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Symbiotic Interactions between Colonic Microflora and Protein Metabolism in Infants
Author(s) -
HEINE W.,
MOHR C.,
WUTZKE K. D.,
RADKE M.
Publication year - 1991
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1991.tb11722.x
Subject(s) - feces , excretion , urine , absorption (acoustics) , urea , metabolism , trichloroacetic acid , medicine , cystine , endocrinology , chromatography , zoology , chemistry , biochemistry , biology , microbiology and biotechnology , cysteine , enzyme , physics , acoustics
. The utilization of 15 N nitrogen from 15 N‐labelled bifidobacteria for whole body protein synthesis was studied in 4 infants by oral single‐pulse labellings and in 3 other infants, who had colostomies, by colonic pulse labellings. The bifidobacteria were harvested from a modified Petuely culture medium containing 15 N ammonium chloride and 15 N cystine as the only sources of nitrogen. The tracer dose chosen for the balance studies was 3 mg 15 N/kg. 15 N concentrations in urine and feces collected over 48 hours after the pulse labellings were determined by emission spectrometry. Oral administration of 15 N‐labelled bifidobacteria resulted in absorption of approximately 90%, renal excretion of 15%, and fecal excretion of 12% of the tracer dose, respectively. Retention in the protein pool averaged 73%. After colonic single pulse labelling with 15 N‐labelled bifidobacteria, the corresponding values were 85.5%, 2.2%, 14.5%, and 83.0%, respectively. Absorption and incorporation of the heavy nitrogen into body proteins were directly demonstrated by increased 15 N atom percent excess values within the trichloroacetic acid (TCA) supernatants and the proteins of the plasma, 0.25 and 0.04 atom %, respectively, at 24 hours after oral pulse labellings. One half of the total 15 N excreted in urine consisted of urea and approximately 8% was eliminated as ammonia.