Unresponsiveness to a foreign antigen can be caused by self-tolerance

In mice, two sets of genes govern the immune response to the synthetic antigen GT. One maps to the major histocompatibility complex and behaves like a typical immune response gene. The second is a background gene encoding a cell surface structure found on B cells. Mice which express, and are therefore tolerant of, one form of this structure do not respond to GT. Thus, tolerance of self generates holes in the T-cell repertoire, partially crippling the immune system.     

Effects of oncogenic mutations in Smoothened and Patched can be reversed by cyclopamine

Basal cell carcinoma, medulloblastoma, rhabdomyosarcoma and other human tumours are associated with mutations that activate the proto-oncogene Smoothened (SMO) or that inactivate the tumour suppressor Patched (PTCH). Smoothened and Patched mediate the cellular response to the Hedgehog (Hh) secreted protein signal, and oncogenic mutations affecting these proteins cause excess activity of the Hh response pathway. Here we show that the plant-derived teratogen cyclopamine, which inhibits the Hh response, is a potential 'mechanism-based' therapeutic agent for treatment of these tumours. We show that cyclopamine or synthetic derivatives with improved potency block activation of the Hh response pathway and abnormal cell growth associated with both types of oncogenic mutation. Our results also indicate that cyclopamine may act by influencing the balance between active and inactive forms of Smoothened.     

Identification and primary genetic analysis of Arabidopsis stomatal mutants in response to multiple stresses

In response to variable environmental conditions, guard cells located in the leaf epidermis can integrate and cope with a multitude of complicated stimuli, thereby making stomata in an appro- priate state. However, many signaling components in guard cell signaling remain elusive. In our laboratory, a tool for non-invasive remote infrared thermal images was used to screen an ethyl methane sulfonate-mutagenized population for Arabidopsis stomatal response mutants under multiple stresses (ABA, H2O2, CO2, etc.). More than forty "hot" or "cold" mutants were isolated (above or below 0.5℃ in con- trast to normal plantlets). Identification and primary genetic analysis of these mutants show that they are monogenic recessive mutations and there exist distinct difference in stomata apertures compared to wild type. These mutants in response to various environmental stresses and hormones were comprehen- sively investigated, which enables us to further un- derstand the cross-talk in different signal transduction pathways.     

The mec-4 gene is a member of a family of Caenorhabditis elegans genes that can mutate to induce neuronal degeneration.

Three dominant mutations of mec-4, a gene needed for mechanosensation, cause the touch-receptor neurons of Caenorhabditis elegans to degenerate. With deg-1, another C. elegans gene that can mutate to induce neuronal degeneration and that is similar in sequence, mec-4 defines a new gene family. Cross-hybridizing sequences are detectable in other species, raising the possibility that degenerative conditions in other organisms may be caused by mutations in similar genes. All three dominant mec-4 mutations affect the same amino acid. Effects of amino-acid substitutions at this position suggest that steric hindrance may induce the degenerative state.     

两种质粒编码的Borrelia burgdorfei寡肽结合蛋白(OppA)的表达和纯化

为了弄清Borrelia burgdorferi中OppA4和OppA5蛋白的生物学功能,oppAIV和oppAV基因分别被克隆并在大肠杆菌中表达．大肠杆菌BL21CodonPlus（DE3）-RIL被用来克服由A＋T丰富引起的密码偏差,十二烷基-β—D-麦芽糖苷和甘油分别用于提高脂蛋白的分离效果和维护蛋白的稳定性．经过金属离子亲和层析,OppA4和OppA5纯蛋白产量可达到1mg／L细胞以上．     

职业教育期刊入选CSSCI来源期刊的可能性分析与思考

职业教育期刊至今没有一种入选CSSCI来源期刊或其拓展版,这与职业教育作为一种教育类型的地位极不相配。从人大复印报刊资料教育学学科转载排名比较来看,职业教育核心期刊有能力入选CSSCI来源期刊。从《中国学术期刊影响因子年报(人文社会科学)》统计的影响因子数据比较来看,职业教育核心期刊的总体质量与教育学学科CSSCI来源期刊相比差距较大,与教育学学科CSSCI来源期刊拓展版相比也有一定差距。职业教育期刊要想成功入选CSSCI来源期刊,必须改变一刊多版、确定合适刊期、减少载文总量、调整栏目设置、主办方重视支持。     

Signal for T-cell differentiation to a CD4 cell lineage is delivered by CD4 transmembrane region and/or cytoplasmic tail.

Mature T cells express either CD4 or CD8 on their surface. Most helper T cells express CD4, which binds to class II major histocompatibility complex (MHC) proteins, and most cytotoxic T cells express CD8, which binds to class I MHC proteins. In the thymus, mature CD4+CD8- and CD4-CD8+ T cells expressing alpha beta T-cell antigen receptors (TCR) develop from immature thymocytes through CD4+CD8+ alpha beta TCR+ intermediates. Experiments using mice transgenic for alpha beta TCR suggest that the specificity of the TCR determines the CD4/CD8 phenotype of mature T cells. These results, however, do not indicate how a T cell differentiates into the CD4 or CD8 lineage. Here we show that the CD4 transmembrane region and/or cytoplasmic tail mediates the delivery of a specific signal that directs differentiation of T cells to a CD4 lineage. We generated transgenic mice expressing a hybrid molecule composed of the CD8 alpha extracellular domains linked to the CD4 transmembrane region and cytoplasmic tail. We predicted that this hybrid molecule would bind to class I MHC proteins through the extracellular domains but deliver the intracellular signals characteristic of CD4. By crossing our transgenic mice with mice expressing a transgenic alpha beta TCR specific for a particular antigen plus class I MHC protein, we were able to express the hybrid molecule in developing thymocytes expressing the class I MHC-restricted TCR. Our results show that the signal transduced by the hybrid molecule results in the differentiation of immature thymocytes expressing a class I-restricted TCR into mature T cells expressing CD4.     

CH4-CO2两步法直接合成乙酸的研究

研究担载Pd，Rh的催化剂在等温条件下采用CH4-CO2两步法直接合成乙酸的反应性能，利用IC，FTIR和XRD对反应产物及催化剂进行表征。研究结果表明，通过周期性的切换CH4和CO2反应气体可以克服热力学限制，而且催化剂没有积碳现象；反应温度为250℃时，Pd／Ti02和Rh／TiO2催化剂的活性最高。     

铁氰化钾、亚铁氰化钾和多联吡啶钌配合物静电自组装膜的研究

通过交替吸附多联吡啶钌配合物[Ru(bpy)2Hip]2+和铁氰化钾(K3[Fe(CN)6])、亚铁氰化钾(K4[Fe(CN)6]),制备了2种新型的静电自组装多层膜.通过紫外-可见吸收光谱和循环伏安图对自组装膜进行了表征.