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.

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.

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.

Studies on Lao-Chao Culture Filtrate for a Flavoring Agent in a Yogurt-Like Product

Liu, Yi-Chung,Chen, Ming-Ju,Lin, Chin-Wen Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.4

Lao-chao is a traditional Chinese fermented rice product with a sweet and fruity flavor, containing high levels of glucose, a little alcohol and milk-clotting characteristics. In order to optimize commercial production of lao-chao, Rhizopus javanicus and Saccharomyces cerevisiae were selected as the mold and yeast starter, respectively. A commercial mixed starter (chiu-yao) was used as control. Fermentation of the experimental combination revealed a sharp drop in pH (to 4.5) on the fourth day, remaining constant thereafter. Content of reducing sugars gradually decreased throughout the entire fermentation period. Of the free amino acids, higher quantities of alanine, leucine, proline, glutamic acid, glutamine and $NH_3$ were noted. For sugars, glucose revealed the highest concentration, while organic acid levels, including those for oxalic, lactic, citric and pyroglutamic acid, increased throughout the fermentation period. Twenty-one compounds were identified by gas chromatography from aroma concentrates of the lao-chao culture filtrate, prepared using the headspace method. For the flavor components, higher quantities of ethanol, fusel oil and ester were determined in both culture filtrates. In regard to the evaluation of yogurt-like product, there were significant differences in alcoholic smell, texture and curd firmness.

Application of galactinol to tomato enhances tolerance to cold and heat stresses

Liu Yudong,Zhang Li,Ma Jian,Meng Sida,Pang Chunpeng,Zhao Xiaomeng,Zhang Huidong,Wang Shou,Xu Tao,He Yi,Liu Yufeng,Qi Mingfang 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.3

Galactinol, a galactosyl donor, is the key substrate in raffinose family oligosaccharide (RFO) biosynthesis pathways. Many studies proved that galactinol also regulates some defense-related genes to be transcribed as a sugar signal under biotic and abiotic stresses. There are four galactinol synthase (SlGolS) genes in tomato. In this study, SlGolS1, SlGolS2, and SlGolS4 responded to cold stress, especially SlGolS1 stems treated for 12 h and SlGolS4 stems treated for 24 h. Under heat stress, the expression levels of SlGolS1, SlGolS2, and SlGolS3, especially SlGolS1 and SlGolS2, increased in leaves, roots, and stems. When expressed in E. coli cells, SlGolS2 and SlGolS4 enhanced cold tolerance, whereas SlGolS1 and SlGolS3 improved heat tolerance. These results suggested that SlGolS family members played different roles in tolerance to cold and heat stresses. In addition, the application of galactinol or galactinol + α-galactosidase inhibitor (DGJ) improved the cold and heat tolerances of tomato plants, whereas the single application of DGJ had no effect. Interestingly, the applications of DGJ, galactinol, and galactinol + DGJ also affected the expression levels of SlRS, SlSTS, and SlAGAL under cold and heat stresses. These findings indicated that galactinol was involved in the biosynthesis pathways of RFOs as a galactosyl donor and regulated the expression levels of RFO biosynthesis and breakdown-related genes as a sugar signal under cold and heat stresses.

A Corpus-based Study on the Use of English Present Perfect by Chinese EFL Learners

( Liu Yi ) 대한언어학회 2016 언어학 Vol.24 No.2

Through the comparison of the corpora of LOCNESS and CLEC, this study examines Chinese EFL learners’ unique features in using English present perfect. It shows that Chinese learners are more obsessed with using resultative perfect compared with native speakers (p<.05). And Chinese learners use more experiential perfect along with their rising English proficiency, and there is a huge gap between different proficient learners (p<.05). With respect to persistent and recent perfect, both native and non-native speakers marginally used them. Chinese learners’ performance may be influenced by many factors such as L1/L2 interference, typicality of target language, learners’ different English proficiency, and learners’ avoidance of using target language, and so on. This study hopes to provide some implications to the EFL teaching.

