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  • Polymer and Materials Science  (19)
  • apoptosis  (6)
  • ionosphere  (3)
  • ELISA  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Biotinylated DNA probes for detecting virus Y and aucuba mosaic virus in leaves and dormant tubers of potato (1992)
    Springer
    Potato research 35 (1992), S. 173-182 
    Details
    ISSN: 1871-4528
    Keywords: non-radioactive probes ; RNA or DNA hybridization ; ELISA ; potato virus Y ; potato aucuba mosaic virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Detection of potato virus Y (PVY) in dormant potato tubers using the enzyme-linked immunosorbent assay (ELISA) has been reported not to be accurate and reliable and it requires breaking of the dormancy of tubers prior to testing. We describe a simple, practical and highly sensitive hybridization method based on the use of biotinylated DNA probes for detecting PVY and potato aucuba mosaic virus (PAMV) in dilutions made of crude extracts of infected potato leaves and dormant tubers. As little as 50 fg of RNA can be detected by this method, and the probes are highly specific for their targets, even in crude plant extracts. The presence of one virus did not interfere with the detection of the other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02357611
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  • 2
    Electronic Resource
    Electronic Resource
    New disease symptoms observed on field-grown potato plants with potato spindle tuber viroid and potato virus Y infections (1987)
    Springer
    Potato research 30 (1987), S. 127-133 
    Details
    ISSN: 1871-4528
    Keywords: Synergistic reaction ; necrotic symptoms ; virus concentration ; ELISA ; PAGE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Potato spindle tuber viroid (PSTV) and potato virus Y (PVY) were isolated from plants of cultivar Kennebec with severe necrotic symptoms in the field. In the greenhouse, severe necrotic symptoms were reproduced only when potato plants were infected either simultaneously with PSTV+PVY, or with PSTV prior to PVY infection. Thirteen additional potato cultivars were tested in the greenhouse for this synergistic reaction and eight developed necrotic responses similar to cv. Kennebec. PVY concentration was significantly higher in doubly infected plants, compared with those infected with PVY alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02357692
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of bcl-2 on antibody productivity in high cell density perfusion cultures of hybridoma (1999)
    Springer
    Cytotechnology 30 (1999), S. 95-106 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; Bcl-2 ; fixed-bed ; hollow fibre ; hybridoma ; perfusion ; protein-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Apoptosis is an active, genetically determined death mechanism which can be induced by a wide range of physiological factors and by mild stress. It is the predominant form of cell death during the production of antibodies from murine hybridoma cell lines. A number of studies have now demonstrated that the suppression of this death pathway, by means of over-expression of survival genes such as bcl-2, results in improved cellular robustness and antibody productivity during batch culture. In the present study, the influence of bcl-2 expression on hybridoma productivity in two high density perfusion bioreactor systems was investigated. In the first system, a fixed-bed reactor, the DNA content in the spent medium was 25% higher in the control (TB/C3-pEF) culture than that found in the bcl-2 transfected (TB/C3-bcl2) cultures at all perfusion rates. This is indicative of a higher level of cell death in the control cell line. The average antibody concentration for the TB/C3-pEF cell line was 14.9 mg L-1 at perfusion rates of 2.6 and 5.2 d-1. However, for the TB/C3-bcl2 cell line it was 33 mg L-1 at dilution rates of 2 and 4 d-1. A substantial increase in antibody concentration was also found in the Integra Tecnomouse hollow fibre reactor. The antibody titre in the TB/C3-bcl2 cassette was nearly 100% higher than that in the TB/C3-pEF cassette during the cultivation period which lasted 6 weeks. Clearly, these results demonstrate the positive impact of bcl-2 over-expression on production of antibody in hybridoma perfusion cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008055702079
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  • 4
    Electronic Resource
    Electronic Resource
    Variable functions of bcl-2 in mediating bioreactor stress- induced apoptosis in hybridoma cells (1998)
    Springer
    Cytotechnology 28 (1998), S. 177-188 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; bcl-2 ; cell death ; hybridoma ; osmolarity ; pH ; shear ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract It has been demonstrated that the cell lines used for production of biopharmaceuticals are highly susceptible to apoptosis, and that over-expression of the bcl-2 oncogene can protect cells from death. Stress associated with the deprivation of nutrients has been shown to be the main cause of apoptosis in culture. We have extended these studies by investigating the mechanism of cell death under conditions of sub-optimal pH, shear stress and hyperosmolarity, and the protective action of bcl-2 over-expression. At pH 6, there was no clear evidence of protection from cell death. However, at pH 8, the viability of the bcl-2 transfected cells was about 20% higher relative to the control cells. Cultivation of control cells in a flat bottomed bioreactor with a magnetic stirrer bar without a pivot ring resulted in exposure of the cells to a high attrition effect. As a result, cell growth was retarded and a high level of cell death by apoptosis was observed. Under the same conditions, the bcl-2 transfected cell line exhibited a nearly five fold increase in viable cell number. This finding indicates that under apoptosis-suppressed conditions, shear stress can stimulate cell growth. Batch cultivation of both control and bcl-2 transfected cells in 350 and 400 mOsm media resulted in suppression of cell growth, athough the effect was most marked in the control cell line. Adaptation of control cells to 400 mOsm proved to be impossible to achieve. However, the bcl-2 transfected cells exhibited resistance to the osmotic stress resulting in long term adaptation to a high salt environment. Specific productivity of bcl-2 transfected cells grown in high osmolarity medium was 100% higher than that produced by non- adapted bcl-2 transfected cells grown in normal osmolarity medium. These results demonstrate that bcl-2 has a beneficial effect on hybridoma cultivation under a wide range of culture stresses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008002319400
