Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Origin of hydroxyphytoene derivatives formed in the presence of bleaching herbicides. (1995)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 43 (1995), S. 1701-1704 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf00054a054
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The carotenoid-deficient mutant, C-6E, of Scenedesmus obliquus is blocked at the site of phytoene synthase (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 99 (1997), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In contrast to the wild type strain of Scenedesmus, mutant C-6E synthesized only trace amounts of the carotenoids violaxanthin and lutein during prolonged heterotrophic growth. All other carotenoids and carotenoid precursors, such as phytoene, were undetectable. Additionally, only reduced levels of chlorophyll a and no chlorophyll b were formed. To evaluate the potential site of inhibition in the pathway for carotenoid biosynthesis the enzymatic activities of geranylgeranyl pyrophosphate synthase and phytoene synthase were assayed in cell-free extracts. Both enzymes were highly active in extracts of the wild type but only geranylgeranyl pyrophosphate synthase was active in comparable extracts from mutant C-6E. This observation strongly indicates that the phenotype of C-6E results from either a mutation of the phytoene synthase structural gene or of a regulatory gene involved in expression of this enzyme. Other phenotypic effects on composition and structure of the photosynthetic apparatus are discussed as a secondary consequence of the carotenoid deficiency in the thylakoid membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb00552.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Expression in Escherichia coli and properties of the carotene ketolase from Haematococcus pluvialis (1996)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 140 (1996), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract High level expression of the functional β-carotene ketolase gene bkt from Haematococcus pluvialis occurred in Escherichia coli transformants producing β-carotene or zeaxanthin as a result of the presence of additional carotenoid genes from Erwinia uredovora. Requirement of molecular oxygen for the insertion of the keto group was demonstrated. The final product of this two-step ketolase reaction from β-carotene is canthaxanthin (4,4′-diketo-β-carotene) with the 4-monoketo derivative echinenone as an intermediate. A reaction sequence for the formation of astaxanthin from β-carotene was established based on kinetic data on astaxanthin formation in E. coli transformants carrying the hydroxylase gene crtZ from Erwinia along with bkt. We conclude that the carotenoids zeaxanthin and adonixanthin which accumulate in addition to astaxanthin in this transformant are products of side reactions rather than direct precursors of astaxanthin. The possible mechanisms for the formation of the keto derivatives are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1996.tb08343.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Mild RIP –an alternative method for in vivo mutagenesis of the albino-3 gene in Neurospora crassa (1996)
    Springer
    Molecular genetics and genomics 252 (1996), S. 353-361 
    Details
    ISSN: 1617-4623
    Keywords: Key words Neurospora crassa ; Geranylgeranyl pyrophosphate synthase ; Prenyltransferase ; Repeat-Induced Point mutation ; Carotenoid biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have used a biological phenomenon that occurs in Neurospora crassa, termed Repeat-Induced Point mutation (RIP), to create partially functional mutant alleles of the albino-3 (al-3) gene encoding geranylgeranyl pyrophosphate synthase, an enzyme involved in the biosynthesis of carotenoids and diverse prenylated compounds. A total of 70 RIP-induced al- 3 mutants were identified by their pale albino phenotype, resulting from inactivation of carotenoid biosynthesis. Nucleotide sequence analysis of the al-3 gene in five of the RIP-induced mutants revealed that in each case RIP had introduced no more than six point mutations. The low frequency of RIP mutants (0.42%) and the isolation of only leaky mutants with very few mutations suggest that ascospores containing a heavily mutated al-3 gene do not survive. These results are evidence that the RIP phenomenon, used to inactivate and silence duplicated genes in N. crassa, may be exploited in its mild version as a method of sequence-specific in vivo mutagenesis to obtain functional mutant alleles of Neurospora genes. This mild form of mutagenesis may be particularly advantageous in selecting for leaky mutations in essential Neurospora genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02172999
