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Jang FH, Wong C, Choo J, Aun Sia ES, Mujahid A, Müller M. Increased transfer of trace metals and Vibrio sp. from biodegradable microplastics to catfish Clarias gariepinus. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118850. [PMID: 35041899 DOI: 10.1016/j.envpol.2022.118850] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Microplastic ingestion has been documented in various aquatic species. This causes physical damage, and additionally contaminated microplastics transfer attached pollutants and microbial pathogens to ingesting organisms. Continued metal accumulation can lead to toxicity and adverse health effects; attached microbial pathogens can cause dysbiosis - which lowers host immunity and promotes infections. Catfish, Clarias gariepinus, are a major food source in Southeast Asia, a hotspot of plastic pollution. This study aimed to quantify the transfer of the trace metals copper (Cu) and lead (Pb) -at environmentally relevant concentrations-from microplastics (polyamide 12, PA12, and polylactic acid, PLA) to catfish. Fish were reared for three months and exposed to seven different combinations of feed, supplemented with plastics and metals. At monthly intervals, fish gills, intestines, liver, and edible muscles were analysed for Cu and Pb concentrations using ICP-OES, and the intestines content assessed for Vibrio sp.. Our results showed that biodegradable PLA transferred higher amounts of metals to catfish than expected and also led to increased Vibrio counts in the intestines compared to PA12. Trace metal accumulation was significantly different in varying tissues, with highest concentrations observed in the gills, followed by liver, intestines, and lastly edible muscles. The results of this study further support the existing evidence that microplastics act as efficient shuttles to concentrate and transfer metals. They also indicate that their uptake can cause dysbiosis (increased numbers of Vibrio sp.). Most importantly, however, our study highlights that biodegradable polymers, such as PLA, could actually pose a greater environmental threat when ingested compared to the more common polymers such as PA12.
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Affiliation(s)
- Faddrine Holt Jang
- Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak, 93350, Kuching, Sarawak, Malaysia
| | - Changi Wong
- Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak, 93350, Kuching, Sarawak, Malaysia
| | - Jenny Choo
- Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak, 93350, Kuching, Sarawak, Malaysia
| | - Edwin Sien Aun Sia
- Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak, 93350, Kuching, Sarawak, Malaysia
| | - Aazani Mujahid
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| | - Moritz Müller
- Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak, 93350, Kuching, Sarawak, Malaysia.
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Emwas AH, Szczepski K, Al-Younis I, Lachowicz JI, Jaremko M. Fluxomics - New Metabolomics Approaches to Monitor Metabolic Pathways. Front Pharmacol 2022; 13:805782. [PMID: 35387341 PMCID: PMC8977530 DOI: 10.3389/fphar.2022.805782] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 01/24/2022] [Indexed: 12/18/2022] Open
Abstract
Fluxomics is an innovative -omics research field that measures the rates of all intracellular fluxes in the central metabolism of biological systems. Fluxomics gathers data from multiple different -omics fields, portraying the whole picture of molecular interactions. Recently, fluxomics has become one of the most relevant approaches to investigate metabolic phenotypes. Metabolic flux using 13C-labeled molecules is increasingly used to monitor metabolic pathways, to probe the corresponding gene-RNA and protein-metabolite interaction networks in actual time. Thus, fluxomics reveals the functioning of multi-molecular metabolic pathways and is increasingly applied in biotechnology and pharmacology. Here, we describe the main fluxomics approaches and experimental platforms. Moreover, we summarize recent fluxomic results in different biological systems.
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Affiliation(s)
- Abdul-Hamid Emwas
- King Abdullah University of Science and Technology, Core Labs, Thuwal, Saudi Arabia
| | - Kacper Szczepski
- Smart-Health Initiative (SHI) and Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Inas Al-Younis
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences & Engineering Division (BESE), Thuwal, Saudi Arabia
| | - Joanna Izabela Lachowicz
- Department of Medical Sciences and Public Health, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI) and Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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Chang JD, Vaughan EE, Liu CG, Jelinski JW, Terwilliger AL, Maresso AW. Metabolic profiling reveals nutrient preferences during carbon utilization in Bacillus species. Sci Rep 2021; 11:23917. [PMID: 34903830 PMCID: PMC8669014 DOI: 10.1038/s41598-021-03420-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 11/29/2021] [Indexed: 11/18/2022] Open
Abstract
The genus Bacillus includes species with diverse natural histories, including free-living nonpathogenic heterotrophs such as B. subtilis and host-dependent pathogens such as B. anthracis (the etiological agent of the disease anthrax) and B. cereus, a cause of food poisoning. Although highly similar genotypically, the ecological niches of these three species are mutually exclusive, which raises the untested hypothesis that their metabolism has speciated along a nutritional tract. Here, we developed a pipeline for quantitative total assessment of the use of diverse sources of carbon for general metabolism to better appreciate the "culinary preferences" of three distinct Bacillus species, as well as related Staphylococcus aureus. We show that each species has widely varying metabolic ability to utilize diverse sources of carbon that correlated to their ecological niches. This approach was applied to the growth and survival of B. anthracis in a blood-like environment and find metabolism shifts from sugar to amino acids as the preferred source of energy. Finally, various nutrients in broth and host-like environments are identified that may promote or interfere with bacterial metabolism during infection.
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Affiliation(s)
- James D Chang
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Ellen E Vaughan
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Carmen Gu Liu
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Joseph W Jelinski
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Austen L Terwilliger
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Anthony W Maresso
- The Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA.
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Hafner L, Pichon M, Burucoa C, Nusser SHA, Moura A, Garcia-Garcera M, Lecuit M. Listeria monocytogenes faecal carriage is common and depends on the gut microbiota. Nat Commun 2021; 12:6826. [PMID: 34819495 PMCID: PMC8613254 DOI: 10.1038/s41467-021-27069-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 11/03/2021] [Indexed: 01/15/2023] Open
Abstract
Listeria genus comprises two pathogenic species, L. monocytogenes (Lm) and L. ivanovii, and non-pathogenic species. All can thrive as saprophytes, whereas only pathogenic species cause systemic infections. Identifying Listeria species' respective biotopes is critical to understand the ecological contribution of Listeria virulence. In order to investigate the prevalence and abundance of Listeria species in various sources, we retrieved and analyzed 16S rRNA datasets from MG-RAST metagenomic database. 26% of datasets contain Listeria sensu stricto sequences, and Lm is the most prevalent species, most abundant in soil and host-associated environments, including 5% of human stools. Lm is also detected in 10% of human stool samples from an independent cohort of 900 healthy asymptomatic donors. A specific microbiota signature is associated with Lm faecal carriage, both in humans and experimentally inoculated mice, in which it precedes Lm faecal carriage. These results indicate that Lm faecal carriage is common and depends on the gut microbiota, and suggest that Lm faecal carriage is a crucial yet overlooked consequence of its virulence.
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Affiliation(s)
- Lukas Hafner
- Institut Pasteur, Université de Paris, Inserm U1117, Biology of Infection Unit, 75015, Paris, France
| | - Maxime Pichon
- University Hospital of Poitiers, Infectious Agents Department, Bacteriology and Infection Control Laboratory, 86021, Poitiers, France
- Université de Poitiers, Faculté de Médecine et de Pharmacie, EA 4331, 86022, Poitiers, France
- Université de Poitiers, Faculté de Médecine et de Pharmacie, Inserm U1070, 86022, Poitiers, France
| | - Christophe Burucoa
- University Hospital of Poitiers, Infectious Agents Department, Bacteriology and Infection Control Laboratory, 86021, Poitiers, France
- Université de Poitiers, Faculté de Médecine et de Pharmacie, EA 4331, 86022, Poitiers, France
- Université de Poitiers, Faculté de Médecine et de Pharmacie, Inserm U1070, 86022, Poitiers, France
| | - Sophie H A Nusser
- Institut Pasteur, Université de Paris, Inserm U1117, Biology of Infection Unit, 75015, Paris, France
| | - Alexandra Moura
- Institut Pasteur, Université de Paris, Inserm U1117, Biology of Infection Unit, 75015, Paris, France
- Institut Pasteur, National Reference Center and WHO Collaborating Center Listeria, 75015, Paris, France
| | - Marc Garcia-Garcera
- University of Lausanne, Department of Fundamental Microbiology, 1015, Lausanne, Switzerland
| | - Marc Lecuit
- Institut Pasteur, Université de Paris, Inserm U1117, Biology of Infection Unit, 75015, Paris, France.
- Institut Pasteur, National Reference Center and WHO Collaborating Center Listeria, 75015, Paris, France.
- Necker-Enfants Malades University Hospital, Division of Infectious Diseases and Tropical Medicine, APHP, Institut Imagine, 75006, Paris, France.
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Carbon catabolite repression in pectin digestion by the phytopathogen Dickeya dadantii. J Biol Chem 2021; 298:101446. [PMID: 34826421 PMCID: PMC8688573 DOI: 10.1016/j.jbc.2021.101446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/23/2022] Open
Abstract
The catabolism of pectin from plant cell walls plays a crucial role in the virulence of the phytopathogen Dickeya dadantii. In particular, the timely expression of pel genes encoding major pectate lyases is essential to circumvent the plant defense systems and induce massive pectinolytic activity during the maceration phase. Previous studies identified the role of a positive feedback loop specific to the pectin-degradation pathway, whereas the precise signals controlling the dynamics of pectate lyase expression were unclear. Here, we show that the latter is controlled by a metabolic switch involving both glucose and pectin. We measured the HPLC concentration profiles of the key metabolites related to these two sources of carbon, cAMP and 2-keto-3-deoxygluconate, and developed a dynamic and quantitative model of the process integrating the associated regulators, cAMP receptor protein and KdgR. The model describes the regulatory events occurring at the promoters of two major pel genes, pelE and pelD. It highlights that their activity is controlled by a mechanism of carbon catabolite repression, which directly controls the virulence of D. dadantii. The model also shows that quantitative differences in the binding properties of common regulators at these two promoters resulted in a qualitatively different role of pelD and pelE in the metabolic switch, and also likely in conditions of infection, justifying their evolutionary conservation as separate genes in this species.
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Staphylococcal ClpXP protease targets the cellular antioxidant system to eliminate fitness-compromised cells in stationary phase. Proc Natl Acad Sci U S A 2021; 118:2109671118. [PMID: 34782466 DOI: 10.1073/pnas.2109671118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 01/08/2023] Open
Abstract
The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure. Here, we demonstrate that staphylococci that enter stationary phase following growth in media supplemented with excess glucose, undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the acetate generated as a byproduct of glucose metabolism induces cytoplasmic acidification and extensive protein damage in nondividing cells. Although cell death ensues, it does not occur as a passive consequence of protein damage. Instead, we demonstrate that the expression and activity of the ClpXP protease is induced, resulting in the degeneration of cellular antioxidant capacity and, ultimately, cell death. Under these conditions, inactivation of either clpX or clpP resulted in the extended survival of unfit cells in stationary phase, but at the cost of maintaining population fitness. Finally, we show that cell death from antibiotics that interfere with bacterial protein synthesis can also be partly ascribed to the corresponding increase in clpP expression and activity. The functional conservation of ClpP in eukaryotes and bacteria suggests that ClpP-dependent cell death and fitness maintenance may be a widespread phenomenon in these domains of life.
