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  • Cell & Developmental Biology  (41,698)
  • transformation
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    GeoJournal 50 (2000), S. 97-100 
    ISSN: 1572-9893
    Keywords: disease ; health ; morbidity ; mortality ; pollution ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract In general, the health of Poles improved markedly in the thirty years after the Second World War, but there was some deterioration after 1989 before improvement resumed. Only in the case of cancer is there an upward trend and so Poles are now healthier than they have been at any time in the past. However there are sharp regional variations well exemplified by the incidence of tuberculosis, where there appears to be some correlation with poorer housing and atmospheric pollution. High death rates in Lodz (consistently the highest in the country at the voivodship level between 1989 and 1996), may also be linked with environmental pollution as well as the ageing of the population. Variations between town and country are small, but Poland shows up in a poor light when compared with other European countries. These are important issues for the administration and financing of the welfare services.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    GeoJournal 52 (2000), S. 253-262 
    ISSN: 1572-9893
    Keywords: map sheets ; GIS ; seamless spatial database ; transformation ; computational procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Map sheets have been often used as a basic spatial unit for managing spatial data produced from paper maps. This often results in incompatibility between adjacent map sheets, because spatial objects do not cross the boundaries smoothly and even the boundaries themselves do not match their neighbors exactly. To solve the problem this paper proposes a computational procedure for joining separate map sheets to obtain seamless spatial data. Line objects digitized separately in different map sheets are considered, which are frequently used to represent road networks, gas pipelines, and boundaries of polygon objects. The procedure consists of three steps: (1) extraction of end nodes, (2) detection of matching nodes, and (3) transformation of the map sheet. Each step goes interactively so that unexpected errors can be avoided by human observation. To test the validity of the procedure, map sheets are combined containing the road network data of Tokyo 23-ku area, Japan.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    GeoJournal 50 (2000), S. 151-155 
    ISSN: 1572-9893
    Keywords: demography ; experts ; rural ; Romania ; rural development ; social issues ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract There is no standard model of transformation for post- socialist countries and each country encounters specific problems rooted in the geographical characteristics of the areas concerned. The human resources are of the greatest importance because it really matters how people (especially the decision-makers) perceive system change and continually reformulate their expectations and strategies; so investigations into the views of people caught up in the transformation can provide a deeper understanding of the background to structural change. Working the national, regional level and local levels in Romania, experts were asked to consider the advantages and disadvantages arising out of the transformation, the most important problems and constraints for future rural development and the policies needed. The paper examines the responses on demographic and social issues. It emerges the most detailed responses were supplied by local-level representatives while respondents at the regional level steered a middle course between the need to address local problems and the prime importance of stimulating the Romanian economy so as to generate resources for welfare programmes (with the latter issue the overriding concern of interviewees at national level). There was general agreement on the importance of foreign investment and European integration for economic development, with local actors taking only small steps in line with the existing opportunities.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Chemistry of natural compounds 36 (2000), S. 137-139 
    ISSN: 1573-8388
    Keywords: 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid ; transformation ; DMSO
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Transformations of 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid (batridene) in DMSO are studied.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 177-182 
    ISSN: 1573-0972
    Keywords: Conjugation ; metal resistance ; plasmid DNA ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Heavy metal concentrations in soil treated with industrial wastewater of Aligarh City (U.P.), India were determined. The analysis of test samples revealed high levels of Fe, Zn, Ni and Cu. A total of 45 Pseudomonas spp. were isolated from soil and were characterized on the basis of morphological, cultural and biochemical characteristics. MICs of Hg2+, Cd2+, Cu2+, Cr3+, and Zn2+ for each isolate were determined. Eighty percent of the strains isolated from soil harboured resistance to copper, whereas 73.3% of the isolates exhibited resistance to cadmium, 71.1% to chromium and zinc and 48.8% to mercury. A maximum MIC of 200 μg/ml for mercury and 1600 μg/ml for other metals was observed. Metal resistance was found to be plasmid mediated as evidenced by transformation studies. Further, the transmissible nature of chromium resistance was confirmed by conjugation. Agarose gel electrophoresis using the miniprep method for plasmid isolation revealed that these isolates harboured plasmids of molecular weights (45 & 47 kb) using EcoRI and HindIII digests of λDNA and undigested λDNA as standard markers.
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  • 6
    ISSN: 1573-5060
    Keywords: Barley ; Hordeum vulgare ; transformation ; particle bombardment ; particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Immature embryos of the spring barley variety GoldenPromise, were bombarded with three different particledelivery systems and both transient and stabletransformation examined. In addition, a range oftechniques for the preparation of the DNA coated goldparticles was examined. Fertile transgenic barleyplants were obtained using three particle preparationtechniques which differed in the amount of gold andDNA used for each bombardment. However, only one ofthe particle delivery systems, the PDS 1000/He device,appeared to be effective in yielding transformedbarley plants.
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  • 7
    ISSN: 1573-5060
    Keywords: cell suspension ; monocotyledon ; selection ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The successful application of plant biotechnology to Alstroemeria improvement will largely depend on the availability of an efficient regeneration/transformation system. Regeneration in Alstroemeria is accomplished from nodular embryogenic callus initiated from zygotic embryos. Histological studies of embryogenic callus initiation from 4-weeks old cultured ovules revealed that the outermost layers of the protoderm of the embryogenic nodules divided to form either a new nodule or aproembryo. Transient gene expression after particle bombardment of nodular embryogenic callus was optimized using DNA of pAHC25. The highest β-glucuronidase expression was found when the GUS gene was under control of the maize ubiquitin promoter, the target tissue was placed 5 cm below the microcarrier launch assembly and when the rupture disc-breakage point was between 650–900 psi. Kanamycin blocked regeneration of somatic embryos, however, did not block growth of nodular embryogenic callus. With phosphinothricin both callus growth and regeneration were blocked. Bombardment of nodular embryogenic callus with DNA of pAHC25 combined with selection on medium containing phosphinothricin resulted in putative transgenic chimeric. Friable calli were selected from nodular embryogenic callus and used to initiate suspensions. These cell suspensions were subjected to transformation by particle bombardment using DNA of pAHC25 and resulted in a stable transformed friable callus line after selection based on luciferase activity. Even after 2 years of maintenance this callus line was luciferase positive and the Polymerase Chain Reaction analysis demonstrated the presence of the introduced gene in this friable callus line.
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  • 8
    ISSN: 1573-5087
    Keywords: alfalfa ; cell division cycle ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two simple, rapid and efficient protocols for theregeneration of transformed tetraploid lines ofalfalfa (Medicago falcata L.) have beendeveloped and compared. Leaf explants fromembryogenic lines 47/1-150 and 47/1-5 were inoculatedwith Agrobacterium tumefaciens containingconstructs carrying the nptII selectable markergene and promoter:gusA gene fusions under thecontrol of the CaMV 35S or Arabidopsis cdc2a,CycB1 and CycA2 promoters. In the firstregeneration system (the MSH system), inoculated leafexplants were incubated on MS medium supplemented with2,4-D and kinetin and then subcultured onto plantgrowth regulator-free MS medium in order to inducedirect somatic embryogenesis. In the secondregeneration system (the B5h system), the inoculatedexplants were incubated on B5h medium to induceindirect production of somatic embryos viaembryogenic callus. In both systems, an effectivekanamycin selection regime was employed and wasmaintained when the embryos were subcultured onto arecovery medium (Boi2Y) to promote further embryodevelopment. The use of Boi2Y medium was particularlyimportant for shortening the regeneration time andpromoting a higher frequency of healthy plantletproduction from the somatic embryos. The maturesomatic embryos were finally transferred to plantgrowth regulator-free MS medium for plantletformation. Transgenic plantlets were produced within10–14 weeks in the MSH system and 12–16 weeks in theB5h system. The MSH system appears to be the fastesttransformation system reported for leguminous speciesto date. Confirmation of transformation was obtainedusing a re-callusing assay on kanamycin and subsequentSouthern blot hybridisation and PCR analysis. Theability to induce expression of GUS activity in leafexplants containing the cell division cycle genepromoter:gusA constructs by 2,4-D treatment alsoproved to be a reliable indicator of transformation.
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  • 9
    ISSN: 1573-4889
    Keywords: Fe–Cr–Al alloy ; oxidation ; molybdenum ; breakaway oxidation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thin foils of Fe–20Cr–5Al alloys are susceptible to breakawayoxidation once the aluminum content of the substrate has fallen below somecritical value. The combined addition of 0.1 wt.% lanthanum and 0, 1, or 2wt% molybdenum has a beneficial effect on the high-temperature oxidation ofsuch foils. Lanthanum has the well-known reactive-element effect on adhesionof the protective alumina scale, thereby increasing the time to onset ofbreakaway oxidation, while, for alloys containing molybdenum, breakawayoxide spreads relatively slowly over the specimen in comparison to alloysthat contain no molybdenum. In particular, molybdenum-containing alloys areable to develop a protective Cr2O3 layer at the breakawayoxide–substrate interface. Conversely, molybdenum-free alloys form aninternal-oxide zone in the substrate adjacent to this interface, rather thana Cr2O3 layer, so breakaway oxide spreads rapidly. A martensitic phase isobserved in the substrate adjacent to the breakaway oxide formed on Fe–20Cr–5Al–La specimens, which means that theα-phase has transferred to the γ -phase at the temperature ofthe oxidation test (1150°C). Conversely, α-phase is retained inthe molybdenum-containing alloy, even after breakaway takes place, sincemolybdenum, which is a strong ferrite former, is enriched in the alloyadjacent to areas of breakaway oxide. The diffusion rate of chromium isslower in the γ than in the α-phase so a continuouschromium-rich oxide layer, which is effective in inhibiting breakawayoxide from spreading, cannot be established at the breakawayoxide–substrate interface for the molybdenum-free alloys.
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  • 10
    ISSN: 1573-5060
    Keywords: conifers ; salgareño pine ; tissue culture ; transformation ; transient gene expression ; uidA expression ; vir gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cotyledons from dissected sterile embryos of salgareño pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) were inoculated with different disarmed Agrobacterium tumefaciens strains harbouring the binary vector p35SGUSint. The transient expression of a β-glucuronidase gene (uidA) was studied, using a histochemical staining procedure. Nineteen days after inoculation, the activity of β-glucuronidase was detected in epidermal and subepidermal layers of cotyledonary explants. The EHA105 strain harbouring a disarmed agropine-type Ti-plasmid (pTiBO542) was the most effective for gene transfer of the uidA gene. The effects of exudates and extracts from 0-day-old embryos on induction of vir gene expression in A. tumefaciens were also examined. The results of this study showed that salgarño pine embryo exudates contain a substance(s) that induce vir gene expression, in similar way to that observed with 100 μM acetosyringone (AS).All these findings suggest that T-DNA processing and transfer might take place when Agrobacterium infects suitable tissues of salgareño pine.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Pituitary 3 (2000), S. 117-122 
    ISSN: 1573-7403
    Keywords: Cushing's disease ; silent ; pituitary ; tumour ; macroadenoma ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Silent pituitary adenomas occur in 25–40% of all clinically apparent pituitary tumours. However, the subsequent development of florid Cushing's disease in a patient with a previous non-functioning tumour is extremely rare. We describe a 47 year-old woman presenting initially with a large, invasive and recurrent, non-functioning pituitary tumour. Histopathologic study of the initial tissue did not stain for any hormones. Six years after the initial presentation, she manifested florid ACTH dependent Cushing's syndrome. A recurrent invasive pituitary macroadenoma necessitated a third transphenoidal surgery. The resected specimen, in this instance, revealed positive staining for ACTH, FSH, prolactin, and growth hormone on immunocytochemistry. An incomplete response to surgical, radiation and medical therapy necessitated a bilateral adrenalectomy to control the hypercortisolism, which resulted in remarkable clinical improvement. We also review five previous case reports from the revision literature of similar transformations from non-secreting pituitary adenomas to Cushing's disease. This subset of patients may represent yet another entity in the widening spectrum of Cushing's syndrome.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Transgenic research 9 (2000), S. 471-486 
    ISSN: 1573-9368
    Keywords: Arabidopsis thaliana ; Agrobacterium tumefaciens ; floral spray ; SOD ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study, floral spray and floral dip were used to replace the vacuum step in the Agrobacterium-mediated transformation of a superoxide dismutase (SOD) gene into Arabidopsis. The transgene was constructed by using a CaMV 35S promoter to drive a rice cytosolic CuZnSOD coding sequence in Arabidopsis. The transgene construct was developed in binary vectors and mobilized into Agrobacterium. When Arabidopsis plants started to initiate flower buds, the primary inflorescence shoots were removed and then transformed by floral spray or floral dip. More than 300 transgenic plants were generated to assess the feasibility of floral spray used in the in planta transformation. The result indicates that the floral spray method of Agrobacterium can achieve rates of in planta transformation comparable to the vacuum-infiltration and floral dip methods. The floral spray method opens up the possibility of in planta transformation of plant species which are too large for dipping or vacuum infiltration.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Transgenic research 9 (2000), S. 405-415 
    ISSN: 1573-9368
    Keywords: Manihot esculenta ; transformation ; Agrobacterium tumefaciens ; mannose ; hygromycin ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to improve the efficiency of cassava (Manihot esculenta Crantz) transformation, two different selection systems were assessed, a positive one based on the use of mannose as the selective agent, and a negative one based on hygromycin resistance encoded by an intron-containing hph gene. Transgenic plants selected on mannose or hygromycin were regenerated for the first time from embryogenic suspensions cocultivated with Agrobacterium. After the initial selection using mannose and hygromycin, 82.6% and 100% of the respective developing embryogenic callus lines were transgenic. A system allowing plant regeneration from only transgenic lines was designed by combining chemical selection with histochemical GUS assays. In total, 12 morphologically normal transgenic plant lines were produced, five using mannose and seven using hygromycin. The stable integration of the transgenes into the nuclear genome was verified using PCR and Southern analysis. RT-PCR and northern analyses confirmed the transgene expression in the regenerated plants. A rooting test on mannose containing medium was developed as an alternative to GUS assays in order to eliminate escapes from the positive selection system. Our results show that transgenic cassava plants can be obtained by using either antibiotic resistance genes that are not expressed in the micro-organisms or an antibiotic-free positive selection system.
