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Duffey M, Jumde RP, da Costa RM, Ropponen HK, Blasco B, Piddock LJ. Extending the Potency and Lifespan of Antibiotics: Inhibitors of Gram-Negative Bacterial Efflux Pumps. ACS Infect Dis 2024; 10:1458-1482. [PMID: 38661541 PMCID: PMC11091901 DOI: 10.1021/acsinfecdis.4c00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/14/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024]
Abstract
Efflux is a natural process found in all prokaryotic and eukaryotic cells that removes a diverse range of substrates from inside to outside. Many antibiotics are substrates of bacterial efflux pumps, and modifications to the structure or overexpression of efflux pumps are an important resistance mechanism utilized by many multidrug-resistant bacteria. Therefore, chemical inhibition of bacterial efflux to revitalize existing antibiotics has been considered a promising approach for antimicrobial chemotherapy over two decades, and various strategies have been employed. In this review, we provide an overview of bacterial multidrug resistance (MDR) efflux pumps, of which the resistance nodulation division (RND) efflux pumps are considered the most clinically relevant in Gram-negative bacteria, and describe over 50 efflux inhibitors that target such systems. Although numerous efflux inhibitors have been identified to date, none have progressed into clinical use because of formulation, toxicity, and pharmacokinetic issues or a narrow spectrum of inhibition. For these reasons, the development of efflux inhibitors has been considered a difficult and complex area of research, and few active preclinical studies on efflux inhibitors are in progress. However, recently developed tools, including but not limited to computational tools including molecular docking models, offer hope that further research on efflux inhibitors can be a platform for research and development of new bacterial efflux inhibitors.
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Affiliation(s)
- Maëlle Duffey
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Ravindra P. Jumde
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Renata M.A. da Costa
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Henni-Karoliina Ropponen
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Benjamin Blasco
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Laura J.V. Piddock
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
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Baquero F, Rodríguez-Beltrán J, Coque TM, del Campo R. Boosting Fitness Costs Associated with Antibiotic Resistance in the Gut: On the Way to Biorestoration of Susceptible Populations. Biomolecules 2024; 14:76. [PMID: 38254676 PMCID: PMC10812938 DOI: 10.3390/biom14010076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/27/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024] Open
Abstract
The acquisition and expression of antibiotic resistance implies changes in bacterial cell physiology, imposing fitness costs. Many human opportunistic pathogenic bacteria, such as those causing urinary tract or bloodstream infections, colonize the gut. In this opinionated review, we will examine the various types of stress that these bacteria might suffer during their intestinal stay. These stresses, and their compensatory responses, probably have a fitness cost, which might be additive to the cost of expressing antibiotic resistance. Such an effect could result in a disadvantage relative to antibiotic susceptible populations that might replace the resistant ones. The opinion proposed in this paper is that the effect of these combinations of fitness costs should be tested in antibiotic resistant bacteria with susceptible ones as controls. This testing might provide opportunities to increase the bacterial gut stress boosting physiological biomolecules or using dietary interventions. This approach to reduce the burden of antibiotic-resistant populations certainly must be answered empirically. In the end, the battle against antibiotic resistance should be won by antibiotic-susceptible organisms. Let us help them prevail.
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Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), 28034 Madrid, Spain
- Network Center for Biomedical Research in Epidemiology and Public Health (CIBER-ESP), 28029 Madrid, Spain
| | - Jerónimo Rodríguez-Beltrán
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), 28034 Madrid, Spain
- Network Center for Biomedical Research in Infectious Diseases (CIBER-INFEC), 28034 Madrid, Spain
| | - Teresa M. Coque
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), 28034 Madrid, Spain
- Network Center for Biomedical Research in Infectious Diseases (CIBER-INFEC), 28034 Madrid, Spain
| | - Rosa del Campo
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), 28034 Madrid, Spain
- Network Center for Biomedical Research in Infectious Diseases (CIBER-INFEC), 28034 Madrid, Spain
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3
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Larabi AB, Masson HLP, Bäumler AJ. Bile acids as modulators of gut microbiota composition and function. Gut Microbes 2023; 15:2172671. [PMID: 36740850 PMCID: PMC9904317 DOI: 10.1080/19490976.2023.2172671] [Citation(s) in RCA: 54] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/16/2023] [Indexed: 02/07/2023] Open
Abstract
Changes in the composition of gut-associated microbial communities are associated with many human illnesses, but the factors driving dysbiosis remain incompletely understood. One factor governing the microbiota composition in the gut is bile. Bile acids shape the microbiota composition through their antimicrobial activity and by activating host signaling pathways that maintain gut homeostasis. Although bile acids are host-derived, their functions are integrally linked to bacterial metabolism, which shapes the composition of the intestinal bile acid pool. Conditions that change the size or composition of the bile acid pool can trigger alterations in the microbiota composition that exacerbate inflammation or favor infection with opportunistic pathogens. Therefore, manipulating the composition or size of the bile acid pool might be a promising strategy to remediate dysbiosis.
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Affiliation(s)
- Anaïs B. Larabi
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA, USA
| | - Hugo L. P. Masson
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA, USA
| | - Andreas J. Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA, USA
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4
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Fang Y, Wu W, Zhao Y, Liu H, Li Z, Li X, Zhang M, Qin Y. Transcriptomic and metabolomic investigation of molecular inactivation mechanisms in Escherichia coli triggered by graphene quantum dots. CHEMOSPHERE 2023; 311:137051. [PMID: 36334733 DOI: 10.1016/j.chemosphere.2022.137051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/26/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Graphene quantum dots (GQDs), a novel broad-spectrum antibacterial agent, are considered potential candidates in the field of biomedical and food safety due to their outstanding antimicrobial properties and excellent biocompatibility. To uncover the molecular regulatory mechanisms underlying the phenotypes, the overall regulation of genes and metabolites in Escherichia coli (E. coli) after GQDs stimulation was investigated by RNA-sequencing and LC-MS. Gene transcription and metabolite expression related to a series of crucial biomolecular processes were influenced by the GQDs stimulation, including biofilm formation, bacterial secretion system, sulfur metabolism and nitrogen metabolism, etc. This study could provide profound insights into the GQDs stress response in E. coli, which would be useful for the development and application of GQDs in food safety.
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Affiliation(s)
- Yan Fang
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Wanfeng Wu
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Yan Zhao
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Haoqiang Liu
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Zongda Li
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Xinbo Li
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China
| | - Minwei Zhang
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China.
| | - Yanan Qin
- College of Life Science & Technology, Xinjiang University, Urumqi, 830017, China; Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi, 830017, China.
