ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515796

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Isopenoids are important metabolites in all living cells. In primary metabolisi, they are found in photosynthesis, respiration, growth factors and in cell cycle control. In secondary metabolism, they interfere in plant defense against diseases and its adaptation to environmental conditions. Numerous biotechnological products come from this metabolic pathway such as aroms and essential oil components. Now this biosynthetic pathway is well known as in procaryotic, eucaryotic cells and organels.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515797

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Plants produce a large family of natural compounds, isoprénoids, which are essential for a wide range of physiological functions including plant growth, development and reproduction. Most of enzymes involved in isoprenoid biosynthetic pathways have been characterized and their genes cloned. In the past few years, transgenic plants have been used in order to unravel the molecular mechanisms for regulation of isoprenoid biosynthesis. Various examples of such plants, carrying in addition agronomical advantages, have been reported. In spite of a possible horizontal dispersion of transgenes, such transformation experiments should be able to provide significant results on plant physiology.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515798

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Plant protection requires alternative strategies to control pest insects. Among these strategies, the use of allelochemicals could be focused on two ways involving:

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515799

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The isolation of the isopentenyl diphosphate (IPP) isomerase (EC 5.3.3.2) encoding gene(idi)ofPhaffia rhodozymaby a new and direct selection procedure in a carotenogenicEscherichia colistrain is described. Isopentenyl diphosphate (IPP) isomerase is a key enzyme in the isoprenoid biosynthetic pathway which catalyses the interconversion of the primary five—carbon diphosphate building blocks dimethylallyl diphosphate (DMAPP) and IPP. Our results imply that this method should be generally useful for the isolation of IPP isomerase encoding genes in both genomic and cDNA libraries from other organisms. The structural gene comprises 1294 nucleotides encoding a 28.7 kDa polypeptide of 251 amino acids. Analysis of the nucleotide and amino acid sequence indicates clear homology to IPP isomerases of non—carotenogenic yeasts,Schizosaccharomyces pombe(46%) andSaccharomyces cerevisiae(42%). By high level expression of the heterologous IPP isomerase gene in a recombinantE. colia3-fold increase in lycopene production was achieved. This indicates the potentials of thisidigene to improve carotenoid biosynthesis by metabolic pathway engineering in homologous and heterologous hosts.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515800

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The gibberellins are a group of terpenoid plant hormones with applications in agriculture and brewing. Present in low amounts in plants, they are abundantly produced by some strains of the ascomyceteGibberella fujikuroi.Gibberellin production in this fungus is repressed by nitrogen and, to a less extent, by glucose. A simple screening procedure has allowed a systematic search ofGibberellamutants with alterations in the gibberellin pathway. The pheno- types of these and other mutants indicate indépendant regulations for the biosyntheses of gibberellins and other terpenoids, such as carotenoids or sterols. The recent cloning of the first fungal gibberellin gene, the one coding for kaurene synthase inPhaeosphaeria, will facilitate the molecular characterization of theGibberellagenes involved in gibberellin biosynthesis.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515801

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The study of yeast sensitivity to sterols biosynthesis inhibitors led us to clone theFEN1gene. Strains carrying defective allele ofFEN1gene are resistant to inhibitors of post—squalene biosynthesis steps. Overexpression of this gene causes hypersensitivity to these inhibotors. Other groups have clonedFEN1gene in different physiological contexts. We present here the chromosomal localisation ofFEN 1at the YCR34W locus and results of investigations devoted to unterstand the function of this gene.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515802

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Significance of constitutive and induced terpenoid defences in conifer resistance is briefly presented. Discussion is focused on monoterpenoids and emphasis is on terpenoid mixtures which appear to be more effective in chemical defences. Better knowledge of the mechanism of action of individual ter- penes and about the combined (additive and synergistic) effects of compounds, will have important implications for forest and agricultural management of pests and pathogens.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515803

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We have used mevinolin, an inhibitor of 3-hydroxy-3-methylglutaryl- CoA reductase, to study the importance of mevalonic acid (MVA) for cell cycle progression of tobacco (Nicotiana tabacumL.) BY-2 (TBY-2) cells. Previously we have shown that in principal mevinolin blocks cells mainly at the end of G1 phase, but that cells are sensitive towards the inhibitor at the end of mitosis/entry G1 phase (Hemmerlin & Bach, 1998). The mevinolin—induced cell-cycle arrest was reversed by addition of exogenous MVA. It is shown that blockage of MVA synthesis might lead to variations in intracellular pH, which could be involved in the regulation of cell proliferation. SDS—PAGE analyses of total proteins and GTP—blot analyses indicate mevinolin—induced changes in the pattern, which can be reversed by addition of MVA. In preliminary experiments it has been demonstrated that artificial increase of the cytosolic pH partially released mevinolin—treated cells from the arrest in late G1 phase. A model is presented of how such proteins and pH variations could interact with cell cycle regulation.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515804

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The antifungal saponins, avenacins, found in the roots of oats(Avena sativa)are thought to be responsible for the resistance of oat seedlings to the ‘take-all’ fungusGaeumannomyces graminisvar.tritici.Here, we confirm the belief that avenacin biosynthesis is restricted to the growing tips of oat roots.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515805

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor