Screening and Anti-virulent Study of N-Acyl Homoserine Lactones DNA Aptamers against Pseudomonas aeruginosa Quorum Sensing

Zu-Guo Zhao,Yun Mei Yu,Bi Yu Xu,Shuang-Shuang Yan,Jun-Fa Xu,Fang Liu,Guo-Ming Li,Yuan Lin Ding,Shu Qing Wu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

In Pseudomonas aeruginosa, a quorum sensing (QS) system regulates the expression of many virulence factors. N-acyl homoserine lactone (HSL) is the signal molecule of QS system. In order to find a novel HSL binder to interfere with QS signaling and to attenuate P. aeruginosa virulence, an amino lactam surrogate (ALS) of HSL was used as a target to screen HSL aptamers with the technique of systematic evolution of ligands by exponential enrichment (SELEX). Eight HSL aptamers with high affinities for 3O-C12-HSL (20 nM ≤ Kd < 35 nM) or C4-HSL (25 nM < Kd < 50 nM) were finally obtained. In vitro QS-inhibiting study of P. aeruginosa showed that HSL aptamers could inhibit virulence in a dose-dependent manner. ALSap-8 which bound C4-HSL primarily acted on the rhl system and inhibited the secretion of pyocyanin. ALSap-5 which bound 3O-C12-HSL not only showed strong inhibitory activity on biofilm formation as well as secretions of LasA protease and LasB elastase, but also reduced pyocyanin secretion. Since the las system is capable of activating the rhl system mildly, we speculated that ALSap-5 can simultaneously interfere with the las and rhl systems. High-affinity aptamers against HSL in this study are novel QS and virulence-inhibitors, and may have potential as drug candidates for the treatment of P. aeruginosa infection.

An Aqueous Extract of Yunnan Baiyao Inhibits the Quorum-Sensing-Related Virulence of Pseudomonas aeruginosa

Zu-Guo Zhao,Shuang-Shuang Yan,Yun-Mei Yu,Na Mi,La-Xi Zhang,Jun Liu,Xiao-Ling Li,Fang Liu,Jun-Fa Xu,Wei-Qing Yang,Guo-Ming Li 한국미생물학회 2013 The journal of microbiology Vol.51 No.2

Yunnan Baiyao is a famous Chinese medicine that has long been directly applied to wounds to reduce bleeding, pain, and swelling without causing infection. However, little is known about its ability to prevent infection. The present study aimed to assess in vitro the anti-virulence activity of an aqueous extract of Yunnan Baiyao (YBX) using Pseudomonas aeruginosa as a pathogenic model. We found that a sub-MIC (2.5 mg/ml) of YBX can efficiently interfere with the quorum-sensing (QS) signaling circuit. Real-time polymerase chain reaction analysis showed that a sub-MIC of YBX downregulated the transcriptions of lasR, lasI, rhlR, and rhlI,which resulted in global attenuation of QS-regulated virulence activities, such as biofilm formation, and secretion of LasA protease, LasB elastase and pyocyanin. Further, YBX reduced the motility of P. aeruginosa related to QS, and impaired the formation of biofilms. These results suggest that YBX may possess global inhibitory activity against the virulence of P. aeruginosa and that YBX may also exhibit antimicrobial activity in vivo. The present study suggests that Yunnan Baiyao represents a potential source for isolating novel, safe, and efficacious antimicrobial agents.

PERMANENCE OF A TWO SPECIES DELAYED COMPETITIVE MODEL WITH STAGE STRUCTURE AND HARVESTING

XU, CHANGJIN,ZU, YUSEN Korean Mathematical Society 2015 대한수학회보 Vol.52 No.4

In this paper, a two species competitive model with stage structure and harvesting is investigated. By using the differential inequality theory, some new sufficient conditions which ensure the permanence of the system are established. Our result supplements the main results of Song and Chen [Global asymptotic stability of a two species competitive system with stage structure and harvesting, Commun. Nonlinear Sci. Numer. Simul. 19 (2001), 81-87].