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  • 14
    Electronic Resource
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    Springer
    Applied mathematics and mechanics 21 (2000), S. 1423-1431 
    ISSN: 1573-2754
    Keywords: nonlinear differential equations ; transformation ; algorithm ; analytical solution ; O175.29
    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 The idea of AC=BD was applied to solve the nonlinear differential equations. Suppose that Au=0 is a given equation to be solved and Dv=0 is an equation to be easily solved. If the transformation u=Cv is obtained so that v satisfies Dv=0, then the solutions for Au=0 can be found. In order to illustrate this approach, several examples about the transformation C are given.
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  • 15
    ISSN: 1573-9368
    Keywords: inheritance ; Rubisco small subunit promoters ; sonication ; sulphur nutrition ; sunflower albumin ; transformation ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract With the aim of increasing the rumen-protected level of the sulphur amino acids cysteine and methionine in Trifolium repens, we introduced the coding sequence of the sunflower seed albumin (SSA) into T. repens by Agrobacterium tumefaciens-mediated transformation. The SSA gene was modified such that the protein would be localised to the endoplasmic reticulum (ER). Four different T-DNA constructions all containing the SSA gene driven by either the promoter of a gene encoding the small subunit of ribulose bisphosphate carboxylase (Rubisco) from Arabidopsis thaliana (A ssu), the promoter of the gene encoding the small subunit of Rubisco of Medicago sativa (L ssu), or the Cauliflower Mosaic Virus 35S promoter (CaMV35S), were transferred to T. repens cv. Haifa. Transgenic T 0-plants and inter-transgenic hybrids were analysed for the level of SSA accumulation in the leaves by western blotting. The highest observed level of SSA accumulation was 0.1% of total extractable leaf protein. We observed that the promoter had a substantive effect on the level of SSA accumulation with A ssu〉CaMV35S〉L ssu. Results from the inter-transgenic hybrids showed that the capacity to synthesise SSA was inherited. However the level of SSA accumulation in the leaves generally appears not to be additive with extra transgenic loci. During this work, we attempted to improve the efficiency of A. tumefaciens-mediated transformation of T. repens using the SAAT-method (Sonication Assisted Agrobacterium-mediated Transformation) on cotyledons of T. repens. T-DNA transfer was in general not enhanced by sonication compared to traditional A. tumefaciens-mediated transformation. Furthermore, Southern blot analyses of plants regenerated from the same cotyledon after A. tumefaciens treatment and under selection, indicated that multiple shoots were usually derived from the same transformation event. We concluded from these results that only one plant from each A. tumefaciens-treated cotyledon should be taken to avoid transgenic clones.
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  • 16
    ISSN: 1573-9368
    Keywords: Hyoscyamus muticus ; particle bombardment ; transformation ; tropane alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report an efficient whole plant transformation system for Hyoscyamus muticus, an important medicinal plant of the Solanaceous family. We developed a system using a plasmid carrying the nptII and gusA genes, which was delivered into leaf explants by particle bombardment. Ten percent of bombarded leaf explants formed kanamycin-resistant callus, from which putative transgenic plants were recovered. The nptII gene conferring kanamycin resistance was found to be incorporated into the genome of all transgenic plants screened. Over 50% of the kanamycin resistant plants showed strong expression of the non-selected gusA gene. The majority of transgenic plants reached maturity, could be self pollinated, and produced fertile seed. A simple and efficient whole plant transformation system for this medicinal plant is an important step in furthering our understanding of tropane alkaloid production in plants.
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  • 17
    ISSN: 1573-6776
    Keywords: casein hydrolysate ; Coleus forskohlii ; forskolin ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Casein hydrolysate at 2.0 g l−1 significantly enhanced forskolin content (2.3 mg g−1 cell dry wt) in a rhizogenic tumourous line, GCO-RCH-2 of Coleus forskohlii. In rooty teratoma line, RC-ST-2/4, forskolin content enhanced to 1.7 mg g−1 cell dry wt in presence of 2.5 g l−1 casein hydrolysate. Unlike untransformed calli and rhizogenic/root cultures, all the forskolin yielding transformed cultures of C. forskohlii have been maintained for over 5 years.
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  • 18
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; sorghum ; transformation ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a `Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.
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  • 19
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    Springer
    Journal of applied psychoanalytic studies 2 (2000), S. 109-115 
    ISSN: 1573-3459
    Keywords: James Joyce ; “The Dead” ; fiction ; reading ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract The author offers a personal reading of James Joyce's “The Dead.” She focuses on how the sounds of the language are used to portray the main character's deadness and his beginning to come to life once the barriers to inner self and self-knowledge are broken.
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  • 20
    ISSN: 1573-4986
    Keywords: Cancer ; caveolae ; caveolin ; cholesterol ; glucosylceramide ; multidrug resistance ; rafts ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The carcinogenic process involves a complex series of genetic and biochemical changes that enables transformed cells to proliferate, migrate to secondary sites and, in some cases, acquire mechanisms that make cancer cells resistant to chemotherapy. This phenomenon in its most common form is known as multidrug resistance (MDR). It is usually mediated by overexpression of P-glycoprotein (P-gp) or other plasma membrane ATPases that export cytotoxic drugs used in chemotherapy, thereby reducing their efficacy. However, additional adaptive changes are likely to be required in order to confer a full MDR phenotype. Recent studies have shown that acquisition of MDR is accompanied by up-regulation of lipids and proteins that constitute lipid rafts and caveolar membranes, notably glucosylceramide and caveolin. These changes may be related to the fact that in MDR cells a significant fraction of cellular P-gp is associated with caveolin-rich membrane domains, they may be involved in drug transport and they could have an impact on drug-induced apoptosis and on the phenotypic transformation of MDR cancer cells.
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  • 21
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    Molecular breeding 6 (2000), S. 185-194 
    ISSN: 1572-9788
    Keywords: Agrobacterium ; transformation ; pea ; Pisum sativum L. ; PCR analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Factors influencing the efficiency of Agrobacterium-mediated transformation of pea were tested using highly efficient, direct regeneration system. The virulence of three Agrobacterium strains (octopine LBA 4404, nopaline C58C1 and succinamopine, hypervirulent EHA 105) clearly varied giving 1 transgenic plant per 100 explants for LBA 4404, 2.2 for C58C1 and 8.2 for EHA 105. To test the efficacy of selection agents we used the hypervirulent EHA 105 strain carrying pGPTV binary vector with one of four different selection genes: nptII, hpt, dhfr or bar. The mean number of transgenic, kanamycin-resistant plants for two cultivars tested was 4.2 per 100 explants and was slightly higher than the number of phosphinothricin-resistant plants (3.6 plants per 100 explants). The proportion of transgenics among kanamycin-selected plants was also higher than among phosphinothricin-resistant plants (35% and 28% respectively). There was no regeneration on hygromycin or methotrexate media (transformation with hpt and dhfr genes). Acetosyringone had no apparent influence on efficiency of transformation with hypervirulent EHA 105 strain, however it did affect the rate of transformation when moderately virulent C58C1 was used. Recovery of transgenic plants was enhanced after application of 5-azacytidine. The presence of integrated T-DNA was checked by PCR and confirmed by Southern hybridization. T-DNA was stably transmitted to the next generation.
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  • 22
    ISSN: 1572-9788
    Keywords: antisense DNA ; co-transformation ; nucleocapsid gene ; pathogen-derived resistance ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Peanut (Arachis hypogaea L.) lines transgenic for the antisense nucleocapsid (N) gene of a Tomato spotted wilt virus (TSWV) strain isolated from peanut were generated by microprojectile-mediated transformation of repetitive somatic embryos of cultivars VC1 and AT120. The selectable marker (hygromycin resistance) and the N gene were on separate plasmids. A total of 207 VC1 and 120 AT120 hygromycin-resistant lines were produced. Of all the VC1 plants recovered 71% were cotransformed with the N gene (N+), but all plants were sterile. For AT120, 48 of the transgenic cell lines converted into plants. Polymerase chain reaction (PCR) screening showed 15 of the lines were transgenic for the N gene (N+), and two of these lines were fertile. A field test was conducted in 1998 at Ashburn, GA, using seeds from each fertile line, along with segregated and non-transgenic controls. Plants from four randomly selected field plots were examined for symptoms and analyzed by double-antibody sandwich enzyme-linked immunoabsorbent assay and PCR at 10 and 14 weeks after planting. At 14 weeks, 76% of the N+ plants were symptomless, while 2% were severely symptomatic or dead. In contrast, only 42% of the plants lacking the N gene were symptomless and 50% were severely symptomatic or dead. Northern blot analysis of selected field-resistant plants detected transgene RNA, and the transcript level appeared undiminished after viral exposure.
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  • 23
    ISSN: 1572-9788
    Keywords: bar ; cry3A ; Eucalyptus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transgenic Eucalyptus camaldulensis containing both the insecticidal cry3A gene and the bar gene (conferring tolerance to the herbicide glufosinate ammonium) have been produced by Agrobacterium tumefaciens-mediated transformation of seedling explants. Transgenic plants from two lines tested were resistant to first instars of chrysomelid beetles that are important pests of commercial Australian eucalypt plantations. Both lines also exhibit tolerance to the broad-spectrum herbicide Liberty® at 6 l/ha (1.2 kg active ingredient per hectare), twice the field application rate. Transgenic insect- and herbicide-resistant eucalypts like these are likely to provide better insect and weed control options in plantations, particularly during the vulnerable establishment phase, provided that any adverse ecological impacts of releasing transgenic trees into the environment can be assessed and minimized.
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  • 24
    ISSN: 1572-9788
    Keywords: choline oxidase ; glycinebetaine ; Japanese persimmon ; salt tolerance ; transformation ; woody plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This report describes the first successful genetic engineering of tolerance to salt in an agriculturally important species of woody plants by Agrobacterium-mediated transformation with the codA gene of Arthrobacter globiformis. This gene encodes choline oxidase, which catalyzes the oxidation of choline to glycinebetaine. The binary plasmid vector pGC95.091, containing a kanamycin-resistance gene (nptII), a gene for β-glucuronidase (gusA) and the codA gene in its T-DNA region, was used with a disarmed strain of Agrobacterium tumefaciens, EHA101, to transform Japanese persimmon (Diospyros kaki Thunb. `Jiro') by the leaf disk transformation method. The pRS95.101 plasmid that included only nptII and gusA in the T-DNA region was used as a control. We selected eight transgenic lines with one or two copies of the T-DNA after transformation with pGC95.091 (PC lines) and three lines after transformation with pRS95.101 (PR lines). The eight PC lines produced choline oxidase and glycinebetaine whereas neither was found in untransformed `Jiro' and in the control PR lines. Transgenic plants grew normally, resembling wild-type plants both in vitro and ex vitro. The activity of photosystem II in leaves of the transgenic Japanese persimmon plants under NaCl stress was determined in terms of the ratio of the variable (F v) to the maximum (F m) fluorescence of chlorophyll (F v/F m). The rate of decline in (F v/F m under NaCl stress was lower in the PC lines than in the control PR lines. These results demonstrated that genetic engineering of Japanese persimmon, which allowed it to accumulate glycinebetaine, enhanced the tolerance to salt stress of this plant.
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  • 25
    ISSN: 1572-9788
    Keywords: heterologous protein accumulation ; phytate phosphorus digestibility ; phytase ; phytic acid ; transformation ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Aspergillus niger phytase-encoding gene (phyA) has been constitutively expressed in wheat. Transgenic wheat lines were generated by microprojectile bombardment of immature embryos, using the bar-Bialaphos selection system. The bar and the phyA gene expression were controlled by the maize ubiquitin-1 promoter. To ensure secretion and glycosylation of the microbial phytase, an expression cassette was designed (Ubi-SP-Phy) where an α-amylase signal peptide sequence was inserted between the promoter and the phytase coding region. A similar cassette was constructed without the signal peptide sequence (Ubi-Phy). Five lines of fertile wheat transformed with the Ubi-SP-Phy were generated and two lines with the Ubi-Phy construct. The inheritance of the phyA gene was monitored through three generations. Western blotting of leaf and seed derived protein revealed the presence of an immunoreacting polypeptide of the size expected for the Aspergillus phytase. Up to 25 days after pollination, the heterologous phytase was exclusively present in the pericarp-seed coat-aleurone fraction. Thereafter, it accumulated in the endosperm in amounts exceeding that found in the seed coat and aleurone. The phyA mRNA and derived protein could at no stage be detected in the embryo. The Ubi-SP-Phy transgenic seeds exhibited up to 4-fold increase of phytase activity while up to 56% increase was found in Ubi-Phy plants. It is concluded that a functional Aspergillus phytase can be produced in significant amounts in wheat grains. This may be of relevance for improving the phytate-phosphorus digestibility when wheat grains are used for non-ruminant animal feed.
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  • 26
    ISSN: 1572-9788
    Keywords: Choline oxidase ; glycinebetaine ; transformation ; Brassica juncea ; salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The codA gene for biosynthesis of glycinebetaine from Arthrobacter globiformis was used for transforming Brassica juncea cv. Pusa Jaikisan (which lack any means to synthesize glycinebetaine) through Agrobacterium mediated transformation. The stable insertion of the codA gene in the shoots obtained on medium with kanamycin and hygromycin was confirmed by PCR analysis of the nptII gene. Southern hybridization with a codA probe further demonstrated its successful integration. Immunoblot analysis revealed the presence of choline oxidase demonstrating that the bacterial codA gene had been successfully transcribed and translated. The seeds of transgenic lines showed enhanced capacity to germinate under salt stress as compared to that of the wild type. Further, the seedlings of transgenic plants that expressed codA gene showed significantly higher growth than that of the wild type under salt stress conditions. These results demonstrated that the introduction of a biosynthetic pathway for glycinebetaine into Brassica juncea significantly enhanced their salt tolerance. Hence, homozygous genotypes of selected transformed lines can be exploited for improving the salt tolerance of the desirable cultivars of Brassica juncea through breeding programmes.
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  • 27
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    Systemic practice and action research 13 (2000), S. 475-501 
    ISSN: 1573-9295
    Keywords: reflection ; transformation ; self-society dynamics ; critical systems thinking ; systemic intervention ; critical self-reflection ; ideology-critique ; critical appreciation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology
    Notes: Abstract This paper sets out to uncover some relationships between reflection, discourse and action. By challenging and synthesizing some polemical arguments concerning the creation, maintenance, and transformation of self and society, a model of self-society dynamics that operates through reflection, discourse, and action is developed. The model of self-society dynamics brings together aspects of self-reflection and ideology-critique (explored in the paper), which it is suggested are required for any intervention (transformative action) to be grounded in locally meaningful ways. By creating a dialog community in which self- and group assumptions can be subjected to validation through discourse, it is proposed that a dynamic balance between individual needs and broader societal aims may be achieved. If individuals can be open to such discourse (i.e., they can become critically self-reflective), then it is argued that possibilities for achieving sustainable change will be significantly enhanced.
