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1. Efficient production of ε-poly-L-lysine from L-lysine in <i>Streptomyces albulus</i> by L-lysine importer identification and overexpression | |||
Zhang Jiawei,Chen Xusheng | |||
Biology 11 March 2024 | |||
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Abstract:ε-Poly-L-lysine (ε-PL) is a natural cationic antimicrobial peptide widely recognized for its potential in food preservation. Current production methods predominantly rely on de novo synthesis utilizing substrates like glucose, with some studies exploring the supplementation of lysine to enhance fermentation efficiency. However, lysine transporters have not been investigated. In this study, we employed genomic and bioinformatic strategies to pinpoint seven potential lysine transporters in <i>S. albulus</i> . Gene knockout experiments confirmed <i>GL6157</i> as a functional lysine transporter. Overexpression of lysine transporters with different promoters increased lysine consumption by 19.3% and ε-poly-lysine yield by 10% during fermentation | |||
TO cite this article:Zhang Jiawei,Chen Xusheng. Efficient production of ε-poly-L-lysine from L-lysine in <i>Streptomyces albulus</i> by L-lysine importer identification and overexpression[OL].[11 March 2024] http://en.paper.edu.cn/en_releasepaper/content/4762469 |
2. Improving natamycin production of <i>Streptomyces gilvosporeus</i> by ARTP mutagenesis combined with 2-deoxyglucose | |||
Wen Xiao,Liang Wang,Hongjian Zhang,Xunsheng Chen,Jianhua Zhang | |||
Biology 01 March 2024 | |||
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Abstract:Natamycin is a polyene macrocyclic antibiotic extensively used in food, medical, and agricultural industries. However, due to high cost and low production efficiency, the current production level fails to meet the growing market demand. Therefore, it is necessary to establish a suitable strain breeding method to improve the production efficiency of natamycin-producing strains. Here, we first assessed the breeding efficiency of 16 different mutagenesis methods and found that the combination of Atmospheric and Room Temperature Plasma (ARTP) with 2-deoxyglucose tolerance exhibited the highest breeding efficiency. After two rounds of screening with the optimal strategy, a high-producing mutant, <i>Streptomyces gilvosporeus</i> AG-2, was obtained. This strain exhibited an enhanced natamycin production of 1.53 g/L, 80% higher than the parent strain <i>S. gilvosporeus</i> ATCC 13326. Further research reveals that the high production of AG-2 may be due to the changes in the transcription levels of the natamycin biosynthetic gene clusters and key enzyme genes related to precursor synthesis, including glucose-6-phosphate dehydrogenase, citrate synthase, and acetyl-CoA carboxylase. The obtained <i>S. gilvosporeus</i> mutant in this study can be used to develop advanced cell factories for the production of natamycin and other value-added bioproducts. | |||
TO cite this article:Wen Xiao,Liang Wang,Hongjian Zhang, et al. Improving natamycin production of <i>Streptomyces gilvosporeus</i> by ARTP mutagenesis combined with 2-deoxyglucose[OL].[ 1 March 2024] http://en.paper.edu.cn/en_releasepaper/content/4762375 |
3. High Throughput Screening of High Nisin-Producing <i>Lactococcus lactis</i> Through Heavy Ion Irradiation And EMS Compound Mutagenesis | |||
Chen Zulian,Wang Liang,Zhang Shijie,Zhang Hongjian,Chen Xusheng,Zhang Jianhua | |||
Biology 29 February 2024 | |||
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Abstract:Nisin is a natural cationic antimicrobial peptide that has been widely used in the fields of food additives, cosmetics, and medicine. Low screening efficiency is the main limiting factor for obtaining high nisin-producing <i>Lactococcus lactis</i>. Here, a high-throughput screening method was established and optimized for the rapid identification of high nisin-producing strains, based on microplate culture and microbial turbidity detection. Using this method, the nisin titer of <i>L. lactis</i> CGMCC1.2829 was rapidly improved through EMS and heavy ion irradiation compound mutagenesis. Among the 3901 mutants obtained during the two rounds of mutagenesis, <i>L. lactis</i> EZ1703 was obtained with the highest nisin titer (4035.91 IU/mL), 3.81 fold compared to the original strain. In a 1 L fermenter, the nisin titer of EZ1703 was 5726.52 IU/mL, which is 6.37 times higher than that of the original strain. Further study showed that changes in cell morphology as well as the transcriptional levels of <i>nisZ</i>, <i>nisC</i>, <i>nisI</i>, <i>nisF</i>, and <i>nisG</i> in EZ1703 are important factors for the improved nisin titer. The present study was the first to improve the nisin titer using high-throughput screening method and heavy ion irradiation technology, and the obtained L. lactis mutant can be used to develop advanced cell factories for the production of nisin. | |||
