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Jellyfish blooms have become a hot research topic in recent decades because they pose a serious threat to fisheries, coastal industries, tourism, and the marine ecosystem. The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage, where asexual reproduction and strobilation of the polyps directly affect the abundance of ephyra and subsequently medusa abundance. The dynamics of polyps are affected by both environmental and biological factors, and predation by natural predators is one of the most important biological factors. Nemopilema nomurai, Aurelia coerulea, and Rhopilema esculentum are three scyphozoan species that are commonly found in Chinese coastal waters, and previous studies reported that the survivorship of polyps differs among the three species when they are exposed to the same benthic community. To identify potential natural predators of polyps of these three species in Chinese coastal waters and to determine whether the predation rates on polyps of the three species differ, we collected 39 species of macrozoobenthos from the Bohai Sea, Yellow Sea, and East China Sea from May 2014 to June 2016 and conducted predation tests and predation rate measurements. We found that the nudibranchs Pleurobranchaea novaezealandiae, Okenia plana, and Chromodoris tinctoria and the sea anemones Paracalliactis sinica, Calliactis japonica, Anthopleura incerta, and Anthopleura midori could prey on the polyps of all three scyphozoan species. The predation rates increased with the body length of the predators. The predations rates were also related to the polyp species, although the different predators showed no consistent preference for a particular species of polyp. Our results indicate that introducing predators to locations inhabited by polyps might be a way to control the benthic polyp populations and prevent subsequent jellyfish blooms.

Jellyfish envenomation is a world-wide health problem, which often seriously affect the fishery and bathing activities. To date, few individual jellyfish venoms proteins have been thoroughly characterized yet. In this work, four species of scyphozoan jellyfish (Nemopilema nomurai, Cyanea nozakii, Aurellia aurita and Rhopilema esculentum) are compared according to their, cytotoxicity, hemolytic potency, brine shrimp toxicity and protein components. Jellyfish venoms showed higher cytotoxicity in H9C2 heart myoblast than in C2C12 skeletal myoblast, with the exception of C. nozakii venom. This result suggests that the selective cytotoxic effects may be possibly related to their in vivo effects of cardiac tissue dysfunction. On the other hand, hemolytic activity could be also observed from all tested jellyfish venoms. N. nomurai jellyfish venom displaying the greatest hemolytic activity. As an alternative method of evaluating the toxicities of jellyfish venoms, the toxicity on brine shrimp was examined with the four jellyfish venoms. From this, the venom of N. nomurai showed higher toxicity against brine shrimp than the other jellyfish venoms, which is consistent with the results of cytotoxicity assay as well as hemolysis assay of the present study. SDS-PAGE analysis of four jellyfish venoms showed the similar pattern with molecular weight of around 40 kDa, and appeared to be the major protein components. These results provided that N. nomurai jellyfish venom was potently toxic than other scyphozoan jellyfish venoms and may explain to some extent the deleterious effects associated with human envenoming.

R. esculentum is a popular seafood in Asian countries and an economic marine fishery resource in China. However, the high-resolution genetic map and growth-related molecular markers still lack, hindering the process of the genetic breeding of R. esculentum. Therefore, we firstly used the 2b-RAD method to sequence 152 R. esculentum specimens, identified 9100 single nucleotide polymorphism (SNP) markers and constructed a high-resolution genetic map with a marker interval of 0.58 cM, covering 98.68% of the genome. Then, we separately detected four and three quantitative trait loci (QTLs) associated with umbrella diameter and body weight based on the linkage map, which is located on linkage group (LG) 4, 13, 14 and 15. Finally, 27 genes were found both associated with umbrella diameter and body weight of R. esculentum by genome-wide association study (GWAS), in which one gene named RE13670 containing calcium-binding EGF-like domain may play an important role in controlling the growth. This study will be beneficial for underlying the growth mechanism of R. esculentum and also provide background knowledge for guiding its genetic breeding.