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Activation and analysis of cryptic crt genes for carotenoid biosynthesis from Streptomyces griseus (1996)
    Springer
    Molecular genetics and genomics 252 (1996), S. 658-666 
    Details
    ISSN: 1617-4623
    Keywords: Key words Carotenoid biosynthesis ; Lycopene ; Isoreniratene ; Streptomyces griseus ; Cryptic genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Genes encoding enzymes with sequence similarity to carotenoid biosynthetic enzymes of other organisms were cloned from Streptomyces griseus JA3933 and transformed into the colourless (non-daunorubicin producing) mutant Streptomyces griseus IMET JA3933/956/2. Cells harbouring these genes showed an orange-red pigmentation, caused by the strongly hydrophobic, membrane-bound lycopene. The cloned fragment (9 kb) contained seven genes, four transcribed in one direction (crtEIBV) and three (crtYTU) transcribed convergently to them. Three of these genes encode polypeptides that resemble geranylgeranylpyrophosphate (GGPP) synthases (CrtE), phytoene synthases (PS) (CrtB) and phytoene dehydrogenases (PDH) (CrtI), respectively, of various bacteria. These enzymes are sufficient for the formation of lycopene. crtE alone was sufficient to induce zeaxanthin formation in an Escherichia coli clone containing the crt gene cluster from Erwinia herbicola deleted for crtE. The combination of crtE and crtB led to formation of phytoene in S. griseus. The putative crtEp promoter region was cloned and mapped by primer extension analysis. In a gel retardation experiment, this fragment was specifically shifted by an unknown protein. CrtY shows similarity to lycopene cyclases that convert lycopene into β-carotene, CrtT resembles various methyltransferases and CrtU a dehydrogenase. We conclude that these genes are functionally intact, but not expressed (cryptic) in the wild-type S. griseus strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02173971
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A higher-plant type ζ-carotene desaturase in the cyanobacterium Synechocystis PCC6803 (1998)
    Springer
    Plant molecular biology 36 (1998), S. 725-732 
    Details
    ISSN: 1573-5028
    Keywords: ζ-Carotene desaturase gene ; J852 ; lycopene ; neurosporene ; phylogeny ; Synechocystis PCC6803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genomic DNA sequence of Synechocystis was analysed for putative ζ-carotene desaturase genes. Two promising candidates slr0940 and slr0033 were found with similarities to the structurally different ζ-carotene desaturase genes from higher plants and Anabaena, respectively. Only the expression product of the analogue to the plant gene, slr0940, was able to mediate the 2-step desaturation of ζ-carotene via neurosporene to lycopene after complementation of this pathway in Escherichia coli. When enzyme reactions were carried out with this protein, activity was obtained with either ζ-carotene or neuroporene as substrates. The in vitro reaction was inhibited by the pyrimidine derivative J852 which is effective as experimental herbicide in plants. The occurrence of two different types of ζ-carotene desaturases among cyanobacteria and the phylogenetic consequences on chloroplast evolution are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005997405431
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Metabolic engineering of the terpenoid biosynthetic pathway of Escherichia coli for production of the carotenoids β-carotene and zeaxanthin (1999)
    Springer
    Biotechnology letters 21 (1999), S. 791-795 
    Details
    ISSN: 1573-6776
    Keywords: β-carotene ; carotenoid production ; engineered E. coli ; terpenoid biosynthesis ; zeaxanthin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Metabolic engineering of the early non-mevalonate terpenoid pathway of Escherichia coli was carried out to increase the supply of prenyl pyrophosphates as precursor for carotenoid production. Transformation with the genes dxs for over-expression of 1-deoxy-d-xylulose 5-phosphate synthase, dxr for 1-deoxy-d-xylulose 5-phosphate reductoisomerase and idi encoding an isopentenyl pyrophosphate stimulated carotenogenesis up to 3.5-fold. Co-transformation of idi with either dxs or dxr had an additive effect on ß-carotene and zeaxanthin production which reached 1.6 mg g−1 dry wt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005547827380
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...