一株产絮凝剂不动杆菌的筛选及其絮凝特性

从活性污泥中筛选出一株高效的微生物絮凝剂产生菌, 鉴定为鲍曼不动杆菌。蚕豆根尖细胞微核试验未显示该菌株所产絮凝剂具有遗传毒性。该菌产絮凝剂的最佳碳源和氮源分别为葡萄糖和酵母浸出汁, 培养时间为24 h。在絮凝体系中加入Ca2+能明显提高发酵液的絮凝率。在pH为8.0时对高岭土悬浊液和污水具有良好的絮凝效果。     

一株产絮凝剂不动杆菌的筛选及其絮凝特性

从活性污泥中筛选出一株高效的微生物絮凝剂产生菌,鉴定为鲍曼不动杆菌.蚕豆根尖细胞微核试验未显示该菌株所产絮凝剂具有遗传毒性.该菌产絮凝剂的最佳碳源和氮源分别为葡萄糖和酵母浸出汁,培养时间为24 h.在絮凝体系中加入Ca2 能明显提高发酵液的絮凝率.在pH为8.0时对高岭土悬浊液和污水具有良好的絮凝效果.     

利用污泥提取液制备微生物絮凝剂

以污水厂剩余污泥作为培养基原料,经过一系列处理,探索微生物絮凝剂产生菌的最适发酵培养基配方,结果表明,污泥预处理条件以pH 12碱解条件最优,碳氮源产出量最大,补加8 g/L葡萄糖后灭菌,微生物絮凝剂产生菌LLin6可正常产絮,絮凝率达91.55%。该结果为降低微生物絮凝剂的制备成本,并实现污泥的减量化和污泥资源化利用提供了基础。     

假单细胞GX4—1利用鱼粉废水产絮凝剂的研究

研究了假单胞菌（Pseudomonas sp.) GX4-1利用鱼粉废水产生絮凝剂的条件,结果表明,适宜条件为废水COD浓度为10g／L左右、初始pH为7－9、培养温度为30℃、摇床转速为100－250r/min,此时的絮凝率可高达99．5％。同时发现在废水培养基灭菌的条件下,该菌仍能产生高效的絮凝剂。该菌利用鱼粉废水产生的絮凝剂对高岭土悬液、土壤悬液和细活性炭粉末悬液和电瓷厂污水均有较好的絮凝作用。     

絮凝剂产生菌的筛选、培养及产物性质研究

从活性污泥中筛选出一株高效产絮凝剂菌株,经鉴定为嗜温鞘氨醇杆(Sphingobacterium thalpophilum).采用单因素实验,结果显示该菌产絮凝荆的最适碳源为可溶性淀粉,最适氮源为硫酸铵,最适初始pH值7.0,最适培养温度为30℃.性质研究分析显示,絮凝剂纯品的热稳定性差,其在pH值2.0～8.0的范围内可以保持较高的絮凝活性.     

微生物絮凝剂的菌种培养及絮凝活性研究

从活性污泥中分离出具有絮凝活性的菌种作为微生物絮凝剂,通过将其对高岭土悬浊液进行絮凝活性测定,得出了适于该菌产絮凝剂的最佳培养基为：以浓度为1．5％的葡萄糖作为碳源,以NH4Q0．06％ 酵母膏0．04％相组合为氮源,以浓度0．3％的KH2PO4作为无机营养物质,其它培养条件pH值为7～8,温度为30℃,摇床转速为180r／min。并将培养好的菌液用于多种废水净化,试验结果表明：其絮凝率与去除率均达90％以上,具有较好的净化效果。     

产微生物絮凝剂的菌株筛选、鉴定及发酵条件优化

微生物絮凝剂是一类新型的水处理制剂,因其具有高效、无毒、易降解等特点,已成为水处理剂开发的研究热点。为了扩大微生物絮凝剂的种类,本研究从活性污泥和土壤样品中筛选絮凝剂产生菌,最终获得一株具有絮凝活性的菌株,通过16S rDNA鉴定,该菌株为蒙氏假单胞菌(Pseudomonas monteilii),因此命名为P. monteilii YR-1。利用单因素实验和正交试验对该菌株的发酵条件进行了优化,其最佳碳、氮源分别为25 g/L葡萄糖和2 g/L复合氮源(酵母浸粉:尿素:硫酸铵=5:5:2),培养基初始pH值为10,培养温度为28℃,发酵时间为72 h。在最佳培养条件下,其发酵液的絮凝率从37.68%提高到63.52%。这是关于蒙氏假单胞菌产絮凝剂的首次报道。     

