Broad-specificity amino acid racemase, a novel non-antibiotic selectable marker for transgenic plants

Yi‑Chia Kuan,Venkatesan Thiruvengadam,Jia‑Shin Lin,Jia‑Hsin Liu,Tsan‑Jan Chen,Hsin‑Mao Wu,Wen‑Ching Wang,Liang‑Jwu Chen 한국식물생명공학회 2018 Plant biotechnology reports Vol.12 No.1

The broad-specificity amino acid racemase (Bsar) from Pseudomonas putida catalyzes the racemization of various amino acids, offering a flexible and feasible platform to develop a new non-antibiotic selectable marker system for plant transformation. In the present study, we demonstrated that a Bsar variant, Bsar-R174K, that is useful as a selectable marker gene in Arabidopsis and rice that were susceptible to l-lysine and D-alanine. The introduction of wild-type Bsar, Bsar-R174K or Bsar-R174A into E. coli lysine or asparagine auxotrophs was able to rescue the growth of these microorganisms in minimal media supplemented with selectable amino acid enantiomers. The transformation of Arabidopsis with Bsar or Bsar variants based on d-alanine selection revealed that Bsar-R174K had the greatest efficiency (2.40%), superior to kanamycin selectionbased transformation (1.10%). Whereas, l-lysine-based selection exhibited lower efficiency for Bsar-R174K (0.17%). The progenies of selected Bsar-R174K transgenic Arabidopsis revealed normal growth properties. In addition, Bsar-R174K transgenic rice was obtained on l-lysine medium with an efficiency of 0.9%, and the progenies of the transgenic rice revealed morphologically normal phenotypes comparable with their wild-type counterparts. This study presents the first report of broad range amino acid racemase Bsar-R174K as a non-antibiotic selectable marker system applied in transgenic plants.

Short Low Concentration Cisplatin Treatment Leads to an Epithelial Mesenchymal Transition-like Response in DU145 Prostate Cancer Cells

Liu, Yi-Qing,Zhang, Guo-An,Zhang, Bing-Chang,Wang, Yong,Liu, Zheng,Jiao, Yu-Lian,Liu, Ning,Zhao, Yue-Ran Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Background: Prostate cancer is one of the main causes of cancer death, and drug resistance is the leading reason for therapy failure. However, how this occurs is largely unknown. We therrfore aimed to study the response of DU145 cells to cisplatin. Materials and Methods: Du145 prostate cancer cells were treated with a low dose of cisplatin for 24 h and cell viability and number were determined by MTT assay and trypan blue exclusion assay, respectively. The real time polymerase chain reaction (PCR) was used to assess responses to cisplatin treatment. Results: After 24h $2{\mu}g/ml$ treatment did not result in significant reduction in cell viability or number. However, it led to enhanced cancer cell invasiveness. E-cadherin mRNA was reduced, and vimentin, Snail, Slug, metalloproteinase 9 (MMP9) mRNA expression increased significantly, a feature of epithelial-mesenchymal transition (EMT). Conclusions: Short time low concentration cisplatin treatment leads to elevated invasiveness of DU145 cancer cells and this is possibly due to EMT.

Synthesis of Thermoresponsive Hyperbranched Polyamidoamine and the Molecular Weight, pH, and Anion Sensitive Thermoresponsive Properties Thereof

Yi Liu,Yu Chen,Xun-Yong Liu,Hua-Ji Liu,Fa Cheng 한국고분자학회 2012 Macromolecular Research Vol.20 No.6

Hyperbranched polyamidoamine (HPAMAM) polymers, chemically analogous to the commercially available PAMAM dendrimer, were modified with isobutyric anhydride to result in isobutyramide (IBAm) terminated HPAMAMs (HPAMAM-IBAm). The aqueous solutions of HPAMAM-IBAm polymers had the lower critical solution temperature (LCST). The lower molecular-weight HPAMAM-IBAm exhibited higher LCST and the LCST difference was around 18 oC for one pseudo-generation variation. Further, the hyperbranched thermoresponsive polymers exhibited much lower LCSTs than the corresponding dendrimers with similar molecular weight. The LCST of HPAMAM-IBAm was pH sensitive. At pH below 10, the LCST increased significantly upon decreasing the pH,whereas, at pH above 10, the LCST decreased slowly with an increasing pH value. Nine sodium salts were used to measure the anion effect on the LCST of HPAMAM-IBAm. It was found that the LCST could also be modulated up or down in a broad range by simply adding a small amount of different kinds of inorganic anions. The specific ranking of inorganic anions in salting-out HPAMAM4-IBAm polymer was in accordance with the well-known Hofmeister series.

