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  • 1990-1994  (253)
  • 1955-1959  (19)
  • 1890-1899
  • 1850-1859
  • Brassica napus
  • somaclonal variation
  • transformation
  • 1
    Electronic Resource
    Electronic Resource
    Plasmid mediated silver resistance in Acinetobacter baumannii (1994)
    Springer
    BioMetals 7 (1994), S. 49-56 
    Details
    ISSN: 1572-8773
    Keywords: Acinetobacter ; conjugation ; curing ; plasmid ; silver uptake ; silver resistance ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Acinetobacter baumannii BL88, an environmental isolate, was resistant to 13 metals and 10 antibiotics. Plumbagin cured resistance to silver, cadmium, antimony, streptomycin and ampicillin at varying frequencies. However, only silver resistance transferred (1 × 10−6 recepient−1) to Escherichia coli K12 during conjugation. Correspondingly there was transfer of a 54 kb plasmid (pUPI199) from A. baumannii BL88. The plasmid transformed E. coli DH5α cells at a frequency of 1 × 10−8 recepient−1. The growth rate of E. coli DH5; (pUPI199) was slower as compared with E. coli DH5α. Plasmid pUPI199 was 76 and 9.6% stable in the host A. baumannii BL88 in the presence and absence of selection pressure, respectively. A. baumannii BL88 was found to accumulate and retain silver whereas E. coli DH5α (pUPI199) effluxed 63% of the accumulated silver ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00205194
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  • 2
    Electronic Resource
    Electronic Resource
    Canonical correlation and reduction of multiple time series (1994)
    Springer
    Annals of the Institute of Statistical Mathematics 46 (1994), S. 625-631 
    Details
    ISSN: 1572-9052
    Keywords: Rank of multiple time series ; transformation ; spectrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract It is shown that a degenerate rankd-variate stationary time series can be reduced to a full rank time series of lower dimension via an orthogonal transformationT provided that ρ, the canonical correlation between past and future of the time series is strictly less than one. Procedures for estimation of rank of the multiple time series,T and testing ρ=1 are outlined, the latter is related to testing the unit root hypothesis in ARMA models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00773471
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  • 3
    Electronic Resource
    Electronic Resource
    Genetic ecology: A new interdisciplinary science, fundamental for evolution, biodiversity and biosafety evaluations (1994)
    Springer
    Cellular and molecular life sciences 50 (1994), S. 429-437 
    Details
    ISSN: 1420-9071
    Keywords: Genetics ; ecology ; DNA-transfer ; conjugation ; transformation ; transduction ; transposons ; dormant cells ; epilithon ; microbial colonisation ; symbiosis ; virus resistance ; biosafety ; release of genes ; insults to humanity ; evolution ; biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Genetic ecology is the extension of our modern knowledge in molecular genetics to studies of viability, gene expression and gene movements in natural environments like soils, aquifers and digestive tracts. In such milieux, the horizontal transfer of plasmid-borne genes between phylogenetically distant species has already been found to be much more frequent than had been expected from laboratory experience. For the study of exchanges involving chromosomally-located genes, more has to be learned about the behaviour of transposons in such environments. The results expected from studies in genetic ecology are relevant for considerations of evolution, biodiversity and biosafety. The role of this new field of research in restoring popular confidence in science and in its biotechnological applications is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01920741
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  • 4
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated transformation of white mustard (Sinapis alba L.) and regeneration of transgenic plants (1994)
    Springer
    Plant cell reports 13 (1994), S. 130-134 
    Details
    ISSN: 1432-203X
    Keywords: Sinapis alba L. ; Agrobacterium tumefaciens ; transformation ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A procedure for the regeneration of fertile transgenic white mustard (Sinapis alba L.) is presented. The protocol is based on infection of stem explants of 7–9 day old plants with an Agrobacterium tumefaciens strain harboring a disarmed binary vector with chimeric genes encoding neomycin phosphotransferase and β-glucuronidase. Shoots are regenerated from callus-forming explants within 3–4 weeks. Under selection, 10% of the explants with transgenic embryonic callus develop into fertile transgenic plants. Rooting shoots transferred to soil yield seeds within 14–16 weeks following transformation. Integration and expression of the T-DNA encoded marker genes was confirmed by histochemical β glucuronidase assays and Southern-DNA hybridization using primary transformants and S1-progeny. The analysis showed stable integration and Mendelian inheritance of trans-genes in transformed Sinapis lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239878
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  • 5
    Electronic Resource
    Electronic Resource
    Stable expression of the GUS reporter gene in chrysanthemum depends on binary plasmid T-DNA (1994)
    Springer
    Plant cell reports 14 (1994), S. 59-64 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium ; transformation ; T-DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three chrysanthemum (Dendranthema grandiflora) cultivars were cocultivated with 2 Agrobacterium tumefaciens strains in combination with 4 pBIN19 derived binary plasmids, all carrying the Nosnptll selection gene and 35Sgus(intron) reporter gene. All binary plasmids transferred DNA to chrysanthemum explants but only pMOG410 gave good stable expression of GUS. This plasmid differs from the other plasmids in 2 aspects: 1) It carries a restored nptll gene and 2) the selection gene is positioned at the left border side of the reporter gene. Cocultivation with AGLO(pMOG410) yielded up to 13 GUS positive shoots per 100 explants. The presence of the gus and nptll gene in recovered shoots was confirmed by PCR and Southern blot analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233300
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  • 6
    Electronic Resource
    Electronic Resource
    Isolation and transformation of rice aleurone protoplasts (1994)
    Springer
    Plant cell reports 13 (1994), S. 394-396 
    Details
    ISSN: 1432-203X
    Keywords: Rice ; α-amylase ; protoplasts ; aleurone ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts isolated from the aleurone have been used extensively in molecular studies focusing on hormone-mediated regulation of gene expression in barley seed. To extend the use of aleurone protoplasts to other species, we have determined the conditions necessary for the isolation of protoplasts from rice aleurone layers of germinated seed. Many of the common cell wall degrading enzymes used in making protoplasts were tested for their ability to release protoplasts from rice aleurone layers. Cellulysin was found to be the most effective. Transformation of these aleurone protoplasts was accomplished using polyethylene glycol and DNA constructs containing the firefly luciferase reporter gene under the control of two different promoters were tested. Luciferase expression was 24-fold greater when the reporter gene was under the control of the CaMV 35S promoter than when the promoter from the alcohol dehydrogenase 1 gene was used. With the isolation and transformation of aleurone protoplasts from rice, it is now possible to investigate molecular events occurring in this tissue during germination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234145
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  • 7
    Electronic Resource
    Electronic Resource
    Hairy roots of Brassica napus: I. Applied glutamine overcomes the effect of phosphinothricin treatment (1994)
    Springer
    Plant cell reports 14 (1994), S. 37-40 
    Details
    ISSN: 1432-203X
    Keywords: Ammonia ; Agrobacterium rhizogenes ; Brassica napus ; glutamine ; glutamine synthetase ; phosphinothricin ; rape
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hairy roots of Brassica napus (rape cv. Giant) were produced by cocultivating leaf and cotyledon explants with Agrobacterium rhizogenes strain A4T. The hairy roots grew prolifically on solid and in liquid media. Incorporation of ammonium sulphate or phosphinothricin (PPT) into the media reduced growth. PPT treatment reduced glutamine synthetase (GS) activity and increased the ammonia content of the hairy roots. We have found that PPT treatment also induces a loss of glutamine from the roots and this may influence root growth. To test this we grew hairy roots in a liquid medium containing 10 mM glutamine. This glutamine treatment overcame the PPT induced suppression of growth but also significantly increased GS activity, reduced ammonia accumulation and increased the levels of glutamate and asparagine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233295
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular improvement of cereals (1994)
    Springer
    Plant molecular biology 25 (1994), S. 925-937 
    Details
    ISSN: 1573-5028
    Keywords: cereals ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014667
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  • 9
    Electronic Resource
    Electronic Resource
    The highly expressed tapetum-specific A9 gene is not required for male fertility in Brassica napus (1994)
    Springer
    Plant molecular biology 24 (1994), S. 97-104 
    Details
    ISSN: 1573-5028
    Keywords: anther ; antisense RNA ; Brassica napus ; male fertility ; tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An antisense approach was used to attempt to determine the function of the highly abundant, tapetum-specific A9 transcript in microsporogenesis. A Brassica napus A9 cDNA clone was linked in sense and antisense orientations to the Arabidopsis thaliana A9 promoter and the resulting chimaeric genes introduced into B. napus. A high proportion of the offspring of B. napus antisense A9 plants had very low or undetectable levels of A9 mRNA. However, these plants set seed and had pollen of normal or near normal viability. Therefore, under the conditions studied, the A9 protein appears not to be essential for male fertility in B. napus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040577
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of a mRNA that accumulates during development of oilseed rape pods (1994)
    Springer
    Plant molecular biology 24 (1994), S. 223-227 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; dehiscence ; dehydrogenase ; pod ; protochlorophyllide reductase ; shatter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dehiscence of oilseed rape pods, commonly known as pod shatter, is a process of agronomic importance that results in seed loss causing yield reductions and carry-over of the crop into the following growing season. In an effort to understand the mechanisms underlying this developmental event, the changes in gene expression that accompany pod shatter have been examined with a view to understanding how the process is regulated. In order to achieve this, a cDNA library was constructed using mRNA extracted from the dehiscence zone of developing pods. Differential screening with non-dehiscence zone cDNA led to the isolation of a pod-specific clone, SAC25, with a transcript size of 1100 nucleotide encoding a predicted polypeptide of 34 kDa. The level of SAC25 mRNA accumulation increased during pod development. The sequence shows no significant homology to others within the databases but has two identifiable amino acid motifs, one is an adenine nucleotide binding site for NAD/FAD dehydrogenases and the other is a conserved feature of the ribitol dehydrogenase family. The amino acid sequence has four putative glycosylation sites and contains four cysteine residues. Genomic Southern analysis indicates that SAC25 may be encoded by a single gene or a small gene family. The function of this mRNA is unknown but possible roles in dehiscence and pod development are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040589
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  • 11
    Electronic Resource
    Electronic Resource
    Identification of conserved domains in the Δ12 desaturases of cyanobacteria (1994)
    Springer
    Plant molecular biology 24 (1994), S. 643-650 
    Details
    ISSN: 1573-5028
    Keywords: Anabaena variabilis ; fatty-acid desaturation ; Synechococcus PCC7002 ; Synechococcus PCC7942 ; Synechocystis PCC6714 ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterial genes for enzymes that desaturate fatty acids at the Δ12 position, designated desA, were isolated from Synechocystis PCC6714, Synechococcus PCC7002 and Anabaena variabilis by crosshybridization with a DNA probe derived from the desA gene of Synechocystis PCC6803. The genes of Synechocystis PCC6714, Synechococcus PCC7002 and A. variabilis encode proteins of 349, 347 and 350 amino acid residues, respectively. The transformation of Synechococcus PCC7942 with the desA genes from Synechocystis PCC6714, Synechococcus PCC7002 and A. variabilis was associated with the ability to introduce a second double bond at the Δ12 position of fatty acids. The amino acid sequence of the products of the desA genes revealed the presence of four conserved domains. Since one of the conserved domains was also found in the amino acid sequences of ω3 desaturases of Brassica napus and mung bean, this domain may play an essential role in the introduction of a double bond into fatty acids bound to membrane lipids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023560
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  • 12
    Electronic Resource
    Electronic Resource
    Directed disruption of the Chlamydomonas chloroplast psbK gene destabilizes the photosystem II reaction center complex (1994)
    Springer
    Plant molecular biology 24 (1994), S. 779-788 
    Details
    ISSN: 1573-5028
    Keywords: Chlamydomonas reinhardtii ; chloroplast ; transformation ; photosystem II ; psbK
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using particle gun-mediated chloroplast transformation we have disrupted the psbK gene of Chlamydomonas reihardtii with an aadA expression cassette that confers resistance to spectinomycin. The transformants are unable to grow photoautotrophically, but they grow normally in acetate-containing medium. They are deficient in photosystem II activity as measured by fluorescence transients and O2 evolution and they accumulate less than 10% of wild-type levels of photosystem II as measured by immunochemical means. Pulse-labeling experiments indicate that the photosystem II complex is synthesized normally in the transformants. These results differ from those obtained previously with similar cyanobacterial psbK mutants that were still capable of photoautotrophic growth (Ikeuchi et al., J. Biol. Chem. 266 (1991) 1111–1115). In C. reinhardtii the psbK product is required for the stable assembly and/or stability of the photosystem II complex and essential for photoautotrophic growth. The data also suggest that the stability requirements of the photosynthetic complexes differ considerably between C. reinhardtii and cyanobacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029859
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  • 13
    Electronic Resource
    Electronic Resource
    A seed-specific Brassica napus oleosin promoter interacts with a G-box-specific protein and may be bi-directional (1994)
    Springer
    Plant molecular biology 24 (1994), S. 327-340 
    Details
    ISSN: 1573-5028
    Keywords: abscisic acid ; ABA-response element ; bi-directional promoter ; Brassica napus ; oleosin ; seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Brassica napus, oleosins are expressed at high levels in the seed during the latter stages of embryo development. The cis-acting regulatory properties of an 872 bp promoter fragment of a B. napus oleosin gene were examined by analysis of β-glucuronidase (GUS) expression in transgenic tobacco plants containing an oleosin promoter-GUS transcriptional fusion. The reporter gene was expressed at high levels only in seeds, specifically in embryo and endosperm tissue and regulated throughout seed development. These data demonstrate that oleosin gene transcription is regulated in a tissue-specific and temporally regulated manner and clearly indicate that oleosin protein expression is co-ordinated primarily at the transcriptional level. Oleosin mRNA was shown to be abscisic acid (ABA) inducible and an ABA-response element in the oleosin promoter was shown to be bound by a protein factor in a sequence-specific manner. Sequence analysis of the oleosin promoter has identified several other putative cis-acting sequences which may direct oleosin gene expression. The presence of a large open reading frame in the bottom strand of the oleosin promoter (ORF2) which encodes a polypeptide similar to the ethylene-induced E4 gene of tomato is reported. A PCR-generated DNA probe containing the ORF2 sequence hybridised with a 1.4 kb transcript in total RNA extracts of a variety of tissues, including leaves and germinated seed cotyledons. This finding suggests that the oleosin gene promoter directs transcription in both directions. It is the first report of a bi-directional nuclear gene promoter in plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020171
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  • 14
    Electronic Resource
    Electronic Resource
    Stable transformation and long-term expression of the gusA reporter gene in callus lines of perennial ryegrass (Lolium perenne L.) (1994)
    Springer
    Plant molecular biology 24 (1994), S. 401-405 
    Details
    ISSN: 1573-5028
    Keywords: Lolium perenne L. ; transformation ; rice gene GOS2 ; long-term GUS expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stable transformation of perennial ryegrass (Lolium perenne L.) was achieved by biolistic bombardment of a non embryogenic cell suspension culture, using the hpt and gusA gene. The transformation yielded on the average 5 callus lines per bombardment (1.4×106 cells). Stable integration of the genes into the plant genome was demonstrated by Southern analysis of DNA, isolated from hygromycin-resistant callus lines. The gusA reporter gene, which was regulated by the constitutive promoter of the rice gene GOS2, was expressed in both transient and stable transformation assays, indicating that this promoter is suitable for expression of a transferred gene in perennial ryegrass. Long-term GUS expression was observed in ca. 40% of the callus lines, whereas the other callus lines showed instability after 6 months and 1 year of culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020178
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  • 15
    Electronic Resource
    Electronic Resource
    Structure and function of selectable and non-selectable transgenes in maize after introduction by particle bombardment (1994)
    Springer
    Plant molecular biology 25 (1994), S. 951-961 
    Details
    ISSN: 1573-5028
    Keywords: Cell biology ; epigenetics ; maize ; transformation ; transgenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Zea mays transformants produced by particle bombardment of embryogenic suspension culture cells of the genotype A188 × B73 and selected on kanamycin or bialaphos were characterized with respect to transgene integration, expression, and inheritance. Selection on bialaphos, mediated by thebar orpat genes, was more efficient than selection on kanamycin, mediated by thenptII gene. Most transformants contained multicopy, single locus, transgene insertion events. A transgene expression cassette was more likely to be rearranged if expression of that gene was not selected for during callus growth. Not all plants regenerated from calli representing single transformation events expressed the transgenes, and a non-selectable gene (uidA) was expressed in fewer plants than was the selectable transgene. Mendelian inheritance of transgenes consistent with transgene insertion at a single locus was observed for approximately two thirds of the transformants assessed. Transgene expression was typically, but not always, predictable in progeny plants-transgene silencing, as well as poor transgene transmission to progeny, was observed in some plant lines in which the parent plants had expressed the transgene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014669
