[Development of resources, technologies and services at the China Zebrafish Resource Center].

With the rapid growth of the Chinese zebrafish community, there is an increasing demand for various types of zebrafish-related resources and technologies. The China Zebrafish Resource Center (CZRC, web: http://zfish.cn) was established at the Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS) in 2012. Till now, CZRC has built the largest zebrafish aquaculture unit in China, organized a resource bank containing more than 1200 zebrafish lines and more than 10 000 frozen sperm samples, among which over 200 mutant and transgenic lines were generated by CZRC. CZRC has established several technical supporting platforms, such as the zebrafish husbandry and health control program of international standard, a high-efficient gene manipulation technology platform, and a stable and efficient sperm cryopreservation technology platform. The main task of CZRC is to provide different types of services to zebrafish investigators in China and worldwide, such as resource services (e.g. zebrafish lines), technical services (e.g. gene knockout) and transgenic services, consultancy services (e.g. zebrafish husbandry and health consultation), and conference services [e.g. holding regular technical training courses and biennale Chinese Zebrafish Principal Investigator Meeting (CZPM)]. After five years' development, CZRC is now recognized as one of the three major resource centers in the global zebrafish community.

Phenolic antioxidants isolated from the flowers of Osmanthus fragrans.

O. fragrans has slightly less antioxidative activity than green tea. Five phenolic compounds, tyrosyl acetate (1), (+)-phillygenin (2), (8E)-ligustroside (3), rutin (4), and verbascoside (5), were isolated from the CHCl3 sub-extract of O. fragrans. The structures were elucidated by interpreting their spectral data. Evaluation of the antioxidative property of the isolated (+)-phillygenin (2), rutin (4), and verbascoside (5) revealed strong DPPH radical scavenging activity, with IC50 values of 19.1, 10.3, and 6.2 µM, respectively. These isolates also exhibited an H2O2 scavenging ability, with IC50 values of 10.5, 23.4, and 13.4 µM, respectively.

Double transgenesis of humanized fat1 and fat2 genes promotes omega-3 polyunsaturated fatty acids synthesis in a zebrafish model.

Omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential nutrients for human health. However, vertebrates, including humans, have lost the abilities to synthesize EPA and DHA de novo, majorly due to the genetic absence of delta-12 desaturase and omega-3 desaturase genes. Fishes, especially those naturally growing marine fish, are major dietary source of EPA and DHA. Because of the severe decline of marine fishery and the decrease in n-3 LC-PUFA content of farmed fishes, it is highly necessary to develop alternative sources of n-3 LC-PUFA. In the present study, we utilized transgenic technology to generate n-3 LC-PUFA-rich fish by using zebrafish as an animal model. Firstly, fat1 was proved to function efficiently in fish culture cells, which showed an effective conversion of n-6 PUFA to n-3 PUFA with the n-6/n-3 ratio that decreased from 7.7 to 1.1. Secondly, expression of fat1 in transgenic zebrafish increased the 20:5n-3 and 22:6n-3 contents to 1.8- and 2.4-fold, respectively. Third, co-expression of fat2, a fish codon-optimized delta-12 desaturase gene, and fat1 in fish culture cell significantly promoted n-3 PUFA synthesis with the decreased n-6/n-3 ratio from 7.7 to 0.7. Finally, co-expression of fat1 and fat2 in double transgenic zebrafish increased the 20:5n-3 and 22:6n-3 contents to 1.7- and 2.8-fold, respectively. Overall, we generated two types of transgenic zebrafish rich in endogenous n-3 LC-PUFA, fat1 transgenic zebrafish and fat1/fat2 double transgenic zebrafish. Our results demonstrate that application of transgenic technology of humanized fat1 and fat2 in farmed fishes can largely improve the n-3 LC-PUFA production.