Induction of micronuclei and sister chromatid exchange in bone-marrow cells and abnormalities in sperm of Algerian mice (Mus spretus) exposed to cadmium, lead and zinc

As a consequence of human activities, large amounts of cadmium, lead and zinc are released in the environment, often simultaneously. The aim of this study was to investigate under experimental conditions the DNA damage induced in Algerian mice (Mus spretus) exposed to cadmium (Cd), lead (Pb) and zinc (Zn) separately, or in selected combinations. Three cytogenetic end points were considered: the frequencies of micronucleated cells (MN) and sister chromatid exchange (SCE) in the bone marrow and the frequency of sperm abnormalities. Mice were treated by intraperitoneal (i.p.) injections with 5 or 10 doses of aqueous solutions of cadmium acetate, lead acetate and zinc acetate in concentrations corresponding to 1/10 of the LD50, respectively, 21.5, 0.46 and 1.5 mg/kg bw. The control groups were injected in the same way with distilled water.With only one exception (Cd + Zn group treated with 5 doses), the results show a significant increase of MN in all groups for both treatments (5 and 10 doses). Similarly, the results concerning the SCE revealed a statistically significant increase in all treated animals, with the exception of the Zn group treated with 5 doses. The number of sperm abnormalities was significantly higher in animals treated with 5 doses, except in the group Pb + Zn. In animals treated with 10 doses the number of sperm abnormalities was always statistically higher compared with controls.This study indicates that cadmium, lead and zinc can induce MN, SCEs and sperm abnormalities in Algerian mice and that the clastogenic potential is dependent on the time of exposure and the interaction between the three elements, confirming the environmental damage that may result from the simultaneous action of several metals. Most relevant is the toxic potential for Zn, related with the dose, which may compromise its protective effect against other metal contaminations, such as cadmium.     

Effects of NaCl salinity in vivo and in vitro on ribonuclease activity of Vigna unguiculata cotyledons during germination

Pitiuba bean [ Vigna unguiculata (L.) Walp.] seeds were sown in water or. in 0.1 M NaCl. Seedling growth and cotyledon nucleic acid mobilization were delayed by NaCl salinity. The differences in cotyledonary RNase activity between seeds sown in water and in NaCl solutions suggest that salinity delays the activation and/or de novo synthesis of the enzyme. Cotyledon extracts were subjected to gel filtration through Sephadex G-100, and RNase activity measured. Only one cotyledonary RNase appeared during germination, and salinity did not induce any change in molecular weight of the enzyme. Salinity inhibited 45% of the specific activity of the RNase on the 5th day of the experimental period. The same salt concentration (0.1 M NaCl) added in vitro inhibited only 8 % of the specific activity of the enzyme. This difference may indicate that NaCl in vivo affects mainly the de novo synthesis of the RNase.     

Monte Carlo simulation program for ecosystems

A Monte Carlo computer simulation program is designed in orderto describe the spatial and time evolution of a population ofliving individuals under preassigned environmental conditionsof energy. The simulation is inspired by previous techniquesdeveloped in physics — in particular, in molecular dynamicsand simulations of liquids — and it already provides somenew insights regarding macroscopic deterministic models in ecologyand concerning eventual control of artificial biomass productionplants. Received on July 15, 1986; accepted on October 9, 1986