Solution properties and colloidal assemblies of various surfactants such as hydrocarbon types, fluorocarbon types, hybrid types are reviewed in terms of a single surfactant micelle formation and its solubilization, a mixed micelle formation and its solubilization, a microemulsion formation, an emulsion and emulsification, a vesicle formation, a liposome formation, a surfactant-free emulsion and etc.

View full abstract

Complex lipids are components of cell membranes and are thought to play important roles in a variety of biological phenomena, for example extracellular recognition, cell-cell interaction, differentiation, oncogenesis and immunity. We set out to perform a systematic structural survey of invertebrate sphingolipids, which may be classified according to their components as either phosphosphingolipids or glycosphingolipids, and are found in Protostomia phyla, Mollusca, Arthropoda, Annelida, Aschelminthes, Tentaculata, Coelenterata etc. These sphingolipids have been found to contain quite different con-stituents from those of Deuterostomia phyla, e.g. 2-aminoethylphosphonic acid, N-methylaminoethylphosphonic acid (C-P compounds) and phosphoethanolamine in phosphosphingolipids, and mannose, glucuronic acid, sugar phosphates (galactose-6-phosphocholine, glucosamine-6-phosphoethanolamine, glucosamine-6-phosphocholine, glucose-6-N-methylaminoethylphosphonic acid and inositol-1-phosphate) as well as methyl sugars etc. in glycosphingolipids. This review describes studies on the structural biochemistry of sphingolipids in invertebrates, including : 1, Structural studies on phosphosphingolipids; 2, Structural studies on glycosphingolipids; 3, Immunochemical studies on phospho- and glycosphingolipids; and 4, Preparation and analytical method of sphingolipids.

View full abstract

Biosurfactants (BS) produced by various microorganisms show unique properties (e.g. mild production conditions, lower toxicity, and environmental compatibility) compared to their chemical counterparts. The numerous advantages of BS have prompted applications not only in the food, cosmetic, and pharmaceutical industries but in energy and environmental technologies as well. A yeast strain of Candida antarctica was found to produce a large amount of mannosylerythritol lipids (MEL) from different vegetable oils or hydrocarbons. MEL exhibited not only excellent surface-active properties but also versatile biochemical actions, including antimicrobial activity and differentiation-inducing activity against human leukemia cells. Interestingly, MEL showed a remarkable anti-agglomeration effect on ice particles in an ice-water slurry system used for cold thermal storage, and attained a high ice-packing factor to improve the system efficiency and environmental load. MEL also displayed high binding affinity and capacity toward human imuunoglobulin G on polymer beads, indicating a great potential as a new affinity ligand for the protein. In addition, MEL showed excellent self-assembling properties to form giant liposomes. More significantly, the cationic liposomes bearing MEL increased dramatically the efficiency of gene transfection into mammalian cells. The yeast BS should thus be a new nano-biomaterial, and broaden their applications in various advanced technologies.

View full abstract