The Metabolism of Carbon Dioxide by Streptococcus bovis

Abstract

SUMMARY: Carbon dioxide stimulates the growth of Streptococcus bowis and the production of the ,extracellular enzyme dextransucrase. The growth of cultures in the presence of 14C0, resulted in the incorporation of carbon-14 into aspartic acid, with lesser amounts in threonine, glutamic acid, adenine, guanine, uridylic acid and cytidylic acid. Organisms grown with labelled aspartic acid did not utilize it to any extent; the principal source of this amino acid was from C0,-fixation reactions. The stimulation of growth by COa is considered to be due to biosynthetic reactions involving COa which lead to a sufficient supply of the intermediates required in nucleic acid and protein synthesis.

Metabolism of Peptides by Rumen Microorganisms

“…Although it is known that amino acids are readily converted by rumen microorganisms to carbon dioxide and volatile fatty acids (2,14), little is known about the transport of amino acids or peptides into rumen organisms. There is one report of a slow uptake of aspartic acid by Streptococcus bovis (12). The present results indicate that the peptides enter the microbial cells almost as rapidly as do the amino acids.…”

Caecal decomposition of uric acid in captive and free ranging willow ptarmigan (Lagopus lagopus lagopus)

“…Moss & Parkinson (1972 were unable to detect anv uric acid in the caeca of caDtive red (1936) proposed that incorporation of CO, into aspartic acid and glutamic acid occurs via a condensation reaction involving the synthesis of oxaloacetate from pyruvate and CO,. This was later supported by observations of Wright (1960) and Burchall et al (1964). Besides giving an explanation of low recovery in the present expts., the CO?…”

Biochemical Aspects of Morphogenesis in Algae and Fungi

“…Thus, morphogenic effects of CO2 on fungi have been found to be associated with drastic alterations in polysaccharide composition (5,24,33). Carbon dioxide appears to operate, not by being incorporated into poly saccharides, the synthesis of which is stimulated in the presence of CO2, (5,183), but by affecting the synthesis of enzymes concerned with polysac charide metabolism (24,34). The control effect of CO2 on metabolism is further evidenced by inhibition in vitro (by CO2 or HCOa-) of enzymes in volved in respiration (10,107,137) and CO2 assimilation (172,173).…”