High-continuity genome assembly of the jellyfish Chrysaora quinquecirrha.

The Atlantic sea nettle ( Chrysaora quinquecirrha) has an important evolutionary position due to its high ecological value. However, due to limited sequencing technologies and complex jellyfish genomic sequences, the current C. quinquecirrha genome assembly is highly fragmented. Here, we used the most advanced high-throughput chromosome conformation capture (Hi-C) technology to obtain high-coverage sequencing data of the C. quinquecirrha genome. We then anchored these data to the previously published contig-level assembly to improve the genome. Finally, a high-continuity genome sequence of C. quinquecirrha was successfully assembled, which contained 1 882 scaffolds with a N50 length of 3.83 Mb. The N50 length of the genome assembly was 5.23 times longer than the previously released one, and additional analysis revealed that it had a high degree of genomic continuity and accuracy. Acquisition of the high-continuity genome sequence of C. quinquecirrha not only provides a basis for the study of jellyfish evolution through comparative genomics but also provides an important resource for studies on jellyfish growth and development.

[Effect of Extracellular Polymeric Substance (EPS) on the Adsorption of Perfluorooctane Sulfonate (PFOS) onto Activated Sludge].

The adsorption of PFOS by activated sludge and EPS-removed sludge was conducted to investigate the adsorption mechanism of activated sludge and the effect of EPS on this adsorption process. The experimental results indicated that the adsorption process of PFOS onto activated sludge and EPS-removed sludge fitted the pseudo-second-order model, with equilibrium absorption capacities (qe) of 0.46 mg·g-1 and 0.38 mg·g-1, respectively. The sorption isotherm accorded well with the Freundlich, Langmuir, and Temkin models. Chemisorption played an important role in the adsorption of PFOS on the activated sludge. Ca2+ and Cu2+ contributed to PFOS adsorption on the activated sludge through an ion-bridging effect. Adsorption efficiency was better on the normal activated sludge compared to the EPS-removed sludge. FTIR and XPS were used to analyze the variations of functional groups before and after sorption. The results showed that the amount of functional groups such as hydroxyl, carboxyl, and amidogen on EPS-removed sludge was lower; however, these functional groups were found to have participated in the PFOS adsorption process. It is concluded that carboxyl and amidogen contained in protein of EPS provided reaction sites for PFOS adsorption, thus EPS components played a vital role in PFOS adsorption on the activated sludge.

Effect of chlorogenic acid on melanogenesis of B16 melanoma cells.

Chlorogenic acid (CGA), the ester formed between caffeic acid and l-quinic acid, is a widespread phenolic compound. It is part of the human diet, found in foods such as coffee, apples, pears, etc. CGA is also was widely used in cosmetics, but the effects of CGA on melanogenesis are unknown. In this study, we analyzed the effects of CGA on cell proliferation, melanin content and tyrosinase of B16 murine melanoma cells. Additionally, the enzymatic reactions of CGA in B16 melanoma cells lytic solution were detected by UV spectrophotometry. Results showed CGA at 30 and 60 µM significantly suppresses cell proliferation. 8-MOP at 100 µM significantly promotes cell proliferation, but CGA can counter this. Incubated for 24 h, CGA (500 µM) improves melanogenesis while suppressing tyrosinase activity in B16 melanoma cells or 8-methoxypsoralen (8-MOP) co-incubated B16 melanoma cells. After 12 h, B16 melanoma cell treatment with CGA leads to an increase in melanin accumulation, however, after 48 h there is a decrease in melanin production which correlates broadly with a decrease in tyrosinase activity. CGA incubated with lytic solution 24 h turned brown at 37 °C. The formation of new products (with a maximum absorption at 295 nm) is associated with reduction of CGA (maximum absorption at 326 nm). Therefore, CGA has its two sidesroles in melanogenesis of B16 melanoma cells. CGA is a likely a substrate of melanin, but the metabolic product(s) of CGA may suppress melanogenesis in B16 melanoma cells by inhibiting tyrosinase activity.