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1.
Chao LIU Xian ZHANG Zhi-ming RAO Ming-long SHAO Le-le ZHANG Dan WU Zheng-hong XU Hui LI 《Journal of Zhejiang University. Science. B》2015,(4):286-295
目的:获得一株高产雄甾-4-烯-3,17-二酮(AD)的Mycobacterium neoaurum突变株。创新点:获得了一株3-甾酮-Δ1-脱氢酶(KSDD)酶活缺陷型的高产AD的诱变菌株Mycobacterium neoaurum ZADF-4,并采用菌落显色法筛选KSDD酶活缺陷型M.neoaurum突变株。方法:(1)诱变方法:采用常压室温等离子体(ARTP)诱变技术来处理出发菌株M.neoaurum ZAD。ARTP诱变条件如下:功率40 W,气流量12.5 L/min,辐射距离1 cm,样品体积10μl,辐射时间为60、90、120、150和180 s;致死率统计优化后,最适辐射时间为150 s,致死率为90%~96%。(2)筛选方法:将ARTP诱变处理后的菌株点种在硝酸纤维滤膜上,30°C培养2 d,然后将长有菌落的滤膜小心取出并漂浮在4 mg/ml二氯靛酚(DCPIP)溶液(0.1 mmol/L磷酸缓冲液p H 7.0),30°C培养1 d直到全部菌落染成蓝色。然后将该滤膜取出,漂浮在250 mmol/L AD溶液(2%甲醇和50 mmol/L Tris p H 7.0缓冲液),室温放置15 min左右,观察菌落颜色变化。KSDD在底物AD存在时会脱氢产生雄甾-1,4-二烯-3,17-二酮(ADD)和H+,H+可以使被DCPIP染成蓝色的菌株褪色。因此,酶活缺陷型的菌株会仍保持蓝色,而酶活高的菌株会褪色为黄色(图3)。(3)对获得的潜在的高产AD菌株进行进一步的酶活检测以及产量验证,以期获得最优的突变株。结论:获得了4株具有潜在的高产AD能力的菌株,其中,最优的突变株ZADF-4的KSDD酶活相较于出发菌株ZAD下降了81.2%(图4),活性胶也证明其KSDD酶活相较于出发菌株下降明显(图5)。薄层色谱法(TLC)和高效液相色谱法(HPLC)实验证明突变株ZADF-4中,AD的产量有了明显的提高(图6和图7),提高到了(6.28±0.11)g/L,AD/ADD提高到8:1,AD的摩尔产率达到60.3%(表1)。对出发菌株ZAD和突变株ZADF-4的ksdd基因进行克隆和序列比对,发现ZADF-4的ksdd序列在5’端缺失9个核苷酸(atgttctac),导致3个氨基酸(MFY)的缺失;还发生了两个点突变,其中一个是无义突变(g.15a>6t),另一个是有义突变(g.413c>404t),并引起了相应位置上的氨基酸变化(p.138S>135L)。上述的基因突变及其引起的氨基酸序列的变化可能是引起M.neoaurum ZADF-4中KSDD酶活降低及AD产量提高的主要原因。 相似文献
2.
目的:通过从自然界中筛选和传统诱变育种相结合的方法,获得一株以玉米水解液为底物且能高效合成甲萘醌-7(MK-7)的芽孢杆菌突变菌株。创新点:首次在中国的发酵豆制品——豆豉中分离得到一株能以玉米水解液为底物合成MK-7的解淀粉芽孢杆菌Y-2(Bacillus amyloliquefaciens Y-2),并通过传统诱变育种获得一株带有二苯胺和结构类似物抗性的、以玉米水解液为底物的、高产MK-7的菌株B.amyloliquefaciens H.β.D.R.-5。方法:以来自中国不同省市地区的豆豉为分离样品,筛选高产纳豆激酶的菌株,再从中挑选出高产MK-7的菌株,并通过16S r DNA分析对其种属进行鉴定。采用常压室温等离子体(ARTP)系统,对分离到的高产MK-7菌株进行诱变处理,获得解除3-脱氧-D-阿拉伯庚酮糖-7-磷酸合成酶(即结构类似物抗性)和聚丙烯焦磷酸合成酶(即二苯胺抗性)反馈调节的菌株。最后,考察不同氮源、乙戊烯醇和镁离子(Mg~(2+)对突变菌株合成MK-7的影响,并分析在7 L发酵罐中合成MK-7的区别。结论:从中国豆豉中分离到了一株以玉米水解液为底物合成MK-7的菌株,经16S rD NA分析比对,鉴定为Bacillus amyloliquefaciens(图1)。通过比较MK-7产量,发现利用ARTP可以有效获得解除反馈调节作用的且高产MK-7的突变菌株H.β.D.R.-5(表1)。以大豆水解液和酵母水解液为氮源,异戊醇和MgSO_4有利于突变菌株H.β.D.R.-5合成MK-7(图2、表2和表3)。综上所述,利用ARTP处理从中国豆豉中分离到的以玉米水解液为底物的合成MK-7的菌株,可获得高产的MK-7菌株,该方法对选育工业化合成MK-7的菌株有重要参考价值。 相似文献
3.
