Fermentation Optimization and Industrialization of Recombinant Saccharopolyspora erythraea Strains for Improved Erythromycin A Production

Xiang Zou,Chang-fa Chen,Xia-chang Qi,Jiang-chao Qian,Ju Chu,Ying-ping Zhuang,Si-liang Zhang,Wei Zeng,Wan-jun Li 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.6

Improvement of Erythromycin A (Er-A) production and purity by metabolic engineering of the industrial erythromycin-producing strains Saccharopolyspora erythraea strians ZL1004 and ZL1007, in which the amounts of tailoring enzymes EryK (a P450 hydroxylase)and EryG (an S-adenosylmethionine-dependent O-methyltransferase)for biotransformation of Erythromycin D to Er-A were modulated, was performed in a 50 L fermentor. Addition of 15 g/L of corn steep liquor to the medium increased Er-A production; maximum Er-A production was 8,196 U/mL at 191 h, which was 81.8% higher than that of control (4,507 U/mL at 184 h). Er-B impurities were completely eliminated, whereas Er-C impurities were only 153 U/mL at 191 h. Analysis of intra- and extracellular metabolites and key enzyme activities in central carbon metabolism revealed that the pool of TCA cycle intermediates was enhanced by the addition of corn steep liquor and induced an increase in erythromycin biosynthesis. There were no significant differences between strains ZL1004 and ZL1007 regarding Er-A production and impurity accumulation. Compared to wild type strain,Er-A production was improved by 23.9% while Er-C was reduced by 83.9% and Er-B was completely eliminated. Furthermore, fermentation of recombinant strain ZL1004was successfully scaled up from laboratory scale (50 L fermentor) to industrial scale (25 and 132 m3), with similar levels of Er-A production and purity obtained.

Possible role of Pax-6 in promoting breast cancer cell proliferation and tumorigenesis

( Xiang Yun Zong ),( Hong Jian Yang ),( Yang Yu ),( De Hong Zou ),( Zhi Qiang Ling ),( Xiang Ming He ),( Xu Li Meng ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.9

Pax 6, a member of the paired box (Pax) family, has been implicated in oncogenesis. However, its therapeutic potential has been never examined in breast cancer. To explore the role of Pax6 in breast cancer development, a lentivirus based short hairpin RNA (shRNA) delivery system was used to knockdown Pax6 expression in estrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) breast cancer cells. Effect of Pax6 silencing on breast cancer cell proliferation and tumorigenesis was analyzed. Pax6-RNAi-lentivirus infection remarkably downregulated the expression levels of Pax6 mRNA and protein in MCF-7 and MDA-MB-231 cells. Accordingly, the cell viability, DNA synthesis, and colony formation were strongly suppressed, and the tumorigenesis in xenograft nude mice was significantly inhibited. Moreover, tumor cells were arrested at G0/G1 phase after Pax6 was knocked down. Pax6 facilitates important regulatory roles in breast cancer cell proliferation and tumor progression, and could serve as a diagnostic marker for clinical investigation. [BMB reports 2011; 44(9): 595-600]

Numerical simulation on the coupled chemo-mechanical damage of underground concrete pipe

Xiang-nan Li,Xiao-bao Zuo,Yu-xiao Zou,Yu-juan Tang 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.86 No.6

Long-termly used in water supply, an underground concrete pipe is easily subjected to the coupled action of pressure loading and flowing water, which can cause the chemo-mechanical damage of the pipe, resulting in its premature failure and lifetime reduction. Based on the leaching characteristics and damage mechanism of concrete pipe, this paper proposes a coupled chemo-mechanical damage and failure model of underground concrete pipe for water supply, including a calcium leaching model, mechanical damage equation and a failure criterion. By using the model, a numerical simulation is performed to analyze the failure process of underground concrete pipe, such as the time-varying calcium concentration in concrete, the thickness variation of pipe wall, the evolution of chemo-mechanical damage, the distribution of concrete stress on the pipe and the lifetime of the pipe. Results show that, the failure of the pipe is a coupled chemo-mechanical damage process companied with calcium leaching. During its damage and failure, the concentrations of calcium phase in concrete decrease obviously with the time, and it can cause an increase in the chemo-mechanical damage of the pipe, while the leaching and abrasion induced by flowing water can lead to the boundary movement and wall thickness reduction of the pipe, and it results in the stress redistribution on the pipe section, a premature failure and lifetime reduction of the pipe.

Molecular Cloning, Segmental Distribution and Ontogenetic Regulation of Cationic Amino Acid Transporter 2 in Pigs

Zou, Shi-geng,Zhi, Ai-min,Zhou, Xiang-yan,Zuo, Jian-jun,Zhang, Yan,Huang, Zhi-yi,Xu, Ping-Wen,Feng, Ding-yuan Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.5

The goal of this study was to elucidate the expression and segmental distribution of the glomerular cationic amino acid metabolism transporter-2 (CAT-2) and thus to improve our understanding of porcine cationic amino acid transporters and amino acid absorption. Porcine CAT-2 was cloned, sequenced and characterized. The predicted amino acid sequence of porcine CAT-2 shared 86.1% and 92.1% identity with human and mouse CAT-2A, respectively. The tissue distribution patterns and ontogenic changes of CAT-2 mRNAs were determined by real-time Q-PCR. The results showed that porcine CAT-2 was highly expressed in the heart and intestinal tract (duodenum, ileum and jejunum). In addition, the mRNA of CAT-2 was found in liver, lung, kidney, brain and muscle. Within the intestinal tract, CAT-2 mRNA was most abundant in the ileum and rarely expressed in the duodenum. In the duodenum, the levels of CAT-2 mRNA reached their peak on day 7 (p<0.05) while in the jejunum, levels were low on day 1 and 7 and increased rapidly after day 26 before peaking on days 30 and 60 (p<0.05). The levels then dramatically decreased by day 90 (p<0.05). In the ileum, levels achieved their maximum on day 30 and then decreased significantly on day 60 (p<0.05).