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Xie X, Hao F, Chen R, Wang J, Wei Y, Liu J, Wang H, Zhang Z, Bai Y, Shao G, Xiong Q, Feng Z. Nicotinamide Adenine Dinucleotide-Dependent Flavin Oxidoreductase of Mycoplasma hyopneumoniae Functions as a Potential Novel Virulence Factor and Not Only as a Metabolic Enzyme. Front Microbiol 2021; 12:747421. [PMID: 34671334 PMCID: PMC8521518 DOI: 10.3389/fmicb.2021.747421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/02/2021] [Indexed: 12/13/2022] Open
Abstract
Mycoplasma hyopneumoniae (Mhp) is the main pathogen that causes enzootic pneumonia, a disease that has a significant impact on the pig industry worldwide. The pathogenesis of enzootic pneumonia, especially possible virulence factors of Mhp, has still not been fully elucidated. The transcriptomic and proteomic analyses of different Mhp strains reported in the literature have revealed differences in virulence, and differences in RNA transcription levels between high- and low-virulence strains initially indicated that nicotinamide adenine dinucleotide (NADH)-dependent flavin oxidoreductase (NFOR) was related to Mhp pathogenicity. Prokaryotic expression and purification of the NFOR protein from Mhp were performed, a rabbit-derived polyclonal antibody against NFOR was prepared, and multiple sequence alignment and evolutionary analyses of Mhp NFOR were performed. For the first time, it was found that the NFOR protein was conserved among all Mhp strains, and NFOR was localized to the cell surface and could adhere to immortalized porcine bronchial epithelial cells (hTERT-PBECs). Adhesion to hTERT-PBECs could be specifically inhibited by an anti-NFOR polyclonal antibody, and the rates of adhesion to both high- and low-virulence strains, 168 and 168L, significantly decreased by more than 40%. Moreover, Mhp NFOR not only recognized and interacted with host fibronectin and plasminogen but also induced cellular oxidative stress and apoptosis in hTERT-PBECs. The release of lactate dehydrogenase by hTERT-PBECs incubated with Mhp NFOR was significantly positively correlated with the virulence of Mhp. Overall, in addition to being a metabolic enzyme related to oxidative stress, NFOR may also function as a potential novel virulence factor of Mhp, thus contributing to the pathogenesis of Mhp; these findings provide new ideas and theoretical support for studying the pathogenic mechanisms of other mycoplasmas.
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Affiliation(s)
- Xing Xie
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Fei Hao
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Rong Chen
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jingjing Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yanna Wei
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jin Liu
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China
| | - Haiyan Wang
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Zhenzhen Zhang
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yun Bai
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Guoqing Shao
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Qiyan Xiong
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Zhixin Feng
- Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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Huang X, Li M, Wang J, Ji L, Geng Y, Ou Y, Yang S, Yin L, Li L, Chen D. Effect of Bacterial Infection on the Edibility of Aquatic Products: The Case of Crayfish ( Procambarus clarkii) Infected With Citrobacter freundii. Front Microbiol 2021; 12:722037. [PMID: 34659149 PMCID: PMC8511708 DOI: 10.3389/fmicb.2021.722037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Aquatic products are one of the world's essential protein sources whose quality and safety are threatened by bacterial diseases. This study investigated the possible effects of bacterial infection on the main edible part, the muscle, in the case of crayfish infected with Citrobacter freundii. The histopathological analysis confirmed that crayfish was sensitive to C. freundii and muscle was one of the target organs. The transcriptome results showed impaired intercellular junctions, downregulation of actin expression, and inhibition of metabolic pathways. Furthermore, transcriptomic results suggest that C. freundii mainly affect muscle structure and nutrition. Subsequent validation experiments confirmed structural damage and nutrient loss in C. freundii infected crayfish muscle. Besides, the spoilage tests showed that C. freundii did not accelerate muscle spoilage and the bacteria had a limited impact on food safety. Therefore, although C. freundii may not be a specific spoilage bacterium, it still affects the edible taste and nutritional value of crayfish muscle. The findings of this study might contribute to further research on C. freundii infection and provide a warning about the adverse effects of bacterial infection on aquatic products.
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Affiliation(s)
- Xiaoli Huang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Minghao Li
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jincheng Wang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Lili Ji
- Meat Processing Key Laboratory of Sichuan Province, Chengdu University, Chengdu, China
| | - Yi Geng
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yangping Ou
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shiyong Yang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Lizi Yin
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Liangyu Li
- Chengdu Academy of Agriculture and Forestry Sciences, Chengdu, China
| | - Defang Chen
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
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Xiao Y, Wang P, Zhu X, Xie Z. Pseudomonas donghuensis HYS gtrA/ B/ II Gene Cluster Contributes to Its Pathogenicity toward Caenorhabditis elegans. Int J Mol Sci 2021; 22:ijms221910741. [PMID: 34639082 PMCID: PMC8509367 DOI: 10.3390/ijms221910741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas donghuensis HYS is more virulent than P. aeruginosa toward Caenorhabditis elegans but the mechanism underlying virulence is unclear. This study is the first to report that the specific gene cluster gtrA/B/II in P. donghuensis HYS is involved in the virulence of this strain toward C. elegans, and there are no reports of GtrA, GtrB and GtrII in any Pseudomonas species. The pathogenicity of P. donghuensis HYS was evaluated using C. elegans as a host. Based on the prediction of virulence factors and comparative genomic analysis of P. donghuensis HYS, we identified 42 specific virulence genes in P. donghuensis HYS. Slow-killing assays of these genes showed that the gtrAB mutation had the greatest effect on the virulence of P. donghuensis HYS, and GtrA, GtrB and GtrII all positively affected P. donghuensis HYS virulence. Two critical GtrII residues (Glu47 and Lys480) were identified in P. donghuensis HYS. Transmission electron microscopy (TEM) showed that GtrA, GtrB and GtrII were involved in the glucosylation of lipopolysaccharide (LPS) O-antigen in P. donghuensis HYS. Furthermore, colony-forming unit (CFU) assays showed that GtrA, GtrB and GtrII significantly enhanced P. donghuensis HYS colonization in the gut of C. elegans, and glucosylation of LPS O-antigen and colonization in the host intestine contributed to the pathogenicity of P. donghuensis HYS. In addition, experiments using the worm mutants ZD101, KU4 and KU25 revealed a correlation between P. donghuensis HYS virulence and the TIR-1/SEK-1/PMK-1 pathways of the innate immune p38 MAPK pathway in C. elegans. In conclusion, these results reveal that the specific virulence gene cluster gtrA/B/II contributes to the unique pathogenicity of HYS compared with other pathogenic Pseudomonas, and that this process also involves C. elegans innate immunity. These findings significantly increase the available information about GtrA/GtrB/GtrII-based virulence mechanisms in the genus Pseudomonas.
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60
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Mucolytic bacteria: prevalence in various pathological diseases. World J Microbiol Biotechnol 2021; 37:176. [PMID: 34519941 DOI: 10.1007/s11274-021-03145-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/07/2021] [Indexed: 02/07/2023]
Abstract
All mucins are highly glycosylated and a key constituent of the mucus layer that is vigilant against pathogens in many organ systems of animals and humans. The viscous layer is organized in bilayers, i.e., an outer layer that is loosely arranged, variable in thickness, home to the commensal microbiota that grows in the complex environment, and an innermost layer that is stratified, non-aspirated, firmly adherent to the epithelial cells and devoid of any microorganisms. The O-glycosylation moiety represents the site of adhesion for pathogens and due to the increase of motility, mucolytic activity, and upregulation of virulence factors, some microorganisms can circumvent the component of the mucus layer and cause disruption in organ homeostasis. A dysbiotic microbiome, defective mucus barrier, and altered immune response often result in various diseases. In this review, paramount emphasis is given to the role played by the bacterial species directly or indirectly involved in mucin degradation, alteration in mucus secretion or its composition or mucin gene expression, which instigates many diseases in the digestive, respiratory, and other organ systems. A systematic view can help better understand the etiology of some complex disorders such as cystic fibrosis, ulcerative colitis and expand our knowledge about mucin degraders to develop new therapeutic approaches to correct ill effects caused by these mucin-dwelling pathogens.
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Li F, Xiong XS, Yang YY, Wang JJ, Wang MM, Tang JW, Liu QH, Wang L, Gu B. Effects of NaCl Concentrations on Growth Patterns, Phenotypes Associated With Virulence, and Energy Metabolism in Escherichia coli BW25113. Front Microbiol 2021; 12:705326. [PMID: 34484145 PMCID: PMC8415458 DOI: 10.3389/fmicb.2021.705326] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022] Open
Abstract
According to the sit-and-wait hypothesis, long-term environmental survival is positively correlated with increased bacterial pathogenicity because high durability reduces the dependence of transmission on host mobility. Many indirectly transmitted bacterial pathogens, such as Mycobacterium tuberculosis and Burkhoderia pseudomallei, have high durability in the external environment and are highly virulent. It is possible that abiotic stresses may activate certain pathways or the expressions of certain genes, which might contribute to bacterial durability and virulence, synergistically. Therefore, exploring how bacterial phenotypes change in response to environmental stresses is important for understanding their potentials in host infections. In this study, we investigated the effects of different concentrations of salt (sodium chloride, NaCl), on survival ability, phenotypes associated with virulence, and energy metabolism of the lab strain Escherichia coli BW25113. In particular, we investigated how NaCl concentrations influenced growth patterns, biofilm formation, oxidative stress resistance, and motile ability. In terms of energy metabolism that is central to bacterial survival, glucose consumption, glycogen accumulation, and trehalose content were measured in order to understand their roles in dealing with the fluctuation of osmolarity. According to the results, trehalose is preferred than glycogen at high NaCl concentration. In order to dissect the molecular mechanisms of NaCl effects on trehalose metabolism, we further checked how the impairment of trehalose synthesis pathway (otsBA operon) via single-gene mutants influenced E. coli durability and virulence under salt stress. After that, we compared the transcriptomes of E. coli cultured at different NaCl concentrations, through which differentially expressed genes (DEGs) and differential pathways with statistical significance were identified, which provided molecular insights into E. coli responses to NaCl concentrations. In sum, this study explored the in vitro effects of NaCl concentrations on E. coli from a variety of aspects and aimed to facilitate our understanding of bacterial physiological changes under salt stress, which might help clarify the linkages between bacterial durability and virulence outside hosts under environmental stresses.
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Affiliation(s)
- Fen Li
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Xue-Song Xiong
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Ying-Ying Yang
- School of Life Sciences, Xuzhou Medical University, Xuzhou, China
| | - Jun-Jiao Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Meng-Meng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jia-Wei Tang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Qing-Hua Liu
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, China
| | - Liang Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China.,Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Bing Gu
- Medical Technology School of Xuzhou Medical University, Xuzhou, China.,Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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Merryman M, Crigler J, Seipelt-Thiemann R, McClelland E. A mutation in C. neoformans mitochondrial NADH dehydrogenase results in increased virulence in mice. Virulence 2021; 11:1366-1378. [PMID: 33103620 PMCID: PMC7588220 DOI: 10.1080/21505594.2020.1831332] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cryptococcus neoformans: (H99W) was serially passaged in the invertebrate wax moth Galleria mellonella fifteen times to study how fungal virulence evolves under selection and whether those adaptations affect virulence. The G. mellonella passaged strain (P15) and the pre-passage H99W strains were used to infect three different host models of C. neoformans: C. elegans, G. mellonella, and Balb/c mice. While there was no difference in survival in the invertebrate models, P15 killed mice faster than H99W through both intratracheal and intravenous routes of infection and mice infected intravenously with P15 showed higher fungal burden in the brain. Characterization of the major virulence factors of C. neoformans found that P15 had increased capsule size, GXM release, and melanization. Whole genome sequencing of P15 and H99W revealed two mutations in P15, an insertion in the promoter region of NADH dehydrogenase (CNAG_09000) and an insertion in the LMP1 gene (CNAG_06765). Both ATP production and metabolic rate were higher in P15 compared to H99W. Quantitative RT-PCR suggested that the increased ATP was due to increased RNA levels of NADH dehydrogenase. Thus, adaptation to growth in hemocytes resulted in increased production of ATP, increased metabolic rate, and increased virulence in mice. This was likely due to differential expression of virulence factors, which skewed the host immune response to a less efficient Th2 response, with higher levels of IL-4, IL-10, and TNF-α in the brain. Overall, serial passage experiments have increased our understanding of how this yeast evolves under innate immune selection pressure.
