1
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Zhou Z, Li Z, Li Z. Exploring the molecular mechanisms of Lrp/AsnC-type transcription regulator DecR, an L-cysteine-responsive feast/famine regulatory protein. Int J Biol Macromol 2024; 270:132519. [PMID: 38768919 DOI: 10.1016/j.ijbiomac.2024.132519] [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: 03/28/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
The Lrp/AsnC family of transcriptional regulators is commonly found in prokaryotes and is associated with the regulation of amino acid metabolism. However, it remains unclear how the L-cysteine-responsive Lrp/AsnC family regulator perceives and responds to L-cysteine. Here, we try to elucidate the molecular mechanism of the L-cysteine-responsive transcriptional regulator. Through 5'RACE and EMSA, we discovered a 15 bp incompletely complementary pair palindromic sequence essential for DecR binding, which differed slightly from the binding sequence of other Lrp/AsnC transcription regulators. Using alanine scanning, we identified the L-cysteine binding site on DecR and found that different Lrp/AsnC regulators adjust their binding pocket's side-chain residues to accommodate their specific effector. MD simulations were then conducted to explore how ligand binding influences the allosteric behavior of the protein. PCA and in silico docking revealed that ligand binding induced perturbations in the linker region, triggering conformational alterations and leading to the relocalization of the DNA-binding domains, enabling the embedding of the DNA-binding region of DecR into the DNA molecule, thereby enhancing DNA-binding affinity. Our findings can broaden the understanding of the recognition and regulatory mechanisms of the Lrp/AsnC-type transcription factors, providing a theoretical basis for further investigating the molecular mechanisms of other transcription factors.
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Affiliation(s)
- Zhiyou Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zonglin Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Zhimin Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Meilong Road, Shanghai 200237, China.
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2
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Jian P, Liu J, Li L, Song Q, Zhang D, Zhang S, Chai C, Zhao H, Zhao G, Zhu H, Qiao J. AcrR1, a novel TetR/AcrR family repressor, mediates acid and antibiotic resistance and nisin biosynthesis in Lactococcus lactis F44. J Dairy Sci 2024:S0022-0302(24)00806-3. [PMID: 38762103 DOI: 10.3168/jds.2024-24754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/31/2024] [Indexed: 05/20/2024]
Abstract
Lactococcus lactis, widely used in the manufacture of dairy products, encounters various environmental stresses both in natural habitats and during industrial processes. It has evolved intricate machinery of stress sensing and defense to survive harsh stress conditions. Here, we identified a novel TetR/AcrR family transcription regulator, designated AcrR1, to be a repressor for acid and antibiotic tolerance that was derepressed in the presence of vancomycin or under acid stress. The survival rates of acrR1 deletion strain ΔAcrR1 under acid and vancomycin stresses were about 28.7-fold (pH 3.0, HCl), 8.57-fold (pH 4.0, lactic acid) and 2.73-fold (300 ng/mL vancomycin) as that of original strain F44. We also demonstrated that ΔAcrR1 was better able to maintain intracellular pH homeostasis and had a lower affinity to vancomycin. No evident effects of AcrR1 deletion on the growth and morphology of strain F44 were observed. Subsequently, we characterized that the transcription level of genes associated with amino acids biosynthesis, carbohydrate transport and metabolism, multiple drug resistance and DNA repair proteins significantly upregulated in ΔAcrR1 using transcriptome analysis and quantitative reverse transcription-PCR (qRT-PCR) assays. Additionally, AcrR1 could repress the transcription of nisin post-translational modification gene, nisC, leading to a 16.3% increase in nisin yield after AcrR1 deletion. Our results not only refined the knowledge of the regulatory mechanism of TetR/AcrR family regulator in L. lactis, but presented a potential strategy to enhance industrial production of nisin.
