Numerical model of the sorting of biological cells based on gravity-driven optoelectronic tweezers

Sheng Hu,Guang-Yuan Si,Rongrong Fu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

Novel gravity-driven optoelectronic tweezers were developed for accurately sorting Jurkat and B16 cells. Synergistic integration of gravity and optoelectronic tweezers was developed as a new tool to provide unique features for sorting or separating mixtures of cells with different dielectric properties. This chip combined flexible programmable virtual electrodes with gravity-driven hydrodynamic flow motion instead of complicated fabrication of micro-pumps and valves. Accordingly, the structure of the microchannel was dimensional, based on a theoretical analysis and numerical model. Using both Jurkat and B16 cells, we obtained the dielectrophoretic separation frequency by using a single-shell model, reflecting their effective complex permittivity. Finally, the results of cellular trajectory analysis demonstrated that the gravity-driven optoelectronic tweezers were able to achieve sorting of Jurkat and B16 cells at a voltage of 11 V with 221.5 kHz, based on a molecular dynamics approach. To further enhance the separation accuracy and reduce the risk of lysing membranes, improved microchannels with two separated branches were designed and studied. Additionally, the shape of the virtual electrode was optimized to generate a greater electrical field magnitude than a rectangular electrode. Thus, the applied electrical voltage could be reduced to 7 V for cell sorting.

An Alkaline pH Control Strategy for Methionine Adenosyltransferase Production in Pichia pastoris Fermentation

Xiaoqing Hu,Ju Chu,Si-Liang Zhang,Ying-ping Zhuang,Xin Wu,Huaxin Chen,Zhongyuan Lv,Zhongyi Yuan 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5

Pichia pastoris is a successful system forexpressing heterologous proteins and its fermentation pH isalways maintained below 7.0. However, particular proteinsare unstable under acidic conditions, such as methionineadenosyltransferase (MAT), and thus fermentation underacidic pH conditions is unsuitable because protein activityis lost owing to denaturation. Here, a strategy employingalkaline pH in the late fermentation period was developedto improve MAT production. Initially, P. pastoris KM71was transformed with the mat gene to overexpress MAT. After 72 h of in vitro incubation at different pH values, theexpressed MAT displayed highest stability at pH 8.0;however, pH 8.0 inhibited cell growth and induced cellrupture, thus affecting protein production. To balance MATstability and Pichia cell viability, different pH controlstrategies were compared. In strategy A (reference), theinduction pH was maintained at 6.0, whereas in strategy B,it was gradually elevated to 8.0 through a 25 h transitionperiod (80 ~ 105 h). MAT activity was 0.86 U/mg (twofoldhigher than the control). However, MAT content wasreduced by 50% when compared with strategy A, becauseof proteases released upon cell lysis. To improve cellviability under alkaline conditions, glycerol was added inaddition to methanol (strategy C). When compared withstrategy B, the MAT-specific activity remained nearlyconstant, whereas the expression level increased to 1.27 g/L. The alkaline pH control strategy presented herein for MATproduction represents an excellent alternative for expressingproteins that are stable only under alkaline conditions.

Transcriptome analysis of rice leaves in response to Rhizoctonia solani infection and reveals a novel regulatory mechanism

De Peng Yuan,Xiao Feng Xu,Hong Woo-Jong,Si Ting Wang,Xin Tong Jia,Yang Liu,Shuang Li,Zhi Min Li,Qian Sun,Qiong Mei,Shuai Li,정기홍,Song Hong Wei,Yuan Hu Xuan 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.5

Sheath blight disease (ShB) severely afects rice production; however, the details of defense against ShB remain unclear. To understand the rice defense mechanism against ShB, an RNA sequencing analysis was performed using Rhizoctonia solani inoculated rice leaves after 48 h of inoculation. Among them, 3417 genes were upregulated and 2532 were downregulated when compared with the control group (>twofold or<1/2). In addition, the diferentially expressed genes were classifed via Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and MapMan analyses. Fifty-nine GO terms and seven KEGG pathways were signifcantly enriched. A MapMan analysis demonstrated that the phytohormone and metabolic pathways were signifcantly altered. Interestingly, the expression levels of 359 transcription factors, including WRKY, MYB, and NAC family members, as well as 239 transporter genes, including ABC, MFS, and SWEET, were signifcantly changed in response to R. solani AG1-IA inoculation. Additionally, OsWRKY53 and OsAKT1 negatively regulate the defense response in rice against R. solani via gain of function study for OsWRKY53 and loss of function study for OsAKT1, respectively. Furthermore, several diferentially expressed genes contain R. solani-responsive cis acting regulatory elements in their promoter regions. Taken together, our analyses provide valuable information for the additional study of the defense mechanisms against ShB, and the candidate genes identifed in this study will be useful resource for future breeding to enhance resistance against ShB.

