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乳杆菌发酵烟梗制备生物塑料前体物L-乳酸的研究 被引量:6
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作者 朱大恒 张可可 +6 位作者 陈彦好 张向磊 何莹龙 王姣 杨增光 张磊 席宇 《烟草科技》 EI CAS 北大核心 2014年第8期78-81,共4页
为资源化利用废弃烟梗,从甘薯淀粉加工废水中分离到1株L-乳酸产生菌XJL,并对XJL培养特性、形态特征及生理生化特性进行了检测,同时结合其16S rDNA基因序列同源性分析,初步鉴定为干酪乳杆菌(Lactobacillus casei,L.casei)。XJL能够发酵... 为资源化利用废弃烟梗,从甘薯淀粉加工废水中分离到1株L-乳酸产生菌XJL,并对XJL培养特性、形态特征及生理生化特性进行了检测,同时结合其16S rDNA基因序列同源性分析,初步鉴定为干酪乳杆菌(Lactobacillus casei,L.casei)。XJL能够发酵废弃烟梗提取液(Tobacco stem extraction,TSE)产生L-乳酸。在装载量100 mL/150 mL、接种量7.5%、35℃条件下静置培养48 h,废弃烟梗发酵产L-乳酸的最高值为143 g/kg。 展开更多
关键词 烟梗 生物塑料 L-乳酸 乳杆菌 分离 鉴定
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酸性离子液体催化乙酰丙酸自缩合制备生物燃料前体 被引量:1
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作者 杨烨 史雅玫 +2 位作者 安华良 赵新强 王延吉 《精细石油化工》 CAS 北大核心 2020年第4期30-36,共7页
制备了两种磺酸功能化离子液体和两种羧酸功能化离子液体用于催化乙酰丙酸羟醛自缩合反应。利用红外光谱、酸碱滴定及Hammett指示剂与紫外-可见吸收光谱联用技术,对其结构、酸量及酸强度进行了分析,并评价了其催化性能。结果表明,离子... 制备了两种磺酸功能化离子液体和两种羧酸功能化离子液体用于催化乙酰丙酸羟醛自缩合反应。利用红外光谱、酸碱滴定及Hammett指示剂与紫外-可见吸收光谱联用技术,对其结构、酸量及酸强度进行了分析,并评价了其催化性能。结果表明,离子液体的酸强度与乙酰丙酸转化率呈正相关,与航空煤油前体C9~C16收率呈负相关;羧酸功能化离子液体N,N,N-三乙基-N-羧甲基四氟硼酸铵([c-m-N(Et)3]BF4)有利于C9~C16产物的生成。以[c-m-N(Et)3]BF4为催化剂,考察了溶剂种类和反应条件对乙酰丙酸羟醛自缩合反应的影响。在乙酰丙酸3 g、溶剂乙醚用量27 mL、催化剂用量10%、反应温度130℃和反应时间6 h的条件下,乙酰丙酸转化率为49.1%,产物C5~C8、C9~C16和C17~C21的收率分别为7.4%、16.8%和24.7%。[c-m-N(Et)3]BF4重复使用4次,其结构和催化性能基本不变。 展开更多
关键词 生物质转化 乙酰丙酸 羟醛自缩合反应 酸性离子液 生物燃料
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淀粉样β蛋白前体蛋白17肽对神经保护的作用及其机制 被引量:1
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作者 姚洁 《中国临床康复》 CSCD 北大核心 2006年第22期131-133,共3页
目的:探讨淀粉样β蛋白前体蛋白17肽对神经保护的作用机制,为阿尔茨海默病的治疗提供理论依据。资料来源:应用计算机检索Medline1987/2003关于淀粉样b蛋白前体蛋白研究的文章,检索词为“amyloidprecursorprotein,Alzheimer’sdisease”... 目的:探讨淀粉样β蛋白前体蛋白17肽对神经保护的作用机制,为阿尔茨海默病的治疗提供理论依据。资料来源:应用计算机检索Medline1987/2003关于淀粉样b蛋白前体蛋白研究的文章,检索词为“amyloidprecursorprotein,Alzheimer’sdisease”等,限定文章语言种类为英文;同时检索中国期刊网1999/2004期间的相关文献,检索词为“淀粉样β蛋白前体蛋白,阿尔茨海默病”,限定文章语言种类为中文。并手工查阅相关书籍。资料选择:对资料进行初审,选择与淀粉样β蛋白前体蛋白和阿尔茨海默病相关的研究论著,排除重复的同一研究。资料提炼:共收集到29篇相关文献,其中中文文献12篇,英文文献17篇。资料综合:淀粉样β蛋白前体蛋白17肽无论体内实验还是体外实验均显示对神经细胞的保护作用,它通过上调其他神经营养因子的表达,促进神经细胞存活信号通路相关蛋白的表达,抑制神经细胞凋亡因子的表达,影响神经细胞蛋白质代谢,从而改善模型动物神经系统超微结构的损害,提高模型动物学习记忆能力,达到神经保护的作用。结论:促进神经营养因子的表达是淀粉样β蛋白前体蛋白17肽神经元保护作用的有效机制之一;淀粉样β蛋白前体蛋白17肽对神经细胞存活信号通路的各个步骤均有影响,可以促进细胞存活是淀粉样β蛋白前体蛋白17肽神经元保护作用的另一有效机制。 展开更多
关键词 淀粉样β蛋白/生物合成 肽类 神经元
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雷帕霉素及其衍生物开发现状、作用机制及生物合成研究进展 被引量:7
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作者 李进 邹祥 《中国抗生素杂志》 CAS CSCD 北大核心 2011年第11期806-813,共8页
目的介绍了近年来雷帕霉素及其衍生物的开发现状、作用机制与生物合成途径,探讨了通过前体定向生物合成与诱变生物合成的方式,获得雷帕霉素衍生物的研究进展,展望了雷帕霉素及衍生物的研究前景。方法分析、归纳、总结近年来发表的相关... 目的介绍了近年来雷帕霉素及其衍生物的开发现状、作用机制与生物合成途径,探讨了通过前体定向生物合成与诱变生物合成的方式,获得雷帕霉素衍生物的研究进展,展望了雷帕霉素及衍生物的研究前景。方法分析、归纳、总结近年来发表的相关文献。结果与结论雷帕霉素及其衍生物是新型强效的免疫抑制剂与抗肿瘤药物,具有抗真菌、抗增殖及潜在延长哺乳动物寿命周期等作用。采用前体定向生物合成、诱变生物合成与组合生物合成的方式,可快速获得其具药理活性的衍生物。基于生物合成途径,采用系统生物学相关手段可获高产工程化菌种应用于工业化生产。 展开更多
