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.

RNA m5C modification upregulates E2F1 expression in a manner dependent on YBX1 phase separation and promotes tumor progression in ovarian cancer

Liu Xiaoyi,Wei Qinglv,Yang Chenyue,Zhao Hongyan,Xu Jie,Mobet Youchaou,Luo Qingya,Yang Dan,Zuo Xinzhao,Chen Ningxuan,Yang Yu,Li Li,Wang Wei,Yu Jianhua,Xu Jing,Liu Tao,Yi Ping 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

5-Methylcytosine (m5C) is a common RNA modification that modulates gene expression at the posttranscriptional level, but the crosstalk between m5C RNA modification and biomolecule condensation, as well as transcription factor-mediated transcriptional regulation, in ovarian cancer, is poorly understood. In this study, we revealed that the RNA methyltransferase NSUN2 facilitates mRNA m5C modification and forms a positive feedback regulatory loop with the transcription factor E2F1 in ovarian cancer. Specifically, NSUN2 promotes m5C modification of E2F1 mRNA and increases its stability, and E2F1 binds to the NSUN2 promoter, subsequently reciprocally activating NSUN2 transcription. The RNA binding protein YBX1 functions as the m5C reader and is involved in NSUN2-mediated E2F1 regulation. m5C modification promotes YBX1 phase separation, which upregulates E2F1 expression. In ovarian cancer, NSUN2 and YBX1 are amplified and upregulated, and higher expression of NSUN2 and YBX1 predicts a worse prognosis for ovarian cancer patients. Moreover, E2F1 transcriptionally regulates the expression of the oncogenes MYBL2 and RAD54L, driving ovarian cancer progression. Thus, our study delineates a NSUN2-E2F1-NSUN2 loop regulated by m5C modification in a manner dependent on YBX1 phase separation, and this previously unidentified pathway could be a promising target for ovarian cancer treatment.

A Corpus-Based Study on Lexical Bundles in English Writings of Chinese Korean Minority College Students

( Yi Liu ),( Yang-Hee Kim ) 대한영어영문학회 2022 영어영문학연구 Vol.48 No.4

This study aims to explore how Chinese Korean minority college students use English lexical bundles in their writings. Four English written corpora of LOCNESS, YELC, CKELC, and CHELC were involved in this study, all the corpora were constructed by collecting college students’ timed and untimed essays. Not only English native students’ writings but three groups of EFL students’ writings were investigated. The four-word English lexical bundles extracted from each corpus were adopted as the data. By examining students’ actual writing, it found that Chinese Korean students overused lexical bundles with attitudinal expressions, and the same phenomenon was identified in L1 Korean students’ writings but not in Ll Chinese students’. The EFL students of L1 Korean, L1 Chinese and Chinese Korean all overused colloquial bundles and they all tended to use the same bundle types repeatedly. Compared with bundle tokens, all EFL students used a limited number of bundle types. In terms of lexical bundle structure, Chinese Korean students and L1 Chinese students preferred using prepositional bundles most, whereas L1 Korean students relied heavily on verbal bundles. All three EFL group students overused verbal bundles but underused nominal bundles. It is suggested that the EFL learners need to be exposed to a variety of lexical bundles.

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.

Elastography for Breast Cancer Diagnosis: a Useful Tool for Small and BI-RADS 4 Lesions

Liu, Xue-Jing,Zhu, Ying,Liu, Pei-Fang,Xu, Yi-Lin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

The present study aimed at evaluating and comparing the diagnostic performance of B-mode ultrasound (US), elastography score (ES), and strain ratio (SR) for the differentiation of breast lesions. This retrospective study enrolled 431 lesions from 417 in-hospital patients. All patients were examined with both conventional ultrasound and elastography. Two experienced radiologists reviewed ultrasound and elasticity images. The histopathologic result obtained from ultrasound-guided core biopsy or operation excisions were used as the reference standard. Pathologic examination revealed 276 malignant lesions (64%) and 155 benign lesions (36%). A cut-off point of 4.15 (area under the curve, 0.891) allowed significant differentiation of malignant and benign lesions. ROC (receiver-operating characteristic) curves showed a higher value for combination of B-mode ultrasound and elastography for the diagnosis of breast lesions. Conventional ultrasound combined elastography showed high sensitivity, specificity, and accuracy for group II lesions (10mm<lesion diameter ${\leq}20mm$). Elastography combined with conventional ultrasound show high specificity and accuracy for differentiation of benign and malignant breast lesions. Elastography is particularly important for the diagnosis of BI-RADS 4 and small breast lesions.

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.

Distributed Space-Time Coding for Full-Duplex Asynchronous Cooperative Communications

Yi Liu,Xiang-Gen Xia,Hailin Zhang IEEE 2012 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.11 No.7

<P>In this paper, we propose two distributed linear convolutional space-time coding (DLC-STC) schemes for full-duplex (FD) asynchronous cooperative communications. The DLC-STC Scheme 1 is for the case of the complete loop channel cancellation, which achieves the full asynchronous cooperative diversity. The DLC-STC Scheme 2 is for the case of the partial loop channel cancellation and amplifying, where some loop signals are used as the self-coding instead of treated as interference to be directly cancelled. We show this scheme can achieve full asynchronous cooperative diversity. We then evaluate the performance of the two schemes when loop channel information is not accurate and present an amplifying factor control method for the DLC-STC Scheme 2 to improve its performance with inaccurate loop channel information. Simulation results show that the DLC-STC Scheme 1 outperforms the DLC-STC Scheme 2 and the delay diversity scheme if perfect or high quality loop channel information is available at the relay, while the DLC-STC Scheme 2 achieves better performance if the loop channel information is imperfect.</P>

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.