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Frequent Occurrence and Metabolic Versatility of Marinifilaceae Bacteria as Key Players in Organic Matter Mineralization in Global Deep Seas. mSystems 2022; 7:e0086422. [PMID: 36342154 PMCID: PMC9765461 DOI: 10.1128/msystems.00864-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Transfer of animal and plant detritus of both terrestrial and marine origins to the deep sea occurs on a global scale. Microorganisms play an important role in mineralizing them therein, but these are yet to be identified in situ. To observe key bacteria involved, we conducted long-term in situ incubation and found that members of the family Marinifilaceae (MF) occurred as some of the most predominant bacteria thriving on the new inputs of plant and animal biomasses in the deep sea in both marginal and oceanic areas. This taxon is diverse and ubiquitous in marine environments. A total of 11 MAGs belonging to MF were retrieved from metagenomic data and diverged into four subgroups in the phylogenomic tree. Based on metagenomic and metatranscriptomic analyses, we described the metabolic features and in situ metabolizing activities of different subgroups. The MF-2 subgroup, which dominates plant detritus-enriched cultures, specializes in polysaccharide degradation and lignin oxidation and has high transcriptional activities of related genes in situ. Intriguingly, members of this subgroup encode a nitrogen fixation pathway to compensate for the shortage of nitrogen sources inside the plant detritus. In contrast, other subgroups dominating the animal tissue-supported microbiomes are distinguished from MF-2 with regard to carbon and nitrogen metabolism and exhibit high transcriptional activity for proteolysis in situ. Despite these metabolic divergences of MF lineages, they show high in situ transcriptional activities for organic fermentation and anaerobic respiration (reductions of metal and/or dimethyl sulfoxide). These results highlight the role of previously unrecognized Marinifilaceae bacteria in organic matter mineralization in marine environments by coupling carbon and nitrogen cycling with metal and sulfur. IMPORTANCE Microbial mineralization of organic matter has a significant impact on the global biogeochemical cycle. This report confirms the role of Marinifilaceae in organic degradation in the oceans, with a contribution to ocean carbon cycling that has previously been underestimated. It was the dominant taxon thriving on plant and animal biomasses in our in situ incubator, as well as in whale falls and wood falls. At least 9 subgroups were revealed, and they were widely distributed in oceans globally but predominant in organic-matter-rich environments, with an average relative abundance of 8.3%. Different subgroups display a preference for the degradation of different macromolecules (polysaccharides, lignin, and protein) and adapt to their environments via special metabolic mechanisms.
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Gehlert FO, Sauerwein T, Weidenbach K, Repnik U, Hallack D, Förstner KU, Schmitz RA. Dual-RNAseq Analysis Unravels Virus-Host Interactions of MetSV and Methanosarcina mazei. Viruses 2022; 14:2585. [PMID: 36423194 PMCID: PMC9694453 DOI: 10.3390/v14112585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/05/2022] [Accepted: 11/19/2022] [Indexed: 11/23/2022] Open
Abstract
Methanosarcina spherical virus (MetSV), infecting Methanosarcina species, encodes 22 genes, but their role in the infection process in combination with host genes has remained unknown. To study the infection process in detail, infected and uninfected M. mazei cultures were compared using dual-RNAseq, qRT-PCRs, and transmission electron microscopy (TEM). The transcriptome analysis strongly indicates a combined role of virus and host genes in replication, virus assembly, and lysis. Thereby, 285 host and virus genes were significantly regulated. Within these 285 regulated genes, a network of the viral polymerase, MetSVORF6, MetSVORF5, MetSVORF2, and the host genes encoding NrdD, NrdG, a CDC48 family protein, and a SSB protein with a role in viral replication was postulated. Ultrastructural analysis at 180 min p.i. revealed many infected cells with virus particles randomly scattered throughout the cytoplasm or attached at the cell surface, and membrane fragments indicating cell lysis. Dual-RNAseq and qRT-PCR analyses suggested a multifactorial lysis reaction in potential connection to the regulation of a cysteine proteinase, a pirin-like protein and a HicB-solo protein. Our study's results led to the first preliminary infection model of MetSV infecting M. mazei, summarizing the key infection steps as follows: replication, assembly, and host cell lysis.
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Affiliation(s)
- Finn O. Gehlert
- Institute for General Microbiology, Christian Albrechts University, 24118 Kiel, Germany
| | - Till Sauerwein
- ZB MED, Information Centre for Life Sciences, 50931 Cologne, Germany
| | - Katrin Weidenbach
- Institute for General Microbiology, Christian Albrechts University, 24118 Kiel, Germany
| | - Urska Repnik
- Central Microscopy, Christian Albrechts University, 24118 Kiel, Germany
| | - Daniela Hallack
- Institute for General Microbiology, Christian Albrechts University, 24118 Kiel, Germany
| | | | - Ruth A. Schmitz
- Institute for General Microbiology, Christian Albrechts University, 24118 Kiel, Germany
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Kim H, Lee DG. Contribution of SOS genes to H 2O 2-induced apoptosis-like death in Escherichia coli. Curr Genet 2021; 67:969-980. [PMID: 34435216 DOI: 10.1007/s00294-021-01204-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 01/07/2023]
Abstract
Hydrogen peroxide (H2O2) is a debriding agent that damages the microbial structure and function by generating various reactive oxygen species (ROS). H2O2-produced hydroxyl radical (OH∙) also exerts oxidative stress on microorganisms. The spread of antibiotic-resistance in bacteria is a serious issue worldwide, and greater efforts are needed to identify and characterize novel antibacterial mechanisms to develop new treatment strategies. Therefore, this study aimed to clarify the relationship between H2O2 and Escherichia coli and to elucidate a novel antibacterial mechanism(s) of H2O2. Following H2O2 exposure, increased levels of 8-hydroxydeoxyguanosine and malondialdehyde indicated that H2O2 accelerates oxidation of bacterial DNA and lipids in E. coli. As oxidative damage worsened, the SOS response was triggered. Cell division arrest and resulting filamentous cells were identified in cells, indicating that LexA was involved in DNA replication. It was also verified that RecA, a representative SOS gene, helps self-cleavage of LexA and acts as a bacterial caspase-like protein. Our findings also showed that dinF is essential to preserve E. coli from H2O2-induced ROS, and furthermore, demonstrated that H2O2-induced SOS response and SOS genes participate differently in guarding E. coli from oxidative stress. As an extreme SOS response is considered apoptosis-like death (ALD) in bacteria, additional experiments were performed to examine the characteristics of ALD. DNA fragmentation and membrane depolarization appeared in H2O2-treated cells, suggesting that H2O2 causes ALD in E. coli. In conclusion, our investigations revealed that ALD is a novel antibacterial mode of action(s) of H2O2 with important contributions from SOS genes.
