1
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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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2
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Chunxiao D, Ma F, Wu W, Li S, Yang J, Chen Z, Lian S, Qu Y. Metagenomic analysis reveals indole signaling effect on microbial community in sequencing batch reactors: Quorum sensing inhibition and antibiotic resistance enrichment. ENVIRONMENTAL RESEARCH 2023; 229:115897. [PMID: 37054839 DOI: 10.1016/j.envres.2023.115897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/09/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023]
Abstract
Indole is an essential signal molecule in microbial studies. However, its ecological role in biological wastewater treatments remains enigmatic. This study explores the links between indole and complex microbial communities using sequencing batch reactors exposed to 0, 15, and 150 mg/L indole concentrations. A concentration of 150 mg/L indole enriched indole degrader Burkholderiales, while pathogens, such as Giardia, Plasmodium, and Besnoitia were inhibited at 15 mg/L indole concentration. At the same time, indole reduced the abundance of predicted genes in the "signaling transduction mechanisms" pathway via the Non-supervised Orthologous Groups distributions analysis. Indole significantly decreased the concentration of homoserine lactones, especially C14-HSL. Furthermore, the quorum-sensing signaling acceptors containing LuxR, the dCACHE domain, and RpfC showed negative distributions with indole and indole oxygenase genes. Signaling acceptors' potential origins were mainly Burkholderiales, Actinobacteria, and Xanthomonadales. Meanwhile, concentrated indole (150 mg/L) increased the total abundance of antibiotic resistance genes by 3.52 folds, especially on aminoglycoside, multidrug, tetracycline, and sulfonamide. Based on Spearman's correlation analysis, the homoserine lactone degradation genes which were significantly impacted by indole negatively correlated with the antibiotic resistance gene abundance. This study brings new insights into the effect of indole signaling on in biological wastewater treatment plants.
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Affiliation(s)
- Dai Chunxiao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Fang Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Weize Wu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Shuzhen Li
- Aquatic Eco-Health Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Jing Yang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhuo Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Shengyang Lian
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) and Dalian POCT Laboratory, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
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3
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Wang Y, Bian Z, Wang Y. Biofilm formation and inhibition mediated by bacterial quorum sensing. Appl Microbiol Biotechnol 2022; 106:6365-6381. [DOI: 10.1007/s00253-022-12150-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022]
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4
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Hu L. Integration of multiple volatile cues into plant defense responses. THE NEW PHYTOLOGIST 2022; 233:618-623. [PMID: 34506634 DOI: 10.1111/nph.17724] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
The ability to predict future risks is essential for many organisms, including plants. Plants can gather information about potential future herbivory by detecting volatiles that are emitted by herbivore-attacked neighbors. Several individual volatiles have been identified as active danger cues. Recent work has also shown that plants may integrate multiple volatiles into their defense responses. Here, I discuss how the integration of multiple volatiles can increase the capacity of plants to predict future herbivore attack. I propose that integration of multiple volatile cues does not occur at the perception stage, but may through downstream early defense signaling and then be further consolidated by hormonal crosstalk. Exploring plant volatile cue integration can facilitate our understanding and utilization of chemical information transfer.
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Affiliation(s)
- Lingfei Hu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China
- Institute of Plant Sciences, University of Bern, Bern, 3013, Switzerland
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5
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Tong X, Wang F, Zhang H, Bai J, Dong Q, Yue P, Jiang X, Li X, Wang L, Guo J. iTRAQ-based comparative proteome analyses of different growth stages revealing the regulatory role of reactive oxygen species in the fruiting body development of Ophiocordyceps sinensis. PeerJ 2021; 9:e10940. [PMID: 33717691 PMCID: PMC7936569 DOI: 10.7717/peerj.10940] [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: 08/28/2020] [Accepted: 01/22/2021] [Indexed: 11/30/2022] Open
Abstract
In this study, using an isobaric tags for relative and absolute quantitation (iTRAQ ) approach coupled with LC-MS / MS and bioinformatics, the proteomes were analyzed for the crucial three stages covering the fruiting body development of Ophiocordyceps sinensis, including sclerotium (ST), primordium (PR) and mature fruiting body (MF), with a focus on fruiting body development-related proteins and the potential mechanisms of the development. A total of 1,875 proteins were identified. Principal Component Analysis (PCA) demonstrated that the protein patterns between PR and MF were more similar than ST. Differentially accumulated proteins (DAPs) analysis showed that there were 510, 173 and 514 DAPs in the comparisons of ST vs. PR, PR vs. MF and ST vs. MF, respectively. A total of 62 shared DAPs were identified and primarily enriched in proteins related to ‘carbon transport and mechanism’, ‘the response to oxidative stress’, ‘antioxidative activity’ and ‘translation’. KEGG and GO databases showed that the DAPs were enriched in terms of ‘primary metabolisms (amino acid/fatty acid/energy metabolism)’, ‘the response to oxidative stress’ and ‘peroxidase’. Furthermore, 34 DAPs involved in reactive oxygen species (ROS) metabolism were identified and clustered across the three stages using hierarchical clustering implemented in hCluster R package . It was suggested that their roles and the underlying mechanisms may be stage-specific. ROS may play a role in fungal pathogenicity in ST, the fruit-body initiation in PR, sexual reproduction and highland adaptation in MF. Crucial ROS-related proteins were identified, such as superoxide dismutase (SOD, T5A6F1), Nor-1 (T5AFX3), electron transport protein (T5AHD1), histidine phosphotransferase (HPt, T5A9Z5) and Glutathione peroxidase (T5A9V1). Besides, the accumulation of ROS at the three stages were assayed using 2,7-dichlorofuorescin diacetate (DCFH-DA) stanning. A much stronger ROS accumulation was detected at the stage MF, compared to the stages of PR and ST. Sections of ST and fruit-body part of MF were stained by DCFH-DA and observed under the fluorescencemicroscope, showing ROS was distributed within the conidiospore and ascus. Besides, SOD activity increased across the three stages, while CAT activity has a strong increasement in MF compared to the stages of ST and PR. It was suggested that ROS may act in gradient-dependent manner to regulate the fruiting body development. The coding region sequences of six DAPs were analyzed at mRNA level by quantitative real-time PCR (qRT-PCR). The results support the result of DAPs analysis and the proteome sequencing data. Our findings offer the perspective of proteome to understand the biology of fruiting body development and highland adaptation in O. sinensis, which would inform the big industry of this valuable fungus.