高效微生物絮凝剂D6对屠宰废水的应用研究

筛选出一株针对屠宰废水有高效絮凝活性的微生物絮凝剂产生菌,并对其所产微生物絮凝剂D6进行单因子絮凝条件优化和正交试验优化得到最佳絮凝条件。絮凝条件包括:微生物絮凝剂D6投加量、pH、金属离子种类、1%CaCl₂投加量。试验中发现碱性环境是微生物絮凝剂D6发挥絮凝活性的前提,表明微生物絮凝剂D6分子链的充分伸展对絮凝作用起决定因素,因此微生物絮凝剂D6的絮凝机理为吸附架桥作用。其最佳絮凝条件为微生物絮凝剂D6的投加量为25mL·L^-1,1%CaCl₂投加量55mL·L^-1,pH为8。在最佳絮凝条件下,絮凝率为96.6%,浊度去除率为97.8%,SS去除率为92.6%。     

微生物絮凝剂产生菌的筛选及其絮凝特性初步研究

目的:从海口市白沙门污水处理厂活性淤泥中分离微生物絮凝剂产生菌,并对其絮凝特性进行初步研究。方法:稀释平板法进行菌株分离,高岭土悬浊法进行菌株的筛选以及菌株产絮凝剂特性、絮凝剂活性成分和热稳定性的研究;通过形态学和生理生化试验进行菌株的初步鉴定。结果:筛选到2株具有高絮凝活性的产生菌XN-6和XN-8,分别属于乳杆菌属(Lactobacillus sp.)和不动杆菌属(Acinetobater sp.)。菌株XN-6和XN-8发酵液絮凝率最高时,菌株XN-6的最佳pH值、最适温度和最佳转速分别为7、30℃、120r/min;XN-8的最佳pH值、最适温度和最佳转速分别为8、32℃、120r/min;菌株产絮凝剂活性成分热稳定性较差。菌株XN-6和XN-8单独处理污水的絮凝率分别为81.01%和76.78%,联合处理污水的絮凝率为79.08%,基本上不存在协同作用。结论:菌株XN-6和XN-8可作为原始菌株用于开发微生物絮凝剂,有望能应用于污水的处理。     

乌勇布拉克盐湖嗜盐古菌絮凝效果筛选及活性检测

【目的】从嗜盐古菌中筛选可产生生物絮凝剂的菌株,对发酵液、上清液、菌悬液、胞外聚合物的絮凝作用进行检测,筛选能够适应高盐废水处理,且具有广谱盐度及pH作用范围的微生物絮凝剂。【方法】以新疆乌勇布拉克干盐湖沉积物为研究对象,利用纯培养方法对嗜盐古菌进行分离,对絮凝菌株进行初筛及16S rRNA基因测序,构建系统进化树,初步判断菌株分类地位;复筛检测不同生物材料的絮凝效果;选择絮凝效果较好的生物材料,检测其盐度、pH的絮凝效果稳定性。【结果】采用纯培养方法共分离到28株嗜盐古菌,絮凝初筛共筛选出16株嗜盐古菌,分布于碱线菌属(Natrinema)、盐缓长菌属(Halopiger)和盐土生菌属(Haloterrigena)。菌株发酵液、上清液、菌悬液、胞外聚合物具有不同程度的絮凝效果。菌株A279-1、A133、RP33、NGA0064、RM-152、A389的发酵液、上清液的絮凝效果较好,其中菌株A389的发酵液絮凝率为61.06%,上清液为67.92%。所有菌株菌悬液的絮凝率达到80%以上。菌株所产胞外聚合物表现出较好的絮凝效果,菌株RM-152所产胞外聚合物的絮凝率最高,达89.86%,其次是A389 (81.53%)。菌株A389所产胞外聚合物的产量最大,达12.53 g/L,具有广泛的盐度和pH适应性。【结论】乌勇布拉克干盐湖沉积物中蕴含丰富的可产生微生物絮凝剂的嗜盐古菌资源。嗜盐古菌菌株发酵液、上清液、菌悬液及胞外聚合物均具有良好的絮凝作用,尤其是胞外聚合物表现出较好的絮凝效果,具有广谱的盐度和pH耐受性。嗜盐古菌所产生物絮凝剂的发现对于后续高盐废水功能材料开发具有重要应用价值。     

