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  • Adult rats  (1)
  • Bioprocess development  (1)
  • biological neutralization  (1)
  • 1995-1999  (3)
  • 1
    ISSN: 1573-675X
    Keywords: Adult rats ; apoptosis without DNA fragmentation ; differentiation ; Schwann cells derived from wallerian-degenerated nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The Schwann cell cables provide particularly favorable sites for the growth of regenerating axonal sprouts. However, if they remain denervated, endoneurial fibrosis takes place with the Schwann cells atrophying and total Schwann cell number gradually decrease with time. Even when regenerating axonal sprouts invade into the cables, Schwann cells do not survive for long periods if they fail to make axonal contact. These observations strongly suggest the involvement of apoptosis in peripheral nerve degeneration and regeneration. So, we investigated the behavior of Schwann cells prepared from walleriandegenerated adult rat sciatic nerve in vitro. The secondary cultured Schwann cells showed serial changes in morphology, mitotic activity and migratory activity as they do during Schwann cell cable formation in vivo. At the final stage of differentiation, the Schwann cells became rounded and detached from the flask with extensive blebbing. Electron micrographs clearly demonstrated typical cytoplasmic changes of apoptosis, but, nuclei of most of the cells retained their size and morphology with residual nucleolar structures. An agarose gel electrophoresis of DNA clearly demonstrated that there was not any DNA fragmentation up to 120 h after detachment. Results by in situ apoptosis detection assay did not show any DNA degradation despite the substantial decrease in Schwann cell number. In conclusion, during peripheral nerve degeneration and regeneration, supernumerary Schwann cells are removed by apoptosis, however, it lacks most of the nuclear events of usual apoptosis.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 11 (1995), S. 461-467 
    ISSN: 1573-0972
    Keywords: Bioprocess development ; bioreactor optimization ; environmental factors ; modelling ; monitoring ; control ; plant cell culture ; secondary-metabolite production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Two key issues in the application of plant-cell-culture technology to the production of valuable secondary metabolites are reviewed: the selection of cell lines with suitable genetic, biochemical and physiological characteristics; and the optimization of bioreactor environments. Although great progress has been made in recent years in the design, selection and optimization of bioreactor hardware, optimization of environmental factors such as medium components, light irradiation and O2 supply needs detailed investigations for each case. With a better understanding of plant cell metabolism and physiology, further developments in cultivation processes, such as process integration and on-line monitoring and control, can be expected in the near future.
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  • 3
    ISSN: 1573-5036
    Keywords: acid deposition ; biological neutralization ; dwarf bamboo (Sasa) ; forest floor vegetation ; soil acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Adjacent plots (1 m2) with and without communities of dwarf bamboo (Sasa), i.e. Sasa- and ref-plots, were selected in mountainous areas, which were relatively low in soil buffer capacity. The following parameters were studied: chemical properties of surface (0-30 cm) soil (at 6 sites), elemental abundances in the soil-Sasa ecosystem (at 6 sites), effect of artificial acid rain on the above two parameters (at 1 site), and chemical properties of throughfall and stemflow of Sasa (at 2 sites including one on a plain). Average values of pH(H2O), base saturation and the ratio of exchangeable (K+Mg+Ca)/exchangeable Al in surface soil were 4.35±0. 53, 25.2±14.3% and 0.41±0.28, respectively, in Sasa-plots and 4.26±0.63, 20.0±9.6%, and 0.28±0.13, respectively, in ref-plots. Though not significant, all soil parameters had higher values in Sasa-plots, i.e. Δx = ca. 0.1 unit, 5% and 0.13, respectively. When the abundance of elements (exchangeable cations in soil of 30 cm depth plus elements in litter and Sasa biomass) in the ecosystem was compared between the two plots, K (and often other basic cations) was higher in Sasa-plots than in ref-plots, whereas Al was lower. Artificial acid rain (1.5 L of 0.05 M H2SO4 applied monthly for 10 months) induced a reduction of Na, K, Mg and Ca in a ref-plot, but in a Sasa-plot only Na and K were reduced whereas Mg and Ca were completely retained. The composite samples of throughfall and stemflow of Sasa were ca. 0.5 higher in pH and richer in K, Mg and Ca than the ambient precipitation. The amounts (equivalents) of elements released by Sasa were in the order K 〉 Ca 〉 Mg. It was determined that about 87% and 98% of K, 76% and 87% of Ca, and 39% and 93% of Mg were of Sasa origin in the composite samples at a mountainous site (cambisol soil type) and a plain site (andosol soil type), respectively. Sasa communities may have a significant role in retention of basic cations in surface soil and prevention of soil acidification because of recycling elements in the soil-Sasa ecosystem.
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