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Affiliation(s)
- Xinxin Tong
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Fang Wang
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Han Zhang
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Jing Bai
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Qiang Dong
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Pan Yue
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Xinyi Jiang
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Xinrui Li
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Li Wang
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Jinlin Guo
- Key Laboratory of Standardization of Chinese Medicine, Ministry of Education; Key Laboratory of Systematic Research, Development and Utilization of Chinese Medicine Resources in Sichuan Province-Key Laboratory Breeding Base founded by Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
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Local and Universal Action: The Paradoxes of Indole Signalling in Bacteria. Trends Microbiol 2020; 28:566-577. [PMID: 32544443 DOI: 10.1016/j.tim.2020.02.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/05/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023]
Abstract
Indole is a signalling molecule produced by many bacterial species and involved in intraspecies, interspecies, and interkingdom signalling. Despite the increasing volume of research published in this area, many aspects of indole signalling remain enigmatic. There is disagreement over the mechanism of indole import and export and no clearly defined target through which its effects are exerted. Progress is hindered further by the confused and sometimes contradictory body of indole research literature. We explore the reasons behind this lack of consistency and speculate whether the discovery of a new, pulse mode of indole signalling, together with a move away from the idea of a conventional protein target, might help to overcome these problems and enable the field to move forward.
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7
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Zheng J, Liu Q, Xia Y, Bai L, Feng Y. Pantoea agglomerans YS19 poly(A) polymerase I gene possesses the indole-sensing sequence in the promoter region. FEMS Microbiol Lett 2019; 366:5538762. [PMID: 31344226 DOI: 10.1093/femsle/fnz166] [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: 10/18/2018] [Accepted: 07/23/2019] [Indexed: 11/13/2022] Open
Abstract
Pantoea agglomerans YS19 is a predominant diazotrophic endophyte with multiple growth-promoting effects on its host plant that was isolated from rice. Indole is confirmed to induce many changes of physiological and biochemical characteristics in bacteria. Although YS19 cannot produce indole, it can sense indole in the environment and be regulated by indole. Here, using gfp as a reporter gene, we constructed a series of recombinant plasmids containing the promoter region of the poly(A) polymerase I gene (pcnB) fused with gfp, and compared the green fluorescence intensity at different concentrations of exogenous indole by a flow cytometer. In this research, we confirmed that exogenous indole significantly inhibited the expression of pcnB by its promoter; the regulation sequence sensitive to indole in the promoter region of the pcnB gene (In-pcnB) was between -129 and -88 bp. In-pcnB is widely distributed and strictly conserved in the same genus. These results suggest novel roles of In-pcnB in P. agglomerans YS19, showing its special relation to the indole regulatory pathway.
