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Nair AV, Singh A, Rajmani RS, Chakravortty D. Salmonella Typhimurium employs spermidine to exert protection against ROS-mediated cytotoxicity and rewires host polyamine metabolism to ameliorate its survival in macrophages. Redox Biol 2024; 72:103151. [PMID: 38593631 PMCID: PMC11015157 DOI: 10.1016/j.redox.2024.103151] [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: 02/12/2024] [Revised: 03/11/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
Salmonella infection entails a cascade of attacks and defence measures. After breaching the intestinal epithelial barrier, Salmonella is phagocytosed by macrophages, where the bacteria encounter multiple stresses, to which it employs relevant countermeasures. Our study shows that, in Salmonella, the polyamine spermidine activates a stress response mechanism by regulating critical antioxidant genes. Salmonella Typhimurium mutants for spermidine transport and synthesis cannot mount an antioxidative response, resulting in high intracellular ROS levels. These mutants are also compromised in their ability to be phagocytosed by macrophages. Furthermore, it regulates a novel enzyme in Salmonella, Glutathionyl-spermidine synthetase (GspSA), which prevents the oxidation of proteins in E. coli. Moreover, the spermidine mutants and the GspSA mutant show significantly reduced survival in the presence of hydrogen peroxide in vitro and reduced organ burden in the mouse model of Salmonella infection. Conversely, in macrophages isolated from gp91phox-/- mice, we observed a rescue in the attenuated fold proliferation previously observed upon infection. We found that Salmonella upregulates polyamine biosynthesis in the host through its effectors from SPI-1 and SPI-2, which addresses the attenuated proliferation observed in spermidine transport mutants. Thus, inhibition of this pathway in the host abrogates the proliferation of Salmonella Typhimurium in macrophages. From a therapeutic perspective, inhibiting host polyamine biosynthesis using an FDA-approved chemopreventive drug, D, L-α-difluoromethylornithine (DFMO), reduces Salmonella colonisation and tissue damage in the mouse model of infection while enhancing the survival of infected mice. Therefore, our work provides a mechanistic insight into the critical role of spermidine in stress resistance of Salmonella. It also reveals a bacterial strategy in modulating host metabolism to promote their intracellular survival and shows the potential of DFMO to curb Salmonella infection.
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Affiliation(s)
- Abhilash Vijay Nair
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bengaluru, India
| | - Anmol Singh
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bengaluru, India
| | - R S Rajmani
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bengaluru, India; Adjunct Faculty, School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India.
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2
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Sarkhel R, Priyadarsini S, Mahawar M. Nutrient limitation and oxidative stress induce the promoter of acetate operon in Salmonella Typhimurium. Arch Microbiol 2024; 206:126. [PMID: 38411730 DOI: 10.1007/s00203-024-03863-2] [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: 12/22/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/28/2024]
Abstract
Glyoxylate shunt is an important pathway for microorganisms to survive under multiple stresses. One of its enzymes, malate synthase (encoded by aceB gene), has been widely speculated for its contribution to both the pathogenesis and virulence of various microorganisms. We have previously demonstrated that malate synthase (MS) is required for the growth of Salmonella Typhimurium (S. Typhimurium) under carbon starvation and survival under oxidative stress conditions. The aceB gene is encoded by the acetate operon in S. Typhimurium. We attempted to study the activity of acetate promoter under both the starvation and oxidative stress conditions in a heterologous system. The lac promoter of the pUC19 plasmid was substituted with the putative promoter sequence of the acetate operon of S. Typhimurium upstream to the lacZ gene and transformed the vector construct into E. coli NEBα cells. The transformed cells were subjected to the stress conditions mentioned above. We observed a fourfold increase in the β-galactosidase activity in these cells resulting from the upregulation of the lacZ gene in the stationary phase of cell growth (nutrient deprived) as compared to the mid-log phase. Following exposure of stationary phase cells to hypochlorite-induced oxidative stress, we further observed a 1.6-fold increase in β galactosidase activity. These data suggest the induction of promoter activity of the acetate operon under carbon starvation and oxidative stress conditions. Thus, these observations corroborate our previous findings regarding the upregulation of aceB expression under stressful environments.
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Affiliation(s)
- Ratanti Sarkhel
- ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India
| | - Swagatika Priyadarsini
- ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India.
- Indian Council of Agricultural Research- National Research Centre on Camel, Bikaner, Rajasthan, India.
| | - Manish Mahawar
- ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India.