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  • 28
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    Journal of thermal analysis and calorimetry 56 (1999), S. 1133-1140 
    ISSN: 1572-8943
    Keywords: branched diamine ; melting ; polyamides ; polymorphism ; transformation ; WXRD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Our X-ray work of Dytek®-A, 2-methyl-pentamethylenediamine, containing polyamides shows polymorphism, whereas the polyamides with linear diamines do not. The polyamide of Dytek®-A and dodecanedioic acid, MPMD-12, is singled out for discussion and compared with the unbranched analogs of polyamides 6,12 and 5,12. Due to the presence of the -CH3 side group in the 2-position of the diamine, the polyamide MPMD-12 exhibits two stable crystal conformations. The new δ polymorph is not seen in linear polyamides 6,12 and 5,12. Studies by DSC polyamide MPMD-12 clearly illustrates at least two crystal forms, γ and δ, coexisting over a wide temperature range, and the isolation of each phase is possible by controlling temperature and time. The DMA modulus in the temperature region between the glass transition (or alpha relaxation) and melting transition shows strong dependence on the thermal history as demonstrated in a study of crystallization kinetics.
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  • 29
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    Plant molecular biology reporter 17 (1999), S. 323-331 
    ISSN: 1572-9818
    Keywords: Agrobacterium ; modular vector ; transformation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
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  • 30
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    GeoJournal 49 (1999), S. 43-51 
    ISSN: 1572-9893
    Keywords: housing market ; suburbanisation ; transformation ; urban development ; urban renewal ; East Germany
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract The aim of this paper is to analyse the main characteristics of post-socialist urban development in East Germany, especially the differences compared to urban development in other East and Central European countries. In spite of the many similar problems and processes in urban development, specific features of East Germany are characterised by the rapid growth of suburbia, especially in the first phase of transition, by the proceeding activities of urban renewal and revitalisation, and by a lower level of social polarisation and socio-spatial segregation as compared to other post-socialist countries. Important conditions for urban development in East Germany exist in special support programmes, high subsidies and other financial transfers as well as in engaged planning conceptions of the local authorities.
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  • 31
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    Cancer and metastasis reviews 18 (1999), S. 215-230 
    ISSN: 1573-7233
    Keywords: transformation ; tumour ; Frizzled ; Dishevelled ; glycogen synthase kinase-3β
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Wnt signalling is involved in a variety of mammalian developmental processes, including cell proliferation, differentiation and epithelial–mesenchymal interactions, through which they contribute to the development of tissues and organs such as the limbs, the brain, the reproductive tract and the kidney. Wnts are secreted ligands that control cell processes via at least two pathways, one of which, the ‘canonical’ Wnt signalling pathway, operates through the cytosolic stabilisation of a transcriptional co-factor, β-catenin. This is achieved by downregulating the activity of a β-catenin turnover complex. Evidence from tumour expression studies, transgenic animals and in vitro experiments suggests that inappropriate activation of the canonical Wnt signalling pathway is a major feature in human neoplasia and that oncogenic activation of this pathway can occur at many levels. Inappropriate expression of the Wnt ligand and Wnt binding proteins have been found in a variety of human tumours. Further downstream, dysregulation of the β-catenin turnover complex, by loss of the Adenomatous Polyposis Coli or Protein Phosphatase 2A proteins, or by activating mutations of β-catenin, has been found in several tumour types, and is believed to be a key step in neoplastic progression. Transcriptional targets of the Wnt pathway include the cellular oncogenes cyclin D1 and c-myc. Activation of the Wnt signalling pathway by various means can therefore be a primary cause in oncogenesis, affecting cell proliferation, morphology and contact inhibition, as well as co-operating with other oncogenes in multistep tumour progression.
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  • 32
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    European journal of plant pathology 105 (1999), S. 221-229 
    ISSN: 1573-8469
    Keywords: mutagenesis ; transformation ; plant disease ; recombination ; plant pathogenic fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Development of molecular techniques for phytopathogenic fungi aims at the identification of fungal genes whose products are essential for successful infection of the host plant. Initial approaches have relied on isolating candidate genes and generating null-mutations by homologous recombination. Unfortunately, the results of this strategy have not been overly successful. This has led to a search for alternatives which allow an unbiased identification of pathogenicity genes. One method, which has proved successful in several systems, is a tagging mutagenesis procedure termed restriction enzyme mediated integration (REMI). In this mini-review we describe this procedure and review its features and results of its use when applied to the identification of fungal genes required for disease development in planta.
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  • 33
    ISSN: 1572-9729
    Keywords: abiotic ; biological ; cell-free extract ; chloroethane ; dechlorination ; 1,1-dichloroethane ; 1,1-dichloroethene ; digester ; methanogenic ; transformation ; 1,1,1-trichloroethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Anaerobic transformations of 1,1,1-trichloroethane (TCA), 1,1-dichloroethane (DCA), and chloroethane (CA) were studied with sludge from a lab-scale, municipal wastewater sludge digester. TCA was biologically transformed to DCA and CA and further to ethane by reductive dechlorination. TCA was also converted to acetic acid and 1,1-dichloroethene (11DCE) by cell-free extract. 11DCE was further biologically converted to ethene. This pathway was confirmed by transformation tests of TCA, DCA and CA, by tests with cell-free extract, and by chloride release during TCA degradation. With cell-free extract, acetic acid accounted for approximately 90% of the TCA transformed; tests with live cells indicate that the fraction of TCA transformed by this pathway decreased with lower biomass. The dechlorination of DCA to CA and CA to ethane was not stoichiometric. A high rate of TCA removal was observed under the experimental conditions. The results indicate that removal of TCA in anaerobic digestion should be complete, but DCA and CA could persist in a normally operating digester.
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  • 34
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    World journal of microbiology and biotechnology 15 (1999), S. 411-415 
    ISSN: 1573-0972
    Keywords: Electroporation ; Micrococcus species ; steroid biotransformation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A steroid-biotransforming strain RJ6 was identified as Micrococcus roseus. This bacterium has a 10 kb plasmid pMQV10. Curing mediated through cultivation of the culture with a low concentration (200 ng/ml) of mitomycin C is described. Loss of cholesterol degradation (chol+) and streptomycin resistance (Smr) phenotypes as a consequence of the loss of plasmid indicate the extrachromosomal location of these two genes in this strain. An electroporation procedure was developed for transformation of cured strain of Micrococcus (RJC6) by plasmids. Frequency of greater than 105 transformants/μg DNA was achieved, which is 100-fold higher than the standard transformation procedure that yielded 5.3×103 transformants/μg DNA in the same strain.
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  • 35
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    World journal of microbiology and biotechnology 15 (1999), S. 1-6 
    ISSN: 1573-0972
    Keywords: Bacteria ; conjugation ; DNA ; evolution ; gene transfer ; transduction ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The transfer of genetic information by transformation, conjugation and transduction in bacteria occurs frequently in nature. These diverse gene transfer mechanisms in bacteria are the result of evolution and are not linked to reproduction as in eukaryotic organisms. In this review, gene transfer in bacteria will be considered from an evolutionary perspective.
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  • 36
    ISSN: 1573-5028
    Keywords: conditional lethal dominant gene ; Cre/loxP ; Nicotiana tabacum ; site-specific recombinase ; transformation ; transient expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic tobacco plants were produced that contained single-copy pART54 T-DNA, with a 35S-uidA gene linked to loxP-flanked kanamycin resistance (nptII) and cytosine deaminase (codA) genes. Retransformation of these plants with pCre1 (containing 35S transcribed cre recombinase and hygromycin (hpt) resistance genes) resulted in excision of the loxP-flanked genes from the genome. Phenotypes of progeny from selfed-retransformed plants confirmed nptII and codA excision and integration of the cre-linked hpt gene. To avoid integration of the hpt gene, and thereby generate plants totally free of marker genes, we attempted to transiently express the cre recombinase. Agrobacterium tumefaciens (pCre1) was cocultivated with leaf discs of two pART54-transformed lines and shoots were regenerated in the absence of hygromycin selection. Nineteen of 773 (0.25%) shoots showed tolerance to 5-fluorocytosine (5-fc) which is converted to the toxic 5-fluorouracil by cytosine deaminase. 5-fc tolerance in six shoots was found to be due to excision of the loxP-flanked region of the pART54 T-DNA. In four of these shoots excision could be attributed to cre expression from integrated pCre1 T-DNA, whereas in two shoots excision appeared to be a consequence of transient cre expression from pCre1 T-DNA molecules which had been transferred to the plant cells but not integrated into the genome. The absence of selectable marker genes was confirmed by the phenotype of the T1 progeny. Therefore, through transient cre expression, marker-free transgenic plants were produced without sexual crossing. This approach could be applicable to the elimination of marker genes from transgenic crops which must be vegetatively propagated to maintain their elite genotype.
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  • 37
    ISSN: 1573-5044
    Keywords: ß-glucuronidase ; dendrobium ; hygromycin phosphotransferase ; orchid ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protocorms of orchid (Dendrobium hybrid) were transformed by microprojectile bombardment with a helium-pressured PDS 1000 particle gun. Gold particles coated with plasmid DNA containing ß-glucuronidase (GUS) and hygromycin phosphotransferase (Hpt) marker genes were used. Potentially transformed tissues were identified by active growth on MS medium supplemented with 50mg l-1 hygromycin. After 4–6 months of continuous selection, 15 hygromycin-resistant lines were recovered. Integration of transgenes into the genome of the transformed protocorms and plantlets were confirmed by GUS histochemical assay and Southern blot hybridization. The transgenic protocorms have gone through propagation for more than 8 months and maintained their transgenic characters. These results indicate that we have established a system for orchid transformation in a relatively high frequency and the transgenes are stably expressed in the transgenic plants.
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  • 38
    ISSN: 1573-5079
    Keywords: Chlamydomonas reinhardtii ; LHC II phosphorylation ; mutagenesis ; Photosystem II redox control ; state 2 to state 1 transition ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygenic photosynthetic organisms adapt to varying light conditions by changing the distribution of light energy between Photosystem II (PS II) and photosystem I (PS I) during so-called state transitions. To identify the genes involved in this process, we have exploited a simple chlorophyll fluorescence video-imaging technique to screen a library of nuclear mutants of Chlamydomonas reinhardtii for colonies grown on agar plates that are disturbed in their ability to regulate light energy distribution between PS I and PS II. Subsequent modulated fluorescence measurements at room temperature and 77 K fluorescence emission spectra confirmed that 5 mutants (0.025% of total number screened) were defective in state transitions. [32P]orthophosphate phosphorylation experiments in vivo revealed that in one of these mutants, designated stm1, the level of LHC II polypeptide phosphorylation was drastically reduced compared with wild type. Despite WT levels of PS I and PS II, stm1 grew photoautotrophically at reduced rates, compared with WT especially under low light conditions, which is consistent with an important physiological role for state transitions. Our results highlight the feasibility of video imaging in tandem with mutagenesis as a means of identifying the genes involved in controlling state transitions in eukaryotic photosynthetic organisms.
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  • 39
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    Plant molecular biology 40 (1999), S. 711-717 
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; Arabidopsis thaliana ; binary vector ; T-DNA ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A streamlined mini binary vector was constructed that is less than 1/2 the size of the pBIN19 backbone (3.5 kb). This was accomplished by eliminating over 5 kb of non-T-DNA sequences from the pBIN19 vector. The vector still retains all the essential elements required for a binary vector. These include a RK2 replication origin, the nptIII gene conferring kanamycin resistance in bacteria, both the right and left T-DNA borders, and a multiple cloning site (MCS) in between the T-DNA borders to facilitate cloning. Due to the reduced size, more unique restriction sites are available in the MCS, thus allowing more versatile cloning. Since the traF region was not included, it is not possible to mobilize this binary vector into Agrobacterium by triparental mating. This problem can be easily resolved by direct transformation. The mini binary vector has been demonstrated to successfully transform Arabidopsis plants. Based on this mini binary vector, a series of binary vectors were constructed for plant transformation.
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  • 40
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    Plant cell, tissue and organ culture 57 (1999), S. 207-210 
    ISSN: 1573-5044
    Keywords: biolistics ; gene expression ; haploid ; transformation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the PDS-1000/He Biolistic® Particle Delivery System, the microprojectile travel distance, rupture disk pressure and DNA/gold particle concentrations were assessed in order to optimise short and longer-term β-glucuronidase reporter gene expression in microspore-derived embryos of wheat. The effects were also evaluated of using sterile filter paper to support explants and treatment with a high osmoticum medium (0.2 M mannitol/0.2 M sorbitol or 0.4 M maltose). In the optimised procedure, wheat microspore-derived embryos (MDEs), were placed on filter paper and incubated on medium containing 0.4 M maltose, for 4 h pre- and 45 h post-bombardment. Five μl pAHC25 (0.75 mg ml-1 in TE buffer) was precipitated onto 25 μl gold particles (60 mg ml-1 in sterile water), using 20 μl spermidine (0.1 M) and 50 μl CaCl2 (2.5 M). The particles were centrifuged and resuspended in 75 μl absolute ethanol prior to the preparation of 6 macrocarriers. A microprojectile travel distance of 70 mm, a rupture pressure of 1300 p.s.i., and a vacuum of 29′′ Hg were employed. Maltose at 0.4 M in the support medium was the most important factor influencing GUS activity in bombarded tissues. GUS activity, 1 day post-bombardment, reached 52 ± 17 GUS-positive foci/MDE (mean ± s.e.m, n=3), with 17 ± 4 foci/MDE at 15 days, giving a 3.0-fold increase (p〈0.05) compared to expression in MDEs bombarded on medium without a high osmoticum treatment.