Binding of phosphorylcholine to an IgM Waldenstr?m as studied by fluorescence spectroscopy and circular dichroism.

The binding characteristics of an IgM Waldenstr?m(FR) for the ligand phosphorylcholine has been studied by fluorescence spectroscopy. Upon phosphorylcholine addition, IgM FR exhibited 83% enhancement of the tryptophanyl fluorescence, which was associated with a red shift of the emission maximun (5nm). The same properties were observed with the 7S IgM subunits. The association constant KA for phosphorylcholine was 6X10(4) M-1 FOR IgM FR and the 7S subunit, as determined by fluorescence titration, a value in agreement with the obtained by equilibrium dialysis. No significant decrease in the KA value was found in the presence of 3 M urea; in 6 M urea, the increase in fluorescence intensity was 36% of the value obtained in the absence of denaturing agent. In contrast, only 4% of fluorescence enhancement was noted upon binding in 3 M GuHC1 and no enhancement could be seen when the concentration of GuHC1 was increased to 5 M, thus suggesting complete unfolding of the protein and subsequent loss of binding activity. The pH dependence study of the phosphorylcholine binding to IgM FR indicated no significant differences in the fluorescence enhancement between pH 5 and 8, whereas at more acidic or alkaline pH values, the enhancement became smaller. At pH 3.0 and 10.0, no enhancement was seen suggesting no binding of the ligand, a fact confirmed independently by equilibrium dialysis. When the spectroscopic properties of the IgM FR were compared with those of murine myeloma proteins that bind the same ligand large differences were recorded in the amplitude of the phosphorylcholine induced enhancement of the fluorescnece and in the shift of the emission maximum wavelength. This suggests that the human and murine proteins interact differently with the small ligand phosphorylcholine thus implying that the variable domains of these molecules are not identical     

应用细胞透性化技术快速提取氧化葡萄糖杆菌胞内右旋糖酐糊精酶

将细胞透性化技术应用到右旋糖酐酶的提取检测过程中,根据单因素实验和正交试验设计确定了从氧化葡萄糖杆菌(Gluconobacter oxydans)细胞中提取胞内右旋糖酐糊精酶(DDase)的最佳方法:甘氨酸(Gly)质量分数15%,Triton X-100体积分数1%,菌悬液OD600为0.5~6.0,pH为6.81,冰浴处理时间1 h,透性化试剂的提取效率可达到酶活最大值的90%以上。与超声波细胞破碎法相比,该方法条件温和,酶的释放率较高并易于大量试样的平行实验操作。     

Stability of some microginins synthesized by the cyanobacterium Woronichinia naegeliana (Unger) Elenkin

Microginins are linear oligopeptides synthesized by cyanobacteria. The literature data on their characteristics are scant. This study examined the influence of abiotic factors including pH, temperature, visible and ultraviolet radiation on the stability of the microginins FR3 (MG‐FR3), FR4 (MG‐FR4) and 757 (MG‐757) synthesized by Woronichinia naegeliana. In alkaline conditions (pH 9) only the concentration of MG‐757 was reduced significantly, by 14.3%. The tested microginins were stable at room temperature (half‐life 7–17 weeks). Boiling for one hour caused 26.1% decomposition of MG‐FR4 and 26.8% decomposition of MG‐757; MG‐FR3 was not significantly affected. Under visible radiation the initial content of MG‐FR4 declined 23.0%, but MG‐FR3 and MG‐757 proved insensitive to it. Treatment with a high dose of UV radiation (36 μmol m^?2 s^?1) caused the tested microginins to degrade by 13.8% to 21.4%. The study showed these microginins to be oligopeptides of high stability, the most stable of them being MG‐FR3.     

