutrophils are known to be fundamental in controlling innate immune responses, their role in regulating adaptive immunity is just starting to be appreciated. We report that human neutrophils exposed to pregnancy hormones progesterone and estriol promote the establishment of maternal tolerance through the ind...
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.1611944114
更新日期:2016-12-27 00:00:00
abstract::High-resolution analyses of a late Holocene core from Kettle Lake in North Dakota reveal coeval fluctuations in loss-on-ignition carbonate content, percentage of grass pollen, and charcoal flux. These oscillations are indicative of climate-fuel-fire cycles that have prevailed on the Northern Great Plains (NGP) for mos...
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.0503621102
更新日期:2005-06-21 00:00:00
abstract::Cerebellar long-term depression (LTD) is a persistent attenuation of synaptic transmission at the parallel fiber-Purkinje cell synapse mediated by the removal of GluR2 subunit-containing alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The removal of AMPA receptors requires protein kinase C 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.0408278102
更新日期:2004-12-28 00:00:00
abstract::Selective lodgement or homing of transplanted hemopoietic stem cells in the recipient's bone marrow (BM) is a critical step in the establishment of long-term hemopoiesis after BM transplantation. However, despite its biologic and clinical significance, little is understood about the process of homing. In the present 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.92.21.9647
更新日期:1995-10-10 00:00:00
abstract::The heterodisaccharide lactose (1,4-O-beta-D-galactopyranosyl-D-glucose) induces cellulase formation in the ascomycete Hypocrea jecorina (= Trichoderma reesei). Lactose assimilation is slow, and the assimilation of its beta-D-galactose moiety depends mainly on the operation of a recently described reductive pathway an...
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.0802789105
更新日期:2008-05-20 00:00:00
abstract::Facilitation of social attraction and bonding by the evolutionarily conserved neuropeptide oxytocin is well-established in female mammals. However, accumulating behavioral evidence suggests that oxytocin may have evolved sex-specific functional roles in the domain of human social cognition. A critical question is how ...
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.1602620113
更新日期:2016-07-05 00:00:00