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对重组大肠杆菌JH16利用木糖产高纯度的三一乳酸进行研究。通过无氧管驯化EscherwhiacdiJH12菌株得到E.coliJH16,驯化后的菌株茵体浓度提高了31%,乙酸积累减少了43%;在摇瓶中考察不同Mg2+浓度对EcoliJHl6产三一乳酸的影响,确定最适Mg2+质量浓度为0.25g/L;EcoEJH16以60g/L木糖为C源,在7L全自动发酵罐中添加0.25g/LMg2+,乳酸积累量提高了18%,达38.18g/L,乳酸纯度高达95%;E.coliJH16在30g/L木糖和30g/L葡萄糖混合C源中,优先利用葡萄糖,当葡萄糖质量浓度低于1.56g/L后,菌体开始利用木糖进行乳酸发酵,最终得到39g/L乳酸。 相似文献
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以热带假丝酵母(Candida tropicalis)UP—3—24为出发菌株,经亚硝酸多次诱变,获得一株从正十七烷(nC17)生产十七碳二羧酸(Dc17,)的优良生产菌株NP—260。以20%(V/V)的nC17为碳源,摇瓶发酵4天,Dc17,达8 0 g/L以上。在16L自动控制罐上,不另加其乏生长碳源,加人总量30%(V/V)nC17,进行发酵试验,产酸高峰期,每升发酵液每小时能够产生1.8g的Dc17。其中产酸速率为每小时0.18%,24小时每开发酵液可增加40g以上的Dc17。发酵6天,Dc17高达133g/L以上,回收残烃后,对nC17的转化率为61.8%,后处理收率为77.6%.DC17的纯度为95.4%。 相似文献
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高产缬氨酸的北京棒杆菌(corynebacterium pekinense)突变株125菌株,在2.6L自控发酵罐上分批培养结果表明,当发酵中后期DO为零时,产酸量较多。也可用kL。值为指标来调节过程的供氧强度,Kla=90.75h-1时,产酸量最高。同时比较了恒速连续补加葡萄糖液,当F=3.75g/b时,产酸较高。由此获得了该菌株L一缅氨酸发酵的低供氧与恒速补糖的控制模式。总糖量为16.85%的发酵,可使产酸量达38.2g/L,转化率为22.67%。本文对有关试验结果,进行了发酵动力学的分析和讨论。 相似文献
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为了解除微生物发酵生产丙酸过程中代谢产物(丙酸)对菌体生长的抑制作用,以实验室保藏的产酸丙酸杆菌(耐30g/L丙酸)为出发菌株P-0,通过丙酸压力筛选获得了一株耐10g/L丙酸的产酸性能良好的菌株P-10,降低了发酵过程中丙酸对菌体生长的抑制作用。菌株P-10做摇瓶发酵,发酵周期168h,丙酸浓度为49.66g/L,产酸速率为0.30g/(L·h),较出发菌株P-0提高了53.04%;7L发酵罐实验表明,菌株P-10发酵周期168h,丙酸浓度为55.63g/L,产酸速率0.33g/(L·h)。同时对菌株P-10做二次接种实验,结果表明,84h为二次接种最适时间段,且84h进行二次接种时,丙酸浓度提高了17.77%,二次接种实验不但有利于有机酸的积累,而且可以提高菌株的产酸能力和耐酸能力;经过选育的菌株P-10具有优良的产酸稳定性,有利于菌种的工业化生产和应用,同时对后续的发酵分离耦合具有重要意义。 相似文献
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《中国生物工程杂志》2017,(11):83-88
为了解除微生物发酵生产丙酸过程中代谢产物(丙酸)对菌体生长的抑制作用,以实验室保藏的产酸丙酸杆菌(耐30g/L丙酸)为出发菌株P-0,通过丙酸压力筛选获得了一株耐10g/L丙酸的产酸性能良好的菌株P-10,降低了发酵过程中丙酸对菌体生长的抑制作用。菌株P-10做摇瓶发酵,发酵周期168h,丙酸浓度为49.66g/L,产酸速率为0.30g/(L·h),较出发菌株P-0提高了53.04%;7L发酵罐实验表明,菌株P-10发酵周期168h,丙酸浓度为55.63g/L,产酸速率0.33g/(L·h)。同时对菌株P-10做二次接种实验,结果表明,84h为二次接种最适时间段,且84h进行二次接种时,丙酸浓度提高了17.77%,二次接种实验不但有利于有机酸的积累,而且可以提高菌株的产酸能力和耐酸能力;经过选育的菌株P-10具有优良的产酸稳定性,有利于菌种的工业化生产和应用,同时对后续的发酵分离耦合具有重要意义。 相似文献
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目的:对海洋来源的具有产纤溶酶能力的枯草芽孢杆菌(Bacillus subtilis)LC6-1进行紫外诱变,得到高产且稳定的突变株PW6-3,对该突变株发酵产酶的条件进行优化。方法:采用单因素和正交试验进行发酵培养基组分和培养条件的优化。结果:突变株PW6-3的酶活力为(6 960.21 ± 85.51)U/mL,较原始菌株提高了30.48%。以PW6-3为出发菌株,采用单因素及正交试验的方法对菌株进行发酵培养基组分与培养条件优化,最终得到的最佳培养基组分是:玉米淀粉30 g/L,玉米浆干粉40 g/L,CaCl2 3 g/L;最佳发酵培养条件是:32℃,转速200 r/min,接种量3%,pH 6.5,种龄18 h,发酵培养时间66 h,最终菌株的酶活力稳定在(9 203.63 ± 67.85)U/mL。结论:发酵工艺优化后,菌株PW6-3纤溶酶产量较诱变之前的菌株LC6-1提高72.53%,且发酵工艺成本较低,具有较好的经济效益。 相似文献
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Michael Hesse 《Plant Systematics and Evolution》1980,134(3-4):229-267
Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout. 相似文献
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Surveillance of Class Ⅰ Newcastle Disease Virus at Live Bird Markets and Commercial Poultry Farms in Eastern China Reveals the Epidemic Characteristics 下载免费PDF全文
Xiaolong Lu Xiaoquan Wang Tiansong Zhan Yifan Sun Xin Wang Naiqing Xu Tianxing Liao Yu Chen Min Gu Shunlin Hu Xiaowen Liu Xiufan Liu 《中国病毒学》2021,36(4):818-822
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正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various 相似文献
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Altaf Hussain Tiantian Wu Hui Li Linjin Fan Kai Li Li Gao Yongqiang Wang Yulong Gao Changjun Liu Hongyu Cui Qing Pan Yanping Zhang Asim Aslam Khan Muti-Ur-Rehman Muhammad Munir Salman Latif Butt Xiaomei Wang Xiaole Qi 《中国病毒学》2019,34(1):102-105
<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV 相似文献
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Jiaming Li Yidun Zhang Lina Jiang Hongliang Cheng Jingjing Li Li Li Zehui Chen Fei Tang Yingying Fu Yifei Jin Bing Lu Jing Zheng Zhongyi Wang 《中国病毒学》2022,37(5):762-764
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1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference. 相似文献
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference. 相似文献
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Danrong Shi Keda Chen Xiangyun Lu Linfang Cheng Tianhao Weng Fumin Liu Nanping Wu Lanjuan Li Hangping Yao 《中国病毒学》2022,37(2):295-298
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1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID50 method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC50=0.12 IU/mL in Vero cells and EC50=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC50=0.25 IU/mL in Vero cells and EC50=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy. 相似文献
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID50 method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC50=0.12 IU/mL in Vero cells and EC50=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC50=0.25 IU/mL in Vero cells and EC50=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy. 相似文献
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Wenming Jiang Xin Yin Shuo Liu Shaobo Liang Cheng Peng Guangyu Hou Jinping Li Xiaohui Yu Yang Li Jingjing Wang Hualei Liu 《中国病毒学》2022,37(4):631-633
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1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection. 相似文献
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection. 相似文献