本实验采用乳糖发酵短杆菌B_(27-12)作为出发菌株进行试验,首先,通过噬菌体敏感性试验,证明B_(27-12)对天津短杆菌T_(6-13)的五种噬菌体不敏感,从而证明B_(27-12)与T_(6-13)是不同噬菌体类型的谷氨酸生产菌。然后,将B_(27-12)用诱变效率高的原生质体诱变方法进行诱变选育,得到产酸较高的突变株,再进一步通过硫酸二酯(DES)和紫外线复合诱变法进行诱变,选育得到一株产酸较高的突变株D_(16)。 相似文献
4.
分别采用人工神经网络BP算法（网络结构为3-9-1）和线性回归分析方法对17个4-X-N-Y-6-氮杂雄-4-烯-3-酮衍生物在4℃时与小牛子宫雌激素受体的亲合力参数Iog1/K（iKi为衍生物对3BHSD的抑制常数）与分子的范德华体积V、最高被占据分子轨道能量EHOMO和9号碳原子的净电荷Q之间建立了QSAR模型,ANN模型的相关系数R=0.9999,标准偏差SD=0.0014。MLR模型的相关系数R=0.9470,标准偏差SD=0.4459。结果表明人工神经网络是一种比较精密的拟合方法,具有良好的预测效果。 相似文献
5.
庄莹 《闽西职业技术学院学报》2008,10(1):120-122
建立了高效液相色谱法测定克雷伯杆菌发酵甘油产物1,3-丙二醇(1,3-propanediol 1,3-PD)含量方法;应用紫外诱变法筛选耐高浓度甘油的高产1,3-PD的变异菌株,较佳的诱变条件为菌体诱变浓度为10-5稀释度,紫外照射时间为6min,经6轮诱变,筛选出了耐90g/L甘油的变异茼株,1,3-PD产量较原始菌株的提高了30%左右. 相似文献
6.
采用胶束电动毛细管色谱法（MEKC）分离8种3,4-二氢嘧啶-2-酮衍生物,研究了电泳缓冲液的pH值、组成及浓度和分离电压等对分离效果的影响。得到了优化的实验条件：缓冲溶液组成为10 mmol/LNa2HPO4-75 mmol/L十二烷基硫酸钠（SDS）-5 mmol/L脱氧胆酸钠（SDC）,pH=9.0,压力进样（3 447.4Pa）5 s,25℃,分离电压20 kV。8种分离物中其中6种分析物达到基线分离。 相似文献
7.
通过对突变株Bacillus subtilis spp.产β-葡聚糖酶的研究,得出其最佳培养基配方为（/100mL）：最佳培养基配方为（g/100ml）：大麦粉3.0,玉米粉2.0,豆粕粉4.0,MgSO40.03,CaCO30.05;在最佳培养基条件下进行摇瓶培养（35mL培养基/250mL三角瓶）,发酵液酶活力达56.53U/ml,是初始产酶条件的1.8倍。 相似文献
8.
目的：构建2,4,6-三硝基苯磺酸（2,4,6-trinitrobenzene sulfonic acid,TNBS）以及恶唑酮（oxazolone,OXZ）诱导的小鼠溃疡性结肠炎（ulcerative colitis,UC）模型。方法：120只昆明小鼠（）随机分为4组（n=30）。Ⅰ组、Ⅱ组参照Morris及Walter的方法制备小鼠TNBS模型：Ⅰ组（TNBS溶剂对照组）,50%乙醇0.1 m L灌肠;Ⅱ组（TNBS模型组）,0.6%TNBS溶液0.1 m L灌肠;两组灌肠给药一次后在d 1、d 2、d 3、d 5、d 7每组处死6只。Ⅲ组、Ⅳ组参照Heller方法制备小鼠OXZ模型：Ⅲ组（OXZ溶剂对照组）,皮肤涂抹100%乙醇0.1 m L,每天一次,连续2 d,d 7以50%乙醇0.1 m L灌肠;Ⅳ组（OXZ模型组）,皮肤涂抹1%OXZ溶液（100%乙醇溶解）0.1 m L每天一次,连续2 d（致敏）,d 7以0.5%OXZ（50%乙醇溶解）0.1 m L灌肠;两组灌肠给药一次后在d 1~d 5每天处死6只小鼠。观察Ⅰ~Ⅳ组小鼠疾病活动指数（disease activity index,DAI）、结肠组织大体损伤指数（colon macroscopic damage index,CMDI）和病理组织学评分（histopathological score,HPS）,并检测小鼠结肠组织中髓过氧化物酶（myeloperoxidase,MPO）、白细胞介素-4（interleukin-4,IL-4）、肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）的水平。结果：两种模型组小鼠DAI,CMDI和HPS均较对照组有明显改变;TNBS和OXZ诱导的结肠炎均可导致MPO明显上升,TNBS结肠炎TNF-α明显上升,OXZ结肠炎IL-4明显下降。结论：TNBS及OXZ均能诱导小鼠溃疡性结肠炎模型。两种模型各有特点,其中TNBS诱导的小鼠溃疡性结肠炎以辅助性T1（helper1,Th1）型炎症反应为主,OXZ诱导的小鼠溃疡性结肠炎以辅助性T2（helper2,Th2）型炎症反应为主。 相似文献
9.
