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A gibberellin-regulated gene from wheat with sequence homology to cathepsin B of mammalian cells 总被引:5,自引:0,他引:5
Francisco J. Cejudo George Murphy Catherine Chinoy David C. Baulcombe 《The Plant journal : for cell and molecular biology》1992,2(6):937-948
A previous report described several cDNAs corresponding to mRNAs which accumulated in wheat aleurone layers treated with gibberellic acid (GA) (Baulcombe and Buffard, 1983). The protein sequence deduced from one of these clones (2529) has extensive similarity to the thiol protease, cathepsin B from mammalian cells. Southern analysis of wheat DNA has shown that the 2529 mRNA is encoded by a small family of genes carried on the group 4 chromosome. The nucleotide sequence of a member of the gene family expressed at a low level in aleurone layers and the use of a primer extension assay to identify a clone of a member of the gene family producing an abundant mRNA are reported. The 2529 mRNA accumulates in the scutellum and the aleurone layer of germinating grains where its expression is regulated by GA. In the scutellum the expression was restricted to the parenchyma, suggesting that the 2529 product may have a role other than for mobilization of the endosperm. 相似文献
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Coleoptile and root tips ofTriticum aestivum cv. Arnej 624 and those ofAvena sativa cv. Victory (Svalöf) as well as dry excised embryos ofTriticum aestivum cv. Rival (Svalöf) and those ofArachis hypogaea cv. 34 3A. H. were cultivated in media containing various concentrations of sucrose and growth regulators, like ascorbic acid, indole-3-acetic acid and gibberellin. Growth, differentiation and water uptake of the various explants were determined at regular time intervals. Further, the concentration of the endogenous ascorbic acid in mg./g. fresh weight, as well as the amount of this growth regulator utilized as per cent of the total were determined. Although all the three growth regulators promote growth in the explants, their effect is best felt when sucrose of a higher concentration (1.0 per cent) is added to the medium. In fact, the response to 1.0 per cent sucrose is sometimes as good as a combination of a growth regulator with sucrose, especially in the case of root explants. The results clearly indicate that the biosynthesis of ascorbic acid in the explants is catalyzed by the addition of indole-3-acetic acid as well as gibberellin. Simultaneously, the utilization of ascorbic acid is also appreciably increased by the presence of these growth regulators. Addition of 1.0 per cent sucrose to the medium containing the above mentioned growth regulators augments to a considerable extent not only the concentration of ascorbic acid, but also steps up its utilization. Enhancement of ascorbic acid as well as its increased utilization are correlated with rapid imbibition of water, growth and differentiation. The role of ascorbic acid in growth is discussed; and on the basis of the data presented here it is postulated that: (1) auxin and gibberellin function in the growth process by catalyzing the biosynthesis of ascorbic acid; and (2) that ascorbic acid not only participates in activation of various enzyme systems, but also stimulates the production of adenosine triphosphate by acting as an electron donor in photosynthetic phosphorylation as well as oxidative phosphorylation; (3) that the above action of ascorbic acid creates a favourable redox balance for synthesis of nucleic acids, proteins, enzymeproteins, and cell-wall constituents, thus enabling the processes of cell division and enlargement to proceed at a fast rate; and (4) that the relative rates of cell division and cell enlargement as well as “ageing” will determine the pattern of plant development. 相似文献
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A 32-year-old phenotypic female with a history of nine consecutive abortions each in the first trimester was referred for cytogenetic studies. She was found to have 45,XX,t(22;22) (p11.1;q11.1) chromosomal pattern. The Ag-NOR banding technique showed that the NORs of both the acrocentrics involved in the translocation were deleted and the loss suffered from the elimination was compensated by the increased NOR activity as well as presence of dNOR on other acrocentric chromosomes. 相似文献
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Structural evolution of wheat chromosomes 4A, 5A,and 7B and its impact on recombination 总被引:3,自引:3,他引:0
K. M. Devos J. Dubcovsky J. Dvořák C. N. Chinoy M. D. Gale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(2):282-288
The construction of comparative genetic maps of chromosomes 4Am and 5Am of Triticum monococcum and chromosomes of homoeologous groups 4, 5 and 7 of T. aestivum has provided insight into the evolution of these chromosomes. The structures of chromosomes 4A, 5A and 7B of modern-day hexaploid bread wheat can be explained by a 4AL/5AL translocation that occurred at the diploid level and is present both in T. monococcum and T. aestivum. Three further rearrangements, a 4AL/7BS translocation, a pericentric inversion and a paracentric inversion, have taken place in the tetraploid progenitor of hexaploid wheat. These structural rearrangements and the evolution of chromosomes 4A, 5A and 7B of bread wheat are discussed. The presence of the 4AL/5AL translocation in several Triticeae genomes raises two questions — which state is the more primitive, and is the translocation of mono- or poly-phylogenetic origin? The rearrangements that have occurred in chromosome 4A resulted in segments of both arms having different positions relative to the telomere, compared to 4Am and to 4B and 4D. Comparisons of map length in these regions indicate that genetic length is a function of distance from the telomere, with the distal regions showing the highest recombination. 相似文献
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Role of ascorbic acid in metabolism of rat testis and epididymis in relation to the onset of puberty
The metabolism of ascorbic acid, cholesterol, serum testosterone level and activities of 3Β and 17Β hydroxysteroid dehydrogenases
were studied in testis and Cauda epididymis of prepubertal, pubertal and postpubertal (5, 15, 30, 45, 55 and 60 day old) rats.
The data showed that serum testosterone levels and 3Β and 17Β hydroxysteroid dehydrogenases were increased with the age. The
ascorbic acid metabolism was found to be stabilized in testis at day 30 being comparable with the adult, whereas a spurt in
its metabolism occurred by day 45 and a significant depletion in ascorbic acid content in relation to the passage of the first
wave of spermatozoa through cauda epididymis. The results of this study clearly elucidate that ascorbic acid is involved in
metabolism of testis and epididymis in developing postnatal rats, in relation to the increasing demands for attaining a stable
hormonal milieu, and the onset of puberty and the passage of the first wave of spermatozoa,via the formation of its free radical monodehydroascorbic acid and charge transfer complex mechanism 相似文献
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