Production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid from α-linolenic acid by permeabilized cells of recombinant Escherichia coli expressing the oleate hydratase gene of Stenotrophomonas maltophilia

Recombinant Escherichia coli, expressing the oleate hydratase gene of Stenotrophomonas maltophilia, was permeabilized by sequential treatments with 0.125 M NaCl and 2 mM EDTA. The optimal conditions for the production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid from α-linolenic acid by permeabilized cells were 35 °C and pH 7.0 with 0.1 % (v/v) Tween 40, 50 g permeabilized cells l^?1, and 17.5 g α-linolenic acid l^?1. Under these conditions, permeabilized cells produced 14.3 g 10-hydroxy-12,15(Z,Z)-octadecadienoic acid l^?1 after 18 h, with a conversion yield of 82 % (g/g) and a volumetric productivity of 0.79 g l^?1 h^?1. These values were 17 and 168 % higher than those obtained by nonpermeabilized cells, respectively. The concentration, yield, and productivity of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid obtained by permeabilized cells are the highest reported thus far.     

Production of β-apo-10′-carotenal from β-carotene by human β-carotene-9′,10′-oxygenase expressed in <Emphasis Type="Italic">E. coli</Emphasis>

The gene encoding human β-carotene-9′,10′-oxygenase, which cleaves the 9′,10′ double bond in β-carotene into β-apo-10′-carotenal, was cloned and expressed in Escherichia coli. Under aqueous conditions, the optimum organic solvent for the formation of detergent micelles was toluene. The optimum pH, temperature, detergent type, and the optimum concentrations of detergent, substrate, and enzyme for β-apo-10′-carotenal production were 8.0, 37°C, Tween 40, 2.4%, 300 mg β-carotene/l, and 0.25 U/ml, respectively. Under the optimum conditions, 43 mg β-apo-10′-carotenal/l was produced after 21 h with a conversion of 14%. This is the first report to describe the enzymatic production of β-apo-10′carotenal.     

On the paper by E. R. Muslikhov,I. F. Sukhanova,and P. V. Avdonin entitled “Arachidonic acid activates release of calcium ions from reticulum via ryanodine receptor channels in C2C12 skeletal myotubes” published in Biochemistry (Moscow), Vol. 79, No. 5, pp. 435–439 (2014)

A recent study published by Muslikhov et al. (Biochemistry (Moscow), 79, 435–439 (2014)) showed that arachidonic acid increases cytosolic Ca²⁺ concentrations in C2C12 skeletal myotubes mainly via activation of the ryanodine (RY) receptor 1. These results are consistent with the data from another study demonstrating that arachidonic acid targets RY receptor 2 in clonal and primary pancreatic β-cells (Woolcott et al., 2006). A novel and intriguing finding by Muslikhov’s group is that arachidonic acid also appears to activate the two-pore ion channel (TPC), suggesting that arachidonic acid could be a mediator in the interaction between TPCs and RY receptors.