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991.
本文记述狭顶叶蝉属Angustella2新种,即:白斑狭顶叶蝉A.albonotata.sp.nov,黑背狭顶叶蝉A.nigrinotasp.nov,模式标本保存在中国科学院动物研究所。  相似文献   
992.
Two new triterpenoids, octanordammar-1,11,13(17)-trien-17-ol-3,16-dione (1) and lup-12-en-15α,19β-diol-3,11-dioxo-28-oic acid (4), as well as 13 known compounds were isolated from the roots of Sanguisorba officinalis L. (Rosaceae). Their structures were determined using spectroscopic methods.  相似文献   
993.
994.
Rhodococcus erythropolis PR4 is a marine bacterium that can degrade various alkanes including pristane, a C(19) branched alkane. This strain produces a large quantity of extracellular polysaccharides, which are assumed to play an important role in the hydrocarbon tolerance of this bacterium. The strain produced two acidic extracellular polysaccharides, FR1 and FR2, and the latter showed emulsifying activity toward clove oil, whereas the former did not. FR2 was composed of D-galactose, D-glucose, D-mannose, D-glucuronic acid, and pyruvic acid at a molar ratio of 1:1:1:1:1, and contained 2.9% (w/w) stearic acid and 4.3% (w/w) palmitic acid attached via ester bonds. Therefore, we designated FR2 as a PR4 fatty acid-containing extracellular polysaccharide or FACEPS. The chemical structure of the PR4 FACEPS polysaccharide chain was determined by 1D (1)H and (13)C NMR spectroscopies as well as by 2D DQF-COSY, TOCSY, HMQC, HMBC, and NOESY experiments. The sugar chain of PR4 FACEPS was shown to consist of tetrasaccharide repeating units having the following structure: [structure: see text].  相似文献   
995.
小麦籽粒不同部位的矿质元素组成与其含量差异   总被引:4,自引:0,他引:4  
采用X-射线能谱仪测定非糯与糯性等品种小麦籽粒不同部位的矿质元素组成(H和He元素除外)和含量的结果表明:小麦籽粒中除含有大量C、O外,皮层富含K、P、se,其次是Cl、Si、S、Mg和Ca等;糊粉层富含P、K和Mg,其次是Si、Se、S、Ca、Cl和Fe等;胚乳层中相应的矿质元素含量比皮层和糊粉层低。不同品种籽粒各部位的矿质元素含量存在遗传性差异。据此认为籽粒磨成粉时应减少糊粉层的损失,以提高面粉的矿质价值。  相似文献   
996.
Bisexual fertile diploid androgenetic individuals (A0) (2n=100) were formed by androgenesis. In this way, the diploid spermatozoa from male allotetraploid hybrids (AT) (4n=200) of red crucian carp (Carassius auratus red var.) (♀) × common carp (Cyprinus carpio L.) (♂) were used to fertilize the UV-treated hap- loid eggs of goldfish (Carassius auratus), and living androgenetic diploid fish were developed. The A0 became sexually mature at the age of 2 years, and they fertilized with each other to form their offspring (A1). In this study, we observed the chromosomal number, gonadal structure and appearance of A1 fish. The results are as follows: (1) In A1, there were 85% tetraploids (A1-4n), 10% triploids (A1-3n) and 5% diploids (A1-2n), suggesting that diploid A0 could produce diploid gametes. It was concluded that the formation of diploid gametes generated from diploid A0 was probably related to the mechanism of pre-meiotic endoreduplication. (2) Among A1, only A1-4n possessed normal ovaries and testes. The mature males of A1-4n produced white semen. Under the electron microscope, the head of diploid sperm generated by A1-4n was bigger than that of haploid sperm generated by red crucian carp. In the testes of the A1-4n, there were many mature normal spermatozoa with a head bearing plasma mem- brane and a tail having the typical structure of "9 2" microtubules. Between the head and the tail, there were some mitochondria. The ovaries of A1-4n developed well and mainly contained II, III and IV-stage oocytes. The IV-stage oocytes were surrounded by inner and outer follicular cells. The micropyle was observed on the oolemma of follicular cells. There were abundant yolks and plenty of endoplasmic reticulum in the cytoplasm of IV-stage oocytes. Because A1-2n and A1-3n were distant crossing diploid hybrids and triploid hybrids respectively, they possessed abnormal gonads, and no mature semen and eggs were observed. (3) Compared with allotetraploids, the A1-4n fish not only had advantages such as fast growth rate and strong resistibility but also showed some new good performances such as high ratio of body width to body length, smaller heads and shorter tails. These results indicated that an- drogenesis could produce bisexual fertile tetraploids and improve the shape of allotetraploid hybrids as well, which will be of great significance in both the cell genetics research and fish breeding.  相似文献   
997.
