1
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Dias D, Fonseca C, Mendo S, Caetano T. First characterization of the faecal resistome of eurasian otter (Lutra lutra), a sentinel species for aquatic environments. CHEMOSPHERE 2022; 309:136644. [PMID: 36181859 DOI: 10.1016/j.chemosphere.2022.136644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 09/17/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Antimicrobial resistance (AMR) is a global health concern. Nowadays, antibiotic resistance genes (ARGs) are considered emerging pollutants. This study followed the One Health framework, in which AMR surveillance in the environment, including in wild animals, is advisable to mitigate this problem. Here we investigated AMR associated with Eurasian otter, a semi-aquatic mammal considered an indicator of freshwater health. To do so, otter's faecal resistome was characterized by a high-throughput qPCR array. This technique has a high-capacity of ARGs profiling. Additionally, we have assessed the antimicrobial susceptibility of two indicator bacteria, E. coli and Enterococcus spp, isolated from otter spraints and interpreted the results according to clinical and epidemiological cut-offs (ECOFFs).
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Affiliation(s)
- Diana Dias
- CESAM and Department of Biology, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Carlos Fonseca
- CESAM and Department of Biology, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal; ForestWISE - Collaborative Laboratory for Integrated Forest & Fire Management, Quinta de Prados, 5001-801, Vila Real, Portugal
| | - Sónia Mendo
- CESAM and Department of Biology, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Tânia Caetano
- CESAM and Department of Biology, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
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2
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Hu J, Wang D, Huang X, Yang Y, Lian X, Wang W, Xu X, Liu Y. Effects of TolC on the pathogenicity of porcine extraintestinal pathogenic Escherichia coli. Front Immunol 2022; 13:929740. [PMID: 36059454 PMCID: PMC9433895 DOI: 10.3389/fimmu.2022.929740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/27/2022] [Indexed: 11/25/2022] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is a well-known critical pathogenic zoonosis that causes extraintestinal infections in humans and animals by affecting their immune organs. Recently, research on the outer membrane protein of E. coli, tolerant colicin (TolC), a virulent protein in the formation of the ExPEC efflux pump, has been an attractive subject. However, the pathogenic mechanisms remain unclear. This study aimed to explore the role of TolC in the pathogenesis of the ExPEC strain PPECC42; a complementation strain (Cm-TolC) and an isogenic mutant (ΔTolC) were constructed. Loss of TolC drastically impaired the virulence of ExPEC in an experimental mouse model. ΔTolC showed a substantial decrease in the porcine aortic vascular endothelial cell (PAVEC) adherence, invasion, and pro-inflammatory response, in contrast to that of the wild type, with a reduced survival ratio in both the bacterial load and whole blood in mice. ΔTolC also showed decreased expression of necroptosis signals such as receptor-interacting protein kinase 1, phosphorylated mixed-lineage kinase domain-like protein, and mitochondrial proteins such as phosphoglycerate mutase family member 5. Our data suggest that TolC is closely associated with ExPEC pathogenesis. These results provide scientific grounds for exploring the potential of TolC as an effective drug target for controlling ExPEC infection, screening new inhibitors, and developing new drugs. This will allow for further prevention and control of ExPEC infection.
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Affiliation(s)
- Jin Hu
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Dongfang Wang
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Xingfa Huang
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
- Hubei Provincial Key Laboratory for Protection and Application of Special Plants in Wuling Area of China, South-Central University for Nationalities, Wuhan, China
| | - Yang Yang
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Xin Lian
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Wenjun Wang
- Hubei Provincial Key Laboratory for Protection and Application of Special Plants in Wuling Area of China, South-Central University for Nationalities, Wuhan, China
| | - Xiao Xu
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Yulan Liu
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
- *Correspondence: Yulan Liu,
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3
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Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:microorganisms10061239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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4
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Polmickaitė-Smirnova E, Buchovec I, Bagdonas S, Sužiedėlienė E, Ramanavičius A, Anusevičius Ž. Photoinactivation of Salmonella enterica exposed to 5-aminolevulinic acid: Impact of sensitization conditions and irradiation time. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 231:112446. [PMID: 35487120 DOI: 10.1016/j.jphotobiol.2022.112446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 03/25/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
The photodynamic inactivation (PDI) represents the potential alternative to traditional antibiotic therapy, and can be applied to treat various bacterial infections, including those caused by Gram-negative bacterial strains. One of the treatment modalities is based on the capacity of bacterial cells to synthesize the excess amounts of porphyrins after exposure to an externally applied 5-aminolevulinic acid (5-ALA), which makes them photosensitive and leads to reduced survival after irradiation with an appropriately selected light source. This study focuses on the sensitization and the photoinduced inactivation of Salmonella enterica cells in PBS containing 0.5 mM 5-ALA, incubated at 37 °C for 4 h or for 20 h and afterwards irradiated with violet LED light (11.1 mW/cm2, a peak at 400 nm). It has been found that both amounts and composition of endogenous porphyrins not only depended on the incubation duration, but also were affected by externally induced photo- and chemo-oxidation reactions. The application of different sensitization conditions has revealed that the increasing amounts of endogenously produced porphyrins do not ensure the proportional reduction of bacterial cell survival numbers. The comparative investigations also demonstrated that the presence of endogenously produced porphyrins in the medium results in secondary sensitization of bacterial cells and causes a notably stronger photoinactivation effect in comparison to their externally applied standards.
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Affiliation(s)
- Evelina Polmickaitė-Smirnova
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania.
| | - Irina Buchovec
- Institute of Photonics and Nanotechnology, Faculty of Physics, Vilnius University, Saulėtekio av. 3, LT-10257 Vilnius, Lithuania
| | - Saulius Bagdonas
- Laser Research Center, Faculty of Physics, Vilnius University, Saulėtekio av. 9, LT-10222 Vilnius, Lithuania
| | - Edita Sužiedėlienė
- Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Arūnas Ramanavičius
- Department of Physical Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko str. 24, LT-03225 Vilnius, Lithuania
| | - Žilvinas Anusevičius
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
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5
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Rapacka-Zdonczyk A, Wozniak A, Kruszewska B, Waleron K, Grinholc M. Can Gram-Negative Bacteria Develop Resistance to Antimicrobial Blue Light Treatment? Int J Mol Sci 2021; 22:ijms222111579. [PMID: 34769009 PMCID: PMC8583887 DOI: 10.3390/ijms222111579] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/18/2021] [Accepted: 10/24/2021] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial blue light (aBL) treatment is considered low risk for the development of bacterial resistance and tolerance due to its multitarget mode of action. The aim of the current study was to demonstrate whether tolerance development occurs in Gram-negative bacteria. We evaluated the potential of tolerance/resistance development in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and demonstrated that representative Gram-negative bacteria may develop tolerance to aBL. The observed adaption was a stable feature. Assays involving E. coli K-12 tolC-, tolA-, umuD-, and recA-deficient mutants revealed some possible mechanisms for aBL tolerance development.
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Affiliation(s)
- Aleksandra Rapacka-Zdonczyk
- Department of Pharmaceutical Microbiology, The Faculty of Pharmacy, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland; (B.K.); (K.W.)
- Correspondence:
| | - Agata Wozniak
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland; (A.W.); (M.G.)
| | - Beata Kruszewska
- Department of Pharmaceutical Microbiology, The Faculty of Pharmacy, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland; (B.K.); (K.W.)
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland; (A.W.); (M.G.)
| | - Krzysztof Waleron
- Department of Pharmaceutical Microbiology, The Faculty of Pharmacy, Medical University of Gdansk, Hallera 107, 80-416 Gdansk, Poland; (B.K.); (K.W.)
| | - Mariusz Grinholc
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland; (A.W.); (M.G.)
