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The "phospholipid effect" which is the enhanced turnover of the phosphorylinositol group of phosphatidylinositol (PI) occurs in the thyroid of response to thyreostimulin (TSH). The possibility that Ca2+ ions are involved in this stimulation has been investigated with pig thyroid slices. Experiments performed in media without Ca2+ or containing E.G.T.A. (2 mM), indicate that it is not the extracellular Ca2+ which is implied, but rather the intracellular Ca2+. The ionophore A23187 (6.10(-6) M) increases the specific radioactivity of the acid soluble precursors, but has also a specific effect on the PI turnover, which is additive with the effect of a high concentration of TSH (50 mU/ml). Washing and loading of slices with various Ca2+ concentrations show that 0.9 mM restores the TSH phospholipid effect. Verapamil (10(-3) M) and Chlorpromazine (10(-3) M) redirect glycerolipid metabolism by increasing PI and phosphatidic acid (PA) synthesis at the expense of other glycerolipids, as phosphatidylcholine (PC) and phosphatidylethanolamine (PE). These results suggest that the "phospholipid effect" is not a result of Ca2+ entry into the thyroid cells. On the contrary, it seems that this increased turnover of PI in "long term" incubations (3 hr). An additive and acute effect of TSH effect is more pronounced when Ca2+ movements 相似文献
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The molecular weight of human transcortin, calculated from the sedimentation coefficient, was found to be 49,500, thus slightly lower than previously reported values. After purification, human transcortin trended to polymerize rapidly, with participation of both non covalent bonds and one disulfide bridge per dimer. The physicochemical parameters, the amino-acid and carbohydrate composition were determined; its stability was studied under different conditions. Preliminary structural studies showed that the N-terminal sequence of the polypeptide chain was: Met-Asp-Pro-Asn-Ala-Ala-Tyr-Val and that the C-terminal amino acid was leucine. 相似文献
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Allium ascalonicum L,在我国的邦名比较混乱,而且它与洋葱、葱的亲缘关系不清。作者认为,它在我国的邦名应规范为胡葱,同时,从性状比较的角度研究胡葱与洋葱、葱之间的亲缘关系。结果表明,胡葱的植物学特征和生物学特性介于洋葱和葱之间。 相似文献
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胡葱与洋葱、葱过氧化物酶同工酶研究及聚类分析 总被引:3,自引:0,他引:3
本文对胡葱与洋葱、葱的功能叶过氧化物酶同工酶电泳图谱分析和聚类分析表明:这三个种及葱的3个交种闻的亲缘关系被区分开来;胡葱与洋葱的亲缘关系比胡葱与大葱的亲缘关系更近。 相似文献
