Comparative proteomic analysis of the fungal pathogen Neoscytalidium dimidiatum infection in the pitaya

Limei Pan,Rong Zhang,Fang Lu,Chengming Liu,Jiaxin Fu 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.4

The pathogenic fungus Neoscytalidium dimidiatum (Nd) is the causal agent of pitaya canker and causes significant yield losses. The mechanism by which Nd invades pitaya stems remains largely unknown. Here, quantitative proteomic analysis was employed to investigate pitaya immune responses against Nd infection. A total of 2766 proteins including 244 differentially expressed proteins (DEPs) were identified during infection. Nearly half of the upregulated proteins were predicted to be located in the chloroplast and mitochondrion, implying that these organelles are most affected by fungal infection. Bioinformatics analysis indicated that the DEPs were associated with photosynthesis, phytohormone activity, reactive oxygen species (ROS) homeostasis, and pathogenic defense responses. Notably, the phytohormones auxin and abscisic acid were accumulated for defense against Nd invasion. qRT-PCR validation showed that the mRNA expression levels of auxin binding protein (ABP), auxin response 4 protein (ARP4), and aspartic protease 2 (ASP2) were not consistent with the protein variation, suggesting that these proteins were regulated post-transcriptionally. Additionally, DEPs associated with ROS metabolism changed markedly, indicating that ROS homeostasis in pitaya is important for defense against Nd invasion. In summary, the results revealed the involvement of many essential proteins in the response to Nd infection and provide a basis for studying other biotic stresses of pitaya.

Efficient Bioreduction of Ethyl 4-chloro-3-oxobutanoate to (S)4-chloro-3-hydrobutanoate by Whole Cells of Candida magnoliae in Water/ n-Butyl Acetate Two-phase System

Xua Zhinan,Fang Limei,Lin Jianping,Jiang Xiaoxia,Liu Ying,Cen Peilin The Korean Society for Biotechnology and Bioengine 2006 Biotechnology and Bioprocess Engineering Vol.11 No.1

The asymmetric biosynthesis of ethyl (S)-4-chloro-3-hydrobutanoate from ethyl 4-chloro-3-oxobutanoate was investigated by using whole cells of Candida magnoliae JX120-3 without the addition of glucose dehydrogenase or $NADP^+/NADPH$. In a one-phase system, the bioconversion yield was seriously affected on the addition of 12.1 g/L ethyl 4-chloro-3-oxobutanoate. In order to reduce this substrate inhibition, a water/ n-butyl acetate two-phase system was developed, and the bioreduction conditions optimized with regard to the yield and product enantiometric excess value. The optimal conditions were as following: water to n-butyl acetate volume ratio of 1:1, 4.0 g DCW/L active cells, 50 g/L glucose and $35^{\circ}C$. By adopting a dropwise substrate feeding strategy, high concentration of ethyl 4-chloro-3-oxobutanoate (60 g/L) could be asymmetrically reduced to ethyl (S)-4-chloro-3-hydrobutanoate with high yield (93.8%) and high enantiometric excess value (92.7%).

Efficient Bioreduction of Ethyl 4-chloro-3-oxobutanoate to (S)-chloro-3-hydrobutanoate by Whole Cells of Candida magnoliae in Water/n-Butyl Acetate Two-phase System

Zhinan Xu,Limei Fang,Jianping Lin,Xiaoxia Jiang 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.1

The asymmetric biosynthesis of ethyl (S)-4-chloro-3-hydrobutanoate from ethyl 4-chloro-3-oxobutanoate was investigated by using whole cells of Candida magnoliae JX120-3 without the addition of glucose dehydrogenase or NADP+/NADPH. In a one-phase system, the bioconversion yield was seriously affected on the addition of 12.1 g/L ethyl 4-chloro-3-oxobutanoate. In order to reduce this substrate inhibition, a water/n-butyl acetate two-phase system was developed, and the bioreduction conditions optimized with regard to the yield and product enantiometric excess value. The optimal conditions were as following: water to n-butyl acetate volume ratio of 1:1, 4.0 g DCW/L active cells, 50 g/L glucose and 35°C. By adopting a dropwise substrate feeding strategy, high concentration of ethyl 4-chloro-3-oxobutanoate (60 g/L) could be asymmetrically reduced to ethyl (S)-4-chloro-3-hydrobutanoate with high yield (93.8%) and high enantiometric excess value (92.7%).

