76
|
Cui S, Lv X, Xu X, Chen T, Zhang H, Liu Y, Li J, Du G, Ledesma-Amaro R, Liu L. Multilayer Genetic Circuits for Dynamic Regulation of Metabolic Pathways. ACS Synth Biol 2021; 10:1587-1597. [PMID: 34213900 DOI: 10.1021/acssynbio.1c00073] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The dynamic regulation of metabolic pathways is based on changes in external signals and endogenous changes in gene expression levels and has extensive applications in the field of synthetic biology and metabolic engineering. However, achieving dynamic control is not trivial, and dynamic control is difficult to obtain using simple, single-level, control strategies because they are often affected by native regulatory networks. Therefore, synthetic biologists usually apply the concept of logic gates to build more complex and multilayer genetic circuits that can process various signals and direct the metabolic flux toward the synthesis of the molecules of interest. In this review, we first summarize the applications of dynamic regulatory systems and genetic circuits and then discuss how to design multilayer genetic circuits to achieve the optimal control of metabolic fluxes in living cells.
Collapse
|
77
|
Xu Y, Wu Y, Lv X, Sun G, Zhang H, Chen T, Du G, Li J, Liu L. Design and construction of novel biocatalyst for bioprocessing: Recent advances and future outlook. BIORESOURCE TECHNOLOGY 2021; 332:125071. [PMID: 33826982 DOI: 10.1016/j.biortech.2021.125071] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Bioprocess, a biocatalysis-based technology, is becoming popular in many research fields and widely applied in industrial manufacturing. However, low bioconversion, low productivity, and high costs during industrial processes are usually the limitation in bioprocess. Therefore, many biocatalyst strategies have been developed to meet these challenges in recent years. In this review, we firstly discuss protein engineering strategies, which are emerged for improving the biocatalysis activity of biocatalysts. Then, we summarize metabolic engineering strategies that are promoting the development of microbial cell factories. Next, we illustrate the necessity of using the combining strategy of protein engineering and metabolic engineering for efficient biocatalysts. Lastly, future perspectives about the development and application of novel biocatalyst strategies are discussed. This review provides theoretical guidance for the development of efficient, sustainable, and economical bioprocesses mediated by novel biocatalysts.
Collapse
|
78
|
Lv X, Wu Y, Gong M, Deng J, Gu Y, Liu Y, Li J, Du G, Ledesma-Amaro R, Liu L, Chen J. Synthetic biology for future food: Research progress and future directions. FUTURE FOODS 2021. [DOI: 10.1016/j.fufo.2021.100025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
|
79
|
Zhang J, Yu Y, Lin Y, Kang S, Lv X, Liu Y, Lin J, Wang J, Song C. Efficacy and safety of neoadjuvant therapy for HER2-positive early breast cancer: a network meta-analysis. Breast 2021. [DOI: 10.1016/s0960-9776(21)00167-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
80
|
Yu Y, Zhang J, Lin Y, Kang S, Lv X, Song C. Efficacy and safety of neoadjuvant therapy for Triple-Negative Breast Cancer (TNBC): a Bayesian network meta-analysis. Breast 2021. [DOI: 10.1016/s0960-9776(21)00168-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
81
|
Zhang C, Wu Y, Xu X, Lv X, Li J, Du G, Liu L. [Current status and future perspectives of metabolic network models of industrial microorganisms]. SHENG WU GONG CHENG XUE BAO = CHINESE JOURNAL OF BIOTECHNOLOGY 2021; 37:860-873. [PMID: 33783155 DOI: 10.13345/j.cjb.200640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genome-scale metabolic network model (GSMM) is an extremely important guiding tool in the targeted modification of industrial microbial strains, which helps researchers to quickly obtain industrial microbes with specific traits and has attracted increasing attention. Here we reviewe the development history of GSMM and summarized the construction method of GSMM. Furthermore, the development and application of GSMM in industrial microorganisms are elaborated by using four typical industrial microorganisms (Bacillus subtilis, Escherichia coli, Corynebacterium glutamicum, and Saccharomyces cerevisiae) as examples. In addition, prospects in the development trend of GSMM are proposed.
