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1.
Hydroxycinnamoyl-CoA:Putrescine Hydroxycinnamoyltransferase in Tobacco Cell Cultures with High and Low Levels of Caffeoylputrescine 总被引:1,自引:0,他引:1
A new hydroxycinnamoyl-CoA:putrescine hydroxycinnamoyltransferase (PHT) was detected in two variant lines of Nicotiana tabacum L. (TX1, TX4) accumulating markedly different levels of caffeoylputrescine. The enzyme accepted only the aliphatic diamines putrescine, cadaverine and 1,3-diaminopropane at a ratio of 100:33:8. Caffeoyl- and feruloyl-CoAs were the best acyl donors. The apparent Km-values for caffeoyl-CoA and putrescine were near 3 and 10 micromolar, respectively, at the pH-optimum of 10.0. PHT activity was quite similar in low producing TX1 and high producing TX4 cells, while some other biosynthetic enzymes (phenylalanine ammonia-lyase, ornithine decarboxylase) were greatly enhanced in TX4 cells, suggesting that PHT does not catalyze the rate-limiting step in hydroxycinnamoylputrescine formation. 相似文献
2.
Characterization of a meta-Fluorotyrosine-Tolerant Cell Culture of Eschscholtzia californica Cham 下载免费PDF全文
A cell line of Eschscholtzia californica selected for meta-fluorotyrosine (MFT) tolerance was found to have 10-fold increased levels of phenylalanine and tyrosine compared to the parent line, while most other amino acids were only increased 2-fold. Tracer experiments with shikimic acid in the presence of MFT showed that the biosynthesis of the aromatic amino acids was not impaired in the tolerant line. Feeding experiments with phenylalanine, tyrosine, or shikimic acid also revealed a reduced turnover of the pools of the aromatic amino acids in the variant. Thus undisturbed de novo biosynthesis of the aromatic amino acids and dilution of toxic effects of MFT by the enlarged pool sizes seemed to be the main reason for the acquired tolerance. Despite the enlarged availability of the precursor tyrosine, formation of the benzophenanthridine alkaloids was enhanced neither in the growth nor in the production medium. 相似文献
3.
Cell cultures ofThalictrum
rugosum released their protoberberine alkaloids into the medium, when cells were transferred to fresh medium lacking phosphate. The nutritional factors required and the impact of the cells' physiological state for the alkaloid excretion were analyzed. Cell cultures, having released their alkaloids into the medium, continued to grow when the alkaloid containing medium was replaced by fresh growth medium. 相似文献
4.
Glycosaminoglycan synthesis is depressed during mitosis and elevated during early G1 总被引:3,自引:1,他引:2 下载免费PDF全文
S F Preston C S Regula P R Sager C B Pearson L S Daniels P A Brown R D Berlin 《The Journal of cell biology》1985,101(3):1086-1093
[35S]Sulfate incorporation was measured in populations of Chinese hamster ovary cells enriched for mitotics, early G1 cells, and interphase monolayers or suspensions. Incorporation was determined by biochemical analysis of extracts and quantitative autoradiography of thick sections. 90% of [35S]sulfate was incorporated into glycosaminoglycan (GAG). Incorporation was depressed fourfold in mitotics and stimulated by from two- to three-fold in early G1 cells relative to mixed interphase cells. GAG synthesis was maintained into late G2. Thus, the rate of GAG biosynthesis was correlated temporally with the detachment and reattachment of cells to substrate. Inhibitors of protein synthesis brought about the rapid arrest of GAG biosynthesis. However, xylosides, which bypass the requirement for core protein, did not bring oligosaccharide sulfation in mitotics to interphase levels. These observations indicate an inhibition of Golgi processing and are consistent with a generalized defect of membrane vesicle-mediated transport during mitosis. 相似文献
5.
Norma L. Trolinder Jerry D. Berlin Joe R. Goodin 《In vitro cellular & developmental biology. Plant》1987,23(11):789-794
Summary A cotton cell suspension culture has been developed that provides unique opportunities for plant biologists to investigate
early developmental events regulating cotton fiber properties, plant cell elongation, and cell wall biogenesis. The suspension
culture was derived from cells of cotton (Gossypium hirsutum L.) ovule callus. These cells undergo the stages of fiber development
previously described for in vivo fiber development. Fibers range in length up to 11 mm and have secondary walls.
Supported by the U.S. Department of Agriculture, Agricultural Research Service, Southern Regional Research Laboratory, New
Orleans, Louisiana, and Cotton Incorporated, Raleigh, North Carolina. 相似文献
6.
7.
The ultrastructural localization of acid mucopolysaccharides in the intestine after irradiation 总被引:2,自引:0,他引:2
J D Berlin 《Radiation research》1968,34(2):347-356
8.
9.
10.
J. Berlin C. Rügenhagen I. N. Kuzovkina L. F. Fecker F. Sasse 《Plant Cell, Tissue and Organ Culture》1994,38(2-3):289-297
This article reviews our present knowledge on the formation of tryptophan derived secondary metabolites in tissue cultures of Peganum harmala. With the presence of -carboline alkaloids and serotonin, P. harmala contains two rather simple, interrelated biosynthetic pathways. The long term disadvantage of low and unstable productivity of P. harmala suspension culture has recently been overcome by establishing highly productive hairy root cultures. The first -carboline alkaloid biosynthetic enzymes, specific for the O-methylation of harmalol and harmol as well as for the oxidation of harmaline to harmine, have been detected in these cultures, and they should thus provide a suitable source for studying the yet unknown initial two enzymatic steps of -carboline alkaloid biosynthesis. Seedlings of P. harmala have also been successfully transformed with constructed strains of Agrobacterium, as demonstrated by the overexpression of a tryptophan decarboxylase gene from Catharanthus roseus in cultures of P. harmala. In such transgenic cultures a large overproduction of serotonin was observed. The relative simplicity of these pathways and the rather easy handling of the cultures could make P. harmala a useful and attractive model system for studying the interaction, regulation and manipulation of secondary pathways in cultured cells.Abbreviations TDC
tryptophan decarboxylase
-
tdc
gene of tryptophan decarboxylase 相似文献