Butanol Partition Research Articles

Synthesis and characterization of hydroquinone glucoside using Leuconostoc mesenteroides dextransucrase

We synthesized a hydroquinone glucoside (HG) as a potential skin-whitening agent using Leuconostoc mesenteroides (B-1299CB BF563) dextransucrase with hydroquinone (HQ) as an acceptor and sucrose as a donor. The product was purified using butanol partitioning and silica gel column chromatography. The structure of the purified HG was determined by nuclear magnetic resonance and the ionic product was observed at m/ z 295 (C12, H16, O7 Na) +. HG was identified as 4-hydroxyphenyl-α- d-glucopyranoside. The optimum condition of HG synthesis, determined using a response surface methodology, was 450 mM HQ, 215 mM sucrose, and 0.55 U/mL dextransucrase; the final HG produced was 544 mg/L. The IC 50 of diphenylpicryl-hydrazyl scavenging activity was 3.85 mM indicating a higher antioxidant activity compared to β-arbutin (IC 50 = 6.04 mM). HG-mediated inhibition of lipid peroxidation was 3.51% that of HQ (100%) and much higher than that of β-arbutin (0.81% of HQ). In addition the IC 50 value of nitrite-scavenging activity was 14.76 mM showing a superior scavenging activity to that of β-arbutin (IC 50 = 27.09 mM).

Experimental analysis of a product inhibited fermentation in an aqueous two-phased system

Two aqueous two-phased sytems were investigated to determine their ability to reduce product inhibition in the acetone-butanol-ethanol (A-B-E) fermentation. In an attempt to avoid the high cost of fractionated dextran, an industrial-grade dextran (DEX) and a hydroxylpropyl starch polymer, whose commercial name is Aquaphase PPT (APPT), were tested as the copolymer with polyethylene glycol (PEG) to form the two-phased fermentation broth. The two-phased fermentation performances in the DEX-PEG and APPT-PEG two-phase systems were compared to a single-phased conventional fermentation through a series of batch runs. Also, the effects of the phase forming polymers on Clostridium acetobutylicum were investigated. With the butanol partition coefficient of 1.3, which is defined as the concentration ratio of butanol in the continuous and dispersed phases, the butanol yield with the two-phased system was increased by 27% in comparison to the conventional fermentation.

Assembly and deacetylation of N-acetylglucosaminyl-plasmanylinositol in normal and affected paroxysmal nocturnal hemoglobinuria cells.

Decay-accelerating factor (DAF) is anchored in cell membranes by a glycosyl-plasmanylinositol (GPI) moiety that is transferred to it en bloc in the rough endoplasmic reticulum. To analyze the biochemical reactions involved in preassembly of this structure, a human hematopoietic cell-free system was employed. Incubation of cell extracts with UDP-[3H]GlcNAc and butanol partitioning of reaction mixtures yielded two products similar in TLC mobility to intermediates described in Trypanosoma brucei. Both species were sensitive to Bacillus thuringiensis phosphatidylinositol-specific phospholipase C, indicative of association of [3H]GlcNAc label with a plasmanylinositol-containing acceptor. In contrast to trypanosome intermediates, which contain phosphatidylinositol (1,2-diacylglycerophosphoinositol), however, alkali treatment and phospholipase A2 digestion generated butanol-phase products characteristic of glycosylated plasmanylinositol (1-alkyl-2-acylglycerophosphoinositol). Kinetic and pulse-chase experiments indicated that the slower-migrating species was a product of the faster and that it, but not the faster, was sensitive to both GPI-specific phospholipase D and nitrous acid deamination, consistent with conversion of GlcNAc- to GlcN-plasmanylinositol. Accordingly, acetic anhydride acetylation retransformed the slower species back to the faster. Further incubation with cell extracts converted the slower species into more polar products. Lysates of normal and of affected blood leukocytes from two paroxysmal nocturnal hemoglobinuria (PNH) patients supported assembly of the two intermediates within 1 min. Thus, the initial enzymes mediating human GPI-anchor assembly are GlcNAc-plasmanylinositol transferase and GlcNAc-plasmanylinositol deacetylase, their substrates contain plasmanylinositols, and the products of their activities are normal in affected PNH cells.

Effect of Light and Ethylene upon Cytokinin Levels in Seed ofSpergula arvensis

The breaking of dormancy in Spergula arvensis L. seed by light and ethylene is accompanied by severalfold increases in the levels of endogenous cytokinins prior to germination, the largest rise being observed in the cytokinin-ribotide fraction. Pretreatment of seed with cytokinins does not, however, substitute for the light or ethylene requirements. INTRODUCTION It has been shown (Olatoye and Hall, 1972) that germination of Spergula arvensis L. seed is promoted by treatment with ethylene and that the process is phytochrome controlled. The evidence suggests that ethylene removes an inhibition to the expres sion of the light response. Recent work by van Staden, Webb, and Wareing (1972) has shown that in seeds of Acer saccharum stratification results in substantial increases in cytokinin activity prior to germination; likewise it was shown that in seed of Rumex obtusifolius cytokinin levels increase rapidly in response to red light treatment, the effect being reversible by far-red illumination (van Staden and Wareing, 1972). These workers suggest that cytokinin production in such seeds is phytochrome controlled. The purpose of the work described here was to determine whether a similar rise in cytokinin levels in S. arvensis seed occurs under inductive conditions prior to germination and if this occurs whether it could account for the breaking of dormancy by ethylene and light. METHODS For cytokinin extraction 5-g lots of S. arvensis seed were incubated at 20 °C for 48 h on moist filter-paper in 350 ml McCartney bottles, fitted with serum caps in their lids for ethylene injection. Experiments were carried out both in the dark and in continuous white light in the presence or absence of 200 /xl/1 ethylene. The material was extracted as previously described (van Staden et al., 1972), except that the extracts were not partitioned against petroleum ether. The aqueous fraction from the last butanol partition was treated with alkaline phosphatase to convert ribotides to ribosides. All fractions were taken to dryness, redissolved in 35 per cent ethanol, streaked on Whatman No. 3MM chromatography paper, and separated with water saturated sec-butanol. The chromatograms were divided into 10 equal strips and assayed for cytokinin activity with the soybean callus bioassay. No activity could be detected in the ethyl 1 Present address : Botany Department, University of Natal, Pietermaritzberg, South Africa. 2 Present address: Department of Forest Research, P.M.B. 5054, Ibadan, Nigeria. This content downloaded from 207.46.13.111 on Tue, 09 Aug 2016 06:10:13 UTC All use subject to http://about.jstor.org/terms Effect of Light and Ethylene on Cytokinin Levels 663 acetate fraction. Germination tests were carried out in 30-ml McCartney bottles lined with a double layer of Whatman No. 1 filter-paper discs moistened with glass-distilled water. Each bottle was covered with a gas-tight rubber seal through which the ethylene-air mixture was injected where necessary. Incubation was at 20 °C under continuous white light or in the dark. Scarification was carried out by placing seed in conc. H2S04 for 60 s followed by five washes with water for 2 min each time.