Collapse
|
82
|
Yuan P, Sun G, Cui S, Wu Y, Lv X, Liu Y, Li J, Du G, Liu L. Engineering a ComA Quorum-Sensing circuit to dynamically control the production of Menaquinone-4 in Bacillus subtilis. Enzyme Microb Technol 2021; 147:109782. [PMID: 33992404 DOI: 10.1016/j.enzmictec.2021.109782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 12/29/2022]
Abstract
Menaquinone-4 (MK-4) plays a significant role in bone health and cardiovascular therapy. Although many strategies have been adopted to increase the yield of MK-4 in Bacillus subtilis 168, the effectiveness of MK-4 is still low due to the inherent limitations of metabolic pathways. However, dynamic regulation based on quorum sensing (QS) has been extensively applied as a fundamental tool for fine-tuning gene expression in reaction to changes in cell density without adding expensive inducers. Nevertheless, in most reports, QS systems depend on down-regulated expression rather than up-regulated expression, which greatly limit their potential as molecular switches to control metabolic flux. To address this challenge, a modular PhrQ-RapQ-ComA QS system is developed based on promoter PA11, which is up-regulated by phosphorylated ComA (ComA-P). In this paper, firstly we analyzed the ComA-based gene expression regulation system in Bacillus subtilis 168. We constructed a promoter library of diff ;erent abilities, selected best promoters from a library, and performed mutation screening on the selected promoters. Furthermore, we constructed a PhrQ-RapQ-ComA QS system to dynamically control the synthesis of MK-4 in B. subtilis 168. Cell growth and efficient synthesis of the target product can be dynamically balanced by the QS system. Our dynamic adjustment approach increased the yield of MK-4 in shake flask from 120.1 ± 0.6 to 178.9 ± 2.8 mg/L, and reached 217 ± 4.1 mg/L in a 3-L bioreactor, which verified the effectiveness of this strategy. In summary, PhrQ-RapQ-ComA QS system can realize dynamic pathway regulation in B. subtilis 168, which can be stretched to a great deal of microorganisms to fine-tune gene expression and enhance the production of metabolites.
Collapse
|
83
|
Zheng L, Liu S, Lv X, Shi Y. Use of facial vein graft with vascularized composite auricular helical rim flap for alar rim defects. Int J Oral Maxillofac Surg 2021; 50:1435-1439. [PMID: 33678491 DOI: 10.1016/j.ijom.2021.02.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/04/2021] [Accepted: 02/12/2021] [Indexed: 11/30/2022]
Abstract
Nasal alar defects lead to facial disfigurement, and nasal ala reconstruction is an important treatment option. The vascularized composite auricular flap based on the superficial temporal artery is an ideal option for a full-thickness nasal alar defect. However, the pedicle length and the discrepancy in artery diameter between the recipient vessel and flap pedicle continue to be major problems for free auricular composite tissue transfer. Considering that the angular artery is occasionally absent and the course of the infraorbital segment of the facial vein is constant, there are often no suitable vessels around the recipient site for anastomoses to the short pedicle of the flap. In the absence of a suitable recipient artery, an infraorbital segment of the facial vein measuring 2.5cm in length was taken as a graft for the anastomosis of the superficial temporal artery and superior labial artery. End-to-end anastomosis was performed easily. The flap was inset to reconstruct the contralateral ala. The facial vein graft for anastomosis of the superficial temporal artery and branch of the facial artery is a reliable and easy method to resolve the problem of a short pedicle and large artery discrepancy for nasal ala reconstruction with a vascularized composite helical rim flap.
