| Abstract: | The 31P nuclear magnetic resonance (NMR) spectrum of the digestive gland-gonad complex (DGG) of the schistosome vector Biomphalaria glabrata was characterized and the effects of infection by Schistosoma mansoni noted. The in vivo spectrum was comprised of 11 peaks, 5 downfield and 6 upfield of an external 85% phosphoric acid standard. Based on a variety of analytical procedures, the upfield peaks from the standard were demonstrated to be composed of carbamoyl phosphate + a mixture of 3 phosphatides and sphingomyelin, the gamma + beta phosphorus resonances of nucleotide triphosphate (NTP) and nucleotide diphosphate (NDP), respectively, the alpha phosphorus resonances of NTP + NDP, NAD(H) + the phosphorus resonance of uridine phosphate from uridine diphosphoglucose (UDPG), the phosphorus resonance of glucose phosphate from UDPG and, last, the beta phosphorus resonance of NTP. The downfield peaks were assigned as glycerophosphoryl choline, intracellular inorganic phosphate (Pi), sugar phosphates + phosphoryl choline, aminoethyl phosphonate (AEP), and ceramide AEP. T1 values for the in vivo NMR components were determined by inversion recovery. Infection produced distinct alterations in the levels of nonnucleotide components of the in vivo 31P NMR spectrum and the spectra of tissue extracts. Specifically, the levels of phosphonate, phospholipids, and carbamoyl phosphate were markedly reduced, and the relative level of Pi was increased. The potential significance of these changes to the parasite-host relationship was discussed. In contrast, starvation resulted in a decreased level of phosphonate only. The pH of the intact DGG was estimated by titrating the inorganic phosphate component of tissue extracts. The mean pH was 6.9 for both control and infected material. |
