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Chemotactic responses of Brugia pahangi infective third-stage larvae to tris(hydroxymethyl)aminomethane-related compounds and amino acids. J Helminthol 2021; 95:e72. [PMID: 34879884 DOI: 10.1017/s0022149x21000705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since the exogenous compound tris(hydroxymethyl)aminomethane (Tris) showed a potent chemoattractant activity for Brugia pahangi infective third-stage larvae (L3), it was assumed that, in natural infection to a host, filarial L3 can be expected to recognize an endogenous Tris-related compound. In addition, a few amino acids have been identified as water-soluble attractants for second-stage juveniles of Meloidogyne incognita, a plant parasitic nematode. Therefore, the present study assesses the in vitro chemotactic responses of B. pahangi L3 to Tris-related compounds and amino acids using an agar-plate assay. Among Tris-related compounds, 2-amino-1,3-propanediol (APD) and 2-amino-2-methyl-1,3-propanediol (AMPD) exhibited a potent chemoattractant activity for filarial L3 at a level similar to Tris. Furthermore, arginine (Arg) was identified as a potent attractant for filarial L3 among amino acids. In addition, filarial L3 were attracted to Arg, APD and AMPD in mild alkaline conditions rather than acidic conditions. The chemoattractant activity of the three compounds for filarial L3 was observed in concentrations between 6.3 and 200 mm. This is the first report to demonstrate that Arg, APD and AMPD are potent chemoattractants for B. pahangi L3. Endogenous Arg and APD, in particular, may be involved in the regulation of the chemotactic behaviour of filarial L3 in the infection to a host. The present results will help to elucidate the mechanism of filarial skin-penetrating invasion of a host.
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Moroz LL, Nikitin MA, Poličar PG, Kohn AB, Romanova DY. Evolution of glutamatergic signaling and synapses. Neuropharmacology 2021; 199:108740. [PMID: 34343611 DOI: 10.1016/j.neuropharm.2021.108740] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/13/2022]
Abstract
Glutamate (Glu) is the primary excitatory transmitter in the mammalian brain. But, we know little about the evolutionary history of this adaptation, including the selection of l-glutamate as a signaling molecule in the first place. Here, we used comparative metabolomics and genomic data to reconstruct the genealogy of glutamatergic signaling. The origin of Glu-mediated communications might be traced to primordial nitrogen and carbon metabolic pathways. The versatile chemistry of L-Glu placed this molecule at the crossroad of cellular biochemistry as one of the most abundant metabolites. From there, innovations multiplied. Many stress factors or injuries could increase extracellular glutamate concentration, which led to the development of modular molecular systems for its rapid sensing in bacteria and archaea. More than 20 evolutionarily distinct families of ionotropic glutamate receptors (iGluRs) have been identified in eukaryotes. The domain compositions of iGluRs correlate with the origins of multicellularity in eukaryotes. Although L-Glu was recruited as a neuro-muscular transmitter in the early-branching metazoans, it was predominantly a non-neuronal messenger, with a possibility that glutamatergic synapses evolved more than once. Furthermore, the molecular secretory complexity of glutamatergic synapses in invertebrates (e.g., Aplysia) can exceed their vertebrate counterparts. Comparative genomics also revealed 15+ subfamilies of iGluRs across Metazoa. However, most of this ancestral diversity had been lost in the vertebrate lineage, preserving AMPA, Kainate, Delta, and NMDA receptors. The widespread expansion of glutamate synapses in the cortical areas might be associated with the enhanced metabolic demands of the complex brain and compartmentalization of Glu signaling within modular neuronal ensembles.
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Affiliation(s)
- Leonid L Moroz
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
| | - Mikhail A Nikitin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119991, Russia; Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia
| | - Pavlin G Poličar
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Faculty of Computer and Information Science, University of Ljubljana, SI-1000, Ljubljana, Slovenia
| | - Andrea B Kohn
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA
| | - Daria Y Romanova
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
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Xu Z, Wang D, Tang W, Wang L, Li Q, Lu Z, Liu H, Zhong Y, He T, Guo S. Phytoremediation of cadmium-polluted soil assisted by D-gluconate-enhanced Enterobacter cloacae colonization in the Solanum nigrum L. rhizosphere. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:139265. [PMID: 32416401 DOI: 10.1016/j.scitotenv.2020.139265] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/23/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
Microbe-assisted phytoremediation for Cd-polluted soil is being regarded increasingly. However, the availability of microbes that can collaborate with Cd-hyperaccumulators effectively has become one of bottlenecks restricting the remediation efficiency. A siderophore-producing bacterium (Y16; Enterobacter cloacae) isolated from the rhizospheric soil of Cd-hyperaccumulator Solanum nigrum L. was identified by 16S rRNA gene sequencing and biochemical analysis, and then used for analyzing microbial chemotaxis, carbon source utilization, and insoluble P/Cd mobilization capacities. Besides, a soil-pot trial was performed to underlie the phytoremediation mechanism of Cd-polluted soil assisted by D-gluconate-enhanced Enterobacter cloacae colonization (DEYC) in the Solanum nigrum L. rhizosphere. Results displayed that D-gluconate was an effective chemoattractant and carbon source strengthening Y16 colonization, and Y16 exhibited strong abilities to mobilize insoluble P/Cd in shake flask by extracellular acidification (p < 0.05). In the soil-pot trial, DEYC observably enhanced soil Cd phytoextraction by Solanum nigrum L., and increased microbial diversity according to alpha- and beta-diversity analysis (p < 0.05). Taxonomic distribution and co-occurrence network analysis suggested that DEYC increased relative abundances of dominant microbial taxa associated with soil acidification (Acidobacteria-6), indoleacetic acid secretion (Ensifer adhaerens), soil fertility improvement (Flavisolibacter, Bdellovibrio bacteriovorus, and Candidatus nitrososphaera), and insoluble Cd mobilization (Massilia timonae) at different classification levels. Importantly, COGs analysis further shown that DEYC aroused the up-regulation of key genes related to chemotactic motility, carbon fixation, TCA cycle, and propanoate metabolism. These results indicated that DEYC drove the rhizospheric enrichment of pivotal microbial taxa directly or indirectly involved in soil Cd mobilization, meanwhile distinctly promoted plant growth for accumulating more mobilizable Cd. Therefore, Y16 could be used as bio-inoculants for assisting phytoremediation of Cd-polluted soil.
