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Zhang N, Li T, Pan H, Wang Y, Li Q, Luan J, He X, Shi W, Li Y, Wang C, Zhang F, Hu W. Genetic components of Escherichia coli involved in its complex prey-predator interaction with Myxococcus xanthus. Front Microbiol 2023; 14:1304874. [PMID: 38116529 PMCID: PMC10728724 DOI: 10.3389/fmicb.2023.1304874] [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: 09/30/2023] [Accepted: 11/13/2023] [Indexed: 12/21/2023] Open
Abstract
Myxococcus xanthus and Escherichia coli represent a well-studied microbial predator-prey pair frequently examined in laboratory settings. While significant progress has been made in comprehending the mechanisms governing M. xanthus predation, various aspects of the response and defensive mechanisms of E. coli as prey remain elusive. In this study, the E. coli MG1655 large-scale chromosome deletion library was screened, and a mutant designated as ME5012 was identified to possess significantly reduced susceptibility to predation by M. xanthus. Within the deleted region of ME5012 encompassing seven genes, the significance of dusB and fis genes in driving the observed phenotype became apparent. Specifically, the deletion of fis resulted in a notable reduction in flagellum production in E. coli, contributing to a certain level of resistance against predation by M. xanthus. Meanwhile, the removal of dusB in E. coli led to diminished inducibility of myxovirescin A production by M. xanthus, accompanied by a slight decrease in susceptibility to myxovirescin A. These findings shed light on the molecular mechanisms underlying the complex interaction between M. xanthus and E. coli in a predatory context.
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Affiliation(s)
- Ning Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Tingyi Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Hongwei Pan
- Department of Clinical Laboratory, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Yipeng Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Qi Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Jia Luan
- Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Xuesong He
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, United States
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Wenyuan Shi
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, United States
| | - Yuezhong Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Chuandong Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Fengyu Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
| | - Wei Hu
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China
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2
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Müller S, DeLeon O, Atkinson SN, Saravia F, Kellogg S, Shank EA, Kirby JR. Thiocillin contributes to the ecological fitness of Bacillus cereus ATCC 14579 during interspecies interactions with Myxococcus xanthus. Front Microbiol 2023; 14:1295262. [PMID: 38075900 PMCID: PMC10704990 DOI: 10.3389/fmicb.2023.1295262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/09/2023] [Indexed: 02/12/2024] Open
Abstract
The soil-dwelling delta-proteobacterium Myxococcus xanthus is a model organism to study predation and competition. M. xanthus preys on a broad range of bacteria mediated by lytic enzymes, exopolysaccharides, Type-IV pilus-based motility, and specialized metabolites. Competition between M. xanthus and prey bacterial strains with various specialized metabolite profiles indicates a range of fitness, suggesting that specialized metabolites contribute to prey survival. To expand our understanding of how specialized metabolites affect predator-prey dynamics, we assessed interspecies interactions between M. xanthus and two strains of Bacillus cereus. While strain ATCC 14579 resisted predation, strain T was found to be highly sensitive to M. xanthus predation. The interaction between B. cereus ATCC 14579 and M. xanthus appears to be competitive, resulting in population loss for both predator and prey. Genome analysis revealed that ATCC 14579 belongs to a clade that possesses the biosynthetic gene cluster for production of thiocillins, whereas B. cereus strain T lacks those genes. Further, purified thiocillin protects B. cereus strains unable to produce this specialized metabolite, strengthening the finding that thiocillin protects against predation and contributes to the ecological fitness of B. cereus ATCC 14579. Lastly, strains that produce thiocillin appear to confer some level of protection to their own antibiotic by encoding an additional copy of the L11 ribosomal protein, a known target for thiopeptides. This work highlights the importance of specialized metabolites affecting predator-prey dynamics in soil microenvironments.
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Affiliation(s)
- Susanne Müller
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Orlando DeLeon
- Department of Medicine, University of Chicago Pritzker School of Medicine, Chicago, IL, United States
| | - Samantha N. Atkinson
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Fatima Saravia
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Stephanie Kellogg
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Elizabeth A. Shank
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worchester, MA, United States
| | - John R. Kirby
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
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3
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Kaimer C, Weltzer ML, Wall D. Two reasons to kill: predation and kin discrimination in myxobacteria. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001372. [PMID: 37494115 PMCID: PMC10433427 DOI: 10.1099/mic.0.001372] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 07/15/2023] [Indexed: 07/27/2023]
Abstract
Myxobacteria are social microbial predators that use cell-cell contacts to identify bacterial or fungal prey and to differentiate kin relatives to initiate cellular responses. For prey killing, they assemble Tad-like and type III-like secretion systems at contact sites. For kin discrimination (KD), they assemble outer membrane exchange complexes composed of the TraA and TraB receptors at contacts sites. A type VI secretion system and Rhs proteins also mediate KD. Following cellular recognition, these systems deliver appropriate effectors into target cells. For prey, this leads to cell death and lysis for nutrient consumption by myxobacteria. In KD, a panel of effectors are delivered, and if adjacent cells are clonal cells, resistance ensues because they express a cognate panel of immunity factors; while nonkin lack complete immunity and are intoxicated. This review compares and contrasts recent findings from these systems in myxobacteria.
