Identification of molecular species of ceramide amino-ethylphosphonate from oyster adductor by gas-liquid chromatography-mass spectrometry

MASS SPECTROMETRIC FRAGMENTATION OF TRIMETHYLSILYL AND RELATED ALKYLSILYL DERIVATIVES

This review describes the mass spectral fragmentation of trimethylsilyl (TMS) and related alkylsilyl derivatives used for preparing samples for analysis, mainly by combined gas chromatography and mass spectrometry (GC/MS). The review is divided into three sections. The first section is concerned with the TMS derivatives themselves and describes fragmentation of derivatized alcohols, thiols, amines, ketones, carboxylic acids and bifunctional compounds such as hydroxy- and amino-acids, halo acids and hydroxy ethers. More complex compounds such as glycerides, sphingolipids, carbohydrates, organic phosphates, phosphonates, steroids, vitamin D, cannabinoids, and prostaglandins are discussed next. The second section describes intermolecular reactions of siliconium ions such as the TMS cation and the third section discusses other alkylsilyl derivatives. Among these latter compounds are di- and trialkyl-silyl derivatives, various substituted-alkyldimethylsilyl derivatives such as the tert-butyldimethylsilyl ethers, cyclic silyl derivatives, alkoxysilyl derivatives, and 3-pyridylmethyldimethylsilyl esters used for double bond location in fatty acid spectra. © 2019 Wiley Periodicals, Inc. Mass Spec Rev 0000:1-107, 2019.

In vitro and in vivo anti-angiogenic activities and inhibition of hormone-dependent and -independent breast cancer cells by ceramide methylaminoethylphosphonate

Ceramide methylaminoethylphosphonate (CMAEPn) was isolated from eastern oyster ( Crassostrea virginica ) and screened against in vitro and in vivo angiogenesis and against MCF-7 and MDA-MB-435s breast cancer cell lines. In vitro angiogenesis was evaluated by the vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cell (HUVEC) tube formation assay. MCF-7 and MDA-MB-435s cell viability was evaluated by the CellTiter 96 AQ(ueous) One Solution Cell Proliferation assay. Apoptosis was evaluated by the caspase-9 assay, autophagy by acridine orange staining and beclin-1 level. Our study indicates that CMAEPn at 50 microM inhibited VEGF-induced tube formation by HUVEC. The viability of MCF-7 and MDA-MB-435s breast cancer cells exposed to 125 microM CMAEPn for 48 h was reduced to 76 and 85%, respectively. The viability of MCF-7 and MDA-MB-435s cells exposed to 250 microM CMAEPn for 48 h under the same conditions was reduced to 38 and 45%, respectively. CMAEPn at 125 microM inhibited VEGF-induced MDA-MB-435s cell migration and invasion. CMAEPn at 125 microM also decreased VEGF, EGF levels in the conditioned media, PI3K, IkappaB phosphorylation and degradation in the cytoplasmic extracts, and NFkappaB nuclear translocation. Both acridine orange staining and beclin-1 indicated autophagic cell death in MCF-7 and MDA-MB-435s cells, respectively. In vivo, CMAEPn at 30 mg/kg body weight inhibited bFGF-induced angiogenesis and caused a 57% reduction in hemoglobin levels in the matrigel plug assay within 7 days. This is the first report on CMAEPn-inhibited angiogenesis both in vitro and in vivo.

