Table of Content

18 April 2020, Volume 37 Issue 2 Previous Issue    Next Issue

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Construction of a multiplexing gene modulation system in breast cancer cells MEI Yi, WANG Zhen, DAI Xiao-feng 2020, 37 (2):  1.  doi: 10.3969/j.issn.2095-1736.2020.02.001 Abstract ( 409 )   PDF   Save With the CRISPR gene editing technology widely implemented in both plants and animals, a multi-gene editing system in breast cancer was constructed by harnessing the self-shearing characteristics of endogenous tRNA, integrating tRNA and multiple single guided RNA (sgRNA) targeting genes of interest into a single plasmid. Four transcription factors KLF4, MYC, SOX2 and OCT4 were modulated simultaneously using our system in breast cancer cell line MCF7 where the function and reliability of our system was verified from the transcriptional expression, protein expression and functional changes assays. The expressions of all modulated genes were upregulated above 2-fold, with the modulated cell displayed higher migration and invasive abilities and an increased cell availability by 50%. The proportion of stem cells was also increased from 2.57% to 18.5%. Concomitant multiplexing modulation of the same gene panel using our constructed system in breast cancer cell line SUM149PT was also achieved. Thus, based on CRSIPR, a standard, accurate, reproducible and efficient multiplexing gene modulation system in breast cancer cells was successfully built. Related Articles | Metrics

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Expression and optimization of recombinant human gastric factors in Corynebacterium glutamicum DONG Gui-bin, PAN Ying-yue, SI Ya-nan, WANG Xin-yue, BAI Zhong-hu, LIU Xiu-xia, YANG Yan-kun 2020, 37 (2):  5.  doi: 10.3969/j.issn.2095-1736.2020.02.005 Abstract ( 378 )   PDF   Save The human gastric factor(GIF) is a very important protein, and it plays a very important role in assisting the absorption of VB12 through small intestinal wall cells. If there be synthetic disorder of the protein, it will lead to the occurrence of atypical anemia in the body and reduce immunity. C. glutamicum is a food-grade safe microorganism, no endotoxin is detected in the fermentation broth of C. glutamicum. In addition, it has some unique advantages in its use for protein expression. In order to express pharmaceutical GIF in C. glutamicum, a recombinant gene rgif was synthesized, and codon optimization of the gene sequences to ensure normal translation of rgif into GIF. The recombinant gene rgif was successfully cloned into the expression vector pXMJ19, the vector containing rgif was introduced into C. glutamicum, and the protein GIF was expressed successfully. To improve the yield of GIF, fermentation process was optimized through orthogonal experimental design. The optimal fermentation conditions to express GIF in C. glutamicum were as follows: IPTG concentration was 100 μmol/L, time of adding induction was 10 h, fermentation time was 22 h and fermentation temperature was 23 ℃. Under which, GIF was abundantly expressed in C. glutamicum, and it was soluble. Proteins harvested could be purified by HisTrap FF column. The protein could also be detected by an ELISA kit, and the yield of GIF reached to 42.3 mg/L. According to the results of orthogonal experiments, it was found that the yield of GIF continued to decrease as the fermentation temperature increased from 23 ℃ to 37 ℃. The yield of GIF was also continuously reduced during the time of adding induction from 0 to 10 h. When it comes to the fermentation time, GIF production increased continuously from 18 to 22 h, but decreased gradually after 22 h. As to IPTG, GIF production gradually increased as its concentration increased from 50 to 100 μmol/L, but decreased thereafter. The effect of the above four factors on protein production was weakened in turn. It could be seen that giving a lower temperature, delaying the time of induction would be an effective work to improve the soluble expression of GIF. This was the first report of the expression of GIF by prokaryote, which would provide a viable solution for prokaryotic expression of GIF. Related Articles | Metrics

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Stability of episomal plasmids containing ARS/CEN  elements in Pichia pastoris LIU Guo-qiang, SUN Wen-hao, ZHANG Qing-ye, ZHOU Jin-kai, BAI Zhong-hu, LIU Xiu-xia, YANG Yan-kun 2020, 37 (2):  10.  doi: 10.3969/j.issn.2095-1736.2020.02.010 Abstract ( 929 )   PDF   Save Pichia pastoris (P. pastoris) is one of the most widely used heterologous protein expression systems. The most widely used heterologous protein expression strategy is the integrated plasmids; the episomal plasmids are greatly limited in Pichia pastoris due to their high instability. In this research, ARS/CEN and other components were ligated into pPIC9K vector to construct autonomously replicating episomal plasmid pPIC9K-ARS/CEN. The way of subculturing to detect plasmid loss was used to investigate the stability of episomal plasmid in Pichia pastoris during cell subculture. In the absence of selective pressure, the episomal plasmid containing the ARS/CEN element had extremely high stability before cell culture for ten generations, and then the episomal plasmid began to be lost, and the loss rate to the 20th generation plasmid was as high as 92.94%. The results of this study provided not only a good support for the construction of a stable episomal plasmid Pichia pastoris expression system, but also a practical plasmid elimination method. Related Articles | Metrics