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Affiliation(s)
- Jing Zheng
- School of Life Science, Beijing Institute of Technology, 5# Zhongguancun Nandajie, Beijing 100081, People's Republic of China
| | - Qi Liu
- School of Life Science, Beijing Institute of Technology, 5# Zhongguancun Nandajie, Beijing 100081, People's Republic of China
| | - Yifan Xia
- School of Life Science, Beijing Institute of Technology, 5# Zhongguancun Nandajie, Beijing 100081, People's Republic of China
| | - Lijuan Bai
- School of Life Science, Beijing Institute of Technology, 5# Zhongguancun Nandajie, Beijing 100081, People's Republic of China
| | - Yongjun Feng
- School of Life Science, Beijing Institute of Technology, 5# Zhongguancun Nandajie, Beijing 100081, People's Republic of China
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Veselova MA, Plyuta VA, Khmel IA. Volatile Compounds of Bacterial Origin: Structure, Biosynthesis, and Biological Activity. Microbiology (Reading) 2019. [DOI: 10.1134/s0026261719030160] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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9
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Sun H, Zheng M, Song J, Huang S, Pan Y, Gong R, Lin Z. Multiple-species hormetic phenomena induced by indole: A case study on the toxicity of indole to bacteria, algae and human cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 657:46-55. [PMID: 30530218 DOI: 10.1016/j.scitotenv.2018.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 11/30/2018] [Accepted: 12/02/2018] [Indexed: 06/09/2023]
Abstract
Hormesis is a dose-response relationship phenomenon characterized by low-dose stimulation and high-dose inhibition. Although hormetic phenomena have been reported in broadly ranging biological areas, there is still no unified mechanism of hormesis. Investigating multiple-species hormesis of one compound and then exploring the possible mechanism may be an effective approach to clarify the reason for the occurrence of hormetic phenomena in a broad range of organisms. In this study, indole was selected as the test chemical due to the broad biological and hormetic effects of indole compounds. The results show that indole induces multiple-species hormetic phenomena in bacteria (Aliivibrio fischeri (A. fischeri), Escherichia coli and Bacillus subtilis), algae (Microcystis aeruginosa and Selenastrum capricornutum), and human cells (human skin fibroblasts and human cervical cancer cells). Through in-depth investigation of the time-dependent hormetic effects of indole, indole derivatives and indole's structural analogs on the bioluminescence of A. fischeri, indole ring has been identified as the potential key structure that causes indole to act on quorum sensing of A. fischeri to induce hormetic effects on the bioluminescence at lag, logarithmic, and stationary phases. Therefore, the occurrence of multiple-species hormetic phenomena is speculated to be derived from the action of indole on the cell-to-cell communication of organism cells. This paper can not only further confirm the generalizability of hormesis but also provide a reasonable explanation for hormesis, which will benefit the development of hormesis and the risk assessment of environmental pollutants.
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Affiliation(s)
- Haoyu Sun
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Min Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Jinyuan Song
- China Solid Waste and Chemical Management Technology Center, Ministry of Environmental Protection, Beijing 100029, China
| | - Shengyou Huang
- Shanghai International Studies University Bilingual School, Shanghai 200092, China
| | - Yongzheng Pan
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Ruochong Gong
- Shanghai Foreign Language Primary School Affiliated to Shanghai International Studies University, Shanghai 200092, China
| | - Zhifen Lin
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Shanghai Key Lab of Chemical Assessment and Sustainability, Shanghai, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China.
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10
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Hu L, Ye M, Erb M. Integration of two herbivore-induced plant volatiles results in synergistic effects on plant defence and resistance. PLANT, CELL & ENVIRONMENT 2019; 42:959-971. [PMID: 30195252 PMCID: PMC6392123 DOI: 10.1111/pce.13443] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/25/2018] [Accepted: 09/02/2018] [Indexed: 05/03/2023]
Abstract
Plants can use induced volatiles to detect herbivore- and pathogen-attacked neighbors and prime their defenses. Several individual volatile priming cues have been identified, but whether plants are able to integrate multiple cues from stress-related volatile blends remains poorly understood. Here, we investigated how maize plants respond to two herbivore-induced volatile priming cues with complementary information content, the green leaf volatile (Z)-3-hexenyl acetate (HAC) and the aromatic volatile indole. In the absence of herbivory, HAC directly induced defence gene expression, whereas indole had no effect. Upon induction by simulated herbivory, both volatiles increased jasmonate signalling, defence gene expression, and defensive secondary metabolite production and increased plant resistance. Plant resistance to caterpillars was more strongly induced in dual volatile-exposed plants than plants exposed to single volatiles.. Induced defence levels in dual volatile-exposed plants were significantly higher than predicted from the added effects of the individual volatiles, with the exception of induced plant volatile production, which showed no increase upon dual-exposure relative to single exposure. Thus, plants can integrate different volatile cues into strong and specific responses that promote herbivore defence induction and resistance. Integrating multiple volatiles may be beneficial, as volatile blends are more reliable indicators of future stress than single cues.
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Affiliation(s)
- Lingfei Hu
- Institute of Plant SciencesUniversity of BernBernSwitzerland
| | - Meng Ye
- Institute of Plant SciencesUniversity of BernBernSwitzerland
| | - Matthias Erb
- Institute of Plant SciencesUniversity of BernBernSwitzerland
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11
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Cofer TM, Seidl-Adams I, Tumlinson JH. From Acetoin to ( Z)-3-Hexen-1-ol: The Diversity of Volatile Organic Compounds that Induce Plant Responses. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:11197-11208. [PMID: 30293420 DOI: 10.1021/acs.jafc.8b03010] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Evidence that plants can respond to volatile organic compounds (VOCs) was first presented 35 years ago. Since then, over 40 VOCs have been found to induce plant responses. These include VOCs that are produced not only by plants but also by microbes and insects. Here, we summarize what is known about how these VOCs are produced and how plants detect and respond to them. In doing so, we highlight notable observations we believe are worth greater consideration. For example, the VOCs that induce plant responses appear to have little in common. They are derived from many different biosynthetic pathways and have few distinguishing chemical or structural features. Likewise, plants appear to use several mechanisms to detect VOCs rather than a single dedicated "olfactory" system. Considering these observations, we advocate for more discovery-oriented experiments and propose that future research take a fresh look at the ways plants detect and respond to VOCs.
