Table of Content

18 October 2021, Volume 38 Issue 5 Previous Issue    Next Issue

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hotobiocatalytic reaction design and its biosynthetic applications ZHANG Wuyuan, YUAN Bo, QU Ge, SUN Zhoutong 2021, 38 (5):  1.  doi: 10.3969/j.issn.2095-1736.2021.05.001 Abstract ( 896 )   PDF   Save Photobiocatalysis is emerging rapidly as an interdisciplinary technology. It combines the advantages of photocatalysis and biocatalysis, and exerts huge potentials in biosynthesis. Through natural biomimetic design, the photobiocatalytic approach can offer alternatives to conventional chemical synthesis and integrate multiple factors involved in the formation and transfer efficiency of functional groups, atom economy and environmental factors. As such, the photobiocatalysis can be used to expand the reaction horizons, a major limitation of natural enzymes. It is of great significance to establish new synthetic pathways with high efficiency and low consumption. In recent years, the photobiocatalysis has been sucessfully used to catalyze organic reactions including carbon-carbon, carbon-oxygen, carbon-nitrogen, carbon-halogen bond formation, etc. It has shown unique merits in catalytic activity, atom economy, selectivity and expansion of substrate scopes. This review focuses on the present advances of photobiocatalysis in organic synthesis, and analyzes the potentials of its application as well as the technical bottlenecks to be addressed. We also expect to provide references for further development of green chemical synthesis technology via the use of photobiocatalysis. Related Articles | Metrics

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The effect of hbae1.1 gene on hemoglobin production in zebrafish knocked out by CRISPR/Cas9 MENG Lin, CHEN Liangbiao 2021, 38 (5):  12.  doi: 10.3969/j.issn.2095-1736.2021.05.012 Abstract ( 479 )   PDF   Save This study used the CRISPR/Cas9 technology to knock out the hbae1.1 gene and obtained the homozygous mutants of hbae1.1 gene. The effect of hbae1.1 gene deletion on hemoglobin production in zebrafish was investigated. The knockout target was designed according to zebrafish hbae1.1 gene, and the corresponding gRNA was prepared, gRNA and Cas9 protein were mixed in a certain proportion and injected into zebrafish fertilized egg at a cellular stage by microinjection. After T7E1 endonuclease digestion, sequencing and sequence comparison, it was detected that the hbae1.1 gene was successfully knocked out. By mating with wild type and internal crossover, the F2 homozygous mutant was successfully obtained. Comparing the o-Dianisidine staining of embryos produced by the homozygous mutant with hbae1.1 gene deletion and wild type, the results showed that the hemoglobin content of the mutant was significantly reduced compared with the wild type. Studies have shown that the deletion of hbae1.1 gene would have a certain effect on the production of zebrafish hemoglobin. At the same time, the study of hbae1.1 gene provided a certain basis for understanding the occurrence and development of fish hemoglobin. Related Articles | Metrics

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Prokaryotic expression and mass spectrometry determination of IAG gene in Portunus trituberculatus TUO Ping, XIE Xi, YU Guohong, ZHU Dongfa 2021, 38 (5):  17.  doi: 10.3969/j.issn. 2095-1736.2021.05.017 Abstract ( 325 )   PDF   Save Based on the known insulin-like androgenic gland hormone (IAG) gene in Portunus trituberculatus nucleotide sequence, the ORF region of Pt-IAG was amplified, liganded into different prokaryotic vectors, including pET-22b, pET-28a and pET-28a-sumo, and then transformed into Escherichia coli BL21 (DE3) and Rosetta (DE3) strains, respectively. The His-tag labeled IAG recombinant fusion protein was induced by isopropyl-β-D-thiogalactoside (IPTG), and the SDS-PAGE found that only the pET-28a-sumo-IAG could be detected, and the IAG transformed into the Rosetta (DE3) strain was highly expressed. Further exploration of the condition of this Rosetta-pET-28a-sumo-IAG system showed that the IAG recombinant fusion protein was most efficiently expressed when induced by 0.6 mmol/L of IPTG at 16 ℃ for 16 h. The fusion protein was mainly expressed in soluble form and was further purified by HisTrap HP column. Western Blot analysis showed that the fusion protein could be recognized by mouse anti-His-tag. The purified protein was further analyzed by mass spectrometry, and two peptides could be matched to the B chain and A chain, respectively, which indicated that the recombinant fusion protein was successfully obtained. Related Articles | Metrics

