Unique Diversity of Sting-Related Toxins Based on Transcriptomic and Proteomic Analysis of the Jellyfish Cyanea capillata and Nemopilema nomurai (Cnidaria: Scyphozoa)

The scyphozoan jellyfish Cyanea capillata and Nemopilema nomurai are common blooming species in China. They possess heterogeneous nematocysts and produce various types of venom that can elicit diverse sting symptoms in humans. However, the differences in venom composition between the two species remain unclear. In this study, a combined transcriptomic and proteomic approach was used to identify and compare putative toxins in penetrant nematocysts isolated from C. capillata and N. nomurai. A total of 53 and 69 putative toxins were identified in C. capillata nematocyst venom (CnV) and N. nomurai nematocyst venom (NnV), respectively. These sting-related toxins from both CnV and NnV could be grouped into 10 functional categories, including proteinases, phospholipases, neurotoxins, cysteine-rich secretory proteins (CRISPs), lectins, pore-forming toxins (PFTs), protease inhibitors, ion channel inhibitors, insecticidal components, and other toxins, but the constituent ratio of each toxin category varied between CnV and NnV. Metalloproteinases, proteases, and pore-forming toxins were predominant in NnV, representing 27.5%, 18.8%, and 8.7% of the identified venom proteins, respectively, while phospholipases, neurotoxins, and proteases were the top three identified venom proteins in CnV, accounting for 22.6%, 17.0%, and 11.3%, respectively. Our findings provide comprehensive information on the molecular diversity of toxins from two common blooming and stinging species of jellyfish in China. Furthermore, the results reveal a possible relationship between venom composition and sting consequences, guiding the development of effective treatments for different jellyfish stings.