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The promoter methylation of microRNA-193b and microRNA-141 gene in septic shock mice WU Si-si, LI Xue, LI Ru-li, JIANG Wei, WANG Xiang-xiu, WANG Xiao-xiao 2020, 37 (2):  14.  doi: 10.3969/j.issn.2095-1736.2020.02.014 Abstract ( 250 )   PDF   Save To investigate the hypermethylation status of microRNA-193b and microRNA-141 in septic shock mice, with the use of a mouse septic model induced by cecal ligation and puncture, the cardiac function was further detected with a multi-channel physiological signal acquisition system. The methylation statuses of both microRNA-193b and microRNA-141 in heart, liver, lung and small intestine tissues were detected by using bisulfite sequencing PCR and a real-time PCR method, respectively. The results indicated that the cardiac function was significantly impaired in the mice with late stage of sepsis shock. The methylation rate of microRNA-193b in heart tissue of the septic mice was 23.9%, 1.9% higher than that in normal tissue（P<0.05）. The methylation rates of microRNA-141 in lung and intestine tissue of the septic mice were 31.2% and 36.9%, 3.4% and 4.6% higher than those in normal tissue（P<0.01）, respectively. CpG islands in microRNA-193b and microRNA-141 gene promoter region were hypermethylated, which might be the reason for the changes in the expression of microRNA-193b and microRNA-141, suggesting that both of them might participate in the regulation on the pathophysiological state by regulating the protein expression of their downstream inflammation-related factors. Both microRNA-193b and microRNA-141 might be new biomarkers and targets for the infectious diseases diagnose and therapy. Related Articles | Metrics

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Expression and bioinformatics analysis of FCA gene in Dendrobium officinale Kimura et Migo LI Liang-jian, HU Rui, PEI Wei, WANG Wan-jun 2020, 37 (2):  18.  doi: 10.3969/j.issn.2095-1736.2020.02.018 Abstract ( 204 )   PDF   Save The FCA (FLOWERING CONTROL LOCAL A) gene is a conserved gene that promotes plant flowering in the autonomous pathway. The full-length cDNA sequence of FCA gene was cloned from Dendrobium officinale Kimura et Migo by siloco PCR and rapid amplification of cDNA ends technology (RACE), and named as DoFCA. Bioinformatics analysis revealed that the open reading frame of the DoFCA gene was 2301 bp, containing 19 exons and 18 introns. The DoFCA encoded a protein with 766 amino acid residues which had two RRM domains at N-terminal (131-210, 220-298) and one WW domain at C-terminal (605-634). Promoter analysis revealed that there were regulatory elements in the promoter region of this gene, which were closely related to meristem-specific activation, endosperm expression and expression regulation of anther-specific genes. Protein sequence homology analysis showed that the conserved region mainly concentrated in both the RRM and WW domain, which indicated that the protein was functionally conserved in different species. Phylogenetic analysis showed that DoFCA protein had the closest evolutionary relationship with Dendrobium-like FCA protein, and it was found that FCA protein differentiated during the evolution of monocotyledons and dicotyledons. Analysis of the DoFCA-WW/FY-PPLPP complex revealed that the four sites (14Tyr, 16Tyr, 23Ser, and 25Trp) in the WW domain interacted most closely with FY-PPLPP motif, and the 23Ser residue formed a hydrogen bond with the second Pro of FY-PPLPP motifs. The results of RT-qPCR analysis showed that the expression level of DoFCA was higher in flower, followed by stem and leaf, and the lowest in root. Under low-temperature stress, the expression level decreased rapidly after treated for 12 h, then increased gradually, and finally maintained at a high level. These results suggested that the gene might play an important role in the flower development and formation of Dendrobium officinale Kimura et Migo and also in the process of low temperature induced flowering. Related Articles | Metrics

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Catalytic mechanism analysis of glycoside hydrolase GH97 family member PspAG97A ZHANG Xiao-min, CHEN Fei-yun, ZHANG Xue-cheng, HE Chao, XIAO Ya-zhong 2020, 37 (2):  24.  doi: 10.3969/j.issn.2095-1736.2020.02.024 Abstract ( 233 )   PDF   Save The glycoside hydrolase GH97 family is a unique family that contains both inverting and retaining members. It is unclear how the two catalytic mechanisms differentiate. The catalytic mechanism of PspAG97A, a member of GH97 family, was analyzed. It was proved that PspAG97A performs the inverting catalytic mechanism according to the ratio change of α-glucose and β-glucose produced by the enzyme at different reaction time detected through high performance liquid chromatography. We tried to change the inverting catalytic mechanism of PspAG97A to retaining by structural analysis and site-directed mutagenesis. The active site of PspAG97A was superimposed with that of BtGH97b belonging to the GH97 retaining subfamily, and the related sites G407, E377, E456 and chloride ion binding site R171 of PspAG97A were subjected to single point mutations and combined mutations to follow the catalytic device for the retaining type. The results showed that the activities of the mutants decreased significantly compared to the wild-type. We then analyzed the function of relevant residues. The above research not only deepens the understanding of the catalytic mechanism of PspAG97A, but also lays the foundation for the evolutionary relationship of two catalytic mechanisms within the GH97 family. Related Articles | Metrics

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Molecular evolution of SLC2A4 and its coding protein GLUT4 in aves LIU Gang, LI Qing-yue, WANG Cong, LIU Xiao-ying 2020, 37 (2):  29.  doi: 10.3969/j.issn.2095-1736.2020.02.029 Abstract ( 383 )   PDF   Save Birds need high-efficiency mechanism of blood glucose regulation to get energy for flying. SLC2A4 and its coding protein Glucose transporter type 4 (GLUT4) play a major role for glucose transport in skeletal muscle cells when birds fly. In this study, all of the 17 avian SLC2A4 sequences were got from GenBank, results showed that the sequences had high variation in the length and base composition. It also showed all the GLUT4 were hydrophilia and had many O-glycosylation sites, but had no transmembrane structure, and signal peptide sites were located in 11-57 site of GLUT4. Selection pressure analysis showed that it was positive selection in Carinatae, but negative selection in Ratitae. Using maximum likelihood (ML) and Bayesian inference (BI) methods based on the GLUT4, both of the trees were highly similar topologies and high bootstrap proportion values. The phylogenetic analysis showed that Struthioniformes, Apterygiformes and Tinamiformes formed together, then grouped with Galliformes, Anseriformes, Columbiformes and Passeriformes. Our results may provide useful information about the evolution of SLC2A4 in birds. Related Articles | Metrics

