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Yuan M, Chen G, Xiao Y, Qu Y, Ren Y. The mechanisms of yeast extracellular metabolites in stimulating microbial degradation of trichloroethylene: Physiological characteristics and omics analysis. ENVIRONMENTAL RESEARCH 2024; 255:119193. [PMID: 38777296 DOI: 10.1016/j.envres.2024.119193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
The biodegradation of Trichloroethylene (TCE) is limited by low microbial metabolic capacity but can be enhanced through biostimulation strategies. This study explored the physiological effects and potential molecular mechanisms of the yeast Yarrowia lipolytica extracellular metabolites (YEMs) on the degradation of TCE by Acinetobacter LT1. Results indicated that YEMs stimulated the efficiency of strain LT1 by 50.28%. At the physiological level, YEMs exhibited protective effects on cell morphology, reduced oxidative stress, lessened membrane damage, and enhanced energy production and conversion. Analysis of omics results revealed that the regulation of various metabolic pathways by YEMs improved the degradation of TCE. Furthermore, RT-qPCR showed that the genes encoding YhhW protein in TCE stress and YEMs stimulation groups were 1.72 and 3.22 times the control group, respectively. Molecular docking results showed that the conformation of YhhW after binding to TCE changed into a more active form, which enhanced enzyme activity. Therefore, it is speculated that YhhW is the primary degradative enzyme involved in the process of YEMs stimulating strain LT1 to degrade TCE. These results reveal how YEMs induce strain LT1 to enhance TCE degradation.
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Affiliation(s)
- Meng Yuan
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Guotao Chen
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Yibo Xiao
- Protoga Biotechnology Co., Ltd., Shenzhen 518000, China; Microalgae Biosynthesis R&D Center, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Yujiao Qu
- Protoga Biotechnology Co., Ltd., Shenzhen 518000, China; Microalgae Biosynthesis R&D Center, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Yuan Ren
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China; The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou 510006, China.
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Singh S, Singh S, Trivedi M, Dwivedi M. An insight into MDR Acinetobacter baumannii infection and its pathogenesis: Potential therapeutic targets and challenges. Microb Pathog 2024; 192:106674. [PMID: 38714263 DOI: 10.1016/j.micpath.2024.106674] [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: 10/19/2023] [Revised: 04/22/2024] [Accepted: 05/01/2024] [Indexed: 05/09/2024]
Abstract
Acinetobacter baumannii is observed as a common species of Gram-negative bacteria that exist in soil and water. Despite being accepted as a typical component of human skin flora, it has become an important opportunistic pathogen, especially in healthcare settings. The pathogenicity of A. baumannii is attributed to its virulence factors, which include adhesins, pili, lipopolysaccharides, outer membrane proteins, iron uptake systems, autotransporter, secretion systems, phospholipases etc. These elements provide the bacterium the ability to cling to and penetrate host cells, get past the host immune system, and destroy tissue. Its infection is a major contributor to human pathophysiological conditions including pneumonia, bloodstream infections, urinary tract infections, and surgical site infections. It is challenging to treat infections brought on by this pathogen since this bacterium has evolved to withstand numerous drugs and further emergence of drug-resistant A. baumannii results in higher rates of morbidity and mortality. The long-term survival of this bacterium on surfaces of medical supplies and hospital furniture facilitates its frequent spread in humans from one habitat to another. There is a need for urgent investigations to find effective drug targets for A. baumannii as well as designing novel drugs to reduce the survival and spread of infection. In the current review, we represent the specific features, pathogenesis, and molecular intricacies of crucial drug targets of A. baumannii. This would also assist in proposing strategies and alternative therapies for the prevention and treatment of A. baumannii infections and their spread.
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Affiliation(s)
- Sukriti Singh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Sushmita Singh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Mala Trivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Manish Dwivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India; Research Cell, Amity University Uttar Pradesh, Lucknow, 226028, India.
