Toxicological response of phormidium fragile to mercury

ABSTRACT

The effects of different concentrations of mercury on cyanobacterium Phormidium fragile were studied. The results revealed that dry biomass yield, protein content, chlorophyll a and carotenoids decreased with an increased concentration of mercury from 0.01 to 1.5 ppm. Also, malate dehydrogenase [MDH], glutamate dehydrogenase [GIDH] and nitrate reductase activity were affected by an increased metal concentration, whereas glutamic-oxalacetic transaminase [GOT] and glutamic-pyruvic transaminase [GFT] were hardly affected. Mercury uptake increased at the higher levels of the metal. On the other hand, all the amino acid components gradually increased with the rise of the metal level, except isoleucine, histidine and methionine which were suppressed by the smaller doses and completely disappeared by the larger doses of the metal