scholarly journals Alkaline O→N-transacylation. A new method for the quantitative deacylation of phospholipids

1981 ◽  
Vol 195 (1) ◽  
pp. 301-306 ◽  
Author(s):  
N G Clarke ◽  
R M C Dawson

1. Quantitative O-deacylation of phospholipids has been achieved by incubation with a reagent containing monomethylamine, methanol and water. The reaction is primarily an O leads to N-transacylation with N-methyl fatty acid amides being formed. 2. The reagent can be removed easily by volatilization and under defined conditions no secondary decomposition of the phosphorus-containing deacylation products occurs. 3. The water-soluble phosphorus compounds derived by deacylation of mammalian tissue O-diacylated phospholipids have been completely separated by a single-dimensional paper ionophoresis with a volatile pH9 buffer. 4. The O-deacylated alkyl and alkenyl phospholipids have been examined by t.l.c. before and after catalytic hydrolysis with Hg2+. 5. A complete analysis of rat brain phospholipids by the above methods agrees closely with that obtained by other procedures.

2005 ◽  
Vol 30 (3-4) ◽  
pp. 491-505 ◽  
Author(s):  
Anne-Marie Caminade ◽  
Jean-Pierre Majoral

2021 ◽  
Vol 4 (28) ◽  
pp. 159-182
Author(s):  
L.A. Chaikovskaya ◽  
◽  
O.L. Ovsienko ◽  

Phosphorus is an essential plant nutrient involved in plants’ growth and development, accelerated formation of reproductive organs and other important factors for obtaining high and stable crop yields and, therefore, high-quality products. Easily absorbed phosphorus compounds obtained from soil or fertilizers are the most valuable for plants. One of the promising directions for improving the phosphorus nutrition of agricultural crops is biological phosphate mobilization that is carried out by soil microorganisms – bacteria and filamentous fungi (micromycetes). They contribute to the conversion of poorly soluble phosphorus compounds into forms accessible to higher plants. The effect of microorganisms on plants in terms of improving their mineral nutrition, in particular phosphorus, was reviewed in this article. We analysed domestic and foreign literature sources (over the last 15 years) focused on the biodiversity of soil phosphate-mobilizing microorganisms and their influence on converting insoluble phosphate to soluble forms. The features of the mechanisms of biotransformation of organic and mineral phosphates by soil microorganisms and the main criteria for screening effective isolates able to convert poorly soluble phosphorus compounds into forms available for plants were described in detail. This review also demonstrates that several microorganisms belonging to different taxonomic groups (bacteria and micromycetes) are recognized as powerful phosphate solubilizers or bioconverters of poorly soluble phosphorus compounds into water-soluble forms. We also surveyed scientific works, in which the practical application of effective strains of microorganisms that transform unavailable phosphorus compounds into available for plants was studied; and those, in which the role of microorganisms in increasing the availability of phosphorus for agricultural plants and their productivity improvement was demonstrated. A comprehensive description of microbial preparations “Agrofil”, “Biovays”, “Ekophosphorin”, “Ekovital”, “Biophosphorin”, “Albobacterin”, “Polymiksobacterin”, “Agrobacterin”, “Phosphostim”, “Fitostimophos”, “Agromik”, “Baktopin” based on phosphate-mobilizing microorganisms, developed and used in various countries to optimize mineral nutrition of cultivated plants, is given.


2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.


1997 ◽  
Vol 35 (2-3) ◽  
pp. 131-138 ◽  
Author(s):  
Pirjo-Riitta Rantala ◽  
Hannu Wirola

The aim of the study was to determine if solid, slightly soluble compounds can be used as nutrient source in activated sludge treatment plants instead of liquid phosphoric acid. Four different solid materials were tested in lab-scale solubility tests to find compounds which are least soluble. Two materials were chosen for further studies: apatite and raw phosphate. The use of apatite and raw phosphate as nutrient source was studied in lab-scale activated sludge reactors along with a control reactor where phosphorus was added in liquid form. The phosphorus dosage, measured as elementary phosphorus, was the same for all three reactors. The reactors were fed with pre-clarified chemi-thermomechanical pulp mill (CTMP) wastewater. There were no significant differences in the reductions of organic matter between the three reactors. The mean effluent concentration of total phosphorus was 3 mg P/l in the control reactor and less than 1 mg P/1 in the other two reactors. The soluble phosphorus concentration was more than 2 mg P/l in the control reactor and less than 0.5 mg P/l in the other two. Apatite was an even better nutrient source than raw phosphate. Further lab-scale tests were conducted using two different grain sizes of apatite. No significant differences were found between the studied grain sizes (&lt;0.074 mm and 0.074 mm-0.125 mm). Apatite was then used in full-scale at a CTMP-mill two different times. The experiments showed that the mean concentrations of phosphorus can be reduced radically by using apatite as a nutrient source instead of liquid phosphorus. Solid phosphorus compounds are a viable alternative to reduce the phosphorus load from forest industry wastewater treatment plants.


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