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1.
综述了国内外对刺五加体细胞胚发生研究的现状。分别对刺五加体细胞胚发生方式、体细胞胚发育相关生理生化变化(包括生长素极性运输、DNA甲基化和代谢途径调控)、体细胞胚生物反应器培养的研究现状进行了评述。  相似文献   

2.
潘巧仪  阎书凤 《蛇志》1999,11(1):79-80
药物流行病学是临床药理学和流行病学结合而产生的一门新兴的边缘科学,是研究药物在人群中的应用及效应的学科。近10余年来迅速发展,并有研究分支:如药物经济学、药效学、药物利用研究等。本文对该学科定义、范畴及其发生、发展和现状作一简要概述。1定义及范畴药物...  相似文献   

3.
作者对贻贝科贝类的幼虫和幼贝期发育阶段形态结构的出现和变化顺序进行了研究,其约60个不同分类单元的个体发生可归纳为4种形态发生类型或模式。主要对3个形态发生区域的阶段形态结构的起源、发育变化和同源性做了研究。其一,即中央区域,开始形成于前双壳Ⅰ期(PD-Ⅰ),在某个分类单元它可以在前双壳Ⅱ期(PD-Ⅱ)和幼贝期(N)形成,而在其它分类单元则在前双壳Ⅱ期、幼贝期和双壳期(D)形成;第二区域,即背部后区,在幼贝期出现;第三区域,即背部前区,出现于双壳期。双壳期背部后区在某个分类单元起源于幼贝期的形态构造,在其它分类单元则可能起源于双壳期的形态构造。与在贻贝分类学上应用的成体特征相比,早期发育阶段中央和背部后区的形态结构显示出很明显的发育顺序或特征变化规律。根据以前人们熟知而尚未应用到分类和系统发育研究中的早期发育阶段形态特征,作者重新修订了Soot-Ryen的现生贻贝科种上阶元分类系统,重新提出了科内系统发育关系。修订的分类系统表明,Scarlato and Starobogatov(1984)提出的贻贝科各亚科由偏顶蛤亚科开始,沿4条系统发育路线演化发展,对应其早期发育阶段的4类形态发生类型或模式。  相似文献   

4.
淡水龟科具闭壳结构龟类分类及系统进化研究进展   总被引:1,自引:0,他引:1  
闭壳龟类是淡水龟科(Bataguridae)中一群具有"闭壳"结构的水栖或半水栖龟类的总称,即腹甲的腹盾和胸盾之间以可动的铰链韧带相连,使背甲和腹甲可以全部或部分闭合,它们是盒龟属(Cistoclemmys)、闭壳龟属(Cuo-ra)、锯缘龟属(Pyxidea)、齿缘龟属(Cyclemys)和果龟属(Notochelys),前4个属的龟类在中国均有分布。近几十年来,由于食用、传统中医药开发和宠物贸易的兴起,导致许多闭壳龟类野生物种数量急剧减少,并且当前许多亚洲闭壳龟的分类工作过多的依赖于市场购买的物种样本,这就使我们对闭壳龟属及种的归属划分变的较困难,因此对闭壳龟类物种种的界限的划分及属间系统发育关系的研究仍然是一个艰巨的挑战。通过对淡水龟科具有闭壳结构龟类的形态学研究,细胞遗传学研究以及分子系统学研究等进行了综述,以期为闭壳龟类的相关保护研究提供参考。  相似文献   

5.
冬虫夏草是一种名贵的药用真菌,由于其多功能的药用价值而成为各国研究的热点。本文对冬虫夏草遗传多样性、冬虫夏草系统发生、冬虫夏草的酶和文库的研究做了综述,并对冬虫夏草的研究做了展望。  相似文献   

