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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 43 (1987), S. 410-412 
    ISSN: 1420-9071
    Schlagwort(e): Serotonin ; 5-hydroxytryptamine ; tetanus toxin ; pargyline ; alphamethyldopa ; indolamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform thoughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Meiotic and karyotypic analyses of six populations of two closely related species belonging to the section Eusideritis of the genus Sideritis (five of S. saetabensis and one of S. tragoriganum) (Lamiaceae), revealed polymorphisms for asymmetric reciprocal translocations. Two populations of S. saetabensis (S-046 and S-089) and the population of S. tragoriganum (S-056) contained heterozygotes and standard homozygotes. No homozygotes for the rearrangement (dicentric) were found. The meiotic behavior of the heterozygotes showed great stability of the dicentric chromosomes in both species due to strict control of meiosis at three levels: (1) chiasma formation, (2) multivalent coorientation at metaphase I, (3) dicentric chromatid separation at anaphase II. During mitosis there may also be strict control of dicentric chromatid separation through 100% parallel separation without interlocking. This stable polymorphism for asymmetric reciprocal translocations is a unique phenomenon that seems to be maintained by over-dominance, thus being a special case of linkage disequilibrium. We give two alternative hypotheses to explain the origin of these polymorphisms and discuss their evolutionary significance.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Histochemistry and cell biology 99 (1993), S. 453-456 
    ISSN: 1432-119X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Although 6 bp-restriction endonucleases infrequently cut DNA, we describe in this paper the banding pattern induced by one of them, StuI (AGGCCT), on fixed human chromosomes. This enzyme is the first 6 bp-restriction endonuclease demonstrated to be able to digest human heterochromatin. It causes the extraction of two families of repeated DNA, the alpha satellite DNA and the 3.4 kb HaeIII family (DYZ1). On the other hand, digestions with StuI and with another two enzymes, HinfI and RsaI, have established the distribution of sequences within the heterochromatic block of chromosome 3.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    ISSN: 1432-1793
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of solar radiation on photosynthetic oxygen production, pulse amplitude-modulated (PAM) fluorescence and pigmentation were measured in the Mediterranean brown macroalgaPadina pavonica (Linnaeus) Lamouroux under field conditions and natural sunlight. Exposure of thalli to solar radiation for 1 h caused a dramatic decrease of their photosynthetic quantum yield, which recovered to initial levels after they had been placed in the shade for 3 h. Photoinhibition also occurred at the natural growth site ofP. pavonica during the hours of maximal solar irradiance. Photosynthetic oxygen production was also affected by high levels of solar radiation both in algae harvested from the surface and from 6 m depth; oxygen production started to decrease after a few minutes of exposure, and negative values were found after 1 h of solar exposure. Chlorophylla content inP. pavonica also decreased during the hours of maximal solar irradiation. These results suggest that photoinhibition ofP. pavonica occurs during part of a typical summer day on Mediterranean coasts.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Bioprocess engineering 17 (1997), S. 317-322 
    ISSN: 0178-515X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Spores of the biocontrol agent Trichoderma harzianum P1 produced in liquid media and harvested in the stationary sporulation stage SSS (after 60 h), had higher viability after slow (〉4×) and fast drying (〉12×) than their counterparts harvested in the exponential sporulation stage, ESS (after 30 h). The trehalose content of SSS spores was almost 20× higher than that of ESS spores (0.16 vs. 3.4 mg/100 mg, respectively). Heat shock (40 °C × 90 min) effectively increased the trehalose content 2.5× with respect to untreated SSS spores. The trehalose content achieved in heat-treated SSS spores was almost 60% higher than the maximum reached by holding the spores under water-stress at 97% relative humidity prior to drying.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Bioprocess engineering 17 (1997), S. 177-183 