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Affiliation(s)
- Heesu Kim
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Korea
| | - Dong Gun Lee
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Korea.
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8
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Lee H, Hwang JS, Lee DG. dinF Elicits Nitric Oxide Signaling Induced by Periplanetasin-4 from American Cockroach in Escherichia coli. Curr Microbiol 2021; 78:3550-3561. [PMID: 34313814 DOI: 10.1007/s00284-021-02615-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 07/16/2021] [Indexed: 01/07/2023]
Abstract
Modern antibiotics have been developed with the aim of destroying cellular function; however, the risk of antibiotic-resistance is increasing continuously. As a result, antimicrobial peptide (AMP) is considered a novel strategy to substitute traditional drugs. This study focused on revealing the antibacterial mechanism(s) of periplanetasn-4, an AMP identified from Cockroach. To elucidate whether periplanetasin-4 generates reactive oxygen species (ROS), a crucial stress factor for cell death, intracellular ROS was measured in Escherichia coli. The degree of membrane and DNA damage was determined using the properties that ROS causes oxidative stress to cell components. Unlike normal cell death, membrane depolarization was observed but DNA fragmentation did not occur. In addition, accumulation of nitric oxide (NO), a free radical with high toxicity, was measured and the byproduct of NO also induced severe intracellular damage. Periplanetasin-4-induced NO also impacted on cytosol calcium levels and triggered lipid peroxidation and DNA oxidation. These features were weakened when NO synthesis was interrupted, and this data suggested that perplanetasin-4-induced NO participates in E. coli cell damage. Moreover, this AMP-induced NO stimulates expression of SOS repair proteins and activation of RecA, a bacterial caspase-like protein. Features of nitrosative damage did not occur especially without dinF gene which is associated with oxidative stress. Therefore, it was indicated that when there is a NO signal, dinF promotes cell death. In conclusion, the combined investigations demonstrated that the antibacterial mechanism(s) of periplanetasin-4 was a NO-induced cell death, and dinF gene is closely related to cell death pathway.
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Affiliation(s)
- Heejeong Lee
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Korea
| | - Jae Sam Hwang
- Department of Agricultural Biology, National Academy of Agricultural Science, RDA, Wanju, Republic of Korea
| | - Dong Gun Lee
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Korea.
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The prevalence of the iutA and ibeA genes in Escherichia coli isolates from severe and non-severe patients with bacteremic acute biliary tract infection is significantly different. Gut Pathog 2021; 13:32. [PMID: 34006312 PMCID: PMC8132388 DOI: 10.1186/s13099-021-00429-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 05/12/2021] [Indexed: 12/17/2022] Open
Abstract
Background Although Escherichia coli is the most frequently isolated microorganism in acute biliary tract infections with bacteremia, data regarding its virulence are limited. Results Information on cases of bacteremia in acute biliary tract infection in a retrospective study was collected from 2013 to 2015 at a tertiary care hospital in Japan. Factors related to the severity of infection were investigated, including patient background, phylogenetic typing, and virulence factors of E. coli, such as adhesion, invasion, toxins, and iron acquisition. In total, 72 E. coli strains were identified in 71 cases, most of which primarily belonged to the B2 phylogroup (68.1%). The presence of the iutA gene (77.3% in the non-severe group, 46.4% in the severe group, P = 0.011) and the ibeA gene (9.1% in the non-severe group, and 35.7% in the severe group, P = 0.012) was significantly associated with the severity of infection. Among the patient characteristics, diabetes mellitus with organ involvement and alkaline phosphatase were different in the severe and non-severe groups. Conclusions We showed that bacteremic E. coli strains from acute biliary tract infections belonged to the virulent (B2) phylogroup. The prevalence of the iutA and ibeA genes between the two groups of bacteremia severity was significantly different.
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Kim S, Lee DG. Silver nanoparticles-induced H 2O 2 triggers apoptosis-like death and is associated with dinF in Escherichia coli. Free Radic Res 2021; 55:107-118. [PMID: 33327800 DOI: 10.1080/10715762.2020.1866178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Silver nanoparticles (AgNPs) are the most widely used nanomaterials as antimicrobial agents. AgNPs have been shown to inhibit the growth of and induce apoptosis-like death in Escherichia coli. However, the precise mechanism of AgNPs-induced apoptosis-like death and association with DNA damage-inducible protein F (dinF), a gene of SOS response, is unknown. Here, AgNPs-contributing depletion of intracellular glutathione levels and deactivation of glutathione peroxidase were shown. This step, indicating disruption of the antioxidant system, resulted in overall oxidative stress. Furthermore, DNA oxidation was accompanied, leading to DNA fragmentation. In addition, AgNPs appeared to induce apoptosis-like death via the SOS response. We used sodium pyruvate - an H2O2 quencher - to study the contribution of H2O2, which showed attenuation of AgNPs-induced DNA damage, SOS response, and apoptosis-like death. In dinF mutant, the strain showed a higher degree of DNA damage and apoptotic features. In conclusion, AgNPs mediate apoptosis-like cell death by H2O2-induced oxidative DNA damage. Furthermore, our result demonstrates that dinF participates in this process, which further supports that AgNPs induces SOS response. Our findings may contribute to expanding the new applications of AgNP-based nanomaterials in biomedical fields.
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Affiliation(s)
- Suhyun Kim
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | - Dong Gun Lee
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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11
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Warr AR, Giorgio RT, Waldor MK. Genetic analysis of the role of the conserved inner membrane protein CvpA in EHEC resistance to deoxycholate. J Bacteriol 2020; 203:JB.00661-20. [PMID: 33361192 PMCID: PMC8095453 DOI: 10.1128/jb.00661-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 12/23/2022] Open
Abstract
The function of cvpA, a bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA's genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant's susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse bacterial phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse bacterial species.IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse bacterial phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.
