Abstract:
:A remarkable property of tetrapod bone is its ability to detect and remodel areas where damage has accumulated through prolonged use. This process, believed vital to the long-term health of bone, is considered to be initiated and orchestrated by osteocytes, cells within the bone matrix. It is therefore surprising that most extant fishes (neoteleosts) lack osteocytes, suggesting their bones are not constantly repaired, although many species exhibit long lives and high activity levels, factors that should induce considerable fatigue damage with time. Here, we show evidence for active and intense remodeling occurring in the anosteocytic, elongated rostral bones of billfishes (e.g., swordfish, marlins). Despite lacking osteocytes, this tissue exhibits a striking resemblance to the mature bone of large mammals, bearing structural features (overlapping secondary osteons) indicating intensive tissue repair, particularly in areas where high loads are expected. Billfish osteons are an order of magnitude smaller in diameter than mammalian osteons, however, implying that the nature of damage in this bone may be different. Whereas billfish bone material is as stiff as mammalian bone (unlike the bone of other fishes), it is able to withstand much greater strains (relative deformations) before failing. Our data show that fish bone can exhibit far more complex structure and physiology than previously known, and is apparently capable of localized repair even without the osteocytes believed essential for this process. These findings challenge the unique and primary role of osteocytes in bone remodeling, a basic tenet of bone biology, raising the possibility of an alternative mechanism driving this process.
journal_name
Proc Natl Acad Sci U S Aauthors
Atkins A,Dean MN,Habegger ML,Motta PJ,Ofer L,Repp F,Shipov A,Weiner S,Currey JD,Shahar Rdoi
10.1073/pnas.1412372111subject
Has Abstractpub_date
2014-11-11 00:00:00pages
16047-52issue
45eissn
0027-8424issn
1091-6490pii
1412372111journal_volume
111pub_type
杂志文章abstract::When an unusually high frequency of an allele is encountered in a population, "founder effect" is often invoked as an explanation. As usually used, the term implies the disproportionate increase through chance (rather than selection) of an allele contributed to the population by a particular ancestor. While genetic th...
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.75.3.1442
更新日期:1978-03-01 00:00:00
abstract::DNA sequences in Neurospora crassa that code for ribosomal RNA have been isolated in a highly purified state by DNA-RNA hybridization. About 100 separate ribosomal RNA genes exist in each nucleus. These genes are composed of repeated sequences that are present about 100 times per nucleus. The individual members of thi...
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.69.11.3256
更新日期:1972-11-01 00:00:00
abstract::Glutamate transport by the excitatory amino acid carrier EAAC1 is known to be reversible. Thus, glutamate can either be taken up into cells, or it can be released from cells through reverse transport, depending on the electrochemical gradient of the co- and countertransported ions. However, it is unknown how fast 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.0704570104
更新日期:2007-11-13 00:00:00
abstract::Chromatin boundaries or insulators modulate enhancer-promoter interactions in complex genetic loci. However, the mechanism underlying insulator activity is not known. Previous studies showed that the activity of the Drosophila suHw insulator is abolished by the tandem arrangement (pairing) of the insulator elements, 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.0830190100
更新日期:2003-04-29 00:00:00
abstract::As part of a study into the molecular basis of attenuation and reversion to neurovirulence in the Sabin poliovirus vaccines, we have determined the complete nucleotide sequence of a cloned DNA copy of the genome of P3/Leon/37, the neurovirulent progenitor of the type 3 Sabin vaccine strain, P3/Leon 12a1b. Comparison 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.81.5.1539
更新日期:1984-03-01 00:00:00
abstract::P elements, a class of mobile genetic elements that cause hybrid dysgenesis in Drosophila melanogaster, have thus far been shown to occur only in this species. Using whole genome blot analysis, we present evidence which indicates that sequences homologous to D. melanogaster P elements also occur in Drosophila paulisto...
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.81.21.6794
更新日期:1984-11-01 00:00:00
abstract::Microinjection of plasmids encoding human tau (htau) protein into identified lamprey reticulospinal neurons (anterior bulbar cells, or ABCs) in situ induces chronic htau expression. htau protein is transported to both the axon and dendrites of expressing ABCs by mechanisms that require the C-terminal domain of htau pr...
