期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
米曲霉酸性蛋白酶基因在毕赤酵母中的异源表达及酶学性质 被引量:11
1
作者 岳晓平 陈朋 +5 位作者 朱玥明 曾艳 刘汉民 刘红彦 王敏 孙媛霞 《生物工程学报》 CAS CSCD 北大核心 2019年第3期415-424,共10页
酸性蛋白酶作为一类重要的天冬氨酸蛋白酶,被广泛应用于食品、医药和皮革等领域。为推动酸性蛋白酶的研究及应用,通过对发酵豆制品样品进行宏基因组测序,从中获得米曲霉酸性蛋白酶基因pepA,在毕赤酵母GS115中进行异源表达,并对重组酶Pep... 酸性蛋白酶作为一类重要的天冬氨酸蛋白酶,被广泛应用于食品、医药和皮革等领域。为推动酸性蛋白酶的研究及应用,通过对发酵豆制品样品进行宏基因组测序,从中获得米曲霉酸性蛋白酶基因pepA,在毕赤酵母GS115中进行异源表达,并对重组酶PepA进行酶学性质分析。结果显示毕赤酵母发酵上清液中酸性蛋白酶的活性为50.62 U/mL。SDS-PAGE验证PepA的分子量约为50 kDa,且发酵上清液几乎无杂蛋白。PepA的最适pH值为4.5,最适温度为50℃,Mn^(2+)和Cu^(2+)对其具有激活作用,而Fe^(3+)、Fe^(2+)与Ca^(2+)则具有抑制作用。上述研究结果可为米曲霉酸性蛋白酶的异源表达及其相关工业应用提供指导。 展开更多
关键词 米曲霉 酸性蛋白酶 毕赤酵母 异源表达 酶学性质
原文传递
A Novel Zeroing Neural Network for Time-Varying Matrix Pseudoinversion in the Presence of Linear Noises
2
作者 Jianfeng Li Linxi Qu +2 位作者 yueming zhu Zhan Li Bolin Liao 《Tsinghua Science and Technology》 2025年第5期1911-1926,共16页
The computation of matrix pseudoinverses is a recurrent requirement across various scientific computing and engineering domains.The prevailing models for matrix pseudoinverse typically operate under the assumption of ... The computation of matrix pseudoinverses is a recurrent requirement across various scientific computing and engineering domains.The prevailing models for matrix pseudoinverse typically operate under the assumption of a noise-free solution process or presume that any noise present has been effectively addressed prior to computation.However,the concurrent real-time computation of time-varying matrix pseudoinverses holds significant practical utility,while the preemptive preprocessing for noise elimination or reduction may impose supplementary computational overheads on real-time implementations.Different from previous models for solving the pseudoinverse of time-varying matrices,in this paper,a model for solving the pseudoinverse of time-varying matrices using a double-integral structure,called Double-lntegral-Enhanced Zeroing Neural Network(DIEZNN)model,is proposed and investigated,which is capable of solving timevarying matrix pseudoinverse while efficiently eliminating the negative effects of linear noise perturbations.The experimental results show that in the presence of linear noise,the DIEzNN model demonstrates better noise suppression performance compared to both the original zeroing neural network model and the Zeroing Neural Network(ZNN)model enhanced with a Li-type activation function.In addition,these models are applied to the control of chaotic system of controllable permanent magnet synchronous motor,which further verifies the superiority of DIEZNN in engineeringapplication. 展开更多
关键词 Zhang Function(ZF) matrix pseudoinverse ROBUSTNESS real-time systems
原文传递
Active dry yeast supplementation improves the growth performance,rumen fermentation, and immune response of weaned beef calves 被引量:15
3
作者 Jian Ma Cheng Wang +10 位作者 Zhisheng Wang Guang Cao Rui Hu Xueying Wang Huawei Zou Kun Kang Quanhui Peng Bai Xue Lizhi Wang yueming zhu Xiaopeng zhu 《Animal Nutrition》 SCIE CSCD 2021年第4期1352-1359,共8页
The objective of this experiment was to investigate the potential benefits of active dry yeast(ADY)on the growth performance,rumen fermentation,nutrient digestibility,and serum parameters of weaned beef calves.Thirty ... The objective of this experiment was to investigate the potential benefits of active dry yeast(ADY)on the growth performance,rumen fermentation,nutrient digestibility,and serum parameters of weaned beef calves.Thirty Simmental crossbred male calves(body weight=86.47±4.41 kg and 70±4 d of age)were randomly divided into 2 groups:control(CON)(fed basal ration)and ADY(fed basal ration and 5 g/d ADY per calf).The dietary concentrate-to-roughage ratio was 35:65.All the calves were regularly provided rations 3 times a day at 07:00,13:00,and 19:00 and had free access to wate r.The experiment lasted for 60 d.The average daily gain of ADY group was higher(P=0.007)than that of the CON group,and the ratio of feed intake to average daily gain in the ADY group was reduced(P=0.022)as compared to the CON group.The concentration of ruminal ammonia-N was higher(P=0.023)in the CON group than that in the ADY group,but an opposite trend of microbial protein was found between the 2 groups.Also,the ruminal concentrations of propionate and butyrate were higher(P<0.05)in the ADY group than those in the CON group.Calves fed ADY exhibited higher(P<0.05)crude protein and neutral detergent fiber digestibility.Supplementation of ADY increased(P<0.05)the contents of glucose,glutathione peroxidase,superoxide dismutase,immunoglobulin A,immunoglobulin M,and interleukin 10 in the serum of calves,but an opposite trend was observed in malondialdehyde,interleukin 1 beta,and tumor necrosis factor alpha contents between the 2 groups.In conclusion,dietary supplementation with ADY could improve the growth performance,rumen fermentation,nutrient digestibility,antioxidant ability,and immune response of weaned beef calves. 展开更多