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Affiliation(s)
- Alyson R Warr
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Disease, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K Waldor
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Disease, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
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12
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Memar MY, Yekani M, Celenza G, Poortahmasebi V, Naghili B, Bellio P, Baghi HB. The central role of the SOS DNA repair system in antibiotics resistance: A new target for a new infectious treatment strategy. Life Sci 2020; 262:118562. [PMID: 33038378 DOI: 10.1016/j.lfs.2020.118562] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/15/2020] [Accepted: 10/01/2020] [Indexed: 01/19/2023]
Abstract
Bacteria have a considerable ability and potential to acquire resistance against antimicrobial agents by acting diverse mechanisms such as target modification or overexpression, multidrug transporter systems, and acquisition of drug hydrolyzing enzymes. Studying the mechanisms of bacterial cell physiology is mandatory for the development of novel strategies to control the antimicrobial resistance phenomenon, as well as for the control of infections in clinics. The SOS response is a cellular DNA repair mechanism that has an essential role in the bacterial biologic process involved in resistance to antibiotics. The activation of the SOS network increases the resistance and tolerance of bacteria to stress and, as a consequence, to antimicrobial agents. Therefore, SOS can be an applicable target for the discovery of new antimicrobial drugs. In the present review, we focus on the central role of SOS response in bacterial resistance mechanisms and its potential as a new target for control of resistant pathogens.
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Affiliation(s)
- Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mina Yekani
- Department of Microbiology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Giuseppe Celenza
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | - Vahdat Poortahmasebi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
| | - Behrooz Naghili
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Pierangelo Bellio
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Hossein Bannazadeh Baghi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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Lin J, Lan Z, Hou W, Yang C, Wang D, Zhang M, Zhi H. Identification and fine-mapping of a genetic locus underlying soybean tolerance to SMV infections. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 292:110367. [PMID: 32005375 DOI: 10.1016/j.plantsci.2019.110367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/22/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Soybean mosaic virus (SMV) is a major pathogen causing yield loss. Developing soybean plants tolerant or resistant to SMV is important for mitigating the adverse effects of the viral infection. However, most studies have focused on the resistance to normal SMV strains. Thus, investigations of the resistance or tolerance to the novel recombinant SMV strain have been limited. To address the threat of the recombinant SMV, two soybean parent genotypes with contrasting reactions to the recombinant SMV and 211 F9:11 recombinant inbred lines were evaluated under artificial inoculation conditions. The JD12 plants are resistant to the recombinant SMV, whereas HT is highly tolerant, but still susceptible. Genetic analyses suggested that the resistance of JD12 is controlled by a single dominant gene and the tolerance is a quantitative trait. The QTL mapping results revealed one QTL (qTsmv-13) for resistance and two QTLs (qTsmv-2 and qTsmv-3) for tolerance. A comparison between known resistance genes and the QTLs identified in this study suggested that qTsmv-13 and qTsmv-2 may correspond to Rsv1 and Rsv4, respectively, whereas qTsmv-3 represents a newly identified QTL for SMV tolerance. We further delimited qTsmv-3 to an interval of approximately 86 kb with a map-based cloning strategy. Only two of five candidate genes, Glyma.03G00550 and Glyma.03G00570, varied between the parents. Additionally, Glyma.03G00550, which is a multidrug and toxic compound extrusion transporter gene, is the likely candidate gene for qTsmv-3. In summary, our research opens a new avenue for formulating strategies to breed soybean varieties tolerant to SMV.
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Affiliation(s)
- Jing Lin
- National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, The Key Laboratory of Crop Genetics and Breeding of Hebei, Shijiazhuang 050035, China
| | - Zejun Lan
- National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, The Key Laboratory of Crop Genetics and Breeding of Hebei, Shijiazhuang 050035, China
| | - Wenhuan Hou
- Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, The Key Laboratory of Crop Genetics and Breeding of Hebei, Shijiazhuang 050035, China
| | - Chunyan Yang
- Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, The Key Laboratory of Crop Genetics and Breeding of Hebei, Shijiazhuang 050035, China
| | - Dagang Wang
- Crop Institute of Anhui Academy of Agricultural Sciences /Key Laboratory of Crop Quality Improvement of Anhui Province, Hefei 230031, China
| | - Mengchen Zhang
- Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, The Key Laboratory of Crop Genetics and Breeding of Hebei, Shijiazhuang 050035, China.
| | - Haijian Zhi
- National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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Betts JW, Roth P, Pattrick CA, Southam HM, La Ragione RM, Poole RK, Schatzschneider U. Antibacterial activity of Mn(I) and Re(I) tricarbonyl complexes conjugated to a bile acid carrier molecule. Metallomics 2020; 12:1563-1575. [PMID: 32856674 DOI: 10.1039/d0mt00142b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A bifunctional cholic acid-bis(2-pyridylmethyl)amine (bpa) ligand featuring an amide linker was coordinated to a manganese(i) or rhenium(i) tricarbonyl moiety to give [M(bpacholamide)(CO)3] with M = Mn, Re in good yield and very high purity. Strong antibacterial activity was observed against four strains of methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus, with minimum inhibitory concentrations (MICs) in the range of 2-3.5 μM. No difference in response was observed for the MSSA vs. MRSA strains. Activity was also independent of the nature of the metal center, as the Mn and Re complexes showed essentially identical MIC values. In contrast to some other metal carbonyl complexes, the activity seems to be unrelated to the release of carbon monoxide, as photoactivation of the Mn complex reduced the potency by a factor of 2-8. Both metal complexes were non-toxic in Galleria mellonella larvae at concentrations of up to 100× the MIC value. In vivo testing in Galleria larvae infected with MRSA/MSSA demonstrated a significant increase in overall survival rates from 46% in the control to 88% in the group treated with the metal complexes. ICP-MS analysis showed that the Mn and Re cholamide complexes are efficiently internalized by E. coli cells and do not interfere with membrane integrity, as evident from a lack of release of intracellular ATP. An increased sensitivity was observed in acrB, acrD, and mdt mutants that are defective in multidrug exporters, indicating that the compounds have an intracellular mechanism of action. Furthermore, E. coli mntP mutants defective in the gene encoding an Mn exporter were more sensitive than the wildtype, while inactivation of the regulator that controls expression of the Mn uptake proteins MntP and MntH slightly increased sensitivity to the compound. Single knockout mutants defective in genes linked to bile salt and oxidative stress response (dinF, yiaH, sodA, katE, and soxS) did not show increased sensitivity relative to the wild type. Overall, neither the cholic acid moiety nor the metal-carbonyl fragment alone appear to be responsible for the biological activity observed and thus the search for the primary intracellular target continues.
