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1.
To expand the availability of genes encoding enzymes and structural proteins associated with storage lipid synthesis and deposition, partial nucleotide sequences, or expressed sequence tags (ESTs), were obtained for 743 cDNA clones derived from developing seeds of castor (Ricinus communis L.). Enrichment for seed-specific cDNA clones was obtained by selecting clones that did not detectably hybridize to first-strand cDNA from leaf mRNA. Similarly, clones that hybridized to storage proteins or other highly abundant mRNA species from developing seeds were selected against. To enrich for endomembrane-associated proteins, some clones were selected for sequencing by immunological screening with antibodies prepared against partially purified endoplasmic reticulum membranes. Comparison of the deduced amino acid sequences of the ESTs with the public data bases resulted in the assignment of putative identities of 49% of the clones selected by differential hybridization and 71% of the clones selected by immunological screening. Open reading frames in 100 of the ESTs exhibited higher homology to 78 different nonplant gene products than to any previously known plant gene product. 相似文献
2.
基于表达序列标签的微卫星标记(EST-SSRs)研究进展 总被引:55,自引:0,他引:55
作为一种新型分子标记,EST-SSR来自表达基因,因而除具备传统基因组来源的SSR标记所有优势外,可能与基因功能表达具有直接或间接关系,从而强化了SSR标记在遗传研究中的应用.本文综述了近几年来EST-SSR用于遗传图谱构建、基因定位、比较基因组学及重要基因筛选和发掘等方面的研究. 相似文献
3.
分析鲫鱼EST资源的SSR信息,为开发EST-SSR标记奠定基础.从GenBank中获得鲫鱼EST序列,然后用Sequencher 4.8软件进行序列拼接得到Uni-EST序列,再通过SciRoKo 3.4软件扫描Uni-EST序列中的SSR,最后得出EST-SSR的分布特征、频率和重复基元类型等特征.通过搜索共获得9 230条鲫鱼EST原始序列,通过使用计算机软件进行预处理共得到全长为3.81×106 bp的无冗余Uni-EST 7 092条.在这些序列中共搜索出597个SSR位点,分布在545条Uni-EST序列中,发生频率为8.13%,EST-SSR的平均长度为(19.34±6.23) bp,平均每Mb含156.55个SSR位点.单核苷酸重复在鲫鱼EST-SSR中占主导地位,发生频率为39.53%,其次为二核苷酸重复,发生频率为36.68%以及三核苷酸重复的15.41%.在所有非单核苷酸重复基元中,AC基元出现频率最高,其次为AG.设计出引物404对.最后得出结论鲫鱼EST中SSR出现的频率较高,并且类型较为丰富,为进行遗传多样性分析和重要经济性状筛选等方面的研究提供了基础和指导. 相似文献
4.
Wei Tang Zhongchen Guo Fan Ouyang 《In vitro cellular & developmental biology. Plant》2001,37(5):558-563
Summary Mature zygotic embryos of eight (open-pollinated) families of loblolly pine (Pinus taeda L.) were cultured on eight different basal salt formulations, each supplemented with 36.2 μM 2,4-dichlorophenoxyacetic acid, 17.8 μM 6-benzyladenine, 18.6 μM kinetin, 500 mg l−1 casein hydrolysate, and 500 mg l−1
l-glutamine for 9 wk; embryogenic tissue was formed on cotyledons, hypocotyls, and radieles of mature zygotic embryos. Callus
was subcultured on the callus proliferation medium, the same as the induction medium but with one-fifth concentration of auxin
and cytokinin for 9 wk. On this medium a white to translucent, glossy, mucilaginous embryogenic callus containing embryogenic
suspensor masses (ESMs) was obtained. The highest frequency of explants forming embryogenic tissue, 17%, occurred on a modified
Murashige and Skoog salts basal medium containing the concentration of KNO3, Ca(NO3)2·4H2O, NH4NO3, KCl, ZnSO4·7H2O, and MnSO4·H2O, 720, 1900, 400, 250, 25.8, and 25.35 mg l−1, respectively. Embryogenic suspension cultures were established by culturing embryogenic callus in liquid callus proliferation
medium. Liquid cultures containing ESMs were transferred to medium containing abscisic acid, polyethylene glycols, and activated
charcoal for stimulating the production of cotyledonary somatic embryos. Mature somatic embryos germinated for 4–12 wk on
medium containing indole-butyric acid, gibberellic acid, 6-benzyladenine, activated charcoal, and reduced sucrose concentration
(15 g l−1). Two hundred and ninety-one regenerated plantlets were transferred to a perlite:peatmoss:vermiculite (1∶1∶1) mixture, then
the plants were transplanted to soil in the earth, and 73 plantlets survived in the field. 相似文献
5.