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  • 16
    Electronic Resource
    Electronic Resource
    Expression of mRNA and steady-state levels of protein isoforms of enoyl-ACP reductase from Brassica napus (1994)
    Springer
    Plant molecular biology 26 (1994), S. 155-163 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; Enoyl-ACP reductase ; isoforms ; stearoyl-ACP desaturase ; developmental expression ; seed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of mRNA and the steady-state levels of two-component enzymes of plant fatty acid synthetase (FAS) were studied. Northern analysis of enoyl-ACP reductase (ER) and stearoyl-ACP desaturase (SD) gene expression showed that steady-state levels of both transcripts increase during lipid deposition in the seed reaching a maximum at 29 days after flowering (DAF). The steady-state level of ER message falls very quickly after reaching its maximum, whereas the SD message is longer-lived. The levels of these specific mRNAs in seed are 15–30 times greater than in leaf. Optimum mRNA expression precedes the maximum levels of synthesis of the two proteins, which in turn precede the maximum level of oil. The expression of isoenzymes of ER were examined by two-dimensional western blotting in both leaf and seed tissue. Four enzymes are expressed in both of these tissues; the two most abundant isoforms in seed material are also the most abundant in leaf tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039528
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  • 17
    Electronic Resource
    Electronic Resource
    Cloning of ω3 desaturase from cyanobacteria and its use in altering the degree of membrane-lipid unsaturation (1994)
    Springer
    Plant molecular biology 26 (1994), S. 249-263 
    Details
    ISSN: 1573-5028
    Keywords: desB gene ; desaturase ; fatty acid ; Synechococcus sp. PCC 7942 ; Synechocystis sp. PCC 6803 ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacteria respond to a decrease in temperature by desaturating fatty acids of membrane lipids to compensate for the decrease in membrane fluidity. Among various desaturation reactions in cyanobacteria, the desaturation of the ω3 position of fatty acids is the most sensitive to the change in temperature. In the present study, we isolated a gene, designated desB, for the ω3 desaturase from the cyanobacterium, Synechocystis sp. PCC 6803. The desB gene encodes a protein a 359 amino-acid residues with molecular mass of 41.9 kDa. The desB gene is transcribed as a monocistronic operon that produced a single transcript of 1.4 kb. The level of the desB transcript in cells grown at 22°C was 10 times higher than that in cells grown at 34°C. In order to manipulate the fatty-acid unsaturation of membrane lipids, the desB gene in Synechocystis sp. PCC 6803 was mutated by insertion of a kanamycin-resistance gene cartridge. The resultant mutant was unable to desaturate fatty acids at the ω3 position. The desA gene, which encodes the Δ12 desaturase of Synechocystis sp. PCC 6803, and the desB gene were introduced into Synechococcus sp. PCC 7942. Whilst the parent cyanobacterium can only desaturate membrane lipids at the Δ9 position of fatty acids, the resultant transformant was able to desaturate fatty acids of membrane lipids at the Δ9, Δ12 and ω3 positions. These results confirm the function of the desB gene and demonstrate that it is possible to genetically manipulate the fatty-acid unsaturation of membrane lipids in cyanobacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039536
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  • 18
    Electronic Resource
    Electronic Resource
    Effects of an antisense napin gene on seed storage compounds in transgenic Brassica napus seeds (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1115-1124 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; napin ; antisense ; seed storage protein ; seed storage lipid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To manipulate the quantity and quality of storage components in Brassica napus seeds, we have constructed an antisense gene for the storage protein napin. The antisense gene was driven by the 5′-flanking region of the B. napus napin gene to express antisense RNA in a seed-specific manner. Seeds of transgenic plants with antisense genes often contained reduced amounts of napin. In some transgenic plants, no accumulation of napin was observed. However, the total protein content of transgenic and wild-type seeds did not differ significantly. Seeds lacking napin accumulated 1.4 to 1.5 times more cruciferin than untransformed seeds, although the oleosin content was not affected. Fatty acid content and composition in the seeds of transgenic plants were also analyzed by gas chromatography. Though the total fatty acid content of the transformants was the same as that of non-transformants, there was a reduction in 18:1 contents and a concomitant increase of 18:2 in seeds with reduced napin levels. This observed change in fatty acid composition was inherited in the next generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040693
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  • 19
    Electronic Resource
    Electronic Resource
    Functional complementation of a yeast vesicular transport mutation ypt1-1 by a Brassica napus cDNA clone encoding a small GTP-binding protein (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1725-1735 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; heterologous expression ; Rab/Ypt family ; small GTP-binding protein ; vesicular transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone (bra) encoding a small GTP-binding protein was isolated from Brassica napus by screening a root cDNA library with a degenerate oligonucleotide probe that corresponds to a highly conserved GTP-binding domain of the Ras superfamily. Sequence analysis shows that the clone contains an open reading frame of 219 amino acid residues with the estimated molecular mass of 24379 Da and this coding region contains all the conserved motifs of the Ras superfamily. The deduced amino acid sequence of the bra gene is most closely related to the Ypt/Rab family that functions in the vesicular transport (46% and 47% amino acid identity to the yeast Ypt1 and to the human Rab1, respectively) and is more distantly related to the other Ras-related families. The protein encoded by the bra gene, when expressed in Escherichia coli, shows the ability to bind GTP. Furthermore, when the bra gene is introduced into Saccharomyces cerevisiae under the regulation of the yeast GAL1 promoter, the gene can complement the temperature-sensitive yeast mutation ypt1-1 that has defects in vesicular transport function. The amino acid sequence similarity and the functional complementation of the yeast mutation suggest that this gene is likely to be involved in the vesicular transport in plants. Genomic Southern analysis shows that this gene is a member of a small gene family in Brassica napus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019487
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  • 20
    Electronic Resource
    Electronic Resource
    Cotton (Gossypium hirsutum L.) pollen-specific polygalacturonase mRNA: tissue and temporal specificity of its promoter in transgenic tobacco (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1989-1993 
    Details
    ISSN: 1573-5028
    Keywords: polygalacturonase ; pollen-specific promoter ; cotton ; transgenics ; transformation ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene (G9) expressed during late microsporogenesis in cotton (Gossypium hirsutum L.) was isolated. Sequence analysis of the cDNA (1.3 kb) as well as the gene (2.6 kb) revealed an open reading frame of 1233 bases encoding a protein of 43.9 kDa. The coding region of the gene is interrupted by three introns. Northern analysis of the RNA from developing anthers showed that the transcripts appear 12 days before anthesis and that the maximal concentration of RNA occurs in pollen on the day of anthesis. This pattern of gene expression suggests functions in post-anthesis events. Sequence comparisons with other known plant genes indicated that G9 is homologous to polygalacturonases. The G9 promoter conferred tissue and temporal specificity of β-glucuronidase (GUS) expression in transgenic tobacco plants. Thus, the G9 promoter can be used to drive gene expression in homologous as well as heterologous plants in a tissue-specific manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019509
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  • 21
    Electronic Resource
    Electronic Resource
    Expression of the tobacco Tnt1 retrotransposon promoter in heterologous species (1994)
    Springer
    Plant molecular biology 26 (1994), S. 393-402 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Brassica napus ; gene expression ; Nicotiana tabacum ; retrotransposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of the tobacco (Nicotiana tabacum) retrotransposon Tntl has previously been shown to be strongly regulated and driven from the 5′ long terminal repeat (LTR). We report here that the Tntl LTR can promote activity of the β-glucuronidase (GUS) reporter gene in two heterologous species of the Brassicaceae family, namely rapessed (Brassica napus) and Arabidopsis thaliana. The translational LTR-GUS fusion was active in transient expression studies performed with tobacco and rapeseed protoplasts, indicating that the LTR sequences are recognized in heterologous species. Our results also showed that Tntl LTR-promoted GUS expression in transgenic Arabidopsis is strongly regulated, and that, in contrast to tobacco, hormonal activation plays a significant role in the expression of the Tntl LTR in Arabidopsis. LTR sequences were shown to be more effective than the CaMV 35S enhancer region in transient expression studies performed with tobacco or rapessed protoplasts; and substitution of the LTR sequences upstream from the major transcriptional start with the CaMV 35S enhancer region gave high levels of expression in transgenic tobacco and Arabidopsis leaves, suggesting that a Tntl element with similar substitutions in its 5′ LTR might be suited for gene-tagging experiments in heterologous species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039548
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  • 22
    Electronic Resource
    Electronic Resource
    Molecular analysis of two Brassica napus genes expressed in the stigma (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1217-1222 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; pistil ; stigma ; cDNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A partial cDNA clone, Pis 63, corresponding to a mRNA highly expressed in Brassica napus pistils, was isolated by differential screening. PCR was used to complete the Pis 63 sequence (Pis 63-1) and to obtain the sequence of another related cDNA (Pis 63-2). Northern blot and in situ analyses demonstrated that these transcripts are expressed in the stigma throughout flower development. Pis 63-1 and Pis 63-2 display similarity to a cotton fibre cDNA clone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040703
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  • 23
    Electronic Resource
    Electronic Resource
    Expression of the BnmNAP subfamily of napin genes coincides with the induction of Brassica microspore embryogenesis (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1711-1723 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; microspore embryogenesis ; napin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Brassica napus cv. Topas microspores can be diverted from pollen development toward haploid embryo formation in culture by subjecting them to a heat stress treatment. We show that this switch in developmental pathways is accompanied by the induction of high levels of napin seed storage protein gene expression. Changes in the plant growth or microspore culture conditions were not by themselves sufficient to induce napin gene expression. Specific members of the napin multigene family were cloned from a cDNA library prepared from microspores that had been induced to undergo embryogenesis. The majority of napin clones represented three members (BnmNAP2, BnmNAP3 and BnmNAP4) that, along with a previously isolated napin genomic clone (BngNAP1), constitute the highly conserved BnmNAP subfamily of napin genes. Both RNA gel blot analysis, using a subfamily-specific probe, and histochemical analysis of transgenic plants expressing a BngNAP1 promoter-β-glucuronidase gene fusion demonstrated that the BnmNAP subfamily is expressed in embryogenic microspores as well as during subsequent stages of microsporic embryo development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019486
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  • 24
    Electronic Resource
    Electronic Resource
    Production of fertile transgenic maize by electroporation of suspension culture cells (1994)
    Springer
    Plant molecular biology 24 (1994), S. 51-61 
    Details
    ISSN: 1573-5028
    Keywords: Zea mays L. ; transformation ; electroporation ; bar ; phosphinothricin acetyltransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fertile, transgenic maize plants were generated by electroporation of suspension culture cells that were treated with a pectin-degrading enzyme. Electroporation of cells from two different suspension cultures, one derived from A188 X B73 and one derived from a B73-related inbred, with a plasmid containing the bar gene, resulted in high-frequency recovery of stably transformed callus lines. Plants were regenerated from thirteen transformed callus lines and transmission of bar to progeny was demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040573
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  • 25
    Electronic Resource
    Electronic Resource
    Molecular cloning of a cDNA fromBrassica napus L. for a homologue of acyl-CoA-binding protein (1994)
    Springer
    Plant molecular biology 25 (1994), S. 917-920 
    Details
    ISSN: 1573-5028
    Keywords: acyl-CoA-binding protein ; Brassica napus ; diazepam-binding inhibitor protein ; linkage map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA encoding an acyl-CoA-binding protein (ACBP) homologue has been cloned from a λgt11 library made from mRNA isolated from developing seeds of oilseed rape (Brassica napus L.). The derived amino acid sequence reveals a protein 92 amino acids in length which is highly conserved when compared with ACBP sequences from yeast, cow, man and fruit fly. Southern blot analysis ofBrassica napus genomic DNA revealed the presence of 6 genes, 3 derived from theBrassica rapa parent and 3 fromBrassica oleracea. Northern blot analysis showed that ACBP genes are expressed strongly in developing embryo, flowers and cotyledons of seedlings and to a lesser extent in leaves and roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028886
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  • 26
    Electronic Resource
    Electronic Resource
    Hairy roots of Brassica napus: II. Glutamine synthetase overexpression alters ammonia assimilation and the response to phosphinothricin (1994)
    Springer
    Plant cell reports 14 (1994), S. 41-46 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium rhizogenes ; Brassica napus ; glutamine synthetase ; phosphinothricin ; rape ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hairy roots of Brassica napus (rape cv. Giant) have been produced that contain the cytosolic glutamine synthetase (GS) gene from Glycine max (soybean). Leaf explants were cocultivated with Agrobacterium rhizogenes strain A4T harbouring the binary vector pLN16. This vector was constructed by inserting a soybean cytosolic GS cDNA into the multiple cloning site of pGA643, placing it under the control of the CaMV promoter. In addition, the T-DNA region of pLN16 contained a NPTII gene for selection of transformed cells. Transgenic hairy roots grew prolifically on hormone-free media containing a selective level of kanamycin. Southern and northern analyses confirmed the presence of soybean GS DNA and transcripts, respectively. These transformed hairy roots also have a greater abundance of the GS polypeptide, approximately 3–6 fold greater GS activity and lower levels of endogenous ammonia. Hairy roots provide a useful system for studying responses to phosphinothricin (PPT). Hairy roots grown in media containing PPT had lower GS activity, greater ammonia accumulation and slower growth than controls. The presence of the soybean GS gene in the hairy roots reduced these PPT-induced effects and resulted in higher GS activity, lower ammonia levels and faster growth than in PPT-treated controls. Greater tolerance of PPT was also seen in shoots regenerated from the hairy roots displaying elevated levels of GS activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233296
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  • 27
    Electronic Resource
    Electronic Resource
    Discrimination among cultivars of rapeseed (Brassica napus L.) using DNA polymorphisms amplified from arbitrary primers (1994)
    Springer
    Theoretical and applied genetics 87 (1994), S. 697-704 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Cultivar identification ; RAPDs ; Rapeseed ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RAPDs (Randomly Amplified Polymorphic DNAs) were used to discriminate among 23 cultivars of oilseed rape (Brassica napus) selected from several breeding programs. A set of 100 random sequence 10-mer primers were tested, of which 70 produced bands and 22 showed evidence of polymorphism. A selection of six primers produced 23 polymorphic bands of between 300 to 2200 base pairs in size, sufficient to distinguish between the cultivars. An analysis of seed of five cultivars obtained from four different sites showed stability of banding pattern over source of seed. The analysis was repeated using four different thermocyclers, each of which produced the same band pattern. UPGMA cluster analysis indicates that the relationships among some of the cultivars is closer for those from the same breeding program than for those from different programs. The results of this study show that RAPDs can be used as a method of identification for oilseed rape cultivars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222895
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  • 28
    Electronic Resource
    Electronic Resource
    Evaluation of RFLP and RAPD markers in a comparison of Brassica napus breeding lines (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 123-128 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; RFLP markers ; RAPD markers ; Genetic distance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RFLP and RAPD markers were evaluated and compared for their ability to determine genetic relationships in a set of three B. napus breeding lines. Using a total of 50 RFLP and 92 RAPD markers, the relatedness between the lines was determined. In total, the RFLP and the RAPD analysis revealed more than 500 and 400 bands, respectively. The relative frequencies of loci with allele differences were estimated from the band data. The RFLP and RAPD marker sets detected very similar relationships among the three lines, consistent with known pedigree data. Bootstrap analyses showed that the use of approximately 30 probes or primers would have been sufficient to achieve these relationships. This indicates that RAPD markers have the same resolving power as RFLP markers when used on exactly the same set of B. napus genotypes. Since RAPD markers are easier and quicker to use, these markers may be preferred in applications where the relationships between closely-related breeding lines are of interest. The use of RAPD markers in fingerprinting applications may, however, not be warranted, and this is discussed in relation to the reliability of RAPD markers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222404
