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研究三元能量、紫外线（ＵＶ）、硫酸二乙酯（ＤＥＳ）、吖啶橙（ＡＯ）、ＤＥＳ＋ＵＶ＋ＡＯ复合处理对妥布拉霉素产生菌－黑暗链霉素（ＴＯＢ）的诱变作用。从１５００株正突变株中筛选出产高性能最佳的菌株为ＱＢ＋１３０－Ｓ４。发酵单位提高了８５．１２％,主组份含量由４１．２５％提高到５６．０８％。三元能量用于ＴＯＢ菌种诱变不仅提高了产抗水平,而且菌株生长时间缩短,经４次传代,高产菌的遗传性能稳定。三元能量应用 相似文献
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N+离子注入选育色素产生菌Monascus的研究 总被引：4，自引：0，他引：4
应用10 keV的N+离子注入,对产红色素红曲菌进行了诱变选育.在确定最佳注入剂量后,经过两轮离子注入诱变筛选,选育出1株高产突变株,红色素色价提高38.1%,且色调适宜.经传代培养,其高产性状能稳定遗传.对该菌株的发酵特性也进行了研究. 相似文献
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低能N+离子注入谷氨酸产生菌诱变选育及其发酵的研究 总被引：3，自引：0，他引：3
采用低能N 离子注入技术,以D1 1 0 和D1 1 0B为出发菌进行了诱变选育高产谷氨酸菌株和发酵的试验研究。通过研究已经初筛到两株高产菌株D52 2 1 和B32 63,其多批次摇瓶平均产酸分别达到 8.4%、7.5 %,比出发菌分别提高 3 5.48%和 2 5 %.其一级种子生长曲线比原出发菌有明显变化,高产菌株发酵对数期平均提前 2～ 3h.从发酵曲线显示出高产菌株的代谢活力增强,倍增时间缩短,对缩短发酵周期有积极的促进作用 相似文献
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氧化镧对Cu—O／γ—Al2O3催化剂活性和结构的影响 总被引：1，自引：0，他引：1
在色谱－微反流动法实验装置上考察了三种催化剂对ＣＯ和ＣＨ４的氧化活性，并运用ＢＥＴ、ＸＲＤ及ＴＰＲ等技术研究了Ｌａ２Ｏ３的添加对Ｃｕ－Ｏ／γ－Ａｌ２Ｏ３催化剂性能及催化剂氧化还原特性的影响．结果表明，Ｌａ２Ｏ３的添加不仅使Ｌａ２Ｏ３与ＣｕＯ之间产生相互作用，且也与载体γ－Ａｌ２Ｏ３产生相互作用；Ｌａ２Ｏ３的添加促进了ＣｕＯ在γ－Ａｌ２Ｏ３上的分散，并使ＣｕＯ均以非晶相形式存在，从而改善了Ｃｕ－Ｏ／γ－Ａｌ２Ｏ３催化剂对ＣＯ和ＣＨ４的氧化活性，还使Ｌａ－Ｃｕ－Ｏ／γ－Ａｌ２Ｏ３催化剂的ＴＰＲ峰温降低了７５℃． 相似文献
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茶多酚抗突变和消除自由基作用的研究 总被引：6，自引：0，他引：6
采用Ｅ．ＣｏｌｉＳＯＳ显色法，小鼠骨髓细胞微核及染色体畸变试验和体外自由基消除实验等方法测定了茶多酚复合物（ＴＰ）的抗突变和消除自由基作用．结果表明：（１）ＴＰ的终浓度在２．５和５ｍｇ／ｍｌ时，对由阳性致突变物ＭＮＮＧ，ＥＭＳ和ＮａＮ＿３诱导的ＳＯＳ应答反应均具有明显的抑制作用；（２）小鼠每日ｉｇ４０、８０和１２０ｍｇ／ｋｇ剂量的ＴＰ能明显抑制由环磷酰胺（ＣＰ）诱发的骨髓ＰＣＥ的ＭＮＣＦ，三种剂量ＴＰ的抑制率分别为４０．９８％、６６．７６％和６５．９４％；（３）ＴＰ对ＭＭＣ诱发的骨髓细胞染色体畸变（ＣＡ）的抑制率分别为６２．５６％、５５．７１％和４７．９５％；（４）在Ｘ／ＸＯ－ＥＳＲ、Ｘ／ＸＯ／Ｌｕｍｉｎｏｌ－ＢＣＬ和ＩＲ／ＮＢＴ－ＳＰＭ三种模型中ＴＰ对超氧阴离子Ｏ＿２自由基均具有极强的消除作用，消除率分别为９８±６％、９８±１．２％和９５±１．５％，对Ｏ＿２的消除效率明显强于维生素Ｃ和Ｅ，对不同工艺制备的ＴＰ消除活性氧自由基作用的测定结果显示：脱咖啡碱程度高，ＥＧＣ和Ｌ－ＥＧＣＧ含量比例高的ＴＰ－３制剂消除Ｏ＿２的效率最高．因此，ＴＰ消除有害自由基，中断或终止自由基的氧化反应是抗突变，抗肿瘤作用的主要机制 相似文献
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纤维素分解菌的分离、筛选及其环境适应性初步研究 总被引：14，自引：0，他引：14
以滤纸平板和羧甲基纤维素钠培养基为基础培养基,从采集的样品中筛选出具有分解纤维素能力的38株菌株。采用纤维素刚果红培养基进行粗选,得到10株透明圈较大的菌株。将这10株菌株进行液体发酵培养,测定其酶活力,得到4株分解纤维素能力较强的菌株。对这4株菌株进行碳源、温度、pH值的适应性研究。结果发现,真菌3和真菌6的适应性都比较好。 相似文献
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报道了用长爪沙鼠从流行性出血热病人血液中直接分离到5株病毒,经直接荧光血清、单克隆抗体分型血清及电镜观察等鉴定,确定1株为家鼠型流行性出血热病毒,其余4株为野鼠型流行性出血热病毒。 相似文献
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《Electronic Journal of Biotechnology》2014,17(5):246-249
BackgroundThe selection of new yeast strains could lead to improvements in bioethanol production. Here, we have studied the fermentative capacity of different auxotrophic mutants of Saccharomyces cerevisiae, which are routinely used as hosts for the production of heterologous proteins. It has recently been found that these strains exhibit physiological alterations and peculiar sensitivities with respect to the parental prototrophic strains from which they derive. In this work the performance of auxotrophic S. cerevisiae CEN.PK strains was compared to the corresponding prototrophic strain, to S. cerevisiae T5bV, a strain isolated from grape must and to another auxotrophic strain, S. cerevisiae BY4741.ResultsThe results indicate that the fermentative capacity of strains grown in 2% glucose was similar in all the strains tested. However, in 15% initial glucose, the auxotrophic strains exhibited a more than doubled ethanol yield on biomass (10 g g- 1dw) compared to the prototrophic strains (less than 5 g g- 1dw). Other tests have also evidenced that in medium depletion conditions, ethanol production continues after growth arrest.ConclusionsThe results highlight the capacity of auxotrophic yeast strains to produce ethanol per mass unit, in a higher amount with respect to the prototrophic ones. This leads to potential applications for auxotrophic strains of S. cerevisiae in the production of ethanol in both homogeneous and heterogeneous phases (immobilized systems). The higher ethanol yield on biomass would be advantageous in immobilized cell systems, as a reduced yeast biomass could greatly reduce the mass transfer limitations through the immobilization matrix. 相似文献
