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Jackson M, Vineberg S, Theis KR. The Epistemology of Bacterial Virulence Factor Characterization. Microorganisms 2024; 12:1272. [PMID: 39065041 PMCID: PMC11278562 DOI: 10.3390/microorganisms12071272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 07/28/2024] Open
Abstract
The field of microbial pathogenesis seeks to identify the agents and mechanisms responsible for disease causation. Since Robert Koch introduced postulates that were used to guide the characterization of microbial pathogens, technological advances have substantially increased the capacity to rapidly identify a causative infectious agent. Research efforts currently focus on causation at the molecular level with a search for virulence factors (VFs) that contribute to different stages of the infectious process. We note that the quest to identify and characterize VFs sometimes lacks scientific rigor, and this suggests a need to examine the epistemology of VF characterization. We took this premise as an opportunity to explore the epistemology of VF characterization. In this perspective, we discuss how the characterization of various gene products that evolved to facilitate bacterial survival in the broader environment have potentially been prematurely mischaracterized as VFs that contribute to pathogenesis in the context of human biology. Examples of the reasoning that can affect misinterpretation, or at least a premature assignment of mechanistic causation, are provided. Our aim is to refine the categorization of VFs by emphasizing a broader biological view of their origin.
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Affiliation(s)
- Matthew Jackson
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Susan Vineberg
- Department of Philosophy, Wayne State University, Detroit, MI 48201, USA;
| | - Kevin R. Theis
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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2
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Foxall RL, Means J, Marcinkiewicz AL, Schillaci C, DeRosia-Banick K, Xu F, Hall JA, Jones SH, Cooper VS, Whistler CA. Inoviridae prophage and bacterial host dynamics during diversification, succession, and Atlantic invasion of Pacific-native Vibrio parahaemolyticus. mBio 2024; 15:e0285123. [PMID: 38112441 PMCID: PMC10790759 DOI: 10.1128/mbio.02851-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 11/08/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE An understanding of the processes that contribute to the emergence of pathogens from environmental reservoirs is critical as changing climate precipitates pathogen evolution and population expansion. Phylogeographic analysis of Vibrio parahaemolyticus hosts combined with the analysis of their Inoviridae phage resolved ambiguities of diversification dynamics which preceded successful Atlantic invasion by the epidemiologically predominant ST36 lineage. It has been established experimentally that filamentous phage can limit host recombination, but here, we show that phage loss is linked to rapid bacterial host diversification during epidemic spread in natural ecosystems alluding to a potential role for ubiquitous inoviruses in the adaptability of pathogens. This work paves the way for functional analyses to define the contribution of inoviruses in the evolutionary dynamics of environmentally transmitted pathogens.
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Affiliation(s)
- Randi L. Foxall
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Jillian Means
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Graduate Program in Microbiology, University of New Hampshire, Durham, New Hampshire, USA
| | - Ashely L. Marcinkiewicz
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Graduate Program in Microbiology, University of New Hampshire, Durham, New Hampshire, USA
| | - Christopher Schillaci
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, USA
| | - Kristin DeRosia-Banick
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
| | - Feng Xu
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Jeffrey A. Hall
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Hubbard Center for Genome Studies, University of New Hampshire, Durham, New Hampshire, USA
| | - Stephen H. Jones
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, USA
| | - Vaughn S. Cooper
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Cheryl A. Whistler
- Northeast Center for Vibrio Disease and Ecology, University of New Hampshire, Durham, New Hampshire, USA
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
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Zhao J, Nair S, Zhang Z, Wang Z, Jiao N, Zhang Y. Macroalgal virosphere assists with host-microbiome equilibrium regulation and affects prokaryotes in surrounding marine environments. THE ISME JOURNAL 2024; 18:wrae083. [PMID: 38709876 PMCID: PMC11126160 DOI: 10.1093/ismejo/wrae083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/23/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024]
Abstract
The microbiomes in macroalgal holobionts play vital roles in regulating macroalgal growth and ocean carbon cycling. However, the virospheres in macroalgal holobionts remain largely underexplored, representing a critical knowledge gap. Here we unveil that the holobiont of kelp (Saccharina japonica) harbors highly specific and unique epiphytic/endophytic viral species, with novelty (99.7% unknown) surpassing even extreme marine habitats (e.g. deep-sea and hadal zones), indicating that macroalgal virospheres, despite being closest to us, are among the least understood. These viruses potentially maintain microbiome equilibrium critical for kelp health via lytic-lysogenic infections and the expression of folate biosynthesis genes. In-situ kelp mesocosm cultivation and metagenomic mining revealed that kelp holobiont profoundly reshaped surrounding seawater and sediment virus-prokaryote pairings through changing surrounding environmental conditions and virus-host migrations. Some kelp epiphytic viruses could even infect sediment autochthonous bacteria after deposition. Moreover, the presence of ample viral auxiliary metabolic genes for kelp polysaccharide (e.g. laminarin) degradation underscores the underappreciated viral metabolic influence on macroalgal carbon cycling. This study provides key insights into understanding the previously overlooked ecological significance of viruses within macroalgal holobionts and the macroalgae-prokaryotes-virus tripartite relationship.
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Affiliation(s)
- Jiulong Zhao
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Shailesh Nair
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Zenghu Zhang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zengmeng Wang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Nianzhi Jiao
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
| | - Yongyu Zhang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, Shandong, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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4
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Ekdahl LI, Salcedo JA, Dungan MM, Mason DV, Myagmarsuren D, Murphy HA. Selection on plastic adherence leads to hyper-multicellular strains and incidental virulence in the budding yeast. eLife 2023; 12:e81056. [PMID: 37916911 PMCID: PMC10764007 DOI: 10.7554/elife.81056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/01/2023] [Indexed: 11/03/2023] Open
Abstract
Many disease-causing microbes are not obligate pathogens; rather, they are environmental microbes taking advantage of an ecological opportunity. The existence of microbes whose life cycle does not require a host and are not normally pathogenic, yet are well-suited to host exploitation, is an evolutionary puzzle. One hypothesis posits that selection in the environment may favor traits that incidentally lead to pathogenicity and virulence, or serve as pre-adaptations for survival in a host. An example of such a trait is surface adherence. To experimentally test the idea of 'accidental virulence', replicate populations of Saccharomyces cerevisiae were evolved to attach to a plastic bead for hundreds of generations. Along with plastic adherence, two multicellular phenotypes- biofilm formation and flor formation- increased; another phenotype, pseudohyphal growth, responded to the nutrient limitation. Thus, experimental selection led to the evolution of highly-adherent, hyper-multicellular strains. Wax moth larvae injected with evolved hyper-multicellular strains were significantly more likely to die than those injected with evolved non-multicellular strains. Hence, selection on plastic adherence incidentally led to the evolution of enhanced multicellularity and increased virulence. Our results support the idea that selection for a trait beneficial in the open environment can inadvertently generate opportunistic, 'accidental' pathogens.
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Affiliation(s)
- Luke I Ekdahl
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Juliana A Salcedo
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Matthew M Dungan
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Despina V Mason
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | | | - Helen A Murphy
- Department of Biology, College of William and MaryWilliamsburgUnited States
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Bulannga RB, Schmidt S. Two Predators, One Prey - the Interaction Between Bacteriophage, Bacterivorous Ciliates, and Escherichia coli. MICROBIAL ECOLOGY 2023; 86:1620-1631. [PMID: 36723682 DOI: 10.1007/s00248-022-02163-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Bacterivorous ciliates and lytic bacteriophages are two major predators in aquatic environments, competing for the same type of prey. This study investigated the possible interaction of these different microorganisms and their influence on the activity of each other. Therefore, two bacterivorous ciliates, Paramecium sp. RB1 and Tetrahymena sp. RB2, were used as representative ciliates; a T4-like Escherichia coli targeting lytic bacteriophage as a model virus; and E. coli ATCC 25922 as a susceptible bacterial host and prey. The growth of the two ciliates with E. coli ATCC 25922 as prey was affected by the presence of phage particles. The grazing activity of the two ciliates resulted in more than a 99% reduction of the phage titer and bacterial cell numbers. However, viable phage particles were recovered from individual washed cells of the two ciliates after membrane filtration. Therefore, ciliates such as Paramecium sp. RB1 and Tetrahymena sp. RB2 can remove bacteriophages present in natural and artificial waters by ingesting the viral particles and eliminating bacterial host cells required for viral replication. The ingestion of phage particles may marginally contribute to the nutrient supply of the ciliates. However, the interaction of phage particles with ciliate cells may contribute to the transmission of bacteriophages in aquatic environments.