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The role of endogenous MHCⅠon the outgrowth of hippocampal neurons LYU Dan, ZHOU Duo-qi 2020, 37 (2):  33.  doi: 10.3969/j.issn.2095-1736.2020.02.033 Abstract ( 343 )   PDF   Save Accumulating evidence indicates that immune proteins major histocompatibility complex I (MHCⅠ) molecules are expressed by healthy neurons. Based on the study of related knockout animals, the neuronal MHCⅠ molecules have been proved to play important roles in synaptic formation, remodeling and plasticity, which are significantly different from their well-acknowledged immune functions. Using cultured hippocampal neurons, we show MHCⅠ proteins are expressed before neurite outgrowth. Knockout of MHC class I in cultured neurons or blocking of MHCⅠmolecules by MHCⅠ antibody increases the branch number of neurons. Blocking of pirB, which works with MHCⅠin immune system, mimics the phenotype of increased dendritic branching. Our results imply that endogenous MHCⅠplays a role in limiting the neurite outgrowth during the development of hippocampal neurons. Related Articles | Metrics

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Analysis on the nucleosome distribution parameter model in eukaryotic model organisms FENG Ji-hua, GUO Ya-ru, MOU Jin, HUANG Yue-yue, LIU Ke, FAN Li-dong 2020, 37 (2):  37.  doi: 10.3969/j.issn.2095-1736.2020.02.037 Abstract ( 314 )   PDF   Save The spatial distribution of eukaryotic nucleosomes affects the transmission of genetic information and is the basis of epigenetic and genetic engineering. Mathematical modeling is the basic way to study the three-dimensional structure and gene regulation of DNA, but the spatial dimension modeling is a problem for scientific research. To compare the distribution of nucleosomes around the transcription start site of single-cell and multi-cell biological genes, we used high-resolution yeast and Drosophila nucleosome localization experimental data to construct a nucleosome distribution model. In the model construction, the fitting effects of polynomial, Fourier series, Gaussian function and sine function were comprehensively compared, and the sinusoidal complex function was finally determined as the nucleosome distribution model of yeast and Drosophila. On this basis, the scale and frequency domain analysis of the periodic characteristics and evolutionary imprints of yeast and Drosophila nucleosome distribution showed that there were significant differences in the tissue structure between yeast and Drosophila chromosomes. The research ideas in this paper have an important reference value for using mathematical modeling and signal processing methods to obtain genomic structure information. Related Articles | Metrics

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Effects of sodium houttuyfonate in combination with erythromycin on lrgB of Staphylococus epidermidis GUAN Yan, XU Gan-fei 2020, 37 (2):  41.  doi: 10.3969/j.issn.2095-1736.2020.02.041 Abstract ( 236 )   PDF   Save Apoptosis occupied the dominant status of the programmed cell death (PCD), which is often considered to be unique to eukaryotes. Bacterial Cid/Lrg systems similar to eukaryotic apoptosis have also been concerned. Staphylococcus epidermidis is one of the most important pathogens causing nosocomial infections; and the pathogenesis of S. epidermidis is closely related to the formation of biofilms on the surface of artificial devices (joints, contact lenses, heart valves, indwelling catheters, etc.) implant in the human body. To evaluate the effects of sodium houttuyfonate and its combination with erythromycin on the dissolution and biofilm formation of S. epidermidis, the MIC of sodium houttuyfonate, erythromycin and vancomycin against S. epidermidis was determined by serial dilution method. Fluorescence quantitative PCR was used to determine the transcription level of lrgB（Gene B regulated by lytSR） in different time periods after the action of sodium houttuyfonate and its combination with erythromycin, erythromycin and vancomycin on S. epidermidis. The effect of sodium houttuyfonate and erythromycin on the morphology of S. epidermidis biofilm was observed under a microscope. It was found that the combination of sodium houttuyfonate and erythromycin significantly increased the expression of lrgB at the beginning of the treatment (P<0.05). The sub-inhibitory concentration of sodium houttuyfonate combined with erythromycin also significantly down-regulated the expression of lrgB at 6 h, 12 h, 24 h and 48 h (P<0.05). Morphological observation also confirmed the destructive effect of the sub-inhibitory concentration of sodium houttuyfonate combined with erythromycin on the biofilm of S. epidermidis. The experimental results confirmed that the combination of sodium houttuyfonate and erythromycin could regulate the expression of lrgB at a specific concentration, thus inhibiting and destroying the formation of S. epidermidis biofilm and promoting the dissolution and death of bacteria. Related Articles | Metrics

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High-throughput analysis of bacterial diversity in highland barley cultivation soil in Lhasa LIU Qing-hai, PAN Hu, Dawazhuoma, TIAN Yun, LIU Hu-hu, WANG Chong, LU Xiang-yang , BAI Jun-ping 2020, 37 (2):  46.  doi: 10.3969/j.issn.2095-1736.2020.02.046 Abstract ( 186 )   PDF   Save In order to understand the bacterial community structure in the farmland soil of highland barley planting in Lhasa, and to clarify the influence of different growing periods and different locations of highland barley on the bacterial diversity, the community structure and diversity of bacteria in highland barley cultivation soil were analyzed by high-throughput sequencing technology with the highland barley cultivation soil as the experimental material. Result showed that 37 265-40 008 effective sequences and 4094-4730 OTU were obtained from each sample of highland barley soil microbial sequencing in this study. According to the rarefaction curve and sequencing depth index, the result of the sequencing was more comprehensive covering the soil microorganism community. Shannon index and OTU number of each sample in different periods showed Group 1 (March 25, sowing early)  Related Articles | Metrics