6.
激素对百合植株再生的影响   总被引:11,自引:0,他引:11  
刘明志  林雪艳 《广西植物》2002,22(2):167-170
本研究设计了 1 5种不同配比的激素组合研究 2 ,4 -D和 6 -BA对百合鳞片叶器官发生和体细胞胚胎发生的影响。结果表明 :在 MS培养基上 ,BA可诱导外植体直接分化不定芽 ,其中 1 .0~ 2 .0 mg/L BA诱导不定芽的分化频率最高 ,6 .0 mg/L BA抑制不定芽分化 ;2 ,4 -D可诱导直接体细胞胚胎发生 ,其中 4 .0 mg/L2 ,4 -D诱导体细胞胚胎发生的频率最高 ,而 6 .0 mg/L 2 ,4 -D诱导体细胞胚胎发生的频率降低 ;当培养基中同时含有 BA和 2 ,4 -D时 ,既出现不定芽 ,又出现体细胞胚。当再生苗移入无激素的 MS培养基和含有 1 .0mg/L和 2 .0 mg/L IAA的 MS培养基上时 ,只有无激素的 MS培养基有利于根的形成。此外 ,鳞片叶的大小和外植体的接种方向也影响外植体分化  相似文献   

7.
鱼类血细胞的研究进展   总被引:14,自引:2,他引:12  
综述了鱼类血细胞分类、发生及功能研究领域的概况和进展,以期为有关研究提供参考。  相似文献   

8.
鸡形目鸟类系统发生研究现状   总被引:2,自引:2,他引:0  
综合形态学、行为学、分子系统发生等方面研究成果,对世界鸡形目鸟类科的系统关系以及属、种间系统发生的研究进展进行了阐述,侧重介绍与我国鸡形目鸟类相关类群的系统发生研究现状。与传统的系统关系比较,新的研究结果主要有:凤冠雉科和冢雉科不再是互为姊妹群;传统分类中的雉族和鹑族被证明并非单源而是多源的;雉族的原鸡属与鹑族的竹鸡属有很近的亲缘关系;灰山鹑、火鸡和松鸡类的系统发生关系可能很近。分子进化的研究表明雉科各属的起源主要集中在上新世。  相似文献   

9.
柑桔红蜘蛛(PanonychuscitriMcGregor)又称桔全爪螨,属蛛形纲,蜱螨亚目,叶螨科。自80年代以来,由于生态失衡,抗药性等原因,红蜘蛛成为柑桔主要害虫之一。其成螨、若螨和幼螨均为害柑桔的叶片、绿色枝梢及果实,尤以叶片受害最重,被害叶片失去光泽,严重时大量落叶,影响树势和产量。为了经济、安全、有效地控制红蜘蛛的猖獗为害,从1988年以来,我站承担“柑桔病虫综合防治”项目,对红蜘蛛发生规律及综合防治进行了调查研究,并总结出相应的综合防治措施。1发生规律柑桔红蜘蛛在我县年发生20余代,周年可见,世代重叠,冬季无滞育现象。行两性生殖,…  相似文献   

10.
分子生物学技术,如等位酶分析、DNA序列分析、限制性片段长度多态性、随机扩增多态、重复DNA序列多态性,在轮虫研究中的应用始于上世纪70年代,研究领域主要是轮虫群体遗传学、生物变异与多样性和系统发生与进化,被研究的轮虫种类主要集中在臂尾轮虫属、晶囊轮虫属和蛭态轮虫的一些种类。着重介绍分子生物学技术在轮虫遗传学和系统学研究中的应用,并对今后的研究热点提出了展望。  相似文献   

11.
在果实成熟的1~3月,采样分析盖膜和不盖膜沙糖橘果实品质。结果表明:树冠盖膜后沙糖橘果皮色泽一直保持橘红色,而不盖膜的果皮色泽由前期的橘红色转为后期的橘黄色,且色泽暗淡;盖膜处理果实的酸含量在开始的20d内呈上升趋势,1月28日出现最高值0.31%,此后的10d内迅速下降至低于对照的水平,2月7日出现最低值,此后的20d内上升高于对照,之后又下降至3月15日的0.19%;对照果实的酸含量呈现明显的下降趋势,1月7日出现最高值为0.26%,3月15日出现最低值为0.08%,盖膜处理果实的酸含量在大多数时间内高于对照;盖膜处理果实的可溶性固形物含量从1月17日的12.33%提高到3月15日的13.40%,提高了1.07个百分点,总体呈上升趋势,而对照的从1月17日的10.70%下降至3月15日的9.90%,下降了0.80个百分点,总体呈下降趋势。  相似文献   