Collapse
|
84
|
Cheng Y, Wang T, Li R, Lv X, Yuan L, Shen J, Li Y, Yan T, Liu B, Wang L. P34.02 Detection of PD-L1 Expression and Its Clinical Significance in Circulating Tumor Cells From Patients With Non-Small-Cell Lung Cancer. J Thorac Oncol 2021. [DOI: 10.1016/j.jtho.2021.01.693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
85
|
Wen J, Shao P, Chen Y, Wang L, Lv X, Yang W, Jia Y, Jiang Z, Zhu B, Qu L. Genomic scan revealed KIT gene underlying white/gray plumage color in Chinese domestic geese. Anim Genet 2021; 52:356-360. [PMID: 33644907 DOI: 10.1111/age.13050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2021] [Indexed: 01/17/2023]
Abstract
Goose is an important type of domesticated poultry. The wild geese that are regarded as the ancestors of modern domestic geese present gray plumage. Domesticated, geese have both white and gray feathers. To elucidate the genetic mechanisms underlying the formation of white and gray plumage in geese, we resequenced the whole genome of 18 geese from six populations including white and gray goose breeds. The average sequencing depth per individual was 9.81× and the average genome coverage was 96.8%. A total of 346 genes were detected in the top 1% of FST scores of gray- and white-feathered geese, and a significant FST site was located in the intron region within the KIT gene, the 18 bp deletion in KIT having the strongest potential association with white feathers. It has been reported that a number of genes are associated with plumage colors in birds. However, no studies have identified the relationship between KIT and plumage color in birds at present, although the white coat can be attributed to mutations in KIT in some mammals. Our study showed that that KIT is a plausible candidate gene for white/gray plumage color in Chinese domestic geese.
Collapse
|
86
|
Basharat S, Huang Z, Gong M, Lv X, Ahmed A, Hussain I, Li J, Du G, Liu L. A review on current conventional and biotechnical approaches to enhance biosynthesis of steviol glycosides in Stevia rebaudiana. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.10.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
87
|
Lv X, Niu H. Mesenchymal Stem Cell Transplantation for the Treatment of Cognitive Frailty. J Nutr Health Aging 2021; 25:795-801. [PMID: 34179936 DOI: 10.1007/s12603-021-1632-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As life expectancy increases, frailty and cognitive impairment have become major factors influencing healthy aging in elderly individuals. Frailty is a complicated clinical condition characterized by decreased physiological reserve and multisystem abnormalities. Cognitive frailty is a subtype of frailty that has aroused widespread concern among the scientific community and public health organizations. We herein review the pathogenesis of cognitive frailty, such as chronic inflammatory response, immunological hypofunction, imbalanced oxidative stress, reduced regenerative function, endocrine dysfunction, and energy metabolism disorder. Although existing interventions show some therapeutic effects, they do not meet the current clinical needs. To date, studies using stem cell technology for treating age-related diseases have achieved remarkable success. This suggests the possibility of applying stem cell treatment to cognitive frailty. We analyzed stem cell-based strategies for targeting anti-inflammation, antioxidation, regeneration, and immunoregulation using mesenchymal stem cells, as well as potential therapeutic targets for cognitive frailty. Based on this investigation, we propose a highly effective and low-cost stem cell-based replacement strategy. However, there is a lack of comprehensive research on the prospect of stem cell transplantation for improving cognitive frailty. In this review, we aim to provide the scientific background and a theoretical basis for testing cell therapy in future research.
Collapse
|
88
|
Zhang S, Hu B, Liu W, Wang P, Lv X, Chen S, Shao Z. The role of structure and function changes of sensory nervous system in intervertebral disc-related low back pain. Osteoarthritis Cartilage 2021; 29:17-27. [PMID: 33007412 DOI: 10.1016/j.joca.2020.09.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 02/06/2023]
Abstract
Low back pain (LBP) is a common musculoskeletal symptom, which can be developed in multiple clinical diseases. It is widely recognized that intervertebral disc (IVD) degeneration (IVDD) is one of the leading causes of LBP. However, the pathogenesis of IVD-related LBP is still controversial, and the treatment means are also insufficient to date. In recent decades, the role of structure and function changes of sensory nervous system in the induction and the maintenance of LBP is drawing more and more attention. With the progress of IVDD, IVD cell exhaustion and extracellular matrix degradation result in IVD structural damage, while neovascularization, innervation and inflammatory activation further deteriorate the microenvironment of IVD. New nerve ingrowth into degenerated IVD amplifies the impacts of IVD-derived nociceptive molecules on sensory endings. Moreover, IVDD is usually accompanied with disc herniation, which could injure and inflame affected nerves. Under mechanical and pro-inflammatory stimulation, the pain-transmitting pathway exhibits a sensitized function state and ultimately leads to LBP. Hence, relevant pathogenic factors, such as neurotrophins, ion channels, inflammatory factors, etc., are supposed to serve as promising therapeutic targets for LBP. The purpose of this review is to comprehensively summarize the current evidence on 1) the pathological changes of sensory nervous system during IVDD and their association with LBP, and 2) potential therapeutic strategies for LBP targeting relevant pathogenic factors.
