Changes in serum protein lipid and electrolyte levels in rabbits at mid-altitude

Micronucleus test in fish cells: a bioassay for in situ monitoring of genotoxic pollution in the marine environment

To evaluate the use of native fish species for assessing genotoxic pollution in the marine environment, micronucleus (MN) analysis was performed in peripheral blood erythrocytes and gill cells of the grey mullet (Mugil cephalus) from three sampling stations off the southeastern Mediterranean coast of Turkey. The frequencies of blebbed, notched, and lobed nuclei and binucleated cells also were evaluated in peripheral erythrocytes. The sampling sites were chosen on the basis of pollution levels; Karaduvar harbor, contaminated by different types of industrial effluents, and Mersin harbor, mainly contaminated by aromatic hydrocarbons, were selected as polluted areas. Erdemli harbor, a relatively unpolluted site, was used as the control area. Sampling was carried out at four different seasons. The frequencies of both micronuclei and other nuclear abnormalities (NAs) in mullets captured from polluted areas were significantly higher than those in mullets from the reference area. In general, gill cells had considerably higher MN frequencies than did erythrocytes, and genotoxic responses were higher in summer than in winter. The results of this study indicate that the MN test in fish is a suitable biomarker for in situ monitoring of genotoxic pollution in the marine environment. As demonstrated in this study, NAs other than micronuclei are also useful indices of chemical exposure and toxic responses. Therefore, measuring both micronuclei and NAs may increase the sensitivity of the test system.

Evaluation of the genotoxic and cytochrome P450 monooxygenase-inhibitory potential of Dicuran on procaryotic and eucaryotic test systems

The effect of the herbicide Dicuran 500 FL (formulated product) on the phenotypical and genotypical changes in procaryotic and eucaryotic organisms was investigated using short-term tests for detecting genotoxins. Since pesticides discharged in the water environment can modulate the mixed-function monooxygenases (MFO) detoxification system of water organisms, the in vivo and in vitro effects of Dicuran on hepatic cytochrome P450 (cyt P450) monooxygenase activities were also examined in juvenile carp (Cyprinus carpio L.). By measuring the activities of MFO in experimental carp exposed to Dicuran an attempt was made to establish whether Dicuran could be bioactivated by MFO into ultimate mutagens. Our results on the bacterial strains Salmonella typhimurium TA100 and TA98 show that Dicuran does not possess either mutagenic or premutagenic characteristics. The micronucleus test on the erythrocytes of experimental carp did not establish any clastogenic effect either. However, Dicuran significantly inhibited the MFO activity of 7-ethoxyresorufin-O-deethylase (EROD) and benzo[a]pyrene monooxygenase (BaPMO) in the liver of experimental carp in vitro, as well as in in vivo conditions. These findings demonstrate the potentially damaging effect of Dicuran on the xenobiotic metabolizing enzyme systems of fish, and suggest the applicability of described methods for the prediction of the ecotoxicological significance of the presence of pesticides in the water environment.

Variability in the size, composition, and function of insect flight muscles

In order to fly, insects require flight muscles that constitute at least 12 to 16% of their total mass, and flight performance increases as this percentage increases. However, flight muscles are energetically and materially expensive to build and maintain, and investment in flight muscles constrains other aspects of function, particularly female fecundity. This review examines ways in which insects vary the size of their flight muscles, and how variation in the relative size and composition of flight muscles affects flight performance. Sources of variability in flight muscle size and composition include genetic differences within and between species, individual phenotypic responses to environmental stimuli, and maturational changes that occur before and during the adult stage. Insects have evolved a wide variety of ways to adjust flight muscle size and contractile performance in order to meet demands imposed by variation in life history and ecology.