In this study, we have investigated the plant growth promoting effect of Bacillus mucilaginosus strain D4B1, a rhizosphere soil organism, and its transgenic strain NKTS-3 on tobacco planting. The transgenic strain contains a phytase expression cassette that can express high active phytase extracellularly and hydrolyze phytate in the soil to liberate inorganic phosphorus for the growth of tobacco plants. Greenhouse study and field experiments showed that both wild-type B. mucilaginosus and the transgenic strain could promote tobacco plant growth. Moreover, the transgenic strain promoted tobacco plant growth (235% more than control in pot experiments and 125% more than control in field experiments) was higher than the wild-type B. mucilaginosus (183% more than control in pot experiments and 108% more than control in field experiments). In addition, the inoculation with transgenic rhizobacteria could significantly improve root acquisition of phosphorus and increase the phosphorus content of the plant.  相似文献   
998.
Despite increasing use of cell-based assays in high-throughput screening (HTS) and lead optimization, one challenge is the adequate supply of high-quality cells expressing the target of interest. To this end, cell lines stably expressing targets are often established, maintained, and scaled up by cell culture. These steps require large investments of time and resources. Moreover, significant variability invariably occurs in cell yield, viability, expression levels, and target activities. In particular, stable expression of targets such as transient receptor potential A1 (TRPA1) causes toxicity, cell line degeneration, and loss of functional activity. Therefore, in an effort to identify TRPA1 antagonists, the authors used large-scale transiently transfected (LSTT) cells, enabling rapid establishment of assays suitable for HTS. LSTT cells, which could- be stored frozen for a long period of time (e.g., at least 42 weeks), retained TRPA1 protein expression and could be easily revived to produce robust and consistent signals in calcium influx and electrophysiological assays. Using cells from a single transfection, a chemical library of 700,000 compounds was screened, and TRPA1 antagonists were identified. The use of LSTT circumvented issues associated with stable TRPA1 expression, increased flexibility and consistency, and greatly reduced labor and cost. This approach will also be applicable to other pharmaceutical targets.  相似文献   
999.
凤蝶亚科(凤蝶科,鳞翅目)16S rRNA基因的分子系统发生分析   总被引:2,自引:0,他引:2  
对15种凤蝶亚科蝶类线粒体16S rRNA基因部分序列进行了测定,并结合GenBank中其它相关类群的序列,采用邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和贝叶斯法构建凤蝶亚科的分子系统树,探讨该亚科各类群间的系统发生关系.结果表明,燕凤蝶族构成凤蝶亚科蝶类系统树基部的一个独立分支;燕凤蝶族和裳凤蝶族为单系发生,且裳凤蝶族聚在凤蝶族内部;喙凤蝶族的单系性尚不能确定.综合分子系统学、形态学及寄主植物等相关证据,推测斑凤蝶类为凤蝶族中早期分化的一支;较之裳凤蝶类,斑凤蝶类可能更早从二者最近的共同祖先中分化出来.  相似文献   
1000.
袁晓萌  周云涛  张红岩  薛华  周琳  赵云 《遗传》2007,29(12):1525-1528
通过筛选野生型油菜(Pet33-10)与无花瓣油菜(Apet33-10)反向消减文库(SSH)和运用RACE-PCR技术, 获得了甘蓝型油菜小核糖核蛋白BnSmD1的全长编码区 cDNA (GenBank登陆号DQ298446)。该基因长484 bp, 含有一个长354 bp的阅读框。BnSmD1在N端拥有两个高度保守的结构域(Sm-1和Sm-2), 羧基端则含有一个RG重复序列。Northern blot表达结果显示: BnSmD1在甘蓝型油菜的各个组织均有表达, 但是它在早期花蕾中的表达明显高于同期的叶和茎。通过对BnSmD1在Apet33-10无花瓣品系与野生型有花瓣品系Pet33-10中各组织的表达差异进行比较, 发现该基因在Apet33-10的早期花蕾中表达明显下降。因此, BnSmD1可能对植物的早期花发育起到了重要的作用, 并很有可能影响花瓣的形成。  相似文献   
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