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  • 29
    Electronic Resource
    Electronic Resource
    Genetic diversity of oilseedBrassica napus germ plasm based on restriction fragment length polymorphisms (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 662-668 
    Details
    ISSN: 1432-2242
    Keywords: Oilseed rape ; Brassica napus ; Restriction fragment length polymorphism ; Genetic diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oilseed rape (Brassica napus) is an important oilseed crop worldwide. Cultivars have been developed for many growing regions, however little is known about genetic diversity inB. napus germ plasm. The purpose of the research presented here was to study the genetic diversity and relationships ofB. napus accessions using restriction fragment length polymorphisms (RFLPs). Eighty threeB. napus accessions were screened using 43 genomic DNA clones which revealed 161 polymorphic fragments. Each accession was uniquely identified by the markers with the exception of the near-isogenic cvs ‘Triton’ and ‘Tower’. The RFLP data were analyzed by cluster analysis of similarity coefficients and by principal component analysis. Overall, there were three major groups of cultivars. The first group included only spring accessions, the second mostly winter accessions and the third, rutabagas and oilseed rape accessions from China and Japan. These results indicate that withinB. napus, winter and spring cultivars represent genetically distinct groups. The grouping of accessions by cluster analysis was generally consistent with known pedigrees. This consistency included the grouping of lines derived both by backcrossing or self-pollination with their parents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01253968
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  • 30
    Electronic Resource
    Electronic Resource
    Identification of RAPD markers linked to a fertility restorer gene for theOgura radish cytoplasmic male sterility of rapeseed (Brassica napus L.) (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 741-748 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Raphanus sativus ; Ogura cytoplasmic male-sterility restorer gene ; Bulked segregant analysis ; RAPD markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bulked segregant analysis was employed to identify random amplified polymorphic DNA (RAPD) markers linked to the restorer gene (Rfo) used in theOgura radish cytoplasmic male sterility of rapeseed. A total of 138 arbitrary 10-mer oligonucleotide primers were screened on the DNA of three pairs of bulks, each bulk corresponding to homozygous restored and male sterile plants of three segregating populations. Six primers produced repeatable polymorphisms between paired bulks. DNA from individual plants of each bulk was then used as a template for amplification with these six primers. DNA polymorphisms generated by four of these primers were found to be completely linked to the restorer gene with the polymorphic DNA fragments being associated either with the fertility restorer allele or with the sterility maintainer allele. Pairwise cross-hybridization demonstrated that the four polymorphic DNA fragments did not share any homology. Southern hybridization of labelled RAPD fragments on digested genomic DNA from the same three pairs of bulks revealed fragments specific to either the male sterile bulks or to the restored bulks and a few fragments common to all bulks, indicating that the amplified sequences are low copy. The four RAPD fragments that were completely linked to the restorer locus have been cloned and sequenced to develop sequence characterized amplified regions (SCARs). This will facilitate the construction of restorer lines used in breeding programs and is the first step towards map-based cloning of the fertility restorer allele.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01253979
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  • 31
    Electronic Resource
    Electronic Resource
    A simple method to estimate the percentage of hybridity in canola (Brassica napus) F1 hybrids (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 853-858 
    Details
    ISSN: 1432-2242
    Keywords: Polymerase chain reaction ; Random amplified polymorphic DNA ; Self-incompatibility ; Brassica campestris ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have developed an efficient PCR-based system that uses RAPD markers for the certification of F1 hybrids of canola. These markers were selected by screening five parental lines used in three crosses X, Y and Z with 131, 131 and 322 primers respectively. Stable DNA fragments that were homozygous and specific to the male inbreds were used to certify F1 hybrid populations. The hybrid production system was based on self-incompatibility (SI) alleles that prevent self-pollination of the female parent. The efficiency of two S-alleles was compared under both field and greenhouse conditions. The percentage of hybridity was estimated in different F1 populations. We found a significant difference between the two alleles for their efficiency in controlling selfing; both alleles were stable under greenhouse conditions, one allele appeared less reliable under field conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224508
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  • 32
    Electronic Resource
    Electronic Resource
    RFLP mapping of Brassica napus using doubled haploid lines (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 615-621 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Doubled haploid ; Linkage map ; Restriction fragment length polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The combined use of doubled haploid lines and molecular markers can provide new genetic information for use in breeding programs. An F1-derived doubled haploid (DH) population of Brassica napus obtained from a cross between an annual canola cultivar (‘Stellar’) and a biennial rapeseed (‘Major’) was used to construct a linkage map of 132 restriction fragment length polymorphism loci. The marker loci were arranged into 22 linkage groups and six pairs of linked loci covering 1016 cM. The DH map was compared to a partial map constructed with a common set of markers for an F2 population derived from the same F1 plant, and the overall maps were not significantly different. Comparisons of maps in Brassica species suggest that less recombination occurs in B. napus (n = 19) than expected from the combined map distances of the two hypothesized diploid progenitors, B. oleracea (n = 9) and B. rapa (n=10). A high percentage (32%) of segregating marker loci were duplicated in the DH map, and conserved linkage arrangements of some duplicated loci indicated possible intergenome homoeology in the amphidiploid or intragenome duplications from the diploid progenitors. Deviation from Mendelian segregation ratios (P 〈 0.05) was observed for 30% of the marker loci in the DH population and for 24% in the F2 population. Deviation towards each parent occurred at equal frequencies in both populations and marker loci that showed deviation clustered in specific linkage groups. The DH lines and molecular marker map generated for this study can be used to map loci for agronomic traits segregating in this population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222456
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  • 33
    Electronic Resource
    Electronic Resource
    Inbreeding depression and dominance-suppression competition after inbreeding in rapeseed (Brassica napus) (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 321-323 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Inbreeding ; Inbreeding depression ; Line variation ; Competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rapeseed plants, of the summer annual variety Topas, that had been selfed twice consecutively were compared to outcrossed half-sibs for inbreeding depression in a rapeseed population at mating equilibrium. The effect of dominance-suppression competition was included in the effect of inbreeding. Both female-and male-fitness characters showed significant inbreeding depression. Biomass decreased 17% with inbreeding and was highly correlated with seed weight. The total number of flowers decreased 15% with inbreeding. There was a significant effect of lines. The possible importance of experimental design in studies that estimate inbreeding depression is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223639
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  • 34
    Electronic Resource
    Electronic Resource
    Intergeneric hybridization between Brassica napus and Sinapis pubescens, and the cytology and crossability of their progenies (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 540-544 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Crossability ; Cytogenetics ; Intergeneric hybridization ; Sinapis pubescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cytological possibility of gene transfer from Sinapis pubescens to Brassica napus was investigated. Intergeneric hybrids between Brassica napus (2n = 38) and Sinapis pubescens (2n = 18) were produced through ovary culture. The F1 hybrids were dihaploid and the chromosome configurations were (0–1) III + (2–11) II + (5–24) I . One F2 plant with 38 chromosomes was obtained from open pollination of the F1 hybrid. Thirty-one seeds were obtained from the backcross of the F2 plant with B. napus. Five out of seven plants had 38 chromosomes, and the pollen stainability ranged from 0% to 81.4%. In the B2 plants obtained from the backcross of B1 plants with B. napus, 66.7% of the plants examined had 38 chromosomes. S. pubescens may become a gene source for the improvement of B. napus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222445
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  • 35
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    Electronic Resource
    Initial acytokinesis during leaf protoplast culture of dihaploid and tetraploidSolanum tuberosum and diploidS. bulbocastanum (1994)
    Springer
    Potato research 37 (1994), S. 413-421 
    Details
    ISSN: 1871-4528
    Keywords: somaclonal variation ; chromosome number ; potato ; polyploidization ; aneuploidization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf protoplasts of dihaploid (2n=2x=24) and tetraploid (2n=4x=48)Solanum tuberosum, and diploidS. bulbocastanum (2n=2x=24) were cultured in liquid medium. The cultures were studied for early karyological changes during their development. Giemsa staining of spread preparations revealed extremely low percentages of protoplasts developing into calli with the parental chromosome number, and high percentages of acytokinetic cells. The nuclear divisions within a cell were synchronous which allowed the occurrence of spindle interaction, resulting in nuclear poly- and aneuploidization. Although polyploidization was also found in uninucleate cells, a major increase in the formation of true-to-type calli would certainly be established by the improvement of early cross wall formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02358355
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  • 36
    Electronic Resource
    Electronic Resource
    T-DNA-insert-independent mutations induced in transformed plant cells duringAgrobacterium co-cultivation (1994)
    Springer
    Transgenic research 3 (1994), S. 317-325 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium ; mutagenesis ; Nicotiana plumbaginifolia ; nitrate reductase ; ploidy ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transformation frequencies were determined for 1n, 2n, and 4n Nicotiana plumbaginifolia protoplast cultures inAgrobacterium-mediated gene transfer experiments. An unexpected large drop (50%) in plating efficiencies was observed in the non-selected (control) 1n populations after transformation treatment with virulent strains. This effect was not observed in the 2n or 4n cultures or in the 1n cultures when treated with avirulent bacteria. The mortality was disproportionally high and could not be explained by the low (0.1–0.5%) transformation efficiency in the 1n population, indicating mutagenesis of the cell populations independently from the T-DNA insertions. Mutagenesis was also indicated in gene tagging experiments where nitrate reductase-deficient (NR−) mutants were selected from haploidNicotiana plumbaginifolia protoplasts, as well as from leaf disc cultures or protoplasts of diploid plants that were heterozygotic for a mutation either in the NR apoenzyme gene (nia/wt) or one of the molybdenum-containing cofactor genes (cnxA/wt), afterAgrobacterium co-cultivation. The chlorate-resistant isolates were tested for the T-DNA-specific kanamycin resistance trait only after NR-deficiency had been established. Thirty-nine independent NR-deficient mutants were analysed further by Southern blot hybridization. There was no indication of integrated T-DNA sequences in the mutated NR genes, despite the fact that NR-deficient cells were found more frequently in cell populations which became transformed during the treatment than in the populations which did not. These observations suggest that transformation-competent cells undergo mutagenesis during theAgrobacterium gene transfer process not only as a result of stable integration events, but also through accompanying events that do not result in major changes in the mutated loci. The nature of these changes at the molecular level remains to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973592
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  • 37
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    Electronic Resource
    An assessment of gene transfer by pollen from field-grown transgenic potatoes to non-transgenic potatoes and related species (1994)
    Springer
    Transgenic research 3 (1994), S. 216-225 
    Details
    ISSN: 1573-9368
    Keywords: Solanum tuberosum ; genetic modification ; transformation ; gene transfer ; genetic isolation ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Information on the extent of transgene dispersal by pollen to adjacent potato plots and to related weed species is an important requisite for risk assessment; a procedure followed before novel transgenic plants are evaluated under field conditions. The purpose of the investigation was to determine the frequency of cross-pollination between potato (Solanum tuberosum) plants at different distances, using a kanamycin resistnace transgene (nptII) as a selectable marker. All potato plants were from the variety Désirée. Non-transgenic potato plants, used as potential recipients of transgene-containing pollen, were planted in 12 sub-plots, at distances of 0–20 m from the nearest transgenic potato plants. Seeds harvested from the non-transgenic plants were screened for resistance to kanamycin, and molecular methods were used to confirm that resistant progeny contained thenptII gene. Where transgenic and non-transgenic potato plants were in alternate rows (leaves touching), 24% of seedlings from the non-transgenic parent plants were kanamycin-resistant. Comparable seedlings from plants at up to 3 m distance had a resistance frequency of 2%, at 10 m the frequency was 0.017% and at 20 m no resistant progeny were observed. Plants of the weed speciesS. dulcamara andS. nigrum were also planted close to the transgenic potatoes to test for evidence of hybridization, and no kanamycin-resistant seedlings were observed among progeny fromS. dulcamara andS. nigrum. This investigation provided evidence that the extent of gene dispersal from transgenic potatoes to non-transgenic potatoes falls markedly with increasing distance, and is negligible at 10 m. There was, also, no evidence of transgene movement from potato toS. dulcamara andS. nigrum under field conditions. These data will be valuable in defining genetic isolation procedures for the early field evaluation and the use of novel transgenic potato genotypes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02336774
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  • 38
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    Electronic Resource
    Opportunities for gene transfer from transgenic oilseed rape (Brassica napus) to related species (1994)
    Springer
    Transgenic research 3 (1994), S. 263-278 
    Details
    ISSN: 1573-9368
    Keywords: Brassica napus ; oilseed rape ; transgenic plants ; interspecific hybridization ; gene transfer ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Before novel transgenic plant genotypes are grown outside containment facilities and evaluated under field conditions, it is necessary to complete a risk assessment to consider the possible consequences of that release. An important aspect of risk assessment is to consider the likelihood and consequences of the transgene being transferred by cross-pollination to related species, including other crops, weeds and ruderal populations. The purpose of this report is to review the literature to assess the ease with whichBrassica napus can hybridize with related species. The evidence for hybridization is considered at three levels: a) by open pollination, b) by hand pollination and c) by the use ofin vitro ovule and embryo rescue techniques; and also examines the fertility and vigour of the F1, F2 and backcross generations. Four species are reported to hybridize withB. napus by open pollination:B. rapa andB. juncea using fully fertile parents; andB. adpressa andR. raphanistrum using a male-sterileB. napus parent. Seventeen species are reported to form hybrids (including the four species above) withB. napus when pollination is carried out manually. At least 12 of these species were unable to form F2 progeny, and eight were unable to produce progeny when the F1 was backcrossed to one of the parental species. Many factors will influence the success of hybridization under field conditions, including: distance between the parents, synchrony of flowering, method of pollen spread, specific parental genotypes used, direction of the cross and the environmental conditions. Even where there is a possibility of hybridization betweenB. napus and a related species growing in the vicinity of a release, poor vigour and high sterility in the hybrids will generally mean that hybrids and their progeny will not survive in either an agricultural or natural habitat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973586
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  • 39
    Electronic Resource
    Electronic Resource
    Actin microfilament organization during pollen development ofBrassica napus cv. Topas (1994)
    Springer
    Protoplasma 183 (1994), S. 67-76 
    Details
    ISSN: 1615-6102
    Keywords: Actin microfilaments ; Brassica napus ; Cytochalasin D ; Pollen development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The organization of actin microfilaments (MFs) was studied during pollen development ofBrassica napus cv. Topas. Cells were prepared using three techniques and double labelled for fluorescence microscopy with rhodamine-labelled phalloidin for MFs and Hoechst 33258 for DNA. Microfilaments are present at all stages of pollen development with the exception of tricellular pollen just prior to anthesis. Unicellular microspores contain MFs which radiate from the surface of the nuclear envelope into the cytoplasm. During mitosis MFs form a network partially surrounding the mitotic apparatus and extend into the cytoplasm. Both cytoplasmic and phragmoplast-associated MFs are present during cytokinesis. Nuclear associated-, cytoplasmic, and randomly oriented cortical MFs appear in the vegetative cell of the bicellular microspore. Cortical MFs in the vegetative cell organize into parallel MF bundles (MFBs) aligned transverse to the furrows. The MFBs disappear prior to microspore elongation. At anthesis MFs are restricted to the cortical areas subjacent to the furrows of the vegetative cell. The use of cytochalasin D to disrupt MF function resulted in: (1) displacement of the acentric nucleus in the unicellular microspore; (2) displacement of the spindle apparatus in the mitotic cell; (3) symmetrical growth of the bicellular microspore rather than elongation and (4) inhibition of pollen tube germination in the mature pollen grain. This suggests that MFs play an important role in anchoring the nucleus in the unicellular microspore as well as the spindle apparatus during microspore mitosis, in microspore shape determination and in pollen tube germination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276814