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Affiliation(s)
- Rendani Bridghette Bulannga
- Discipline of Microbiology, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, 3209, South Africa
| | - Stefan Schmidt
- Discipline of Microbiology, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, 3209, South Africa.
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Brüssow H. The human microbiome project at ten years - some critical comments and reflections on "our third genome", the human virome. MICROBIOME RESEARCH REPORTS 2023; 2:7. [PMID: 38045612 PMCID: PMC10688805 DOI: 10.20517/mrr.2022.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/02/2023] [Accepted: 03/21/2023] [Indexed: 12/05/2023]
Abstract
The Human Microbiome Project (HMP) has raised great expectations claiming the far-reaching influence of the microbiome on human health and disease ranging from obesity and malnutrition to effects going well beyond the gut. So far, with the notable exception of fecal microbiota transplantation in Clostridioides difficile infection, practical application of microbiome intervention has only achieved modest clinical effects. It is argued here that we need criteria for the link between microbiome and disease modelled on the links between pathogens and infectious disease in Koch's postulates. The most important question is whether the microbiome change is a cause of the given disease or a consequence of a pathology leading to disease where the microbiome change is only a parallel event without a causal connection to the disease - in philosophical parlance, an epiphenomenon. Also discussed here is whether human virome research is a necessary complement to the microbiome project with a high potential for practical applications.
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Affiliation(s)
- Harald Brüssow
- KU Leuven, Department of Biosystems, Laboratory of Gene Technology, Leuven B-3001, Belgium
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7
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Rayamajhee B, Willcox MDP, Henriquez FL, Petsoglou C, Subedi D, Carnt N. Acanthamoeba, an environmental phagocyte enhancing survival and transmission of human pathogens. Trends Parasitol 2022; 38:975-990. [PMID: 36109313 DOI: 10.1016/j.pt.2022.08.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 01/13/2023]
Abstract
The opportunistic protist Acanthamoeba, which interacts with other microbes such as bacteria, fungi, and viruses, shows significant similarity in cellular and functional aspects to human macrophages. Intracellular survival of microbes in this microbivorous amoebal host may be a crucial step for initiation of infection in higher eukaryotic cells. Therefore, Acanthamoeba-microbe adaptations are considered an evolutionary model of macrophage-pathogen interactions. This paper reviews Acanthamoeba as an emerging human pathogen and different ecological interactions between Acanthamoeba and microbes that may serve as environmental training grounds and a genetic melting pot for the evolution, persistence, and transmission of potential human pathogens.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Mark D P Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Fiona L Henriquez
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, Blantyre, South Lanarkshire, G72 0LH, UK
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, Southeastern Sydney Local Health District, Sydney, Australia; Save Sight Institute, University of Sydney, Sydney, Australia
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia
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8
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Soto W. Emerging Research Topics in the Vibrionaceae and the Squid- Vibrio Symbiosis. Microorganisms 2022; 10:microorganisms10101946. [PMID: 36296224 PMCID: PMC9607633 DOI: 10.3390/microorganisms10101946] [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: 08/28/2022] [Revised: 09/22/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022] Open
Abstract
The Vibrionaceae encompasses a cosmopolitan group that is mostly aquatic and possesses tremendous metabolic and genetic diversity. Given the importance of this taxon, it deserves continued and deeper research in a multitude of areas. This review outlines emerging topics of interest within the Vibrionaceae. Moreover, previously understudied research areas are highlighted that merit further exploration, including affiliations with marine plants (seagrasses), microbial predators, intracellular niches, and resistance to heavy metal toxicity. Agarases, phototrophy, phage shock protein response, and microbial experimental evolution are also fields discussed. The squid-Vibrio symbiosis is a stellar model system, which can be a useful guiding light on deeper expeditions and voyages traversing these "seas of interest". Where appropriate, the squid-Vibrio mutualism is mentioned in how it has or could facilitate the illumination of these various subjects. Additional research is warranted on the topics specified herein, since they have critical relevance for biomedical science, pharmaceuticals, and health care. There are also practical applications in agriculture, zymology, food science, and culinary use. The tractability of microbial experimental evolution is explained. Examples are given of how microbial selection studies can be used to examine the roles of chance, contingency, and determinism (natural selection) in shaping Earth's natural history.
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Affiliation(s)
- William Soto
- Integrated Science Center Rm 3035, Department of Biology, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA
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Rayamajhee B, Sharma S, Willcox M, Henriquez FL, Rajagopal RN, Shrestha GS, Subedi D, Bagga B, Carnt N. Assessment of genotypes, endosymbionts and clinical characteristics of Acanthamoeba recovered from ocular infection. BMC Infect Dis 2022; 22:757. [PMID: 36175838 PMCID: PMC9520893 DOI: 10.1186/s12879-022-07741-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/12/2022] [Indexed: 11/22/2022] Open
Abstract
Introduction Acanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis, a sight-threatening, painful and difficult to treat corneal infection which is often reported among contact lens wearers and patients with ocular trauma. Acanthamoeba comprises over 24 species and currently 23 genotypes (T1-T23) have been identified. Aims This retrospective study was designed to examine the Acanthamoeba species and genotypes recovered from patients with Acanthamoeba keratitis (AK), determine the presence of endosymbionts in ocular isolates of Acanthamoeba and review the clinical presentations. Methodology Thirteen culture-confirmed AK patients treated in a tertiary eye care facility in Hyderabad, India from February to October 2020 were included in this study. The clinical manifestations, medications and visual outcomes of all patients were obtained from medical records. The Acanthamoeba isolates were identified by sequencing the ribosomal nuclear subunit (rns) gene. Acanthamoeba isolates were assessed for the presence of bacterial or fungal endosymbionts using molecular assays, PCR and fluorescence in situ hybridization (FISH). Results The mean age of the patients was 33 years (SD ± 17.4; 95% CI 22.5 to 43.5 years). Six (46.2%) cases had AK associated risk factors; four patients had ocular trauma and two were contact lens wearers. A. culbertsoni (6/13, 46.2%) was the most common species, followed by A. polyphaga and A. triangularis. Most of the isolates (12/13) belonged to genotype T4 and one was a T12; three sub-clusters T4A, T4B, and T4F were identified within the T4 genotype. There was no significant association between Acanthamoeba types and clinical outcomes. Eight (61.5%) isolates harboured intracellular bacteria and one contained Malassezia restricta. The presence of intracellular microbes was associated with a higher proportion of stromal infiltrates (88.9%, 8/9), epithelial defect (55.6%, 5/9) and hypopyon (55.6%, 5/9) compared to 50% (2/4), 25% (1/4) and 25% (1/4) AK cases without intracellular microbes, respectively. Conclusions Genotype T4 was the predominant isolate in southern India. This is the second report of T12 genotype identified from AK patient in India, which is rarely reported worldwide. The majority of the Acanthamoeba clinical isolates in this study harboured intracellular microbes, which may impact clinical characteristics of AK. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07741-4.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia.
