Carbon and nitrogen starvation

Carbon and Nitrogen Starvation. Carbon and nitrogen starvation affect LiP and MnP production in different manna s. As is shown in Fig. 2, carbon starvation leads... 

Under nitrogen starvation starch and oil content are increased. This is considered in model finking carbon and nitrogen flux. 

In a useful review of dietary standards, Leitch (1942) ascribes to a certain Dr. E. Smith in England the first statement of dietary requirements. The critical situation was a cotton famine and widespread unemployment among English cotton workers. The purpose of the resulting standard was to avert starvation diseases, and the figures were in terms of carbon and nitrogen. 

Cook, C. B., MuUerparker, G., and D Elia, C. F. (1992). Ammonium enhancement of dark carbon fixation and nitrogen limitation in symbiotic zooxantheUae—Effects of feeding and starvation of the sea-anemone aiptasia-paUida. Limnol. Oceanogr. 37(1), 131—139. 

Fig. 3 Electron micrographs of thin sections of A. brasilense 1030 (a) and the p/taZ mutant (b), grown for 48 h in high carbon to nitrogen medium, and of A. brasilense 7030 (c) and the phaZ mutant (d) following a 72-h starvation period in phosphate buffer. Arrows indicates PHB granules, bars, 1 pm. Thirty sections of each strain were examined and showed identical findings (Reproduced from Kadouri et al. (2003a), with permission of Springer-Verlag)...

The alanine cycle accomplishes the same thing as the Cori cycle, except with an add-on feature (Fig. 17-11). Under conditions under which muscle is degrading protein (fasting, starvation, exhaustion), muscle must get rid of excess carbon waste (lactate and pyruvate) but also nitrogen waste from the metabolism of amino acids. Muscle (and other tissues) removes amino groups from amino acids by transamination with a 2-keto acid such as pyruvate (oxaloacetate is the other common 2-keto acid). 

Reviews by Ruderman (19) and Adibi (20,21) indicate that the branched-chain amino acids, particularly leucine, have an important role along with alanine in gluconeogenesis. Leucine and the other two branched-chain amino acids are catabolized in skeletal muscle. The nitrogen that is removed from the branched-chain amino acids in skeletal muscle is combined with pyruvate and returned to the liver as alanine. In the liver the nitrogen is removed for urea production and the carbon chain is utilized as substrate for synthesis of glucose. Adibi et al. (22) reported that during the catabolic conditions of starvation, oxidation of leucine and fatty acids increases in skeletal muscles. While glucose oxidation is reduced, the capacity for oxidation of the fatty acid palmltate more than doubled, and leucine oxidation increased by a factor of six. 

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