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Affiliation(s)
- Jono W Betts
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Patrick Roth
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Calum A Pattrick
- Department of Molecular Biology and Biotechnology, The University of Sheffield, UK
| | - Hannah M Southam
- Department of Molecular Biology and Biotechnology, The University of Sheffield, UK
| | - Roberto M La Ragione
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Robert K Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, UK
| | - Ulrich Schatzschneider
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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15
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Kim S, Lee DG. PMAP-23 triggers cell death by nitric oxide-induced redox imbalance in Escherichia coli. Biochim Biophys Acta Gen Subj 2019; 1863:1187-1195. [PMID: 31026481 DOI: 10.1016/j.bbagen.2019.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/15/2019] [Accepted: 04/22/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND Antibiotic resistance is a global problem and there is an urgent need to augment the arsenal against pathogenic bacteria. The emergence of different drug resistant bacteria is threatening human lives to be pushed toward the pre-antibiotic era. Antimicrobial peptides (AMPs) are a host defense component against infectious pathogens in response to innate immunity. PMAP-23, an AMP derived from porcine myeloid, possesses antibacterial activity. It is currently not clear how the antibacterial activity of PMAP-23 is manifested. METHODS The disruptive effect of nitric oxide (NO) on the catalase activity, reactive oxygen species (ROS) production, DNA oxidation and apoptosis-like death were evaluated using the NO generation inhibitor. RESULTS In this investigation, PMAP-23 generates NO in a dose dependent manner. NO deactivated catalase and this antioxidant could not protect Escherichia coli against ROS, especially hydroxyl radical. This redox imbalance was shown to induce oxidative stress, thus leading to DNA strand break. Consequently, PMAP-23 treated E. coli cells resulted in apoptosis-like death. These physiological changes were inhibited when NO generation was inhibited. In the ΔdinF mutant, the levels of DNA strand break sharply increased and the cells were more sensitive to PMAP-23 than wild type. CONCLUSION Our data strongly indicates that PMAP-23 mediates apoptosis-like cell death through affecting intracellular NO homeostasis. Furthermore, our results demonstrate that DinF functioned in protection from oxidative DNA damage. GENERAL SIGNIFICANCE The identification of PMAP-23 antibacterial activity and mechanism provides a promising antibacterial agent, supporting the role of NO in cell death regulation.
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Affiliation(s)
- Suhyun Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Dong Gun Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea.
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16
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Lee H, Lee DG. SOS genes contribute to Bac8c induced apoptosis-like death in Escherichia coli. Biochimie 2019; 157:195-203. [DOI: 10.1016/j.biochi.2018.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/03/2018] [Indexed: 01/12/2023]
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17
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Lee B, Hwang JS, Lee DG. Induction of apoptosis-like death by periplanetasin-2 in Escherichia coli and contribution of SOS genes. Appl Microbiol Biotechnol 2018; 103:1417-1427. [DOI: 10.1007/s00253-018-9561-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/27/2018] [Accepted: 12/01/2018] [Indexed: 02/06/2023]
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18
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Phillips PL, Reyes L, Sampson EM, Murrell EA, Whitlock JA, Progulske-Fox A. Deletion of a conserved transcript PG_RS02100 expressed during logarithmic growth in Porphyromonas gingivalis results in hyperpigmentation and increased tolerance to oxidative stress. PLoS One 2018; 13:e0207295. [PMID: 30419070 PMCID: PMC6231650 DOI: 10.1371/journal.pone.0207295] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 10/29/2018] [Indexed: 01/15/2023] Open
Abstract
The oral obligate anaerobe Porphyromonas gingivalis possesses a small conserved transcript PG_RS02100 of unknown function we previously identified using small RNA-seq analysis as expressed during logarithmic growth. In this study, we sought to determine if PG_RS02100 plays a role in P. gingivalis growth or stress response. We show that a PG_RS02100 deletion mutant’s (W83Δ514) ability to grow under anaerobic conditions was no different than wildtype (W83), but it was better able to survive hydrogen peroxide exposure when cultured under heme limiting growth conditions, and was more aerotolerant when plated on enriched whole blood agar and exposed to atmospheric oxygen. Together, these results indicate that PG_RS02100 plays a role in surviving oxidative stress in actively growing P. gingivalis and that P. gingivalis’ response to exogenous hydrogen peroxide stress is linked to heme availability. Relative qRT-PCR expression analysis of oxyR, trx-1, tpx, sodB, ahpC, dinF, cydB, and frd, in W83Δ514 and W83 in response to 1 h exogenous dioxygen or hydrogen peroxide exposure, when cultured with varying heme availability, support our phenotypic evidence that W83Δ514 has a more highly primed defense system against exogenous peroxide, dioxygen, and heme generated ROS. Interestingly, W83Δ514 turned black faster than W83 when cultured on whole blood agar, suggesting it was able to accumulate heme more rapidly. The mechanism of increased heme acquisition observed in W83Δ514 is not yet known. However, it is clear that PG_RS02100 is involved in modulating the P. gingivalis cell surface in a manner related to survival, particularly against oxidative stress.
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Affiliation(s)
- Priscilla L. Phillips
- Department of Microbiology and Immunology, A.T Still University of Health Sciences, Kirksville, Missouri, United States of America
- * E-mail: (PLP); (APF)
| | - Leticia Reyes
- Department of Pathobiological Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Edith M. Sampson
- Department of Oral Biology, University of Florida, Gainesville, Florida, United States of America
| | - Evan A. Murrell
- Department of Oral Biology, University of Florida, Gainesville, Florida, United States of America
| | - Joan A. Whitlock
- Department of Oral Biology, University of Florida, Gainesville, Florida, United States of America
| | - Ann Progulske-Fox
- Department of Oral Biology, University of Florida, Gainesville, Florida, United States of America
- * E-mail: (PLP); (APF)
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19
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The food-borne pathogen Campylobacter jejuni responds to the bile salt deoxycholate with countermeasures to reactive oxygen species. Sci Rep 2017; 7:15455. [PMID: 29133896 PMCID: PMC5684402 DOI: 10.1038/s41598-017-15379-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/25/2017] [Indexed: 12/25/2022] Open
Abstract
Bile plays an important role in digestion, absorption of fats, and the excretion of waste products, while concurrently providing a critical barrier against colonization by harmful bacteria. Previous studies have demonstrated that gut pathogens react to bile by adapting their protein synthesis. The ability of pathogens to respond to bile is remarkably complex and still incompletely understood. Here we show that Campylobacter jejuni, a leading bacterial cause of human diarrheal illness worldwide, responds to deoxycholate, a component of bile, by altering global gene transcription in a manner consistent with a strategy to mitigate exposure to reactive oxygen stress. More specifically, continuous growth of C. jejuni in deoxycholate was found to: 1) induce the production of reactive oxygen species (ROS); 2) decrease succinate dehydrogenase activity (complex II of the electron transport chain); 3) increase catalase activity that is involved in H2O2 breakdown; and 4) result in DNA strand breaks. Congruently, the addition of 4-hydroxy-TEMPO (TEMPOL), a superoxide dismutase mimic that reacts with superoxide, rescued the growth of C. jejuni cultured in the presence of deoxycholate. We postulate that continuous exposure of a number of enteric pathogens to deoxycholate stimulates a conserved survival response to this stressor.