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Affiliation(s)
- Pingqiu Jian
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China
| | - Jiaheng Liu
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China.
| | - Li Li
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Qianqian Song
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Di Zhang
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China
| | - Shenyi Zhang
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China
| | - Chaofan Chai
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China
| | - Hui Zhao
- Department of Pharmaceutical and Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, China
| | - Guangrong Zhao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Hongji Zhu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
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3
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Han F, Li H, Lyu E, Zhang Q, Gai H, Xu Y, Bai X, He X, Khan AQ, Li X, Xie F, Li F, Fang X, Wei M. Soybean-mediated suppression of BjaI/BjaR 1 quorum sensing in Bradyrhizobium diazoefficiens impacts symbiotic nitrogen fixation. Appl Environ Microbiol 2024; 90:e0137423. [PMID: 38251894 PMCID: PMC10880635 DOI: 10.1128/aem.01374-23] [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: 08/09/2023] [Accepted: 11/23/2023] [Indexed: 01/23/2024] Open
Abstract
The acyl-homoserine lactones (AHLs)-mediated LuxI/LuxR quorum sensing (QS) system orchestrates diverse bacterial behaviors in response to changes in population density. The role of the BjaI/BjaR1 QS system in Bradyrhizobium diazoefficiens USDA 110, which shares homology with LuxI/LuxR, remains elusive during symbiotic interaction with soybean. Here this genetic system in wild-type (WT) bacteria residing inside nodules exhibited significantly reduced activity compared to free-living cells, potentially attributed to soybean-mediated suppression. The deletion mutant strain ΔbjaR1 showed significantly enhanced nodulation induction and nitrogen fixation ability. Nevertheless, its ultimate symbiotic outcome (plant dry weight) in soybeans was compromised. Furthermore, comparative analysis of the transcriptome, proteome, and promoter activity revealed that the inactivation of BjaR1 systematically activated and inhibited genomic modules associated with nodulation and nitrogen metabolism. The former appeared to be linked to a significant decrease in the expression of NodD2, a key cell-density-dependent repressor of nodulation genes, while the latter conferred bacterial growth and nitrogen fixation insensitivity to environmental nitrogen. In addition, BjaR1 exerted a positive influence on the transcription of multiple genes involved in a so-called central intermediate metabolism within the nodule. In conclusion, our findings highlight the crucial role of the BjaI/BjaR1 QS circuit in positively regulating bacterial nitrogen metabolism and emphasize the significance of the soybean-mediated suppression of this genetic system for promoting efficient symbiotic nitrogen fixation by B. diazoefficiens.IMPORTANCEThe present study demonstrates, for the first time, that the BjaI/BjaR1 QS system of Bradyrhizobium diazoefficiens has a significant impact on its nodulation and nitrogen fixation capability in soybean by positively regulating NodD2 expression and bacterial nitrogen metabolism. Moreover, it provides novel insights into the importance of suppressing the activity of this QS circuit by the soybean host plant in establishing an efficient mutual relationship between the two symbiotic partners. This research expands our understanding of legumes' role in modulating symbiotic nitrogen fixation through rhizobial QS-mediated metabolic functioning, thereby deepening our comprehension of symbiotic coevolution theory. In addition, these findings may hold great promise for developing quorum quenching technology in agriculture.
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Affiliation(s)
- Fang Han
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Huiquan Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Ermeng Lyu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Qianqian Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Haoyu Gai
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Yunfang Xu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xuemei Bai
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xueqian He
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Abdul Qadir Khan
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xiaolin Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Fengmin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xiangwen Fang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Min Wei
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
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Zhang SP, Ye YP, Hou J, Ye ZR, Wang ZS, Yu XQ, Guo DD, Wang Y, He YX. Antitoxin MqsA decreases antibiotic susceptibility through the global regulator AgtR in Pseudomonas fluorescens. Antimicrob Agents Chemother 2023; 67:e0081223. [PMID: 37877694 PMCID: PMC10649091 DOI: 10.1128/aac.00812-23] [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: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/26/2023] Open
Abstract
Type II toxin-antitoxin systems are highly prevalent in bacterial genomes and play crucial roles in the general stress response. Previously, we demonstrated that the type II antitoxin PfMqsA regulates biofilm formation through the global regulator AgtR in Pseudomonas fluorescens. Here, we found that both the C-terminal DNA-binding domain of PfMqsA and AgtR are involved in bacterial antibiotic susceptibility. Electrophoretic mobility shift assay (EMSA) analyses revealed that AgtR, rather than PfMqsA, binds to the intergenic region of emhABC-emhR, in which emhABC encodes an resistance-nodulation-cell division efflux pump and emhR encodes a repressor. Through quantitative real-time reverse-transcription PCR and EMSA analysis, we showed that AgtR directly activates the expression of the emhR by binding to the DNA motif [5´-CTAAGAAATATACTTAC-3´], leading to repression of the emhABC. Furthermore, we demonstrated that PfMqsA modulates the expression of EmhABC and EmhR. These findings enhance our understanding of the mechanism by which antitoxin PfMqsA contributes to antibiotic susceptibility.