Wei Tang 《In vitro cellular & developmental biology. Plant》2000,36(6):488-491
Summary Desiccation tolerance can be induced by culturing somatic embryos of loblolly pine (Pinus taeda L.) on medium supplemented with 50 μM abscisic acid (ABA) and/or 8.5% polyethylene glycol (PEG6000). Scanning electron microscopy of desiccated somatic embryos showed that the size and external morphology of the desiccation-tolerant
somatic embryos recovered to the pre-desiccation state within 24–36 h, whereas the non-desiccation-tolerant somatic embryos
did not recover and remained shriveled, after rehydration. Peroxidase activity of desiccated somatic embryos increased sharply
after 1 d of desiccation treatment at 87% relative humidity (RH), and desiccation-tolerant somatic embryos had higher peroxidase
activity compared to sensitive somatic embryos. Higher peroxidase activity of desiccation-tolerant somatic embryos may have
allowed them to catalyze the reduction of H2O2 produced by drought stress, and protected them from oxidative damage. 相似文献
7.
With the ever increasing number of Expressed Sequence Tags (ESTs) from various sequencing projects, ESTs have become valuable and first-hand source of in-silico mining of simple sequence repeats (SSR) markers. We examined a total of 3419 EST sequences from three bamboo species, namely, Phyllostachys edulis, Bambusa oldhamii and Dendrocalamus sinicus for the presence of di- to hexa- microsatellites. The frequency of SSR containing ESTs varied from 5.36% in B. oldhamii to 13.05% in P. edulis. No SSRs were found in D. sinicus. Tri-nucleotide repeats (49.34%) were most frequent in P. edulis, while not much comparable difference in repeats was found in B. oldhamii. Flanking primer pairs were also designed in-silico for the sequences containing SSRs and their position on the genome hypothesized using similarity searching. SSRs located in open reading frame (ORF) were given functional annotation using Gene Ontology. Polymorphic SSRs were also detected using new pipeline- polySSR. Polymorphism level was very low (2.43%) and the position of the polymorphic SSRs was determined. The development of SSRs and the study of polymorphism will help in the further study of intra- and inter- gene flow, genetic structure, variability, linkage mapping and evolutionary relationships in bamboo. 相似文献
8.
Sigrid A. Lehnert Kate J. Wilson Keren Byrne Stephen S. Moore 《Marine biotechnology (New York, N.Y.)》1999,1(5):465-476
Expressed sequence tag data were generated from complementary DNA libraries created from cephalothorax, eyestalk, and pleopod
tissue of the black tiger shrimp (Penaeus monodon). Significant database matches were found for 48 of 83 nuclear genes sequenced from the cephalothorax library, 22 of 55 nuclear
genes from the eyestalk library, and 6 of 13 nuclear genes from the pleopod library. The putative identities of these genes
reflected the expected tissue specificity. For example, genes for digestive enzymes were identified from the cephalothorax
library and genes involved in the visual and neuroendocrine system from the eyestalk library. A few sequences matched anonymous
EST or genomic sequences, and others contained mini-satellite or microsatellite repeat sequences. The remainder, 31 from the
cephalothorax library, 25 from the eyestalk library, and 5 from the pleopod library, were sequences of high nucleotide complexity
with no matches in any database searched and thus may represent novel genes.
Received February 12, 1999; accepted April 13, 1999 相似文献
9.
Expressed Sequence Tags from a Root-Hair-Enriched Medicago
truncatula cDNA Library 总被引:3,自引:0,他引:3 下载免费PDF全文
The root hair is a specialized cell type involved in water and nutrient uptake in plants. In legumes the root hair is also the primary site of recognition and infection by symbiotic nitrogen-fixing Rhizobium bacteria. We have studied the root hairs of Medicago truncatula, which is emerging as an increasingly important model legume for studies of symbiotic nodulation. However, only 27 genes from M. truncatula were represented in GenBank/EMBL as of October, 1997. We report here the construction of a root-hair-enriched cDNA library and single-pass sequencing of randomly selected clones. Expressed sequence tags (899 total, 603 of which have homology to known genes) were generated and made available on the Internet. We believe that the database and the associated DNA materials will provide a useful resource to the community of scientists studying the biology of roots, root tips, root hairs, and nodulation. 相似文献
10.
