Chemistry Reference
In-Depth Information
sleeping sickness: African trypanosomiasis
Disease caused by the protozoal parasite
Trypanosoma brucei
and transmitted by
tsetse fl ies. Approximately 10
7
molecules of the variable surface glycoprotein
(VSG), which is inserted into the plasma membrane via a GPI anchor, shield the
parasite from the immune system.
solvation
Association of solvent molecules with the solute molecules or ions. Solvation
energy can be approximated by calculation of energy contributions, corresponding
to cavity, dispersion, electrostatic and specifi c interaction terms between the solute
(carbohydrate) and solvent (water) molecules.
sphingoid
Class of long -chain aliphatic amines, containing two or three hydroxyl groups.
Sphingoids are a primary part of sphingolipids.
sphingolipid
A lipid containing sphingosine as component within the hydrophobic part of an
amphipathic structure. In most cases, this unit is ceramide, which usually has a
polar moiety (e.g., an oligosaccharide chain or phosphocholine) attached to the
fi rst (primary) hydroxyl of sphingosine. Sphingomyelin and gangliosides are char-
acteristic sphingolipids, the latter a glycosphingolipid.
sphingosine
An 18 - carbon amino alcohol (2 - amino - 4 - octadecene - 1,3 - diol). The most abundant
sphingoid in animal tissues.
stem cell
Cell with self-renewing capabilities that can differentiate into multiple cell
lineages.
stereoselectivity
The preferential formation of one stereoisomer over another in a chemical
reaction. When the stereoisomers are enantiomers, the phenomenon is
called enantioselectivity; when they are diastereoisomers, it is called
diastereoselectivity.
sub - telomeric
Occupying a location just below the end of a chromosome. The telomere structure
located at a chromosome's end plays important roles in its stability and resistance
to ageing.
sugar
A term used almost synonymously to carbohydrate.