Kinetics and optimization of L-tryptophan separation with ion-exchange chromatography

Wei Luo,Limei Fan,Peilian Wei,Hao Chen,Limei Fang,Jin Huang,Zhinan Xu,Peilin Cen 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

Adsorption and desorption of L-tryptophan (L-trp) on strong acid cation exchange resin were investigated in a fixed-bed column. L-trp was effectively adsorbed onto the resin HZ-001, with the loading capacity and breakthrough time determined. Four kinetic models, including Adams-Bohard, Wolborska, Thomas, and Yoon-Nelson models,were adopted to determine the kinetic parameters of adsorption and to predict the breakthrough curves. The results showed that the models used described the breakthrough well. Desorption of L-trp from the column bed was performed using aqueous ammonia as the eluant. Optimum procedure was obtained with 2.0M aqueous ammonia at the elution velocity of 6 BV/h. Five cycles of adsorption-elution-regeneration were conducted to evaluate the column reutilization.

Screening nephroprotective compounds from cortex Moutan by mesangial cell extraction and UPLC

Min Sun,Limei Huang,Jianliang Zhu,Wenjie Bu,Jing Sun,Zhaohui Fang 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.6

A method for screening nephroprotective compoundsin cortex Moutan, a common traditional Chinesemedicine (TCM) in treating diabetic nephropathy with renalmesangial cell extraction and ultra performance liquidchromatography technique was described in this paper. Wehypothesize that the compounds which bind to cell membranesunder pathological conditions may be the bioactivecompounds in TCMs. Mesangial cells were cultured inmedium containing 5 mM (physiological, NG) or 30 mM(pathological, HG) glucose for 48 h and then incubated withcortex Moutan extract. After the unbound substances werewashed off, the cell membrane-bound compounds weredissociated and concentrated by an SPE column. By comparingthe chromatograms of NG and HG cultured-cellextractions and cortex Moutan extract, three compoundsbound to both NG and HG-cultured mesangial cells wereidentified as paeoniflorin, pentagalloylglucose (PGG) andpaeonol. In vitro studies showed that paeoniflorin, PGG andpaeonol reduced the activity of nicotinamide-adenine dinucleotidephosphate oxidase (NADPH) activity, anddecreased the level of reactive oxygen species (ROS),transforming growth factor-b1 (TGF-b1) and fibronectin inhigh glucose cultured mesangial cells. The results indicatethat paeonol, paeoniflorin and PGG may be the nephroprotectivecompounds from cortex Moutan. This study isexpected to provide a more reliable and effective method forscreening bioactive compounds from the complex TCM systems.

Feedback Linearization Adaptive Dynamic Sliding Mode Control of Linear Synchronous Motor for CNC Machine Tools

Zhang Kang,Wang Limei,Fang Xin 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

This study aims to develop a feedback linearization adaptive dynamic sliding mode control strategy to solve the coupling problem between electrical and mechanical in a permanent magnet linear synchronous motor servo system (PMLSM) of CNC machine tools. To improve the dynamic and steady performance of the linear servo system, the feedback linearization control method is adopted in this paper. By coordinate transformation and state feedback, the affi ne nonlinear model of the motor is decoupled and linearized into an independent current subsystem and linear velocity subsystem. Based on the linearization model, a dynamic sliding mode controller is designed to reduce the dependence of feedback linearization control on the mathematical model of PMLSM and improve the robustness of the servo system. In addition, an adaptive control law is designed to estimate the uncertainty of the system and reduce the chattering. Simulation and experiment demonstrate that the proposed control strategy can not only eff ectively improve the performance of velocity tracking, but also enhance the robustness of the system.