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Distribution of fecal indicator bacteria and indigenous pathogenic vibrio in the seawater of Dalian typical bathing beach MING Hong-xia, ZHANG Ying-xue, JIN Yuan, SU Jie, SHI Yan, FAN Jing-feng 2020, 37 (2):  52.  doi: 10.3969/j.issn.2095-1736.2020.02.052 Abstract ( 259 )   PDF   Save Fecal indicator bacteria may not reflect the pollution of marine indigenous pathogenic bacteria. Therefore, the distribution of bacteriological indicators, including enterococcus, Vibrio parahaemolyticus, V. vulnificus and V. cholerae was analyzed during the peak swimming season in Dalian Fujiazhuang and Xinghai bathing beachs. The results showed that the exceeding standard rate of enterococcus was 58.2% (n=134), and the detection rates of virulence gene markers of V. parahaemolyticus, V. vulnificus and V. cholerae were 24.6%, 10.4% and 4.5% (n=134), respectively. These two bathing beaches were not only polluted by fecal pathogens, but also existed the pathogenic V. parahaemolyticus and V. vulnificus, besides, the pathogenic V. cholerae was also detected in Fujiazhuang bathing beach, which all pose potential risks to human health. The speed of wind, wave height and rainfall had great impacts on the distribution of enterococcus. Water temperature, air temperature, salinity and transparency were the main factors affecting the distribution of pathogenic V. vulnificus. pH and wave height had great influences on the distribution of V. parahaemolyticus. Due to the different ecological characteristics of enterococcus and Vibrio spp., we suggested that important pathogenic vibrio should be considered into the current routine monitoring of bathing beach. Related Articles | Metrics

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Spectroscopic measurements of the electric potential difference (ΔΨ) of C3 leaves LYU Hui, WANG Chun-bo, WANG Fen, CUI Bao-lu, SONG Li-sha 2020, 37 (2):  57.  doi: 10.3969/j.issn.2095-1736.2020.02.057 Abstract ( 273 )   PDF   Save C3 photosynthesis is one of the most important photosynthetic mechanisms, in which light-driven electron transport is coupled to the movement of protons from the chloroplast stroma into the thylakoid lumen. With it, positive-charged protons accumulate in the lumen, and the protons decrease in the stroma, producing the transmembrane proton motive force (pmf), eventually, driving the conformational variation of the transmembrane thylakoid ATPase which converts ADP (adenosine diphosphate) and Pi (inorganic phosphate) into ATP (adenosine triphosphate) which are subsequently used in the ensuing Calvin cycle to make the organic products. Proton motive force contains two components, one is the chemical potential difference caused by the transmembrane osmotic pressure, and another pmf component, i.e. ΔΨ, is an essential indicator of light energy transduction, which triggers a so-called electrochromic shift of the absorption maximum of the pigment(s) to 515 nm. Majorly, carotenoid pigment and chlorophyll b pigment are responsible for the electrochromic shift. This shift is not solely intensified by ΔΨ, also overlapped by the absorption change caused from the “light scattering” effect. The interpretation of this signal is complicated, which indeed find the P515 measurement a hard trial for the example of ΔΨ probing, particularly in the long-term temporal range. It has seldom been reported in the published papers domestically for the P515 measurement. In this work, tobacco leaves (Nicotiana tabacum) were measured by Dual-PAM-100 chlorophyll fluorescence photosynthesis analyzer using the novel P515/535 Emitter-Detector module. The results illustrated the P515 curves when single turnover flash was on, when actinic light was lasting for 1 s, and when actinic light was lasting for 1 min followed by another 2 min dark phase interval. Our results could offer a technological foundation for the scientific research of the photosynthetic primary energy transduction. Related Articles | Metrics

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Morphological structure observation and photosynthetic characteristics analysis of taro leaf SHENG Jie-yue, CUI Wen-xue, ZHANG Er-jin, YU Xu-run, XIONG Fei 2020, 37 (2):  61.  doi: 10.3969/j.issn.2095-1736.2020.02.061 Abstract ( 334 )   PDF   Save Taro (Colocasia esculenta) is a perennial bulbous plant of Araceae family. The leaf and petiole of taro have strong photosynthetic capacity and the structure and photosynthetic characteristics of leaves from different taro varieties are different. Two types of taro varieties ( Binglang′ and Xianghe′) that significantly differed in yield and architecture, were used as experimental materials in this study. By using resin semi-thin section, microstructural and ultrastructural observation and other experimental methods, the morphological and photosynthetic characteristics of taro leaf were systematically observed and analyzed. The photosynthetic rate, transpiration rate, intercellular CO2 concentration and stomatal conductance of the leaves of Xianghe′ were higher than those of the Binglang′. Compared with the Binglang′, Xianghe′ was larger in air cavity, denser in the number of pant stomata, and thicker in the palisade tissue. The surface of the Binglang′ leaves was rough and the stomas were small. The surface of the Xianghe′ leaves was smooth and the stomas were large. The above results showed that there were significant differences in morphological structure, photosynthetic characteristics between Xianghe′ and Binglang′. Binglang′ has more developed conducting tissue and Xianghe′ has smaller and denser air cavity, higher stomatal conductance, more rapidly transpiration rate and faster photosynthetic rate. The results could provide some information for the investigation of organ development and photosynthetic mechanism of taro. Related Articles | Metrics