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6
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Sułek A, Pucelik B, Kobielusz M, Barzowska A, Dąbrowski JM. Photodynamic Inactivation of Bacteria with Porphyrin Derivatives: Effect of Charge, Lipophilicity, ROS Generation, and Cellular Uptake on Their Biological Activity In Vitro. Int J Mol Sci 2020; 21:ijms21228716. [PMID: 33218103 PMCID: PMC7698881 DOI: 10.3390/ijms21228716] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/31/2022] Open
Abstract
Resistance of microorganisms to antibiotics has led to research on various therapeutic strategies with different mechanisms of action, including photodynamic inactivation (PDI). In this work, we evaluated a cationic, neutral, and anionic meso-tetraphenylporphyrin derivative’s ability to inactivate the Gram-negative and Gram-positive bacteria in a planktonic suspension under blue light irradiation. The spectroscopic, physicochemical, redox properties, as well as reactive oxygen species (ROS) generation capacity by a set of photosensitizers varying in lipophilicity were investigated. The theoretical calculations were performed to explain the distribution of the molecular charges in the evaluated compounds. Moreover, logP partition coefficients, cellular uptake, and phototoxicity of the photosensitizers towards bacteria were determined. The role of a specific microbial efflux pump inhibitor, verapamil hydrochloride, in PDI was also studied. The results showed that E. coli exhibited higher resistance to PDI than S. aureus (3–5 logs) with low light doses (1–10 J/cm2). In turn, the prolongation of irradiation (up to 100 J/cm2) remarkably improved the inactivation of pathogens (up to 7 logs) and revealed the importance of photosensitizer photostability. The PDI potentiation occurs after the addition of KI (more than 3 logs extra killing). Verapamil increased the uptake of photosensitizers (especially in E. coli) due to efflux pump inhibition. This effect suggests that PDI is mediated by ROS, the electrostatic charge interaction, and the efflux of photosensitizers (PSs) regulated by multidrug-resistance (MDR) systems. Thus, MDR inhibition combined with PDI gives opportunities to treat more resistant bacteria.
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Affiliation(s)
- Adam Sułek
- Faculty of Chemistry, Jagiellonian University, 30-387 Krakow, Poland; (A.S.); (M.K.)
| | - Barbara Pucelik
- Małopolska Center of Biotechnology, Jagiellonian University, 30-387 Krakow, Poland; (B.P.); (A.B.)
| | - Marcin Kobielusz
- Faculty of Chemistry, Jagiellonian University, 30-387 Krakow, Poland; (A.S.); (M.K.)
| | - Agata Barzowska
- Małopolska Center of Biotechnology, Jagiellonian University, 30-387 Krakow, Poland; (B.P.); (A.B.)
| | - Janusz M. Dąbrowski
- Faculty of Chemistry, Jagiellonian University, 30-387 Krakow, Poland; (A.S.); (M.K.)
- Correspondence: ; Tel.: +48-12-686-2488; Fax: +48-12-686-2750
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7
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Bruckbauer ST, Martin J, Minkoff BB, Veling MT, Lancaster I, Liu J, Trimarco JD, Bushnell B, Lipzen A, Wood EA, Sussman MR, Pennacchio C, Cox MM. Physiology of Highly Radioresistant Escherichia coli After Experimental Evolution for 100 Cycles of Selection. Front Microbiol 2020; 11:582590. [PMID: 33072055 PMCID: PMC7536353 DOI: 10.3389/fmicb.2020.582590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/26/2020] [Indexed: 11/13/2022] Open
Abstract
Ionizing radiation (IR) is lethal to most organisms at high doses, damaging every cellular macromolecule via induction of reactive oxygen species (ROS). Utilizing experimental evolution and continuing previous work, we have generated the most IR-resistant Escherichia coli populations developed to date. After 100 cycles of selection, the dose required to kill 99% the four replicate populations (IR9-100, IR10-100, IR11-100, and IR12-100) has increased from 750 Gy to approximately 3,000 Gy. Fitness trade-offs, specialization, and clonal interference are evident. Long-lived competing sub-populations are present in three of the four lineages. In IR9, one lineage accumulates the heme precursor, porphyrin, leading to generation of yellow-brown colonies. Major genomic alterations are present. IR9 and IR10 exhibit major deletions and/or duplications proximal to the chromosome replication terminus. Contributions to IR resistance have expanded beyond the alterations in DNA repair systems documented previously. Variants of proteins involved in ATP synthesis (AtpA), iron-sulfur cluster biogenesis (SufD) and cadaverine synthesis (CadA) each contribute to IR resistance in IR9-100. Major genomic and physiological changes are emerging. An isolate from IR10 exhibits protein protection from ROS similar to the extremely radiation resistant bacterium Deinococcus radiodurans, without evident changes in cellular metal homeostasis. Selection is continuing with no limit to IR resistance in evidence as our E. coli populations approach levels of IR resistance typical of D. radiodurans.
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Affiliation(s)
- Steven T Bruckbauer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Joel Martin
- DOE Joint Genome Institute, Berkeley, CA, United States
| | - Benjamin B Minkoff
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States.,Center for Genomic Science Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Mike T Veling
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
| | - Illissa Lancaster
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Jessica Liu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph D Trimarco
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Anna Lipzen
- DOE Joint Genome Institute, Berkeley, CA, United States
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Michael R Sussman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States.,Center for Genomic Science Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | | | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
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8
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RNase E-dependent degradation of tnaA mRNA encoding tryptophanase is prerequisite for the induction of acid resistance in Escherichia coli. Sci Rep 2020; 10:7128. [PMID: 32346014 PMCID: PMC7188888 DOI: 10.1038/s41598-020-63981-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 04/09/2020] [Indexed: 01/25/2023] Open
Abstract
Acid-resistance systems are essential for pathogenic Escherichia coli to survive in the strongly acidic environment of the human stomach (pH < 2.5). Among these, the glutamic acid decarboxylase (GAD) system is the most effective. However, the precise mechanism of GAD induction is unknown. We previously reported that a tolC mutant lacking the TolC outer membrane channel was defective in GAD induction. Here, we show that indole, a substrate of TolC-dependent efflux pumps and produced by the tryptophanase encoded by the tnaA gene, negatively regulates GAD expression. GAD expression was restored by deleting tnaA in the tolC mutant; in wild-type E. coli, it was suppressed by adding indole to the growth medium. RNA-sequencing revealed that tnaA mRNA levels drastically decreased upon exposure to moderately acidic conditions (pH 5.5). This decrease was suppressed by RNase E deficiency. Collectively, our results demonstrate that the RNase E-dependent degradation of tnaA mRNA is accelerated upon acid exposure, which decreases intracellular indole concentrations and triggers GAD induction.
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9
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Guest RL, Court EA, Waldon JL, Schock KA, Raivio TL. Impaired Efflux of the Siderophore Enterobactin Induces Envelope Stress in Escherichia coli. Front Microbiol 2019; 10:2776. [PMID: 31866967 PMCID: PMC6908949 DOI: 10.3389/fmicb.2019.02776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/14/2019] [Indexed: 01/04/2023] Open
Abstract
The Cpx response is one of several envelope stress responses that monitor and maintain the integrity of the gram-negative bacterial envelope. While several conditions that are known or predicted to generate misfolded inner membrane proteins activate the Cpx response, the molecular nature of the Cpx inducing cue is not yet known. Studies have demonstrated that mutation of multidrug efflux pumps activates the Cpx response in many gram-negative bacteria. In Vibrio cholerae, pathway activation is due to accumulation of the catechol siderophore vibriobactin. However, the mechanism by which the Cpx response is activated by mutation of efflux pumps in Escherichia coli remains unknown. Here we show that inhibition of efflux by deletion of tolC, the outer membrane channel of several multidrug efflux pumps, activates the Cpx response in E. coli as a result of impaired efflux of the siderophore enterobactin. Enterobactin accumulation in the tolC mutant reduces activity of the nicotinamide adenine dinucleotide (NADH) oxidation arm of the aerobic respiratory chain. However, the Cpx pathway remains active in the tolC mutant when either NADH dehydrogenase I, NADH dehydrogenase II, or cytochrome bo3 is absent. Finally, we show that the Cpx response down-regulates transcription of the enterobactin biosynthesis operon. These results suggest that the Cpx response promotes adaptation to envelope stress in enteric bacteria that are exposed to iron-limited environments, which are rich in envelope-damaging compounds and conditions.
