Microcystin-LR alters the growth, anthocyanin content and single-stranded DNase enzyme activities in Sinapis alba L. seedlings

Microcystin-RR-induced apoptosis in tobacco BY-2 cells

“…It has been reported that 22 mg/L microcystin-LR was needed to induce necrosis of mustard cotyledon (M-Hamvas et al, 2002). In this work, above 1 mg/L microcystin-RR was needed to induce apoptosis in tobacco BY-2 suspension cells (Fig.…”

“…In natural conditions, the microcystin concentration is usually very low, but in certain circumstances, its concentration can amount to 1.3-1.8 mg/L (Jones and Orr, 1994). Due to the fact that different plants have different susceptibility to microcystin exposure (Pflugmacher et al, 1999;McElhiney et al, 2001;M-Hamvas et al, 2002), it is possible that microcystin induces apoptosis in certain tissues of some aquatic plants after long time of low-concentration microcystin exposure. If this is the case, the results may have impact on understanding the role of microcystin in eutrophic freshwater ecosystem.…”

Morphological and ultrastructural changes in tobacco BY-2 cells exposed to microcystin-RR

“…These ultrastructural changes in cells in the high-concentration group were consistent with the symptoms of cell necrosis (Noodén, 2004). Mustard seedlings also showed necrosis of cotyledons exposed to MC-LR (M-Hamvas et al, 2003).…”

“…Romanowska-Duda and Tarczynska (2002) found that microcystin-LR inhibited the growth of an aquatic macrophyte (Spirodela oligorrhiza) and decreased chlorophyll content. M-Hamvas et al (2003) found that fresh weight, plant length, the extent of lateral root formation, and anthocyanin content were lower in seedlings of white mustard (Sinapis alba L.) that had been treated with microcystin-LR. The commonly accepted mechanism of action of MCs in plants is inhibition of protein phosphatase type-1 and -2A.…”

A laboratory study on risk assessment of microcystin-RR in cropland

“…The toxin was found to have little effect on growth for up to 18 days, but impaired the development of the roots of exposed plants, causing them to take up approximately 30% less growth medium than those grown in the absence of toxin. Hamvas et al (2002) described the inhibitory effects of MC-LR on growth, lateral root formation, development, and anthocyanin content of mustard seedlings (a model system) and proved that MC-LR induces necrosis on mustard seedlings, in particular on the cotyledons and in tissues with high ssDNase activity. During exposure of C. demersum to the cyanobacterial toxin MC-LR at a concentration of 5.0 mg/L, an elevation of microsomal and cytosolic glutathione S-transferase was observed, indicating the initiation of the glutathione-toxin conjugate formation.…”