12.
Changes of fat distribution were followed up in Czech and Slovak children from 1.5 to 15 years of age, using centrality indices, which relate the values of skinfolds on the trunk to the skinfolds on the extremities, head and neck. Up to 5 years of age, subcutaneous fat was deposited relatively more on the extremities, head and neck than on the trunk, which was expressed by lower values of the centrality indices. After the age of 5 years, the accumulation of subcutaneous fat was greater on the trunk, which was also expressed by higher values of the centrality indices. The comparison of the individual indices revealed in both genders a relatively higher amount of subcutaneous fat on the trunk in boys until 12 years of age. During puberty subcutaneous fat over triceps and on the forearm was reduced. In girls the deposition of the subcutaneous fat was relatively greater at different sites of the trunk than in boys, with the exception of the age of 14-15 years. The deposition of subcutaneous fat was greater on the trunk than on the head (cheek) and on the extremities in Czech compared to Slovak children, except for 12-year-old girls. During the period between the fifties and the seventies of the last century, in Czech children, especially in girls, the deposition of subcutaneous fat on the trunk was relatively smaller than on other parts of the body surface, which was expressed by the reduction of the centrality indices. Index 12 was therefore considered as the most valuable for the characterization of fat distribution on the body surface.  相似文献   

13.
二化螟水稻种群与茭白种群光周期反应的比较   总被引:2,自引:0,他引:2  
本文报道了用水稻和茭白分别饲养二化螟水稻种群和茭白种群的光周期反应。光周期反应曲线显示,用水稻饲养茭白种群或用茭白饲养水稻种群,无论是在短光照还是在长光照条件下,绝大多数幼虫被诱导进入滞育,丧失了各自原有的光周期反应特性,表明这两个种群已分化到仅适应其本身寄主的程度。用水稻饲养的茭白种群仅有5%~6%的个体化蛹,且其幼虫期较用茭白饲养的延长了15~18天;而用茭白饲养的水稻种群有30%~40%的个体化蛹,其幼虫期与水稻饲养的仅相差3~8天。茭白种群用水稻饲养时32日龄幼虫体重仅为茭白饲养的53.1%,而水稻种群用水稻饲养时32日龄幼虫体重为茭白饲养的79.5%。这些结果表明,茭白种群不适应取食水稻,而水稻种群对取食茭白则有一定的适应能力。根据这些结果,我们认为:(1)这两个种群已出现种下分化的迹象;(2)茭白种植不会对水稻田二化螟的发生产生大的影响。  相似文献   

14.
A fast and convenient method for silver staining of proteins on electroblotting membranes was developed based on Gallyas' histochemical intensifier and applied to human endothelial cell proteins separated by one- and two-dimensional electrophoresis and electroblotted to polyvinyl difluoride membranes. The method allowed detection of proteins on membranes with a sensitivity equal to the sensitivity of the most sensitive silver-staining protocols for electrophoresis gels. Also, the method was compatible with preceding immunostaining on the same membrane. Furthermore, an intensifying method for proteins in silver-stained SDS-PAGE gels was developed based on Gallyas' histochemical intensifier. This method was applied to proteins separated by one- and two-dimensional gel electrophoresis and visualized by one of several silver-staining methods. Maximal intensification was achieved for the less sensitive but fast acidic silver-staining protocols, but even for the very sensitive alkaline protocols a significant increase in signal to noise ratio was obtained. In particular, negatively stained or invisible proteins on the silver-stained gels were found to be visualized by the Gallyas stain. Proteins from silver-stained and Gallyas-stained gels were identified by mass spectrometry, and the intensification procedure was fully compatible with mass spectrometry.  相似文献   