| | - Savitri Sharma
- Jhaveri Microbiology Centre, Prof. Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L. V. Prasad Eye Institute (LVPEI), Kallam Anji Reddy Campus, Hyderabad, India
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Fiona L Henriquez
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland (UWS), Paisley, PA1 2BE, Scotland, UK
| | | | - Gauri Shankar Shrestha
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Bhupesh Bagga
- The Cornea Institute, L V Prasad Eye Institute, Banjara Hills, Hyderabad, India
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
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10
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DuBose JG, Robeson MS, Hoogshagen M, Olsen H, Haselkorn TS. Complexities of Inferring Symbiont Function: Paraburkholderia Symbiont Dynamics in Social Amoeba Populations and Their Impacts on the Amoeba Microbiota. Appl Environ Microbiol 2022; 88:e0128522. [PMID: 36043858 PMCID: PMC9499018 DOI: 10.1128/aem.01285-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 08/11/2022] [Indexed: 11/20/2022] Open
Abstract
The relationship between the social amoeba Dictyostelium discoideum and its endosymbiotic bacteria Paraburkholderia provides a model system for studying the development of symbiotic relationships. Laboratory experiments have shown that any of three species of the Paraburkholderia symbiont allow D. discoideum food bacteria to persist through the amoeba life cycle and survive in amoeba spores rather than being fully digested. This phenomenon is termed "farming," as it potentially allows spores dispersed to food-poor locations to grow their own. The occurrence and impact of farming in natural populations, however, have been a challenge to measure. Here, we surveyed natural D. discoideum populations and found that only one of the three symbiont species, Paraburkholderia agricolaris, remained prevalent. We then explored the effect of Paraburkholderia on the amoeba microbiota, expecting that by facilitating bacterial food carriage, it would diversify the microbiota. Contrary to our expectations, Paraburkholderia tended to infectiously dominate the D. discoideum microbiota, in some cases decreasing diversity. Similarly, we found little evidence for Paraburkholderia facilitating the carriage of particular food bacteria. These findings highlight the complexities of inferring symbiont function in nature and suggest the possibility that Paraburkholderia could be playing multiple roles for its host. IMPORTANCE The functions of symbionts in natural populations can be difficult to completely discern. The three Paraburkholderia bacterial farming symbionts of the social amoeba Dictyostelium discoideum have been shown in the laboratory environment to allow the amoebas to carry, rather than fully digest, food bacteria. This potentially provides a fitness benefit to the amoebas upon dispersal to food-poor environments, as they could grow their food. We expected that meaningful food carriage would manifest as a more diverse microbiota. Surprisingly, we found that Paraburkholderia tended to infectiously dominate the D. discoideum microbiota rather than diversifying it. We determined that only one of the three Paraburkholderia symbionts has increased in prevalence in natural populations in the past 20 years, suggesting that this symbiont may be beneficial, however. These findings suggest that Paraburkholderia may have an alternative function for its host, which drives its prevalence in natural populations.
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Affiliation(s)
- James G. DuBose
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
| | - Michael S. Robeson
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | | | - Hunter Olsen
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
| | - Tamara S. Haselkorn
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
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11
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Aylward FO, Moniruzzaman M. Viral Complexity. Biomolecules 2022; 12:1061. [PMID: 36008955 PMCID: PMC9405923 DOI: 10.3390/biom12081061] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 12/18/2022] Open
Abstract
Although traditionally viewed as streamlined and simple, discoveries over the last century have revealed that viruses can exhibit surprisingly complex physical structures, genomic organization, ecological interactions, and evolutionary histories. Viruses can have physical dimensions and genome lengths that exceed many cellular lineages, and their infection strategies can involve a remarkable level of physiological remodeling of their host cells. Virus-virus communication and widespread forms of hyperparasitism have been shown to be common in the virosphere, demonstrating that dynamic ecological interactions often shape their success. And the evolutionary histories of viruses are often fraught with complexities, with chimeric genomes including genes derived from numerous distinct sources or evolved de novo. Here we will discuss many aspects of this viral complexity, with particular emphasis on large DNA viruses, and provide an outlook for future research.
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Affiliation(s)
- Frank O. Aylward
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
- Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mohammad Moniruzzaman
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Coral Gables, FL 33149, USA;
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12
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Hoque MM, Noorian P, Espinoza-Vergara G, Manuneedhi Cholan P, Kim M, Rahman MH, Labbate M, Rice SA, Pernice M, Oehlers SH, McDougald D. Adaptation to an amoeba host drives selection of virulence-associated traits in Vibrio cholerae. THE ISME JOURNAL 2022; 16:856-867. [PMID: 34654895 PMCID: PMC8857207 DOI: 10.1038/s41396-021-01134-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/20/2021] [Accepted: 09/29/2021] [Indexed: 12/02/2022]
Abstract
Predation by heterotrophic protists drives the emergence of adaptive traits in bacteria, and often these traits lead to altered interactions with hosts and persistence in the environment. Here we studied adaptation of the cholera pathogen, Vibrio cholerae during long-term co-incubation with the protist host, Acanthamoeba castellanii. We determined phenotypic and genotypic changes associated with long-term intra-amoebal host adaptation and how this impacts pathogen survival and fitness. We showed that adaptation to the amoeba host leads to temporal changes in multiple phenotypic traits in V. cholerae that facilitate increased survival and competitive fitness in amoeba. Genome sequencing and mutational analysis revealed that these altered lifestyles were linked to non-synonymous mutations in conserved regions of the flagellar transcriptional regulator, flrA. Additionally, the mutations resulted in enhanced colonisation in zebrafish, establishing a link between adaptation of V. cholerae to amoeba predation and enhanced environmental persistence. Our results show that pressure imposed by amoeba on V. cholerae selects for flrA mutations that serves as a key driver for adaptation. Importantly, this study provides evidence that adaptive traits that evolve in pathogens in response to environmental predatory pressure impact the colonisation of eukaryotic organisms by these pathogens.
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Affiliation(s)
- M. Mozammel Hoque
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Parisa Noorian
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Gustavo Espinoza-Vergara
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Pradeep Manuneedhi Cholan
- grid.1013.30000 0004 1936 834XTuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health & Marie Bashir Institute, The University of Sydney, Camperdown, NSW Australia
| | - Mikael Kim
- grid.117476.20000 0004 1936 7611Climate Change Cluster, University of Technology Sydney, Sydney, NSW Australia
| | - Md Hafizur Rahman
- grid.117476.20000 0004 1936 7611School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW Australia
| | - Maurizio Labbate
- grid.117476.20000 0004 1936 7611School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW Australia
| | - Scott A. Rice
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia ,grid.59025.3b0000 0001 2224 0361Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Mathieu Pernice
- grid.117476.20000 0004 1936 7611Climate Change Cluster, University of Technology Sydney, Sydney, NSW Australia
| | - Stefan H. Oehlers
- grid.1013.30000 0004 1936 834XTuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health & Marie Bashir Institute, The University of Sydney, Camperdown, NSW Australia
| | - Diane McDougald
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia ,grid.59025.3b0000 0001 2224 0361Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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13
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Alomari MMM, Dec M, Urban-Chmiel R. Bacteriophages as an Alternative Method for Control of Zoonotic and Foodborne Pathogens. Viruses 2021; 13:2348. [PMID: 34960617 PMCID: PMC8709489 DOI: 10.3390/v13122348] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/11/2022] Open
Abstract
The global increase in multidrug-resistant infections caused by various pathogens has raised concerns in human and veterinary medicine. This has renewed interest in the development of alternative methods to antibiotics, including the use of bacteriophages for controlling bacterial infections. The aim of this review is to present potential uses of bacteriophages as an alternative to antibiotics in the control of bacterial infections caused by multidrug-resistant bacteria posing a risk to humans, with particular emphasis on foodborne and zoonotic pathogens. A varied therapeutic and immunomodulatory (activation or suppression) effect of bacteriophages on humoral and cellular immune response mechanisms has been demonstrated. The antibiotic resistance crisis caused by global antimicrobial resistance among bacteria creates a compelling need for alternative safe and selectively effective antibacterial agents. Bacteriophages have many properties indicating their potential suitability as therapeutic and/or prophylactic agents. In many cases, bacteriophages can also be used in food quality control against microorganisms such as Salmonella, Escherichia coli, Listeria, Campylobacter and others. Future research will provide potential alternative solutions using bacteriophages to treat infections caused by multidrug-resistant bacteria.