Jellyfish blooms occur worldwide and have resulted in serious problems in tourism, fisheries, coastal industries, and the marine ecosystem. The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage. Success of asexual reproduction of the polyps determines directly the number of medusae; thus, the polyp stage is the key to understanding the population dynamics of medusae. Nemopilema nomurai, Aurelia coerulea, and Rhopilema esculentum are three scyphozoan jellyfish commonly inhabit in Chinese coastal waters. Polyps of A. coerulea are easily visible, while those of N. nomurai and R. esculentum remain yet to be found in the wild. However, distribution of the medusa indicates that the polyps of all three species may occur together. To evaluate the distribution pattern of polyps of the three species and explore intraguild predation by the polyps, we conducted a laboratory experiment that considered the attachment sequence and size relationship of calyx diameter of the polyps. We found that the polyps of A. coerulea preyed on polyps of the other two species in all treatments, except when polyps of R. esculentum were bigger than those of A. coerulea. The polyps of R. esculentum preyed on the polyps of N. nomurai only when polyps of R. esculentum attached first and were bigger than those of N. nomurai. Colonies of N. nomurai polyps were rarely found in the places inhabited by A. coerulea polyps. In addition, A. coerulea polyps are known to inhabit at depths of less than 20 m in coastal sea, thus, we speculate that N. tnomurai polyp colonies might occur at depths of more than 20 m. Therefore, our finding that polyps of A. coerulea aggressively preyed on polyps of other species may help understand other such systems of jellyfish bloom in the world.

Seafood traceability is an important means of ensuring the quality of local seafood. Jellyfish are an important edible resource with a large yield on a global scale. Different species of pickled jellyfish, a traditional Chinese food, cannot be differentiated solely from the appearance of the product due to its special processing methods. In this paper, two species of jellyfish, R. esculentum and S. meleagris, were identified by PCR-RFLP technique. The genetic identification of the jellyfish R. esculentum and S. meleagris was based on PCR amplification of a common 651 bp fragment of the 16S rRNA gene, followed by digestion of four restriction enzymes, Hind III, Hpa I, Xho I and Dra I, respectively. The results showed that the two species of fresh jellyfish could be identified clearly, as could the pickled R. esculentum. To verify this result, PCR-RFLP was applied to authenticate four kinds of commercial pickled jellyfish. The electrophoretogram clearly showed that R. esculentum and S. meleagris were easily and accurately authenticated. This PCR-RFLP system has the potential to become an effective method for identifying the jellyfish products from Liaoning Province of China.

It was found that lipids of scyphoid jellyfishes of the Sea of Japan, Aurelia aurita (Linnaeus, 1758) and Rhopilema esculentum (Kishinouye, 1891) contain, along with the common fatty acids (FAs) that are characteristic of marine organisms, notable concentrations of polyunsaturated fatty acids (PUFAs) with 24 and 26 carbon atoms. The main PUFAs in A. aurita and Rh. esculentum were 20:5(n–3), 22:6(n–3), 24:6(n–3), and 22:5(n–3). In addition, it was found for the first time that Rh. esculentum contains 1.6% C26 PUFAs: C26:7(n–3), C26:6(n–3), and C26:5(n–3). In spite of similar PUFA levels in A. aurita and Rh. esculentum (65.95 and 58.79%, respectively), the ratio of the FA (n–3)/(n–6) families was in A. aurita 7 times higher than in Rh. esculentum. Saturated acids (26.57% in A. aurita and 31.75% in Rh. esculentum) were represented by palmitic and stearic acids. The level of monounsaturated FAs, including C16:1 and C18:1 isomers, was low and did not exceed 10% in both species. The presence of unusual families of PUFAs with 24 and 26 carbon atoms and the difference in the contents of FAs (n–3) and (n–6) in species that live under similar conditions is of great interest.

