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  • 1990-1994  (32)
  • 1955-1959
  • 1992  (32)
  • Industrial Chemistry
  • somaclonal variation
  • transformation
  • 1
    Electronic Resource
    Electronic Resource
    Plasmid mediated metal and antibiotic resistance in marinePseudomonas (1992)
    Springer
    BioMetals 5 (1992), S. 73-80 
    Details
    ISSN: 1572-8773
    Keywords: mercury ; arsenic ; cadmium ; plasmid ; restriction analysis ; curing ; conjugation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Pseudomonas sp isolated from the Bay of Bengal (Madras coast) contained a single large plasmid (pMR1) of 146 kb. Plasmid curing was not successful with mitomycin C, sodium dodecyl sulfate, acridine orange, nalidixic acid or heat. Transfer of mercury resistance from marinePseudomonas toEscherichia coli occurred during mixed culture incubation in liquid broth at 10−4 to 10−5 ml−1. However, transconjugants lacked the plasmid pMR1 and lost their ability to resist mercury. Transformation of pMR1 intoE. coli competent cells was successful; however, the efficiency of transformation (1.49×102 Hgr transformants μg−1 pMR1 DNA) was low.E. coli transformants containing the plasmid pMR1 conferred inducible resistance to mercury, arsenic and cadmium compounds similar to the parental strain, but with increased expression. The mercury resistant transformants exhibited mercury volatilization activity. A correlation existed between metal and antibiotic resistance in the plasmid pMR1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01062217
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  • 2
    Electronic Resource
    Electronic Resource
    Stably transformed herbicide resistant callus of sugarcane via microprojectile bombardment of cell suspension cultures and electroporation of protoplasts (1992)
    Springer
    Plant cell reports 11 (1992), S. 494-498 
    Details
    ISSN: 1432-203X
    Keywords: Sugarcane ; cell suspension ; protoplast ; microprojectile bombardment ; electroporation ; GUS ; bar ; PAT ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stably transformed callus of a hybrid sugarcane cultivar (Saccharum species hybrid, CP72-1210) was achieved following high velocity microprojectile bombardment of suspension culture cells, and electroporation of protoplasts. A three-day old cell suspension culture (SC88) was bombarded with gold particles coated with pBARGUS plasmid DNA containing the ß-glucuronidase (GUS) reporter gene and the bar selectable gene that confers resistance to the herbicide basta. The pBARGUS plasmid was also electroporated into the protoplasts of another cell line (SCPP). Colonies resistant to basta were recovered from both sources. Stable integration of the bar gene in the resistant cell lines was confirmed by Southern analysis. In addition, phosphinothricin acetyltransf erase (PAT) activity was also demonstrated in the transformed cell lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236264
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  • 3
    Electronic Resource
    Electronic Resource
    Transformation of vitis tissue by different strains of Agrobacterium tumefaciens containing the T-6b gene (1992)
    Springer
    Plant cell reports 11 (1992), S. 192-195 
    Details
    ISSN: 1432-203X
    Keywords: Grapevine ; Agrobacterium tumefaciens ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Stem pieces and leaf disks of Vitis spp. were cocultured with Agrobacterium tumefaciens strains carrying the UidA (ß-glucuronidase = GUS) gene. The transformation efficiency was highly increased by using a modified T-6b gene (a gene from pTiTm4) which interferes with normal growth and allows regeneration of normal Nicotiana rustica plants (Tinland 1990). The strains first tested on stem segments were subsequently tested in a leaf explant system. On leaves the transformation efficiency of the strains was much lower than with stems. Both the T-6b gene and the hsp 70-T-6b gene (a modified T-6b gene under the control of a heat shock promoter) allowed the initiation of GUS-positive buds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232531
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  • 4
    Electronic Resource
    Electronic Resource
    Transformation of rapid cycling cabbage (Brassica oleracea var. capitata) with Agrobacterium rhizogenes (1992)
    Springer
    Plant cell reports 11 (1992), S. 334-338 
    Details
    ISSN: 1432-203X
    Keywords: Brassica oleracea ; rapid cycling cabbage ; transformation ; Agrobacterium rhizogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genetically transformed cabbage (Brassica oleracea var. capitata) roots were obtained after inoculation with two engineered Agrobacterium rhizogenes strains, each harbouring a plant selectable marker gene in their T-DNA. Axenic root clones resistant to kanamycin or hygromycin B were established, most of which did not exhibit the phenotypic characteristics of Ri-transformed roots. Shoot regeneration was induced from roots after treatment with 2,4-dichlorophenoxyacetic acid (2,4-D). The resulting plants exhibited various phenotypes: some looked normal, while others showed the transformed phenotype observed in other species. Direct evidence for genetic transformation was obtained by molecular hybridization. The trait was transmitted to the progeny. Transformed cabbage plants can be obtained within 6 months using this approach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233360
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  • 5
    Electronic Resource
    Electronic Resource
    Site-specific oligodeoxynucleotide binding to maize Adh1 gene promoter represses Adh1-GUS gene expression in vivo (1992)
    Springer
    Plant molecular biology 19 (1992), S. 715-723 
    Details
    ISSN: 1573-5028
