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Balcha ES, Macey MC, Gemeda MT, Cavalazzi B, Woldesemayat AA. Mining the microbiome of Lake Afdera to gain insights into microbial diversity and biosynthetic potential. FEMS MICROBES 2024; 5:xtae008. [PMID: 38560625 PMCID: PMC10979467 DOI: 10.1093/femsmc/xtae008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 01/24/2024] [Accepted: 03/05/2024] [Indexed: 04/04/2024] Open
Abstract
Microorganisms inhabiting hypersaline environments have received significant attention due to their ability to thrive under poly-extreme conditions, including high salinity, elevated temperatures and heavy metal stress. They are believed to possess biosynthetic gene clusters (BGCs) that encode secondary metabolites as survival strategy and offer potential biotechnological applications. In this study, we mined BGCs in shotgun metagenomic sequences generated from Lake Afdera, a hypersaline lake in the Afar Depression, Ethiopia. The microbiome of Lake Afdera is predominantly bacterial, with Acinetobacter (18.6%) and Pseudomonas (11.8%) being ubiquitously detected. A total of 94 distinct BGCs were identified in the metagenomic data. These BGCs are found to encode secondary metabolites with two main categories of functions: (i) potential pharmaceutical applications (nonribosomal peptide synthase NRPs, polyketide synthase, others) and (ii) miscellaneous roles conferring adaptation to extreme environment (bacteriocins, ectoine, others). Notably, NRPs (20.6%) and bacteriocins (10.6%) were the most abundant. Furthermore, our metagenomic analysis predicted gene clusters that enable microbes to defend against a wide range of toxic metals, oxidative stress and osmotic stress. These findings suggest that Lake Afdera is a rich biological reservoir, with the predicted BGCs playing critical role in the survival and adaptation of extremophiles.
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Affiliation(s)
- Ermias Sissay Balcha
- School of Medical Laboratory Science, College of Health Sciences, Hawassa University, 16417, Hawassa, Ethiopia
- Biotechnology and Bioprocess Center of Excellence, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia
| | - Michael C Macey
- Astrobiology OU, School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom
| | - Mesfin Tafesse Gemeda
- Biotechnology and Bioprocess Center of Excellence, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia
| | - Barbara Cavalazzi
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - Adugna Abdi Woldesemayat
- Biotechnology and Bioprocess Center of Excellence, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia
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2
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Son Y, Min J, Shin Y, Park W. Morphological and physiological adaptations of psychrophilic Pseudarthrobacter psychrotolerans YJ56 under temperature stress. Sci Rep 2023; 13:14970. [PMID: 37697016 PMCID: PMC10495460 DOI: 10.1038/s41598-023-42179-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/06/2023] [Indexed: 09/13/2023] Open
Abstract
Both culture-independent and culture-dependent analyses using Nanopore-based 16S rRNA sequencing showed that short-term exposure of Antarctic soils to low temperature increased biomass with lower bacterial diversity and maintained high numbers of the phylum Proteobacteria, Firmicute, and Actinobacteria including Pseudarthrobacter species. The psychrophilic Pseudarthrobacter psychrotolerans YJ56 had superior growth at 13 °C, but could not grow at 30 °C, compared to other bacteria isolated from the same Antarctic soil. Unlike a single rod-shaped cell at 13 °C, strain YJ56 at 25 °C was morphologically shifted into a filamentous bacterium with several branches. Comparative genomics of strain YJ56 with other genera in the phylum Actinobacteria indicate remarkable copy numbers of rimJ genes that are possibly involved in dual functions, acetylation of ribosomal proteins, and stabilization of ribosomes by direct binding. Our proteomic data suggested that Actinobacteria cells experienced physiological stresses at 25 °C, showing the upregulation of chaperone proteins, GroEL and catalase, KatE. Level of proteins involved in the assembly of 50S ribosomal proteins and L29 in 50S ribosomal proteins increased at 13 °C, which suggested distinct roles of many ribosomal proteins under different conditions. Taken together, our data highlights the cellular filamentation and protein homeostasis of a psychrophilic YJ56 strain in coping with high-temperature stress.