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  • 41
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    Water, air & soil pollution 110 (1999), S. 57-66 
    ISSN: 1573-2932
    Keywords: DDT ; kinetic ; organic pollutant ; sediment ; sorption ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The overall objective of this study was to investigate the sorption kinetics of DDT in sediment under similar experimental conditions employed in corresponding toxicity studies for bentic organisms. A batch of aerated Schoonrewoerdse Wiel sediment, initially spiked with DDT, was sampled over a period of seven days. Concentrations of DDT, DDD and DDE were determined in both the solid and the solution phase in the sediment/water system after separation by centrifugation. It was found that the extractable amount of DDT decreased with increasing contact time. This can partly be explained in terms of transformation of DDT into DDD. Furthermore, the present applied extraction procedure seems to be less effective with increasing contact time, indicating an increase in binding strength of DDT with the sediment material. Finally, on the basis of DDT, DDE and DDD concentrations in both the solid phase and the solution phase, partition coefficients were calculated, which appeared to be independent of the contact time. This points at a very rapid equilibrating between DDT in pore water and in the extractable forms adsorbed at the solid phase.
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  • 42
    ISSN: 1573-2932
    Keywords: atmospheric fate ; atmospheric transport ; deposition ; emission ; long-range transport ; pesticides ; registration ; remote area ; risk assessment ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The Health Council of the Netherlands organised an international workshop on the fate of pesticides in the atmosphere and possible approaches for their regulatory environmental risk assessment. Approximately forty experts discussed what is currently known about the atmospheric fate of pesticides and major gaps in our understanding were identified. They favoured a tiered approach for assessing the environmental risks of atmospheric dispersion of these chemicals. In the first tier a pesticide's potential for emission during application, as well as its volatilisation potential should be assessed. Estimates of the former should be based on the application method and the formulation, estimates of the latter on a compound's solubility in water, saturated vapour pressure and octanol/water partition coefficient. Where a pesticide's potential for becoming airborne exceeds critical values, it should be subjected to a more rigorous second tier evaluation which considers its toxicity to organisms in non-target areas. This evaluation can be achieved by calculating and comparing a predicted environmental concentration (PEC) and a predicted no-effect concentration (PNEC). By applying an extra uncertainty factor the PNEC can be provisionally derived from standard toxicity data that is already required for the registration of pesticides. Depending on the distance between the source and the reception area, the PEC can be estimated for remote areas using simple dispersion, trajectory type models and for nearby areas using common dispersion models and standard scenarios of pesticide use. A pesticide's atmospheric transport potential is based on factors such as its reaction rate with OH radicals. It should be used to discriminate between those compounds for which only the risks to nearby ecosystems have to be assessed, and those for which the risks to remote ecosystems also have to be determined. The participants were of the opinion that this approach is, in principle, scientifically feasible, although the remaining uncertainties are substantial. Further field and laboratory research is necessary to gain more reliable estimates of the physico-chemical properties of pesticides, to validate and improve environmental fate models and to validate the applicability of standard toxicity data. This will increase both the accuracy of and our confidence in the outcome of the risk assessment.
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  • 43
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    Higher education 38 (1999), S. 275-290 
    ISSN: 1573-174X
    Keywords: academic staff ; curriculum change ; equity ; governance ; staff development ; student needs ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract In South Africa the restructuring of the higher education system and the transformation of higher education institutions are located within the country's broad political and socio-economic transition to democracy. This paper focuses particularly on institutional transformation, and pays attention to the implications of the process of transformation for academic staff. The following five interlinked and interdependent issues characterizing institutional transformation in South African higher education are identified: democratising the governance structures of institutions increasing access for educationally and financially disadvantaged students restructuring the curriculum focusing on developmental needs in research and community service redressing inequalities in terms of race and gender. Although the overall effect of institutional transformation is experienced rather negatively by many academic staff members, the paper concludes that academics have to be empowered by means of staff development to remain active partners in the transformation process.
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  • 44
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    Journal of engineering mathematics 36 (1999), S. 241-254 
    ISSN: 1573-2703
    Keywords: flows in porous media ; transformation ; heat transfer ; drying bins ; conformal mapping.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Abstract The design of a drying or cooling store aims to provide an even airflow distribution, when aerated, for preservation purposes. The airflow in some curved bottom bins are studied in this paper. The flow is modelled, using Darcy's law. A generalized Schwarz-Christoffel transformation is employed to reduce the problem of computing streamlines and isobars of airflow to solving a single nonlinear equation for the flow angle along the wall. Corresponding to different bin shapes, a few computed streamlines and isobars of airflow are presented, showing the effect of changing bottom geometries on the air flow. Heat transfer in such bins is also investigated. Based on an analysis of the far field of airflow, finite-height bins are considered. Analytical solutions of the heat conduction equation in terms of streamlines and isobars are obtained.
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  • 45
    ISSN: 1573-2932
    Keywords: arid-zone soils ; field capacity ; fractionation ; heavy metals ; kinetics ; redistribution ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Solid-phase transformation of added Cd, Cu, Cr, Ni, Pb and Zn, in two arid-zone soils incubated in the field capacity moisture regime for one year, were studied. The heavy metals were fractionated into six empirically defined fractions using a selective sequential dissolution (SSD) protocol optimized for arid-zone soils. Each of these fractions was named based on the major soil component targeted for dissolution during the specific SSD step, but it is not assumed that they are mineralogically and chemically totally specific. The transformations of the metals in the two soils incubated at the field capacity regime were compared with those at the moisture saturation regime (Han and Banin, 1997). An initial fast stage of transformation of the soluble metals from the exchangeable (EXC) fraction to the less labile fractions (the carbonate (CARB) fraction for Cd, Pb, Zn, Ni and Cu, and the organic matter (OM) fraction for Cr, and to some extent Cu and Ni) occurred during the fractionation and within one hour after addition. This was followed by a second stage, involving long-term transformation processes of all metals: added Cd was transferred from the EXC into the CARB fraction; added Cr was transferred from the CARB to the OM fraction and Pb was transferred very slowly to the easily reducible oxide (ERO) fraction. Added Cu, Ni and Zn were transferred from the EXC and CARB fractions into the ERO fraction and to some extent OM and RO fractions. In Part I of this series, we reported that during incubation in the saturated moisture regime, Zn and Ni were transferred mainly into the RO and OM fractions. Cadmium, Cr and Pb underwent the same transformation pathways during the slow long-term process, with slightly different rates, in both water regimes. At low levels of addition, the incubated soils moved over one year towards a distribution similar to that of the native soil. At higher levels, the soils still remained removed from the quasi-equilibrium which characterized the native soil, even at the end of one year of incubation.
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  • 46
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    Computer supported cooperative work 8 (1999), S. 63-93 
    ISSN: 1573-7551
    Keywords: activity theory ; action ; transformation ; expansive learning ; intervention ; visibilization ; health care ; medical records
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Work is commonly made visible along two dimensions: the linear and the socio-spatial. Both are limited to depicting work in terms of relatively discrete actions. Activity theory introduces the crucial distinction between collective activity systems and individual actions. Expansive visibilization of collective activity systems offers a powerful intervention methodology for dealing with major transformations of work. The linear and the socio-spatial dimensions of work actions are seen in the broader perspective of a third, developmental dimension of work activity. Four steps are identified in a cycle of expansive visibilization, combining activity-level visions and action-level concretizations. The cycle is examined in detail as it unfolded in an intervention study at a children's hospital in Finland. It is concluded that expansive visibilization, driven by contradictions and seeking to reconceptualize the object and motive of work, is not a straightforward process which can be neatly controlled from above. Coherent analytical explanation and goal-setting may come only after the creation and practical implementation of innovative solutions.
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  • 47
    ISSN: 1572-9788
    Keywords: alternative oxidase ; antisense ; male-sterility ; tapetum-specific promoter ; tobacco ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The alternative oxidase of plant mitochondria is the terminal oxidase of the cyanide-insensitive respiratory pathway and is encoded by a nuclear gene. A 1 kb genomic fragment including exon 3 of the alternative oxidase was amplified by PCR from the genome of Arabidopsis thaliana. This fragment was connected to a tapetum-specific promoter in the antisense orientation and then introduced into tobacco. The pollen viability in three transgenic plants ranged from 2% to 60%. The reduced pollen viability cosegregated with the transgene in a selfed progeny. Immunolocalization of alternative oxidase protein in the immature flower bud section indicated that expression of alternative oxidase protein in tapetum of the transgenic plant was much lower than that of the non-transformant. The histological observation and protein gel-blot analysis showed that the development of pollen grains in the transgenic plant did not progress after the degradation of the tapetum, and the amount of alternative oxidase in pollen grains of the transgenic plant became lower than that of the non-transformant. These results suggested that the alternative oxidase activity in the tapetum has a significant effect on the pollen development.
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  • 48
    ISSN: 1572-9788
    Keywords: Cyamopsis tetragonoloba ; β-lactamase inhibitor ; sulbactam ; transformation ; transgene stability ; transgenic guar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A procedure for transformation of the large-seeded endospermous legume guar (Cyamopsis tetragonoloba L.) and a study on transmission of the transgenes to offspring generations are presented. Using Agrobacterium tumefaciens with a T-DNA construct harbouring a β-glucuronidase gene (uidA) and a neomycin phosphotransferase gene (nptII), maximum transformation frequencies of cotyledonary explants were obtained using 145 mg/l kanamycin sulfate as selective agent. Carbenicillin and cefotaxime, used for the elimination of Agrobacterium after co-culture, displayed considerable toxicity to guar tissues but replacing most of these β-lactams by the non-phytotoxic β-lactamase inhibitor sulbactam as well as addition of thidiazuron and silver thiosulfate increased transformation frequencies up to 10-fold in total. The presence of the transgenes in the primary transformants was demonstrated by genomic DNA analysis of GUS-positive shoots. Chimaeric plants (5–10%) were identified by GUS analysis at the flowering stage and were discarded. Analysis of the R1 offspring from 17 independent transformants showed that in 41% of those, the uidA gene(s) was expressed and stably inherited consistent with Mendelian genetics. This was also found for the R2 and R3 generations of single copy transformants. On the other hand, a large proportion (47%) of the primary transformants gave R1 offspring in which 100% of the plants were GUS-negative. Analysis of these plants by PCR revealed that, at least, most of the transgene sequences were absent, suggesting that they had not been transmitted from the parent transformants. This occurred at similar high frequencies (40–50%) irrespective of the estimated copy number of the transgenes. Thus, major parts of the transgenes, even when present in multiple copies, displayed aberrant transmission, at a high frequency, in the process of going from the primary transformants to the first offspring generation.
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  • 49
    ISSN: 1573-9368
    Keywords: Lactuca sativa ; Agrobacterium tumefaciens ; bialaphos ; phosphinothricin acetyltransferase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Resistance to bialaphos, a broad-spectrum herbicide, was introduced into Lactuca sativa cv. Evola by Agrobacterium tumefaciens-mediated transformation. A. tumefaciens strains 0310 and 1310, both carrying the bialaphos resistance (bar) and neomycin phosphotransferase (nptII) genes, were used for transformation. Primary transformants were selected on kanamycin sulphate-supplemented shoot regeneration medium. Integration of both transgenes was confirmed by non-radioactive Southern hybridisation. The hypervirulent plasmid ToK47 in A. tumefaciens strain 1310 generated multiple insertions of T-DNA in some transgenic plants; the absence of pToK47 (strain 0310) resulted in single gene inserts in all plants tested. Resistance to glufosinate ammonium was observed in axenic seedlings grown on medium supplemented with the herbicide at 5 mg l−1 and in glasshouse-grown plants sprayed with the compound at 300 mg l−1. Stable expression of the bar gene was observed in R2 generation plants. The kanamycin resistance of R1 seedlings was observed by germinating seeds on medium supplemented with 200 mg l−1 kanamycin sulphate. The presence of NPTII protein and PAT enzyme activity were demonstrated by ELISA and PAT enzyme assay respectively. Transgenes segregated in a Mendelian fashion in some plant lines in the R1 generation; herbicide resistance also segregated in the expected ratio in the R2 generation in most transgenic lines. This study confirmed that an agronomically important transgene can be integrated and stably expressed over several generations in lettuce.
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  • 50
    ISSN: 1573-9368
    Keywords: Agrobacterium tumefaciens ; ß‐glucuronidase ; lamiaceae ; lavandin ; neomycin phosphotransferase II ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lavandin (Lavandula x Emeric ex Loiseleur) is an aromatic plant, the essential oil of which is widely used in the perfume, cosmetic, flavouring and pharmaceutical industries. The qualitative or quantitative modification of its terpenes‐containing essential oil by genetic engineering could have important scientific and commercial applications. In this study, we report the first Agrobacterium tumefaciens‐mediated gene transfer into lavandin. The transformation protocol was optimized by lengthening precultivation and cocultivation periods and by testing five different bacterial strains. We obtained transformed callus lines at a frequency of 40–70 with strains AGL1/GI, EHA105/GI and C58/GI. Transgenic shoots were regenerated from these kanamycin resistant calli and rooted on selective medium with 150 mg l-1 kanamycin. The final percentage of transgenic plants obtained varied from 3 to 9, according to the strain used, within 6 months of culture. The presence of the introduced β‐glucuronidase and neomycin phosphotransferase II genes was shown both by PCR and Southern blot analysis. Transgene expression was investigated using histoenzymatic β‐glucuronidase assays, leaf callus assays and RT‐PCR. Results showed that both β‐glucuronidase and neomycin phosphotransferase II genes were expressed at a high level in at least 41 of the transgenic plants regenerated. This efficient transformation strategy could be used to modify some genetic traits of lavandin (flower colour, pathogens resistance) and to study the biosynthesis of the major monoterpene components of its essential oil (linalool, linalyl acetate, camphor and 1,8‐cineole).
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  • 51
    ISSN: 1573-6784
    Keywords: Bacillus ; plasmids ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A simple and easy method for the introduction of plasmid DNA into different species of Bacillus was developed. The method involves the suspension in a transformation buffer of nutrient agar grown cells in their late exponential phase and the addition of unpurified plasmid DNA. Transformants were obtained at a frequency of about 103 to 105 stable transformants per μg of plasmid DNA.
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  • 52
    ISSN: 1573-5028
    Keywords: constitutive expression ; GFP ; GUS ; Musa ; ScBV ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 1369 bp DNA fragment (Sc) was isolated from a full-length clone of sugarcane bacilliform badnavirus (ScBV) and was shown to have promoter activity in transient expression assays using monocot (banana, maize, millet and sorghum) and dicot plant species (tobacco, sunflower, canola and Nicotiana benthamiana). This promoter was also tested for stable expression in transgenic banana and tobacco plants. These experiments showed that this promoter could drive high-level expression of the β-glucuronidase (GUS) reporter gene in most plant cells. The expression level was comparable to the maize ubiquitin promoter in standardised transient assays in maize. In transgenic banana plants the expression levels were variable for different transgenic lines but was generally comparable with the activities of both the maize ubiquitin promoter and the enhanced cauliflower mosaic virus (CaMV) 35S promoter. The Sc promoter appears to express in a near-constitutive manner in transgenic banana and tobacco plants. The promoter from sugarcane bacilliform virus represents a useful tool for the high-level expression of foreign genes in both monocot and dicot transgenic plants that could be used similarly to the CaMV 35S or maize polyubiquitin promoter.
