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 conservative demonstration of the influences that water birds in general exert on the structure of aquatic ecosystems.
journal_name
Proc Natl Acad Sci U S Aauthors
Hurlbert SH,Chang CCdoi
10.1073/pnas.80.15.4766subject
Has Abstractpub_date
1983-08-01 00:00:00pages
4766-9issue
15eissn
0027-8424issn
1091-6490journal_volume
80pub_type
杂志文章abstract::In the mitochondrial genome of the hemichordate Balanoglossus carnosus, the codon AAA, which is assigned to lysine in most metazoans but to asparagine in echinoderms, is absent. Furthermore, the lysine tRNA gene carries an anticodon substitution that renders its gene product unable to decode AAA codons, whereas the as...
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.95.7.3703
更新日期:1998-03-31 00:00:00
abstract::Peripheral inhibitory nerves are physiological regulators of the contractile behavior of visceral smooth muscles. One of the transmitters responsible for inhibitory neurotransmission has been reputed to be a purine, possibly ATP. However, the exact identity of this substance has never been verified. Here we show 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.0705510104
更新日期:2007-10-09 00:00:00
abstract::Transforming growth factor betas (TGF-betas) regulate key aspects of embryonic development and major human diseases. Although Smad2, Smad3, and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs) have been proposed as key mediators in TGF-beta signaling, their functional specificities...
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.1834070100
更新日期:2003-09-02 00:00:00
abstract::It has been recognized since ancient times that malaria fever is highly periodic but the mechanism has been poorly understood. Malaria fever is related to the parasite growth cycle in erythrocytes. After a fixed period of replication, a mature parasite (schizont) causes the infected erythrocyte to rupture, releasing 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.88.12.5111
更新日期:1991-06-15 00:00:00
abstract::This paper shows that the most predictable components of internal variability in coupled atmosphere-ocean models are remarkably similar to the most predictable components of climate models without interactive ocean dynamics (i.e., models whose ocean is represented by a 50-m-deep slab ocean mixed layer with no interact...
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.1614085114
更新日期:2017-02-28 00:00:00
abstract::Live proliferation-competent and irradiated proliferation-incompetent L5178 murine lymphoma cells (Eb cell line) were compared for their potency to induce systemic anti-tumor immunity in syngeneic DBA/2 mice. The tumorigenic potential in vivo of live Eb cells was suppressed through local secretion of interleukin 4 (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.91.16.7430
更新日期:1994-08-02 00:00:00
abstract::Addition of a 0.5 M KCl wash fraction from rabbit reticulocyte ribosomes causes a 3- to 10-fold increase in the extent of translation of natural mRNAs by Krebs-cell lysates. In the presence of the wash fraction, 1 pmol of rabbit or mouse 10S RNA directs the incorporation of 80 pmol of leucine into rabbit globin. The 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.69.5.1299
更新日期:1972-05-01 00:00:00
abstract::We used digital fluorescence microscopy to make real-time observations of anaphase chromosome movement and changes in microtubule organization in spindles assembled in Xenopus egg extracts. Anaphase chromosome movement in these extracts resembled that seen in living vertebrate cells. During anaphase chromosomes moved ...
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.93.22.12327
更新日期:1996-10-29 00:00:00
abstract::The later stages of cochlear differentiation and the developmental onset of hearing require thyroid hormone. Although thyroid hormone receptors (TRs) are a prerequisite for this process, it is likely that other factors modify TR activity during cochlear development. The mouse cochlea expresses type 2 deiodinase (D2), ...
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.0307402101
更新日期:2004-03-09 00:00:00
abstract::Assembly of protein complexes is a key mechanism for achieving spatial and temporal coordination in processes involving many enzymes. Growth of rod-shaped bacteria is a well-studied example requiring such coordination; expansion of the cell wall is thought to involve coordination of the activity of synthetic enzymes 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.1313826111
更新日期:2014-03-25 00:00:00
abstract::Interdigital webbing has evolved repeatedly in tropical salamanders (bolitoglossines). This derived foot morphology is only one of many homoplastic traits in this diverse amphibian clade. Indeed, few if any morphological traits sort lineages within this clade. We investigate the processes underlying the homoplastic ev...
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.0710216105
更新日期:2007-12-18 00:00:00
abstract::The first step in poliovirus replication is binding of virus to a cellular receptor. Mouse L cells, which are resistant to poliovirus infection because they do not bear a poliovirus receptor, were transformed with HeLa cell (human) DNA to poliovirus sensitivity at a frequency of approximately 1 in 50,000 transformants...
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.83.20.7845
更新日期:1986-10-01 00:00:00
abstract::It has been reported that expression of familial amyotrophic lateral sclerosis (FALS)-associated mutant Cu/Zn superoxide dismutase-1 (SOD) induces apoptosis of neuronal cells in culture associated with an increase in reactive oxygen species. SOD recently has been shown to prevent calcineurin inactivation, initiating 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.96.6.3251
更新日期:1999-03-16 00:00:00
abstract::Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and effici...
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.1413325111
更新日期:2014-09-09 00:00:00
abstract::Initial attempts to correlate the distribution of gene density (number of gene loci per unit length on the linkage map) with the distribution of lengths of coding sequences have led to the observation that 46% of approximately 1000 sampled proteins in Escherichia coli have molecular masses of n X 14,000 +/- 2500 dalto...