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20
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The food-borne pathogen Campylobacter jejuni depends on the AddAB DNA repair system to defend against bile in the intestinal environment. Sci Rep 2017; 7:14777. [PMID: 29089630 PMCID: PMC5665897 DOI: 10.1038/s41598-017-14646-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/12/2017] [Indexed: 12/12/2022] Open
Abstract
Accurate repair of DNA damage is crucial to ensure genome stability and cell survival of all organisms. Bile functions as a defensive barrier against intestinal colonization by pathogenic microbes. Campylobacter jejuni, a leading bacterial cause of foodborne illness, possess strategies to mitigate the toxic components of bile. We recently found that growth of C. jejuni in medium with deoxycholate, a component of bile, caused DNA damage consistent with the exposure to reactive oxygen species. We hypothesized that C. jejuni must repair DNA damage caused by reactive oxygen species to restore chromosomal integrity. Our efforts focused on determining the importance of the putative AddAB DNA repair proteins. A C. jejuni addAB mutant demonstrated enhanced sensitivity to deoxycholate and was impaired in DNA double strand break repair. Complementation of the addAB mutant restored resistance to deoxycholate, as well as function of the DNA double strand break repair system. The importance of these findings translated to the natural host, where the AddAB system was found to be required for efficient C. jejuni colonization of the chicken intestine. This research provides new insight into the molecular mechanism utilized by C. jejuni, and possibly other intestinal pathogens, to survive in the presence of bile.
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21
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Karimova DN, Manukhov IV, Gnuchikh EY, Karimov IF, Deryabin DG. Reactive oxygen and nitrogen species’ effect on lux-biosensors based on Escherichia coli and Salmonella typhimurium. APPL BIOCHEM MICRO+ 2016. [DOI: 10.1134/s0003683816030078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Hay AJ, Zhu J. In Sickness and in Health: The Relationships Between Bacteria and Bile in the Human Gut. ADVANCES IN APPLIED MICROBIOLOGY 2016; 96:43-64. [PMID: 27565580 DOI: 10.1016/bs.aambs.2016.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Colonization of a human host with a commensal microbiota has a complex interaction in which bacterial communities provide numerous health benefits to the host. An equilibrium between host and microbiota is kept in check with the help of biliary secretions by the host. Bile, composed primarily of bile salts, promotes digestion. It also provides a barrier between host and bacteria. After bile salts are synthesized in the liver, they are stored in the gallbladder to be released after food intake. The set of host-secreted bile salts is modified by the resident bacteria. Because bile salts are toxic to bacteria, an equilibrium of modified bile salts is reached that allows commensal bacteria to survive, yet rebuffs invading pathogens. In addition to direct toxic effects on cells, bile salts maintain homeostasis as signaling molecules, tuning the immune system. To cause disease, gram-negative pathogenic bacteria have shared strategies to survive this harsh environment. Through exclusion of bile, efflux of bile, and repair of bile-induced damage, these pathogens can successfully disrupt and outcompete the microbiota to activate virulence factors.
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Affiliation(s)
- A J Hay
- University of Pennsylvania, Philadelphia, PA, United States
| | - J Zhu
- University of Pennsylvania, Philadelphia, PA, United States
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23
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Wang HK, Ng YK, Koh E, Yao L, Chien AS, Lin HX, Lee YK. RNA-Seq reveals transcriptomic interactions of Bacillus subtilis natto and Bifidobacterium animalis subsp. lactis in whole soybean solid-state co-fermentation. Food Microbiol 2015; 51:25-32. [PMID: 26187824 DOI: 10.1016/j.fm.2015.04.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/24/2015] [Accepted: 04/20/2015] [Indexed: 11/24/2022]
Abstract
Bifidobacteria are anaerobes and are difficult to culture in conventional fermentation system. It was observed that Bacillus subtilis natto enhanced growth of Bifidobacterium animalis subsp. lactis v9 by about 3-fold in a whole soybean solid-state co-fermentation, in a non-anaerobic condition. For the purpose of understanding the metabolic interactions between Bif. animalis subsp. lactis v9 and Ba. subtilis natto, the transcriptome of Bif. animalis subsp. lactis v9 and Ba. subtilis natto was analyzed in single and mixed cultures using RNA-Seq. Compared with the single culture, 459 genes of Bif. animalis subsp. lactis v9 were up regulated and 21 were down regulated in the mixed culture with Ba. subtilis natto, with more than 2-fold difference. Predictive metagenomic analyses suggested that Ba. subtilis natto up regulated transport functions, complex carbohydrates and amino acid metabolism, DNA repair, oxydative stress-related functions, and cell growth of Bif. animalis subsp. lactis v9. In the mixed culture with Bif. animalis subsp. lactis v9, only 3 transcripts of Ba. subtilis natto were over-expressed and 3115 were under-expressed with more than 2-fold difference. The highest down-regulated genes were those involved in carbohydrate and amino acid metabolism. The data presented here demonstrated a parasitic-like interaction regulated at the transcription level, between Ba. subtilis natto and Bif. animalis subsp. lactis in the mixed culture. The over-expression of genes involved in substrate uptake and metabolism in Bif. animalis subsp. lactis in the mixed culture nevertheless, led to its higher cell concentration in the nutrient rich whole soybean medium.
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Affiliation(s)
- Hai Kuan Wang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, People's Republic of China
| | - Yi Kai Ng
- Department of Microbiology, National University of Singapore, Singapore
| | - Eileen Koh
- Department of Microbiology, National University of Singapore, Singapore
| | - Lina Yao
- Department of Microbiology, National University of Singapore, Singapore
| | - Ang Sze Chien
- Department of Microbiology, National University of Singapore, Singapore
| | - Hui Xin Lin
- Department of Microbiology, National University of Singapore, Singapore
| | - Yuan Kun Lee
- Department of Microbiology, National University of Singapore, Singapore.