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Depletion of SOCS1a causes hepatic oxidative stress in zebrafish DAI Ziru, KONG Yan, WANG Pei, LOU Qiyong, LI Dongliang 2021, 38 (5):  23.  doi: 10.3969/j.issn. 2095-1736.2021.05.023 Abstract ( 316 )   PDF   Save To investigate the effect of SOCS1a on liver oxidative stress in zebrafish, the liver tissues of zebrafish were analyzed by transmission electron microscopy (TEM), the activity of antioxidant enzymes and transcriptome between the SOCS1a-deficient adult zebrafish and their control siblings after feeding with high fat food and normal food for 6 weeks was assayed. Abnormal expansion, decreased ridge density of mitochondria and lipid droplet accumulation were observed in the liver of SOCS1a-deficient zebrafish. Under normal feed feeding conditions, the activities of superoxide dismutase (SOD) and glutathione reductase (GR) were lower in the liver of SOCS1a mutant compared with their control siblings by 27.813 and 3.879U/mg(prot), respectively. Under high-fat conditions, the SOD and GR activities were lower in the liver of SOCS1a mutant compared with their control siblings by 14.015 and 3.865 U/mg(prot), respectively. Transcriptome analysis showed the oxidative stress-related signaling pathway was significantly upregulated in the SOCS1a-deficient zebrafish. Overall, the SOCS1a knockout in zebrafish caused oxidative damage and oxidative stress, and the oxidative stress was more intense under the induction of high fat food. Related Articles | Metrics

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CRISPR/Cas9 construction of zebrafish igf2bp3 mutant and sex analysis of offspring XU Weiwei, CHEN Liangbiao 2021, 38 (5):  28.  doi: 10.3969/j.issn.2095-1736.2021.05.028 Abstract ( 539 )   PDF   Save Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) regulates mRNA transcription and translation by binding to the target mRNA coding region, and it plays important roles in the processes of cell polarization, movement, morphogenesis, metabolism, proliferation and differentiation. Due to the lack of available mutant models in mammals, this study used CRISPR/Cas9 technology to construct igf2bp3 gene zebrafish mutants. By microinjecting two gRNA and Cas9 proteins into the single cell stage of zebrafish embryos, PCR and Sanger sequencing confirmed that the igf2bp3 gene knockout strain with a deletion of 1 513 bp was successfully constructed. Fluorescence quantitative PCR results showed that the igf2bp3 gene was expressed in all tissues examined of wild-type adult zebrafish, but the highest expression tissue was ovary, the number of males in homozygous zebrafish and wild-type zebrafish was significantly more than that of females, and the proportion of males and females was close to 0.1, indicating that the igf2bp3 gene might play a role in zebrafish gonad development. The result would lay a foundation for studying the sex-determining genes of zebrafish, and provided new ideas for obtaining fast-growing male fish in the fish farming industry. Related Articles | Metrics

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Construction of CRISPR/Cas9 system targeting mouse Tyr geneand analysis of targeting effectiveness YUE Pengpeng, YANG Guangyu, WANG Tianxian, FU Can, XIAO Yiran, YU Honghao 2021, 38 (5):  34.  doi: 10.3969/j.issn.2095-1736.2021.05.034 Abstract ( 348 )   PDF   Save The TYR gene encodes tyrosinase. This gene mutation affects the production of melanin and is the genetic cause of human albinism. In this study, databases such as OMIM, ExAC and ClinVar were used to screen the strong pathogenic mutation site of human TYR gene. The site located on the mouse genome according to human strong pathogenic mutation site was found by protein sequence comparison analysis. Then three guide RNAs (small guide RNAs, sgRNAs) were designed based on the DNA sequence of located site and the principle of CRISPR/Cas9 gene targeting. The construction of sgRNA expression vectors, co-transfection of N2a cells, drug screening, PCR product sequencing and TA clone sequencing analysis were performed for the target efficiency analysis of the three sgRNAs. TA clone sequencing analysis results showed that random insertion or deletion mutations of bases occurred at all three sites, and the mutation efficiency was 100%, indicating that this study successfully constructed a highly efficient CRISPR/Cas9 system targeting mouse Tyr gene for simulating the strong pathogenic mutation of human albinism. The CRISPR/Cas9 gene editing system has laid the foundation for further preparation of Tyr genetically engineered mouse, in-depth study of the pathogenic mechanism of TYR gene mutation and the search for reliable treatment methods. Related Articles | Metrics