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Affiliation(s)
- Zhimin Xu
- School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China; Guangdong Provincial Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control, Guangzhou 510225, China
| | - Dongsheng Wang
- Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China
| | - Wanpeng Tang
- Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China
| | - Lili Wang
- Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China.
| | - Qusheng Li
- Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China
| | - Ziyan Lu
- School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Guangdong Provincial Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control, Guangzhou 510225, China
| | - Hui Liu
- School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Guangdong Provincial Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control, Guangzhou 510225, China
| | - Yuming Zhong
- School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Guangdong Provincial Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control, Guangzhou 510225, China
| | - Tao He
- Key Laboratory of Environmental Pollution and Health of Guangdong Province, School of Environment, Jinan University, Guangzhou 510632, China
| | - Shihong Guo
- Fujian Provincial Academy of Environmental Science, Fuzhou 350013, China
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Ma L, Zheng SC, Zhang TK, Liu ZY, Wang XJ, Zhou XK, Yang CG, Duo JL, Mo MH. Effect of nicotine from tobacco root exudates on chemotaxis, growth, biocontrol efficiency, and colonization by Pseudomonas aeruginosa NXHG29. Antonie Van Leeuwenhoek 2018; 111:1237-1257. [PMID: 29397489 DOI: 10.1007/s10482-018-1035-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/28/2018] [Indexed: 10/18/2022]
Abstract
Accumulated evidence suggests that root exudates have a major role in mediating plant-microbe interactions in the rhizosphere. Here, we characterized tobacco root exudates (TREs) by GC-MS and nicotine, scopoletin, and octadecane were identified as three main components of TREs. Qualitative and quantitative chemotaxis assays revealed that Pseudomonas aeruginosa NXHG29 with antagonistic activity displayed positive chemotactic responses towards TREs and their three main components (nicotine, scopoletin, octadecane) and its enhanced chemotaxis were induced by these substances in a concentration-dependent manner. Furthermore, following GC-MS and chemotaxis analysis, nicotine was selected as the target for evaluation of the effect on NXHG29 regarding antagonism, growth, root colonization and biocontrol efficiency. Results of in vitro studies showed that nicotine as a sole carbon source could enhance growth of NXHG29 and significantly increased the antagonism of NXHG29. We also demonstrated that nicotine exerted enhancing effects on the colonization ability of NXHG29 on tobacco roots by combining CLSM observations with investigation of population level dynamics by selective dilution plating method. Results from greenhouse experiments suggested nicotine exhibited stimulatory effects on the biocontrol efficiency of NXHG29 against bacterial wilt and black shank on tobacco. The stimulatory effect of nicotine was affected by the concentration and timing of nicotine application and further supported by the results of population level of NXHG29 on tobacco roots. This is the first report on the enhancement effect of nicotine from TREs on an antagonistic bacterium for its root colonization, control of soil-borne pathogens, regarding the chemotaxis and in vitro antagonism and growth.
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Affiliation(s)
- Li Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China.
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming, 650091, People's Republic of China.
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China.
| | - Shuai Chao Zheng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Ti Kun Zhang
- Pu'er Branch of Yunnan Tobacco Company, Pu'er, 665000, People's Republic of China
- Yunnan Corporation of China National Tobacco Corporation, Kunming, 650202, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Zi Yi Liu
- Pu'er Branch of Yunnan Tobacco Company, Pu'er, 665000, People's Republic of China
- Yunnan Corporation of China National Tobacco Corporation, Kunming, 650202, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Xue Jian Wang
- Pu'er Branch of Yunnan Tobacco Company, Pu'er, 665000, People's Republic of China
- Yunnan Corporation of China National Tobacco Corporation, Kunming, 650202, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Xing Kui Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Plant Disease & Pest, Yunnan University, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Cheng Gang Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Plant Disease & Pest, Yunnan University, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Jin Ling Duo
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
| | - Ming He Mo
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, No.2 Cuihubei road, Kunming, 650091, People's Republic of China
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming, 650091, People's Republic of China
- Biocontrol Engineering Research Center of Crop Disease & Pest, Yunnan University, Kunming, 650091, Yunnan Province, People's Republic of China
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Hayashi N, Yokotani A, Yamamoto M, Kososhi M, Morita M, Fukunishi C, Nishizawa N, Gotoh N. Extracellular Signals of a Human Epithelial Colorectal Adenocarcinoma (Caco-2) Cell Line Facilitate the Penetration of Pseudomonas aeruginosa PAO1 Strain through the Mucin Layer. Front Cell Infect Microbiol 2017; 7:415. [PMID: 28983473 PMCID: PMC5613098 DOI: 10.3389/fcimb.2017.00415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/06/2017] [Indexed: 01/25/2023] Open
Abstract
Pseudomonas aeruginosa can penetrate the layer of mucus formed by host intestinal epithelial cells, often resulting in sepsis in immunocompromised patients. We have previously demonstrated that P. aeruginosa can penetrate the mucin layer by flagellar motility and the degradation of the mucin layer. However, it remains unclear how P. aeruginosa initially recognizes epithelial cells. Using the human epithelial colorectal adenocarcinoma (Caco-2) cell line, we investigated extracellular signaling that could facilitate the penetration of P. aeruginosa through the mucin layer. The supernatant from Caco-2 cell cultures increased penetration of P. aeruginosa through an artificial mucin layer. The Caco-2 cell supernatant increased bacterial flagella-dependent swarming motility, but it did not influence P. aeruginosa growth or protease activity. Filtering of the Caco-2 cell supernatant indicated that proteins weighing <10 kDa increased mucin penetration, swarming motility, and, based on a tethered cell assay, induced acceleration of the flagellar filament rotational rate. Furthermore, a capillary assay showed that <10 kDa proteins in the Caco-2 cell supernatant attracted P. aeruginosa cells. Finally, we identified that growth-regulated oncogene-α (GRO-α) secreted by Caco-2 cells was a factor facilitating flagellar filament rotation and swarming motility, although it did not attract the bacteria. We conclude that penetration of the mucin layer by P. aeruginosa is facilitated by small proteins (<10 kDa) secreted by Caco-2 cells, both by inducing acceleration of flagellar motility and increasing chemotaxis.
