[D-Leu]MC-LR Has Lower PP1 Inhibitory Capability and Greater Toxic Potency than MC-LR in Animal and Plant Tissues.

Two microcystins, MC-LR and [D-Leu]MC-LR, present in La Plata Basin blooms, are differentiated by substitution of D-Alanine for D-Leucine at position 1. Our objective was to evaluate acute toxicity of [D-Leu]MC-LR and MC-LR in mice (N:NIH Swiss) and beans (). We observed variations in [D-Leu]MC-LR lethal doses with respect to those reported for MC-LR (100 μg/kg), with an increased liver/body weight ratio and intrahepatic hemorrhages in mice exposed to 50-200 μg [D-Leu]MC-LR/kg and slight steatosis after a single 25 μg [D-Leu]MC-LR/kg i.

[D-Leu]MC-LR and MC-LR: A Small-Large Difference: Significantly Different Effects on L. (Fabaceae) Growth and Phototropic Response after Single Contact during Imbibition with Each of These Microcystin Variants.

[D-Leu]MC-LR and MC-LR, two microcystins differing in one amino acid, constitute a sanitary and environmental problem owing to their frequent and concomitant presence in water bodies of the Americas and their association with human intoxication during recreational exposure to cyanobacterial bloom. Present in reservoirs used for irrigation as well, they can generate problems in the development of crops such as , of nutritional and economic interest to the region. Although numerous works address the toxic effects of MC-LR, information on the toxicity of [D-Leu]MC-LR is limited.