东北虎豹国家公园试点经验

东北虎豹国家公园体制试点区位于吉林、黑龙江两省交界的老爷岭南部区域,跨吉林、黑龙江两省,与俄罗斯、朝鲜接壤,试点区面积1.46万km2,其中69.4％位于吉林省,30.6％位于黑龙江省(梁兵宽等,2020).试点区的主要保护对象为温带针阔叶混交林生态系统,以及野生东北虎(Panthera tigris altaica)...     

Advances in 3D cell culture for liver preclinical studies

The 3D cell culture model is an indispensable tool in the study of liver biology in the field of health and disease and the development of clinically relevant p...     

细胞外Mn^2＋对内向整流钾通道（IRK1）的阻断作用

目的和方法：采用双微电极电压钳（ＴＥＶ）法研究细胞外Ｍｎ＾２＋对非洲爪蟾卵母细胞表达的内向整流钾通道（ＩＲＫ１）的阻断作用。结果：细胞外Ｍｎ＾２＋浓度分别为１、１．２５、２．５、５、１０和２０ｍｍｏｌ／Ｌ,Ｋ＾＋浓度为９０ｍｍｏｌ／Ｌ,可见Ｍｎ＾２＋对ＩＲＫ１的瞬间电流（旋加电压后２ｍｓ）具有Ｍｎ＾２＋浓度依赖性和电压依赖性阻断作用;细胞外加Ｍｎ＾２＋浓度较高时强;细胞外Ｋ＾＋浓度为９０ｍｍｏｌ／     

酿酒酵母表面展示鲑鱼降钙素多肽的研究

目的:实现酿酒酵母表面展示鲑鱼降钙素.方法:人工合成鲑鱼降钙素(Salmon cacitonin,sCT)编码基因,克隆到表面展示载体M-pYD1上.用NocⅠ酶切重组质粒M-pYD1-sCT和空白质粒M-pYD1,回收sCT和V5表达框片段后分别以LiAC法转化酿酒酵母EBY100菌株,分别得到重组酵母yAGA2-sCT和yAGA2-V5.两种重组酵母分别经半乳糖诱导表达后,采用FITC荧光标记酵母表面展示的sCT和V5多肽,分别用荧光显微镜和流式细胞仪进行定性和定量分析.结果:诱导12h后,荧光显微镜下清晰观测到了工程菌表面有重组sCT,流式细胞分析结果表明10000个细胞中65.2%的yAGA2-sCT菌株表达了外源sCT,52.4%的yAGA2-V5菌株表达V5.结论:利用酿酒酵母表面展示鲑鱼降钙素多肽获得了成功,为口服型鲑鱼降钙素的研发奠定了基础.     

转基因定量检测用质粒分子标准物质研究进展

近10年来,应用于转基因植物产品定量检测的质粒分子标准物质凭借其易于富集,快捷高效等优点,成为各国检测机构的研究热点。对国内外转基因植物核酸定量检测用的质粒分子标准物质研究进展进行总结和评述,并且对该类标准物质在研制过程中的问题进行分析,同时展望了该类标准物质的发展与应用。     

Water permeability of plant cuticular membranes: the effects of humidity and temperature on the permeability of non-isolated cuticles of onion bulb scales

Abstract. Water permeability of cuticular membranes (CM) from the inner bulb scales of Allium cepa has been investigated. CM have a thickness ranging from 0.6 to 1.3 μm. They are composed of a thin (120–200 nm) lamellated cuticle proper and a thicker (300–900 nm) cuticular layer. Permeability coefficients for diffusion of water across these thin membranes are very low (4 × lO⁻¹⁰ms⁻¹⁰). There was no difference in permeability of CM from successive scales of the same onion. Extraction of soluble cuticular lipids (SCL) with chloroform increased permeability by a factor of 1350 to 2050. Preliminary data indicate that only 1 μg cm⁻¹⁰ of SCL are removed by this treatment, hydrocarbons being the main (75%) consistuent. Permeability coefficients of cuticular transpiration were little affected by relative humidity, showing that transport is limited by a hydrophobic barrier that lacks dipoles. However, following extraction, permeability of the membranes depended strongly on humidity due to the presence of polar functional groups in the polymer matrix. Soluble cuticular lipids undergo a phase transition around 47°C. Temperatures higher than that irreversibly increased water permeability.