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  • 53
    ISSN: 1573-8221
    Keywords: human papilloma virus ; transformation ; actin ; fibronectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Transfection of rat embryonic fibroblasts with E7 gene of type 16 human papilloma virus changed the cytoskeleton and cell-cell and cell-matrix interactions in two clones of transformed cells. Cell morphology and substrate-dependent proliferation were also changed.
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  • 54
    ISSN: 1572-9788
    Keywords: Triticum turgidum L. var. durum ; pasta wheat ; transformation ; seed protein modification ; flour quality improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Particle bombardment has been used to transform three cultivars (L35, Ofanto, Svevo) and one breeding line (Latino × Lira) of durum wheat (Triticum turgidum L. var. durum). These varieties were co-transformed with plasmids containing selectable and scorable marker genes (bar and uidA) and plasmids containing one of two high-molecular-weight (HMW) glutenin subunit genes (encoding subunits 1Ax1 or 1Dx5). Ten independent transgenic lines were recovered from 1683 bombarded scutella (transformation efficiency thus 0.6%). Five lines expressed either subunit 1Dx5 or 1Ax1 at levels similar to those of endogenous subunits encoded on chromosome 1B. To identify the effects of the transgenes on the functional properties of grain, three lines showing segregation for transgene expression were used to isolate sibling T2 plants which were null or positive for the transgene product. Analysis of these plants using a small-scale mixograph showed that expression of the additional subunits resulted in increased dough strength and stability, demonstrating that transformation can be used to modify the quality of durum wheat for bread and pasta making.
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  • 55
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    Plant molecular biology reporter 16 (1998), S. 129-131 
    ISSN: 1572-9818
    Keywords: Agrobacterium tumefaciens ; binary vector ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the construction of a binary vector for Agrobacterium tumefaciens-mediated transformation, pBIN20, which contains a superlinker region located between the left and right Ti border sequences. This vector, derived from pBI121, simplifies the cloning of plant expression cassettes and has been used in our laboratory to create lines of transgenic BY-2 tobacco cells. This new vector contains more than 20 unique restriction sites as well as the nptII selectable marker gene within the Ti-DNA borders.
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  • 56
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    GeoJournal 44 (1998), S. 215-224 
    ISSN: 1572-9893
    Keywords: cross-border region ; transformation ; regional economic development ; Poland ; Germany
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract One of the major means to foster European integration is the establishment of border spanning regions (‘Euroregions’). This is particularly important on the Eastern borders of the EU, e.g. in Eastern Germany. There, however, a double transformation to post-socialist society is taking place, both inside and outside the EU. Tensions arise between objectives on local and higher political levels, intensified by totally different economic structures and access to EU funds on both sides of the border. This is particularly true for the case of the emerging Euroregion Viadrina. Problems in preserving old industrialised localities in East Germany (e.g. steel) and attempts to resurrect the urban fair place Frankfurt/Oder, clash with transition in agriculture and consumer industries and with new concepts in tourism development and environmental protection in the Polish border zone. In region building, political, economic and ideological goals compete with each other. Local initiatives and higher political governance may both support and hamper each other. The same holds true for the interdependence of cultural integration and economic development. The paper concludes that regional economic development can only be expected if, via the building of the Euroregion, the interplay of these factors leads to compromise and harmonization between the different parties involved.
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  • 57
    ISSN: 1572-9893
    Keywords: chamber of commerce ; economy ; experts ; institutions ; local government ; Romania ; rural ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics, drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage. Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is able to grow more rapidly and attract greater foreign investment.
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  • 58
    ISSN: 1572-9893
    Keywords: agriculture ; border region ; communities ; commuting ; conservation ; Romania ; tourism ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract A most distinctive feature of the settlement pattern of the Brasov area is the extreme dispersal of mixed farming encountered in the western extreme of the county to the north and south of Zarnesti: the Bran and Poiana Marului areas. Here a system of peasant subsistence farming developed in a political borderland between the Habsburg and Ottoman Empires. Despite feudal pressures, the peasantry took all available opportunities to extend their independence including elaborate transhumance systems. And after seeing transfrontier commerce as a source of plunder, in the tradition of Balkan highway robbery within relatively unregulated spaces, the peasantry has profited through employment in factories, particularly during the communist period. However, the current recession in manufacturing is throwing the rural population back on limited land resources. Although farming assumes an important subsistence role which contributes to stability, the long-term survival of these communities will depend on new sources of income. Rural tourism has considerable potential and a promising start has been made in Bran. There are, however, constraints on the further development of the business and great attention will have to be given to the conservation of the environment in both the Bucegi Mountains and the Piatra Craiului where national park status is proposed.
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  • 59
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    GeoJournal 46 (1998), S. 263-269 
    ISSN: 1572-9893
    Keywords: Croatia ; decentralisation ; diversification ; industry ; innovation ; rural ; transformation ; urbanisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Rural diversification in Croatia is well advanced because many rural families have been able to find work in secondary and tertiary activities without the need to migrate to the towns. Many rural settlements have now attained an urban character although there are regional variations, including a contrast between the continental zone with a relatively high level of commitment to agriculture and the coastal areas, with pronounced ‘deagrarisation’ where the ports and tourist resorts are well developed and the natural resource conditions for agriculture are poor. These variations are examined at the municipality level with reference to two key indicators: the share of nonagricultural population and the share of workers in the total active population. Four categories of socio-economic transformation are recognised: more urbanised, urbanised, less urbanised and rural. The main regional differences between the continental and coastal areas are confirmed with the latter showing a relatively high level of socio-economic transformation through the prominence of more highly urbanised municipalities.
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  • 60
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    Breast cancer research and treatment 47 (1998), S. 197-199 
    ISSN: 1573-7217
    Keywords: breast cancer ; insulin-like growth factor system ; IGF-I receptor ; IGF-II receptor ; binding proteins ; prognosis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In 1992, a special issue of Breast Cancer Research and Treatment was devoted to the insulin-like growth factors and breast cancer. In that issue, identification of the key components of the IGF system was reviewed and their potential role in breast cancer growth was described. In this issue, we revisit the IGF system with particular attention to data that further supports their role in the growth regulation of breast cancer. Several new facets of the IGF system are described, and several laboratories have more clearly defined how each individual component of the IGF system may influence breast cancer biology.
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  • 61
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    Antonie van Leeuwenhoek 73 (1998), S. 147-153 
    ISSN: 1572-9699
    Keywords: transformation ; plasmid integration ; Phaffia rhodozyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stable red astaxanthin-producing transformants were obtained after genetic transformation of two Phaffia rhodozyma mutants. A yellow mutant, accumulating β-carotene, and an albino mutant, accumulating phytoene, from P. rhodozyma were transformed using a genomic library of wild-type strain UCD 67-385 in the pBluescript vector. Hybridization assays, using the pBluescript DNA as a radioactive probe, indicate integration of vector sequences into the genome of the transformants. Transformants DNA was digested with restriction endonucleases, ligated with T4 DNA ligase and then used to transform E. coli. Ampicillin resistant plasmids, containing 0.1, 0.2, and 2.5 kb DNA inserts of P. rhodozyma, were rescued from the yeast red transformants. The molecular analysis indicate that transformation has occurred by an integration event of donor DNA into the genome of the host strains.
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  • 62
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    Euphytica 100 (1998), S. 219-223 
    ISSN: 1573-5060
    Keywords: cereals ; wheat ; transformation ; genetic modification ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A method for efficient genetic transformation of wheat has been developed using immature embryos as targets for microprojectile-mediated gene transfer and a helium driven particle delivery system. Screening and selection of transgenic cells, somatic embryos and regenerated plants are performed with the gus-gene and the phosphinothricin acetyl transferase (bar) gene coding for Basta-resistance as the selectable marker. On average, one fertile transgenic plant can be obtained from about 100 microprojectile treated, immature embryos. The number of integrated copies of the transferred gene ranges from 1 up to about 10. Stable integrated genes are inherited in most of the transgenic lines in a normal mendelian fashion segregating 3:1 in the F2. Homozygous, as well as heterozygous, lines have been followed and analysed genetically at the molecular level and up to F5. Apart from normal stable gene expression, examples have also been found which showed a loss of gene activity or unexpected segregation pattern. For applied aspects, different genes are transferred aiming for improved disease resistance, modification of quality, or other characteristics. First results from these transgenic lines are reported, and problems still existing with the production of stable transgenic wheat lines are discussed.
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  • 63
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    Plant cell, tissue and organ culture 55 (1998), S. 175-181 
    ISSN: 1573-5044
    Keywords: Conifer ; transformation ; virulence genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As a preliminary step in efforts to develop a successful protocol for Agrobacterium-mediated transformation of cotyledonary explants of Pinus pinea L. embryos, we tested the ability of embrionary exudates of this species to induce the expression of the virulence genes virA, virB, virC, virD, virE and virG in Agrobacterium tumefaciens containing vir: lacZ fusion constructs. The results obtained in the vir induction assay indicated the absence of bactericidal or bacteriostatic plant compounds affecting A. tumefaciens growth, and showed that cotyledonary and embrionary exudates of P. pinea are able to induce all virulence genes studied, except virG. The data suggest that A. tumefaciens can be used for gene transfer into this important forest and fruit species.
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  • 64
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    Environmental and ecological statistics 5 (1998), S. 197-222 
    ISSN: 1573-3009
    Keywords: kriging ; non-separable space-time correlation ; spatial scale ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We present an approach to estimate hourly grid-cell surface ozone concentrations based on observations from point monitoring sites in space, for comparison with grid-based results from the SARMAP photochemical air-quality model for a region of northern California. Statistical estimation is carried out on a transformed (square root) scale, followed by back-transforming to the original scale of ozone in parts per billion, adjusting for bias and variance. We estimate a spatially-varying diurnal mean structure and a non-separable space-time correlation structure on the transformed scale. Temporal pre-whitening is followed by modelling of a spatially non-stationary, diurnally-varying spatial correlation structure using a spatial deformation approach. Comparisons of SARMAP model results with the estimated grid-cell ozone levels are presented.
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  • 65
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2209-2214 
    ISSN: 0887-624X
    Keywords: cationic polymerization ; anionic polymerization ; transformation ; samarium ; block copolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transformation of the cationic growing center of living poly(tetrahydrofuran) [poly(THF)] into an anionic one was achieved in high efficiency (62%) by the end-capping of living poly(THF) with potassium iodide followed by the reduction with bis(pentamethylcyclopentadienyl)samarium (Cp*2Sm), whereas the direct reduction with Cp*2Sm without the end-capping resulted in the formation of poly(THF) with pentamethylcyclopentadienyl group at the terminal. The increase in the molecular weight of poly(THF) after the reduction was observed, which indicates the presence of the dimerization of poly(THF) during the reduction. The polymerization of a variety of electrophilic monomers including δ-valerolactone, 2-oxo-1,3-dioxane, and alkyl methacrylates with the macroanion provided good yields of the corresponding block copolymers consisting of both cationically and anionically polymerizable monomers. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2209-2214, 1998
    Additional Material: 4 Ill.
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  • 66
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    Social indicators research 43 (1998), S. 197-209 
    ISSN: 1573-0921
    Keywords: transformation ; anomie ; social integration ; state ; quality of life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology
    Notes: Abstract The weakening of social integration and anomie are unavoidable in the transformation of societies. The effect is a decrease of quality of life accompanied by disenchantments, aggressiveness and escapism. In some countries in Eastern Europe like Bulgaria the anomie effects of transformation became particularly strong. The major reason is the political instability. The dissolution of the previous state-centered over-integration of society developed into a dissolution of major mechanisms of political integration. The prospects for improvement of quality of life are focused on the balance of economic, political and cultural re-integration of Bulgarian society.
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  • 67
    ISSN: 1572-9788
    Keywords: antisense ; chalcone synthase ; flower colour ; lisianthus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three cultivars of lisianthus (Eustoma grandiflorum (Grise.)) were transformed with a homologous antisense CHS cDNA via Agrobacterium-mediated transformation. Over 50% of the transgenics derived from the purple flowering lines exhibited an altered flower colour pattern ranging from small streaks of white on the wild-type purple background through to completely white flowers. A significant portion of the transgenic lines showed unstable phenotypes. Northern and biochemical analysis showed that the altered flower patterns were associated with a loss of CHS gene transcript and a corresponding loss of CHS enzyme activity. In the white flowering line the level of total flavonoids was reduced to ca. 2.0% of the wild-type level. Some of the transgenic plants also exhibited alterations in flower form such as the formation of frilled petal tips and reduced flower opening. Several of the new patterned lines are being evaluated for stability and possible commercial release.
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  • 68
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    Molecular breeding 4 (1998), S. 531-541 
    ISSN: 1572-9788
    Keywords: Agrobacterium ; Brassica oleracea ; cauliflower ; regeneration ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have developed an efficient and simpler method for genetic transformation and regeneration of cauliflower, Brassica oleracea var. botrytis plants. Explants from 4-day old seedlings were inoculated and cocultivated with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector with the neomycin phosphotransferase-II gene under the regulatory control of nopaline synthase promoter and terminator sequences, permitting transformed shoots to be selected on kanamycin containing medium. After three months rooted transformed plantlets were successfully transferred and grown under glasshouse conditions. Higher numbers of transformed plants were obtained from cotyledon than hypocotyl explants, presumably indicating cotyledons of cauliflower are more amenable to genetic transformation. Integration and expression of the introduced transgene were analysed by DNA gel blot and PCR analysis and NPT-II expression assay. Factors influencing transformation efficiency include explant age, concentration of bacterium used for infection, duration of infection and cocultivation with Agrobacterium. Transgenic plants of three commercial genotypes of cauliflower were produced using this method. We also show that introduction of antisense Bcp1 (pollen-specific gene) linked to a pollen-specific promoter (Lat52) resulted in the expected sterility of 50% pollen carrying this transgenic construct.
