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De Anda-Mora KL, Tavares-Carreón F, Alvarez C, Barahona S, Becerril-García MA, Treviño-Rangel RJ, García-Contreras R, Andrade A. Increased Proteolytic Activity of Serratia marcescens Clinical Isolate HU1848 Is Associated with Higher eepR Expression. Pol J Microbiol 2024; 73:11-20. [PMID: 38437469 PMCID: PMC10911700 DOI: 10.33073/pjm-2024-002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/14/2023] [Indexed: 03/06/2024] Open
Abstract
Serratia marcescens is a global opportunistic pathogen. In vitro cytotoxicity of this bacterium is mainly related to metalloprotease serralysin (PrtS) activity. Proteolytic capability varies among the different isolates. Here, we characterized protease production and transcriptional regulators at 37°C of two S. marcescens isolates from bronchial expectorations, HU1848 and SmUNAM836. As a reference strain the insect pathogen S. marcescens Db10 was included. Zymography of supernatant cultures revealed a single (SmUNAM836) or double proteolytic zones (HU1848 and Db10). Mass spectrometry confirmed the identity of PrtS and the serralysin-like protease SlpB from supernatant samples. Elevated proteolytic activity and prtS expression were evidenced in the HU1848 strain through azocasein degradation and qRT-PCR, respectively. Evaluation of transcriptional regulators revealed higher eepR expression in HU1848, whereas cpxR and hexS transcriptional levels were similar between studied strains. Higher eepR expression in HU1848 was further confirmed through an in vivo transcriptional assay. Moreover, two putative CpxR binding motifs were identified within the eepR regulatory region. EMSA validated the interaction of CpxR with both motifs. The evaluation of eepR transcription in a cpxR deletion strain indicated that CpxR negatively regulates eepR. Sequence conservation suggests that regulation of eepR by CpxR is common along S. marcescens species. Overall, our data incorporates CpxR to the complex regulatory mechanisms governing eepR expression and associates the increased proteolytic activity of the HU1848 strain with higher eepR transcription. Based on the global impact of EepR in secondary metabolites production, our work contributes to understanding virulence factors variances across S. marcescens isolates.
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Affiliation(s)
- Karla L. De Anda-Mora
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Faviola Tavares-Carreón
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Carlos Alvarez
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Samantha Barahona
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Miguel A. Becerril-García
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Rogelio J. Treviño-Rangel
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Angel Andrade
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
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Yao Q, Xie T, Fu Y, Wan J, Zhang W, Gao X, Huang J, Sun D, Zhang F, Bei W, Lei L, Liu F. The CpxA/CpxR two-component system mediates regulation of Actinobacillus pleuropneumoniae cold growth. Front Microbiol 2022; 13:1079390. [PMID: 36619992 PMCID: PMC9816388 DOI: 10.3389/fmicb.2022.1079390] [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: 10/25/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Introduction To survive in various hostile environments, two-component system is an adaptive mechanism for diverse bacteria. Activity of the CpxA/CpxR two-component system contributes to coping with different stimuli, such as pH, osmotic and heat stress. Methods However, the role of the CpxA/CpxR system in cold resistance is little-known. In this study, we showed that CpxA/CpxRwas critical for A. pleuropneumoniae growth under cold stress. Results β-Galactosidaseanalysis showed that CpxA/CpxR positively regulated the predicted cold stress gene cspC. The mutant for cold stress gene cspC was impaired in the optimal growth of A. pleuropneumoniae under cold stress. Furthermore, electrophoretic mobility shift assays demonstrated that CpxR-P could directly regulate the transcription of the cold stress gene cspC. Discussion These results presented in this study illustrated that the CpxA/CpxR system plays an important role in cold resistance by upregulating expression of CspC. The data give new insights into how A. pleuropneumoniae survives in cold stress.