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Inpanathan S, Ospina-Escobar E, Li VC, Adamji Z, Lackraj T, Cho YH, Porco N, Choy CH, McPhee JB, Botelho RJ. Salmonella actively modulates TFEB in murine macrophages in a growth-phase and time-dependent manner. Microbiol Spectr 2024; 12:e0498122. [PMID: 38051049 PMCID: PMC10783059 DOI: 10.1128/spectrum.04981-22] [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: 12/04/2022] [Accepted: 11/01/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Activation of the host transcription factor TFEB helps mammalian cells adapt to stresses such as starvation and infection by upregulating lysosome, autophagy, and immuno-protective gene expression. Thus, TFEB is generally thought to protect host cells. However, it may also be that pathogenic bacteria like Salmonella orchestrate TFEB in a spatio-temporal manner to harness its functions to grow intracellularly. Indeed, the relationship between Salmonella and TFEB is controversial since some studies showed that Salmonella actively promotes TFEB, while others have observed that Salmonella degrades TFEB and that compounds that promote TFEB restrict bacterial growth. Our work provides a path to resolve these apparent discordant observations since we showed that stationary-grown Salmonella actively delays TFEB after infection, while late-log Salmonella is permissive of TFEB activation. Nevertheless, the exact function of this manipulation remains unclear, but conditions that erase the conditional control of TFEB by Salmonella may be detrimental to the microbe.
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Affiliation(s)
- Subothan Inpanathan
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Erika Ospina-Escobar
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Vanessa Cruz Li
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Zainab Adamji
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Tracy Lackraj
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Youn Hee Cho
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Natasha Porco
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Christopher H. Choy
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Joseph B. McPhee
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Roberto J. Botelho
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
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4
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Indrajith S, Natarajan S, Thangasamy S, Natesan S. Drug Resistance, Characterization and Phylogenetic Discrepancy of Salmonella enterica Isolates from Distinct Sources. Curr Microbiol 2023; 80:314. [PMID: 37544954 DOI: 10.1007/s00284-023-03343-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 05/23/2023] [Indexed: 08/08/2023]
Abstract
Salmonella enterica is one of the foodborne pathogens that can infect humans, spreading from one person to another by contaminated food and water. To identify the pathogenic S. enterica from the contaminated food product, culture-based and molecular identifications, drug resistance profiling, virulence and genetic traits of the strains have been used. Herein, different animal products was subjected to screen for S. enterica prevalence, pathogenic characterization and compared with clinical Salmonella isolates (human). A total of 173 isolates from animal products and 51 isolates from clinical samples were collected. S. Typhi, S. Agona and S. Ohio were predominant serovars in blood, stool and different animal products. Both, clinical [37% (n = 19/51)] and animal product-associated isolates [21% (n = 37/173)] expressed their highest resistance to nalidixic acid. Thirty-one percentage of (n = 16/51) clinical isolates and 12% (n = 21/173) animal food-associated isolates were resistant to multiple classes of antibiotics. Class 1 integrons encoded by S. Typhi, S. Infantis and S. Emek were screened for sequence analysis, the result revealed that the cassettes encoded-aminoglycoside acetyltransferase and dihydrofolate reductase enzymes. Salmonella pathogenicity island-1 encoded-hilA gene was detected most frequently in all the isolates. PFGE profile revealed the genetic traits of the isolates which were closely linked with antibiotic-resistant properties and virulent characteristics. Only S. Enteritidis, collected from different samples had clonal similarities. In summary, drug-resistant pathogenic Salmonella prevalence was observed in the animal product that could be an important alarm to consumers with the risk of enteric fever and it causes the potential risk to public health.
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Affiliation(s)
- Sureka Indrajith
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, Tamil Nadu, 625021, India
| | - Sisubalan Natarajan
- Department of Botany, Bishop Heber College (Autonomous), Affi. To Bharathidasan University, Trichy, Tamil Nadu, 620017, India
| | - Selvankumar Thangasamy
- PG and Research Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, Tamil Nadu, 637501, India
| | - Sivakumar Natesan
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, Tamil Nadu, 625021, India.