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Mohseni Sani N, Talaee M, Akbari A, Ashoori F, Zamani J, Kermani AA, Shahbani Zahiri H, Presley J, Vali H, Akbari Noghabi K. Unveiling the structure-emulsifying function relationship of truncated recombinant forms of the SA01-OmpA protein opens up a new vista in bioemulsifiers. Microbiol Spectr 2024; 12:e0346523. [PMID: 38206002 PMCID: PMC10846152 DOI: 10.1128/spectrum.03465-23] [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: 10/04/2023] [Accepted: 12/03/2023] [Indexed: 01/12/2024] Open
Abstract
The emulsifying ability of SA01-OmpA (outer membrane protein A from Acinetobacter sp. SA01) was found to be constrained by challenges like low production efficiency and high costs associated with protein recovery from E. coli inclusion bodies, as described in our previous study. The present study sought to benefit from the advantages of the targeted truncating of SA01-OmpA protein, taking into account the reduced propensity of protein expression as inclusion bodies and cytotoxicity. Here, the structure and activity relationship of two truncated recombinant forms of SA01-OmpA protein was unraveled through a hybrid approach based on experimental data and computational methodologies, representing an innovative bioemulsifier with advantageous emulsifying activity. The recombinant truncated SA01-OmpA variants were cloned and heterologously expressed in E. coli host cells and subsequently purified. The results showed increased emulsifying activity of N-terminally truncated SA01-OmpA (NT-OmpA) compared to full-length SA01-OmpA. Molecular dynamics (MD) simulations analysis demonstrated a direct correlation between the C-terminally truncated SA01-OmpA (CT-OmpA) and its expression as inclusion bodies. Analysis of the structure-activity relationship of truncated variants of SA01-OmpA revealed that, compared to the full-length protein, deletion of the β-barrel portion from the N-terminal of SA01-OmpA increased the emulsifying activity of NT-OmpA while lowering its expression as inclusion bodies. Contrary to the full-length protein, the N-terminally truncated SA01-OmpA was not as cytotoxic, according to the MTT assay, FCM analysis, and AO/EB staining. The findings of this extensive study advance our knowledge of SA01-OmpA at the molecular level as well as the design and development of efficient bioemulsifiers.IMPORTANCEPrevious research (Shahryari et al. 2021, mSystems 6: e01175-20) introduced and characterized the SA01-OmpA protein as a multifaceted protein with a variety of functions, including maintaining cellular homeostasis under oxidative stress conditions, biofilm formation, outer membrane vesicles (OMV) biogenesis, and beneficial emulsifying capacity. By truncating the SA01-OmpA protein, the current study presents a unique method for developing protein-type bioemulsifiers. The findings indicate that the N-terminally truncated SA01-OmpA (NT-OmpA) has the potential to fully replace full-length SA01-OmpA as a novel bioemulsifier with significant emulsifying activity. This study opens up a new frontier in bioemulsifiers, shedding light on a possible relationship between the structure and activity of SA01-OmpA truncated forms.
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Affiliation(s)
- Naeema Mohseni Sani
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Mahbubeh Talaee
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Ali Akbari
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Faranak Ashoori
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Javad Zamani
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Ali A. Kermani
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Hossein Shahbani Zahiri
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - John Presley
- Department of Anatomy & Cell Biology, McGill University, Montreal, Québec, Canada
| | - Hojatollah Vali
- Department of Anatomy & Cell Biology, McGill University, Montreal, Québec, Canada
| | - Kambiz Akbari Noghabi
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
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Holley CL, Dhulipala V, Maurakis SA, Greenawalt AN, Read TD, Cornelissen CN, Shafer WM. Transcriptional activation of ompA in Neisseria gonorrhoeae mediated by the XRE family member protein NceR. mBio 2023; 14:e0124423. [PMID: 37387605 PMCID: PMC10470515 DOI: 10.1128/mbio.01244-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 07/01/2023] Open
Abstract
Increasing antibiotic resistance of Neisseria gonorrhoeae, the causative agent of gonorrhea, is a growing global concern that has renewed vaccine development efforts. The gonococcal OmpA protein was previously identified as a vaccine candidate due to its surface exposure, conservation, stable expression, and involvement in host-cell interactions. We previously demonstrated that the transcription of ompA can be activated by the MisR/MisS two-component system. Interestingly, earlier work suggested that the availability of free iron also influences ompA expression, which we confirmed in this study. In the present study, we found that iron regulation of ompA was independent of MisR and searched for additional regulators. A DNA pull-down assay with the ompA promoter from gonococcal lysates obtained from bacteria grown in the presence or absence of iron identified an XRE (Xenobiotic Response Element) family member protein encoded by NGO1982. We found that an NGO1982 null mutant of N. gonorrhoeae strain FA19 displayed a reduced level of ompA expression compared to the wild-type (WT) parent strain. Given this regulation, and the capacity of this XRE-like protein to regulate a gene involved in peptidoglycan biosynthesis (ltgA), along with its presence in other Neisseria sp., we termed the NGO1982-encoded protein as NceR (Neisseria cell envelope regulator). Critically, results from DNA-binding studies indicated that NceR regulates ompA through a direct mechanism. Thus, ompA expression is subject to both iron-dependent (NceR) and -independent (MisR/MisS) pathways. Hence, levels of the vaccine antigen candidate OmpA in circulating gonococcal strains could be influenced by transcriptional regulatory systems and the availability of iron. IMPORTANCE Herein, we report that the gene encoding a conserved gonococcal surface-exposed vaccine candidate (OmpA) is activated by a heretofore undescribed XRE family transcription factor, which we term NceR. We report that NceR regulation of ompA expression in N. gonorrhoeae is mediated by an iron-dependent mechanism, while the previously described MisR regulatory system is iron-independent. Our study highlights the importance of defining the complexity of coordinated genetic and physiologic systems that regulate genes encoding vaccine candidates to better understand their availability during infection.
