Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 26, 2000
Publication Date: N/A
Technical Abstract: The structural elucidation of monoglycosylceramides (MGCs) from nematodes via spectroscopic and other methodologies is reviewed. In mixed stages of Caenorhabditis elegans, glucose was the only sugar moiety detected in the MGCs; the only sphingoid base was an unusual iso-branched, 17-carbon compound with a C-4 double bond. The fatty acids consisted primarily of straight-chain, saturated, 2-hydroxylated C-20 to C-26 acids; some iso-branched analogs also occurred. Analysis of similar material from eggs of Meloidogyne incognita revealed a similar material comprising 0.17% of the dry weight of nematode eggs. Although the sphingoid base and sugar compositions of the substances from C. elegans and M. incognita were identical, the fatty acids of the M. incognita MGCs were largely unsaturated, with nearly two-thirds being a hydroxylated 24-carbon monounsaturated acid (2-hydroxy-n-tetracosenoic acid). Ozonolysis indicated that the double bond was at the omega-7 position, a common position for double bonds in root-knot nematode glyceride fatty acids. Ability of C. elegans and M. incognita to biosynthesize monoglycosylceramides was indicated by analysis of sterile culture medium for C. elegans and roots of the host plant for M. incognita. In another comparative experiment, MGCs were not detected in cysts of Heterodera glycines; the threshold of detection was 0.005% of nematode dry weight.