11.
Plant regeneration through organogenesis from callus induced from mature zygotic embryos of loblolly pine 总被引:8,自引:1,他引:7
Mature zygotic embryos from three seed sources of loblolly pine were cultured on callus induction medium containing 10 mg
l–1
α-naphthaleneacetic acid, 4 mg l–1 benzyladenine (BA), 400 mg l–1 casein hydrolysate, and 400 mg l–1 glutamine for 6 weeks. Light-yellow, loose, glossy, globular callus was formed, and the highest frequency was 35.7%. The
highest differentiation frequency of callus on adventitious bud induction medium was 62.1%. After culture of calli with adventitious
buds on elongation medium for 6 weeks, adventitious shoots more than 1.0 cm in height were selected for rooting. On rooting
medium supplemented with 0.1 mg l–1 indole-3-butyric acid, 1 mg l–1 BA, and 0.5 mg l–1 gibberellic acid, the highest rooting frequency of adventitious shoots was 46% in a culture period of 6 weeks. Established
plants survived following transfer to soil at a frequency of 71%.
Received: 14 May 1997 / Revision received: 25 September 1997 / Accepted: 11 October 1997 相似文献
12.
Two non-normalized cDNA libraries of uteri from Danish Landrace and Chinese Erhualian pigs were constructed, and 13,756 expressed sequence tags (ESTs) were randomly sequenced. The ESTs were clustered by Phrap software, and 6,139 distinct tentative consensus sequences were produced, including 2,730 contigs and 3,409 singlets. Using Blast tools, these 6,139 candidate genes were compared to the nr and nt databases; 5,210 of them were assigned putative functions, whereas 929 potentially represent new genes. Highly expressed genes appear to be associated with basic energy metabolism, transferase activity, localization, cellular physiological process, protein binding, and nucleic acid binding. Antileukoproteinase was the most highly expressed gene, corresponding to endometrial differentiation and conceptus or fetal development. 相似文献
13.
The bay scallop, Argopecten irradians irradians, introduced from North America, has become one of the most important aquaculture species in China. Inan effort to identify
scallop genes involved in host defense, a high-quality cDNA library was constructed from whole body tissues of the bay scallop.
A total of 5828 successful sequencing reactions yielded 4995 expressed sequence tags (ESTs) longer than 100 bp. Cluster and
assembly analyses of the ESTs identified 637 contigs (consisting of 2853 sequences) and 2142 singletons, totaling 2779 unique
sequences. Basic Local Alignment Search Tool (BLAST) analysis showed that the majority (73%) of the unique sequences had no
significant homology (E-value ≤ 0.005) to sequences in GenBank. Among the 748 sequences with significant GenBank matches,
160 (21.4%) were for genes related to metabolism, 131 (17.5%) for cell/organism defense, 124 (16.6%) for gene/protein expression,
83 (11.1%) for cell structure/motility, 70 (9.4%) for cell signaling/communication, 17 (2.3%) for cell division, and 163 (21.8%)
matched to genes of unknown functions. The list of host-defense genes included many genes with known and important roles in
innate defense such as lectins, defensins, proteases, protease inhibitors, heat shock proteins, antioxidants, and Toll-like
receptors. The study provides a significant number of ESTs for gene discovery and candidate genes for studying host defense
in scallops and other molluscs. 相似文献
14.
15.
16.
Summary Several factors that may affect induction of somatic embryogenesis in loblolly pine (Pinus taeda L.) were investigated in 1994 and 1995. Megagametophytes containing immature zygotic embryos were excised from seeds as explants.
Potassium chloride, silver nitrate, myo-inositol, coconut water, or polyamine was added to the control media (U.S. patent
no. 5,036,007) to determine the effects of each single ingredient or their combinations on the initiation of embryogenic tissue.