    Keywords: DNase I footprinting ; β-glucuronidase (GUS) ; H-DNA ; transformation ; triple helix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract There is a 36 bp tract of extreme homopurine/homopyrimidine (PuPy) asymmetry in the maize Adh1 gene promoter (from −44 to −79) that is S1-hypersensitive in plasmids under supercoil tension. Oligodeoxynucleotides corresponding to the PuPy tract were designed to examine the secondary structure of the region and address the possible role of the tract in gene regulation. On the basis of oligodeoxynucleotide band-shift and DNase I footprinting analyses, it was concluded that the homopyrimidine oligodeoxynucleotide can form a triple helix with the duplex PuPy tract in vitro. Transient assays in protoplasts, suspension cells, and seedling roots show that the homopyrimidine oligodeoxynucleotide is also capable of repressing Adh1-GUS gene expression during co-transformation, presumably by the formation of a triple helix with the PuPy tract in vivo. The complementary homopurine oligodeoxynucleotide would not form a triple helix in vitro, nor would it repress Adh1-GUS in vivo. We propose that triple helix formation is a potential regulatory phenomenon in vivo, and that an intraregion triple helix could occur within the Adh1 promoter via the formation of H-DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027068
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  • 6
    Electronic Resource
    Electronic Resource
    Regulation of lysine synthesis in transgenic potato plants expressing a bacterial dihydrodipicolinate synthase in their chloroplasts (1992)
    Springer
    Plant molecular biology 19 (1992), S. 815-823 
    Details
    ISSN: 1573-5028
    Keywords: dihydrodipicolinate synthase ; lysine overproduction ; potato ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The essential amino acid lysine is synthesized in higher plants by a complex pathway that is predominantly regulated by feedback inhibition of two enzymes, namely aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). Although DHPS is thought to play a major role in this regulation, the relative importance of AK is not known. In order to study this regulation, we have expressed in the chloroplasts of transgenic potato plants a DHPS derived from Escherichia coli at a level 50-fold above the endogenous DHPS. The bacterial enzyme is much less sensitive to lysine inhibition than its potato counterpart. DHPS activity in leaves, roots and tubers of the transgenic plants was considerably higher and more resistant to lysine inhibition than in control untransformed plants. Furthermore, this activity was accompanied by a significant increase in level of free lysine in all three tissues. Yet, the extent of lysine overproduction in potato leaves was significantly lower than that previously reported in leaves of transgenic plants expressing the same bacterial enzyme, suggesting that in potato, AK may also play a major regulatory role in lysine biosynthesis. Indeed, the elevated level of free lysine in the transgenic potato plants was shown to inhibit the lysine-sensitive AK activity in vivo. Our results support previous reports showing that DHPS is the major rate-limiting enzyme for lysine synthesis in higher plants, but they suggest that additional plant-specific regulatory factors are also involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027077
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  • 7
    Electronic Resource
    Electronic Resource
    Factors influencing Agrobacterium-mediated transient expression of gusA in rice (1992)
    Springer
    Plant molecular biology 20 (1992), S. 1037-1048 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; rice ; transformation ; Ti plasmid ; GUS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transient expression of GUS in rice (Oryza sativa L.) mediated by Agrobacterium tumefaciens was characterized using binary vectors containing gusA genes that express minimal (pKIWI105 and pCNL1) or no (p35S-GUS-INT and pCNL56) GUS activity in bacteria. Four-day old seedlings obtained from seeds or immature embryos of rice were cut into shoot, root, and seed remnants and inoculated with various strains of A. tumefaciens. Transient GUS expression events were quantitated histochemically by determining the frequency of explants exhibiting blue spots indicative of GUS at four to six days after cocultivation with A. tumefaciens. A. tumefaciens strains that did not contain the gusA gene (At643) or a Ti-plasmid (At563 and At657) did not elicit any blue staining characteristic of GUS activity. Several parameters were important in obtaining efficient transient expression of GUS in rice mediated by A. tumefaciens. The growth regulator 2,4-D inhibited GUS expression if present during the seed germination period, but the presence of 6 mg/1 2,4-D during cocultivation of the explants with A. tumefaciens slightly enhanced GUS expression efficiency. All 21 rice cultivars tested expressed GUS after co-cultivation with A. tumefaciens. The GUS expression frequency was highest amongst the indica cultivars. The frequencies of GUS expression in japonica cultivars and in Oryza glaberrima cultivars (grown primarily in Africa) were generally one-half to one-third the level found for indica varieties. Leaf explants were more susceptible to A. tumefaciens-facilitated GUS expression than were roots or seed remnants. The vir genes of an agropine-type Ti-plasmid of A. tumefaciens were most effective in directing transient GUS expression in rice, whereas those of a nopaline-type and an octopine-type plasmid were less effective. We have also found that the frequency of transient expression of GUS was higher with pBIN19 as the precursor cloning vector than with pEND4K as the precursor cloning vector. Reasons for differences in effectiveness of these binary vectors are discussed. Using the conditions described here, A. tumefaciens-mediated frequencies of transient GUS expression in four-day old shoots of several rice cultivars were routinely in excess of 50%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028891
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  • 8
    Electronic Resource
    Electronic Resource
    Transformation and inheritance of a hygromycin phosphotransferase gene in maize plants (1992)
    Springer
    Plant molecular biology 18 (1992), S. 189-200 
    Details
    ISSN: 1573-5028
    Keywords: hygromycin ; inheritance ; maize ; tissue culture ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Embryogenic maize (Zea mays L.) callus cultures were transformed by microprojectile bombardment with a chimeric hygromycin phosphotransferase (HPT) gene and three transformed lines were obtained by selecting for hygromycin resistance. All lines contained one or a few copies of the intact HPT coding sequence. Fertile, transgenic plants were regenerated and the transmission of the chimeric gene was demonstrated through two complete generations. One line inherited the gene in the manner expected for a single, dominant locus, whereas two did not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034948