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Affiliation(s)
- Christine Kaimer
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Michael L. Weltzer
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
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4
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Soto MJ, Pérez J, Muñoz-Dorado J, Contreras-Moreno FJ, Moraleda-Muñoz A. Transcriptomic response of Sinorhizobium meliloti to the predatory attack of Myxococcus xanthus. Front Microbiol 2023; 14:1213659. [PMID: 37405170 PMCID: PMC10315480 DOI: 10.3389/fmicb.2023.1213659] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/01/2023] [Indexed: 07/06/2023] Open
Abstract
Bacterial predation impacts microbial community structures, which can have both positive and negative effects on plant and animal health and on environmental sustainability. Myxococcus xanthus is an epibiotic soil predator with a broad range of prey, including Sinorhizobium meliloti, which establishes nitrogen-fixing symbiosis with legumes. During the M. xanthus-S. meliloti interaction, the predator must adapt its transcriptome to kill and lyse the target (predatosome), and the prey must orchestrate a transcriptional response (defensome) to protect itself against the biotic stress caused by the predatory attack. Here, we describe the transcriptional changes taking place in S. meliloti in response to myxobacterial predation. The results indicate that the predator induces massive changes in the prey transcriptome with up-regulation of protein synthesis and secretion, energy generation, and fatty acid (FA) synthesis, while down-regulating genes required for FA degradation and carbohydrate transport and metabolism. The reconstruction of up-regulated pathways suggests that S. meliloti modifies the cell envelop by increasing the production of different surface polysaccharides (SPSs) and membrane lipids. Besides the barrier role of SPSs, additional mechanisms involving the activity of efflux pumps and the peptide uptake transporter BacA, together with the production of H2O2 and formaldehyde have been unveiled. Also, the induction of the iron-uptake machinery in both predator and prey reflects a strong competition for this metal. With this research we complete the characterization of the complex transcriptional changes that occur during the M. xanthus-S. meliloti interaction, which can impact the establishment of beneficial symbiosis with legumes.
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Affiliation(s)
- María José Soto
- Departamento de Biotecnología y Protección Ambiental, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | | | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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Yang Y, Tao H, Ma W, Wang N, Chen X, Wang W. Lysis profile and preference of Myxococcus sp. PT13 for typical soil bacteria. Front Microbiol 2023; 14:1211756. [PMID: 37378286 PMCID: PMC10291197 DOI: 10.3389/fmicb.2023.1211756] [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: 04/25/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Introduction Myxococcus sp. PT13 is a wild strain with multiple predatory properties that prey on multiple model microorganisms preserved in the laboratory. However, the lysis spectrum of PT13 on typical soil bacteria and its driving effect on soil microecosystems are still unclear. Methods In this study, the lawn predation method was used to determine the predation diameter of 62 typical soil bacteria by myxobacteria PT13 and analyze their lysis spectra. Results and Discussion The results showed that PT13 had a predation diameter greater than 15 mm against typical soil microorganisms such as Aeromonas, Bacillus, Brevibacterium, Fictibacillus, Glutamicibacter, Herbaspirillum, and Leifsonia and had an outstanding lysis effect but a significant preference (p < 0.05). Absolute high-throughput sequencing results showed that PT13 predation drove the microcosmic system composed of 16 bacterial genera, with a significant decrease in the Shannon index by 11.8% (CK = 2.04, D = 1.80) and a significant increase in the Simpson index by 45.0% (CK = 0.20, D = 0.29). The results of principal coordinate analysis (PCoA) showed that myxobacterial addition significantly disturbed the microcosmic microbial community structure (ANOSIM, p < 0.05). LEfSe analysis showed that the relative and absolute abundances (copy numbers) of Bacillus, Pedobacter, Staphylococcus, Streptomyces and Fictibacillus decreased significantly very likely due to myxobacterial predation (p < 0.05). However, the predatory effect of PT13 also increased the relative or absolute abundances of some species, such as Sphingobacterium, Paenarthrobacter, Microbacterium, and Leifsonia. It can be concluded that PT13 has a broad-spectrum lysis spectrum but poor cleavage ability for Streptomyces, and the interaction between complex microorganisms limits the predation effect of PT13 on some prey bacteria. This in turn allows some prey to coexist with myxobacteria. This paper will lay a theoretical foundation for the regulation of soil microecology dominated by myxobacteria.