Supplements of myo-inositol at 22.2 mM resulted in increases in frequencies of cell mass extrusion and proliferation compared with the control media in consecutive
years. Addition of silver nitrate showed the potential to promote initiation of embryogenic culture. The combination of 10
mM potassium with 29.4 μM silver nitrate achieved the highest frequencies in both extrusion and proliferation of embryogenic tissue. The combination
of silver nitrate at 29.4 μM with addition of myo-inositol at 11.1 or 22.2 mM achieved a higher conversion rate from extrusion to proliferation. Polyamine did not significantly affect the induction of
somatic embryogenesis, but coconut water was inhibitory.
Published with approval of the Director of Arkansas Agricultural Experimental Station. 相似文献
17.
18.
目的:利用基因芯片数据,探讨宫颈癌在分子水平上的发病机制,挖掘肿瘤相关基因EST片段,探索恶性肿瘤标志物,为肿瘤防治找到新的有效手段。方法:从基因芯片数据库GEO(gene expression omnibus)中获得GSM99077基因芯片数据,利用该数据筛选出宫颈癌相关基因的EST片段;然后通过NCBI中的在线BLAST软件找到与之相匹配的同源序列,对这些同源序列进行生物学功能分析,找到与肿瘤的相关性。结果:共发现宫颈癌组织与正常宫颈组织差异表达EST共127条,其中上调的106条,下调的11条,这些差异表达EST的同源序列的转录产物参与转录、翻译、细胞增殖分裂及细胞信号传导等过程。结论:基因芯片能有效、高通量地获取生物内在信息,通过对基因芯片数据再挖掘,可发现宫颈癌的发生涉及多个基因共同作用。 相似文献
19.
Woo-Jin Kim Hyungtaek Jung Patrick M. Gaffney 《Marine biotechnology (New York, N.Y.)》2011,13(2):127-132
Expressed sequence tag (EST) databases provide a primary source of nuclear DNA sequences for genetic marker development in
non-model organisms. To date, the process has been relatively inefficient for several reasons: 1) priming site polymorphism
in the template leads to inferior or erratic amplification; 2) introns in the target amplicon are too large and/or numerous
to allow effective amplification under standard screening conditions; and 3) at least occasionally, a PCR primer straddles
an exon–intron junction and is unable to bind to genomic DNA template. The first is only a minor issue for species or strains
with low heterozygosity but becomes a significant problem for species with high genomic variation, such as marine organisms
with extremely large effective population sizes. Problems arising from unanticipated introns are unavoidable but are most
pronounced in intron-rich species, such as vertebrates and lophotrochozoans. We present an approach to marker development
in the Pacific oyster Crassostrea gigas, a highly polymorphic and intron-rich species, which minimizes these problems, and should be applicable to other non-model
species for which EST databases are available. Placement of PCR primers in the 3′ end of coding sequence and 3′ UTR improved
PCR success rate from 51% to 97%. Almost all (37 of 39) markers developed for the Pacific oyster were polymorphic in a small
test panel of wild and domesticated oysters. 相似文献
20.
Regeneration of transgenic loblolly pine (Pinus taeda L.) from zygotic embryos transformed with Agrobacterium tumefaciens 总被引:4,自引:0,他引:4
Embryos of 24 open-pollinated families of loblolly pine (Pinus teade L.) were used as explants to conduct in vitro regeneration. Then, Agrobacterium tumefaciens strain GV3101 harboring the plasmid pPCV6NFHygGUSINT was used to transform mature zygotic embryos of seven families of loblolly pine. The frequency of transformation varied among families infected with A. tumefaciens. The highest frequency (100%) of transient beta-glucuronidase (GUS)-expressing embryos was obtained from family 11-1029 with over 300 blue spots per embryo. Expression of the GUS reporter gene was observed in cotyledons, hypocotyls, and radicles of co-cultivated mature zygotic embryos, as well as in callus and shoots derived from co-cultivated mature zygotic embryos. Ninety transgenic plants were regenerated from hygromycin-resistant callus derived from families W03. 8-1082 and 11-1029. and 19 transgenic plantlets were established in soil. The presence of the GUS gene in the plant genome was confirmed by polymerase chain reaction. Southern blot, and plant DNA/T-DNA junction analysis. These results suggest that an efficient A. tumefaciens-mediated transformation protocol for stable integration of foreign genes into loblolly pine has been developed and that this transformation system could be useful for future studies on transferring economically important genes to loblolly pine. 相似文献