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Affiliation(s)
- Qing Yao
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Tingting Xie
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Yu Fu
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Jiajia Wan
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Wendie Zhang
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Xuejun Gao
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Jing Huang
- School of Foreign Languages, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Diangang Sun
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Fuxian Zhang
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Liancheng Lei
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China,College of Veterinary Medicine, Jilin University, Changchun, China,Liancheng Lei, ✉
| | - Feng Liu
- College of Animal Sciences, Yangtze University, Jingzhou, Hubei, China,*Correspondence: Feng Liu, ✉
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Stella NA, Romanowski EG, Brothers KM, Calvario RC, Shanks RMQ. IgaA Protein, GumB, Has a Global Impact on the Transcriptome and Surface Proteome of Serratia marcescens. Infect Immun 2022; 90:e0039922. [PMID: 36317876 PMCID: PMC9671016 DOI: 10.1128/iai.00399-22] [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: 09/07/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022] Open
Abstract
Bacterial stress response signaling systems, like the Rcs system are triggered by membrane and cell wall damaging compounds, including antibiotics and immune system factors. These regulatory systems help bacteria survive envelope stress by altering the transcriptome resulting in protective phenotypic changes that may also influence the virulence of the bacterium. This study investigated the role of the Rcs stress response system using a clinical keratitis isolate of Serratia marcescens with a mutation in the gumB gene. GumB, an IgaA ortholog, inhibits activation of the Rcs system, such that mutants have overactive Rcs signaling. Transcriptomic analysis indicated that approximately 15% of all S. marcescens genes were significantly altered with 2-fold or greater changes in expression in the ΔgumB mutant compared to the wild type, indicating a global transcriptional regulatory role for GumB. We further investigated the phenotypic consequences of two classes of genes with altered expression in the ΔgumB mutant expected to contribute to infections: serralysin metalloproteases PrtS, SlpB, and SlpE, and type I pili coded by fimABCD. Secreted fractions from the ΔgumB mutant had reduced cytotoxicity to a corneal cell line, and could be complemented by induced expression of prtS, but not cytolysin shlBA, phospholipase phlAB, or flagellar master regulator flhDC operons. Proteomic analysis, qRT-PCR, and type I pili-dependent yeast agglutination indicated an inhibitory role for the Rcs system in adhesin production. Together these data demonstrate GumB has a global impact on S. marcescens gene expression that had measurable effects on bacterial cytotoxicity and surface adhesin production.
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Affiliation(s)
- Nicholas A. Stella
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Eric G. Romanowski
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Kimberly M. Brothers
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Rachel C. Calvario
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Robert M. Q. Shanks
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
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Garcia L, Molina MC, Padgett-Pagliai KA, Torres PS, Bruna RE, García Véscovi E, González CF, Gadea J, Marano MR. A serralysin-like protein of Candidatus Liberibacter asiaticus modulates components of the bacterial extracellular matrix. Front Microbiol 2022; 13:1006962. [DOI: 10.3389/fmicb.2022.1006962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Huanglongbing (HLB), the current major threat for Citrus species, is caused by intracellular alphaproteobacteria of the genus Candidatus Liberibacter (CaL), with CaL asiaticus (CLas) being the most prevalent species. This bacterium inhabits phloem cells and is transmitted by the psyllid Diaphorina citri. A gene encoding a putative serralysin-like metalloprotease (CLIBASIA_01345) was identified in the CLas genome. The expression levels of this gene were found to be higher in citrus leaves than in psyllids, suggesting a function for this protease in adaptation to the plant environment. Here, we study the putative role of CLas-serralysin (Las1345) as virulence factor. We first assayed whether Las1345 could be secreted by two different surrogate bacteria, Rhizobium leguminosarum bv. viciae A34 (A34) and Serratia marcescens. The protein was detected only in the cellular fraction of A34 and S. marcescens expressing Las1345, and increased protease activity of those bacteria by 2.55 and 4.25-fold, respectively. In contrast, Las1345 expressed in Nicotiana benthamiana leaves did not show protease activity nor alterations in the cell membrane, suggesting that Las1345 do not function as a protease in the plant cell. Las1345 expression negatively regulated cell motility, exopolysaccharide production, and biofilm formation in Xanthomonas campestris pv. campestris (Xcc). This bacterial phenotype was correlated with reduced growth and survival on leaf surfaces as well as reduced disease symptoms in N. benthamiana and Arabidopsis. These results support a model where Las1345 could modify extracellular components to adapt bacterial shape and appendages to the phloem environment, thus contributing to virulence.
