Characterization of Cell Viability in Phaeocystis globosa Cultures Exposed to Marine Algicidal Bacteria

Xiaoli Hu,Pinghe Yin,Ling Zhao,Qiming Yu 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.1

The bloom of Phaeocystis globosa has occurredfrequently in the southern coastal areas of China in recentyears, which has led to substantial economic losses. Thisstudy investigated the effects of culture broth of strains Y1and Y4 isolated from algal blooms in Zhuhai, China onphysiological characteristics and cell viability of P. globosa. The increase in the levels of reactive oxygen species (ROS)in P. globosa cells exposed to strains Y1 and Y4 culturebroth were detected, indicating that the algal cells sufferedfrom oxidative damage. The surplus ROS induced theincrease of malondialdehyde (MDA) contents and theactivities of antioxidant enzymes, including superoxidedismutase (SOD) and catalase (CAT). The decrease inprotein content indicated that strains Y1 and Y4 culturebroth inhibited cell growth. The contents of pigmentsdecreased after 96 h treatment, indicated that oxidative stressdestroyed pigment synthesis. Furthermore, flow cytometrycoupled with the propidium iodide stain and chlorophyllauto-fluorescence was used to investigate cell viability. Results showed that chlorophyll fluorescence intensitiesand cell integrity decreased with time of exposure, whichdemonstrated that strains Y1 and Y4 culture broth couldchange membrane permeability and resulted in the loss ofthese photosynthetic pigments. The isolated strains wereidentified as Bacillus sp. by culture morphology, biochemicalreactions, and homology research based on 16S rDNA. Overall, these findings suggested that oxidative stress causedfrom Bacillus sp. potentially destroyed pigment synthesisand cell membrane integrity, and ultimately led to the lysisof the algal cells.

Event-triggered Stabilization of Linear Time-delay Systems by Static Output Feedback Control

Xiaoli Wang,Peng Xiang,Wenfeng Hu,Tingwen Huang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.11

In this paper, we study the stabilization problem for a class of linear systems with a time-varying state delay. An event-triggered static output feedback controller is proposed, such that the sampling frequency and the update time of the controller are both lowered. First, we present a novel event-triggering mechanism depending not only on the output but also on an exponential term, with which less sampling is required and Zeno behavior can be excluded at the same time. Some sufficient conditions are then obtained, under which an exponential convergence can be achieved by means of the comparison principle approach. It is further shown that the parameters design can be easily given if the case reduces to the state feedback control. Moreover, two examples are presented to show the effectiveness of the results.

Stability Analysis and Control of Nonlinear Behavior in V² Switching Buck Converter

Hu, Wei,Zhang, Fangying,Long, Xiaoli,Chen, Xinbing,Deng, Wenting The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

Mismatch between switching frequency and circuit parameters often occurs in industrial applications, which would lead to instability phenomena. The bifurcation behavior of $V^2$ controlled buck converter is investigated as the pulse width modulation period is varied. Nonlinear behavior is analyzed based on the monodromy matrix of the system. We observed that the stable period-1 orbit was first transformed to the period-2 bifurcation, which subsequently changed to chaos. The mechanism of the series of period-2 bifurcations shows that the characteristic eigenvalue of the monodromy matrix passes through the unit circle along the negative real axis. Resonant parametric perturbation technique has been applied to prevent the onset of instability. Meanwhile, the extended stability region of the converter is obtained. Simulation and experimental prototypes are built, and the corresponding results verify the theoretical analysis.

Stability Analysis and Control of Nonlinear Behavior in V² Switching Buck Converter

Wei Hu,Fangying Zhang,Xiaoli Long,Xinbing Chen,Wenting Deng 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

Mismatch between switching frequency and circuit parameters often occurs in industrial applications, which would lead to instability phenomena. The bifurcation behavior of V² controlled buck converter is investigated as the pulse width modulation period is varied. Nonlinear behavior is analyzed based on the monodromy matrix of the system. We observed that the stable period-1 orbit was first transformed to the period-2 bifurcation, which subsequently changed to chaos. The mechanism of the series of period-2 bifurcations shows that the characteristic eigenvalue of the monodromy matrix passes through the unit circle along the negative real axis. Resonant parametric perturbation technique has been applied to prevent the onset of instability. Meanwhile, the extended stability region of the converter is obtained. Simulation and experimental prototypes are built, and the corresponding results verify the theoretical analysis.

Isolation and characterization of heat-responsive gene TaGASR1 from wheat (Triticum aestivum L.)

