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931.
Robert de Lorimier Sigurd M. Wilbanks Alexander N. Glazer 《Plant molecular biology》1993,21(2):225-237
R-phycocyanin II (RPCII) is a recently discovered member of the phycocyanin family of photosynthetic light-harvesting proteins. Genes encoding the and subunits of RPCII were cloned and sequenced from marine Synechococcus sp. strains WH8020 and WH8103. The deduced amino acid sequences of RPCII were compared to two other types of phycocyanin, C-phycocyanin (CPC) and phycoerythrocyanin (PEC). These three types vary in the composition of their covalently bound bilin prosthetic groups. In terms of amino acid sequence identity RPCII is highly homologous to CPC and PEC, suggesting that the known three-dimensional structures of the latter two are representative of RPCII. Thus the amino acid residues contacting the three bilins of RPCII could be inferred and compared to those in CPC and PEC. Certain residues were identified among the three phycocyanins as possibly correlating with specific bilin isomers. In overall sequence RPCII and CPC are more homologous to one another than either is to PEC. This probably reflects functional homology in the roles of RPCII and CPC in the transfer of light energy to the core of the phycobilisome, a function not attributed to PEC. The genomes of Synechococcus sp. strains WH8020, WH8103 and WH7803 share homologous open reading frames in the vicinity of RPCII genes. The nucleotide sequence extending 3 from RPCII genes in strain WH8020 revealed two open reading frames homologous to components of an CPC phycocyanobilin lyase. These open reading frames may encode a lyase specific for the attachment of phycoerythrobilin to RPCII. 相似文献
932.
The expression of an Arabidopsis acyl carrier protein (ACP) gene promoter has been examined in transgenic tobacco plants by linking it to the reporter gene -glucuronidase (GUS). Fluorometric analysis showed that the ACP gene promoter was most active in developing seeds. Expression was also high in roots, but significantly lower in young leaves and downregulated upon their maturation. Etiolated and light-grown seedlings showed the same level of GUS activity, indicating that this promoter is not tightly regulated by light. Histochemical studies revealed that expression was usually highest in apical/ meristematic zones of vegetative tissues. Young flowers (ca. 1 cm in length) showed GUS staining in nearly all cell types, however, cell-specific patterns emerged in more mature flowers. The ACP gene promoter was active in the stigma and transmitting tissue of the style, as well as in the tapetum of the anther, developing pollen, and ovules. The results provide evidence that this ACP gene is regulated in a complex manner and is responsive to the array of signals which accompany cell differentiation, and a demand for fatty acids and lipids, during organogenesis. 相似文献
933.
934.
Oscar J. M. Goddijn Paula M. van der Duyn Schouten Rob A. Schilperoort J. Harry C. Hoge 《Plant molecular biology》1993,21(5):907-912
A cDNA clone, pMA1949, detects two mRNA species in wheat seedling tissue that are late embryogenesis-abundant (LEA) and dehydration stress-inducible. Sequence analysis of the pMA1949 clone shows it to be a 991 bp partial cDNA encoding a polypeptide of 317 amino acids with homology to two group 3 LEA proteins, carrot (DC8) and a soybean protein encoded by pGmPM2 cDNA. Molecular analysis of the deduced protein reveals a 33 kDa acidic and extremely hydrophilic protein with potential amphiphilic -helical regions. In addition, the protein contains eleven similar, contiguous repeats of 11 amino acids, which are separated by 118 amino acids from two additional and unique repeats of 36 residues each at the carboxyl end of the protein. Comparisons of sequences of reported group 3 LEA proteins revealed that there are two types, separable by sequence similarity of the 11 amino acid repeating motifs and by the presence or absence of a certain amino acid stretch at the carboxyl terminus. Based on resuls from these comparisons, we propose a second type of group 3 LEA proteins, called group 3 LEA (II). 相似文献
935.