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Affiliation(s)
- Si-Ping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yi-Ping Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Jun Hou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zi-Rui Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zhi-Song Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Xiao-Quan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Ding-Ding Guo
- School of Pharmacy, Lanzhou University, Lanzhou, Gansu, China
| | - Yong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
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5
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Patil RS, Sharma S, Bhaskarwar AV, Nambiar S, Bhat NA, Koppolu MK, Bhukya H. TetR and OmpR family regulators in natural product biosynthesis and resistance. Proteins 2023. [PMID: 37874037 DOI: 10.1002/prot.26621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications.
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Affiliation(s)
- Rachit S Patil
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Siddhant Sharma
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Aditya V Bhaskarwar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Souparnika Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Niharika A Bhat
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Mani Kanta Koppolu
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Hussain Bhukya
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
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6
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Cui B, Guo Q, Li X, Song S, Wang M, Wang G, Yan A, Zhou J, Deng Y. A response regulator controls Acinetobacter baumannii virulence by acting as an indole receptor. PNAS NEXUS 2023; 2:pgad274. [PMID: 37649583 PMCID: PMC10465187 DOI: 10.1093/pnasnexus/pgad274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 08/18/2023] [Indexed: 09/01/2023]
Abstract
Indole is an important signal employed by many bacteria to modulate intraspecies signaling and interspecies or interkingdom communication. Our recent study revealed that indole plays a key role in regulating the physiology and virulence of Acinetobacter baumannii. However, it is not clear how A. baumannii perceives and responds to the indole signal in modulating biological functions. Here, we report that indole controls the physiology and virulence of A. baumannii through a previously uncharacterized response regulator designated as AbiR (A1S_1394), which contains a cheY-homologous receiver (REC) domain and a helix-turn-helix (HTH) DNA-binding domain. AbiR controls the same biological functions as the indole signal, and indole-deficient mutant phenotypes were rescued by in trans expression of AbiR. Intriguingly, unlike other response regulators that commonly interact with signal ligands through the REC domain, AbiR binds to indole with a high affinity via an unusual binding region, which is located between its REC and HTH domains. This interaction substantially enhances the activity of AbiR in promoter binding and in modulation of target gene expression. Taken together, our results present a widely conserved regulator that controls bacterial physiology and virulence by sensing the indole signal in a unique mechanism.
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Affiliation(s)
- Binbin Cui
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Quan Guo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Xia Li
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Shihao Song
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
- School of Pharmaceutical Sciences, Hainan University, Renmin Avenue, Meilan District, Haikou 570228, China
| | - Mingfang Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Gerun Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
| | - Aixin Yan
- School of Biological Sciences, The University of Hong Kong, University Road, Pok Fu Lam Estate, Central and Western District, Hong Kong 999077, China
| | - Jianuan Zhou
- Integrative Microbiology Research Center, South China Agricultural University, Wushan Road, Wushan Street, Tianhe District Guangzhou 510642, China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Gongchang Road, Guangming District, Shenzhen 518107, China
- School of Pharmaceutical Sciences, Hainan University, Renmin Avenue, Meilan District, Haikou 570228, China
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7
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Jayaraman S, Adhilaxmi Kannan M, Rajendhran N, John GJ, Ramasamy T. Indole-3-acetic acid impacts biofilm formation and virulence production of Pseudomonas aeruginosa. BIOFOULING 2023; 39:800-815. [PMID: 37853689 DOI: 10.1080/08927014.2023.2269537] [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: 01/03/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Abstract
Bacterial pathogenesis involves complex mechanisms contributing to virulence and persistence of infections. Understanding the multifactorial nature of bacterial infections is crucial for developing effective interventions. The present study investigated the efficacy of indole-3-acetic acid (IAA) against Pseudomonas aeruginosa with various end points including antibacterial activity, minimum inhibitory concentration (MIC), virulence factor production, biofilm inhibition, bacterial cell detachment, and viability assays. Results showed significant biofilm inhibition, bacterial cell detachment, and modest effects on bacterial viability. Microscopic analysis confirmed the disintegrated biofilm matrix, supporting the inhibitory effect of IAA. Additionally, molecular docking studies revealed potential mechanisms of action through active bond interactions between IAA and virulence proteins. These findings highlight IAA as an effective antibiofilm agent against P. aeruginosa.
