Jellyfish skin polysaccharides enhance intestinal barrier function and modulate gut microbiota in mice with DSS-induced colitis

Jellyfish skin polysaccharides (JSP) were isolated from Rhopilema esculentum Kishinouye and contained 55.11 % polysaccharides and 2.26 % uronic acid. To examine the anti-inflammatory, antioxidant and immunomodulatory activities of JSP...

Proteomic Analysis of the Venom of Jellyfishes Rhopilema esculentum and Sanderia malayensis

Venomics, the study of biological venoms, could potentially provide a new source of therapeutic compounds, yet information on the venoms from marine organisms, including cnidarians (sea anemones, corals, and jellyfish), is limited. This study identified the putative toxins of two species of jellyfish—edible jellyfish Rhopilema esculentum Kishinouye, 1891, also known as flame jellyfish, and Amuska jellyfish Sanderia malayensis Goette, 1886. Utilizing nano-flow liquid chromatography tandem mass spectrometry (nLC–MS/MS), 3000 proteins were identified from the nematocysts in each of the above two jellyfish species. Forty and fifty-one putative toxins were identified in R. esculentum and S. malayensis, respectively, which were further classified into eight toxin families according to their predicted functions. Amongst the identified putative toxins, hemostasis-impairing toxins and proteases were found to be the most dominant members (>60%). The present study demonstrates the first proteomes of nematocysts from two jellyfish species with economic and environmental importance, and expands the foundation and understanding of cnidarian toxins.

Chromosome-level reference genome of the jellyfish Rhopilema esculentum

Background Jellyfish belong to the phylum Cnidaria, which occupies an important phylogenetic location in the early-branching Metazoa lineages. The jellyfish Rhopilema esculentum is an important fishery resource in China. However, the genome resource of R. esculentum has not been reported to date. Findings In this study, we constructed a chromosome-level genome assembly of R. esculentum using Pacific Biosciences, Illumina, and Hi-C sequencing technologies. The final genome assembly was ∼275.42 Mb, with a contig N50 length of 1.13 Mb. Using Hi-C technology to identify the contacts among contigs, 260.17 Mb (94.46%) of the assembled genome were anchored onto 21 pseudochromosomes with a scaffold N50 of 12.97 Mb. We identified 17,219 protein-coding genes, with an average CDS length of 1,575 bp. The genome-wide phylogenetic analysis indicated that R. esculentum might have evolved more slowly than the other scyphozoan species used in this study. In addition, 127 toxin-like genes were identified, and 1 toxin-related “hub” was found by a genomic survey. Conclusions We have generated a chromosome-level genome assembly of R. esculentum that could provide a valuable genomic background for studying the biology and pharmacology of jellyfish, as well as the evolutionary history of Cnidaria.

Effects of temperature, salinity and dissolved oxygen on excystment of podocysts in the edible jellyfish Rhopilema esculentum Kishinouye, 1891

The scyphozoan jellyfish Rhopilema esculentum Kishinouye, 1891 is a species occurring in the traditional fishery in China. However, the yield of this species in fishery has rapidly declined since 1980s. The podocyst is an important phase during asexual reproduction in Scyphozoa and is considered to be potentially important to the population dynamics of jellyfish. In this study, we investigated the microstructure and effects of environmental factors on the excystment of podocysts. Podocysts of greater than 8 months of age exhibited no morphological differences compared to newly formed podocysts. Following excystment, a smooth-edged hole, probably created by enzymatic digestion was observed. Excystment sharply increased when the water temperature was higher than 18°C, suggesting that temperature ranging from approximately 13-18°C triggers the excystment of podocysts in R. esculentum. Stepwise temperature variation suggested that cooling was much more effective than warming in the induction of R. esculentum podocysts to excyst. The optimal salinity and dissolved oxygen (DO) conditions for excystment were observed to be 20‰ and 6 mg O2 l-1 respectively. Furthermore, excystment was suppressed by both stepwise increase and decrease in salinity or DO. Though R. esculentum podocysts could survive extreme environmental conditions such as hypoxia and low salinity, excystment rates were markedly reduced compared to those of other bloom jellyfish species when the DO and salinity levels were returned to normal.