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Affiliation(s)
- Naoki Hayashi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Atsushi Yokotani
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Masami Yamamoto
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Mariko Kososhi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Mayu Morita
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Chiaki Fukunishi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Nagisa Nishizawa
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
| | - Naomasa Gotoh
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical UniversityKyoto, Japan
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6
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Different nitrogen sources change the transcriptome of welan gum-producing strain Sphingomonas sp. ATCC 31555. Arch Microbiol 2017; 199:1055-1064. [DOI: 10.1007/s00203-017-1372-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/20/2017] [Accepted: 03/24/2017] [Indexed: 10/19/2022]
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Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that has long been known to chemotax. More recently, it has been established that chemotaxis is an important factor in the ability of P. aeruginosa to make biofilms. Genes that allow P. aeruginosa to chemotax are homologous with genes in the paradigmatic model organism for chemotaxis, Escherichia coli. However, P. aeruginosa is singly flagellated and E. coli has multiple flagella. Therefore, the regulation of counterclockwise/clockwise flagellar motor bias that allows E. coli to efficiently chemotax by runs and tumbles would lead to inefficient chemotaxis by P. aeruginosa, as half of a randomly oriented population would respond to a chemoattractant gradient in the wrong sense. How P. aeruginosa regulates flagellar rotation to achieve chemotaxis is not known. Here, we analyze the swimming trajectories of single cells in microfluidic channels and the rotations of cells tethered by their flagella to the surface of a variable-environment flow cell. We show that P. aeruginosa chemotaxes by symmetrically increasing the durations of both counterclockwise and clockwise flagellar rotations when swimming up the chemoattractant gradient and symmetrically decreasing rotation durations when swimming down the chemoattractant gradient. Unlike the case for E. coli, the counterclockwise/clockwise bias stays constant for P. aeruginosa. We describe P. aeruginosa’s chemotaxis using an analytical model for symmetric motor regulation. We use this model to do simulations that show that, given P. aeruginosa’s physiological constraints on motility, its distinct, symmetric regulation of motor switching optimizes chemotaxis. Chemotaxis has long been known to strongly affect biofilm formation by the opportunistic human pathogen P. aeruginosa, whose essential chemotaxis genes have homologues in E. coli, which achieves chemotaxis by biasing the relative probability of counterclockwise and clockwise flagellar rotation. However, the physiological difference between multiflagellated E. coli and singly flagellated P. aeruginosa implies that biased motor regulation should prevent P. aeruginosa populations from chemotaxing efficiently. Here, we used experiments, analytical modeling, and simulations to demonstrate that P. aeruginosa uses unbiased, symmetric regulation of the flagellar motor to maximize its chemotaxis efficiency. This mode of chemotaxis was not previously known and demonstrates a new variant of a paradigmatic signaling system in an important human pathogen.
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Sampedro I, Kato J, Hill JE. Elastin degradation product isodesmosine is a chemoattractant for Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2015; 161:1496-503. [PMID: 25855762 PMCID: PMC10727130 DOI: 10.1099/mic.0.000090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 04/01/2015] [Accepted: 04/03/2015] [Indexed: 12/24/2022]
Abstract
Previous studies have demonstrated that Pseudomonas aeruginosa PAO1 is chemotactic towards proteinogenic amino acids, however, the chemotaxis response of this strain towards non-proteinogenic amino acids and the specific chemoreceptors involved in this response are essentially unknown. In this study, we analysed the chemotactic response of PAO1 towards two degradation products of elastin, the lysine-rich, non-proteinogenic amino acids, desmosine and isodesmosine. We observed that isodesmosine, a potential biomarker for different diseases, served as a chemoattractant for PAO1. A screen of 251methyl-accepting chemotaxis proteins mutants of PAO1 identified PctA as the chemoreceptor for isodesmosine. We also showed that the positive chemotactic response to isodesmosine is potentially common by demonstrating chemoattraction in 12 of 15 diverse (in terms of source of isolation) clinical isolates, suggesting that the chemotactic response to this non-proteinogenic amino acid might be a conserved feature of acute infection isolates and thus could influence the colonization of potential infection sites.
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Affiliation(s)
- Inmaculada Sampedro
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA
| | - Junichi Kato
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Jane E. Hill
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA
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Seralathan MV, Sivanesan S, Nargunanathan S, Bafana A, Kannan K, Chakrabarti T. Chemotaxis-based endosulfan biotransformation: enrichment and isolation of endosulfan-degrading bacteria. ENVIRONMENTAL TECHNOLOGY 2015; 36:60-67. [PMID: 25409584 DOI: 10.1080/09593330.2014.937464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The study was conducted to isolate endosulfan biotransforming or biodegrading microbes based on chemotaxis. Pseudomonas aeruginosa strain KKc3, Ochrobactrum sp. strain KKc4, Achromobacter xylosoxidans strain KKc6 and Bacillus megaterium KKc7 were isolated based on their migration towards endosulfan in a soil column. Out of the four bacteria, B. megaterium converted endosulfan into toxic metabolite endosulfan sulphate, while the other three bacteria followed the non-toxic endosulfan diol pathway. The mixed culture system consisting of P. aeruginosa, Ochrobactrum sp and A. xylosoxidans could remove 94% of total endosulfan by using endosulfan as the sole source of sulphur.