15.
Glucoamylase (GA) was immobilized by adsorption on carbon support: on Sibunit, on bulk catalytic filamentous carbon (bulk CFC) and on activated carbon (AC). This was used to prepare heterogeneous biocatalysts for the hydrolysis of starch dextrin. The effect of the texture characteristics and chemical properties of the support surface on the enhancement of the thermal stability of the immobilized enzyme was studied, and the rates of the biocatalyst's thermal inactivation at 65-80 degrees C were determined. The thermal stability of glucoamylase immobilized on different carbon supports was found to increase by 2-3 orders of magnitude in comparison with the soluble enzyme, and decrease in the following order: GA on Sibunit>GA on bulk CFC>GA on AC. The presence of the substrate (dextrin) was found to have a significant stabilizing effect. The thermal stability of the immobilized enzyme was found to increase linearly when the concentration of dextrin was increased from 10 wt/vol % to 50 wt/vol %. The total stabilization effect for glucoamylase immobilized on Sibunit in concentrated dextrin solutions was about 10(5) in comparison with the enzyme in a buffer solution. The developed biocatalyst, 'Glucoamylase on Sibunit' was found to have high operational stability during the continuous hydrolysis of 30-35 wt/vol % dextrin at 60 degrees C, its inactivation half-time (t1/2) exceeding 350 h. To improve the starch saccharification productivity, an immersed vortex reactor (IVR) was designed and tested in the heterogeneous process with the biocatalyst 'Glucoamylase on Sibunit'. The dextrin hydrolysis rate, as well as the process productivity in the vortex reactor, was found to increase by a factor of 1.2-1.5 in comparison with the packed-bed reactor.  相似文献   

16.
卷蛾分索赤眼蜂雌蜂的颜色偏好性   总被引:1,自引:0,他引:1  
为了确定卷蛾分索赤眼蜂Trichogrammatoidea bactrae Nagaraja 雌蜂的颜色偏好性, 在室内通过在培养皿底部黏贴彩纸的方法测定卷蛾分索赤眼蜂雌蜂对红、 黄、 黑、 紫、 绿、 白、 蓝7种颜色的行为趋性反应。结果表明, 卷蛾分索赤眼蜂雌蜂在红、 黄、 紫、 绿和蓝5种颜色上的滞留时间都极显著地高于对照(P<0.01), 在黑和白2种颜色上的滞留时间与对照没有显著差异(P>0.05); 对黄色的首次选择率极显著高于对照(P< 0.01), 对红、 紫、 绿和蓝色的首次选择率均显著高于对照(P<0.05), 对黑色和白色的首次选择率与对照没有显著差异。当雌蜂分别在黄与红、 紫、 绿和蓝两两颜色之间选择时, 雌蜂在黄色彩纸上的滞留时间显著长于其他4种颜色。当雌蜂对红、 紫、 绿、 蓝和黄色5种颜色一起选择时, 在首次选择率、 滞留次数上5种颜色间都没有明显差异(P>0.05); 但在红色和蓝色上的滞留时间显著长于紫色(P<0.05), 在这3种颜色上的滞留时间与在黄色和绿色上的滞留时间均无显著差异(P>0.05)。卷蛾分索赤眼蜂雌蜂在7种颜色卵卡上分别与透明纸(对照)上的米蛾卵的选择寄生时, 在黄色卵卡上的寄生卵量极显著多于对照(P<0.01), 黑色卵卡上的寄生卵量极显著少于对照(P<0.01), 其他5种颜色的卵卡上的寄生卵量与对照没有显著差异(P>0.05)。结果说明, 卷蛾分索赤眼蜂雌蜂对黄色最为偏好, 其次偏好红、 紫、 绿和蓝色, 较不喜好白色和黑色。  相似文献   

17.
Ovarian follicular development was studied in 13 heifers by daily ultrasound examination during 2 complete and consecutive natural oestrous cycles. In 21 cycles (81%) 3 dominant follicles were identified, in 4 cycles (15%) 2 and in the remaining cycle 1 (4%). Consistently, the first dominant follicle was detected on average on Day 4, reached a maximum size on Day 6, went through a period of relative stability between Days 6 and 10, then began to decrease in size and was undetectable by Day 15. The second dominant follicle was detected by Day 12, reached maximum size on Day 16 (or 19 in the 4 cycles in which the 2nd dominant follicle was the ovulatory follicle) and was undetectable by Day 19. The 3rd (ovulatory) follicle was identified on average by Day 16 (range Days 10 to 19) and maximum size was reached on Day 21. The ovulatory follicles were larger (P less than 0.05) than the previous ones and the stage of the cycle at which maximum size was reached was significantly different for each dominant follicle (P less than 0.05). The analysis of the rates of growth and atresia suggest that the rate of growth is slowest during mid-cycle. The number of dominant follicles that developed in the ovary ipsilateral to the corpus luteum was greater (P less than 0.05) than in the contralateral ovary.  相似文献   