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Affiliation(s)
- Mitch Merryman
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA
| | - Jacob Crigler
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA
| | | | - Erin McClelland
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA.,M&P Associates , Murfreesboro, TN, USA
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63
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Xu X, Luo Y, Chen H, Song X, Bian Q, Wang X, Liang Q, Zhao J, Li C, Song G, Yang J, Sun L, Jiang J, Wang H, Zhu B, Ye G, Chen L, Tang YW, Jin D. Genomic evolution and virulence association of Clostridioides difficile sequence type 37 (ribotype 017) in China. Emerg Microbes Infect 2021; 10:1331-1345. [PMID: 34125660 PMCID: PMC8253194 DOI: 10.1080/22221751.2021.1943538] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Clostridioides difficile sequence type (ST) 37 (ribotype 017) is one of the most prevalent genotypes circulating in China. However, its genomic evolution and virulence determinants were rarely explored. Whole-genome sequencing, phylogeographic and phylogenetic analyses were conducted for C. difficile ST37 isolates. The 325 ST37 genomes from six continents, including North America (n = 66), South America (n = 4), Oceania (n = 7), Africa (n = 9), Europe (n = 138) and Asia (n = 101), were clustered into six major lineages, with region-dependent distributions, harbouring an array of antibiotic-resistance genes. The ST37 strains from China were divided into four distinct sublineages, showing five importation times and international sources. Isolates associated with severe infections exhibited significantly higher toxin productions, tcdB mRNA levels, and sporulation capacities (P < 0.001). Kyoto Encyclopedia of Genes and Genomes analysis showed 10 metabolic pathways were significantly enriched in the mutations among isolates associated with severe CDI (P < 0.05). Gene mutations in glycometabolism, amino acid metabolism and biosynthesis virtually causing instability in protein activity were correlated positively to the transcription of tcdR and negatively to the expression of toxin repressor genes, ccpA and codY. In summary, our study firstly presented genomic insights into genetic characteristics and virulence association of C. difficile ST37 in China. Gene mutations in certain important metabolic pathways are associated with severe symptoms and correlated with higher virulence in C. difficile ST37 isolates.
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Affiliation(s)
- Xingxing Xu
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China
| | - Yuo Luo
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Huan Chen
- Key Laboratory of Microorganism technology and bioinformatics research of Zhejiang Province, Hangzhou, People's Republic of China.,NMPA Key Laboratory For Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, People's Republic of China
| | - Xiaojun Song
- Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, People's Republic of China
| | - Qiao Bian
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, People's Republic of China
| | - Xianjun Wang
- Department of Laboratory Medicine, Hangzhou First People's Hospital, Hangzhou, People's Republic of China
| | - Qian Liang
- Key Laboratory of Microorganism technology and bioinformatics research of Zhejiang Province, Hangzhou, People's Republic of China.,NMPA Key Laboratory For Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, People's Republic of China
| | - Jianhong Zhao
- Department of Clinical Microbiology, Second Hospital of Hebei Medical University, Hebei Provincial Center for Clinical Laboratories, Shijiazhuang, People's Republic of China
| | - Chunhui Li
- Infection Control Center, Xiangya Hospital of Central South University, Changsha, People's Republic of China
| | - Guangzhong Song
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China
| | - Jun Yang
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China
| | - Lingli Sun
- Key Laboratory of Microorganism technology and bioinformatics research of Zhejiang Province, Hangzhou, People's Republic of China.,NMPA Key Laboratory For Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, People's Republic of China
| | - Jianmin Jiang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, People's Republic of China
| | - Huanying Wang
- Key Laboratory of Microorganism technology and bioinformatics research of Zhejiang Province, Hangzhou, People's Republic of China.,NMPA Key Laboratory For Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, People's Republic of China
| | - Bo Zhu
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Guangyong Ye
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Liang Chen
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA.,Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, USA
| | - Yi-Wei Tang
- Cepheid, Danaher Diagnostic Platform, Shanghai, People's Republic of China
| | - Dazhi Jin
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China.,Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, People's Republic of China
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64
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Genome Scale Analysis Reveals IscR Directly and Indirectly Regulates Virulence Factor Genes in Pathogenic Yersinia. mBio 2021; 12:e0063321. [PMID: 34060331 PMCID: PMC8262890 DOI: 10.1128/mbio.00633-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The iron-sulfur cluster coordinating transcription factor IscR is important for the virulence of Yersinia pseudotuberculosis and a number of other bacterial pathogens. However, the IscR regulon has not yet been defined in any organism. To determine the Yersinia IscR regulon and identify IscR-dependent functions important for virulence, we employed chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq) of Y. pseudotuberculosis expressing or lacking iscR following iron starvation conditions, such as those encountered during infection. We found that IscR binds to the promoters of genes involved in iron homeostasis, reactive oxygen species metabolism, and cell envelope remodeling and regulates expression of these genes in response to iron depletion. Consistent with our previous work, we also found that IscR binds in vivo to the promoter of the Ysc type III secretion system (T3SS) master regulator LcrF, leading to regulation of T3SS genes. Interestingly, comparative genomic analysis suggested over 93% of IscR binding sites were conserved between Y. pseudotuberculosis and the related plague agent Yersinia pestis. Surprisingly, we found that the IscR positively regulated sufABCDSE Fe-S cluster biogenesis pathway was required for T3SS activity. These data suggest that IscR regulates the T3SS in Yersinia through maturation of an Fe-S cluster protein critical for type III secretion, in addition to its known role in activating T3SS genes through LcrF. Altogether, our study shows that iron starvation triggers IscR to coregulate multiple, distinct pathways relevant to promoting bacterial survival during infection.
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65
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Compensatory evolution of Pseudomonas aeruginosa's slow growth phenotype suggests mechanisms of adaptation in cystic fibrosis. Nat Commun 2021; 12:3186. [PMID: 34045458 PMCID: PMC8160344 DOI: 10.1038/s41467-021-23451-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 04/27/2021] [Indexed: 02/04/2023] Open
Abstract
Long-term infection of the airways of cystic fibrosis patients with Pseudomonas aeruginosa is often accompanied by a reduction in bacterial growth rate. This reduction has been hypothesised to increase within-patient fitness and overall persistence of the pathogen. Here, we apply adaptive laboratory evolution to revert the slow growth phenotype of P. aeruginosa clinical strains back to a high growth rate. We identify several evolutionary trajectories and mechanisms leading to fast growth caused by transcriptional and mutational changes, which depend on the stage of adaptation of the strain. Return to high growth rate increases antibiotic susceptibility, which is only partially dependent on reversion of mutations or changes in the transcriptional profile of genes known to be linked to antibiotic resistance. We propose that similar mechanisms and evolutionary trajectories, in reverse direction, may be involved in pathogen adaptation and the establishment of chronic infections in the antibiotic-treated airways of cystic fibrosis patients.
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66
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Antelo GT, Vila AJ, Giedroc DP, Capdevila DA. Molecular Evolution of Transition Metal Bioavailability at the Host-Pathogen Interface. Trends Microbiol 2021; 29:441-457. [PMID: 32951986 PMCID: PMC7969482 DOI: 10.1016/j.tim.2020.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/01/2020] [Accepted: 08/19/2020] [Indexed: 12/21/2022]
Abstract
The molecular evolution of the adaptive response at the host-pathogen interface has been frequently referred to as an 'arms race' between the host and bacterial pathogens. The innate immune system employs multiple strategies to starve microbes of metals. Pathogens, in turn, develop successful strategies to maintain access to bioavailable metal ions under conditions of extreme restriction of transition metals, or nutritional immunity. However, the processes by which evolution repurposes or re-engineers host and pathogen proteins to perform or refine new functions have been explored only recently. Here we review the molecular evolution of several human metalloproteins charged with restricting bacterial access to transition metals. These include the transition metal-chelating S100 proteins, natural resistance-associated macrophage protein-1 (NRAMP-1), transferrin, lactoferrin, and heme-binding proteins. We examine their coevolution with bacterial transition metal acquisition systems, involving siderophores and membrane-spanning metal importers, and the biological specificity of allosteric transcriptional regulatory proteins tasked with maintaining bacterial metallostasis. We also discuss the evolution of metallo-β-lactamases; this illustrates how rapid antibiotic-mediated evolution of a zinc metalloenzyme obligatorily occurs in the context of host-imposed nutritional immunity.
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Affiliation(s)
- Giuliano T Antelo
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), C1405BWE Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro J Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo and Esmeralda, S2002LRK Rosario, Argentina; Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
| | - Daiana A Capdevila
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), C1405BWE Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
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67
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Yoon CK, Kang D, Kim MK, Seok YJ. Vibrio cholerae FruR facilitates binding of RNA polymerase to the fru promoter in the presence of fructose 1-phosphate. Nucleic Acids Res 2021; 49:1397-1410. [PMID: 33476373 PMCID: PMC7897506 DOI: 10.1093/nar/gkab013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/31/2020] [Accepted: 01/06/2021] [Indexed: 12/25/2022] Open
Abstract
In most bacteria, efficient use of carbohydrates is primarily mediated by the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), which concomitantly phosphorylates the substrates during import. Therefore, transcription of the PTS-encoding genes is precisely regulated by transcriptional regulators, depending on the availability of the substrate. Fructose is transported mainly through the fructose-specific PTS (PTSFru) and simultaneously converted into fructose 1-phosphate (F1P). In Gammaproteobacteria such as Escherichia coli and Pseudomonas putida, transcription of the fru operon encoding two PTSFru components, FruA and FruB, and the 1-phosphofructokinase FruK is repressed by FruR in the absence of the inducer F1P. Here, we show that, contrary to the case in other Gammaproteobacteria, FruR acts as a transcriptional activator of the fru operon and is indispensable for the growth of Vibrio cholerae on fructose. Several lines of evidence suggest that binding of the FruR-F1P complex to an operator which is located between the –35 and –10 promoter elements changes the DNA structure to facilitate RNA polymerase binding to the promoter. We discuss the mechanism by which the highly conserved FruR regulates the expression of its target operon encoding the highly conserved PTSFru and FruK in a completely opposite direction among closely related families of bacteria.
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Affiliation(s)
- Chang-Kyu Yoon
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Korea
| | - Deborah Kang
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Korea
| | - Min-Kyu Kim
- Radiation Research Division, Korea Atomic Energy Research Institute, Jeongeup 56212, Korea
| | - Yeong-Jae Seok
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Korea
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68
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Xu X, Chen J, Huang X, Feng S, Zhang X, She F, Wen Y. The Role of a Dipeptide Transporter in the Virulence of Human Pathogen, Helicobacter pylori. Front Microbiol 2021; 12:633166. [PMID: 33732225 PMCID: PMC7959749 DOI: 10.3389/fmicb.2021.633166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/05/2021] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori harbors a dipeptide (Dpp) transporter consisting of a substrate-binding protein (DppA), two permeases (DppB and C), and two ATPases (DppD and F). The Dpp transporter is responsible for the transportation of dipeptides and short peptides. We found that its expression is important for the growth of H. pylori. To understand the role of the Dpp transporter in the pathogenesis of H. pylori, the expression of virulence factors and H. pylori-induced IL-8 production were investigated in H. pylori wild-type and isogenic H. pylori Dpp transporter mutants. We found that expression of CagA was downregulated, while expression of type 4 secretion system (T4SS) components was upregulated in Dpp transporter mutants. The DppA mutant strain expressed higher levels of outer membrane proteins (OMPs), including BabA, HopZ, OipA, and SabA, and showed a higher adhesion level to gastric epithelial AGS cells compared with the H. pylori 26695 wild-type strain. After infection of AGS cells, H. pylori ΔdppA induced a higher level of NF-κB activation and IL-8 production compared with wild-type. These results suggested that in addition to supporting the growth of H. pylori, the Dpp transporter causes bacteria to alter the expression of virulence factors and reduces H. pylori-induced NF-κB activation and IL-8 production in gastric epithelial cells.