关键词 雷帕霉素 MTOR 生物合成 定向生物合成 诱变生物合成
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南、北方坛紫菜多糖结构特征的比较研究 被引量:9
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作者 高洪峰 纪明侯 曹文达 《海洋与湖沼》 CAS CSCD 北大核心 1992年第5期541-549,共9页
对南方产(1987年3月采)和移植北方养殖(1988年11月采)的两种坛紫菜的热水和冷水提取多糖进行了层析分级,用^(13)C-NMR和IR光谱研究了各级分的化学结构特征,结果表明,南北方坛紫菜多糖分别主要由用 1.0mol/L和0.5mol/L NaCl从DEAE—Sepha... 对南方产(1987年3月采)和移植北方养殖(1988年11月采)的两种坛紫菜的热水和冷水提取多糖进行了层析分级,用^(13)C-NMR和IR光谱研究了各级分的化学结构特征,结果表明,南北方坛紫菜多糖分别主要由用 1.0mol/L和0.5mol/L NaCl从DEAE—Sephadex A_(50)层析柱洗脱下的带电荷的琼胶糖分子组成;^(13)C-NMR谱图表明坛紫菜主要由琼胶糖结构及其生物前体(硫酸基结合在L-半乳糖的第6位碳上)构成,且甲基化琼胶糖在南方坛紫菜中的含量明显比北移坛紫菜高,这是坛紫菜由南方移植北方后的明显差异。 展开更多
关键词 坛紫菜 琼胶糖 生物前体 结构 紫菜
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Highly efficient Nb2O5 catalyst for aldol condensation of biomass-derived carbonyl molecules to fuel precursors 被引量:3
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作者 Yaxuan Jing Yu Xin +2 位作者 Yong Guo Xiaohui Liu Yanqin Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第8期1168-1177,共10页
Aldol condensation is of significant importance for the production of fuel precursors from biomass- derived chemicals and has received increasing attention. Here we report a Nb2O5 catalyst with excellent activity and ... Aldol condensation is of significant importance for the production of fuel precursors from biomass- derived chemicals and has received increasing attention. Here we report a Nb2O5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb2O5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO2 and Al2O3), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium- aluminum hydrotalcite). The detailed characterizations by N2 sorption/desorption, NH3-TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb2O5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb2O5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb2O5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation. 展开更多
关键词 Aldol condensation NB2O5 C=O activation Fuel precursor Bio-liquid alkane One-pot process
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Improvement of the riboflavin production by engineering the precursor biosynthesis pathways in Escherichia coli 被引量:3
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作者 徐志博 林振泉 +1 位作者 王智文 陈涛 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第11期1834-1839,共6页