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Cloning of fusion gene and its mutants by double fragments ligation WANG Yuan, CHENG Yingying, MA Mengqi, LIANG Mingxing, CHEN Huabo 2021, 38 (5):  39.  Abstract ( 266 )   PDF   Save In order to reduce random mutation that was accompanied by DNA amplification in vitro, PCR was only used to attach a short linker sequence to the 5′ end of CDK2 (cyclin dependent kinase 2). Because of the interference of double BamHⅠ sites, cyclin E and CDK2 sequences could not be inserted into vector in an orderly way. Therefore, two gene fragments were linked together into vector, so as to construct the fusion gene. Employing similar strategy, CDK2 mutant sequence was used to displace the corresponding wild type sequence of the fusion gene in order to rebuild its mutant. After transformation of competent Escherichia coli with both double fragments ligation product, several colonies were screened out and some target clones were identified successfully. Double fragments ligation broke the rigorous demand of restriction sites of step by step ligation, and expanded the application of enzyme cleave-ligation in DNA assembly. On these grounds, it was convenient to clone fusion gene and its mutant by replacement of DNA elements with the assistance of the identified recombinant plasmid. Related Articles | Metrics

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Construction of enhanced expression vector based on 5′UTR and its downstream sequence in Corynebacterium glutamicum FANG Qiuwu, GAO Xiong, SUN Manman, LIU Xiuxia, LI Ye, YANG Yankun, BAI Zhonghu 2021, 38 (5):  43.  Abstract ( 218 )   PDF   Save Several endogenous 5′UTRs (5′-untranslated region) and their downstream sequences with highest protein abundance were firstly identified from the genome of Corynebacterium glutamicum CGMCC1.15647, and these 5′UTRs and their downstream sequences with two strong promoters PH36 and Ptacwere used to construct monocistronic (MEM) and bicistronic expression model (BEM). In both MEM and BEM, the 5′UTR and its downstream sequence significantly enhanced the expression ability of these promoters. Among them, the highest expression intensity of these vector, pTac-B2826-EGFP, was about 3.6 times that of the positive expression vector pTac-Positive. Several vectors with high expression ability were selected to express the variable domain of heavy chain of heavy-chain antibody (VHH) protein in Corynebacterium glutamicum. In the shake flask fermentation culture, the secreted expression of the protein VHH reached 85.4 mg/L. All these works provided several new vectors with strong expression ability for heterologous protein expression of Corynebacterium glutamicum. Related Articles | Metrics

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Exploring the mechanism of AmPR-10 nuclease activity based on the homologous protein sequence alignment WANG Jue, HU Lili, LI Guilan, WU Na, ZHANG Yumin 2021, 38 (5):  48.  doi: 10.3969/j.issn.2095-1736.2021.05.048 Abstract ( 210 )   PDF   Save The AmPR-10（Astragalus membranaceus pathogenesis-related protein-10）plays an important role in the development and disease resistance of Astragalus membranaceus. The results showed that the AmPR-10 expressed in E. coli could display nuclease activity. Comparing the amino acid sequence of AmPR-10 with its seven homologous proteins which had been proved to have nuclease activity, we found that there were four highly conserved regions in the AmPR-10 gene (V14-V24, V44-K55, T64-K70 and Y83-G88 ). The first conserved region and the C-terminal α-helix formed a strong hydrophobic region in space to stabilize the structure of protein cavity, which was conducive to the function of AmPR-10 in resisting invasion. In addition, by molecular docking and amino acid site mutation, the Tyr at position 83 in the fourth conserved region was discovered to be the key site for AmPR-10 nuclease activity, and its change would affect the stability of target protein binding with substrate, while the 140 Gly in the non-conservative region could be used as a reference site for gene evolution. When Gly was mutated to Asn, Val and Trp, the binding free energy was decreased. The above results have theoretical guiding significance for further understanding and optimizing of the nuclease activity of AmPR-10. Related Articles | Metrics