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Affiliation(s)
- Xiaohong Xu
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China.,Fujian Medical University Union Hospital, Fuzhou, China
| | - Junwei Chen
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Xiaoxing Huang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Shunhang Feng
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Xiaoyan Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Feifei She
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Yancheng Wen
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
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69
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Comparative phenotypic characterization identifies few differences in the metabolic capacity between Escherichia coli ST131 subclones. Saudi J Biol Sci 2021; 28:762-769. [PMID: 33424365 PMCID: PMC7783844 DOI: 10.1016/j.sjbs.2020.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/11/2020] [Accepted: 11/01/2020] [Indexed: 11/23/2022] Open
Abstract
Background Extraintestinal pathogenic Escherichia coli (ExPEC) is responsible for causing many infections such as urinary tract infections (UTIs). The current dissemination of the multidrug resistant (MDR) ExPEC clone, Escherichia coli sequence type 131 (E. coli ST131), poses a real threat to public health worldwide. This study aimed to determine and compare the metabolic capacity of a collection of ExPEC isolates including ST131, non-ST131 and various ST131 subclones, and sought to assess the association between antimicrobial resistance and metabolic capacity of ST131 isolates. Methods The metabolic activity of forty urine E. coli isolates, collected from in-patients hospitalized at tertiary hospital in Riyadh, was tested using KB009 Hi carbohydrate kit, and then statistically analysed to assess the difference in the metabolic profiles between ST131 and non-ST131 isolates, and between ST131 subclones. Results The data of this study found almost similar metabolic profiles between ST131 and non-ST131, suggesting that ST131 is not a metabolically unique clone of ExPEC. There was also no link between antimicrobial susceptibility profiles and high metabolic capacity of ST131 isolates. Testing the biochemical activity of isolates belonging to ST131 subclones found higher activity of H30 subclone than non-H30 isolates, however it revealed few significant differences between these subclones. Conclusion This study demonstrated no difference in the metabolism of ST131 and non-ST131, although it uncovered the presence of few significant differences in the metabolic capacity between ST131 subclones. Carrying out whole-genome based studies on ST131 and its main subclones is essential to elucidate the genetic factors responsible for the success of particular ST131 subclones.
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70
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Cho JY, Liu R, Macbeth JC, Hsiao A. The Interface of Vibrio cholerae and the Gut Microbiome. Gut Microbes 2021; 13:1937015. [PMID: 34180341 PMCID: PMC8244777 DOI: 10.1080/19490976.2021.1937015] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 02/04/2023] Open
Abstract
The bacterium Vibrio cholerae is the etiologic agent of the severe human diarrheal disease cholera. The gut microbiome, or the native community of microorganisms found in the human gastrointestinal tract, is increasingly being recognized as a factor in driving susceptibility to infection, in vivo fitness, and host interactions of this pathogen. Here, we review a subset of the emerging studies in how gut microbiome structure and microbial function are able to drive V. cholerae virulence gene regulation, metabolism, and modulate host immune responses to cholera infection and vaccination. Improved mechanistic understanding of commensal-pathogen interactions offers new perspectives in the design of prophylactic and therapeutic approaches for cholera control.
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Affiliation(s)
- Jennifer Y. Cho
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Department of Biochemistry, University of California, Riverside, California, USA
| | - Rui Liu
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, California, USA
| | - John C. Macbeth
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Ansel Hsiao
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
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DebRoy S, Aliaga-Tobar V, Galvez G, Arora S, Liang X, Horstmann N, Maracaja-Coutinho V, Latorre M, Hook M, Flores AR, Shelburne SA. Genome-wide analysis of in vivo CcpA binding with and without its key co-factor HPr in the major human pathogen group A Streptococcus. Mol Microbiol 2020; 115:1207-1228. [PMID: 33325565 PMCID: PMC8359418 DOI: 10.1111/mmi.14667] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/02/2020] [Accepted: 12/11/2020] [Indexed: 01/01/2023]
Abstract
Catabolite control protein A (CcpA) is a master regulator of carbon source utilization and contributes to the virulence of numerous medically important Gram‐positive bacteria. Most functional assessments of CcpA, including interaction with its key co‐factor HPr, have been performed in nonpathogenic bacteria. In this study we aimed to identify the in vivo DNA binding profile of CcpA and assess the extent to which HPr is required for CcpA‐mediated regulation and DNA binding in the major human pathogen group A Streptococcus (GAS). Using a combination RNAseq/ChIP‐seq approach, we found that CcpA affects transcript levels of 514 of 1667 GAS genes (31%) whereas direct DNA binding was identified for 105 GAS genes. Three of the directly regulated genes encode the key GAS virulence factors Streptolysin S, PrtS (IL‐8 degrading proteinase), and SpeB (cysteine protease). Mutating CcpA Val301 to Ala (strain 2221‐CcpA‐V301A) abolished interaction between CcpA and HPr and impacted the transcript levels of 205 genes (40%) in the total CcpA regulon. By ChIP‐seq analysis, CcpAV301A bound to DNA from 74% of genes bound by wild‐type CcpA, but generally with lower affinity. These data delineate the direct CcpA regulon and clarify the HPr‐dependent and independent activities of CcpA in a key pathogenic bacterium.
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Affiliation(s)
- Sruti DebRoy
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Victor Aliaga-Tobar
- Facultad de Ciencias Químicas y Farmacéuticas, Advanced Center for Chronic Diseases-ACCDiS, Universidad de Chile, Independencia, Chile.,Laboratorio de Bioingeniería, Instituto de Ciencias de la Ingeniería, Universidad de O'Higgins, Rancagua, Chile
| | - Gabriel Galvez
- Laboratorio de Bioingeniería, Instituto de Ciencias de la Ingeniería, Universidad de O'Higgins, Rancagua, Chile
| | - Srishtee Arora
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Xiaowen Liang
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Nicola Horstmann
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Vinicius Maracaja-Coutinho
- Facultad de Ciencias Químicas y Farmacéuticas, Advanced Center for Chronic Diseases-ACCDiS, Universidad de Chile, Independencia, Chile.,Centro de Modelamiento Molecular, Biofísica y Bioinformática (CM2B2), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Mauricio Latorre
- Laboratorio de Bioingeniería, Instituto de Ciencias de la Ingeniería, Universidad de O'Higgins, Rancagua, Chile.,Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile, Santiago, Chile.,Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Center for Genome Regulation (Fondap 15090007), Universidad de Chile, Santiago, Chile
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Anthony R Flores
- Division of Infectious Diseases, Department of Pediatrics, University of Texas Health Science Center McGovern Medical School, Houston, TX, USA.,Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center McGovern Medical School, Houston, TX, USA
| | - Samuel A Shelburne
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center McGovern Medical School, Houston, TX, USA.,Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston TX, USA
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72
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V. K, Neela VK. Twitching motility of Stenotrophomonas maltophilia under iron limitation: In-silico, phenotypic and proteomic approaches. Virulence 2020; 11:104-112. [PMID: 31957553 PMCID: PMC6984648 DOI: 10.1080/21505594.2020.1713649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/18/2019] [Accepted: 12/02/2019] [Indexed: 10/26/2022] Open
Abstract
This study investigates the twitching ability of 28 clinical and five environmental strains of S. maltophilia grown under iron-depleted condition through in-silico, phenotypic and proteomics approaches. Rapid Annotations using Subsystem Technology (RAST) analysis revealed the presence of 21 targets of type IV pilus shared across S. maltophilia strains K279a, R551-3, D457 and JV3. The macroscopic twitching assay showed that only clinical isolates produced a zone of twitching with a mean of 22.00 mm under normal and 25.00 mm under iron-depleted conditions. (p = 0.002). Environmental isolates did not show any significant twitching activity in both conditions tested. Isobaric Tags for Relative and Absolute Quantification (ITRAQ) analysis showed altered expression of twitching motility protein PilT (99.08-fold change), flagellar biosynthesis protein FliC (20.14-fold change), and fimbrial protein (0.70-fold change) in response to iron-depleted condition. Most of the strains that have the ability to twitch under the normal condition, exhibit enhanced twitching during iron limitation.
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Affiliation(s)
- Kalidasan V.
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Vasantha Kumari Neela
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
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Pettersen VK, Steinsland H, Wiker HG. Distinct Metabolic Features of Pathogenic Escherichia coli and Shigella spp. Determined by Label-Free Quantitative Proteomics. Proteomics 2020; 21:e2000072. [PMID: 33025732 DOI: 10.1002/pmic.202000072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 09/04/2020] [Indexed: 11/07/2022]
Abstract
Escherichia coli and Shigella spp. causing illnesses in humans represent a genotypically and phenotypically diverse group of pathogens. Although E. coli diversity has been studied by comparative genomics, the intra-species variation at the proteome level is currently unknown. The proteomes of 16 pathogenic E. coli, 2 non-pathogenic E. coli, and 5 Shigella strains originating from 18 phylogenetic lineages are investigated. By applying label-free quantitative proteomics on trypsin-digested cell extracts from bacteria grown on blood agar, 4018 proteins are detected, 3285 of which arequantified, and 261 represented virulence factors. Of 753 proteins quantified in all strains, the levels of 153 vary substantially between strains and are functionally associated mostly with stress response and peripheral metabolism. The levels of proteins associated with the central metabolism vary considerably less than the levels of proteins from other metabolic pathways. Hierarchical clustering analysis based on the protein levels results in strains grouping that differ from that obtained by gene-based phylogenetic analysis. Finally, strains of some E. coli pathotypes have more similar protein profiles even when the strains are not genetically closely related. The results suggest that the degree of genetic relatedness may not necessarily be a good predictor of E. coli phenotypic characteristics.
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Affiliation(s)
- Veronika Kuchařová Pettersen
- The Gade Research Group for Infection and Immunity, Department of Clinical Science, University of Bergen, Haukeland universitetssykehus, Laboratoriebygget, Bergen, 5020, Norway
| | - Hans Steinsland
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Alrek helseklynge, blokk D, Årstadveien 17, Bergen, 5020, Norway.,Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen, 5020, Norway
| | - Harald G Wiker
- The Gade Research Group for Infection and Immunity, Department of Clinical Science, University of Bergen, Haukeland universitetssykehus, Laboratoriebygget, Bergen, 5020, Norway
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74
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Abstract
While there has been much study of bacterial gene dispensability, there is a lack of comprehensive genome-scale examinations of the impact of gene deletion on growth in different carbon sources. In this context, a lot can be learned from such experiments in the model microbe Escherichia coli where much is already understood and there are existing tools for the investigation of carbon metabolism and physiology (1). Gene deletion studies have practical potential in the field of antibiotic drug discovery where there is emerging interest in bacterial central metabolism as a target for new antibiotics (2). Furthermore, some carbon utilization pathways have been shown to be critical for initiating and maintaining infection for certain pathogens and sites of infection (3–5). Here, with the use of high-throughput solid medium phenotyping methods, we have generated kinetic growth measurements for 3,796 genes under 30 different carbon source conditions. This data set provides a foundation for research that will improve our understanding of genes with unknown function, aid in predicting potential antibiotic targets, validate and advance metabolic models, and help to develop our understanding of E. coli metabolism. Central metabolism is a topic that has been studied for decades, and yet, this process is still not fully understood in Escherichia coli, perhaps the most amenable and well-studied model organism in biology. To further our understanding, we used a high-throughput method to measure the growth kinetics of each of 3,796 E. coli single-gene deletion mutants in 30 different carbon sources. In total, there were 342 genes (9.01%) encompassing a breadth of biological functions that showed a growth phenotype on at least 1 carbon source, demonstrating that carbon metabolism is closely linked to a large number of processes in the cell. We identified 74 genes that showed low growth in 90% of conditions, defining a set of genes which are essential in nutrient-limited media, regardless of the carbon source. The data are compiled into a Web application, Carbon Phenotype Explorer (CarPE), to facilitate easy visualization of growth curves for each mutant strain in each carbon source. Our experimental data matched closely with the predictions from the EcoCyc metabolic model which uses flux balance analysis to predict growth phenotypes. From our comparisons to the model, we found that, unexpectedly, phosphoenolpyruvate carboxylase (ppc) was required for robust growth in most carbon sources other than most trichloroacetic acid (TCA) cycle intermediates. We also identified 51 poorly annotated genes that showed a low growth phenotype in at least 1 carbon source, which allowed us to form hypotheses about the functions of these genes. From this list, we further characterized the ydhC gene and demonstrated its role in adenosine efflux.
