间断低氧对大鼠下丘脑超微结构及前增食欲素水平的影响

目的探讨睡眠中间断低氧对大鼠下丘脑前增食欲素及受体水平的影响以及下丘脑超微结构的变化。方法大鼠分成对照组、间断低氧组和持续低氧组,分别给予吸入空气,持续低氧和间断低氧气体,并在实验开始后1d、3d、1w和4w应用RT-PCR方法测定大鼠下丘脑前增食欲素及受体水平,分析其间的变化关系,电镜观察下丘脑的超微结构变化。结果与对照组和持续低氧组比较,间断低氧4w后大鼠下丘脑前增食欲素mRNA水平明显降低,受体水平升高,但在持续低氧和对照组之间无明显差异。在低氧后1d、3d、7d后大鼠下丘脑前增食欲素mRNA降低,受体水平升高,在4w后,持续低氧组则接近正常。急性持续低氧大鼠超微结构变化更严重,而慢性间断低氧变化更持久。结论慢性间断低氧可以引起下丘脑前增食欲素下降及受体水平升高,急性持续低氧也可引起上述变化,而慢性持续低氧未引起增食欲素改变;慢性间断低氧大鼠下丘脑超微结构表现为严重而持久的变化。     

Herbogenomics: from traditional Chinese medicine to novel therapeutics

Traditional Chinese medicine (TCM) has a long history of development and application and has demonstrated on evidence basis its efficacy in the treatment of many diseases affecting multiple organ systems. In particular, TCM is effective in the prevention and treatment of chronic diseases and metabolic syndromes. However, the value of TCM has not been fully recognized worldwide due to the lack of definitive information of active ingredients in almost any TCM preparation. Novel functional genomics and proteomics approaches provide alternate perspectives on the mechanism of action of TCM. The target molecules on which TCM either activates or inactivates can be identified by functional genomics and proteomics, thus the affected critical signaling pathway cascades leading to effective recovery of chronic diseases can be studied. Several TCM preparations have been available for the treatment of liver fibrosis and cirrhosis, even advanced liver cirrhosis that has been shown to be irreversible and has no US-FDA approved therapy. In the TCM-treated livers with fibrosis and cirrhosis, some critical molecules that are significantly involved in the recovery can be identified through functional genomics and proteomics studies. These molecules become novel targets for drug discovery and development and candidates for the development of gene therapy. Gene therapy developed based on this strategy for the treatment of advanced liver fibrosis and cirrhosis in animal models has obtained promising results. This process thus establishes a herbogenomics approach to understand mechanisms of action of TCM and to identify effective molecular targets for the discovery and development of novel therapeutics.     

低温条件下中国野生拟南芥种群中CBF3与ROS浓度的相关性

活性氧(ROS)是植物光合作用和呼吸作用的副产物, 环境胁迫可加速植物体内ROS的产生, 造成植物细胞膜的过氧化, 同时给光反应中心II带来光伤害。RFOs是植物体内的1类寡聚糖家族, 其对环境胁迫的响应很可能与清除过剩的ROS相关。前期的研究显示, 由于中国长江流域野生拟南芥(Arabidopsis thaliana)种群中CBF3基因的变异, 种群的冰冻耐受性和体内RFOs含量的积累普遍低于Col生态型。研究表明, 长江流域种群中ROS代谢通路在低温处理后的表达与Col生态型相比发生了明显的分化, 并且植物体内ROS的浓度增高; 而将Col生态型中能正常响应环境冷信号的CBF3基因转入长江流域种群后, 转基因植株的冰冻耐受性得到显著提高, 体内RFOs积累亦增加, 而ROS浓度显著降低。这些结果说明, 低温条件下CBF3很可能通过直接调控植物体内RFOs的生物积累来参与调控下游过剩ROS的清除过程。中国长江流域野生拟南芥种群低温条件下体内ROS浓度的升高, 很可能是由于种群中CBF3基因发生了自然变异从而丧失了冷响应能力造成的。     

Detection of gene mutations related with drug resistance in Mycobacterium leprae from leprosy patients using Touch-Down (TD) PCR

The lack of methods to identify Mycobacterium leprae with the resistance against multi-drugs quickly and specifically has hindered effective chemotherapy against M. leprae infection. To screen M. leprae with resistance against multi-drugs, the Touch-Down (TD)-PCR has been used in this study. Sequences of the folP, rpoA, B, and gyrA, B genes were analyzed for isolates of M. leprae from leprosy patients in Korea. We amplified designated region of several genes in M. leprae involved in drug resistance and could obtain the PCR products of each gene. The mutations in the particular region of folP, rpoB, and gyrB gene were certified by TD-PCR single-stranded conformational polymorphism and DNA sequencing, respectively.     

