Proliferation, Accumulation of Polyphenols, and Antioxidant Activities of Callus from the ‘Anji Baicha’ Cultivar of Tea [Camellia sinensis (L.) O. Ktze.]

Mingfei Liu,Junli Wang,Birui Tian,Jingjing Huang,Rongrong Zhang,Yuxing Lin,Zefeng Xiao 한국원예학회 2017 원예과학기술지 Vol.35 No.2

Tea is one of the most consumed beverages worldwide and the relatively high levels polyphenols is benefit for health. In this study, we developed an efficient system for proliferation of callus from ‘Anji Baicha’, a cultivar of tea (Camellia sinensis ). Callus tissue was initially induced by culturing leaf explants on medium containing different plant growth regulators. For callus induction, thidiazuron (TDZ) was more effective than 2,4-dichlorophenoxyacetic acid (2,4-D), α-naphthalene acetic acid (NAA), and N6-benzyladenine (BA). The frequency of callus induction from leaf explants reached 90.21% on 1.0 mg·L<SUP>-1</SUP> TDZ and the developed callus was reddish and friable. We also tested the effect of different concentrations of NAA, 2,4-D, indole 3-acetic acid (IAA), BA, and TDZ, alone and in combinations, on callus proliferation. Medium supplemented with TDZ in combination with IAA was suitable for callus proliferation and accumulation of tea polyphenols. The growth index value and tea polyphenol content of callus cultured on MS medium containing 0.5 mg·L<SUP>-1</SUP> TDZ and 1.0 mg·L<SUP>-1</SUP> IAA was maximally 1,351% and 23.24%, respectively, and the relative abundance of epicatechin was as high as 17.449%. We also measured the antioxidant activity of all samples and the callus with the highest tea polyphenol content also exhibited high potential radical scavenging activity.

Proliferation, Accumulation of Polyphenols, and Antioxidant Activities of Callus from the 'Anji Baicha' Cultivar of Tea [Camellia sinensis (L.) O. Ktze.]

Liu, Mingfei,Wang, Junli,Tian, Birui,Huang, Jingjing,Zhang, Rongrong,Lin, Yuxing,Xiao, Zefeng Korean Society of Horticultural Science 2017 원예과학기술지 Vol.35 No.2

Tea is one of the most consumed beverages worldwide and the relatively high levels polyphenols is benefit for health. In this study, we developed an efficient system for proliferation of callus from 'Anji Baicha', a cultivar of tea (Camellia sinensis). Callus tissue was initially induced by culturing leaf explants on medium containing different plant growth regulators. For callus induction, thidiazuron (TDZ) was more effective than 2,4-dichlorophenoxyacetic acid (2,4-D), ${\alpha}-naphthalene$ acetic acid (NAA), and $N^6-benzyladenine$ (BA). The frequency of callus induction from leaf explants reached 90.21% on $1.0mg{\cdot}L^{-1}$ TDZ and the developed callus was reddish and friable. We also tested the effect of different concentrations of NAA, 2,4-D, indole 3-acetic acid (IAA), BA, and TDZ, alone and in combinations, on callus proliferation. Medium supplemented with TDZ in combination with IAA was suitable for callus proliferation and accumulation of tea polyphenols. The growth index value and tea polyphenol content of callus cultured on MS medium containing $0.5mg{\cdot}L^{-1}$ TDZ and $1.0mg{\cdot}L^{-1}$ IAA was maximally 1,351% and 23.24%, respectively, and the relative abundance of epicatechin was as high as 17.449%. We also measured the antioxidant activity of all samples and the callus with the highest tea polyphenol content also exhibited high potential radical scavenging activity.

Image Encryption Research based on Key Extracted from Iris Feature

RuiYun Xie,MingFei Wang,BenZhai Hai 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.6

The encryption algorithm has disadvantages like the long key making memory difficult and uneasy safekeeping, which causes a potential threat to the information security. Therefore, a new direction of the encryption method research is to combine the biometric information with the traditional encryption algorithm. The key extracted from the iris and AES encryption algorithm are used in the image encryption algorithm. The db2 wavelet decomposition to the iris region is performed, and the third level high frequency coefficient is extracted as the iris feature codes, from which a 192 bit key is generated by using the stochastic mapping function. The randomness of the key extraction is analyzed. The proposed algorithm is employed to do the encryption test to the image. The encryption effect is compared with the scrambling encryption effect of the classic Arnold method. The experiment results show that security of the encryption image gained by using the proposed algorithm is higher, achieving the purpose of protecting image information.