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75
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Golder T, Mukhopadhyay AK, Koley H, Nandy RK. Nonmetabolizable Arabinose Inhibits Vibrio cholerae Growth in M9 Medium with Gluconate as the Sole Carbon Source. Jpn J Infect Dis 2020; 73:343-348. [PMID: 32350213 DOI: 10.7883/yoken.jjid.2019.304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The serogroups O1 and O139 of the marine bacterium Vibrio cholerae are responsible for causing cholera in humans. The pentose sugar arabinose is nonmetabolizable by the pathogen and is present in environmental niches as well as in the human intestine. In this study, arabinose-mediated V. cholerae growth interference was assessed in M9 minimal medium containing gluconate as the sole carbon source in the light of Entner-Doudoroff (ED) pathway, an obligatory metabolic route for gluconate utilization. V. cholerae O1 and O139 strains failed to grow in the presence of ≥ 0.3% arabinose in M9 with 0.2% gluconate, but there was no growth inhibition in the presence of arabinose in M9 with 0.2% glucose. Transcriptional analysis of edd and eda, the genes constituting the ED pathway, showed ~100- and ~17-fold increases, respectively, in M9-gluconate. Minor increases of ~4- and ~2-fold for edd and eda, respectively, were noted in AKI medium supplemented with 0.5% arabinose. The observed arabinose-mediated growth inhibition can contribute toward deepening the understanding of altered phenotypes, if any, via complementation/expression studies in V. cholerae with pBAD vectors and arabinose as an inducer.
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Affiliation(s)
- Taniya Golder
- ICMR-National Institute of Cholera and Enteric Diseases (NICED), India
| | | | - Hemanta Koley
- ICMR-National Institute of Cholera and Enteric Diseases (NICED), India
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76
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Metabolic Feedback Inhibition Influences Metabolite Secretion by the Human Gut Symbiont Bacteroides thetaiotaomicron. mSystems 2020; 5:5/5/e00252-20. [PMID: 32873608 PMCID: PMC7470985 DOI: 10.1128/msystems.00252-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteroides is a highly abundant taxon in the human gut, and Bacteroides thetaiotaomicron (B. theta) is a ubiquitous human symbiont that colonizes the host early in development and persists throughout its life span. The phenotypic plasticity of keystone organisms such as B. theta is important to understand in order to predict phenotype(s) and metabolic interactions under changing nutrient conditions such as those that occur in complex gut communities. Our study shows B. theta prioritizes energy conservation and suppresses secretion of “overflow metabolites” such as organic acids and amino acids when concentrations of acetate are high. Secreted metabolites, especially amino acids, can be a source of nutrients or signals for the host or other microbes in the community. Our study suggests that when metabolically stressed by acetate, B. theta stops sharing with its ecological partners. Microbial metabolism and trophic interactions between microbes give rise to complex multispecies communities in microbe-host systems. Bacteroides thetaiotaomicron (B. theta) is a human gut symbiont thought to play an important role in maintaining host health. Untargeted nuclear magnetic resonance metabolomics revealed B. theta secretes specific organic acids and amino acids in defined minimal medium. Physiological concentrations of acetate and formate found in the human intestinal tract were shown to cause dose-dependent changes in secretion of metabolites known to play roles in host nutrition and pathogenesis. While secretion fluxes varied, biomass yield was unchanged, suggesting feedback inhibition does not affect metabolic bioenergetics but instead redirects carbon and energy to CO2 and H2. Flux balance analysis modeling showed increased flux through CO2-producing reactions under glucose-limiting growth conditions. The metabolic dynamics observed for B. theta, a keystone symbiont organism, underscores the need for metabolic modeling to complement genomic predictions of microbial metabolism to infer mechanisms of microbe-microbe and microbe-host interactions. IMPORTANCEBacteroides is a highly abundant taxon in the human gut, and Bacteroides thetaiotaomicron (B. theta) is a ubiquitous human symbiont that colonizes the host early in development and persists throughout its life span. The phenotypic plasticity of keystone organisms such as B. theta is important to understand in order to predict phenotype(s) and metabolic interactions under changing nutrient conditions such as those that occur in complex gut communities. Our study shows B. theta prioritizes energy conservation and suppresses secretion of “overflow metabolites” such as organic acids and amino acids when concentrations of acetate are high. Secreted metabolites, especially amino acids, can be a source of nutrients or signals for the host or other microbes in the community. Our study suggests that when metabolically stressed by acetate, B. theta stops sharing with its ecological partners.
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77
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Mourão J, Rebelo A, Ribeiro S, Peixe L, Novais C, Antunes P. Atypical Non-H 2S-Producing Monophasic Salmonella Typhimurium ST3478 Strains from Chicken Meat at Processing Stage Are Adapted to Diverse Stresses. Pathogens 2020; 9:E701. [PMID: 32859122 PMCID: PMC7557518 DOI: 10.3390/pathogens9090701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 01/23/2023] Open
Abstract
Poultry products are still an important cause of Salmonella infections worldwide, with an increasingly reported expansion of less-frequent serotypes or atypical strains that are frequently multidrug-resistant. Nevertheless, the ability of Salmonella to survive antimicrobials promoted in the context of antibiotic reducing/replacing and farming rethinking (e.g., organic acids and copper in feed/biocides) has been scarcely explored. We investigated Salmonella occurrence (conventional and molecular assays) among chicken meat at the processing stage (n = 53 batches/29 farms) and characterized their tolerance to diverse stress factors (antibiotics, copper, acid pH, and peracetic acid). Whole-genome sequencing was used to assess adaptive features and to perform comparative analysis. We found a low Salmonella occurrence (4%) and identified S. Enteritidis/ST11 plus atypical non-H2S-producing S. 1,4,[5],12:i:-/ST3478. The ST3478 presented the ability to grow under diverse stresses (antibiotics, copper, and acid-pH). Comparative genomics among ST3478 isolates showed similar antibiotic/metal resistance gene repertoires and identical nonsense phsA thiosulfate reductase mutations (related to H2S-negative phenotype), besides their close phylogenetic relationship by cgMLST and SNPs. This study alerts for the ongoing national and international spread of an emerging monophasic Salmonella Typhimurium clonal lineage with an enlarged ability to survive to antimicrobials/biocides commonly used in poultry production, being unnoticed by conventional Salmonella detection approaches due to an atypical non-H2S-producing phenotype.
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Affiliation(s)
- Joana Mourão
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
- Center for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal
| | - Andreia Rebelo
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
- Scientific Area of Environmental Health, School of Health, Polytechnic Institute of Porto, 4200-465 Porto, Portugal
| | - Sofia Ribeiro
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
| | - Luísa Peixe
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
- ESCMID Food- and Water-borne Infections Study Group (EFWISG), 4010 Basel, Switzerland
| | - Carla Novais
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
- ESCMID Food- and Water-borne Infections Study Group (EFWISG), 4010 Basel, Switzerland
| | - Patrícia Antunes
- UCIBIO/REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (J.M.); (A.R.); (S.R.); (L.P.); (C.N.)
- ESCMID Food- and Water-borne Infections Study Group (EFWISG), 4010 Basel, Switzerland
- Faculty of Nutrition and Food Sciences, University of Porto, 4150-180 Porto, Portugal
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78
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Temporal encoding of bacterial identity and traits in growth dynamics. Proc Natl Acad Sci U S A 2020; 117:20202-20210. [PMID: 32747578 DOI: 10.1073/pnas.2008807117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In biology, it is often critical to determine the identity of an organism and phenotypic traits of interest. Whole-genome sequencing can be useful for this but has limited power for trait prediction. However, we can take advantage of the inherent information content of phenotypes to bypass these limitations. We demonstrate, in clinical and environmental bacterial isolates, that growth dynamics in standardized conditions can differentiate between genotypes, even among strains from the same species. We find that for pairs of isolates, there is little correlation between genetic distance, according to phylogenetic analysis, and phenotypic distance, as determined by growth dynamics. This absence of correlation underscores the challenge in using genomics to infer phenotypes and vice versa. Bypassing this complexity, we show that growth dynamics alone can robustly predict antibiotic responses. These findings are a foundation for a method to identify traits not easily traced to a genetic mechanism.
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79
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González Plaza JJ. Small RNAs as Fundamental Players in the Transference of Information During Bacterial Infectious Diseases. Front Mol Biosci 2020; 7:101. [PMID: 32613006 PMCID: PMC7308464 DOI: 10.3389/fmolb.2020.00101] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Communication shapes life on Earth. Transference of information has played a paramount role on the evolution of all living or extinct organisms since the appearance of life. Success or failure in this process will determine the prevalence or disappearance of a certain set of genes, the basis of Darwinian paradigm. Among different molecules used for transmission or reception of information, RNA plays a key role. For instance, the early precursors of life were information molecules based in primitive RNA forms. A growing field of research has focused on the contribution of small non-coding RNA forms due to its role on infectious diseases. These are short RNA species that carry out regulatory tasks in cis or trans. Small RNAs have shown their relevance in fine tuning the expression and activity of important regulators of essential genes for bacteria. Regulation of targets occurs through a plethora of mechanisms, including mRNA stabilization/destabilization, driving target mRNAs to degradation, or direct binding to regulatory proteins. Different studies have been conducted during the interplay of pathogenic bacteria with several hosts, including humans, animals, or plants. The sRNAs help the invader to quickly adapt to the change in environmental conditions when it enters in the host, or passes to a free state. The adaptation is achieved by direct targeting of the pathogen genes, or subversion of the host immune system. Pathogens trigger also an immune response in the host, which has been shown as well to be regulated by a wide range of sRNAs. This review focuses on the most recent host-pathogen interaction studies during bacterial infectious diseases, providing the perspective of the pathogen.
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Affiliation(s)
- Juan José González Plaza
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czechia
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80
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Panayidou S, Georgiades K, Christofi T, Tamana S, Promponas VJ, Apidianakis Y. Pseudomonas aeruginosa core metabolism exerts a widespread growth-independent control on virulence. Sci Rep 2020; 10:9505. [PMID: 32528034 PMCID: PMC7289854 DOI: 10.1038/s41598-020-66194-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/13/2020] [Indexed: 02/04/2023] Open
Abstract
To assess the role of core metabolism genes in bacterial virulence - independently of their effect on growth - we correlated the genome, the transcriptome and the pathogenicity in flies and mice of 30 fully sequenced Pseudomonas strains. Gene presence correlates robustly with pathogenicity differences among all Pseudomonas species, but not among the P. aeruginosa strains. However, gene expression differences are evident between highly and lowly pathogenic P. aeruginosa strains in multiple virulence factors and a few metabolism genes. Moreover, 16.5%, a noticeable fraction of the core metabolism genes of P. aeruginosa strain PA14 (compared to 8.5% of the non-metabolic genes tested), appear necessary for full virulence when mutated. Most of these virulence-defective core metabolism mutants are compromised in at least one key virulence mechanism independently of auxotrophy. A pathway level analysis of PA14 core metabolism, uncovers beta-oxidation and the biosynthesis of amino-acids, succinate, citramalate, and chorismate to be important for full virulence. Strikingly, the relative expression among P. aeruginosa strains of genes belonging in these metabolic pathways is indicative of their pathogenicity. Thus, P. aeruginosa strain-to-strain virulence variation, remains largely obscure at the genome level, but can be dissected at the pathway level via functional transcriptomics of core metabolism.