RESEARCH ON VIBRATION MODE LOCALIZATION OF LARGE ANTENNAS IN SATELLITES WITH SMALL DISORDER

Xiang-qiu LIU,Cong Wang,Wei-yuan WANG,Zhen-zhu ZOU 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

Theoretical study of UHPCC composite column behaviors under axial compression

Xiang-Guo Wu,Ruofei Zou,Xinyu Zhao,Qun Yu 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.5

To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.

Characterization of the complete chloroplast genome sequence of <i>Hypericum petiolulatum</i> (Hypericaceae)

ZOU Le,BAI Rui-Zhu,XIANG Chun-Lei,LI Lu 한국식물분류학회 2024 식물 분류학회지 Vol.54 No.1

<i>Hypericum</i> L. (Hypericaceae) is one of the best-selling herbal medicines in the world comprising ca. 500 species of herbs, shrubs, and small trees. <i>Hypericum petiolulatum</i> Hook. f. & Thomson ex Dyer is widely distributed in China, Vietnam, Myanmar, Nepal, India, Malaysia, and Bhutan and is used as a traditional herb to treat hemoptysis and inflammation. In this study, we sequenced and assembled the complete chloroplast (cp) genome of <i>H. petiolulatum</i>. The complete plastome of <i>H. petiolulatum</i> was 136,105 bp in length, with a large single copy region (LSC) of 93,709 bp, a small single copy region (SSC) of 11088 bp and two identical inverted repeats (IRs) of 15,654 bp. The overall GC content of the plastome was 37.0%, while GC contents of the LSC, SSC, and each IR were 35.5%, 31.0%, and 43.8%, respectively. In addition, 116 genes consisting of 76 protein-coding genes, six ribosomal RNA genes, and 34 transfer RNA genes were identified. A phylogenetic analysis of 14 taxa inferred based on cp genome sequences revealed a close relationship between <i>H. petiolulatum</i> and <i>H. perforatum</i>. The complete cp genome sequence of <i>H. petiolulatum</i> reported in this paper will facilitate population and phylogenomics studies of this medicinal plant group.

Optimization of Enzymatic Synthesis of L-ascorbyl Palmitate by Solvent Engineering and Statistical Experimental Designs

Xiang-Jun Jiang,Yi Hu,Ling Jiang,Bin Zou,Ping Song,He Huang 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

Statistical experimental designs combined with solvent engineering for optimization of enzymatic synthesis of L-ascorbyl palmitate were developed. First, the composition of the solvent for co-dissolving polar and apolar substrates was determined. The co-solvent mixture of tert-pentanol:DMSO at a ratio of 9:1 (v/v) and the optimal biocatalyst were obtained. Then, the Plackett-Burman design was implemented to screen the variables that significantly influence the conversion. The method of steepest ascent was used to approach the proximity of optimum. After determining the Plackett-Burman and steepest ascent designs, the optimum values were determined by central composite design under response surface methodology. The statistical analysis showed that the optimum reaction conditions (temperature 50oC, enzyme concentration 5.8 g/L,and substrate molar ratio 11:1, stirring rate 160 rpm, amount of molecular sieve 50 g/L, time 18 h) led to the maximum conversion (66.44%) and production concentration (20.63 g/L). A very satisfactory conversion (64.74%) and production concentration (20.13 g/L) could be achieved in short time (6 h).

Surface effects on flutter instability of nanorod under generalized follower force

Qiu-Xiang Xiao,Jiaqi Zou,이강용,Xian-Fang Li 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.64 No.6

This paper studies on dynamic and stability behavior of a clamped-elastically restrained nanobeam under the action of a nonconservative force with an emphasis on the influence of surface properties on divergence and flutter instability. Using the Euler-Bernoulli beam theory incorporating surface effects, a governing equation for a clamped-elastically restrained nanobeam is derived according to Hamilton‟s principle. The characteristic equation is obtained explicitly and the forcefrequency interaction curves are displayed to show the influence of the surface effects, spring stiffness of the elastic restraint end on critical loads including divergence and flutter loads. Divergence and flutter instability transition is analyzed. Euler buckling and stability of Beck‟s column are some special cases of the present at macroscale.

MiR-340 regulates the growth and metabolism of renal cell carcinoma cells by targeting frizzled class receptor 3

Mingfeng Xiang,Yanqun Huang,Changjun Dai,Gaode Zou 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.2

MicroRNA(miR)-340 is known as a multifunctionalmiRNA related to various types of cancer while itsrole in renal cell carcinoma (RCC) remains to be furtherinvestigated. In the present study, an apparent increase inmiR-340 expression was observed in both clear cell RCCtissues and RCC cell line 786-O and Caki-1. Functionally,the overexpression of miR-340 promoted cell proliferation,migration, invasion, extracellular alanine (Ala) level, andglycolysis level in 786-O cells. Then, frizzled class receptor3 (FZD3) was determined as the target gene of miR-340 andits expression level was negatively regulated by miR-340. The FZD3 silencing abrogated the inhibitory eff ect of miR-340 knockdown on cell proliferation, migration, invasion,Ala level, and glycolysis level in 786-O cells. In conclusion,miR-340 promotes proliferation, migration, and invasion ofRCC cells via suppressing FZD3 expression, and the promotioneff ect of miR-340 on RCC progression may be due to itsregulatory eff ect on glycolysis and Ala level.