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.94.9.4733
更新日期:1997-04-29 00:00:00
abstract::MicroRNAs (miRNAs) are small, 18-22 nt long, noncoding RNAs that act as potent negative gene regulators in a variety of physiological and pathological processes. To repress gene expression, miRNAs are packaged into RNA-induced silencing complexes (RISCs) that target mRNAs for degradation and/or translational repressio...
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.1408037111
更新日期:2014-07-01 00:00:00
abstract::Triglyceridemic response to a standard oral fat meal was determined in 28 healthy subjects and related to the levels of several lipids, lipoproteins, and apolipoproteins in the post-absorptive plasma. A fatty test meal was administered orally, and postprandial plasma triglyceride levels were determined. In the fasting...
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.80.5.1449
更新日期:1983-03-01 00:00:00
abstract::The immune defense against viral infections involves cytotoxic T lymphocytes that recognize viral products in the context of class I major histocompatibility complex (MHC) antigens. To evade such immune surveillance viruses may have evolved various strategies to manipulate the expression of class I antigens. Adenoviru...
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.83.24.9665
更新日期:1986-12-01 00:00:00
abstract::An enzyme that catalyzes the conversion of bovine proinsulin to insulin has been purified from a bovine pancreatic extract. The product of conversion was identified as insulin by aminoacid analysis and determination of carboxyl terminal aminoacid residues. The purified enzyme preparation showed one major protein band ...
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.68.6.1312
更新日期:1971-06-01 00:00:00
abstract::Several hypolipidemic drugs and certain industrial plasticizers induce proliferation of peroxisomes, enhance the activity of peroxisome-associated beta-oxidation of fatty acids, and produce hepatocellular carcinomas in the livers of rodents. Because these chemicals themselves are not mutagens and do not covalently mod...
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.81.24.7827
更新日期:1984-12-01 00:00:00
abstract::Oligosaccharide moieties of cell-surface glycoconjugates are thought to be involved in recognition events associated with tumor metastasis and invasion. Using swainsonine (SW), an inhibitor of Golgi alpha-mannosidase II that results in the formation of hybrid-type oligosaccharides on N-linked glycoproteins, we have te...
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.83.6.1752
更新日期:1986-03-01 00:00:00
abstract::Cumulative distributions of the number of doublings undergone by mixed megakaryocytic/erythroblastic colonies and by pure megakaryocytic colonies were determined from plasma clot cultures of bone marrow (from C57BL/6 mice) supplemented with erythropoietin. Analysis of these distributions suggests that these colonies 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.79.14.4410
更新日期:1982-07-01 00:00:00
abstract::Senescent cell antigen (SCA), an aging antigen, is a protein that appears on old cells and marks them for removal by the immune system in mammals. It is derived from band 3, a ubiquitous membrane transport protein found in diverse cell types and tissues. We have used synthetic peptides to identify aging antigenic site...
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.87.15.5734
更新日期:1990-08-01 00:00:00
abstract::The impacts of global climate change on different aspects of humanity's diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into acco...
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.1222471110
更新日期:2014-03-04 00:00:00
abstract::A metabolic mechanism for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris has been proposed on the basis of biochemical analyses of glucose metabolism. There was a strong correlation between glucose consumption and oxalate production. Oxalic acid was found to accumulate in the culture f...
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.191389598
更新日期:2001-09-25 00:00:00
abstract::The primary structure of the Escherichia coli hemolysin polypeptide (HlyA) is used to predict intramolecular structures involved in the secretion and cytolytic activity of the molecule. The C-terminal region of HlyA contains a repeated, 8-amino acid chain represented by the consensus sequence Leu-Xaa-Gly-Gly-Xaa-Gly-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.85.14.5269
更新日期:1988-07-01 00:00:00
abstract::The fluorescence decay functions of individual, specifically labeled tRNAPhe molecules exhibit nonexponential character as a result of conformational dynamics occurring during the measurement on a single molecule. tRNAPhe conformational states that interchange much more slowly are evidenced by the distribution of life...
