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Moody S, Bull J, Dudley E, Loveridge E. The impact of combinatorial stress on the growth dynamics and metabolome of
Burkholderia mesoacidophila
demonstrates the complexity of tolerance mechanisms. J Appl Microbiol 2019; 127:1521-1531. [DOI: 10.1111/jam.14404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/15/2022]
Affiliation(s)
- S.C. Moody
- College of Science Swansea University Swansea UK
- School of Sport, Health and Social Sciences Solent University Southampton UK
| | - J.C. Bull
- College of Science Swansea University Swansea UK
| | - E. Dudley
- College of Medicine Swansea University Swansea UK
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Han PP, Shen SG, Guo RJ, Zhao DX, Lin YH, Jia SR, Yan RR, Wu YK. ROS Is a Factor Regulating the Increased Polysaccharide Production by Light Quality in the Edible Cyanobacterium Nostoc flagelliforme. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:2235-2244. [PMID: 30724068 DOI: 10.1021/acs.jafc.8b06176] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To explore the regulatory factor of light quality affecting exopolysaccharide (EPS) production, transcriptome analysis of Nostoc flagelliforme cells exposed to red light (R), blue light (B), and mixed light (B/R = 15:7) (BR) with white fluorescent light as control was performed. The differentially expressed genes mainly enriched in carbohydrate metabolism and energy metabolism. Significant enrichment in the oxidation-reduction process and energy metabolism indicated that intracellular redox homeostasis was disrupted. An assay of reactive oxygen species (ROS) and malondialdehyde contents demonstrated light quality induced oxidative stress. To illustrate the relationship between ROS level and EPS accumulation, the effects of the exogenous addition of ROS scavenger N-acetyl cysteine and inducer H2O2 on the oxidation-reduction level and EPS production were compared. The results revealed that light quality regulated EPS biosynthesis via the intracellular ROS level directly other than oxidative stress. Understanding such relationships might provide guidance for efficient EPS production to regulate the intracellular redox level.
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Affiliation(s)
- Pei-Pei Han
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Shi-Gang Shen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Rong-Jun Guo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Dong-Xue Zhao
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Ya-Hui Lin
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Shi-Ru Jia
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Rong-Rong Yan
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
| | - Yi-Kai Wu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, State Key Laboratory of Food Nutrition and Safety, College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , P.R. China
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Zou W, Xiong X, Zhang J, Zhang K, Zhao X, Zhao C. Reconstruction and analysis of a genome-scale metabolic model of Methylovorus sp. MP688, a high-level pyrroloquinolone quinone producer. Biosystems 2018; 172:37-42. [PMID: 30125625 DOI: 10.1016/j.biosystems.2018.07.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 04/27/2018] [Accepted: 07/18/2018] [Indexed: 01/25/2023]
Abstract
Methylovorus sp. MP688 is a methylotrophic bacterium that can be used as a pyrroloquinolone quinone (PQQ) producer. To obtain a comprehensive understanding of its metabolic capabilities, we constructed a genome-scale metabolic model (iWZ583) of Methylovorus sp. MP688, based on its genome annotations, data from public metabolic databases, and literature mining. The model includes 772 reactions, 764 metabolites, and 583 genes. Growth of Methylovorus sp. MP688 was simulated using different carbon and nitrogen sources, and the results were consistent with experimental data. A core metabolic essential gene set of 218 genes was predicted by gene essentiality analysis on minimal medium containing methanol. Based on in silico predictions, the addition of aspartate to the medium increased PQQ production by 4.6- fold. Deletion of three reactions associated with four genes (MPQ_1150, MPQ_1560, MPQ_1561, MPQ_1562) was predicted to yield a PQQ production rate of 0.123 mmol/gDW/h, while cell growth decreased by 2.5%. Here, model iWZ583 represents a useful platform for understanding the phenotype of Methylovorus sp. MP688 and improving PQQ production.