《赣南师范学院学报》2022,(3):85-90
近年来灵菌红素由于其广泛的抗菌效果、免疫抑制活性及抗肿瘤活性得到广泛关注,实验室经过筛选和ARTP诱变得到一株灵菌红素产量较高的粘质沙雷氏菌菌株YW-3-10,在对YW-3-10发酵条件进行单因素实验的基础上在进行Box-Behnken中心组合试验和响应面分析,确定其摇瓶发酵产灵菌红素的最佳条件如下：甘油32 ml/L,胰蛋白胨17 g/L,甘氨酸1.5 g/L,NaCl 5 g/L,发酵温度28℃,转速200 rpm,装液量30 mL/250 mL,接种量4%,灵菌红素产量达3.285±0.0257 g/L,较初始条件灵菌红素产量有显著提升. 相似文献
10.
报道了显色剂1-（4-硝基苯基）-3-（甲基苯）-三氮烯化合物（NPMT）的合成及其与镉（Ⅱ）的显色反应.在非离子表面活性剂Triton X-100存在下,pH 11.0的Na2B4O7-NaOH的缓冲介质中,该试剂能与镉（Ⅱ）与发生显色反应,形成摩尔比为4∶1的橙黄色配合物,配合物在波长465 nm处有最大吸收峰,表观摩尔吸光系数ε为2.13×106 L·mol-1·cm-1,镉（Ⅱ）浓度在0.08-0.48μg/ml范围内遵守比尔定律.用拟定方法可有效测出不同废水中的镉（Ⅱ）. 相似文献
11.
通过对—二甲基—2—苯基—1,4—氧氮杂—5,7—二酮的研究,表明这一化合物及其衍生物是手性源化合物,利用它合成许多手性化合物同时找到了合成1,4—氧氮杂的方法,产率较高． 相似文献
12.
描述了一种基于TSMC 0.25 μm CMOS工艺设计的10 Gbit/s(STM-64,OC-192)四相位时钟1:4分接器.为了实现最高的工作频率和抑制共模噪声,所有的电路都采用了源极耦合逻辑(SCFL)结构.本分接器的特点是通过采用固定延时缓冲来实现四相位时钟和输出边沿的对准.通过在晶圆测试,该芯片在输入10 Gbit/s 长度为231-1伪随机码流时,分接功能正确.此时所测得的眼图的均方根抖动、上升沿和下降沿分别为11,123和137 ps.芯片面积为0.9 mm×1.2 mm,在3.3 V单电源供电的情况下的典型功耗为550 mW. 相似文献
13.
Yan ZHANG Wenjia ZHANG Min XIA Zhujun XIE Fangmei AN Qiang ZHAN Wenying TIAN Tianyue ZHU 《Journal of Zhejiang University. Science. B》2021,22(2):136
Objective:To investigate the relationship between the fatty acid-binding protein 4(FABP4)and colorectal cancer(CRC).Methods:Using an enzyme-linked immunosorbent assay(ELISA),we measured the expression of FABP4 in plasma of50 patients who underwent surgery for CRC from October 2017 to May 2018 and 50 healthy controls.The content of the visceral fat area(VFA)as seen with abdominal computed tomography(CT)scanning was measured by ImageJ software.The expression levels of FABP4,E-cadherin,and Snail proteins in CRC and adjacent tissues were determined by immunohistochemistry.Results:The mean concentration of plasma FABP4 of CRC patients was higher than that of the control group(22.46 vs.9.82 ng/m L;P<0.05).The concentration of plasma FABP4 was related to the tumor,node,metastatis(TNM)stage and lymph node metastasis and was independent of age,body mass index(BMI),tumor size and location,and the degree of differentiation of CRC.The concentration of plasma FABP4 was positively correlated with high VFA and lipoprotein-a(LPA)(P<0.05);but it was not correlated with total cholesterol(TG),total triglyceride(TC),low-density lipoprotein(LDL),high-density lipoprotein(HDL),or apolipoprotein AI(Apo-AI).The expression of FABP4 protein in CRC tissues was positively correlated with the degree of CRC differentiation,tumor stage,and lymph node metastasis.The level of FABP4 protein was negatively correlated with E-cadherin protein(r=-0.3292,P=0.0196)and positively correlated with Snail protein(r=0.5856,P<0.0001).Conclusions:High LPA and VFA were risk factors for increased plasma FABP4 in CRC patients.FABP4 protein was highly expressed in CRC tissues and associated with TNM stage,differentiation,and lymph node metastasis of CRC.The level of FABP4 in CRC tissue was correlated with E-cadherin and Snail expression,suggesting that FABP4 may promote CRC progression related to epithelial-mesenchymal transition(EMT). 相似文献
14.
