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Metabolism of Schizotrypanum cruzi Chagas. II. Galactose Utilization

1963; American Society of Parasitologists; Volume: 49; Issue: 5 Linguagem: Inglês

10.2307/3275926

1937-2345

Lionel G. Warren, William B. Kitzman,

Research on Leishmaniasis Studies

The utilization of galactose by Schizotrypanum cruzi and the effect of the sugar upon S. cruzi respiration are a function of the galactose concentration employed. Kinetic analysis of galactose utilization indicates that an active process and a diffusion component are involved in the utilization of this sugar by S. cruzi. Q02/Q galactose ratios at different concentrations of galactose-show that utilization of the sugar increases disproportionately to the increase in respiration. The latter is probably a consequence of galactose incorporation into polysaccharide. Methods of harvesting and washing parasites prior to experimental measurements influence the levels of endogenous respiration observed in this organism. Galactose is poorly utilized or not utilized by Trypanosomatidae (von Brand, 1952). Fulton and Joyner (1949) reported that respiration of Leishmania donovani was stimulated by galactose about one-third as much as by glucose. Zeledon (1960) reported that respiration of Schizotrypanum cruzi was stimulated by galactose. Zeledon (1960) also observed a stimulating effect by galactose upon the respiration of Endotrypanum schaudinni, L. enriettii, and S. vespertilionis. All of the aforementioned genera are considered to be distinct from the genus Trypanosoma, or in the case of Schizotrypanum, the taxonomic status is not resolved. Goncalves and Yamaha (1959) reported that the culture form of S. cruzi contains an immune polysaccharide which upon hydrolysis yields galactose as the principal monosaccharide. Von Brand et al. (1959) reported a polysaccharide from S. cruzi which on hydrolysis yields galactose. This polysaccharide may be identical with the immunopolysaccharide described by Goncalves and Yamaha (1959) (von Brand, 1962). Received for publication 16 April 1962. * This work was supported in part by a grant from the U. S. Public Health Service (E-1384) and funds from the International Atomic Energy Agency. t Present address: Dept. Tropical Medicine and Medical Parasitology, Louisiana State Univ. School of Medicine, 1542 Tulane Ave., New Orleans, Louisiana, USA. In view of the fact that utilization of galactose appears to set S. cruzi apart from other trypanosomes, and that galactose is involved in the synthesis of a major antigenic fraction of S. cruzi, further studies were initiated (in greater detail than those reported by Zeledon) on galactose utilization by culture forms of this