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.83.5.1198
更新日期:1986-03-01 00:00:00
abstract::The ATP-dependent enzyme dethiobiotin synthetase from Escherichia coli catalyses the formation of dethiobiotin from CO2 and 7, 8-diaminopelargonic acid. The reaction is initiated by the formation of a carbamate and proceeds through a phosphorylated intermediate, a mixed carbamic phosphoric anhydride. Here, we report 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.95.10.5495
更新日期:1998-05-12 00:00:00
abstract::Ca2+/calmodulin-dependent protein kinase II (CaM-KII) regulates numerous physiological functions, including neuronal synaptic plasticity through the phosphorylation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors. To identify proteins that may interact with and modulate CaM-KII fun...
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.95.18.10890
更新日期:1998-09-01 00:00:00
abstract::The density of benzodiazepine/gamma-aminobutyric acid receptor binding sites was lower in the midbrain of seizure-susceptible gerbils compared to control seizure-resistant gerbils. Binding of [3H]diazepam to high-affinity brain-specific sites in membrane homogenates of gerbil brain showed a 20-30% lower binding in mid...
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.82.19.6701
更新日期:1985-10-01 00:00:00
abstract::We have developed a procedure for purifying highly specific polyclonal antibodies against 5-methylcytosine. These antibodies were used to probe the distribution of 5-methylcytosine among fractionated nucleosomes of mouse cell chromatin. Our results demonstrate that at least 80% of the 5-methylcytosine is localized 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.80.18.5490
更新日期:1983-09-01 00:00:00
abstract::Infection of mice with sporozoites of Plasmodium berghei or Plasmodium yoelii has been used extensively to evaluate liver-stage protection by candidate preerythrocytic malaria vaccines. Unfortunately, repeated success of such vaccines in mice has not translated readily to effective malaria vaccines in humans. Thus, mi...
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.0805452105
更新日期:2008-09-16 00:00:00
abstract::Secretion of extracellular polymeric substances (EPSs) by growing bacteria is an integral part of forming biofilm-like structures. In such dense systems, mechanical interactions among the structural components can be expected to significantly contribute to morphological properties. Here, we use a particle-based modeli...
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.1504948112
更新日期:2015-04-28 00:00:00
abstract::Athymic mice grafted at birth with allogeneic thymic epithelium (TE) from day 10 embryos before hematopoietic cell colonization reconstitute normal numbers of T cells and exhibit full life-long tolerance to skin grafts of the TE haplotype. Intravenous transfers of splenic cells, from these animals to adult syngeneic 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.92.16.7555
更新日期:1995-08-01 00:00:00
abstract::Chinese hamster-human somatic cell hybrids were analyzed for the expression of human galactose-1-phosphate uridyltransferase (GALT; UDPglucose:alpha-D-galactose-1-phosphate uridyltransferase, EC 2.7.7.12) by electrophoresis and for the presence of human chromosomes cytogenetically with the aid of Q-banding. Three of 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.74.12.5628
更新日期:1977-12-01 00:00:00
abstract::The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their curr...
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.1315162110
更新日期:2013-12-17 00:00:00
abstract::Dendritic cell (DC) lectins mediate the recognition, uptake, and processing of antigens, but they can also be coopted by pathogens for infection. These distinct activities depend upon the routing of antigens within the cell. Antigens directed to endosomal compartments are degraded, and the peptides are presented on ma...
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.1820165116
更新日期:2019-07-23 00:00:00
abstract::Drosophila ovo/svb (dovo) is required for epidermal cuticle/denticle differentiation and is genetically downstream of the wg signaling pathway. Similarly, a mouse homolog of dovo, movo1, is required for the proper formation of hair, a mammalian epidermal appendage. Here, we provide biochemical evidence that movo1 enco...
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.092137099
更新日期:2002-04-30 00:00:00
abstract::Saccharomyces cerevisiae is an ideal host from which to obtain high levels of posttranslationally modified eukaryotic proteins for x-ray crystallography. However, extensive replacement of methionine by selenomethionine for anomalous dispersion phasing has proven intractable in yeast. We report a general method to inco...
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.0610337104
更新日期:2007-04-17 00:00:00
abstract::When Drosophila melanogaster embryos were ligated at very early stages of nuclear multiplication (45-60 min after egg deposition) for the entire period of embryogenesis, egg fragments of variable sizes were able to continue development up to the hatching stage. These ligated embryos differentiated larval structures; 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.74.5.2050
更新日期:1977-05-01 00:00:00
abstract::Identified over a dozen years ago in the brain and pancreatic islet, βIV-spectrin is critical for the local organization of protein complexes throughout the nervous system. βIV-Spectrin targets ion channels and adapter proteins to axon initial segments and nodes of Ranvier in neurons, and βIV-spectrin dysfunction unde...
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.1314195110
更新日期:2013-10-22 00:00:00
abstract::Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a key transcriptional regulator for antioxidant and anti-inflammation enzymes that binds to its endogenous inhibitor protein, Kelch-like ECH (erythroid cell-derived protein with CNC homology)-associated protein 1, in the cytoplasm under normal conditions. Various 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.1207718109
更新日期:2012-10-23 00:00:00