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  • 40
    Electronic Resource
    Electronic Resource
    Recombinant viruses as transformation vectors of marine macroalgae (1994)
    Springer
    Journal of applied phycology 6 (1994), S. 247-253 
    Details
    ISSN: 1573-5176
    Keywords: algae ; genes ; recombinant ; transformation ; vectors ; viruses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The large dsDNA viruses that are known to infect eukaryotic algae show promise as genetic vectors for algal biotechnology. The large size (150–330 kbp) of these viral genomes may permit insertion of large sequences of foreign DNA. The viruses infecting filamentous marine brown algae appear to be integrated into the genomes of their hosts, and may provide integration mechanisms that can be used for directing insertion of foreign genes into algal chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02186078
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  • 41
    Electronic Resource
    Electronic Resource
    Maintenance and expression of heterologous genes in chloroplast ofChlamydomonas reinhardtii (1994)
    Springer
    Journal of applied phycology 6 (1994), S. 239-245 
    Details
    ISSN: 1573-5176
    Keywords: Chlamydomonas reinhardtii ; transformation ; chloroplast ; aminoglycoside adenine transferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chloroplast genome ofChlamydomonas reinhardtii has been transformed with a chimeric gene consisting of the chloroplastatpA promoter and the bacterial gene for aminoglycoside adenine transferase (aadA). TheatpA-aadA cassette has been placed within the chloroplast DNAEcoRI restriction enzyme fragment 14, or within the chloroplastBamH1 fragment 10. The chimeric constructs were introduced into the chloroplast by particle bombardment. Integration of the cassette into chloroplast DNA then occurred via homologous recombination of sequences flanking the cassette with their corresponding chloroplast sequences. We demonstrate that the chloroplastatpA promoter inatpA-aadA routinely recombines with its endogenous counterpart, resulting in heteroplasmic chloroplast DNA populations that may persist for many generations. The heterologous gene does not require a 3′ inverted repeat sequence for its expression. TheatpA-aadA gene copy number, which is dictated here by its position in the chloroplast genome, is proportional to the steady state level ofatpA-aadA mRNA. However, neither genomic position, gene copy number, or mRNA level have a significant effect on cellular resistance to spectinomycin, nor activity of theaadA gene productin vitro. These results suggest that, in the case ofaadA, the limiting step for expression of this gene is at the translational or post-translational level. TheatpA-aadA cassette should prove a useful model for future studies on the maintenance and expression of heterologous genes inC. reinhardtii chloroplasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02186077
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  • 42
    Electronic Resource
    Electronic Resource
    A simple technique for producing 13C or 14C-labelled fronds of Lemna gibba and their use in soil incubation investigations (1994)
    Springer
    Plant and soil 160 (1994), S. 185-191 
    Details
    ISSN: 1573-5036
    Keywords: carbon-labelling ; carbon dioxide production ; decomposition ; 14C-glucose ; Lemna ; soil organic matter ; sugars ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The duckweed Lemna gibba required light and a suitable energy source such as sucrose, glucose or fructose, for maximum growth in culture. The requirement for light was relatively unimportant and the plants grew well in a photon flux density of only 52 μmol m-2s-1 PAR. The uptake and incorporation of uniformly labelled 14C-glucose into fronds was related only to the concentration of the sugar. When incubated with soil, labelled L. gibba behaved in a manner similar to that of labelled ryegrass roots which had been produced by a more elaborate technique using a 14CO2 labelled atmosphere. During incubation with soil for 224 days the L. gibba material (specific activity 6133 Bq mg-1 d. wt) lost 64% of its radioactivity as 14CO2 and ryegrass (specific activity 6634 Bq mg-1 d. wt) lost 49%. Alkaline extracted humic and fulvic acids from soil had specific activities for the L. gibba incubation of 3409 and 407 Bq mg-1 solid and for ryegrass roots of 4609 and 546 Bq mg-1 solid respectively. The production of 13C or 14C-labelled L. gibba can be undertaken using only simple equipment producing material the specific radioactivity of which can be controlled by adjusting the activity of the sugar energy source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010144
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  • 43
    Electronic Resource
    Electronic Resource
    Seed colour assessment in Brassica napus using a Near Infrared Reflectance spectrometer adapted for visible light measurements (1994)
    Springer
    Euphytica 76 (1994), S. 45-51 
    Details
    ISSN: 1573-5060
    Keywords: Brassica napus ; light reflectance ; seed colour ; NIR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Improved oil, protein and fibre contents are associated with light seed colour in rapeseed but the lack of reliable and efficient methods to measure seed colour has hindered breeding efforts for this trait. The feasibility of using light reflectance to assess seed colour in Brassica napus was examined using scanning light reflectance spectrophotometry and near infrared reflectance (NIR). Light reflectance by seed samples from 30 doubled haploid (DH) lines segregating for seed colour increased as the wavelength of the illuminating light in the scanning spectrophotometer increased between 550 and 650 nm. The largest reflectance values were measured for the yellow seed samples; the brown seed samples were intermediate and the black seed samples had the lowest reflectance values. The areas under the reflectance curves were used to transform the spectra to single values. Average light reflectance area values for the seed colour classes were significantly different from each other. The DHs and their corresponding light reflectance area values were also used to calibrate a NIR analyzer modified with 670 and 710 nm filters. The best calibration curve used three wavelengths (670, 2190 and 2208 nm) and had a multiple correlation coefficient of 0.987. Light reflectance area values determined with the calibrated NIR analyzer for 30 randomly selected breeding lines could be used to categorize the colour of the seed samples with no discrepancies between the visual and instrument classifications. The results indicate that NIR can be used to assess seed colour in rapeseed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024019
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  • 44
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    Electronic Resource
    A robust protocol for site-directed mutagenesis of the D1 protein inChlamydomonas reinhardtii: A PCR-splicedpsbA gene in a plasmid conferring spectinomycin resistance was introduced into apsbA deletion strain (1994)
    Springer
    Photosynthesis research 42 (1994), S. 121-131 
    Details
    ISSN: 1573-5079
    Keywords: chloroplast ; Photosystem II ; psbA ; site-directed mutagenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper, we describe a protocol to obtain a site-directed mutants in thepsbA gene ofChlamydomonas reinhardtii, which overcomes several drawbacks of previous protocols, and makes it possible to generate a mutant within a month. Since the large size of the gene, and the presence of four large introns has made molecular genetics of thepsbA gene rather unwieldy, we have spliced all of the exons of thepsbA gene by PCR to facilitate genetic manipulation and sequencing of the gene. The resultant construct (plasmid pBA153, with several unique restriction sites introduced at exon boundaries) carried 1.2 and 1.8 kb intact sequences from the 5′- and 3′-flanking regions, respectively. The plasmid was used to transform a D1-deletion mutant and was found to complement the deletion and restore photosynthetic activity. In addition, a bacterialaadA gene conferring spectinomycin resistance (spe r) was inserted downstream of the intron-freepsbA gene, to give construct pBA155. This allowed selection of mutant strains deficient in photosynthesis by using spectinomycin resistance, and eliminated the possibility of selection for revertant strains which is a consequence of having to use photosynthetic activity as a selection pressure. Finally, pBA155 was used to construct pBA157, in which additional restriction sites were inserted to facilitate cassette mutagenesis for generation of mutations in spans thought to be involved in donor-side interactions. AllpsbA deletion strains transformed with intron-freepsbA-aadA constructs encoding the wild-type D1 sequence, and screened on spectinomycin plates for thespe r phenotype, were able to grow photosynthetically, and all showed identical kinetics for electron transfer from primary (QA) to secondary quinone (QB) in Photosystem II, as assayed by the decay of the high fluorescence yield on oxidation of the reduced primary acceptor (QA −).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187123
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  • 45
    Electronic Resource
    Electronic Resource
    Some features about transposition of the maize elementDissociation inNicotiana plumbaginifolia (1994)
    Springer
    Genetica 93 (1994), S. 41-48 
    Details
    ISSN: 1573-6857
    Keywords: Ac/Ds ; transformation ; transgenic plants ; transposon tagging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have recently shown that a plasmid-borneDissociation (Ds) element can excise from extrachromosomal plasmid DNA and integrate into a plant genome in the presence of theActivator (Ac) transposase.Ds andAc-carrying plasmids were used to co-transformNicotiana plumbaginifolia protoplasts. Transgenic plants were regenerated and analyzed. Here we describe further characterization of the system and discuss its efficiency in terms of DNA transformation and transposon tagging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01435238
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  • 46
    Electronic Resource
    Electronic Resource
    Transmission of injected DNA sequences to multiple eggs of Metaseiulus occidentalis and Amblyseius finlandicus (Acari: Phytoseiidae) following maternal microinjection (1994)
    Springer
    Experimental and applied acarology 18 (1994), S. 319-330 
    Details
    ISSN: 1572-9702
    Keywords: Maternal microinjection ; transformation ; genetic improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The persistence of DNA injected into two species of adult female phytoseiids and its transmission to serial eggs deposited by them was assessed by the polymerase chain reaction (PCR). The effect of DNA concentration on persistence and transmission was examined in Metaseiulus occidentalis. M. occidentalis females were microinjected with plasmid DNA at three different concentrations (250, 500, 750 ng μL−1) and allowed to deposit one to five eggs before the females and their last eggs were analyzed. Plasmid DNA was found in 82% of the females assayed and in 70% of all the eggs analyzed (including the fifth eggs produced after microinjection). Transmission of DNA to multiple eggs was also examined in Amblyseius finlandicus. Females of this species are less traumatized by microinjection allowing analysis of transmission over a more extended number of eggs. Females were microinjected and allowed to deposit eggs until their death. DNA from every fifth egg was analyzed by the PCR. PCR products were amplified from 51% of the eggs and from all egg classes except the 30th egg. The persistence and presence of plasmid DNA in both eggs and females suggests that (1) maternal microinjection is a more efficient method for DNA delivery than traditional egg microinjection, (2) it may be possible to isolate transformants from fewer maternally-microinjected females than originally expected, and (3) maternal microinjection could be useful as a DNA delivery system in other phytoseiids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00116313
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  • 47
    Electronic Resource
    Electronic Resource
    Genetics and gibberellin production inGibberella fujikuroi (1994)
    Springer
    Antonie van Leeuwenhoek 65 (1994), S. 217-225 
    Details
    ISSN: 1572-9699
    Keywords: Gibberella fujikuroi ; gibberellins ; mutants ; regulation by nitrogen ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the gibberellin biosynthetic pathway as established in Gibberella are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00871950
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  • 48
    Electronic Resource
    Electronic Resource
    Influence of the triazole growth retardant BAS 111..W on phytohormone levels in senescing intact pods of oilseed rape (1994)
    Springer
    Plant growth regulation 14 (1994), S. 115-118 
    Details
    ISSN: 1573-5087
    Keywords: abscisic acid ; 1-aminocyclopropane-1-carboxylic acid ; BAS 111..W ; Brassica napus ; cytokinins ; oilseed rape ; pod ; senescence ; triazole growth retardant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Foliar treatment of oilseed rape plants (Brassica napus L.ssp. napus cv. Linetta) with the growth retardant BAS 111..W at the 5th leaf stage delayed pod senescence during early maturation. Changes of immunoreactive cytokinin- and abscisic acid (ABA)- like substances and of the ethylene precursor 1-aminocyclo-propane-1-carboxylic acid (ACC) and its malonyl-conjugate (MACC) were determined in intact whole pods. When compared with control plants, higher levels of total chlorophyll correlated with four-fold and three-fold increases of trans-zeatin riboside- and dihydrozeatin riboside-type cytokinins, respectively, in the pods of plants treated with 0.25 mg BAS 111..W per plant. Isopentenyladenosine-type cytokinins and ACC and MACC contents remained virtually unchanged, whereas ABA levels dropped considerably below those of controls (60% reduction). However, when analysed at late pod maturity, BAS 111..W treatment no longer affected the total chlorophyll content, or the levels of cytokinins, ABA, ACC and MACC. We hypothesize that the retardant-induced changes in the hormonal status of the pods, favouring the senescence-delaying cytokinins as opposed to abscisic acid, could contribute to the developmental delay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025211
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  • 49
    Electronic Resource
    Electronic Resource
    Self-incompatibility as a pollination control mechanism for spring oilseed rape, Brassica napus L. (1994)
    Springer
    Euphytica 75 (1994), S. 27-30 
    Details
    ISSN: 1573-5060
    Keywords: Brassica napus ; heterosis ; hybrid breeding ; oilseed rape ; self-incompatibility ; pollination control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Self-incompatibility was shown to be an effective method of pollination control in spring rapeseed (B. napus L. ssp. oleifera (Metzg.)) by comparing the yield of a Westar-Topas syn-1 produced by crossing two SI lines with the yield of the corresponding syn-1 produced by hand pollination. Although the trial showed high-parent heterosis in the syn-1s, there was insufficient replication to determine the level of heterosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024528
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  • 50
    Electronic Resource
    Electronic Resource
    Stability of bacterial leaf spot resistance in peach regenerants under in vitro, greenhouse and field conditions (1994)
    Springer
    Euphytica 76 (1994), S. 101-106 
    Details
    ISSN: 1573-5060
    Keywords: in vitro selection ; Prunus persica ; somaclonal variation ; Xanthomonas campestris pv. pruni ; bacterial leaf spot of peach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Phenotypic stability of bacterial leaf spot resistance in peach (Prunus persica (L.) Batsch) regenerants, either selected at the cellular level for insensitivity to a toxic culture filtrate of Xanthomonas campestris pv. pruni or screened at the whole plant level for resistance to X. campestris pv. pruni, was investigated. A detached-leaf bioassay was used to evaluate the original regenerants again after three years in the greenhouse and also after a two to three year cycle of tissue culture propagation. Peach trees derived through micropropagation from the original regenerants were also evaluated after one to three years growth in the field. Although leaf spot resistance was retained in some regenerants over time in the greenhouse, following in vitro propagation, and under field conditions, resistance was either lost or not expressed in others. Regenerants # 19-1 and #156-6, derived from embryo callus of bacterial spot susceptible ‘Sunhigh’, were significantly more resistant than ‘Sunhigh’. High levels of resistance were exhibited in greenhouse plants and field-grown trees of regenerant #122-1, derived from embryo callus of moderately resistant ‘Redhaven’. This research provides additional evidence that selecting or screening for somaclonal variants with disease resistance is a feasible approach to obtaining peach trees with increased levels of bacterial spot resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024026
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  • 51
    Electronic Resource
    Electronic Resource
    Somaclonal variation for resistance to Verticillium dahliae in potato (Solanum tuberosum L.) plants regenerated from callus (1994)
    Springer
    Euphytica 80 (1994), S. 5-11 
    Details
    ISSN: 1573-5060
    Keywords: disease resistance ; filtrate selection ; Solanum tuberosum (cvs Désirée, Kondor) ; somaclonal variation ; Verticillium dahliae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Plant tissue culture is recognized as an important tool to generate useful genetic variability for crop improvement. Regenerated plants from callus induced from stem explants of Solanum tuberosum cv Désirée were assessed by in vitro selection, for resistance to Verticillium dahliae. This fungus is the causal agent of Verticillium wilt, a serious vascular wilt disease both in crops and wild species. The rate of in vitro multiplication by single node cuttings was used as a parameter of screening in two selection cycles with different concentrations of V. dahliae filtrate. One resistant clone was selected and then evaluated by inoculation in the growth chamber. Induced damage, and morphological traits (dry weight, leaf area and tuber production) were estimated. The selected clone was comparable to the resistant control, cv Kondor. The results suggest that genetic variation induced in tissue culture cound be utilized to generate disease resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039292
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  • 52
    Electronic Resource
    Electronic Resource
    Stably transformed cell lines from protoplasts of maize endosperm suspension cultures (1994)
    Springer
    Plant cell, tissue and organ culture 37 (1994), S. 39-46 
    Details
    ISSN: 1573-5044
    Keywords: endosperm cell culture ; maize ; protoplast ; transformation ; zeins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protoplasts were isolated from Zea mays (L.) A69Y endosperm suspension cultures and transformed by polyethylene glycol mediated DNA uptake with chimaeric gene constructs containing β-glucuronidase (GUS) or neomycin phosphotransferase II (NPTII); GUS-expressing and Kanamycin-resistant cultures were recovered. The transformed cells showed integration of the introduced foreign genes into genomic DNA and maintained their ability to synthesize endosperm-specific reserve proteins (zeins). No deletion or rearrangement of zein genes were observed in transformed cultures. Stable transformation of cultured maize endosperm cells may therefore represent a new methodological approach for the study of the transcriptional regulation of endosperm-expressed genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048115