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Affiliation(s)
- Muhil Vannan Seralathan
- a Environmental Health Division , National Environmental Engineering Research Institute , Nagpur 440022 , India
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Abstract
Pseudomonads sense changes in the concentration of chemicals in their environment and exhibit a behavioral response mediated by flagella or pili coupled with a chemosensory system. The two known chemotaxis pathways, a flagella-mediated pathway and a putative pili-mediated system, are described in this review. Pseudomonas shows chemotaxis response toward a wide range of chemicals, and this review includes a summary of them organized by chemical structure. The assays used to measure positive and negative chemotaxis swimming and twitching Pseudomonas as well as improvements to those assays and new assays are also described. This review demonstrates that there is ample research and intellectual space for future investigators to elucidate the role of chemotaxis in important processes such as pathogenesis, bioremediation, and the bioprotection of plants and animals.
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Affiliation(s)
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA, USA
| | - Tino Krell
- Department of Environmental Protection, CSIC, Estacion Experimental del Zaidin, Granada, Spain
| | - Jane E Hill
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
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Bacterial swimming, swarming and chemotactic response to heavy metal presence: which could be the influence on wastewater biotreatment efficiency? World J Microbiol Biotechnol 2012; 28:2813-25. [PMID: 22806721 DOI: 10.1007/s11274-012-1091-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 05/23/2012] [Indexed: 10/28/2022]
Abstract
Fixed-bed reactors are usually designed for wastewater biotreatments, where the biofilm establishment and maintenance play the most important roles. Biofilm development strictly relies on different types of bacterial motility: swimming, swarming, and chemotaxis, which can be altered by the microenvironment conditions. The aim of this work is to do an integrated study on the effects of Cu(II), Cd(II), Zn(II) and Cr(VI) on swimming, swarming and chemotaxis of Pseudomonas veronii 2E, Delftia acidovorans AR and Ralstonia taiwanensis M2 to improve biofilm development and maintenance for metal loaded wastewater biotreatment in fixed-bed bioreactors. Swimming, swarming and chemotactic response evaluation experiments were carried out at different metal concentrations. P. veronii 2E motility was not affected by metal presence, being this strain optimal for fixed-bed reactors. D. acidovorans AR swarming was inhibited by Cd and Zn. Although R. taiwanensis M2 showed high resistance to Cu, Cd, Cr and Zn, motility was definitively altered, so further studies on R. taiwanensis M2 resistance mechanisms would be particularly interesting.
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12
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Shitashiro M, Tanaka H, Hong CS, Kuroda A, Takiguchi N, Ohtake H, Kato J. Identification of chemosensory proteins for trichloroethylene in Pseudomonas aeruginosa. J Biosci Bioeng 2005; 99:396-402. [PMID: 16233808 DOI: 10.1263/jbb.99.396] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Accepted: 01/17/2005] [Indexed: 11/17/2022]
Abstract
The involvement of the chemotaxis gene cluster 1 (cheYZABW) and cheR in repellent responses of Pseudomonas aeruginosa to trichloroethylene (TCE) is described and three methyl-accepting chemotaxis proteins (MCPs) for TCE are identified. TCE chemotaxis assays of a number of deletion-insertion mutants of P. aeruginosa PAO1 revealed that the chemotaxis gene cluster 1 and cheR are required for negative chemotaxis to TCE. Mutant strains which contained deletions in pctA, pctB and pctC showed decreased responses to TCE. The pctA, pctB and pctC genes have been reported to encode MCPs for amino acids [K. Taguchi et al., Microbiology, 143, 3223--3229 (2000)]. The pctA mutation more severely impaired chemotactic responses to TCE than did those of pctB and pctC, suggesting that PctA is the major MCP for TCE among the three MCPs. The pctA, pctB and pctC mutant strains showed decreased responses to chloroform and methylthiocyanate. This result demonstrates that PctA, PctB and PctC are also involved in repellent responses to chloroform and methylthiocyanate.
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Affiliation(s)
- Maiko Shitashiro
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hioroshima, Hiroshima 739-8530, Japan
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13
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Hong CS, Kuroda A, Ikeda T, Takiguchi N, Ohtake H, Kato J. The aerotaxis transducer gene aer, but not aer-2, is transcriptionally regulated by the anaerobic regulator ANR in Pseudomonas aeruginosa. J Biosci Bioeng 2004; 97:184-90. [PMID: 16233612 DOI: 10.1016/s1389-1723(04)70188-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Accepted: 12/16/2003] [Indexed: 11/27/2022]
Abstract
The regulation of aerotaxis in Pseudomonas aeruginosa is reported. P. aeruginosa possesses two aerotaxis transducers, Aer and Aer-2. The aerotactic responses of P. aeruginosa cells were induced during the transition from exponential to stationary growth phase. A deletion mutant for the anaerobic transcriptional regulator ANR showed decreased aerotaxis. The anr mutation eliminated Aer-mediated aerotaxis, but not Aer-2-mediated aerotaxis. Expression of an aer-lacZ transcriptional fusion was also induced during the transition from exponential to stationary growth phase. The anr mutant showed only background levels of aer-lacZ expression. Rapid amplification of cDNA ends (RACE) and DNA sequencing revealed that the 5' end of the mRNA was located at an A nucleotide -67 nt upstream of aer. The aer promoter contained two putative FNR/ANR boxes at -42.5 and -93.5 bp upstream of the transcriptional start site of aer. Mutational analysis of the aer promoter region revealed that both FNR/ANR boxes were essential for the expression of the aer gene. These results indicate that ANR is required for the activation of aer expression but it is not essential for Aer-2-mediated aerotaxis in P. aeruginosa.