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  • 69
    ISSN: 1573-9368
    Keywords: Saccharum ; Agrobacterium ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This is the first successful report of the recovery of morphologically normal transgenic sugarcane plants from co-cultivation of calluses with Agrobacterium tumefaciens. Transformation frequencies (total of transgenic plants/number of cell clusters) were between 9.4 × 10−3 and 1.15 × 10−2. In our experiments, both LBA4404 (pTOK233) and EHA101 (pMTCA3IG), carrying a super-binary vector or supervirulent strain, respectively, were successful for sugarcane transformation. We found that three main factors: (1) the use of young regenerable calluses as target explants; (2) induction and/or improvement of the A. tumefaciens virulence system with sugarcane cell cultures and (3) pre-induction of organogenesis or somatic-embryogenesis-like sexual embryos, seem to be crucial in order to increase the cells competence for T-DNA transfer process. Patterns generated by Southern hybridization confirmed that T-DNAs were randomly integrated into sugarcane genome without th e persistence of A. tumefaciens in the transgenic plants
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  • 70
    ISSN: 1573-9368
    Keywords: Oryza sativa ; particle bombardment ; transformation ; transgenic rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We developed a practical and efficient gene transfer system for indica rice utilizing mature-seed derived explants and a simple bombardment device which uses compressed helium for accelerating DNA-coated metal particles. Unlike instruments which have been described in the literature previously, this new bombardment device, which is an improvement of the particle inflow concept, does not require vacuum. This attribute simplifies the transformation procedure significantly and it makes rice transformation technology accessible to laboratories which may not have the resources to invest in more expensive particle bombardment instruments. We determined experimentally that we could recover transgenic rice plants utilizing three different particle bombardment instruments at comparable frequencies.
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  • 71
    ISSN: 1573-9368
    Keywords: sweet orange ; Citrus ; woody ; transformation ; Agrobacterium ; mature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regeneration and transformation systems from mature plant material of woody fruit species have to be achieved as a necessary requirement for the introduction of useful genes into specific cultivars and the rapid evaluation of resulting horticultural traits. We report here, for the first time, a procedure for genetic transformation and regeneration of mature tissues of woody plants that overcomes the long juvenile periods and high heterozygosity that are characteristic of most of these species. An improved regeneration frequency from mature explants was obtained by invigoration of the plant material through grafting of mature buds on juvenile seedlings. Co-cultivation of the explants in feederplates after inoculation with Agrobacterium tumefaciens resulted in enhanced transformation frequencies. Furthermore, in vitro shoot-tip grafting of the regenerated mature shoots on seedling rootstocks provided a rapid and efficient system for plant production. Citrus is the most extensivel y grown fruit crop worldwide and sweet orange (Citrus sinensis L. Osbeck) accounts for approximately 70% of the Citrus total production. Mature transgenic sweet orange plants have been obtained, which flowered and bore fruit in 14 months
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  • 72
    ISSN: 1573-9368
    Keywords: chimaera ; iterative culture ; regeneration ; strawberry ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic plants of strawberry cultivar Totem were developed by Agrobacterium-mediated transformation using a plasmid vector containing gus and nptII genes. Parallel experiments were carried out with and without repeated subculturing (iterative cultures) for generation of transgenic shoots on selection medium. The selection levels in the non-iterative pathway were kept constant, while in the iterative protocol, stepwise increase of selection pressure was applied at different stages of tissue growth. Rooted transgenic plants obtained via both protocols were outplanted in soil. Random leaf samples of greenhouse-grown transgenics were analysed for the presence of gus gene sequences by Southern hybridization as well as gus expression on leaf and petiole tissues by X-Gluc histological assay. Random leaf samples analysed from individual transgenic events developed under iterative culture were positive for the gus insert as verified by Southern analysis confirming the presence of transgenes and lack of chimaeras. Leaf samples of the transgenic events from the non-iterative protocol were either positive or negative on Southern analysis indicating the chimaeric nature of the transgenic plants. The absence of gus sequences in the transgenic plants grown under the non-iterative protocol reinforced the necessity of iterative cultures along with stepwise increase in selection levels for generating non-chimaeric transgenics in strawberry. The gus expression was highly variable, irrespective of the iterative or non-iterative protocol used for transformation. We conclude that strawberry is highly prone to develop chimaeric transgenics if derived from primary regenerants and that the iterative culture technique effectively converts chimaeras to pure line transgenic plants
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  • 73
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    Biotechnology techniques 12 (1998), S. 829-832 
    ISSN: 1573-6784
    Keywords: Pseudomonas oleovorans ; electroporation ; transformation ; poly(β-hydroxyalkanoate) ; alkane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract An electroporation procedure for the transformation of Pseudomonas oleovorans was developed using a model plasmid, pCN51. The optimal electrotransformation was achieved with cells harvested at 45 to 60 min of growth and concentrated to a cell density of 5 OD600nm, plasmid concentration of 6 μg per 100 μl of cell suspension, and a 0.1-cm gap-width cuvette. Electroporation was performed at the settings of 250 ω, 25μF and 2.5 kV. Transformation yields in the order of 103 colony-forming-unit per electroporation sample were obtained. This is a first report of the electroporation of the commercially valuable bacterium Ps. oleovorans. © Rapid Science Ltd. 1998
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  • 74
    ISSN: 1573-5028
    Keywords: Agrobacterium ; apple ; GFP ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate early events of Agrobacterium-mediated transformation of apple cultivars, a synthetic green fluorescent protein gene (SGFP) was used as a highly sensitive, vital reporter gene. Leaf explants from four apple cultivars (‘Delicious’, ‘Golden Delicious’, ‘Royal Gala’ and ‘Greensleeves’) were infected with Agrobacterium EHA101 harboring plasmid pDM96.0501. Fluorescence microscopy indicated that SGFP expression was first detected 48 h after infection and quantitative analysis revealed a high T-DNA transfer rate. Plant cells with stably incorporated T-DNA exhibited cell division and developed transgenic calli, followed by formation of transgenic shoots at low frequencies. The detection of SGFP expression with an epifluorescence stereomicroscope confirmed the effectiveness of SGFP as a reporter gene for detection of very early transformation events and for screening of putative transformants. The efficiency of the transformation and regeneration process decreased ca. 10000-fold from Agrobacterium infection to transgenic shoot regeneration, suggesting that factors other than Agrobacterium interaction and T-DNA transfer are rate-limiting steps in Agrobacterium-mediated transformation of apple.
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  • 75
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    Plant molecular biology 38 (1998), S. 597-607 
    ISSN: 1573-5028
    Keywords: transgene silencing ; epigenetics ; transgene expression ; transgenic plants ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An irregular pattern of transgene silencing was revealed in expression and inheritance studies conducted over multiple generations following transgene introduction by microprojectile bombardment of allohexaploid cultivated oat (Avena sativa L.). Expression of two transgenes, bar and uidA, delivered on the same plasmid was investigated in 23 transgenic oat lines. Twenty-one transgenic lines, each derived from an independently selected transformed tissue culture, showed expression of both bar and uidA while two lines expressed only bar. The relationship of the transgenic phenotypes to the presence of the transgenes in the study was determined using (1) phenotypic scoring combined with Southern blot analyses of progeny, (2) coexpression of the two transgenic phenotypes since the two transgenes always cosegregated, and (3) reactivation of a transgenic phenotype in self-pollinated progenies of transgenic plants that did not exhibit a transgenic phenotype. Transgene silencing was observed in 19 of the 23 transgenic lines and resulted in distorted segregation of transgenic phenotypes in 10 lines. Silencing and inheritance distortions were irregular and unpredictable. They were often reversible in a subsequent generation of self-pollinated progeny and abnormally segregating progenies were as likely to trace back to parents that exhibited normal segregation in a previous generation as to parents showing segregation distortions. Possible causes of the irregular patterns of transgene silencing are discussed.
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  • 76
    ISSN: 1573-5028
    Keywords: plants ; positive selection ; selectable marker ; Thermoanaerobacterium thermosulfurogenes ; transformation ; xylose isomerase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The xylose isomerase gene (xylA) from Thermoanaerobacterium thermosulfurogenes (formerly Clostridium thermosulfurogenes) has been expressed in three plant species (potato, tobacco, and tomato) and transgenic plants have been selected on xylose-containing medium. The xylose isomerase gene was transferred to the target plant by Agrobacterium-mediated transformation. The xylose isomerase gene was expressed using the enhanced cauliflower mosaic virus (CaMV) 35S promoter and the Ω′ translation enhancer sequence from tobacco mosaic virus. Unoptimized selection studies showed that, in potato and tomato, the xylose isomerase selection was more efficient than the established kanamycin resistance selection, whereas in tobacco the opposite was observed. Efficiency may be increased by optimization. The xylose isomerase system enables the transgenic cells to utilize xylose as a carbohydrate source. It is an example of a positive selection system because transgenic cells proliferate while non-transgenic cells are starved but still survive. This contrasts to antibiotic or herbicide resistance where transgenic cells survive on a selective medium but non-transgenic cells are killed. The results give access to a new selection method which is devoid of the disadvantages of antibiotic or herbicide selection.
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  • 77
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Avena sativa ; badnavirus promoter ; constitutive and vascular expression ; GUS staining ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regions of the sugarcane bacilliform badnavirus genome were tested for promoter activity. The genomic region spanning nucleotides 5999–7420 was shown to possess promoter activity as exemplified by its ability to drive the expression of the coding region of the uidA gene of Escherichia coli, in both Avena sativa and Arabidopsis thaliana. In A. sativa, the promoter was active in all organs examined and, with the exception of the anthers where the expression was localized, this activity was constitutive. In A. thaliana, the promoter activity was constitutive in the rosette leaf, stem, stamen, and root and limited primarily to vascular tissue in the sepal and the silique. The transgene was inherited and active in progeny plants of both A. sativa and A. thaliana.
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  • 78
    ISSN: 1572-9788
    Keywords: amylose ; antisense RNA ; endogenous allele ; Solanum tuberosum ; T-DNA insertion ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The T-DNA composition was analysed of twelve potato genotypes obtained after transforming a tetraploid cultivar with an antisense granule-bound starch synthase (GBSSI) gene. In five transformants (labelled TB50 nos.) the antisense GBSSI gene was driven by the CaMV 35S promoter, while in the remaining seven (labelled TBK50 nos.) the GBSSI promoter was used. In these twelve transformants the antisense effect on amylose production in potato tuber starch ranged from complete suppression to no discernible inhibition, and the number of T-DNA insertions ranged from one to at least fifteen. The antisense effect of individual T-DNA loci in progeny of these transformants was studied. Progeny containing a single T-DNA showed no inhibition of GBSSI activity. Only multiple, linked T-DNA insertions resulted in substantial antisense inhibition. T-DNA fragments present in duplex in selfed progeny resulted in a larger antisense effect than that in the parent (which contained the T-DNA insertions in simplex). Furthermore, the antisense effects of some T-DNA-containing linkage groups were influenced by the composition of endogenous GBSSI alleles. For practical breeding this implies that (1) the efficiency of obtaining primary potato transformants showing complete inhibition of GBSSI gene expression by antisense RNA is genotype-dependent, and (2) many transformants have to be produced per genotype to be able to select plants with maximum suppression of GBSSI and a minimum number of T-DNA loci.
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  • 79
    ISSN: 1572-9788
    Keywords: Indica rice ; cell suspension ; transformation ; Xa21 ; bacterial leaf blight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The agronomically important Indica (group 1) rice varieties IR64, IR72, hybrid restorer line Minghui 63, and BG90-2 were co-transformed by microbombardment of embryogenic suspensions with plasmids that contain the Xa21 gene which confers resistance to Xanthomonas oryzae pv. oryzae and the hph gene for resistance to hygromycin B. Six of the 55 transgenic R0 plant lines containing the Xa21 gene displayed high levels of resistance to the pathogen, and no partial resistance was observed. The trait was stably inherited in subsequent generations, and transgenic plants are currently in field tests. The ability to transfer agronomically important genes into elite Indica rice varieties demonstrates the applicability of genetic engineering for the agronomic improvement of rice.
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  • 80
    ISSN: 1572-9788
    Keywords: Bt genes ; transformation ; protection against insects ; cry1Ia5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A cry1Ia5 insecticidal toxin coding gene has been cloned from an Indian isolate of Bacillus thuringiensis. Sequence analyses of the cry1Ia5 gene revealed the absence of potential polyadenylation signal sequences thus making it a suitable candidate for expression in plants without extensive modification. This possibility was examined by subcloning the cry1Ia5 gene into a plant expression vector and then transferring it to Nicotiana tabacum through Agrobacterium-mediated transformation. Our results demonstrate that N. tabacum with a stably integrated native cry1Ia5 gene afforded complete protection against predation by Heliothis armigera. Forty three percent of the transgenic plants displayed a high level of protection against insect predation. The protection obtained in transgenic plants with the cry1Ia5 gene was comparable to that obtained with the synthetically modified cry1A(b) or cry1A(c) genes. The results demonstrate that novel insecticidal genes already exist in nature that do not require extensive modifications for efficient expression in plants.
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  • 81
    ISSN: 1572-9788
    Keywords: glycerol-3-phosphate acyltransferase ; phosphatidylglycerol ; chilling tolerance ; transformation ; fatty acid composition ; Oryza sativa L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The chilling sensitivity of several plant species is closely correlated with the levels of unsaturation of fatty acids in the phosphatidylglycerol (PG) of chloroplast membranes. Plants with a high proportion of unsaturated fatty acids, such as Arabidopsis thaliana, are resistant to chilling, whereas species like squash with only a low proportion are rather sensitive to chilling. The glycerol-3-phosphate O-acyltransferase (GPAT) enzyme of chloroplasts plays an important role in determining the levels of PG fatty acid desaturation. A cDNA for oleate-selective GPAT of Arabidopsis under the control of a maize Ubiquitin promoter was introduced into rice (Oryza sativa L.) using the Agrobacterium-mediated gene transfer method. The levels of unsaturated fatty acids in the phosphatidylglycerol of transformed rice leaves were found to be 28% higher than that of untransformed controls. The net photosynthetic rate of leaves of transformed rice plants was 20% higher than that of the wild type at 17°C. Thus, introduction of cDNA for the Arabidopsis GPAT causes greater unsaturation of fatty acids and confers chilling tolerance of photosynthesis on rice.
