Abstract:
:The central limit theorem is applied to group foraging to show an automatic and universal benefit to group living. This may explain the paradoxical inverse correlation between group size and per capita brood production in primitively eusocial insects and why only one of the five major lineages of social insects contains species that revert to solitary habit.
journal_name
Proc Natl Acad Sci U S Aauthors
Wenzel JW,Pickering Jdoi
10.1073/pnas.88.1.36keywords:
subject
Has Abstractpub_date
1991-01-01 00:00:00pages
36-8issue
1eissn
0027-8424issn
1091-6490journal_volume
88pub_type
杂志文章abstract::We describe a model for early onset preeclampsia (EOPE) that uses induced pluripotent stem cells (iPSCs) generated from umbilical cords of EOPE and control (CTL) pregnancies. These iPSCs were then converted to placental trophoblast (TB) representative of early pregnancy. Marker gene analysis indicated that both sets 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.1816150116
更新日期:2019-03-05 00:00:00
abstract::Naked mole-rats form eusocial colonies consisting of a single breeding female (the queen), several breeding males, and sexually immature adults (subordinates). Subordinates are cooperative and provide alloparental care by huddling and retrieving pups to the nest. However, the physiological mechanism(s) underlying allo...
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.1720530115
更新日期:2018-09-11 00:00:00
abstract::As an electron transfer-driven proton pump, cytochrome c oxidase (ferrocytochrome-c:oxygen oxidoreductase, EC 1.9.3.1) must alternate between two conformations in each valence state of the redox element associated with ion translocation. Using second derivative absorption spectroscopy, the conformation of the cytochro...
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.88.16.7281
更新日期:1991-08-15 00:00:00
abstract::Cooperation via production of common goods is found in diverse life forms ranging from viruses to social animals. However, natural selection predicts a "tragedy of the commons": Cheaters, benefiting from without producing costly common goods, are more fit than cooperators and should destroy cooperation. In an attempt ...
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.1210190109
更新日期:2012-11-20 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::Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a "critical period" for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their inn...
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.1200705109
更新日期:2012-10-16 00:00:00
abstract::Helper T (Th) cells are classified as Th1 or Th2 cells by virtue of cytokine secretion and function as mediators of cellular or humoral immunity, respectively. Cytokines also regulate the differentiation of Th cells. For example, interleukin (IL)-12 promotes Th1 and suppresses Th2 cell development, suggesting that IL-...
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.92.15.6847
更新日期:1995-07-18 00:00:00
abstract::Ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates (dNDPs). The Escherichia coli class Ia RNR uses a mechanism of radical propagation by which a cysteine in the active site of the RNR large (α2) subunit is transiently oxidized by a stable tyrosyl radical ...
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.1220691110
更新日期:2013-03-05 00:00:00
abstract::Alzheimer's disease (AD) is an irreversible neurodegenerative disorder that has a progression that is closely associated with oxidative stress. It has long been speculated that the reactive oxygen species (ROS) level in AD brains is much higher than that in healthy brains. However, evidence from living beings is scarc...
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.1706248114
更新日期:2017-11-21 00:00:00
abstract::Damage to the protooncogene MYC has been implicated in the genesis of diverse human tumors, but the tumorigenic potential of the isolated gene has been disputed. Here we report the use of a retroviral vector to test the potency of human MYC for neoplastic transformation in avian cells. We found that sustained and abun...
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.87.6.2102
更新日期:1990-03-01 00:00:00
abstract::It has recently been recognized that human serum contains a protein that specifically binds human growth hormone (hGH). This protein has the same restricted specificity for hGH as the membrane-bound GH receptor. To determine whether the GH-binding protein is a derivative of, or otherwise related to, the GH receptor, 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.84.13.4636
更新日期:1987-07-01 00:00:00
abstract::Most studies on the ability of insect populations to transmit pathogens consider only constant temperatures and do not account for realistic daily temperature fluctuations that can impact vector-pathogen interactions. Here, we show that diurnal temperature range (DTR) affects two important parameters underlying dengue...
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.1101377108
更新日期:2011-05-03 00:00:00
abstract::We demonstrate that single interneurons can toggle the output neurons of the cerebellar cortex (the Purkinje cells) between their two states. The firing of Purkinje cells has previously been shown to alternate between an "up" state in which the cell fires spontaneous action potentials and a silent "down" state. We sho...
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.1002082107
更新日期:2010-07-20 00:00:00
abstract::Dominant mutations in the maize homeobox gene knotted1 (kn1) act nonautonomously during maize leaf development, indicating that Kn1 is involved in the generation or transmission of a developmental signal that passes from the inner layers of the leaf to epidermal cells. We previously found that this nonautonomous activ...
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.052484099
更新日期:2002-03-19 00:00:00
abstract::The fate of two recently described human B lymphocyte-specific antigens (B1 and B2) was studied after B-cell activation in vivo and in vitro. Whereas both B1 and B2 were present on virtually all B cells from normal lymph nodes, B2 was absent from approximately 50% of B cells from hyperplastic lymph nodes. When B cells...