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Affiliation(s)
- Chang Soo Hong
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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14
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Abstract
Type IV pili are thin filaments that extend from the poles of a diverse group of bacteria, enabling them to move at speeds of a few tenths of a micrometer per second. They are required for twitching motility, e.g., in Pseudomonas aeruginosa and Neisseria gonorrhoeae, and for social gliding motility in Myxococcus xanthus. Here we report direct observation of extension and retraction of type IV pili in P. aeruginosa. Cells without flagellar filaments were labeled with an amino-specific Cy3 fluorescent dye and were visualized on a quartz slide by total internal reflection microscopy. When pili were attached to a cell and their distal ends were free, they extended or retracted at rates of about 0.5 microm s(-1) (29 degrees C). They also flexed by Brownian motion, exhibiting a persistence length of about 5 microm. Frequently, the distal tip of a filament adsorbed to the substratum and the filament was pulled taut. From the absence of lateral deflections of such filaments, we estimate tensions of at least 10 pN. Occasionally, cell bodies came free and were pulled forward by pilus retraction. Thus, type IV pili are linear actuators that extend, attach at their distal tips, exert substantial force, and retract.
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Affiliation(s)
- J M Skerker
- Rowland Institute for Science, Cambridge, MA 02142, USA
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15
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Déziel E, Comeau Y, Villemur R. Initiation of biofilm formation by Pseudomonas aeruginosa 57RP correlates with emergence of hyperpiliated and highly adherent phenotypic variants deficient in swimming, swarming, and twitching motilities. J Bacteriol 2001; 183:1195-204. [PMID: 11157931 PMCID: PMC94992 DOI: 10.1128/jb.183.4.1195-1204.2001] [Citation(s) in RCA: 315] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous environmental bacterium capable of forming biofilms on surfaces as a survival strategy. It exhibits a large variety of competition/virulence factors, such as three types of motilities: flagellum-mediated swimming, flagellum-mediated swarming, and type IV pilus-mediated twitching. A strategy frequently used by bacteria to survive changing environmental conditions is to create a phenotypically heterogeneous population by a mechanism called phase variation. In this report, we describe the characterization of phenotypic variants forming small, rough colonies that spontaneously emerged when P. aeruginosa 57RP was cultivated as a biofilm or in static liquid cultures. These small-colony (S) variants produced abundant type IV fimbriae, displayed defective swimming, swarming, and twitching motilities, and were impaired in chemotaxis. They also autoaggregated in liquid cultures and rapidly initiated the formation of strongly adherent biofilms. In contrast, the large-colony variant (parent form) was poorly adherent, homogeneously dispersed in liquid cultures, and produced scant polar fimbriae. Further analysis of the S variants demonstrated differences in a variety of other phenotypic traits, including increased production of pyocyanin and pyoverdine and reduced elastase activity. Under appropriate growth conditions, cells of each phenotype switched to the other phenotype at a fairly high frequency. We conclude that these S variants resulted from phase variation and were selectively enriched when P. aeruginosa 57RP was grown as a biofilm or in static liquid cultures. We propose that phase variation ensures the prior presence of phenotypic forms well adapted to initiate the formation of a biofilm as soon as environmental conditions are favorable.
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Affiliation(s)
- E Déziel
- INRS-Institut Armand-Frappier-Microbiologie et Biotechnologie, Laval, Québec, Canada H7V 1B7
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16
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Lu CD, Abdelal AT. The gdhB gene of Pseudomonas aeruginosa encodes an arginine-inducible NAD(+)-dependent glutamate dehydrogenase which is subject to allosteric regulation. J Bacteriol 2001; 183:490-9. [PMID: 11133942 PMCID: PMC94904 DOI: 10.1128/jb.183.2.490-499.2001] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The NAD(+)-dependent glutamate dehydrogenase (NAD-GDH) from Pseudomonas aeruginosa PAO1 was purified, and its amino-terminal amino acid sequence was determined. This sequence information was used in identifying and cloning the encoding gdhB gene and its flanking regions. The molecular mass predicted from the derived sequence for the encoded NAD-GDH was 182.6 kDa, in close agreement with that determined from sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme (180 kDa). Cross-linking studies established that the native NAD-GDH is a tetramer of equal subunits. Comparison of the derived amino acid sequence of NAD-GDH from P. aeruginosa with the GenBank database showed the highest homology with hypothetical polypeptides from Pseudomonas putida, Mycobacterium tuberculosis, Rickettsia prowazakii, Legionella pneumophila, Vibrio cholerae, Shewanella putrefaciens, Sinorhizobium meliloti, and Caulobacter crescentus. A moderate degree of homology, primarily in the central domain, was observed with the smaller tetrameric NAD-GDH (protomeric mass of 110 kDa) from Saccharomyces cerevisiae or Neurospora crassa. Comparison with the yet smaller hexameric GDH (protomeric mass of 48 to 55 kDa) of other prokaryotes yielded a low degree of homology that was limited to residues important for binding of substrates and for catalytic function. NAD-GDH was induced 27-fold by exogenous arginine and only 3-fold by exogenous glutamate. Primer extension experiments established that transcription of gdhB is initiated from an arginine-inducible promoter and that this induction is dependent on the arginine regulatory protein, ArgR, a member of the AraC/XyIS family of regulatory proteins. NAD-GDH was purified to homogeneity from a recombinant strain of P. aeruginosa and characterized. The glutamate saturation curve was sigmoid, indicating positive cooperativity in the binding of glutamate. NAD-GDH activity was subject to allosteric control by arginine and citrate, which function as positive and negative effectors, respectively. Both effectors act by influencing the affinity of the enzyme for glutamate. NAD-GDH from this organism differs from previously characterized enzymes with respect to structure, protomer mass, and allosteric properties indicate that this enzyme represents a novel class of microbial glutamate dehydrogenases.
