Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, PR China.
Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia.
Toxicon. 2020 Mar;176:47-54. doi: 10.1016/j.toxicon.2020.01.013. Epub 2020 Jan 23.
Cyanobacteria species are sensitive to many plant allelochemicals, such as pyrogallol. However, little attention has been paid to the relative effects of these xenobiotics on co-occurring toxigenic and non-toxigenic cyanobacterial strains, despite their co-existence in blooms. Hence, the responses of one toxigenic (TS2) and two non-toxigenic (NS1, NS2) Microcystis aeruginosa strains to pyrogallol were tested under three conditions: mono-culture and co-cultured either directly or separately by dialysis membrane. The study showed that the inhibitory effects of pyrogallol on the growth and photosynthetic yield (Fv/Fm) of either toxigenic or non-toxigenic M. aeruginosa strains were lower in direct and dialysis co-culture conditions than those in mono-culture conditions. This result indicated that chemical-mediated reciprocal effects occur between the co-existing toxigenic and non-toxigenic strains. The toxigenic M. aeruginosa strain was more sensitive to pyrogallol than the non-toxigenic strains in both mono- and co-culture systems, though whether this outcome is due to the former's toxigenic status is unclear. Intracellular microcystin-LR (MC-LR) concentrations of the toxigenic strain decreased after pyrogallol addition in both mono- and co-culture systems, whereas extracellular MC-LR concentrations increased. This finding may reflect the cell damage of M. aeruginosa because of the pyrogallol. At the same initial number of cells, the extracellular MC-LR concentration released from the same amount of TS2 cells in mono-culture was slightly higher than that in dialysis co-culture conditions. Overall, this study shows that plant allelochemicals may have the potential to reduce bloom toxicity by reducing the proportion of toxigenic cyanobacterial strains, and the effects of co-existing strains must be considered when assessing the effects of plant allelochemicals on target strains.
蓝藻物种对许多植物化感物质敏感，如焦倍酚。然而，尽管它们在水华中共存，但对于这些外来生物对共存的产毒和非产毒蓝藻菌株的相对影响，人们关注甚少。因此，本研究测试了一株产毒（TS2）和两株非产毒（NS1、NS2）铜绿微囊藻对焦倍酚的响应，在三种条件下进行：单培养以及通过透析膜直接或分别共培养。研究表明，与单培养条件相比，在直接和透析共培养条件下，焦倍酚对产毒或非产毒铜绿微囊藻菌株生长和光合产量（Fv/Fm）的抑制作用较低。这一结果表明，共存的产毒和非产毒菌株之间存在化学介导的相互作用。在单培养和共培养系统中，产毒铜绿微囊藻菌株对焦倍酚的敏感性均高于非产毒菌株，尽管这是否是由于前者的产毒状态尚不清楚。在单培养和共培养系统中，产毒株细胞内微囊藻毒素-LR（MC-LR）浓度在添加焦倍酚后均降低，而细胞外 MC-LR 浓度增加。这一发现可能反映了铜绿微囊藻因焦倍酚而受到的细胞损伤。在相同的初始细胞数下，从相同数量的 TS2 细胞在单培养中释放的细胞外 MC-LR 浓度略高于透析共培养条件。总的来说，本研究表明，植物化感物质通过降低产毒蓝藻菌株的比例，可能具有降低水华毒性的潜力，在评估植物化感物质对靶菌株的影响时，必须考虑共存菌株的影响。