TG/DTG/DTA evaluation of flame retarded cotton fabrics and comparison to cone calorimeter data

Unbleached cotton fabrics (UCF) with 12.5% polypropylene scrim treated with two phosphate-urea based fire-retardant (FR) formulations were evaluated for FR properties using thermogravimetry/differential thermogravimetry/differential thermal analysis (TG/DTG/DTA) method. In addition to testing the two FR-treated unbleached cotton fabrics (CF-FR1 and CF-FR2), bleached cotton fabric (BCF) treated with the two FR formulations (BCF-FR1 and BCF-FR2) was evaluated. Both formulations were washable with add-on of FR chemicals at 18.7% (FR1) or 17.4% (FR2) for UCF and 22.5% (FR1) or 24.9% (FR2) for BCF. The decreasing order of sums at maximal rates of samples degradation in air environment according to DTG method was: BCF (21.40%/min)>UCF (12.91%/min)>BCF-FR2 (12.83%/min)>BCF-FR1 (11.68%/min)>CF-FR2 (10.20%/min)>CF-FR1 (9.73%/min). It indicates that both formulations cause the decrease of thermooxidation of the products at slower rates than the starting material. Several endo- and exothermic peaks observed by DTA in inert and oxidative environment gives additional information about the degradation process. The order of decreasing thermal responses of the studied samples based on sums of DTA peak values of endothermic and exothermic peaks in air environment is: UCF (0.597°C/mg)>BCF (0.120°C/mg)>CF-FR1 (0.089°C/mg)>BCF-FR1 (0.077°C/mg)>CF-FR2 (0.062°C/mg)>BCF-FR2 (0.053°C/mg). This is in agreement with the cone calorimeter results according to which the flammability properties are improving with the decreasing heat release rates or ignition time prolongation in order: UCF>CF-FR1>CF-FR2. The advantage of TG/DTG/DTA method is slower linear heating rate, which allows the more detailed evaluation of the light and flammable cotton fabric.     

Food restriction prevents the loss of isosafrole inducible cytochrome P-450 mRNA and enzyme levels in aging rats

The influence of food restriction (FR) on the drug-inducible capacity of liver microsomal cytochrome P-450s IA1, IA2 and IIB1 and IIB2 was studied in 20-month-old male Fischer-344 rats. ELISA and Western Blotting revealed that the induction of the cytochrome P-450-IA1/IA2 and P-450-IIB1/IIB2 enzymes was considerably higher in the liver microsomes of FR rats than in their ad libitum (AL) fed counterparts. In order to determine whether the higher P-450 enzyme levels in FR rats were a reflection of an increased synthesis rate or a stabilization of these enzymes, hybridization studies were performed with a cDNA probe for P-450-IIB1/IIB2. These studies show markedly higher levels of P-450-IIB1/IIB2 mRNAs in the livers of FR rats as compared to AL animals. These results suggest that it is possible to prevent the age-dependent loss of drug-induced cytochrome P-450s by 40% dietary restriction which suggest FR may improve the drug-metabolizing capacity during aging.     

Oxygen radical scavenging capacity of phenolic and non-phenolic compounds in red and white wines

The aim of the present study was the evaluation of the antioxidant content in phenolic and non-phenolic extracts of ten wine samples, trying to elucidate the potential role of unusual antioxidant compounds. Samples of wines processed from red and white grapes (Vitis vinifera L.), deprived of the volatile fraction at low temperature and buffered at physiological pH, were fractionated by C₁₈ into two fractions: FR1 and FR2. Non-phenolics, such as tartaric, malic, lactic, and succinic acids; glucose; fructose; and glycerin were mainly found in FR1, while polyphenols were present exclusively in FR2. Peroxyl radical quenching was assayed by the ORAC method, while superoxide and hydroxyl radical scavenging activity were assayed by electron paramagnetic resonance. In the ORAC and superoxide assays, most of the activity was found in FR2, while in hydroxyl radical assay, the activity was found in FR1. Model solutions were used to attribute a role to the single compounds in the evaluation of wine’s ROS scavenging capacity: the ORAC and superoxide anion scavenging effects were mainly attributed to the polyphenols, averaging 94.8%, with some contribution from glycerin, particularly in white wines. Unexpectedly, the main chemical responsible for hydroxyl radical scavenging activity was glycerin (56.1%), with the polyphenols scavenging at 18.1%.     