18.
TRH (10 and 1000 micrograms/kg body weight (BW] was injected ip into pregnant rats daily from day 0 to 20 of pregnancy, and the pituitary-thyroid axis of their pups (Mat-TRH rats) was examined on days 0, 4, 10, 21 and 90 after birth. The pituitary TSH content of male Mat-TRH rats was significantly lower on day 4, and higher on day 10 than that of control rats. The serum TSH was significantly higher on day 10 (except female 10 micrograms/kg group). An exaggerated TSH response to exogenous TRH (10 micrograms/kg BW; ip) was observed on day 10 (males, 1000 micrograms/kg group). The serum T4 level of female Mat-TRH rats was low on day 4 (1000 micrograms/kg group), and higher on day 10. On days 21 and 90, the levels of pituitary TSH, serum TSH and T4 in Mat-TRH rats were similar to those in controls, but the TSH response to TRH was still exaggerated (1000 micrograms/kg group). No significant difference between control and TRH-treated mothers was seen on days 10 and 90 postpartum except for a decreased pituitary TSH content on day 10 in the 1000 micrograms/kg group. It is concluded that repeated administration of TRH to pregnant rats shows an effect on the pituitary-thyroid axis function of their progeny in later life.  相似文献   

19.
Studies on biogeography of stony corals from the eastern Pacific have been conducted in detail only for reef species, and to date there have been no attempts to explain the differences of regional species richness on the basis of oceanographic conditions. The objective of this work was to determine the relationship between deep-water (<200 m) scleractinian species richness along the western coast of the Americas, and four oceanographic variables (temperature, nitrates, phosphates and silicates), and the feasibility to use this information to model effects of global warming on those associations. Data on coral distribution were gathered from bibliography and museum collections, while information on oceanographic conditions from 200 to 2000 m depth was obtained from NOAA atlases. Species richness, estimated for intervals of 5 degrees of latitude, was correlated with abiotic factors using the Spearman rank coefficient. In the Northern Hemisphere, total species richness was positively influenced by temperature, but negatively by nutrients. In contrast, there was no effect of those factors on coral diversity in the Southern Hemisphere. At the family level, high temperatures favored species richness of Caryophylliidae and Dendrophylliidae north of the Equator, but diversity was reduced in areas of high concentration of silicates. In the Southern Hemisphere, temperature was not associated with deep-water coral richness, but correlated negatively with diversity of Caryophylliidae. Nutrients also showed an inverse relationship with richness of the latter family. In the rest of the families analyzed, there was no apparent effect of oceanic conditions on species richness in the Southern Hemisphere. The results indicated that richness may be influenced by changes in oceanographic factors (especially temperature and silicate concentration). Then, it is feasible to develop numerical models to predict possible changes in deep-water coral diversity on the basis of scenarios from global warming models.  相似文献   

20.
The effect of boric acid on somatic embryo induction in rice was investigated using mature seeds of a widely used cytoplasmic male sterile line of indica rice IR-58025. Boric acid was added at a concentration of 100.00, 161.29, 241.93, 322.58 and 403.22 μM to the embryo induction medium containing basal salts, with 9.84 μM 2,4-dichlorophenoxyacetic acid. Boric acid was found to exert different effects on scutellum, coleoptile and root tissues. Increased growth of embryogenic masses with increasing boric acid concentrations was observed on coleoptile tissues of mature seed. Embryogenic response was observed at 161.29 μM boric acid on coleoptile and 241.93 μM boric acid on root tissue. Scutellum tissue showed embryonic response in 161.29 and 241.93 μM boric acid. The results indicate that the boric acid used in standard Murashige and Skoog medium is not sufficient to support induction of somatic embryogenesis in IR-58025 A. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

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