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Araújo RG, Zavala NR, Castillo-Zacarías C, Barocio ME, Hidalgo-Vázquez E, Parra-Arroyo L, Rodríguez-Hernández JA, Martínez-Prado MA, Sosa-Hernández JE, Martínez-Ruiz M, Chen WN, Barceló D, Iqbal HM, Parra-Saldívar R. Recent Advances in Prodigiosin as a Bioactive Compound in Nanocomposite Applications. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27154982. [PMID: 35956931 PMCID: PMC9370345 DOI: 10.3390/molecules27154982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 07/23/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022]
Abstract
Bionanocomposites based on natural bioactive entities have gained importance due to their abundance; renewable and environmentally benign nature; and outstanding properties with applied perspective. Additionally, their formulation with biological molecules with antimicrobial, antioxidant, and anticancer activities has been produced nowadays. The present review details the state of the art and the importance of this pyrrolic compound produced by microorganisms, with interest towards Serratia marcescens, including production strategies at a laboratory level and scale-up to bioreactors. Promising results of its biological activity have been reported to date, and the advances and applications in bionanocomposites are the most recent strategy to potentiate and to obtain new carriers for the transport and controlled release of prodigiosin. Prodigiosin, a bioactive secondary metabolite, produced by Serratia marcescens, is an effective proapoptotic agent against bacterial and fungal strains as well as cancer cell lines. Furthermore, this molecule presents antioxidant activity, which makes it ideal for treating wounds and promoting the general improvement of the immune system. Likewise, some of the characteristics of prodigiosin, such as hydrophobicity, limit its use for medical and biotechnological applications; however, this can be overcome by using it as a component of a bionanocomposite. This review focuses on the chemistry and the structure of the bionanocomposites currently developed using biorenewable resources. Moreover, the work illuminates recent developments in pyrrole-based bionanocomposites, with special insight to its application in the medical area.
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Affiliation(s)
- Rafael G. Araújo
- Tecnologico de Monterrey, Institute of Advanced Materials for Sustainable Manufacturing Monterrey, Monterrey 64849, Mexico
| | - Natalia Rodríguez Zavala
- Chemical & Biochemical Engineering Department, Tecnológico Nacional de México-Instituto Tecnológico de Durango (TecNM-ITD), Blvd. Felipe Pescador 1830 Ote. Durango, Durango 34080, Mexico
| | - Carlos Castillo-Zacarías
- Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ingeniería Ambiental, Ciudad Universitaria S/N, San Nicolás de los Garza 66455, Mexico
| | - Mario E. Barocio
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey 64849, Mexico
| | | | - Lizeth Parra-Arroyo
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey 64849, Mexico
| | | | - María Adriana Martínez-Prado
- Chemical & Biochemical Engineering Department, Tecnológico Nacional de México-Instituto Tecnológico de Durango (TecNM-ITD), Blvd. Felipe Pescador 1830 Ote. Durango, Durango 34080, Mexico
| | - Juan Eduardo Sosa-Hernández
- Tecnologico de Monterrey, Institute of Advanced Materials for Sustainable Manufacturing Monterrey, Monterrey 64849, Mexico
| | - Manuel Martínez-Ruiz
- Tecnologico de Monterrey, Institute of Advanced Materials for Sustainable Manufacturing Monterrey, Monterrey 64849, Mexico
| | - Wei Ning Chen
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637457, Singapore
| | - Damià Barceló
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, 08034 Barcelona, Spain
- Catalan Institute for Water Research (ICRA-CERCA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, 17003 Girona, Spain
- Sustainability Cluster, School of Engineering, UPES, Dehradun 248007, India
| | - Hafiz M.N. Iqbal
- Tecnologico de Monterrey, Institute of Advanced Materials for Sustainable Manufacturing Monterrey, Monterrey 64849, Mexico
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey 64849, Mexico
- Correspondence: (H.M.N.I.); (R.P.-S.)
| | - Roberto Parra-Saldívar
- Tecnologico de Monterrey, Institute of Advanced Materials for Sustainable Manufacturing Monterrey, Monterrey 64849, Mexico
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey 64849, Mexico
- Correspondence: (H.M.N.I.); (R.P.-S.)