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Affiliation(s)
- Randi L Guest
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Emily A Court
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Jayne L Waldon
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Kiersten A Schock
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Tracy L Raivio
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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10
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Perez-Silva L, Sanchez-Vicente L, Molina-Alcaide E, Marin JJ, Herraez E. Evaluation of the promiscuous component of several bacterial export pumps TolC as a biomarker for toxic pollutants in feedstuffs. Chem Biol Interact 2019; 305:195-202. [DOI: 10.1016/j.cbi.2019.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/31/2019] [Accepted: 03/26/2019] [Indexed: 11/29/2022]
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11
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Polmickaitė-Smirnova E, Bagdonas S, Anusevičius Ž. Sensitization of Salmonella enterica with 5-aminolevulinic acid-induced endogenous porphyrins: a spectroscopic study. Photochem Photobiol Sci 2019; 18:2730-2739. [DOI: 10.1039/c9pp00200f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fluorescence spectroscopy data reflecting time-dependent changes in the type and localization of endogenous porphyrins reveal the sensitization potential of a precursor 5-ALA for Gram-negative foodborne pathogen Salmonella enterica.
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Affiliation(s)
| | - Saulius Bagdonas
- Laser Research Center
- Vilnius University
- LT-10222 Vilnius
- Lithuania
| | - Žilvinas Anusevičius
- Institute of Biochemistry
- Life Sciences Center
- Vilnius University
- LT-10257 Vilnius
- Lithuania
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12
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Baseer S, Ahmad S, Ranaghan KE, Azam SS. Towards a peptide-based vaccine against Shigella sonnei : A subtractive reverse vaccinology based approach. Biologicals 2017; 50:87-99. [DOI: 10.1016/j.biologicals.2017.08.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 07/11/2017] [Accepted: 08/08/2017] [Indexed: 02/06/2023] Open
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13
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Morales EH, Pinto CA, Luraschi R, Muñoz-Villagrán CM, Cornejo FA, Simpkins SW, Nelson J, Arenas FA, Piotrowski JS, Myers CL, Mori H, Vásquez CC. Accumulation of heme biosynthetic intermediates contributes to the antibacterial action of the metalloid tellurite. Nat Commun 2017; 8:15320. [PMID: 28492282 PMCID: PMC5437285 DOI: 10.1038/ncomms15320] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 03/21/2017] [Indexed: 01/08/2023] Open
Abstract
The metalloid tellurite is highly toxic to microorganisms. Several mechanisms of action have been proposed, including thiol depletion and generation of hydrogen peroxide and superoxide, but none of them can fully explain its toxicity. Here we use a combination of directed evolution and chemical and biochemical approaches to demonstrate that tellurite inhibits heme biosynthesis, leading to the accumulation of intermediates of this pathway and hydroxyl radical. Unexpectedly, the development of tellurite resistance is accompanied by increased susceptibility to hydrogen peroxide. Furthermore, we show that the heme precursor 5-aminolevulinic acid, which is used as an antimicrobial agent in photodynamic therapy, potentiates tellurite toxicity. Our results define a mechanism of tellurite toxicity and warrant further research on the potential use of the combination of tellurite and 5-aminolevulinic acid in antimicrobial therapy. The mechanisms of action of the antibacterial metalloid tellurite are unclear. Here, the authors show that tellurite induces an accumulation of hydroxyl radical and intermediates of heme biosynthesis in E. coli, and that the heme precursor 5-aminolevulinic acid potentiates tellurite toxicity.
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Affiliation(s)
- Eduardo H Morales
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | - Camilo A Pinto
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | - Roberto Luraschi
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | | | - Fabián A Cornejo
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | - Scott W Simpkins
- University of Minnesota-Twin Cities, Bioinformatics and Computational Biology, Minneapolis, Minnesota 55455, USA
| | - Justin Nelson
- University of Minnesota-Twin Cities, Bioinformatics and Computational Biology, Minneapolis, Minnesota 55455, USA
| | - Felipe A Arenas
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | | | - Chad L Myers
- University of Minnesota-Twin Cities, Bioinformatics and Computational Biology, Minneapolis, Minnesota 55455, USA.,University of Minnesota-Twin Cities, Department of Computer Science and Engineering, Minneapolis, Minnesota 55455, USA
| | - Hirotada Mori
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Claudio C Vásquez
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile
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14
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Giner-Lamia J, Pereira SB, Bovea-Marco M, Futschik ME, Tamagnini P, Oliveira P. Extracellular Proteins: Novel Key Components of Metal Resistance in Cyanobacteria? Front Microbiol 2016; 7:878. [PMID: 27375598 PMCID: PMC4894872 DOI: 10.3389/fmicb.2016.00878] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/24/2016] [Indexed: 11/13/2022] Open
Abstract
Metals are essential for all living organisms and required for fundamental biochemical processes. However, when in excess, metals can turn into highly-toxic agents able to disrupt cell membranes, alter enzymatic activities, and damage DNA. Metal concentrations are therefore tightly controlled inside cells, particularly in cyanobacteria. Cyanobacteria are ecologically relevant prokaryotes that perform oxygenic photosynthesis and can be found in many different marine and freshwater ecosystems, including environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been widely studied in cyanobacteria. So far, most studies have focused on how cells are capable of controlling their internal metal pools, with a strong bias toward the analysis of intracellular processes. Ultrastructure, modulation of physiology, dynamic changes in transcription and protein levels have been studied, but what takes place in the extracellular environment when cells are exposed to an unbalanced metal availability remains largely unknown. The interest in studying the subset of proteins present in the extracellular space has only recently begun and the identification and functional analysis of the cyanobacterial exoproteomes are just emerging. Remarkably, metal-related proteins such as the copper-chaperone CopM or the iron-binding protein FutA2 have already been identified outside the cell. With this perspective, we aim to raise the awareness that metal-resistance mechanisms are not yet fully known and hope to motivate future studies assessing the role of extracellular proteins on bacterial metal homeostasis, with a special focus on cyanobacteria.