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  • 5
    Electronic Resource
    Electronic Resource
    Day time observations of precursors at low latitude (1996)
    Springer
    Earth, moon and planets 73 (1996), S. 267-275 
    Details
    ISSN: 1573-0794
    Keywords: Earth atmosphere ; ionosphere ; whistlers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Whistler precursors observed during day time at low latitude ground station Gulmarg (Geomag. Lat. 24
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115885
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  • 6
    Electronic Resource
    Electronic Resource
    Propagational features of higher harmonic tweeks at low latitudes (1996)
    Springer
    Earth, moon and planets 73 (1996), S. 277-290 
    Details
    ISSN: 1573-0794
    Keywords: Earth atmosphere ; ionosphere ; whistlers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Higher harmonic tweeks observed for the first time at the low latitude station Varanasi (geomag. lat. 14
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115886
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  • 7
    Electronic Resource
    Electronic Resource
    Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude (1996)
    Springer
    Earth, moon and planets 74 (1996), S. 7-15 
    Details
    ISSN: 1573-0794
    Keywords: atmospheric plasma ; ionosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Observations of whistlers during quiet times made at low-latitude ground station Nainital (geomag. lat. 19
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00118718
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  • 8
    Electronic Resource
    Electronic Resource
    Drag reduction by polymer-polymer mixtures (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 837-858 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An extensive study on the turbulent drag reduction caused by the various mixtures of polyacrylamide, purified guargum, xanthangum, and their graft copolymers has been conducted at low concentrations and Re = 14,000 using a turbulent flow rheometer. It has been found in most of the cases that the drag reduction caused by mixtures shows a positive deviation from the linearly additive straight line. This effect is more prominent when the drag reduction caused by both the constituents differ appreciably. In most of the cases, the drag reduction caused by the mixtures is higher than the DR caused by either of the constituent polymers; however, the drag reduction caused by the mixture is less than the sum of the drag reduction caused by both the constituents at their respective concentration in the mixture. It has also been noticed that there is no evidence of synergism in these mixtures at low concentrations.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360409
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  • 9
    Electronic Resource
    Electronic Resource
    Photo- and thermoinitiated oxidation of high-impact polystyrene.N.C.L. Communication No. 5688. I. Characterization by FT-IR spectroscopy (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 485-493 
    Details
    ISSN: 0887-624X
    Keywords: photooxidation ; thermal-oxidation, high-impact ; polystyrene ; FT-IR spectroscopy ; derivatization reaction ; oxidation profile ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photo- and thermooxidative degradation of different grades of high-impact polystyrene (HIPS) has been studied by FT-IR spectroscopy. The oxidized films were treated with NH3 and SF4 for the rapid identification and resolution of the various carbonyl species, alcohols, and hydroperoxides. All the sample gave similar oxidation products, but in varying quantities. The heterogenity in the film was also determined by micro-FT-IR spectroscopy. The thermal degradation processes at different temperature were compared. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320310
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  • 10
    Electronic Resource
    Electronic Resource
    Cell death in bioreactors: A role for apoptosis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 720-726 
    Details
    ISSN: 0006-3592
    Keywords: cell death ; apoptosis ; hybridoma cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The incidence of apoptotic and necrotic cell death was compared in CHO, SF9 insect cells and murine plasmacytoma (J558L) and hybridoma (TB/C3) cells during in vitro cultivation in batch cultures. Acridine orange staining and fluorescence microscopy enabled the visualization of a classic morphological feature of apoptotic cell, the presence of condensed and/or fragmented chromatin. DNA gel electrophoresis was employed to show an additional characteristic of the process, the endonuclease-mediated fragmentation of DNA into multiples of 180 base pairs. The levels of apoptosis at the end of batch cultures of plasmacytoma and hybridoma cell lines were found to be 60% and 90% of total dead cells, respectively. However, employing the above-mentioned techniques, the biochemical and morphological features of apoptosis were not found in CHO and SF9 insect cells. Some factors affecting the induction of apoptosis during the batch culture of the hybridoma and plasmacytoma cell lines were identified. The most effective inducer was found to be glutamine limitation, followed by (in order of importance) serum limitation, glucose limitation, and ammonia toxicity. Blockage of the cell cycle of the plasmacytoma and hybridoma cells using thymidine resulted in the induction of apoptosis. This has important implications for the development of cell culture processes that minimize cell division and thereby increase specific productivity. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260440608
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