3,4-Dihydroxy-2-butanone 4-phosphate (DHBP) and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and... 3,4-Dihydroxy-2-butanone 4-phosphate (DHBP) and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and engineering purine pathway in a riboflavin-producing Escherichia colt strain. Initially, ribB gene was overexpressed to increase the flux from ribulose 5-phosphate (Ru-5-P) to DHBP. Then ndk and grnk genes were overexpressed to enhance GTP supply. Subsequently, a R419L mutation was introduced into purA to reduce the flux from IMP to AMP. Finally, co-overexpression of mutant purF and prs genes further increased riboflavin production. The final strain RF18S produced 387.6 mg riboflavin · L-1 with a yield of 44.8 mg riboflavin per gram glucose in shake-flask fermentations. The final titer and yield were 72.2% and 55.6% higher than those of RF01S, respectively. It was concluded that simultaneously engineering the DHBP synthase and GTP biosynthetic pathway by rational metabolic engineering can efficiently boost riboflavin production in E. coll. 展开更多
关键词 Escherichia coilRiboflavin3A-Dihydroxy-2-butanone 4-phosphatesynthasePurine pathwayGTPMetabolic engineering
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Relationship between Mutations in DNA Sequences Loci Coding Pre-miRNAs and Genes Related to Biogenesis of SncRNAs with MiRNA Expression in Endometrial Carcinoma Tissues
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作者 Massimiliano Chetta Angela Cordella +3 位作者 Giuseppina Bruno Maurizio Guida Alessandro Weisz Maria Ravo 《Journal of Environmental Science and Engineering(B)》 2015年第7期372-379,共8页
Endometrial cancer (EC) is the most common and lethal gynaecological cancer type in Europe and in North America. Frequently EC arises more in the corpus proper and manifests as round, polypoid expansile masses, but ... Endometrial cancer (EC) is the most common and lethal gynaecological cancer type in Europe and in North America. Frequently EC arises more in the corpus proper and manifests as round, polypoid expansile masses, but it may also originate in the lower uterine segment or spread in endometrium with necrosis and hemorrhage. The analysis was performed using a custom panel containing all DNA sequences loci coding pre-miRNAs and genes related to biogenesis and regulation of sncRNAs in normal and tumor tissues extracted from 6 unrelated patients with endometrial carcinoma. The identified variations were correlated with mature miRNAs differentially expressed in the same normal and tumor endometrial tissues. The comparison analysis confirmed the high degree of cellular and genetic intratumoral heterogeneity with a temporal and spatial miRNA expression distribution in association with genomic variants identified. The classification of specific DNA mutations, onto the loci identified, should be suitable to characterize possible instability genome regions and help classification of tumors to ameliorate the clinical management of patients affected by endometrial carcinoma. 展开更多
关键词 Endometrial cancer pre-miRNAs sncRNA miRNA expression.