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  • 53
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    Electronic Resource
    Efficient plant regeneration through somatic embryogenesis from callus induced on mature rice embryos (Oryza sativa L.) (1994)
    Springer
    Plant cell, tissue and organ culture 36 (1994), S. 259-264 
    Details
    ISSN: 1573-5044
    Keywords: monocotyledons ; Oryza sativa L. ; plant regeneration ; rice ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To obtain a reproducible efficient procedure for regeneration of rice plants through somatic embryogenesis from callus four published methods of callus induction and regeneration were compared. Callus was initiated from mature embryos of the Japonica cultivar Taipei 309 of rice (Oryza sativa L.). The number, mass and morphology of the callus formed on the scutellum were dependent on the medium used. A limited humidity and an optimal aeration of the culture vessels enhanced the frequency of embryogenesis and plant regeneration. A method described by Poonsapaya et al. (1989) was found to be the most efficient and was slightly modified. As a result 98% of the T309 embryos formed callus, of which 63% regenerated into plants. Each callus yielded an average of 6 plants. Plant morphology, fertility and seed set of the regenerants were found to be normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00037729
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  • 54
    Electronic Resource
    Electronic Resource
    Factors that effect leaf regeneration efficiency in apple, and effect of antibiotics in morphogenesis (1994)
    Springer
    Plant cell, tissue and organ culture 37 (1994), S. 257-269 
    Details
    ISSN: 1573-5044
    Keywords: adventitious shoots ; Malus x domestica Borkh. ; tissue culture ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several factors that affect the frequency of organogenesis in apple leaf explants were examined for the scion cultivars ‘Empire’, ‘Freedom’, ‘Golden Delicious’, ‘Liberty’, ‘McIntosh’, and ‘Mutsu’ and for the rootstocks Malling 7A and Malling 26. The main factors affecting morphogenesis were BA concentration, basal medium, leaf explant origin and maturity, explant orientation, and photosynthetic photon flux. Depending on the genotype, optimal regeneration was obtained using either 22.2 or 31.1 μM BA and the N6 basal medium, with the exception of ‘Golden Delicious’ which regenerated better on MS medium. After 6 weeks, the average number of shoots per segment varied from 5 to 16, and the percentage of regeneration between 70 and 100%, depending on the genotype tested and the maturity of the explant. Regeneration capacity increased dramatically from the tip towards the base of the leaf, and was higher from the middle to the proximal end. Cefotaxime and carbenicillin, two antibiotics commonly used during transformation studies to eliminate Agrobacterium tumefaciens from plant tissue, were tested to determine their effect on morphogenesis. Cefotaxime at a dose of 250 mg 1-1 enhanced regeneration and shoot development, whereas carbenicillin at a dose of 500 mg l-1 induced abundant callus formation and inhibited regeneration. Kanamycin, a widely used selection agent for plant transformation, strongly inhibited regeneration even at very low doses. Schemes for selection and recovery of transgenic apple plants when kanamycin is used as the selection agent are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042339
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  • 55
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    Electronic Resource
    Efficient production of doubled haploid Brassica napus plants by colchicine treatment of microspores (1994)
    Springer
    Euphytica 75 (1994), S. 95-104 
    Details
    ISSN: 1573-5060
    Keywords: Brassica napus ; microspore culture ; colchicine treatment ; chromosome doubling ; DH-breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of colchicine on isolated microspore cultures of Brassica napus was evaluated in order to combine a positive effect of colchicine on the induction of embryogenesis with the possibility to induce chromosome doubling at an early developmental stage, thus avoiding the production of haploid or chimeric plants. Colchicine was added to the culture medium immediately after isolation of B. napus microspores. The cultures were incubated from 6 to 72 h with various concentrations of colchicine. Samples were taken from the regenerating embryoids after 6 weeks for ploidy determination by flow-cytometry. The highest diploidization rate was obtained after a 24 h treatment of microspores with 50 mg/l colchicine, leading to 80–90% diploid embroids. A concentration of 100 mg/l colchicine applied for the same duration resulted in a lower diploidization rate (76–80%). Treatment durations of 6 h were not long enough to induce a high rate of diploidization, whereas the application of 10 mg/l for 72 h was also very effective. A sample of the plants regenerated from the colchicine treated microspores was transferred to the greenhouse. The plants looked similar to normal diploid rapeseed plants and showed reasonable pod and seed set. Thus, an additional generation for seed increase in the greenhouse is rendered unnecessary. The advantage of applying a minimum volume of colchicine under controlled in vitro conditions means a considerable saving of time and labour in DH-breeding programs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024536
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  • 56
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    Electronic Resource
    Genetic control of frost tolerance in wheat (Triticum aestivum L.) (1994)
    Springer
    Euphytica 77 (1994), S. 277-282 
    Details
    ISSN: 1573-5060
    Keywords: Wheat ; frost tolerance ; diallel cross ; monosomics ; Triticum aestivum ; chromosome substitutions ; wild species ; somaclonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The frost tolerance of winter wheat is one component of winter hardiness. If seedlings are frost resistant, it means that they can survive the frost effect without any considerable damage. To study the genetic control of frost tolerance, an artificial freezing test was used. Frost tolerance is controlled by an additive-dominance system. The results of diallel analyses indicate the importance of both additive and non-additive gene action in the inheritance of this character. The dominant genes act in the direction of lower frost tolerance and the recessive genes in the direction of a higher level of frost tolerance. The results of monosomic and substitution analyses show that at least 10 of the 21 pairs of chromosomes are involved in the control of frost tolerance and winter hardiness. Chromosomes 5A and 5D have been implicated most frequently. The geneFr1 (Frost 1) was located on the long arm of chromosome 5A. Crosses between cultivars, chromosome manipulation and the induction of somaclonal variation may be suitable methods for broadening the gene pool for frost tolerance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262642
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    Electronic Resource
    Inheritance of male sterility mutations induced in haploid sorghum tissue culture (1994)
    Springer
    Euphytica 80 (1994), S. 111-118 
    Details
    ISSN: 1573-5060
    Keywords: somaclonal variation ; cytoplasmic inheritance ; cytoplasmic male sterility ; fertility restorer genes ; Sorghum bicolor (L.) Moench ; sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A high frequency of male sterile mutants regeneration was shown in callus cultures derived from leaves and panicles of haploid sorghum (Msc1, A1 cytoplasm) and a spontaneous autodiploid obtained from this haploid. The cultures derived from the embryos of this autodiploid yielded significantly fewer mutants. Absolutely or partially male sterile mutants appeared among the regenerants or in the progeny of fertile regenerants. In the self-fertilized progenies of partially male sterile mutants and in the hybrids of sterile mutants with autodiploid line (i.e. under one and the same nuclear genome) male sterility mutations were inherited as cytoplasmic. Non-Mendelian segregation of sterile, partially male sterile and fertile plants was observed in these progenies. Partially male sterile plants were characterized by somatic segregation of male sterility genetic factors. In test-crosses with some CMS A1 fertility restorers, mutations were manifested as nuclear recessive while with others as nuclear dominant. These differences are supposed to be the result of interaction of fertility restorer genes of these testers with the novel cytoplasm. Male sterility mutations accompanied with female sterility were inherited as nuclear recessives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039305
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    Micropropagation of thirteen Malus cultivars and rootstocks, and effect of antibiotics on proliferation (1994)
    Springer
    Plant growth regulation 15 (1994), S. 55-67 
    Details
    ISSN: 1573-5087
    Keywords: apple (Malus × domestica Borkh.) ; selection ; tissue culture ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several factors that affect in vitro establishment, proliferation, and rooting of thirteen Malus cultivars and rootstocks were studied. Apple shoot tips (1.5±0.5 cm in length) were established using ascorbic and citric acids as antioxidants. Four proliferation media containing 1.0 mg 1−1 BA and different concentrations of IBA and GA3 were tested. Proliferation rates varied depending on the genotype and medium used. The highest proliferation rate was obtained for a rootstock that produced 11.6±2.5 shoots (1.5±0.8 cm in length) per tube per month. Rooting was induced with IBA for all the genotypes tested. The optimal IBA concentration was cultivar dependent (between 0.1 and 1.0 mg 1−1 IBA), and lower concentrations were necessary to induce rooting in liquid rather than in solid medium. The effects on shoot-tip proliferation of cefotaxime, carbenicillin and kanamycin, three antibiotics commonly used for transformation studies, were also evaluated. Cefotaxime at 200 mg 1−1 stimulated shoot growth and development, but at 500 mg 1−1 caused abnormal shoot morphology. Carbenicillin at 500 mg 1−1, alone or in combination with cefotaxime at 200 mg 1−1, inhibited proliferation and caused excessive enlargement of the basal leaves, inducing callus formation and release of phenolic compounds in the medium. Kanamycin at 50 mg 1−1 was phytotoxic and caused shoot chlorosis and necrosis. Consideration of the toxicity of these antibiotics is critical when designing transformation schemes for selection and recovery of transgenic apple plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024677
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    Electronic Resource
    In what situations isin vitro culture appropriate to plant conservations? (1994)
    Springer
    Biodiversity and conservation 3 (1994), S. 176-183 
    Details
    ISSN: 1572-9710
    Keywords: conservation ; cryopreservation ; in vitro culture ; micropropagation ; somaclonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variousin vitro techniques are available for plant propagation, including seed germination, micropropagation, meristem culture and callus culture. The role of these techniques in the conservation of endangered plants is discussed, using examples drawn from the work of the Micropropagation Unit at Kew.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02291887
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    Electronic Resource
    Transgenic plants: performance, release and containment (1994)
    Springer
    World journal of microbiology and biotechnology 10 (1994), S. 139-144 
    Details
    ISSN: 1573-0972
    Keywords: Gene flow ; insertion mutagenesis ; marker genes ; pleiotropy ; somaclonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This review focuses on transgenic plants, from the initial stages of the genetic modification process in the laboratory to their release stage in the field and indicates possible areas of concern and strategies for dealing with them. The classes of marker genes and issues about their safety, the gene flow and strategies that are used to isolate transgenic plants genetically are specifically examined. In addition, an assessment is provided of the phenomena which affect the performance of transgenic plants, such as gene disruption, the pleiotropic effect on plant phenotype and genetic variation. Finally, strategies are suggested for preventing unexpected consequences of transgenic plant production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00360874
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    Different tumorigenicity of cell clones derived from stromal fibroblasts of human colon cancer xenografts (1994)
    Springer
    Bulletin of experimental biology and medicine 118 (1994), S. 879-882 
    Details
    ISSN: 1573-8221
    Keywords: fibroblasts ; xenografts ; thymus-free animals ; transformation ; immortalization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The tumorigenicity of cell clones derived from fibroblast lines isolated from colon cancer xenografts is studied in thymus-free animals. During cloning of the cell line obtained from the 3rd passage of the xenograft about 20% of the clones proved to be nontumorigenic, whereas such cells were not found in the line obtained from the 89th passage. Cytogenetic analysis of nontumorigenic clones revealed monosomy for the 13th chromosome with no alterations in the other chromosome pairs. Hybridization for the presence of Alu sequences was negative.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02444455
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  • 62
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    A method for quantifying the gene flow that results from a single bumblebee visit using transgenic oilseed rape,Brassica napus L. cv. Westar (1994)
    Springer
    Transgenic research 3 (1994), S. 134-137 
    Details
    ISSN: 1573-9368
    Keywords: gene flow ; pollination ; bumblebees ; oilseed rape ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetically modified plants containing selectable markers offer a unique opportunity for pollination biologists to investigate some of the major, but intractable questions about paternity distributions and their causes. Here, a method is reported that uses transgenic plants to enable the quantification of the outcrossed fertilizations that result from a single pollinator visit. Gene flow mediated by worker bumblebees (Bombus terrestris) was studied among plants of oilseed rape (Brassica napus L. cv. Westar) where transgenic paternity in seeds of a non-transgenic plant was manifested as herbicide resistance. Overall, 91% of the resistant seeds resulted from the first four flowers that were visited after the bumblebee left the transgenic plant, and none was found beyond the 14th successively visited flower. The possibilities for developing the method to address various questions in pollination biology are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01974092
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  • 63
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    Electronic Resource
    Selectable marker replacement in Saccharomyces cerevisiae (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 141-149 
    Details
    ISSN: 0749-503X
    Keywords: Saccharomyces cerevisiae ; selectable marker ; transformation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Selectable markers integrated by the ‘gamma’ deletion method (Sikorski and Hieter, 1989) can be efficiently replaced in vivo with other markers by transformation with homologous plasmids. Transformation frequencies in experiments designed to replace original selectable markers with an alternate marker were high and molecular analysis confirmed that all transformants that exhibited the expected phenotypes (loss of the original prototrophy and gain of the alternate prototrophy) resulted from homologous recombination between plasmid sequences at the target locus. This technique involves no plasmid construction and greatly facilitates the generation of yeast cells containing multiple gene disruptions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320100202
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    Biomethylation and biotransformation of arsenic in a freshwater food chain: Green alga (chlorella vulgaris)→shrimp (neocaridina denticulata)→killifish (oryzias iatipes) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 8 (1994), S. 325-333 
    Details
    ISSN: 0268-2605
    Keywords: Arsenic ; methylation ; transformation ; freshwater food chain ; green alga ; shrimp ; killifish ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tolerance, bioaccumulation, biotransformation and excretion of arsenic compounds by the fresh-water shrimp (Neocaridina denticulata) and the killifish (Oryzias latipes) (collected from the natural environment) were investigated. Tolerances (LC50) of the shrimp against disodium arsenate [abbreviated as As(V)], methylarsonic acid (MAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB) were 1.5, 10, 40, and 150μg As ml-1, respectively.N. denticulata accumulated arsenic from an aqueous phase containing 1 μg As ml-1 of As(V), 10 μg As ml-1 of MAA, 30 μg As ml-1 of DMAA or 150 μg As ml-1 of AB, and biotransformed and excreted part of these species. Both methylation and demethylation of the arsenicals were observed in vivo. When living N. denticulata accumulating arsenic was transferred into an arsenic-free medium, a part of the accumulated arsenic was excreted. The concentration of methylated arsenicals relative to total arsenic was higher in the excrement than in the organism.Total arsenic accumulation in each species via food in the food chainGreen algae (Chlorella vulgaris)→ shrimp (N. denticulata)→ killifish (O. latipes)decreased by one order of magnitude or more, and the concentration of methylated arsenic relative to total arsenic accumulated increased successively with elevation in the trophic level. Only trace amounts of monomethylarsenic species were detected in the shrimp and fish tested. Dimethylarsenic species in alga and shrimp, and trimethylarsenic species in killifish, were the predominant methylated arsenic species, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590080407
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    Stable transformation of the food yam Dioscorea alata L. by particle bombardment (1993)
    Springer
    Plant cell reports 12 (1993), S. 468-473 
    Details
    ISSN: 1432-203X
    Keywords: Dioscorea alata ; GUS ; transformation ; particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A biolistic particle gun was used to deliver genetic material into intact yam cells. Cultured suspension cells of D. alata were bombarded with microprojectiles coated with pBI221.2 DNA and histochemical assays were carried out to show transient GUS expression in bombarded cells. Stably transformed D. alata cells were recovered from cultured cells after bombardment with microprojectiles coated with pRT99gus harbouring both the nptII and uidA genes. Bombarded cells were selected on a medium containing geneticin (G418). Two months after bombardment, calli resistant to G418 were assayed for GUS expression. There was a 100% correlation between resistance to G418 and GUS expression. From these calli, four cell lines were established and GUS activity in each line was determined fluorometrically. The use of a specific GUS inhibitor showed that the GUS activity was due to the introduced uidA gene rather than to any intrinsic GUS-like activity originating from the plant. Incorporation of the introduced DNA into the plant genomic DNA was confirmed by Southern analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234714
