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Search Results: 1 - 10 of 78206 matches for " Shengdi Chen "
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Translational Neurodegeneration, a platform to share knowledge and experience in translational study of neurodegenerative diseases
Shengdi Chen, Jialin C Zheng
Translational Neurodegeneration , 2012, DOI: 10.1186/2047-9158-1-1
Abstract: Indeed, the prevalence of neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD), has increased significantly as global populations age. Specifically, the number of cases of dementia in the developed world is projected to rise from 13.5 million in 2000 to 21.2 million in 2025, and to 36.7 million in 2050[1]. Currently, the number of deaths caused by AD is only next to the number of deaths caused by stroke. As the prevalence of AD grows, so does the cost to a nation. For PD, the second most common neurodegenerative disease after AD, more than 4 million people suffer from this devastating disease worldwide and that will double in the next 25 years [2]. To date, PD is still an incurable progressive neurological disorder that seriously impairs the quality of life.The discovery and application of levodopa (L-dopa) is one of the best examples of translational research for neurodegenerative diseases. In 1910s, L-dopa was first isolated from seedlings of Vicia faba; and in 1938, L-dopa decarboxylase was discovered, which can produce dopamine (DA) from L-dopa. In 1959, DA was found enriched in the basal ganglia; and in 1960, a severe striatal DA deficit was demonstrated in PD patients. These major discoveries and a deepening understanding of the neurochemistry of DA and the neuropathology of PD led to the concept of "DA replacement" with L-dopa. In 1961, L-dopa was tried in PD patients by i.v. treatment. In 1967, oral administration of L-dopa was reported to produce dramatic improvements in PD patients with increasing amounts over long periods [3]. However, the main side effects of increasing L-dopa administration, i.e., dyskinesias and motor fluctuations, became apparent. This clinical finding confused doctors and patients, and a solution was needed. In 1970s, the key cause was found. L-dopa decarboxylase degraded L-dopa to DA in peripheral blood, which can not across the blood-brain barrier. These findings led to the first L-dopa combi
Volume Quantification of Acute Infratentorial Hemorrhage with Computed Tomography: Validation of the Formula 1/2ABC and 2/3SH
Wanlin Yang, Yulan Feng, Yunyun Zhang, Jing Yan, Yi Fu, Shengdi Chen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062286
Abstract: Objective To compare the accuracy of formula 1/2ABC with 2/3SH on volume estimation for hypertensive infratentorial hematoma. Methods One hundred and forty-seven CT scans diagnosed as hypertensive infratentorial hemorrhage were reviewed. Based on the shape, hematomas were categorized as regular or irregular. Multilobular was defined as a special shape of irregular. Hematoma volume was calculated employing computer-assisted volumetric analysis (CAVA), 1/2ABC and 2/3SH, respectively. Results The correlation coefficients between 1/2ABC (or 2/3SH) and CAVA were greater than 0.900 in all subgroups. There were neither significant differences in absolute values of volume deviation nor percentage deviation between 1/2ABC and 2/3SH for regular hemorrhage (P>0.05). While for cerebellar, brainstem and irregular hemorrhages, the absolute values of volume deviation and percentage deviation by formula 1/2ABC were greater than 2/3SH (P<0.05). 1/2ABC and 2/3SH underestimated hematoma volume each by 10% and 5% for cerebellar hemorrhage, 14% and 9% for brainstem hemorrhage, 19% and 16% for regular hemorrhage, 9% and 3% for irregular hemorrhage, respectively. In addition, for the multilobular hemorrhage, 1/2ABC underestimated the volume by 9% while 2/3SH overestimated it by 2%. Conclusions For regular hemorrhage volume calculation, the accuracy of 2/3SH is similar to 1/2ABC. While for cerebellar, brainstem or irregular hemorrhages (including multilobular), 2/3SH is more accurate than 1/2ABC.