Cnidarians have large surface areas available for colonization by microbial organisms, which serve a multitude of functions in the environment. However, relatively few studies have been conducted on scyphozoan-associated microbial communities. Blooms of scyphozoan species are common worldwide and can have numerous deleterious consequences on the marine ecosystem. Four scyphozoan species, Aurelia coerulea, Cyanea nozakii, Nemopilema nomurai, and Rhopilema esculentum, form large blooms in Chinese seas. In this study, we analyzed the bacterial communities associated with these four jellyfish based on 16S rRNA gene sequencing. We found that the bacterial communities associated with each scyphozoan species were significantly different from each other and from those of the surrounding seawater. There were no significant differences between the bacterial communities associated with different body parts of the four scyphozoan jellyfish. Core bacteria in various compartments of the four scyphozoan taxa comprised 57 OTUs (Operational Taxonomic Units), dominated by genera Mycoplasma, Vibrio, Ralstonia, Tenacibaculum, Shingomonas and Phyllobacterium. FAPROTAX function prediction revealed that jellyfish could influence microbially mediated biogeochemical cycles, compound degradation and transmit pathogens in regions where they proliferate. Finally, Six genera of potentially pathogenic bacteria associated with the scyphozoans were detected: Vibrio, Mycoplasma, Ralstonia, Tenacibaculum, Nautella, and Acinetobacter. Our study suggests that blooms of these four common scyphozoans may cause jellyfish species-specific impacts on element cycling in marine ecosystems, and serve as vectors of pathogenic bacteria to threaten other marine organisms and human health.

The complete mitochondrial genome of Rhopilema esculentum collected from Jiaozhou Bay, China, was determined by next-generation sequencing. The mitogenome is a circular molecule 15,855 bp in length, including 13 protein-coding genes (Cox 1, Cox2, Atp 8, Atp 6, Cox 3, ND2, ND5, ND 6, ND3, ND4L, ND1,ND4, Cytb), 5 tRNAs (tRNA-Trp, tRNA-Met, tRNA-Leu, tRNA-Ser, tRNA-Gln), 2 rRNA genes (small subunit RNA and large subunit RNA) and 1 putative control region. The phylogenetic tree in the related species showed that R. esculentum is close to Nemopilema nomurai.

A numerical model for jellyfish Rhopilema esculentum stock enhancement is developed for the first time. The model is based on an operational ocean circulation-surface wave coupled forecasting system for the seas off China and adjacent areas and uses a Lagrangian particle-tracking scheme to track the trajectories of released jellyfish. The Jellyfish are modeled as particles with diel vertical migration and are passively drifted by the current and dispersion due to the sub-grid processes. A comparison between the simulation and survey results demonstrate that the model can capture the primary distribution patterns of the released jellyfish. The model results show that the ocean current and indirect wind impact are the main drivers controlling the jellyfish transport. A connectivity matrix between the release sites and fishing grounds indicates the top of the bay is better than the eastern and western coasts for jellyfish fishing. The matrix also shows that only 45% and 27% of the jellyfish released from Wafangdian (WFD) can enter the fishing ground in 2008 and 2010; thus, the site near WFD is not an advisable location for jellyfish release. A Lagrangian probability density function based on a nine-year tracing experiment validates the results and further provides a “climatology” distribution of the released jellyfish. Several experiments are conducted to examine the sensitivity of the model to random walk schemes and to release conditions. The model requires a random walk but is insensitive to the random walk scheme. The experiments with different habitat depths show that if the jellyfish are fixed on the bottom of the water, most of them will be transported to the center, or even out of the bay, by the bottom circulation.

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.