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Genome-wide identification and analysis of the TIFY gene family in Dendrobium officinale Kimura et Migo during protocorm development HU Rui, GUO Jianxiu, GUO Xiaoqiang, CHEN Fengying, WANG Wanjun 2021, 38 (5):  53.  doi: 10.3969/j.issn. 2095-1736.2021.05.053 Abstract ( 283 )   PDF   Save The identification of TIFYs in Dendrobium officinale is not particularly clear. In this study, 20 D. officinale TIFY(DoTIFY) genes were identified. According to the phylogenetic analysis of TIFYs from D. officinale, Arabidopsis thaliana, Oryza sativa, Gossypium arboretum and Helianthus annuus, DoTIFYs were divided into four categories, JAZ, PPD, ZIM, and TIFY. RNA-seq analysis during the 5 stages of D. officinale protocorm development revealed 11 differentially expressed DoTIFY genes and these genes might be involved in the development of D. officinale protocorm. The qPCR analysis showed that the expression levels of DoJAZ3, 8, 5, and DoJAZ6 increased significantly during P1-P7 stages of D. officinale, indicating that they might play roles in P1-P7 stages. The result help us for the further research on the mechanism of protocorm development and related breeding improvement of D. officinale. Related Articles | Metrics

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Regulation of autophagy on the growth and metabolism of Pichia pastoris using different carbon sources LU Wenyi, ZHAN Chunjun, LIU Xiuxia, ZHAN Jinling, YANG Yankun, BAI Zhonghu 2021, 38 (5):  59.  doi: 10.3969/j.issn.2095-1736.2021.05.059 Abstract ( 319 )   PDF   Save Pichia pastoris has become one of the most popular eukaryotic expression systems for its strong promoter of alcohol oxidase Ⅰ (AOX1), PAOX1. However, the growth of the cell in methanol (short for MeOH) is obviously slower compared to glycerol. And glycerol can inhibit methanol metabolism. In order to clarify the mechanism how carbon sources affect yeast growth and metabolism, the effects of different carbon sources on Pichia pastoris were compared. All experimental results showed that the change of metabolic substrate and cell growth were involved in autophagy. When the carbon source was changed to methanol, the expression of Atg8 was up-regulated, while Atg30 was down-regulated. In methanol, higher level of macroautophagy resulted in slower cells growth, inhibited pexophagy and increased activity of AOX1. The change of autophagy in Glycerol transporter 1 knockout Pichia pastoris (short for P. pastoris ΔGT1) was compared with that in wild-type and found that the change of the expression level of Atg8 and Atg30 was smaller in P. pastoris ΔGT1, which conformed to the property that carbon source suppression was released in P. pastoris ΔGT1. It was further demonstrated that the autophagy was one of the main ways that carbon sources changed the cell growth and metabolism. This paper further analyzed the mechanism of methanol metabolism regulation of Pichia pastoris from the perspective of cell autophagy, and provided a new direction and theory to improve utilization of methanol and expression of heterogeneous proteins. Related Articles | Metrics

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Effects of different diets on culture performance,physiological metabolism and biochemical composition of ridgetail white prawns, Exopalaemon carinicauda HE Xianlin, LIU Meimei, DONG Zhiguo, WAN Xihe, WU Xugan 2021, 38 (5):  66.  doi: 10.3969/j.issn.2095-1736.2021.05.066 Abstract ( 251 )   PDF   Save Ridgetail white prawns (Exopalaemon carinicauda) is an important marine aquaculture species in China. At present, E. carinicauda is mainly fed with traditional diets (trash fish and wheat meal mixture) during the whole culture process. In this study, we investigated the effect of two feeding modes (formulated diets, traditional diets) on the growth culture performance, physiological metabolism and biochemical composition of pond-reared E. carinicauda. The result showed that the feed conversion ratio (FCR) of E. carinicauda fed with formulated diets was significantly lower than that with the traditional diets treatment (P<0.05). The activity of glutamate-pyruvic transaminase (GPT) and superoxide dismutase (SOD) and the contents of blood urea nitrogen (BUN) in hepatopancreas of formulated diets treatment were significantly higher than those in traditional diets treatment (P<0.05). The contents of moisture in muscle of formulated diets treatment were lower than those in traditional diets treatment, while the contents of ash in muscle were higher than those in traditional diets treatment (P<0.05). The contents of monounsaturated fatty acid (MUFA) , polyunsaturated fatty acid (PUFA) and n-6 polyunsaturated fatty acid (n-6PUFA) in hepatopancreas of formulated diets treatment were significantly higher than those of the traditional diets treatment (P<0.05) . The contents of essential amino acids (EAA) and total amino acids (TAA) in muscle of formulated diets treatment were significantly higher than those of the traditional diets treatment. Related Articles | Metrics

