THE EFFECT OF CHRONIC TOXICITY OF COPPER ON THE ACTIVITY OF BALBIANI RINGS AND NUCLEOLAR ORGANIZING REGION IN THE SALIVARY-GLAND CHROMOSOMES OF CHIRONOMUS-NINEVAH LARVAE

The effect of copper on the activity of Balbiani rings (BR1 and BR2) and nucleolar organizing region (NOR) in chromosome IV of the salivary gland of the 4th instar larvae of Chironomus ninevah has been investigated. Sublethal concentrations, i.e. 0.02, 0.1, 0.15 and 0.2 mg litre-1 suppress the activity of BR1, and are statistically significant. The same concentrations reduced the activity of BR2 and NOR, but without significant differences, except 0.1 mg litre-1 which was significant. The purpose of this work was to evaluate the effect of chronic toxicity of Cu2+ on the expression of gene activity of midge salivary gland chromosomes. Although there may be many more aquatic organisms that are more sensitive to copper, this midge was selected as a biological indicator species because of its association with benthic sediments.