Effects of superimposed cyclic operation on corrosion products activity in reactor cooling system of AP-1000

Fiaz Mahmood,Huasi Hu,Guichi Lu,Si Ni,Jiaqi Yuan 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.4

It is essential to predict the radioactivity distribution around the reactor cooling system (RCS) duringobligatory cyclic operation of AP-1000. A home-developed program CPA-AP1000 is upgraded to predictthe response of activated corrosion products (ACPs) in the RCS. The program is written in MATLAB and ituses state of the art MCNP as a subroutine for flux calculations. A pair of cyclic power profiles weresuperimposed after initial full power operation. The effect of cyclic operation is noticed to be moreprominent for in-core surfaces, followed by the primary coolant and out-of-core structures. The resultshave shown that specific activity trends of 56Mn and 24Na promptly follow the power variations,whereas, 59Fe, 58Co, 99Mo and 60Co exhibit a sluggish power-following response. The investigationspointed out that promptly power-following response of ACPs in the coolant is vital as an instantradioactivity source during leakage incidents. However, the ACPs with delayed power-following responsein the out-of-core components are perceived to cause a long-term activity. The present results are foundin good agreement with those for a reference PWR. The results are useful for source term monitoring andoptimization of work procedures for an innovative reactor design

New Dioscin-Glycosidase Hydrolyzing Multi-Glycosides of Dioscin from Absidia Strain

( Yao Yao Fu ),( Hong Shan Yu ),( Si Hui Tang ),( Xiang Chun Hu ),( Yuan Hao Wang ),( Bing Liu ),( Chen Xu Yu ),( Feng Xie Jin ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.6

Comparative effectiveness of Chinese herbal injections treating for rotavirus enteritis in children: A systematic review and Bayesian network meta-analysis

Li-Qing Niu,Lu Xiao,Qiu-Han Cai,Yu-Yi Wu,Si-Yuan Hu,Sheng-Xuan Guo,Yu-Ling Tian,Qiu-Rong Wang 한국한의학연구원 2023 Integrative Medicine Research Vol.12 No.2

Background: Rotavirus enteritis (RVE) accounts for 37% of all death in children (<5 years) with diarrhea. Chinese herbal injections (CHIs) have drawn more attention from practitioners because of the valid effects for RVE. However, the most beneficial one has not yet been determined. Methods: Eight databases were searched from their inception up to September 3, 2022. The primary outcome was clinical effective rate and the secondary outcomes were time for disappearance of diarrhea, time of defervescence, time for disappearance of vomiting, and adverse drug reactions or adverse drug events. OpenBUGS 3.2.3 and STATA 14.0 software were employed to carry out the NMA. Results: 58 randomized controlled trials (RCTs) with 6436 child patients were included in this Bayesian NMA. Four CHIs were investigated including Yanhuning injection (YHN), Xiyanping injection (XYP), Reduning injection (RDN), and Zedoary Turmeric Oil injection (ZTO). The results showed that YHN [OR=6.16, 95% CI (4.39, 8.77)] had a superior effect in improving clinical effective rate compared to Ribavirin based on Western medicine (WM). According to SUCRA values, YHN (84.1%) ranked highest. As for the secondary outcomes, XYP was the better intervention in shortening the time for disappearance of diarrhea. Regarding time for defervescence, RDN had obvious advantages and also performed well in time for disappearance of vomiting. Conclusions: CHIs combined with WM could be beneficial than Ribavirin in improving clinical effective rate, and YHN was the optimum treatment. From the comprehensive evaluations of both the clinical effective rate and other outcomes, YHN also indicated a favorable therapeutic effect in RVE. Study registration: This study was registered on PROSPERO (CRD42022357149).