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Affiliation(s)
- Joaquín Giner-Lamia
- Systems Biology and Bioinformatics Laboratory, Centro de Ciências do Mar, Universidade do AlgarveFaro, Portugal; Center for Biomedical Research, Universidade do AlgarveFaro, Portugal
| | - Sara B Pereira
- Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal
| | | | - Matthias E Futschik
- Systems Biology and Bioinformatics Laboratory, Centro de Ciências do Mar, Universidade do AlgarveFaro, Portugal; Center for Biomedical Research, Universidade do AlgarveFaro, Portugal
| | - Paula Tamagnini
- Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal; Faculdade de Ciências, Departamento de Biologia, Universidade do PortoPorto, Portugal
| | - Paulo Oliveira
- Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal
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15
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Sachla AJ, Eichenbaum Z. The GAS PefCD exporter is a MDR system that confers resistance to heme and structurally diverse compounds. BMC Microbiol 2016; 16:68. [PMID: 27095127 PMCID: PMC4837585 DOI: 10.1186/s12866-016-0687-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Accepted: 04/13/2016] [Indexed: 11/13/2022] Open
Abstract
Background Group A streptococcus (GAS) is the etiological agent of a variety of local and invasive infections as well as post-infection complications in humans. This β-hemolytic bacterium encounters environmental heme in vivo in a concentration that depends on the infection type and stage. While heme is a noxious molecule, the regulation of cellular heme levels and toxicity is underappreciated in GAS. We previously reported that heme induces three GAS genes that are similar to the pefRCD (porphyrin regulated efflux) genes from group B streptococcus. Here, we investigate the contributions of the GAS pef genes to heme management and physiology. Results In silico analysis revealed that the PefCD proteins entail a Class-1 ABC-type transporter with homology to selected MDR systems from Gram-positive bacteria. RT-PCR experiments confirmed that the pefRCD genes are transcribed to polycistronic mRNA and that a pefC insertion inactivation mutant lost the expression of both pefC and pefD genes. This mutant was hypersensitive to heme, exhibiting significant growth inhibition already in the presence of 1 μM heme. In addition, the pefC mutant was more sensitive to several drugs and nucleic acid dyes and demonstrated higher cellular accumulation of heme in comparison with the wild type and the complemented strains. Finally, the absence of the PefCD transporter potentiated the damaging effects of heme on GAS building blocks including lipids and DNA. Conclusion We show here that in GAS, the pefCD genes encode a multi-drug efflux system that allows the bacterium to circumvent the challenges imposed by labile heme. This is the first heme resistance machinery described in GAS.
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Affiliation(s)
- Ankita J Sachla
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Zehava Eichenbaum
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.
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16
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Schmidt RM, Carter MM, Chu ML, Latario CJ, Stadler SK, Stauff DL. Heme sensing in Bacillus thuringiensis: a supplementary HssRS-regulated heme resistance system. FEMS Microbiol Lett 2016; 363:fnw076. [PMID: 27030728 DOI: 10.1093/femsle/fnw076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2016] [Indexed: 12/16/2022] Open
Abstract
Several Gram-positive pathogens scavenge host-derived heme to satisfy their nutritional iron requirement. However, heme is a toxic molecule capable of damaging the bacterial cell. Gram-positive pathogens within the phylum Firmicutes overcome heme toxicity by sensing heme through HssRS, a two-component system that regulates the heme detoxification transporter HrtAB. Here we show that heme sensing by HssRS and heme detoxification by HrtAB occur in the insect pathogen Bacillus thuringiensis We find that in B. thuringiensis, HssRS directly regulates an operon, hrmXY, encoding hypothetical membrane proteins that are not found in other Firmicutes with characterized HssRS and HrtAB systems. This novel HssRS-regulated operon or its orthologs BMB171_c3178 and BMB171_c3330 are required for maximal heme resistance. Furthermore, the activity of HrmXY is not dependent on expression of HrtAB. These results suggest that B. thuringiensis senses heme through HssRS and induces expression of separate membrane-localized systems capable of overcoming different aspects of heme toxicity.
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Affiliation(s)
- Rachel M Schmidt
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
| | - Micaela M Carter
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
| | - Michelle L Chu
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
| | - Casey J Latario
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
| | - Sarah K Stadler
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
| | - Devin L Stauff
- Department of Biology, Grove City College, 100 Campus Drive, Grove City, PA 16127, USA
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17
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Zhang C, Chen X, Stephanopoulos G, Too HP. Efflux transporter engineering markedly improves amorphadiene production inEscherichia coli. Biotechnol Bioeng 2016; 113:1755-63. [DOI: 10.1002/bit.25943] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/21/2015] [Accepted: 01/18/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Congqiang Zhang
- Chemical and Pharmaceutical Engineering; Singapore-MIT Alliance; 4 Engineering Drive 3 Singapore Singapore
- Biotransformation Innovation Platform (BioTrans); Agency for Science, Technology and Research (A*STAR); Singapore Singapore
| | - Xixian Chen
- Chemical and Pharmaceutical Engineering; Singapore-MIT Alliance; 4 Engineering Drive 3 Singapore Singapore
- Biotransformation Innovation Platform (BioTrans); Agency for Science, Technology and Research (A*STAR); Singapore Singapore
| | - Gregory Stephanopoulos
- Chemical and Pharmaceutical Engineering; Singapore-MIT Alliance; 4 Engineering Drive 3 Singapore Singapore
- Department of Chemical Engineering; Massachusetts Institute of Technology; Cambridge Massachusetts
| | - Heng-Phon Too
- Chemical and Pharmaceutical Engineering; Singapore-MIT Alliance; 4 Engineering Drive 3 Singapore Singapore
- Biotransformation Innovation Platform (BioTrans); Agency for Science, Technology and Research (A*STAR); Singapore Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine; National University of Singapore, 8 Medical Drive; Blk MD7, Level 4 Singapore 117597 Singapore
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18
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Quehl P, Hollender J, Schüürmann J, Brossette T, Maas R, Jose J. Co-expression of active human cytochrome P450 1A2 and cytochrome P450 reductase on the cell surface of Escherichia coli. Microb Cell Fact 2016; 15:26. [PMID: 26838175 PMCID: PMC4736170 DOI: 10.1186/s12934-016-0427-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/19/2016] [Indexed: 11/23/2022] Open
Abstract
Background Human cytochrome P450 (CYP) enzymes mediate the first step in the breakdown of most drugs and are strongly involved in drug–drug interactions, drug clearance and activation of prodrugs. Their biocatalytic behavior is a key parameter during drug development which requires preparative synthesis of CYP related drug metabolites. However, recombinant expression of CYP enzymes is a challenging bottleneck for drug metabolite biosynthesis. Therefore, we developed a novel approach by displaying human cytochrome P450 1A2 (CYP1A2) and cytochrome P450 reductase (CPR) on the surface of Escherichia coli. Results To present human CYP1A2 and CPR on the surface, we employed autodisplay. Both enzymes were displayed on the surface which was demonstrated by protease and antibody accessibility tests. CPR activity was first confirmed with the protein substrate cytochrome c. Cells co-expressing CYP1A2 and CPR were capable of catalyzing the conversion of the known CYP1A2 substrates 7-ethoxyresorufin, phenacetin and the artificial substrate luciferin-MultiCYP, which would not have been possible without interaction of both enzymes. Biocatalytic activity was strongly influenced by the composition of the growth medium. Addition of 5-aminolevulinic acid was necessary to obtain a fully active whole cell biocatalyst and was superior to the addition of heme. Conclusion We demonstrated that CYP1A2 and CPR can be co-expressed catalytically active on the cell surface of E. coli. It is a promising step towards pharmaceutical applications such as the synthesis of drug metabolites. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0427-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paul Quehl
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
| | - Joel Hollender
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany. .,Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Jan Schüürmann
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
| | - Tatjana Brossette
- Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Ruth Maas
- Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Joachim Jose
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
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19
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Halpern D, Gruss A. A sensitive bacterial-growth-based test reveals how intestinal Bacteroides meet their porphyrin requirement. BMC Microbiol 2015; 15:282. [PMID: 26715069 PMCID: PMC4696147 DOI: 10.1186/s12866-015-0616-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 12/16/2015] [Indexed: 12/19/2022] Open
Abstract
Background Bacteroides sp. are dominant constituents of the human and animal intestinal microbiota require porphyrins (i.e., protoporphyrin IX or iron-charged heme) for normal growth. The highly stimulatory effect of porphyrins on Bacteroides growth lead us to propose their use as a potential determinant of bacterial colonization. However, showing a role for porphryins would require sensitive detection methods that work in complex samples such as feces. Results We devised a highly sensitive semi-quantitative porphyrin detection method (detection limit 1-4 ng heme or PPIX) that can be used to assay pure or complex biological samples, based on Bacteroides growth stimulation. The test revealed that healthy colonized or non-colonized murine and human hosts provide porphyrins in feces, which stimulate Bacteroides growth. In addition, a common microbiota constituent, Escherichia coli, is shown to be a porphyrin donor, suggesting a novel basis for intestinal bacterial interactions. Conclusions A highly sensitive method to detect porphyrins based on bacterial growth is devised and is functional in complex biological samples. Host feces, independently of their microbiota, and E. coli, which are present in the intestine, are shown to be porphryin donors. The role of porphyrins as key bioactive molecules can now be assessed for their impact on Bacteroides and other bacterial populations in the gut. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0616-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- David Halpern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France, Jouy en Josas, 78352, France.
| | - Alexandra Gruss
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France, Jouy en Josas, 78352, France.