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  • 82
    ISSN: 1572-9788
    Keywords: Beta vulgaris ; mannose selection ; phosphomannose isomerase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Various factors affecting mannose selection for the production of transgenic plants were studied using Agrobacterium tumefaciens-mediated transformation of sugar beet (Beta vulgaris L.) cotyledonary explants. The selection system is based on the Escherichia coli phosphomannose isomerase (PMI) gene as selectable gene and mannose as selective agent. Transformation frequencies were about 10-fold higher than for kanamycin selection but were only obtained at low selection pressures (1.0–1.5 g/l mannose) where 20–30% of the explants produced shoots. The non-transgenic shoots were eliminated during the selection procedure by a stepwise increase in the mannose concentration up to 10 g/l. Analysis of the transformed shoots showed that the PMI activity varied from 2.4 mU/mg to 350 mU/mg but the expression level was independent of the selection pressure. Complete resistance to mannose of transformed shoots was observed already at low PMI activities (7.5 mU/mg). Genomic DNA blot analysis confirmed the presence of the PMI gene in all transformants analysed. The possible mode of action of mannose selection compared to other selection methods is discussed.
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  • 83
    ISSN: 0730-2312
    Keywords: cathepsin-B ; tissue transglutaminase ; mesangial cell apoptosis ; mRNA expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Mesangial matrix is a dynamic structure which modulates mesangial cell function. Since accumulation of matrix precedes the development of focal glomerulosclerosis, we studied the effect of different matrices on mesangial cell (MC) apoptosis. Suspended mesangial cells became apoptotic in a time dependent manner. Collagen type III did not modulate MC apoptosis when compared to cells grown on plastic. MCs grown on Matrigel, collagen type I and IV showed an increased number of apoptotic cells when compared to MCs grown on plastic. DNA end-labeling further confirmed these observations. MCs grown on Matrigel showed enhanced (P 〈 0.05) mRNA expression for tissue transglutaminase (TTG) and cathepsin-B. Mesangial cells grown on Matrigel also showed enhanced expression of superoxide dismutase (SOD). We conclude that mesangial cells require attachment to the matrix for their survival and alteration of the quality of matrix modulates mesangial cell apoptosis. J. Cell. Biochem. 68:22-30, 1998. © 1998 Wiley-Liss, Inc.
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  • 84
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    Journal of Cellular Biochemistry 68 (1998), S. 31-49 
    ISSN: 0730-2312
    Keywords: Bax ; Bcl-2 ; Bcl-X ; bone ; programmed cell death ; p53 ; c-fos ; Msx-2 ; differentiation ; IRF-1 ; IRF-2 ; collagenase gene expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We present evidence of cell death by apoptosis during the development of bone-like tissue formation in vitro. Fetal rat calvaria-derived osteoblasts differentiate in vitro, progressing through three stages of maturation: a proliferation period, a matrix maturation period when growth is downregulated and expression of the bone cell phenotype is induced, and a third mineralization stage marked by the expression of bone-specific genes. Here we show for the first time that cells differentiating to the mature bone cell phenotype undergo programmed cell death and express genes regulating apoptosis. Culture conditions that modify expression of the osteoblast phenotype simultaneously modify the incidence of apoptosis. Cell death by apoptosis is directly demonstrated by visualization of degraded DNA into oligonucleosomal fragments after gel electrophoresis. Bcl-XL, an inhibitor of apoptosis, and Bax, which can accelerate apoptosis, are expressed at maximal levels 24 h after initial isolation of the cells and again after day 25 in heavily mineralized bone tissue nodules. Bcl-2 is expressed in a reciprocal manner to its related gene product Bcl-XL with the highest levels observed during the early post-proliferative stages of osteoblast maturation. Expression of p53, c-fos, and the interferon regulatory factors IRF-1 and IRF-2, but not cdc2 or cdk, were also induced in mineralized bone nodules. The upregulation of Msx-2 in association with apoptosis is consistent with its in vivo expression during embryogenesis in areas that will undergo programmed cell death. We propose that cell death by apoptosis is a fundamental component of osteoblast differentiation that contributes to maintaining tissue organization. J. Cell. Biochem. 68:31-49, 1998. © 1998 Wiley-Liss, Inc.
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  • 85
    ISSN: 0730-2312
    Keywords: somatostatin ; receptor isotypes ; adenylyl cyclase ; Interleukin-2 (IL-2) ; proliferation ; Jurkat cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The neuropeptide somatostatin (SRIF) modulates normal and leukemia T cell proliferation. However, neither molecular isotypes of receptors nor mechanisms involved in these somatostatin actions have been elucidated as yet. Here we show by using RT-PCR approach that mitogen-activated leukemia T cells (Jurkat) express mRNA for a single somatostatin receptor, sst3. This mRNA is apparently translated into protein since specific somatostatin binding sites (KI1 = 78 ± 3 pM) were detected in semipurified plasma membrane preparations by using 125I-Tyr1-SRIF14 as a radioligand. Moreover, somatostatin inhibits adenylyl cyclase activity with similar efficiency (IC50 = 23 ± 4 pM) thus strongly suggesting a functional coupling of sst3 receptor to this transduction pathway. The involvement of sst3 receptor in immuno-modulatory actions of somatostatin was assessed by analysis of neuropeptide effects on IL-2 secretion and on proliferation of mitogen-activated Jurkat cells. Our data show that in the concentrations comprised between 10 pM and 10 nM, somatostatin potentiates IL-2 secretion. This effect is correlated with somatostatin-dependent increase of Jurkat cell proliferation since the EC50 concentrations for both actions were almost identical (EC50 = 22 ± 9 pM and EC50 = 12 ± 1 pM for IL-2 secretion and proliferation, respectively). Altogether, these data strongly suggest that in mitogen-activated Jurkat cells, somatostatin increases cell proliferation through the increase of IL-2 secretion via a functional sst3 receptor negatively coupled to the adenylyl cyclase pathway. J. Cell. Biochem. 68:62-73, 1998. © 1998 Wiley-Liss, Inc.
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  • 86
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    Journal of Cellular Biochemistry 68 (1998), S. 74-82 
    ISSN: 0730-2312
    Keywords: cell culture ; nuclei ; nuclear degradation ; endonucleases ; polycytosine degradation ; differentiation ; cornification ; stratum corneum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Desquamin is a glycoprotein that we have isolated from the upper granular layer and the stratum corneum of human epidermis; it is not ordinarily expressed in submerged cultures, whose terminal differentiation stops short of formation of these layers. The exogenous addition of desquamin to human cultured keratinocytes extended their maturation, and hematoxylin staining indicated a loss of cell nuclei. For confirmation, cultured cells were lysed in situ, and the nuclei were incubated with desquamin for several days, then stained with hematoxylin. Damage to the nuclei was evident: the nuclear inclusions remained intact, while the surrounding basophilic nuclear matrix was degraded. Desquamin was then tested directly for nuclease activity. Ribonuclease activity was determined by incubating desquamin with human epidermal total RNA and monitoring the dose-dependent disappearance of the 28S and 18S ribosomal RNA bands in an agarose/formaldehyde gel. On RNA-containing zymogels, we confirmed the RNase activity to be specific to desquamin. Using synthetic RNA homopolymers, we found the active RNase domains to be limited to cytosine residues. On the contrary, DNA was not degraded by an analogous procedure, even after strand-separation by denaturation. J. Cell. Biochem. 68:74-82, 1998. © 1998 Wiley-Liss, Inc.
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  • 87
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 100-109 
    ISSN: 0730-2312
    Keywords: carcinogens ; mitochondrial DNA ; nuclear DNA ; LINE ; mobile elements ; cancer ; Huntington's disease ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The nuclear DNA of normal and tumor mouse and rat tissue was examined for mitochondrial-DNA-like inserts by means of the Southern blot technique. The two probes were 32P-labeled cloned mitochondrial DNA. KpnI, which doesn't cut either mitochondrial DNA, was one of the restriction enzymes, while the enzymes that fragment mitochondrial DNA were for mouse and rat PstI and BamHI, respectively. When KpnI alone was used in the procedure a nuclear LINE family whose elements had mitochondrial-DNA-like insertions was selected. Such elements were much more abundant in tumor than in normal tissue. The results with PstI alone and BamHI alone and each combined with KpnI indicated that there were mobile LINE elements with mitochondrial-DNA-like inserts in the nuclear genome of tumor. The mouse tissues were normal liver and a transplantable lymphoid leukemic ascites cell line L1210 that had been carried for 40 years. The rat tissues were normal liver and a hepatoma freshly induced by diethylnitrosoamine in order to minimize the role of 40 years of transplantation. Our unitary hypothesis for carcinogenesis of 1971, which suggested these experiments, has been augmented to include mobile nuclear elements with inserts of mitochondrial-DNA-like sequences. Such elements have been related to diseases of genetic predisposition such as breast cancer and Huntington's disease. J. Cell. Biochem. 68:100-109, 1998. © 1998 Wiley-Liss, Inc.
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  • 88
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 121-127 
    ISSN: 0730-2312
    Keywords: heme oxygenase ; stress protein ; overexpression ; oxidative injury ; endothelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Heme oxygenase (HO-1) is a stress protein that has been suggested to participate in defense mechanisms against agents that induce oxidative injury such as hemoglobin/heme, hypoxia-ischemia and cytokines. Overexpression of HO-1 in endothelial cells (EC) might, therefore, protect against oxidative stress produced under these pathological conditions, by generation of CO, a vasodilator, and bilirubin, which has antioxidant properties that enhance blood vessel formation to counteract hypoxia-induced injury. A plasmid containing the cytomegalovirus promoter (pCMV) neomycin human HO-1 gene complexed to cationic liposomes, lipofectin, was used to transfect rabbit coronary microvessel EC. Cells transfected with human HO-1 gene demonstrated a twofold increase in HO activity and maintained a similar phenotype as in the nontransfected cells. Cell number in transfected cells with human HO-1 gene increased by about 45%, as compared to nontransfected or those transfected with control pCMV. Transfected and nontransfected EC revealed a similar response to basic fibroblast growth factor (bFGF) in capillary formation. However, transfected cells with the human HO-1 gene exhibited a twofold increase in blood vessel formation. The angiogenic response of EC to overexpression of HO-1 gene provides direct evidence that the inductive form of HO-1 following injury represents an important tissue adaptive mechanism for moderating the severity of cell damage produced in inflammatory reaction sites of hemorrhage, thrombosis and hypoxic-ischemia. Thus, HO-1 may participate in the regulation of EC activation, proliferation and angiogenesis. J. Cell. Biochem. 68:121-127, 1998. © 1998 Wiley-Liss, Inc.
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  • 89
    ISSN: 0730-2312
    Keywords: tyrosine phosphorylation ; insulin signaling ; tyrosine kinase ; confocal microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The recently identified 53-kDa substrate of the insulin receptor family was further characterized in several retroviral-generated stable cell lines overexpressing the wild type and various mutant forms of the protein. To facilitate the study of its subcellular localization in NIH3T3 cells overexpressing insulin receptor, a myc epitope-tag was added to the carboxy terminus of the 53-kDa protein. Like the endogenous protein in Chinese hamster ovary cells, the expressed myc-tagged 53-kDa protein was found partially in the particulate fraction and was tyrosine phosphorylated in insulin-stimulated cells. Immunofluorescence studies showed for the first time that a fraction of the 53-kDa protein was localized to the plasma membrane. Confocal microscopy of cells double-labeled with antibodies to the insulin receptor and the myc epitope showed the two proteins co-localize at the plasma membrane at the level of light microscopy. Further analyses of the protein sequence of the 53-kDa substrate revealed the presence of a putative SH3 domain and two proline-rich regions, putative binding sites for SH3 and WW domains. Disruption of these three motifs by the introduction of previously characterized point mutations did not affect the membrane localization of the 53-kDa protein, its ability to serve as substrate of the insulin receptor, or its colocalization with the insulin receptor, suggesting these domains are not important in the subcellular targeting of the protein and instead may function in the interaction with subsequent signaling proteins. J. Cell. Biochem. 68:139-150, 1998. © 1998 Wiley-Liss, Inc.
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  • 90
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    Journal of Cellular Biochemistry 68 (1998), S. 151-163 
    ISSN: 0730-2312
    Keywords: Type I procollagen ; proto-oncogenes ; steroid ; calcitriol ; osteoblast ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Changes in the synthesis of type I collagen, the major extracellular matrix component of skin and bone, are associated with normal growth, tissue repair processes, and several pathological conditions. Expression of the COL 1A1 gene is regulated by transcriptional and post-transcriptional mechanisms. However, the hormonal regulation of type I collagen synthesis in human bone has not been well characterized. We have studied the influence of calcitriol, dexamethasone, retinoic acid, and estradiol on the COL 1A1 gene expression by determining the secretion of the C-terminal propeptide (PICP) and the levels of α1(I) procollagen mRNA in cultured human MG-63 and SaOs-2 osteoblast-like osteosarcoma cells. Similar experiments were also performed with respect to expression of the nuclear proto-oncogenes, c-fos and c-jun, in MG-63 cells.In MG-63 cells, calcitriol stimulated the synthesis and secretion of PICP. The α1(I) procollagen mRNA level was elevated with no effect on message stability, indicating a transcriptional mechanism of regulation. In contrast, dexamethasone treatment was accompanied by an accelerated rate of α1(I) procollagen mRNA turnover, observed as decreased amounts of the message and the secreted PICP, implying a posttranscriptional regulation. Retinoic acid, in turn, decreased the levels of α1(I) procollagen mRNA and secreted PICP by slowing down transcription of the COL1A1 gene without any effect on message stability. The ability of these hormones to regulate the α1(I) transcripts was sensitive to puromycin treatment, suggesting an involvement of an induced mediator protein in the action of the hormones on the COL1A1 gene. Both dexamethasone and calcitriol rapidly but transiently increased the expression of the c-fos and c-jun proto-oncogenes. Neither proto-oncogene responded to retinoic acid treatment with significant changes in mRNA levels. Estradiol treatment was found to have no influence on type I procollagen synthesis.In SaOs-2 cells, which are not as well differentiated as the MG-63 cells, calcitriol and dexamethasone did not influence type I procollagen synthesis. Retinoic acid as well as estradiol reduced collagen gene expression in these cells.These findings suggest that hormonal effects on type I procollagen synthesis may depend on the maturational state of the osteoblastic cells that express different regulatory factors and receptors, resulting in, in each case, a finely adjusted rate of gene expression. J. Cell. Biochem. 68:151-163, 1998. © 1998 Wiley-Liss, Inc.