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Sina Rahme B, Lestradet M, Di Venanzio G, Ayyaz A, Yamba MW, Lazzaro M, Liégeois S, Garcia Véscovi E, Ferrandon D. The fliR gene contributes to the virulence of S. marcescens in a Drosophila intestinal infection model. Sci Rep 2022; 12:3068. [PMID: 35197500 PMCID: PMC8866479 DOI: 10.1038/s41598-022-06780-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 01/24/2022] [Indexed: 12/05/2022] Open
Abstract
Serratia marcescens is an opportunistic bacterium that infects a wide range of hosts including humans. It is a potent pathogen in a septic injury model of Drosophila melanogaster since a few bacteria directly injected in the body cavity kill the insect within a day. In contrast, flies do not succumb to ingested bacteria for days even though some bacteria cross the intestinal barrier into the hemolymph within hours. The mechanisms by which S. marcescens attacks enterocytes and damages the intestinal epithelium remain uncharacterized. To better understand intestinal infections, we performed a genetic screen for loss of virulence of ingested S. marcescens and identified FliR, a structural component of the flagellum, as a virulence factor. Next, we compared the virulence of two flagellum mutants fliR and flhD in two distinct S. marcescens strains. Both genes are required for S. marcescens to escape the gut lumen into the hemocoel, indicating that the flagellum plays an important role for the passage of bacteria through the intestinal barrier. Unexpectedly, fliR but not flhD is involved in S. marcescens-mediated damages of the intestinal epithelium that ultimately contribute to the demise of the host. Our results therefore suggest a flagellum-independent role for fliR in bacterial virulence.
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Affiliation(s)
- Bechara Sina Rahme
- Université de Strasbourg, Strasbourg, France
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France
| | - Matthieu Lestradet
- Université de Strasbourg, Strasbourg, France
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France
| | - Gisela Di Venanzio
- Instituto de Biología Molecular y Cellular de Rosario, Consejo Nacional de Investigaciones Cientificas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Arshad Ayyaz
- Université de Strasbourg, Strasbourg, France
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France
- Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Miriam Wennida Yamba
- Université de Strasbourg, Strasbourg, France
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France
| | - Martina Lazzaro
- Instituto de Biología Molecular y Cellular de Rosario, Consejo Nacional de Investigaciones Cientificas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Samuel Liégeois
- Université de Strasbourg, Strasbourg, France
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France
| | - Eleonora Garcia Véscovi
- Instituto de Biología Molecular y Cellular de Rosario, Consejo Nacional de Investigaciones Cientificas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Dominique Ferrandon
- Université de Strasbourg, Strasbourg, France.
- UPR 9022 du CNRS, Institut de Biologie Moléculaire du CNRS, CNRS, Strasbourg, France.
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Pan X, Tang M, You J, Osire T, Sun C, Fu W, Yi G, Yang T, Yang ST, Rao Z. PsrA is a novel regulator contributes to antibiotic synthesis, bacterial virulence, cell motility and extracellular polysaccharides production in Serratia marcescens. Nucleic Acids Res 2021; 50:127-148. [PMID: 34893884 PMCID: PMC8754645 DOI: 10.1093/nar/gkab1186] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/13/2021] [Accepted: 12/03/2021] [Indexed: 12/23/2022] Open
Abstract
Serratia marcescens is a Gram-negative bacterium of the Enterobacteriaceae family that can produce numbers of biologically active secondary metabolites. However, our understanding of the regulatory mechanisms behind secondary metabolites biosynthesis in S. marcescens remains limited. In this study, we identified an uncharacterized LysR family transcriptional regulator, encoding gene BVG90_12635, here we named psrA, that positively controlled prodigiosin synthesis in S. marcescens. This phenotype corresponded to PsrA positive control of transcriptional of the prodigiosin-associated pig operon by directly binding to a regulatory binding site (RBS) and an activating binding site (ABS) in the promoter region of the pig operon. We demonstrated that L-proline is an effector for the PsrA, which enhances the binding affinity of PsrA to its target promoters. Using transcriptomics and further experiments, we show that PsrA indirectly regulates pleiotropic phenotypes, including serrawettin W1 biosynthesis, extracellular polysaccharide production, biofilm formation, swarming motility and T6SS-mediated antibacterial activity in S. marcescens. Collectively, this study proposes that PsrA is a novel regulator that contributes to antibiotic synthesis, bacterial virulence, cell motility and extracellular polysaccharides production in S. marcescens and provides important clues for future studies exploring the function of the PsrA and PsrA-like proteins which are widely present in many other bacteria.
