A Soluble Aggregated Thermophile Metalloaminopeptidase Produced by an Alcalophile Strain of Bacillus halodurans

Abstract: H4 strain isolated from Lake Bogoria was found to be Bacillus halodurans. The Bacteria produced an extracellular peptidase activity toward substrates Ile-pNA, Met-pNA and Val-pNA. It also hydrolyzed small peptides. A purification procedure including ion-exchange chromatography ion exchange DEAE and sizeexclusion chromatography followed by Sodium dodecyl sulphate-polyacrymalide gel electrophoresis (SDS-PAGE) revealed the aggregated form of the enzyme. The three substrates are hydrolyzed by a single catalytic site. The enzyme inactivated by bestatin, and 1,10-phenanthroline is a metalloaminopeptidase whose activity is maximal at pH 9.0 and 65ºC

Characterisation of purple acid phosphatase from breadfruit (Artocarpus communis) seeds

ABSTRACT Objectives: To investigate the biochemical properties, physiological role and possible application of a purple acid phosphatase isolated from breadfruit (Artocarpus communis) seeds. Methodology and results: An acid phosphatase was purified 13.7-fold to apparent homogeneity from breadfruit (Artocarpus communis) seeds, using successive chromatographies on DEAE-Sepharose Fast-flow, Sephacryl S-100 HR, and phenyl Sepharose 6 Fast-flow. The enzyme was a purple acid phosphatase (λmax = 510 nm) that appeared to be a monomeric protein with molecular weight of approximately 27.3 kDa by SDS PAGE. The purple acid phosphatase was optimally active at pH 5.5 and 55°C, but strongly inhibited by molybdate, vanadate, phosphate and zinc. Moreover it did not require divalent cations for catalysis. This phosphatase showed wide substrate specificity with high affinity for sodium pyrophosphate, suggesting that pyrophosphate could be its potential physiological substrate. The enzyme also hydrolyzed sodium phytate. Potential application of finding: The purified enzyme could be applied in the mineral fertilizers industry or as a food additive for monogastric animals, e.g. pigs, in farming systems

Comparative study of earthworm communities, microbial biomass, and plant nutrient availability under 1-year Cajanus cajan (L.) Millsp and Lablab purpureus (L.) Sweet cultivations versus natural regrowths in a guinea savanna zone

In tropical savannas where soils are generally sandy and nutrient poor, organic farming associated with enhanced soil biological activity may result in increased nutrient availability. Therefore, legumes have been introduced in the humid savanna zone of Cte d'Ivoire, owing to their ability to fix atmospheric N and to continually supply soil with great quantity of organic materials in relatively short time. The main objective of this study was to assess the influence of two legume (Cajanus cajan and Lablab purpureus) cultivations on earthworm communities and P and N availability. Trials were carried out under farmers' field conditions; C. cajan was planted on savanna soils (trial 1) while L. purpureus was established on new Chromolaena odorata-dominated fallow soils (trial 2). Native vegetations were considered as controls. Changes in soil properties (earthworm abundance and diversity, microbial biomass carbon (MBC), and plant available P and N) were assessed using the biosequential sampling. After 1 year, both the legume stands showed a significantly higher density of earthworms, compared with the respective controls. This trend was linked to an increase in the abundance of the detritivores Dichogaster baeri Sciacchitano 1952 and Dichogaster saliens Beddard 1893, and the polyhumic Stuhlmannia zielae Omodeo 1963. Equally, legume had beneficial impacts on the average number of earthworm species, the Shannon-Weaver index of diversity and MBC in savanna (trial 1). Available P and ammonium significantly increased under both legume cultivations and were significantly and concurrently linked to litter quality and earthworm activities as shown by multiple regressions. As a result, legumes could improve nutrient availability in the sandy soils of central Cte d'Ivoire by positively affecting soil biological activity and this could bring farmers to cultivate crops on savanna lands

Physicochemical Changes in Bulbils of Two Cultivars of Dioscorea bulbifera During the Ripening Period

Abstract: This study was carried out in order to determine and compare changes in physicochemical properties of bulbils from two cultivars (yellow and mauve) of Dioscorea bulbifera at different periods during the growth. The tests were performed on the bulbils from one to six months of age. The results showed that the weight of bulbils of both cultivars increased. They were ranged on fresh weight basis, from 31.88±13.1 g to 314.93±16.87 g for yellow cultivar and from 10.26±5.17 to 61±14.17 g for mauve cultivar. Starch content, like lipids, total and reducing sugars, cellulose and ash increased also. Starch was the most abundant chemical component with values ranged from 62.09±5.45 to 78.5±5.2% and from 60.56±3.05 to 70.57±6.87%, (on dry weight basis) for yellow and mauve cultivar respectively. Potassium is the most abundant mineral. It value increased during the growth time and ranged (in mg per 100 g dry weight) from 109.2±0.30 to 451.9±0.41 and from 89.66±0,5 to 403.45±0.6 for yellow and mauve cultivar respectively. Bulbils physiological maturity might be set at sixth month during the growth time as some components like Zn, Mg and protein reached a critical level after six months