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  • 9
    Electronic Resource
    Electronic Resource
    Segregation of transgenes in maize (1992)
    Springer
    Plant molecular biology 18 (1992), S. 201-210 
    Details
    ISSN: 1573-5028
    Keywords: maize ; transformation ; inheritance ; phosphinothricin acetyltransferase ; cotransformation ; microprojectile bombardment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Progeny recovered from backcrossed transgenic maize tissue culture regenerants (R0) were analyzed to determine the segregation, expression, and stability of the introduced genes. Transgenic A188×B73 R0 plants (regenerated from embryogenic suspension culture cells transformed by microprojectile bombardment; see [9]) were pollinated with nontransformed B73 pollen. Inheritance of a selectable marker gene, bar, and a nonselectable marker gene, uidA, was analyzed in progeny (R1) representing four independent transformation events. Activity of the bar gene product, phosphinothricin acetyltransferase (PAT), was assessed in plants comprising the four R1 populations. The number of R1 plants containing PAT activity per total number of R1 plants recovered for each population was 2/7, 19/34, 3/14 and 73/73. Molecular analysis confirmed the segregation of bar in three R1 populations and the lack of segregation in one R1 population. Cosegregation analysis indicated genetic linkage of bar and uidA in all four R1 populations. Analysis of numerous R2 plants derived from crossing transformed R1 plants with nontransformed inbreds revealed 1:1 segregation of PAT activity in three of four lines, including the line that failed to segregate in the R1 generation. Integrated copies of bar in one line appeared to be unstable or poorly transmitted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034949
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  • 10
    Electronic Resource
    Electronic Resource
    Plant transformation: a simple particle bombardment device based on flowing helium (1992)
    Springer
    Plant molecular biology 18 (1992), S. 835-839 
    Details
    ISSN: 1573-5028
    Keywords: transformation ; particle gun ; soybean ; GUS gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We observed that flowing helium at moderate pressures accelerated DNA-coated microprojectiles to velocities suitable for penetration of cells in intact plant tissues. The flowing helium principle permitted the construction of a simple and inexpensive transformation device that was easier to use than those previously described. This device provided efficient transformation of cells in soybean seedlings and other plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020031
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  • 11
    Electronic Resource
    Electronic Resource
    Analysis of the region in between two closely linked patatin genes: class II promoter activity in tuber, root and leaf (1992)
    Springer
    Plant molecular biology 20 (1992), S. 683-694 
    Details
    ISSN: 1573-5028
    Keywords: patatin class II gene ; Solanum tuberosum ; transformation ; transgenic potato ; tuber-specific gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From a potato genomic library a phage lambda clone was isolated that carried nucleotide sequences of two patatin genes, thus demonstrating a close physical linkage between these two members of the patatin gene family. Sequence and restriction analysis showed the genes to be oriented in tandem. The more upstream gene was a pseudogene truncated at the 3′ end, whereas the downstream gene was a class II patatin gene. In addition to a 208 bp fragment also present in patatin class I promoters, the region in between both genes contained various direct repeats also found in other patatin genes. To study the promoter activity of this intergenic region, a 2.78 kb fragment was transcriptionally fused to the β-glucuronidase gene and reintroduced into potato cultivar Bintje. Histochemical analysis revealed expression in the outermost layer of cells of the cortex, in the tuber phellogen, in or around the root vascular system, and also in the abaxial phloem layer of the vascular bundle in leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046453
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  • 12
    Electronic Resource
    Electronic Resource
    Microprojectile bombardment of plant tissues increases transformation frequency by Agrobacterium tumefaciens (1992)
    Springer
    Plant molecular biology 18 (1992), S. 301-313 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; β-glucuronidase ; meristem ; microprojectile bombardment ; neomycin phosphotransferase ; sunflower ; tobacco ; transformation ; wounding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bombardment of plant tissues with microprojectiles in an effective method of wounding to promote Agrobacterium-mediated transformation. Tobacco cv. Xanthi leaves and sunflower apical meristems were wounded by microprojectile bombardment prior to application of Agrobacterium tumefaciens strains containing genes within the T-DNA encoding GUS or NPTII. Stable kanamycin-resistant tobacco transformants were obtained using an NPTII construct from particle/plasmid, particle-wounded/Agrobacterium-treated or scalpel-wounded/Agrobacterium-treated potato leaves. Those leaves bombarded with particles suspended in TE buffer prior to Agrobacterium treatment produced at least 100 times more kanamycin-resistant colonies than leaves treated by the standard particle gun transformation protocol. In addition, large sectors of GUS expression, indicative of meristem cell transformation, were observed in plants recovered from sunflower apical explants only when the meristems were wounded first by particle bombardment prior to Agrobacterium treatment. Similar results in two different tissue types suggest that (1) particles may be used as a wounding mechanism to enhance Agrobacterium transformation frequencies, and (2) Agrobacterium mediation of stable transformation is more efficient than the analogous particle/plasmid protocol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034957