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Affiliation(s)
- Sudharshini Jayaraman
- Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Monika Adhilaxmi Kannan
- Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Nandhini Rajendhran
- Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Georrge J John
- Department of Bioinformatics, University of North Bengal, Raja Rammohunpur, West Bengal, India
| | - Thirumurugan Ramasamy
- Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
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8
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De Gaetano GV, Lentini G, Famà A, Coppolino F, Beninati C. Antimicrobial Resistance: Two-Component Regulatory Systems and Multidrug Efflux Pumps. Antibiotics (Basel) 2023; 12:965. [PMID: 37370284 DOI: 10.3390/antibiotics12060965] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The number of multidrug-resistant bacteria is rapidly spreading worldwide. Among the various mechanisms determining resistance to antimicrobial agents, multidrug efflux pumps play a noteworthy role because they export extraneous and noxious substrates from the inside to the outside environment of the bacterial cell contributing to multidrug resistance (MDR) and, consequently, to the failure of anti-infective therapies. The expression of multidrug efflux pumps can be under the control of transcriptional regulators and two-component systems (TCS). TCS are a major mechanism by which microorganisms sense and reply to external and/or intramembrane stimuli by coordinating the expression of genes involved not only in pathogenic pathways but also in antibiotic resistance. In this review, we describe the influence of TCS on multidrug efflux pump expression and activity in some Gram-negative and Gram-positive bacteria. Taking into account the strict correlation between TCS and multidrug efflux pumps, the development of drugs targeting TCS, alone or together with already discovered efflux pump inhibitors, may represent a beneficial strategy to contribute to the fight against growing antibiotic resistance.
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Affiliation(s)
| | - Germana Lentini
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Agata Famà
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Francesco Coppolino
- Department of Biomedical, Dental and Imaging Sciences, University of Messina, 98124 Messina, Italy
| | - Concetta Beninati
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
- Scylla Biotech Srl, 98124 Messina, Italy
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9
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Krell T, Gavira JA, Roca A, Matilla MA. The emerging role of auxins as bacterial signal molecules: Potential biotechnological applications. Microb Biotechnol 2023. [PMID: 37466451 PMCID: PMC10364314 DOI: 10.1111/1751-7915.14235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 02/01/2023] [Indexed: 07/20/2023] Open
Abstract
Microorganisms are exposed in their natural niches to a wide diversity of signal molecules. Specific detection of these signals results in alterations in microbial metabolism and physiology. Auxins like indole-3-acetic acid are key phytohormones that regulate plant growth and development. Nonetheless, auxin biosynthesis is not restricted to plants but is ubiquitous in all kingdoms of life. This wide phylogenetic distribution of auxins production, together with the diversity of regulated cellular processes, have made auxins key intra- and inter-kingdom signal molecules in life modulating, for example microbial physiology, metabolism and virulence. Despite their increasing importance as global signal molecules, the mechanisms by which auxins perform their regulatory functions in microorganisms are largely unknown. In this article, we outline recent research that has advanced our knowledge of the mechanisms of bacterial auxin perception. We also highlight the potential applications of this research in aspects such as antibiotic production, biosensor design, plant microbiome engineering and antivirulence therapies.
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Affiliation(s)
- Tino Krell
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - José A Gavira
- Laboratory of Crystallographic Studies, IACT (CSIC-UGR), Armilla, Spain
| | - Amalia Roca
- Department of Microbiology, Facultad de Farmacia, Universidad de Granada, Granada, Spain
| | - Miguel A Matilla
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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10
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Shi X, Zarkan A. Bacterial survivors: evaluating the mechanisms of antibiotic persistence. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748698 DOI: 10.1099/mic.0.001266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacteria withstand antibiotic onslaughts by employing a variety of strategies, one of which is persistence. Persistence occurs in a bacterial population where a subpopulation of cells (persisters) survives antibiotic treatment and can regrow in a drug-free environment. Persisters may cause the recalcitrance of infectious diseases and can be a stepping stone to antibiotic resistance, so understanding persistence mechanisms is critical for therapeutic applications. However, current understanding of persistence is pervaded by paradoxes that stymie research progress, and many aspects of this cellular state remain elusive. In this review, we summarize the putative persister mechanisms, including toxin-antitoxin modules, quorum sensing, indole signalling and epigenetics, as well as the reasons behind the inconsistent body of evidence. We highlight present limitations in the field and underscore a clinical context that is frequently neglected, in the hope of supporting future researchers in examining clinically important persister mechanisms.