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20
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Piedrafita G, Keller MA, Ralser M. The Impact of Non-Enzymatic Reactions and Enzyme Promiscuity on Cellular Metabolism during (Oxidative) Stress Conditions. Biomolecules 2015; 5:2101-22. [PMID: 26378592 PMCID: PMC4598790 DOI: 10.3390/biom5032101] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 08/03/2015] [Accepted: 08/31/2015] [Indexed: 11/16/2022] Open
Abstract
Cellular metabolism assembles in a structurally highly conserved, but functionally dynamic system, known as the metabolic network. This network involves highly active, enzyme-catalyzed metabolic pathways that provide the building blocks for cell growth. In parallel, however, chemical reactivity of metabolites and unspecific enzyme function give rise to a number of side products that are not part of canonical metabolic pathways. It is increasingly acknowledged that these molecules are important for the evolution of metabolism, affect metabolic efficiency, and that they play a potential role in human disease—age-related disorders and cancer in particular. In this review we discuss the impact of oxidative and other cellular stressors on the formation of metabolic side products, which originate as a consequence of: (i) chemical reactivity or modification of regular metabolites; (ii) through modifications in substrate specificity of damaged enzymes; and (iii) through altered metabolic flux that protects cells in stress conditions. In particular, oxidative and heat stress conditions are causative of metabolite and enzymatic damage and thus promote the non-canonical metabolic activity of the cells through an increased repertoire of side products. On the basis of selected examples, we discuss the consequences of non-canonical metabolic reactivity on evolution, function and repair of the metabolic network.
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Affiliation(s)
- Gabriel Piedrafita
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK.
| | - Markus A Keller
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK.
| | - Markus Ralser
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK.
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW1 7AA, UK.
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21
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Turlin E, Heuck G, Simões Brandão MI, Szili N, Mellin JR, Lange N, Wandersman C. Protoporphyrin (PPIX) efflux by the MacAB-TolC pump in Escherichia coli. Microbiologyopen 2014; 3:849-59. [PMID: 25257218 PMCID: PMC4263509 DOI: 10.1002/mbo3.203] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/01/2014] [Accepted: 07/08/2014] [Indexed: 12/24/2022] Open
Abstract
In most organisms, heme biosynthesis is strictly controlled so as to avoid heme and heme precursor accumulation, which is toxic. Escherichia coli regulates heme biosynthesis by a feedback loop involving heme-induced proteolytic cleavage of HemA, glutamyl-tRNA reductase, which is the first enzyme in the heme biosynthetic pathway. We show here that heme homeostasis can be disrupted by overproduction of YfeX, a cytoplasmic protein that captures iron from heme that we named deferrochelatase. We also show that it is disrupted by iron chelation, which reduces the intracellular iron concentration necessary for loading iron into protoporphyrin IX (PPIX, the immediate heme precursor). In both cases, we established that there is an increased PPIX concentration and we demonstrate that this compound is expelled by the MacAB-TolC pump, an efflux pump involved in E. coli and Salmonella for macrolide efflux. The E. coli macAB and tolC mutants accumulate PPIX and are sensitive to photo-inactivation. The MacAB-TolC pump is required for Salmonella typhimurium survival in macrophages. We propose that PPIX is an endogenous substrate of the MacAB-TolC pump in E. coli and S. typhimurium and that this compound is produced inside bacteria when natural heme homeostasis is disrupted by iron shortage, as happens when bacteria invade the mammalian host.
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Affiliation(s)
- Evelyne Turlin
- Unité des Membranes Bactériennes, Département de Microbiologie, Institut Pasteur, 75724, Paris Cedex 15, France
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22
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TolC promotes ExPEC biofilm formation and curli production in response to medium osmolarity. BIOMED RESEARCH INTERNATIONAL 2014; 2014:574274. [PMID: 25243151 PMCID: PMC4163439 DOI: 10.1155/2014/574274] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 08/05/2014] [Indexed: 11/17/2022]
Abstract
While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2 M9 medium. We propose for the first time that TolC protein is able to form biofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation.
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23
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Schüürmann J, Quehl P, Festel G, Jose J. Bacterial whole-cell biocatalysts by surface display of enzymes: toward industrial application. Appl Microbiol Biotechnol 2014; 98:8031-46. [DOI: 10.1007/s00253-014-5897-y] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 11/24/2022]
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24
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Efficient Biotransformations UsingEscherichia coliwithtolCacrABMutations Expressing Cytochrome P450 Genes. Biosci Biotechnol Biochem 2014; 73:805-10. [DOI: 10.1271/bbb.80627] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Vega DE, Young KD. Accumulation of periplasmic enterobactin impairs the growth and morphology of Escherichia coli tolC mutants. Mol Microbiol 2013; 91:508-21. [PMID: 24330203 DOI: 10.1111/mmi.12473] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2013] [Indexed: 01/01/2023]
Abstract
TolC is the outer membrane component of tripartite efflux pumps, which expel proteins, toxins and antimicrobial agents from Gram-negative bacteria. Escherichia coli tolC mutants grow well and are slightly elongated in rich media but grow less well than wild-type cells in minimal media. These phenotypes have no physiological explanation as yet. Here, we find that tolC mutants have highly aberrant shapes when grown in M9-glucose medium but that adding iron restores wild-type morphology. When starved for iron, E. coli tolC mutants synthesize but cannot secrete the siderophore enterobactin, which collects in the periplasm. tolC mutants unable to synthesize enterobactin display no growth or morphological defects, and adding exogenous enterobactin recreates these aberrations, implicating this compound as the causative agent. Cells unable to import enterobactin across the outer membrane grow normally, whereas cells that import enterobactin only to the periplasm become morphologically aberrant. Thus, tolC mutants grown in low iron conditions accumulate periplasmic enterobactin, which impairs bacterial morphology, possibly by sequestering iron and inhibiting an iron-dependent reaction involved in cell division or peptidoglycan synthesis. The results also highlight the need to supply sufficient iron when studying TolC-directed export or efflux, to eliminate extraneous physiological effects.
