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331.
Af finis C. hemsleyanae Franch. et Prain, sed caulibus scapiformibus, flori-lus flavis, majoribus, petalo antico basi saccato facile differt.Herba caespitosa circ. 30 cm longa. Rhizoma circ. 5-10 mm longum, 10 mm crassum, radicibus fibrosis, numerosis, fasciculatis. Caulis 1 usque numerosus, scapiformis, simplex, efoliolatus, interdum basi unifoliatus. Folia basalia numerosa, circ. 20 cm longa, petiolis circ. 15 cm longis basi marginato-expansis, plus minu-sve carnosulis, in sicco purpureo-brunneis, laminis circ. 5 cm longis 5-6 cm latis viridibus, subtus glaucescentibus, biternatis, pinnis brevipetiolulatis, pinnulis sessilibus vel subsessilibus, 2.5-3.5 cm longis, 2 - 3 cm latis bitripartitis, segmentis lanccolatis, saepe trilobatis. 相似文献
332.
针对混合家系遗传参数估计,本文在假定公畜方差组分和母畜方差组分相等这一理论基础上,通过对方差分析的期望均方组成分析,提出了新的遗传力估计方法,以及某些特殊情况下的近似估计方法。通过一个估测实例比较了几种遗传力估计方法,结果表明,本文方法与全同胞组分估计最为接近,而且遗传力标准误最小,本文近似估计方法的效果也较好。对各种方法而言,资料越不平衡其差异越大。本文方法可以在一定程度上弥补全同胞分析时,因实际资料的公母畜方差组分差异过大的缺陷,具有实际可行性。此外,由于本文方法是用单因方差分析解决二因方差分析问题,计算更为简便,并可免于计算混合家系平均亲缘相关系数。 相似文献
333.
中国家猪高分辨G—带及模式图 总被引:9,自引:0,他引:9
采用氨甲喋呤或胸苷阻断法使细胞分裂同步化,并结合胰酶G-带技术,对中国7个家猪品种高分辨G-带进行了研究,发现家猪品种间带型基本一致,从而参照人类细胞遗传学命名法的国际体制,提出了中国家猪高分辨G-带标准化核型及模式图,对显带核型界标进行了少许修改,对每对染色体进行了区带划分和描述。单倍染色体组所显示的G-带数目,包括X和Y染色体,巳达444条,近于中期染色体带纹数目的两倍。 相似文献
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337.
Cloning and characterization of a tandemly repeated DNA sequence in the crane family (Gruidae) 总被引:1,自引:0,他引:1
A tandemly repeated DNA sequence possessing a unique PstI site has been characterized in several species of the crane family. The "Pst family" comprises at least 8800 monomer units 187 base pairs (bp) in length and constitutes 0.14% of the genome of the sarus crane (Grus antigone). The array is located in the centromeric heterochromatin of chromosome 2 in the two species where in situ hybridizations of a cloned monomer to metaphase chromosome spreads were carried out. DNA sequence comparisons between five monomer units from G. antigone revealed a high degree of homology between four of the individual repeats, while the fifth was somewhat divergent. The G + C content deduced from the DNA sequence makes it likely that the Pst family constitutes part of a density satellite seen in profiles of crane DNA centrifuged to equilibrium in CsCl. The common occurrence of tandem arrays such as the Pst family, with repeat lengths close to 200 bp, leads us to an hypothesis implicating nucleosomes in the evolution of such families. 相似文献
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339.
Murine transforming growth factor-beta 2 cDNA sequence and expression in adult tissues and embryos 总被引:18,自引:0,他引:18
D A Miller A Lee R W Pelton E Y Chen H L Moses R Derynck 《Molecular endocrinology (Baltimore, Md.)》1989,3(7):1108-1114
Murine transforming growth factor-beta 2 (TGF-beta 2) cDNAs were isolated from cDNA libraries derived from a differentiated murine embryonic carcinoma cell line, PCC3. The composite cDNA sequence is 4267 nucleotides long, including a 1217 nucleotides 5'-untranslated sequence, and encodes a murine TGF-beta 2 precursor of 414 amino acids with 96% identity to its human counterpart. Several consensus polyadenylation sequences are present in the 1807 nucleotides 3'-untranslated sequence. Five TGF-beta 2 mRNA species are observed in the developing mouse fetus and they show different patterns of expression during development. TGF-beta 2 mRNA expression was also examined in adult mouse tissues, in which four of the five RNA species were observed. TGF-beta 2 mRNAs were present in all adult mouse tissues examined, except liver, and was most abundant in placenta, the male submaxillary gland and lung. The patterns of expression suggest a physiological role for TGF-beta 2 both in embryonic development and in the maintenance of adult tissues. 相似文献
340.
Heme prosthetic group required for acetylation of prostaglandin H synthase by aspirin 总被引:1,自引:0,他引:1
The ability of aspirin to acetylate PGH synthase was determined by reacting [3H-acetyl]-aspirin with purified enzyme followed by high pressure liquid chromatography analysis of the protein components of the reaction mixture. Heme-reconstituted enzyme incorporated approximately one acetyl group per 70-kDa subunit, whereas apoprotein incorporated 0.1 acetyl group per subunit. The ability of the heme prosthetic group to enhance acetylation of the protein was correlated with its ability to protect the Arg253-Gly254 peptide bond from cleavage by trypsin. Thus, heme-induced alteration of protein conformation may contribute to the enhanced labeling of Ser506 by aspirin. The present results indicate that irreversible inactivation of prostaglandin H synthase by aspirin occurs only when the heme prosthetic group is bound to the protein. Considering its short in vivo half-life, it is likely that aspirin inactivates only the steady-state fraction of PGH synthase in a cell that is active but not newly synthesized apoprotein. This may contribute to the differential kinetics of inactivation and recovery of PGH synthase activity in platelets and vascular endothelial cells after administration of low dose aspirin as a prophylactic agent against cardiovascular disease. 相似文献