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Table of Content

    • Current Biotechnology
      Volume 11 Issue 3 25 May 2021
    • Research Progress in the Inhibitory Effects of Essential Oils on the Quorum Sensing System of Pseudomonas aeruginosa
    • ZENG Taohua1,2, LI Wenru1*, XIE Xiaobao1*, SHI Qingshan1, ZHANG Jianshe2
    • 2021, 11(3):  279-288.  DOI: 10.19586/j.2095-2341.2020.0165
    • Abstract ( ) PDF (1304KB)( )
      • Quorum sensing (QS) is a kind of communication mechanism between individual bacteria, which widely exists in bacteria. Pseudomonas aeruginosa is an opportunistic pathogen of human beings, which has at least three QS systems, namely las, rhl and pqs systems, and there is a cascade regulation relationship among them, which jointly regulate the expression of many virulence genes and the production of virulence factors. In recent years, it has become a new strategy to control the virulence and pathogenicity of P. aeruginosa for the treatment of this pathogen infection by inhibiting its QS systems. Plant essential oil is a natural quorum sensing inhibitors (QSI). Many active compounds of essential oil can inhibit the QS system of P. aeruginosa, and no drug resistance has been found in bacteria. Based on this, the composition and cascade regulation of QS system of P. aeruginosa were carded, the QS inhibition mechanism and inhibitory activity of plant essential oils were briefly introduced, and the research progress in the inhibitory effects of terpenoids, aromatic compounds, aliphatic compounds and sulfur-containing and nitrogen-containing compounds on QS system of P. aeruginosa was emphatically reviewed, in order to provide reference for the related research of finding and screening safe and efficient bacterial QSI from natural compounds, and lay a theoretical foundation for the prevention and control of pathogenic bacteria.
    • Progress on Plant Endoplasmic Reticulum Stress
    • ZHANG Rongxue§, SUN Yue§, SU Jingping, WANG Shengjun, LIU Yanqing, TONG Hui, SUN Linjing*
    • 2021, 11(3):  289-297.  DOI: 10.19586/j.2095-2341.2020.0147
    • Abstract ( ) PDF (3030KB)( )
      • Endoplasmic reticulum (ER) is an important site for protein folding and protein glycosylation. There are many regulatory mechanisms in endoplasmic reticulum to ensure that the proteins are correctly folded, modified and assembled to maintain the endoplasmic reticulum steady state, which is very important for the normal physiological activities of cells. However, many physical and chemical factors can make the endoplasmic reticulum out of balance, that is, under stress conditions, the accumulation of misfolded and unfolded protein will lead to endoplasmic reticulum stress (ERS), which will lead to unfolded protein response (UPR), and in extreme cases, it will also initiate program cell death (PCD). At present, the research on endoplasmic reticulum stress in plants lags behind that in yeast and animals. Therefore, the existing research on endoplasmic reticulum stress in plants was reviewed from two aspects: endoplasmic reticulum quality control system and unfolded protein response, in order to provide references for further understanding the relationship between endoplasmic reticulum stress and plant stress.