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Affiliation(s)
- Concerta L. Holley
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Vijaya Dhulipala
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Stavaros A. Maurakis
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, USA
| | | | - Timothy D. Read
- Department of Medicine (Division of Infectious Diseases), Emory University School of Medicine, Atlanta, Georgia, USA
- The Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - William M. Shafer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Medicine (Division of Infectious Diseases), Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Bacterial Pathogenesis, Veterans Affairs Medical Center, Decatur, Georgia, USA
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Schmitt BL, Leal BF, Leyser M, de Barros MP, Trentin DS, Ferreira CAS, de Oliveira SD. Increased ompW and ompA expression and higher virulence of Acinetobacter baumannii persister cells. BMC Microbiol 2023; 23:157. [PMID: 37246220 DOI: 10.1186/s12866-023-02904-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 05/19/2023] [Indexed: 05/30/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii is one of the main causes of healthcare-associated infections that threaten public health, and carbapenems, such as meropenem, have been a therapeutic option for these infections. Therapeutic failure is mainly due to the antimicrobial resistance of A. baumannii, as well as the presence of persister cells. Persisters constitute a fraction of the bacterial population that present a transient phenotype capable of tolerating supra-lethal concentrations of antibiotics. Some proteins have been suggested to be involved in the onset and/or maintenance of this phenotype. Thus, we investigated the mRNA levels of the adeB (AdeABC efflux pump component), ompA, and ompW (outer membrane proteins) in A. baumannii cells before and after exposure to meropenem. RESULTS We found a significant increase (p-value < 0.05) in the expression of ompA (> 5.5-fold) and ompW (> 10.5-fold) in persisters. However, adeB did not show significantly different expression levels when comparing treated and untreated cells. Therefore, we suggest that these outer membrane proteins, especially OmpW, could be part of the mechanism of A. baumannii persisters to deal with the presence of high doses of meropenem. We also observed in the Galleria mellonella larvae model that persister cells are more virulent than regular ones, as evidenced by their LD50 values. CONCLUSIONS Taken together, these data contribute to the understanding of the phenotypic features of A. baumannii persisters and their relation to virulence, as well as highlight OmpW and OmpA as potential targets for drug development against A. baumannii persisters.
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Affiliation(s)
- Brenda Landvoigt Schmitt
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - Bruna Ferreira Leal
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - Mariana Leyser
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - Muriel Primon de Barros
- Laboratório de Bacteriologia e Modelos Experimentais Alternativos, Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre, UFCSPA, R. Sarmento Leite, 245, Porto Alegre, RS, 90050-170, Brazil
| | - Danielle Silva Trentin
- Laboratório de Bacteriologia e Modelos Experimentais Alternativos, Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre, UFCSPA, R. Sarmento Leite, 245, Porto Alegre, RS, 90050-170, Brazil
| | - Carlos Alexandre Sanchez Ferreira
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
| | - Sílvia Dias de Oliveira
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
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Li M, Yu J, Cao L, Yin Y, Su Z, Chen S, Li G, Ma T. Facultative anaerobic conversion of lignocellulose biomass to new bioemulsifier by thermophilic Geobacillus thermodenitrificans NG80-2. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130210. [PMID: 36308930 DOI: 10.1016/j.jhazmat.2022.130210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/06/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Heavy oil has hindered crude oil exploitation and pollution remediation due to its high density and viscosity. Bioemulsifiers efficiently facilitate the formation and stabilization of oil-in-water emulsions in low concentrations thus eliminating the above bottleneck. Despite their potential benefits, various obstacles had still impeded the practical applications of bioemulsifiers, including high purification costs and poor adaptability to extreme environments such as high temperature and oxygen deficiency. Herein, thermophilic facultative anaerobic Geobacillus thermodenitrificans NG80-2 was proved capable of emulsifying heavy oils and reducing their viscosity. An exocelluar bioemulsifier could be produced by NG80-2 using low-cost lignocellulose components as carbon sources even under anaerobic condition. The purified bioemulsifier was proved to be polysaccharide-protein complexes, and both components contributed to its emulsifying capability. In addition, it displayed excellent stress tolerance over wide ranges of temperatures, salinities, and pHs. Meanwhile, the bioemulsifier significantly improved oil recovery and degradation efficiency. An eps gene cluster for polysaccharide biosynthesis and genes for the covalently bonded proteins was further certificated. Therefore, the bioemulsifier produced by G. thermodenitrificans NG80-2 has immense potential for applications in bioremediation and EOR, and its biosynthesis pathway revealed here provides a theoretical basis for increasing bioemulsifier output.
