van Oordt B E, Tielens A G, van den Bergh S G
Laboratory of Veterinary Biochemistry, State University of Utrecht, The Netherlands.
Parasitol Res. 1988;75(1):31-5. doi: 10.1007/BF00931187.
A detailed study was made of the changes in the carbohydrate metabolism of Schistosoma mansoni occurring during both the penetration of the skin of a hamster and the subsequent development of the schistosome in the lung, liver, and mesenteric veins of the host. During infection, within a few hours a transition occurs from a fully aerobic to a largely anaerobic energy metabolism. By 5 h postinfection, about 6% of carbohydrate breakdown occurs in the aerobic reactions of the Krebs cycle, whereas the rest occurs in the anaerobic formation of lactate. The contribution of aerobic processes to carbohydrate breakdown remains at this level of 6% until 3 weeks postinfection and then gradually declines to the adult level of 2.5%. Measurement of the protein content of developing schistosomes shows that an exponential growth occurs over a 15-day period after the arrival of the schistosomes in the liver (days 11-25 postinfection). During this period the protein content of the parasites increases about 100-fold, but despite this change in size, no major changes occur in the end-product pattern of carbohydrate breakdown. We conclude that during this period the rate of oxygen diffusion into the tissues is not a limiting factor for aerobic metabolism. A limited diffusion of oxygen may play a role in the decreasing contribution of aerobic processes during the later stages of maturation of the schistosomes.
对曼氏血吸虫在穿透仓鼠皮肤以及随后在宿主体内的肺、肝和肠系膜静脉中发育过程中碳水化合物代谢的变化进行了详细研究。在感染过程中，几小时内就会从完全有氧的能量代谢转变为主要厌氧的能量代谢。感染后5小时，约6%的碳水化合物分解发生在三羧酸循环的有氧反应中，其余则发生在乳酸的厌氧形成过程中。有氧过程对碳水化合物分解的贡献在感染后3周内一直保持在6%的水平，然后逐渐下降至成虫阶段的2.5%。对发育中的血吸虫蛋白质含量的测量表明，血吸虫到达肝脏后（感染后第11 - 25天）的15天内呈指数增长。在此期间，寄生虫的蛋白质含量增加约100倍，但尽管大小发生了这种变化，碳水化合物分解的终产物模式并未发生重大变化。我们得出结论，在此期间，氧气向组织中的扩散速率不是有氧代谢的限制因素。有限的氧气扩散可能在血吸虫成熟后期有氧过程贡献减少中起作用。