Liyuan Zhang,Xiaoli Geng,Haiyan Zhang,Chunlei Zhou,Aiju Zhao,Fei Wang,Yue Zhao,Xuejun Tian,Zhaorong Hu,Mingming Xin,Yingyin Yao,Zhongfu Ni;Qixin Sun,Qixin Sun,Huiru Peng 한국식물학회 2017 Journal of Plant Biology Vol.60 No.1

GA-stimulated transcript (GAST) family genes have been identified in numerous plant species. In this paper, we isolated and characterized a heat-responsive gene, TaGASR1, from heat tolerant variety TAM107. The complete ORF of TaGASR1 was cloned, which encoded a 98-kDa protein, and the sequence shared 51.52% similarity to OsGASR1. Analysis of the TaGASR1 promoter region showed that it contained a heat shock element (HSE) and several cis-elements involved in abiotic stress response and hormone signal transduction. Expression patterns of TaGASR1 revealed that it was strongly induced by stress factors, such as high temperature, drought, high salinity and oxidation, as well as the phytohormones, including MeJA, ACC and ABA, which suggested the TaGASR1 gene might participate in these stress and hormone signal transduction pathways. Transient expression of TaGASR1-GFP fusion proteins in onion epidermal cells indicated that TaGASR1 protein was localized to the cell membrane or cytosol. Further analysis showed that ectopic expression of TaGASR1 in Arabidopsis enhanced thermotolerance and reduced the accumulation of reactive oxygen species (ROS) after heat stress. Moreover, we also found that TaGASR1-overexpressing wheat improved tolerance to heat stress and oxidative stress.

Expression profiles of genes involved in fatty acid and lipid biosynthesis in developing seeds of Paeonia ostii

Li Chaoqiong,Hu Lizong,Que Beibei,Hu Yueran,Guo Yuanyuan,Zhang Minghui,Wang Zenan,Wang Xueqin,Liu Hongzhan,Wang Junsheng,Tian Huihui,Li Xiaoli 한국유전학회 2021 Genes & Genomics Vol.43 No.8

Background Paeonia ostii seeds were identifed as novel sources of edible plant oil with a high proportion of α-linolenic acid, a type of n-3 fatty acid with many health benefts. Due to the unreliability of seed oil content and quality, it is necessary to discover the mechanism underlying lipid biosynthesis in Paeonia ostii seeds. Objectives This study aimed to identify the key genes involved in lipid biosynthesis in Paeonia ostii seeds by analyzing the relationship among the seed characteristics and the expression patterns of lipid genes in Paeonia ostii during seed development. Methods Preliminary research on Paeonia ostii seed development was carried out from 10 days after pollination until maturity, focusing on phenology, oil content and lipid profles. In addition, we investigated the spatiotemporal expression of 36 lipid biosynthetic genes in Paeonia ostii by using quantitative real-time PCR. Results The results suggested that the development of Paeonia ostii seeds from pollination to maturity could be divided into three periods. The 36 lipid genes showed various spatiotemporal expression patterns and fve gene groups with distinct temporal patterns during seed development were identifed by clustering analysis of expression data. Furthermore, the relationships between gene expression and lipid/fatty acid accumulation and some candidate key lipid genes were discussed. Conclusions This study provided the global patterns of fatty acid and lipid biosynthesis-related gene expression, which are critical to understanding the molecular basis of lipid biosynthesis and identifying the lipid accumulation rate-limiting genes during seed development.

Photosynthetic inhibition and oxidative stress to the toxic Phaeocystis globosa caused by a diketopiperazine isolated from products of algicidal bacterium metabolism

Shuo Tan,Xiaoli Hu,Pinghe Yin,Ling Zhao 한국미생물학회 2016 The journal of microbiology Vol.54 No.5

Algicidal bacteria have been turned out to be available for inhibiting Phaeocystis globosa which frequently caused harmful algal blooms and threatened to economic development and ecological balance. A marine bacterium Bacillus sp. Ts-12 exhibited significant algicidal activity against P. globosa by indirect attack. In present study, an algicidal compound was isolated by silica gel column, Sephadex G-15 column and HPLC, further identified as hexahydropyrrolo[1,2-a]pyrazine- 1,4-dione, cyclo-(Pro-Gly), by GC-MS and 1H-NMR. Cyclo-(Pro-Gly) significantly increased the level of reactive oxygen species (ROS) within P. globosa cells, further activating the enzymatic and non-enzymatic antioxidant systems, including superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and ascorbic acid (AsA). The increase in methane dicarboxylic aldehyde (MDA) content showed that the surplus ROS induced lipid peroxidation on membrane system. Transmission electron microscope (TEM) and flow cytometry (FCM) analysis revealed that cyclo-(Pro-Gly) caused reduction of Chl-a content, destruction of cell membrane integrity, chloroplasts and nuclear structure. Real-time PCR assay showed that the transcriptions of photosynthesis related genes (psbA, psbD, rbcL) were significantly inhibited. This study indicated that cyclo-(Pro-Gly) from marine Bacillus sp. Ts-12 exerted photosynthetic inhibition and oxidative stress to P. globosa and eventually led to the algal cells lysis. This algicidal compound might be potential bio-agent for controlling P. globosa red tide.

