Structural studies on the neutral glycosphingolipids of Manduca sexta

Abstract

Glycosphingolipids (GSLs) have been implicated as playing major roles in cellular interactions and control of cell proliferation in muticellular organisms. Moreover GSLs and other sphingolipids such as sphingomyelins, ceramides and sphingosines serve a variety of roles in signal transduction. Hence, identification of structures of GSLs in different biota will shed light in understanding their physiological role. During this study, the major glycosphingolipid component present in the extracts of stage-12 and stage-17/18 metamorphosing adults of Manduca sexta was identified as mactosyl ceramide. We report the isolation of several ceramide disaccharides, a ceramide trisaccharide and a ceramide tetrasaccharide. The GSL structures were confirmed by high-resolution mass spectrometry and tandem mass spectrometry. The identity of the monosaccharides was proved using exoglycosidases. The predominant sphingosine chain-length varied from C-14 (tetradecasphing-4-enine) to C-16 (hexadecasphing-4-enine) in these GSLs. Sphingosines of both chain lengths were accompanied by their doubly unsaturated counterparts tetradecasphinga-4,6-diene and hexadecasphinga-4,6-diene. It is also interesting to note the presence of tetradecasphinganine and hexadecasphinganine in minute amounts in the form of a GSL in the extracts of M. sexta. The varying degrees of unsaturation in the sphingosine moiety of GSLs in M. sexta may be biologically significant in insect metamorphosis. The ceramide trisaccharides and ceramide tetrasaccharide belong to the arthro-series, The observation of fucose in the M. sexta GSLs is the first report of the presence of fucose in an arthroseries GSL.

Biochemical studies on sphingolipids of Artemia franciscana: novel neutral glycosphingolipids

“…In the structures of nAtCTeS and CHS, " ␣ -anomeric" GlcNAc was attached at the nonreducing end. This type of sugar chain in GSL structure is reported in only a few cases: GlcNAc ␣ 4Gal ␣ Cer from the marine sponge Axinella damicornis ( 29 ), GlcNAc ␣ 1-HPO 3 -the fruit fl y Drosophila melanogaster ( 33 ), the insect culture cell line High Five Cell derived from the cabbage looper Trichoplusia ni ( 31 ), the moth Manduca sexta ( 34 ), and the millipede Parafontaria laminata armigera ( 28 ), all of which have been verifi ed to contain At 3 Cer. From the brine shrimp, arthro-series GSL (At 3 Cer) was characterized as a minor CTS, but on the other hand, and surprisingly, a nonarthro-series GSL (nAtCTS) was characterized as a major CTS.…”

Structural elucidation of two types of novel glycosphingolipids in three strains of Skeletonema by liquid chromatography coupled with mass spectrometry

“…These amphipathic glycosphingolipids have been isolated from diverse natural sources, including plants, insects, marine sources, microorganisms, and humans . Several analytical methods have been used to characterize glycosphingolipids from biological samples .…”

“…Thin‐layer chromatography (TLC), high‐performance liquid chromatography (HPLC), gas chromatography (GC), and gas chromatography/mass spectrometry (GC/MS) have been used to identify the structures of the long‐chain sphingoids and fatty acids in sphingolipid molecules by complicated derivatization or alkaline hydrolysis . The use of enzyme reagents has become popular in modern carbohydrate analysis because of their inherent selectivity for a saccharide substrate and its linkage type . However, the structure of a saccharide could not be determined from a mixed sample by enzymatic assays.…”

Structures and functions of invertebrate glycosylation

“…GSLs are structurally diverse mainly due to variable sugar modifications to the ceramide, and the glycan moiety of invertebrate GSLs differs notably from those of vertebrates. Vertebrates have a GSL core disaccharide Gal(β1–4)Glcβ linked to the ceramide, whereas for invertebrates the most common core disaccharide is Man(β1–4)Glc [81–83], except for the mollusc Aplysia kurodai , whose GSL core is the same as in vertebrates [84]. In addition, the ceramide moiety of invertebrate GSLs is found to be different from those of vertebrates, in that the sphingosine chain is shorter for invertebrates [81].…”

“…Recently, GSLs of the lepidopteran species B. mori were investigated, which contain the same conserved core structure, but novel extensions were revealed (figure 3) [87]. The major GSL components for Manduca sexta were identified as mactosyl ceramide [81]. Gangliosides, GSLs modified with sialic acid residues, have not been reported for invertebrates to date.…”