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Kim Tiam S, Boubakri H, Bethencourt L, Abrouk D, Fournier P, Herrera-Belaroussi A. Genomic Insights of Alnus-Infective Frankia Strains Reveal Unique Genetic Features and New Evidence on Their Host-Restricted Lifestyle. Genes (Basel) 2023; 14:530. [PMID: 36833457 PMCID: PMC9956245 DOI: 10.3390/genes14020530] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 02/23/2023] Open
Abstract
The present study aimed to use comparative genomics to explore the relationships between Frankia and actinorhizal plants using a data set made of 33 Frankia genomes. The determinants of host specificity were first explored for "Alnus-infective strains" (i.e., Frankia strains belonging to Cluster Ia). Several genes were specifically found in these strains, including an agmatine deiminase which could possibly be involved in various functions as access to nitrogen sources, nodule organogenesis or plant defense. Within "Alnus-infective strains", Sp+ Frankia genomes were compared to Sp- genomes in order to elucidate the narrower host specificity of Sp+ strains (i.e., Sp+ strains being capable of in planta sporulation, unlike Sp- strains). A total of 88 protein families were lost in the Sp+ genomes. The lost genes were related to saprophytic life (transcriptional factors, transmembrane and secreted proteins), reinforcing the proposed status of Sp+ as obligatory symbiont. The Sp+ genomes were also characterized by a loss of genetic and functional paralogs, highlighting a reduction in functional redundancy (e.g., hup genes) or a possible loss of function related to a saprophytic lifestyle (e.g., genes involved in gas vesicle formation or recycling of nutrients).
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Affiliation(s)
- Sandra Kim Tiam
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
- UMR CNRS 5557 Ecologie Microbienne, INRA UMR 1418, Centre d’Etude des Substances Naturelles, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France
| | - Hasna Boubakri
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Lorine Bethencourt
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Danis Abrouk
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Pascale Fournier
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Aude Herrera-Belaroussi
- Université de Lyon, F-69361 Lyon, France, Université Claude Bernard Lyon 1, CNRS, UMR 5557, INRA UMR 1418, Ecologie Microbienne, F-69622 Villeurbanne, France
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7
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Phillips KE, Akbar S, Stevens DC. Concepts and conjectures concerning predatory performance of myxobacteria. Front Microbiol 2022; 13:1031346. [PMID: 36246230 PMCID: PMC9556981 DOI: 10.3389/fmicb.2022.1031346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/14/2022] [Indexed: 01/28/2023] Open
Abstract
Myxobacteria are excellent model organisms for investigation of predator-prey interactions and predatory shaping of microbial communities. This review covers interdisciplinary topics related to myxobacterial predation and provides current concepts and challenges for determining predatory performance. Discussed topics include the role of specialized metabolites during predation, genetic determinants for predatory performance, challenges associated with methodological differences, discrepancies between sequenced and environmental myxobacteria, and factors that influence predation.
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Affiliation(s)
- Kayleigh E. Phillips
- Department of BioMolecular Sciences, The University of Mississippi, Oxford, MS, United States
| | - Shukria Akbar
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, United States,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - D. Cole Stevens
- Department of BioMolecular Sciences, The University of Mississippi, Oxford, MS, United States,*Correspondence: D. Cole Stevens,
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8
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Dimunová D, Matoušková P, Podlipná R, Boušová I, Skálová L. The role of UDP-glycosyltransferases in xenobiotic-resistance. Drug Metab Rev 2022; 54:282-298. [DOI: 10.1080/03602532.2022.2083632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Diana Dimunová
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Petra Matoušková
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Radka Podlipná
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Praha 6 - Lysolaje, Czech Republic
| | - Iva Boušová
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Lenka Skálová
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
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9
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Hu Y, Li H, Min J, Yu Y, Liu W, Huang JW, Zhang L, Yang Y, Dai L, Chen CC, Guo RT. Crystal structure and biochemical analysis of the specialized deoxynivalenol-detoxifying glyoxalase SPG from Gossypium hirsutum. Int J Biol Macromol 2022; 200:388-396. [PMID: 35051496 DOI: 10.1016/j.ijbiomac.2022.01.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 01/01/2022] [Accepted: 01/09/2022] [Indexed: 11/24/2022]
Abstract
Deoxynivalenol (DON) and its acetylated derivatives such as 3-acetyldeoxynivalenol (3A-DON) and 15-acetyldeoxynivalenol (15A-DON) are notorious mycotoxins in Fusarium contaminated cereals, which pose a great threat to human and livestock health. The specialized glyoxalase I from Gossypium hirsutum (SPG) can lower the toxicity of 3A-DON by conducting isomerization to transfer C8 carbonyl to C7 and double bond from C9-C10 to C8-C9. Here we report that the substrate-flexible SPG can also recognize 15A-DON and DON, probably following the same isomerization mechanism as that for 3A-DON. The crystallographic, mutagenesis, and biochemical analyses revealed that SPG provides a hydrophobic pocket to accommodate the substrate and residue E167 might serve as the catalytic base. A variant SPGY62A that was constructed based on structure-based protein engineering exhibited elevated catalytic activity towards DON, 3A-DON, and 15A-DON by >70%. Furthermore, variant SPGY62A was successfully expressed in Pichia pastoris, whose catalytic activity was also compared to that produced in Escherichia coli. These results provide a blueprint for further protein engineering of SPG and reveal the potential applications of the enzyme in detoxifying DON, 3A-DON and 15A-DON.