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Affiliation(s)
- Yongjun Son
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Jihyeon Min
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Yoonjae Shin
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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3
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Zhang H, Chen C, Yang Z, Ye L, Miao J, Lan Y, Wang Q, Ye Z, Cao Y, Liu G. Combined transcriptomic and proteomic analysis of the antibacterial mechanisms of an antimicrobial substance produced by Lactobacillus paracasei FX-6 against colistin-resistant Escherichia coli. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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4
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Efficient degradation of hydroquinone by a metabolically engineered Pseudarthrobacter sulfonivorans strain. Arch Microbiol 2022; 204:588. [PMID: 36048304 DOI: 10.1007/s00203-022-03214-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/02/2022]
Abstract
Pseudarthrobacter sulfonivorans strain Ar51 can degrade crude oil and multi-substituted benzene compounds efficiently at low temperatures. However, it cannot degrade hydroquinone, which is a key intermediate in the degradation of several other compounds of environmental importance, such as 4-nitrophenol, g-hexachlorocyclohexane, 4-hydroxyacetophenone and 4-aminophenol. Here we co-expressed the two subunits of hydroquinone dioxygenase from Sphingomonas sp. strain TTNP3 with different promoters in the strain Ar51. The strain with 2 hdnO promoters exhibited the strongest hydroquinone catabolic activity. However, in the absence of antibiotic selection this ability to degrade hydroquinone was lost due to plasmid instability. Consequently, we constructed a hisD knockout strain, which was unable to synthesise histidine. By introducing the hisD gene onto the plasmid, the ability to degrade hydroquinone in the absence of antibiotic selection was stabilised. In addition, to make the strain more stable for industrial applications, we knocked out the recA gene and integrated the hydroquinone dioxygenase genes at this chromosomal locus. This strain exhibited the strongest activity in catabolizing hydroquinone, up to 470 mg/L in 16 h without antibiotic selection. In addition, this activity was shown to be stable when the strain has cultured in medium without antibiotic selection after 20 passages.
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5
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Liu X, Wang Z, Xiao J, Zhou X, Xu Y. Osmotic stress tolerance and transcriptome analysis of Gluconobacter oxydans to extra-high titers of glucose. Front Microbiol 2022; 13:977024. [PMID: 36033857 PMCID: PMC9412170 DOI: 10.3389/fmicb.2022.977024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
Gluconobacter oxydans has been widely acknowledged as an ideal strain for industrial bio-oxidations with fantastic yield and productivity. Even 600 g/L xylose can be catalyzed efficiently in a sealed and compressed oxygen-supplying bioreactor. Therefore, the present study seeks to explore the osmotic stress tolerance against extra-high titer of representative lignocellulosic sugars like glucose. Gluconobacter oxydans can well adapted and fermented with initial 600 g/L glucose, exhibiting the highest bio-tolerance in prokaryotic strains and the comparability to the eukaryotic strain of Saccharomyces cerevisiae. 1,432 differentially expressed genes corresponding to osmotic pressure are detected through transcriptome analysis, involving several genes related to the probable compatible solutes (trehalose and arginine). Gluconobacter oxydans obtains more energy by enhancing the substrate-level phosphorylation, resulting in the increased glucose consumption rate after fermentation adaption phase. This study will provide insights into further investigation of biological tolerance and response to extra-high titers of glucose of G. oxydans.
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Affiliation(s)
- Xinlu Liu
- Key Laboratory of Forestry Genetics and Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing, China
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
- Jiangsu Province Key Laboratory of Green Biomass-based Fuels and Chemicals, Nanjing, China
| | - Zhiwei Wang
- Key Laboratory of Forestry Genetics and Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing, China
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
- Jiangsu Province Key Laboratory of Green Biomass-based Fuels and Chemicals, Nanjing, China
| | - Jianjian Xiao
- Key Laboratory of Forestry Genetics and Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing, China
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
- Jiangsu Province Key Laboratory of Green Biomass-based Fuels and Chemicals, Nanjing, China
| | - Xin Zhou
- Key Laboratory of Forestry Genetics and Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing, China
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
- Jiangsu Province Key Laboratory of Green Biomass-based Fuels and Chemicals, Nanjing, China
| | - Yong Xu
- Key Laboratory of Forestry Genetics and Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing, China
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
- Jiangsu Province Key Laboratory of Green Biomass-based Fuels and Chemicals, Nanjing, China
- *Correspondence: Yong Xu,
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6
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Hartmann FSF, Udugama IA, Seibold GM, Sugiyama H, Gernaey KV. Digital models in biotechnology: Towards multi-scale integration and implementation. Biotechnol Adv 2022; 60:108015. [PMID: 35781047 DOI: 10.1016/j.biotechadv.2022.108015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/03/2022] [Accepted: 06/27/2022] [Indexed: 12/28/2022]
Abstract
Industrial biotechnology encompasses a large area of multi-scale and multi-disciplinary research activities. With the recent megatrend of digitalization sweeping across all industries, there is an increased focus in the biotechnology industry on developing, integrating and applying digital models to improve all aspects of industrial biotechnology. Given the rapid development of this field, we systematically classify the state-of-art modelling concepts applied at different scales in industrial biotechnology and critically discuss their current usage, advantages and limitations. Further, we critically analyzed current strategies to couple cell models with computational fluid dynamics to study the performance of industrial microorganisms in large-scale bioprocesses, which is of crucial importance for the bio-based production industries. One of the most challenging aspects in this context is gathering intracellular data under industrially relevant conditions. Towards comprehensive models, we discuss how different scale-down concepts combined with appropriate analytical tools can capture intracellular states of single cells. We finally illustrated how the efforts could be used to develop digitals models suitable for both cell factory design and process optimization at industrial scales in the future.