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Affiliation(s)
- Wei Zou
- College of Bioengineering, Sichuan University of Science & Engineering, 180 Xueyuan Road, Zigong, Sichuan 643000, China.
| | - Xianghua Xiong
- Laboratory of Microorganism Engineering, Beijing Institute of Biotechnology, 20 Dongdajie, Fengtai, Beijing 100071, China
| | - Jing Zhang
- College of Bioengineering, Sichuan University of Science & Engineering, 180 Xueyuan Road, Zigong, Sichuan 643000, China
| | - Kaizheng Zhang
- College of Bioengineering, Sichuan University of Science & Engineering, 180 Xueyuan Road, Zigong, Sichuan 643000, China
| | - Xingxiu Zhao
- College of Bioengineering, Sichuan University of Science & Engineering, 180 Xueyuan Road, Zigong, Sichuan 643000, China
| | - Changqing Zhao
- College of Bioengineering, Sichuan University of Science & Engineering, 180 Xueyuan Road, Zigong, Sichuan 643000, China
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Contribution of YthA, a PspC Family Transcriptional Regulator of Lactococcus lactis F44 Acid Tolerance and Nisin Yield: a Transcriptomic Approach. Appl Environ Microbiol 2018. [PMID: 29305506 DOI: 10.1128/aem.02483-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
To overcome the adverse impacts of environmental stresses during growth, different adaptive regulation mechanisms can be activated in Lactococcus lactis In this study, the transcription levels of eight transcriptional regulators of L. lactis subsp. lactis F44 under acid stress were analyzed using quantitative reverse transcription-PCR. Eight gene-overexpressing strains were then constructed to examine their influences on acid-resistant capability. Overexpressing ythA, a PspC family transcriptional regulator, increased the survival rate by 3.2-fold compared to the control at the lethal pH 3.0 acid shock. Moreover, the nisin yield was increased by 45.50%. The ythA-overexpressing strain FythA appeared to have higher intracellular pH stability and nisin-resistant ability. Subsequently, transcriptome analysis revealed that the vast majority of genes associated with amino acid biosynthesis, including arginine, serine, phenylalanine, and tyrosine, were predominantly upregulated in FythA. Arginine biosynthesis (argG and argH), arginine deiminase pathway, and polar amino acid transport (ysfE and ysfF) were proposed to be the main regulation mechanisms of YthA. Furthermore, the transcription of genes associated with pyrimidine and exopolysaccharide biosynthesis were upregulated. The transcriptional levels of nisIPRKFEG genes were substantially higher in FythA, which directly contributed to the yield and resistance of nisin. Three potential DNA-binding sequences were predicted by computer analysis using the upstream regions of genes with prominent changes. This study showed that YthA could increase acid resistance and nisin yield and revealed a putative regulation mechanism of YthA.IMPORTANCE Nisin, produced by Lactococcus lactis subsp. lactis, is widely used as a safe food preservative. Acid stress becomes the primary restrictive factor of cell growth and nisin yield. In this research, we found that the transcriptional regulator YthA was conducive to enhancing the acid resistance of L. lactis F44. Overexpressing ythA could significantly improve the survival rate and nisin yield. The stability of intracellular pH and nisin resistance were also increased. Transcriptome analysis showed that nisin immunity and the biosynthesis of some amino acids, pyrimidine, and exopolysaccharides were enhanced in the engineered strain. This study elucidates the regulation mechanism of YthA and provides a novel strategy for constructing robust industrial L. lactis strains.