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Affiliation(s)
- Xiaoyi Shi
- Cambridge Centre for International Research, Cambridge CB4 0PZ, UK
| | - Ashraf Zarkan
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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11
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Cui B, Chen X, Guo Q, Song S, Wang M, Liu J, Deng Y. The Cell-Cell Communication Signal Indole Controls the Physiology and Interspecies Communication of Acinetobacter baumannii. Microbiol Spectr 2022; 10:e0102722. [PMID: 35862954 PMCID: PMC9431217 DOI: 10.1128/spectrum.01027-22] [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: 03/21/2022] [Accepted: 06/16/2022] [Indexed: 11/20/2022] Open
Abstract
Many bacteria utilize quorum sensing (QS) to control group behavior in a cell density-dependent manner. Previous studies have demonstrated that Acinetobacter baumannii employs an N-acyl-L-homoserine lactone (AHL)-based QS system to control biological functions and virulence. Here, we report that indole controls biological functions, virulence and AHL signal production in A. baumannii. The biosynthesis of indole is performed by A1S_3160 (AbiS, Acinetobacter baumannii indole synthase), which is a novel indole synthase annotated as an alpha/beta hydrolase in A. baumannii. Heterologous expression of AbiS in an Escherichia coli indole-deficient mutant also rescued the production of indole by using a distinct biosynthetic pathway from the tryptophanase TnaA, which produces indole directly from tryptophan in E. coli. Moreover, we revealed that indole from A. baumannii reduced the competitive fitness of Pseudomonas aeruginosa by inhibiting its QS systems and type III secretion system (T3SS). As A. baumannii and P. aeruginosa usually coexist in human lungs, our results suggest the crucial roles of indole in both the bacterial physiology and interspecies communication. IMPORTANCE Acinetobacter baumannii is an important human opportunistic pathogen that usually causes high morbidity and mortality. It employs the N-acyl-L-homoserine lactone (AHL)-type quorum sensing (QS) system, AbaI/AbaR, to regulate biological functions and virulence. In this study, we found that A. baumannii utilizes another QS signal, indole, to modulate biological functions and virulence. It was further revealed that indole positively controls the production of AHL signals by regulating abaI expression at the transcriptional levels. Furthermore, indole represses the QS systems and type III secretion system (T3SS) of P. aeruginosa and enhances the competitive ability of A. baumannii. Together, our work describes a QS signaling network where a pathogen uses to control the bacterial physiology and pathogenesis, and the competitive ability in microbial community.
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Affiliation(s)
- Binbin Cui
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Xiayu Chen
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Quan Guo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Shihao Song
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Mingfang Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Jingyun Liu
- Department of Stomatology, Zhengzhou Shuqing Medical College, Zhenzhou, China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
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Song Q, Wu H, Zhang P, Tian K, Zhu H, Qiao J. LssR plays a positive regulatory role in acid and nisin tolerance response of Lactococcus lactis. J Dairy Sci 2022; 105:6483-6498. [PMID: 35840402 DOI: 10.3168/jds.2022-21842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/14/2022] [Indexed: 11/19/2022]
Abstract
In Lactococcus lactis, different regulation mechanisms can be activated to overcome the effects of adverse environmental stresses. Here, a TetR family regulator LssR was demonstrated as a positive regulator in the activation of the mechanisms involved in acid and nisin tolerance of L. lactis. The deletion of lssR led to the reduction of tolerance of L. lactis NZ9000 to nisin and acid stress, and the survival rates of NZ9000 under nisin and acid stress were roughly 20-fold, 10-fold (pH 3.0, hydrochloric acid), and 8.9-fold (pH 4.0, lactic acid) of the lssR mutant NZΔlssR, respectively. Moreover, the lssR mutant NZΔlssR also displayed a lower intracellular pH stability and a changed cell surface morphology. Subsequently, transcriptome analysis revealed that genes related to the arginine deiminase pathway, the surface polysaccharides biosynthesis, carbohydrates transport and metabolism, multidrug resistance, cell repair proteins and chaperones were predominantly down transcribed in NZΔlssR. The transcript levels of the arginine deiminase pathway and the surface polysaccharides biosynthesis-associated genes under acid and nisin stresses were compared between the wild type NZ9000 and NZΔlssR using real-time fluorescence quantitative PCR. It revealed that the arginine deiminase pathway genes (arcD1C1C2T) and the surface polysaccharides biosynthesis genes (cgT, gmhB, gmhA, hddA, tagH and tarS) were proposed to be the main regulatory mechanisms of LssR in response to the acid and nisin stresses. Overall, the important role of LssR in the acid and nisin stresses response was demonstrated and the putative regulation mechanism of LssR was revealed.