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Affiliation(s)
- C D Lu
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA
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17
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Köhler T, Curty LK, Barja F, van Delden C, Pechère JC. Swarming of Pseudomonas aeruginosa is dependent on cell-to-cell signaling and requires flagella and pili. J Bacteriol 2000; 182:5990-6. [PMID: 11029417 PMCID: PMC94731 DOI: 10.1128/jb.182.21.5990-5996.2000] [Citation(s) in RCA: 592] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe swarming in Pseudomonas aeruginosa as a third mode of surface translocation in addition to the previously described swimming and twitching motilities. Swarming in P. aeruginosa is induced on semisolid surfaces (0.5 to 0.7% agar) under conditions of nitrogen limitation and in response to certain amino acids. Glutamate, aspartate, histidine, or proline, when provided as the sole source of nitrogen, induced swarming, while arginine, asparagine, and glutamine, among other amino acids, did not sustain swarming. Cells from the edge of the swarm were about twice as long as cells from the swarm center. In both instances, bacteria possessing two polar flagella were observed by light and electron microscopy. While a fliC mutant of P. aeruginosa displayed slightly diminished swarming, a pilR and a pilA mutant, both deficient in type IV pili, were unable to swarm. Furthermore, cells with mutations in the las cell-to-cell signaling system showed diminished swarming behavior, while rhl mutants were completely unable to swarm. Evidence is presented for rhamnolipids being the actual surfactant involved in swarming motility, which explains the involvement of the cell-to-cell signaling circuitry of P. aeruginosa in this type of surface motility.
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Affiliation(s)
- T Köhler
- Department of Genetics and Microbiology, University Medical Center, Sciences III, University of Geneva, CH-1211 Geneva 4, Switzerland.
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18
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Mazumder R, Phelps TJ, Krieg NR, Benoit RE. Determining chemotactic responses by two subsurface microaerophiles using a simplified capillary assay method. J Microbiol Methods 1999; 37:255-63. [PMID: 10480269 DOI: 10.1016/s0167-7012(99)00072-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A simplified capillary chemotaxis assay utilizing a hypodermic needle, syringe, and disposable pipette tip was developed to measure bacterial tactic responses. The method was applied to two strains of subsurface microaerophilic bacteria. This method was more convenient than the Adler method and required less practice. Isolate VT10 was a strain of Pseudomonas syringae, which was isolated from the shallow subsurface. It was chemotactically attracted toward dextrose, glycerol, and phenol, which could be used as sole carbon sources, and toward maltose, which could not be used. Isolate MR100 was phylogenetically related to Pseudomonas mendocina and was isolated from the deep subsurface. It showed no tactic response to these compounds, although, it could use dextrose, maltose, and glycerol as carbon sources. The chemotaxis results obtained by the new method were verified by using the swarm plate assay technique. The simplified technique may be useful for routine chemotactic testing.
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Affiliation(s)
- R Mazumder
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA
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19
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Nishijyo T, Park SM, Lu CD, Itoh Y, Abdelal AT. Molecular characterization and regulation of an operon encoding a system for transport of arginine and ornithine and the ArgR regulatory protein in Pseudomonas aeruginosa. J Bacteriol 1998; 180:5559-66. [PMID: 9791103 PMCID: PMC107612 DOI: 10.1128/jb.180.21.5559-5566.1998] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The complete nucleotide sequence for the aot operon of Pseudomonas aeruginosa PAO1 was determined. This operon contains six open reading frames. The derived sequences for four of these, aotJ, aotQ, aotM, and aotP, show high similarity to those of components of the periplasmic binding protein-dependent ABC (ATP binding cassette) transporters of enteric bacteria. Transport studies with deletion derivatives established that these four genes function in arginine-inducible uptake of arginine and ornithine but not lysine. The aotO gene, which encodes a polypeptide with no significant similarity to any known proteins, is not essential for arginine and ornithine uptake. The sixth and terminal gene in the operon encodes ArgR, which has been recently shown to function in regulation of arginine metabolism. Studies with an aotJ::lacZ translational fusion showed that expression of the aot operon is strongly induced by arginine and that this effect is mediated by ArgR. S1 nuclease and primer extension experiments showed the presence of two promoters, P1 and P2. The downstream promoter, P2, is induced by arginine and appears to be subject to carbon catabolite repression. The upstream promoter, P1, is induced by glutamate. Footprinting experiments established the presence of a 44-bp ArgR binding site that overlaps the -35 region for P2, as was shown to be the case for the arginine-inducible aru promoter, and the -10 region for P1, as was shown to be the case for arginine-repressible operons in P. aeruginosa. Sequence alignment confirms the architecture and the consensus sequence of the ArgR binding sites, as was previously reported.
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Affiliation(s)
- T Nishijyo
- National Food Research Institute, Tsukuba, Ibaraki 305, Japan
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20
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Tuhela L, Robinson JB, Tuovinen OH. Characterization of chemotactic responses and flagella of Hyphomicrobium strain W1-1B. J Bacteriol 1998; 180:3003-6. [PMID: 9603896 PMCID: PMC107273 DOI: 10.1128/jb.180.11.3003-3006.1998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Motile swarmer cells of Hyphomicrobium strain W1-1B displayed positive chemotactic responses toward methylamine, dimethylamine, and trimethylamine but did not display significant chemotactic responses towards methanol and arginine. Electron micrographs of negatively stained intact flagellar filaments indicated a novel striated surface pattern. The flagella were composed of two proteins of 39 and 41 kDa. Neither protein was a glycoprotein as determined by Schiff's staining and by enzyme immunoassay. Protein fingerprints visualized from silver-stained polyacrylamide gels and Western blots of protease-digested samples indicated that the two proteins were similar but not identical. Monoclonal antibodies prepared to the complex flagella of Rhizobium meliloti cross-reacted with the striated flagella of Hyphomicrobium strain W1-1B; however, these antibodies did not cross-react with smooth-surface flagella. These results suggest that complex and striated flagella possess homologous epitope regions.