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Affiliation(s)
- Tristan M Cofer
- Center for Chemical Ecology, Department of Entomology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Irmgard Seidl-Adams
- Center for Chemical Ecology, Department of Entomology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - James H Tumlinson
- Center for Chemical Ecology, Department of Entomology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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12
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Feng K, Wang LY, Liao DJ, Lu XP, Hu DJ, Liang X, Zhao J, Mo ZY, Li SP. Potential molecular mechanisms for fruiting body formation of Cordyceps illustrated in the case of Cordyceps sinensis. Mycology 2017; 8:231-258. [PMID: 30123644 PMCID: PMC6059060 DOI: 10.1080/21501203.2017.1365314] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/04/2017] [Indexed: 11/30/2022] Open
Abstract
The fruiting body formation mechanisms of Cordyceps sinensis are still unclear. To explore the mechanisms, proteins potentially related to the fruiting body formation, proteins from fruiting bodies, and mycelia of Cordyceps species were assessed by using two-dimensional fluorescence difference gel electrophoresis, and the differential expression proteins were identified by matrix-assisted laser desorption/ionisation tandem time of flight mass spectrometry. The results showed that 198 differential expression proteins (252 protein spots) were identified during the fruiting body formation of Cordyceps species, and 24 of them involved in fruiting body development in both C. sinensis and other microorganisms. Especially, enolase and malate dehydrogenase were first found to play an important role in fruiting body development in macro-fungus. The results implied that cAMP signal pathway involved in fruiting body development of C. sinensis, meanwhile glycometabolism, protein metabolism, energy metabolism, and cell reconstruction were more active during fruiting body development. It has become evident that fruiting body formation of C. sinensis is a highly complex differentiation process and requires precise integration of a number of fundamental biological processes. Although the fruiting body formation mechanisms for all these activities remain to be further elucidated, the possible mechanism provides insights into the culture of C. sinensis.
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Affiliation(s)
- Kun Feng
- State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
| | - Lan-Ying Wang
- State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China.,Department of Chemistry and Pharmacy, Zhuhai College of Jilin University, Zhuhai, China
| | - Dong-Jiang Liao
- The State Key Laboratory of Respiratory Diseases, Guangzhou Medical University, Guangzhou, China
| | - Xin-Peng Lu
- The State Key Laboratory of Respiratory Diseases, Guangzhou Medical University, Guangzhou, China
| | - De-Jun Hu
- State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
| | | | - Jing Zhao
- State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
| | - Zi-Yao Mo
- The State Key Laboratory of Respiratory Diseases, Guangzhou Medical University, Guangzhou, China
| | - Shao-Ping Li
- State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
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13
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Zheng J, Yu J, Jia M, Zheng L, Feng Y. Indole enhances the survival of Pantoea ananatis YJ76 in face of starvation conditions. J Basic Microbiol 2017; 57:633-639. [PMID: 28485502 DOI: 10.1002/jobm.201700027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/27/2017] [Accepted: 04/18/2017] [Indexed: 11/07/2022]
Abstract
Pantoea ananatis YJ76 is an indole-producing predominant diazotrophic endophyte isolated from rice having multiple growth-promoting effects on host plant. As a decomposition metabolite of L-tryptophan (L-Trp), indole is confirmed to regulate various physiological processes of bacteria. In this research, we found that indole significantly improves the survival of YJ76 in face of starvation conditions and the promoting effect is related to the glycogen accumulation promoted by indole, which is much more significant in the middle decline phase than in other growth phases. Since carbon storage regulator CsrA is a key inhibiting factor on the storage of glycogen in bacteria, we explored the relation between indole-enhanced glycogen accumulation and csrA expression and found that there is a positive correlation between indole-enhanced glycogen accumulation and the indole-inhibited csrA expression in YJ76, which implies the potential relation between CsrA regulation and indole regulatory pathway.
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Affiliation(s)
- Jing Zheng
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Jiajia Yu
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Mengqi Jia
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Liping Zheng
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Yongjun Feng
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China
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14
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Yang Q, Pande GSJ, Wang Z, Lin B, Rubin RA, Vora GJ, Defoirdt T. Indole signalling and (micro)algal auxins decrease the virulence of Vibrio campbellii, a major pathogen of aquatic organisms. Environ Microbiol 2017; 19:1987-2004. [PMID: 28251783 DOI: 10.1111/1462-2920.13714] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/25/2017] [Indexed: 12/23/2022]
Abstract
Vibrios belonging to the Harveyi clade are major pathogens of marine vertebrates and invertebrates, causing major losses in wild and cultured organisms. Despite their significant impact, the pathogenicity mechanisms of these bacteria are not yet completely understood. In this study, the impact of indole signalling on the virulence of Vibrio campbellii was investigated. Elevated indole levels significantly decreased motility, biofilm formation, exopolysaccharide production and virulence to crustacean hosts. Indole furthermore inhibited the three-channel quorum sensing system of V. campbellii, a regulatory mechanism that is required for full virulence of the pathogen. Further, indole signalling was found to interact with the stress sigma factor RpoS. Together with the observations that energy-consuming processes (motility and bioluminescence) are downregulated, and microarray-based transcriptomics demonstrating that indole decreases the expression of genes involved in energy and amino acid metabolism, the data suggest that indole is a starvation signal in V. campbellii. Finally, it was found that the auxins indole-3-acetic acid and indole-3-acetamide, which were produced by various (micro)algae sharing the aquatic environment with V. campbellii, have a similar effect as observed for indole. Auxins might, therefore, have a significant impact on the interactions between vibrios, (micro)algae and higher organisms, with major ecological and practical implications.