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  • 13
    Electronic Resource
    Electronic Resource
    Evidence for sense RNA-mediated protection to PVYN in tobacco plants transformed with the viral coat protein cistron (1992)
    Springer
    Plant molecular biology 20 (1992), S. 631-639 
    Details
    ISSN: 1573-5028
    Keywords: coat protein ; potato virus Y ; tobacco ; transformation ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The coat protein (CP) cistron of the tobacco veinal necrosis strain of potato virus Y (PVYN), supplemented with translational start signals, was cloned into an Agrobacterium tumefaciens Ti transformation vector. Transformation of tobacco leaf discs resulted in 99 transgenic lines which were subsequently analysed for the presence and expression, at both the transcriptional and translational level, of the CP-gene. Although CP-specific RNA transcripts were produced in all plants no CP could be detected by several sensitive immunological techniques. Upon mechanical inoculation of progeny lines of selfpollinated original transformants (S1) with PVYN, protection levels of 20 and 95%, respectively, could be observed in two out of ten lines tested. This level of protection increased to 100% in the S2 progeny obtained from self-pollination of virus-protected S1 plants. Transformation of tobacco leaf discs with a PVYN CP construct from which the ATG start codon had been removed by site-directed mutagenesis resulted in 57 transgenic lines that all produced CP-specific transcripts. Mechanical inoculation with PVYN of S1 progeny plants of several of these lines resulted in resistance to a similar level and extent as in the S1 progeny of plants transformed with the intact CP cistron. The results obtained strongly suggest that the resistance observed in the transgenic plants is principally based on the presence of PVYN CP RNA sequences rather than on the accumulation of viral coat protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046448
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  • 14
    Electronic Resource
    Electronic Resource
    Transformation of Solanum integrifolium poir via Agrobacterium tumefaciens: Plant regeneration and progeny analysis (1992)
    Springer
    Plant cell reports 11 (1992), S. 11-15 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium tumefaciens ; Solanum integrifolium ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The wild species Solanum integrifolium represents a source of pest and disease resistance genes for breeding strategies of the cultivated species Solanum melongena. Somatic hybridization via protoplast fusion between the two species may provide a valuable tool for transferring polygenic traits into the cultivated species. The availability of S.integrifolium cells carrying dominant selectable markers would facilitate the heterokaryon rescue. An appropriate methodology for in vitro culture and plant regeneration from leaf explants of S.integrifolium is reported. Efficient leaf-disk transformation via co-cultivation with Agrobacterium tumefaciens led to the regeneration of transformed plants carrying the reporter genes GUS and NPT-II. Transformed individuals were obtained through selection on kanamycin-containing medium. Stable genetic transformation was assessed by histochemical and enzymatic assays for GUS and NPT-II activity, by the ability of leaf disks to initiate callus on Km-containing medium, Southern blot analyses of the regenerated plants, and genetic analysis of their progenies. Selfed-seed progeny of individual transformed plants segregated seedlings capable to root and grow in selective condition, while untransformed progeny did not. Genetic analyses of progeny behaviour showed that the reporter gene NPT-II segregated as single as well as two independent Mendelian factors. In two cases an excess of kanamycin-sensitive seedlings was obtained, not fitting into any genetic hypothesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231831
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  • 15
    Electronic Resource
    Electronic Resource
    Transformations of thiocyanoalkyl phosphites and amidophosphites (1992)
    Springer
    Russian chemical bulletin 41 (1992), S. 2119-2120 
    Details
    ISSN: 1573-9171
    Keywords: transformation ; thiocyanoalkyl phosphites ; amidophosphites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The ratio of the alkoxy and dialkylamido groups in thiocyanoalkyl phosphites determines the structure of the transformation products of these compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863384
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  • 16
    Electronic Resource
    Electronic Resource
    Heritable tissue culture induced variation in Zinnia marylandica (1992)
    Springer
    Euphytica 64 (1992), S. 81-89 
    Details
    ISSN: 1573-5060
    Keywords: interspecific hybrid ; somaclonal variation ; Zinnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Adventitious shoots of Zinnia marylandica, an amphidiploid with limited genetic segregation, were regenerated from cotyledonary tissue on Murashige-Skoog (MS) media containing 0.2 or 22.2 μM thidiazuron (TDZ) and grown through flowering. Fisher's Test for Equal Variance indicated tissue culture induced plants had more variation than seed-derived control plants. Twelve of 149 (8%) plants derived from 0.2 μM TDZ and three of 23 (13%) plants from 22.2 μM TDZ had variant characters. Aberrant characteristics in self-pollinated variants included plant height, fertility, flower color and morphology, and were sexually transmitted, indicating genetic change had occurred. Aberrant characteristics not observed in regenerated plants arose in progeny.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023541
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  • 17
    Electronic Resource
    Electronic Resource
    Somaclonal variation in plant adaptation to acid soil in the tropical forage legume Stylosanthes guianensis (1992)
    Springer
    Plant and soil 146 (1992), S. 21-30 
    Details
    ISSN: 1573-5036