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炎症性肠病生物检测器的构建与调试 被引量:2
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作者 郭炜航 李帛轩 +3 位作者 周浩宇 张辰 王宣 倪川 《生物工程学报》 CAS CSCD 北大核心 2018年第12期1906-1914,共9页
利用工程改造过的肠道微生物进行无创、便宜便捷的肠道炎症检测、治疗可有效应用于医药行业。肠道炎症通常伴随着肠道中硫代硫酸盐和连四硫酸盐的增加,双组分系统ThsSR和TtrSR是两套分别检测这两种小分子的生物感受器系统。采用荧光蛋... 利用工程改造过的肠道微生物进行无创、便宜便捷的肠道炎症检测、治疗可有效应用于医药行业。肠道炎症通常伴随着肠道中硫代硫酸盐和连四硫酸盐的增加,双组分系统ThsSR和TtrSR是两套分别检测这两种小分子的生物感受器系统。采用荧光蛋白作为指示剂需要复杂的测试仪器,不适用于家用检测环境,而肉眼可见的色素蛋白和有色小分子作为指示剂将可能扩大ThsSR和TtrSR的应用前景。两套系统分别被转入大肠杆菌EscherichiacoliTop10和益生菌E. coli Nissle 1917中,sfGFP信号表达效果证明了这两套系统可用。考虑实际应用,sfGFP被一系列色素蛋白和显色小分子替换,在E. coli Top10中,一系列色素蛋白和紫色杆菌素前体protoviolaceinic acid的显色效果明显,表明了该系统具有用于实际肠道炎症检测的可行性。结果表明,改进后的ThsSR和TtrSR系统能够针对不同浓度的肠道炎症标记物作出相应程度的反应,具备用于家庭环境人体肠道炎症检测的潜力。 展开更多
关键词 炎症性肠病 硫代硫酸盐 连四硫酸盐 生物检测器 色素蛋白 紫色杆菌素
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The application of immunoassay in bioanalysis 被引量:3
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作者 牟玲丽 李三望 +2 位作者 周瑞 唐芳 余鹏 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2015年第4期205-216,共12页
Immunoassay technology is an analytical method with high sensitivity and specificity; it provides a technique to assay materials which cannot be measured by other methods, or are difficult to detect. It plays a very i... Immunoassay technology is an analytical method with high sensitivity and specificity; it provides a technique to assay materials which cannot be measured by other methods, or are difficult to detect. It plays a very important role in biological sample pre-treatment, therapeutic drug monitoring and drug determination, and is one of the important means for in vivo drug analyses. This paper reviews immunoassays commonly used in bioanalysis, including immunoextraction and immunodepletion for pretreatment of biological samples, conventional immunoassay methods and new immunoassay technologies for determination of target drugs. 展开更多
关键词 Immunoassay Sample pretreatment Biological samples Bioanalysis
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硫肽类抗生素类似物合成进展 被引量:1
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作者 王守锋 郑庆飞 +1 位作者 段盼盼 刘文 《有机化学》 SCIE CAS CSCD 北大核心 2017年第7期1653-1666,共14页
硫肽类抗生素是一类富含硫元素且被高度修饰的聚噻(噁)唑多肽类天然产物,该家族化合物以其复杂的分子结构、良好的生物活性以及新颖的抗菌作用模式而成为研究热点.近年来,对于硫肽类抗生素类似物的合成研究发展迅速.综述了通过化学半合... 硫肽类抗生素是一类富含硫元素且被高度修饰的聚噻(噁)唑多肽类天然产物,该家族化合物以其复杂的分子结构、良好的生物活性以及新颖的抗菌作用模式而成为研究热点.近年来,对于硫肽类抗生素类似物的合成研究发展迅速.综述了通过化学半合成、组合生物合成以及前体导向突变生物合成方法获得的硫肽类抗生素类似物的研究进展. 展开更多
关键词 硫肽类抗生素类似物 化学半合成 组合生物合成 导向突变生物合成
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Anatomical and biomechanical study on the interosseous membrane of the cadaveric forearm 被引量:1
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作者 YI Xian-hong PAN Jun GUO Xiao-shan 《Chinese Journal of Traumatology》 CAS 2011年第3期147-150,共4页
Objective: To study the anatomical and biomechanical features of the interosseous membrane 0OM) of the cadaveric forearm. Methods: Ten radius-IOM-ulna structures were harvested from fresh-frozen cadavers to measur... Objective: To study the anatomical and biomechanical features of the interosseous membrane 0OM) of the cadaveric forearm. Methods: Ten radius-IOM-ulna structures were harvested from fresh-frozen cadavers to measure the length, width and thickness of the tendinous portion oflOM. Then, the tendinous portion was isolated along with the ulnar and radial ends to which the tendon attached after measurement. The proximal portion of the radius and the distal portion of the ulna were embedded and fixed in the dental base acrylic resin powder. The embedded specimen was clamped and fixed by the MTS 858 test machine using a 10 000 