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Affiliation(s)
- L Tuhela
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210-1292, USA
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21
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Taguchi K, Fukutomi H, Kuroda A, Kato J, Ohtake H. Genetic identification of chemotactic transducers for amino acids in Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 10):3223-3229. [PMID: 9353923 DOI: 10.1099/00221287-143-10-3223] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two chemotactic transducer genes (termed pctB and pctC) and an open reading frame (orf1) were found in the pctA-flanking region which was previously identified as a chemotactic transducer gene in Pseudomonas aeruginosa. The pctB and pctC genes encode predicted polypeptides of 629 and 632 amino acids, respectively. Overall, PctB and PctC had 81 and 75% amino acid identities with PctA, respectively. A null mutant strain PCT2, which contained a deletion in the entire pctC, orf1, pctA and pctB genes, did not show chemotaxis towards all 20 commonly occurring L-amino acids. This mutant strain also failed to respond to amino acid catabolites (cadaverine, 4-aminobutyrate and putrescine) that are strong attractants for the wild-type strain PAO1. To study the role of each gene product in L-amino acid taxis, plasmids harbouring the pctC, orf1, pctA, or pctB genes were constructed and introduced into strain PCT2 by transformation. The orf1 gene did not complement the defect in chemotaxis of strain PCT2. The pctA gene restored the ability of strain PCT2 to respond to 18 L-amino acids, suggesting that PctA plays a major role in detecting L-amino acids in P. aeruginosa. The pctB and pctC genes complemented the defect in chemotaxis to only seven (Ala, Arg, Glu, Lys, Met, Tyr, Gln) and two (His, Pro) L-amino acids, respectively.
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Affiliation(s)
- Kazunori Taguchi
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739, Japan
| | - Hiroyuki Fukutomi
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739, Japan
| | - Akio Kuroda
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739, Japan
| | - Junichi Kato
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739, Japan
| | - Hisao Ohtake
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739, Japan
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22
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Park SM, Lu CD, Abdelal AT. Cloning and characterization of argR, a gene that participates in regulation of arginine biosynthesis and catabolism in Pseudomonas aeruginosa PAO1. J Bacteriol 1997; 179:5300-8. [PMID: 9286980 PMCID: PMC179396 DOI: 10.1128/jb.179.17.5300-5308.1997] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Gel retardation experiments indicated the presence in Pseudomonas aeruginosa cell extracts of an arginine-inducible DNA-binding protein that interacts with the control regions for the car and argF operons, encoding carbamoylphosphate synthetase and anabolic ornithine carbamoyltransferase, respectively. Both enzymes are required for arginine biosynthesis. The use of a combination of transposon mutagenesis and arginine hydroxamate selection led to the isolation of a regulatory mutant that was impaired in the formation of the DNA-binding protein and in which the expression of an argF::lacZ fusion was not controlled by arginine. Experiments with various subclones led to the conclusion that the insertion affected the expression of an arginine regulatory gene, argR, that encodes a polypeptide with significant homology to the AraC/XylS family of regulatory proteins. Determination of the nucleotide sequence of the flanking regions showed that argR is the sixth and terminal gene of an operon for transport of arginine. The argR gene was inactivated by gene replacement, using a gentamicin cassette. Inactivation of argR abolished arginine control of the biosynthetic enzymes encoded by the car and argF operons. Furthermore, argR inactivation abolished the induction of several enzymes of the arginine succinyltransferase pathway, which is considered the major route for arginine catabolism under aerobic conditions. Consistent with this finding and unlike the parent strain, the argR::Gm derivative was unable to utilize arginine or ornithine as the sole carbon source. The combined data indicate a major role for ArgR in the control of arginine biosynthesis and aerobic catabolism.
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Affiliation(s)
- S M Park
- Department of Biology, Georgia State University, Atlanta 30303, USA
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23
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Fischer RS, Song J, Gu W, Jensen RA. L-Arogenate Is a Chemoattractant Which Can Be Utilized as the Sole Source of Carbon and Nitrogen by Pseudomonas aeruginosa. Appl Environ Microbiol 1997; 63:567-73. [PMID: 16535513 PMCID: PMC1389519 DOI: 10.1128/aem.63.2.567-573.1997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
L-Arogenate is a commonplace amino acid in nature in consideration of its role as a ubiquitous precursor of L-phenylalanine and/or L-tyrosine. However, the questions of whether it serves as a chemoattractant molecule and whether it can serve as a substrate for catabolism have never been studied. We found that Pseudomonas aeruginosa recognizes L-arogenate as a chemoattractant molecule which can be utilized as a source of both carbon and nitrogen. Mutants lacking expression of either cyclohexadienyl dehydratase or phenylalanine hydroxylase exhibited highly reduced growth rates when utilizing L-arogenate as a nitrogen source. Utilization of L-arogenate as a source of either carbon or nitrogen was dependent upon (sigma)(sup54), as revealed by the use of an rpoN null mutant. The evidence suggests that catabolism of L-arogenate proceeds via alternative pathways which converge at 4-hydroxyphenylpyruvate. In one pathway, prephenate formed in the periplasm by deamination of L-arogenate is converted to 4-hydroxyphenylpyruvate by cyclohexadienyl dehydrogenase. The second route depends upon the sequential action of periplasmic cyclohexadienyl dehydratase, phenylalanine hydroxylase, and aromatic aminotransferase.
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24
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Abstract
Three phenolic acids, p-coumaric acid, ferulic acid and syringic acid, were evaluated as chemoattractants for zoospores of two monocentric and two polycentric isolates of anaerobic, zoosporic ruminal fungi. Attraction of fungal zoospores to the acids was determined by a modification of the Palleroni method and fungal thallus forming units were counted after incubating capillary tubes in a chemotaxis chamber. Chemotactic response was expressed as relative taxis response (RTR), which is the ratio of accumulation of zoospores in test capillaries to that in control capillaries. Monocentric isolates had greater RTR values then did the polycentric isolates. The order of chemoattraction for the uniflagellate isolates was p-coumaric acid > ferulic acid > syringic acid. The order of attraction was different between the two isolates with multiflagellate zoospores. Ferulic acid and p-coumaric acid were better chemoattractants than syringic acid. Peak response for the monocentric isolates was 1.0 mumol l-1 while that for the polycentric isolates was 0.1 mmol l-1.