Collapse
|
89
|
Lin R, Lin S, Zhu J, Feng S, Wu Q, Fu J, Wang F, Li H, Li X, Zhang G, Yao Y, Xin M, Lai T, Lv X, Chen Y, Lin Y, Hong L, Lin S, Zhao S, Huang C. 290MO Patient controlled analgesia (PCA) versus non-pca intravenous hydromorphone for severe cancer pain: Update from a multi-center, phase III randomized trial, HMORCT09-1. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.10.283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
90
|
Gu H, Zhu T, Li X, Chen Y, Wang L, Lv X, Yang W, Jia Y, Jiang Z, Qu L. A joint analysis strategy reveals genetic changes associated with artificial selection between egg-type and meat-type ducks. Anim Genet 2020; 51:890-898. [PMID: 33058234 DOI: 10.1111/age.13014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2020] [Indexed: 12/16/2022]
Abstract
Egg-type ducks and meat-type ducks are predominantly commercial or indigenous and have been subjected to artificial directional selection. These two duck types differ substantially in body shape, production performance and reproductivity. However, the genetic changes associated with phenotypic differences remain unclear. Here, we compared the two duck types at the genomic and transcriptomic levels. We identified a large number of SNPs and genes in genomic divergent regions in terms of FST and θπ values. The corresponding genes were mainly enriched in embryonic development function and metabolic pathway. RNA-seq analysis also revealed differential gene expression in the liver and gonads. The differentially expressed genes were functionally associated with signal transmission and substance metabolism respectively. Furthermore, we found that seven genes were related to differentiation between the two types by both g genome and transcriptome analysis and were plausible candidate genes. These genes were annotated to GO categories of cell development and disease immunity. These findings will enable a better understanding of the artificial selection history of meat and egg ducks and provide a valuable resource for future research on the breeding of these two lineages.
Collapse
|
91
|
Niu T, Lv X, Liu Y, Li J, Du G, Ledesma-Amaro R, Liu L. The elucidation of phosphosugar stress response in Bacillus subtilis guides strain engineering for high N-acetylglucosamine production. Biotechnol Bioeng 2020; 118:383-396. [PMID: 32965679 DOI: 10.1002/bit.27577] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/16/2020] [Accepted: 09/20/2020] [Indexed: 12/22/2022]
Abstract
Bacillus subtilis is a preferred microbial host for the industrial production of nutraceuticals and a promising candidate for the synthesis of functional sugars, such as N-acetylglucosamine (GlcNAc). Previously, a GlcNAc-overproducer B. subtilis SFMI was constructed using glmS ribozyme dual-regulatory tool. Herein, we further engineered to enhance carbon flux from glucose towards GlcNAc synthesis. As a result, the increased flux towards GlcNAc synthesis triggered phosphosugar stress response, which caused abnormal cell growth. Unfortunately, the mechanism of phosphosugar stress response had not been elucidated in B. subtilis. To reveal the stress mechanism and overcome its negative effect in bioproduction, we performed comparative transcriptome analysis. The results indicate that cells slow glucose utilization by repression of glucose import and accelerate catabolic reactions of phosphosugar. To verify these results, we overexpressed the phosphatase YwpJ, which relieved phosphosugar stress and allowed us to identify the enzyme responsible for GlcNAc synthesis from GlcNAc 6-phosphate. In addition, the deletion of nagBB and murQ, responsible for GlcNAc precursor degradation, further improved GlcNAc synthesis. The best engineered strain, B. subtilis FMIP34, increased GlcNAc titer from 11.5 to 26.1 g/L in shake flasks and produced 87.5 g/L GlcNAc in 30-L fed-batch bioreactor. Our results not only elucidate, for the first time, the phosphosugar stress response mechanism in B. subtilis, but also demonstrate how the combination of rational metabolic engineering with novel insights into physiology and metabolism allows the construction of highly efficient microbial cell factories for the production of high-value chemicals.