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Affiliation(s)
- Daniel E Vega
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205-7199, USA
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26
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Kourtesi C, Ball AR, Huang YY, Jachak SM, Vera DMA, Khondkar P, Gibbons S, Hamblin MR, Tegos GP. Microbial efflux systems and inhibitors: approaches to drug discovery and the challenge of clinical implementation. Open Microbiol J 2013; 7:34-52. [PMID: 23569468 PMCID: PMC3617545 DOI: 10.2174/1874285801307010034] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/22/2013] [Accepted: 01/23/2013] [Indexed: 12/16/2022] Open
Abstract
Conventional antimicrobials are increasingly ineffective due to the emergence of multidrug-resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered exploration for novel and unconventional approaches to controlling microbial infections. Multidrug efflux systems (MES) have been a profound obstacle in the successful deployment of antimicrobials. The discovery of small molecule efflux system blockers has been an active and rapidly expanding research discipline. A major theme in this platform involves efflux pump inhibitors (EPIs) from natural sources. The discovery methodologies and the available number of natural EPI-chemotypes are increasing. Advances in our understanding of microbial physiology have shed light on a series of pathways and phenotypes where the role of efflux systems is pivotal. Complementing existing antimicrobial discovery platforms such as photodynamic therapy (PDT) with efflux inhibition is a subject under investigation. This core information is a stepping stone in the challenge of highlighting an effective drug development path for EPIs since the puzzle of clinical implementation remains unsolved. This review summarizes advances in the path of EPI discovery, discusses potential avenues of EPI implementation and development, and underlines the need for highly informative and comprehensive translational approaches.
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Affiliation(s)
- Christina Kourtesi
- Department of Pathology, University of New Mexico, School of Medicine, Albuquerque, NM, USA ; Department of Pathology, Faculty of Medicine, National & Kapodistrian University of Athens, Greece
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27
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Reduction of cellular stress by TolC-dependent efflux pumps in Escherichia coli indicated by BaeSR and CpxARP activation of spy in efflux mutants. J Bacteriol 2012; 195:1042-50. [PMID: 23264577 DOI: 10.1128/jb.01996-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli has nine inner membrane efflux pumps which complex with the outer membrane protein TolC and cognate membrane fusion proteins to form tripartite transperiplasmic pumps with diverse functions, including the expulsion of antibiotics. We recently observed that tolC mutants have elevated activities for three stress response regulators, MarA, SoxS, and Rob, and we suggested that TolC-dependent efflux is required to prevent the accumulation of stressful cellular metabolites. Here, we used spy::lacZ fusions to show that two systems for sensing/repairing extracytoplasmic stress, BaeRS and CpxARP, are activated in the absence of TolC-dependent efflux. In either tolC mutants or bacteria with mutations in the genes for four TolC-dependent efflux pumps, spy expression was increased 6- to 8-fold. spy encodes a periplasmic chaperone regulated by the BaeRS and CpxARP stress response systems. The overexpression of spy in tolC or multiple efflux pump mutants also depended on these systems. spy overexpression was not due to acetate, ethanol, or indole accumulation, since external acetate had only a minor effect on wild-type cells, ethanol had a large effect that was not CpxA dependent, and a tolC tnaA mutant which cannot accumulate internal indole overexpressed spy. We propose that, unless TolC-dependent pumps excrete certain metabolites, the metabolites accumulate and activate at least five different stress response systems.
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Schumacher SD, Jose J. Expression of active human P450 3A4 on the cell surface of Escherichia coli by Autodisplay. J Biotechnol 2012; 161:113-20. [DOI: 10.1016/j.jbiotec.2012.01.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/17/2012] [Accepted: 01/26/2012] [Indexed: 10/14/2022]
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29
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Jose J, Maas RM, Teese MG. Autodisplay of enzymes—Molecular basis and perspectives. J Biotechnol 2012; 161:92-103. [DOI: 10.1016/j.jbiotec.2012.04.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 02/14/2012] [Accepted: 04/04/2012] [Indexed: 11/16/2022]
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The bhuQ gene encodes a heme oxygenase that contributes to the ability of Brucella abortus 2308 to use heme as an iron source and is regulated by Irr. J Bacteriol 2012; 194:4052-8. [PMID: 22636783 DOI: 10.1128/jb.00367-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Brucella BhuQ protein is a homolog of the Bradyrhizobium japonicum heme oxygenases HmuD and HmuQ. To determine if this protein plays a role in the ability of Brucella abortus 2308 to use heme as an iron source, an isogenic bhuQ mutant was constructed and its phenotype evaluated. Although the Brucella abortus bhuQ mutant DCO1 did not exhibit a defect in its capacity to use heme as an iron source or evidence of increased heme toxicity in vitro, this mutant produced increased levels of siderophore in response to iron deprivation compared to 2308. Introduction of a bhuQ mutation into the B. abortus dhbC mutant BHB2 (which cannot produce siderophores) resulted in a severe growth defect in the dhbC bhuQ double mutant JFO1 during cultivation under iron-restricted conditions, which could be rescued by the addition of FeCl(3), but not heme, to the growth medium. The bhuQ gene is cotranscribed with the gene encoding the iron-responsive regulator RirA, and both of these genes are repressed by the other major iron-responsive regulator in the alphaproteobacteria, Irr. The results of these studies suggest that B. abortus 2308 has at least one other heme oxygenase that works in concert with BhuQ to allow this strain to efficiently use heme as an iron source. The genetic organization of the rirA-bhuQ operon also provides the basis for the proposition that BhuQ may perform a previously unrecognized function by allowing the transcriptional regulator RirA to recognize heme as an iron source.
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Schumacher SD, Hannemann F, Teese MG, Bernhardt R, Jose J. Autodisplay of functional CYP106A2 in Escherichia coli. J Biotechnol 2012; 161:104-12. [PMID: 22426093 DOI: 10.1016/j.jbiotec.2012.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/07/2012] [Accepted: 02/29/2012] [Indexed: 01/02/2023]
Abstract
Cytochrome P450 enzymes catalyse a wide variety of reactions, including the hydroxylation and epoxidation of CC bonds, and dealkylation reactions. There is high interest in these reactions for biotechnology and pharmaceutical processes. Many P450s require membrane surroundings and have substrates that do not cross biological membranes. To circumvent these obstacles, CYP106A2 from Bacillus megaterium was expressed on the outer membrane of Escherichia coli cells by Autodisplay. Exposure on the surface was confirmed by a protease accessibility test and flow cytometry after immunolabelling. HPLC assays showed that 0.5 ml of cells displaying the enzyme (OD₅₇₈ = 6) converted 9.13 μmol of deoxycorticosterone to 15β-OH-deoxycorticosterone within 1h. Imipramine and abietic acid were also accepted as substrates. The number of active enzyme molecules per cell was calculated to be 20,000. Surprisingly, surface-exposed CYP106A2 was active in E. coli BL21 without the external addition of the heme group. However, when CYP106A2 was expressed on the surface of an E. coli strain lacking the TolC channel protein (JW5503), enzymatic activity was almost completely abolished. The activity of CYP106A2 on the surface of E. coli JW5503 could be restored by the external addition of the heme group. This suggests, as has been reported before, that E. coli uses a TolC-dependent mechanism to export heme into the growth media, where it can be scavenged by a surface-displayed apoenzyme. Our results indicate that Autodisplay enables the functional surface display of P450 enzymes and provides a new platform to access their synthetic potential.
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Affiliation(s)
- Stephanie D Schumacher
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
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Vera DMA, Haynes MH, Ball AR, Dai T, Astrakas C, Kelso MJ, Hamblin MR, Tegos GP. Strategies to potentiate antimicrobial photoinactivation by overcoming resistant phenotypes. Photochem Photobiol 2012; 88:499-511. [PMID: 22242675 DOI: 10.1111/j.1751-1097.2012.01087.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Conventional antimicrobial strategies have become increasingly ineffective due to the emergence of multidrug resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered the exploration of alternative treatments and unconventional approaches towards controlling microbial infections. Photodynamic therapy (PDT) was originally established as an anticancer modality and is currently used in the treatment of age-related macular degeneration. The concept of photodynamic inactivation requires cell exposure to light energy, typically wavelengths in the visible region that causes the excitation of photosensitizer molecules either exogenous or endogenous, which results in the production of reactive oxygen species (ROS). ROS produce cell inactivation and death through modification of intracellular components. The versatile characteristics of PDT prompted its investigation as an anti-infective discovery platform. Advances in understanding of microbial physiology have shed light on a series of pathways, and phenotypes that serve as putative targets for antimicrobial drug discovery. Investigations of these phenotypic elements in concert with PDT have been reported focused on multidrug efflux systems, biofilms, virulence and pathogenesis determinants. In many instances the results are promising but only preliminary and require further investigation. This review discusses the different antimicrobial PDT strategies and highlights the need for highly informative and comprehensive discovery approaches.
