THE SOLVABILITY CONDITIONS FOR A CLASS OF CONSTRAINED INVERSE EIGENVALUE PROBLEM OF ANTISYMMETRIC MATRICES

PAN XIAO-PING,HU XI-YAN,ZHANG LEI Korean Mathematical Society 2006 대한수학회지 Vol.43 No.1

In this paper, a class of constrained inverse eigenvalue problem for antisymmetric matrices and their optimal approximation problem are considered. Some sufficient and necessary conditions of the solvability for the inverse eigenvalue problem are given. A general representation of the solution is presented for a solvable case. Furthermore, an expression of the solution for the optimal approximation problem is given.

The solvability conditions for a class of constrained inverse eigenvalue problem of antisymmetric matrices

Xiao-ping Pan,Xi-yan Hu,Lei Zhang 대한수학회 2006 대한수학회지 Vol.43 No.1

In this paper, a class of constrained inverse eigenvalue problem for antisymmetric matrices and their optimal approximation problem are considered. Some sufficient and necessary conditions of the solvability for the inverse eigenvalue problem are given. A general representation of the solution is presented for a solvable case. Furthermore, an expression of the solution for the optimal approximation problem is given.

METTL3 promotes adriamycin resistance in MCF-7 breast cancer cells by accelerating pri-microRNA-221-3p maturation in a m6A-dependent manner

Pan Xiaoping,Hong Xiaolv,Li Sumei,Meng Ping,Xiao Feng 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Breast cancer (BC) is the most prevalent malignant neoplasm among women and is the fifth most common cause of cancer-associated death worldwide. Acquired chemoresistance driven by genetic and epigenetic alterations is a significant clinical challenge in treating BC. However, the mechanism of BC cell resistance to adriamycin (ADR) remains to be elucidated. In this study, we identified the methyltransferase-like 3/microRNA-221-3p/homeodomain-interacting protein kinase 2/Che-1 (METTL3/miR-221-3p/HIPK2/Che-1) axis as a novel signaling event that may be responsible for resistance of BC cells to ADR. A dual-luciferase reporter gene assay was employed to test the presence of miR-221-3p binding sites in the 3′UTR of HIPK2. Drug resistance was evaluated by immunoblotting multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP). Cultured ADR-resistant MCF-7 cells were assayed for their half maximal inhibitory concentration (IC50) values and apoptosis using an MTT assay and Annexin V-FITC/PI-labeled flow cytometry, and the cells were then xenografted into nude mice. METTL3 knockdown was shown to reduce the expression of miR-221-3p by reducing pri-miR-221-3p m6A mRNA methylation, thereby reducing the IC50 value of ADR-resistant MCF-7 cells, reducing the expression of MDR1 and BCRP, and inducing apoptosis. Mechanistically, miR-221-3p was demonstrated to negatively regulate HIPK2 and upregulate its direct target Che-1, thus leading to enhanced drug resistance in ADR-resistant MCF-7 cells. In vitro results were reproduced in nude mice xenografted with ADR-resistant MCF-7 cells. Our work elucidates an epigenetic mechanism of acquired chemoresistance in BC, in support of the METTL3/miR-221-3p/HIPK2/Che-1 axis as a therapeutic target for the improvement of chemotherapy.

Invited Review : Caenorhabditis elegans: A Model System for Anti-Cancer Drug Discovery and Therapeutic Target Identification

( Robert A Kobet ),( Xiao Ping Pan ),( Bao Hong Zhang ),( Stephen C Pak ),( Adam S Asch ),( Myon Hee Lee ) 한국응용약물학회 2014 Biomolecules & Therapeutics(구 응용약물학회지) Vol.22 No.5

The nematode Caenorhabditis elegans (C. elegans) offers a unique opportunity for biological and basic medical researches due to its genetic tractability and well-defined developmental lineage. It also provides an exceptional model for genetic, molecular, and cellular analysis of human disease-related genes. Recently, C. elegans has been used as an ideal model for the identification and functional analysis of drugs (or small-molecules) in vivo. In this review, we describe conserved oncogenic signaling pathways (Wnt, Notch, and Ras) and their potential roles in the development of cancer stem cells. During C. elegans germline development, these signaling pathways regulate multiple cellular processes such as germline stem cell niche specification, germline stem cell maintenance, and germ cell fate specification. Therefore, the aberrant regulations of these signaling pathways can cause either loss of germline stem cells or overproliferation of a specific cell type, resulting in sterility. This sterility phenotype allows us to identify drugs that can modulate the oncogenic signaling pathways directly or indirectly through a high-throughput screening. Current in vivo or in vitro screening methods are largely focused on the specific core signaling components. However, this phenotype based screening will identify drugs that possibly target upstream or downstream of core signaling pathways as well as exclude toxic effects. Although phenotype-based drug screening is ideal, the identification of drug targets is a major challenge. We here introduce a new technique, called Drug Affinity Responsive Target Stability (DARTS). This innovative method is able to identify the target of the identified drug. Importantly, signaling pathways and their regulators in C. elegans are highly conserved in most vertebrates, including humans. Therefore, C. elegans will provide a great opportunity to identify therapeutic drugs and their targets, as well as to understand mechanisms underlying the formation of cancer.