Investigation of Capacitor Voltage Regulation in Modular Multilevel Converters with Staircase Modulation

Shen, Ke,Wang, Jianze,Zhao, Dan,Ban, Mingfei,Ji, Yanchao,Cai, Xingguo The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

This paper presents a detailed theoretical analysis and performance assessment of the capacitor voltage balancing strategies for staircase modulated modular multilevel converters (MMC) in terms of the algorithm structures, voltage balancing effect, and switching frequency. A constant-frequency redundancy selection (CFRS) method with minimal switching loss is proposed and the function realization of specific modules of the algorithm is given. This method is simple and efficient in both switching frequency and regulation capacity. Laboratory results show very good agreement with the theoretical analysis and numerical simulations.

Si–Ge alloys in C2/c phase with tunable direct band gaps: A comprehensive study

Qingyang Fan,Huiqin Wang,Wenzhu Zhang,Mingfei Wei,Yanxing Song,Wei Zhang,Sining Yun 한국물리학회 2019 Current Applied Physics Vol.19 No.12

Si–Ge alloys are a new type of semiconductor material that are of great significance for the development of microelectronic technology, especially in the photoelectricity industry and for thermoelectric conversion in high temperature applications (> 700 K). In the present work, a novel Ge allotrope in the C2/c phase with band gap of 1.102 eV was firstly proposed, which is suitable for the absorption of sunlight. C2/c-Ge are mechanically, dynamically and thermodynamically stable. A series of Si24-xGex alloys (x=0, 8, 16, 24) in the C2/c phase with band gaps of 1.10–1.50 eV are predicted by ab initio calculations at ambient conditions. The Si24-xGex alloys (x=0, 8, 16, 24) in C2/c phase have better absorption ability than that of the Si in diamond, hP12 and oC12 phases. The Si24-xGex alloys in the C2/c phase have the strong absorption in the visible, which have a great impact on the new-generation photovoltaic applications.

Investigation of Capacitor Voltage Regulation in Modular Multilevel Converters with Staircase Modulation

Ke Shen,Jianze Wang,Dan Zhao,Mingfei Ban,Yanchao Ji,Xingguo Cai 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

This paper presents a detailed theoretical analysis and performance assessment of the capacitor voltage balancing strategies for staircase modulated modular multilevel converters (MMC) in terms of the algorithm structures, voltage balancing effect, and switching frequency. A constant-frequency redundancy selection (CFRS) method with minimal switching loss is proposed and the function realization of specific modules of the algorithm is given. This method is simple and efficient in both switching frequency and regulation capacity. Laboratory results show very good agreement with the theoretical analysis and numerical simulations.

Identification of a 193 bp promoter region of TaNRX1‑D gene from common wheat that contributes to osmotic or ABA stress inducibility in transgenic Arabidopsis

Cheng Jie,Wei Fan,Zhang Mingfei,Li Nan,Song Tianqi,Wang Yong,Chen Dongsheng,Xiang Jishan,Zhang Xiaoke 한국유전학회 2021 Genes & Genomics Vol.43 No.9

Background Cloning and characterizing the drought-inducible promoters is essential for their use in crop resistance’s genetic improvement. Previous studies have shown that the TaNRX1-D gene participates in regulating the response of wheat to drought stress. However, its promoter has not yet been identifed. Objective In this study, we aimed to characterize the promoter of the TaNRX1-D gene. Methods The promoter of TaNRX1-D (named P0, 2081 bp) was isolated from common wheat with several cis-acting elements that regulate in response to abiotic stresses and some core cis-acting elements. Functional verifcation of the promoter, eight 5′-deletion fragments of TaNRX1-D promoter, was fused to the β-glucuronidase (GUS) gene P0::GUS~P7::GUS and transformed into Arabidopsis, respectively. Agrobacterium-mediated GUS transient assay the P6a and P6b promoter regions in tobacco leaves under normal, osmotic or ABA stress. Results Activity analysis of the full-length promoter (P0) showed that the intensity of stronger β-glucuronidase (GUS) staining in the roots and leaves was obtained during the growth of transgenic Arabidopsis. P0::GUS displayed the GUS activity was much higher in the roots and leaves than in other parts of the transgenic plant under normal conditions, which was similarly within wheat. Analysis of the 5′-deletion fragments revealed that P0::GUS~P6::GUS responded well upon exposure to osmotic (polyethylene glycol-6000, PEG6000) and abscisic acid (ABA) stress treatments and expressed signifcantly higher GUS activity than the CaMV35S promoter (35S::GUS), while P7::GUS did not. GUS transient assay in tobacco leaves showed that the GUS activities of P6a and P6b were lower than P6 in the PEG6000 and ABA stresses. Conclusion The 193 bp (P6) segment was considered the core region of TaNRX1-D responding to PEG6000 or ABA treatment. GUS activity assay in transgenic Arabidopsis showed that this segment was sufcient for the PEG6000 or ABA stress response. The identifed 193 bp promoter of TaNRX1-D in this study will help breed osmotic or ABA tolerant crops. The 36 bp segment between P6 and P6b (−193 to −157 bp) was considered the critical sequence for the TaNRX1-D gene responding to PEG6000 or ABA treatment.