Evaluation of Mycorrhizal Influence on the Development and Phytoremediation Potential of Canavalia Gladiata in Pb-Contaminated Soils

Soil contamination by heavy metals is a serious problem to humans due to its high level of toxicity. The heavy metal lead (Pb) is commonly used in industries and if the disposal of residues that contain this element is not done properly may result in tragic consequences to the organisms. In this experiment we assessed the potential of a forrage leguminous, Canavalia gladiata, to phytoremediate lead-contaminated soil under mycorrhizal influence. The experimental design was composed of 4 Pb doses (0, 250, 500, and 1000 mg kg^?1 of soil) and the plants were inoculated or uninoculated with arbuscular mycorrhizal fungi (AMF). We observed that the nodulation was severely affected by the presence of Pb independently of the mycorrhizal status; most of the elements analyzed were affected independently of the mycorrhizal status with exception of P. The mycorrhizal colonization was able to restrict the entrance of Pb in plants under high concentrations of Pb but promoted it's accumulation in both organs under intermediate concentrations of this element. Besides the mycorrhization did not promote plant growth under Pb stress, the use of this plant may be considered to be used for phytostabilization purposes.     

Binding of creatine kinase to heart and liver mitochondria in vitro

Phosphate extraction of heart mitochondria results in the release of creatine kinase. Under appropriate conditions phosphate-extracted mitochondria are able to rebind the creatine kinase, either from crude extracts or as the purified enzyme. Heart mitochondria are able to bind up to sevenfold more creatine kinase than they originally contained. The association is specific since the cytoplasmic isozyme from heart (MM) does not bind, and does not interfere with the binding of the mitochondrial isozyme even when MM is present in large excess. It is interesting that although liver mitochondria do not contain the mitochondrial isozyme of creatine kinase they are able to bind approximately the same amount of the enzyme as the heart mitochondria.     

Combination of high-performance liquid chromatography and thin-layer chromatography separation of five adducted nucleotides isolated from liver resulting from intraperitoneal administration with 7H-dibenzo[c,g]carbazole to mice

7H-Dibenzo[c,g]carbazole, DBC, is a potent environmental liver carcinogen. Liver DNA from mice treated with DBC exhibited seven distinct DBC-DNA adducts as detected by ³²P-postlabeling using multidimensional TLC. To improve quantitation and chemically characterize the adducts, DNA samples were hydrlyzed, ³²P-postlabeled and the adducts were separated from the unadducted normal nucleotides on TLC using a D1 solvent, 0.65 M sodium phosphate (pH 6.8). Adducts were eluted from the TLC plates with 4.0 M pyridinium formate, concentrated, resuspended in 50% aqueous methanol and injected onto the HPLC; five individual adduct peaks were resolved and collected by this method. This approach will prove useful to decrease analysis time and improve chemical characterization of tightly clustered DNA adducts generated in vivo.     

PAR transmittance through thick, clear freshwater ice

Measurements of photosynthetically active radiation through clear freshwater ice 154–158 cm thick varied from 14.8 to 24.8% depending, in this case, primarily on the amount of flocullent material trapped within the ice. Transmittance in one area dropped to less than 1% with the presence of a 3 cm thick snow cover. Extinction coefficients varied from 0.014 to 0.010 cm^–1.