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  • 91
    ISSN: 0730-2312
    Keywords: osteoprogenitors ; marrow-stroma ; alkaline phosphatase ; bisphosphonates ; cell proliferation ; mineralization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Bisphosphonates (BPs) are inhibitors of bone resorption and soft tissue calcification. The biological effects of the BPs in calcium-related disorders are attributed mainly to their incorporation in bone, enabling direct interaction with osteoclasts and/or osteoblasts through a variety of biochemical pathways. Structural differences account for the considerable differences in the pharmacological activity of BPs. We compared the effects of two structurally different compounds, alendronate and 2-(3′-dimethylaminopyrazinio)ethylidene-1,1-bisphosphonic acid betaine (VS-6), in an osteoprogenitor differentiation system. The BPs were examined in a bone marrow stromal-cell culture system, which normally results in osteoprogenitor differentiation. The drugs were present in the cultures from days 2 to 11 of osteogenic stimulation, a period estimated as being comparable to the end of proliferation and the matrix-maturation stages. We found that the two different BPs have opposing effects on specific alkaline phosphatase (ALP) activity, on stromal-cell proliferation, and on cell-mediated mineralization. These BPs differentially interact with cell-associated phosphohydrolysis, particularly at a concentration of 10-2 of ALP Km, in which alendronate inhibits whereas VS-6 did not inhibit phosphatase activity. VS-6 treatment resulted in similar and significantly increased mineralization at 10 and 1 μM drug concentrations, respectively. In contrast, mineralization was similar to control, and significantly decreased at 10 and 1 μM drug concentrations, respectively, under alendronate treatment. J. Cell. Biochem. 68:186-194, 1998. © 1998 Wiley-Liss, Inc.
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  • 92
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    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 200-212 
    ISSN: 0730-2312
    Keywords: polyamines ; chromatin structure ; micrococcal nuclease ; cell cycle ; apoptosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Several studies suggest that polyamines may stabilize chromatin and play a role in its structural alterations. In line with this idea, we found here by chromatin precipitation and micrococcal nuclease (MNase) digestion analyses, that spermidine and spermine stabilize or condense the nucleosomal organization of chromatin in vitro. We then investigated the possible physiological role of polyamines in the nucleosomal organization of chromatin during the cell cycle in Chinese hamster ovary (CHO) cells deficient in ornithine decarboxylase (ODC) activity. An extended polyamine deprivation (for 4 days) was found to arrest 70% of the odc- cells in S phase. MNase digestion analyses revealed that these cells have a highly loosened and destabilized nucleosomal organization. However, no marked difference in the chromatin structure was detected between the control and polyamine-depleted cells following the synchronization of the cells at the S-phase. We also show in synchronized cells that polyamine deprivation retards the traverse of the cells through the S phase already in the first cell cycle. Depletion of polyamines had no significant effect on the nucleosomal organization of chromatin in G1-early S. The polyamine-deprived cells were also capable of condensing the nucleosomal organization of chromatin in the S/G2 phase of the cell cycle. These data indicate that polyamines do not regulate the chromatin condensation state during the cell cycle, although they might have some stabilizing effect on the chromatin structure. Polyamines may, however, play an important role in the control of S-phase progression. J. Cell Biochem. 68:200-212, 1998. © 1998 Wiley-Liss, Inc.
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  • 93
    ISSN: 0730-2312
    Keywords: retinoic acid ; matrix metalloproteinases ; chondrocytes ; mRNA levels ; growth plate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling. In growth plate (GP) cartilage, extensive remodeling occurs at the calcification front. To study the potential involvement of MMPs in retinoic acid (RA) regulation of skeletal development, we studied the effect of all-trans-RA on MMPs levels in mineralizing chicken epiphyseal chondrocyte primary cultures. When treated for 4 day periods on days 10 and 17, RA increased levels of an ∼70 kDa gelatinase activity. The N-terminal sequence of the first 20 amino acid residues of the purified enzyme was identical to that deduced from chicken MMP-2 cDNA. Time-course studies indicated that RA elevated MMP-2 activity levels in the cultures within 16 h. This increase was inhibited by cycloheximide and was enhanced by forskolin. The increase in MMP-2 activity induced by RA was accompanied by an increase in MMP-2 mRNA levels and was abolished by treatment with cycloheximide. This upregulation of MMP levels by RA in GP chondrocytes is consistent with its effects on osteoblasts and osteosarcoma cells and opposite its inhibitory effects on fibroblasts and endothelial cells. It may well be related to the breakdown of the extracellular matrix in the GP and would be governed by the availability of RA at the calcification front where extensive vascularization also occurs. J. Cell. Biochem. 68:90-99, 1998. © 1998 Wiley-Liss, Inc.
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  • 94
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 287-297 
    ISSN: 0730-2312
    Keywords: aorta ; mineralization ; calcification ; hydroxyapatite ; inhibitors ; arteriosclerosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Mineralization of aorta is known to occur late in life and appears to be a pathological phenomenon. In vitro studies revealed that the matrix prepared from the thoracic aorta pieces after their extraction with 3% Na2HPO4 and 0.1 mM CaCl2 were mineralized under physiological conditions of temperature, pH, and ionic strength of the media to form matrix-bound mineral phase resembling hydroxyapatite in nature. However, the matrix identically prepared from the unextracted rabbits aortae failed to mineralize under identical assay conditions. The addition of the aorta extract in the assay system inhibited the above mineralization process. Standard biochemical techniques, e.g., dialysis, ion exchange, and molecular sieve chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and amino acid analysis by high-performance liquid chromatography were employed to isolate, purify, and characterize the potent inhibitory biomolecules from the aorta extract. The inhibitory activity of the aorta extract was found to be primarily due to the presence of three biomolecules having molecular weights of 66, 45, and 27-29 kDa. The above inhibitory biomolecules loosely associated with aorta may be involved in the control of calcification associated with arteriosclerosis. J. Cell. Biochem. 68:287-297, 1998. © 1998 Wiley-Liss, Inc.
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  • 95
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 309-327 
    ISSN: 0730-2312
    Keywords: in vitro replication ; ors8 ; Oct-1 transcription factor ; POU domain ; mammalian autonomously replicating DNA sequence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A 186-base pair fragment of ors8, a mammalian autonomously replicating DNA sequence isolated by extrusion of nascent monkey DNA in early S phase, has previously been identified as the minimal sequence required for replication function in vitro and in vivo. This 186-base pair fragment contains, among other sequence characteristics, an imperfect consensus binding site for the ubiquitous transcription factor Oct-1. We have investigated the role of Oct-1 protein in the in vitro replication of this mammalian origin. Depletion of the endogenous Oct-1 protein, by inclusion of an oligonucleotide comprising the Oct-1 binding site, inhibited the in vitro replication of p186 to approximately 15-20% of the control, whereas a mutated Oct-1 and a nonspecific oligonucleotide had no effect. Furthermore, immunodepletion of the Oct-1 protein from the HeLa cell extracts by addition of an anti-POU antibody to the in vitro replication reactioninhibited p186 replication to 25% of control levels. This inhibition of replication could be partially reversed to 50-65% of control levels, a two- to threefold increase, upon the addition of exogenous Oct-1 POU domain protein.Site-directed mutagenesis of the octamer binding site in p186 resulted in a mutant clone, p186-MutOct, which abolished Oct-1 binding but was still able to replicate as efficiently as the wild-type p186. The results suggest that Oct-1 protein is an enhancing component in the in vitro replication of p186 but that its effect on replication is not caused through direct binding to the octamer motif. J. Cell. Biochem. 68:309-327, 1998. © 1998 Wiley-Liss, Inc.
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  • 96
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 164-173 
    ISSN: 0730-2312
    Keywords: melittin ; flow cytometry ; cytotoxicity ; immunotoxin ; HMy2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have examined the cytolytic effects of the membrane-active peptide, melittin, on a human lymphoblastoid cell line (HMy2) in the context of the use of melittin as the toxic component of an immunotoxin. The toxicity of melittin for HMy2 cells was linear over the concentration range 0.875-3.5 μM. Increased incubation times failed to result in significant cell death at concentrations of melittin below 0.875 μM. Kinetic analysis revealed that the cytolytic activity of melittin was independent of time of exposure beyond 90 min. Flow cytometric analysis of HMy2 cells incubated with FITC-labeled melittin demonstrated that the cells could incorporate up to 2.5 × 105 FITC-melittin molecules per cell with no reduction in viability. Extrapolation of this data indicates that 106 melittin molecules per cell are required for maximum cytotoxicity to HMy2 cells. Further analysis of HMy2 cells that incorporated melittin, but that remained viable, revealed that these cells were able to reduce the number of melittin molecules per cell over time. The data indicate a potential threshold value for the number of melittin molecules that may be required to be delivered to the cell surface in the form of an immunotoxin if effective selective cell death is to be achieved. J. Cell. Biochem. 68:164-173, 1998. © 1998 Wiley-Liss, Inc.
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  • 97
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 174-185 
    ISSN: 0730-2312
    Keywords: metallothionein ; isoform ; differential expression ; autoregulation ; Chinese hamster ovary cell ; cadmium-resistant cell ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Transcription regulation of metallothionein (MT) isoform promoters was investigated in Chinese hamster ovary (CHO) K1 and MT gene amplified, cadmium-resistant (CdR) cells. The transfected promoter of Chinese hamster MTI and MTII genes can be activated in both cell lines by stimulation with Cd or Zn ions, although no MT mRNA can be detected in CHO K1 cells after challenge with metal ions. Neither MT promoter used in this study can be activated by induction with dexamethasone, regardless of whether a sequence homologous to glucocorticoid responsive element is present. During induction by metal ions, differential promoter activities of the MT genes occurs in both CHO K1 and CdR cells where MTII promoter has a stronger activity than that of MTI. As indicated by a time course study in both cell lines, the relative induction ratios of both MTI and MTII promoters are similar at each time interval. This result is consistent with a differential transcriptional factor-promoter interaction for the two MT promoters. By using the CHO K1 and CdR cells as a model system, the occurrence of autoregulation for yeast CUP1 (MT) gene was examined in mammalian cells. Both MT promoters consistently show a lower basal activity but a higher induction ratio in CHO K1 than CdR cells; a result different from that of yeast CUP1 gene. When MTF-1 mRNA was examined, no difference in relative quantity was observed in CHO K1 and in CdR cells treated with metal ions or with metal ions absent. J. Cell. Biochem. 68:174-185, 1998. © 1998 Wiley-Liss, Inc.
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  • 98
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 195-199 
    ISSN: 0730-2312
    Keywords: 14-3-3 protein ; developmental regulation ; heart development ; Raf-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Human heart cDNA sequencing yielded a cDNA clone that is similar in DNA and amino acid sequences to that of mouse 14-3-3 ε isoform. The 6xHis-tagged H1433ε recombinant protein was expressed in Escherichia coli and its size was approximately 30 kDa. From Northern blot results with human multiple tissues, human skeletal muscle was found to have the highest level of h1433ε mRNA expression, whereas Northern blots of human cancer cell lines detected the highest mRNA level of h1433ε in colorectal adenocarcinoma SW480. The protein expression level of h1433ε and Raf-1 is found to be regulated coordinately during rat heart development, and their protein expression was highest from 14.5 to 16.5 days postcoitum. J. Cell. Biochem. 68:195-199, 1998. © 1998 Wiley-Liss, Inc.
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  • 99
    ISSN: 0730-2312
    Keywords: transforming growth factor-β ; tumor necrosis factor-α ; phospholipase A2 ; arachidonic acid ; AACOCF3 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The steroid derivative 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a regulator of bone biology, and there is evidence that 1,25(OH)2D3 modulates arachidonic acid metabolism in osteoblastic cell model systems and in bone organ cultures. In the present studies, 1,25(OH)2D3 decreased prostaglandin (PG) biosynthesis by normal adult human osteoblast-like (hOB) cell cultures by about 30%. The decrease was observed under basal incubation conditions, or in specimens stimulated by transforming growth factor-β1 (TGF-β) or by tumor necrosis factor-α (TNF). The inhibition of the TGF-β-stimulated PG production appeared to reflect a diminished efficiency of arachidonic acid conversion into PGs by the cells, while the efficiency of substrate utilization for PG biosynthesis was unaffected by 1,25(OH)2D3 pretreatment in the unstimulated samples, or in samples stimulated with TNF or with TNF plus TGF-β. Free arachidonic acid levels were decreased following 1,25(OH)2D3 pretreatment in the TNF stimulated samples. hOB cell phospholipase A2 activity was measured in subcellular fractions, and this activity was decreased by 20-25% in the 1,25(OH)2D3 pretreated samples. The addition of the selective inhibitor AACOCF3 to the phospholipase A2 assays provided evidence that it was the cytoplasmic isoform of the enzyme that was affected by the 1,25(OH)2D3 pretreatment of the hOB cells. Thus, 1,25(OH)2D3 regulation of hOB cell biology includes significant effects on arachidonic acid metabolism. In turn, this could influence the effects of other hormones and cytokines whose actions include the stimulated production of bioactive arachidonic acid metabolites. J. Cell. Biochem. 68:237-246, 1998. © 1998 Wiley-Liss, Inc.
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  • 100
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    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 68 (1998), S. 436-445 
    ISSN: 0730-2312
    Keywords: mouse ; PDI family proteins ; retinoic acid ; dibutyryl cAMP ; differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We investigated the expression of protein disulfide isomerase family proteins (PDI, ERp61, and ERp72) in mouse F9 teratocarcinoma cells during differentiation induced by treatment with retinoic acid and dibutyryl cAMP. Each member of this family was expressed at a constitutive level in undifferentiated F9 cells. During differentiation of F9 cells to parietal or visceral endodermal cells the protein level of all these enzymes increased, although the extent of this increase in both protein and mRNA levels varied among the enzymes. Certain proteins were found to be co-immunoprecipitated with PDI, ERp61, and ERp72 in the presence of a chemical crosslinker. Type IV collagen was significantly coprecipitated with PDI whereas laminin was equally coprecipitated with the three proteins. Furthermore, 210 kDa protein characteristically coprecipitated with ERp72. Thus, the induction of PDI family proteins during the differentiation of F9 cells and their association with different proteins may implicate specific functions of each member of this family despite the common redox activity capable of catalyzing the disulfide bond formation. J. Cell. Biochem. 68:436-445, 1998. © 1998 Wiley-Liss, Inc.
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