Myrmecia incisa is a green coccoid freshwater microalgae, which is rich in arachidonic acid （ArA, C20： 4ω-6, △5, 8, 11, 14）, a long chain polyunsaturated fatty acid （PUFA）, especially under nitrogen starvation ...Myrmecia incisa is a green coccoid freshwater microalgae, which is rich in arachidonic acid （ArA, C20： 4ω-6, △5, 8, 11, 14）, a long chain polyunsaturated fatty acid （PUFA）, especially under nitrogen starvation stress. A cDNA library of M. incisa was constructed with λ. phage vectors and a 545 nt expressed sequence tag （EST） was screened from this library as a putative elongase gene due to its 56% and 49% identity to Marchantia polymorpha L. and Ostreococcus tauri Courties et Chretiennot-Dinet, respectively. Based upon this EST sequence, an elongase gene designated MiFAE was isolated from M. incisa via 5＇/3＇ rapid amplification of cDNA ends （RACE）. The cDNA sequence was 1 331 bp long and included a 33 bp 5＇-untranslated region （UTR） and a 431 bp 3＇-UTR with a typical poly-A tail. The 867 bp ORF encoded a predicted protein of 288 amino acids. This protein was characterized by a conserved histidine-rich box and a MYxYY motif that was present in other members of the elongase family. The genomic DNA sequence of MiFAE was found to be interrupted by three introns with splicing sites of Introns I （81 bp）, II （81 bp）, and III （67 bp） that conformed to the GT-AG rule. Quantitative real-time PCR showed that the transcription level of MiFAE in this microalga under nitrogen starvation was higher than that under normal condition. Prior to the ArA content accumulation, the transcription of MiFAE was enhanced, suggesting that it was possibly responsible for the ArA accumulation in this microalga cultured under nitrogen starvation conditions.展开更多
Solar evaporation has emerged as an attractive technology to produce freshwater by utilizing renewable solar energy.However,it remains a huge challenge to develop efficient solar steam generators with good flexibility...Solar evaporation has emerged as an attractive technology to produce freshwater by utilizing renewable solar energy.However,it remains a huge challenge to develop efficient solar steam generators with good flexibility,low cost and remarkable salt resistance.Herein,we prepare flexible,robust solar membranes by filtration of porous carbon and commercial paper pulp fiber.The porous carbon with well-defined structures is prepared through controlled carbonization of biomass/waste plastics by eutectic salts.We prove the synergistic effect of porous carbon and paper pulp fiber in boosting solar evaporation performance.Firstly,the porous carbon displays a high light absorption,while the paper pulp fiber with good hydrophilicity effectively promotes the transport of water.Secondly,the combination between porous carbon and paper pulp fiber reduces the water vaporization enthalpy by 20%,which is important to significantly improve the evaporation performance.As a proof of concept,the porous carbon/paper pulp fiber membrane possesses a high evaporation rate of 1.8 kg m^(-2)h^(-1)under 1 kW m^(-2)irradiation.Thirdly,the good flexibility and mechanical property of paper pulp fiber enable the solar membrane to work well under extreme conditions(e.g.,after 20 cycles of folding/stretching/recovery).Lastly,due to the super-hydrophilicity and superwetting,the hybrid membrane exhibits the exceptional salt resistance and long-term stability in continuous seawater desalination,e.g.,for 50 h.Importantly,a large-scale solar desalination device for outdoor experiments is developed to produce freshwater.Consequently,this work provides a new insight into developing advanced flexible solar evaporators with superb performance in seawater desalination.展开更多
基金Supported by the National Natural Science Foundation of China (No.30972243)the Creative Project of the Shanghai Municipal Education Committee (No.09ZZ167)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,the Key Discipline Project of the Shanghai Municipal Education Committee (No.J50701)the Excellent Thesis Grant from Shanghai Ocean University
文摘Myrmecia incisa is a green coccoid freshwater microalgae, which is rich in arachidonic acid （ArA, C20： 4ω-6, △5, 8, 11, 14）, a long chain polyunsaturated fatty acid （PUFA）, especially under nitrogen starvation stress. A cDNA library of M. incisa was constructed with λ. phage vectors and a 545 nt expressed sequence tag （EST） was screened from this library as a putative elongase gene due to its 56% and 49% identity to Marchantia polymorpha L. and Ostreococcus tauri Courties et Chretiennot-Dinet, respectively. Based upon this EST sequence, an elongase gene designated MiFAE was isolated from M. incisa via 5＇/3＇ rapid amplification of cDNA ends （RACE）. The cDNA sequence was 1 331 bp long and included a 33 bp 5＇-untranslated region （UTR） and a 431 bp 3＇-UTR with a typical poly-A tail. The 867 bp ORF encoded a predicted protein of 288 amino acids. This protein was characterized by a conserved histidine-rich box and a MYxYY motif that was present in other members of the elongase family. The genomic DNA sequence of MiFAE was found to be interrupted by three introns with splicing sites of Introns I （81 bp）, II （81 bp）, and III （67 bp） that conformed to the GT-AG rule. Quantitative real-time PCR showed that the transcription level of MiFAE in this microalga under nitrogen starvation was higher than that under normal condition. Prior to the ArA content accumulation, the transcription of MiFAE was enhanced, suggesting that it was possibly responsible for the ArA accumulation in this microalga cultured under nitrogen starvation conditions.
基金financially supported by the National Natural Science Foundation of China(51903099 and 51991353)Huazhong University of Science and Technology(3004013134 and 2021XXJS036)+1 种基金the 100 Talents Program of the Hubei Provincial Governmentthe Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003).
文摘Solar evaporation has emerged as an attractive technology to produce freshwater by utilizing renewable solar energy.However,it remains a huge challenge to develop efficient solar steam generators with good flexibility,low cost and remarkable salt resistance.Herein,we prepare flexible,robust solar membranes by filtration of porous carbon and commercial paper pulp fiber.The porous carbon with well-defined structures is prepared through controlled carbonization of biomass/waste plastics by eutectic salts.We prove the synergistic effect of porous carbon and paper pulp fiber in boosting solar evaporation performance.Firstly,the porous carbon displays a high light absorption,while the paper pulp fiber with good hydrophilicity effectively promotes the transport of water.Secondly,the combination between porous carbon and paper pulp fiber reduces the water vaporization enthalpy by 20%,which is important to significantly improve the evaporation performance.As a proof of concept,the porous carbon/paper pulp fiber membrane possesses a high evaporation rate of 1.8 kg m^(-2)h^(-1)under 1 kW m^(-2)irradiation.Thirdly,the good flexibility and mechanical property of paper pulp fiber enable the solar membrane to work well under extreme conditions(e.g.,after 20 cycles of folding/stretching/recovery).Lastly,due to the super-hydrophilicity and superwetting,the hybrid membrane exhibits the exceptional salt resistance and long-term stability in continuous seawater desalination,e.g.,for 50 h.Importantly,a large-scale solar desalination device for outdoor experiments is developed to produce freshwater.Consequently,this work provides a new insight into developing advanced flexible solar evaporators with superb performance in seawater desalination.