Collapse
|
92
|
Sun L, Gong M, Lv X, Huang Z, Gu Y, Li J, Du G, Liu L. Current advance in biological production of short-chain organic acid. Appl Microbiol Biotechnol 2020; 104:9109-9124. [DOI: 10.1007/s00253-020-10917-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 12/31/2022]
|
93
|
Wu Y, Liu Y, Lv X, Li J, Du G, Liu L. Applications of CRISPR in a Microbial Cell Factory: From Genome Reconstruction to Metabolic Network Reprogramming. ACS Synth Biol 2020; 9:2228-2238. [PMID: 32794766 DOI: 10.1021/acssynbio.0c00349] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The well-designed microbial cell factory finds wide applications in chemical, pharmaceutical, and food industries due to its sustainable and environmentally friendly features. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) systems have been developed into powerful tools to perform genome editing and transcriptional regulation in prokaryotic and eukaryotic cells. Accordingly, these tools are useful to build microbial cell factories not only by reconstructing the genome but also by reprogramming the metabolic network. In this review, we summarize the recent significant headway and potential uses of the CRISPR technology in the construction of efficient microbial cell factories. Moreover, the future perspectives on the improvement and upgradation of CRISPR-based tools are also discussed.
Collapse
|
94
|
Wang Y, Deng X, Sun L, Lv X, Jin S, Chen X, Zhu H. 395TiP A single arm, prospective, open-label study of injected temozolomide plus hypofractionated radiation therapy for metastatic brain tumours. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
|
95
|
Liu K, Gong M, Lv X, Li J, Du G, Liu L. Biotransformation and chiral resolution of d,l-alanine into pyruvate and d-alanine with a whole-cell biocatalyst expressing l-amino acid deaminase. Biotechnol Appl Biochem 2020; 67:668-676. [PMID: 32822096 DOI: 10.1002/bab.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/14/2020] [Indexed: 01/09/2023]
Abstract
Pyruvate is an important pharmaceutical intermediate and is widely used in food, nutraceuticals, and pharmaceuticals. However, high environmental pollution caused by chemical synthesis or complex separation process of microbial fermentation methods constrain the supply of pyruvate. Here, one-step pyruvate and d-alanine production from d,l-alanine by whole-cell biocatalysis was investigated. First, l-amino acid deaminase (Pm1) from Proteus mirabilis was expressed in Escherichia coli, resulting in pyruvate titer of 12.01 g/L. Then, N-terminal coding sequences were introduced to the 5'-end of the pm1 gene to enhance the expression of Pm1 and the pyruvate titer increased to 15.13 g/L. Next, product utilization by the biocatalyst was prevented by knocking out the pyruvate uptake transporters (cstA, btsT) and the pyruvate metabolic pathway genes pps, poxB, pflB, ldhA, and aceEF using CRISPR/Cas9, yielding 30.88 g/L pyruvate titer. Finally, by optimizing the reaction conditions, the pyruvate titer was further enhanced to 43.50 g/L in 8 H with a 79.99% l-alanine conversion rate; meanwhile, the resolution of d-alanine reached 84.0%. This work developed a whole-cell biocatalyst E. coli strain for high-yield, high-efficiency, and low-pollution pyruvate and d-alanine production, which has great potential for the commercial application in the future.