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Contribution of YthA, a PspC Family Transcriptional Regulator of Lactococcus lactis F44 Acid Tolerance and Nisin Yield: a Transcriptomic Approach. Appl Environ Microbiol 2018; 84:AEM.02483-17. [PMID: 29305506 DOI: 10.1128/aem.02483-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/22/2017] [Indexed: 11/20/2022] Open
Abstract
To overcome the adverse impacts of environmental stresses during growth, different adaptive regulation mechanisms can be activated in Lactococcus lactis In this study, the transcription levels of eight transcriptional regulators of L. lactis subsp. lactis F44 under acid stress were analyzed using quantitative reverse transcription-PCR. Eight gene-overexpressing strains were then constructed to examine their influences on acid-resistant capability. Overexpressing ythA, a PspC family transcriptional regulator, increased the survival rate by 3.2-fold compared to the control at the lethal pH 3.0 acid shock. Moreover, the nisin yield was increased by 45.50%. The ythA-overexpressing strain FythA appeared to have higher intracellular pH stability and nisin-resistant ability. Subsequently, transcriptome analysis revealed that the vast majority of genes associated with amino acid biosynthesis, including arginine, serine, phenylalanine, and tyrosine, were predominantly upregulated in FythA. Arginine biosynthesis (argG and argH), arginine deiminase pathway, and polar amino acid transport (ysfE and ysfF) were proposed to be the main regulation mechanisms of YthA. Furthermore, the transcription of genes associated with pyrimidine and exopolysaccharide biosynthesis were upregulated. The transcriptional levels of nisIPRKFEG genes were substantially higher in FythA, which directly contributed to the yield and resistance of nisin. Three potential DNA-binding sequences were predicted by computer analysis using the upstream regions of genes with prominent changes. This study showed that YthA could increase acid resistance and nisin yield and revealed a putative regulation mechanism of YthA.IMPORTANCE Nisin, produced by Lactococcus lactis subsp. lactis, is widely used as a safe food preservative. Acid stress becomes the primary restrictive factor of cell growth and nisin yield. In this research, we found that the transcriptional regulator YthA was conducive to enhancing the acid resistance of L. lactis F44. Overexpressing ythA could significantly improve the survival rate and nisin yield. The stability of intracellular pH and nisin resistance were also increased. Transcriptome analysis showed that nisin immunity and the biosynthesis of some amino acids, pyrimidine, and exopolysaccharides were enhanced in the engineered strain. This study elucidates the regulation mechanism of YthA and provides a novel strategy for constructing robust industrial L. lactis strains.
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Liu F, Liu W, Tian S. Artificial neural network optimization of Althaea rosea seeds polysaccharides and its antioxidant activity. Int J Biol Macromol 2014; 70:100-7. [PMID: 24984022 DOI: 10.1016/j.ijbiomac.2014.06.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 06/01/2014] [Accepted: 06/14/2014] [Indexed: 01/27/2023]
Abstract
A combination of an orthogonal L16(4)4 test design and a three-layer artificial neural network (ANN) model was applied to optimize polysaccharides from Althaea rosea seeds extracted by hot water method. The highest optimal experimental yield of A. rosea seed polysaccharides (ARSPs) of 59.85 mg/g was obtained using three extraction numbers, 113 min extraction time, 60.0% ethanol concentration, and 1:41 solid-liquid ratio. Under these optimized conditions, the ARSP experimental yield was very close to the predicted yield of 60.07 mg/g and was higher than the orthogonal test results (40.86 mg/g). Structural characterizations were conducted using physicochemical property and FTIR analysis. In addition, the study of ARSP antioxidant activity demonstrated that polysaccharides exhibited high superoxide dismutase activity, strong reducing power, and positive scavenging activity on superoxide anion, hydroxyl radical, 2,2-diphenyl-1-picrylhydrazyl, and reducing power. Our results indicated that ANNs were efficient quantitative tools for predicting the total ARSP content.
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Affiliation(s)
- Feng Liu
- College of Chemistry and Chemical Engineering, Xinjiang Normal University, Xinjiang 830054, China
| | - Wenhui Liu
- College of Information Sciences and Technology, Xinjiang Education Institute, Xinjiang 830043, China
| | - Shuge Tian
- Central Laboratory of Xinjiang Medical University, Xinjiang 830011, China.
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