    Keywords: biomass partitioning ; nutrient uptake ; plant adaptation ; soil acidity ; somaclonal variation ; Stylosanthes guianensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Somaclonal variation offers the possibility to obtain changes in one or a few characters of an otherwise outstanding cultivar without altering the remaining, and often unique, part of the genotype. It has been shown to be heritable for some species. A check line of Stylosanthes guianensis (Aubl.) Sw., CIAT 2243 and 14 somaclones in the R4 generation, selected after three generations from the original 114 plants regenerated from callus cultures, were used in a glasshouse trial. The main objective of the study was to evaluate the physiological basis of the differences in agronomic performance of certain somaclones over the check genotype when grown in a sandy loam acid soil at low or high fertility level. Measurements at the time of harvest (170 days of plant age) included dry matter distribution between shoot and roots, leaf area production, nutrient levels in soil and plant parts, and uptake of nutrients from soil. Somaclones differed with the check genotype in terms of (i) partitioning of fixed carbon between the shoot and roots; (ii) root biomass production and (iii) uptake of nitrogen and phosphorus. Positive relationships were found between total nitrogen uptake and total biomass, and total phosphorus uptake and total biomass, and total phosphorus uptake and total nitrogen uptake. The results of this study provide an insight into the potential use of somaclonal variation for the improvement of plant adaptation to acid soil conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011991
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  • 18
    Electronic Resource
    Electronic Resource
    Hexokinase receptors: Preferential enzyme binding in normal cells to nonmitochondrial sites and in transformed cells to mitochondrial sites (1992)
    Springer
    Journal of bioenergetics and biomembranes 24 (1992), S. 47-53 
    Details
    ISSN: 1573-6881
    Keywords: Mitochondria ; hexokinase ; normal and tumor cells ; enzyme localization ; subcellular fractionation ; receptor for binding ; monoamine oxidase ; NADPH-cytochromec reductase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Hexokinase plays an important role in normal glucose-utilizing tissues like brain and kidney, and an even more important role in highly malignant cancer cells where it is markedly overexpressed. In both cell types, normal and transformed, a significant portion of the total hexokinase activity is bound to particulate material that sediments upon differential centrifugation with the crude “mitochondrial” fraction. In the case of brain, particulate binding may constitute most of the total hexokinase activity of the cell, and in highly malignant tumor cells as much as 80 percent of the total. When a variety of techniques are rigorously applied to better define the particulate location of hexokinase within the crude “mitochondrial fraction,” a striking difference is observed between the distribution of hexokinase in normal and transformed cells. Significantly, particulate hexokinase found in rat brain, kidney, or liver consistently distributes with nonmitochondrial membrane markers whereas the particulate hexokinase of highly glycolytic hepatoma cells distributes with outer mitochondrial membrane markers. These studies indicate that within normal tissues hexokinase binds preferentially to non-mitochondrial receptor sites but upon transformation of such cells to yield poorly differentiated, highly malignant tumors, the overexpressed enzyme binds preferentially to outer mitochondrial membrane receptors. These studies, taken together with the well-known observation that, once solubilized, the particulate hexokinase from a normal tissue can bind to isolated mitochondria, are consistent with the presence in normal tissues of at least two different types of particulate receptors for hexokinase with different subcellular locations. A model which explains this unique transformation-dependent shift in the intracellular location of hexokinase is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769530
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  • 19
    Electronic Resource
    Electronic Resource
    Genetics of antagonistic action and drug resistance inLactobacillus acidophilus (1992)
    Springer
    World journal of microbiology and biotechnology 8 (1992), S. 92-97 
    Details
    ISSN: 1573-0972
    Keywords: Bacteriocin ; conjugation ; electroporation ; Lactobacillus acidophilus ; protoplast fusion ; plasmids ; transduction ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Lactobacillus acidophilus has been recommended as a dietary adjunct because of its antagonistic action toward intestinal pathogens and anti-carcinogenic and hypocholesterolemic activities. ManyL. acidophilus strains harbour plasmids and such strains generally produce bacteriocin(s). Resistance to antibiotics has also been shown to be linked with plasmids. Gene transfer and cloning systems are being developed forL. acidophilus which should permit the rapid genetic characterization of desired species and their modification to obtain predetermined traits. Drug resistance determinants and production of antibiotic-like substances may serve as suitable markers for the study and development of these genetic systems. Recent developments in gene transfer systems have been reviewed here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01195823
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  • 20
    Electronic Resource
    Electronic Resource
    Nutrient transformation in soil due to addition of organic manure and growing crops (1992)
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 313-319 
    Details
    ISSN: 1573-0867