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Affiliation(s)
- D A Wubah
- Towson State University, Department of Biological Sciences, MD 21204, USA
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25
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Kuroda A, Kumano T, Taguchi K, Nikata T, Kato J, Ohtake H. Molecular cloning and characterization of a chemotactic transducer gene in Pseudomonas aeruginosa. J Bacteriol 1995; 177:7019-25. [PMID: 8522505 PMCID: PMC177577 DOI: 10.1128/jb.177.24.7019-7025.1995] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A Pseudomonas aeruginosa mutant, defective in taxis toward L-serine but responsive to peptone, was selected by the swarm plate method after N-methyl-N'-nitrosoguanidine mutagenesis. The mutant, designated PCT1, was fully motile but failed to show chemotactic responses to glycine, L-serine, L-threonine, and L-valine. PCT1 also showed weaker responses to some other commonly occurring L-amino acids than did the wild-type strain PAO1. A chemotactic transducer gene, denoted pctA (Pseudomonas chemotactic transducer A), was cloned by phenotypic complementation of PCT1. Nucleotide sequence analysis showed that the pctA gene encodes a putative polypeptide of 629 amino acids with a calculated mass of 68,042. A hydropathy plot of the predicted polypeptide suggested that PctA may be an integral membrane protein with two potential membrane-spanning regions. The C-terminal domain of PctA showed high homology with the enteric methyl-accepting chemotaxis proteins (MCPs). The most significant amino acid sequence similarity was found in the region of MCPs referred to as the highly conserved domain. The pctA gene was inactivated by insertion of a kanamycin resistance gene cassette into the wild-type gene, resulting in the same observed deficiency in taxis toward L-amino acids as PCT1. In vivo methyl labeling experiments with L-[methyl-3H]methionine showed that this knockout mutant lacked an MCP with a molecular weight of approximately 68,000.
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Affiliation(s)
- A Kuroda
- Department of Fermentation Technology, Hiroshima University, Japan
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26
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Masduki A, Nakamura J, Ohga T, Umezaki R, Kato J, Ohtake H. Isolation and characterization of chemotaxis mutants and genes of Pseudomonas aeruginosa. J Bacteriol 1995; 177:948-52. [PMID: 7860605 PMCID: PMC176688 DOI: 10.1128/jb.177.4.948-952.1995] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Two chemotaxis-defective mutants of Pseudomonas aeruginosa, designated PC1 and PC2, were selected by the swarm plate method after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. These mutants were fully motile but incapable of swarming, suggesting that they had a defect in the intracellular signalling pathway. Computer-assisted capillary assays confirmed that they failed to show behavioral responses to chemical stimuli, including peptone, methyl thiocyanate, and phosphate. Two chemotaxis genes were cloned by phenotypic complementation of PC1 and PC2. From nucleotide sequence analysis, one gene was found to encode a putative polypeptide that was homologous to the enteric CheZ protein, while the other gene was cheY, which had been previously reported (M. N. Starnbach and S. Lory, Mol. Microbiol. 6:459-469, 1992). Deletion and complementation analysis showed that PC1 was a cheY mutant, whereas PC2 had a double mutation in the cheY and cheZ genes. A chromosomal cheZ mutant, constructed by inserting a kanamycin resistance gene cassette into the wild-type gene, changed its swimming direction much more frequently than did wild-type strain PAO1. In contrast, cheY mutants were found to rarely reverse their swimming directions.
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Affiliation(s)
- A Masduki
- Department of Fermentation Technology, Hiroshima University, Higashi-Hiroshima, Japan
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27
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Abstract
A number of peptides were evaluated as chemoattractants for Pseudomonas aeruginosa. Several strains recognized tri-, tetra-, penta-, and hexapeptides in a capillary tube assay. Tripeptides altered at the carboxyl terminus were good attractants, whereas tripeptides altered at the amino terminus did not serve as chemoattractants. Methionine-containing peptides were relatively poor attractants. Arginine-containing peptides gave the best responses. Reduced responses to larger peptides suggest that porin penetration is required. No extracellular peptidase activity was detected. We conclude that oligopeptides are good attractants and that specificity for chemotactic recognition of oligopeptides exists.
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Affiliation(s)
- K Kelly-Wintenberg
- Department of Microbiology, University of Tennessee, Knoxville 37996-0856
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28
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Abstract
Pseudomonas aeruginosa was shown to be attracted to phosphate. The chemotactic response was induced by phosphate starvation. The specificity of chemoreceptors for phosphate was high so that no other tested phosphorus compounds elicited a chemotactic response as strong as that elicited by phosphate. Competition experiments showed that the chemoreceptors for phosphate appeared to be different from those for the common amino acids. Mutants constitutive for alkaline phosphatase showed the chemotactic response to phosphate regardless of whether the cells were starved for phosphate.
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Affiliation(s)
- J Kato
- Department of Fermentation Technology, Hiroshima University, Japan
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29
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Kelly-Wintenberg K, Anderson T, Montie TC. Phosphorylated tyrosine in the flagellum filament protein of Pseudomonas aeruginosa. J Bacteriol 1990; 172:5135-9. [PMID: 1697577 PMCID: PMC213172 DOI: 10.1128/jb.172.9.5135-5139.1990] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Purified flagella from two strains of 32P-labeled Pseudomonas aeruginosa were shown to be phosphorylated. This was confirmed by autoradiography of flagellin protein in polyacrylamide gels. Thin-layer electrophoresis and autoradiography of flagellin partial hydrolysates indicated that phosphotyrosine was the major phosphorylated amino acid. High-pressure liquid chromatographic analysis confirmed the presence of phosphotyrosine in flagellum filament protein. Preliminary data indicated that less than one tyrosine per subunit was phosphorylated. No evidence was found for phosphorylation of serine or threonine. A function related to tyrosine phosphorylation has not been determined.
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