磷酸肌醇激酶FAB1调控拟南芥根毛伸长

FAB1/PIKfyve是介导PI(3,5)P₂ (磷脂酰肌醇3,5-二磷酸)生物合成的磷酸肌醇激酶。在动物和酵母(Saccharomyces cerevisiae)中, PI(3,5)P₂参与调控胞内膜运输, 但在植物中的研究较少。该文通过分析拟南芥(Arabidopsis thaliana) FAB1的T-DNA插入突变体的表型解析PI(3,5)P₂的生物学功能。拟南芥FAB1基因家族包含FAB1A、FAB1B、FAB1C和FAB1D四个基因。研究发现, fab1a/b呈现雄配子体致死的表型。利用遗传杂交获得fab1b/c/d三突变体, 发现FAB1B、FAB1C和FAB1D功能缺失导致根毛相比野生型变短, 经FAB1特异性抑制剂YM201636处理后的野生型中也观察到相似的短根毛表型。此外, fab1b/c/d三突变体中DR5转录水平降低。同时, 外源施加生长素类似物2,4-D和NAA能部分恢复fab1b/c/d植株短根毛的表型, 但fab1b/c/d突变体对生长素转运抑制剂(1-NOA和TIBA)的敏感性与野生型相似。此外, FAB1B/C/D功能缺失使根毛中ROS的含量减少且影响肌动蛋白的表达。上述结果表明, FAB1B/C/D通过调控生长素分布、ROS含量和肌动蛋白的表达影响拟南芥根毛伸长。     

Engineering lysine‐rich caleosins as carrier proteins to render biotin as a hapten on artificial oil bodies for antibody production

It has been demonstrated that caleosin alone is sufficient to stabilize artificial oil bodies. A series of recombinant caleosins, mutated with 3, 5, 8, 11, 13, 15, and 17 extra Lys residues and over‐expressed in Escherichia coli, were used as carrier proteins to render biotin as a hapten on the surface of artificial oil bodies for antibody production. Biotinylation levels of the recombinant caleosins were step‐wisely elevated as the number of extra Lys residues increased, and the biotinylated Lys residues were identified by mass spectrometric analysis. Polyclonal antibodies against biotin were successfully generated in rats injected with artificial oil bodies constituted with each of the biotinylated caleosins. Moreover, those generated via the biotinylated caleosins with eight or more extra Lys residues no longer recognized caleosin. It appears that engineered Lys‐rich caleosins are suitable carrier proteins for the production of antibodies against small molecules. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011     

Correlation between bilayer destabilization and activity enhancement by diacylglycerols in reconstituted Ca-ATPase vesicles

Using the reconstituted Ca-ATPase vesicles as a model system, we demonstrated that the presence of 1,2-dioleoyl-sn-glycerol (diolein) in the membrane introduces a pronounced enhancement in the Ca-transport function of Ca-ATPase, while the 1,2-dipalmitoyl-sn-glycerol (dipalmitin) does not. We also found by both 31P NMR and freeze-fraction electron microscopy that diolein destabilized lipid bilayers to a greater extent than did dipalmitin. We conclude that the tendency of diacylglycerols to destabilize the phospholipid bilayer is related to their capacity to enhance the activity of the membrane calcium pump.     

Repeated pre-training sleep restriction in adolescent rats impaired spatial performance

Sleep and Biological Rhythms - Chronic sleep deprivation (SD) is an overwhelming problem in young students. Firstly, we investigated whether different levels of pre-training SD had effects on...