采用液相沉淀法制取了Cs2（HSO4）2（H2PO4）,用XRD,IR标明其晶体结构。通过研究发现SO42-：PO43-=0.7：0.3时能够制得结晶良好的Cs3（HSO4）2（H2PO4）晶体,其电导率σ为2.52×10-3S/cm。 相似文献
15.
Motion estimation is an important part of the MPEG-4 encoder, due to its significant impact on the bit rate and the output quality of the encoder sequence. Unfortunately this feature takes a significant part of the encoding time especially when the straightforward full search(FS) algorithm is used. In this paper, a new algo-rithm named diamond block based gradient descent search (DBBGDS) algorithm, which is significantly faster than FS and gives similar quality of the output sequence, is proposed. At the same time, some other algo-rithms, such as three step search (TSS), improved three step search (ITSS), new three step search (NTSS),four step search (4SS) , cellular search (CS) , diamond search (DS) and block based gradient descent search (BBGDS) , are adopted and compared with DBBGDS. As the experimental results show, DBBGDS has its own advantages. Although DS has been adopted by the MPEG-4 VM, its output sequence quality is worse than that of the proposed algorithm while its complexity is similar to the proposed one. Compared with BBGDS, the proposed algorithm can achieve a better output quality. 相似文献
16.
The degradation characteristic of 4-bromdiphenyl ether （BDE-4） was investigated in different solutions.The study indicates that the process of direct degradation of this compound is dependent upon the bromine and the ether bond connected to diphenyl by electron beam.laser flash photolysis was employed to determine the degradation of each species （cationic,neutral,and anionic）.From these data,intermediate products of BDE-4 degradation were shown for direct irradiationdegradation.The neutral radical was formed during the photolysis of these compounds.For all the compounds,diphenyl ether and hydroxybiphenyl were observed as common products.Reaction of the BDE-4 under electron beam was debromide.The debromide rate of BDE-4 at pH=5.5 is somewhat lower than that of BDE-4 at pH=10.0.The decomposition rate for BDE-4 is 99.8% at pH=10.0 on the dose of 14 kGy.BDE-4 from its radical could provide bromine ion into water and the cation radical of BDE-4 formed quickly recombine with hydrogen radical and formed phenyl ether. 相似文献
17.
INTRODUCTIONAfterthedepositionofMunicipalSolidWaste(MSW) ,thebiodegradableorganicfractionun dergoesaseriesofchemicalandbiochemicaldegradation .Basedontheanalysisoftheemit tedgases,fivedistinctphasesofthelandfillanaerobicdegradationprocess,(i.e.,initialadj… 相似文献
18.
Methane (CH4) is an important greenhouse gas and a major environmental pollutant, second only to carbon dioxide (CO2) in its contribution to potential global warming. In many cases, methane emission from landfills otherwise emitted to the atmosphere can be removed and utilized, or significantly reduced in quantity by using cost-effective management methods. The gas can also be used as a residential, commercial, or industrial fuel. Therefore, emission reduction strategies have the potential to become low cost, or even profitable. The annual growth rate of Municipal Solid Waste (MSW) output in China is 6.24%, with the highest levels found in South China, Southwest China and East China. Cities and towns are developing quickly in these regions. MSW output was only 76.36 Mt in 1991 and increased to 109.82 Mt in 1997, registering an average increase of 43.8%. In China, methane emission from landfills also increased from 5.88 Mt in 1991 to 8.46 Mt in 1997; so the recovery of methane from landfills is a profitable project. 相似文献
19.
Zr-4管收缩系数在工业应用中有重要意义,本文通过测量Zr-4管的收缩系数,对CSR的测量原理及方法进行了探讨。对其他金属管材可作参考使用。 相似文献
20.
杨琼 《雁北师范学院学报》2000,(3)
报道了在多聚磷酸（PPA）中将醚酰化的方法,合成了4'─乙酰基苯并15冠5,以此为原料,在酸性条仟下与氨基脲作用,合成了4'乙酰基缩氨脲基苯并15冠5．经由IR、MS和元素分析仪对合成的两种新物质的结构进行了鉴定． 相似文献