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Affiliation(s)
- Qianqian Song
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hao Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, China
| | - Peng Zhang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Kairen Tian
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hongji Zhu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China.
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The Two-Component System RstA/RstB Regulates Expression of Multiple Efflux Pumps and Influences Anaerobic Nitrate Respiration in Pseudomonas fluorescens. mSystems 2021; 6:e0091121. [PMID: 34726491 PMCID: PMC8562477 DOI: 10.1128/msystems.00911-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Multidrug resistance (MDR) efflux pumps are involved in bacterial intrinsic resistance to multiple antimicrobials. Expression of MDR efflux pumps can be either constitutive or transiently induced by various environmental signals, which are typically perceived by bacterial two-component systems (TCSs) and relayed to the bacterial nucleoid, where gene expression is modulated for niche adaptation. Here, we demonstrate that RstA/RstB, a TCS previously shown to control acid-induced and biofilm-related genes in Escherichiacoli, confers resistance to multiple antibiotics in Pseudomonas fluorescens by directly regulating the MDR efflux pumps EmhABC and MexCD-OprJ. Moreover, we show that phosphorylation of the conserved Asp52 residue in RstA greatly enhances RstA-DNA interaction, and regulation of the multidrug resistance by RstA/RstB is dependent on the phosphorylation of the RstA Asp52 residue by RstB. Proteome analysis reveals RstA/RstB also positively regulates the efflux pump MexEF-OprN and enzymes involved in anaerobic nitrate respiration and pyoverdine biosynthesis. Our results suggest that, by coupling the expression of multiple efflux pumps and anaerobic nitrate respiration, RstA/RstB could play a role in defense against nitrosative stress caused by anaerobic nitrate respiration. IMPORTANCE Microenvironmental hypoxia typically increases bacterial multidrug resistance by elevating expression of multidrug efflux pumps, but the precise mechanism is currently not well understood. Here, we showed that the two-component system RstA/RstB not only positively regulated expression of several efflux pumps involved in multidrug resistance, but also promoted expression of enzymes involved in anaerobic nitrate respiration and pyoverdine biosynthesis. These results suggested that, by upregulating expression of efflux pumps and pyoverdine biosynthesis-related enzymes, RstA/RstB could play a role in promoting bacterial tolerance to hypoxia by providing protection against nitrosative stress.
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Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000. J Bacteriol 2021; 204:e0038021. [PMID: 34662236 DOI: 10.1128/jb.00380-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.
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Matilla MA, Velando F, Martín-Mora D, Monteagudo-Cascales E, Krell T. A catalogue of signal molecules that interact with sensor kinases, chemoreceptors and transcriptional regulators. FEMS Microbiol Rev 2021; 46:6356564. [PMID: 34424339 DOI: 10.1093/femsre/fuab043] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/10/2021] [Indexed: 12/12/2022] Open
Abstract
Bacteria have evolved many different signal transduction systems that sense signals and generate a variety of responses. Generally, most abundant are transcriptional regulators, sensor histidine kinases and chemoreceptors. Typically, these systems recognize their signal molecules with dedicated ligand-binding domains (LBDs), which, in turn, generate a molecular stimulus that modulates the activity of the output module. There are an enormous number of different LBDs that recognize a similarly diverse set of signals. To give a global perspective of the signals that interact with transcriptional regulators, sensor kinases and chemoreceptors, we manually retrieved information on the protein-ligand interaction from about 1,200 publications and 3D structures. The resulting 811 proteins were classified according to the Pfam family into 127 groups. These data permit a delineation of the signal profiles of individual LBD families as well as distinguishing between families that recognize signals in a promiscuous manner and those that possess a well-defined ligand range. A major bottleneck in the field is the fact that the signal input of many signaling systems is unknown. The signal repertoire reported here will help the scientific community design experimental strategies to identify the signaling molecules for uncharacterised sensor proteins.
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Affiliation(s)
- Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Félix Velando
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Elizabet Monteagudo-Cascales
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
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