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
    Anthranilate synthase forms in plants and cultured cells of Nicotiana tabacum L. (1986)
    Springer
    Planta 168 (1986), S. 214-221 
    Details
    ISSN: 1432-2048
    Keywords: Anthranilate synthase (isoenzymes) ; Daucus (anthranilate synthase) ; Nicotiana (anthranilate synthase) ; 5-Methyltryptophan ; Tissue culture (enzyme forms) ; Tryptophan ; Zea (anthranilate synthase)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco (N. tabacum cv. Xanthi) cell lines contained two forms of anthranilate synthase (AS; EC 4.1.3.27) which could be partially separated by gel-filtration chromatography. One form was resistant to feedback inihibition by 10 μM tryptophan (trp) while the other form was almost completely inhibited by trp at the same concentration. Cell lines selected as resistant to 5-methyltryptophan (5MT) had more of the trp-resistant AS form. Only the trp-sensitive form was detected in plants regenerated from both normal and 5MT-resistant cell lines. Overexpression of the trp-resistant form in 5MT-resistant tobacco cells disappeared during plant regeneration but reappeared when callus was initiated from the leaves of these plants. The trp-sensitive form was localized in the particulate fraction and the trp-resistant form in the cytosol of tobacco cultured cell protoplasts. The trp-resistant form of AS from tobacco had an estimated MW of 200 000, determined by Sephacryl S-200 chromatography, compared to an estimated MW of 150 000 for the trp-sensitive form. The estimated molecular weights of AS from carrot and corn were 160 000 and 150 000, respectively. Analysis of AS activity from the diploid Nicotiana species Nicotiana otophora (chromosome number 2n=24) by high-performance liquid chromatography showed two activity peaks identical in elution time and trp inhibition characteristics to the activity from N. tabacum (chromosome No. 48). Thus the two enzyme forms found in tobacco did not appear to have originated individually from the progenitor species genomes which combined to make up the tobacco genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402966
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Expression of glyphosate resistance in carrot somatic hybrid cells through the transfer of an amplified 5-enolpyruvylshikimic acid-3-phosphate synthase gene (1988)
    Springer
    Molecular genetics and genomics 211 (1988), S. 357-363 
    Details
    ISSN: 1617-4623
    Keywords: Gen amplification ; Glyphosate resistance ; 5-enolpyruvylshikimic acid ; 3-phosphate synthase (EPSPS) ; Protoplast fusion ; Amino acid analogs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A Daucus carota cell line selected as resistant to N-(phosphonomethyl)-glycine (glyphosate) was found to have increased levels of 5-enolpyruvylshikimic acid-3-phosphate synthase (EPSPS) activity of 5.5 times over wild-type carrot and an EPSPS protein level increase of 8.7 times as confirmed by Western hybridization analysis. Southern blot hybridization using a petunia EPSPS probe showed increases in the number of copies of EPSPS genes in the glyphosate-resistant line which correlated with the higher levels of the EPSPS enzyme. The mechanism of resistance to glyphosate is therefore due to amplification of the EPSPS gene. To examine the stability of the amplified genes, cloned lines selected as doubly resistant to Dl-5-methyltryptophan (5MT) and azetidine-2-carboxylate (A2C) were fused with the amplified EPSPS glyphosate-resistant cell line. Somatic hybrids expressed resistances to 5MT in a semidominant fashion while A2C and glyphosate resistance was expressed as dominant, or semi-dominant traits, in a line-specific manner. The hybrid lines possessed additive chromosome numbers of the parental lines used and no double minute chromosomes were observed. The glyphosate-resistant parental line and most somatic hybrids retained the amplified levels of EPSPS in the absence of selection pressure over a 3-year period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Selection of a Nicotiana plumbaginifolia universal hybridizer and its use in intergeneric somatic hybrid formation (1987)
    Springer
    Molecular genetics and genomics 208 (1987), S. 474-480 
    Details
    ISSN: 1617-4623
    Keywords: Azetidine-2-carboxylate resistance ; Glyphosate resistance ; Gene amplification ; D. carota ; Protoplast fusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A Nicotiana plumbaginifolia cell strain carrying a positive (dominant) trait, resistance to azetidine-2-carboxylate (A2C), was selected in strain NX1 which lacked nitrate reductase activity (a negative or recessive trait). This universal hybridizer strain, denoted NXAr, was fused with dextran to a Daucus carota strain, PR, which carried glyphosate (GLP) resistance. A large number of hybrids were selected in a medium with NO 3 - as the sole nitrogen source and A2C as inhibitor, conditions which prevent the growth of both parents. When the selected colonies were then tested for GLP resistance, 93% carried this trait. In addition the hybrid nature was indicated by additive chromosome numbers, both A2C and GLP resistance in suspension cultures, intermediate nitrate reductase activity and the presence of banding patterns for three isozymes which match those of the parents. Southern hybridization analysis using an enolpyruvylshikimic acid-3-phosphate synthase (EPSPS) probe, pMON 6145, also showed the presence of the gene from both parents in the hybrid strains based on restriction length polymorphisms. The PR strain contains increased levels of EPSPS which confers GLPr due to gene amplification. Since the universal hybridizer can be used as a fusion partner with any wild-type line many protoplast fusion studies can be carried out easily.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328142
    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...