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Affiliation(s)
| | - Marta Dec
- Department of Veterinary Prevention and Avian Diseases, Faculty of Veterinary Medicine University of Life Sciences in Lublin, 20-033 Lublin, Poland;
| | - Renata Urban-Chmiel
- Department of Veterinary Prevention and Avian Diseases, Faculty of Veterinary Medicine University of Life Sciences in Lublin, 20-033 Lublin, Poland;
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14
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Jasinski-Bergner S, Mandelboim O, Seliger B. Molecular mechanisms of human herpes viruses inferring with host immune surveillance. J Immunother Cancer 2021; 8:jitc-2020-000841. [PMID: 32616556 PMCID: PMC7333871 DOI: 10.1136/jitc-2020-000841] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2020] [Indexed: 02/06/2023] Open
Abstract
Several human herpes viruses (HHVs) exert oncogenic potential leading to malignant transformation of infected cells and/or tissues. The molecular processes induced by viral-encoded molecules including microRNAs, peptides, and proteins contributing to immune evasion of the infected host cells are equal to the molecular processes of immune evasion mediated by tumor cells independently of viral infections. Such major immune evasion strategies include (1) the downregulation of proinflammatory cytokines/chemokines as well as the induction of anti-inflammatory cytokines/chemokines, (2) the downregulation of major histocompatibility complex (MHC) class Ia directly as well as indirectly by downregulation of the components involved in the antigen processing, and (3) the downregulation of stress-induced ligands for activating receptors on immune effector cells with NKG2D leading the way. Furthermore, (4) immune modulatory molecules like MHC class Ib molecules and programmed cell death1 ligand 1 can be upregulated on infections with certain herpes viruses. This review article focuses on the known molecular mechanisms of HHVs modulating the above-mentioned possibilities for immune surveillance and even postulates a temporal order linking regular tumor immunology with basic virology and offering putatively novel insights for targeting HHVs.
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Affiliation(s)
- Simon Jasinski-Bergner
- Institute for Medical Immunology, Martin-Luther-Universitat Halle-Wittenberg, Halle (Saale), Germany
| | - Ofer Mandelboim
- Immunology & Cancer Research Center, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Barbara Seliger
- Institute for Medical Immunology, Martin-Luther-Universitat Halle-Wittenberg, Halle (Saale), Germany
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15
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Radosa S, Sprague JL, Lau SH, Tóth R, Linde J, Krüger T, Sprenger M, Kasper L, Westermann M, Kniemeyer O, Hube B, Brakhage AA, Gácser A, Hillmann F. The fungivorous amoeba Protostelium aurantium targets redox homeostasis and cell wall integrity during intracellular killing of Candida parapsilosis. Cell Microbiol 2021; 23:e13389. [PMID: 34460149 DOI: 10.1111/cmi.13389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 03/08/2021] [Accepted: 08/26/2021] [Indexed: 12/13/2022]
Abstract
Predatory interactions among microbes are major evolutionary driving forces for biodiversity. The fungivorous amoeba Protostelium aurantium has a wide fungal food spectrum including foremost pathogenic members of the genus Candida. Here we show that upon phagocytic ingestion by the amoeba, Candida parapsilosis is confronted with an oxidative burst and undergoes lysis within minutes of processing in acidified phagolysosomes. On the fungal side, a functional genomic approach identified copper and redox homeostasis as primary targets of amoeba predation, with the highly expressed copper exporter gene CRP1 and the peroxiredoxin gene PRX1 contributing to survival when encountered with P. aurantium. The fungicidal activity was largely retained in intracellular vesicles of the amoebae. Following their isolation, the content of these vesicles induced immediate killing and lysis of C. parapsilosis in vitro. Proteomic analysis identified 56 vesicular proteins from P. aurantium. Although completely unknown proteins were dominant, many of them could be categorised as hydrolytic enzymes targeting the fungal cell wall, indicating that fungal cell wall structures are under selection pressure by predatory phagocytes in natural environments. TAKE AWAY: The amoeba Protostelium aurantium feeds on fungi, such as Candida parapsilosis. Ingested yeast cells are exposed to reactive oxygen species. A copper exporter and a peroxiredoxin contribute to fungal defence. Yeast cells undergo intracellular lysis. Lysis occurs via a cocktail of hydrolytic enzymes from intracellular vesicles.
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Affiliation(s)
- Silvia Radosa
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Jakob L Sprague
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.,Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Siu-Hin Lau
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Renáta Tóth
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Jörg Linde
- Research Group Systems Biology and Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Thomas Krüger
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Marcel Sprenger
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.,Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | | | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Bernhard Hube
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.,Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Axel A Brakhage
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.,Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
| | - Attila Gácser
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Falk Hillmann
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany
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16
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Silveira CB, Luque A, Rohwer F. The landscape of lysogeny across microbial community density, diversity and energetics. Environ Microbiol 2021; 23:4098-4111. [PMID: 34121301 DOI: 10.1111/1462-2920.15640] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 12/11/2022]
Abstract
Lysogens are common at high bacterial densities, an observation that contrasts with the prevailing view of lysogeny as a low-density refugium strategy. Here, we review the mechanisms regulating lysogeny in complex communities and show that the additive effects of coinfections, diversity and host energic status yield a bimodal distribution of lysogeny as a function of microbial densities. At high cell densities (above 106 cells ml-1 or g-1 ) and low diversity, coinfections by two or more phages are frequent and excess energy availability stimulates inefficient metabolism. Both mechanisms favour phage integration and characterize the Piggyback-the-Winner dynamic. At low densities (below 105 cells ml-1 or g-1 ), starvation represses lytic genes and extends the time window for lysogenic commitment, resulting in a higher frequency of coinfections that cause integration. This pattern follows the predictions of the refugium hypothesis. At intermediary densities (between 105 and 106 cells ml-1 or g-1 ), encounter rates and efficient energy metabolism favour lysis. This may involve Kill-the-Winner lytic dynamics and induction. Based on these three regimes, we propose a framework wherein phage integration occurs more frequently at both ends of the host density gradient, with distinct underlying molecular mechanisms (coinfections and host metabolism) dominating at each extreme.
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Affiliation(s)
- Cynthia B Silveira
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL, 33143, USA.,Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Causeway, Miami, FL, 33149, USA
| | - Antoni Luque
- Viral Information Institute, San Diego State University, 5500 Campanile Dr., San Diego, CA, 92182, USA.,Department of Mathematics and Statistics, San Diego State University, 5500 Campanile Dr., San Diego, CA, 92182, USA.,Computational Science Research Center, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Forest Rohwer
- Viral Information Institute, San Diego State University, 5500 Campanile Dr., San Diego, CA, 92182, USA.,Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
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17
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Forcone K, Coutinho FH, Cavalcanti GS, Silveira CB. Prophage Genomics and Ecology in the Family Rhodobacteraceae. Microorganisms 2021; 9:microorganisms9061115. [PMID: 34064105 PMCID: PMC8224337 DOI: 10.3390/microorganisms9061115] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 12/20/2022] Open
Abstract
Roseobacters are globally abundant bacteria with critical roles in carbon and sulfur biogeochemical cycling. Here, we identified 173 new putative prophages in 79 genomes of Rhodobacteraceae. These prophages represented 1.3 ± 0.15% of the bacterial genomes and had no to low homology with reference and metagenome-assembled viral genomes from aquatic and terrestrial ecosystems. Among the newly identified putative prophages, 35% encoded auxiliary metabolic genes (AMGs), mostly involved in secondary metabolism, amino acid metabolism, and cofactor and vitamin production. The analysis of integration sites and gene homology showed that 22 of the putative prophages were actually gene transfer agents (GTAs) similar to a GTA of Rhodobacter capsulatus. Twenty-three percent of the predicted prophages were observed in the TARA Oceans viromes generated from free viral particles, suggesting that they represent active prophages capable of induction. The distribution of these prophages was significantly associated with latitude and temperature. The prophages most abundant at high latitudes encoded acpP, an auxiliary metabolic gene involved in lipid synthesis and membrane fluidity at low temperatures. Our results show that prophages and gene transfer agents are significant sources of genomic diversity in roseobacter, with potential roles in the ecology of this globally distributed bacterial group.
