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  • Biochemistry and Biotechnology  (1)
  • Cadmium  (1)
  • Caudate-Cholinergic Mechanism  (1)
  • 1
    ISSN: 1432-0789
    Keywords: Nicotiana tabacum L. ; Nicotiana rustica L. ; Zea mays L. ; Cadmium ; Bioavailability ; Phytotoxicity ; Pollution ; Translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mature (flowering) tobacco (Nicotiana tabacum cv. PBD6, Nicotiana rustica cv. Brasilia) and maize (Zea mays cv. INRA 260) plants were grown in an acid sandy-clay soil, enriched to 5.4 mg Cd kg−1 dry weight soil with cadmium nitrate. The plants were grown in containers in the open air. No visible symptoms of Cd toxicity developed on plant shoots over the 2-month growing period. Dry-matter yields showed that while the Nicotiana spp. were unaffected by the Cd application the yield of Z. mays decreased by 21%. Cd accumulation and distribution in leaves, stems and roots were examined. In the control treatment (0.44 mg Cd kg−1 dry weight soil), plant Cd levels ranged from 0.4 to 6.8 mg kg−1 dry weight depending on plant species and plant parts. Soil Cd enrichment invariably increased the Cd concentrations in plant parts, which varied from 10.1 to 164 mg kg−1 dry weight. The maximum Cd concentrations occurred in the leaves of N. tabacum. In N. rustica 75% of the total Cd taken up by the plant was transported to the leaves, and 81% for N. tabacum irrespective of the Cd level in the soil. In contrast, the Cd concentrations in maize roots were almost five times higher than those in the leaves. More than 50% of the total Cd taken up by maize was retained in the roots at both soil Cd levels. The Cd level in N. tabacum leaves was 1.5 and 2 times higher at the low and high Cd soil level, respectively, than that in N. rustica leaves, but no significant difference was found in root Cd concentrations between the two Nicotiana spp. Cd bioavailability was calculated as the ratio of the Cd level in the control plants to that in the soil or as the ratio of the additional Cd taken up from cadmium nitrate to the amount of Cd applied. The results showed that the plant species used can be ranked in a decreasing order as follows: N. tabacum 〉 N. rustica 〉 Z. mays.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Cholinergic-Mechanisms ; Instrumental Conditioning ; Caudate-Cholinergic Mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two series of experiments were performed in cats in which 80 Μg of atropine in 5 Μl were injected into the head of both caudate nuclei. In order to obtain a reward (a constant amount of milk) the first group of Ss learned to walk a distance of 75 cm after the delivery of 4 flashes, while the second group learned to press a lever. Both tasks were significantly impaired (P〈0.05) after atropine injection. The motor reflex response as well as hunger motivation were not modified by the substance. A caudate-cholinergic mechanism involved in the maintenance of motor conditioned responses is proposed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 61 (1994), S. 167-173 
    ISSN: 0268-2575
    Keywords: microalga ; growth model ; light-limitation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model for light-limited growth of a continuous microalgal culture is proposed. Average light intensity inside the photobioreactor was calculated, taking light attenuation by algae into account. The biomass absorption coefficient was determined by means of two new parameters, the pigment-free biomass, YB, and the total pigment absorption, Yp (absorption coefficient normalized to total pigment content). The model reproduced the steady states reached and the dynamic behaviour of the system when the dilution rate was changed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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