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Investigation and study on the current situation of Tibetan medicine plant resources in Banma County, Qinghai Province #br# KANG Jun-hua, Longzhuduojie, SU Xu, ZHANG Jie, Laben 2020, 37 (2):  65.  doi: 10.3969/j.issn.2095-1736.2020.02.065 Abstract ( 312 )   PDF   Save Tibetan medicinal plant resources are abundant in Banma County of Qinghai Province and have a long history of the utilization of folk traditions. It is of great significance to further explore and develop the knowledge of Tibetan traditional folk medicine culture in Banma County. In this paper, the traditional Tibetan medicinal plants in eight townships and one town of Banma County were classified and counted by means of field investigation, collection of specimens and data consulting. It was found that medicinal plants could be divided into four categories: fungi, ferns, gymnosperms and angiosperms, with 478 species belonging to 228 genera and 70 families. Among them, there were 463 angiosperms belong to 64 families, and the most species was Compositae, with 62 species, which accounted for 12.97% of the total species. The medicinal parts of gymnosperms included resins, cones, trunk endothelium, needles, etc., which could be used to treat wind-cold and dampness arthralgia, furuncle and ulcer, parasitosis, chronic bronchitis, hernia and other diseases. The study was helpful for further promoting the development of traditional Tibetan medicine culture in Banma County. At the same time, it also provided a reference for the protection and sustainable development of medicinal plant resources in the region. Related Articles | Metrics

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Nest and nest-site characteristics of the white-rumped munia Lonchura Striata in urban green land PAN Yang, GAO Ji-xi, AN Shu-qing, ZHOU Ke-xin, YUAN Bao-dong 2020, 37 (2):  68.  doi: 10.3969/j.issn.2095-1736.2020.02.068 Abstract ( 351 )   PDF   Save Urban green land is a kind of habitat shelter which relates to bird safety, and birds can show obvious preference in habitat selection. With the acceleration of urbanization, how to adapt to the disturbance of urban environment and reproduce successfully is a vital problem faced by urban birds, and the nest site selection of birds in breeding period reflects bird life history strategies and urban adaptability of urban birds. In order to explore the adaptability of urban birds, nest and nest-site characteristics, we collected 5 parameters of white-rumped munia’s (Lonchura striata) nest and also 19 ecological factors of 39 nests from March to May, 2017 in Yizhou City of Guangxi Province. The results showed as follows: the nest parameters were characterized in that—the outer diameter was(123.95±15.25)mm， while the inner diameter was(102.01±9.51)mm, the nest deep was(84.8±9.07)mm and the nest height was (115.66±9.37)mm, and the nest height to the ground was (3.64±1.17)m. The principal components analysis showed that there were 6 most important factors which affect the nest characteristics of white-rumped munia in spring and the accumulative ratio of contribution achieved was 83.607%. Safety factor（i.e. height of tree, tree coverage and canopy), played the most important role in habitat selection and the second to the forth factors were food factor(i.e. distance to human settlement and road and forest edge), interference factor(i.e. shrub coverage and height, herb coverage), and water factor(i.e. distance to water), and the last factor was geography factor(i.e. altitude and slope). In order to avoid the influence of human disturbance, white-rumped munia tend to locate its nest in the place with high hidden that next to the top of tree, and it shows the adaptability to urban habitats during breeding period. Related Articles | Metrics

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The effects of magnetic fields on tumor metastasis FENG Shuang, LI Jun, JI Xin-miao, HU Li-jiang, ZHANG Xin 2020, 37 (2):  72.  doi: 10.3969/j.issn.2095-1736.2020.02.072 Abstract ( 352 )   PDF   Save There are a number of cellular and animal studies about static magnetic fields and low-frequency rotating magnetic fields based on permanent magnets have shown inhibitory effects on tumor growth. However, tumor metastasis is one of the major reasons for cancer patient lethality, which is a hotspot for medical research. Currently, there are some studies showing that magnetic fields themselves can affect the invasion and migration of tumor cells, as well as cancer metastasis. People have also taken advantage of nanotechnology by combining magnetic fields with different parameters and nanomaterials for tumor targeting and thermomagnetic effects, which have shown great progression in tumor metastasis inhibition and tumor cell enrichment. This review summarized, analyzed and compared the relevant data on the invasion and migration of tumor cells, the metastasis of tumor cells in static magnetic field and the dynamic magnetic field, as well as the magnetic field combined with nanomaterials, including magnetic field parameters and treatment, cell type and the resulting intracellular changes. This helped people not only understand the effects of the magnetic field exposed in daily life on the organism, but also optimize the magnetic field parameters in the future, so that the magnetic fields can be applied to tumor-assisted treatment. Related Articles | Metrics

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Advances in microbiological degradation of 2-hydroxypyridine LU Peng, LIU Ai-min 2020, 37 (2):  78.  doi: 10.3969/j.issn.2095-1736.2020.02.078 Abstract ( 303 )   PDF   Save Pyridine is a class of N-heterocyclic organic pollutants which has high biological toxicity and long existed in the environment. 2-Hydroxypyridine is an important pyridine derivative and intermediate metabolite in the biodegradation of N-heterocyclic organic compounds such as pyridine and nicotine. It is more water soluble, more mobile, and more leachable into groundwater, soil, which causes widespread contamination in environment and threatens ecological environment and human health. Microbial degradation with the characteristics of high efficiency, low cost, no secondary pollution is an effective measure to remove the environment pollution of 2-hydroxypyridine, which has a good application prospect. After years of research, a number of strains with capacity to degrade 2-hydroxypyridine have been isolated and some degradation mechanisms have been clarified. In this paper, we summarized the latest research progress on the biodegradation of 2-hydroxypyridine from the aspects of microorganism resource, degradation pathway, key enzymes and genes, and then discussed about the current development trend and propose suggestions for its future research direction, to provide references for bioremediation of 2-hydroxypyridine-contaminated environments. Related Articles | Metrics