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Affiliation(s)
- Yumei Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Hao Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jian Min
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yuanyuan Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Weidong Liu
- National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China
| | - Jian-Wen Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Lilan Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yunyun Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Longhai Dai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
| | - Chun-Chi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
| | - Rey-Ting Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
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10
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Wang DG, Niu L, Lin ZM, Wang JJ, Gao DF, Sui HY, Li YZ, Wu C. The Discovery and Biosynthesis of Nicotinic Myxochelins from an Archangium sp. SDU34. JOURNAL OF NATURAL PRODUCTS 2021; 84:2744-2748. [PMID: 34623817 DOI: 10.1021/acs.jnatprod.1c00524] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Myxobacteria are a prolific source of structurally diverse natural products, and one of the best-studied myxobacterial products is the siderophore myxochelin. Herein, we report two new compounds, myxochelins N (1) and O (2), that are nicotinic paralogs of myxochelin A, from the terrestrial myxobacterium Archangium sp. SDU34; 2 is functionalized with a rare 2-oxazolidinone. A precursor-feeding experiment implied that the biosynthesis of 1 or 2 was due to altered substrate specificity of the loading module of MxcE, which likely accepts nicotinic acid and benzoic acid instead of more conventional 2,3-dihydroxybenzoic acid. We also employed a phylogenomic approach to map the evolutionary relationships of the myxochelin biosynthetic gene clusters (BGCs) in all the available myxobacterial genomes, to pave the way for the future discovery of potentially hidden myxochelin derivatives. Although the biological function of 1 and 2 is unclear yet, this work underpins that even extensively studied BGCs in myxobacteria can still produce new chemistry.
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Affiliation(s)
- De-Gao Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
| | - Luo Niu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
| | - Zhao-Min Lin
- Institute of Medical Science, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, People's Republic of China
| | - Jing-Jing Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
| | - Dong-Fang Gao
- Institute of Medical Science, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, People's Republic of China
| | - Hai-Yan Sui
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
| | - Yue-Zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
| | - Changsheng Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, People's Republic of China
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11
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Akbar S, Phillips KE, Misra SK, Sharp JS, Stevens DC. Differential response to prey quorum signals indicates predatory specialization of myxobacteria and ability to predate Pseudomonas aeruginosa. Environ Microbiol 2021; 24:1263-1278. [PMID: 34674390 PMCID: PMC9257966 DOI: 10.1111/1462-2920.15812] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 09/20/2021] [Accepted: 10/07/2021] [Indexed: 11/29/2022]
Abstract
Multiomic analysis of transcriptional and metabolic responses from the predatory myxobacteria Myxococcus xanthus and Cystobacter ferrugineus exposed to prey signalling molecules of the acylhomoserine lactone and quinolone quorum signalling classes provided insight into predatory specialization. Acylhomoserine lactone quorum signals elicited a general response from both myxobacteria. We suggest that this is likely due to the generalist predator lifestyles of myxobacteria and ubiquity of acylhomoserine lactone signals. We also provide data that indicates the core homoserine lactone moiety included in all acylhomoserine lactone scaffolds to be sufficient to induce this general response. Comparing both myxobacteria, unique transcriptional and metabolic responses were observed from Cystobacter ferrugineus exposed to the quinolone signal 2‐heptylquinolin‐4(1H)‐one (HHQ) natively produced by Pseudomonas aeruginosa. We suggest that this unique response and ability to metabolize quinolone signals contribute to the superior predation of P. aeruginosa observed from C. ferrugineus. These results further demonstrate myxobacterial eavesdropping on prey signalling molecules and provide insight into how responses to exogenous signals might correlate with prey range of myxobacteria.