    • Study on Changes of Nutritional Components and Processing Characteristics of Ganoderma lucidum Fermented Corn
    • LEI Tongtong1, WANG Lihua1, WU Yuanyuan2, CHEN Yanfei3, TANG Xuanming1*
    • 2021, 11(3):  322-329.  DOI: 10.19586/j.2095-2341.2020.0150
    • Abstract ( ) PDF (2221KB)( )
      • As the main coarse cereals, corn has high nutritional value, rich in vitamins and dietary fiber, which can prevent a variety of sub-health diseases and is favored by the market. However, the unbalanced nutritional structure and poor processability of corn flour limit its application. Studies have shown that microbial fermentation technology can improve the nutritional composition, macromolecular structure and processing characteristics of grains. Based on this, corn was used as a solid medium fermented by Ganoderma lucidum to obtain the G. lucidum fermented corn (GFC), refer to as fungus fermented cereal (FFC) in this research, and the nutritional composition, macromolecular structure and processing characteristics of FFC were evaluated. The results showed that compared with unfermented corn, the contents of carbohydrate and protein in FFC increased by 7.48% and 28.00%, respectively, and the amino acid score of protein increased, while the fat content decreased by 5256%. The contents of vitamin C, riboflavin and nicotinic acid increased significantly (P<0.05), by 56.19%, 73.91% and 20.27%, respectively, and thiamine, which was deficient in corn, was detected in FFC. The contents of starch and fiber in FFC also changed significantly (P<0.05), starch and amylopectin decreased by 11.17% and 34.70%, amylose increased by 26.66%, crude fiber and insoluble dietary fiber decreased by 21.07% and 21.47%, and soluble dietary fiber increased by 13.57%. The viscosity of FFC powder decreased, the water solubility index increased, and the water absorption index and swelling power decreased. In addition, compared with the fruiting body of G. lucidum, the contents of G. lucidum triterpenes and ganoderic acid in the FFC were significantly increased (P<0.05), which were 1.68  and 2.07 times of those of G. lucidum fruiting body, respectively. The GFC obtained by G. lucidum solid-state fermentation of corn had more balanced nutritional structure, improved functional activity and higher nutritional value. Compared with corn, the macromolecular substances structure of GFC was changed, the processing characteristics were improved, as well as the blending characteristics. The results provided reference and guidance for the study of improving grain characteristics by edible fungi fermentation.
    • Analysis on Quality Character of Five Flaxseed Varieties in Different Altitude Regions of Zhangye
    • MIU Chunqing1, LIU Qin1, FAN Huiling2, WANG Juan1, BAI Shengwen3, HE Shuping1, BAI Jing1, WU Zixiao1*
    • 2021, 11(3):  330-337.  DOI: 10.19586/j.2095-2341.2020.0131
    • Abstract ( ) PDF (1143KB)( )
      • Flaxseed is one of the main cash crops in Gansu Province, and Hexi area below 2 400 m above sea level is a high-yielding area in Gansu Province. In order to find out the influence of different altitudes on the quality characteristics of flax and the best planting area of different flax varieties in Zhangye, the content differences of the conventional quality indexes, saturated fatty acids and unsaturated fatty acids of 5 flax varieties in 4 different altitudes in Zhangye City were analyzed by using near infrared quality analyzer. The results showed that, the interaction effect between varieties and altitudes with the contents of protein, crude fat, dietary fiber, palmitic acid, heptadecanoic acid, myristic acid, tetracarboxylic acid, oleic acid and α-linolenic acid was extremely significant (P<0.01). The content of behenic acid, palmitoleic acid, cis-11-eicosapentaenoic acid, linoleic acid, γ-linolenic acid and cis-11,14,17-eicosatrienoic acid changed little with altitude and had good stability. On the basis of breeding goal of high oil content, taking into account other quality breeding goals such as high three unsaturated fatty acids (α-linolenic acid, oleic acid and linoleic acid), low two saturated fatty acids (palmitic acid and stearic acid) and high protein, the most suitable flax varieties to be planted in Ganzhou District of Zhangye City, Landao Town of Gaotai County and Sanbao Town of Minle County, and Liuba Town of Minle County were 5-9812-2-1, 09-3-11, Zhangya 2, respectively. Different altitudes had an important influence on the quality indexes of flax. As a production base of high-quality flax seeds, Zhangye City can make use of the different suitable planting areas of different flax varieties to vigorously develop quality breeding and comprehensive development of flax seeds.