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Affiliation(s)
- Domingo Mariano Adolfo Vera
- Department of Chemistry, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
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Yow CMN, Tang HM, Chu ESM, Huang Z. Hypericin-mediated photodynamic antimicrobial effect on clinically isolated pathogens. Photochem Photobiol 2012; 88:626-32. [PMID: 22233203 DOI: 10.1111/j.1751-1097.2012.01085.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The aim of this study was to determine the photodynamic antimicrobial effect of hypericin on clinically isolated Staphylococcus aureus and Escherichia coli cells. Bacterial cells (10(8) cells per mL) were incubated with hypericin (0-40 μM) for 30 min and followed by light irradiation of 600-800 nm at 5-30 J cm(-2). Cell survival was determined by colony counting, cellular hypericin uptake examined by flow cytometer, and cell membrane damage examined by scanning electron microscopy and leakage assay. The effectiveness of hypericin-mediated photodynamic killing was strongly affected by cellular structure and photosensitizer uptake. The combination of hypericin and light irradiation could induce significant killing of Gram positive methicillin-sensitive and -resistant S. aureus cells (>6 log reduction), but was not effective on Gram negative E. coli cells (<0.2 log reduction). The difference was caused by different cell wall/membrane structures that directly affected cellular uptake of hypericin.
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Affiliation(s)
- Christine M N Yow
- Section of Medical Laboratory Science, Department of Health Technology & Informatics, Hong Kong Polytechnic University, Kowlong, HKSAR, China.
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St Denis TG, Dai T, Izikson L, Astrakas C, Anderson RR, Hamblin MR, Tegos GP. All you need is light: antimicrobial photoinactivation as an evolving and emerging discovery strategy against infectious disease. Virulence 2011; 2:509-20. [PMID: 21971183 DOI: 10.4161/viru.2.6.17889] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The story of prevention and control of infectious diseases remains open and a series of highly virulent pathogens are emerging both in and beyond the hospital setting. Antibiotics were an absolute success story for a previous era. The academic and industrial biomedical communities have now come together to formulate consensus beliefs regarding the pursuit of novel and effective alternative anti-infective countermeasures. Photodynamic therapy was established and remains a successful modality for malignancies but photodynamic inactivation has been transformed recently to an antimicrobial discovery and development platform. The concept of photodynamic inactivation is quite straightforward and requires microbial exposure to visible light energy, typically wavelengths in the visible region, that causes the excitation of photosensitizer molecules (either exogenous or endogenous), which results in the production of singlet oxygen and other reactive oxygen species that react with intracellular components, and consequently produce cell inactivation. It is an area of increasing interest, as research is advancing i) to identify the photochemical and photophysical mechanisms involved in inactivation; ii) to develop potent and clinically compatible photosensitizer; iii) to understand how photoinactivation is affected by key microbial phenotypic elements (multidrug resistance and efflux, virulence and pathogenesis determinants, biofilms); iv) to explore novel delivery platforms inspired by current trends in pharmacology and nanotechnology; and v) to identify photoinactivation applications beyond the clinical setting such as environmental disinfectants.
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Affiliation(s)
- Tyler G St Denis
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
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Zgurskaya HI, Krishnamoorthy G, Ntreh A, Lu S. Mechanism and Function of the Outer Membrane Channel TolC in Multidrug Resistance and Physiology of Enterobacteria. Front Microbiol 2011; 2:189. [PMID: 21954395 PMCID: PMC3174397 DOI: 10.3389/fmicb.2011.00189] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 08/25/2011] [Indexed: 01/18/2023] Open
Abstract
TolC is an archetypal member of the outer membrane efflux protein (OEP) family. These proteins are involved in export of small molecules and toxins across the outer membrane of Gram-negative bacteria. Genomes of some bacteria such as Pseudomonas species contain multiple copies of OEPs. In contrast, enterobacteria contain a single tolC gene, the product of which functions with multiple transporters. Inactivation of tolC has a major impact on enterobacterial physiology and virulence. Recent studies suggest that the role of TolC in physiology of enterobacteria is very broad and affects almost all aspects of cell adaptation to adverse environments. We review the current state of understanding TolC structure and present an integrated view of TolC function in enterobacteria. We propose that seemingly unrelated phenotypes of tolC mutants are linked together by a single most common condition – an oxidative damage to membranes.
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Affiliation(s)
- Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma Norman, OK, USA
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Deininger KNW, Horikawa A, Kitko RD, Tatsumi R, Rosner JL, Wachi M, Slonczewski JL. A requirement of TolC and MDR efflux pumps for acid adaptation and GadAB induction in Escherichia coli. PLoS One 2011; 6:e18960. [PMID: 21541325 PMCID: PMC3082540 DOI: 10.1371/journal.pone.0018960] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 03/14/2011] [Indexed: 12/04/2022] Open
Abstract
Background The TolC outer membrane channel is a key component of several multidrug resistance (MDR) efflux pumps driven by H+ transport in Escherichia coli. While tolC expression is under the regulation of the EvgA-Gad acid resistance regulon, the role of TolC in growth at low pH and extreme-acid survival is unknown. Methods and Principal Findings TolC was required for extreme-acid survival (pH 2) of strain W3110 grown aerobically to stationary phase. A tolC deletion decreased extreme-acid survival (acid resistance) of aerated pH 7.0-grown cells by 105-fold and of pH 5.5-grown cells by 10-fold. The requirement was specific for acid resistance since a tolC defect had no effect on aerobic survival in extreme base (pH 10). TolC was required for expression of glutamate decarboxylase (GadA, GadB), a key component of glutamate-dependent acid resistance (Gad). TolC was also required for maximal exponential growth of E. coli K-12 W3110, in LBK medium buffered at pH 4.5–6.0, but not at pH 6.5–8.5. The TolC growth requirement in moderate acid was independent of Gad. TolC-associated pump components EmrB and MdtB contributed to survival in extreme acid (pH 2), but were not required for growth at pH 5. A mutant lacking the known TolC-associated efflux pumps (acrB, acrD, emrB, emrY, macB, mdtC, mdtF, acrEF) showed no growth defect at acidic pH and a relatively small decrease in extreme-acid survival when pre-grown at pH 5.5. Conclusions TolC and proton-driven MDR efflux pump components EmrB and MdtB contribute to E. coli survival in extreme acid and TolC is required for maximal growth rates below pH 6.5. The TolC enhancement of extreme-acid survival includes Gad induction, but TolC-dependent growth rates below pH 6.5 do not involve Gad. That MDR resistance can enhance growth and survival in acid is an important consideration for enteric organisms passing through the acidic stomach.