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.78.6.3848
更新日期:1981-06-01 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::Human C5a, a complement-derived anaphylatoxin, is a potent mediator of human leukocyte chemotaxis. Using a homogeneous preparation of C5a that was 125I-labeled, we have demonstrated the presence of a specific cellular receptor for this glycoprotein on intact human polymorphonuclear leukocytes. Cellular uptake of the r...
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.75.8.3943
更新日期:1978-08-01 00:00:00
abstract::We have isolated and characterized the complete human villin gene. The villin gene is located on chromosome 2q35-36 in humans and on chromosome 1 in mice. Villin belongs to a family of calcium-regulated actin-binding proteins that share structural and functional homologies. The villin gene is expressed mainly in cells...
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.88.23.10811
更新日期:1991-12-01 00:00:00
abstract::The genomes of hyperthermophilic Archaea encode dozens of methylation guide, C/D box small RNAs that guide 2'-O-methylation of ribose to specific sites in rRNA and various tRNAs. The genes encoding the Sulfolobus homologues of eukaryotic proteins that are known to be present in C/D box small nucleolar ribonucleoprotei...
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.082101999
更新日期:2002-04-16 00:00:00
abstract::Indirect reciprocity is a mechanism for cooperation based on shared moral systems and individual reputations. It assumes that members of a community routinely observe and assess each other and that they use this information to decide who is good or bad, and who deserves cooperation. When information is transmitted pub...
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.1810565115
更新日期:2018-11-27 00:00:00
abstract::Associative memory of the mollusc Hermissenda crassicornis, previously correlated with changes of specific K+ currents, protein phosphorylation, and increased synthesis of mRNA and specific proteins, is here shown to be accompanied by macroscopic alteration in the structure of a single identified neuron, the medial ty...
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.87.4.1611
更新日期:1990-02-01 00:00:00
abstract::In vertebrate retinal photoreceptors, photoisomerization of opsin-bound visual chromophore 11-cis-retinal to all-trans-retinal triggers phototransduction events. Regeneration of the chromophore is a critical step in restoring photoreceptors to their dark-adapted state. This regeneration process, called the retinoid cy...
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.0503318102
更新日期:2005-06-07 00:00:00
abstract::Tracheal antimicrobial peptide (TAP) is a member of the beta-defensin family of antibiotic peptides found in the tracheal mucosa of the cow. TAP gene expression in the bovine airway is inducible by lipopolysaccharide and inflammatory mediators, suggesting that it functions to protect the upper airway from infection. 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.93.24.14118
更新日期:1996-11-26 00:00:00
abstract::Low phosphate (Pi) availability is one of the major constraints for plant productivity in natural and agricultural ecosystems. Plants have evolved a myriad of developmental and biochemical mechanisms to increase internal Pi uptake and utilization efficiency. One important biochemical pathway leading to an increase 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.0600863103
更新日期:2006-04-25 00:00:00
abstract::Degradable polymers are beginning to play an increasing role as materials for environmental and medical applications. Understanding factors that control erosion, such as bond cleavage and the dissolution and diffusion of degradation products, will be critical to the future development of these materials. Erosion kinet...
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.90.2.552
更新日期:1993-01-15 00:00:00
abstract::The nonneural cholinergic system of immune cells is pivotal for the maintenance of immunological homeostasis. Here we demonstrate the expression of choline acetyltransferase (ChAT) and cholinergic enzymes in murine natural killer (NK) cells. The capacity for acetylcholine synthesis by NK cells increased markedly under...
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.1705491114
更新日期:2017-07-25 00:00:00
abstract::The unicellular green alga Chlamydomonas swims with two flagella that can synchronize their beat. Synchronized beating is required to swim both fast and straight. A long-standing hypothesis proposes that synchronization of flagella results from hydrodynamic coupling, but the details are not understood. Here, we presen...
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.1300895110
更新日期:2013-11-05 00:00:00
abstract::Cryogenic fluorescent light microscopy of flash-frozen cells stands out by artifact-free fixation and very little photobleaching of the fluorophores used. To attain the highest level of resolution, aberration-free immersion objectives with accurately matched immersion media are required, but both do not exist for imag...
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.1717282115
更新日期:2018-02-06 00:00:00
abstract::HetR is an essential regulator of heterocyst development in cyanobacteria. Many mutations in HetR render Anabaena incapable of nitrogen fixation. The protein binds to a DNA palindrome upstream of hetP and other genes. We have determined the crystal structures of HetR complexed with palindromic DNA targets, 21, 23, and...
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.1305971110
更新日期:2013-05-07 00:00:00
abstract::We propose that protein translocation across membranes is driven by biased random thermal motion. This "Brownian ratchet" mechanism depends on chemical asymmetries between the cis and trans sides of the membrane. Several mechanisms could contribute to rectifying the thermal motion of the protein, such as binding and 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.89.9.3770
更新日期:1992-05-01 00:00:00