Molecular cloning of novel α-gliadin genes from Crithopsis delileana and the evolution analysis with those from Triticeae

Zhi-Fu Guo,Xiang-Yu Long,Pan Dong,Yu-Ming Wei,Li-Ping Bai,Xiao-Xuan Dang,Hao-Lei Wan,Li-Jun Zhang,You-Liang Zheng 한국유전학회 2011 Genes & Genomics Vol.33 No.2

The α-gliadins from Crithopsis delileana (Schult) Roshev (2n=2x=14, KK) were investigated by Acid polyacrylamide gel electrophoresis (A-PAGE) analysis. It was indicated that the electrophoresis mobility of gliadins from C.delileana had obvious difference with those from common wheat in α, γand ω region. Using primers designed from published sequences of α-gliadin genes, three α-gliadin genes were isolated from C. delileana, which were designated as gli-ka1,gli-ka2 and gli-ka3, respectively. Two in-frame stop codons were found in the coding sequences of gli-ka3, indicating that gli-ka3 could be a pseudogene. The gli-ka2 was a gliadin with an odd number of cysteines, resulting from a non-synonymous mutation. This change might lead to the interactive behavior of gli-ka2. Three α-gliadin genes of C. delileana had the similar but not identical primary structures to the corresponding gene sequences from other wheat related species. By the alignment of α-gliadin genes from Triticeae,phylogenetic analysis indicated that three α-gliadin genes of C. delileana clustered together with all α-gliadin genes from Ee genome of Lophopyrum elongatum by an interior paralleled branch.

Impact of Grafting Density on the Self-Assembly and Hydrophilicity of Succinylated Collagen

Wenxin Wang,Feiyi Shu,Lingyu Pan,Shanshan Huang,Xiao Tu,Ping Li,Siman Li,Yuanyuan Li,Chengzhi Xu,Yang Sun,Juntao Zhang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.6

Modification of protein could give their new functionality but would affect their intrinsic property and activity. In this paper, a series of succinylated collagen (SCol(n/1)) (n≥1) were prepared by modification of collagen with succinic anhydride at different molar ratio to amino groups amount of collagen. The impact of grafting density on the intrinsic self-assembly and additional hydrophilicity of succinylated collagen was explored. The results revealed that excessive grafting density of succinylated collagen would improve their hydrophilicity but weaken their self-assembly property, although the triple helix of collagen could be reserved after succinylation. SCol(1/1) (grafting density of 17%) with self-assembly property and good hydrophilicity was chosen to compare with native collagen. Compared to native collagen, thermostability of SCol(1/1) decreased slightly, however, SCol(1/1) could form softer hydrogel, which was more favorable for the proliferation of NIH/3 T3. The present work would help us to further understand the importance of grafting density for the design of modified collagen with intrinsic self-assembly property and additional new functionality.

Knockdown of glycogen phosphorylase and glycogen synthase influences expression of chitin synthesis genes of rice brown planthopper Nilaparvata lugens

Dao-Wei Zhang,Hui-Juan Wang,Xing Jin,Bi-Ying Pan,Bo-Ping Zeng,Zhong-Jiu Xiao,Cai-Di Xu,Bin Tang 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.3

Glycogen synthase (GS) and glycogen phosphorylase (GP) are two key enzymes in the glycogen synthesis pathway, which catalyze trehalose and glucose transformation in insects. GS and GP can be regulated by trehalose metabolism, which plays an important role in insect growth. However, it is not known whether these genes can be targeted for pest control through regulation of chitin metabolism. We studied the function of Nilaparvata lugens GS and GP (NLGS and NLGP, respectively) using RNA interference, and reported that trehalose and the chitin biosynthesis pathways are regulated by GP and GS, especially TPS3, TRE1-1, and G6PI1, which decreased following knockdown of these two genes. The expression levels of TPS1, TPS2, and several chitin synthesis pathway family genes were significantly increased following dsNlGP injection. Additionally, despite there being no apparent change to the chitin content, an abnormal molting phenotype and wing deformity appeared, and close to 25% insects died. These results demonstrate that silencing of NLGP or NLGS can lead to molting deformities and an elevated mortality rate through the regulation of chitin pathway genes and chitinase genes. NLGP may play a key role in chitin synthesis due to the number of genes regulated, and higher deformity and mortality rates resulting from its knockdown.

Investigation into performance enhancements of Li–S batteries via oxygen-containing functional groups on activated multi-walled carbon nanotubes using Fourier transform infrared spectroscopy

Yu Hai Wang,Zhe Dai,Chao Yue Zhang,Guo Wen Sun,Zhong Wei Lu,Xiu Ping Gao,Geng Zhi Sun,Wei Lan,Zhen Xing Zhang,Xiao Jun Pan,Jin Yuan Zhou 한국물리학회 2020 Current Applied Physics Vol.20 No.9

It was demonstrated that the electrochemical performance enhancements in KOH-activated carbon materials should be mainly due to the created polar oxygen-containing functional groups (OFGs, such as such as C–O, C–– O, –OH, and O–C–– O), while the role of each OFGs on the electrochemical enhancements is still unclear. In this work, KOH activation treatments were systematically conducted on carbon nanotubes (CNTs) to explore the role of each OFG on the performance enhancements of Li–S batteries (LSBs). Results showed that the capacity of activated-CNT-sulfur (a-CNT-S) cathodes is 33% higher than that of the pristine CNT-S cathodes, and their rate capability and cycling stability are also enhanced. And the electrochemical analysis combining with Fourier transform infrared spectroscopy indicated that the formed C–O bonds are the real factor for the enhanced electrochemical performances of a-CNT-S cathodes. Furthermore, the optimal activation conditions on CNTbased cathodes for LSBs were optimized to be 10 min at 700 ℃.