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Affiliation(s)
- Stavria Panayidou
- Infection and Cancer Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Kaliopi Georgiades
- Infection and Cancer Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.,Bioinformatics Research Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Theodoulakis Christofi
- Infection and Cancer Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Stella Tamana
- Bioinformatics Research Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Vasilis J Promponas
- Bioinformatics Research Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
| | - Yiorgos Apidianakis
- Infection and Cancer Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
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81
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Dineshkumar K, Aparna V, Wu L, Wan J, Abdelaziz MH, Su Z, Wang S, Xu H. Bacterial bug-out bags: outer membrane vesicles and their proteins and functions. J Microbiol 2020; 58:531-542. [DOI: 10.1007/s12275-020-0026-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 01/08/2023]
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82
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In vitro passage alters virulence, immune activation and proteomic profiles of Burkholderia pseudomallei. Sci Rep 2020; 10:8320. [PMID: 32433516 PMCID: PMC7239947 DOI: 10.1038/s41598-020-64914-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/27/2020] [Indexed: 11/12/2022] Open
Abstract
Serial passage is a problem among many bacterial species, especially those where strains have been stored (banked) for several decades. Prior to banking with an organization such as ATCC, many bacterial strains were passaged for many years, so the characteristics of each strain may be extremely different. This is in addition to any differences in the original host environment. For Burkholderia pseudomallei, the number of serial passages should be carefully defined for each experiment because it undergoes adaptation during the course of serial passages. In the present study, we found that passaged B. pseudomallei fresh clinical isolates and reference strain in Luria-Bertani broth exhibited increased plaque formation, invasion, intracellular replication, Galleria mellonella killing abilities, and cytokine production of host cells. These bacteria also modulated proteomic profiles during in vitro passage. We presume that the modulation of protein expression during in vitro passage caused changes in virulence and immunogenicity phenotypes. Therefore, we emphasize the need for caution regarding the use of data from passaged B. pseudomallei. These findings of phenotypic adaptation during in vitro serial passage can help researchers working on B. pseudomallei and on other species to better understand disparate findings among strains that have been reported for many years.
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83
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Alford MA, Baghela A, Yeung ATY, Pletzer D, Hancock REW. NtrBC Regulates Invasiveness and Virulence of Pseudomonas aeruginosa During High-Density Infection. Front Microbiol 2020; 11:773. [PMID: 32431676 PMCID: PMC7214821 DOI: 10.3389/fmicb.2020.00773] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of nosocomial and chronic infections contributing to morbidity and mortality in cystic fibrosis patients. One of the reasons for its success as a pathogen is its ability to adapt to a broad range of circumstances. Here, we show the involvement of the general nitrogen regulator NtrBC, which is structurally conserved but functionally diverse across species, in pathogenic and adaptive states of P. aeruginosa. The role of NtrB and NtrC was examined in progressive or chronic infections, which revealed that mutants (ΔntrB, ΔntrC, and ΔntrBC) were reduced in their ability to invade and cause damage in a high-density abscess model in vivo. Progressive infections were established with mutants in the highly virulent PA14 genetic background, whereas chronic infections were established with mutants in the less virulent clinical isolate LESB58 genetic background. Characterization of adaptive lifestyles in vitro confirmed that the double ΔntrBC mutant demonstrated >40% inhibition of biofilm formation, a nearly complete inhibition of swarming motility, and a modest decrease and altered surfing motility colony appearance; with the exception of swarming, single mutants generally had more subtle or no changes. Transcriptional profiles of deletion mutants under swarming conditions were defined using RNA-Seq and unveiled dysregulated expression of hundreds of genes implicated in virulence in PA14 and LESB58 chronic lung infections, as well as carbon and nitrogen metabolism. Thus, transcriptional profiles were validated by testing responsiveness of mutants to several key intermediates of central metabolic pathways. These results indicate that NtrBC is a global regulatory system involved in both pathological and physiological processes relevant to the success of Pseudomonas in high-density infection.
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Affiliation(s)
- Morgan A Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Arjun Baghela
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | | | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology, University of Otago, Dunedin, New Zealand
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Wellcome Sanger Institute, Hinxton, United Kingdom
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84
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Garcia JS, Byrd JA, Wong EA. Tissue-, age- and dose-dependent changes in avian β-defensin and LEAP2 mRNA abundance in the intestines of Salmonella Typhimurium challenged broilers. Anim Biotechnol 2020; 32:637-645. [PMID: 32186462 DOI: 10.1080/10495398.2020.1738449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Salmonella is a pathogen normally found in the gastrointestinal tract of poultry. The objective of this study was to determine changes in avian β-defensin (AvBD) and liver-enriched antimicrobial peptide 2 (LEAP2) mRNA following Salmonella challenge. Day of hatch chicks were challenged with 106, 107 or 108 colony-forming units (cfu) of Salmonella typhimurium. There were dose-, tissue- and age-specific changes in AvBD and LEAP2 mRNA. At 1-day post-infection (dpi) there was a transient upregulation of AvBD1, 8, 10 and 12 mRNA in the 108 cfu group. At 5 dpi, all seven AvBD mRNA were downregulated in the ileum, while only AvBD1, 6, 10 and 11 mRNA were downregulated in the jejunum and AvBD6, 8, 10, 12 and 13 were downregulated in the cecum. At 7 dpi, there was downregulation of all seven AvBD mRNA in the duodenum and downregulation of selected AvBD in the jejunum, ileum and cecum. LEAP2 mRNA was downregulated at all doses of Salmonella in the cecum at 1 dpi and in the ileum at 5 dpi. In summary, Salmonella infection caused an initial upregulation followed by a downregulation of AvBD mRNA.
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Affiliation(s)
- Javier S Garcia
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA
| | | | - Eric A Wong
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA
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85
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López-López N, Euba B, Hill J, Dhouib R, Caballero L, Leiva J, Hosmer J, Cuesta S, Ramos-Vivas J, Díez-Martínez R, Schirra HJ, Blank LM, Kappler U, Garmendia J. Haemophilus influenzae Glucose Catabolism Leading to Production of the Immunometabolite Acetate Has a Key Contribution to the Host Airway-Pathogen Interplay. ACS Infect Dis 2020; 6:406-421. [PMID: 31933358 DOI: 10.1021/acsinfecdis.9b00359] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammatory responses and impaired airway immunity, which provides an opportunistic platform for nontypeable Haemophilus influenzae (NTHi) infection. Clinical evidence supports that the COPD airways present increased concentrations of glucose, which may facilitate proliferation of pathogenic bacteria able to use glucose as a carbon source. NTHi metabolizes glucose through respiration-assisted fermentation, leading to the excretion of acetate, formate, and succinate. We hypothesized that such specialized glucose catabolism may be a pathoadaptive trait playing a pivotal role in the NTHi airway infection. To find out whether this is true, we engineered and characterized bacterial mutant strains impaired to produce acetate, formate, or succinate by inactivating the ackA, pflA, and frdA genes, respectively. While the inactivation of the pflA and frdA genes only had minimal physiological effects, the inactivation of the ackA gene affected acetate production and led to reduced bacterial growth, production of lactate under low oxygen tension, and bacterial attenuation in vivo. Moreover, bacterially produced acetate was able to stimulate the expression of inflammatory genes by cultured airway epithelial cells. These results back the notion that the COPD lung supports NTHi growth on glucose, enabling production of fermentative end products acting as immunometabolites at the site of infection. Thus, glucose catabolism may contribute not only to NTHi growth but also to bacterially driven airway inflammation. This information has important implications for developing nonantibiotic antimicrobials, given that airway glucose homeostasis modifying drugs could help prevent microbial infections associated with chronic lung disease.
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Affiliation(s)
| | - Begoña Euba
- Instituto de Agrobiotecnologı́a, CSIC-Gobierno Navarra, 31192 Mutilva, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Julian Hill
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Rabeb Dhouib
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Lucı́a Caballero
- Instituto de Agrobiotecnologı́a, CSIC-Gobierno Navarra, 31192 Mutilva, Spain
| | - José Leiva
- Servicio de Microbiologı́a, Clı́nica Universidad de Navarra, 31008 Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), 31008 Pamplona, Spain
| | - Jennifer Hosmer
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Sergio Cuesta
- Instituto de Agrobiotecnologı́a, CSIC-Gobierno Navarra, 31192 Mutilva, Spain
| | - José Ramos-Vivas
- Servicio Microbiologı́a, Hospital Universitario Marqués de Valdecilla and Instituto de Investigación Marqués de Valdecilla (IDIVAL), 39011 Santander, Spain
- Red Española de Investigación en Patologı́a Infecciosa (REIPI), ISCIII, Madrid, Spain
| | - Roberto Díez-Martínez
- Telum Therapeutics, Centro Europeo de Empresas e Innovación de Navarra (CEIN), 31110 Noáin, Spain
| | - Horst Joachim Schirra
- Centre for Advanced Imaging, The University of Queensland, 4072 St Lucia, Queensland, Australia
| | - Lars M. Blank
- Institute of Applied Biotechnology, RWTH Aachen University, 52074 Aachen, Germany
| | - Ulrike Kappler
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Junkal Garmendia
- Instituto de Agrobiotecnologı́a, CSIC-Gobierno Navarra, 31192 Mutilva, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
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86
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Arenas J, Bossers-de Vries R, Harders-Westerveen J, Buys H, Ruuls-van Stalle LMF, Stockhofe-Zurwieden N, Zaccaria E, Tommassen J, Wells JM, Smith HE, de Greeff A. In vivo transcriptomes of Streptococcus suis reveal genes required for niche-specific adaptation and pathogenesis. Virulence 2020; 10:334-351. [PMID: 30957693 PMCID: PMC6527017 DOI: 10.1080/21505594.2019.1599669] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Streptococcus suis is a Gram-positive bacterium and a zoonotic pathogen residing in the nasopharynx or the gastrointestinal tract of pigs with a potential of causing life-threatening invasive disease. It is endemic in the porcine production industry worldwide, and it is also an emerging human pathogen. After invasion, the pathogen adapts to cause bacteremia and disseminates to different organs including the brain. To gain insights in this process, we infected piglets with a highly virulent strain of S. suis, and bacterial transcriptomes were obtained from blood and different organs (brain, joints, and heart) when animals had severe clinical symptoms of infection. Microarrays were used to determine the genome-wide transcriptional profile at different infection sites and during growth in standard growth medium in vitro. We observed differential expression of around 30% of the Open Reading Frames (ORFs) and infection-site specific patterns of gene expression. Genes with major changes in expression were involved in transcriptional regulation, metabolism, nutrient acquisition, stress defenses, and virulence, amongst others, and results were confirmed for a subset of selected genes using RT-qPCR. Mutants were generated in two selected genes, and the encoded proteins, i.e., NADH oxidase and MetQ, were shown to be important virulence factors in coinfection experiments and in vitro assays. The knowledge derived from this study regarding S. suis gene expression in vivo and identification of virulence factors is important for the development of novel diagnostic and therapeutic strategies to control S. suis disease.