    Keywords: Maize-mustard crop sequence ; ‘methanised’ FYM-bioslurry ; inter-relationships ; zinc fractions ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Organic matter is the major source of zinc in soil. The availability of this nutrient is dependent on the release from organic matter through mineralization and reaction with soil particles. Addition of bioslurry, containing 70 mg Zn kg−1 will influence availability of Zn through its effect on transformation reaction in soil. The present study was conducted to determine the distribution of major chemical forms of Zn in an alluvial soil, to understand the changes in zinc fractions due to bioslurry application and cropping and to find out the inter-relationships and equilibria between the fractions. Soil solution + exchangeable Zn (Zn-CA), specifically sorbed Zn by inorganic sites (Zn-ACC), specifically sorbed Zn by organic sites (Zn-PYR), Zn occluded by free oxides (Zn-OX), and residual zinc (Zn-RES) constituted 0.3, 4.5, 16.6, 16.3 and 57.3 percent, respectively of the total Zn content (Zn-TOT). Application of 13.32 t ha−1 bioslurry increased Zn content in Zn-CA, Zn-PYR and Zn-RES by 72.7, 93.2 and 36.4 percent, respectively over control. Zn occluded by free oxides (Zn-OX) was found released by the dissolution action of organic compounds present in bioslurry and the amount of Zn so released was transformed to Zn-RES, Zn-CA and Zn-DTPA. Growing crops increased Zn content in Zn-RES fraction only. Linear positive relationships between Zn-CA, Zn-PYR, Zn-RES and DTPA-Zn and bioslurry levels marked the significance of bioslurry in stabilising the status of these fractions. Path coefficient analysis and intercorrelation studies indicated the existence of equilibrium between different Zn fractions in soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01050368
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  • 21
    Electronic Resource
    Electronic Resource
    Is somaclonal variation a reliable tool for spring wheat improvement? (1992)
    Springer
    Euphytica 60 (1992), S. 221-228 
    Details
    ISSN: 1573-5060
    Keywords: agronomic performance ; somaclonal variation ; tissue culture ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seed progeny of tissue culture regenerants of a spring wheat (Triticum aestivum L. cv. HY320) was evaluated for key agronomic traits for three years under field conditions. Initially, 27 regenerant families were tested in hill plots. Among-family and within-family variation was generally highly significant (p 〈 0.01) and nonsignificant, respectively. The variation observed among regenerants on the basis of hill plot testing was not duplicated in subsequent four-row plot experiments. On average, regenerant families yielded 28 and 5% less than the control in dryland and irrigated tests, respectively. Low yielding regenerants tended to produce fewer, lighter kernels per spike. Higher grain protein levels among regenerants were associated with low yields (r=0.85). This study demonstrated that putative somaclonal variation arising from tissue culture failed to produce genotypes agronomically superior to the parental cultivar, HY 320.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039402
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  • 22
    Electronic Resource
    Electronic Resource
    Loss of resistance to Colletotrichum trifolii in in vitro regenerated alfalfa (1992)
    Springer
    Plant cell, tissue and organ culture 28 (1992), S. 207-213 
    Details
    ISSN: 1573-5044
    Keywords: anthracnose ; disease resistance ; Medicago sativa ; somaclonal variation ; tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alfalfa plants were regenerated from callus cultures of three source plants that differed in resistance to anthracnose, caused by Colletotrichum trifolii. All regenerant plants were evaluated for variation in resistance to disease caused by races 1 and 2 of the pathogen. Of eighty-two plants that were regenerated and evaluated, no plants responded differently to inoculation with race 1 of C. trifolii, but two plants (2.4%) differed in resistance when inoculated with race 2. The source plant of these regenerants was resistant to races 1 and 2 of the pathogen but the regenerants were resistant to race 1 and susceptible to race 2. No variants to race 1 were detected. The susceptible response of the variant plants to race 2 was confirmed by cytological analysis and was consistent with the response of nonregenerant susceptible plants. These plants represent a near-isogenic plant model for studying the molecular biology of resistance and susceptibility to anthracnose of alfalfa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00055519
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  • 23
    Electronic Resource
    Electronic Resource
    Survival and growth of pea protoplasts after transformation by electroporation (1992)
    Springer
    Plant cell, tissue and organ culture 30 (1992), S. 141-148 
    Details
    ISSN: 1573-5044
    Keywords: electroporation ; pea ; Pisum sativum L. ; protoplast ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protoplasts from two different pea cultivars, Belman and Filby, were stably transformed by direct gene transfer using electroporation. Transgenic calli could be obtained after selection, when hygromycin resistance was used as the selective trait introduced into the protoplasts, while no transformants were obtained when kanamycin resistance was used as selective marker in either of the two pea cultivars tested. The effect of the field strength on survival and division rates of the protoplasts was studied. Two different culture systems and osmotica were compared for induction of sustained divisions in and regeneration of transgenic callus from the protoplasts. The choice of the culture system had a considerable effect on the initial division frequency of the treated protoplasts, as well as on the later growth of the colonies. Transformation efficiency was monitored by histochemical GUS assay, and the transgenic nature of the calli selected for resistance against antibiotics was confirmed by DNA analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034308
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  • 24
    Electronic Resource
    Electronic Resource
    Somaclonal variation in winter wheat: frequency, occurrence and inheritance (1992)
    Springer
    Euphytica 64 (1992), S. 1-10 
    Details
    ISSN: 1573-5060
