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  • systemic lupus erythematosus  (3)
  • Glyphosate resistance  (2)
  • 5-Methyltryptophan  (1)
  • 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
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  • 2
    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
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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Combined Heterozygous Deficiency of the Classical Complement Pathway Proteins C2 and C4 (1997)
    Springer
    Journal of clinical immunology 17 (1997), S. 176-184 
    Details
    ISSN: 1573-2592
    Keywords: Complement deficiency ; classical pathway ; C2 ; C4 ; systemic lupus erythematosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Genetic deficiencies of components of the classical pathway of complement activation are associated with an increased risk for the development of autoimmune and immune complex-mediated diseases. In the present study we report on the molecular and clinical features associated with combined heterozygous C4 and C2 deficiency in 15 individuals investigated within six families. Approximately 30% of the individuals manifested SLE or another autoimmune condition. Heterozygous C2 deficiency was related to a 28-bp deletion in the C2 gene (C2 deficiency type I), in most cases within the HLA-A25 B18 C2Q0 BfS C4A4B2 DR2 haplotype. Among 13 partial C4-deficient haplotypes transmitted, 8 carried C4A*Q0 alleles and 5 C4B*Q0 alleles. In seven cases the C4A*Q0 alleles were associated with a deletion of the C4A/CYP21P genes within the HLA-B8 C2C BfS C4AQ0B1 DR3 haplotype. In three cases, the C4B*Q0 allele was associated with a deletion of the C4B/CYP21P genes within the HLA-B18 C2C BfF1 C4A3BQ0 DR3 haplotype. In the other cases, C4A*Q0 or C4B*Q0 was dependent on as yet uncharacterized defects in the C4 gene or in C4 gene expression. In view of the relatively high frequency of heterozygous C4 deficiency in the normal Caucasian population, the expected frequency of the combined deficiency should approximate 0.001.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1027334716982
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  • 5
    Electronic Resource
    Electronic Resource
    Complete inherited deficiency of the fourth complement component in a child with systemic lupus erythematosus and his disease-free brother in a North African family (1994)
    Springer
    Journal of clinical immunology 14 (1994), S. 273-279 
    Details
    ISSN: 1573-2592
    Keywords: C4 deficiency ; complement ; systemic lupus erythematosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although null alleles of complement C4 genes (C4A *Q0 andC4B *Q0) are frequent in the normal population, the occurrence of two null alleles on the same chromosome is very rare and therefore complete C4 deficiency is exceptional. We describe a 16-year-old North African boy who presented with systemic lupus erythematosus with renal involvement and persistent undetectable classical pathway activity and C4 protein and hemolytic activity in plasma, with normal C3 levels. Similar complement abnormalities were observed in his healthy 12-year-old brother. Complete C4 deficiency was documented in the two brothers by investigation of the family and the lack of C4A and C4B bands upon phenotyping of C4. Southern blot analysis of the C4/CYP21 gene organization in the family indicated that the deficiency resulted from a deletion of the C4B/CYP21A genes associated with nonexpression of a C4A gene. The double-null haplotype was found to be associated with homozygous A2 B17 C2C BFF C4 AQO BQO DR7 HLA haplotype. Thus, similar C4 deficiencies with HLA identity may lead to different clinical presentations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01540980
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  • 6
    Electronic Resource
    Electronic Resource
    Combined homozygous factor H and heterozygous C2 deficiency in an Italian family (1988)
    Springer
    Journal of clinical immunology 8 (1988), S. 50-56 
    Details
    ISSN: 1573-2592
    Keywords: Factor H ; C2 ; complement deficiency ; systemic lupus erythematosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three of four children in a family have homozygous (less than 1% of normal) deficiency of factor H of the complement system and both parents, who are first cousins, are heterozygous for the same defect. The father and two of the H-deficient siblings also have a partial C2 deficiency. One of the children with combined deficiencies is affected by systemic lupus erythematosus with nephritis. No increased susceptibility to infections has been observed in the family. H deficiency is inherited in an autosomal codominant manner and is independently transmitted from C2 deficiency and HLA haplotypes. In the homozygous state it is associated with very low serum concentrations of B and C3, barely demonstrable as activated molecules. C5 is greatly reduced (less than 5%). Also, properdin and C6–9 are decreased. The findings in this family demonstrate that the occurrence of systemic lupus erythematosus in one of the children affected by a combined deficiency of factor H and C2 raises the question whether this pathology is related to the complete factor H or to the heterozygous C2 deficiency. Complete H deficiency is not necessarily accompanied by overt illness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00915156
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