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通过腊叶标本研究、野外观察和文献考证,结合栽培试验,研究了香蒲科水烛(Typha angustifolia L.)花部结构特征,补充描述了该种丝状毛在子房柄上的着生方式、小穗不孕雌花数目等性状特征,观察了在成熟期不同阶段其孕性雌花柱头与小苞片的长度变异。结果显示,水烛孕性雌花小苞片呈宽披针形、匙形或条形,先端褐色,短于柱头,或与柱头近等长或稍长于柱头;子房柄上的丝状毛除少数散生外,多数基部合生呈鞘状或束状,在子房柄下部呈1~4轮排列;小穗不孕雌花常3(~4)枚。研究材料在7月中旬前后雌花小苞片明显短于柱头,随果穗成熟小苞片与柱头近等长。长苞香蒲(T.domingensis Pers.)子房柄上的丝状毛形态和着生方式与水烛中的情况基本一致,但小苞片白色透明,小穗不孕雌花常1(~2)枚。这表明水烛孕性雌花小苞片和柱头的长度比例与不同成熟阶段有关系,不宜作为与长苞香蒲的区别特征,而小穗不孕雌花数目和小苞片颜色等特征对两物种的划分有较重要的意义。 相似文献
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辛夷与木兰名实新考 总被引:4,自引:0,他引:4
辛夷与木兰是中国传统的中药材 ,也是传统的树种名称 ,栽培历史悠久。通过对辛夷与木兰进行认真细致地考证 ,首次提出 :1辛夷 L assonia quinquepeta Buc'hoz是望春玉兰 Yulania biondii(Pam p.) D.L.Fu,不是紫玉兰 Y.liliiflora(Desr.) D.L.Fu;2辛夷药材泛指玉兰属 Yulania Spach树种的干燥花蕾 ,玉兰属植物可统称为辛夷植物 ;3木兰是木莲 Manglietia fordiana Oliv.或黄心夜合 Michelia martinii(H.Lév.) Finet & Gagnep.ex H.Lév.等 ,不为玉兰属树种。纠正了现代有关工具书、植物学专著、药学专著及高等院校教材等广为认同的“辛夷即木兰、木兰即紫玉兰”的错误观点。 相似文献
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普通小麦T型细胞质雄性不育系及其保持系线粒体多肽的电泳比较研究 总被引:12,自引:0,他引:12
应用单向SDS-PAGE和双向IEF-SDS电泳技术对两个品种的普通小麦(T.aestivum L.)T型细胞质雄性不育系及其保持系的线粒体多肽进行了比较研究,结论如下:1.黄化苗期不育系和保持系线粒体多肽在单向SDS-PAGE和双向IEF-SDS电泳行为上无明显差别;2.在孕穗期幼穗线粒体多肽的单向SDS-PAGE图谱上,两个不育系都缺少28Kd多肽带纹,因而不育系和保持系间表现出明显的差异。双向IEF-SDS凝胶电泳证实28Kd带纹实际上是分子量相同而等电点分别为5.58和5.65的两个多肽;3.线粒体基因的表达是具有时空性质的;4.线粒体与T型细胞质雄性不育可能存在着某种特定的关系。 本文还就T型细胞质雄性不育的分子机制进行了探索性讨论。 相似文献
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In rivers, variations in concentrations of many dissolved nutrients occur during spates. Increases are usually attributed
to concentrated point or non-point inputs, and decreases to dilution associated with rainfall. Increased discharge disturbs
sediments and benthic communities, but the effects of such disturbance on nutrient levels are difficult to isolate. Measurements
of nutrient levels over three artificial spates revealed that substantial variations in dissolved organic carbon, dissolved
phosphate, silicate, nitrate, and potassium levels could result from increased discharge in the absence of allochthonous inputs.
Variations were closely related to peaks in suspended solids concentration or water height. Increases in biochemical oxygen
demand and suspended bacteria also occurred.
Variations in phosphate and silicate could be accounted for by a balance between release of ‘sediment interstitial water’
and exchange processes involving suspended and freshly exposed sediment.
An increase in nitrate, during one spate, was probably due to a reduction in the effect of benthic denitrification.
Small peaks in dissolved organic matter concentration were detected over each spate.
