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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 79 (1990), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: By measuring uptake of the membrane impermeable dye. phenosafranine, it can be shown that the plasma membrane of intact cells within cell aggregates can be reversibly permeabilized by electroporation. However, the plant cell wall is a barrier to DNA uptake by intact cells, although under certain circumstances expression of DNA, electroporated into intact cells, can be demonstrated. The level of expression is about 20–50 times lower than that obtained by electroporation of protoplasts, and depends on cell wall properties and pretreatments of cell aggregates. In contrast, efficient transformation of whole cells of bacteria and yeasts can be achieved by electroporation. Factors which influence DNA transfer into whole plant cells and the possibility of stable transformation are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 2 (1979), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Conditions are described for measuring the starch content of plant tissues or extracts as glucose over the range from 10−7 mol to 10−14 mol. The method is based on the hydrolysis of gelatinized starch by amyloglucosidase; the glucose released is measured by reduction of NADP+ by coupled enzymic reactions.The NADPH is determined directly either spectrophotometrically or fluorimetrically, or after enzymic amplification. Amyloglucosidases were tested for contaminating enzymes which might degrade glucans other than starch, and a commercial preparation from Rhizopus niveus was found to be suitable for use without pretreatments. Glucose present in tissues and extracts may be measured and subtracted from starch values using appropriate blanks, or first destroyed by dilute alkali and heat. Addition of α-amylase to amyloglucosidase during starch hydrolysis was not found to increase percentage hydrolysis from the normal range of 86–99% from starches of different sources.The procedures described are rapid and several orders of magnitude more sensitive than current methods, and can be used to measure the starch content of single cells.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 85 (1975), S. 15-37 
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparison of transmembrane potential (pd) properties of parenchyma cells and giant transfer cells induced by a root-knot nematode in the roots ofImpatiens balsamina has been made. Apart from some differences in rate of response to a few treatments, parenchyma and giant cells had similar pd values; active and passive components of the pd (cyanide, azide); responses to total ion concentration, pH and potassium concentration; responses to protein synthesis inhibitors (puromycin, cycloheximide and actinomycin D) and responses to sugars. Both parenchyma cells and giant cells are depolarized by puromycin, cycloheximide and actinomycin D. The cells recover from the depolarization in the presence of cycloheximide, suggesting that this presumed protein synthesis inhibitor does not act in a straight-forward manner. The cells do not recover in the presence of puromycin or actinomycin D. Parenchyma cells and giant cells clearly have different metabolic rates and ion fluxes, but their pd responses are the same. This suggests that the pd does not reflect metabolic activity or ion fluxes of a cell, but is strictly controlled in itself. Part of this control may be via a feedback mechanism acting on an electrogenic pump. The depolarization caused by glucose is induced by aging the cells after excision. The effect is discussed in terms of an H+ dependent cotransport system and an ATPase permease system. The apparent normality of pd responses of nematode-induced giant transfer cells suggests that they may be a useful model system for experiments on higher plant cells.
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  • 4
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protoplasts have been isolated from three tuber-bearing Solanum species, S. hjertingii, S. polyadenium and S. capsicibaccatum, that are sexually incompatible with S. tuberosum, but possess potentially useful characters. For isolating protoplasts from leaves of in vitro shoot cultures of S. hjertingii and S. capsicibaccatum growth was improved by including silver thiosulfate in the medium. However, for S. polyadenium, leaves of pot-grown plants were the best source for protoplasts. Following protoplast division and culture, plants were regenerated from protoplasts of each of the species. The pattern of chromosome variation in regenerants was similar to that observed for other diploid and tetraploid Solanum species. The results indicate that it should be possible to introduce the potentially useful germplasm from these wild species into somatic hybrids with S. tuberosum by protoplast fusion.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 85 (1993), S. 729-734 
    ISSN: 1432-2242
    Keywords: Protoplast fusion ; Gamma irradiation ; Partial genome transfer ; Solanum tuberosum ; Solanum brevidens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Asymmetric somatic hybrids were obtained by fusion of Solanum tuberosum (PDH40) protoplasts with 300- or 500-Gy irradiated protoplasts of S. brevidens. These radiation doses were sufficient to prevent the growth of the S. brevidens protoplasts. Putative hybrids were selected on the basis of phenotype from regenerated shoots and identified with a S. brevidens-specific probe. From these, 31 asymmetric hybrids were confirmed by morphological characteristics, isoenzyme patterns and RFLP analysis. The morphology of the asymmetric hybrids was intermediate between that of S. tuberosum and symmetric hybrids of both species (obtained without irradiation treatment). Chromosome counts from 17 asymmetric hybrids showed that the chromosome number of the hybrids ranged from 31 to 64. The asymmetric hybrids probably had one or two genome complements (i.e. either 24 or 48 chromosomes) from S. tuberosum and 7–22 chromosomes from S. brevidens. There was no clear correlation between the radiation dose and the degree of elimination of the S. brevidens genome.