Sphingophosphonolipid molecular species from edible mollusks and a jellyfish

The goal of this study is to supplement the composition and nature of sphingophosphonolipids diversity from edible mollusks (Mytilus galloprovincialis, Eobania vermiculata) and from jellyfish Pelagia noctiluca, organisms rich in phosphonolipids. M. galloprovincialis contained a major ceramide 2-aminoethylphosphonate (CAEP-IM) and a minor ceramide that was detected chromatographically as the methyl analog (CAEP-IIM). In CAEP-IM, saturated fatty acids (FA) of 14, 16 and 18 carbons amounted to 68.8%; also 52.5% dihydroxy bases were detected. On thin layer chromatography, the Rf for CAEP-IIM was smaller than the Rf for CAEP-IM because of an increase of 22.0% in 2OH-16:0 FA, plus 29.2% trihydroxy bases (phytosphingosine). Similarly, a ceramide 2-methylaminoethylphosphonate (CAEP-IIE, 1.5% of phospholipids) was quantitated in Eobania (apart from the previously reported major CAEP, 7.6%). In CAEP-IIE, saturated and hydroxy FA of 14, 16 and 18 carbons amounted to 37.0 and 37.8%; 29.1% dihydroxy and 23.0% trihydroxy bases were detected in the same molecule. Eobania's unsaturated FA percentages (total lipids: 66.3, polar: 47.5, neutral: 59.0) were similar to those previously found for other land snails. A suite of two minor CAEP (CAEP-IIP, CAEP-IIIP) was quantitated in Pelagia at 2.0 and 1.3% of phospholipids (apart from the previously reported major CAEP, 21.0%) identified chromatographically as methyl analogs. In CAEP-IIP, saturated FA of 14, 16, 18 and 19 carbons amounted to 56.0%; 12.6% dihydroxy and 34.1% trihydroxy bases were also detected in CAEP-IIP. The Rf CAEP-IIIP<Rf CAEP-IIP owing to an increase of +8.5% of hydroxy FA and +12.3% of trihydroxy bases. The compositions of CAEP-IIM and CAEP-IIE appear to be specific of each organism, while the composition of molluscan or jellyfish major sphingophosphonolipids appears not specific.

Characterization of aminoalkylphosphonyl cerebrosides in muscle tissue of Turbo cornutus

From muscle tissues of the marine snail (Turbo cornutus) aminoalkylphosphonyl cerebrosides, which had been shown to be present in visceral parts were isolated. Their structure was determined by degradative methods and by characterization of components by gas chromatography-mass spectrometry. The aminoalkylphosphonyl cerebroside fraction consisted of a major portion of 1-O-[6'-O-(N-methylaminoethylphosphonyl) galactosyl] ceramide and a minor portion of a novel lipid, 1-O-[6'-O-(aminoethylphosphonyl)galactosyl] ceramide. The fatty acids of the fraction were mainly palmitic (53.3%) and 2-hydroxy palmitic acid (14.6%). The long chain bases were mainly dihydroxy C22: 2(36.6%), C18:1 (14.6%) and trihydroxy bases were also found as minor components.

Phosphonosphingoglycolipid, a novel sphingolipid from the viscera of Turbo cornutus

A novel lipid which contained long-chain base, fatty acid, galactose and N-methylamino-ethylphosphonic acid in an equimolar was isolated from the viscera of Turbo cornutus. The method used for the structural elucidation of this lipid were partial acid hydrolysis, alkaline hydrolysis, periodate oxidation and Smith degradation. The structure of break-down products were mainly identified by combined gas chromatography and mass spectrometry. The structure of the novel lipid was determined to be 1-O-[6'-O-(N-methylaminoethyl-phosphonyl) galactopyranosyl] ceramide. Mass spectra of galactose-N-methylaminoethylphospnate and glycerol-N-methylamino-ethylphosphonate are given.

Branched long-chain bases from the bivalve Corbicula sandai

Long-chain bases were liberated from a crude mixture of sphingolipids from whole tissue of the fresh-water bivalve C. sandai, and conversion of the bases into N-acetyl-0-trimethylsily derivatives was accomplished. The derivatized bases were analyzed by combined gas-liquid chromatography and mass spectrometry. A portion of the sphingolipids was subjected to catalytic hydrogenation from whch saturated long-chain bases (sphinganines) were obtained. The saturated bases were oxidized with lead tetra-acetate and the aldehydes produced were analyzed by gas-liquid chromatography. The aldehydes were further oxidized to acids with silver oxide, the resulting fatty acids methylated and also analyzed by gas-liquid chromatography. By these analyses, altogether five long-chain bases were identified, consisting of hexadeca-4-sphingenine (15%), heptadeca-4-sphingenine (2%), iso-octadeca-4-sphingenine (13%), octadeca-4-sphingenine (39%) and anteiso-noadeca-4-sphingenine (31%). So far no branches have been found in shellfish spingolipid long-chain bases.