Collapse
|
96
|
Deng J, Lv X, Li J, Du G, Chen J, Liu L. Recent advances and challenges in microbial production of human milk oligosaccharides. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s43393-020-00004-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
97
|
Wang N, Guan F, Lv X, Han D, Zhang Y, Wu N, Xia X, Tian J. Enhancing secretion of polyethylene terephthalate hydrolase PETase in
Bacillus subtilis
WB600 mediated by the SP
amy
signal peptide. Lett Appl Microbiol 2020; 71:235-241. [DOI: 10.1111/lam.13312] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/28/2020] [Accepted: 05/04/2020] [Indexed: 11/29/2022]
|
98
|
Chen T, Xia H, Cui S, Lv X, Li X, Liu Y, Li J, Du G, Liu L. Combinatorial Methylerythritol Phosphate Pathway Engineering and Process Optimization for Increased Menaquinone-7 Synthesis in Bacillus subtilis. J Microbiol Biotechnol 2020; 30:762-769. [PMID: 32482943 PMCID: PMC9745656 DOI: 10.4014/jmb.1912.12008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/17/2020] [Indexed: 12/15/2022]
Abstract
Vitamin K2 (menaquinone) is an essential vitamin existing in the daily diet, and menaquinone-7 (MK-7) is an important form of it. In a recent work, we engineered the synthesis modules of MK-7 in Bacillus subtilis, and the strain BS20 could produce 360 mg/l MK-7 in shake flasks, while the methylerythritol phosphate (MEP) pathway, which provides the precursor isopentenyl diphosphate for MK-7 synthesis, was not engineered. In this study, we overexpressed five genes of the MEP pathway in BS20 and finally obtained a strain (BS20DFHG) with MK-7 titer of 415 mg/l in shake flasks. Next, we optimized the fermentation process parameters (initial pH, temperature and aeration) in an 8-unit parallel bioreactor system consisting of 300-ml glass vessels. Based on this, we scaled up the MK-7 production by the strain BS20DFHG in a 50-l bioreactor, and the highest MK-7 titer reached 242 mg/l. Here, we show that the engineered strain BS20DFHG may be used for the industrial production of MK-7 in the future.
Collapse
|
99
|
Lv X, Wu Y, Tian R, Gu Y, Liu Y, Li J, Du G, Ledesma-Amaro R, Liu L. Synthetic metabolic channel by functional membrane microdomains for compartmentalized flux control. Metab Eng 2020; 59:106-118. [DOI: 10.1016/j.ymben.2020.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 10/24/2022]
|
100
|
Shi L, Liu L, Lv X, Ma Z, Li C, Li Y, Zhao F, Sun D, Han B. Identification of genetic effects and potential causal polymorphisms of CPM gene impacting milk fatty acid traits in Chinese Holstein. Anim Genet 2020; 51:491-501. [PMID: 32301146 DOI: 10.1111/age.12936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 02/03/2020] [Accepted: 03/15/2020] [Indexed: 11/27/2022]
Abstract
Our previous GWAS revealed 83 significant SNPs and 20 promising candidate genes associated with milk fatty acid traits in dairy cattle. Out of them, the carboxypeptidase M (CPM) gene contains a genome-wide significant SNP, Hapmap49848-BTA-106779, which is strongly associated with myristic acid (C14:0; P = 0.0064). Herein, we aimed to confirm the genetic effects of CPM on milk fatty acids in Chinese Holstein. Seven SNPs were detected by re-sequencing the sequences of entire exons and 3000 bp of up-/downstream flanking regions of the CPM gene, of which three were in 5' flanking region, one in the 3' UTR and three were in the 3' flanking region. Using the Haploview 4.1, we estimated the LD among the identified SNPs and found two haplotype blocks. With the animal model, we performed the SNP- and haplotype-based association analyses, and observed that these SNPs and haplotype blocks mainly had strong genetic associations with medium-chain saturated fatty acids (caproic acid, C6:0; caprylic acid, C8:0; capric acid, C10:0; and lauric acid, C12:0) (P < 0.0001-0.0257). In addition, using the Genomatix software, we predicted that three SNPs in the 5' flanking region of CPM (g.45079507A>G, g.45080228C>A and g.45080335C>G) changed the transcription factor binding sites for PREF (progesterone receptor biding site), ZBRK1 (transcription factor with eight central zinc fingers and an N-terminal KRAB domain), SOX9 (sex-determining region Y-box 9, dimeric binding sites), SOX6 (sex-determining region Y-box 6) and FOXP1-ES (alternative splicing variant of FOXP1, activated in ESCs). Further, the dual-luciferase reporter assay showed these three SNPs altered the transcriptional activity of CPM gene (P ≤ 0.0006). In summary, using the post-GWAS strategy, we first confirmed the significant genetic effects of CPM with milk fatty acids in dairy cattle, and identified three potential causal mutations.
Collapse
|