Morphogenesis and global analysis of transcriptional profiles of Celastrus orbiculatus aril: unravelling potential genes related to aril development

Kuiling Zu,Jianxia Li,Shubin Dong,Yunyu Zhao,Shenjian Xu,Zhixiang Zhang,Liangcheng Zhao 한국유전학회 2017 Genes & Genomics Vol.39 No.6

As a specialized seed appendage, the aril is a noteworthy and taxonomically important feature of Celastrus orbiculatus; the aril also has important ornamental value and biological functions. To better understand the mechanism of aril development, paraffin sections were used to examine its morphogenesis, and RNA-sequencing (RNA-seq) technology was employed for transcriptional profiling of the developing aril. Our results revealed that the aril of C. orbiculatus was formed by the cells of the exostomal region of the outer integument. By analyzing global changes in the transcriptome, 41,560,806, 42,789,340, and 44,496,748 clean reads from three cDNA libraries were generated and assembled into 87,600 unigenes with N50 of 1328 bp, in which 31,971 (36.49%) were annotated to Nr database. Furthermore, a total of 25,914 (29.79%), 14,394 (16.4%) and 11,957 (13.65%) genes were successfully annotated with hierarchical 48 GO terms, 26 KOGs and 32 KEGG pathways. Totally, 104, 1887 and 1967 differently expressed genes were identified in CO-F2 versus CO-F3, CO-F2 versus CO-YF1 and CO-F3 versus CO-YF1, respectively. GO and KEGG pathway analyses of DEGs involved in cell–cell communication and plant hormone signal transduction contributed to aril development were identified. Furthermore, we found putative key target genes of WRKY, Aux/IAA, ARF and MADS-box family’s transcription factors related to aril development. Real-time qPCR was performed on eight genes randomly selected from important transcription factors to validate the expression profiles obtained by RNA-seq. This work provides a platform for future genetic and functional genomics research on the molecular mechanisms of aril structure, and expands our understanding of the molecular mechanism and evolutionary analysis of aril development in other members of the Celastraceae.

Effect of Temperature and Strain Rate on the Hot Deformation Behaviour of Ferritic Stainless Steel

Guoqing Zu,Yukuan Lu,Yi Yan,Xiaoming Zhang,Jingwei Zhao,Wei Du,Xu Ran,Zhengyi Jiang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

The fow behaviour and microstructure characteristics of a ferritic stainless steel were investigated using plain strain compression test on a Gleeble 3500 thermo-mechanical test simulator with a hydrawedge system in the temperature range of850–1100 °C and strain rate range of 0.1–50 s−1. The phenomenological constitutive model and the relationship betweenthe Zener–Hollomon (Z) parameter and fow stress were established. The results reveal that the fow softening phenomenonoccurs at high strain rate, which is caused by the coupling efect of the adiabatic heating and dynamic recrystallisation (DRX). New grains nucleate preferentially at the original grain boundaries by strain-induced grain boundary migration. With anincrease of temperature or strain rate, a part of new grains form in the interior of deformed grains. The DRX grain size andfraction increase with the increase of temperature, however, exhibit a non-linear relationship with strain rate.

PERMANENCE OF A TWO SPECIES DELAYED COMPETITIVE MODEL WITH STAGE STRUCTURE AND HARVESTING

Changjin Xu,Yusen Zu 대한수학회 2015 대한수학회보 Vol.52 No.4

In this paper, a two species competitive model with stage structure and harvesting is investigated. By using the differential inequality theory, some new sufficient conditions which ensure the permanence of the system are established. Our result supplements the main results of Song and Chen [Global asymptotic stability of a two species competitive system with stage structure and harvesting, Commun. Nonlinear Sci. Numer. Simul. 19 (2001), 81–87].

<高等官话华语精选> 중국어 한글 표기법 연구: 성모를 중심으로

서춘란 ( Xu Chunlan ),주웨 ( Zu Yue ) 서강대학교 언어정보연구소 2023 언어와 정보 사회 Vol.49 No.-

The Qing and Ming Dynasties were critical periods in the maturation of the Beijing dialect. From the perspective of the history of the Chinese language, it was an important period of inheritance and succession. As the period of the Imperial Japanese occupation was in this period, it is of great significance to study Chinese textbooks of this time. This paper takes the Korean markers in the Korean textbook <高等官话华语精选> of the Japanese occupation period as the object of study, compiles and counts the Chinese consonant markers, and explores the characteristics of Korean markers at that time by comparing them with the current Sino-Korean markers. It ends by making some suggestions regarding the Sino-Korean markers.