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Affiliation(s)
- Jesús Arenas
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
| | - Ruth Bossers-de Vries
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
| | - José Harders-Westerveen
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
| | - Herma Buys
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
| | | | | | - Edoardo Zaccaria
- b Host Microbe Interactions , Wageningen UR , Wageningen , The Netherlands
| | - Jan Tommassen
- c Department of Molecular Microbiology and Institute of Biomembranes , Utrecht University , Utrecht , The Netherlands
| | - Jerry M Wells
- b Host Microbe Interactions , Wageningen UR , Wageningen , The Netherlands
| | - Hilde E Smith
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
| | - Astrid de Greeff
- a Department of Infection Biology , Wageningen BioVeterinary Research (WBVR) , Lelystad , The Netherlands
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87
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Wang YH. Sialidases From Clostridium perfringens and Their Inhibitors. Front Cell Infect Microbiol 2020; 9:462. [PMID: 31998664 PMCID: PMC6966327 DOI: 10.3389/fcimb.2019.00462] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 12/16/2019] [Indexed: 12/27/2022] Open
Abstract
Clostridium perfringens is an important human and animal pathogen that is the primary causative agent of necrotizing enteritis and enterotoxemia in many types of animals; it causes traumatic gas gangrene in humans and animals and is associated with cases of food poisoning in humans. C. perfringens produces a variety of toxins as well as many enzymes, including three sialidases, NanH, NanI, and NanJ. Sialidases could be important virulence factors that promote the pathogenesis of C. perfringens. Among them, NanI promotes the colonization of C. perfringens in the intestinal tract and enhances the cytotoxic activity and association of several major C. perfringens toxins with host cells. In recent years, studies on the structure and functions of sialidases have yielded interesting results, and the functions of sialic acid and sialidases in bacterial pathogenesis have become a hot research topic. An in-depth understanding and additional studies of sialidases will further elucidate mechanisms of C. perfringens pathogenesis and could promote the development and clinical applications of sialidase inhibitors. This article reviews the structural characteristics, expression regulation, roles of sialidases in C. perfringens pathogenesis, and effects of their inhibitors.
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Affiliation(s)
- Yan-Hua Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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88
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VanMensel D, Chaganti SR, Droppo IG, Weisener CG. Exploring bacterial pathogen community dynamics in freshwater beach sediments: A tale of two lakes. Environ Microbiol 2019; 22:568-583. [PMID: 31736260 DOI: 10.1111/1462-2920.14860] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 11/05/2019] [Accepted: 11/13/2019] [Indexed: 11/28/2022]
Abstract
Pathogenic bacteria associated with freshwater ecosystems can pose significant health risks particularly where recreational water use is popular. Common water quality assessments involve quantifying indicator Escherichia coli within the water column but neglect to consider physical and geochemical factors and contributions from the sediment. In this study, we used high-throughput sequencing to investigate sediment microbial communities at four freshwater public beaches in southern Ontario, Canada and analysed community structure, function, and gene expression with relation to geographical characteristics. Our results indicate that beach sediments at the sediment-water interface could serve as potential sources of bacterial contamination under low-energy environments with tightly packed small sediment particles compared with high-energy environments. Further, the absence of pathogens but expression of pathogenic transcripts suggests occurrence of alternate gene acquisition. Pathogenicity at these locations included expression of Salmonella virulence factors, genes involved in pertussis, and antimicrobial resistance. Finally, we introduce a proposed universal bacterial pathogen model to consider the combined and synergistic processes used by these microbes. To our knowledge, this is the first study of its kind to investigate chemolithotrophic activity related to pathogens within bed sediment at freshwater beaches. This work helps advance current understanding of health risks in these environments.
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Affiliation(s)
- Danielle VanMensel
- Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada
| | - Subba Rao Chaganti
- Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada.,Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Ian G Droppo
- Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Christopher G Weisener
- Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada
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89
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Adu-Gyamfi CG, Savulescu D, George JA, Suchard MS. Indoleamine 2, 3-Dioxygenase-Mediated Tryptophan Catabolism: A Leading Star or Supporting Act in the Tuberculosis and HIV Pas-de-Deux? Front Cell Infect Microbiol 2019; 9:372. [PMID: 31737575 PMCID: PMC6828849 DOI: 10.3389/fcimb.2019.00372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/14/2019] [Indexed: 12/11/2022] Open
Abstract
Progression from latency to active Tuberculosis (TB) disease is mediated by incompletely understood host immune factors. The definitive characteristic of progressive human immunodeficiency virus (HIV) disease is a severe loss in number and function of T lymphocytes. Among the many possible mediators of T lymphocyte loss and ineffective function is the activity of the immune-modulatory enzyme indoleamine 2,3-dioxygenase (IDO). IDO is the rate-limiting enzyme converting tryptophan to kynurenine. IDO activity was initially recognized to mediate tolerance at the foeto-maternal interface. Recently, IDO activity has also been noted to play a critical role in immune tolerance to pathogens. Studies of host immune and metabolic mediators have found IDO activity significantly elevated in HIV and TB disease. In this review, we explore the link between IDO-mediated tryptophan catabolism and the presence of active TB disease in HIV-infected patients. We draw attention to increased IDO activity as a key factor marking the progression from latent to active TB disease in HIV-infected patients.
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Affiliation(s)
- Clement Gascua Adu-Gyamfi
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa.,Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Dana Savulescu
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Jaya Anna George
- Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Melinda Shelley Suchard
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa.,Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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90
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Mucin glycans attenuate the virulence of Pseudomonas aeruginosa in infection. Nat Microbiol 2019; 4:2146-2154. [PMID: 31611643 PMCID: PMC7157942 DOI: 10.1038/s41564-019-0581-8] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 09/09/2019] [Indexed: 12/17/2022]
Abstract
A slimy, hydrated mucus gel lines all wet epithelia in the human body, including the eyes, lungs, and gastrointestinal and urogenital tracts. Mucus forms the first line of defence while housing trillions of microorganisms that constitute the microbiota1. Rarely do these microorganisms cause infections in healthy mucus1, suggesting that mechanisms exist in the mucus layer that regulate virulence. Using the bacterium Pseudomonas aeruginosa and a three-dimensional (3D) laboratory model of native mucus, we determined that exposure to mucus triggers downregulation of virulence genes that are involved in quorum sensing, siderophore biosynthesis and toxin secretion, and rapidly disintegrates biofilms-a hallmark of mucosal infections. This phenotypic switch is triggered by mucins, which are polymers that are densely grafted with O-linked glycans that form the 3D scaffold inside mucus. Here, we show that isolated mucins act at various scales, suppressing distinct virulence pathways, promoting a planktonic lifestyle, reducing cytotoxicity to human epithelia in vitro and attenuating infection in a porcine burn model. Other viscous polymer solutions lack the same effect, indicating that the regulatory function of mucin does not result from its polymeric structure alone. We identify that interactions with P. aeruginosa are mediated by mucin-associated glycans (mucin glycans). By isolating glycans from the mucin backbone, we assessed the collective activity of hundreds of complex structures in solution. Similar to their grafted counterparts, free mucin glycans potently regulate bacterial phenotypes even at relatively low concentrations. This regulatory function is likely dependent on glycan complexity, as monosaccharides do not attenuate virulence. Thus, mucin glycans are potent host signals that 'tame' microorganisms, rendering them less harmful to the host.
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91
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Simoska O, Sans M, Eberlin LS, Shear JB, Stevenson KJ. Electrochemical monitoring of the impact of polymicrobial infections on Pseudomonas aeruginosa and growth dependent medium. Biosens Bioelectron 2019; 142:111538. [DOI: 10.1016/j.bios.2019.111538] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/16/2019] [Accepted: 07/24/2019] [Indexed: 01/04/2023]
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92
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Selection of reference genes for measuring the expression of aiiO in Ochrobactrum quorumnocens A44 using RT-qPCR. Sci Rep 2019; 9:13129. [PMID: 31511547 PMCID: PMC6739375 DOI: 10.1038/s41598-019-49474-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/22/2019] [Indexed: 11/09/2022] Open
Abstract
Reverse transcription quantitative PCR (RT-qPCR), a method of choice for quantification of gene expression changes, requires stably expressed reference genes for normalization of data. So far, no reference genes were established for the Alphaproteobacteria of the genus Ochrobactrum. Here, we determined reference genes for gene expression studies in O. quorumnocens A44. Strain A44 was cultured under 10 different conditions and the stability of expression of 11 candidate genes was evaluated using geNorm, NormFinder and BestKeeper. Most stably expressed genes were found to be rho, gyrB and rpoD. Our results can facilitate the choice of reference genes in the related Ochrobactrum strains. O. quorumnocens A44 is able to inactivate a broad spectrum of N-acyl homoserine lactones (AHLs) - the quorum sensing molecules of many Gram-negative bacteria. This activity is attributed to AiiO hydrolase, yet it remains unclear whether AHLs are the primary substrate of this enzyme. Using the established RT-qPCR setup, we found that the expression of the aiiO gene upon exposure to two AHLs, C6-HLS and 3OC12-HSL, does not change above the 1-fold significance threshold. The implications of this finding are discussed in the light of the role of quorum sensing-interfering enzymes in the host strains.
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93
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Vornhagen J, Sun Y, Breen P, Forsyth V, Zhao L, Mobley HLT, Bachman MA. The Klebsiella pneumoniae citrate synthase gene, gltA, influences site specific fitness during infection. PLoS Pathog 2019; 15:e1008010. [PMID: 31449551 PMCID: PMC6730947 DOI: 10.1371/journal.ppat.1008010] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/06/2019] [Accepted: 07/29/2019] [Indexed: 01/09/2023] Open
Abstract
Klebsiella pneumoniae (Kp), one of the most common causes of healthcare-associated infections, increases patient morbidity, mortality, and hospitalization costs. Kp must acquire nutrients from the host for successful infection; however, the host is able to prevent bacterial nutrient acquisition through multiple systems. This includes the innate immune protein lipocalin 2 (Lcn2), which prevents Kp iron acquisition. To identify novel Lcn2-dependent Kp factors that mediate evasion of nutritional immunity during lung infection, we undertook an InSeq study using a pool of >20,000 transposon mutants administered to Lcn2+/+ and Lcn2-/- mice. Comparing transposon mutant frequencies between mouse genotypes, we identified the Kp citrate synthase, GltA, as potentially interacting with Lcn2, and this novel finding was independently validated. Interestingly, in vitro studies suggest that this interaction is not direct. Given that GltA is involved in oxidative metabolism, we screened the ability of this mutant to use a variety of carbon and nitrogen sources. The results indicated that the gltA mutant has a distinct amino acid auxotrophy rendering it reliant upon glutamate family amino acids for growth. Deletion of Lcn2 from the host leads to increased amino acid levels in bronchioloalveolar lavage fluid, corresponding to increased fitness of the gltA mutant in vivo and ex vivo. Accordingly, addition of glutamate family amino acids to Lcn2+/+ bronchioloalveolar lavage fluid rescued growth of the gltA mutant. Using a variety of mouse models of infection, we show that GltA is an organ-specific fitness factor required for complete fitness in the spleen, liver, and gut, but dispensable in the bloodstream. Similar to bronchioloalveolar lavage fluid, addition of glutamate family amino acids to Lcn2+/+ organ lysates was sufficient to rescue the loss of gltA. Together, this study describes a critical role for GltA in Kp infection and provides unique insight into how metabolic flexibility impacts bacterial fitness during infection. The bacteria Klebsiella pneumoniae (Kp) is an important cause of infection in healthcare settings. These infections can be difficult to treat, as they frequently occur in chronically ill patients and the bacteria have the ability to acquire multiple antibiotic resistance markers. Kp is a common colonizer of the intestinal tract in hospitalized patients, and can progress to infections of the bloodstream, respiratory, and urinary tract. However, the bacterial factors that allow Kp to replicate in these different body sites are unclear. In this study, we found that the Kp citrate synthase, GltA, enables bacterial replication in the lung and intestine by enhancing the ability of Kp to use diverse nutrients in a mechanism known as metabolic flexibility. Kp lacking GltA require specific amino acids that are abundant in blood, but not other body sites. The work in this study provides novel insight into why Kp is a successful hospital pathogen that can colonize and infect multiple body sites.