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  • 6
    ISSN: 1432-2242
    Keywords: Potato ; S. brevidens ; Mitchondrial DNA ; Somatic hybrids ; Non-radioactive labelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitochondrial (mt) DNAs of somatic hybrids obtained by electrical and chemical fusion of mesophyll protoplasts of S. brevidens and a dihaploid line of S. tuberosum PDH 40 were analysed by Southern hybridization using the digoxigenin-labelled mtDNA sequences nad5 or orf25. In the Southern analysis of the hybrid mtDNA probed with nad5, most of the 19 hybrids analyzed had an RFLP pattern similar, but not identical, to one of the parents, S. tuberosum, PDH40. Nineteen percent of the hybrids had most of the S. brevidens fragments. Five of the hybrids had an identical RFLP pattern to either one of the parents while another two hybrids had novel RFLP patterns. Similar results were obtained by Southern analysis with orf25. These results clearly show that mtDNA rearrangements had occurred at a high frequency in the somatic hybrids. There were no differences in the frequencies of rearrangements observed between the hybrids regenerated from chemical and electrical fusions.
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  • 7
    ISSN: 1432-2242
    Keywords: Potato ; Solanum brevidens ; Somatic hybrids ; Species-specific probes ; Squash blots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To aid in the identification and analysis of somatic hybrids between potato (Solanum tuberosum, dihaploid line PDH 40) and the non tuber-bearing wild species S. brevidens, a series of species-specific repetitive DNA sequences have been isolated. This was accomplished by making libraries of HaeIII-digested total DNA of S. tuberosum and S. brevidens, by cloning fragments into the SmaI site of plasmid pUC18 and transforming them into E. coli (JM83). The S. brevidens library consisted of 1,000 recombinant clones, and that of S. tuberosum, 700. Nitrocellulose filters with recombinant clones were hybridised to nick-translated total DNA of S. brevidens and also S. tuberosum, and, following autoradiography, clones that hybridised strongly to the DNA of only one of the species were chosen. Two highly repeated S. brevidens clones (pSB1, 400 bp and pSB7,210 bp), one highcopy-number s. tuberosum clone (pST10, 200 bp) and one low-copy-number sequence of S. tuberosum (pST3, 1.5 kbp) were selected for further analysis by Southern hybridisation to digested total DNA. Clone pSB7 gave a ladder pattern on hybridisation to EcoR1-digested total DNA of S. brevidens, with signals at multiples of 200 bp DNA. Using these probes it was possible to verify the hybridity of putative hybrids of dihaploid S. tuberosum and S.brevidens, and to confirm by Southern analysis and by slot blots the parental genome dosage of hexaploid hybrids (two s. brevidens: one S. tuberosum, and vice-versa). The S. tuberosum-specific probe, pSTIO, hybridised with DNA of three other tuber-bearing wild species (S. hjertingii, S. capsicibaccatum and S. berthaultii). A squash-blot procedure was developed using the probes that would allow early identification of somatic hybrid callus. There are a number of useful applications of such species-specific probes in the identification and analysis of somatic hybrids.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 87 (1976), S. 273-279 
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The morphology of wall ingrowths in xylem and phloem transfer cells inHelianthemum is different. It is possible to use nematode infection to induce the formation of giant cells which abut both xylem and phloem elements to test whether ingrowth morphology is controlled by the solutes presumed to be transported across the plasmalemma of the cells. This experiment has been done and it is found that although wall ingrowths develop against both xylem and phloem, the giant cells exhibit only the ingrowth structure characteristic of xylem transfer cells.
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  • 9
    Publication Date: 1979-09-01
    Print ISSN: 0140-7791
    Electronic ISSN: 1365-3040
    Topics: Biology
    Published by Wiley
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