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Research progress of gasdermin protein family and pyroptosis SHI Ke-song, MA Chen-jie, MA Ling-ling, ZENG Jin 2020, 37 (2):  83.  doi: 10.3969/j.issn.2095-1736.2020.02.083 Abstract ( 981 )   PDF   Save AbstractAs a method of programmed cell death, pyroptosis has become a hot topic in recent years. It has attracted more attention in the research of infectious diseases, the occurrence and development of cancer, and some autoimmune diseases. The programmed death of cells, included pyroptosis, apoptosis, necrosis and autophagy, transformed and complemented each other, and established the complex death mechanism of cells. Pattern recognition receptors of cell can recognize the intracellular and extracellular pathogenic microbial components, and complete the assembly and activation of the inflammasome, then the pyroptosis signaling pathway is activated and cleavage of GSDMD by human or mouse caspase-1, human caspase-4, human caspase-5, and mouse caspase-11 liberates the N-terminal effector domain from the C-terminal inhibitory domain. The N-terminal domain oligomerizes in the cell membrane and forms a pore of 10-16 nm in diameter, through which substrates of a smaller diameter, such as interleukin-1β and interleukin-18, are secreted. Pyroptosis plays a key role in the response to extracellular infections and endogenous risk signals and thus plays an important role in the body′s natural immune response. In this paper, the characteristics of pyroptosis, the mechanism of induction and activation, the role of gasdermin, the role of formation and secretion of inflammatory factors were reviewedAbstractAs a method of programmed cell death, pyroptosis has become a hot topic in recent years. It has attracted more attention in the research of infectious diseases, the occurrence and development of cancer, and some autoimmune diseases. The programmed death of cells, included pyroptosis, apoptosis, necrosis and autophagy, transformed and complemented each other, and established the complex death mechanism of cells. Pattern recognition receptors of cell can recognize the intracellular and extracellular pathogenic microbial components, and complete the assembly and activation of the inflammasome, then the pyroptosis signaling pathway is activated and cleavage of GSDMD by human or mouse caspase-1, human caspase-4, human caspase-5, and mouse caspase-11 liberates the N-terminal effector domain from the C-terminal inhibitory domain. The N-terminal domain oligomerizes in the cell membrane and forms a pore of 10-16 nm in diameter, through which substrates of a smaller diameter, such as interleukin-1β and interleukin-18, are secreted. Pyroptosis plays a key role in the response to extracellular infections and endogenous risk signals and thus plays an important role in the body′s natural immune response. In this paper, the characteristics of pyroptosis, the mechanism of induction and activation, the role of gasdermin, the role of formation and secretion of inflammatory factors were reviewed. Related Articles | Metrics

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Advances on the high photosynthetic efficiency in plants XIAO Pu, LIU Hu-hu, WANG Chong, CHEN Yong-zhong, TIAN Yun 2020, 37 (2):  88.  doi: 10.3969/j.issn.2095-1736.2020.02.088 Abstract ( 866 )   PDF   Save It is of great significance to improve the crop planting benefit by improving the technical level of crop production. Photosynthesis is the basis of plant growth and development. It will play an important role in improving the production level of plants, by cultivating the plant varieties with efficient utilization of light energy. The high photosynthetic efficiency plants are the plants with high light efficiency. In the process of photosynthesis, green plants firstly capture solar energy through the light-harvesting antenna system on the leaves, and convert it into electrical energy at the complex center of the photosystems. Then, the electrons are further transferred to each protein complex and electron transporter of the photosynthetic membrane, and the energy is stored in ATP and NAD(P)H. Finally, the light energy is converted into chemical energy and stored as organic matter in plants. Focusing on how to improve the utilization efficiency of light energy in plants, we reviewed three important researches in this paper, including increasing the absorption of light energy, accelerating the transfer of electrons and energy transformation during photosynthesis, reducing the loss of light energy and improving the efficiency of carbon assimilation. Meanwhile, this paper pointed out the main shortcomings of the current research, including the single research of plants under the specific conditions, the lack of research on photosynthetic performance of plant population and the lack of research on the source-sink. On this basis, combining the recent research of the genome-wide association analysis, the emerging synthetic biotechnology and the phyllosphere microorganism, the future development was prospected, which will offer guidance to the research of the high photosynthetic efficiency in plants, and provide an important theoretical support for improving the crop yield in China. Related Articles | Metrics

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Ocular surface virus infection and prevention and treatment in new coronavirus pneumonia epidemic XU Zi-ming, ZHANG Qing, TAO Li-ming 2020, 37 (2):  92.  doi: 10.3969/j.issn.2095-1736.2020.02.092 Abstract ( 309 )   PDF   Save The epidemic of the novel coronavirus pneumonia broke out has drawn great attention from all walks of life. With the spread of the epidemic, which has brought huge challenges to public health prevention and control and clinical diagnosis and treatment systems at home and abroad. The new coronavirus (SARS-CoV-2) is a type of coronavirus (short as CoV). Since the isolation of human coronavirus in 1965, a total of seven coronaviruses have been found to cause human disease. There is evidence that conjunctiva is one of the entrances to SARS-CoV-2 infection, suggesting that SARS-CoV-2 may be transmitted through the ocular surface, but clinical data and laboratory evidence on ocular infection with SARS-CoV-2 are currently lacking. We pay attention to novel coronavirus pneumonia, and retrospectively analyze related research on ocular diseases caused by viral infections, to better prevent and treat ocular viral infections, help to protect eyes during the epidemic, standardize ophthalmic diagnosis and treatment system, and propose scientific prevention and control measures. Related Articles | Metrics