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Affiliation(s)
- Shukria Akbar
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA
| | - Kayleigh E Phillips
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA
| | - Sandeep K Misra
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA
| | - Joshua S Sharp
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA.,Department of Chemistry and Biochemistry, University of Mississippi, University, University, MS, USA
| | - D Cole Stevens
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA
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12
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The soil microbial food web revisited: Predatory myxobacteria as keystone taxa? THE ISME JOURNAL 2021; 15:2665-2675. [PMID: 33746204 PMCID: PMC8397742 DOI: 10.1038/s41396-021-00958-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/24/2021] [Accepted: 03/04/2021] [Indexed: 02/07/2023]
Abstract
Trophic interactions are crucial for carbon cycling in food webs. Traditionally, eukaryotic micropredators are considered the major micropredators of bacteria in soils, although bacteria like myxobacteria and Bdellovibrio are also known bacterivores. Until recently, it was impossible to assess the abundance of prokaryotes and eukaryotes in soil food webs simultaneously. Using metatranscriptomic three-domain community profiling we identified pro- and eukaryotic micropredators in 11 European mineral and organic soils from different climes. Myxobacteria comprised 1.5-9.7% of all obtained SSU rRNA transcripts and more than 60% of all identified potential bacterivores in most soils. The name-giving and well-characterized predatory bacteria affiliated with the Myxococcaceae were barely present, while Haliangiaceae and Polyangiaceae dominated. In predation assays, representatives of the latter showed prey spectra as broad as the Myxococcaceae. 18S rRNA transcripts from eukaryotic micropredators, like amoeba and nematodes, were generally less abundant than myxobacterial 16S rRNA transcripts, especially in mineral soils. Although SSU rRNA does not directly reflect organismic abundance, our findings indicate that myxobacteria could be keystone taxa in the soil microbial food web, with potential impact on prokaryotic community composition. Further, they suggest an overlooked, yet ecologically relevant food web module, independent of eukaryotic micropredators and subject to separate environmental and evolutionary pressures.
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13
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Akbar S, Stevens DC. Functional genomics study of Pseudomonas putida to determine traits associated with avoidance of a myxobacterial predator. Sci Rep 2021; 11:16445. [PMID: 34385565 PMCID: PMC8360965 DOI: 10.1038/s41598-021-96046-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022] Open
Abstract
Predation contributes to the structure and diversity of microbial communities. Predatory myxobacteria are ubiquitous to a variety of microbial habitats and capably consume a broad diversity of microbial prey. Predator-prey experiments utilizing myxobacteria have provided details into predatory mechanisms and features that facilitate consumption of prey. However, prey resistance to myxobacterial predation remains underexplored, and prey resistances have been observed exclusively from predator-prey experiments that included the model myxobacterium Myxococcus xanthus. Utilizing a predator-prey pairing that instead included the myxobacterium, Cystobacter ferrugineus, with Pseudomonas putida as prey, we observed surviving phenotypes capable of eluding predation. Comparative transcriptomics between P. putida unexposed to C. ferrugineus and the survivor phenotype suggested that increased expression of efflux pumps, genes associated with mucoid conversion, and various membrane features contribute to predator avoidance. Unique features observed from the survivor phenotype when compared to the parent P. putida include small colony variation, efflux-mediated antibiotic resistance, phenazine-1-carboxylic acid production, and increased mucoid conversion. These results demonstrate the utility of myxobacterial predator-prey models and provide insight into prey resistances in response to predatory stress that might contribute to the phenotypic diversity and structure of bacterial communities.
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Affiliation(s)
- Shukria Akbar
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA
| | - D Cole Stevens
- Department of BioMolecular Sciences, University of Mississippi, University, MS, USA.
