Although the yeast Saccharomyces cerevisiae has only one sphingolipid class with a head group based on phosphoinositol, the yeast Pichia pastoris as well as many other fungi have a second class, glucosylceramide, which has a glucose head group. These two sphingolipid classes are in addition distinguished by a characteristic structure of their ceramide backbones. Here, we investigate the mechani...

A single-step pathway for the synthesis of the compatible solute glucosylglycerate (GG) is proposed based on the activity of a recombinant glucosylglycerate synthase (Ggs) from Persephonella marina. The corresponding gene encoded a putative glycosyltransferase that was part of an operon-like structure which also contained the genes for glucosyl-3-phosphoglycerate synthase (GpgS) and glucosyl-3-...

PURPOSE The precise mechanisms involved in photoreceptor apoptosis are still unclear. In the present study, the role of ceramide, a sphingolipid precursor that induces apoptosis on cellular stress, was investigated in relation to the activation of cell death in photoreceptors. METHODS Rat retina neuronal cultures, with or without docosahexaenoic acid (DHA), were treated with the ceramide anal...

Sphingomyelin synthase-related protein (SMSr) synthesizes the sphingomyelin analog ceramide phosphoethanolamine (CPE) in cells. Previous cell studies indicated that SMSr is involved in ceramide homeostasis and is crucial for cell function. To further examine SMSr function in vivo, we generated Smsr KO mice that were fertile and had no obvious phenotypic alterations. Quantitative MS analyses of ...

Galactosyl ceramide is made in mouse brain from ceramide and uridine diphospho galactose (UDPGal)16,1L The enzyme system, evaluated in vitro, shows a marked preference for 2-hydroxy fatty acids (HFA) ceramide when compared with nonhydroxy fatty acids (NFA) ceramide, although brain contains HFA and NFA cerebroside in similar amounts. We do not yet know whether this difference is due to enzyme sp...

Gangliosides were extracted from purified human and porcine thyrotropin (TSH) receptors (TSH-R) and were detected by probing with an 125I-labeled sialic acid-specific lectin, Limax flavus agglutinin. Gangliosides copurified with human and porcine TSH-R migrated between monosialoganglioside GM1 and disialoganglioside GD1a. Ceramide glycanase digestion of the purified human TSH-R-associated glyco...

We investigated the possibility of the proapoptotic lipid ceramide as an indicator of chemoresistance in leukemia. Doxorubicin (DOX) increased the ceramide level and apoptosis in drug-sensitive HL-60 cells but not in drug-resistant HL-60/ADR cells, under the condition that the uptake of DOX was not different between the two cell lines. In addition, exogenous N-acetylsphingosine (C2-ceramide) en...

Bovine lactoferricin (LfcinB) is a cationic peptide that selectively induces caspase-dependent apoptosis in human leukemia and carcinoma cell lines. Ceramide is a second messenger in apoptosis signaling that has been shown to increase the cytotoxicity of various anti-cancer drugs. In this study, we determined whether manipulation of intracellular ceramide levels enhanced LfcinB-induced apoptosi...

Sphingoid bases are growth inhibitory and pro-apoptotic for many types of cells when added to cells exogenously, and can be elevated to toxic amounts endogenously when cells are exposed to inhibitors of ceramide synthase. An important category of naturally occurring inhibitors are the fumonisins, which inhibit ceramide synthase through structural similarities with both the sphingoid base and fa...

Although mechanisms involved in the pathogenesis of asthma remain unclear, roles for oxidative/nitrosative stress, epithelial cell apoptosis, and airway inflammation have been documented. Ceramide is a sphingolipid with potent proinflammatory and proapoptotic properties. This study aimed at determining whether increased formation of ceramide contributes to the development of airway inflammation...