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Affiliation(s)
- Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Mi Tang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Tolbert Osire
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Changhao Sun
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Weilai Fu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China.,Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd., Zhangzhou 363500, China
| | - Ganfeng Yi
- Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd., Zhangzhou 363500, China
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Shang-Tian Yang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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Enhanced Prodigiosin Production in Serratia marcescens JNB5-1 by Introduction of a Polynucleotide Fragment into the pigN 3' Untranslated Region and Disulfide Bonds into O-Methyl Transferase (PigF). Appl Environ Microbiol 2021; 87:e0054321. [PMID: 34232745 DOI: 10.1128/aem.00543-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In Serratia marcescens JNB5-1, prodigiosin was highly produced at 30°C, but it was noticeably repressed at ≥37°C. Our initial results demonstrated that both the production and the stability of the O-methyl transferase (PigF) and oxidoreductase (PigN) involved in the prodigiosin pathway in S. marcescens JNB5-1 sharply decreased at ≥37°C. Therefore, in this study, we improved mRNA stability and protein production using de novo polynucleotide fragments (PNFs) and the introduction of disulfide bonds, respectively, and observed their effects on prodigiosin production. Our results demonstrate that adding PNFs at the 3' untranslated regions of pigF and pigN significantly improved the mRNA half-lives of these genes, leading to an increase in the transcript and expression levels. Subsequently, the introduction of disulfide bonds in pigF improved the thermal stability, pH stability, and copper ion resistance of PigF. Finally, shake flask fermentation showed that the prodigiosin titer with the engineered S. marcescens was increased by 61.38% from 5.36 to 8.65 g/liter compared to the JNB5-1 strain at 30°C and, significantly, the prodigiosin yield increased 2.05-fold from 0.38 to 0.78 g/liter at 37°C. In this study, we revealed that the introduction of PNFs and disulfide bonds greatly improved the expression and stability of pigF and pigN, hence efficiently enhancing prodigiosin production with S. marcescens at 30 and 37°C. IMPORTANCE This study highlights a promising strategy to improve mRNA/enzyme stability and to increase production using de novo PNF libraries and the introduction of disulfide bonds into the protein. PNFs could increase the half-life of target gene mRNA and effectively prevent its degradation. Moreover, PNFs could increase the relative intensity of target genes without affecting the expression of other genes; as a result, it could alleviate the cellular burden compared to other regulatory elements such as promoters. In addition, we obtained a PigF variant with improved activity and stability by the introduction of disulfide bonds into PigF. Collectively, we demonstrate here a novel approach for improving mRNA/enzyme stability using PNFs, which results in enhanced prodigiosin production in S. marcescens at 30°C.
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Harshaw NS, Stella NA, Lehner KM, Romanowski EG, Kowalski RP, Shanks RMQ. Antibiotics Used in Empiric Treatment of Ocular Infections Trigger the Bacterial Rcs Stress Response System Independent of Antibiotic Susceptibility. Antibiotics (Basel) 2021; 10:antibiotics10091033. [PMID: 34572615 PMCID: PMC8470065 DOI: 10.3390/antibiotics10091033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 12/02/2022] Open
Abstract
The Rcs phosphorelay is a bacterial stress response system that responds to envelope stresses and in turn controls several virulence-associated pathways, including capsule, flagella, and toxin biosynthesis, of numerous bacterial species. The Rcs system also affects antibiotic tolerance, biofilm formation, and horizontal gene transfer. The Rcs system of the ocular bacterial pathogen Serratia marcescens was recently demonstrated to influence ocular pathogenesis in a rabbit model of keratitis, with Rcs-defective mutants causing greater pathology and Rcs-activated strains demonstrating reduced inflammation. The Rcs system is activated by a variety of insults, including β-lactam antibiotics and polymyxin B. In this study, we developed three luminescence-based transcriptional reporters for Rcs system activity and used them to test whether antibiotics used for empiric treatment of ocular infections influence Rcs system activity in a keratitis isolate of S. marcescens. These included antibiotics to which the bacteria were susceptible and resistant. Results indicate that cefazolin, ceftazidime, polymyxin B, and vancomycin activate the Rcs system to varying degrees in an RcsB-dependent manner, whereas ciprofloxacin and tobramycin activated the promoter fusions, but in an Rcs-independent manner. Although minimum inhibitory concentration (MIC) analysis demonstrated resistance of the test bacteria to polymyxin B and vancomycin, the Rcs system was activated by sub-inhibitory concentrations of these antibiotics. Together, these data indicate that a bacterial stress system that influences numerous pathogenic phenotypes and drug-tolerance is influenced by different classes of antibiotics despite the susceptibility status of the bacterium.