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Affiliation(s)
- Qian Yang
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Gent, Belgium
| | | | - Zheng Wang
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC, USA
| | - Baochuan Lin
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC, USA
| | - Robert A Rubin
- Mathematics Department, Whittier College, Whittier, CA, USA
| | - Gary J Vora
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC, USA
| | - Tom Defoirdt
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Gent, Belgium.,Center for Microbial Ecology and Technology (cmet), Ghent University, Gent, Belgium
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15
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Kim J, Shin B, Park C, Park W. Indole-Induced Activities of β-Lactamase and Efflux Pump Confer Ampicillin Resistance in Pseudomonas putida KT2440. Front Microbiol 2017; 8:433. [PMID: 28352264 PMCID: PMC5348495 DOI: 10.3389/fmicb.2017.00433] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/01/2017] [Indexed: 11/13/2022] Open
Abstract
Indole, which is widespread in microbial communities, has received attention because of its effects on bacterial physiology. Pseudomonas putida and Pseudomonas aeruginosa can acquire ampicillin (Amp) resistance during growth on indole-Amp agar. Transcriptome, mutant, and inhibitor studies have suggested that Amp resistance induced by indole can be attributed to increased gene expression of ttgAB encoding two genes of RND-type multidrug efflux operons and an ampC encoding β-lactamase. Expression, enzyme activities, and mutational analyses indicated that AmpC β-lactamase is important for acquiring Amp resistance of P. putida in the presence of indole. Here, we show, for the first time, that volatile indole increased Amp-resistant cells. Consistent with results of the volatile indole assay, a low concentration of indole in liquid culture promoted growth initially, but led to mutagenesis after indole was depleted, which could not be observed at high indole concentrations. Interestingly, ttgAB and ampC gene expression levels correlate with the concentration of indole, which might explain the low number of Amp-mutated cells in high indole concentrations. The expression levels of genes involved in mutagenesis, namely rpoS, recA, and mutS, were also modulated by indole. Our data indicates that indole reduces Amp-induced heterogeneity by promoting expression of TtgABC or MexAB-OprM efflux pumps and the indole-induced β-lactamase in P. putida and P. aeruginosa.
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Affiliation(s)
- Jisun Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul Korea
| | - Bora Shin
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul Korea
| | - Chulwoo Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul Korea
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16
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Lin L, Zhang J. Role of intestinal microbiota and metabolites on gut homeostasis and human diseases. BMC Immunol 2017; 18:2. [PMID: 28061847 PMCID: PMC5219689 DOI: 10.1186/s12865-016-0187-3] [Citation(s) in RCA: 391] [Impact Index Per Article: 55.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/20/2016] [Indexed: 12/12/2022] Open
Abstract
Background A vast diversity of microbes colonizes in the human gastrointestinal tract, referred to intestinal microbiota. Microbiota and products thereof are indispensable for shaping the development and function of host innate immune system, thereby exerting multifaceted impacts in gut health. Methods This paper reviews the effects on immunity of gut microbe-derived nucleic acids, and gut microbial metabolites, as well as the involvement of commensals in the gut homeostasis. We focus on the recent findings with an intention to illuminate the mechanisms by which the microbiota and products thereof are interacting with host immunity, as well as to scrutinize imbalanced gut microbiota (dysbiosis) which lead to autoimmune disorders including inflammatory bowel disease (IBD), Type 1 diabetes (T1D) and systemic immune syndromes such as rheumatoid arthritis (RA). Results In addition to their well-recognized benefits in the gut such as occupation of ecological niches and competition with pathogens, commensal bacteria have been shown to strengthen the gut barrier and to exert immunomodulatory actions within the gut and beyond. It has been realized that impaired intestinal microbiota not only contribute to gut diseases but also are inextricably linked to metabolic disorders and even brain dysfunction. Conclusions A better understanding of the mutual interactions of the microbiota and host immune system, would shed light on our endeavors of disease prevention and broaden the path to our discovery of immune intervention targets for disease treatment.
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Affiliation(s)
- Lan Lin
- Department of Bioengineering, Medical School, Southeast University, Nanjing, 210009, People's Republic of China.
| | - Jianqiong Zhang
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, Nanjing, 210009, People's Republic of China.