    • Bioinformatics Analysis of the Structure and Function of the Protein Encoded by ELO Gene in Acanthopagrus schlegelii
    • XU Guangping, ZHANG Zhiyong, REN Zhonghong, ZHANG Zhiwei*
    • 2021, 11(3):  344-352.  DOI: 10.19586/j.2095-2341.2020.0143
    • Abstract ( ) PDF (7604KB)( )
      • Black porgy (Acanthopagrus schlegelii) is a marine economic fish with strong resistance to stress. However, it is impossible to overwinter outdoors in the north of Yangtze River, and it is time-consuming and labor-intensive to overwinter indoors every year. The structure and function of  the protein encoded by fatty acid elongase (ELO) gene of A. schlegelii were studied in order to cultivate the strain of A. schlegelii with low temperature tolerance and explore its molecular mechanism. Firstly, the ELO amino acids of five kinds of fish, such as A. schlegelii, Sparus aurata, Siniperca chuatsi, Epinephelus coioides, Cyprinus carpio, were sequenced by DNAman 8 software, and their homology and evolutionary relationship were analyzed. Then, the physicochemical properties, subcellular localization, signal peptide, transmembrane region, splicing site, protein phosphorylation, glycosylation, secondary structure, domain, molecular function and protein interaction of ELO protein of A. schlegelii were analyzed by bioinformatics tools, and homologous modeling and three-dimensional structure prediction were carried out. The results of amino acid sequence alignment showed that the sequence homology between A. schlegelii and other fishes was high. Among the five fishes analyzed, A. schlegelii had the closest genetic relationship with Sparus aurata and the farthest genetic relationship with Cyprinidae fishes. Bioinformatics analysis showed that ELO protein was a basic, small molecule, stable and non-secretory hydrophilic protein, and subcellular localization was in cytoplasm, nucleus and mitochondria. There were 22 splicing sites, 19 phosphorylation sites and 9 lysine saccharification sites in the protein, but there were no glycosylation sites and signal peptides. It contained a variety of secondary structures, among which α-helix was the main one, with one domain and seven transmembrane regions; ELO protein may have direct interaction with other 10 protein, which may affect estrogen synthesis. Through bioinformatics analysis of the structure and function of the protein encoded by ELO gene of A. schlegelii, it was preliminarily determined that it was related to low temperature tolerance. The research results provided a basic theoretical basis for breeding low-temperature resistant strains of A. schlegelii.
    • Effects of Long-term Drinking of Hydrogen-rich Water on the Physiological Function of Normal Rats
    • HE Jin1§, XUN Zhiming2§, XIE Fei1*, YI Yang1, LIU Mengyu1, ZHAO Pengxiang 1
    • 2021, 11(3):  353-360.  DOI: 10.19586/j.2095-2341.2021.0026
    • Abstract ( ) PDF (1565KB)( )
      • A large number of animal experiments and clinical trials have shown the potential positive effects of hydrogen on the prevention or treatment of diseases. Although the safety of hydrogen has been widely recognized at present, there are still a lack of experimental data supporting whether long-term hydrogen intervention affects the physiological function of the body. In order to explore the effects of long-term drinking of hydrogen-rich water (HRW) on the physiological function, we elaborated the body and organ weight of rats, the changes of water, food intake, feces and urine excretions, and the cardiac function. Besides, the blood indicators were also monitored. The results were as follows: HRW had no significant effects on the blood routine indicators, fasting blood glucose and the liver function index. The serum triglyceride level of rats in HRW group was significantly elevated (P＜0.05), but there were no significant differences in cholesterol, total bile acid and uric acid between two groups. HRW had no significant effects on the cardiac function of rats. The brain weight of rats increased markedly in HRW group in comparison with the control group (P＜0.05); HRW had no significant effects on body and other organs weight, water and food intake as well as faeces and urine excretions. We observed the long-term effects of HRW intervention, which is of basic research value and clinical significance.