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Tsai CN, Massicotte MA, MacNair CR, Perry JN, Brown ED, Coombes BK. Screening under infection-relevant conditions reveals chemical sensitivity in multidrug resistant invasive non-typhoidal Salmonella (iNTS). RSC Chem Biol 2023; 4:600-612. [PMID: 37547457 PMCID: PMC10398353 DOI: 10.1039/d3cb00014a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/30/2023] [Indexed: 08/08/2023] Open
Abstract
Bloodstream infections caused by invasive, non-typhoidal Salmonella (iNTS) are a major global health concern, particularly in Africa where the pathogenic variant of Salmonella Typhimurium sequence type (ST) 313 is dominant. Unlike S. Typhimurium strains that cause gastroenteritis, iNTS strains cause bloodstream infections and are resistant to multiple first-line antibiotics, thus limiting current treatment options. Here, we developed and implemented multiple small molecule screens under physiological, infection-relevant conditions to reveal chemical sensitivities in ST313 and to identify host-directed therapeutics as entry points to drug discovery to combat the clinical burden of iNTS. Screening ST313 iNTS under host-mimicking growth conditions identified 92 compounds with antimicrobial activity despite inherent multidrug resistance. We characterized the antimicrobial activity of the nucleoside analog 3'-azido-3'-deoxythymidine as an exemplary compound from this screen, which depended on bacterial thymidine kinase activity for antimicrobial activity. In a companion macrophage-based screening platform designed to enrich for host-directed therapeutics, we identified three compounds (amodiaquine, berbamine, and indatraline) as actives that required the presence of host cells for antibacterial activity. These three compounds had antimicrobial activity only in the presence of host cells that significantly inhibited intracellular ST313 iNTS replication in macrophages. This work provides evidence that despite high invasiveness and multidrug resistance, ST313 iNTS remains susceptible to unconventional drug discovery approaches.
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Affiliation(s)
- Caressa N Tsai
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
- Michael G. DeGroote Institute for Infectious Disease Research Hamilton ON Canada
| | - Marie-Ange Massicotte
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
- Michael G. DeGroote Institute for Infectious Disease Research Hamilton ON Canada
| | - Craig R MacNair
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
- Michael G. DeGroote Institute for Infectious Disease Research Hamilton ON Canada
| | - Jordyn N Perry
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
| | - Eric D Brown
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
- Michael G. DeGroote Institute for Infectious Disease Research Hamilton ON Canada
| | - Brian K Coombes
- Department of Biochemistry & Biomedical Sciences, McMaster University Hamilton ON L8S 4L8 Canada
- Michael G. DeGroote Institute for Infectious Disease Research Hamilton ON Canada
- Farncombe Family Digestive Health Research Institute Hamilton ON Canada
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Kant S, Liu L, Vazquez-Torres A. The methylglyoxal pathway is a sink for glutathione in Salmonella experiencing oxidative stress. PLoS Pathog 2023; 19:e1011441. [PMID: 37267419 DOI: 10.1371/journal.ppat.1011441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/23/2023] [Indexed: 06/04/2023] Open
Abstract
Salmonella suffer the cytotoxicity of reactive oxygen species generated by the phagocyte NADPH oxidase in the innate host response. Periplasmic superoxide dismutases, catalases and hydroperoxidases detoxify superoxide and hydrogen peroxide (H2O2) synthesized in the respiratory burst of phagocytic cells. Glutathione also helps Salmonella combat the phagocyte NADPH oxidase; however, the molecular mechanisms by which this low-molecular-weight thiol promotes resistance of Salmonella to oxidative stress are currently unknown. We report herein that Salmonella undergoing oxidative stress transcriptionally and functionally activate the methylglyoxal pathway that branches off from glycolysis. Activation of the methylglyoxal pathway consumes a substantial proportion of the glutathione reducing power in Salmonella following exposure to H2O2. The methylglyoxal pathway enables Salmonella to balance glucose utilization with aerobic respiratory outputs. Salmonella take advantage of the metabolic flexibility associated with the glutathione-consuming methylglyoxal pathway to resist reactive oxygen species generated by the enzymatic activity of the phagocyte NADPH oxidase in macrophages and mice. Taken together, glutathione fosters oxidative stress resistance in Salmonella against the antimicrobial actions of the phagocyte NADPH oxidase by promoting the methylglyoxal pathway, an offshoot metabolic adaptation of glycolysis.