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Hovde BT, Deodato CR, Hunsperger HM, Ryken SA, Yost W, Jha RK, Patterson J, Monnat RJ, Barlow SB, Starkenburg SR, Cattolico RA. Genome Sequence and Transcriptome Analyses of Chrysochromulina tobin: Metabolic Tools for Enhanced Algal Fitness in the Prominent Order Prymnesiales (Haptophyceae). PLoS Genet 2015; 11:e1005469. [PMID: 26397803 PMCID: PMC4580454 DOI: 10.1371/journal.pgen.1005469] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/27/2015] [Indexed: 12/11/2022] Open
Abstract
Haptophytes are recognized as seminal players in aquatic ecosystem function. These algae are important in global carbon sequestration, form destructive harmful blooms, and given their rich fatty acid content, serve as a highly nutritive food source to a broad range of eco-cohorts. Haptophyte dominance in both fresh and marine waters is supported by the mixotrophic nature of many taxa. Despite their importance the nuclear genome sequence of only one haptophyte, Emiliania huxleyi (Isochrysidales), is available. Here we report the draft genome sequence of Chrysochromulina tobin (Prymnesiales), and transcriptome data collected at seven time points over a 24-hour light/dark cycle. The nuclear genome of C. tobin is small (59 Mb), compact (∼40% of the genome is protein coding) and encodes approximately 16,777 genes. Genes important to fatty acid synthesis, modification, and catabolism show distinct patterns of expression when monitored over the circadian photoperiod. The C. tobin genome harbors the first hybrid polyketide synthase/non-ribosomal peptide synthase gene complex reported for an algal species, and encodes potential anti-microbial peptides and proteins involved in multidrug and toxic compound extrusion. A new haptophyte xanthorhodopsin was also identified, together with two “red” RuBisCO activases that are shared across many algal lineages. The Chrysochromulina tobin genome sequence provides new information on the evolutionary history, ecology and economic importance of haptophytes. Microalgae are important contributors to global ecological balance, and process nearly half of the world’s carbon each year. Additionally, these organisms are deeply rooted in the earths’ evolutionary history. To better understand why algae are such strong survivors in aquatic environments and to better understand their contribution to global ecology, we sequenced the genome of a microalga that is abundant in both fresh and salt water environments, but poorly represented by current genomic information. We identify protein-coding genes responsible for the synthesis of potential toxins as well as those that produce antibiotics, and describe gene products that enhanced the ability of the alga to use light energy. We observed that a day-night cycle, similar to that found in natural environments, significantly impacts the expression of algal genes whose products are responsible for synthesizing fats—a rich source of nutrition for many other organisms.
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Affiliation(s)
- Blake T. Hovde
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail: (BTH); (RAC)
| | - Chloe R. Deodato
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Heather M. Hunsperger
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Scott A. Ryken
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Will Yost
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Ramesh K. Jha
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Johnathan Patterson
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Raymond J. Monnat
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- University of Washington, Department of Pathology, Seattle, Washington, United States of America
| | - Steven B. Barlow
- Electron Microscope Facility, San Diego State University, San Diego, California, United States of America
| | - Shawn R. Starkenburg
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Rose Ann Cattolico
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (BTH); (RAC)
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25
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Ogawa W, Minato Y, Dodan H, Onishi M, Tsuchiya T, Kuroda T. Characterization of MATE-type multidrug efflux pumps from Klebsiella pneumoniae MGH78578. PLoS One 2015; 10:e0121619. [PMID: 25807080 PMCID: PMC4373734 DOI: 10.1371/journal.pone.0121619] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 02/02/2015] [Indexed: 01/04/2023] Open
Abstract
We previously described the cloning of genes related to drug resistance from Klebsiella pneumoniae MGH78578. Of these, we identified a putative gene encoding a MATE-type multidrug efflux pump, and named it ketM. Escherichia coli KAM32 possessing ketM on a plasmid showed increased minimum inhibitory concentrations for norfloxacin, ciprofloxacin, cefotaxime, acriflavine, Hoechst 33342, and 4',6-diamidino-2-phenyl indole (DAPI). The active efflux of DAPI was observed in E. coli KAM32 possessing ketM on a plasmid. The expression of mRNA for ketM was observed in K. pneumoniae cells, and we subsequently disrupted ketM in K. pneumoniae ATCC10031. However, no significant changes were observed in drug resistance levels between the parental strain ATCC10031 and ketM disruptant, SKYM. Therefore, we concluded that KetM was a multidrug efflux pump, that did not significantly contribute to intrinsic resistance to antimicrobial chemicals in K. pneumoniae. MATE-type transporters are considered to be secondary transporters; therefore, we investigated the coupling cations of KetM. DAPI efflux by KetM was observed when lactate was added to produce a proton motive force, indicating that KetM effluxed substrates using a proton motive force. However, the weak efflux of DAPI by KetM was also noted when NaCl was added to the assay mixture without lactate. This result suggests that KetM may utilize proton and sodium motive forces.
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Affiliation(s)
- Wakano Ogawa
- Department of Microbiology and Biochemistry, Daiichi University of Pharmacy, Fukuoka, Japan
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- * E-mail:
| | - Yusuke Minato
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hayata Dodan
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Motoyasu Onishi
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Tomofusa Tsuchiya
- Department of Microbiology, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
| | - Teruo Kuroda
- Department of Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Ghazaryan L, Tonoyan L, Ashhab AA, Soares MIM, Gillor O. The role of stress in colicin regulation. Arch Microbiol 2014; 196:753-64. [PMID: 25048159 DOI: 10.1007/s00203-014-1017-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 07/05/2014] [Accepted: 07/11/2014] [Indexed: 12/28/2022]
Abstract
Bacteriocins produced by Enterobacteriaceae are high molecular weight toxic proteins that kill target cells through a variety of mechanisms, including pore formation and nucleic acid degradation. What is remarkable about these toxins is that their expression results in death to the producing cells and therefore bacteriocin induction have to be tightly regulated, often confined to times of stress. Information on the regulation of bacteriocins produced by enteric bacteria is sketchy as their expression has only been elucidated in a handful of bacteria. Here, we review the known regulatory mechanisms of enteric bacteriocins and explore the expression of 12 of them in response to various triggers: DNA-damaging agents, stringent response, catabolite repression, oxidative stress, growth phase, osmolarity, cold shock, nutrient deprivation, anaerobiosis and pH stress. Our results indicate that the expression of bacteriocins is mostly confined to mutagenic triggers, while all other triggers tested are limited inducers.