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    Enhanced transformation of tomato co-cultivated with Agrobacterium tumefaciens C58C1Rifr::pGSFR1161 in the presence of acetosyringone (1993)
    Springer
    Plant cell reports 12 (1993), S. 422-425 
    Details
    ISSN: 1432-203X
    Keywords: Acetosyringone ; Agrobacterium tumefaciens ; tomato ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Explants of tomato (Lycopersicon esculentum Mill cv. Ailsa Craig) were co-cultivated with Agrobacterium tumefaciens C58C1Rifr::pGSFR1161 in the presence of 20 (μM acetosyringone). Transformed root clones were selected on kanamycin medium and the presence of the nptII gene in the plant DNA confirmed by the polymerase chain reaction. Root clones derived from acetosyringone treatment grew more vigorously in the presence of kanamycin and synthesized a greater amount of NPT-II enzyme. The conclusion is that acetosyringone treatment enhances the transformation process, possibly by stimulating multiple insertions of the T-DNA into the host genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234705
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    A model for studying pollination and pod development in Brassica napus: the culture of isolated flowers (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 52-56 
    Details
    ISSN: 1432-2145
    Keywords: In vitro culture ; Brassica napus ; Pollination ; Pod ; Seed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A technique for cultivating isolated flowers of Brassica napus has been developed. Flowers were harvested at anthesis, the surface of their peduncles was then sterilized and they were cultivated in a hormonefree medium. We used an MS medium supplemented with 3% sucrose as a source of organic carbon. From our experiments, it was concluded that no exogenous growth regulator is required to ensure normal growth and development in vitro. The flowers, and thereafter the pods, can be kept in culture until seed maturity. After 30 days, seed development resulted in three types of seeds: (1) normal, (2) milky and (3) aborted. The results show that the number of seeds per pod was not dependent on the order of flowers on the raceme (except the first 10 flowers and flowers above row 50). Our study supports the validity of this model as an easy tool for studying pollination and early seed development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227583
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    Transformation of maize (Zea mays L.) protoplasts and regeneration of haploid transgenic plants (1993)
    Springer
    Plant cell reports 13 (1993), S. 63-68 
    Details
    ISSN: 1432-203X
    Keywords: Zea mays L ; microspore-derived cultures ; haploid ; regeneration ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic haploid maize (Zea mays L.) plants were obtained from protoplasts isolated from microspore-derived cell suspension cultures. Protoplasts were electroporated in the presence of plasmid DNA containing the gus A and npt II genes encoding ß-glucuronidase (GUS) and neomycin phosphotransferase II (NPT II), respectively. Transformed calli were selected and continuously maintained on kanamycin containing medium. Stable transformation was confirmed by enzyme assays and DNA. analysis. Stably transformed tissue was transferred to regeneration medium and several plants were obtained. Most plants showed NPT II activity, and some also showed GUS activity. Chromosome examinations performed on representative plants showed that they were haploid. As expected, these plants were infertile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235291
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    Analysis of genetic stability of plants regenerated from suspension cultures and protoplasts of meadow fescue (Festuca pratensis Huds.) (1993)
    Springer
    Plant cell reports 12 (1993), S. 101-106 
    Details
    ISSN: 1432-203X
    Keywords: Festuca pratensis ; suspension cultures ; protoplasts ; plant regeneration ; somaclonal variation ; genetic fidelity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cytological and molecular analysis was performed to assess the genetic uniformity and true-to-type character of plants regenerated from 20 week-old embryogenic suspension cultures of meadow fescue (Festuca pratensis Huds.), and compared to protoplastderived plants obtained from the same cell suspension. Cytological variation was not observed in a representative sample of plants regenerated directly from the embryogenic suspensions and from protoplasts isolated therefrom. Similarly, no restriction fragment length polymorphisms (RFLPs) were detected in the mitochondrial, plastid and nuclear genomes in the plants analyzed. Randomly amplified polymorphic DNA markers (RAPDs) have been used to characterise molecularly a set of mature meadow fescue plants regenerated from these in vitro cultures. RAPD markers using 18 different short oligonucleotide primers of arbitrary nucleotide sequence in combination with polymerase chain reaction (PCR) allowed the detection of pre-existing polymorphisms in the donor genotypes, but failed to reveal newly generated variation in the protoplast-derived plants compared to their equivalent suspensionculture regenerated materials. The genetic stability of meadow fescue plants regenerated from suspension cultures and protoplasts isolated therefrom and its implications on gene transfer technology for this species are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241943
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    Semi-constitutive expression of an Arabidopsis thaliana α-tubulin gene (1993)
    Springer
    Plant molecular biology 21 (1993), S. 937-942 
    Details
    ISSN: 1573-5028
    Keywords: α-tubulin ; Arabidopsis ; β-glucuronidase ; gene expression ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Arabidopsis tissues, the pool of tubulin protein is provided by the expression of multiple α-tubulin and β-tubulin genes. Previous evidence suggested that the TUA2 α-tubulin gene was expressed in all organs of mature plants. We now report a more detailed analysis of TUA2 expression during plant development. Chimeric genes containing TUA2 5′-flanking DNA fused to the β-glucuronidase (GUS) coding region were used to create transgenic Arabidopsis plants. Second-generation progeny of regenerated plants were analyzed by histochemical assay to localize GUS expression. GUS activity was seen throughout plant development and in nearly all tissues. The blue product of GUS activity accumulated to the highest levels in tissues with actively dividing and elongating cells. GUS activity was not detected in a few plant tissues, suggesting that, though widely expressed, the TUA2 promoter is not constitutively active.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027126
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    Treatment of Agrobacterium or leaf disks with 5-azacytidine increases transgene expression in tobacco (1993)
    Springer
    Plant molecular biology 21 (1993), S. 429-435 
    Details
    ISSN: 1573-5028
    Keywords: azacytidine ; DNA methylation ; gene expression ; inactivation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have studied the effect of the demethylating agent azacytidine (azaC) on expression of a β-glucuronidase (GUS) gene transferred to tobacco leaf disks by Agrobacterium-mediated transformation. In a system where no selection was performed, where shoot formation was partially repressed, and where Agrobacterium does not express the GUS gene, we were able to follow the early events of transient and stable expression. Two days after inoculation, 8% of the cells expressed GUS but this proportion rapidly decreased to near zero in the following week. Treatment of leaf disks with azaC just after transformation retarded this inactivation to some extent, while treatment of Agrobacterium prior to transformation increased the frequency of transient expression. Three weeks after inoculation the number of GUS-expressing cells increased 4- to 6-fold in the leaf disks treated with azaC and in the leaf disks transformed with azaC-treated bacteria, while the control remained low. These data suggest that DNA methylation is involved in transgene inactivation and that a large number of silent but potentially active transgenes become integrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028801
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    Activity of a chimeric promoter with the doubled CaMV 35S enhancer element in protoplast-derived cells and transgenic plants in maize (1993)
    Springer
    Plant molecular biology 21 (1993), S. 415-428 
    Details
    ISSN: 1573-5028
    Keywords: Zea mays L. ; protoplast ; DNA uptake ; transformation ; β-glucuronidase ; promoter ; α-amylase gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A reproducible and efficient transformation system has been developed for maize that is based on direct DNA uptake into embryogenic protoplasts and regeneration of fertile plants from protoplast-derived transgenic callus tissues. Plasmid DNA, containing the β-glucuronidase (GUS) gene, under the control of the doubled enhancer element (the −208 to −46 bp upstream fragment) from CaMV 35S promoter, linked to the truncated (up to −389 bp from ATG) promoter of wheat, α-amylase gene was introduced into protoplasts from suspension culture of HE/89 genotype. The constructed transformation vectors carried either the neomycin phosphotransferase (NPTII) or phosphinothricin acetyltransferase (PAT) gene as selective marker. The applied DNA uptake protocol has resulted at least in 10–20 resistant calli, or GUS-expressing colonies after treatment of 106 protoplasts. Vital GUS staining of microcalli has made possible the shoot regeneration from the GUS-stained tissues. 80–90% of kanamycin or PPT resistant calli showed GUS activity, and transgenic plants were regenerated from more than 140 clones. Both Southern hybridization and PCR analysis showed the presence of introduced foreign genes in the genomic DNA of the transformants. The chimeric promoter, composed of a tissue specific monocot promoter, and the viral enhancer element specified similar expression pattern in maize plants, as it was determined by the full CaMV 35S promoter in dicot and other monocot plants. The highest GUS specific activity was found in older leaves with progressively less activity in young leaves, stem and root. Histochemical localization of GUS revealed promoter function in leaf epidermis, mesophyll and vascular bundles, in the cortex and vascular cylinder of the root. In roots, the meristematic tip region and vascular tissues stained intensively. Selected transformants were grown up to maturity, and second-generation seedlings with segregation for GUS activity were obtained after outcrossing. The GUS-expressing segregants carried also the NPTII gene as shown by Southern hybridization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028800
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    Characterization of a Brassica napus myrosinase pseudogene: myrosinases are members of the BGA family of β-glycosidases (1993)
    Springer
    Plant molecular biology 21 (1993), S. 463-474 
    Details
    ISSN: 1573-5028
    Keywords: active site ; β-glycosidases ; Brassica napus ; glucosinolates ; myrosinase ; thioglucoside ; glucohydrolase (EC 3.2.3.1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Myrosinase isoenzymes are known to be encoded by two different families of genes denoted MA and MB. Nucleotide sequence analysis of a Brassica napus genomic clone containing a gene for myrosinase revealed it to be a pseudogene of the MA family. The gene spans more than 5 kb and contains at least 12 exons. The exon sequence of the gene is highly similar to myrosinase cDNA sequences. However, the gene displays three potential or actual pseudogene characters. Southern blot analysis using probes from the 3′ portions of the genomic and B. napus MA and MB cDNA clones showed that MA type myrosinases are encoded by approximately 4 genes, while MB type myrosinases are encoded by more than 10 genes in B. napus. Northern blots with mRNA from seeds and young leaves probed with the MA-and MB-specific probes showed that the MA and MB myrosinase gene families are differentially expressed. Myrosinases are highly similar to proteins of a β-glycosidase enzyme family comprising both β-glycosidases and phospho-β-glycosidases of as diverged species as archaebacteria, bacteria, mammals and plants. By homology to these β-glycosidases, putative active site residues in myrosinase are discussed on the basis of the similarity between β-glycosidases and cellulases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028804
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    Transient and stable expression ofgusA fusions with rice genes in rice, barley and perennial ryegrass (1993)
    Springer
    Plant molecular biology 22 (1993), S. 1101-1127 
    Details
    ISSN: 1573-5028
    Keywords: transformation ; promoters ; introns ; gene expression ; Oryza sativa ; Hordeum vulgare ; Lolium perenne
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcriptional and translational fusions were made between the reading frame coding for β-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. TheGOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused togusA. ThegusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to theGOS2 constructs was found in stably transformed rice callus. ThegusA fusions with the mannopine synthase promoters 1′ and 2′ of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of theGOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028980
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    Transient and stable expression of gusA fusions with rice genes in rice, barley and perennial ryegrass (1993)
    Springer
    Plant molecular biology 23 (1993), S. 643-669 
    Details
    ISSN: 1573-5028
    Keywords: transformation ; promoters ; introns ; gene expression ; Oryza sativa ; Hordeum vulgare ; Lolium perenne
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcriptional and translational fusions were made between the reading frame coding for β-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. The GOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused to gusA. The gusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to the GOS2 constructs was found in stably transformed rice callus. The gusA fusions with the mannopine synthase promoters 1′ and 2′ of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of the GOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021522
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    Use of bar as a selectable marker gene and for the production of herbicide-resistant rice plants from protoplasts (1993)
    Springer
    Plant molecular biology 21 (1993), S. 871-884 
    Details
    ISSN: 1573-5028
    Keywords: bar ; herbicide resistance ; phosphinothricin acetyltransferase ; rice ; selectable marker ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have used the bar gene in combination with the herbicide Basta to select transformed rice (Oryza sativa L. cv. Radon) protoplasts for the production of herbicide-resistant rice plants. Protoplasts, obtained from regenerable suspension cultures established from immature embryo callus, were transformed using PEG-mediated DNA uptake. Transformed calli could be selected 2–4 weeks after placing the protoplast-derived calli on medium containing the selective agent, phosphinothricin (PPT), the active component of Basta. Calli resistant to PPT were capable of regenerating plants. Phosphinothricin acetyltransferase (PAT) assays confirmed the expression of the bar gene in plants obtained from PPT-resistant calli. The only exceptions were two plants obtained from the same callus that had multiple copies of the bar gene integrated into their genomes. The transgenic status of the plants was varified by Southern blot analysis. In our system, where the transformation was done via the protoplast method, there were very few escapes. The efficiency of co-transformation with a reporter gene gusA, was 30%. The To plants of Radon were self-fertile. Both the bar and gusA genes were transmitted to progeny as confirmed by Southern analysis. Both genes were expressed in T1 and T2 progenies. Enzyme analyses on T1 progeny plants also showed a gene dose response reflecting their homozygous and heterozygous status. The leaves of To plants and that of the progeny having the bar gene were resistant to application of Basta. Thus, the bar gene has proven to be a useful selectable and screenable marker for the transformation of rice plants and for the production of herbicide-resistant plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027118
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    Construction of a Synechocystic PCC6803 mutant suitable for the study of variant hexadecameric ribulose bisphosphate carboxylase/oxygenase enzymes (1993)
    Springer
    Plant molecular biology 23 (1993), S. 465-476 
    Details
    ISSN: 1573-5028
    Keywords: carboxysomes ; cyanobacteria ; rbc genes ; Rubisco ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cyanobacterium Synechocystis PCC6803 was chosen as a target organism for construction of a suitable photosynthetic host to enable selection of variant plant-like ribulose bisphosphate carboxylase/oxygenase (Rubisco) enzymes. The DNA region containing the operon encoding Rubisco (rbc) was cloned, sequenced and used for the construction of a transformation vector bearing flanking sequences to the rbc genes. This vector was utilized for the construction of a cyanobacterial rbc null mutant in which the entire sequence comprising both rbc genes, was replaced by the Rhodospirillum rubrum rbcL gene linked to a chloramphenicol resistance gene. Chloramphenicol-resistant colonies, Syn6803†rbc, were detected within 8 days when grown under 5% CO2 in air. These transformants were unable to grow in air (0.03% CO2). Analysis of their genome and Rubisco protein confirmed the site of the mutation at the rbc locus, and indicated that the mutation had segregated throughout all of the chromosome copies, consequently producing only the bacterial type of the enzyme. In addition, no carboxysome structures could be detected in the new mutant. Successful restoration of the wild-type rbc locus, using vectors bearing the rbc operon flanked by additional sequences at both termini, could only be achieved upon incubating the transformed cells under 5% CO2 in air prior to their transferring to air. The yield of restored transformants was proportionally related to the length of those sequences flanking the rbc operon which participate in the homologous recombination. The Syn6803Δrbc mutant is amenable for the introduction of in vitro mutagenized rbc genes into the rbc locus, aiming at the genetic modification of the hexadecameric type Rubisco.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019295
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  • 78
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    Deletion analysis of a 2S seed storage protein promoter of Brassica napus in transgenic tobacco (1993)
    Springer
    Plant molecular biology 23 (1993), S. 671-683 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; deletion analysis ; napin ; promoter ; seed ; storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The promoter and upstream region of the Brassica napus 2S storage protein napA gene were studied to identify cis-acting sequences involved in developmental seed-specific expression. Fragments generated by successive deletions of the 5′ control region of the napA gene were fused to the reporter gene β-glucuronidase (GUS). These constructs were used to transform tobacco leaf discs. Analyses of GUS activities in mature seeds from the transformed plants indicated that there were both negatively and positively acting sequences in the napin gene promoter. Deletion of sequences between −1101 and −309 resulted in increased GUS activity. In contrast, deletion of sequences between −309 and −211 decreased the expression. The minimum sequence required for seed-specific expression was a 196 bp fragment between −152 and +44. Further 5′ deletion of the fragment to −126 abolished this activity. Sequence comparison showed that a G box-like sequence and two sequence motifs conserved between 2S storage protein genes are located between −148 to −120. Histochemical and fluorometric analysis of tobacco seeds showed that the spatial and developmental expression pattern was retained in the deletion fragments down to −152. However, the expression in tobacco seeds differed from the spatial and temporal expression in B. napus. In tobacco, the napA promoter directed GUS activity early in the endosperm before any visible activity could be seen in the heart-shaped embryo. Later, during the transition from heart to torpedo stages, the main expression of GUS was localized to the embryo. No significant GUS activity was found in either root or leaf.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021523