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10
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Comparative transcriptome analysis reveals metabolic regulation of prodigiosin in Serratia marcescens. ACTA ACUST UNITED AC 2021. [DOI: 10.1007/s43393-021-00028-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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A CpxR-Regulated zapD Gene Involved in Biofilm Formation of Uropathogenic Proteus mirabilis. Infect Immun 2020; 88:IAI.00207-20. [PMID: 32284373 DOI: 10.1128/iai.00207-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 02/07/2023] Open
Abstract
Proteus mirabilis, a frequent uropathogen, forms extensive biofilms on catheters that are infamously difficult to treat. To explore the mechanisms of biofilm formation by P. mirabilis, we performed in vivo transposon mutagenesis. A mutant with impaired biofilm formation was isolated. The mutant was found to have Tn5 inserted in the zapD gene, encoding an outer membrane protein of the putative type 1 secretion system ZapBCD. zapBCD and its upstream zapA gene, encoding a protease, constitute an operon under the control of CpxR, a two-component regulator. The cpxR mutant and zapA mutant strains also had a biofilm-forming defect. CpxR positively regulates the promoter activities of zapABCD, cpxP, and cpxR An electrophoretic mobility shift assay revealed that CpxR binds zapA promoter DNA. The loss of zapD reduced CpxR-regulated gene expression of cpxR, zapA, cpxP, and mrpA, the mannose-resistant Proteus-like (MR/P) fimbrial major subunit gene. The restoration of biofilm formation in the zapD mutant with a CpxR-expressing plasmid reinforces the idea that CpxR-mediated gene expression contributes to zapD-involved biofilm formation. In trans expression of zapBCD from a zapBCD-expressing plasmid also reestablished the biofilm formation ability of the cpxR mutant to a certain level. The zapD and cpxR mutants had significantly lower protease activity, adhesion, and autoaggregation ability and production of exopolysaccharides and extracellular DNA (eDNA) than did the wild type. Finally, we identified copper as a signal for CpxR to increase biofilm formation. The loss of cpxR or zapD abolished the copper-mediated biofilm upshift. CpxR was required for copper-induced expression of zapA and cpxR Taken together, these data highlight the important role of CpxR-regulated zapD in biofilm formation and the underlying mechanisms in P. mirabilis.
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Sun Y, Wang L, Pan X, Osire T, Fang H, Zhang H, Yang ST, Yang T, Rao Z. Improved Prodigiosin Production by Relieving CpxR Temperature-Sensitive Inhibition. Front Bioeng Biotechnol 2020; 8:344. [PMID: 32582647 PMCID: PMC7283389 DOI: 10.3389/fbioe.2020.00344] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/27/2020] [Indexed: 12/24/2022] Open
Abstract
Prodigiosin (PG) is a typical secondary metabolite mainly produced by Serratia marcescens. CpxR protein is an OmpR family transcriptional regulator in Gram-negative bacteria. Firstly, it was found that insertion mutation of cpxR in S. marcescens JNB 5-1 by a transposon Tn5G increased the production of PG. Results from the electrophoretic mobility shift assay (EMSA) indicated that CpxR could bind to the promoter of the pig gene cluster and repress the transcription levels of genes involved in PG biosynthesis in S. marcescens JNB 5-1. In the ΔcpxR mutant strain, the transcription levels of the pig gene cluster and the genes involved in the pathways of PG precursors, such as proline, pyruvate, serine, methionine, and S-adenosyl methionine, were significantly increased, hence promoting the production of PG. Subsequently, a fusion segment composed of the genes proC, serC, and metH, responsible for proline, serine, and methionine, was inserted into the cpxR gene in S. marcescens JNB 5-1. On fermentation by the resultant engineered S. marcescens, the highest PG titer reached 5.83 g/L and increased by 41.9%, relative to the parental strain. In this study, we revealed the role of CpxR in PG biosynthesis and provided an alternative strategy for the engineering of S. marcescens to enhance PG production.