Electrical detection of germination of viable model <i>Bacillus anthracis</i> spores in microfluidic biochips

Liu, Yi-Shao,Walter, T. M.,Chang, Woo-Jin,Lim, Kwan-Seop,Yang, Liju,Lee, S. W.,Aronson, A.,Bashir, R. Royal Society of Chemistry 2007 Lab on a chip Vol.7 No.5

<P>In this paper, we present a new impedance-based method to detect viable spores by electrically detecting their germination in real time within microfluidic biochips. We used <I>Bacillus anthracis</I> Sterne spores as the model organism. During germination, the spores release polar and ionic chemicals, such as dipicolinic acid (DPA), calcium ions, phosphate ions, and amino acids, which correspondingly increase the electrical conductivity of the medium in which the spores are suspended. We first present macro-scale measurements demonstrating that the germination of spores can be electrically detected at a concentration of 10<SUP>9</SUP> spores ml<SUP>−1</SUP> in sample volumes of 5 ml, by monitoring changes in the solution conductivity. Germination was induced by introducing an optimized germinant solution consisting of 10 mM <SMALL>L</SMALL>-alanine and 2 mM inosine. We then translated these results to a micro-fluidic biochip, which was a three-layer device: one layer of polydimethylsiloxane (PDMS) with valves, a second layer of PDMS with micro-fluidic channels and chambers, and the third layer with metal electrodes deposited on a pyrex substrate. Dielectrophoresis (DEP) was used to trap and concentrate the spores at the electrodes with greater than 90% efficiency, at a solution flow rate of 0.2 μl min<SUP>−1</SUP> with concentration factors between 107–109 spores ml<SUP>−1</SUP>, from sample volumes of 1–5 μl. The spores were captured by DEP in deionized water within 1 min (total volume used ranged from 0.02 μl to 0.2 μl), and then germinant solution was introduced to the flow stream. The detection sensitivity was demonstrated to be as low as about a hundred spores in 0.1 nl, which is equivalent to a macroscale detection limit of approximately 10<SUP>9</SUP> spores ml<SUP>−1</SUP>. We believe that this is the first demonstration of this application in microfluidic and BioMEMS devices.</P> <P>Graphic Abstract</P><P>We present an impedance based electrical method to detect germination of viable spores in microfluidic devices. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b702408h'> </P>

FA/Mel@ZnO nanoparticles as drug self-delivery systems for RPE protection against oxidative stress

Yi, Caixia,Yu, Zhihai,Sun, Xin,Zheng, Xi,Yang, Shuangya,Liu, Hengchuan,Song, Yi,Huang, Xiao Techno-Press 2022 Advances in nano research Vol.13 No.1

Drug self-delivery systems can easily realize combination drug therapy and avoid carrier-induced toxicity and immunogenicity because they do not need non-therapeutic carrier materials. So, designing appropriate drug self-delivery systems for specific diseases can settle most of the problems existing in traditional drug delivery systems. Retinal pigment epithelium is very important for the homeostasis of retina. However, it is vulnerable to oxidative damage and difficult to repair. Worse still, the antioxidants can hardly reach the retina by non-invasive administration routes due to the ocular barriers. Herein, the targeted group (folic acid) and antioxidant (melatonin) have been grafted on the surface of ZnO quantum dots to fabricate a new kind of drug self-delivery systems as a protectant via eyedrops. In this study, the negative nanoparticles with size ranging in 4~6 nm were successfully synthesized. They could easily and precisely deliver drugs to retinal pigment epithelium via eyedrops. And they realized acid degradation to controlled release of melatonin and zinc in retinal pigment epithelium cells. Consequently, the structure of retinal pigment epithelium cells were stabilized according to the expression of ZO-1 and β-catenin. Moreover, the antioxidant capacity of retinal pigment epithelium were enhanced both in health mice and photic injury mice. Therefore, such new drug self-delivery systems have great potential both in prevention and treatment of oxidative damage induced retinal diseases.

Study of a Magnetic Switch for the SG-III Energy Module

Liu Gang,Lin Fuchang,Liu Yi,Li Hua,Lee Li,Zeng Han 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

The SG-III energy module, which supplies pumping energy for Xenon (Xe) flashlamps, is one of the most important modules in large laser facilities. A two-electrode spark gap switch is used as the main discharge switch and is triggered by a Marx generator. The peak value of the output impulse generated by the Marx generator is about 180 kV, and its rise time is about 10 ns. In order to prevent the key elements (e.g., Xe flashlamps) from being damaged by the trigger impulse, a magnetic switch is used to isolate the high-voltage impulse. The design, working principle and performance of a magnetic switch based on Fe-based nanocrystals are presented in this paper. Compared with the magnetic switch employed in magnetic pulse compressors (MPCs), the magnetic switch in SGIII works under a single nanosecond impulse. It corresponds to the initial magnetization curve of the B-H curve. The parameters of the Fe-based nanocrystals are obtained by experiments. The unsaturated inductance, saturated inductance and saturation time are the key parameters of the magnetic switch in SG-III and are considered in the design. Finally, the experimental results for the magnetic switch in SG-III are presented.

