Comparative analyses of brain ganglioside composition from cold-blooded vertebrate species living in different climates, and from mammals during ontogenetical or seasonal changes in their body temperature, support the idea that gangliosides are involved in thermal adaptation of neuronal membranes. The changes in ganglioside patterns evoked by experimentally induced cold acclimation of fish confirm the rule “the lower the environmental temperature the more polar is the composition of brain gangliosides”. Evidence from artificial mono-and bilayer membrane model systems reveals the thermo-sensitivity of the surface behavior of gangliosides and of ganglioside-calcium interactions. Very recent data demonstrate that gangliosides evoke drastic changes in the temperature-dependent kinetics of a peptide channel incorporated into a bilayer, suggesting that gangliosides are able to modulate basic membrane properties. The implications of these findings in vivo and in vitro are discussed in the search for a general physicochemical model of ganglioside function in neuronal membranes.
Parasitic protozoans including the members of trypanosomatidae family are the cause of diseases in humans and livestock. A majority of the glycoproteins present on plasma membrane of these parasites are attached by glycosyl-phosphatidylinositol (GPI)-anchor. In addition, plasma membrane of some of the protozoans is decorated with free GPIs which are not attached to proteins. The structure and biosynthesis of GPIs in protozoans as compared to higher eukaryotes and their utility as targets for anti-protozoan chemotherapy is discussed. The crucial role of GPIs and GPI-attached glycoproteins in protozoan parasites infectivity and survival is the focus of this review.
Glycosphingolipids are amphiphilic components of cellular plasma membranes. Their constitutive degradation occurs in the acidic compartments of the cells, the endosomes and the lysosomes. It is an open question how the lysosomal degradation of membrane lipids is achieved without the destruction of the lysosomal membrane itself, which is entirely composed of substrates of the hydrolytic enzymes present in the lysosol. Several lines of evidence point to intralysosomal vesicles as the real substrate of the lysosomal degradation machinery. Presumably, they differ from the lysosomal membrane in terms of lipid composition, curvature, lateral pressure, and the absence of a glycocalix blocking the access of the hydrolytic enzymes and activator proteins. This review summarizes principles and recent findings of glycolipid enzymology which shed light on this poorly understood phenomenon. On the other hand, the in vitro investigation of the multicomponent system responsible for glycolipid degradation in the lysosome has to take into account topological features present in the lysosomes of the cell.
This is a brief guide to the Glycoscience Network (TGN), an informal world-wide grouping which shares information related to carbohydrates. At the present time, we can easily obtain a lot of information on the World Wide Web (WWW) pages. But there may be a lot of people that wish to know which site is useful for carbohydrate studies. Furthermore, some people may use older computers on which WWW browsers such as Netscape and Internet Explorer can not work. It will be helpful for them to be aware of the mailing list of the glycoscience Network (TGN mailing list). Anyone who can receive and send e-mail is able to obtain lots of information from glycoscientists anywhere in the world through the TGN mailing list. Iain Wilson and Barry Hardy, who set up TGN, explain the history and the purpose of TGN in a paper titled “Glycoscience and the Internet” which was published in TIGG (1996), 8: 301-310. In this paper, we will describe for beginners how to use the TGN mailing list.