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Affiliation(s)
- Fabian S F Hartmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Isuru A Udugama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan; Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
| | - Gerd M Seibold
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Hirokazu Sugiyama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan
| | - Krist V Gernaey
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
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7
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Li J, Yang X, Lai JL, Zhang Y, Luo XG, Zhao SP, Zhu YB. Characteristics of RDX degradation and the mechanism of the RDX exposure response in a Klebsiella sp. strain. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Jiang ZM, Zhang BH, Sun HM, Zhang T, Yu LY, Zhang YQ. Properties of Modestobacter deserti sp. nov., a Kind of Novel Phosphate-Solubilizing Actinobacteria Inhabited in the Desert Biological Soil Crusts. Front Microbiol 2021; 12:742798. [PMID: 34803963 PMCID: PMC8602919 DOI: 10.3389/fmicb.2021.742798] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
Three Gram-stain-positive, aerobic, motile actinobacterial strains designated as CPCC 205119T, CPCC 205215, and CPCC 205251 were isolated from different biological soil crust samples collected from Tengger Desert, China. The 16S rRNA gene sequence comparison of these three strains showed they had almost identical 16S rRNA genes, which were closely related to members of the family Geodermatophilaceae, with the highest similarities of 96.3–97.3% to the species of Modestobacter. In the phylogenetic tree based on 16S rRNA gene sequences, these isolates clustered into a subclade next to the branch containing the species of Modestobacter lapidis and Modestobacter multiseptatus, within the lineage of the genus Modestobacter. The comparative genomic characteristics (values of ANI, dDDH, AAI, and POCP) and the phenotypic properties (morphological, physiological, and chemotaxonomic characteristics) of these isolates readily supported to affiliate them to the genus Modestobacter as a single separate species. For which, we proposed that the isolates CPCC 205119T, CPCC 205215, and CPCC 205251 represent a novel species of the genus Modestobacter as Modestobacter deserti sp. nov. CPCC 205119T (=I12A-02624=NBRC 113528T=KCTC 49201T) is the type strain. The genome of strain CPCC 205119T consisted of one chromosome (4,843,235bp) containing 4,424 coding genes, 48 tRNA genes, five rRNA genes, three other ncRNA genes, and 101 pseudogenes, with G+C content of 74.7%. The whole-genome sequences analysis indicated that this species contained alkaline phosphatase genes (phoA/phoD), phosphate transport-related genes (phoU, phnC, phnD, phnE, phoB, phoH, phoP, phoR, pitH, ppk, pstA, pstB, pstC, and pstS), trehalose-phosphate synthase gene (otsA), trehalose 6-phosphate phosphatase gene (otsB) and other encoding genes for the properties that help the microorganisms to adapt to harsh environmental conditions prevalent in deserts. Strains of this species could solubilize tricalcium phosphate [Ca3(PO4)2] and phytin, assimilate pyrophosphate, thiophosphate, dithiophosphate, phosphoenol pyruvate, 2-deoxy-d-glucose-6-phosphate, and cysteamine-S-phosphate.