    • Stabilized CD115 by Optimizing Sample Processing and Accurate Analysis of Murine Monocyte and its Subsets
    • LIU Yining, SONG Junzhe, JIANG Xiao, CHEN Chao, ZHOU Yuan, XING Wen*
    • 2021, 11(3):  361-368.  DOI: 10.19586/j.2095-2341.2021.0028
    • Abstract ( ) PDF (8746KB)( )
      • As the essential part of defense system, the changes of monocytes may reflect the inflammation and other disease states to some extent. Using flow cytometry to detect the surface antigens of monocyte could analize  the proportion changes of monocytes and reveal the role of monocytes in the occurrence and development of diseases. In view of the poor stability of mouse monocyte specific antigen CD115, in the process of flow detection, the influencing factors were optimized to ensure the accuracy of detection results. First, the impact of temperature and time on the analysis of CD115  was measured before or after CD115 antigen-antibody binding. Next, the effect of fixative paraformaldehyde (PFA) on the CD115 stability was also examined. In addition, mouse monocytes were analyzed by negative gating with several lineage antibodies (Lin) including CD11c, CD49b, Ly6G, Ter119, CD3e and B220, followed by positive gating with CD11b and CD115 antibodies, and finally divided into monocyte subsets by the expression level of Ly6C. The results showed that temperature and storage time had significant effects on the stability of CD115. The percentage of CD11b+CD115+ cells stayed constant when incubated on ice for up to 6 h. However, the detectable CD11b+CD115+ cells decreased significantly if the sample were left at room temperature for 1 h and even vanished after 0.5 h if the temperature increased to 37 ℃. After fixed by PFA, the percentage of CD11b+CD115+ cells maintain the same for at least 3 d when stored at 4 ℃ in the dark. Based on this optimized method, using the combined antibody could better analyze mouse monocytes and their subsets, which might detect the population more accurately, and made it possible for further investigating the biological characteristics of monocytes and their effects in disease.
    • Research on the Role of IL-13 Inhibitors in Tail Disc Degeneration in Rats After Injury
    • TAO Hongpin1, ZHANG Mi2*, YOU Changjiang1, GE Hui1, LIU Yang2, ZHENG Xiannian1
    • 2021, 11(3):  369-377.  DOI: 10.19586/j.2095-2341.2021.0038
    • Abstract ( ) PDF (8123KB)( )
      • To explore the effect of interleukin-13 signaling pathway on intervertebral disc degeneration in rats, we established a rat model of degeneration of the tail intervertebral disc. The experiment was divided into blank, control, low-dose, middle-dose, and high-dose intervention groups. The morphological changes of intervertebral discs by HE staining and Masson staining was observed and scored. Quantitative analysis of glycosaminoglycan, chondroitin sulfate, keratan sulfate, and hyaluronic acid content changes was analyzed in intervertebral discs by DMMB method. mRNA expression levels of typeⅠ and typeⅡ collagen was analyzed by RT-PCR analysis. TypeⅠand typeⅡ collagen content was analyzed by western blot analysis. HE and Masson staining results showed that the pathological changes of the intervertebral disc were reduced compared with the control group, the fibrous annulus arrangement was more regular, the rupture site was reduced, the number of NP cells was increased, and the collagen fibers were reduced. sIL-13Rα2-Fc intervention increased GAG and HA content, Ⅰ collagen and the CS/KS ratio, and decreased Ⅱ collagen content. These results indicated that sIL-13Rα2-Fc can effectively reduce the degeneration of the intervertebral disc, and it is positively correlated with the action time and concentration.
    • The Biological Characteristics and Transcriptome Changes of Platelets in the Mouse Peritonitis Model
    • SUN Zhiqiang, XIA Meijuan, ZHENG Lin, ZHAO Jingjing, SU Pei, WANG Hongtao, ZHOU Jiaxi, LIU Cuicui*
    • 2021, 11(3):  378-385.  DOI: 10.19586/j.2095-2341.2021.0021
    • Abstract ( ) PDF (6132KB)( )
      • As the smallest non-nucleated blood cell, platelets play  important roles in regulating innate and adaptive immunity beyond the classic hemostatic function. However, the molecular mechanism of platelets in immune regulation remains relatively understudied. The mouse peritonitis model was constructed by injecting heat-inactivated Escherichia coli (E. coli) into the abdominal cavity. The dynamics of peritoneal immune cells and peripheral blood cells during acute inflammations were also detected by using blood routine, flow cytometry and other experimental methods. It was found that in the early stage of infection, neutrophils in the peripheral blood could quickly migrate to the abdominal cavity to participate in the inflammatory response, and the number and size of platelets were also changed significantly. The significant changes in the platelet transcriptome after infection were further revealed by RNA sequencing. Strikingly, the immune response-related genes, as well as the adhesion molecules in platelets were remarkably up-regulated. This study revealed the dramatic changes of platelet transcriptome under inflammatory conditions, providing a new perspective for understanding the underlying molecular mechanism of platelets in immune regulation.