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A new incremental theory has been developed for solving the problem of partially yielded thick-walled cylinders. Incremental stresses and strains are directly used as variables, hence numerical differentiation in the evaluation of stresses and strains is not required. The stresses and strains in all principal directions can be computed at the same time from governing equations for each increment of loading. Since the consideration of loading history is involved, the present theory is particularly suitable for predicting stress and strain distribution of a thick-walled cylinder subjected to nonproportionate loading. 相似文献
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P. Sharma M. Bose Isa Mohd S. Bagdi H. G. Raj 《Indian journal of clinical biochemistry : IJCB》2000,15(2):83-87
Genomic DNA from a clinical isolate ofMycobacterium avium-intracellulare complex was purified and cloned in PBR 322 at the tetracycline resistance site using Bam HI restriction enzyme. A 16 kb cloned
fragment was purified, radiolabeled and used as a probe. Genomic DNA isolated from nineteen MAC strains, threeM. tuberculosis strains and oneM. kansasii strain were digested with Eco RI restriction enzyme, Southern blotted and hybridized with the 16 kb cloned and labeled fragment.
Twelve MAC strains showed positive hybridization although five strains gave faint signals. Positive hybridization was noted
in two out of the threeM. tuberculosis strains, possibly due to shared DNA homology. No signal was received from the singleM. kansasii strain used in this study. 相似文献
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BackgroundWe aimed to test the possibility of improving polypeptide production from soybean meal fermentation by engineered Aspergillus oryzae strains. Four different protease genes were cloned and transformed into wild-type A. oryzae, and the engineered A. oryzae strains were then used for soybean meal fermentation.ResultsThe results showed different degrees of improvement in the protease activity of the four transformants when compared with wild-type A. oryzae. A major improvement in the polypeptide yield was achieved when these strains were used in soybean meal fermentation. The polypeptide conversion rate of one of the four transformants, A. oryzae pep, reached 35.9%, which was approximately twofold higher than that exhibited by wild-type A. oryzae. Amino acid content analysis showed that the essential amino acid content and amino acid composition of the fermentation product significantly improved when engineered A. oryzae strains were used for soybean meal fermentation.ConclusionsThese findings suggest that cloning of microbial protease genes with good physicochemical properties and expressing them in an ideal host such as A. oryzae is a novel strategy to enhance the value of soybean meal. 相似文献
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介绍了头孢噻肟、头孢哌酮,拉他霉素、头孢三嗪及头孢他定等第三代头孢菌素在治疗伤寒方面的药理学优势和临床应用的进展.第三代头孢菌素治疗伤寒的主要要应症为:(1)多重耐药伤寒曹株引起的严重感染;(2)并发脑膜炎、骨髓炎、肺炎等;(3)伴有免疫缺陷或中性粒细胞减少的患者;(4)伴有肾功能不全的患者;(5)婴儿、儿童和孕产妇患者.对于多重耐药菌株所致的重症伤寒,第三代头孢菌素尚可与另一种有协同作用的抗生素联合用药. 相似文献