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Study on the blood compatibility of biomimetic polymer film mimicking the locust wing FANG Yan, SUN Gang, QIU Zekui, LAN Lan, LONG Biao, HUANG Junjiang 2021, 38 (5):  72.  doi: 10.3969/j.issn.2095-1736.2021.05.072 Abstract ( 235 )   PDF   Save Using locust wing as template and polydimethylsiloxane (PDMS) as substrate, biomimetic polymer films were prepared by means of soft etching and dual transcription, and the blood compatibility of the biomimetic film surface was evaluated. Based on the results, the micro-morphology of wing surface was replicated successfully on the biomimetic film, which exhibited high resistance against water (contact angle 141.3°-147.6°) and blood (contact angle 119.8°-126.3°) as well as fine blood compatibility. On the surface of biomimetic film mimicking the wing of Oxya chinensis, Chondracris rosea rosea and Locusta migratoria manilensis, the amount of platele adhesion were 3.06×104, 2.83×104 and 0.95×104 ind./cm2, respectively, remarkably lower than that (10.89×104 ind./cm2) on the CK film. On the surface of biomimetic film mimicking the wing of L. migratoria manilensis, the amount of platele adhesion was the lowest, just 8.7% of the CK; meanwhile, the platele kept intact form, was not activated, without pseudopodia, deformation, and aggregation, implying better anticoagulant function and longer dynamic coagulation time. On the surface of biomimetic film, the hemolysis rate was lower than 5%, complying with China’s standard for medical polymer materials. The multiple hierarchical structure improved the interaction of blood cells and micro unit. The micro-nano effect prevented blood cells from mechanical injuring, adhering, and spreading. The coagulation cascade and microthrombus formation were markedly inhibited. The results might provide novel idea and method for fabrication of innovative medical engineering materials. Related Articles | Metrics

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Comparative analysis of nutritional components of Spirulina platensis from Erdos plateau and five common protein foods WANG Zhizhong, SUN Junshe, MU Jie, HU Jing, GONG Donghui, BAO Yulan 2021, 38 (5):  77.  doi: 10.3969/j.issn.2095-1736.2021.05.077 Abstract ( 316 )   PDF   Save In order to explore the unique nutritional components of Spirulina platensis in Ordos plateau, the nutrient contents between 10 g Spirulina and one 60 g egg, 250 g milk, 30 g soybean milk powder, 100 g carp, and 100 g grass carp were analyzed comparatively. The results showed that the indicators of the six foods were significantly different (P<0.01). The protein content in 10 g spirulina was less than that in two kinds of fish and was close to that in other food. The content of energy, fat and carbohydrate was lower, among which, the fat content in two kinds of fish and the carbohydrate content in 250 g milk and 30 g soybean milk powder were higher. Except for 250 g milk, which had significantly higher calcium content than other foods, there was not much difference in the sodium, potassium, magnesium, and phosphorus contents in the six kinds of foods. The iron content in 10 g Spirulina was much higher than that in other foods, reaching 97.11% (male) and 72.83% (female) of the recommended intake; the zinc and selenium content of 100 g carp and 30 g soybean milk powder were the highest, and the vitamin B1 content and B6 content of 6 foods were slightly different. The contents of vitamin A, B2 and B12 in 10 g Spirulina were the highest and accounted for 38.00% (male) and 43.43% (female), 35.43% (male) and 41.33% (female) and 458.33% of the recommended intake, respectively. The folic acid content in 10 g Spirulina was about 1/3 and 1/2 of the egg’s and the milk’s, respectively. Among the six kinds of food, the content of vitamin B3 in two kinds of fish was the highest and accounted for 20% of the recommended intake. Related Articles | Metrics

