Tolerance,arsenic uptake,and oxidative stress in Acacia farnesiana under arsenate-stress

Acacia farnesiana is a shrub widely distributed in soils heavily polluted with arsenic in Mexico. However, the mechanisms by which this species tolerates the phytotoxic effects of arsenic are unknown. This study aimed to investigate the tolerance and bioaccumulation of As by A. farnesiana seedlings exposed to high doses of arsenate (AsV) and the role of peroxidases (POX) and glutathione S-transferases (GST) in alleviating As-stress. For that, long-period tests were performed in vitro under different AsV treatments. A. farnesiana showed a remarkable tolerance to AsV, achieving a half-inhibitory concentration (IC₅₀) of about 2.8 mM. Bioaccumulation reached about 940 and 4380 mg As·kg^?1 of dry weight in shoots and roots, respectively, exposed for 60 days to 0.58 mM AsV. Seedlings exposed to such conditions registered a growth delay during the first 15 days, when the fastest As uptake rate (117 mg kg^?1 day^?1) occurred, coinciding with both the highest rate of lipid peroxidation and the strongest up-regulation of enzyme activities. GST activity showed a strong correlation with the As bioaccumulated, suggesting its role in imparting AsV tolerance. This study demonstrated that besides tolerance to AsV, A. farnesiana bioaccumulates considerable amounts of As, suggesting that it may be useful for phytostabilization purposes.     

Early hematologic changes in rhesus macaques (Macaca mulatta) infected with pathogenic and nonpathogenic isolates of SIVmac

Early hematologic changes were studied over a 14 day period in three groups of six rhesus macaques intravenously infected with pathogenic and nonpathogenic isolates of SIVmac. Abnormalities in blood included a mild blood loss anemia, sporadic lymphopenia, and variable CD4+ and CD8 + T lymphocyte numbers. Prominent bone marrow findings in macaques inoculated with pathogenic uncloned SIVmac and molecularly cloned pathogenic SIVmac-239 were hypercellularity, myeloid and megakaryocytic hyperplasia, and lymphoid aggregates. Infrequent mild morphologic abnormalities were present in macaques infected with a nonpathogenic molecular clone, SIVmac-1A11.