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Affiliation(s)
- Lusine Ghazaryan
- Zuckerberg Institute for Water Research, J. Blaustein Institutes for Desert Research, Ben-Gurion University, 84990, Midreshet Ben-Gurion, Israel
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27
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Baharoglu Z, Mazel D. SOS, the formidable strategy of bacteria against aggressions. FEMS Microbiol Rev 2014; 38:1126-45. [PMID: 24923554 DOI: 10.1111/1574-6976.12077] [Citation(s) in RCA: 257] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 05/01/2014] [Accepted: 05/07/2014] [Indexed: 12/22/2022] Open
Abstract
The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory network found in most bacterial species to address DNA damage. The aim of this review was to point out that beyond being a repair process, SOS induction leads to a very strong but transient response to genotoxic stress, during which bacteria can rearrange and mutate their genome, induce several phenotypic changes through differential regulation of genes, and sometimes acquire characteristics that potentiate bacterial survival and adaptation to changing environments. We review here the causes and consequences of SOS induction, but also how this response can be modulated under various circumstances and how it is connected to the network of other important stress responses. In the first section, we review articles describing the induction of the SOS response at the molecular level. The second section discusses consequences of this induction in terms of DNA repair, changes in the genome and gene expression, and sharing of genomic information, with their effects on the bacteria's life and evolution. The third section is about the fine tuning of this response to fit with the bacteria's 'needs'. Finally, we discuss recent findings linking the SOS response to other stress responses. Under these perspectives, SOS can be perceived as a powerful bacterial strategy against aggressions.
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Affiliation(s)
- Zeynep Baharoglu
- Institut Pasteur, Département Génomes et Génétique, Unité Plasticité du Génome Bactérien, Paris, France; CNRS, UMR3525, Paris, France
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28
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Lu M, Radchenko M, Symersky J, Nie R, Guo Y. Structural insights into H+-coupled multidrug extrusion by a MATE transporter. Nat Struct Mol Biol 2013; 20:1310-7. [PMID: 24141706 PMCID: PMC3825517 DOI: 10.1038/nsmb.2687] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 08/27/2013] [Indexed: 11/09/2022]
Abstract
Multidrug and toxic compound extrusion (MATE) transporters contribute to multidrug resistance by coupling the efflux of drugs to the influx of Na(+) or H(+). Known structures of Na(+)-coupled, extracellular-facing MATE transporters from the NorM subfamily revealed 12 membrane-spanning segments related by a quasi-two-fold rotational symmetry and a multidrug-binding cavity situated near the membrane surface. Here we report the crystal structure of an H(+)-coupled MATE transporter from Bacillus halodurans and the DinF subfamily at 3.2-Å resolution, unveiling a surprisingly asymmetric arrangement of 12 transmembrane helices. We also identified a membrane-embedded substrate-binding chamber by combining crystallographic and biochemical analyses. Our studies further suggested a direct competition between H(+) and substrate during DinF-mediated transport and implied how a MATE transporter alternates between its extracellular- and intracellular-facing conformations to propel multidrug extrusion. Collectively, our results demonstrated heretofore-unrecognized mechanistic diversity among MATE transporters.
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Affiliation(s)
- Min Lu
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
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29
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30
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Barendt S, Lee H, Birch C, Nakano MM, Jones M, Zuber P. Transcriptomic and phenotypic analysis of paralogous spx gene function in Bacillus anthracis Sterne. Microbiologyopen 2013; 2:695-714. [PMID: 23873705 PMCID: PMC3831629 DOI: 10.1002/mbo3.109] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/05/2013] [Accepted: 06/17/2013] [Indexed: 11/15/2022] Open
Abstract
Spx of Bacillus subtilis is a redox-sensitive protein, which, under disulfide stress, interacts with RNA polymerase to activate genes required for maintaining thiol homeostasis. Spx orthologs are highly conserved among low %GC Gram-positive bacteria, and often exist in multiple paralogous forms. In this study, we used B. anthracis Sterne, which harbors two paralogous spx genes, spxA1 and spxA2, to examine the phenotypes of spx null mutations and to identify the genes regulated by each Spx paralog. Cells devoid of spxA1 were sensitive to diamide and hydrogen peroxide, while the spxA1 spoxA2 double mutant was hypersensitive to the thiol-specific oxidant, diamide. Bacillus anthracis Sterne strains expressing spxA1DD or spxA2DD alleles encoding protease-resistant products were used in microarray and quantitative real-time polymerase chain reaction (RT-qPCR) analyses in order to uncover genes under SpxA1, SpxA2, or SpxA1/SpxA2 control. Comparison of transcriptomes identified many genes that were upregulated when either SpxA1DD or SpxA2DD was produced, but several genes were uncovered whose transcript levels increased in only one of the two SpxADD-expression strains, suggesting that each Spx paralog governs a unique regulon. Among genes that were upregulated were those encoding orthologs of proteins that are specifically involved in maintaining intracellular thiol homeostasis or alleviating oxidative stress. Some of these genes have important roles in B. anthracis pathogenesis, and a large number of upregulated hypothetical genes have no homology outside of the B. cereus/thuringiensis group. Microarray and RT-qPCR analyses also unveiled a regulatory link that exists between the two spx paralogous genes. The data indicate that spxA1 and spxA2 are transcriptional regulators involved in relieving disulfide stress but also control a set of genes whose products function in other cellular processes. Bacillus anthracis harbors two paralogs of the global transcriptional regulator of stress response, SpxA. SpxA1 and SpxA2 contribute to disulfide stress tolerance, but only SpxA1 functions in resistance to peroxide. Transcriptome analysis uncovered potential SpxA1 and SpxA2 regulon members, which include genes activated by both paralogs. However, paralog-specific gene activation was also observed. Genes encoding glutamate racemase, CoA disulfide reductase, and products functioning in bacillithiol biosynthesis, are among the genes activated by the SpxA paralogs.
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Affiliation(s)
- Skye Barendt
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health and Science University, Beaverton, Oregon
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31
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The animal food supplement sepiolite promotes a direct horizontal transfer of antibiotic resistance plasmids between bacterial species. Antimicrob Agents Chemother 2013; 57:2651-3. [PMID: 23529735 DOI: 10.1128/aac.02363-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Animal fodder is routinely complemented with antibiotics together with other food supplements to improve growth. For instance, sepiolite is currently used as a dietary coadjuvant in animal feed, as it increases animal growth parameters and improves meat and derived final product quality. This type of food additive has so far been considered innocuous for the development and spread of antibiotic resistance. In this study, we demonstrate that sepiolite promotes the direct horizontal transfer of antibiotic resistance plasmids between bacterial species. The conditions needed for plasmid transfer (sepiolite and friction forces) occur in the digestive tracts of farm animals, which routinely receive sepiolite as a food additive. Furthermore, this effect may be aggravated by the use of antibiotics supplied as growth promoters.
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