Lipid similarities

Extraction of lipid from small amounts (<1 g) of sample, such as that of rotifers, artemia, and larvae, may be achieved using an alternate procedure. In this approach, homogenization of sample is achieved using a vortex due to the delicate nature of tissues involved and the ease of their disintegration. The recovered lipids, similar to that in the original protocol (see Basic Protocol 2), may be used for further analysis. 

Unlike DOGSDSO, the present series harbor disulfide bonds in every important position of the cationic lipid. Similarly to RPR120535, these cationic hpids are not formulated with DOPE or other co-lipid(s) for optimal transfection efficiency. Based on exhaustive structure-activity relationship studies, we concluded that RPR-132688 is ten times more active than RPR120535. 

Absorption of the quaternary carbamates from the conjunctiva, skin, and lungs is predictably poor, since their permanent charge renders them relatively insoluble in lipids. Similarly, much larger doses are required for oral administration than for parenteral injection. Distribution into the central nervous system is negligible. Physostigmine, in contrast, is well absorbed from all sites and can be used topically in the eye (Table 7-4). It is distributed into the central nervous system and is more toxic than the more polar quaternary carbamates. The carbamates are relatively stable in aqueous solution but can be metabolized by nonspecific esterases in the body as well as by cholinesterase. However, the duration of their effect is determined chiefly by the stability of the inhibitor-enzyme complex (see Mechanism of Action, below), not by metabolism or excretion. 

The fact that Sulfolobus and Thermoplasma have similar lipids is of interest, but almost certainly this can be explained by convergent evolution. This hypothesis is strengthened by the fact that Halobacterium, another quite different organism, also has lipids similar to those of the two acidophilic thermophiles. [14]... 

Plant lipids increase the nutritional value of food they contain more essential FA than animal fats. They also contain tocopherols and tocotrienols, which are the most important sources of vitamin E. A disadvantage is that plant lipids (similar to animal fats) considerably increase the content of available energy. Therefore, the consumption of fried foods should be restricted because they are rich in fat. 

Ion bridging between biopolymers by and Mg ions seems to be the primary driving mechanism. The aggregates are composed of carbohydrates, proteins, and lipids, similar to the colloidal concentrates of Wells and Goldberg... 

Sulphate groups in sugars are of two kinds, sulphate esters and sulph-amido-groups. The former are simply called sulphates, with the position of the ester indicated by the number of the carbon atom to which it is attached. Galactose -3-sulphate, for example, is common in sulphated galactosphingo-lipids. (Similar rules apply with phosphate ester groups.)... 

When Ca (or UO ) was present in the subphase (Fig. 3), a mixed monolayer of GMO with dpPE also showed negative deviations in the molecular area and surface potential and behaved, at high pressures, like a mixed monolayer with dpPC. Such experiments indicated that dpPE can show interactions with fusogenic lipids similar to dpPC, depending on the surface pressure of the film and on the degree to which the dipolar properties are constrained by the influence of an external bivalent metal ion (Maggio Lucy, 1976). 

From elemental analysis, IR and C-NMR spectroscopy and GC-MS investigations of pyrolysates, PRB B isolated from the B race ca 10% of dry biomass), exhibits very similar structural features when compared to PRB A only slightly more important methyl-branching is observed in the former (77). In addition, feeding experiments with radio-labelled compounds confirmed the involvement of long unbranched, hydrocarbon chains in the biopolymer network. Indeed, sodium DL [2- " C] mevalonate, a botryococcene precursor, was poorly incorporated, while [lO- C] oleic acid resulted in strongly labelled PRB B (69, 72) in this latter case radioactivity was recovered both in the hydrocarbons and the fatty acids released on pyrolysis. To date the origin of PRB B is still obscure, no ether lipids similar to those found in the A race have been so far isolated from the B race. 

In this chapter, studies involving surfactants are somewhat arbitrarily separated from those that concern lipids. Similarities or differences of behavior are pointed out whenever necessary. The chapter is organized as follows. Section II reviews the dynamics of the surfactant Lg phase and of transitions between various lyotropic phases. Section III deals with the dynamics of phase transitions in lipid/water mixtures. Section IV reviews the dynamics of phase transitions induced by shear. Section V concludes this chapter. 

There is interest in the use of biopolymers to replace plastics in packaging for reasons of biodegradability and that these are renewable resources [112]. Thermoplastic properties of wheat gluten have been studied by the application of DMA and DSC to gluten films. Strong, transparent and water-resistant films can be obtained by casting films from ethanol/acetic, acid/water solvents. Moreover, the water-vapour barrier properties could be improved by the incorporation of lipids. Similarly, the manipulation of the different fractions of gluten could also produce distinct characteristics. 

Grell, E., Lewitzki, E., von Raumer, M., Hormann, A. Lipid-similar thermal transition of polyethylene glycol alkyl ether detergents. J. Therm. Aned. Galorim-etry 1999, 57(1), 371-375. 

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