全文获取类型
收费全文 | 50篇 |
免费 | 2篇 |
专业分类
52篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 7篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1989年 | 1篇 |
1942年 | 1篇 |
1940年 | 2篇 |
1937年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
1926年 | 1篇 |
1925年 | 1篇 |
1924年 | 1篇 |
排序方式: 共有52条查询结果,搜索用时 0 毫秒
1.
2.
Rust diseases cause significant reductions annually in yield of cereal crops worldwide. Traditional monoculture cropping systems apply significant selection pressure on the pathogen to cause rapid shifts in pathotypes. Plant breeders strive to stay ahead of the evolving pathogens by releasing new crop genotypes with new rust resistance genes or gene combinations. Owing to the limited number of known resistance genes and the lack of molecular understanding of the plant-pathogen interaction, rusts remain challenging organisms to study, both at organismal and molecular levels. This review discusses recent progress by a number of laboratories towards better understanding the molecular component of rust disease resistance. 相似文献
3.
Joseph B. Greer Bryan P. Early Kenneth R. Durbin Steven M. Patrie Paul M. Thomas Neil L. Kelleher Richard D. LeDuc Ryan T. Fellers 《Proteomics》2022,22(11-12):2100209
The effectiveness of any proteomics database search depends on the theoretical candidate information contained in the protein database. Unfortunately, candidate entries from protein databases such as UniProt rarely contain all the post-translational modifications (PTMs), disulfide bonds, or endogenous cleavages of interest to researchers. These omissions can limit discovery of novel and biologically important proteoforms. Conversely, searching for a specific proteoform becomes a computationally difficult task for heavily modified proteins. Both situations require updates to the database through user-annotated entries. Unfortunately, manually creating properly formatted UniProt Extensible Markup Language (XML) files is tedious and prone to errors. ProSight Annotator solves these issues by providing a graphical interface for adding user-defined features to UniProt-formatted XML files for better informed proteoform searches. It can be downloaded from http://prosightannotator.northwestern.edu . 相似文献
4.
5.
We present a comprehensive survey of genetic variation across the range of the narrowly distributed endemic Yosemite toad Bufo canorus, a declining amphibian restricted to the Sierra Nevada of California. Based on 322 bp of mitochondrial cytochrome b sequence data, we found limited support for the monophyly of B. canorus and its closely related congener B. exsul to the exclusion of the widespread western toad B. boreas. However, B. exsul was always phylogenetically nested within B. canorus, suggesting that the latter may not be monophyletic. SSCP (single-strand conformation polymorphism) analysis of 372 individual B. canorus from 28 localities in Yosemite and Kings Canyon National Parks revealed no shared haplotypes among these two regions and lead us to interpret these two parks as distinct management units for B. canorus. Within Yosemite, we found significant genetic substructure both at the level of major drainages and among breeding ponds. Kings Canyon samples show a different pattern, with substantial variation among breeding sites, but no substructure among drainages. Across the range of B. canorus as well as among Yosemite ponds, we found an isolation-by-distance pattern suggestive of a stepping stone model of migration. However, in Kings Canyon we found no hint of such a pattern, suggesting that movement patterns of toads may be quite different in these nearby parklands. Our data imply that management for B. canorus should focus at the individual pond level, and effective management may necessitate reintroductions if local extirpations occur. A brief review of other pond-breeding anurans suggests that highly structured populations are often the case, and thus that our results for B. canorus may be general for other species of frogs and toads. 相似文献
6.
Structural variation and evolution of a defense-gene cluster in natural populations of Aegilops tauschii 总被引:1,自引:0,他引:1
Brooks SA Huang L Herbel MN Gill BS Brown-Guedira G Fellers JP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(4):618-626
Genetic mapping and sequencing of plant genomes have been useful for investigating eukaryotic chromosome structural organization.