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Affiliation(s)
- Kathryn Forcone
- Department of Biology, University of Miami, 1301 Memorial Dr., Coral Gables, Miami, FL 33146, USA; (K.F.); (G.S.C.)
| | - Felipe H. Coutinho
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández de Elche, Aptdo. 18, Ctra. Alicante-Valencia, s/n, 03550 San Juan de Alicante, Spain;
| | - Giselle S. Cavalcanti
- Department of Biology, University of Miami, 1301 Memorial Dr., Coral Gables, Miami, FL 33146, USA; (K.F.); (G.S.C.)
| | - Cynthia B. Silveira
- Department of Biology, University of Miami, 1301 Memorial Dr., Coral Gables, Miami, FL 33146, USA; (K.F.); (G.S.C.)
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
- Correspondence:
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18
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Revisiting marine lytic and lysogenic virus-host interactions: Kill-the-Winner and Piggyback-the-Winner. Sci Bull (Beijing) 2021; 66:871-874. [PMID: 36654234 DOI: 10.1016/j.scib.2020.12.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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19
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Loh B, Chen J, Manohar P, Yu Y, Hua X, Leptihn S. A Biological Inventory of Prophages in A. baumannii Genomes Reveal Distinct Distributions in Classes, Length, and Genomic Positions. Front Microbiol 2020; 11:579802. [PMID: 33343523 PMCID: PMC7744312 DOI: 10.3389/fmicb.2020.579802] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/10/2020] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii is of major clinical importance as the bacterial pathogen often causes hospital acquired infections, further complicated by the high prevalence of antibiotic resistant strains. Aside from natural tolerance to certain antibiotic classes, resistance is often acquired by the exchange of genetic information via conjugation but also by the high natural competence exhibited by A. baumannii. In addition, bacteriophages are able to introduce resistance genes but also toxins and virulence factors via phage mediated transduction. In this work, we analyzed the complete genomes of 177 A. baumannii strains for the occurrence of prophages, and analyzed their taxonomy, size and positions of insertion. Among all the prophages that were detected, Siphoviridae and Myoviridae were the two most commonly found families, while the average genome size was determined to be approximately 4 Mbp. Our data shows the wide variation in the number of prophages in A. baumannii genomes and the prevalence of certain prophages within strains that are most "successful" or potentially beneficial to the host. Our study also revealed that only two specific sites of insertion within the genome of the host bacterium are being used, with few exceptions only. Lastly, we analyzed the existence of genes that are encoded in the prophages, which may confer antimicrobial resistance (AMR). Several phages carry AMR genes, including OXA-23 and NDM-1, illustrating the importance of lysogenic phages in the acquisition of resistance genes.
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Affiliation(s)
- Belinda Loh
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, China
| | - Jiayuan Chen
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, China
| | - Prasanth Manohar
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Sebastian Leptihn
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, China
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- University of Edinburgh Medical School, Biomedical Sciences, College of Medicine & Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
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20
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Roach TNF, Little M, Arts MGI, Huckeba J, Haas AF, George EE, Quinn RA, Cobián-Güemes AG, Naliboff DS, Silveira CB, Vermeij MJA, Kelly LW, Dorrestein PC, Rohwer F. A multiomic analysis of in situ coral-turf algal interactions. Proc Natl Acad Sci U S A 2020; 117:13588-13595. [PMID: 32482859 PMCID: PMC7306781 DOI: 10.1073/pnas.1915455117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Viruses, microbes, and host macroorganisms form ecological units called holobionts. Here, a combination of metagenomic sequencing, metabolomic profiling, and epifluorescence microscopy was used to investigate how the different components of the holobiont including bacteria, viruses, and their associated metabolites mediate ecological interactions between corals and turf algae. The data demonstrate that there was a microbial assemblage unique to the coral-turf algae interface displaying higher microbial abundances and larger microbial cells. This was consistent with previous studies showing that turf algae exudates feed interface and coral-associated microbial communities, often at the detriment of the coral. Further supporting this hypothesis, when the metabolites were assigned a nominal oxidation state of carbon (NOSC), we found that the turf algal metabolites were significantly more reduced (i.e., have higher potential energy) compared to the corals and interfaces. The algae feeding hypothesis was further supported when the ecological outcomes of interactions (e.g., whether coral was winning or losing) were considered. For example, coral holobionts losing the competition with turf algae had higher Bacteroidetes-to-Firmicutes ratios and an elevated abundance of genes involved in bacterial growth and division. These changes were similar to trends observed in the obese human gut microbiome, where overfeeding of the microbiome creates a dysbiosis detrimental to the long-term health of the metazoan host. Together these results show that there are specific biogeochemical changes at coral-turf algal interfaces that predict the competitive outcomes between holobionts and are consistent with algal exudates feeding coral-associated microbes.
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Affiliation(s)
- Ty N F Roach
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI 96744;
- Biosphere 2, University of Arizona, Oracle, AZ 85739
- Department of Biology, San Diego State University, San Diego, CA 92182
- Viral Information Institute, San Diego State University, San Diego, CA 92182
| | - Mark Little
- Department of Biology, San Diego State University, San Diego, CA 92182
- Viral Information Institute, San Diego State University, San Diego, CA 92182
| | - Milou G I Arts
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE, Amsterdam, The Netherlands
- Royal Netherlands Institute for Sea Research (NIOZ), Utrecht University, 1790 AB, Den Burg, Texel, The Netherlands
- Department of Botany, University of British Columbia, Vancouver, BC, Canada V6T1Z4
| | - Joel Huckeba
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE, Amsterdam, The Netherlands
| | - Andreas F Haas
- Royal Netherlands Institute for Sea Research (NIOZ), Utrecht University, 1790 AB, Den Burg, Texel, The Netherlands
| | - Emma E George
- Department of Botany, University of British Columbia, Vancouver, BC, Canada V6T1Z4
| | - Robert A Quinn
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48823
| | | | | | - Cynthia B Silveira
- Department of Biology, San Diego State University, San Diego, CA 92182
- Viral Information Institute, San Diego State University, San Diego, CA 92182
| | - Mark J A Vermeij
- Royal Netherlands Institute for Sea Research (NIOZ), Utrecht University, 1790 AB, Den Burg, Texel, The Netherlands
- Caribbean Research and Management of Biodiversity (CARMABI), Willemstad, Curaçao
| | | | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, CA 92182;
- Viral Information Institute, San Diego State University, San Diego, CA 92182
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21
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Silveira CB, Coutinho FH, Cavalcanti GS, Benler S, Doane MP, Dinsdale EA, Edwards RA, Francini-Filho RB, Thompson CC, Luque A, Rohwer FL, Thompson F. Genomic and ecological attributes of marine bacteriophages encoding bacterial virulence genes. BMC Genomics 2020; 21:126. [PMID: 32024463 PMCID: PMC7003362 DOI: 10.1186/s12864-020-6523-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/21/2020] [Indexed: 12/14/2022] Open
Abstract
Background Bacteriophages encode genes that modify bacterial functions during infection. The acquisition of phage-encoded virulence genes is a major mechanism for the rise of bacterial pathogens. In coral reefs, high bacterial density and lysogeny has been proposed to exacerbate reef decline through the transfer of phage-encoded virulence genes. However, the functions and distribution of these genes in phage virions on the reef remain unknown. Results Here, over 28,000 assembled viral genomes from the free viral community in Atlantic and Pacific Ocean coral reefs were queried against a curated database of virulence genes. The diversity of virulence genes encoded in the viral genomes was tested for relationships with host taxonomy and bacterial density in the environment. These analyses showed that bacterial density predicted the profile of virulence genes encoded by phages. The Shannon diversity of virulence-encoding phages was negatively related with bacterial density, leading to dominance of fewer genes at high bacterial abundances. A statistical learning analysis showed that reefs with high microbial density were enriched in viruses encoding genes enabling bacterial recognition and invasion of metazoan epithelium. Over 60% of phages could not have their hosts identified due to limitations of host prediction tools; for those which hosts were identified, host taxonomy was not an indicator of the presence of virulence genes. Conclusions This study described bacterial virulence factors encoded in the genomes of bacteriophages at the community level. The results showed that the increase in microbial densities that occurs during coral reef degradation is associated with a change in the genomic repertoire of bacteriophages, specifically in the diversity and distribution of bacterial virulence genes. This suggests that phages are implicated in the rise of pathogens in disturbed marine ecosystems.