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Affiliation(s)
- Yang Sun
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Lijun Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xuewei Pan
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Tolbert Osire
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Haitian Fang
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, Yinchuan, China.,School of Agriculture, Ningxia University, Yinchuan, China
| | - Huiling Zhang
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, Yinchuan, China.,School of Agriculture, Ningxia University, Yinchuan, China
| | - Shang-Tian Yang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, United States
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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LysR-Type Transcriptional Regulator MetR Controls Prodigiosin Production, Methionine Biosynthesis, Cell Motility, H 2O 2 Tolerance, Heat Tolerance, and Exopolysaccharide Synthesis in Serratia marcescens. Appl Environ Microbiol 2020; 86:AEM.02241-19. [PMID: 31791952 DOI: 10.1128/aem.02241-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 11/23/2019] [Indexed: 12/31/2022] Open
Abstract
Prodigiosin, a secondary metabolite produced by Serratia marcescens, has attracted attention due to its immunosuppressive, antimicrobial, and anticancer properties. However, information on the regulatory mechanism behind prodigiosin biosynthesis in S. marcescens remains limited. In this work, a prodigiosin-hyperproducing strain with the BVG90_22495 gene disrupted (ZK66) was selected from a collection of Tn5G transposon insertion mutants. Using real-time quantitative PCR (RT-qPCR) analysis, β-galactosidase assays, transcriptomics analysis, and electrophoretic mobility shift assays (EMSAs), the LysR-type regulator MetR encoded by the BVG90_22495 gene was found to affect prodigiosin synthesis, and this correlated with MetR directly binding to the promoter region of the prodigiosin-synthesis positive regulator PigP and hence negatively regulated the expression of the prodigiosin-associated pig operon. More analyses revealed that MetR regulated some other important cellular processes, including methionine biosynthesis, cell motility, H2O2 tolerance, heat tolerance, exopolysaccharide synthesis, and biofilm formation in S. marcescens Although MetR protein is highly conserved in many bacteria, we report here on the LysR-type regulator MetR exhibiting novel roles in negatively regulating prodigiosin synthesis and positively regulating heat tolerance, exopolysaccharide synthesis, and biofilm formation.IMPORTANCE Serratia marcescens, a Gram-negative bacterium, is found in a wide range of ecological niches and can produce several secondary metabolites, including prodigiosin, althiomycin, and serratamolide. Among them, prodigiosin shows diverse functions as an immunosuppressant, antimicrobial, and anticancer agent. However, the regulatory mechanisms behind prodigiosin synthesis in S. marcescens are not completely understood. Here, we adapted a transposon mutant library to identify the genes related to prodigiosin synthesis, and the BVG90_22495 gene encoding the LysR-type regulator MetR was found to negatively regulate prodigiosin synthesis. The molecular mechanism of the metR mutant hyperproducing prodigiosin was investigated. Additionally, we provided evidence supporting new roles for MetR in regulating methionine biosynthesis, cell motility, heat tolerance, H2O2 tolerance, and exopolysaccharide synthesis in S. marcescens Collectively, this work provides novel insight into regulatory mechanisms of prodigiosin synthesis and uncovers novel roles for the highly conserved MetR protein in regulating prodigiosin synthesis, heat tolerance, exopolysaccharide (EPS) synthesis, and biofilm formation.
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Mechaly AE, Haouz A, Sassoon N, Buschiazzo A, Betton JM, Alzari PM. Conformational plasticity of the response regulator CpxR, a key player in Gammaproteobacteria virulence and drug-resistance. J Struct Biol 2018; 204:165-171. [DOI: 10.1016/j.jsb.2018.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/27/2023]
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