Studies of strobilation of scyphozoan polyp populations in the field are essential for determination of the natural seasonal period of ephyra release and for predicting the size of medusa populations, but they have rarely been conducted. We set up experimental polyp colonies of 3 scyphozoans (Aurelia coerulea, Nemopilema nomurai, Rhopilema esculentum) on settling plates in Jiaozhou Bay, China, and monitored them at 2-7 d intervals for 8 mo (December 2012 to August 2013). Polyps of A. coerulea survived, even proliferating by budding during the entire period, while those of N. nomurai and R. esculentum experienced high mortality and died out after strobilation. Strobilation in all 3 species occurred from late winter to early summer, but the exact timing, duration, frequency, strobilation percentage, and disc numbers strobila(-1) differed by species. A. coerulea started strobilation earliest, on 25 February (temperature: 3.9 degrees C), and persisted for 105 d until 9 June (18.1 degrees C). N. nomurai strobilated from 28 March to 9 June (6.4-18.1 degrees C), with some performing a second, less conspicuous strobilation from 6 May to 9 June (12.0-18.1 degrees C). R. esculentum strobilated last, from 15 April to 8 July (9.0-21.5 degrees C). Greater polyp population resilience in A. coerulea over N. nomurai and R. esculentum can be attributed, at least in part, to persistent propagation by budding, which may facilitate the annually recurring medusa blooms of A. coerulea observed in the region. The latter 2 species may give rise to medusa blooms only when their vulnerable polyps have survived well. Due to the later strobilation, R. esculentum ephyrae may be susceptible to competition for food with and predation by post-ephyra stages of A. coerulea and N. nomurai.

The aim of this study was to characterize the effects of different pretreatments on ready-to-eat jellyfish products. Salted jellyfish umbrella edges were used as raw materials. After desalting, samples were blanched under different temperatures for different periods of time. Moisture contents and color characteristics of the pretreated samples were determined, and texture characterized. Masson staining was used to image microstructures, and sensory evaluation was performed. Microbial growth at 37 °C was monitored for samples which underwent the different treatments. Moisture content and whiteness decreased with extended heating, and the higher the temperature, the faster these changes occurred. The moisture content of samples with no heat treatment was 97.89 ± 0.23%, which was nearly 3% higher than that of samples which had undergone heating. The 70 °C heat treatment had a greater effect on the whiteness of jellyfish. Samples exposed to the 60 °C treatment for 1 min had the highest sensory scores, and in conjunction with other results, this temperature was chosen to be the optimal heat treatment. The combination of heating, acid soaking, ultraviolet sterilization and potassium sorbate treatment was shown to prolong the shelf life of jellyfish products effectively.

In this study, single nucleotide polymorphism (SNP), microsatellite (SSR) and differentially expressed genes (DEGs) in the oral parts, gonads, and umbrella parts of the jellyfish Rhopilema esculentum were analyzed by RNA-Seq technology. A total of 76.4 million raw reads and 72.1 million clean reads were generated from deep sequencing. Approximately 119,874 tentative unigenes and 149,239 transcripts were obtained. A total of 1,034,708 SNP markers were detected in the three tissues. For microsatellite mining, 5088 SSRs were identified from the unigene sequences. The most frequent repeat motifs were mononucleotide repeats, which accounted for 61.93%. Transcriptome comparison of the three tissues yielded a total of 8841 DEGs, of which 3560 were up-regulated and 5281 were down-regulated. This study represents the greatest sequencing effort carried out for a jellyfish and provides the first high-throughput transcriptomic resource for jellyfish.

A species of edible Scyphomedusae jellyfish has been used as food by the local people in Ganghwado, Korea since the 1990s. In order to identify this jellyfish, we collected specimens in Ganghwado during September 2013, and compared these specimens with original descriptions made by Kishinouye (1890). Mitochondrial cytochrome oxidase subunit 1 (CO1) sequences of these specimens were compared with those of Rhopilema esculentum retrieved from GenBank. Our specimens were also compared with jellyfish collected in China, previously confirmed as R. esculentum, based on morphological characters and DNA sequences. Using these two methods, the jellyfish specimens caught in Ganghwado were correctly identified as R. esculentum, a species new to Korean waters. This edible jellyfish has been named ‘Gisusik-Yonghaepari’ as Korean name.