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Research on isolation, culture and multiple differentiation potential of human umbilical cord mesenchymal stem cells #br# #br# CHEN Feng, YANG Min, LI Yanjie, PENG Ling, HUANG Huaxin, PENG Yun 2021, 38 (5):  82.  doi: 10.3969/j.issn. 2095-1736.2021.05.082 Abstract ( 314 )   PDF   Save The method of isolation and culture of human umbilical cord mesenchymal stem cells (hUCMSCs) was established, and their biological characteristics and multi-differentiation potential were identified. Umbilical cord tissues from healthy maternal in full-term cesarean section were collected and primary culture was performed by tissue explants adherent method.The expression of cell surface markers and the pluripotent related genes were detected by flow cytometry and RT-PCR, respectively. Multi-differentiation capacity was identified by adipogenic, osteogenic and chondrogenic differentiation. Results showed that a lot of cells were appeared around the umbilical cord tissue piece on the 14th day, the cells highly expressed mesenchymal stem cell surface markers CD44 and CD105, but negative for hematopoietic cell surface markers CD34 and CD45. Moreover, the cells also expressed pluripotent related genes Oct4 and Nanog. The cells potential to differentiate into adipocytes, osteocytesand chondrocytes was identified by tissue staining and RT-PCR. In conclusion, hUCMSCs can be proliferated and cultured in vitro, expressed pluripotent related genes.And they had the multi-directional differentiation potentiality and could be used as seed cells for tissue engineering. Related Articles | Metrics

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Research progress on the anti-tumor function of tubeimosides YANG Zhihua, RUAN Zijing, LIAO Hai, HUANG Xinhe 2021, 38 (5):  86.  doi: 10.3969/j.issn. 2095-1736.2021.05.086 Abstract ( 522 )   PDF   Save Natural products are important sources of anti-tumor drugs. As a natural product of the cucurbitaceae fritillary family, tubeimosides (TBMs) has important medicinal values and has been widely used in the prevention and treatment of many diseases, including cancer. The main active ingredients of TBMs are saponins, and 16 saponins have been isolated so far, of which, TBM I, II and III are the most studied active ingredients. Recent studies have shown that TBMs vulgaris have anti-tumor activity in different stages of canceration. The anti-tumor mechanisms of TBMs include inhibiting the growth and proliferation of cancer cells, inducing cancer cell differentiation, apoptosis, autophagy, inhibiting tumor cell angiogenesis, invasion and metastasis, inhibiting inflammation, and so on. This review summarized the latest information on the anti-tumor effect and preclinical research of TBMs and explored the application prospects of TBMs in cancer prevention and treatment. It may provide a foundation for the further development and utilization of TBMs and TBMs-related medicines. Related Articles | Metrics

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Research progress of the effects of light on secondary metabolism of higher fungi ZHANG Zongyuan, PAN Mengshi, GUO Wenyang, YUE Dandan, ZHANG Yingtao, QI Landa 2021, 38 (5):  91.  doi: 10.3969/j.issn. 2095-1736.2021.05.091 Abstract ( 359 )   PDF   Save Fungal secondary metabolites ( SMs) have diverse bioactivities, and have been utilized in different fields including agriculture, food industry, medicine. Most of the secondary metabolites with novel structure and unique activities discovered in recent year are also derived from fungi. Therefore, the regulation of fungal secondary metabolism has been attracted much attention. As an important environmental factor in the growth of fungi, light has an important influence on cell development and regulation of metabolic synthesis.Light signals are converted into biological signals through photosensitive proteins in fungal, thereby the growth and secondary metabolism of fungal are regulated, which is of great research significance. Recent researches on the photobiological studies of fungi were analyzed in this review paper. From the perspective of secondary metabolism biosynthesis, this article summarized the effects of light on the synthesis of fungal natural active substances, and elaborated the molecular mechanism of light-regulated fungal secondary metabolism from epigenetics, global regulation and pathway specificity. Finally, the existing problems and application prospects were discussed and prospected. Related Articles | Metrics

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The mechanism and research methods of insect degradation of plastics TANG Qihe, DONG Zhixiang, LI Huanyuan, CHEN Yifei, GUO Jun 2021, 38 (5):  96.  doi: 10.3969/j.issn.2095-1736.2021.05.096 Abstract ( 365 )   PDF   Save Starting from the key point of insect degradation plastics, this paper focuses on the review of insect species and the mechanism of eating degradation plastics. It is found that there are 14 types of insects eating plastic in the world, and the degradation of plastics by some insects is due to their intestinal microorganisms. At present, the research methods of insect degradation plastics include product analysis, stable isotope tracing, bacterial culture and metagenomics. Some problems in this field and future research directions are put forward. It is hoped that this paper can provide an overview of insects based strategies on degradation of environmental plastic pollution. Related Articles | Metrics