Genetic Diversity and Population Structure of the Xanthomonas campestris pv. campestris Strains Affecting Cabbages in China Revealed by MLST and Rep-PCR Based Genotyping

Guo Chen,Congcong Kong,Limei Yang,Mu Zhuang,Yangyong Zhang,Yong Wang,Jialei Ji,Zhiyuan Fang,Honghao Lv 한국식물병리학회 2021 Plant Pathology Journal Vol.37 No.5

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 Xcc strains including 39 Xcc isolates collected from cabbage in 20 regions across China, us- ing multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative Xcc strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for Xcc strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-Xcc interaction studies.

Adsorption behavior of L_tryptophan on ion exchange resin

Wei Luo,Lei Huang,Hao Chen,Limei Fang,Jin Huang,Zhinan Xu,Peilin Cen 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

A batch method was applied to investigate the adsorption behavior and mechanisms of L_tryptophan (Ltrp)on ion exchange resins. HZ-001 and JK006 were proved to be ideal adsorbents due to their large loading capacity and favorable selective adsorption for L-trp. Langmuir, Freundlich, and Dubinin-Radushkevich equations were applied to simulate the experimental data to describe the adsorption process of L_trp onto HZ_001 and JK006. The maximum loading capacity (at pH 5.0, 30 ℃), determined by the Langmuir and Dubinin-Radushkevich models, was close to each other (833 mg/g vs. 874 mg/g) for HZ_001, while discrepant (833 mg/g vs. 935 mg/g) for JK006. Three diffusion-controlled kinetic models were utilized to analyze the results in order to identify the adsorption mechanism. The adsorption kinetics of L_trp onto cation exchange resins was investigated under different experimental conditions, including initial solution pH, temperature, initial L-trp concentration, and adsorbent dosage. Moreover, the diffusion process of L_trp onto HZ_001 and JK006 was evaluated at different initial adsorbate concentrations. The thermodynamic parameters,obtained from the kinetic data, demonstrated that L-trp could be adsorbed spontaneously onto both resins.

Conductively coupled flexible silicon electronic systems for chronic neural electrophysiology

Li, Jinghua,Song, Enming,Chiang, Chia-Han,Yu, Ki Jun,Koo, Jahyun,Du, Haina,Zhong, Yishan,Hill, Mackenna,Wang, Charles,Zhang, Jize,Chen, Yisong,Tian, Limei,Zhong, Yiding,Fang, Guanhua,Viventi, Jonathan National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.41

<P>Materials and structures that enable long-term, intimate coupling of flexible electronic devices to biological systems are critically important to the development of advanced biomedical implants for biological research and for clinical medicine. By comparison with simple interfaces based on arrays of passive electrodes, the active electronics in such systems provide powerful and sometimes essential levels of functionality; they also demand long-lived, perfect biofluid barriers to prevent corrosive degradation of the active materials and electrical damage to the adjacent tissues. Recent reports describe strategies that enable relevant capabilities in flexible electronic systems, but only for capacitively coupled interfaces. Here, we introduce schemes that exploit patterns of highly doped silicon nanomembranes chemically bonded to thin, thermally grown layers of SiO2 as leakage-free, chronically stable, conductively coupled interfaces. The results can naturally support high-performance, flexible silicon electronic systems capable of amplified sensing and active matrix multiplexing in biopotential recording and in stimulation via Faradaic charge injection. Systematic in vitro studies highlight key considerations in the materials science and the electrical designs for high-fidelity, chronic operation. The results provide a versatile route to biointegrated forms of flexible electronics that can incorporate the most advanced silicon device technologies with broad applications in electrical interfaces to the brain and to other organ systems.</P>