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排序方式: 共有1084条查询结果,搜索用时 218 毫秒
41.
Alex A. Pollen Aparna Bhaduri Madeline G. Andrews Tomasz J. Nowakowski Olivia S. Meyerson Mohammed A. Mostajo-Radji Elizabeth Di Lullo Beatriz Alvarado Melanie Bedolli Max L. Dougherty Ian T. Fiddes Zev N. Kronenberg Joe Shuga Anne A. Leyrat Jay A. West Marina Bershteyn Craig B. Lowe Bryan J. Pavlovic Arnold R. Kriegstein 《Cell》2019,176(4):743-756.e17
42.
Manipulation of endogenous trypsin proteinase inhibitor production in Nicotiana attenuata demonstrates their function as antiherbivore defenses 总被引:9,自引:0,他引:9
Evidence for the in planta defensive function of trypsin protease inhibitors (TPIs) comes from observations of enhanced herbivore resistance after heterologous TPI expression or the manipulation of signal cascades that activate numerous defense responses, including TPI production; no studies have altered the expression of an endogenous pi gene to examine defensive function. We isolated two genes with seven- and six-repeat TPI domains from Nicotiana attenuata from the potato (Solanum tuberosum) PI-II family. To determine whether endogenous TPIs in N. attenuata function defensively against the native herbivores, hornworm (Manduca sexta) and mirids (Tupiocoris notatus), we expressed 175 bp of the seven-domain pi from N. attenuata in an antisense orientation in a TPI-producing genotype to reduce TPI expression and expressed the full-length seven-domain pi in a sense orientation under control of a constitutive promoter to restore TPI activity in a natural genotype from Arizona unable to produce TPIs. Constitutive and inducible TPI production in two antisense lines were diminished by 80% to 90% and 33% to 52%, respectively, and sense expression restored 67% of the activity found in the TPI-producing genotype after caterpillar attack in the TPI-deficient A genotype. Hornworm larvae fed on genotypes with low or no TPI activity grew faster, had higher survivorship, and produced heavier pupae than those that fed on genotypes with high TPI activity. T. notatus showed higher preference for genotypes with low or no TPI activity than for genotypes with high TPI levels. We conclude that endogenous TPIs are an effective defense against these native herbivores. 相似文献
43.
Oxidative modification of hepatic mitochondria protein thiols: effect of chronic alcohol consumption
Venkatraman A Landar A Davis AJ Ulasova E Page G Murphy MP Darley-Usmar V Bailey SM 《American journal of physiology. Gastrointestinal and liver physiology》2004,286(4):G521-G527
Redox modification of mitochondrial proteins is thought to play a key role in regulating cellular function, although direct evidence to support this hypothesis is limited. Using an in vivo model of mitochondrial redox stress, ethanol hepatotoxicity, the modification of mitochondrial protein thiols was examined using a proteomics approach. Specific labeling of reduced thiols in the mitochondrion from the livers of control and ethanol-fed rats was achieved by using the thiol reactive compound (4-iodobutyl)triphenylphosphonium (IBTP). This molecule selectively accumulates in the organelle and can be used to identify thiol-containing proteins. Mitochondrial proteins that have been modified are identified by decreased labeling with IBTP using two-dimensional SDS-PAGE followed by immunoblotting with an antibody directed against the triphenylphosphonium moiety of the IBTP molecule. Analyses of these data showed a significant decrease in IBTP labeling of thiols present in specific mitochondria matrix proteins from ethanol-fed rats compared with their corresponding controls. These proteins were identified as the low-K(m) aldehyde dehydrogenase and glucose-regulated protein 78. The decrease in IBTP labeling in aldehyde dehydrogenase was accompanied by a decrease in specific activity of the enzyme. These data demonstrate that mitochondrial protein thiol modification is associated with chronic alcohol intake and might contribute to the pathophysiology associated with hepatic injury. Taken together, we have developed a protocol to chemically tag and select thiol-modified proteins that will greatly enhance efforts to establish posttranslational redox modification of mitochondrial protein in in vivo models of oxidative or nitrosative stress. 相似文献
44.
Direct differentiation of somatic embryos occurs in high-frequency and at high density in response to 1.0 microM TDZ, on different regions-hypocotyl, epicotyl, cotyledonary-node, cotyledons and leaves-of intact seedlings of Azadirachta. One-week-old seedlings on this medium exhibited stress symptoms as visible by the loss of root formation and reduction in the elongation of hypocotyl and epicotyl. Globular somatic embryos were more abundant on hypocotyl, epicotyl, stem tip and leaves. The arrest of embryos at this stage was possibly due to their presence in high density. Well-developed somatic embryos were present on the cotyledons and the cotyledonary-node. These embryos on isolation and transfer to hormone-free medium regenerated readily to form plantlets. The possible role of stress in thidiazuron-induced somatic embryo formation is discussed. 相似文献
45.
In Population Genetics, two populations are distinguished from each other on the basis of the differences in the distributions
of the alleles at the locus or loci under consideration. These differences are measured by a “genetic distance” between the
two populations (not to be confused with genetic distance between two loci, which is based on recombination fractions) and
they play a major role in inferences at the population level. Several measures of genetic distance have been proposed by different
authors (Sanghvi 1953; Cavalli-Sforza and Edwards 1967; Jukes and Cantor 1969; Nei 1972; Kimura 1980; Reynoldset al 1983; reviews in Felsenstein 1991; Nei and Kumar 2000). Most of these measures are actually dissimilarity measures and not
mathematically true distance measures (B-Rao and Majumdar 1999). Independently, and much before the geneticists, statisticians
too were concerned with the idea of distinguishing between two (statistical) populations. In order to discriminate between
two populations on the basis of one or more characters, divergence measures like “Mahalanobis’D
2 statistic” or “Mahalanobis’ generalized distance” (1936) and “Bhattacharyya’s distance” (1943, 1946), Kullback-Leibler’s
divergence measure (1951) etc. have been proposed by statisticians. Mukherjee and Chattopadhyaya (1986) have mentioned measures
based on distances, association between two attributes and discrimination function. There are similarities between the distance
measures defined by applied scientists and by theoreticians. Felsenstein (1985) shows that three of the allele frequency-based
genetic distance measures were anticipated by Bhattacharyya (1946). Nei and Takezaki (1994) have also studied the effectiveness
of several genetic distance measures in the context of phylogenetic analysis, including Bhattacharyya’s distance measure. 相似文献
46.
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48.
Zhang H Berg JS Li Z Wang Y Lång P Sousa AD Bhaskar A Cheney RE Strömblad S 《Nature cell biology》2004,6(6):523-531
Unconventional myosins are actin-based motors with a growing number of attributed functions. Interestingly, it has been proposed that integrins are transported by unidentified myosins to facilitate cellular remodelling. Here we present an interaction between the unconventional myosin-X (Myo10) FERM (band 4.1/ezrin/radixin/moesin) domain and an NPXY motif within beta-integrin cytoplasmic domains. Importantly, knock-down of Myo10 by short interfering RNA impaired integrin function in cell adhesion, whereas overexpression of Myo10 stimulated the formation and elongation of filopodia in an integrin-dependent manner and relocalized integrins together with Myo10 to the tips of filopodia. This integrin relocalization and filopodia elongation did not occur with Myo10 mutants deficient in integrin binding or with a beta(1)-integrin point mutant deficient in Myo10 binding. Taken together, these results indicate that Myo10-mediated relocalization of integrins might serve to form adhesive structures and thereby promote filopodial extension. 相似文献
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