Comparisons of glucose and amino acid use in adults and microfilariae of Brugia pahangi.

With [U-14C]glucose we confirmed that essentially all of the glucose carbon used aerobically by intact Brugia pahangi adults was accounted for in the recovered lactate, in spite of the presence of cristate mitochondria in these parasites. Approximately 0.2% of the glucose carbon that disappeared was recovered in CO2. However, aerobiosis was required for the incorporation of alanine, proline, and glutamate into both respiratory CO2 and protein, but the glucose was used on the order of 1000 times faster than the amino acids. Homogenate fractions were examined for amino acid use, and all except the 100,000 g soluble fraction showed activity. However, all of the active fractions also contained living microfilariae and other developmental stages that arise from the adult uterus, since the females give birth to living larvae. Sonicates of the microfilariae formed CO2 from proline 30 times more rapidly than crude homogenates of the adult. Similarly, CO2 was formed from glucose 14 times more rapidly by intact microfilariae than by intact adults. The possibility arises that the low rates of CO2 formation from both the amino acids and glucose by intact adults may arise from the metabolism of the aerobic microfilariae and other developmental stages present in utero.