DJ-1 can inhibit microtubule associated protein 1 B formed aggregates
Zhiquan Wang, Yu Zhang, Shi Zhang, Qianqian Guo, Yuyan Tan, Xinyi Wang, Ran Xiong, Jianqing Ding, Shengdi Chen
Molecular Neurodegeneration , 2011, DOI: 10.1186/1750-1326-6-38
Abstract: We presented evidence that DJ-1 could bind to microtubule associated protein1b Light Chain (MAP1b-LC). Overexpression of DJ-1 prevented MAP1b-LC aggregation in HEK293t and SH-SY5Y cells while DJ-1 knocking down (KD) enhanced MAP1b-LC aggregation in SH-SY5Y cells. The increase in insoluble MAP1b-LC was also observed in the DJ-1 null mice brain. Moreover, in the DJ-1 KD SH-SY5Y cells, overexpression of MAP1B-LC led to endoplasmic reticulum (ER) stress-induced apoptosis.Our results suggest that DJ-1 acts as a molecular chaperone to inhibit MAP1B aggregation thus leading to neuronal apoptosis. Our study provides a novel insight into the mechanisms that underly the pathogenesis of Parkinson's disease (PD).PD is a common neurodegenerative disease which affects approximately 1% of individuals of 65 years and 5% of those 85 years or older. The featured pathological changes of PD are the selective and progressive loss of dopaminergic (DA) neurons as well as protein aggregation and Lewy body formation [1,2]. Lewy bodies mainly constitute of aggregated α-synuclein protein and they also contain cytoskeletal components and other proteins. Although the role of protein aggregation in the pathogenesis of neurodegenerative diseases remains controversial, many studies have shown that protein aggregation contributes to neurodegeneration [2-5]. Failure to clear misfolded proteins leads to protein aggregation, which may in turn lead to the pathogenesis of neurodegenerative diseases.It has been reported that cytoskeletal proteins are involved in the pathology of neurodegenerative diseases [6,7]. For example, tau has been linked to both Alzheimer's disease (AD) and PD [8,9]. MAP1b has also been reported to participate in the pathogenesis of Fragile X syndrome [10] and Giant axonal neuropathy [11]. MAP1b plays a principal role in the development of the nervous system and is essential for normal development of the murine nervous system [12,13]. It has been reported that MAP1b co-localized w
The Genetic Variation of SORCS1 Is Associated with Late-Onset Alzheimer’s Disease in Chinese Han Population
Wei Xu, Jun Xu, Ying Wang, Huidong Tang, Yulei Deng, Rujing Ren, Gang Wang, Wenquan Niu, Jianfang Ma, Yiwen Wu, Jialin Zheng, Shengdi Chen, Jianqing Ding
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063621
Abstract: The variations of SORCS1 gene may play potential key roles in late-onset Alzheimer’s disease (LOAD). To evaluate the relationship between the polymorphism of SORCS1 gene and LOAD in the ethnic Han Chinese, we conducted a case–control study to investigate the association between the single-nucleotide polymorphisms (SNPs) in intron 1 of SORCS1 and LOAD in Chinese Han population. Six reported SNPs in intron 1 of SORCS1 were analyzed by Snapshot, genotyping and haplotyping in 236 Chinese LOAD cases and 233 matched controls. The significant differences in frequencies of two SNPs (rs10884402, rs950809) were found between the two groups. In addition, haplotype analyses revealed that, in the LOAD group, the frequency of haplotypes C-C-G-T-C (alleles in order of rs17277986, rs6584777, rs10884402, rs7078098, rs950809 polymorphisms) were significantly higher (Psim<0.0001) while haplotype C-C-A-T-C, C-C-A-C-C, T-T-A-C-C were significantly lower (Psim<0.0001). Our data suggested that the genetic variation of the rs10884402 and rs950809 in intron 1 of SORCS1 was associated with the late-onset AD in the Chinese Han population.