    • The Semi-rational Designing of D-hydantoinase from Bacillus sp. AR9
    • FAN Shuai, LIU Kun, JIN Yuanyuan*, YANG Zhaoyong*
    • 2021, 11(3):  386-392.  DOI: 10.19586/j.2095-2341.2021.0049
    • Abstract ( ) PDF (4152KB)( )
      • D-4-hydroxyphenylglycine is a high-value chemical intermediate and has a wide range of applications in the pharmaceutical industries. The enzymatic method is the main way for the production of D-4-hydroxyphenylglycine, but the production of D-4-hydroxyphenylglycine is limited due to the lack of enzymes with high catalytic efficiency. In order to improve the catalytic efficiency of D-hydantoinase (HYD) from Bacillus sp. AR9 and the production of D-4-hydroxyphenylglycine, the analysis of substrate tunnel and site-directed saturation mutagenesis were performed. The activity of variants F159S, F159A and F65V were increased by 51%, 40% and 17% compared to the HYD, respectively. The enzyme kinetics of HYD and mutants illustrated that the Km of mutants (F65V, F159S and F65V/F159S) were similar for HYD. However, F65V, F159S and F65V/F159S showed the 1.3-, 1.9- and 2.0-fold increase in kcat compared with HYD. Specifically, enhanced catalytic efficiencies (kcat/Km) was achieved by the F65V/F159S, representing 2.4 times higher catalytic efficiency than that of HYD. The obtained high-catalytic efficiency mutants and the analysis of mutant kinetics were of important research significance and application value for the biotransformation of D-4-hydroxyphenylglycine.
    • Study on Synthesis of Uridine Diphosphate Glucuronic Acid Based on Double Enzyme Coupling Method
    • HE Lili, DOU Wenfang*, LYU Haichao, XUE Xinxin, ZHANG Wen, JIANG Nan
    • 2021, 11(3):  393-402.  DOI: 10.19586/j.2095-2341.2021.0007
    • Abstract ( ) PDF (2435KB)( )
      • Uridine diphosphate (UDP)-glucuronic acid is an important sugar donor in cells, which participates in many metabolic pathways and is also an important sugar donor for glycosylation in vitro. However, its high price and complicated process limit its large-scale use and cannot meet the production demand. Based on this, UDP-glucose was oxidized to UDP-glucuronic acid by double-enzyme coupling method, and the synthesis of reaction products was studied. With UDP-glucose as substrate and nicotinamide adenine dinucleotide (NAD+) as cofactor, UDP-glucuronic acid was synthesized by using UDP-glucose dehydrogenase (UGD) from Streptococcus pyogenes and lactate dehydrogenase (LDH) from pigs, and the products were detected by high performance liquid chromatography, mass spectrometry and nuclear magnetic resonance (1H NMR) to determine the structure and yield of the products. The results showed that UDP-glucuronic acid was the product of oxidation of UDP-glucose by double-enzyme coupling method. Under the action of UGD, UDP-glucose was oxidized to UDP-glucuronic acid, and the cofactor NAD+ was recycled under the action of LDH, which reduced the feedback inhibition of the high-energy product reduced nicotinamide adenine dinucleotide (NADH) on the reaction. The yield of the product was about 60.17%. The research increased the production of UDP-glucuronic acid, which provided a new idea for the subsequent industrial preparation.

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