The Eip28/29 gene of Drosophila is an example of a tissue- and stage-specific ecdysone-responsive gene. Its diverse patterns of expression during the third larval instar and a synopsis of those patterns in terms of expression groups have been reported previously. Here we have studied the expression (in transgenic flies) of reporter genes controlled by Eip28/29-derived flanking DNA. During the middle and late third instar, most tissues exhibit normal expression patterns when controlled by one of two classes of regulatory sequences. Class A sequences include only 657 Np of 5′ flanking DNA from Eip28/29. Class B sequences include an extended 3′ flanking region and a minimal (≤93 Np) 5′ flanking region. The class B sequences include all those elements known to be important for ecdvsone induction in cultured cells. They are sufficient to direct the normal premetamorphic induction of Eip28/29 in the lymph glands, hemocytes, proventriculus, and Malpighian tubules. This is consistent with our suggestion that Kc cells are derived from embryonic hematopoietic cells. It is remarkable that the epidermis requires only class A sequences. These are sufficient to up-regulate expression at medinstar and to down-regulate expression at metamorphosis. It follows that the epidermis uses EcREs distinct from those that function in Kc cells. It is possible that the Upstream EcRE, which is nearly silent in Kc cells, is active in the epidermis. © 1994 Wiley-Liss, Inc. 相似文献
936.
观察了hFPIL6/2对6.5Gyγ线照射NIH小鼠第10天造血功能恢复的影响。结果表明:照射小鼠连续4d给予hFPIL6/2250μg·kg-1·d-1,其脾重、CFU-8、骨髓有核细胞数及CM-CFU分别比对照组增加59.0%、278.5%、57.9%和138.2%,统计学处理均有显著差异;对此四项指标的改善也明显优于25μg组。另外,250μg剂量组小鼠外周血象30d的动态观察结果表明,hFPIL6/2不但能明显提高红细胞和血红蛋白的最低值,而且能使血小板的恢复提前。提示hFPIL6/2在促进血小板生成和促进红系造血方面可能具有良好的应用前景。 相似文献
937.
应用噬菌体控制工业循环冷却水中有害微生物的研究 总被引:4,自引:0,他引:4
利用噬菌体控制工业循环冷却水系统中有害微生物的研究表明,分离出的9株噬菌体在冷却水培养液中,其杀菌率为85.4%,而在动态模拟培养液中和挂片上,其杀菌率分别为83.3%和70%. 相似文献
938.
本文对938例初生婴儿接种小剂量(10ug×3)乙肝疫苗后3-5年的预防效果进行了随访观察,并以253例初生儿未接种疫苗者作为对照,结果表明,接种组3-5年后抗-HBs阳性率显著高于对照组,HBsAg阳性率则较对照组显著为低。感染保护率86.7%。结果还表明,接种乙肝疫苗3年后加强1次,比不加强者P/N均值显著增高。文章认为初生儿接种小剂量乙肝疫苗有长期免疫效果;接种后3年加强接种1次,可保持较高免疫力。 相似文献
939.
Diane E. Eyer 《Human nature (Hawthorne, N.Y.)》1994,5(1):69-94
A study of the research on postpartum mother-infant bonding shows that results from poorly constructed research programs were
published in major journals and became a part of hospital policy because the bonding concept was politically useful in the
struggle between advocates of natural childbirth and managers of the medical model of birth. The concept was also uncritically
accepted because it was consistent with a longstanding ideology of motherhood that sees women as the prime architects of their
children’s personalities.
Diane Eyer earned her Ph.D. in developmental psychology from the University of Pennsylvania. She is currently writing a book
on the ways in which the concepts of bonding and attachment have affected our understanding of appropriate early childcare. 相似文献
940.
Mohamed S. Dehlawi Amira T. Eldefrawi Mohyee E. Eldefrawi Nabil A. Anis James J. Valdes 《Journal of biochemical and molecular toxicology》1994,9(5):261-268
A light addressable potentiometric sensor was used to measure acetylcholinesterase (AChE) activity in order to evaluate the protective effects of quaternary compounds and NaF against enzyme phosphorylation and aging by two organophosphates. The use of the immobilized AChE made possible the quick removal of reagents (i.e., organophosphate, 2-pralidoxime, and protectant), thereby permitting accurate determination of AChE activity before and after phosphorylation and aging. Paraoxon was 15-fold more potent in inhibiting AChE than DFP, while the percent aging following phosphorylation by diiso-propylfluorophosphate (DFP) was much higher. Sodium fluoride (NaF), the most effective protectant against phosphorylation and aging, and the quaternary ammonium compounds reduced significantly AChE inhibition by DFP and paraoxon, to similar degrees. Even though the percent AChE activity that was lost to aging was reduced by these agents, aging as a percent of phosphorylated AChE was not reduced. Thus, their major effect was in reducing the percent AChE phosphorylation, which consequently resulted in reduction of total aged AChE. The finding that quaternary ammonium compounds protect against phosphorylation is consonant with the proposed presence of the active site of AChE in an aromatic gorge. 相似文献