Sorbitol cycle

A new class of sesterterpenes in which the middle three units of a penta-isoprenoid chain cyclised into a bicyclic system, leaving the first and the last isoprenoids to substitute the decaline moiety, was isolated from sponges of genus Dysidea and Ircinia. From the Palauan Dysidea sp. was isolated dysideapalaunic acid (107) that inhibited the aldose reductase [124]. An inhibitor of aldose reductase is expected to prevent neuropathy or cataract as a complication of diabetes. These diseases are caused by the accumulation of sorbitol in the peripheral nerve or the crystalline lens, as a result of enzymatic reduction of glucose by the aldose reductase in the sorbitol cycle [125,126]. The absolute stereochemistry of dysideapalaunic acid was established by its total synthesis [127,128],... 

A number of studies on the metabolism of 3FG and 4FG in Locusta miaratoria have been undertaken. Both 3FG and 4FG are toxic to locust with LD50 s of 4.8 mg/g and 0.6 mg/g respectively. In vitro studies showed that 3FG is metabolized in the fat body, via the NADP-linked aldose reductase, to 3-deoxy-3-fluoro-D-glucitol (3FGL). This metabolite was detected in the hemolymph of the insect and shown to be both a competitive inhibitor and a substrate for NAD-linked sorbitol dehydrogenase, thereby generating 3-deoxy-3-fluoro-D-fructose (3FF) (541. Subsequently, it was shown by in vivo radio-respirometric analysis of C02 and appropriate chase experiments, that 3FG metabolism irreversibly inhibits glycolysis and not the hexose monophosphate shunt or tricarboxylic acid cycle (55). In addition, the release of fluoride ion and H20 from D-[3- H]-3FG was also observed. Based on the mechanism of aldolase (55) and triosephosphate isomerase... 

A variety of carbohydrate sources such as arabinose, fructose, galactose, mannitol, mannose, ribose, sorbitol and xylose are utilised by AAB through the hexose monophosphate pathway (De Lay et al., 1984), Embden-Meyerhof-Pamas (EMP) and Entner Doudoroff (ED) pathway (Attwood, van Dijken, Pronk, 1991). Acetobacter can also oxidise various organic acids into CO2 and H2O through the tricarboxylic acid (TCA) cycle, but like Glucombacter lacks a functional TCA cycle, which limits oxidation of organic acids (Seo et al., 2004). 

Crompton s carboxylic acid based nucleating agent, Moldpro 931 is said to cost only a third as much as benzylidene sorbitol varieties or the organophosphate salts, and is also claimed to have exceptionally low effects on odour and taste. Moldpro 931 is designed to reduce the cycle time in making polypropylene water bottles. Its action depends on the presence of a small quantity of residual aluminium catalyst, and it does not work if the antistatic additive, glycerol monostearate, is present. 

Aluminum hydroxybis 2,2 -methylenebis[4,6-di(teit-butyl)phenyl]phosphate was used to manufacture the bi-oriented polypropylene bottle, designed to replace PET bottles. The new bottles are cheaper to produce and do not require use of soibitols for clarification (sorbitols increase process temperature and impact cycle time). ... 

An influence of carbon sources on the growth of P. sizovae and biosynthesis of agroclavine-I and epoxyagroclavine-I, as well as the activity of key enzymes of the Krebs cycle, the pentose phosphate pathway and glyoxalate cycle were studied (Kozlovsky and Vepritskaya, 1987). The best alkaloid productivity was observed with mannitol and fumaric acid as the carbon sources. A combination of sorbitol with fumaric acid stimulated epoxyagroclavine-I synthesis. A high alkaloid production was accompanied by high activity of the pentose phosphate cycle and low activity of the Krebs cycle. 

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