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14
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Sydney N, Swain MT, So JMT, Hoiczyk E, Tucker NP, Whitworth DE. The Genetics of Prey Susceptibility to Myxobacterial Predation: A Review, Including an Investigation into Pseudomonas aeruginosa Mutations Affecting Predation by Myxococcus xanthus. Microb Physiol 2021; 31:57-66. [PMID: 33794538 DOI: 10.1159/000515546] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/22/2021] [Indexed: 11/19/2022]
Abstract
Bacterial predation is a ubiquitous and fundamental biological process, which influences the community composition of microbial ecosystems. Among the best characterised bacterial predators are the myxobacteria, which include the model organism Myxococcus xanthus. Predation by M. xanthus involves the secretion of antibiotic metabolites and hydrolytic enzymes, which results in the lysis of prey organisms and release of prey nutrients into the extracellular milieu. Due to the generalist nature of this predatory mechanism, M. xanthus has a broad prey range, being able to kill and consume Gram-negative/positive bacteria and fungi. Potential prey organisms have evolved a range of behaviours which protect themselves from attack by predators. In recent years, several investigations have studied the molecular responses of a broad variety of prey organisms to M. xanthus predation. It seems that the diverse mechanisms employed by prey belong to a much smaller number of general "predation resistance" strategies. In this mini-review, we present the current state of knowledge regarding M. xanthus predation, and how prey organisms resist predation. As previous molecular studies of prey susceptibility have focussed on individual genes/metabolites, we have also undertaken a genome-wide screen for genes of Pseudomonas aeruginosa which contribute to its ability to resist predation. P. aeruginosa is a World Health Organisation priority 1 antibiotic-resistant pathogen. It is metabolically versatile and has an array of pathogenic mechanisms, leading to its prevalence as an opportunistic pathogen. Using a library of nearly 5,500 defined transposon insertion mutants, we screened for "prey genes", which when mutated allowed increased predation by a fluorescent strain of M. xanthus. A set of candidate "prey proteins" were identified, which shared common functional roles and whose nature suggested that predation resistance by P. aeruginosa requires an effective metal/oxidative stress system, an intact motility system, and mechanisms for de-toxifying antimicrobial peptides.
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Affiliation(s)
- Natashia Sydney
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Martin T Swain
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Jeffery M T So
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Egbert Hoiczyk
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Nicholas P Tucker
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - David E Whitworth
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
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15
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Structural and biochemical studies of the glycosyltransferase Bs-YjiC from Bacillus subtilis. Int J Biol Macromol 2020; 166:806-817. [PMID: 33152360 DOI: 10.1016/j.ijbiomac.2020.10.238] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 09/19/2020] [Accepted: 10/30/2020] [Indexed: 02/05/2023]
Abstract
Glycosylation possess prominent biological and pharmacological significance in natural product and drug candidate synthesis. The glycosyltransferase YjiC, discovered from Bacillus subtilis (Bs-YjiC), shows potential applications in drug development due to its wide substrate spectrums. In order to elucidate its catalytic mechanism, we solved the crystal structure of Bs-YjiC, demonstrating that Bs-YjiC adopts a typical GT-B fold consisting of a flexible N-domain and a relatively rigid C-domain. Structural analysis coupled with site-directed mutagenesis studies revealed that site Ser277 was critical for Nucleoside Diphosphate (NDP) recognition, while Glu317, Gln318, Ser128 and Ser129 were crucial for glycosyl moiety recognition. Our results illustrate the structural basis for acceptor promiscuity in Bs-YjiC and provide a starting point for further protein engineering of Bs-YjiC in industrial and pharmaceutical applications.
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16
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Zhang P, Zhang L, Yue XJ, Tang YJ, Wu C, Li YZ. Effects of glycosylation on the bioactivity of rapamycin. Appl Microbiol Biotechnol 2020; 104:9125-9134. [PMID: 32940736 DOI: 10.1007/s00253-020-10895-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/30/2020] [Accepted: 09/05/2020] [Indexed: 12/01/2022]
Abstract