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  • 79
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    Isolation and characterization of a polygalacturonase gene highly expressed in Brassica napus pollen (1993)
    Springer
    Plant molecular biology 23 (1993), S. 1273-1278 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; pollen ; polygalacturonase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone, Sta 44-4, corresponding to a mRNA highly expressed in Brassica napus cv. Westar stamens, was isolated by differential screening and characterized. Northern blot and in situ analyses demonstrated that Sta 44-4 is synthesized in pollen beginning at the late uninucleate stage and reaches a maximum in trinucleate microspores. Sta 44-4 displayed significant sequence similarity to known pollen polygalacturonase genes. The B. napus pollen polygalacturonase gene was shown to be part of a small gene family and to display some polymorphism among different cultivars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042360
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  • 80
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    Cruciferin gene families are expressed coordinately but with tissue-specific differences during Brassica napus seed development (1993)
    Springer
    Plant molecular biology 23 (1993), S. 1165-1176 
    Details
    ISSN: 1573-5028
    Keywords: cruciferin ; 12S globulin ; Brassica napus ; gene families ; transcription ; in situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major storage protein in seeds of Brassica napus, the 12S globulin cruciferin, is composed of three different groups of subunits; cru1, cru2/3 and cru4. By using gene family-specific probes, we have investigated the accumulation, rate of synthesis and spatial distribution of transcripts corresponding to the different groups of cruciferin subunits in developing seeds. Cruciferin transcripts derived from different gene families accumulate coordinately to comparable amounts during seed development. The corresponding gene families are, however, transcribed at different rates. Investigation of the spatial distribution of transcripts corresponding to each group of cruciferin subunits in the developing seed by in situ hybridization, revealed that mRNAs of all three types accumulate in both axis and cotyledons. Transcripts derived from cru1 and cru4 gene families show a similar cell specificity and accumulate in a similar spatial manner during seed development. In contrast, mRNAs corresponding to the cru2/3 gene family are expressed with a partly different cell specificity and show a slightly different pattern of accumulation in the axis and cotyledons, with a delayed accumulation in epidermal cells. In the cotyledons, the initial accumulation of this type of cruciferin mRNAs is also distinguished from the two other types. The differences in cell specificity are seen in the root cap and in provascular cells, where mRNAs belonging to the cru2/3 family are absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042350
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  • 81
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    Localization of light-inducible and tissue-specific regions of the spinach ribulose bisphosphate carboxylase/oxygenase (rubisco) activase promoter in transgenic tobacco plants (1993)
    Springer
    Plant molecular biology 23 (1993), S. 1129-1138 
    Details
    ISSN: 1573-5028
    Keywords: cis elements ; light regulation ; Rca promoter ; rubisco activase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Deletions in the spinach rubisco activase (Rca) promoter in transgenic tobacco were analyzed to define the regions necessary for conferring light-inducible and tissue-specific expression. Transgenic plants were constructed with Bal 31 deletions of the Rca promoter fused to the coding region of the bacterial reporter gene β-glucuronidase (GUS). Analysis of the Rca deletion mutants localized the region conferring normal expression downstream from −294 relative to the Rca transcription start site. A second set of transgenic plants containing the cauliflower mosaic virus (CaMV) 35S enhancer fused to the 3′ end of the Rca/GUS constructs demonstrated the presence of a light-responsive element between −150 and −78 active in leaves. Regions 10 bp long within the light-responsive region, which included putative G box and GT elements, were removed by recombinant polymerase chain reaction. Deletion of the G box element resulted in a loss of gene expression in the leaves of transgenic tobacco, while deletion of the GT motif caused a 10–100-fold increase in expression in roots. However, site-directed mutagenesis of the GT motif resulted in expression patterns identical to the normal promoter. These experiments demonstrated that light-inducible and tissue-specific expression of the Rca promoter involves multiple cis elements proximal to the transcription start site, and that interactions between these elements are essential for regulating expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042347
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    Two related, low-temperature-induced genes from Brassica napus are homologous to the human tumour bbc1 (breast basic conserved) gene (1993)
    Springer
    Plant molecular biology 23 (1993), S. 1211-1221 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; cold acclimation ; gene isolation ; human tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to identify genes involved in cold acclimation, we have constructed a cDNA library from Brassica napus (cv. Samouraï) cold-acclimated etiolated seedlings. By differential screening, a cDNA clone named pBnC24 (Brassica napus Cold), corresponding to a new cold-inducible plant gene, was isolated. Northern blot hybridizations using total RNA from acclimated and unacclimated seedlings confirmed that BnC24 represents a cold-regulated gene. In contrast with a number of cold-inducible plant genes, BnC24 does not seem to be responsive to abscisic acid (ABA). In addition, further screening of the ‘cold-acclimated’ cDNA library using pBnC24 cDNA as a probe, allowed the isolation of a second type of homologous cDNA. Sequence analysis showed that the two BnC24 genes encode basic 24 kDa proteins, which are highly hydrophilic and rich in alanine, lysine and arginine. The nucleotide and deduced amino acid sequences of these clones do not show any homology with other previously described cold-induced plants genes. However they have strong homology with a recently discovered human tumour gene, bbc1 (breast basic conserved), which seems to be highly conserved in eukaryotes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042354
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  • 83
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    The myrosinase (thioglucoside glucohydrolase) gene family in Brassicaceae (1993)
    Springer
    Plant molecular biology 23 (1993), S. 511-524 
    Details
    ISSN: 1573-5028
    Keywords: Brassicaceae ; Brassica napus ; glucosinolate ; myrosinase ; multigene family ; thioglucoside glucohydrolase (EC 3.2.3.1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The glucosinolate hydrolyzing enzymes myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) are encoded by a multigene family consisting of two subgroups. The first two nuclear genes representing each of these two subgroups of the new gene family, Myr1.Bn1 and Myr2.Bn1, from Brassica napus have been cloned and sequenced. Based on conserved regions in cDNA of three species, PCR (polymerase chain reaction) primers were made, and used to amplify and characterize the structure of the myrosinase genes in seven species of Brassiceae. Southern hybridization analysis of PCR products and genomic DNA indicates that myrosinase is encoded by at least 14 genes in B. napus, with similar numbers in the other species of Brassicaceae investigated. The Myr1 gene cloned from B. napus has a 19 amino acid signal peptide and consists of 11 exons of sizes ranging from 54 to 256 bp and 10 introns of sizes from 75 to 229 bp. The Myr2 gene has a 20 amino acid signal peptide and consists of 12 exons ranging in size from 35 to 262 bp and 11 introns of sizes from 81 to 131 bp. The exons from the two genes have 83% homology at the amino acid level. The intron-exon splice sites are of GT..AG consensus type. The signal peptides and presence of sites for N-linked glycosylation, suggest transport and glycosylation through the ER-Golgi complex. The differences between the two genes are discussed on the basis of their predicted expression at different developmental stages in the plant. Both genes show homology to a conserved motif representing the glycosyl hydrolase family of enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019299
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  • 84
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    Isolation and characterization of two Brassica napus embryo acyl-ACP thioesterase cDNA clones (1993)
    Springer
    Plant molecular biology 23 (1993), S. 769-778 
    Details
    ISSN: 1573-5028
    Keywords: acyl ; Brassica napus ; fatty acid synthesis ; plastidial location ; seed ; thioesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acyl-ACP thioesterases are involved in regulating chain termination of fatty acid biosynthesis in plant systems. Previously, acyl-ACP thioesterase purified from Brassica napus seed tissue has been shown to have a high preference for hydrolysing oleoyl-ACP. Here, oligonucleotides derived from B. napus oleoyl-ACP thioesterase protein sequence data have been used to isolate two acyl-ACP thioesterase clones from a B. napus embryo cDNA library. The two clones, pNL2 and pNL3, contain 1642 bp and 1523 bp respectively and differ in the length of their 3′ non-coding regions. Both cDNAs contain open reading frames of 366 amino acids which encode for 42 kDa polypeptides. Mature rape thioesterase has an apparent molecular weight of 38 kDa on SDS-PAGE and these cDNAs therefore encode for precursor forms of the enzyme. This latter finding is consistent with the expected plastidial location of fatty acid synthase enzymes. Northern blot analysis shows thioesterase mRNA size to be ca. 1.6 kb and for the thioesterase genes to be highly expressed in seed tissue coincident with the most active phase of storage lipid synthesis. There is some sequence heterogeneity between the two cDNA clones, but overall they are highly homologous sharing 95.7% identity at the DNA level and 98.4% identity at the amino acid level. Some sequence heterogeneity was also observed between the deduced and directly determined thioesterase protein sequences. Consistent with the observed sequence heterogeneity was Southern blot data showing B. napus thioesterase to be encoded by a small multi-gene family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021532
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    Transfer of resistance to the beet cyst nematode (Heterodera Schachtii Schm.) from Sinapis alba L. (white mustard) to the Brassica napus L. gene pool by means of sexual and somatic hybridization (1993)
    Springer
    Theoretical and applied genetics 85 (1993), S. 688-696 
    Details
    ISSN: 1432-2242
    Keywords: Intergeneric crosses ; Somatic hybridization ; Sinapis alba ; Brassica napus ; Heterodera schachtii ; Nematode resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sexual and somatic hybrid plants have been produced between Sinapis alba L. (white mustard) and Brassica napus L. (oil-seed rape), with the aim to transfer resistance to the beet cyst nematode Heterodera schachtii Schm. (BCN) from white mustard into the oil-seed rape gene pool. Only crosses between diploid accessions of S. alba (2n = 24, Sa1Sa1) as the pistillate parent and several B. napus accessions (2n = 38, AACC) yielded hybrid plants with 31 chromosomes. Crosses between tetraploid accessions of S. alba (2n = 48, Sa1Sa1Sa1Sa1) and B. napus were unsuccessful. Somatic hybrid plants were also obtained between a diploid accession of S. alba and B. napus. These hybrids were mitotically unstable, the number of chromosomes ranging from 56 to more than 90. Analysis of total DNA using a pea rDNA probe confirmed the hybrid nature of the sexual hybrids, whereas for the somatic hybrids a pattern identical to that of B. napus was obtained. Using chloroplast (cp) and mitochondrial (mt) DNA sequences, we found that all of the sexual F1 hybrids and somatic hybrids contained cpDNA and mtDNA of the S. alba parent. No recombinant mtDNA or cpDNA pattern was observed. Three BC1 plants were obtained when sexual hybrids were back-crossed with B. napus. Backcrossing of somatic hybrids with B. napus was not successful. Three sexual hybrids and one BC1 plant, the latter obtained from a cross between a sexual hybrid and B. napus, were found to show a high level of BCN resistance. The level of BCN resistance of the somatic hybrids was in general high, but varied between cuttings from the same plant. Results from cytological studies of chromosome association at meiotic metaphase I in the sexual hybrids suggest partial homology between chromosomes of the AC and Sa1 genomes and thus their potential for gene exchange.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225006
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    Abundance and polymorphism of simple repetitive DNA sequences in Bmssica napus L. (1993)
    Springer
    Theoretical and applied genetics 85 (1993), S. 994-1000 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; DNA fingerprinting ; Simple repetitive sequences ; Cultivar identification ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Brassica napus genome has been investigated by DNA fingerprinting with six synthetic oligonucleotide probes complementary to simple repetitive sequences, namely (GATA)4, (GACA)4, (GGAT)4, (CA)8, (CT)8 and (GTG)5. While all sequence motifs were found to be present in the B. napus genome, their organization and abundance varied considerably. Among the investigated probes, (GATA)4 revealed the highest level of intraspecific polymorphism and distinguishes not only between cultivars but even between different individuals belonging to the same cultivar. In contrast, (GTG)5, (GACA)4 and (GGAT)4 produced relatively homogeneous fingerprint patterns throughout different cultivars, while hybridization to (CT)8 and (CA)8 resulted in only a few weak bands superimposed on a smear. The isoschizomeric pair Hpa II and Msp I revealed the presence of methylated cytosines in the vicinity of (GATA)m repeats. The applicability of simple repetitive sequence polymorphisms as molecular markers for Brassica species is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215039
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    Nuclear DNA synthesis during the induction of embryogenesis in cultured microspores and pollen of Brassica napus L. (1993)
    Springer
    Theoretical and applied genetics 87 (1993), S. 9-16 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; BrdU ; Embryogenesis ; Microspore and pollen culture ; DNA synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The dynamics of nuclear DNA synthesis were analysed in isolated microspores and pollen of Brassica napus that were induced to form embryos. DNA synthesis was visualized by the immunocytochemical labelling of incorporated Bromodeoxyuridine (BrdU), applied continuously or as a pulse during the first 24 h of culture under embryogenic (32 °C) and non-embryogenic (18 °C) conditions. Total DNA content of the nuclei was determined by microspectrophotometry. At the moment of isolation, microspore nuclei and nuclei of generative cells were at the G1, S or G2 phase. Vegetative nuclei of pollen were always in G1 at the onset of culture. When microspores were cultured at 18 °C, they followed the normal gametophytic development; when cultured at 32 °C, they divided symmetrically and became embryogenic or continued gametophytic development. Because the two nuclei of the symmetrically divided microspores were either both labelled with BrdU or not labelled at all, we concluded that microspores are inducible to form embryos from the G1 until the G2 phase. When bicellular pollen were cultured at 18 °C, they exhibited labelling exclusively in generative nuclei. This is comparable to the gametophytic development that occurs in vivo. Early bicellular pollen cultured at 32 °C, however, also exhibited replication in vegetative nuclei. The majority of vegetative nuclei re-entered the cell cycle after 12 h of culture. Replication in the vegetative cells preceded division of the vegetative cell, a prerequisite for pollen-derived embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223736
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    Frequency and distance of pollen dispersal from transgenic oilseed rape (Brassica napus) (1993)
    Springer
    Transgenic research 2 (1993), S. 356-364 
    Details
    ISSN: 1573-9368
    Keywords: Brassica napus ; oilseed rape ; transgenic crops ; pollen dispersal ; insect pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The objective of this study was to evaluate pollen dispersal inBrassica napus (oilseed rape). The selectable marker, used to follow pollen movement, was a dominant transgene (bar) conferring resistance to the herbicide glufosinate-ammonium. Transgenic and non-transgenic plants of the cultivar Westar were planted in a 1.1 ha field trial, with the transgenic plants in a 9 m diameter circle at the centre, surrounded by non-transgenic plants to a distance of at least 47 m in all directions. A 1 m circle of non-transgenic plants was sown in the centre of the transgenic area to allow estimation of the level of pollen dispersal when plants were in close contact. Honeybee hives were placed at the trial site to optimize the opportunity for cross-pollination. During the flowering period, regular observations were made of the number of plants flowering and the number and type of insects present in 60 1 m2 areas. These areas were located uniformly around the plot at distances of 1, 3, 6, 12, 24, 36 and 47 m from the edge of the 9 m circle of transgenic plants. Seed samples were harvested from each of the 7 distances so that approximately 20% of the circumference of the plot was sampled at each distance. The centre non-transgenic circle was also sampled. Plants were grown from the seed samples and sprayed with glufosinate to estimate the frequency of pollen dispersal at each distance. In order to screen enough samples to detect low frequency cross-pollination events, seed samples were tested in the greenhouse and on a larger scale in the field. Results were confirmed by testing progeny for glufosinate resistance and by Southern blot analysis. The estimated percentage of pollen dispersal in the non-transgenic centre circle was 4.8%. The frequency was estimated to be 1.5% at a distance of 1 m and 0.4% at 3 m. The frequency decreased sharply to 0.02% at 12 m and was only 0.00033% at 47 m. No obvious directional effects were detected that could be ascribed to wind or insect activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01976177
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  • 89
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    Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro (1993)
    Springer
    Protoplasma 172 (1993), S. 154-165 
    Details
    ISSN: 1615-6102
    Keywords: Brassica napus ; Cell division ; High temperature ; Microspore ; Embryogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.
