Influence of Fermentation and Drying Materials on the Contamination of Cocoa Beans by Ochratoxin A

Ochratoxin A (OTA) is a mycotoxin produced mainly by species of Aspergillus and Penicillium. Contamination of food with OTA is a major consumer health hazard. In Côte d’Ivoire, preventing OTA contamination has been the subject of extensive study. The current study was conducted to evaluate the influence of fermentation and drying materials on the OTA content in cocoa. For each test, 7000 intact cocoa pods were collected, split open to remove the beans, fermented using 1 of 3 different materials, sun-dried on 1 of 3 different platform types and stored for 30 days. A total of 22 samples were collected at each stage of post-harvesting operations. The OTA content in the extracted samples was then quantified by high-performance liquid chromatography. OTA was detected in beans at all stages of post-harvesting operations at varying levels: pod-opening (0.025 ± 0.02 mg/kg), fermentation (0.275 ± 0.2 mg/kg), drying (0.569 ± 0.015 mg/kg), and storage (0.558 ± 0.04 mg/kg). No significant relationships between the detected OTA level and the materials used in the fermentation and drying of cocoa were observed.     

霍乱弧菌04-5a糖发酵激活蛋白编码基因分析

目的 比较霍乱弧菌04-5a株糖发酵激活蛋白编码基因与霍乱流行株与非流行株相关序列的差异,明确其基因型.方法 采用基因克隆测序方法,对霍乱弧菌04-5a株糖发酵激活蛋白编码基因进行序列分析,并与相关序列进行比较.结果 霍乱弧菌04-5a株糖发酵激活蛋白编码基因由771个碱基对组成,编码258个氨基酸的多肽,流行株和非流行株相关序列比较发现,04-5a株与流行株两者基因完全相同,与非流行株在334、622和666位核苷酸碱基的具有差异,第666位碱基的差异导致了氨基酸的不同,在非流行株与流行株分别为丙氨酸与苏氨酸.结论 霍乱弧菌04-5a株糖发酵激活蛋白编码基因序列符合流行株基因特征,在非流行株与流行株第666位碱基差异可能与其致病性及流行有关,值得深入研究.     

Kinetics of lactose fermentation in milk with kombucha starter

The aim of this research was to investigate the effect of new, non-conventional starter culture on the kinetics of the lactose transformation during milk fermentation by kombucha, at pH 5.8; 5.4; 5.1; 4.8; and 4.6, at two different temperatures 37 °C and 42 °C. Milk fermentation at 42 °C lasted significantly shorter (about 5 h, 30 min) compared to the fermentation at 37 °C. Changes of lactose concentration at the both temperatures are consisting of two retaining stages and very steep decline in–between. The analysis of the rate curves showed that the reaction rate passes through the maximum after 9 h, 30 min at 37 °C and after 4 h at 42 °C. The sigmoidal saturation curve indicates a complex kinetics of lactose fermentation by kombucha starter.     

aveD基因失活提高阿维菌素工业菌株B组分产量

目的 破坏除虫链霉菌aveD基因,提高阿维菌素B1a的发酵单位.方法 将aveD基因内部364bp的SmaⅠ-SmaⅠ片段以相反的方向插入到原位置,构建重组质粒pUAmT-D7,并转化到阿维菌素工业生产菌Streptinomyces avermitilis G-8,筛选得到ave基因失活的基因工程菌G8-17.结果 发酵结果表明,G8-17不产维菌素A组分,而B组分的发酵单位则有相应的提高,其中有效组分B1a的发酵单位提高了33.6％.结论 aveD基因内部片段倒位没有影响下游与之共转录的基因aveF的表达,同时能有效阻断阿维菌素A组分的产生,提高B组分的发酵单位.     

海洋来源放线菌Actinoalloteichus cyanogriseus WH1-2216-6 产浅蓝霉素A的发酵条件优化

目的 对海洋来源放线菌Actinoalloteichus cyanogriseus WH1-2216-6 产浅蓝霉素A的发酵条件进行优化,提高浅蓝霉素A的产量。方法 对培养基的组成、接种量、起始pH、盐度、发酵时间、前体浓度及大孔吸附树脂添加量等条件的研究,通过单因素和正交试验,选择最优发酵条件;结果 获得了浅蓝霉素A的最佳发酵条件,培养基组成(可溶性淀粉20 g,甘油20 g,蛋白胨20 g,CaCO₃2 g,2-吡啶甲酸400 mg,XAD-16大孔吸附树脂50 g,陈海水1 L)、装液量150/500 mL(体积分数)、5 d种龄、3.3%盐度、起始pH=7.5、摇床(180 r/min,28℃)发酵12 d。结论 以最佳发酵条件发酵,优化后的浅蓝霉素A的产量为优化前的7.0倍,达到610.5 mg/L。     