BACKGROUND Angiotensin I converting enzyme (ACE) plays an important role in regulating blood pressure in the human body. ACE inhibitory peptides derived from food proteins could exert antihypertensive effects without side effects. Jellyfish (Rhopilema esculentum) is an important fishery resource suitable for production of ACE inhibitory peptides. The objective of this study was to optimize the hydrolysis conditions for production of protein hydrolysate from R. esculentum (RPH) with ACE inhibitory activity, and to isolate and identify the ACE inhibitory peptides from RPH. RESULTS Rhopilema esculentum protein was hydrolyzed with Compound proteinase AQ to produce protein hydrolysate with ACE inhibitory activity, and the hydrolysis conditions were optimized using response surface methodology. The optimum parameters for producing peptides with the highest ACE inhibitory activity were as follows: hydrolysis time 3.90 h, hydrolysis temperature 58 °C, enzyme:substrate ratio 2.8% and pH 7.60. Under these conditions, the ACE inhibitory rate reached 32.21%. In addition, four novel ACE inhibitory peptides were isolated, and their amino acids sequences were identified as Val-Gly-Pro-Tyr, Phe-Thr-Tyr-Val-Pro-Gly, Phe-Thr-Tyr-Val-Pro-Gly-Ala and Phe-Gln-Ala-Val-Trp-Ala-Gly, respectively. The IC50 value of the purified peptides for ACE inhibitory activity was 8.40, 23.42, 21.15 and 19.11 µmol L−1. CONCLUSION These results indicate that the protein hydrolysate prepared from R. esculentum might be a commercial competitive source of ACE inhibitory ingredients to be used in functional foods. © 2015 Society of Chemical Industry

Fifteen polymorphic microsatellite loci were developed and characterized for Rhopilema esculentum using a (GT)(13)-enriched genomic library. The numbers of alleles per locus ranged from 2 to 12, and the observed and expected heterozygosities varied from 0.0417 to 0.8750 and from 0.0086 to 0.7055, respectively. These markers will be helpful for QTL mapping, molecular breeding and investigation of population genetic diversity in R. esculentum.

In the present study, amino acid compositions of two jellyfish gonad samples were determined and the nutritional value was evaluated by the amino acid score method recommend by WHO/FAO and fuzzy recognition method. The two samples were abundant in amino acids. The major amino acids were both glutamic acid, lysine, glycine, aspartic acid and leucine and the contents of these amino acids were 51.47% and 52.52% of the total amino acids, respectively. The essential amino acids were 42.89% and 40.70%, the flavor amino acids were 47.39% and 50.12% and the medicinal amino acids were 66.55% and 66.92% of the total amino acids, respectively. μ (a, μi) values of the two samples were respectively 0.91 and 0.94 and SRC values were respectively 70.89 and 69.96, indicating that the essential amino acids of jellyfish gonad were well-balanced and the nutritional value of jellyfish gonad was high.

Two angiotensin I converting enzyme (ACE) inhibitory peptides were isolated from jellyfish Rhopilema esculentum protein hydrolysates prepared with pepsin and papain. Consecutive purification methods, including ion-exchange chromatography, size-exclusion chromatography and reverse-phase high-performance liquid chromatography, were used for isolation of ACE inhibitory peptides. The amino acid sequence of the peptides was identified as Gln-Pro-Gly-Pro-Thr and Gly-Asp-Ile-Gly-Tyr, respectively, and the IC50 value of the purified peptides for ACE inhibitory activity was 80.67 μM and 32.56 μM. The purified peptides were evaluated for the antihypertensive effect in spontaneously hypertensive rats (SHR) after oral administration. Blood pressure decreased significantly after ingestion of the peptides. The results suggest that peptides derived from jellyfish R. esculentum may be beneficial as antihypertensive compounds in functional food resources.

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space.

Antihypertensive effect of long-term oral administration of jellyfish (Rhopilema esculentum) collagen peptides (JCP) on renovascular hypertension rats (RVHs) was evaluated. The systolic blood pressure and diastolic blood pressure of the RVHs were significantly reduced with administration of JCP (p < 0.05), compared with model control group. However, the arterial blood pressure of normal rats showed no significant changes during long-term oral treatment with high dose JCP (p > 0.05). Furthermore, effect of JCP on angiotensin II (Ang II) concentration of plasma had no significance (p > 0.05), but JCP significantly inhibited the Ang II concentration in RVHs’ kidney (p < 0.05). The kidney should be the target site of JCP.

