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  • 1
    Digitale Medien
    Digitale Medien
    Ontogenetic change in the relationship between metabolic rate and body mass in a sea bream Pagrus major (Temminck & Schlegel) (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 38 (1991), S. 0 
    Details
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Ontogenetic changes in the relationship between resting rate of oxygen consumption and wet body mass were examined at 20° C with the sea bream Pagrus major ranging from 0.00020 g (weight just after hatching) to 270 g (weight at 530 days old). There was a triphasic relationship between oxygen consumption of an individual fish M (μl min−1) and body mass W(g). During a very early stage (weight 0.00020–0.00025 g), corresponding to the pre-larval stage and with the transitional period to the post-larval stage, there was no substantial change in body mass. The mass–specific metabolic rate M/W (μl g−1 min 1) showed no clear relationship to body mass as expressed by the equation M/ W=4.86 + 1.47 D, where D is age in days. During the post-larval stage (weight 0.00031–0.005 g), M/W remained almost constant independent of body mass following the expression M= 12.5 W0.949. During the juvenile and later stages (weight 0.005–270 g), M/ W decreased with increasing body mass following the expression M= 6.3 W0.821 which is significantly different from the expression for the post-larval stage (P 〈 0.001). Ontogenetic changes in the metabolism-body mass relationship are discussed from the viewpoint of relative growth of organs with different metabolic activities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1095-8649.1991.tb03136.x
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  • 2
    Digitale Medien
    Digitale Medien
    Effects of amino acid replacements on cadmium binding of metallothionein α-fragment (1997)
    Springer
    Cellular and molecular life sciences 53 (1997), S. 459-465 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Key words. Cadmium; cysteine; Escherichia coli; expression; metal; amino acid replacement; α-fragment; metallothionein.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. To evaluate whether only 20 cysteine residues at invariant positions are needed to bind and coordinate the metals in metallothioneins (MTs), and whether changing the positions of cysteine residues in the sequence affects the metal-binding capacity and the coordination of MTs, we examined the cadmium-binding affinities of seven mutant MTαs using an Escherichia coli expression system. Five mutant MTαs in which the constitutive amino acid residues other than cysteines of the α-fragment were replaced with glycine residues, and the remaining two mutant MTαs in which the invariant positions of the cysteine residues of the α-fragment were shifted, were analysed for their ability to be expressed as cadmium-binding forms and for their biochemical properties. The results showed that extreme alteration of the constitutive amino acid residues other than cysteines in the MT α-fragment leads to disruption of their cadmium-binding abilities and of their structure. However, mutant MTαs containing changes of the invariant positions of the cysteine residues were expressed in a cadmium-binding form in Escherichia coli, although the invariant positions of 20 cysteine residues in the MTs are thought to be important for their metal-binding abilities. These results suggest that the position of cysteine residues and the chemical nature of the other amino acids in the amino acid sequence of MTs are less critical than expected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s000180050056
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  • 3
    Digitale Medien
    Digitale Medien
    Decreased Serum Lecithin:Cholesterol Acyltransferase Activity in Spontaneous Cases of Fatty Liver in Cows (1997)
    Springer
    Veterinary research communications 21 (1997), S. 1-8 
    Details
    ISSN: 1573-7446
    Schlagwort(e): cattle ; cholesteryl esters ; fatty liver ; lecithin:cholesterol acyltransferase ; lipoprotein ; phosphatidylcholine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Nakagawa, H., Oikawa, S., Oohashi, T. and Katoh, N., 1997. Decreased serum lecithin:cholesterol acyltransferase activity in spontaneous cases of fatty liver in cows. Veterinary Research Communications, 21 (1), 1-8. Lecithin:cholesterol acyltransferase (LCAT) activity in serum was evaluated in spontaneous cases of fatty liver in cows. The enzyme activity of 631 ± 62 U (mean ± SEM, decrease in nmol of free cholesterol per h per ml of serum) in cows with fatty liver (n = 16) was significantly (p 〈 0.01) lower than that in cows without fatty liver (979 ± 22 U; n = 16). In addition to the decrease in LCAT activity, the concentrations of phosphatidylcholine (a fatty aryl donor for esterification of free cholesterol) and of cholesteryl esters (products of the LCAT reaction) were reduced in the high-density lipoprotein fractions from cows with fatty livers. The concentration in the serum of apolipoprotein A-I, an activator of LCAT, was also reduced in cows with fatty livers. These results suggest that the decreased LCAT activity, which may be attributable to impaired hepatic secretion or to the suppression of the activity in the plasma by reduced concentrations of phosphatidylcholine and apolipoprotein A-I, resulted in the lower concentrations of cholesteryl esters. Because cholesteryl esters are utilized in steroidogenic tissues for the synthesis of steroid hormones such as progesterone and glucocorticoids, an insufficient supply of the cholesterols may be of relevance to the reduced fertility and immune competence observed in cows with fatty livers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/B:VERC.0000009695.02015.20
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  • 4
    Digitale Medien
    Digitale Medien
    Measurements of99Tc,137Cs,237Np, Pu isotopes and241Am in sediment cores from intertidal coastal and estuarine regions in the Irish Sea (1999)
    Springer
    Journal of radioanalytical and nuclear chemistry 240 (1999), S. 593-601 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract Long-lived radionuclides,99Tc,137Cs,237Np, Pu isotopes and241Am were determined in the long sediment cores collected from nine intertidal sites around the west Cumbria of the Irish Sea, UK. The inventories of all nuclides measured varied considerably among the sampling sites, but generally their inventories decreased with increasing distance from Sellafield. Furthermore, the inventory ratios with respect to relationship with distance from Sellafield enabled comparison of transport behavior of99Tc,137Cs,237Np and241Am compared with239,240Pu. As a consequence, the apparent fractional rate of solution transport to the intertidal sediment was found to increase as follows:99Tc〉137Cs〉237Np〉239,240Pu≥241Am.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02349419
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