基因工程菌发酵表达核苷磷酸化酶条件的优化

目的 优化苷磷酸化酶（包括嘌呤和嘧啶核苷磷酸化酶）基因工程菌的发酵表达条件。方法通过工程菌摇瓶培养,测定吸光度D值,考马斯亮蓝（Bradford）法测定蛋白,SDS—PAGE电泳和凝胶成像扫描分析表达量,优化表达条件;通过正交试验优化50L发酵罐发酵条件。结果摇瓶培养起始pH为7．0～7．2,于30℃培养4h,加入终浓度为0．4mmol／L的异丙基硫代半乳糖苷（IPTG）诱导8h后收获菌体,可得到较高的生物量和重组酶蛋白表达量。50L发酵罐的最佳条件为起始pH为7．0～7．2,于32oC培养4h,加入终浓度为0．4mm01／L的IPTG诱导9h后收获菌体,每升发酵液可得2g以上的酶蛋白。结论基因工程菌发酵表达核苷磷酸化酶产量较高,可工业化生产．为酶法合成核苷酸类似物的研究奠定了基础。     

GI Symptoms in Infants Are a Potential Target for Fermented Infant Milk Formulae: A Review

Besides pre- and pro-biotic-containing infant formulae, fermented infant formulae are commonly used to relieve or prevent symptoms of gastrointestinal (GI) discomfort in young infants. During the fermentation process in cow’s milk-based formulae, the beneficial bacteria modulate the product by forming several beneficial compounds, which contribute to the alleviation of the symptoms observed. This review summarizes the clinical evidence on the impact of fermented infant formulae on common pediatric GI-symptoms. The potential mechanisms involved are discussed: i.e., the lactose and protein (in-) digestibility, effects on gastric emptying and gut transit and modulation of the colonic microbiota. Although initial evidence indicates a beneficial effect of fermented formulae on GI discomfort in newborns, validation and confirmation of the clinical proof obtained so far is warranted, as well as further research to (more fully) understand the mode of action.     

虫草多糖对平阳霉素诱导的肺纤维化小鼠的影响

目的 研究虫草多糖抗小鼠肺纤维化的作用。方法 采用气管注射平阳霉素制作小鼠肺纤维化模型,酶联免疫吸附法测定血清白介素1受体抑制剂（interleukin-1 receptor antagonist,IL-1RA）含量,碱水解法测定肺组织中羟脯氨酸（hydroxyproline,Hyp）含量,Masson染色法观察肺组织胶原沉积情况。结果 与肺纤维化模型组相比,虫草菌粉组、虫草总多糖组和虫草多糖[分子量（molecular mass,MW）<2×10⁵]组血清中IL-1RA水平明显升高,肺组织中Hyp含量明显降低;虫草总多糖组和虫草多糖（MW<2×10⁵）组肺组织纤维化面积明显减小。结论 虫草多糖具有明显的抗小鼠肺纤维化作用。     

乌灵菌发酵液抗辐射功能研究

目的 研究乌灵菌发酵液对小鼠抗辐射功能的影响。方法 通过迟发型超敏反应（delayed type hypersensitivity,DTH）、脾淋巴细胞增殖转化试验、血清溶血素和凝集素水平检测、碳粒廓清试验观察乌灵菌发酵液对免疫功能的影响;通过检测辐射损伤小鼠外周血液学指标、骨髓有核细胞数、骨髓细胞微核率与血清及脏器中的脂质过氧化产物丙二醛（MDA）含量观察乌灵菌发酵液对氧化应激与造血功能的影响。结果 与正常组相比,乌灵菌发酵液3,0.6 g·kg^-1剂量组DTH反应明显增强（P<0.01）,脾淋巴细胞增殖转化功能、血清溶血素、碳粒廓清指数及胸腺系数显著提高（P<0.05或P<0.01）;与模型组相比,给药组骨髓有核细胞数与骨髓细胞微核率无明显差异,血清与心脏MDA含量显著降低（P<0.05或P<0.01）,白细胞数量显著增加（P<0.01）,结论 乌灵菌发酵液可能通过增强机体免疫调节能力与造血功能来发挥抗辐射功效。     

响应面法结合满意度函数优化白囊耙齿菌发酵培养基

采用响应面法和满意度函数,以期望值作为响应值,提高白囊耙齿菌发酵的菌丝体干重以及胞内多糖、甘露醇、腺苷和蛋白质的含量.通过单因素法优化白囊耙齿菌发酵培养基中的碳、氮源和无机盐,然后进行部分因子试验考察培养基组分对菌株发酵的影响,并应用中心组合设计试验优化培养基,获得最佳培养基配方(%):乳糖2.94,酵母浸粉1.5,牛肉膏1.5,KH2PO4·3H2O 0.065,MgSO4·7H2O 0.06,NaCl 0.000 8,VB1 0.028 9.模型预测最佳培养基配方下白囊耙齿菌的发酵期望值为0.624,3次验证试验平均值为0.617 7,是优化前的5.27倍,与模型预测值间的误差为1.01%.