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Affiliation(s)
| | - Akina Horikawa
- Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Ryan D. Kitko
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
| | - Ryoko Tatsumi
- Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Judah L. Rosner
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Masaaki Wachi
- Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Joan L. Slonczewski
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
- * E-mail:
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Stauff DL, Skaar EP. Bacillus anthracis HssRS signalling to HrtAB regulates haem resistance during infection. Mol Microbiol 2010; 72:763-78. [PMID: 19400785 DOI: 10.1111/j.1365-2958.2009.06684.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bacillus anthracis proliferates to high levels within vertebrate tissues during the pathogenesis of anthrax. This growth is facilitated by the acquisition of nutrient iron from host haem. However, haem acquisition can lead to the accumulation of toxic amounts of haem within B. anthracis. Here, we show that B. anthracis resists haem toxicity by sensing haem through the HssRS two-component system, which regulates expression of the haem-detoxifying transporter HrtAB. In addition, we demonstrate that B. anthracis exhibits elevated HssRS function compared with its evolutionary relative Staphylococcus aureus. Elevated haem sensing is likely required by B. anthracis due to the significant haem sensitivity exhibited by members of the genus Bacilli. We also demonstrate that B. anthracis depends on conserved residues within the previously uncharacterized sensing domain of the histidine kinase HssS for HssS function. Finally, we show that the haem- and HssRS-regulated hrtAB promoter is activated in a murine model of anthrax. These results demonstrate the evolutionary conservation of haem sensing among multiple Gram-positive bacteria and begin to provide a mechanistic explanation for the haem resistance of B. anthracis. Further, these data suggest that haem stress is experienced by bacterial pathogens during infection.
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Affiliation(s)
- Devin L Stauff
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Dhamdhere G, Zgurskaya HI. Metabolic shutdown in Escherichia coli cells lacking the outer membrane channel TolC. Mol Microbiol 2010; 77:743-54. [PMID: 20545840 DOI: 10.1111/j.1365-2958.2010.07245.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The outer membrane channel TolC is a key component of multidrug efflux and type I secretion transporters in Escherichia coli. Mutational inactivation of TolC renders cells highly susceptible to antibiotics and leads to defects in secretion of protein toxins. Despite impairment of various transport functions, no growth defects were reported in cells lacking TolC. Unexpectedly, we found that the loss of TolC notably impairs cell division and growth in minimal glucose medium. The TolC-dependent phenotype was further exacerbated by the loss of ygiB and ygiC genes expressed in the same operon as tolC and their homologues yjfM and yjfC located elsewhere on the chromosome. Our results show that this growth deficiency is caused by depletion of the critical metabolite NAD(+) and high NADH/NAD(+) ratios. The increased amounts of PspA and decreased rates of NADH oxidation in Delta tolC membranes indicated stress on the membrane and dissipation of a proton motive force. We conclude that inactivation of TolC triggers metabolic shutdown in E. coli cells grown in minimal glucose medium. The Delta tolC phenotype is partially rescued by YgiBC and YjfMC, which have parallel functions independent from TolC.
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Affiliation(s)
- Girija Dhamdhere
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Room 208, Norman, OK 73019, USA
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Fernandez A, Lechardeur D, Derré-Bobillot A, Couvé E, Gaudu P, Gruss A. Two coregulated efflux transporters modulate intracellular heme and protoporphyrin IX availability in Streptococcus agalactiae. PLoS Pathog 2010; 6:e1000860. [PMID: 20421944 PMCID: PMC2858704 DOI: 10.1371/journal.ppat.1000860] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 03/16/2010] [Indexed: 01/01/2023] Open
Abstract
Streptococcus agalactiae is a major neonatal pathogen whose infectious route involves septicemia. This pathogen does not synthesize heme, but scavenges it from blood to activate a respiration metabolism, which increases bacterial cell density and is required for full virulence. Factors that regulate heme pools in S. agalactiae are unknown. Here we report that one main strategy of heme and protoporphyrin IX (PPIX) homeostasis in S. agalactiae is based on a regulated system of efflux using two newly characterized operons, gbs1753 gbs1752 (called pefA pefB), and gbs1402 gbs1401 gbs1400 (called pefR pefC pefD), where pef stands for 'porphyrin-regulated efflux'. In vitro and in vivo data show that PefR, a MarR-superfamily protein, is a repressor of both operons. Heme or PPIX both alleviate PefR-mediated repression. We show that bacteria inactivated for both Pef efflux systems display accrued sensitivity to these porphyrins, and give evidence that they accumulate intracellularly. The DeltapefR mutant, in which both pef operons are up-regulated, is defective for heme-dependent respiration, and attenuated for virulence. We conclude that this new efflux regulon controls intracellular heme and PPIX availability in S. agalactiae, and is needed for its capacity to undergo respiration metabolism, and to infect the host.
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Affiliation(s)
- Annabelle Fernandez
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
- * E-mail: (AF); (AG)
| | - Delphine Lechardeur
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Aurélie Derré-Bobillot
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Elisabeth Couvé
- Institut Pasteur, Laboratoire Evolution et Génomique Bactérienne, CNRS URA 2171, Paris, France
| | - Philippe Gaudu
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Alexandra Gruss
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
- * E-mail: (AF); (AG)
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Abstract
Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario K1A OK9, Canada
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA
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Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact. Proc Natl Acad Sci U S A 2009; 106:11719-24. [PMID: 19564607 DOI: 10.1073/pnas.0903842106] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Because heme is a major iron-containing molecule in vertebrates, the ability to use heme-bound iron is a determining factor in successful infection by bacterial pathogens. Until today, all known enzymes performing iron extraction from heme did so through the rupture of the tetrapyrrol skeleton. Here, we identified 2 Escherichia coli paralogs, YfeX and EfeB, without any previously known physiological functions. YfeX and EfeB promote iron extraction from heme preserving the tetrapyrrol ring intact. This novel enzymatic reaction corresponds to the deferrochelation of the heme. YfeX and EfeB are the sole proteins able to provide iron from exogenous heme sources to E. coli. YfeX is located in the cytoplasm. EfeB is periplasmic and enables iron extraction from heme in the periplasm and iron uptake in the absence of any heme permease. YfeX and EfeB are widespread and highly conserved in bacteria. We propose that their physiological function is to retrieve iron from heme.
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Zgurskaya HI, Yamada Y, Tikhonova EB, Ge Q, Krishnamoorthy G. Structural and functional diversity of bacterial membrane fusion proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:794-807. [PMID: 19041958 DOI: 10.1016/j.bbapap.2008.10.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 10/21/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
Membrane Fusion Proteins (MFPs) are functional subunits of multi-component transporters that perform diverse physiological functions in both Gram-positive and Gram-negative bacteria. MFPs associate with transporters belonging to Resistance-Nodulation-cell Division (RND), ATP-Binding Cassette (ABC) and Major Facilitator (MF) superfamilies of proteins. Recent studies suggested that MFPs interact with substrates and play an active role in transport reactions. In addition, the MFP-dependent transporters from Gram-negative bacteria recruit the outer membrane channels to expel various substrates across the outer membrane into external medium. This review is focused on the diversity, structure and molecular mechanism of MFPs that function in multidrug efflux. Using phylogenetic approaches we analyzed diversity and representation of multidrug MFPs in sequenced bacterial genomes. In addition to previously characterized MFPs from Gram-negative bacteria, we identified MFPs that associate with RND-, MF- and ABC-type transporters in Gram-positive bacteria. Sequence analyses showed that MFPs vary significantly in size (200-650 amino acid residues) with some of them lacking the signature alpha-helical domain of multidrug MFPs. Furthermore, many transport operons contain two- or three genes encoding distinct MFPs. We further discuss the diversity of MFPs in the context of current views on the mechanism and structure of MFP-dependent transporters.
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Affiliation(s)
- Helen I Zgurskaya
- University of Oklahoma Department of Chemistry and Biochemistry 620 Parrington Oval, Room 208 Norman, OK 73019, USA.
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