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排序方式: 共有4204条查询结果,搜索用时 15 毫秒
1.
几种沙漠地区野生药用植物资源及其引种栽培   总被引:3,自引:0,他引:3  
几种沙漠地区野生药用植物资源及其引种栽培尹林克(中国科学院吐鲁番沙漠植物园,新疆吐鲁番838008)Resourcesofseveralspeciesofwildmedicinalplantsindesertregionandtheirintrodu...  相似文献   
2.
The noncoding region between tRNAPro and the large conserved sequence block is the most variable region in the mammalian mitochondrial DNA D-loop region. This variable region (ca. 270 bp) of four species of Equus, including Mongolian and Japanese native domestic horses as well as Przewalskii's (or Mongolian) wild horse, were sequenced. These data were compared with our recently published Thoroughbred horse mitochondrial DNA sequences. The evolutionary rate of this region among the four species of Equus was estimated to be 2–4 × 10–8 per site per year. Phylogenetic trees of Equus species demonstrate that Przewalskii's wild horse is within the genetic variation among the domestic horse. This suggests that the chromosome number change (probably increase) of the Przewalskii's wild horse occurred rather recently.Correspondence to: N. Ishida  相似文献   
3.
We have previously shown that phospholipase D (PLD) pathways have a role in neuronal degeneration; in particular, we found that PLD activation is associated with synaptic injury induced by oxidative stress. In the present study, we investigated the effect of α-synuclein (α-syn) overexpression on PLD signaling. Wild Type (WT) α-syn was found to trigger the inhibition of PLD1 expression as well as a decrease in ERK1/2 phosphorylation and expression levels. Moreover, ERK1/2 subcellular localization was shown to be modulated by WT α-syn in a PLD1-dependent manner. Indeed, PLD1 inhibition was found to alter the neurofilament network and F-actin distribution regardless of the presence of WT α-syn. In line with this, neuroblastoma cells expressing WT α-syn exhibited a degenerative-like phenotype characterized by a marked reduction in neurofilament light subunit (NFL) expression and the rearrangement of the F-actin organization, compared with either the untransfected or the empty vector-transfected cells. The gain of function of PLD1 through the overexpression of its active form had the effect of restoring NFL expression in WT α-syn neurons. Taken together, our findings reveal an unforeseen role for α-syn in PLD regulation: PLD1 downregulation may constitute an early mechanism in the initial stages of WT α-syn-triggered neurodegeneration.  相似文献   
4.
Glycine latifolia (Benth.) Newell & Hymowitz (2= 40), one of the 27 wild perennial relatives of soybean, possesses genetic diversity and agronomically favorable traits that are lacking in soybean. Here, we report the 939‐Mb draft genome assembly of G. latifolia (PI 559298) using exclusively linked‐reads sequenced from a single Chromium library. We organized scaffolds into 20 chromosome‐scale pseudomolecules utilizing two genetic maps and the Glycine max (L.) Merr. genome sequence. High copy numbers of putative 91‐bp centromere‐specific tandem repeats were observed in consecutive blocks within predicted pericentromeric regions on several pseudomolecules. No 92‐bp putative centromeric repeats, which are abundant in G. max, were detected in G. latifolia or Glycine tomentella. Annotation of the assembled genome and subsequent filtering yielded a high confidence gene set of 54 475 protein‐coding loci. In comparative analysis with five legume species, genes related to defense responses were significantly overrepresented in Glycine‐specific orthologous gene families. A total of 304 putative nucleotide‐binding site (NBS)‐leucine‐rich‐repeat (LRR) genes were identified in this genome assembly. Different from other legume species, we observed a scarcity of TIR‐NBS‐LRR genes in G. latifolia. The G. latifolia genome was also predicted to contain genes encoding 367 LRR‐receptor‐like kinases, a family of proteins involved in basal defense responses and responses to abiotic stress. The genome sequence and annotation of G. latifolia provides a valuable source of alternative alleles and novel genes to facilitate soybean improvement. This study also highlights the efficacy and cost‐effectiveness of the application of Chromium linked‐reads in diploid plant genome de novo assembly.  相似文献   
5.
中国燕麦种质资源国外引种与利用   总被引:3,自引:0,他引:3  
综述了中国从国外引进燕麦种质资源及其利用情况。经过长期努力,中国从28个国家引进29个物种的燕麦种质资源共计2099份,大大增加了中国燕麦种质资源的数量,丰富了中国保存燕麦种质资源的物种和遗传多样性。与此同时,利用国外燕麦种质资源改良和培育出了一批优良品种,极大地提高了中国燕麦生产水平。利用引进的燕麦野生资源,开展了燕麦种质创新、起源进化和遗传学研究,取得了显著进展。建议继续加强国外燕麦种质资源的引进,对野生燕麦进行深入鉴定评价和利用,同时加强燕麦种质资源国际合作研究。  相似文献   
6.
Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. We predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistance and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients.  相似文献   
7.

