西索米星发酵液的薄层层析生物显影测定

通过对检定菌的敏感性，检定培养基、展开剂和发酵液样品等影响因素的考察，建立了一种检测发酵液中西索米星浓度的方法。采用短小芽孢杆菌为生物显影检定菌，双层琼脂扩散法于37℃培养16～18h，控制检定培养基的PH为7．5～8．0，发酵液样品pH为4．5～7，0，展开剂为15％的KH2PO4，点样量为10μl，薄板和菌层接触时间为20min等检定条件，能用于发酵液中西索米星效价的直接测定，其线性回归方程为 Y＝0．0115X＋1．747，r=0．9877。在相同条件下，对536μg/ml的西索米星标准液连续测定6次，测定结果为（531．0 ±12．7）μg/ml，RSD=3．28％，该法具有较高的实验重复性和准确性，分析稳定性基本符合要求。     

Epitope mapping of a PrP(Sc)-specific monoclonal antibody: identification of a novel C-terminally truncated prion fragment

Monoclonal antibodies (mAbs) against prion proteins (PrPs) are indispensable in research and diagnosis of prion diseases, however the majority of these bind both the cellular (PrP^C) and the disease-associated (PrP^Sc) isoforms. According to the widely accepted protein-only hypothesis the two isoforms share the same sequence, but differ in their conformation. In the present study we set to determine the critical binding residues of our PrP^Sc-specific mAbs with the view of discerning which residues play a key role in the conformational transition between PrP^C and PrP^Sc. Focussing on the V5B2 mAb that provided differential labelling of prion-affected tissue from individuals positive for transmissible spongiform encephalopathies, we performed alanine scanning and phage-display epitope mapping to elucidate the antigenic determinants of this mAb and gain insight into its specificity on a molecular level. We observed that instead of discriminating between the two prion protein isoforms based on conformational differences, V5B2 binds a previously uncharacterized C-terminally truncated form of PrP^Sc that ends with the residue Y226, which we named PrP226*. The addition of a single C-terminal amino-acid residue completely abolished V5B2 binding, while Western blots using recombinant full-length PrPs and PrPs terminating at Y226 confirmed that the V5B2 mAb discriminates between the two based on their difference in length.     

浅谈灭菌后发酵培养基带菌状况分析及预防

目的在药品发酵生产中较易染菌,刚灭菌后的培养基仍有带菌危险,危害较大,通过本文阐述,为发酵生产控制提供借鉴。方法对灭菌后发酵培养基带菌状况分析．杂菌污染途径及防治等阐述,联系实际进行杂菌污染的防控。结果发酵生产过程要根据不同染菌原因进行防治,有的放矢。结论发酵染菌后要找出染菌原因,积极采取必要措施,把杂菌消灭在发生之前。     

阿卡波糖的研究进展

阿卡波糖作为2型糖尿病的一线治疗药物,已经被广泛用来降低餐后高血糖,临床疗效可靠,具有广阔的应用前景。本文从阿卡波糖的发酵制备、分离工艺及其衍生物的开发应用等方面对阿卡波糖的研究进展进行了综述,以期为阿卡波糖的临床应用以及新的降糖药物的开发提供理论依据。     

中国被毛孢发酵物对小鼠镇静作用的实验研究

目的观察中国被毛孢发酵物对小鼠的镇静作用。方法采用延长阈剂量戊巴比妥钠的睡眠时间方法及与阈下剂量戊巴比妥钠协同作用法,研究中国被毛孢发酵物的镇静作用。结果中国被毛孢发酵物能不同程度地延长戊巴比妥钠对小鼠的睡眠时间和增加戊巴比妥钠阈下剂量对小鼠的入睡个数。结论中国被毛孢发酵物对小鼠具有镇静作用。     

Effect of Fermented Soybean Meal on Intestinal Morphology and Digestive Enzyme Activities in Weaned Piglets

The objective of the current experiment was to investigate the effect of Bacillus subtilis fermented soybean meal (FSBM) on intestinal morphology and digestive enzyme activities in piglets. Sixty crossbred (Duroc×Landrance×Yorkshire) piglets at an average weight of 8.62 kg were randomly allotted to two treatments and fed diets containing soybean meal (SBM) and FSBM, respectively. At the end of the experimental period, six piglets of each treatment were slaughtered humanly to collect the contents and tissue samples at three different locations in small intestine. Light microscopy and scanning electron indicated that piglets fed FSBM had a higher (P<0.05) villus height at three different locations of small intestine and had la ower (P<0.05) crypt depth in the duodenum compared to piglets fed SBM. The results showed that activities of total protease and trypsin at the duodenum and jejunum of piglets fed with FSBM increased (P<0.05) compared with the control. The trypsin activity in the pancreas of piglets decreased (P<0.05) when they were fed with FSBM. The results showed that FSBM improved intestinal morphology and digestive enzyme activities in weaned piglets.     