TO cite this article:Chen Zulian,Wang Liang,Zhang Shijie, et al. High Throughput Screening of High Nisin-Producing <i>Lactococcus lactis</i> Through Heavy Ion Irradiation And EMS Compound Mutagenesis[OL].[29 February 2024] http://en.paper.edu.cn/en_releasepaper/content/4762366 |
4. Production of 1,4-butanediol from succinic acid using Escherichia coli whole-cell catalysis | |||
Ping Ni,Cong Gao,Jing Wu,Wei Song,Xiaomin Li,Wanqing Wei,Xiulai Chen,Liming Liu | |||
Biology 27 February 2024 | |||
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Abstract:The microbial production of 1,4-butanediol (1,4-BDO), a crucial bulk chemical used in the organic chemical and food industries, has attracted increasing attention due to environmental concerns. However, its biosynthetic efficiency via current biotransformation routes is limited. In this study, a dual-pathway approach for 1,4-BDO production from succinic acid was developed. Specifically, a double-enzyme catalytic pathway involving carboxylic acid reductase and ethanol dehydrogenase was proposed. Optimization of the expression levels of the pathway enzymes led to a significant 318% increase in 1,4-BDO titer. Additionally, the rate-limiting enzyme MmCar was engineered to enhance substrate affinity by 50% and increase 1,4-BDO titer by 46.7%. To address cofactor supply limitations, an NADPH and ATP cycling system was established, resulting in a 48.9% increase in 1,4-BDO production. Ultimately, after 48 hours, 1,4-BDO titers reached 201 mg/L and 1555 mg/L in shake flask and 5 L fermenter, respectively. This work represents a significant advancement in 1,4-BDO synthesis from succinic acid, with potential applications in the organic chemical and food industries. | |||
TO cite this article:Ping Ni,Cong Gao,Jing Wu, et al. Production of 1,4-butanediol from succinic acid using Escherichia coli whole-cell catalysis[OL].[27 February 2024] http://en.paper.edu.cn/en_releasepaper/content/4762275 |
5. Optimization of ultrasound-mediated DNA transfer for bacteria and preservation of frozen competent cells | |||
ZHANG Meng,TANG Rongkang,LI Fangxia,JIN Wenyu,Guo Jiaxin,TENG Linzuo,MENG Guangxun,Philippe Joseph Sansonetti,GAO Yizhou | |||
Biology 27 January 2024 | |||
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Abstract:The transformation of DNA into cells is the basis of molecular biology. Common techniques include heat shock transformation, electro-transformation, conjugation, transduction, and protoplast fusion. Ultrasonic transformation technology has recently been developed to transfer DNA into competent cells. The transformation conditions, such as temperature and ultrasonic power, were studied preliminarily. However, this technique has not been widely applied because competent cells must be prepared de novo. In this study, various factors, such as ultrasonic frequency and power, were optimized for the ultrasonic transformation of Escherichia coli. The study found that the optimal conditions for ultrasonic transformation with a defined ultrasonic transformation (UT) vial were a frequency of 28 kHz and a power of 80 W. Meanwhile, this research discovered that combining the 42 C heat shock conditions with ultrasonic transformation is the most efficient method compared to using only heat shock. Additionally, the cryoprotective agents (CPAs) ratio for ultrasonic competent cells was researched and optimized. These findings provide new ideas for improving transformation efficiency and lay a foundation for expanding the application of ultrasonic transformation. | |||
TO cite this article:ZHANG Meng,TANG Rongkang,LI Fangxia, et al. Optimization of ultrasound-mediated DNA transfer for bacteria and preservation of frozen competent cells[OL].[27 January 2024] http://en.paper.edu.cn/en_releasepaper/content/4762038 |
6. The Circadian Clock in Immune Regulation | |||
JIANG Yunxin,FU Yadong,ZHAO Qihao,MA Dongcheng,LIU Chao,ZHONG Yingbin | |||
Biology 21 December 2023 | |||
