Environmental forcing on jellyfish communities in a small temperate estuary

Benthic ecosystem determines jellyfish blooms by controlling the polyp colony development

The harmful irregular jellyfish blooms in recent years are difficult to be deciphered by macro hydrographic condition changes. To fundamentally explain the dynamic of jellyfish populations, we shifted the focus to the polyp stage of jellyfish life cycle and local benthic ecosystems. We monitored the population dynamics of Aurelia coerulea polyps in Jiaozhou Bay and other benthic biofouling species in situ to explore the adaptive mechanism of polyps and interspecific interactions in the benthic microhabitat. Our results showed that as temperature increased, the polyps multiplied on the bare substrate, however, other benthic fouling organisms simultaneously invaded the polyp colony according to their different colonisation methods and physiological characteristics. In addition, the polyps were extremely tolerant to food scarcity in the natural environment at low temperatures. Our study indicated that it is necessary to consider the local benthic ecosystem and implement ecosystem-based management strategies to predict and manage problematic jellyfish blooms.

Macroscale abundance patterns of hydromedusae in the temperate Southwestern Atlantic (27°-56° S)

Gelatinous organisms are crucial components of marine ecosystems and some species imply social and economic consequences. However, certain geographic areas, such as the temperate Southwestern Atlantic (SWA, 27° - 56° S), remain understudied in terms of jellyfish ecological data. We analyzed 3,727 plankton samples collected along ~6.7 million km2 over a 31-year period (1983-2014) to determine the occurrence, abundance, and diversity patterns of hydromedusae in the SWA. Analyses were made at both community and species levels. Two abundance hot spots of hydromedusae were identified, where values up to 2,480 ind. m-3 were recorded between 2003 and 2014. Liriope tetraphylla and Obelia spp. were the main responsible for recurrent peaks. Diversity indexes were in the range of those published for temperate areas worldwide, and some coastal zones showed values that can be considered moderate to high for a temperate neritic region. The community analysis yielded 10 groups following previously determined biogeographic schemes throughout the study area. This work enhances the knowledge of hydromedusae in the SWA and provides essential information about the current global warming context and the gelatinous zooplankton data necessity.

A novel granulin homologue isolated from the jellyfish Cyanea capillata promotes proliferation and migration of human umbilical vein endothelial cells through the ERK1/2-signaling pathway

Jellyfish grow rapidly and have a strong regenerative ability, indicating that they may express high levels of growth factors. Therefore, the aim of this research was to isolate the growth-promoting components from the jellyfish Cyanea capillata (C. capillata) and to further explore the underlying mechanisms. In this study, we first isolated and identified a novel polypeptide from C. capillata tentacles using size-exclusion chromatography followed by reverse-phase HPLC. This peptide, consisting of 58 amino acids (MW 5782.9 Da), belonged to the granulin (GRN) family of growth factors; thus, we named it Cyanea capillata granulin-1 (CcGRN-1). Second, using CCK-8 assay and flow cytometry, we verified that CcGRN-1 at the 0.5 μg/ml concentration could promote cell proliferation and increase the expression of cell-cycle proteins (CyclinB1 and CyclinD1). Third, signaling pathways studies showed that CcGRN-1 could activate the PI3K/Akt- and ERK1/2 MAPK-signaling pathways but not the JNK MAPK- or NF-κB-signaling pathways. Subsequently, we further confirmed that the CcGRN-1-induced cell proliferation and migration were associated only with the ERK1/2 MAPK-signaling pathway. Considering all of these factors, CcGRN-1, as the first jellyfish-derived GRN homologue, possesses growth-promoting properties and may be a candidate for novel therapeutics to promote human wound healing in unfavorable conditions.

Tentacle extract from the jellyfish Cyanea capillata increases proliferation and migration of human umbilical vein endothelial cells through the ERK1/2 signaling pathway

Wound healing is a complex biological process, and current research finds that jellyfish have a great capacity for promoting growth and healing. However, the underlying mechanisms remain unclear. Thus, this study was conducted to investigate the molecular mechanisms and effects of a tentacle extract (TE) from the jellyfish Cyanea capillata (C. capillata) on cell proliferation and migration in human umbilical vein endothelial cells (HUVECs). First, our results showed that TE at the concentration of 1 μg/ml could promote cell proliferation over various durations, induce a transition of the cells from the G1-phase to the S/G2-phase of the cell cycle, and increase the expression of cell cycle proteins (CyclinB1 and CyclinD1). Second, we found that TE could activate the PI3K/Akt, ERK1/2 and JNK MAPK signaling pathways but not the NF-κB signaling pathway or the apoptosis signaling cascade. Finally, we demonstrated that the TE-induced expression of cell cycle proteins was decreased by ERK1/2 inhibitor PD98059 but not by PI3K inhibitor LY294002 or JNK inhibitor SP600125. Similarly, the TE-enhanced migration ability of HUVECs was also markedly attenuated by PD98059. Taken together, our findings indicate that TE-induced proliferation and migration in HUVECs mainly occurred through the ERK1/2 MAPK signaling pathway. These results are instructively important for further research on the isolation and purification of growth-promoting factors from C. capillata and are hopeful as a means to improve human wound repair in unfavorable conditions.

Hydrographic processes driven by seasonal monsoon system affect siphonophore assemblages in tropical-subtropical waters (western North Pacific Ocean)

This work is a part of the Taiwan Cooperative Oceanic Fisheries Investigation, the first large scale hydrographic and plankton survey around Taiwan (21-26°N, 119-123°E). The present study examined the influence of hydrodynamic and biological variables driven by monsoon system on the siphonophore assemblages through an annual cycle in 2004. Calycophorans, namely Chelophyes appendiculata, Diphyes chamissonis, Lensia subtiloides, Bassia bassensis, and Muggiaea atlantica, were the most dominant siphonophore species. Maximum abundance of these dominant species generally occurred during the warm period (May and August), while M. atlantica had a significantly peak abundance in February. Although no apparently temporal difference in siphonophore abundance was observed in the study, siphonophore assemblage was more diverse in August than in other sampling times. Result of a cluster analysis indicated that assemblage structure of siphonophores in the waters around Taiwan varied at temporal and spatial scales during the sampling period. The intrusions of the Kuroshio Branch Current and China Coastal Current to the study area play an important role on the transportation of siphonophores. Also, the distribution of siphonophore assemblage was closely related to the hydrographic characteristics, with temperature, chlorophyll a concentration, and zooplankton abundance being the major environmental factors affecting the spatio-temporal variability of siphonophores. This study contributes substantially to the new knowledge of the siphonophore assemblage in the tropical-temperate waters of Taiwan.