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.94.15.7932
更新日期:1997-07-22 00:00:00
abstract::Levels of inter-male aggression, both in laboratory encounters and in the field, rise dramatically during the breeding season, closely paralleling the seasonal rise in testosterone. However, post-pubertally castrated males also show the dramatic seasonal rise in aggression in laboratory encounters with castrated oppon...
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.81.16.5255
更新日期:1984-08-01 00:00:00
abstract::Tripartite motif 39 (Trim39) is a RING domain-containing E3 ubiquitin ligase able to inhibit the anaphase-promoting complex (APC/C) directly. Through analysis of Trim39 function in p53-positive and p53-negative cells, we have found, surprisingly, that p53-positive cells lacking Trim39 could not traverse the G1/S trans...
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.1212047110
更新日期:2012-12-18 00:00:00
abstract::The numbers and proportion of neurons in areas and regions of cortex were determined for a single cortical hemisphere from two prosimian galagos, one New World owl monkey, one Old World macaque monkey, and one baboon. The results suggest that there is a common plan of cortical organization across the species examined ...
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.1010356107
更新日期:2010-09-07 00:00:00
abstract::Injection of antisense oligonucleotides was used to investigate the function of c-mos in murine oocytes. Oocytes injected with antisense c-mos oligonucleotides completed the first meiotic division but failed to initiate meiosis II. Instead, loss of c-mos function led to chromosome decondensation, reformation of a nucl...
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.86.18.7038
更新日期:1989-09-01 00:00:00
abstract::Fibroblasts can condense a hydrated collagen lattice to a tissue-like structure 1/28th the area of the starting gel in 24 hr. The rate of the process can be regulated by varying the protein content of the lattice, the cell number, or the concentration of an inhibitor such as Colcemid. Fibroblasts of high population do...
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.76.3.1274
更新日期:1979-03-01 00:00:00
abstract::The accuracy of the 3'-end processing by cleavage and polyadenylation is essential for mRNA biogenesis and transcription termination. In yeast, two poorly conserved neighboring elements upstream of cleavage sites are important for accuracy and efficiency of this process. These two RNA sequences are recognized by 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.1214102110
更新日期:2012-12-26 00:00:00
abstract::Cytotoxic T lymphocytes (CTLs) recognize antigens in the context of major histocompatibility complex (MHC) class I gene products. The T-cell receptor (TCR) that mediates this MHC-restricted antigen recognition recognizes short peptide fragments rather than the intact antigen. Presentation of peptides to the TCR may th...
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.86.2.617
更新日期:1989-01-01 00:00:00
abstract::Stability of the long noncoding-polyadenylated nuclear (PAN) RNA from Kaposi's sarcoma-associated herpesvirus is conferred by an expression and nuclear retention element (ENE). The ENE protects PAN RNA from a rapid deadenylation-dependent decay pathway via formation of a triple helix between the U-rich internal loop 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.1217338109
更新日期:2012-11-20 00:00:00
abstract::Urea (200-400 milliosmolar) activates transcription, translation of, and trans-activation by the immediate-early gene transcription factor Egr-1 in a renal epithelial cell-specific fashion. The effect at the transcriptional level has been attributed to multiple serum response elements and their adjacent Ets motifs loc...
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.93.20.11242
更新日期:1996-10-01 00:00:00
abstract::Calmodulin (CaM) is a second messenger protein that has evolved to bind tightly to a variety of targets and, as such, exhibits low binding specificity. We redesigned CaM by using a computational protein design algorithm to improve its binding specificity for one of its targets, smooth muscle myosin light chain kinase ...
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.2234277100
更新日期:2003-11-11 00:00:00
abstract::Members of the tumor necrosis factor receptor (TNFR) superfamily are important for cell growth and survival. In addition to providing costimulatory signals for cell proliferation, ligation of both TNFR1 and Fas can result in programmed cell death or apoptosis. The underlying mechanism requires an intact 80-aa stretch ...
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.94.12.6346
更新日期:1997-06-10 00:00:00