N load cell for the entire tensile test. IOM was stretched at a speed of 50 mm/min until it was ruptured. The load-displacement curve was depicted with a computer and the maximum load and stiffness were recorded at the same time. Results: The IOM of the forearm was composed of three portions: central tendinous tissue, membranous tis-sue and dorsal affiliated oblique cord. IOM was stretched at a neutral position, and flexed at pronation and supination positions. The tendinous portion of IOM was lacerated in 6 specimens when the point of the maximum load reached to 1 021.50 N± 250.13 N, the stiffness to 138.24 N/m±24.29 N/m, and the length of stretch to 9.77 mm±l.77 mm. Fracture occurred at the fixed end of the ulna before laceration of the tendinous portion in 4 specimens when the maximum load was 744.40 N±109.85 N, the stiffness was 151.17 N/m±30.68 N/m, and the length of the stretch was 6.51 mm±0.51 mm. Conclusions: The IOM of the forearm is a structure having ligamentous characteristics between the radius and the ulna. It is very important for maintenance of the longitudinal stability of the forearm. The anatomical and biomechanical data can be used as an objective criterion for evaluating the reconstructive method of IOM of the forearm. 展开更多
关键词 FOREARM ANATOMY BIOMECHANICS
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Impaired XPO5 function leads to transportation failure of microRNA precursor
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作者 Yu-Quan Wei 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第6期677-679,共3页
MicroRNAs(miRNAs)constitute a class of small non-coding RNAs that participate in various biological processes by repressing protein translation or destabilizing target mRNAs.miRNA biogenesis begins with the transcri... MicroRNAs(miRNAs)constitute a class of small non-coding RNAs that participate in various biological processes by repressing protein translation or destabilizing target mRNAs.miRNA biogenesis begins with the transcription of primary miRNAs(pri-miRNAs)in the cell nucleus,which are then cleaved by the Drosha/DGCR complex into precursor miRNAs(pre-miRNAs).The pre-miRNAs are transported by exportin-5(XPO5)from the nucleus to the cytoplasm, 展开更多
关键词 miRNAs nucleus microRNA processed mature Dicer constitute cytoplasm impaired transportation
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Growth of single-walled carbon nanotubes from Ag15 cluster catalysts 被引量:1
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作者 Dake Hu Xin He +3 位作者 Lifei Sun Guanchen Xu Liying Jiao Liang Zhao 《Science Bulletin》 SCIE EI CAS CSCD 2016年第12期917-920,共4页
Chirality-specific growth of single-walled carbon nanotubes(SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise sil... Chirality-specific growth of single-walled carbon nanotubes(SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise silver cluster complex [Ag_(15){1,3,5–(C:C)_3–C_6H_3}_2(Py[8])_3–(CF_3SO_3)_3](CF_3SO_3)_6(Py[8] is abbreviation for octamethylazacalix[8]pyridine) as a catalyst precursor. The diameters of most acquired SWNTs distributed in the range of 1.2–1.4 nm, which is suitable for making high performance field-effect transistors. The high quality of the obtained SWNTs was evidenced by Raman spectroscopy and electrical measurements. Successful growth of high quality SWNTs in this study foresees that rational design of metal-organic complexes as growth catalysts can open up a new avenue for the controllable synthesis of SWNTs. 展开更多
关键词 Single-walled carbon nanotube CHIRALITY Metal-organic cluster Catalyst RamanTEM
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