Controlled low-strength material incorporating recycled fineaggregate from urban red brick based construction waste
Ran Jin, , Zhang Jinxi, Yang Mijia, Jia Dongdong, Lu Shengdi
- , 2017, DOI: 10.3969/j.issn.1003-7985.2017.04.017
Abstract: Sixteen controlled low-strength material(CLSM)mixtures with various cement-to-sand(C/Sa)ratios and water-to-solid(W/So)ratios were prepared using recycled fine aggregate from urban red brick based construction waste. The fluidity and bleeding of the fresh CLSM mixtures were measured via the modified test methods, and the hardened CLSM mixtures were then molded to evaluate their compressive strength and durability. The results show that the fluidity of the fresh CLSM mixtures is 105 to 227 mm with the corresponding bleeding rate of 3.7% to 15.5%, which increases with the increase in fluidity. After aging for 28 d, the compressive strength of the hardened CLSM mixtures reaches 1.15 to 13.96 MPa, and their strength can be further enhanced with longer curing ages. Additionally, the strength increases with the increase of the C/Sa ratio, and decreases with the increase of the W/So ratio under the same curing age. Based on the obtained compressive strength, a fitting model for accurately predicting the compressive strength of the CLSM mixtures was established, which takes into account the above two independent variables(C/Sa and W/So ratios). Moreover, the durability of the hardened CLSM mixtures is enhanced for samples with higher C/Sa ratios.
Functional Reconstitution of Staphylococcus aureus Truncated AgrC Histidine Kinase in a Model Membrane System
Lina Wang, Chunshan Quan, Baoquan Liu, Jianfeng Wang, Wen Xiong, Pengchao Zhao, Shengdi Fan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080400
Abstract: The integral membrane protein AgrC is a histidine kinase whose sensor domains interact with an autoinducing peptide, resulting in a series of downstream responses. In this study, truncated AgrCTM5-6C and AgrCTM5-6C-GFP with GFP as a reporter gene were produced using a bacterial system. Purified AgrCTM5-6C and AgrCTM5-6C-GFP were reconstituted into liposomes by a detergent-mediated method. To achieve high-yield protein incorporation, we investigated the effect of different detergents on protein reconstitution efficiency. The highest incorporation was found with N,N-dimethyldode-cylamine N-oxide during complete liposome solubilization, which resulted in a yield of 85±5%. The COOH-terminus of the protein AgrCTM5-6C was almost exclusively oriented towards the inside of the vesicles. AgrCTM5-6C in proteoliposomes exhibited approximately a 6-fold increase in constitutive activity compared with AgrCTM5-6C in detergent micelles. The reconstitution of AgrCTM5-6C or AgrCTM5-6C-GFP was characterized using dynamic light scattering, fluorescence microscopy, and transmission electron microscopy. Based on the results, the optimal conditions for protein incorporation were defined. These findings contribute to the study of membrane protein structure and function in vitro using a reconstitution system.
Green Fluorescent Protein (GFP)-Based Overexpression Screening and Characterization of AgrC, a Receptor Protein of Quorum Sensing in Staphylococcus aureus
Lina Wang,Chunshan Quan,Baoquan Liu,Yongbin Xu,Pengchao Zhao,Wen Xiong,Shengdi Fan
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms140918470
Abstract: Staphylococcus aureus AgrC is an important component of the agr quorum-sensing system. AgrC is a membrane-embedded histidine kinase that is thought to act as a sensor for the recognition of environmental signals and the transduction of signals into the cytoplasm. However, the difficulty of expressing and purifying functional membrane proteins has drastically hindered in-depth understanding of the molecular structures and physiological functions of these proteins. Here, we describe the high-yield expression and purification of AgrC, and analyze its kinase activity. A C-terminal green fluorescent protein (GFP) fusion to AgrC served as a reporter for monitoring protein expression levels in real time. Protein expression levels were analyzed by the microscopic assessment of the whole-cell fluorescence. The expressed AgrC-GFP protein with a C-terminal His-tagged was purified using immobilized metal affinity chromatography (IMAC) and size exclusion chromatography (SEC) at yields of ≥10 mg/L, following optimization. We also assessed the effects of different detergents on membrane solubilization and AgrC kinase activity, and polyoxyethylene-(23)-lauryl-ether (Brij-35) was identified as the most suitable detergent. Furthermore, the secondary structural stability of purified AgrC was analyzed using circular dichroism (CD) spectroscopy. This study may serve as a general guide for improving the yields of other membrane protein preparations and selecting the appropriate detergent to stabilize membrane proteins for biophysical and biochemical analyses.