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Affiliation(s)
- Mingchang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jiaqi Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Lu Cao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yujun Yin
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhaoying Su
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shuai Chen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Guoqiang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China.
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Shahryari S, Mohammadnejad P, Noghabi KA. Screening of anti- Acinetobacter baumannii phytochemicals, based on the potential inhibitory effect on OmpA and OmpW functions. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201652. [PMID: 34457318 PMCID: PMC8371366 DOI: 10.1098/rsos.201652] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/27/2021] [Indexed: 05/08/2023]
Abstract
Therapeutic options including last-line or combined antibiotic therapies for multi-drug-resistant strains of Acinetobacter baumannii are ineffective. The outer membrane protein A (OmpA) and outer membrane protein W (OmpW) are two porins known for their different cellular functions. Identification of natural compounds with the potentials to block these putative porins can attenuate the growth of the bacteria and control the relating diseases. The current work aimed to screen a library of 384 phytochemicals according to their potentials to be used as a drug, and potentials to inhibit the function of OmpA and OmpW in A. baumannii. The phytocompounds were initially screened based on their physico-chemical, absorption, distribution, metabolism, excretion and toxicity (ADMET) drug-like properties. Afterwards, the selected ligands were subjected to standard docking calculations against the predicted three-dimensional structure of OmpA and OmpW in A. baumannii. We identified three phytochemicals (isosakuranetin, aloe-emodin and pinocembrin) possessing appreciable binding affinity towards the selected binding pocket of OmpA and OmpW. Molecular dynamics simulation analysis confirmed the stability of the complexes. Among them, isosakuranetin was suggested as the best phytocompound for further in vitro and in vivo study.
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Affiliation(s)
- Shahab Shahryari
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran
| | - Parvin Mohammadnejad
- Division of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14965/161, Tehran, Iran
| | - Kambiz Akbari Noghabi
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran
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Roy R, You RI, Chang CH, Yang CY, Lin NT. Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii. Microorganisms 2021; 9:microorganisms9061336. [PMID: 34203028 PMCID: PMC8234194 DOI: 10.3390/microorganisms9061336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.
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Affiliation(s)
- Rakesh Roy
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Ren-In You
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Chan-Hua Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
| | - Nien-Tsung Lin
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
- Department of Microbiology, School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
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9
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Scheller D, Twittenhoff C, Becker F, Holler M, Narberhaus F. OmpA, a Common Virulence Factor, Is Under RNA Thermometer Control in Yersinia pseudotuberculosis. Front Microbiol 2021; 12:687260. [PMID: 34220779 PMCID: PMC8245352 DOI: 10.3389/fmicb.2021.687260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/21/2021] [Indexed: 11/13/2022] Open
Abstract
The outer membrane protein OmpA is a virulence factor in many mammalian pathogens. In previous global RNA structure probing studies, we found evidence for a temperature-modulated RNA structure in the 5'-untranslated region (5'-UTR) of the Yersinia pseudotuberculosis ompA transcript suggesting that opening of the structure at host-body temperature might relieve translational repression. Here, we support this hypothesis by quantitative reverse transcription PCR, translational reporter gene fusions, enzymatic RNA structure probing, and toeprinting assays. While ompA transcript levels decreased at 37°C compared to 25°C, translation of the transcript increased with increasing temperature. Biochemical experiments show that this is due to melting of the RNA structure, which permits ribosome binding to the 5'-UTR. A point mutation that locks the RNA structure in a closed conformation prevents translation by impairing ribosome access. Our findings add another common virulence factor to the growing list of pathogen-associated genes that are under RNA thermometer control.
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Affiliation(s)
- Daniel Scheller
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | | | - Franziska Becker
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Marcel Holler
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Franz Narberhaus
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
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