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Affiliation(s)
- Cynthia B Silveira
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA. .,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA. .,Department of Biology, University of Miami, 1301 Memorial Dr., Coral Gables, FL, 33146, USA.
| | - Felipe H Coutinho
- Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, Apartado 18, 03550, San Juan de Alicante, Spain
| | - Giselle S Cavalcanti
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Sean Benler
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Michael P Doane
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Sydney Institute of Marine Science, 19 Chowder Bay Rd, Mosman, NSW, 2088, Australia
| | - Elizabeth A Dinsdale
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Robert A Edwards
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Ronaldo B Francini-Filho
- Centro de Biologia Marinha, Universidade de São Paulo, Rodovia Manoel Hypólito do Rego, Km 131,50, São Sebastião, SP, 11600-000, Brazil
| | - Cristiane C Thompson
- Instituto de Biologia, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Rio de Janeiro, RJ, 21941- 599, Brazil
| | - Antoni Luque
- Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Department of Mathematics and Statistics, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Computational Science Research Center, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Forest L Rohwer
- Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
| | - Fabiano Thompson
- SAGE/COPPE, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Rio de Janeiro, RJ, 21941- 599, Brazil
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22
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Haselkorn TS, DiSalvo S, Miller JW, Bashir U, Brock DA, Queller DC, Strassmann JE. The specificity of Burkholderia symbionts in the social amoeba farming symbiosis: Prevalence, species, genetic and phenotypic diversity. Mol Ecol 2019; 28:847-862. [PMID: 30575161 DOI: 10.1111/mec.14982] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/13/2018] [Accepted: 10/25/2018] [Indexed: 01/10/2023]
Abstract
The establishment of symbioses between eukaryotic hosts and bacterial symbionts in nature is a dynamic process. The formation of such relationships depends on the life history of both partners. Bacterial symbionts of amoebae may have unique evolutionary trajectories to the symbiont lifestyle, because bacteria are typically ingested as prey. To persist after ingestion, bacteria must first survive phagocytosis. In the social amoeba Dictyostelium discoideum, certain strains of Burkholderia bacteria are able to resist amoebal digestion and maintain a persistent relationship that includes carriage throughout the amoeba's social cycle that culminates in spore formation. Some Burkholderia strains allow their host to carry other bacteria, as food. This carried food is released in new environments in a trait called farming. To better understand the diversity and prevalence of Burkholderia symbionts and the traits they impart to their amoebae hosts, we first screened 700 natural isolates of D. discoideum and found 25% infected with Burkholderia. We next used a multilocus phylogenetic analysis and identified two independent transitions by Burkholderia to the symbiotic lifestyle. Finally, we tested the ability of 38 strains of Burkholderia from D. discoideum, as well as strains isolated from other sources, for traits relevant to symbiosis in D. discoideum. Only D. discoideum native isolates belonging to the Burkholderia agricolaris, B. hayleyella, and B. bonniea species were able to form persistent symbiotic associations with D. discoideum. The Burkholderia-Dictyostelium relationship provides a promising arena for further studies of the pathway to symbiosis in a unique system.
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Affiliation(s)
| | - Susanne DiSalvo
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois
| | - Jacob W Miller
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois
| | - Usman Bashir
- Department of Biology, Washington University in St. Louis, Missouri
| | - Debra A Brock
- Department of Biology, Washington University in St. Louis, Missouri
| | - David C Queller
- Department of Biology, Washington University in St. Louis, Missouri
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23
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Vaqué D, Lara E, Arrieta JM, Holding J, Sà EL, Hendriks IE, Coello-Camba A, Alvarez M, Agustí S, Wassmann PF, Duarte CM. Warming and CO 2 Enhance Arctic Heterotrophic Microbial Activity. Front Microbiol 2019; 10:494. [PMID: 30949141 PMCID: PMC6436474 DOI: 10.3389/fmicb.2019.00494] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 02/26/2019] [Indexed: 11/13/2022] Open
Abstract
Ocean acidification and warming are two main consequences of climate change that can directly affect biological and ecosystem processes in marine habitats. The Arctic Ocean is the region of the world experiencing climate change at the steepest rate compared with other latitudes. Since marine planktonic microorganisms play a key role in the biogeochemical cycles in the ocean it is crucial to simultaneously evaluate the effect of warming and increasing CO2 on marine microbial communities. In 20 L experimental microcosms filled with water from a high-Arctic fjord (Svalbard), we examined changes in phototrophic and heterotrophic microbial abundances and processes [bacterial production (BP) and mortality], and viral activity (lytic and lysogenic) in relation to warming and elevated CO2. The summer microbial plankton community living at 1.4°C in situ temperature, was exposed to increased CO2 concentrations (135–2,318 μatm) in three controlled temperature treatments (1, 6, and 10°C) at the UNIS installations in Longyearbyen (Svalbard), in summer 2010. Results showed that chlorophyll a concentration decreased at increasing temperatures, while BP significantly increased with pCO2 at 6 and 10°C. Lytic viral production was not affected by changes in pCO2 and temperature, while lysogeny increased significantly at increasing levels of pCO2, especially at 10°C (R2 = 0.858, p = 0.02). Moreover, protistan grazing rates showed a positive interaction between pCO2 and temperature. The averaged percentage of bacteria grazed per day was higher (19.56 ± 2.77% d-1) than the averaged percentage of lysed bacteria by virus (7.18 ± 1.50% d-1) for all treatments. Furthermore, the relationship among microbial abundances and processes showed that BP was significantly related to phototrophic pico/nanoflagellate abundance in the 1°C and the 6°C treatments, and BP triggered viral activity, mainly lysogeny at 6 and 10°C, while bacterial mortality rates was significantly related to bacterial abundances at 6°C. Consequently, our experimental results suggested that future increases in water temperature and pCO2 in Arctic waters will produce a decrease of phytoplankton biomass, enhancement of BP and changes in the carbon fluxes within the microbial food web. All these heterotrophic processes will contribute to weakening the CO2 sink capacity of the Arctic plankton community.
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Affiliation(s)
- Dolors Vaqué
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Barcelona, Spain
| | - Elena Lara
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Barcelona, Spain
| | - Jesús M Arrieta
- Centro Oceanográfico de Canarias (IEO), Santa Cruz de Tenerife, Spain
| | - Johnna Holding
- Global Change Research Group, IMEDEA (CSIC-UIB) Institut Mediterrani d'Estudis Avançats, Esporles, Spain.,Arctic Research Centre, Aarhus University, Aarhus, Denmark
| | - Elisabet L Sà
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Barcelona, Spain
| | - Iris E Hendriks
- Global Change Research Group, IMEDEA (CSIC-UIB) Institut Mediterrani d'Estudis Avançats, Esporles, Spain
| | - Alexandra Coello-Camba
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Susana Agustí
- Global Change Research Group, IMEDEA (CSIC-UIB) Institut Mediterrani d'Estudis Avançats, Esporles, Spain.,Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Paul F Wassmann
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, Tromsø, Norway
| | - Carlos M Duarte
- Global Change Research Group, IMEDEA (CSIC-UIB) Institut Mediterrani d'Estudis Avançats, Esporles, Spain.,Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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24
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Gao Z, Karlsson I, Geisen S, Kowalchuk G, Jousset A. Protists: Puppet Masters of the Rhizosphere Microbiome. TRENDS IN PLANT SCIENCE 2019; 24:165-176. [PMID: 30446306 DOI: 10.1016/j.tplants.2018.10.011] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 05/18/2023]
Abstract
The rhizosphere microbiome is a central determinant of plant performance. Microbiome assembly has traditionally been investigated from a bottom-up perspective, assessing how resources such as root exudates drive microbiome assembly. However, the importance of predation as a driver of microbiome structure has to date largely remained overlooked. Here we review the importance of protists, a paraphyletic group of unicellular eukaryotes, as a key regulator of microbiome assembly. Protists can promote plant-beneficial functions within the microbiome, accelerate nutrient cycling, and remove pathogens. We conclude that protists form an essential component of the rhizosphere microbiome and that accounting for predator-prey interactions would greatly improve our ability to predict and manage microbiome function at the service of plant growth and health.