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Research on effects of selenium on the uptake and transfer of Cd,As and Hg in rice ZHAZHANG Yiwen, DONG Changru, LIU Xiaoqiang, ZHANG Wei, PAN Dandan, FAN TingNG Yiwen, DONG Changru, LIU Xiaoqiang, ZHANG Wei, PAN Dandan, FAN Ting 2021, 38 (5):  101.  doi: 10.3969/j.issn. 2095-1736.2021.05.101 Abstract ( 249 )   PDF   Save Among trace metals, cadmium (Cd) , arsenic (As) and mercury (Hg) are classified as the most harmful contaminants in farmland to many organisms including plants, animals and humans. Rice is a staple food which is consumed by half population of the world. Due to longer growth period, rice plant can easily absorb and accumulate the trace metals from soil. Selenium (Se) is an essential nutrient for human beings and animals. Appropriate doses of selenium were found to promote rice growth, and improve of rice yield and quality. Moreover, selenium is considered to be an uptake inhibitor of heavy metals in rice. In recent years, most studies have focused their attention on the antagonism between heavy metals and selenium in the growth of rice. Effects of selenium on the absorption, transport and detoxification mechanisms of cadmium, arsenic and mercury in rice were reviewed, which could provide a theory basis and feasible measure for the researches to reduce heavy metals and improve selenium level in rice grains. Related Articles | Metrics

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Microenvironment signaling factors of intestinal stem cells provided by Paneth cells LI Yanli, GUO Yuhui, LIU Yu, XIONG Zhengguo, ZHANG Changcheng, DUN Yaoyan 2021, 38 (5):  105.  doi: 10.3969/j.issn.2095-1736.2021.05.105 Abstract ( 264 )   PDF   Save The microenvironment composed of cells adjacent to intestinal stem cells （ISCs） is key to the function of ISCs by providing a variety of essential signaling factors that regulate important signaling pathways for proliferation and differentiation in ISCs. Paneth cells are important providers of ISCs microenvironmental signaling molecules, and they can provide Wnt, Notch, EGF, mTORC1 and other related signaling factors for ISCs to maintain the balance of proliferation and differentiation. The signaling factors secreted by the Paneth cell are summarized here, to provide some ideas for the study of interaction between Paneth cells and ISCs, and the treatment of some intestinal epithelial homeostasis disorders. Related Articles | Metrics

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Optimization of the fermentation process and preliminary study of catalytic conversion of β-D-glucuronidase from Bacillus subtilis JY24 strain GAO Shufeng, KONG Lihua, LEI Ping, ZENG Fajiao, WANG Shengping, GONG Ping, ZHOU Xiaoling, LIU Huizhi 2021, 38 (5):  110.  doi: 10.3969/j.issn.2095-1736.2021.05.110 Abstract ( 224 )   PDF   Save In order to improve the enzyme quantity and activity from microbial strains, shorten fermentation time of enzyme production, this article aimed to study the optimization of fermentation process and preliminary catalytic conversion of β-D-glucuronidase from Bacillus subtilis, JY24 strain. Culture conditions for the production of β-D-glucuronidase from Bacillus subtilis JY24 strain were optimized by single factor method; the compositions of culture medium and conversion of baicalin were respectively studied by orthogonal design and HPLC. The result showed that the optimal culture conditions were: fermentation time, 42 h; rotational speed, 240 r/min; 50 mL culture in 500 mL liquid volume; initial culture medium, pH 7.0; temperature, 35 ℃； inoculation amount, 4％. The optimal compositions of medium were: sucrose, 8.0 g/L; yeast extract, 11.0 g/L; KH2PO4 , 0.38 g/L; K2HPO4 , 0.38 g/L; CaCl2 , 0.27 g/L; KNO3, 0.20 g/L; tween-20, 2.0 mL/L; corns steep, 1.0 mL/L; baicalin, 1.5 g/L. Under the optimized fermentation process, the enzyme activity of β-D-glucuronidase of Bacillus subtilis JY24 strain could reach 935.50 U/mL, which was 25.68 times higher than that before optimization, and the fermentation time for enzyme production was greatly shortened by 2.25-12.25 d. The preliminary results of catalytic conversion showed that the conversion rate of baicalin was 31.20%. Related Articles | Metrics