The macrolactone rapamycin (RAP) presents a broad range of bioactivities, but its clinical applications are compromised due to the poor water solubility and low bioavailability, which could probably be overcome by glycosylation. In this study, we tested a set of promiscuous glycosyltransferases (GTs) to modify rapamycin with four different sugar donors. BsGT-1 displayed the best glycosylation activity with a preference for UDP-glucose, and the glycosylation happened at C-28 or C-40 of rapamycin, producing rapamycin-40-O-β-D-glucoside (RG1), and two new compounds rapamycin-28-O-β-D-glucoside (RG2) and rapamycin-28,40-O-β-D-diglucoside (RG3). The glycosylation remarkably improved water solubility and almost completely abolished cytotoxicity but simultaneously attenuated the antifungal, antitumor, and immunosuppression bioactivities of rapamycin. We found the glycosylation at C-40 had less effect on the bioactivities than that at C-28. The molecular docking analysis revealed that the glycosylation, especially the glycosylation at C-28, weakened the hydrophobic and hydrogen bonding contacts between the rapamycin glucosides and the binding proteins: the FK506-binding protein (FKBP12) and the FKBP12-rapamycin binding (FRB) domain. This study highlights a succinct approach to expand the chemical diversity of the therapeutically important molecule rapamycin by using promiscuous glycosyltransferases. Moreover, the fact that glycosyl moieties at different positions of rapamycin affect bioactivity to different extents inspires further glycosylation engineering to improve properties of rapamycin. KEY POINTS: • Rapamycin was glycosylated efficiently by some promiscuous GTs. • Glycosylation improved water solubility, attenuated cytotoxicity, and bioactivities. • Glycosylation affected the interactions between ligand and binding proteins.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Lijuan Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xin-Jing Yue
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Ya-Jie Tang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Changsheng Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
| | - Yue-Zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
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17
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Pérez J, Contreras-Moreno FJ, Marcos-Torres FJ, Moraleda-Muñoz A, Muñoz-Dorado J. The antibiotic crisis: How bacterial predators can help. Comput Struct Biotechnol J 2020; 18:2547-2555. [PMID: 33033577 PMCID: PMC7522538 DOI: 10.1016/j.csbj.2020.09.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/30/2022] Open
Abstract
Discovery of antimicrobials in the past century represented one of the most important advances in public health. Unfortunately, the massive use of these compounds in medicine and other human activities has promoted the selection of pathogens that are resistant to one or several antibiotics. The current antibiotic crisis is creating an urgent need for research into new biological weapons with the ability to kill these superbugs. Although a proper solution requires this problem to be addressed in a variety of ways, the use of bacterial predators is emerging as an excellent strategy, especially when used as whole cell therapeutic agents, as a source of new antimicrobial agents by awakening silent metabolic pathways in axenic cultures, or as biocontrol agents. Moreover, studies on their prey are uncovering mechanisms of resistance that can be shared by pathogens, representing new targets for novel antimicrobial agents. In this review we discuss potential of the studies on predator-prey interaction to provide alternative solutions to the problem of antibiotic resistance.
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Key Words
- AR, antibiotic resistance
- ARB, antibiotic-resistant bacteria
- ARG, antibiotic-resistant gene
- Antibiotic crisis
- BALOs
- BALOs, Bdellovibrio and like organisms
- BGC, biosynthetic gene cluster
- Bacterial predators
- HGT, horizontal gene transfer
- MDRB, multi-drug resistant bacteria
- Myxobacteria
- NRPS, nonribosomal peptide synthetase
- OMV, outer membrane vesicle
- OSMAC, one strain many compounds
- PKS, polyketide synthase
- SM, secondary metabolite
- WHO, World Health Organization
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Affiliation(s)
- Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Avda. Fuentenueva s/n, Universidad de Granada, 18071 Granada, Spain
| | | | | | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Avda. Fuentenueva s/n, Universidad de Granada, 18071 Granada, Spain
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Avda. Fuentenueva s/n, Universidad de Granada, 18071 Granada, Spain
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18
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Zhang P, Zhang Z, Zhang L, Wang J, Wu C. Glycosyltransferase GT1 family: Phylogenetic distribution, substrates coverage, and representative structural features. Comput Struct Biotechnol J 2020; 18:1383-1390. [PMID: 32637037 PMCID: PMC7316871 DOI: 10.1016/j.csbj.2020.06.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/28/2020] [Accepted: 06/01/2020] [Indexed: 12/13/2022] Open
Abstract
The phylogenetic distribution of GT1 family enzymes showed domain-dependent pattern. The domain-dependent characterized GTs showed distinct substrates spectrum. Two regions that discriminate the GT1 enzymes from different domains were identified.
