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.

ST6Gal-I Predicts Postoperative Clinical Outcome for Patients with Localized Clear-cell Renal Cell Carcinoma

Liu, Hai-Ou,Wu, Qian,Liu, Wei-Si,Liu, Yi-Dong,Fu, Qiang,Zhang, Wei-Juan,Xu, Le,Xu, Jie-Jie Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Hyperactivated ${\alpha}2$-6-sialylation on N-glycans due to overexpression of the Golgi enzyme ${\beta}$-galactoside: ${\alpha}2$-6-sialyltransferase (ST6Gal-I) often correlates with cancer progression, metastasis, and poor prognosis. This study was aimed to determine the association between ST6Gal-I expression and the risk of recurrence and survival of patients with localized clear-cell renal cell carcinoma (ccRCC) following surgery. We retrospectively enrolled 391 patients (265 in training cohort and 126 in validation cohort) with localized ccRCC underwent nephrectomy at a single center. Tissue microarrays were constructed for immunostaining of ST6Gal-I. Prognostic value and clinical outcomes were evaluated. High ST6Gal-I expression was associated with Fuhrman grade (p<0.001 and p=0.016, respectively) and the University of California Los-Angeles Integrated Staging System (UISS) score (p=0.004 and p=0.017, respectively) in both cohorts. Patients with high ST6Gal-I expression had significantly worse overall survival (OS) (p<0.001 and p<0.001, respectively) and recurrence free survival (RFS) (p<0.001 and p=0.002, respectively) than those with low expression in both cohorts. On multivariate analysis, ST6Gal-I expression remained associated with OS and RFS even after adjusting for the UISS score. Stratified analysis suggested that the association is more pronounced among patients with low and intermediate-risk disease defined by the UISS score. High ST6Gal-I expression is a potential independent adverse predictor of survival and recurrence in ccRCC patients, and the prognostic value is most prominent in those with low and intermediate-risk disease defined by the UISS score.

Function and Accuracy of Lexical Bundle Use in English as L3 Learners' Essay Writings: A Learner Corpus-Based Study

Liu Yi,김양희 미래영어영문학회 2022 영어영문학 Vol.27 No.4

This study aims to investigate English features of lexical bundles used by English L3 group of learners, focusing on the function and accuracy. English L3 learners are Chinese Korean ethnic college students who acquired Korean and Chinese before learning English. In order to carry out a comprehensive comparison, Korean L1 and Chinese L1 students are also involved. Thus, EFL leaner corpora of Yonsei English Learner Corpus (YELC), Chinese Korean English Learner Corpus (CKELC), and Chinese Han English Learner Corpus (CHELC) are examined and compared, with Louvain Corpus of Native English Essay (LOCNESS) as a reference. By comparing those corpora, this study produced the following findings: (1) among the most frequently used bundles, English L3 learners used over 50% of the same bundles as Chinese L1 learners; (2) English L3 learners have the same preference as Korean L1 learners in overusing stance-expression bundles; (3) three groups of EFL learners had a better grammatical correctness than semantic appropriacy in terms of bundle use, but none of them had gained a satisfying performance; (4) with respect to the overall quality of lexical bundles, English L3 learners were the worst among the three EFL learner groups. The results of this study may provide pedagogical implications for EFL teachers to improve learners’ essay writing.

Expression and Prognostic Implications of FOXO3a and Ki67 in Lung Adenocarcinomas

Liu, Hong-Bin,Gao, Xiang-Xiang,Zhang, Qing,Liu, Jian,Cui, Yuan,Zhu, Yan,Liu, Yi-Fei Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4

To investigate the significance of FOXO3a and Ki67 in human lung adenocarcinomas. Envision immunohistochemical staining and Western blotting were used to examine the protein expression of FOXO3a in 127 cases of human lung adenocarcinoma specimens. The positive rate in lung adenocarcinoma (55.9%) was lower than that in normal tissues (80%). We found that the expression of FOXO3a was closely related with the degree of differentiation, TNM staging, lymph node metastasis and survival. In addition, significant differences in the different pathological types of lung adenocarcinoma cases (P<0.01). The FOXO3a positive rate of the acini as the main type (APA) (86.7%) and the lepidic as the main type (LPA) (82.4%) was higher than the solid as the main type (SPA) (50.0%), the papilla as the main type (PPA) (42.9%) and the micropapilla as the main type (MPA) (9.4%). Moreover, the expression of FOXO3a was negatively related with Ki67 expression. Our results suggested that the expression of FOXO3a is closely correlated with the aggressiveness of lung adenocarcinoma. It was indicated that disregulation of FOXO3a might play key roles in the occurrence and development of lung a denocarcinoma and joint detection of the two markers might play an important role in diagnosing tumors.

Cat

Liu Yi Cheng 한국콘텐츠학회 2023 ICCC International Digital Design Invitation Exhib Vol.2023 No.12

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.

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.

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.