Correlation between Intravoxel Incoherent Motion Magnetic Resonance Imaging Derived Metrics and Serum Soluble CD40 Ligand Level in an Embolic Canine Stroke Model

Xiao-Quan Xu,Chen-Jiang Wu,Shan-Shan Lu,Qian-Qian Gao,Qing-Quan Zu,Xing-Long Liu,Hai-Bin Shi,Sheng Liu 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.5

Objective: To determine the relationship between intravoxel incoherent motion (IVIM) imaging derived quantitative metrics and serum soluble CD40 ligand (sCD40L) level in an embolic canine stroke model. Materials and Methods: A middle cerebral artery occlusion model was established in 24 beagle dogs. Experimental dogs were divided into low- and high-sCD40L group according to serum sCD40L level at 4.5 hours after establishing the model. IVIM imaging was scanned at 4.5 hours after model establishment using 10 b values ranging from 0 to 900 s/mm2. Quantitative metrics diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) of ischemic lesions were calculated. Quantitative metrics of ischemic lesions were normalized by contralateral hemisphere using the following formula: normalized D = Dstroke / Dcontralateral. Differences in IVIM metrics between the low- and high-sCD40L groups were compared using t test. Pearson’s correlation analyses were performed to determine the relationship between IVIM metrics and serum sCD40L level. Results: The high-sCD40L group showed significantly lower f and normalized f values than the low-sCD40L group (f, p < 0.001; normalized f, p < 0.001). There was no significant difference in D*, normalized D*, D, or normalized D value between the two groups (All p > 0.05). Both f and normalized f values were negatively correlated with serum sCD40L level (f, r = -0.789, p < 0.001; normalized f, r = -0.823, p < 0.001). However, serum sCD40L level had no significant correlation with D*, normalized D*, D, or normalized D (All p > 0.05). Conclusion: The f value derived from IVIM imaging was negatively correlated with serum sCD40L level. f value might serve as a potential imaging biomarker to assess the formation of microvascular thrombosis in hyperacute period of ischemic stroke.

Follow-Up of 58 Traumatic Carotid-Cavernous Fistulas after Endovascular Detachable-Balloon Embolization at a Single Center

Xiao-Quan Xu,Sheng Liu,Qing-Quan Zu,Lin-Bo Zhao,Jin-Guo Xia,Chun-Gao Zhou,Wei-Zhong Zhou,Hai-Bin Shi 대한신경과학회 2013 Journal of Clinical Neurology Vol.9 No.2

Background and Purpose This study evaluated the clinical value of detachable-balloon embolization for traumatic carotid-cavernous fistula (TCCF), focusing on the frequency, risk factors, and retreatment of recurrence. Methods Fifty-eight patients with TCCF underwent transarterial detachable-balloon embolization between October 2004 and March 2011. The clinical follow-up was performed every 3months until up to 3 years postprocedure. Each patient was placed in either the recurrence group or the nonrecurrence group according to whether a recurrence developed after the first procedure. The relevant factors including gender, fistula location, interval between trauma and the interventional procedure, blood flow in the carotid-cavernous fistula, number of balloons, and whether the internal carotid artery (ICA) was sacrificed were evaluated. Results All 58 TCCFs were successfully treated with transarterial balloon embolization, including 7 patients with ICA sacrifice. Recurrent fistulas occurred in seven patients during the follow-up period. Univariate analysis indicated that the interval between trauma and the interventional procedure (p=0.006) might be the main factor related to the recurrence of TCCF. The second treatments involved ICA sacrifice in two patients, fistula embolization with balloons in four patients, and placement of a covered stent in one patient. Conclusions Detachable balloons can still serve as the first-line treatment for TCCFs and recurrent TCCFs despite having a nonnegligible recurrence rate. Shortening the interval between trauma and the interventional procedure may reduce the risk of recurrence.

Sensor-less external force detection for industrial manipulators to facilitate physical human-robot interaction

Bitao Yao,Zu-De Zhou,Lihui Wang,Wenjun Xu,Quan Liu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

Sensor-less external force detection is important for industrial robots which are usually not equipped with external force sensors to be applied in physical human-robot interaction (pHRI). This paper adopts the dynamic models of the robot in both dynamic mode and quasistatic mode to detect the external force. In the dynamic mode, the inertia and friction parameters of the robot are identified with the weighted least squares. The excitation trajectory for parameter identification is optimised. The un-modelled peak points in the joint torque residual are removed by a statistical method. The torque changes of joints in quasi-static mode which are equivalent to the joint pre-sliding friction is modelled with a lumped parameter model, generalised Maxwell slip (GMS) element model. Therefore, there is no need for the switching between the friction models in different modes and this and facilitates the application of dynamic model in the external force detection. The dynamic models of robots both in dynamic mode and quasi-static mode and their effectiveness for external force detection in pHRI are verified by experimental results.