Trypsin induces tumour necrosis factor-alpha secretion from a human leukemic mast cell line

Trypsin activating both proteinase-activated receptor (PAR) 2 and PAR4 plays an important role in inflammation. We have investigated the potential of trypsin to induce TNF-alpha secretion from the human leukemic mast cell line (HMC-1). HMC-1 cells co-express both PAR2 and PAR4, and their agonist trypsin signals to HMC-1 cells. Trypsin (100 nm), SLIGKV-NH(2) (100 microm, corresponding to the PAR2 tethered ligand), or GYPGQV-NH(2) (100 microm, corresponding to the PAR4 tethered ligand) induced tumour necrosis factor (TNF)-alpha secretion from HMC-1 cells. TNF-alpha secretion by trypsin was significantly blocked by pretreatment with 50 microm PD098059, MEK-1 inhibitor. Furthermore, trypsin stimulated the activation of extracellular signal-regulated kinase (ERK) in HMC-1 cells without any detectable activation of c-Jun N-terminal kinase (JNK) and p38 MAP kinase homologue. These results show that trypsin may induce TNF-alpha secretion following activation of ERK via both PAR2 and PAR4 on HMC-1 cells.     

Enhanced immunodetection of cell-free synthesized erythropoietin under denaturing conditions

A monoclonal antibody produced by hydridoma cell line, ATCC HB8209, was used to detect and purify erythropoietin synthesized in a cell-free system. The antibody was raised against the N-terminal 20 residues of erythropoietin. It retained anti-erythropoietin activity in 6 M urea in which most of the cell-free synthesized erythropoietin became soluble and gave an enhanced activity of the antibody.     

18S rDNA的研究进展及其在膜翅目昆虫分子系统学中的应用

本文综述了18S rDNA的研究进展,主要包括了18S rDNA的结构研究,18S rDNA的网络资源利用和18S rDNA在膜翅目昆虫中的应用。     

Comparative study of two thioredoxin peroxidases from disk abalone (Haliotis discus discus): cloning, recombinant protein purification, characterization of antioxidant activities and expression analysis

Thioredoxin peroxidase (TPx), also named peroxiredoxin (Prx), is an important peroxidase, which can protect organisms against various oxidative stresses. Two TPxs were isolated from a disk abalone (Haliotis discus discus) cDNA library, named as AbTPx1 and AbTPx2, respectively. AbTPx1 and AbTPx2 consist of 1315 and 1045 bp full-length cDNA with 753 and 597 bp open reading frames encoding 251 and 199 amino acids, respectively. The TPx signature motif 1 (FYPLDFTFVCPTEI) and motif 2 (GEVCPA) were conserved in both AbTPx1 and AbTPx2 amino acid sequences. Purified recombinant abalone TPx fusion proteins catalyzed the reduction of H2O2 and butyl hydroperoxide in peroxidase assays. Furthermore, both AbTPx fusion proteins were shown to protect super-coiled DNA from damage by metal-catalyzed oxidation (MCO) in vitro. Escherichia coli cells transformed with AbTPx1 and AbTPx2 coding sequences in pMAL-c2x showed resistance to H2O2 at 0.8 mM concentration by in vivo H2O2 tolerance assay. AbTPx1 and AbTPx2 mRNA were constitutively expressed in gill, mantle, abductor muscle and digestive tract in a tissue specific manner. Additionally, both TPxs mRNA were up-regulated in gill and digestive tract tissues against H2O2 at 3h post injection. The results indicate that AbTPx1 and AbTPx2 gene expressions are induced by oxidative stress and their respective proteins function in the detoxification of different ROS molecules to maintain efficient antioxidant defense in disk abalone.     

Magnesium ion is an effective inhibitor of the binding of Escherichia coli to heparin

We investigated the effects of ions and temperature on the binding of E. coli to heparin using a chemiluminescence electrophoretic mobility shift assay. We found that magnesium ion is an effective inhibitor of the binding. The method can be readily applied to discover agents that can block the binding.