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Affiliation(s)
- Sashi Kant
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
| | - Lin Liu
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
| | - Andres Vazquez-Torres
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
- Veterans Affairs, Eastern Colorado Health Care System, Aurora, Colorado, United States of America
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Brito-Santana P, Duque-Pedraza JJ, Bernabéu-Roda LM, Carvia-Hermoso C, Cuéllar V, Fuentes-Romero F, Acosta-Jurado S, Vinardell JM, Soto MJ. Sinorhizobium meliloti DnaJ Is Required for Surface Motility, Stress Tolerance, and for Efficient Nodulation and Symbiotic Nitrogen Fixation. Int J Mol Sci 2023; 24:ijms24065848. [PMID: 36982921 PMCID: PMC10055731 DOI: 10.3390/ijms24065848] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Bacterial surface motility is a complex microbial trait that contributes to host colonization. However, the knowledge about regulatory mechanisms that control surface translocation in rhizobia and their role in the establishment of symbiosis with legumes is still limited. Recently, 2-tridecanone (2-TDC) was identified as an infochemical in bacteria that hampers microbial colonization of plants. In the alfalfa symbiont Sinorhizobium meliloti, 2-TDC promotes a mode of surface motility that is mostly independent of flagella. To understand the mechanism of action of 2-TDC in S. meliloti and unveil genes putatively involved in plant colonization, Tn5 transposants derived from a flagellaless strain that were impaired in 2-TDC-induced surface spreading were isolated and genetically characterized. In one of the mutants, the gene coding for the chaperone DnaJ was inactivated. Characterization of this transposant and newly obtained flagella-minus and flagella-plus dnaJ deletion mutants revealed that DnaJ is essential for surface translocation, while it plays a minor role in swimming motility. DnaJ loss-of-function reduces salt and oxidative stress tolerance in S. meliloti and hinders the establishment of efficient symbiosis by affecting nodule formation efficiency, cellular infection, and nitrogen fixation. Intriguingly, the lack of DnaJ causes more severe defects in a flagellaless background. This work highlights the role of DnaJ in the free-living and symbiotic lifestyles of S. meliloti.
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Affiliation(s)
- Paula Brito-Santana
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Julián J Duque-Pedraza
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Lydia M Bernabéu-Roda
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Cristina Carvia-Hermoso
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Virginia Cuéllar
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Francisco Fuentes-Romero
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Sebastián Acosta-Jurado
- Centro Andaluz de Biología del Desarrollo, CSIC, Junta de Andalucía, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - José-María Vinardell
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - María J Soto
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
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Schulte M, Hensel M, Miskiewicz K. Exposure to stressors and antimicrobials induces cell-autonomous ultrastructural heterogeneity of an intracellular bacterial pathogen. Front Cell Infect Microbiol 2022; 12:963354. [DOI: 10.3389/fcimb.2022.963354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022] Open
Abstract
Despite their clonality, intracellular bacterial pathogens commonly show remarkable physiological heterogeneity during infection of host cells. Physiological heterogeneity results in distinct ultrastructural morphotypes, but the correlation between bacterial physiological state and ultrastructural appearance remains to be established. In this study, we showed that individual cells of Salmonella enterica serovar Typhimurium are heterogeneous in their ultrastructure. Two morphotypes based on the criterion of cytoplasmic density were discriminated after growth under standard culture conditions, as well as during intracellular lifestyle in mammalian host cells. We identified environmental conditions which affect cytoplasmic densities. Using compounds generating oxygen radicals and defined mutant strains, we were able to link the occurrence of an electron-dense ultrastructural morphotype to exposure to oxidative stress and other stressors. Furthermore, by combining ultrastructural analyses of Salmonella during infection and fluorescence reporter analyses for cell viability, we provided evidence that two characterized ultrastructural morphotypes with electron-lucent or electron-dense cytoplasm represent viable cells. Moreover, the presence of electron-dense types is stress related and can be experimentally induced only when amino acids are available in the medium. Our study proposes ultrastructural morphotypes as marker for physiological states of individual intracellular pathogens providing a new marker for single cell analyses.
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Abstract
Bacteria engulfed by phagocytic cells must resist oxidation damage and adapt to cellular hypoxia, but the mechanisms involved in this process are not completely elucidated. Recent work by Kim et al. in the Journal of Biological Chemistry investigated how the intracellular pathogen Salmonella enterica activates gene expression required to counteract oxidative damage. The authors show that this bacterium utilizes host oxidative molecules to activate regulatory proteins that enhance the production of effector molecules, counteracting the host weapon NADPH oxidase and inducing a protective response.
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