[Spectroscopic study of the structural changes of scorpion hemocyanin, induced by pH variations and addition of various salts]

[Survey of Arsenic/Heavy Metals and Pesticide Residues in Edible Insects for Human Consumption or Supplied in Japan]

Arsenic (As) and heavy metals (Cd, Hg, Pb, and Cu) and pesticide residues in 14 edible insects were investigated. The maximum levels of elements were 6.15 for As, 0.82 for Cd, 0.50 for Hg, 0.67 for Pb, and 297.7 ppm for Cu. Fenobucarb (or BPMC) has been quantified through GC- and LC-MS/MS analysis at a concentration of approximately 3 ppm. Further studies of the contaminants may help ensure the safety of edible insect consumption.

Antioxidant activity of hemocyanin; a pulse radiolysis study

In order to determine the reactivity on hemocyanin from Androctonus australis, the reaction of superoxide anion has been investigated using pulse radiolysis. The kinetics of O2- decays have been studied in aqueous buffered media at various basic pH (8, 8.5 and 9), first in the absence and then in the presence of hemocyanin (in oxygenated solutions containing formate anion 0.16 mol.l-1). We have shown that, in the presence of hemocyanin, O2- decay is a first-order process whose apparent rate constant is proportional to protein concentration (10(-7) to 10(-6) mol.l-1) and pH independent between 8 to 9. A second-order rate constant of 3.5 +/- 0.1.10(7) mol-1.l.s-1, has been deduced for the catalytic rate constant of hemocyanin with O2-. Meanwhile, this activity is smaller than that described for free copper, eukaryotic Cu-Zn-SOD or some copper chelates. We have verified that apohemocyanin--the copper deprived protein--does not exhibit such an activity vs. SOD (superoxide dismutase).