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Establishment of a method for efficient preparation of recombinant human α-synuclein fibrils LUO Hai-yu, WU Zheng-cun, MA Kai-li 2020, 37 (2):  96.  doi: 10.3969/j.issn.2095-1736.2020.02.096 Abstract ( 438 )   PDF   Save The DNA sequence of human α-synuclein was amplified from pcDNA3.1-α-syn vector by PCR, then cloned into PGEX-5X-1 vector, and a highly efficient prokaryotic expression vector of human α-synuclein was successfully constructed and named pGEX-5X-1-syn. The recombinant vector was transformed into BL21 strain and induced by IPTG. The recombinant human α-synuclein fibrils were obtained by optimized the inducing concentration, time and temperature of IPTG, purification method and fibril culture conditions. The preparation of fibrils was confirmed by thioflavin T staining and transmission electron microscopy. Results showed that after inducing by IPTG at a final concentration of 1.0 mmol/L for 3 h at 37 °C, human α-synuclein was expressed in large amounts. The GST fusion protein purification magnetic beads were used for protein purification, and the high-purity human α-synuclein could be obtained quickly and efficiently, and the purified yield reached 25 mg/L. Human α-synuclein fibrils were successfully prepared in large quantities when it was cultured for 6 days at 37 °C at the concentration of 9 mg/mL, shaking at 1000 r/min. The morphology of fibrils was successfully observed under transmission electron microscopy. α-synuclein fibrils are important materials for the establishment of PD models. The above results showed that a method for the rapid and efficient preparation of recombinant human α-synuclein fibrils was established， which provided important research materials for the establishment of animal models and cell models of PD. Related Articles | Metrics

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A screening system based on kanamycin resistance against protein splicing of the RecA intein of Mycobacteriun tuberculosis#br# #br# HU Jing-ping, JIANG Yu-ting, QI Xing-mei 2020, 37 (2):  101.  doi: 10.3969/j.issn.2095-1736.2020.02.101 Abstract ( 368 )   PDF   Save Mycobacterium tuberculosis harbors three inteins in three critical proteins. Post-translational removal of the inteins is required for function of the proteins.Thus, inteins are potential targets for antimycobacterial agents. It is very important to develop a high throughput screening system for the isolation of antimycobacterial drugs that interfere with protein splicing. Therefore, the RecA intein coding sequence of Mycobacterium tuberculosis was inserted into kanamycin-resistance gene so that functional antibiotic resistance was restored upon protein splicing. Western Blot and kanamycin plate assay showed that the kanamycin resistance in LB plate was in accordance with the intein splicing efficiency, which was capable of screening system for intein inhibitors. To examine the utility of this screen system, the growth of E.coli transformed with plasmids containing kanamycin-intein fusions was significantly slowed by cisplatin, which showed that cisplatin toxicity could be suppress protein splicing by intein overexpression. Related Articles | Metrics

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Teaching practice of cell biology in sino-foreign cooperative medical laboratory technology LIU Xiao-ying, CHEN Qi, LIU Gang, TENG Yan-bin, FAN Li-bin 2020, 37 (2):  104.  doi: 10.3969/j.issn.2095-1736.2020.02.104 Abstract ( 256 )   PDF   Save Cell biology course is instrumental for the students specializing in medical laboratory technology. Here, we put forward our practice and exploration of teaching experiences for the students based on Sino-foreign cooperation: teaching materials for strengthening the integration of Sino-foreign; teaching methods for striving variety and efficiency, changing the traditional teaching mode; teaching evaluation for emphasizing on the learning process and focusing practical teaching on manipulative ability development. And then we tried to arouse the enthusiasm of the students, promote bilingual teaching effectiveness and meet with the specific requirements of the courses. Generally, these attempts will benefit for students to lay a strong foundation in the study of other basic courses and specialized courses taught in foreign countries in the later stages. Related Articles | Metrics

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Applications of virtual slices system in botany experimental teaching DU Kun, FU Yuan-yuan, GUO Bin-hui, LUO Le, CHEN Yi-bing, ZHANG Biao, WEI Wan-hong 2020, 37 (2):  107.  doi: 10.3969/j.issn.2095-1736.2020.02.107 Abstract ( 200 )   PDF   Save There are many problems in traditional experimental teaching of botany, such as difficult preservation of glass slides specimens, difficult observation of plant dynamic development, requirement of a large number of microscopes for the microstructure learning and difficult to master the operating process of paraffin section. In order to solve these problems, we have researched and constructed a botanical virtual slicing system independently. The system includes digital full-scale glass specimens scanned by the automatic microscope, 3D virtual simulation resources of paraffin technology, and auxiliary teaching resources such as video, animation, test questions database. This system can be used to realize the functions of online observation learning, autonomous learning, experimental report submission, virtual examination and online communication under the access of different types of terminal devices. Through the implementation of the experimental teaching mode of "combination of virtual reality and reality”, physical experimental teaching resources and virtual simulation experimental teaching resources have been organically combined. As a result, this new teaching mode not only enriches the content of experimental teaching, effectively expands the time and space of experimental teaching, but also sufficiently stimulates interest in learning，improves the effect of experimental teaching, and achieves the whole process coverage for experimental examination. Related Articles | Metrics