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Affiliation(s)
- Zhilei Gao
- Institute of Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; These authors contributed equally
| | - Ida Karlsson
- Institute of Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; Dept. of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, 75007 Uppsala, Sweden; These authors contributed equally
| | - Stefan Geisen
- Department of Terrestrial Ecology, Netherlands Institute of Ecology, 6708 PB Wageningen, The Netherlands
| | - George Kowalchuk
- Institute of Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Alexandre Jousset
- Institute of Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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25
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Lancaster CE, Ho CY, Hipolito VEB, Botelho RJ, Terebiznik MR. Phagocytosis: what's on the menu? 1. Biochem Cell Biol 2018; 97:21-29. [PMID: 29791809 DOI: 10.1139/bcb-2018-0008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phagocytosis is an evolutionarily conserved process. In Protozoa, phagocytosis fulfills a feeding mechanism, while in Metazoa, phagocytosis diversified to play multiple organismal roles, including immune defence, tissue homeostasis, and remodeling. Accordingly, phagocytes display a high level of plasticity in their capacity to recognize, engulf, and process targets that differ in composition and morphology. Here, we review how phagocytosis adapts to its multiple roles and discuss in particular the effect of target morphology in phagocytic uptake and phagosome maturation.
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Affiliation(s)
- Charlene E Lancaster
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada.,b Department of Cell and System Biology, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
| | - Cheuk Y Ho
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
| | - Victoria E B Hipolito
- c Molecular Science Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada.,d Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Roberto J Botelho
- c Molecular Science Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada.,d Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Mauricio R Terebiznik
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada.,b Department of Cell and System Biology, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
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26
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Geisen S, Mitchell EAD, Adl S, Bonkowski M, Dunthorn M, Ekelund F, Fernández LD, Jousset A, Krashevska V, Singer D, Spiegel FW, Walochnik J, Lara E. Soil protists: a fertile frontier in soil biology research. FEMS Microbiol Rev 2018; 42:293-323. [DOI: 10.1093/femsre/fuy006] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 02/12/2018] [Indexed: 12/27/2022] Open
Affiliation(s)
- Stefan Geisen
- Department of Terrestrial Ecology, Netherlands Institute of Ecology, 6708 PB Wageningen, The Netherlands
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Edward A D Mitchell
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
- Jardin Botanique de Neuchâtel, Chemin du Perthuis-du-Sault 58, Neuchâtel 2000, Switzerland
| | - Sina Adl
- Department of Soil Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, Canada
| | - Michael Bonkowski
- Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Institute of Zoology, Terrestrial Ecology, Zülpicher Straße 47b, 50674 Köln, Germany
| | - Micah Dunthorn
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger Straße, 67663 Kaiserslautern, Germany
| | - Flemming Ekelund
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Leonardo D Fernández
- Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS), Universidad Bernardo O’Higgins, Avenida Viel 1497, Santiago, Chile
| | - Alexandre Jousset
- Department of Ecology and Biodiversity, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Valentyna Krashevska
- University of Göttingen, J.F. Blumenbach Institute of Zoology and Anthropology, Untere Karspüle 2, 37073 Göttingen, Germany
| | - David Singer
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
| | - Frederick W Spiegel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, United States of America
| | - Julia Walochnik
- Molecular Parasitology, Institute of Tropical Medicine, Medical University, 1090 Vienna, Austria
| | - Enrique Lara
- Laboratory of Soil Biodiversity, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel 2000, Switzerland
- Real Jardín Botánico, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain
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27
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Abstract
Long before bacteria infected humans, they infected amoebas, which remain a potentially important reservoir for human disease. Diverse soil amoebas including Dictyostelium and Acanthamoeba can host intracellular bacteria. Though the internal environment of free-living amoebas is similar in many ways to that of mammalian macrophages, they differ in a number of important ways, including temperature. A new study in PLOS Biology by Taylor-Mulneix et al. demonstrates that Bordetella bronchiseptica has two different gene suites that are activated depending on whether the bacterium finds itself in a hot mammalian or cool amoeba host environment. This study specifically shows that B. bronchiseptica not only inhabits amoebas but can persist and multiply through the social stage of an amoeba host, Dictyostelium discoideum.
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28
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Arnold JW, Spacht D, Koudelka GB. Determinants that govern the recognition and uptake of
Escherichia coli
O157 : H7 by
Acanthamoeba castellanii. Cell Microbiol 2016; 18:1459-70. [DOI: 10.1111/cmi.12591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Jason W. Arnold
- Department of Biological Sciences University at Buffalo Buffalo NY 14260 USA
| | - Drew Spacht
- Department of Biology Mercyhurst University Erie PA 16546 USA
- Department of Entomology The Ohio State University 318 W. 12th Ave. 300 Aronoff Laboratory Columbus OH 43210 USA
| | - Gerald B. Koudelka
- Department of Biological Sciences University at Buffalo Buffalo NY 14260 USA
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29
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A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon Pantoea ananatis BRT175 against the Social Amoeba Dictyostelium discoideum. mSphere 2016; 1:mSphere00075-15. [PMID: 27303689 PMCID: PMC4863597 DOI: 10.1128/msphere.00075-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 11/20/2022] Open
Abstract
Pantoea is a versatile genus of bacteria with both plant- and animal-pathogenic strains, some of which have been suggested to cause human infections. There is, however, limited knowledge on the potential determinants used for host association and pathogenesis in animal systems. In this study, we used the model host Dictyostelium discoideum to show that isolates of Pantoea ananatis exhibit differential grazing susceptibility, with some being resistant to grazing by the amoebae. We carried out a high-throughput genetic screen of one grazing-resistant isolate, P. ananatis BRT175, using the D. discoideum pathosystem to identify genes responsible for the resistance phenotype. Among the 26 candidate genes involved in grazing resistance, we identified rhlA and rhlB, which we show are involved in the biosynthesis of a biosurfactant that enables swarming motility in P. ananatis BRT175. Using liquid chromatography-mass spectrometry (LC-MS), the biosurfactant was shown to be a glycolipid with monohexose-C10-C10 as the primary congener. We show that this novel glycolipid biosurfactant is cytotoxic to the amoebae and is capable of compromising cellular integrity, leading to cell lysis. The production of this biosurfactant may be important for bacterial survival in the environment and could contribute to the establishment of opportunistic infections. IMPORTANCE The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections.