We propose that within-stream disturbance is a factor which may contribute to variations in dissolved nutrient concentration
during the rising hydrograph in natural spates. 相似文献
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YANG Qin-Er 《植物分类学报:英文版》2002,40(5):396-405
The somatic chromosome number and detailed chromosome morphology have been studied in ten species of Anemone, one species of Anemoclema, and six species of Clematis, all from China, namely Anemone davidii Franch. (2n=4x= 32), A. stolonifera Maxim. (2n=2x=16), A. flaccida Fr. Schmidt (2n=2x= 14), A. rivularis Buch.-Ham. (2n=2x= 16), A. begoniifiolia lévl. et Vant. (2n=2x= 16), A. hupehensis Lem. f. alba W. T. Wang (2n =2x = 16), A. tomentosa (Maxim.) Péi (2n=2x= 16), A. rupestris Hook. f. et Thoms. (2n=2x= 14), A. trullifolia var. colestina (Franch.) Finet et Gagnep. (2n = 2x = 14), A. trullifolia var. holophylla Diels (2n=2x= 14), A. demissa Hook. f. et Thoms. (2n=2x= 14), Anemoclema glaucifolium (Franch.) W. T. Wang (2n= 2x= 16), Clematis kockiana Schneid. (2n= 2x=16), C. rehderiana Craib. (2n = 2x = 16), C. ranunculoides Franch. (2n = 2x = 16), C. puberula var. ganpiniana(Lévl. et Vant. ) W. T. Wang (2n = 2x = 16), C. brevicaudata DC. (2n= 2x= 16), C. chrysocoma Franch. (2n = 2x = 16). The species of x = 8 in Anemone, and those in Anemoclema and Clematis have very similar karyotypes which consist of five pairs of large median-centromeric (rarely one pair of which are submedian-centromeric) and three pairs of subterminalor terminal-centromeric chromosomes. 相似文献
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The classified sediment with ethanol from sera of nude mice and humans showed a disturbing effect on L1210 cells in vitro and a lifesaving effect on L1210 cell-bearing mice in vivo. This factor was purified more than 2300-fold to a specific activity of approximately 1 X 10(5) U/mg by ethanol classified precipitation, Sephadex G-200 gel filtration, DEAE cellulose ion exchange chromatography with Nacl and pH gradient aqueous solution, and preparative polyacrylamide gel electrophoresis. 相似文献
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国产毛茛科银莲花族十七种植物的细胞学研究 总被引:2,自引:0,他引:2
研究了国产毛茛科银莲花族Trib.Anemoneae 17种植物的染色体数目和核型。10种银莲花属
Anemone L.植物中,1种(西南银莲花A.davidii)为x=8的四倍体(2n=4x=32),5种(匍枝银莲花A.
stolonifera、草玉梅 A.rivularis、卵叶银莲花A .begoniifolia、水棉花A.hupehensis f. alba、大火草A.tomen-
tosa)为x=8的二倍体(2n=2x=16),4种(鹅掌草A.flaccida、湿地银莲花A.rupestris、蓝匙叶银莲花
A.trullifolia var.colestina、拟条叶银莲花A.trullifolia var.holophylla、展毛银莲花A.demissa)为x=7的
二倍体(2n=2x=14)。罂粟莲花Anemoclema glaucifolium 为x=8的二倍体。6种铁线莲属Clematis L.植
物(滇川铁线莲C.kockiana、长花铁线莲C.rehderiana、毛茛铁线莲C.ranunculoides、扬子铁线莲C.
puberula var.ganpiniana、短尾铁线莲C.brevicaudata、金毛铁线莲A.chrysocoma)均为x=8的二倍体。银
莲花属中x=7的种类的核型彼此十分相似,均由6对大型具中部着丝点的染色体和1对具端部着丝点
的染色体组成;x=8的二倍体种类的核型与罂粟莲花属和铁线莲属植物的核型十分相似,均由5对大型 具中部着丝点和3对具端部或近端部着丝点的染色体组成。 相似文献
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D.H. Isaac E.D.T. Atkins S. Stirm 《International journal of biological macromolecules》1981,3(3):165-170
Fibre type X-ray diffraction patterns have been obtained from oriented, semicrystalline films prepared from the sodium salt form of the bacterial capsular polysaccharide of Klebsiella serotype K9. The molecule has a pentasaccharide repeating sequence, with four neutral residues in the backbone and a glucoronic acid side chain. A novel feature of the molecule is the incorporation of α-l-rhamnose residues, one 1,2 linked and two 1,3 linked in the backbone. Analysis of the X-ray diffraction results indicate an extended three-fold helical conformation with an axially projected chemical repeat of 1.377 nm. Both left and right handed helices have been examined using linked atom least squares techniques to optimize the stereochemistry while simultaneously meeting the observed helical parameters. 相似文献