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Affiliation(s)
- Zhu-Ming Jiang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Bing-Huo Zhang
- College of Life Science, Jiujiang University, Jiujiang, China
| | - Hong-Min Sun
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Tao Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Li-Yan Yu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yu-Qin Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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9
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Mycobacterial OtsA Structures Unveil Substrate Preference Mechanism and Allosteric Regulation by 2-Oxoglutarate and 2-Phosphoglycerate. mBio 2019; 10:mBio.02272-19. [PMID: 31772052 PMCID: PMC6879718 DOI: 10.1128/mbio.02272-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mycobacterial infections are a significant source of mortality worldwide, causing millions of deaths annually. Trehalose is a multipurpose disaccharide that plays a fundamental structural role in these organisms as a component of mycolic acids, a molecular hallmark of the cell envelope of mycobacteria. Here, we describe the first mycobacterial OtsA structures. We show mechanisms of substrate preference and show that OtsA is regulated allosterically by 2-oxoglutarate and 2-phosphoglycerate at an interfacial site. These results identify a new allosteric site and provide insight on the regulation of trehalose synthesis through the OtsAB pathway in mycobacteria. Trehalose is an essential disaccharide for mycobacteria and a key constituent of several cell wall glycolipids with fundamental roles in pathogenesis. Mycobacteria possess two pathways for trehalose biosynthesis. However, only the OtsAB pathway was found to be essential in Mycobacterium tuberculosis, with marked growth and virulence defects of OtsA mutants and strict essentiality of OtsB2. Here, we report the first mycobacterial OtsA structures from Mycobacterium thermoresistibile in both apo and ligand-bound forms. Structural information reveals three key residues in the mechanism of substrate preference that were further confirmed by site-directed mutagenesis. Additionally, we identify 2-oxoglutarate and 2-phosphoglycerate as allosteric regulators of OtsA. The structural analysis in this work strongly contributed to define the mechanisms for feedback inhibition, show different conformational states of the enzyme, and map a new allosteric site.
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10
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Solhaug EM, Johnson E, Carter CJ. Carbohydrate Metabolism and Signaling in Squash Nectaries and Nectar Throughout Floral Maturation. PLANT PHYSIOLOGY 2019; 180:1930-1946. [PMID: 31213512 PMCID: PMC6670107 DOI: 10.1104/pp.19.00470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/05/2019] [Indexed: 05/09/2023]
Abstract
Floral nectar is a sugary solution produced by plants to entice pollinator visitation. A general mechanism for nectar secretion has been established from genetic studies in Arabidopsis (Arabidopsis thaliana); however, supporting metabolic and biochemical evidence for this model is scarce in other plant species. We used squash (Cucurbita pepo) to test whether the genetic model of nectar secretion in Arabidopsis is supported at the metabolic level in other species. As such, we analyzed the expression and activity of key enzymes involved in carbohydrate metabolism in squash nectaries throughout floral maturation and the associated starch and soluble sugars, as well as nectar volume and sugar under different growth conditions. Here we show that the steps that are important for nectar secretion in Arabidopsis, including nectary starch degradation, Suc synthesis, and Suc export, are supported by metabolic and biochemical data in C. pepo Additionally, our findings suggest that sugars imported from the phloem during nectar secretion, without prior storage as starch, are important for generating C. pepo nectar. Finally, we predict that trehalose and trehalose 6-P play important regulatory roles in nectary starch degradation and nectar secretion. These data improve our understanding of how nectar is produced in an agronomically relevant species with the potential for use as a model to help us gain insight into the biochemistry and metabolism of nectar secretion in flowering plants.
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Affiliation(s)
- Erik M Solhaug
- Department of Plant & Microbial Biology, University of Minnesota, St. Paul, Minnesota
| | - Elizabeth Johnson
- Department of Plant & Microbial Biology, University of Minnesota, St. Paul, Minnesota
| | - Clay J Carter
- Department of Plant & Microbial Biology, University of Minnesota, St. Paul, Minnesota
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11
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Lu X, Chen Q, Cui X, Abozeid A, Liu Y, Liu J, Tang Z. Comparative metabolomics of two saline-alkali tolerant plants Suaeda glauca and Puccinellia tenuiflora based on GC-MS platform. Nat Prod Res 2019; 35:499-502. [PMID: 31282217 DOI: 10.1080/14786419.2019.1633647] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Suaeda glauca and Puccinellia tenuiflora are two important saline-alkali tolerant plants that can improve the soil properties. For exploring the different tolerance mechanisms between them, GC-MS-based metabolomics was used to comprehensively evaluate the primary metabolites differences, a total of 51 different metabolites were present in different quantities. The identified compounds were mainly 11 sugars, 7 amino acids, 5 alcohols and 18 organic acids; they play an important role in responding to the saline-alkali stress and distinguish between S. glauca and P. tenuiflora. All identified metabolites classes showed similar trend to largely accumulate in P. tenuiflora roots and S. glauca shoots, this reveals that the two plants used different physiological strategies to cope with saline-alkali stress.