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    URL: http://dx.doi.org/10.1007/BF01379373
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  • 90
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    The effects of abscisic acid on the maturation ofBrassica napus somatic embryos (1993)
    Springer
    Protoplasma 174 (1993), S. 147-157 
    Details
    ISSN: 1615-6102
    Keywords: Abscisic acid ; Brassica napus ; Embryo maturation ; Reserves metabolism ; Somatic embryos ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparison of embryos, cultured for increasing periods of time with and without abscisic acid (ABA), was undertaken to investigate, at the ultrastructural level, the influence of this growth regulator on the maturation of rapeseed (Brassica napus) somatic embryos. In the absence of ABA, the embryos germinated precociously while lipid bodies (LB), which were not numerous, soon degraded, as revealed by a depletion process associated with the appearance of morphologically mature glyoxysomes and an increase in the number of mitochondria. Moreover, a lack of protein bodies indicated that storage protein accumulation was not initiated under these conditions. On the contrary, the addition of ABA (10 μM) induced marked modification of embryo metabolism. Indeed, ABA completely prevented precocious embryo germination and inhibited lipid reserve catabolism. Moreover, the formation of small vacuoles and proliferation of rough endoplasmic reticulum in their vicinity suggested the onset of storage protein accumulation. After 15 days in the presence of ABA, the embryos contained abundant lipid and protein bodies. Nevertheless, these somatic embryos were not exactly the same as their mature zygotic counterparts since differences were found in chloroplasts, amyloplasts, and nuclear structures. These observations suggest that additional factors might be required to obtain fully mature somatic embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379047
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  • 91
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    Somatic homologous recombination in planta: The recombination frequency is dependent on the allelic state of recombining sequences and may be influenced by genomic position effects (1993)
    Springer
    Molecular genetics and genomics 237 (1993), S. 33-40 
    Details
    ISSN: 1617-4623
    Keywords: Intrachromosomal recombination ; Recombination frequency ; Allelic position ; Non-allelic position ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously described a non-selective method for scoring somatic recombination in the genome of whole plants. The recombination substrate consists of a defective partial dimer of Cauliflower Mosaic Virus (CaMV) sequences, which can code for production of viable virus only upon homologous recombination; this leads to disease symptoms on leaves. Brassica napus plants (rapeseed) harbouring the recombination substrate as a transgene were used to examine the time in plant development at which recombination takes place. The analysis of three transgene loci revealed recombination frequencies specific for each locus. Recombination frequencies were increased if more than one transgene locus was present per genome, either in allelic (homozygosity of the transgene locus) or in non-allelic positions. In both cases, the overall recombination frequency was found to be elevated to approximately the sum of the frequencies for the individual transgene loci or slightly higher, suggesting that the respective transgene loci behave largely independently of each other. For all plants tested (single locus, two or multiple loci) maximal recombination frequencies were of the order of 10−6 events per cell division.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282781
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  • 92
    Electronic Resource
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    A study of some factors affectingAgrobacterium transformation and plant regeneration ofDendranthema grandiflora Tzvelev (syn.Chrysanthemum morifolium Ramat.) (1993)
    Springer
    Plant cell, tissue and organ culture 33 (1993), S. 171-180 
    Details
    ISSN: 1573-5044
    Keywords: Agrobacterium ; Dendranthema grandiflora ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In an attempt to develop a system for producing transformed plants from explants ofDendranthema grandiflora, the susceptibility of the cultivar Super White to various wild-type strains ofAgrobacterium tumefaciens andA. rhizogenes was investigated. Tumour formation was not a reliable indicator of the ability of a related disarmed strain to mediate transformation. Following inoculation of explants with disarmedAgrobacterium strains, a number of shoots developed on selective media. However, none of these shoots were transformed. By co-cultivating stem internode explants with a mixed inoculum of wild-type and disarmed strains, it was possible to obtain a callus stably transformed withAgrobacterium carrying a disarmed T-DNA. Histological analysis of explants revealed that shoot regeneration initially occurred from the cells of the epidermis and subsequently from the cortex. However, the cells which were susceptible to T-DNA transfer were confined to the vascular tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01983231
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  • 93
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    Regeneration and somaclonal variation in apomictic Paspalum dilatatum Poir (1993)
    Springer
    Euphytica 67 (1993), S. 71-78 
    Details
    ISSN: 1573-5060
    Keywords: Paspalum dilatatum ; apomixis ; common dallisgrass ; plant regeneration ; somaclonal variation ; fertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In an attempt to incorporate variation into a uniform obligate apomict, plants of apomictic common dallisgrass, Paspalum dilatatum Poir., were regenerated from callus derived from immature inflorescences. Plants developed through both organogenesis and embryogenesis. A total of 682 regenerants were produced and more than 400 were transplanted into a field nursery and screened for somaclonal variation. Eventually 20 regenerants were selected, increased, and planted into a replicated nursery along with normal common dallisgrass. The characteristics examined were maturity date, plant height, number of racemes per inflorescence, number of spikelets per raceme, pubescence, stigma and anther color, ergot resistance, seed germination, seed set, pollen stainability, method of reproduction, and chromosome number. There were differences among the regenerants and between them and common dallisgrass for all traits except chromosome number, stigma and anther color, and ergot resistance. One of the more important regenerants had significantly higher seed set than common dallisgrass. All regenerants reproduced by aposporous apomixis but some exhibited a high degree of abortion while others had more aposporous embryo sacs per ovule than common dallisgrass. These findings demonstrate that common dallisgrass can be regenerated through tissue culture and that somaclonal variation is expressed in some of the regenerants, even though some of the altered traits are deleterious.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00022727
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  • 94
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    Segregation and linkage analysis of DNA markers in microspore derived and F2 populations of oilseed rape (Brassica napus L.) (1993)
    Springer
    Euphytica 74 (1993), S. 59-65 
    Details
    ISSN: 1573-5060
    Keywords: Brassica napus ; microspore derived population ; RAPD ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The segregation of RFLP and RAPD markers was compared in two oilseed rape (Brassica napus L.) breeding populations from the cross ‘Topas’ x R4, the latter being a low linolenic mutation line. A total progeny of 68 F2 and 40 microspore derived plants were studied with 25 markers. The results indicated a significant excess of ‘Topas’ alleles at five RAPD loci in the microspore derived population. This suggests that genomic regions which probably affect microspore culture ability do not have identical distribution in the two population types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00033768
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  • 95
    Electronic Resource
    Electronic Resource
    Growth and ion accumulation of two rapid-cycling Brassica species differing in salt tolerance (1993)
    Springer
    Plant and soil 153 (1993), S. 19-31 
    Details
    ISSN: 1573-5036
    Keywords: Brassica carinata ; Brassica napus ; calcium ; chloride ; growth analysis ; leaf area ratio ; magnesium ; net assimilation rate ; potassium ; relative growth rate ; seawater ; sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The response of two rapid-cycling Brassica species differing in tolerance to seawater salinity was studied over a period of 24 days. In response to 8 dS m−1 salinity, the two Brassica species showed clear differences in the changes in relative growth rate (RGR), net assimilation rate (NAR) and leaf area ratio (LAR). The RGR of B. napus was slightly reduced by salinity, wheareas the RGR of B. carinata was largely reduced in the early stages of salinization. LAR of B. napus was affected by salinity in the later stages of growth and significantly correlated with the reduction in RGR. On the other hand, the NAR of B. carinata was decreased by salinity, corresponding to the decrease of the RGR of B. carinata. The NAR of B. napus was not significantly affected by salinity according to analysis of covariance. The shoot concentrations of Na, Mg and Cl increased while the concentrations of K and Ca decreased sharply during the first 5 days of salinization; subsequently, all ion concentrations remained relatively constant. The concentrations of Na, K, Ca, Mg and Cl in the root were similarly affected by salinity. There were no significant differences of ion concentrations between species that could be related to the differences in salt tolerance. Thus, the differences in salt tolerance between species can not be related to differences in specific-ion effects, but may be related to some factor that reduces the NAR of B. carinata during the early stages of growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010541
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  • 96
    Electronic Resource
    Electronic Resource
    Release of nonexchangeable potassium from different size fractions of two highly K-fertilized soils in the rhizosphere of rape (Brassica napus cv Drakkar) (1993)
    Springer
    Plant and soil 155-156 (1993), S. 403-406 
    Details
    ISSN: 1573-5036
    Keywords: Brassica napus ; K release ; nonexchangeable potassium ; particle size ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The release of nonexchangeable potassium by the different particle size fractions of two soils was studied with a culture device designed to confine soil samples in the rhizosphere of rape (Brassica napus cv Drakkar). After 8 days of cropping, the contribution of nonexchangeable K to K uptake ranged from 50% in the fine clay to 80–100% in the coarser fractions. Due to their high supplying power and their relative abundance, the silt fractions provided a major part of the supply of K by these soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025068
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  • 97
    Electronic Resource
    Electronic Resource
    The role of endogenous auxin in root initiation (1993)
    Springer
    Plant growth regulation 13 (1993), S. 77-84 
    Details
    ISSN: 1573-5087
    Keywords: Agrobacterium rhizogenes ; auxin ; indole-3-acetic acid (IAA) ; root initiation ; sensitivity ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper is the second part of a review which considers evidence for the involvement of auxin in root initiation. Part II examines the research being carried out with transformed plant tissues. Agrobacterium rhizogenes causes abundant root initiation at the site of inoculation. Ri plasmid T-DNA contains several genes which encode enzymes involved in the biosynthesis and metabolism of indole-3-acetic acid. Transfer of various fragments of the Ri plasmid has also been reported to confer increased sensitivity to auxin upon plant cells. Controlled expression of these genes in the plant genome potentially offer an insight for developmental plant physiologists into the role of plant growth substances in the process of root initiation. The importance of absolute levels of IAA in the stimulation of root initiation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207595
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  • 98
    Electronic Resource
    Electronic Resource
    Genetic engineering of grain and pasture legumes for improved nutritive value (1993)
    Springer
    Genetica 90 (1993), S. 181-200 
    Details
    ISSN: 1573-6857
    Keywords: plant ; genetic engineering ; nutritive value ; agrobacterium ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This review describes work aimed at the improvement of the nutritive value of grain and forage legumes using gene transfer techniques. Two traits which are amenable to manipulation by genetic engineering have been identified. These are plant protein quality and lignin content. In order to increase the quality of protein provided by the legume grains peas and lupins, we are attempting to introduce into these species chimeric genes encoding a sunflower seed protein rich in the sulphur-containing amino acids methionine and cysteine. These genes are designed to be expressed only in developing seeds of transgenic host plants. Chimeric genes incorporating a similar protein-coding region, but different transcriptional controls, are being introduced into the forage legumes lucerne and subterranean clover. In this case the genes are highly expressed in the leaves of transformed plants, and modifications have been made to the sunflower seed protein-coding sequences in order to increase the stability of the resultant protein in leaf tissue. Another approach to increasing plant nutritive value is represented by attempts to reduce the content of indigestible lignin in lucerne.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01435039
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  • 99
    Electronic Resource
    Electronic Resource
    Restoring adventitious shoot formation on chrysanthemum leaf explants following cocultivation with Agrobacterium tumefaciens (1993)
    Springer
    Plant cell, tissue and organ culture 32 (1993), S. 263-270 
    Details
    ISSN: 1573-5044
    Keywords: Dendranthema grandiflora ; preculture ; regeneration ; transformation ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Explants from leaves of in vitro-grown chrysanthemum (Dendranthema grandiflora Tzvel.) cultivars regenerated adventitious shoots without an intermediate callus phase. Puncturing explants with a brush increased regenerations, but in combination with cocultivation with Agrobacterium tumefaciens it had an adverse effect on shoot formation. The negative effect of brushing and cocultivation could be overcome by preculturing explants for 8 days. Preculture altered the location of transformed sites but did not inhibit transformation. Regeneration following cocultivation with Agrobacterium is also encouraged if alternative regeneration protocols are used that do not require brushing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042287
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  • 100
    Electronic Resource
    Electronic Resource
    Prediction of F6 line performance from F3 families in spring oilseed rape. I. Yield and other agronomic traits (1993)
    Springer
    Euphytica 69 (1993), S. 141-147 
    Details
    ISSN: 1573-5060
    Keywords: Brassica napus ; cross prediction ; genetic parameters ; oilseed rape ; SSD lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The reliability of a selection among crosses based on a cross prediction in early generations was investigated in spring rapeseed. The performance of the parents, the F2 generation, and random F3 lines from four crosses were used to predict the probability of finding superior recombinant lines. These predictions were made for two years and compared with the observed performance of F6 lines in the second of these two years and in an additional year. Predicted and observed performances coincided reasonably for the characters plant height, standability, maturity and an index calculated from seed yield, oil content and protein content. For seed yield and flowering time, the predictions were very unreliable. In conclusion, prediction methods may be useful in rapeseed breeding, if quality traits are of major commercial interest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021738
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