Analytical and experimental research on wind-induced vibration in high-rise buildings with tuned liquid column dampers

Liu, Ming-Yi,Chiang, Wei-Ling,Chu, Chia-Ren,Lin, Shih-Sheng Techno-Press 2003 Wind and Structures, An International Journal (WAS Vol.6 No.1

In recent years, high-strength, light-weight materials have been widely used in the construction of high-rise buildings. Such structures generally have flexible, low-damping characteristics. Consequently, wind-induced oscillation greatly affects the structural safety and the comfort of the building's occupants. In this research, wind tunnel experiments were carried out to study the wind-induced vibration of a building with a tuned liquid column damper (TLCD). Then, a model for predicting the aerodynamic response in the across-wind direction was generated. Finally, a computing procedure was developed for the analytical modeling of the structural oscillation in a building with a TLCD under the wind load. The model agrees substantially with the experimental results. Therefore, it may be used to accurately calculate the structural response. Results from this investigation show that the TLCD is more advantageous for reducing the across-wind vibration than the along-wind oscillation. When the across-wind aerodynamic effects are considered, the TLCD more effectively controls the aerodynamic response. Moreover, it is also more useful in suppressing the acceleration than the displacement in biaxial directions. As s result, TLCDs are effective devices for reducing the wind-induced vibration in buildings. Parametric studies have also been conducted to evaluate the effectiveness of the TLCD in suppressing the structural oscillation. This study may help engineers to more correctly predict the aerodynamic response of high-rise buildings as well as select the most appropriate TLCDs for reducing the structural vibration under the wind load. It may also improve the understanding of wind-structure interactions and wind resistant designs for high-rise buildings.

Density measurement and equal density temperature of CO2+brine from Dagang - formation from 313 to 363 K

Yi Zhang,Weiwei Jian,Yangchun Zhan,Yongchen Song,Mingjun Yang,Jiafei Zhao,Yu Liu,Weiguo Liu,Yong Shen 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.1

Densities of CO2+Dagang - formation brine solution were measured by a magnetic suspension balance(MSB) in the pressure range from (10 to 18) MPa, at the temperatures from (313.15 to 363.15) K and CO2 mass frac-tions at 0, 0.0101, 0.0198 and 0.0299. The experimental results revealed that the solution densities increased linearlywith the increasing pressure and CO2 concentration, while decreasing with the increasing temperatures in the experi-mental range. When the temperature increased from (313.15 to 363.15) K, the slopes of the densities versus (vs.) CO2mass fractions decreased from (0.193 to 0.106) g·cm−3. A correlation equation was developed based on thermody-namic theory and experimental data. The absolute average deviation between the correlation equation and the experi-mental data was 0.05%, and the maximum deviation was 0.37% for the density of CO2+water/brine solution in com-mon geological storage conditions. According to the density of CO2 - free brine and apparent molar volume of CO2 inbrine, the equal density temperature (Te) of CO2+Dagang brine solution was obtained at 464.67 K when pressure is10MPa, which means that the density of brine dissolved with CO2 will be less than that of CO2-free brine when thetemperature is higher than 464.67 K at 10MPa. In this work the formation temperature of the Dagang oilfield reser-voir is from 313.15 K to 363.15 K, which is lower than the equal density temperature. Therefore, the safety of CO2 stor-age in Dagang oilfield reservoir can be guaranteed.

Design and Implementation of an e-Catalog using XML

Yi Wen Liu,Jin-Gwon Geum,Byeong-do Kang,Young-Jik Kwon 한국산업정보학회 2006 한국산업정보학회 학술대회논문집 Vol.2006 No.5

A miR-155–Peli1–c-Rel pathway controls the generation and function of T follicular helper cells

Liu, Wen-Hsien,Kang, Seung Goo,Huang, Zhe,Wu, Cheng-Jang,Jin, Hyun Yong,Maine, Christian J.,Liu, Yi,Shepherd, Jovan,Sabouri-Ghomi, Mohsen,Gonzalez-Martin, Alicia,Xu, Shunbin,Hoffmann, Alexander,Zheng, The Rockefeller University Press 2016 The Journal of experimental medicine Vol.213 No.9

<P>MicroRNA (miRNA) deficiency impairs the generation of T follicular helper (Tfh) cells, but the contribution of individual miRNAs to this phenotype remains poorly understood. In this study, we performed deep sequencing analysis of miRNAs expressed in Tfh cells and identified a five-miRNA signature. Analyses of mutant mice deficient of these miRNAs revealed that miR-22 and miR-183/96/182 are dispensable, but miR-155 is essential for the generation and function of Tfh cells. miR-155 deficiency led to decreased proliferation specifically at the late stage of Tfh cell differentiation and reduced CD40 ligand (CD40L) expression on antigen-specific CD4<SUP>+</SUP> T cells. Mechanistically, miR-155 repressed the expression of Peli1, a ubiquitin ligase that promotes the degradation of the NF-κB family transcription factor c-Rel, which controls cellular proliferation and CD40L expression. Therefore, our study identifies a novel miR-155–Peli1–c-Rel pathway that specifically regulates Tfh cell generation and function.</P>