关键词 Active dry yeast Weaned beef calf Growth performance Rumen fermentation Nutrient digestibility Immune response
原文传递
Crystal structures of D-psicose 3-epimerase from Clostridium cellulolyticum H10 and its complex with ketohexose sugars 被引量:7
4
作者 Hsiu-Chien Chan yueming zhu +7 位作者 Yumei Hu Tzu-Ping Ko Chun-Hsiang Huang Feifei Ren Chun-Chi Chen Yanhe Ma Rey-Ting Guo Yuanxia Sun 《Protein & Cell》 SCIE CSCD 2012年第2期123-131,共9页
D-Psicose 3-epimerase(DPEase)is demonstrated to be useful in the bioproduction of D-psicose,a rare hexose sugar,from D-fructose,found plenty in nature.Clostridium cellulolyticum H10 has recently been identified as a D... D-Psicose 3-epimerase(DPEase)is demonstrated to be useful in the bioproduction of D-psicose,a rare hexose sugar,from D-fructose,found plenty in nature.Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase.In this study,the crystal structure of the C.cellulolyticum DPEase was determined.The enzyme assembles into a tetramer and each subunit shows a(β/α)8 TIM barrel fold with a Mn2+metal ion in the active site.Additional crystal structures of the enzyme in complex with substrates/products(D-psicose,D-fructose,D-tagatose and D-sorbose)were also determined.From the complex structures of C.cellulolyticum DPEase with D-psicose and D-fructose,the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues.Accordingly,based on these ketohexosebound complex structures,a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here.These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis. 展开更多
关键词 D-psicose 3-epimerase ketohexose complex structure
原文传递
Stability evaluation of the PROSPECT model for leaf chlorophyll content retrieval
5
作者 Li Zhai Liang Wan +5 位作者 Dawei Sun Alwaseela Abdalla yueming zhu Xiaoran Li Yong He Haiyan Cen 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2021年第5期189-198,共10页
The radiative transfer model,PROSPECT,has been widely applied for retrieving leaf biochemical traits.However,little work has been conducted to evaluate the stability of the PROSPECT model with consideration of multipl... The radiative transfer model,PROSPECT,has been widely applied for retrieving leaf biochemical traits.However,little work has been conducted to evaluate the stability of the PROSPECT model with consideration of multiple factors(i.e.,spectral resolution,signal-to-noise ratio,plant growth stages,and treatments).This study aims to investigate the stability of the PROSPECT model for retrieving leaf chlorophyll(Chl)content(Cab).Leaf hemispherical reflectance and transmittance of oilseed rape were acquired at different spectral resolutions,noise levels,growth stages,and nitrogen treatments.The Chl content was also measured destructively by using a microplate spectrophotometer.The performance of the PROSPECT model was compared with a commonly used random forest(RF)model.The results showed that the prediction accuracy of PROSPECT and RF models for Cab did not produce significant differences under varied spectral resolutions ranging from 1 to 20 nm.The ranges of the relative root mean square errors(rRMSE)of the PROSPECT and RF models were 12%-13%and 11.70%-12.86%,respectively.However,the performance of both models for leaf Chl retrieval was strongly influenced by the noise level with the rRMSE of 13-15.37%and 12.04%-15.80%for PROSPECT and RF,respectively.For different growth stages,the PROSPECT model had similar prediction accuracies(rRMSE=9.26%-12.41%)to the RF model(rRMSE=9.17%-12.70%).Furthermore,the superiority of the PROSPECT model(rRMSE=10.10%-12.82%)over the RF model(rRMSE=11.81%-15.47%)was prominently observed when tested with plants growth at different nitrogen treatment levels.The results demonstrated that the PROSPECT model has a more stable performance than the RF model for all datasets in this study. 展开更多
关键词 leaf chlorophyll content oilseed rape PROSPECT spectral resolution spectral noise nitrogen treatment
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部