Expression profiling of genes involved in Taxuyunnanine C biosynthesis in cell suspension cultures of Taxus chinensis by repeated elicitation with a newly synthesized jasmonate and sucrose feeding

Mingbo Gao,Wei Zhang,Xingtai Li,Chengjiang Ruan,Shengdi Fan,

生物工程学报 , 2011,
Abstract: 红豆杉悬浮培养细胞具有可持续生产抗癌药物紫杉醇及其他紫杉烷的潜力。在中国红豆杉悬浮培养细胞中,云南紫杉烷 C(Tc) 是主要的次生代谢产物。为促使代谢前体由生成其他紫杉烷的代谢支路转到生产紫杉醇,实验采用实时定量PCR技术 (RQ-PCR) 揭示细胞培养过程中紫杉醇及紫杉烷合成关键基因的动态变化。在细胞培养的第7天和第12天,以100 μmol/L 2,3-二羟丙基茉莉酸 (DHPJA) 进行诱导,同时在第7天饲喂20 g/L的蔗糖,在此过程中考察6个关键基因 (TASY,TDAT,T5αH,TαH,T10βH和T14βH) 的表达变化。上述联合调控手段使得Tc产量在第1次诱导8 d后达 (554.46±21.28) mg/L,第2次诱导9 d后高达 (997.72±1.51) mg/L。代谢早期基因TASY和TDAT在第1次诱导后表达量分别提高了182和98倍,在第2次诱导后表达量分别提高了208和131倍。在每次诱导后基因表达量提高约持续24 h,之后下降。其他4个基因 (T5αH、TαH、T10βH和T14βH) 的情况有所不同。基因TαH在2次诱导后表达量分别提高了3 061和1 016倍。其他3个基因T5αH、T10βH、T14βH在第1次诱导后表达量分别提高13、38、20倍,在第2次诱导后分别提高7、16、6倍。RQ-PCR结果表明基因表达和Tc积累之间存在紧密相关性:基因表达的变化与Tc产量的变化相一致,诱导可提高6个基因的表达量。基因的高表达随着培养过程逐渐衰减,再次诱导可再次促使基因的高表达。
Simplification and optimization of the preparation of Escherichia coli extract for cell-free protein expression

Xinjuan Guo,Chunshan Quan,Pengchao Zhao,Lina Wang,Shengdi Fan,

生物工程学报 , 2013,
Abstract: 无细胞蛋白表达系统是一种将目的蛋白在体外进行表达的新技术和新方法,已广泛应用到蛋白质组学、蛋白质结构和功能等领域的研究中。在无细胞蛋白表达系统中,细胞抽提物的制备是关键因素之一。通过对大肠杆菌细胞抽提物制备过程中离心速度、预孵化和透析等参数的考察,利用绿色荧光蛋白作为报告蛋白,可以得到一个细胞抽提物制备的简化方案。采用相对低的转速 (12 000×g,10 min),简易空孵化即可制备出活性高的细胞抽提物,用于无细胞体系蛋白表达,其表达的绿色荧光蛋白产量为209 μg/mL。与传统的大肠杆菌细胞抽提物S30相比较,新方案将使时间与成本节省62%,产量是传统方法的2.6倍,使无细胞蛋白表达技术的操作快速、高通量的优势更加明显。
Research on the Incentive Mechanism of Hidilao Hotpot’s Employees Based on Grounded Theory  [PDF]
Chen Chen
Journal of Human Resource and Sustainability Studies (JHRSS) , 2018, DOI: 10.4236/jhrss.2018.61031
Abstract: The traditional classical incentive model only reveals the general rule of organizational incentive, and does not give specific operation rules. The matching between organizational incentives and employee needs is still black box, and it does not reveal its core operation mechanism from the perspective of mechanism. This paper took through the literature review, the Hidilao Hotpot company as a case study, through a variety of ways to collect data, the use of grounded theory to encode data analysis, and ultimately extracted 58 concepts, 26 sub-areas, 7 main areas, concluded that the Hidilao Hotpot Employee motivation formed the path, and ultimately extracted the micro-level employee motivation mechanism model. The research result of this article comes from the practice of the enterprise, which has enlightenment to the organizational incentive of the traditional catering industry and also provides a micro-research perspective and systematic mechanism research for the incentive field.
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