    Keywords: tissue culture ; somaclonal variation ; plant breeding ; Triticum aestivum ; mutation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Plants were regenerated from immature embryo cultures of 35 winter wheat genotypes. A total of 7142 R2 spike lines from 1593 R1 plants were assessed in the field for somaclonal variants of morphological traits in 1985/86, 1986/87 and 1987/88. Selected variants were studied for their possible genetic basis. Populations of R1 plants were highly variable due mainly to the physiological disturbances resulting from the in vitro processes. Overall somaclonal variation frequencies were 14.2% on the R1 plant basis and 5.3% on the R2 spike basis. Spectra of the variants were similar in the different R2 populations with predominant variants being altered negatively in plant height, maturity, awnedness, and spike and plant types. Over 90% of the variants were observed in some spike progenies of individual regenerants, while the others appeared in all spike progenies of the regenerants and in progenies of different regenerants derived from the same explant embryos. Both uniform R2 variant families and spike lines were found in addition to the segregating variants, which constituted the majority. On average, in a variant family and line, 18 and 14% of their component lines and plants varied, respectively. Inheritability was demonstrated for the variations in both segregated and uniform variant families and spike lines. Of 134 variant selections tested, about 70% was classified inhernable. Both recessive and dominant gene mutations at one, two or three loci were evident in some of the variants as suggested by segregation data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023532
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  • 25
    Electronic Resource
    Electronic Resource
    Variants of carnation (Dianthus caryophyllus L.) obtained by organogenesis from irradiated petals (1992)
    Springer
    Plant cell, tissue and organ culture 29 (1992), S. 37-42 
    Details
    ISSN: 1573-5044
    Keywords: mutagenesis ; petal culture ; regeneration ; somaclonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To obtain carnation variants differing from those produced by organogenesis alone, in vitro petal cultures were subjected to gamma irradiation. Histological analysis revealed the surface origin of buds and the different steps in meristem formation. A dose of 40 Gy administered on the fourth day of culture produced variants of horticultural interest in ‘Niky’. This period corresponded to dedifferentiation of cells that subsequently developed into bubs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00036144
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  • 26
    Electronic Resource
    Electronic Resource
    A statistical comparison of various factors on embryogenic proliferation, morphogenesis and regeneration in Lolium temulentum cell suspension colonies (1992)
    Springer
    Plant cell, tissue and organ culture 30 (1992), S. 15-29 
    Details
    ISSN: 1573-5044
    Keywords: cell suspension ; embyrogenesis ; Lolium ; regeneration ; somaclonal variation ; statistical analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell suspension colonies from four embryogenic Lolium temulentum lines were selected and plated individually in 25 embryoid maturation treatments which varied in various factors reported to stimulate embryogenesis or improve regeneration. Using a numerical scoring system to compare the cultures against a control, treatments were identified which increased growth, suppressed morphogenesis or encouraged premature shoot formation. No treatment significantly improved the proportion of colonies with globular or mature embryoids, but some prevented maturation and increased the proportion with translucent embryogenic proliferation. Other treatments accelerated maturation causing increased de-differentiation of embryogenic tissues. These treatments also tended to discourage the differentiation of discreet embryoids. Colonies were later transferred en masse to a regeneration medium and scored using another numerical system. Embryoid maturation conditions were then identified which increased or suppressed subsequent shoot regeneration. The two scoring systems enabled cultures of the four lines to be characterised in detail and identified somatic variation in embryogenic development, morphogenesis and de-differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039997
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  • 27
    Electronic Resource
    Electronic Resource
    Nonsymmetrical large deformation bending problem of circular thin plates (1992)
    Springer
    Applied mathematics and mechanics 13 (1992), S. 1149-1162 
    Details
    ISSN: 1573-2754
    Keywords: plate ; displacement ; nonlinear ; transformation ; perturbation method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract To begin with, in this paper, the displacement governing equations and the boundary conditions of nonsymmetrical large deflection problem of circular thin plates are derived. By using the transformation and the perturbation method, the nonlinear displacement equations are linearized, and the approximate boundary value problems are obtained. As an example, the nonlinear bending problem of circular thin plates subjected to comparatively complex loads is studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02456156
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  • 28
    Electronic Resource
    Electronic Resource
    A free-radical hypothesis for the instability and evolution of genotype and phenotypein vitro (1992)
    Springer
    Cytotechnology 10 (1992), S. 93-124 
    Details
    ISSN: 1573-0778
    Keywords: hybridomas ; embryonic stem cells ; immortalization ; amine oxidase ; polyamines ; cell death ; crisis ; transformation ; aneuploidy ; senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract It has been known for several decades that cultured murine cells undergo a defined series of changes, i.e., anin vitro evolution, which includes crisis, spontaneous transformation (‘immortalization’), aneuploidy, and spontaneous neoplastic transformation. These changes have been shown to be caused by thein vitro environment rather than an inherent instability of the murine phenotype or genotype. Serum amine oxidases were recently identified as a predominant cause of crisis. These enzymes generate hydrogen peroxide from polyamine substrates that enter the extracellular milieu. This finding implicates free-radical toxicity as the underlying cause ofin vitro evolution. We propose an oxyradical hypothesis to explain each of the stages ofin vitro evolution and discuss its significance for cytotechnology and long-term cultivation of mammalian cell types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570888
