Raphidiopsis raciborskii is a freshwater, potentially toxigenic cyanobacterium, originally described as a tropical species that is spreading to northern regions over several decades. The ability of R. raciborskii to produce cyanotoxins – in particular the alkaloid cylindrospermopsin (CYN), which is toxic to humans and animals – is of serious concern. The first appearance of R. raciborskii in Russia was noted in Lake Nero in the summer of 2010. This is the northernmost (57°N) recorded case of the simultaneous presence of R. raciborskii and detection of CYN. In this study, the data from long-term monitoring of the R. raciborskii population, temperature and light conditions in Lake Nero were explored. CYN and cyr/aoa genes present in environmental samples were examined using HPLC/MS-MS and PCR analysis. A R. raciborskii strain (R104) was isolated and its morphology, toxigenicity and phylogeography were studied. It is supposed that the trigger factor for the strong development of R. raciborskii in Lake Nero in summer 2010 may have been the relatively high water temperature, reaching 29–30 °C. Strain R. raciborskii R104 has straight trichomes and can produce akinetes, making it morphologically similar to European strains. Phylogeographic analysis based on nifH gene and 16S-23S rRNA ITS1 sequences showed that the Russian strain R104 grouped together with R. raciborskii strains isolated from Portugal, France, Germany and Hungary. The Russian strain R104 does not contain cyrA and cyrB genes, meaning that it – like all European strains – cannot produce CYN. Thus, while recent invasion of R. raciborskii into Lake Nero has occurred, morphological, genetic, and toxicological data supported the spreading of this cyanobacterium from other European lakes. Detection of CYN and cyr/aoa genes in environmental samples indicated the cyanobacterium Aphanizomenon gracile as a likely producer of CYN in Lake Nero. The article also discusses data on the global biogeography of R. raciborskii. Genetic similarity between R. raciborskii strains isolated from very remote continents might be related to the ancient origin of the cyanobacterium inhabiting the united continents of Laurasia and Gondwana, rather than comparably recent transoceanic exchange between R. raciborskii populations.

Raphidiopsis raciborskii是一种淡水，可能是产毒素的蓝细菌，最初被描述为热带物种，几十年来一直传播到北部地区。R. raciborskii产生氰毒素的能力，特别是对人和动物有毒的生物碱cylindrospermopsin（CYN）的能力受到严重关注。R. raciborskii在俄罗斯首次露面是在2010年夏天在尼罗湖。这是记录到的最北端（57°N）同时存在R. raciborskii和CYN的病例。在这项研究中，探索了对尼罗湖中R. raciborskii种群，温度和光照条件进行长期监测的数据。CYN和使用HPLC / MS-MS和PCR分析检查环境样品中存在的cyr / aoa基因。分离了R. raciborskii菌株（R104），并对其形态，产毒性和系统地理学进行了研究。据推测，导致尼罗湖R.raciborskii在2010年夏季强劲发展的触发因素可能是相对较高的水温，达到29–30°C。R. raciborskii R104菌株具有直的毛状体，可以产生秋葵，使其在形态上与欧洲菌株相似。基于nifH基因和16S-23S rRNA ITS1序列的系统谱分析表明，俄罗斯菌株R104与R. raciborskii一起分组从葡萄牙，法国，德国和匈牙利分离的菌株。俄罗斯菌株R104不包含cyrA和cyrB基因，这意味着与所有欧洲菌株一样，它不能产生CYN。因此，尽管最近发生了拉氏梭菌入侵尼罗湖的事件，但形态学，遗传学和毒理学数据支持了这种蓝细菌从其他欧洲湖泊的扩散。对环境样品中CYN和cyr / aoa基因的检测表明，蓝藻细菌Aphanizomenon可能是Nero湖中CYN的产生者。本文还讨论了R. raciborskii的全球生物地理数据。R.raciborskii之间的遗传相似性从非常偏远的大陆中分离出的菌株可能与居住在月桂亚大陆和冈瓦纳大陆上的蓝细菌的古老起源有关，而不是与最近的R. raciborskii种群之间的越洋交换有关。