Design of small monomeric and highly bright near-infrared fluorescent proteins

Due to the low absorbance in the far-red (FR) and near-infrared (NIR) “optical window”, NIR fluorescent proteins (FPs) are powerful tools for deep imaging. Here, we report three new, highly bright NIR FPs termed BDFP1.8, BDFP1.8:1.8 (tandem BDFP1.8) and BDFP1.9, which evolved from a previously reported FR FP, BDFP1.6: a derivative of ApcF2 from Chroococcidiopsis thermalis sp. PCC7203. ApcF2 binds phycocyanobilin (PCB) non-covalently, while BDFPs, the derivatives of ApcF2, can bind biliverdin (BV) covalently. We identified that dimeric BDFP1.8 and monomeric BDFP1.8:1.8 have a 2.4-and 4.4-fold higher effective brightness, respectively, than iRFP720, which has the highest effective brightness among the reported NIR FPs. Monomeric DBFP1.9 (17 kDa) has one of the smallest masses among highly bright FPs in the FR and NIR regions. Enhancing the affinity between the apo-proteins and the BV chromophore is an effective method to improve the effective brightness of biliprotein FPs. Moreover, BDFP1.8 and 1.9 exhibit higher stability to temperature, pH and light than iRFP720. Finally, the highly bright NIR BDFP1.8 together with FR BDFP1.6 could effectively biolabel cells in dual colors.     

Structure-activity Relationship for FR901464: A Versatile Method for the Conversion and Preparation of Biologically Active Biotinylated Probes

The structure-activity relationship for FR901464, a potent cell-cycle inhibitor, was examined by synthesizing its analogs. A versatile method for converting FR901464 was devised. This method made it possible to synthesize biologically active FR901464-biotin conjugates which could be used to isolate the binding proteins.     

Structure-activity relationship for FR901464: a versatile method for the conversion and preparation of biologically active biotinylated probes

The structure-activity relationship for FR901464, a potent cell-cycle inhibitor, was examined by synthesizing its analogs. A versatile method for converting FR901464 was devised. This method made it possible to synthesize biologically active FR901464-biotin conjugates which could be used to isolate the binding proteins.     

Effects of dietary β-glucan and rice fermented on growth performance,fatty acids,and Newcastle disease immune response in turkey broilers

Poultry production has been developing in Vietnam with challenges of disease. Thus, feed additive should be investigated not only growth but also health enhancement. Here, we aimed to determine the effects of Saccharomyces cerevisiae-fermented rice (FR) and β-glucan on turkey’s growth performance, carcass characteristics, immune and fatty acid (FA) profiles. A total of 180 turkey chicks aged 1–56 days were randomly assigned to five sextuplicate groups and the birds had ad libitum feed and water access throughout the experiment. The five treatment groups were given the same diet with different proportions of FR and β-glucan. Broilers supplemented with 4% β-glucan and 4% FR presented the highest and second-highest growth performance, respectively. The 4% β-glucan and 4% FR treatments resulted in the highest carcass characteristic values without significantly affecting the breast or thigh meat pH or cooking loss. The 4% β-glucan and 4% FR treatments maximally increased the Newcastle disease (ND) antibody titers at 28, 42 and 56 days, respectively as well as thymus organ index. The foregoing treatments did not significantly affect the blood profiles relative to the control. However, the 4% FR treatment lowered the blood cholesterol levels (p > 0.05). The total FA profiles did not significantly differ among treatments. Nevertheless, both the β-glucan and FR treatments increased the MUFA levels compared to that of the control (p > 0.05). Hence, the dietary administration of 4% β-glucan and FR to turkey broilers could effectively improve their growth performance and immunity.