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Affiliation(s)
- Jay Vornhagen
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Yuang Sun
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Paul Breen
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Valerie Forsyth
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, United States of America
| | - Lili Zhao
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, United States of America
| | - Harry L T Mobley
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, United States of America
| | - Michael A Bachman
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
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Link between Heterotrophic Carbon Fixation and Virulence in the Porcine Lung Pathogen Actinobacillus pleuropneumoniae. Infect Immun 2019; 87:IAI.00768-18. [PMID: 31285248 DOI: 10.1128/iai.00768-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 06/24/2019] [Indexed: 01/01/2023] Open
Abstract
Actinobacillus pleuropneumoniae is a capnophilic pathogen of the porcine respiratory tract lacking enzymes of the oxidative branch of the tricarboxylic acid (TCA) cycle. We previously claimed that A. pleuropneumoniae instead uses the reductive branch in order to generate energy and metabolites. Here, we show that bicarbonate and oxaloacetate supported anaerobic growth of A. pleuropneumoniae Isotope mass spectrometry revealed heterotrophic fixation of carbon from stable isotope-labeled bicarbonate by A. pleuropneumoniae, which was confirmed by nano-scale secondary ion mass spectrometry at a single-cell level. By gas chromatography-combustion-isotope ratio mass spectrometry we could further show that the labeled carbon atom is mainly incorporated into the amino acids aspartate and lysine, which are derived from the TCA metabolite oxaloacetate. We therefore suggest that carbon fixation occurs at the interface of glycolysis and the reductive branch of the TCA cycle. The heme precursor δ-aminolevulinic acid supported growth of A. pleuropneumoniae, similar to bicarbonate, implying that anaplerotic carbon fixation is needed for heme synthesis. However, deletion of potential carbon-fixing enzymes, including PEP-carboxylase (PEPC), PEP-carboxykinase (PEPCK), malic enzyme, and oxaloacetate decarboxylase, as well as various combinations thereof, did not affect carbon fixation. Interestingly, generation of a deletion mutant lacking all four enzymes was not possible, suggesting that carbon fixation in A. pleuropneumoniae is an essential metabolic pathway controlled by a redundant set of enzymes. A double deletion mutant lacking PEPC and PEPCK was not impaired in carbon fixation in vitro but showed reduction of virulence in a pig infection model.
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95
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Litvak Y, Bäumler AJ. Microbiota-Nourishing Immunity: A Guide to Understanding Our Microbial Self. Immunity 2019; 51:214-224. [DOI: 10.1016/j.immuni.2019.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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96
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Xie G, Zeng M, You J, Xie Z. Pseudomonas donghuensis HYS virulence towards Caenorhabditis elegans is regulated by the Cbr/Crc system. Sci Rep 2019; 9:8772. [PMID: 31217473 PMCID: PMC6584532 DOI: 10.1038/s41598-019-45145-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/03/2019] [Indexed: 12/29/2022] Open
Abstract
Pseudomonas donghuensis HYS is the type strain of a recently identified species, P. donghuensis, which has pathogenic potential with an unclear virulence mechanism. In this study, we used Caenorhabditis elegans as a host to explore the virulence mechanism of P. donghuensis HYS. Based on a correlation between P. donghuensis HYS virulence and its repellence property, we identified 68 potential virulence-related genes, among them the Cbr/Crc system, which regulates the virulence of prokaryotic microorganisms. Slow-killing assays indicated that cbrA, cbrB, or specific sRNA-encoding genes all affected P. donghuensis virulence positively, whereas crc affected it negatively. Transcriptome analyses demonstrated that the Cbr/Crc system played an important role in the pathogenesis of P. donghuensis. In addition, experiments using the worm mutant KU25 pmk-1(km25) showed a correlation between P. donghuensis HYS virulence and the PMK-1/p38 MAPK pathway in C. elegans. In conclusion, our data show that Crc plays a novel role in the Cbr/Crc system, and the P. donghuensis virulence phenotype therefore differs from that of P. aeruginosa. This process also involves C. elegans innate immunity. These findings significantly increase the available information about Cbr/Crc-based virulence mechanisms in the genus Pseudomonas.
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Affiliation(s)
- Guanfang Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Wuhan University, Wuhan, 430072, P.R. China
| | - Man Zeng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Wuhan University, Wuhan, 430072, P.R. China
| | - Jia You
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Wuhan University, Wuhan, 430072, P.R. China
| | - Zhixiong Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Wuhan University, Wuhan, 430072, P.R. China.
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97
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Abstract
This essay is written from the vantage point of the microbial world. While the focus of much thought in the microbial pathogenesis and infectious diseases fields has been on the impact of host-microbe interaction on the host, here we ask questions about what happens to the microbe. This essay is written from the vantage point of the microbial world. While the focus of much thought in the microbial pathogenesis and infectious diseases fields has been on the impact of host-microbe interaction on the host, here we ask questions about what happens to the microbe. What are the costs and benefits for microbes of having the capacity for virulence? Our exploration of this topic leads us to conclude that virulence confers very few benefits for microbes, unless disease is necessary for microbial survival through host-to-host spread. In fact, the capacity for virulence is often fraught with risk for microbes, including host dependence and the threat of extinction. The costs of virulence may explain why, relative to their enormous numbers in nature, very few microbes are actually associated with human and animal disease.
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98
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Ross AA, Rodrigues Hoffmann A, Neufeld JD. The skin microbiome of vertebrates. MICROBIOME 2019; 7:79. [PMID: 31122279 PMCID: PMC6533770 DOI: 10.1186/s40168-019-0694-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/08/2019] [Indexed: 05/05/2023]
Abstract
The skin constitutes the primary physical barrier between vertebrates and their external environment. Characterization of skin microorganisms is essential for understanding how a host evolves in association with its microbial symbionts, modeling immune system development, diagnosing illnesses, and exploring the origins of potential zoonoses that affect humans. Although many studies have characterized the human microbiome with culture-independent techniques, far less is known about the skin microbiome of other mammals, amphibians, birds, fish, and reptiles. The aim of this review is to summarize studies that have leveraged high-throughput sequencing to better understand the skin microorganisms that associate with members of classes within the subphylum Vertebrata. Specifically, links will be explored between the skin microbiome and vertebrate characteristics, including geographic location, biological sex, animal interactions, diet, captivity, maternal transfer, and disease. Recent literature on parallel patterns between host evolutionary history and their skin microbial communities, or phylosymbiosis, will also be analyzed. These factors must be considered when designing future microbiome studies to ensure that the conclusions drawn from basic research translate into useful applications, such as probiotics and successful conservation strategies for endangered and threatened animals.
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Affiliation(s)
- Ashley A Ross
- University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
- Present address: Ontario Veterinary College, University of Guelph, 419 Gordon St, Guelph, Ontario, N1G 2W1, Canada
| | - Aline Rodrigues Hoffmann
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 660 Raymond Stotzer Pkwy, College Station, TX, USA
| | - Josh D Neufeld
- University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
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99
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Teper D, Zhang Y, Wang N. TfmR, a novel TetR-family transcriptional regulator, modulates the virulence of Xanthomonas citri in response to fatty acids. MOLECULAR PLANT PATHOLOGY 2019; 20:701-715. [PMID: 30919570 PMCID: PMC6637906 DOI: 10.1111/mpp.12786] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The type III secretion system (T3SS) is required for Xanthomonas citri subsp. citri (Xcc) virulence by translocating effectors into host cytoplasm to promote disease development. The T3SS is controlled by the master transcriptional regulators HrpG and HrpX. While the function of HrpG and HrpX are well characterized, their upstream regulation remains elusive. By using transposon mutagenesis, we identified XAC3052, a TetR-family transcriptional regulator, which regulates T3SS gene expression. Deletion of XAC3052 caused significant reduction in the expression of T3SS and effector genes in vitro and in planta; as well as reduction of virulence in sweet orange (Citrus sinensis). Overexpression of hrpG restored the virulence of ∆XAC3052, suggesting that the loss of virulence is caused by reduction of T3SS gene expression. XAC3052 directly binds to the promoter region and represses the transcription of fadE, mhpC and fadH genes. FadE, MhpC and FadH are not involved in T3SS regulation, but involved in fatty acid catabolism. ∆XAC3052 displays altered fatty acid composition and retarded growth in environments limited in fatty acids. Exogenously supplemented long-chain fatty acids activate the fadE/mhpC promoter and suppress T3SS promoters in wild-type Xac but not in ∆XAC3052. Moreover, the binding of XAC3052 to its target promoter was disrupted by long-chain fatty acids in vitro. Herein, XAC3052 is designated as TfmR (T3SS and Fatty acid Mechanism Regulator). This study identifies a novel regulator of fatty acid metabolism and suggests that fatty acids play an important role in the metabolic control of virulence in Xcc.
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Affiliation(s)
- Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
| | - Yanan Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
- China-USA Citrus Huanglongbing Joint Laboratory (A joint laboratory of The University of Florida’s Institute of Food and Agricultural Sciences and Gannan Normal University), National Navel Orange Engineering Research CenterGannan Normal UniversityGanzhou341000JiangxiChina
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Pulkkinen K, Pekkala N, Ashrafi R, Hämäläinen DM, Nkembeng AN, Lipponen A, Hiltunen T, Valkonen JK, Taskinen J. Effect of resource availability on evolution of virulence and competition in an environmentally transmitted pathogen. FEMS Microbiol Ecol 2019; 94:4962392. [PMID: 29659817 DOI: 10.1093/femsec/fiy060] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 04/04/2018] [Indexed: 01/21/2023] Open
Abstract
Understanding ecological and epidemiological factors driving pathogen evolution in contemporary time scales is a major challenge in modern health management. Pathogens that replicate outside the hosts are subject to selection imposed by ambient environmental conditions. Increased nutrient levels could increase pathogen virulence by pre-adapting for efficient use of resources upon contact to a nutrient rich host or by favouring transmission of fast-growing virulent strains. We measured changes in virulence and competition in Flavobacterium columnare, a bacterial pathogen of freshwater fish, under high and low nutrient levels. To test competition between strains in genotype mixtures, we developed a quantitative real-time PCR assay. We found that a virulent strain maintained its virulence and outcompeted less virulent strains independent of the nutrient level and resource renewal rate while a less virulent strain further lost virulence in chemostats under low nutrient level and over long-term serial culture under high nutrient level. Our results suggest that increased outside-host nutrient levels might maintain virulence in less virulent strains and increase their contribution to epidemics in aquaculture. The results highlight a need to further explore the role of resource in the outside-host environment in maintaining strain diversity and driving evolution of virulence among environmentally growing pathogens.
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Affiliation(s)
- Katja Pulkkinen
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
| | - Nina Pekkala
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
| | - Roghaieh Ashrafi
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland.,Centre of Excellence in Biological Interactions, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä,Finland
| | - Dorrit M Hämäläinen
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
| | - Aloysius N Nkembeng
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
| | - Anssi Lipponen
- A. I. Virtanen Institute for Molecular Sciences, P. O. Box 1627, (Neulaniementie 2), University of Eastern Finland, Kuopio, Finland
| | - Teppo Hiltunen
- Department of Microbiology, P. O. Box 56, (Viikinkaari 9), University of Helsinki, Helsinki, Finland
| | - Janne K Valkonen
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland.,Centre of Excellence in Biological Interactions, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä,Finland
| | - Jouni Taskinen
- Department of Biological and Environmental Science, P. O. Box 35, (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
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