Dynamic Multi-peak MPPT for Photovoltaic Power Generation Under Local Shadows Based on Improved Mayfly Optimization

Yi Lingzhi,Shi Hao,Liu Jiangyong,Zhou Dongfang,Liu Ximeng,Zhu Jiang 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

The P-U curves of PV array panels under partial shading shows multi-peaked characteristics, therefore, conventional Maximum Power Point Tracking (MPPT) methods may fail or not be accurate enough. In this paper, a Chaos Mayfl y Optimization with Lévy Flight and Adaptive Algorithm (CMOFA) is proposed to track the maximum power points of PV arrays under partial shading. Firstly, sin chaos is used to initialize the population, then adaptive adjustment of inertia weights is introduced and the learning factor is changed to enhance the local search ability of the algorithm. Later in the operation of the algorithm, when the search falls into the local optimum, Lévy fl ight with induced variable step length is used to make the algorithm jump out of the local optimum and improve the local optimum avoidance ability of the mayfl y algorithm. The simulation results show that CMOFA is not only able to avoid local shading and dynamic shading changes, but also has a signifi cant improvement in convergence speed and search accuracy compared with conventional intelligent algorithms.

Rhodium-Catalyzed Highly Regioselective C-H Arylation of Imidazo[1,2-a]pyridines with Aryl Halides and Triflates

Yi Liu,Lin He,Guoqiang Yin,Guojie Wu,Yingde Cui 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflates has been reported. This process afforded a range of biaryl compounds in excellent yields and showed high activity and broad scope.

Study on an Improved PSO Algorithm and its Application for Solving Function Problem

Liu Yi 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.3

Particle swarm optimization(PSO) algorithm has the advantages of simplicity and easy implementation, but it exits the weaknesses of the being easy to fall into local minimum and premature convergence. In order to overcome these weaknesses of PSO algorithm, the inertia weight and learning factor are improved and the PSO algorithm is initialized by using chaotic optimization in order to propose an improved PSO(WLFCPSO) algorithm. In the proposed WLFCPSO algorithm, chaotic optimization strategy is used to initialize the parameters of PSO algorithm in order to obtain the more reasonable initialization parameters. The adaptive inertia weight adjustment strategy is used to control the adjustment ability of inertia weight in order to keep the diversity of the inertia weight. The dynamic linear adjustment strategy for learning factors is used to gradually reduce the cognitive ability of the individual and improve the global search ability of particles. In order to prove the effectiveness of the proposed WLFCPSO algorithm, several benchmark functions are selected. The experiment results show that the proposed WLFCPSO algorithm has the rapider convergence speed and higher solution precision for solving high-dimension function optimization problems.

Research of Building Load Optimal Scheduling Based on Multi-objective Estimation of Distributed Algorithm

Liu Jiankang,Lingzhi Yi,Yi Fang,Lin Jiahao,Li Wang,Fan Lǜ 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

In the centralized scheduling of multi-residents, the complexity of scheduling time will be greatly increased as the number of resident increases. In order to reduce the time complexity caused by centralized scheduling, a probability model based on the Time-of-use electricity tariff diff erence is proposed and applied to distributed estimation of the algorithm. According to the impact factor mechanism of the probability model of Time-of-use electricity tariff diff erence, not only the time complexity of centralized scheduling is reduced, but also the optimization of the algorithm will not fall into a local optimal situation. In the centralized scheduling model of building residents, the controllable load of residents and new energy are centralized. The consumption rate of new energy was improved by changing the new energy power supply mechanism. Under the conditions of ensuring the comfort of household electricity consumption, three objective functions of the model include: (a) to reduce the total daily electricity consumption, (b) to fl atten the peak-to-valley diff erence of daily electricity, (c) to decrease the discarded rate of new energy. The simulation of the calculation example verifi es the feasibility and eff ectiveness of the proposed method.