Abstract:
:The spatial distribution of plant defenses within a leaf may be critical in explaining patterns of herbivory. The generalist lepidopteran larvae, Helicoverpa armigera (the cotton bollworm), avoided the midvein and periphery of Arabidopsis thaliana rosette leaves and fed almost exclusively on the inner lamina. This feeding pattern was attributed to glucosinolates because it was not evident in a myrosinase mutant that lacks the ability to activate glucosinolate defenses by hydrolysis. To measure the spatial distribution of glucosinolates in A. thaliana leaves at a fine scale, we constructed ion intensity maps from MALDI-TOF (matrix assisted laser desorption/ionization-time of flight) mass spectra. The major glucosinolates were found to be more abundant in tissues of the midvein and the periphery of the leaf than the inner lamina, patterns that were validated by HPLC analyses of dissected leaves. In addition, there were differences in the proportions of the three major glucosinolates in different leaf regions. Hence, the distribution of glucosinolates within the leaf appears to control the feeding preference of H. armigera larvae. The preferential allocation of glucosinolates to the periphery may play a key role in the defense of leaves by creating a barrier to the feeding of chewing herbivores that frequently approach leaves from the edge.
journal_name
Proc Natl Acad Sci U S Aauthors
Shroff R,Vergara F,Muck A,Svatos A,Gershenzon Jdoi
10.1073/pnas.0711730105subject
Has Abstractpub_date
2008-04-22 00:00:00pages
6196-201issue
16eissn
0027-8424issn
1091-6490pii
0711730105journal_volume
105pub_type
杂志文章abstract::The second critical endpoint in the basalt-H(2)O system was directly determined by a high-pressure and high-temperature X-ray radiography technique. We found that the second critical endpoint occurs at around 3.4 GPa and 770 °C (corresponding to a depth of approximately 100 km in a subducting slab), which is much shal...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1010968108
更新日期:2011-05-17 00:00:00
abstract::The pattern of neurodegeneration in Alzheimer's disease (AD) is very distinctive: neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau selectively affect pyramidal neurons of the aging association cortex that interconnect extensively through glutamate synapses on dendritic spines. In contrast, primary se...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1322360111
更新日期:2014-04-01 00:00:00
abstract::In recent years, the field of psychology has begun to conduct replication tests on a large scale. Here, we show that "replicator degrees of freedom" make it far too easy to obtain and publish false-negative replication results, even while appearing to adhere to strict methodological standards. Specifically, using data...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2019-12-17 00:00:00
abstract::beta 1-Adrenergic receptors from turkey erythrocyte membranes have been identified by specific binding of the radiolabeled antagonist (-)-[3H]dihydroalprenolol. These receptors are inactivated by the alkylating agent N-ethylmaleimide when occupied by beta-adrenergic agonists but not when occupied by antagonists or whe...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1980-07-01 00:00:00
abstract::Many nearshore fish and invertebrate populations are overexploited even when apparently coherent management structures are in place. One potential cause of mismanagement may be a poor understanding and accounting of stochasticity, particularly for stock recruitment. Many of the fishes and invertebrates that comprise n...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-07-01 00:00:00
abstract::Wnt/beta-catenin signaling inhibits adipogenesis. Genome-wide profiling studies have revealed the enrichment of histone H3K27 methyltransferase Ezh2 on Wnt genes. However, the functional significance of such a direct link between the two types of developmental regulators in mammalian cells, and the role of Ezh2 in adi...
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更新日期:2010-04-20 00:00:00
abstract::Earlier we have shown that oscillations with a long period ("supercycles") may arise in two-locus systems experiencing cyclical selection with a short period. However, this mode of complex limiting behavior appeared to be possible for narrow ranges of parameters. Here we demonstrate that a multilocus system subjected ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1996-06-25 00:00:00
abstract::The swelling of secretory vesicles has been implicated in exocytosis, but the underlying mechanism of vesicle swelling remains largely unknown. Zymogen granules (ZGs), the membrane-bound secretory vesicles in exocrine pancreas, swell in response to GTP mediated by a G(alpha)i3 protein. Evidence is presented here that ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2002-04-02 00:00:00
abstract::Glucocorticoids are commonly used antiinflammatory agents whose use is limited by side effects. We have developed a series of glucocorticoid receptor (GR) ligands that retain the strong antiinflammatory activity of conventional glucocorticoids with reduced side effects. We present a compound, LGD5552, that binds the r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2007-12-04 00:00:00
abstract::The c-ras family is a set of c-onc genes that are highly conserved in vertebrates. The genes in this family are homologous to the transforming genes of Harvey and Kirsten murine sarcoma viruses (v-Ha-ras and v-Ki-ras, respectively). Using an in situ molecular hybridization method, we detected three sites on the human ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-08-01 00:00:00
abstract::Fanconi anemia (FA) is caused by defects in cellular responses to DNA crosslinking damage and replication stress. Given the constant occurrence of endogenous DNA damage and replication fork stress, it is unclear why complete deletion of FA genes does not have a major impact on cell proliferation and germ-line FA patie...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2020-12-29 00:00:00
abstract::Maternal microchimerism (MMc) has been associated with development of allospecific transplant tolerance, antitumor immunity, and cross-generational reproductive fitness, but its mode of action is unknown. We found in a murine model that MMc caused exposure to the noninherited maternal antigens in all offspring, but in...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2017-01-31 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1997-03-18 00:00:00
abstract::Reports differ as to whether reconstitution of telomerase activity alone is sufficient for immortalization of different types of human somatic cells or whether additional activities encoded by other "immortalizing" genes are also required. Here we show that ectopic expression of either the catalytic subunit of human t...