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17
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Zepeda Mendoza ML, Lundberg J, Ivarsson M, Campos P, Nylander JAA, Sallstedt T, Dalen L. Metagenomic Analysis from the Interior of a Speleothem in Tjuv-Ante's Cave, Northern Sweden. PLoS One 2016; 11:e0151577. [PMID: 26985997 PMCID: PMC4795671 DOI: 10.1371/journal.pone.0151577] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 03/01/2016] [Indexed: 02/01/2023] Open
Abstract
Speleothems are secondary mineral deposits normally formed by water supersaturated with calcium carbonate percolating into underground caves, and are often associated with low-nutrient and mostly non-phototrophic conditions. Tjuv-Ante's cave is a shallow-depth cave formed by the action of waves, with granite and dolerite as major components, and opal-A and calcite as part of the speleothems, making it a rare kind of cave. We generated two DNA shotgun sequencing metagenomic datasets from the interior of a speleothem from Tjuv-Ante's cave representing areas of old and relatively recent speleothem formation. We used these datasets to perform i) an evaluation of the use of these speleothems as past biodiversity archives, ii) functional and taxonomic profiling of the speleothem's different formation periods, and iii) taxonomic comparison of the metagenomic results to previous microscopic analyses from a nearby speleothem of the same cave. Our analyses confirm the abundance of Actinobacteria and fungi as previously reported by microscopic analyses on this cave, however we also discovered a larger biodiversity. Interestingly, we identified photosynthetic genes, as well as genes related to iron and sulphur metabolism, suggesting the presence of chemoautotrophs. Furthermore, we identified taxa and functions related to biomineralization. However, we could not confidently establish the use of this type of speleothems as biological paleoarchives due to the potential leaching from the outside of the cave and the DNA damage that we propose has been caused by the fungal chemical etching.
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Affiliation(s)
| | - Johannes Lundberg
- Department of Botany, Swedish Museum of Natural History, Stockholm, Sweden
| | - Magnus Ivarsson
- Department of Palaeobiology and the Nordic Center for Earth Evolution (NordCEE), Swedish Museum of Natural History, Stockholm, Sweden
| | - Paula Campos
- Centre for GeoGenetics, University of Copenhagen, Natural History Museum of Denmark, Copenhagen, Denmark
| | - Johan A. A. Nylander
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Therese Sallstedt
- Department of Palaeobiology and the Nordic Center for Earth Evolution (NordCEE), Swedish Museum of Natural History, Stockholm, Sweden
| | - Love Dalen
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
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18
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Lee JH, Wood TK, Lee J. Roles of Indole as an Interspecies and Interkingdom Signaling Molecule. Trends Microbiol 2015; 23:707-718. [DOI: 10.1016/j.tim.2015.08.001] [Citation(s) in RCA: 238] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/22/2015] [Accepted: 08/05/2015] [Indexed: 02/08/2023]
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19
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Indole: a signaling molecule or a mere metabolic byproduct that alters bacterial physiology at a high concentration? J Microbiol 2015; 53:421-8. [PMID: 26115989 DOI: 10.1007/s12275-015-5273-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/17/2015] [Accepted: 06/18/2015] [Indexed: 10/23/2022]
Abstract
Indole is an organic compound that is widespread in microbial communities inhabiting diverse habitats, like the soil environment and human intestines. Measurement of indole production is a traditional method for the identification of microbial species. Escherichia coli can produce millimolar concentrations of indole in the stationary growth phase under nutrient-rich conditions. Indole has received considerable attention because of its remarkable effects on various biological functions of the microbial communities, for example, biofilm formation, motility, virulence, plasmid stability, and antibiotic resistance. Indole may function as an intercellular signaling molecule, like a quorum-sensing signal. Nevertheless, a receptor system for indole and the function of this compound in coordinated behavior of a microbial population (which are requirements for a true signaling molecule) have not yet been confirmed. Recent findings suggest that a long-known quorum-sensing regulator, E. coli's SdiA, cannot recognize indole and that this compound may simply cause membrane disruption and energy reduction, which can lead to various changes in bacterial physiology including unstable folding of a quorum-sensing regulator. Indole appears to be responsible for acquisition of antibiotic resistance via the formation of persister cells and activation of an exporter. This review highlights and summarizes the current knowledge about indole as a multitrophic molecule among bacteria, together with recently identified new avenues of research.
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20
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Erb M, Veyrat N, Robert CAM, Xu H, Frey M, Ton J, Turlings TCJ. Indole is an essential herbivore-induced volatile priming signal in maize. Nat Commun 2015; 6:6273. [PMID: 25683900 PMCID: PMC4339915 DOI: 10.1038/ncomms7273] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 01/12/2015] [Indexed: 12/26/2022] Open
Abstract
Herbivore-induced volatile organic compounds prime non-attacked plant tissues to respond more strongly to subsequent attacks. However, the key volatiles that trigger this primed state remain largely unidentified. In maize, the release of the aromatic compound indole is herbivore-specific and occurs earlier than other induced responses. We therefore hypothesized that indole may be involved in airborne priming. Using indole-deficient mutants and synthetic indole dispensers, we show that herbivore-induced indole enhances the induction of defensive volatiles in neighbouring maize plants in a species-specific manner. Furthermore, the release of indole is essential for priming of mono- and homoterpenes in systemic leaves of attacked plants. Indole exposure markedly increases the herbivore-induced production of the stress hormones jasmonate-isoleucine conjugate and abscisic acid, which represents a likely mechanism for indole-dependent priming. These results demonstrate that indole functions as a rapid and potent aerial priming agent that prepares systemic tissues and neighbouring plants for incoming attacks.