Soluble proteins produced by probiotic bacteria regulate intestinal epithelial cell survival and growth

BACKGROUND & AIMS: Increased inflammatory cytokine levels and intestinal epithelial cell apoptosis leading to disruption of epithelial integrity are major pathologic factors in inflammatory bowel diseases. The probiotic bacterium Lactobacillus rhamnosus GG (LGG) and factors recovered from LGG broth culture supernatant (LGG-s) prevent cytokine-induced apoptosis in human and mouse intestinal epithelial cells by regulating signaling pathways. Here, we purify and characterize 2 secreted LGG proteins that regulate intestinal epithelial cell antiapoptotic and proliferation responses. METHODS: LGG proteins were purified from LGG-s, analyzed, and used to generate polyclonal antibodies for immunodepletion of respective proteins from LGG-conditioned cell culture media (CM). Mouse colon epithelial cells and cultured colon explants were treated with purified proteins in the absence or presence of tumor necrosis factor (TNF). Akt activation, proliferation, tissue injury, apoptosis, and caspase-3 activation were determined. RESULTS: We purified 2 novel proteins, p75 (75 kilodaltons) and p40 (40 kilodaltons), from LGG-s. Each of these purified protein preparations activated Akt, inhibited cytokine-induced epithelial cell apoptosis, and promoted cell growth in human and mouse colon epithelial cells and cultured mouse colon explants. TNF-induced colon epithelial damage was significantly reduced by p75 and p40. Immunodepletion of p75 and p40 from LGG-CM reversed LGG-CM activation of Akt and its inhibitory effects on cytokine-induced apoptosis and loss of intestinal epithelial cells. CONCLUSIONS: p75 and p40 are the first probiotic bacterial proteins demonstrated to promote intestinal epithelial homeostasis through specific signaling pathways. These findings suggest that probiotic bacterial components may be useful for preventing cytokine-mediated gastrointestinal diseases.     

基于抗体等重组蛋白表达产品的哺乳动物细胞大规模发酵技术

抗体等重组蛋白产品是以基因工程和细胞工程为关键技术的生物技术产品,其特异性高、均一性好、靶点明确,广泛应用于各类重大疾病、尤其是对肿瘤治疗。目前,在FDA批准的32种抗体药物治疗疾病的分类中,肿瘤类疾病占32％、免疫性疾病占37％、器官移植疾病占11％、感染性疾病占8％、心血管疾病占4％、其他疾病占6％。     

Mead production: Selection and characterization assays of Saccharomyces cerevisiae strains

Mead is a traditional drink, which results from the alcoholic fermentation of diluted honey carried out by yeasts. However, when it is produced in a homemade way, mead producers find several problems, namely, the lack of uniformity in the final product, delayed and arrested fermentations, and the production of “off-flavours” by the yeasts. These problems are usually associated with the inability of yeast strains to respond and adapt to unfavourable and stressful growth conditions. The main objectives of this work were to evaluate the capacity of Saccharomyces cerevisiae strains, isolated from honey of the Trás-os-Montes (Northeast Portugal), to produce mead. Five strains from honey, as well as one laboratory strain and one commercial wine strain, were evaluated in terms of their fermentation performance under ethanol, sulphur dioxide and osmotic stress. All the strains showed similar behaviour in these conditions. Two yeasts strains isolated from honey and the commercial wine strain were further tested for mead production, using two different honeys (a dark and a light honey), enriched with two supplements (one commercial and one developed by the research team), as fermentation media. The results obtained in this work show that S. cerevisiae strains isolated from honey, are appropriate for mead production. However it is of extreme importance to take into account the characteristics of the honey, and supplements used in the fermentation medium formulation, in order to achieve the best results in mead production.     

微生物产生的淀粉酶抑制制研究Ⅱ．发酵、分离与理化性质

Ｓ－２－３５菌株产生的淀粉酶抑制剂对人体内的ａ－淀粉酶、唾液酸酶有明显的抑制作用。该产生菌在２８℃摇瓶发酵时，碳源利用率高于氮源利用率。发酵４８小时后，菌丝的生长速度随着碳源利用率的加速而加快。淀粉酶抑制剂的含量在２５小时后迅速提高，并在７２小时达最高峰。发酵液经活性炭吸附，ＤＥＡＥ－５２纤维索、ＣＭ－３２纤维素和ＳｅｐｈａｄｅｘＧ－２５层析后的活性部分经ＨＰＬＣ得三个活力峰。显色反应表明对茚三酮、双缩脉呈阴性反应，对吐伦、间苯二酚、Ａｎｔ－ｈｒｏｎｅ和ＫＭｎＯ＿４呈阳性反应。紫外光谱呈末端吸收，红外光谱在３３９１、１４１０、１０３０及９２７ｃｍ￣（－１）处有吸收峰。质谱测定Ａ组分分子量为９４４。