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  • 29
    Electronic Resource
    Electronic Resource
    Induction of stromal cell transformation in xenografts of human colonic carcinoma (1992)
    Springer
    Bulletin of experimental biology and medicine 113 (1992), S. 532-535 
    Details
    ISSN: 1573-8221
    Keywords: stromal cells ; transformation ; nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00840943
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  • 30
    Electronic Resource
    Electronic Resource
    Efficient electropulse transformation of intact Candida maltosa cells by different homologous vector plusmids (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 8 (1992), S. 691-697 
    Details
    ISSN: 0749-503X
    Keywords: Candida maltosa ; electroporation ; transformation ; plasmid vectors ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Conditions for efficient and quick transformation by electroporation were developed in Candida maltosa. To investigate the efficiency of transformation with integrative as well as with autonomously replicating plasmids, a series of vectors was constructed for homologous transformation of the species. Transformants were obtained with different plasmids as covalently closed circular molecules and as linearized DNA. The influence of recipient strain and plasmid type as well as of cell number and parameters of the supplied electrical pulse on the transformation efficiency have been investigated. A maximum of 7000 transformants per 100ng of plasmid DNA was reached. The efficiency of transformation was compared with that of the LiCl method.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320080902
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  • 31
    Electronic Resource
    Electronic Resource
    Molecular cloning and analysis of autonomous replicating sequence of Candida maltosa (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 8 (1992), S. 253-259 
    Details
    ISSN: 0749-503X
    Keywords: Candida maltosa ; automonous replicating sequence ; nucleotide sequence ; transformation ; RS15 protein ; intron ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A Candida maltosa chromosomal DNA fragment which confers high frequency transformation of C. maltosa and autonomous replication of recombinant plasmids was cloned and sequenced. Analysis of the nucleotide sequence of the cloned DNA revealed a sequence homologous for C. maltosa autonomously replicating sequence (ARS) elements. Vector pRJ1 for C. maltosa was constructed, which contained a 1.3 kb ARS sequence, pICEM-19H and the ADE1 gene of C. maltosa. Southern blot analysis suggested that the copy number of pRJ1 in C. maltosa was approximately 20 per genome. The sequence analysis also revealed an open reading frame, encoding a polypeptide with high homology (70%) to the RS15 protein of Brugia pagangi. This open reading frame has an intron with canonical sites for correct splicing in Saccharomyces cerevisiae.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320080403
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  • 32
    Electronic Resource
    Electronic Resource
    Stable and unstable transformation by microinjection of macronucleoplasm in Paramecium (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 13 (1992), S. 118-125 
    Details
    ISSN: 0192-253X
    Keywords: Microinjection ; macronucleoplasm ; transformation ; Paramecium ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Transformation by microinjection of macronucleoplasm in Paramecium caudatum was investigated. Macronucleoplasm with three genetic markers (behavior, trichocyst, and mating type) was injected into the macronucleus. To facilitate microinjection, in most cases, paramecia were immobilized in a gelatin (7.5%) solution. The injected cells began to express a dominant gene (cnrA+ or cnrB+) of the donor 9-24 hr after injection. Expression did not require cell division suggesting injected macronucleoplasm was capable of expressing a phenotype. The amount of injected macronucleoplasm appears to correlate with the frequency of successful expression but not to correlate with the time required for expression. After a number of fissions, the injected cells produced clones which had cells expressing the phenotype of the donor. This suggests that injected macronucleoplasm was replicated and expressed in the recipient cell lines. The transformed clones were classified into two groups. In one group, transformation was stable. All cell lines derived from the injected cells expressed a phenotype similar to the heterozygote of donor and recipient cells. In the other group, transformation was unstable. During the first five to seven fissions after injection, at each division, cells produced one daughter cell which later reverted to the recipient phenotype. After this unstable period, cells no longer produced the recipient phenotype but produced the donor phenotype exclusively. Donor and recipient phenotypes were, thus, segregated in different cell lines. Observation of genetic markers and analysis by computer simulation shed light on the mode of transmission of injected macronucleoplasm. In stable transformation, injected macronucleoplasm appears to be distributed equally to daughter cells. In unstable transformation, injected macronucleoplasm is distributed only to one of the daughter cells at every division until about the fifth to seventh fission after injection and then begins to assort equally to daughter cells. The cell cycle stage at injection may influence the mode of transformation. Interspecific microinjection of macronucleoplasm from P. multimicronucleatum and P. tetraurelia to P. caudatum. resulted in the expression of foreign genes in P. caudatum. In one case, injection of macronucleoplasm of P. tetraurelia produced a stable transformant indicating replication of foreign macronucleoplasm in P. caudatum. This work reveals the mode of transformation by injected macronucleoplasm and shows the possibility of transformation among Paramecium species, which is significant in the study of the conservation of gene products and the mechanism of gene expression in different species. © 1992 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020130205
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