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Affiliation(s)
- Matthias Erb
- Institute of Plant Sciences, Department of Biology, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
| | - Nathalie Veyrat
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Faculty of Science, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland
| | - Christelle A. M. Robert
- Institute of Plant Sciences, Department of Biology, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
| | - Hao Xu
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Faculty of Science, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland
| | - Monika Frey
- Lehrstuhl für Genetik, TU Munich, Emil-Ramann-Straβe 8, 85354 Freising, Germany
| | - Jurriaan Ton
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, S10 2TN Sheffield, UK
| | - Ted C. J. Turlings
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Faculty of Science, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland
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21
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Lee JH, Kim YG, Baek KH, Cho MH, Lee J. The multifaceted roles of the interspecies signalling molecule indole inAgrobacterium tumefaciens. Environ Microbiol 2014; 17:1234-44. [DOI: 10.1111/1462-2920.12560] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 07/02/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Jin-Hyung Lee
- School of Chemical Engineering; Yeungnam University; Gyeongsan 712-749 Korea
| | - Yong-Guy Kim
- School of Chemical Engineering; Yeungnam University; Gyeongsan 712-749 Korea
| | - Kwang-Hyun Baek
- School of Biotechnology; Yeungnam University; Gyeongsan 712-749 Korea
| | - Moo Hwan Cho
- School of Chemical Engineering; Yeungnam University; Gyeongsan 712-749 Korea
| | - Jintae Lee
- School of Chemical Engineering; Yeungnam University; Gyeongsan 712-749 Korea
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22
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Tan Z, Li H, Pan H, Zhou X, Liu X, Luo N, Hu W, Li Y. Characterization of four type IV pilin homologues in Stigmatella aurantiaca DSM17044 by heterologous expression in Myxococcus xanthus. PLoS One 2013; 8:e75105. [PMID: 24058653 PMCID: PMC3776727 DOI: 10.1371/journal.pone.0075105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 08/09/2013] [Indexed: 11/19/2022] Open
Abstract
As prokaryotic models for multicellular development, Stigmatella aurantiaca and Myxococcus xanthus share many similarities in terms of social behaviors, such as gliding motility. Our current understanding of myxobacterial grouped-cell motilities comes mainly from the research on M. xanthus, which shows that filamentous type IV pili (TFP), composed of type IV pilin (also called PilA protein) subunits, are the key apparatus for social motility (S-motility). However, little is known about the pilin protein in S. aurantiaca. We cloned and sequenced four genes (pilA(Sa1~4)) from S. aurantiaca DSM17044 that are homologous to pilA(Mx) (pilA gene in M. xanthus DK1622). The homology and similarities among pilA(Sa) proteins and other myxobacterial homologues were systematically analyzed. To determine their potential biological functions, the four pilA(Sa) genes were expressed in M. xanthus DK10410 (ΔpilA(Mx)), which did not restore S-motility on soft agar or EPS production to host cells. After further analysis of the motile behaviors in a methylcellulose solution, the M. xanthus strains were categorized into three types. YL6101, carrying pilA(Sa1), and YL6104, carrying pilA(Sa4), produced stable but unretractable surface pili; YL6102, carrying pilA(Sa2), produced stable surface pili and exhibited reduced TFP-dependent motility in methylcellulose; YL6103, carrying pilA(Sa3), produced unstable surface pili. Based on these findings, we propose that pilA(Sa2) might be responsible for the type IV pilin production involved in group motility in S. aurantiaca DSM17044. After examining the developmental processes, it was suggested that the expression of PilA(Sa4) protein might have positive effects on the fruiting body formation of M. xanthus DK10410 cells. Moreover, the formation of fruiting body in M. xanthus cells with stable exogenous TFPSa were compensated by mixing them with S. aurantiaca DSM17044 cells. Our results shed some light on the features and functions of type IV pilin homologues in S. aurantiaca.
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Affiliation(s)
- Zaigao Tan
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Haoming Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Hongwei Pan
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Xiuwen Zhou
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Xin Liu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Ningning Luo
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Wei Hu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
- * E-mail:
| | - Yuezhong Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
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23
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Kim J, Hong H, Heo A, Park W. Indole toxicity involves the inhibition of adenosine triphosphate production and protein folding in Pseudomonas putida. FEMS Microbiol Lett 2013; 343:89-99. [PMID: 23527579 DOI: 10.1111/1574-6968.12135] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/08/2013] [Accepted: 03/15/2013] [Indexed: 01/11/2023] Open
Abstract
High concentrations of indole are known to be toxic to cells due to perturbations in membrane potential. Here, we report for the first time a transcriptome analysis of a soil model bacterium, Pseudomonas putida KT2440, under indole treatment. We demonstrated that 47 genes are differentially expressed, including 11 genes involved in the tricarboxylic acid cycle (TCA cycle) and 12 genes involved in chaperone and protease functions (hslV, hslU, htpG, grpE, dnaK, ibpA, groEL, groES, clpB, lon-1, lon-2, and hflk). Mutant analysis supported the observation that protease genes including hslU are essential for the indole resistance of Pseudomonas strains. Subsequent biochemical analyses have shown that indole increases the NADH/NAD(+) ratio and decreases the adenosine triphosphate (ATP) concentration inside cells, due to membrane perturbation and higher expression of TCA cycle genes in the presence of indole. This energy reduction leads to a reduction in cell size and an enhancement of biofilm formation in P. putida. The observed upregulation in many chaperones and proteases led us to speculate that protein folding might be inhibited by indole treatment. Interestingly, our in vitro protein-refolding assay using malate dehydrogenase with purified GroEL/GroES demonstrated that indole interferes with protein folding. Taken together, our data provide new evidence that indole causes toxicity to P. putida by inhibiting cellular energy production and protein folding.