Amidoxime Functionalized Mesoporous SBA-15 with Various Mesostructures for Highly Efficient Concentration of U(VI)

Ziyan Yang,Xiaoli Yang,Rui Hu,Junfeng Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.2

Many current sorbents are limited for U(VI) concentration from aqueous solutions due to their inappropriate structures and surface chemistry. Herein, we report the rapid sorption of U(VI) with high capacities and selectivity by amidoxime modified ordered mesoporous SBA-15 with two typical morphologies (i.e., rods and plates) via a post-grafting method. Variables of the geochemical conditions (contact time, pH value, initial concentration, temperature and coexisting metal ions) are investigated. The results show that the mesostructures including morphologies and pore length of SBA-15 perform the dominant function for the fast sorption kinetics (10 min for plates, 20 min for rods), while the modified amidoxime groups make the excellent U(VI) sorption capacities (646.2 mg · g -1 for plates, 499.8 mg · g -1 for rods at pH 5.0 and T 298.15 K) and high selectivity possible. U(VI) adsorbed amidoxime-functionalized SBA can also be effectively regenerated by HCl solutions and reused well after six cycles.

Pharmacokinetic, metabolic stability, plasma protein binding and CYP450s inhibition/induction assessment studies of N-(2-pyridylmethyl)-2- hydroxiymethyl-1-pyrrolidinyl-4-(3-chloro-4-methoxy-benzylamino)-5- pyrimidine-carboxamide as potential type 5 phos

Haijun Qu,Xiaoxiao Hu,Xiaoli Shi,Chuan Wang,Longyuan Wang,Guoping Wang 한국통합생물학회 2019 Animal cells and systems Vol.23 No.3

N-(2-pyridylmethyl)-2-hydroxiymethyl-1-pyrrolidinyl-4-(3-chloro-4-methoxy-benzylamino)-5- pyrimidine-carboxamide (NHPPC) is a new potential of type 5 phosphodiesterase (PDE5) inhibitors, synthesized from the avanafil analogue for the treatment of erectile dysfunction. The targets of this article were to assess plasma protein binding, liver microsomal metabolic stability, inhibition and induction on cytochrome P450 isozymes and the pharmacokinetics of NHPPC. Equilibrium dialysis technique was applied to determine Plasma protein binding (PPB) and NHPPC was evaluated in male Sprague–Dawley rats and Beagle dogs in vivo pharmacokinetic. The NHPPC was highly bound to plasma proteins in rats, dogs and human tested and the mean values for PPB rate were 96.2%, 99.6% and 99.4%, respectively. After in vitro liver microsomes incubated for 60 min, the percent remaining of NHPPC was 42.8%, 0.8% and 42.0% in rats, dogs and human, respectively. In vitro intrinsic clearance was found to be 0.0233, 0.1204 and 0.0214 mL/min/mg protein in rat, dog and human liver microsomes of NHPPC, respectively. NHPPC showed no significant inhibitory effects on major CYP450 enzymes, and had no significant induction potential on CYP1A2 and CYP3A4. Following oral administration in rats and dogs, tmax was 6 and 0.5 h, respectively. The clearance for NHPPC was 1.19 and 1.46 L/h/kg in rats and dogs, respectively. And absolute bioavailability in rat and dog were approximately 34.5% and 53.1%, respectively. These results showed that NHPPC has a good development prospect.

MiR-214 inhibits apoptosis in thyroid epithelial follicular cells induced by amiodarone through the FASL/MAPK pathway

Wen Jing,Deng Chaonan,Shi Lixin,Zhou Shi,Zhang Miao,Hu Xiaoli,Wang Nianxue,Luo Lijuan 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.2

Background Hashimoto's thyroiditis (HT), also known as chronic lymphocytic thyroiditis, is one of the most common autoimmune disease (AITD) in clinical practice. It is urgent to explore the mechanism of amiodarone-induced thyroid dysfunction. Objective This study aims to assess the expression levels of miR-214 and FasL in amiodarone contact type of HT, and the effect of miR-214 on cell viability and apoptosis and potential mechanism. Results We found that miR-214 was low expressed in the tissues of amiodarone-treated thyroiditis patients. MiR-214 increased the survival rate of amiodarone-induced thyroid epithelial follicular cells and inhibited apoptosis. Mechanically, we found that miR-214 could bind to FASL and regulate MAPK signaling pathway through FASL. Conclusions Our results suggested that miR-214 could be a potential therapeutic target for Hashimoto's thyroiditis.