模拟医学生物化学实验血清标本的探讨

用蛋白胨、三油酸甘油酯、鼠肝、葡萄糖等材料模拟血清标本,通过测定该血清中蛋白、血脂、谷丙转氨酶、血糖以及部分物理参数,探讨了模拟血清从外观和实验项目上满足实验教学的可行性。结果表明,模拟血清实用、简便易得,既能解决医学生物化学实验教学标本来源困难问题,又能防止实验室污染和节省大量实验经费。     

胰酶水解干酪素的动力学行为

研究了胰酶水解干酪素制备蛋白胨过程中胰酶在不同温度下的失活行为,以及底物浓度对反应速率和平衡的影响,ｐＨ对反应浓度和平衡的影响。胰酶在４０℃下４ｈ基本不丧失水解大分子的活力;在５０℃,ｍｉｎ、５５℃,１００ｍｉｎ、６０℃,９０ｍｉｎ完全丧失对大分子的水解活性。胰酶短时间在高温下丧失的活性,当其返回到４０℃时可部分恢复。底物和产物对反应有抑制作用。底物初始浓度高,最终平衡转化率低。当ｐＨ８时的反应速     

In vitro batch cultures of gut microbiota from healthy and ulcerative colitis (UC) subjects suggest that sulphate-reducing bacteria levels are raised in UC and by a protein-rich diet

Imbalances in gut microbiota composition during ulcerative colitis (UC) indicate a role for the microbiota in propagating the disorder. Such effects were investigated using in vitro batch cultures (with/without mucin, peptone or starch) inoculated with faecal slurries from healthy or UC patients; the growth of five bacterial groups was monitored along with short-chain fatty acid (SCFA) production. Healthy cultures gave two-fold higher growth and SCFA levels with up to ten-fold higher butyrate production. Starch gave the highest growth and SCFA production (particularly butyrate), indicating starch-enhanced saccharolytic activity. Sulphate-reducing bacteria (SRB) were the predominant bacterial group (of five examined) for UC inocula whereas they were the minority group for the healthy inocula. Furthermore, SRB growth was stimulated by peptone presumably due to the presence of sulphur-rich amino acids. The results suggest raised SRB levels in UC, which could contribute to the condition through release of toxic sulphide.     

猪血超氧化物歧化酶、血红素和蛋白胨分离制备的研究

目的:研究从猪血分离制备超氧化物歧化酶(SOD)、血红素(Hematin)和蛋白胨(peptone)的工艺流程。方法:SOD的分离纯化采用加热变性、盐析和凝胶过滤的方法;血红素的提取采用鞣酸法;蛋白胨的制备采用碱性酶解法。结果:根据这一工艺流程,能从1000ml猪血的红细胞中获得总活力为25.8×104U、比活力为1.19×104U/mg的SOD和产量达2678mg、纯度达92.3%的血红素,并且还从猪血总蛋白中制备了含Arg、Leu、Lys、Phe、Val丰富的蛋白胨。结论:从猪血中成功制备了产率与纯度较高的SOD、血红素以及营养价值较高的蛋白胨。     

Acanthamoeba castellanii supports extracellular survival of Helicobacter pylori in co-culture

This study aimed to demonstrate whether Helicobacter pylori is able to survive in co-culture with a protozoan, Acanthamoeba castellanii, in order to further investigate a possible aqueous environmental mode of transmission. Numbers of H. pylori in co-culture with A castellanii were assessed by colony forming unit (CFU) assay and cell morphology was observed by electron microscopy. Viable and intact H. pylori in co-culture were detected and the number of H. pylori in co-culture with A. castellanii was significantly higher than in bacterial single culture. It was also shown that co-culture of H. pylori with A. castellanii physically separated by a filter membrane negated this survival effect, suggesting that adherence of H. pylori to A. castellanii affects its survival. Scanning electron microscopy revealed helical forms of H. pylori in co-culture with A. castellanii, but not in single culture. These results imply that mutual interaction between H. pylori and A. castellanii in the environment is critical for survival of H. pylori. In addition, the H. pylori gene expression profile was found to differ between single and co-cultured cells using RNA-sequence analysis.     