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Application of stepwise guiding teaching strategy in genetic engineering pharmaceutics module LIU Juanjuan, FANG Zemin, YUAN Jing, XIAO Yazhong 2021, 38 (5):  116.  doi: 10.3969/j.issn. 2095-1736.2021.05.116 Abstract ( 219 )   PDF   Save Based on the genetic engineering pharmaceutics module of the biotechnological pharmaceutics course, by expanding teaching ideas and reasonably organizing teaching contents, a stepwise guiding teaching strategy was developed. In the foundation stage, bilingual and interactive teaching based on teaching the basic technology and theory of genetic engineering pharmaceutics was carried out to establish a consolidated knowledge background and further cultivate students’ learning consciousness. In the advanced stage, the production design course was introduced to connect the theory and practice to cultivate students’ pharmaceutical process innovation ability. In the ascending stage, the genetic engineering pharmaceutics innovation experiments were set up to cultivate students’ innovation abilities in drug research and development. Results showed that stepwise guiding teaching was of good effect through the bilingual teaching and research progress teaching of principles of genetic engineering pharmaceutics, combined with the production design course and biotech drug research practice. Related Articles | Metrics

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The path and practice of veterinary pathology curriculum development from excellent course to first-class course TU Jian, SONG Xiangjun, SHAO Ying, LIU Hongmei, QI Kezong 2021, 38 (5):  120.  doi: 10.3969/j.issn. 2095-1736.2021.05.120 Abstract ( 278 )   PDF   Save As a rapidly developing curriculum category, life science is a general education curriculum system with multiple themes and perspectives, including science, humanities and social care. How to develop life science courses from excellent courses to first-class courses and what is the realization path are hot issues in the teaching reform and exploration of life science courses in colleges and universities at present. This paper focuses on the differences between excellent courses and first-class courses in course objectives, teaching concepts, teaching methods and ideological and political elements, and takes veterinary pathology course, a branch of life science courses, as an example. It describes the innovative path and construction practice of how the course develops from excellent course to first-class course from four aspects: the new orientation of course objective, the new transformation of teaching idea, the new reform of teaching method and the new integration of ideological and political elements. The aim is to provide reference for the construction of other life science courses. Related Articles | Metrics

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Teaching exploration of general education course microbiology in colleges and universities CAO Yueqing 2021, 38 (5):  124.  doi: 10.3969/j.issn.2095-1736.2021.05.124 Abstract ( 261 )   PDF   Save In order to make students in non-biological majors understand the beneficial and harmful microorganisms around them, we have established a general course “Microbes around”. The content of the course involved common microorganisms in five fields, including medical science, medicine, food, agriculture and environment. The teaching modes, such as in-class and after-class experiments, class discussions, flipped classroom, combined online and offline teaching, were adopted to make students more positive and arouse their study enthusiasm. Multiple assessments were adopted in the course evaluation, and the assessment content ran through the whole teaching process. Teaching evaluation of students showed that this course was popular with students in terms of content setting and teaching mode, and achieved wonderful teaching effect. Related Articles | Metrics

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Construction of molecular biology virtual simulation experiment project under the background of crossing art & science TANG Haifeng, LI Jiawei, LIU Yan, WU Sihao, FAN Linyuan, Teng Lirong, CUI yinqiu 2021, 38 (5):  127.  doi: 10.3969/j.issn.2095-1736.2021.05.127 Abstract ( 245 )   PDF   Save The development of molecular archaeology virtual simulation experiment project facing to both liberal arts and science major can not only make up for the shortage of practical learning opportunities of molecular biology for undergraduates majoring in archaeology, but also build a more professional practical learning platform for undergraduates majoring in biology. “Ancient DNA research” which could not be taught in the off-line classroom was eventually chosen as a content carrier after in-depth analyzing of the university’s discipline and technical advantage. The knowledge system and content structure were carefully designed according to the learning needs of both liberal arts and science students. The better teaching effect was achieved by designing differentiated teaching objective for liberal arts and science students and adopting the teaching tactics of “to strengthen practice in classroom after online learning”. Related Articles | Metrics