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Affiliation(s)
- Xueyan Lu
- Center for Ecological Research, Northeast Forestry University, Harbin, China.,Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China
| | - Qi Chen
- Center for Ecological Research, Northeast Forestry University, Harbin, China.,Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China
| | - Xiaoyang Cui
- Center for Ecological Research, Northeast Forestry University, Harbin, China
| | - Ann Abozeid
- Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China.,Botany Department, Faculty of Science, Menoufia University, Shebin El-koom, Egypt
| | - Yang Liu
- Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China
| | - Jia Liu
- Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China
| | - Zhonghua Tang
- Key Laboratory of Plant Ecology, Northeast Forestry University, Harbin, China
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12
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Wang X, Li Q, Sun C, Cai Z, Zheng X, Guo X, Ni X, Zhou W, Guo Y, Zheng P, Chen N, Sun J, Li Y, Ma Y. GREACE-assisted adaptive laboratory evolution in endpoint fermentation broth enhances lysine production by Escherichia coli. Microb Cell Fact 2019; 18:106. [PMID: 31186003 PMCID: PMC6560909 DOI: 10.1186/s12934-019-1153-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 06/01/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Late-stage fermentation broth contains high concentrations of target chemicals. Additionally, it contains various cellular metabolites which have leaked from lysed cells, which would exert multifactorial stress to industrial hyperproducers and perturb both cellular metabolism and product formation. Although adaptive laboratory evolution (ALE) has been wildly used to improve stress tolerance of microbial cell factories, single-factor stress condition (i.e. target product or sodium chloride at a high concentration) is currently provided. In order to enhance bacterial stress tolerance to actual industrial production conditions, ALE in late-stage fermentation broth is desired. Genome replication engineering assisted continuous evolution (GREACE) employs mutants of the proofreading element of DNA polymerase complex (DnaQ) to facilitate mutagenesis. Application of GREACE coupled-with selection under stress conditions is expected to accelerate the ALE process. RESULTS In this study, GREACE was first modified by expressing a DnaQ mutant KR5-2 using an arabinose inducible promoter on a temperature-sensitive plasmid, which resulted in timed mutagenesis introduction. Using this method, tolerance of a lysine hyperproducer E. coli MU-1 was improved by enriching mutants in a lysine endpoint fermentation broth. Afterwards, the KR5-2 expressing plasmid was cured to stabilize acquired genotypes. By subsequent fermentation evaluation, a mutant RS3 with significantly improved lysine production capacity was selected. The final titer, yield and total amount of lysine produced by RS3 in a 5-L batch fermentation reached 155.0 ± 1.4 g/L, 0.59 ± 0.02 g lysine/g glucose, and 605.6 ± 23.5 g, with improvements of 14.8%, 9.3%, and 16.7%, respectively. Further metabolomics and genomics analyses, coupled with molecular biology studies revealed that mutations SpeBA302V, AtpBS165N and SecYM145V mainly contributed both to improved cell integrity under stress conditions and enhanced metabolic flux into lysine synthesis. CONCLUSIONS Our present study indicates that improving a lysine hyperproducer by GREACE-assisted ALE in its stressful living environment is efficient and effective. Accordingly, this is a promising method for improving other valuable chemical hyperproducers.
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Affiliation(s)
- Xiaowei Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Qinggang Li
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Cunmin Sun
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaomei Zheng
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Xuan Guo
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Xiaomeng Ni
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Wenjuan Zhou
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Yanmei Guo
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Ping Zheng
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Ning Chen
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Jibin Sun
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanhe Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
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13
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Stress-induced formation of cell wall-deficient cells in filamentous actinomycetes. Nat Commun 2018; 9:5164. [PMID: 30514921 PMCID: PMC6279842 DOI: 10.1038/s41467-018-07560-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/09/2018] [Indexed: 12/20/2022] Open
Abstract
The cell wall is a shape-defining structure that envelopes almost all bacteria and protects them from environmental stresses. Bacteria can be forced to grow without a cell wall under certain conditions that interfere with cell wall synthesis, but the relevance of these wall-less cells (known as L-forms) is unclear. Here, we show that several species of filamentous actinomycetes have a natural ability to generate wall-deficient cells in response to hyperosmotic stress, which we call S-cells. This wall-deficient state is transient, as S-cells are able to switch to the normal mycelial mode of growth. However, prolonged exposure of S-cells to hyperosmotic stress yields variants that are able to proliferate indefinitely without their cell wall, similarly to L-forms. We propose that formation of wall-deficient cells in actinomycetes may serve as an adaptation to osmotic stress. Bacteria can be forced to grow without cell wall if cell wall synthesis is inhibited. Here Ramijan et al. show that, in filamentous actinomycetes, hyperosmotic stress induces formation of wall-deficient cells that can switch to normal mycelial growth, or mutate and proliferate indefinitely as wall-less forms.
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Deutch CE. l-Proline catabolism by the high G + C Gram-positive bacterium Paenarthrobacter aurescens strain TC1. Antonie van Leeuwenhoek 2018; 112:237-251. [DOI: 10.1007/s10482-018-1148-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
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