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Affiliation(s)
- Jisun Kim
- Department of Environmental Science and Ecological Engineering, Korea University, Seoul, Korea
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Kim YG, Lee JH, Cho MH, Lee J. Indole and 3-indolylacetonitrile inhibit spore maturation in Paenibacillus alvei. BMC Microbiol 2011; 11:119. [PMID: 21619597 PMCID: PMC3126691 DOI: 10.1186/1471-2180-11-119] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/27/2011] [Indexed: 12/26/2022] Open
Abstract
Background Bacteria use diverse signaling molecules to ensure the survival of the species in environmental niches. A variety of both Gram-positive and Gram-negative bacteria produce large quantities of indole that functions as an intercellular signal controlling diverse aspects of bacterial physiology. Results In this study, we sought a novel role of indole in a Gram-positive bacteria Paenibacillus alvei that can produce extracellular indole at a concentration of up to 300 μM in the stationary phase in Luria-Bertani medium. Unlike previous studies, our data show that the production of indole in P. alvei is strictly controlled by catabolite repression since the addition of glucose and glycerol completely turns off the indole production. The addition of exogenous indole markedly inhibits the heat resistance of P. alvei without affecting cell growth. Observation of cell morphology with electron microscopy shows that indole inhibits the development of spore coats and cortex in P. alvei. As a result of the immature spore formation of P. alvei, indole also decreases P. alvei survival when exposed to antibiotics, low pH, and ethanol. Additionally, indole derivatives also influence the heat resistance; for example, a plant auxin, 3-indolylacetonitrile dramatically (2900-fold) decreased the heat resistance of P. alvei, while another auxin 3-indoleacetic acid had a less significant influence on the heat resistance of P. alvei. Conclusions Together, our results demonstrate that indole and plant auxin 3-indolylacetonitrile inhibit spore maturation of P. alvei and that 3-indolylacetonitrile presents an opportunity for the control of heat and antimicrobial resistant spores of Gram-positive bacteria.
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Affiliation(s)
- Yong-Guy Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeonsangbuk-do 712-749, Korea
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25
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Abstract
Bacteria can utilize signal molecules to coordinate their behavior to survive in dynamic multispecies communities. Indole is widespread in the natural environment, as a variety of both Gram-positive and Gram-negative bacteria (to date, 85 species) produce large quantities of indole. Although it has been known for over 100 years that many bacteria produce indole, the real biological roles of this molecule are only now beginning to be unveiled. As an intercellular signal molecule, indole controls diverse aspects of bacterial physiology, such as spore formation, plasmid stability, drug resistance, biofilm formation, and virulence in indole-producing bacteria. In contrast, many non-indole-producing bacteria, plants and animals produce diverse oxygenases which may interfere with indole signaling. It appears indole plays an important role in bacterial physiology, ecological balance, and possibly human health. Here we discuss our current knowledge and perspectives on indole signaling.
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Affiliation(s)
- Jin-Hyung Lee
- School of Display & Chemical Engineering, Yeungnam University, Gyeongsan, Korea
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26
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Lelong C, Aguiluz K, Luche S, Kuhn L, Garin J, Rabilloud T, Geiselmann J. The Crl-RpoS Regulon of Escherichia coli. Mol Cell Proteomics 2007; 6:648-59. [PMID: 17224607 DOI: 10.1074/mcp.m600191-mcp200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The RpoS subunit of RNA polymerase controls the expression of numerous genes involved in stationary phase and in response to different stress conditions. The regulatory protein Crl increases the activity of RpoS by direct interaction with the RpoS holoenzyme. To define the extent of the Crl regulon, we used two-dimensional SDS-PAGE to measure the role of Crl in regulating the expression of the Escherichia coliproteome in stationary phase at 30 degrees C. By comparing the proteome of four strains (wild type, crl(-), rpoS(-), and crl(-)rpoS(-)), we observed that the intensity of 74 spots was modified in at least one mutant context. 62 spots were identified by mass spectrometry and correspond to 40 distinct proteins. They were classified in four main categories: DNA metabolism, central metabolism, response to environmental modifications, and miscellaneous. Three proteins were specifically involved in quorum sensing: TnaA (the tryptophanase that converts tryptophan to indole), WrbA (Trp repressor-binding protein), and YgaG (homologous to LuxS, autoinducer-2 synthase). Because little is known about the regulation of Crl expression, we investigated the influence of diffusible molecules on the expression of Crl. Using Western blotting experiments, we showed that, at 30 degrees C, a diffusible molecule(s) produced during the transition phase between the exponential and stationary phases induces a premature expression of Crl. Indole was tested as one of the potential candidates: at 37 degrees C, it is present in the extracellular medium at a constant concentration, but at 30 degrees C, its concentration peaks during the transition phase. When indole was added to the culture medium, it also induced prematurely the expression of Crl at both the transcriptional and translational levels in a Crl-dependent manner. Crl may thus be considered a new environmental sensor via the indole concentration.
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Affiliation(s)
- Cécile Lelong
- Laboratoire Adaptation et Pathogénie des Microorganismes, Institut Jean Roget, Campus de la Merci, Université Joseph Fourier, BP170, 38042 Grenoble Cedex 9, France.
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