EFFECT OF MATURITY OF ALFALFA (Medicago sativa) AT HARVEST ON CALCIUM ABSORPTION IN GOATS

1989 ◽  
Vol 69 (2) ◽  
pp. 365-371 ◽  
Author(s):  
A. H. FREDEEN
Keyword(s):  
Key Words ◽  
Isotope Dilution ◽  
Calcium Absorption ◽  
Control Diet ◽  
Dilution Technique ◽  
Full Bloom ◽  
Isotope Dilution Technique ◽  
Total Diet ◽  
Bone Calcium ◽  
Accretion Rates

Alfalfa hay harvested at vegetative or full bloom stages of maturity was compared to a control diet, in which the calcium (Ca) source was mainly limestone. True Ca absorption was determined using an isotope dilution technique in three goats fed Ca at requirement. Mean Ca intakes of goats fed the control, vegetative or full bloom alfalfa were: 2.40 ± 0.405, 2.31 ± 0.393 and 2.47 ± 0.461 g d−1; bone calcium accretion rates were: 1.27 ± 0.294, 0.90 ± 0.319 and 1.21 ± 0.237 g d−1; total Ca absorption rates (percent of intake) were: 57.1 ± 2.46, 56.7 ± 8.07 and 54.3 ± 3.03, respectively. Although no differences in true Ca absorption among diets were observed in goats fed Ca at requirement, absorption rates exceeded 50% of intake and are higher than previous estimates. Maturity of alfalfa did not significantly affect Ca availability, although there was a trend for availability to diminish with maturity when absorption rates were corrected for Ca absorbed from other dietary ingredients (i.e., 55.8% availability for vegetative, 47.0% for full-bloom alfalfa). Replacing limestone with alfalfa did not alter Ca bioavailability in the total diet. Key words: Goats, calcium true absorption, alfalfa, maturity, limestone.

O-Methylierung von Adrenalin, 3.4-Dihydroxybenzoesäure und 6.7-Dihydroxycumarin in Sproßpilzen /O-Methylation of Epinephrine, 3,4-Dihydroxybenzoic Acid and 6,7-Dihydroxycoumarin in Yeasts

1976 ◽  
Vol 31 (9-10) ◽  
pp. 509-513 ◽  
Author(s):  
D Müller-Enoch ◽  
H Thomas ◽  
W Streng ◽  
W Ildfeuer ◽  
O Haferkamp
Keyword(s):  
Enzyme Activity ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Isotope Dilution ◽  
Dihydroxybenzoic Acid ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Methyl Derivatives ◽  
Layer Chromatography ◽  
Methoxybenzoic Acid

Abstract In the yeasts C. albicans, C. tropicalis, and C. stellatoidea but not in C. krusei, R. rubra, and S. cerevisiae enzyme activity was found by which - as by the catechol-O-methyltransferase (EC 2.1.1.6) found in the liver - the O-methylation of epinephrine to metanephrine and paranephrine, of 3,4-dihydroxybenzoic acid to 4-hydroxy-3-methoxybenzoic acid and 3-hydroxy-4-methoxybenzoic acid, and of 6,7-dihydroxycoumarin to 7-hydroxy-6-methoxycoumarin and 6-hydroxy-7-methoxy-coumarin is catalysed. When the substrates 3,4-dihydroxybenzoic acid, or 6,7-dihydroxycoumarin or epinephrine were incubated in the presence of S-adenosyl-ʟ-[methyl-14C] methionine and S-adenosylmethionine hydrogensulfate with a 100 000 X g supernatant of C. albicans, C. tropicalis or C. stellatoidea the cor­responding O-methylethers were detected in the extracts of the incubation medium by thin-layer chromatography. Final identification of the isomeric radioactive O-methylethers obtained from 3,4-dihydroxy­ benzoic acid and 6,7-dihydroxycoumarin was performed after thin-layer chromatographic separation by the reversed isotope dilution technique. The radioactive m-and p-O-methyl derivatives from epinephrine were separated by thin-layer chromatography and then cleaved with periodate to the corresponding aldehydes which were also identified mainly by the reversed isotope dilution technique.

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