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Abstract:The circadian clock is an intrinsic timekeeping mechanism enables organisms to adapt to day-night environmental changes. It regulates physiological and behavior activities in organisms in an approximate 24-hour cycle. The molecular mechanism of the circadian clock is composed of a transcriptional-translational feedback loop. Ample evidence reveals that the immune system, as an important defense mechanism of the body, is under circadian regulation. We summarize recent studies of the influence of the circadian clock on pathogen infection, the immune cells activities and immune disease. The complexs relationship between body clock, immune system, and other systems are also discussed. Finnally, we provide suggestions on the direction and importance of further research on the circadian clock and the immune system. (10 Points, Times New Roman) | |||
TO cite this article:JIANG Yunxin,FU Yadong,ZHAO Qihao, et al. The Circadian Clock in Immune Regulation[OL].[21 December 2023] http://en.paper.edu.cn/en_releasepaper/content/4761742 |
7. The structure and functions of SARS-CoV-2 nucleocapsid protein | |||
SONG Aling,GE Xingyi,QIU Ye | |||
Biology 18 April 2023 | |||
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Abstract:Severe Acute respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the third highly pathogenic human coronavirus after SARS-CoV and MERS-CoV. SARS-CoV-2 can not only cause flu-like symptoms such as cough, fever, fatigue and sore limbs, but also lead to complications such as pulmonary fibrosis, acute kidney injury and neurodegenerative diseases in partial patients. As the most abundant protein in SARS-CoV-2, N protein participates in the packaging and transcription of viral RNA, and moreover plays important roles in affecting host cell homeostasis. Previous researches demostrated that N protein triggers activation of the Smad3 signaling pathway through the p21‐ dependent G1 cell cycle arrest mechanism which leads to cell death, N protein also inhibits GSDMD-mediated pyroptosis to inhibit the release of IL-1β. N protein regulating host cell antiviral immune response through NF-κB, JAK-STAT and other signaling pathways has been revealed. In addition, studies have proven that N protein is associated with many complications, such as Parkinson\'s disease, pulmonary fibrosis and so on. In this review, we describe the known structure of SARS-CoV-2 N protein, its role in packaging viral RNA and effects on host cell homeostasis. | |||
TO cite this article:SONG Aling,GE Xingyi,QIU Ye. The structure and functions of SARS-CoV-2 nucleocapsid protein[OL].[18 April 2023] http://en.paper.edu.cn/en_releasepaper/content/4760370 |
8. Study on the renaturation process of epidermal growth factor-like protein and its therapeutic effect on neuroinflammation | |||
Yang Jingru,He Huahong,He Huafeng,Wang Huaqian | |||
Biology 25 March 2023 | |||
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Abstract:Epidermal growth factor (EGF) plays an important role in improving the inflammatory response. In this study, cholera toxin A2 subunit, cell-penetrating peptide trans-transcription activator (TAT) and EGF were fused and recombinant protein EGF-CTA2-TAT were expressed by Escherichia coli. Two methods of renaturation, affinity chromatography and dialysis, were selected to renature the protein. The renaturation efficiency of these two methods were compared. Activities of recombinant protein on promoting BALB/c 3T3 cells proliferation in vitro were also studied. After that, mice model of neuroinflammation was established by using the Lipopolysaccharide (LPS) intraperitoneal injection. The purified and renatured recombinant EGF-like protein was administered intranasally for neuroinflammation treatment. The Morris water maze (MWM) test was used to evaluate the therapeutic effects. Our results showed that recombinant EGF-like protein had a therapeutic effect on LPS-induced neuroinflammation in mice, and could remarkably improve the learning and memory ability of mice. The recombinant EGF-like protein renatured and purified by affinity chromatography in one step shows the advantages of simple process, high yield, excellent activity and low cost, providing a reference for mass production of such active proteins. | |||
TO cite this article:Yang Jingru,He Huahong,He Huafeng, et al. Study on the renaturation process of epidermal growth factor-like protein and its therapeutic effect on neuroinflammation[OL].[25 March 2023] http://en.paper.edu.cn/en_releasepaper/content/4759631 |