The inorganic constituents of fresh and cured jellyfish (Rhopilema esculentum), including Zn, Co, Ni, Ba, Mn, Fe, Mg, Ca, Cu, Al, Sr, Mo, Cr, Cd, Pb, Si, V, Ti, Na, K, Li, and Rb, were determined by using inductively coupled plasma optical emission spectrometry. The fresh and cured jellyfish were treated by lyophilization and microwave digestion in turn. Zn, Co, Fe, Mg, Ca, Al, Sr, Cr, Li, and K were used as the added standards to evaluate accuracy. The results show that different parts of jellyfish, such as the umbrella, oral arms, and gonads, contain different amounts of inorganic elements. The relative standard deviation values (RSD) of all elements range from 0.8% to 8.6%. For most of determined elements, RSD values are under 5%. All inorganic elements of the jellyfish can be determined simultaneously after once dissolution. The method is accurate, rapid, and convenient to determine inorganic constituents of the biological sample containing high water content.

Collagen extracted from jellyfish (Rhopilema esculentum) was hydrolyzed with alcalase to prepare the ACE-inhibitory peptide. The optimal hydrolyzing conditions were determined using response surface methodology. The results showed that the optimal conditions were temperature of 52.7 °C, pH of 8.63 and enzyme-to-substrate ratio (E/S) of 3.46%, and the ACE-inhibitory activity of the obtained hydrolysates could reach 81.7%. Jellyfish collagen peptide, UF3-B2, was purified from the hydrolysates using ultrafiltration, ion-exchange chromatography and gel filtration. The IC50 value of UF3-B2 was 43 μg/ml, and the yield accounted for 6.25% of the hydrolysates. The molecular weight distribution of UF3-B2 was from 200 to 600 Da. Amino acid analyses showed that UF3-B2 was rich in Gly, Pro, Glu, Ala, and Asp.

The present work is the first report of the biochemical characterization of the venom from nematocysts of the jellyfish Rhopilema esculentum Kishinouye. The nematocysts were isolated by autolysis and centrifugation and separated by flow cytometry. Four types of nematocysts were identified: mastigophores, euryteles, and atrichous and holotrichous isorhiza. SDS-PAGE and amino acid analyses demonstrated that most of the proteins in the nematocyst extract were between 10 kDa and 40 kDa, and that glutamic acid was the main amino acid. A hemolytic activity assay showed that the activity of the nematocyst venom (RNV) was strongest in Tris-HCl buffer (50 mmol/L, pH 7.8, 5% glycerol, 0.5 mmol/L EDTA, 0.1 mol/L NaCl). The hemolytic activity was related to protein concentration and the HU50 against chicken erythrocytes was 0.91 A mu g/mL.

In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well.

In order to select an optimum extraction method for the target glycoprotein (TGP) from jellyfish (Rhopilema esculentum) oral-arms, a high performance liquid chromatography (HPLC)-assay for the determination of the TGP was developed. Purified target glycoprotein was taken as a standard glycoprotein. The results showed that the calibration curves for peak area plotted against concentration for TGP were linear (r = 0.9984, y = 4.5895x+47.601) over concentrations ranging from 50 to 400 mgL-1. The mean extraction recovery was 97.84% (CV2.60%). The fractions containing TGP were isolated from jellyfish (R. esculentum) oral-arms by four extraction methods: 1) water extraction (WE), 2) phosphate buffer solution (PBS) extraction (PE), 3) ultrasound-assisted water extraction (UA-WE), 4) ultrasound-assisted PBS extraction (UA-PE). The lyophilized extract was dissolved in Milli-Q water and analyzed directly on a short TSK-GEL G4000PWXL (7.8 mm×300 mm) column. Our results indicated that the UA-PE method was the optimum extraction method selected by HPLC.