Glycosyltransferases (GTs) are responsible for transferring glycosyl moieties from activated sugar donors to certain acceptors, among which the GT1 family enzymes have been known for their outstanding glycosylation capacities toward diverse natural products, such as glycolipids, flavonoids and macrolides etc. However, there still lacks a systematic collation of this important family members. In this minireview, all the GT1 family sequences were phylogenetically analyzed, and the grouping of GT1 proteins exhibited a taxonomic life domain-dependent pattern, revealing many untapped clades of GTs. The further phylogenetic analysis of the characterized GTs facilitated the classification of substrates coverage of GT1 family enzymes from different life domains, whereby the GTs from bacteria can tolerate a wider spectrum of chemical skeletons as substrates, showing higher promiscuity than those from other domains. Furthermore, the sequence sizes of GTs from different domains were compared to understand their different substrates selectivity. Based on the multiple sequence alignments of 28 representative GT1 enzymes with crystal structures, two critical regions located in the N-terminal of GTs were identified, which were most variable among sequences from different taxonomic domains and essential for substrates binding and/or catalysis. The key roles of these two regions were validated by enumerating the influential residues that interacted with substrates in the representative structures from bacteria and plants. The atlas for GT1 family in terms of phylogeny, substrates selectivity, sequence length, and critical motifs provides the clues for the exploration of unknown GT1s and rational engineering of known enzymes, synthesizing novel promising glycoconjugates for pharmaceutical application.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Zheng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Lijuan Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Jingjing Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Changsheng Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
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Contreras-Moreno FJ, Muñoz-Dorado J, García-Tomsig NI, Martínez-Navajas G, Pérez J, Moraleda-Muñoz A. Copper and Melanin Play a Role in Myxococcus xanthus Predation on Sinorhizobium meliloti. Front Microbiol 2020; 11:94. [PMID: 32117124 PMCID: PMC7010606 DOI: 10.3389/fmicb.2020.00094] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/16/2020] [Indexed: 12/15/2022] Open
Abstract
Myxococcus xanthus is a soil myxobacterium that exhibits a complex lifecycle with two multicellular stages: cooperative predation and development. During predation, myxobacterial cells produce a wide variety of secondary metabolites and hydrolytic enzymes to kill and consume the prey. It is known that eukaryotic predators, such as ameba and macrophages, introduce copper and other metals into the phagosomes to kill their prey by oxidative stress. However, the role of metals in bacterial predation has not yet been established. In this work, we have addressed the role of copper during predation of M. xanthus on Sinorhizobium meliloti. The use of biosensors, variable pressure scanning electron microscopy, high-resolution scanning transmission electron microscopy, and energy dispersive X ray analysis has revealed that copper accumulates in the region where predator and prey collide. This accumulation of metal up-regulates the expression of several mechanisms involved in copper detoxification in the predator (the P1B-ATPase CopA, the multicopper oxidase CuoA and the tripartite pump Cus2), and the production by the prey of copper-inducible melanin, which is a polymer with the ability to protect cells from oxidative stress. We have identified two genes in S. meliloti (encoding a tyrosinase and a multicopper oxidase) that participate in the biosynthesis of melanin. Analysis of prey survivability in the co-culture of M. xanthus and a mutant of S. meliloti in which the two genes involved in melanin biosynthesis have been deleted has revealed that this mutant is more sensitive to predation than the wild-type strain. These results indicate that copper plays a role in bacterial predation and that melanin is used by the prey to defend itself from the predator. Taking into consideration that S. meliloti is a nitrogen-fixing bacterium in symbiosis with legumes that coexists in soils with M. xanthus and that copper is a common metal found in this habitat as a consequence of several human activities, these results provide clear evidence that the accumulation of this metal in the soil may influence the microbial ecosystems by affecting bacterial predatory activities.
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Affiliation(s)
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Natalia Isabel García-Tomsig
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain.,Estación Experimental del Zaidín, Granada, Spain
| | | | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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Thiery S, Kaimer C. The Predation Strategy of Myxococcus xanthus. Front Microbiol 2020; 11:2. [PMID: 32010119 PMCID: PMC6971385 DOI: 10.3389/fmicb.2020.00002] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/03/2020] [Indexed: 11/20/2022] Open
Abstract
Myxobacteria are ubiquitous in soil environments. They display a complex life cycle: vegetatively growing cells coordinate their motility to form multicellular swarms, which upon starvation aggregate into large fruiting bodies where cells differentiate into spores. In addition to growing as saprophytes, Myxobacteria are predators that actively kill bacteria of other species to consume their biomass. In this review, we summarize research on the predation behavior of the model myxobacterium Myxococcus xanthus, which can access nutrients from a broad spectrum of microorganisms. M. xanthus displays an epibiotic predation strategy, i.e., it induces prey lysis from the outside and feeds on the released biomass. This predatory behavior encompasses various processes: Gliding motility and induced cell reversals allow M. xanthus to encounter prey and to remain within the area to sweep up its biomass, which causes the characteristic “rippling” of preying populations. Antibiotics and secreted bacteriolytic enzymes appear to be important predation factors, which are possibly targeted to prey cells with the aid of outer membrane vesicles. However, certain bacteria protect themselves from M. xanthus predation by forming mechanical barriers, such as biofilms and mucoid colonies, or by secreting antibiotics. Further understanding the molecular mechanisms that mediate myxobacterial predation will offer fascinating insight into the reciprocal relationships of bacteria in complex communities, and might spur application-oriented research on the development of novel antibacterial strategies.
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Affiliation(s)
- Susanne Thiery
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Christine Kaimer
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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