9. Screening of strains from reconstituted tobacco sheet making high-yield enzymes and aroma | |||
Yang Chunxue,Deng Zhang,Liao xiang ru,Guan Zhengbing | |||
Biology 01 March 2023 | |||
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Abstract:Reconstituted tobacco sheet (RTS) is critical to reduce the harm of cigarettes and considered as a comprehensive utilization approach for tobacco wastes in the tobacco industries. The aim of this study was to screen out bacteria from RTS materials capable of producing a high total amount of enzymes and aroma. A total of 21 strains with unique morphologies were obtained. Based on the results of enzymes and aroma producing capacities of the strains, one strain was screened. This strain, which was named B-NS-7, was capable of producing a total amount of 696.3 U/mL protease activity, 238.4 U/mL amylase activity, 64.3 U/mL pectinase activity and 100.0 μg/mL aroma. Combined with the results of the 16S rDNA sequencing, physiological and biochemical characteristics B-NS-7 was identified as Bacillus subtilis. Through a series of single factor experiences, the results showed that under the conditions of inoculation concentration of 1%, fermentation temperature of 37 C and time of 24 h, the highest aroma content of concentrated solutions were 116.3 μg/mL. Neophytadiene was responsible for the majority of the fragrance enhancement, and B-NS-7 was identified as an aldehydic and alkene-flavoured strain. The sensory quality of tobacco concentration solutions was superior under optimal conditions. This strain has been deposited at the China General Microbiological Culture Collection Center (CGMCC No. 23716). By way of this study, B. subtilis B-NS-7 was intended to be used in the manufacturing of RTS through microbial fermentation to improve the quality and providing suggestions for the microbial development of the RTS industry. | |||
TO cite this article:Yang Chunxue,Deng Zhang,Liao xiang ru, et al. Screening of strains from reconstituted tobacco sheet making high-yield enzymes and aroma[OL].[ 1 March 2023] http://en.paper.edu.cn/en_releasepaper/content/4759360 |
10. Personalized prognostic signature for lung cancer based on 15 transcription-related gene pairs | |||
Liao Zili,Ren Zhihao,Zhang Boxiang,Zhu Ruiyu | |||
Biology 15 February 2023 | |||
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Abstract:Lung cancer is the most aggressive malignancy and the leading cause of cancer deaths worldwide. Currently, reliable biomarkers are lacking in the diagnosis, prognosis and treatment of lung cancer. Given the significant role of transcription factors in tumorigenesis and progression, we aimed to establish a signature based on transcription-related gene pairs for the first time to predict the prognosis of lung cancer patients. The gene expression data and clinical information of 1568 lung cancer patients were obtained from The Cancer Genome Atlas data portal (TCGA) and Gene Expression Omnibus (GEO) as a training cohort and validation cohort, respectively. Through univariate Cox analysis and Least Absolute Shrinkage and Selection Operator (LASSO) analysis, we screened 15 transcription-related gene pairs to construct the transcription-related prognostic signature. Based on this signature, the samples were classified into high-risk group and low-risk group. Kaplan-Meier analysis and independent prognostic analysis showed that transcription-related prognostic signature predicted overall survival in lung cancer patients (p < 0.001). Compared with multiple clinical and pathological factors, the results of multivariate Cox regression analysis indicated that the signature was an independent prognostic factor in patients with lung cancer. Further analysis revealed the cellular pathways associated with this signature and the relationship between this signature and immune cell content. In conclusion, we established for the first time the signature of transcription-related genes on prognosis as an indicator to assess the overall survival in lung cancer patients. Our study provides new ideas for developing cancer prognostic signature and discovering new drug targets. | |||
TO cite this article:Liao Zili,Ren Zhihao,Zhang Boxiang, et al. Personalized prognostic signature for lung cancer based on 15 transcription-related gene pairs[OL].[15 February 2023] http://en.paper.edu.cn/en_releasepaper/content/4759077 |
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