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21.
The red alga Porphyra purpurea (Roth) C. Agardh has a life cycle that alternates between shell-boring, filamentous sporophytes and free-living, foliose gametophytes. The significant morphological differences between these two phases suggest that many genes should be developmentally regulated and expressed in a phase-specific manner. In this study, we prepared and screened subtracted complementary DNA (cDNA) libraries specific for the sporophyte and gametophyte of P. purpurea. This involved the construction of cDNA libraries from each phase, followed by the removal of common clones through subtractive hybridization. Sampling of the subtracted libraries indicated that 8–10% of the recombinant colonies in each library were specific for the appropriate phase. Of 20 putative phase-specific cDNAs selected from each subtracted library, eight unique clones were obtained for the sporophyte and seven for the gametophyte. After confirming their phase-specificities by hybridization to gametophyte and sporophyte messenger RNA, these 15 phase-specific cDNAs were sequenced, and the deduced amino acid sequences were used to search protein databanks. Two proteins encoded by the sporophyte-specific cDNAs and two by the gametophyte-specific cDNAs were identified by their similarity to databank entries. 相似文献
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23.
560 blood samples collected from mentally retarded children in Taipei were karyotypically analyzed for the incidence of fragile X and other chromosome abnormalities. The fragile site at Xq27.3 was observed in 18 patients (3.21%), 11 males and 7 females, out of the 560 blood cultures using M medium. Down syndrome (6.25%), 24 males and 11 females, was the other major category of abnormality. Other abnormalities, including inversion, translocation, deletion, duplication, ring as well as an extra marker chromosome were observed. The overall incidence of chromosomal abnormalities in these children was 14.82%. 相似文献
24.
25.
从崖椒(Zanthoxglum schinifolutm Sieb.et Zucc.)茎的石油醚、二氯甲烷提取物中分离得到8个化合物。经物理常数测定及光谱(UV,IR,MS,NMR)分析鉴定其为(1)白鲜碱(dictamning),(2)茵芋碱(skimmianine),(3)滨蒿内酯(scoparone),(4)崖椒内酯(schinifolin),(5)莨菪亭(scopoletin),(6)7-羟基-8-甲氧基香豆素(7-hydroxy-8-methoxycoumarin),(7)N-甲基弗林辛(N-methylflindersine),(8)β-谷甾醇(β-sitosterol),其中化合物(5)、(6)和(7)为首次从该植物中分离。 相似文献
26.
Yong Qian Wu Timothy Lawrence Jun Qing Guo Patrick M. Woster 《Bioorganic & medicinal chemistry letters》1993,3(12):2811-2816
A pair of -cyano analogues of decarboxylated S-adenosylmethionine (2a and 2b) were synthesized as potential enzyme activated, irreversible inhibitors of the[pyruvoyl enzyme S-adenosylmethionine decarboxylase (AdoMet-DC). Each of these analogues acts as an irreversible inactivator for ADoMet-DC from Escherichia coli (IC50 values of 9 and 50 μM, respectively). These analogues also inactivate human AdoMet-DC, with KI values of 246.6 and 7.2 μM, and kinact values of 0.29 and 0.03 min−1, respectively. 相似文献
27.
Wang Zunxin Wang Xianyu Liu Siqin Yang Ying Li Yang Chen Siyuan Wang Guangpeng Zhang Xincheng Ye Yuxiu Hu Laibao Zhou Qing Wang Feibing Chen Xinhong 《Journal of Plant Growth Regulation》2023,42(1):294-303
Journal of Plant Growth Regulation - Zinc is an important micronutrient for the growth and development of human body and plants. Proper use of nitrogen fertilizer and foliar application of Zn have... 相似文献
28.
J C M?rkeberg H P Sheng R A Huggins 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1992,199(1):68-74
Use of either urine or saliva samples to estimate extracellular water volume was investigated in 10 men using nonradioactive bromide (Br) and in seven newborn piglets using radioactive Br (82Br) and chloride (36Cl). The relation to Br to Cl concentrations in urine enabled an estimation of Br dilution volume from human urine (267 +/- 42 ml/kg, mean +/- SD) that was not significantly different (P = 1.0) from the Br dilution volume calculated from plasma Br concentration (268 +/- 20 ml/kg). Although the Br dilution volume estimated from saliva was not different from that of plasma, the error in the estimates of Br dilution volume from saliva was too large (mean difference, -36 +/- 64 ml/kg) to make its use practical. The data from piglets showed good agreement between 82Br and 36Cl dilution volumes calculated from 4-hr plasma samples (356 +/- 14 ml/kg and 347 +2- 12 ml/kg; P greater than 0.1) and between 82Br dilution volumes calculated from urine 82Br:36Cl and plasma 82Br (360 +/- 31 ml/kg and 356 +/- 14 ml/kg; P greater than 0.1). Extracellular water volume can be estimated in both adult and young animals using the Br dilution volume calculated from urine samples. It requires (i) two urine collections: one before and one 4 to 8 hr after administration of Br; (ii) a measurement or estimate of plasma Cl concentration; and (iii) a correction factor that describes the relationship of the ratio of Br to Cl in urine to that ratio in plasma. 相似文献
29.
Synchronously dividing cultures of the unicellular green alga Scenedesmus obtusiusculus were cultivated for 24 or 70 h in medium high (1000 μM) or low (60 μM) in phosphorus. Aliquots of AlCl3 (0, 37, 74, 111, 148, 185, or 222 μmol) were added daily to 1 l cell suspension at the end of the cell division phase. Algae were also grown in media with different pH, adjusted with HCl, in the absence of AlCl3 .
Effects of Al on cell metabolism vary with the intracellular Al concentration and with the concentration of Al available per cell. When the concentration of phosphorus is low, internal concentrations of Al are high and the chlorophyll content and the net dry matter production per cell increase, whereas the photosynthesis and the cell division are increased. Presence of Al in a low P medium decreases the pH of the medium down to 4.5. There are only small effects of Al in the presence of P, due to precipitation of most of the Al with P in the medium.
Despite the Al-induced decrease of the pH of the culture medium, effects caused by Al cannot be explained as a pH effect. Instead, the Al effect may, at least to some extent, be related to a decrease in availability of P in the metabolism, due to formation of aluminium phosphate inside the cell. 相似文献
Effects of Al on cell metabolism vary with the intracellular Al concentration and with the concentration of Al available per cell. When the concentration of phosphorus is low, internal concentrations of Al are high and the chlorophyll content and the net dry matter production per cell increase, whereas the photosynthesis and the cell division are increased. Presence of Al in a low P medium decreases the pH of the medium down to 4.5. There are only small effects of Al in the presence of P, due to precipitation of most of the Al with P in the medium.
Despite the Al-induced decrease of the pH of the culture medium, effects caused by Al cannot be explained as a pH effect. Instead, the Al effect may, at least to some extent, be related to a decrease in availability of P in the metabolism, due to formation of aluminium phosphate inside the cell. 相似文献
30.
羊角椒辣味物质成份分析 总被引:2,自引:0,他引:2
用紫外光谱法、红外光谱法和高效液相色谱法分析羊角椒中辣味物质纯度与组成,表明辣味物质由辣椒素、二氢辣椒素和降二氢辣椒素组成。 相似文献