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Application of research feeding comprehensive model in teaching  of biological separation engineering LI Meng-fei, ZHANG Zhen, SUN Ping, SI Huai-jun, YANG De-long 2020, 37 (2):  110.  doi: 10.3969/j.issn.2095-1736.2020.02.110 Abstract ( 288 )   PDF   Save Research feeding teaching (RFT), based on its advantages in many courses teaching, was applied in teaching of biological separation engineering， combining with experimental modes of comprehensive experimental teaching (CET) and open experimental teaching (OET), and then the teaching effects were analyzed through the test of theoretical knowledge and questionnaire of student investigation. The results showed that the experimental teaching mode of combining with RFT, CET and OET could effectively arouse students’ interesting to learn and communicate with others when compared to the models of OET and OET+CET, respectively. It could be beneficial for students to master the theory knowledge and improve the comprehensive application ability including: innovation, experimental operation, scientific paper writing and etc., and it could be worthy for popularization and application in the teaching of biological separation engineering and similar courses. Related Articles | Metrics

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Discussion on the importance of project-based learning in biology teaching by comparison of Chinese and American classroom teaching methods LIU Ya-jun, WANG Yun-sheng, ZHANG Yu-qiong, GAO Jun-shan, GAO Li-ping 2020, 37 (2):  113.  doi: 10.3969/j.issn.2095-1736.2020.02.113 Abstract ( 274 )   PDF   Save In order to meet the needs of an innovative country construction in China, the most colleges and universities are actively exploring the innovation of teaching methods, to fit the needs of innovative talented individualized teaching and differentiated training. This paper proposes the importance of project-based teaching approach to culture innovative talents by comparing the biology teaching methods between Chinese and American universities and the trial implementation of project-based teaching method in domestic university biology courses. It also analyzes the characteristics of the project-based teaching method and and the problems of the current implementation of the project education in domestic universities. It provides some reference for the reform of biology undergraduate education in colleges and universities in China. Related Articles | Metrics

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Reform on physiology experimental teaching under background of aeronautics, astronautics, and marine characteristics DANG Kai, JIANG Shan-feng, QIAN Ai-rong 2020, 37 (2):  116.  doi: 10.3969/j.issn.2095-1736.2020.02.116 Abstract ( 214 )   PDF   Save In order to meet the requirements of the development of higher education in our country under the new situation and cultivate innovative ability and practical ability of students, in combination with the university′s characteristics in aeronautics, astronautics and marine, the physiology experiment teaching team of School of Life Sciences of our university has carried out a series of reforms on physiology experiment teaching in the aspects of teaching idea, teaching system and system of assessment and evaluation. Practice shows that the implementation of physiology experiment teaching reform combined with aeronautics, astronautics and marine characteristics, and based on cultivation of innovative ability of students, has stimulated students′ interest in study and trained the students′ innovative consciousness and innovative ability, which plays a positive role in promoting the cultivation of high-quality innovative talents. Related Articles | Metrics

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Reflection on the renewal of teaching contents related to eukaryotic microorganisms in current microbiology textbooks LI Li, CHEN Suo, YU Zhi-he 2020, 37 (2):  119.  doi: 0.3969/j.issn.2095-1736.2020.02.119 Abstract ( 172 )   PDF   Save With the development of biological systematics, the classification of eukaryotic microorganisms was revised constantly. In this paper, based on the recent progress of fungal systematics, problems existing in the teaching contents of eukaryotic microorganisms in current microbiology textbooks were analyzed from the aspects of classification of eukaryotic microorganisms as well as rigorousness and scientificity of knowledge points. Combining with our own teaching reform and practice, suggestions on the revision of knowledge points and the framework of knowledge system were then put forward. The aim of this paper is to improve the textbook structure and content of microbiology, to promote the integration of teaching content and disciplinary frontier and to improve teaching effect. Related Articles | Metrics

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Practice of blending learning reform of biochemistry course based on THEOL platform GAO Yuan, WU Xiao-chun, LIU Xia, LI Long-feng, YANG De-long, SI Huai-jun 2020, 37 (2):  123.  doi: 10.3969/j.issn.2095-1736.2020.02.123 Abstract ( 261 )   PDF   Save Biochemistry is one of the most important basic courses in the field of life sciences but is difficult to learn due to too many knowledge points in this course. The development of information and network technology has brought new opportunities and challenges to the reform of higher education. The "Tsinghua education online (THEOL)" network teaching platform provides a new opportunity for the mixed teaching reform of this course. This paper discusses the author′s experience in the application of THEOL teaching platform during the teaching reform of biochemistry. It systematically describes the advantages of THEOL teaching platform in promoting the innovation of teaching concepts, ensuring the live update of teaching knowledge, improving students′ initiative and participation, tracking after-school learning, promoting the reform of curriculum assessment methods, and facilitating integration and utilization of the network resource. In practice, the blending learning can effectively promote college students to think and improve their ability to ask, analyze and solve problems. This study aims to provide a basis for the reform and research of biochemistry curriculum. Related Articles | Metrics

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Construction and application of open-ended item bank  in natural pharmaceutical chemistry LU Wei-li, LIU Zhi-cheng, LI Ning, CHENG Wen-ming, WU Ting-ni 2020, 37 (2):  127.  doi: 10.3969/j.issn.2095-1736.2020.02.127 Abstract ( 236 )   PDF   Save The examination is a scientific and objective way to assess the quality of teaching and the students′ learning outcomes. The construction of the item bank is an important part of the reform of the college course examination system. It could achieve the separation of teaching and testing, and the scientification and standardization of the test. This paper analyzes the problems existing on the current examination forms of theoretical courses in the university and the teaching process of natural pharmaceutical chemistry course. The web-based construction of open-ended item bank of natural pharmaceutical chemistry is well expounded. The experience and advantages of the open-ended item bank construction are summarized from various aspects， which include the aim, measures, and application. The issues which should be handled are pointed out for the further optimization of the item bank. It is seen that the open-ended item bank has positive effects on improving the quality of teaching and the ability of students′ self-study. Related Articles | Metrics