Background

AHSP is an erythroid molecular chaperone of the α-hemoglobin chains (α-Hb). Upon AHSP binding, native ferric α-Hb undergoes an unprecedented structural rearrangement at the heme site giving rise to a 6th coordination bond with His(E7).

Methods

Recombinant AHSP, WT α-Hb:AHSP and α-HbHE7Q:AHSP complexes were expressed in Escherichia coli. Thermal denaturation curves were measured by circular dichroism for the isolated α-Hb and bound to AHSP. Kinetics of ligand binding and redox reactions of α-Hb bound to AHSP as well as α-Hb release from the α-Hb:AHSP complex were measured by time-resolved absorption spectroscopy.

Results

AHSP binding to α-Hb is kinetically controlled to prevail over direct binding with β-chains and is also thermodynamically controlled by the α-Hb redox state and not the liganded state of the ferrous α-Hb. The dramatic instability of isolated ferric α-Hb is greatly decreased upon AHSP binding. Removing the bis-histidyl hexacoordination in α-HbH58(E7)Q:AHSP complex reduces the stabilizing effect of AHSP binding. Once the ferric α-Hb is bound to AHSP, the globin can be more easily reduced by several chemical and enzymatic systems compared to α-Hb within the Hb-tetramer.

Conclusion

α-Hb reduction could trigger its release from AHSP toward its final Hb β-chain partner producing functional ferrous Hb-tetramers. This work indicates a preferred kinetic pathway for Hb-synthesis.

General significance

The cellular redox balance in Hb-synthesis should be considered as important as the relative proportional synthesis of both Hb-subunits and their heme cofactor. The in vivo role of AHSP is discussed in the context of the molecular disorders observed in thalassemia.  相似文献   
8.
Summary We demonstrate that the scores and frequencies of chlortoluron (CT) and metoxuron (MX) resistance and susceptible phenotypes of wild emmer wheat, Triticum dicoccoides, are correlated with ecological factors and allozyme markers. Some isozyme markers located on chromosome 6B (e.g. Adh,Est-4 and Got), which also harbours the CT and MX resistance gene, provide good genetic markers for herbicide resistance breeding. Significant correlations between herbicide and photosynthetic characters suggest that the evolution of herbicide resistance polymorphisms may be related to the process of photosynthesis in nature and predated domestication of cultivated wheat.  相似文献   
9.
随着转基因植物的大面积种植,转基因植物的生态风险受到广泛关注,其中主要的风险是转基因植物与近缘物种之间的基因流及其影响。本文综述了目前商业化种植的转基因作物油菜、棉花、玉米和大豆,以及未商业化种植的水稻、小麦的基因流研究进展;分析了不同转基因作物与其近缘种之间发生基因流的频率和最远发生距离;介绍了降低基因流发生的方法。基因流频率受物种亲缘关系、花期重叠时间、风速风向等因素的影响,最远发生距离受气候条件、传粉媒介、地理条件等因素的影响。转基因作物与其近缘种之间的基因流频率与距花粉源的距离呈负相关关系(y=-0.59x-0.46,R2=0.25,P<0.01),亲缘关系近的基因流频率高。为了降低转基因植物与其近缘物种之间的基因流风险,建议采取“分区管理”的策略,并加强基因流发生之后的生态风险评价研究。  相似文献   
10.
We describe the isolation, development and application of seven microsatellite loci in the eastern wild turkey, Meleagris gallopavo silvestris, as well as their amplification and levels of polymorphism in the domestic turkey. The number of alleles per locus ranged from 5 to 15 and average heterozygosity was high for almost all loci. Domestic turkeys showed significantly reduced numbers of alleles per locus and overall heterozygosities when compared to eastern wild turkeys. The high variability in these markers should provide the level of resolution required to continue studies of wild turkey population genetics.  相似文献   
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