The effect of a secretion-enhanced heavy chain on improving intein-based dual-vector co-delivery of a full-length factor VIII gene

Treatment of hemophilia A by gene therapy is adversely affected by inefficient FVIII secretion and the large FVIII gene, which is difficult to package in the promising adeno-associated virus (AAV) vectors. Inhibited secretion of FVIII is caused mainly by inefficient secretion of its heavy chain. Previously, we have employed a protein splicing-based dual-vector to co-transfer a B-domain-deleted FVIII (BDD-FVIII) gene, suggesting that the light chain, covalently ligated to a co-expressed heavy chain can improve the secretion of spliced BDD-FVIII. However, its level of secretion was affected by inefficient secretion the heavy chain. Here, we studied the effect of a mutant heavy chain with L303E/F309S substitutions, which enhance FVIII secretion on the heavy chain itself and spliced FVIII when using a protein splicing-based split-delivery of a full-length FVIII gene. Eukaryotic vectors expressing Ssp DnaB intein-fused mutant heavy and light chains were transiently co-transfected into cultured COS-7 cells. A spliced FVIII protein was seen in co-transfected cells by Western blot analysis. The heavy chain was secreted by cells transfected with the mutant heavy chain gene alone at (39±11) ng/mL and this secretion increased to (123±13) ng/mL when cells were co-transfected with the light chain gene, which was greater than the secretion of wild-type heavy chain. The amount of spliced FVIII in the culture supernatant of co-transfected cells was (86±14) ng/mL, with an activity of (0.61±0.08) IU/mL, which was greater than that of wild-type FVIII co-transfected cells. Spliced FVIII and bioactivity were also detected in the combined culture supernatant of cells individually transfected with mutant heavy and light chain gene at a higher level than that of combined wild-type heavy and light chain transfections. This suggested that the heavy chain with improved secretion markedly increased the efficacy of protein splicing-based split delivery of the full-length FVIII gene using a dual-vector. These results encourage the transfer of this technology to an animal model using a dual-AAV vector.     

Analysis for retrieval and validation results of FY-3 Total Ozone Unit (TOU)

Retrieval experiment was made for global total column ozone using the first year measurements of Total Ozone Unit (TOU) on board the second generation polar orbiting meteorological satellite of China, FY-3/A. The retrieval results were analyzed and validated by comparison with AURA/OMI, Meteop/GOME-2 global ozone products and ground-based ozone measurement data. The qualititative comparisons over the globe especially over Antarctica and the Tibetan Plateau show that the spatial and temporal distribution characteristics are consistent with OMI and GOME-2 products. The quantitative comparisons with ground-based measurements and AURA/OMI ozone product were made over 74 stations, the TOU total ozone retrieval has a 3% rms relative error compared with AURA/OMI ozone product and 4.2% rms relative error with ground-based measurements. The maximum difference between satellite retrieval and ground-based measurements was found in the Antarctica ozone hole. The TOU global ozone product is operational and distributed to all users.     

FY-3 satellite Ultraviolet Total Ozone Unit

FY-3 satellites are Chinese second-generation polar orbit meteorological satellite series. Ultraviolet Total Ozone Unit (TOU) is one of the main payloads on FY-3 satellite and the first instrument for daily global coverage of total ozone monitoring in China. The main purpose of TOU is to measure the Earth backscatter ultraviolet radiation for retrieving daily global map of atmospheric ozone. TOU will provide the important parameters for environmental monitoring, climate forecasting and global climate changi...     

食品添加剂乙基麦芽酚的合成工艺研究

以α-呋喃丙醇为原料,经电解、酸化、氧化、水解4步合成乙基麦芽酚。利用傅里叶变换红外光谱仪(FT-IR)分析鉴定合成中间体结构,其红外吸收数据与文献一致。考察了通电量、电解质、酸化条件、氧化时间、水解时间、水解温度对乙基麦芽酚收率的影响,得到适宜的反应条件为通电量2～25F/mol,NaBr作电解质,室温下酸化,乙醇作回流溶剂,氧化时间3h,水解时间3～4h,水解温度100℃。采用分光光度法测定乙基麦芽酚收率,最高可达62.04%。     

Vertical ozone profiles deduced from measurements of SBUS on FY-3 satellite

The FY-3 satellite is a second-generation Chinese polar-orbit meteorological satellite.The Solar Backscatter Ultraviolet Sounder (SBUS),one of the main payloads on the FY-3 satellite,is the first Chinese ozone-monitoring instrument on a meteorological satellite.As part of the in-orbit validation of FY-3,we carried out a retrieval trial using measurements from SBUS during the period of 17-30 July,2008,and compared those data with measurements and retrieved profiles from the National Oceanic and Atmospheric A...     

Monitoring of the 2011 spring low ozone events in the Arctic region

Data from FY-3B SBUS and NOAA SBUV/2 were used to monitor ozone levels in the Arctic region from March 1 to April 5, 2011. Results revealed a significant ozone depletion in the area, with total ozone levels between 200–250 DU. The ozone levels recorded were 100–200 DU below normal, and in some parts the levels were as low as 200 DU, indicating a mini ozone-hole. During the sampling period, the ozone depletion area underwent identifiable expansion and detraction, a rotation around the North Pole from the west to the east, and a longitudinal movement from the Pole, spreading to the mid latitudes. The effects of these rare low ozone events were not only felt in the Arctic, but also extended to densely populated areas between Europe and the middle of Russia. In this region, rapidly increasing levels of ultraviolet radiation were detected at the Earth’s surface. Given the significant risk that this poses to both the environment and people’s health, this occurrence has significant global implications.     

钛硅分子筛催化合成乙基麦芽酚的工艺研究

提出了以α-呋喃丙醇为原料,TS-1作催化剂,H2O2作氧化剂制备乙基麦芽酚中间体的新方法。中间体经苷化、氧化、水解步骤合成乙基麦芽酚。考察了溶剂、催化剂用量、氧化温度、氧化时间、苷化条件、pH值对乙基麦芽酚收率的影响,得到适宜的反应条件为:氧化温度40℃,氧化时间12h,苷化温度75℃,pH为8,氧化3h,水解温度100℃,水解时间3h,乙基麦芽酚最高收率可达57.4%。