In many cases, analyses have been limited in the number of representatives sampled from specific groups. The degree of intraspecific
genome diversity remains in question. The possibility exists that a single model genome may have limited utility for identifying
genes in related members of the species or genus. Crop improvement programs have particular interests in disease resistance
genes that are harbored by wild relatives of modern cultivated crops. These genes are evolutionarily dynamic and under selective
pressure by a broad range of pathogenic organisms. Using resistance gene analogs as models for gene evolution, intraspecific
genome comparisons were made among populations of wild diploid wheat (Aegilops tauschii). We observed that deletion haplotypes are occurring frequently and independently in the genome. Haplotypes are geographically
correlated and maintenance of gene complements in localized populations indicates selective advantage. Furthermore, deletion
haplotypes are not detrimental to plant health, since genes without adaptive value in alternate environments are eliminated
from the genome. Deletion haplotypes appear to be a common form of allelic variation in plants, and we address the consequences
on genome restructuring and gene evolution.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
7.
Amy J. Lind Phillip Q. Spinks Gary M. Fellers H. Bradley Shaffer 《Conservation Genetics》2011,12(1):269-284
Genetic data are increasingly being used in conservation planning for declining species. We sampled both the ecological and
distributional limits of the foothill yellow-legged frog, Rana boylii to characterize mitochondrial DNA (mtDNA) variation in this declining, riverine amphibian. We evaluated 1525 base pairs (bp)
of cytochrome b and ND2 fragments for 77 individuals from 34 localities using phylogenetic and population genetic analyses. We constructed
gene trees using maximum likelihood and Bayesian inference, and quantified genetic variance (using AMOVA and partial Mantel
tests) within and among hydrologic regions and river basins. Several moderately supported, geographically-cohesive mtDNA clades
were recovered for R. boylii. While genetic variation was low among populations in the largest, most inclusive clade, samples from localities at the edges
of the geographic range demonstrated substantial genetic divergence from each other and from more central populations. Hydrologic
regions and river basins, which represent likely dispersal corridors for R. boylii, accounted for significant levels of genetic variation. These results suggest that both rivers and larger hydrologic and geographic
regions should be used in conservation planning for R. boylii. 相似文献
8.
Vast differences exist in genome sizes of higher plants; however, gene count remains relatively constant among species. Differences observed in DNA content can be attributed to retroelement amplification leading to genome expansion. Cytological and genetic studies have demonstrated that genes are clustered in islands rather than distributed at random in the genome. Analysis of gene islands within highly repetitive genomes of plants like wheat remains largely unstudied. The objective of our work was to sequence and characterize a contiguous DNA sequence from chromosome IDS of Aegilops tauschii. An RFLP probe that maps to the Lr21 region of IDS was used to isolate a single BAC. The BAC was sequenced and is 106 kb in length. The contiguous DNA sequence contains a 46-kb retroelement-free gene island containing seven coding sequences. Within the gene island is a complex arrangement of resistance and defense response genes. Overall gene density in this BAC is 1 gene per 8.9 kb. This report demonstrates that wheat and its relatives do contain regions with gene densities similar to that of Arabidopsis. 相似文献
9.
Crocker DE Kofahl N Fellers GD Gates NB Houser DS 《Physiological and biochemical zoology : PBZ》2007,80(6):635-642
We measured water flux and energy expenditure in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea by using the doubly labeled water method. Previous laboratory investigations have suggested weak urinary concentrating ability, high rates of water flux, and low basal metabolic rates in this species. However, free-ranging measurements from hygric mammals are rare, and it is not known how these features interact in the environment. Rates of water flux (210+/-32 mL d(-1)) and field metabolic rates (1,488+/-486 kJ d(-1)) were 159% and 265%, respectively, of values predicted by allometric equations for similar-sized herbivores. Mountain beavers can likely meet their water needs through metabolic water production and preformed water in food and thus remain in water balance without access to free water. Arginine-vasopressin levels were strongly correlated with rates of water flux and plasma urea : creatinine ratios, suggesting an important role for this hormone in regulating urinary water loss in mountain beavers. High field metabolic rates may result from cool burrow temperatures that are well below lower critical temperatures measured in previous laboratory studies and suggest that thermoregulation costs may strongly influence field energetics and water flux in semifossorial mammals. 相似文献
10.