一些培养基添加剂对解脲支原体生长的影响

对几种培养基添加剂对解脲支原体生长的影响进行研究。结果表明：狗血清、鸡蛋黄、鸡蛋清与小牛血清一样，有促进解脲支原体生长的作用，培养基中添加１０％狗血清、２～４％鸡蛋黄，２０％鸡蛋清，或１％～２％鸡蛋黄和５％～１０％鸡蛋清，可获得与添加１０％小牛血清相似的效果；鲜酵母浸液也能促进其生长，脲浓度从０．１％增至０．３％，有利于其生长，而蛋白胨酵母浸汁（工业产品）则有抑制作用。     

Expression of an anti-CD33 single-chain antibody by Pichia pastoris

CD33 is a cell surface glycoprotein expressed on cells of myelomonocytic lineage, leukaemic cells, but not haematopoietic stem cells. By virtue of its expression pattern, CD33 has become a popular target for new immunotherapeutic approaches to treat acute myeloid leukaemia. The methylotrophic yeast Pichia pastoris strain KM71H was used to produce an anti-CD33 single chain variable fragment (scFv), with the intention of conjugation to a radioisotope, for therapeutic use. To direct secreted expression of the anti-CD33-scFv the alpha-mating factor secretory signal sequence (alpha-MF) was used, with constructs containing a complete (CS) and incomplete (INCS) cleavage site to accommodate the potential outcomes of dibasic endopeptidase, Kex2, and dipeptidyl amino peptidase, Ste13, processing. The anti-CD33-scFv was expressed in BMMY cultures using both constructs, with a final yield of 48 mg/l (CS) and 11 mg/l (INCS). N-terminal sequencing showed that the CS-scFv had not been cleaved by Ste13, leaving amino acids EAEA at the N-terminus. The INCS-scFv construct produced a mixture of 50% authentic scFv and 50% with 11 amino acids from the alpha-MF remaining at the N-terminus. Despite the aberrations in alpha-MF processing, the anti-CD33-scFv's produced from both constructs were found to be functional. Flow cytometry and Biacore analysis demonstrated binding to target antigen CD33 on the surface of human leukaemic cell line HL-60, and to recombinant soluble CD33 respectively.     

Limited Mobility of Membrane Receptors of Adhered or Proteose Peptone-Stimulated Macrophages

The mobility of the membrane receptors of macrophages, obtained from normal and proteose peptone-stimulated mice, was studied by counting the cells which form patches or caps after incubation with anti-H-2^a antibody or soybean agglutinin (SBA). The test was carried out with macrophage suspension by the indirect fluorescence method. When macrophages from unstimulated donors were used, the antibodies against H-2^a antigens bind at 4°C to the surface of the macrophages in the form of small aggregates; only with SBA lectin a larger percentage of cells (20 %) does form caps even at this low temperature. After heating the cells to 37#x00B0;C, a significant increase in the number of cells with receptors in caps was observed in the control mice. When macrophages from stimulated donors were used, no cap formation was observed with any of the ligands, even after a 120-minute-incubation; the ligand-receptor complexes form patches predominantly on the membrane. The pretreatment of macrophages with colchicine did not lead to a cap formation. A similar inhibition of the capping phenomenon also occurred with macrophages obtained from unstimulated mice, but tested in a monolayer.     

蛋白胨对碘伏有效碘与杀菌效果的影响

将不同厂家生产的蛋白胨加进碘伏溶液中 ,观察其对有效碘与杀菌效果的影响。结果 ,0 1%蛋白胨可使碘伏溶液有效碘含量减少率≥ 2 4 % (6 0 / 2 50 ) ,随不同厂家生产的蛋白胨而异 ,因而相同浓度不同品牌蛋白胨对碘伏杀灭大肠杆菌效果的影响程度不同。