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abstract::Full activation of T cells requires signaling through the T-cell antigen receptor (TCR) and additional surface molecules interacting with ligands on the antigen-presenting cell. TCR recognition of agonist ligands in the absence of accessory signals frequently results in the induction of a state of unresponsiveness ter...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1996-09-03 00:00:00
abstract::The outer membrane (OM) of Gram-negative bacteria is a permeability barrier and an intrinsic antibiotic resistance factor. Lipoproteins are OM components that function in cell wall synthesis, diverse secretion systems, and antibiotic efflux pumps. Moreover, each of the essential OM machines that assemble the barrier r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2017-05-02 00:00:00
abstract::It has often been suggested that the frequently observed Watson-Crick base-pair compensatory substitutions in RNA helical structures occur mainly through a slightly deleterious G.U intermediate state. We have scored base substitutions in a set of 82 related Drosophila species for the D1 and D2 variable domains of the ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1991-11-15 00:00:00
abstract::Our recent studies have shown that deregulated expression of R2, the rate-limiting component of ribonucleotide reductase, enhances transformation and malignant potential by cooperating with activated oncogenes. We now demonstrate that the R1 component of ribonucleotide reductase has tumor-suppressing activity. Stable ...
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更新日期:1997-11-25 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::Two photochromic activators of the electrogenic membrane of the electroplax of Electrophorus electricus are described. Trans-3,3'-bis[alpha-(trimethylammonium)methyl]azobenzene dibromide (Bis-Q), one of the most potent ever reported, is active at concentrations of less than 10(-7) M. Its cis isomer, which is obtained ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2013-09-03 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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abstract::The response of nerve cells to synaptic inputs and the propagation of this activation is critically dependent on the cell-surface distribution of ion channels. In the hippocampus, Ca2+ influx through N-methyl-D-aspartate receptors (NMDAR) and/or voltage-dependent calcium channels on dendrites is thought to be critical...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1993-08-15 00:00:00
abstract::Plasma levels of corticosterone are often used as a measure of "stress" in wild animal populations. However, we lack conclusive evidence that different stress levels reflect different survival probabilities between populations. Galápagos marine iguanas offer an ideal test case because island populations are affected d...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2001-06-19 00:00:00
abstract::The Escherichia coli flagellar motor senses the intracellular concentration of the response regulator CheY-P and responds by varying the bias between its counterclockwise (CCW) and clockwise (CW) rotational states. The response is ultrasensitive with a large Hill coefficient (approximately 10). Recently, the detailed ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-08-19 00:00:00
abstract::Circadian timekeeping by intracellular molecular clocks is evident widely in prokaryotes and eukaryotes. The clockworks are driven by autoregulatory feedback loops that lead to oscillating levels of components whose maxima are in fixed phase relationships with one another. These phase relationships are the key metric ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2017-04-04 00:00:00
abstract::Color and black and white line stimulation produce qualitatively and quantitatively different 2-deoxy[14C]glucose column patterns in the striate cortex of macaque monkeys. Microdensitometry of these stimulus-dependent columns reveals interlaminar density differences that serve as a signature for the stimulus condition...
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.79.21.6722
更新日期:1982-11-01 00:00:00
abstract::Despite decades of declining crime rates, longstanding tensions between police and the public continue to frustrate the formation of cooperative relationships necessary for the function of the police and the provision of public safety. In response, policy makers continue to promote community-oriented policing (COP) an...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,随机对照试验
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更新日期:2019-10-01 00:00:00
abstract::Both polarities of the satellite RNA of tobacco ringspot virus are sources of self-cleaving sequences. RNA of the less abundant, negative polarity, designated sTobRV-(-)RNA, has cleaving activity that was mapped previously to two noncontiguous regions of the polyribonucleotide chain. Endoribonucleolytic oligoribonucle...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1990-04-01 00:00:00