    ISSN: 0178-515X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Spores of the potential biocontrol agent Trichoderma harzianum P1 were prepared without (M1) and with heat shock (40 °C for 90 min) after fermentation (M2), filtered into a paste and dried over silica gel. M1 and M2 exhibited high viability (55%) and similar initial trehalose contents (4.0 and 5.4%, respectively) after slow drying. No significant differences in viability were found between treatments during storage for 110 days under different temperatures, T (8, 33 and 42 °C) and water activities, a w (0.03, 0.33 and 0.75). Viability of spores, after storage at a w =0.03 were 100 and 70% for 8 and 33 °C, respectively. During storage, decrease in trehalose content and viability was faster at a w =0.75 and 42 °C. Loss of viability was modeled by a first order kinetic model depending on 1/T and a w . M2 (with heat shock) showed slightly higher trehalose contents than M1 which resulted in 100% viability after 52 days at 8 °C.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    ISSN: 1573-6857
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nuclear DNA amount, nuclear area, genome volume and karyotype length were analysed in different populations of two closely related species of Narcissus. There are intra- and interspecific variations in these parameters. 4C DNA amount and karyotype length, on one hand, and 2C DNA amount and telophase nuclear area, on the other, are not correlated. It seems that DNA content and chromosome length are independent parameters. However, 4C DNA content and karyotype volume are correlated, and are also correlated to different density estimations (4C DNA to Kar.length & 2C DNA to telophase area). These facts suggest that the relative length of the chromosomes is genetically controlled and that it is independent of the DNA that they contain. It seems that the interpopulational differences in DNA content are correlated with length changes of small segments in almost all chromosomes.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    ISSN: 1573-6881
    Schlagwort(e): Plasma membrane ; liver ; ascorbate ; dehydrogenases ; clathrin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract Plasma membranes isolated from rat liver by two-phase partition exhibited dehydrogenase activities for ascorbate free radical (AFR) and ferricyanide reduction in a ratio of specific activities of 1 : 40. NADH-AFR reductase could not be solubilized by detergents from plasma membrane fractions. NADH-AFR reductase was inhibited in both clathrin-depleted membrane and membranes incubated with anti-clathrin antiserum. This activity was reconstituted in plasma membranes in proportion to the amount of clathrin-enriched supernatant added. NADH ferricyanide reductase was unaffected by both clathrin-depletion and antibody incubation and was fully solubilized by detergents. Also, wheat germ agglutinin only inhibited NADH-AFR reductase. The findings suggest that NADH-AFR reductase and NADH-ferricyanide reductase activities of plasma membrane represent different levels of the electron transport chain. The inability of the NADH-AFR reductase to survive detergent solubilization might indicate the involvement of more than one protein in the electron transport from NADH to the AFR but not to ferricyanide.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Neurochemical research 6 (1981), S. 893-900 
    ISSN: 1573-6903
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Mevalonate phosphorylation was studied in neonatal chick brain. Formation of phosphorylated derivatives of mevalonic acid increased with the pH in the range assayed (5.5–9.5). Phosphomevalonate kinase was completely inactivated after treatment at 50°C for 5–10 min, whereas mevalonate kinase was found to retain its activity under the same conditions. Exposure to 65°C for 5 min resulted in the inactivation of mevalonate kinase. Both mevalonate-activating enzymes from chick brain were located primarily in the soluble fraction. The amounts of phosphomevalonic acid and pyrophosphomevalonic acid did not show a significant diurnal variation to suggest the presence of a circadian rhythm in either kinase. Cholesterol feeding and fasting had no effect on mevalonate phosphorylation by neonatal chick brain.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    ISSN: 1573-6857
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have analyzed the pattern of AluI digestion over time on human chromosomes in order to monitor the evolution of the in situ enzyme action. Short treatments followed by Giemsa staining produce a G-like banding effect, whereas longer treatments produce a C-like banding pattern. However, when Propidium iodide staining is used, it reveals a uniform bright fluorescence after short AluI digestions and C bands when longer treatments are developed. We propose that C banding is the result of a uniform DNA removal in non centromeric regions taking place after a critical time point, the initial G like banding being produced by changes in the DNA-proteins interactions.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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