In the present work we have partially characterized an ecto-phosphatase activity in Crithidia deanei, using viable parasites. This enzyme hydrolyzed p-nitrophenylphosphate at a rate of 3.55 +/- 0.47 nmol Pi/h x 10(8) cells. The dependence on p-NPP concentration shows a normal Michaelis-Menten kinetics for this phosphatase activity and the value of the apparent Km for p-NPP was 5.35 +/- 0.89 mM....

In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capab...

The modABC gene products constitute the molybdate-specific transport system in Escherichia coli. Another operon coding for two proteins which diverges from the modABCD operon has been identified. The first gene of this operon codes for a 262-amino-acid protein, designated ModE (28 kDa), and the second genes codes for a 490-amino-acid protein. ModF (54 kDa). The role of ModF has not yet been det...

Glucocorticoid-resistant mutants isolated from the glucocorticoid-sensitive human leukemic cell line CEM-C7 can be divided into three phenotypes: (a) those with almost no glucocorticoidbinding activity (r~); (b) those whose steroid-receptor complexes are unstable during attempted activation but are stabilized by the presence of sodium molybdate (acf^molybdate-sensitive); and (c) those whose ste...

The objective of the present experiments are to determine if sheep could safely consume high amount of PKC in their diets and if sheep's consumption of PKC require a chelating agent to tie up the high copper level in PKC to protect it against toxicity. Two experiments were carried out. Experiment 1, with four treatment groups of animals, using from 30 to 100% PKC, mixed with other feed ingredie...

Experiments were conducted to study the ability of surfactant-modified clinoptilolite for molybdate adsorption from aqueous solutions. Clinoptilolite was treated with some cationic surfactants. Adsorption of surfactants on zeolite surface was confirmed by chemical analysis, IR (Infra-Red Spectroscopy), DTG (Derivative Thermogravimetry) and SEM (Scanning Electron Microscopy) techniques. The modi...