Irradiation polysaccharides

Significant protection of mice by several polysaccharides other than glucan isolated from S. cerevisiae has been described (209). A 2.16-fold protection in the LD q q is observed for one modifier, MNZ, when given 15 min prior to irradiation. Glucan protects 2.25-fold in this same protocol. Many of these polysaccharides may act through activation of the complement system, rather than directiy on ceHs. 

We have studied the effect of irradiation on both pectin and cellulose degradation extensively, both from the standpoint of the in vivo degradation as measured by the characteristics of the extracted polysaccharides 13, 16) and in model systems utilizing in vitro techniques 10, 12, 14, 26,... 

The result of irradiation clearly depends on the nature of the flour. The amylose component of starch suffers the least change. Overall changes in polysaccharide fraction are linear with the radiation dose.212-217-218... 

Percival E (1970) Algal polysaccharides. In Pigman W, Horton D (eds) The carbohydrates, vol IIB. Academic Press, New York, pp 541-544 Post AF, Dubinsky Z, Wyman K, Falkowski PG (1985) Physiological-responses of a marine planktonic diatom to transitions in growth irradiance. Mar Ecol Prog Ser 25 141-149... 

Interesting possibilities for the synthesis of new types of polysaccharide derivatives are offered by the reaction of addition to double bonds, which proceeds by a free-radical mechanism. The presence of initiators of free-radical polymerization (benzoyl peroxide, tert-butyl peroxide, dicumyl peroxide, dinitrile of azodiisobutyric acid), also irradiation with ultraviolet light, has effected the addition to 5,6-cellulosene of chloroform, carbon tetrachloride, methylmonochloroacetate, dimethyl-phosphite and other compounds that decompc under the conditions of a reaction with the formation of free radicals (45,46). The reaction proceeds as follows ... 

The irradiation of polysaccharides results predominately in their degradation. This explains why fruits and vegetables become soft on irradiation. This degradation is observed to occur both in solution and in the dry state. 

NMR is not only applicable to the solutions of the isolated polysaccharide, but also can be used for the study of human body fluids, e.g., the synovial fluids from patients suffering from RA [246] Subsequent to y-irradiation, increased peak intensities of the A-acetyl groups of HA (at about 2.04 ppm) could be clearly monitored [247]. Concomitantly, the intensity of another peak at 8.44 ppm increased. This resonance is stemming from formate and represents another important (low molecular) degradation product of HA in the synovial fluid. It is one of the major advantages of NMR that both high and low molar mass compounds can be simultaneously detected. Of course, NMR offers also the additional advantage that even completely unexpected metabolites can be monitored [248]. 

Different ways of enhancing the solubility of polysaccharides in ionic liquids have been reported. Recently, ultrasound irradiation has been used to increase enzyme activity in lipase-catalysed esterifications of glucose with vinyl laurate or lauric acid in ILs [67]. It was found that ultrasound irradiation significantly enhances the enzyme activity probably due to an increase in the dissolution and mass transfer rates of substrates, without any loss in enzyme stability. 

In these earlier studies, the polysaccharides were In open sample holders within the rf reactor. Thus, samples were exposed to fast moving high temperature electrons, the slower moving positive and negative ions, and free radicals as well as to uv irradiations. In all types of rf plasmas investigated, changes In surface properties of the polysaccharides were analyzed by the techniques of electron spectroscopy for chemical analyses (ESCA), electron spin resonance (ESR), multiple internal reflectance infrared spectroscopy (MIR) and chemiluminescence (CL). 

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