Microcystin-RR (MCRR), a very widespread toxic microcystin in China, has previously been proved to induce sensitive apoptosis in Carassius auratus lymphocytes in vitro. This study focused on the role of intracellular Ca(2+), mitochondrial membrane potential, reactive oxygen species, and intracellular ATP in the mechanism of MCRR-induced apoptotic toxicity to fish lymphocytes. Compared with controls, administration of MCRR (10 nmol L(-1)) caused a massive calcium influx resulting in elevation of reactive oxygen species (ROS), rapid disruption of mitochondrial membrane potential (DeltaPsim), and depletion of ATP. This study provided a possible mechanism for the cytotoxicity of microcystins to fish lymphocytes.

Tai Lake is the third largest freshwater lake in China with annual cyanobacteria blooms. Microcystins produced by these blooms have serious health risks for populations surrounding the lake, especially for people living on Tai Lake, because they usually drink raw lake water after a simple alum treatment. This study presents data on the detection and identification of microcystins in waters used for daily life by people living on Tai Lake, during the cyanobacterial blooming in July 2007. The health risks from drinking these microcystin-polluted waters were also calculated. The main microcystins detected by high-performance liquid chromatography-electrospray ionization mass spectrometry in the water samples collected from two parts of Tai Lake (Wuli Lake and Meiliang Bay) were MC-LR (4.33-12.27 lg/L), MC-RR (8.36-16.91 lg/L) and MC-YR (1.41-5.57 lg/L). Risk assessment showed that the drinking water simply treated by alum was not safe. The lowest calculated hazards ratios in all water samples was 6.4, which indicated that the risk of microcystins exposure from drinking water was over six times higher than the tolerable daily intake (TDI) recommended by The World Health Organization (WHO). Further studies should be conducted to elucidate the relationships between the epidemiology of people living on Tai Lake and microcystins exposure from drinking water. # 2008 Wiley Periodicals, Inc. Environ Toxicol 24: 82-86, 2009

Plant peptides secreted as signal molecular to trigger cell-to-cell signaling are indispensable for plant growth and defense processes. Preciously, it is regraded some plant peptides function in plant growth and development, whereas others regulate defense response in plant-microbe interactions. However, this prejudice is got rid due to more and more evidence showed growth-related plant peptides also exhibit bifunctional roles in plant defense response against different microbial pathogens. Here we provide a mini-review of reported types of plant peptides, including their basic information, reported receptor ligands, and especially direct or indirect roles in plant immune responses.