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30
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Overstreet RM, Lotz JM. Host–Symbiont Relationships: Understanding the Change from Guest to Pest. ADVANCES IN ENVIRONMENTAL MICROBIOLOGY 2016. [PMCID: PMC7123458 DOI: 10.1007/978-3-319-28170-4_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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31
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Durzyńska J, Goździcka-Józefiak A. Viruses and cells intertwined since the dawn of evolution. Virol J 2015; 12:169. [PMID: 26475454 PMCID: PMC4609113 DOI: 10.1186/s12985-015-0400-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 10/07/2015] [Indexed: 12/24/2022] Open
Abstract
Many attempts have been made to define nature of viruses and to uncover their origin. Our aim within this work was to show that there are different perceptions of viruses and many concepts to explain their emergence: the virus-first concept (also called co-evolution), the escape and the reduction theories. Moreover, a relatively new concept of polyphyletic virus origin called “three RNA cells, three DNA viruses” proposed by Forterre is described herein. In this paper, not only is each thesis supported by a body of evidence but also counter-argued in the light of various findings to give more insightful considerations to the readers. As the origin of viruses and that of living cells are most probably interdependent, we decided to reveal ideas concerning nature of cellular last universal common ancestor (LUCA). Furthermore, we discuss monophyletic ancestry of cellular domains and their relationships at the molecular level of membrane lipids and replication strategies of these three types of cells. In this review, we also present the emergence of DNA viruses requiring an evolutionary transition from RNA to DNA and recently discovered giant DNA viruses possibly involved in eukaryogenesis. In the course of evolution viruses emerged many times. They have always played a key role through horizontal gene transfer in evolutionary events and in formation of the tree of life or netlike routes of evolution providing a great deal of genetic diversity. In our opinion, future findings are crucial to better understand past relations between viruses and cells and the origin of both.
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Affiliation(s)
- Julia Durzyńska
- Department of Molecular Virology, Institute of Experimental Biology, Faculty of Biology, A. Mickiewicz University, ul. Umultowska 89, 61-614, Poznań, Poland.
| | - Anna Goździcka-Józefiak
- Department of Molecular Virology, Institute of Experimental Biology, Faculty of Biology, A. Mickiewicz University, ul. Umultowska 89, 61-614, Poznań, Poland
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32
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Transcriptome reprogramming by plasmid-encoded transcriptional regulators is required for host niche adaption of a macrophage pathogen. Infect Immun 2015; 83:3137-45. [PMID: 26015480 DOI: 10.1128/iai.00230-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/18/2015] [Indexed: 11/20/2022] Open
Abstract
Rhodococcus equi is a facultative intracellular pathogen of macrophages, relying on the presence of a conjugative virulence plasmid harboring a 21-kb pathogenicity island (PAI) for growth in host macrophages. The PAI encodes a family of 6 virulence-associated proteins (Vaps) in addition to 20 other proteins. The contribution of these to virulence has remained unclear. We show that the presence of only 3 virulence plasmid genes (of 73 in total) is required and sufficient for intracellular growth. These include a single vap family member, vapA, and two PAI-located transcriptional regulators, virR and virS. Both transcriptional regulators are essential for wild-type-level expression of vapA, yet vapA expression alone is not sufficient to allow intracellular growth. A whole-genome microarray analysis revealed that VirR and VirS substantially integrate themselves into the chromosomal regulatory network, significantly altering the transcription of 18% of all chromosomal genes. This pathoadaptation involved significant enrichment of select gene ontologies, in particular, enrichment of genes involved in transport processes, energy production, and cellular metabolism, suggesting a major change in cell physiology allowing the bacterium to grow in the hostile environment of the host cell. The results suggest that following the acquisition of the virulence plasmid by an avirulent ancestor of R. equi, coevolution between the plasmid and the chromosome took place, allowing VirR and VirS to regulate the transcription of chromosomal genes in a process that ultimately promoted intracellular growth. Our findings suggest a mechanism for cooption of existing chromosomal traits during the evolution of a pathogenic bacterium from an avirulent saprophyte.
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33
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Zhang J, Ketola T, Örmälä-Odegrip AM, Mappes J, Laakso J. Coincidental loss of bacterial virulence in multi-enemy microbial communities. PLoS One 2014; 9:e111871. [PMID: 25365586 PMCID: PMC4218854 DOI: 10.1371/journal.pone.0111871] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 10/03/2014] [Indexed: 01/17/2023] Open
Abstract
The coincidental virulence evolution hypothesis suggests that outside-host selection, such as predation, parasitism and resource competition can indirectly affect the virulence of environmentally-growing bacterial pathogens. While there are some examples of coincidental environmental selection for virulence, it is also possible that the resource acquisition and enemy defence is selecting against it. To test these ideas we conducted an evolutionary experiment by exposing the opportunistic pathogen bacterium Serratia marcescens to the particle-feeding ciliate Tetrahymena thermophila, the surface-feeding amoeba Acanthamoeba castellanii, and the lytic bacteriophage Semad11, in all possible combinations in a simulated pond water environment. After 8 weeks the virulence of the 384 evolved clones were quantified with fruit fly Drosophila melanogaster oral infection model, and several other life-history traits were measured. We found that in comparison to ancestor bacteria, evolutionary treatments reduced the virulence in most of the treatments, but this reduction was not clearly related to any changes in other life-history traits. This suggests that virulence traits do not evolve in close relation with these life-history traits, or that different traits might link to virulence in different selective environments, for example via resource allocation trade-offs.
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Affiliation(s)
- Ji Zhang
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Biological and Environmental Science, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Tarmo Ketola
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | | | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Jouni Laakso
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Biological and Environmental Science, University of Helsinki, Helsinki, Finland
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34
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Jackson RW, Vinatzer B, Arnold DL, Dorus S, Murillo J. The influence of the accessory genome on bacterial pathogen evolution. Mob Genet Elements 2014; 1:55-65. [PMID: 22016845 DOI: 10.4161/mge.1.1.16432] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/09/2011] [Accepted: 05/10/2011] [Indexed: 01/15/2023] Open
Abstract
Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens' frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorize the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution.
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Affiliation(s)
- Robert W Jackson
- School of Biological Sciences; University of Reading; Whiteknights; Reading, UK
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35
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Phages can constrain protist predation-driven attenuation of Pseudomonas aeruginosa virulence in multienemy communities. ISME JOURNAL 2014; 8:1820-30. [PMID: 24671085 DOI: 10.1038/ismej.2014.40] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 02/18/2014] [Accepted: 02/23/2014] [Indexed: 11/08/2022]
Abstract
The coincidental theory of virulence predicts that bacterial pathogenicity could be a by-product of selection by natural enemies in environmental reservoirs. However, current results are ambiguous and the simultaneous impact of multiple ubiquitous enemies, protists and phages on virulence evolution has not been investigated previously. Here we tested experimentally how Tetrahymena thermophila protist predation and PNM phage parasitism (bacteria-specific virus) alone and together affect the evolution of Pseudomonas aeruginosa PAO1 virulence, measured in wax moth larvae. Protist predation selected for small colony types, both in the absence and presence of phage, which showed decreased edibility to protists, reduced growth in the absence of enemies and attenuated virulence. Although phage selection alone did not affect the bacterial phenotype, it weakened protist-driven antipredatory defence (biofilm formation), its associated pleiotropic growth cost and the correlated reduction in virulence. These results suggest that protist selection can be a strong coincidental driver of attenuated bacterial virulence, and that phages can constrain this effect owing to effects on population dynamics and conflicting selection pressures. Attempting to define causal links such as these might help us to predict the cold and hot spots of coincidental virulence evolution on the basis of microbial community composition of environmental reservoirs.
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36
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Jacquier N, Aeby S, Lienard J, Greub G. Discovery of new intracellular pathogens by amoebal coculture and amoebal enrichment approaches. J Vis Exp 2013:e51055. [PMID: 24192667 DOI: 10.3791/51055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Intracellular pathogens such as legionella, mycobacteria and Chlamydia-like organisms are difficult to isolate because they often grow poorly or not at all on selective media that are usually used to cultivate bacteria. For this reason, many of these pathogens were discovered only recently or following important outbreaks. These pathogens are often associated with amoebae, which serve as host-cell and allow the survival and growth of the bacteria. We intend here to provide a demonstration of two techniques that allow isolation and characterization of intracellular pathogens present in clinical or environmental samples: the amoebal coculture and the amoebal enrichment. Amoebal coculture allows recovery of intracellular bacteria by inoculating the investigated sample onto an amoebal lawn that can be infected and lysed by the intracellular bacteria present in the sample. Amoebal enrichment allows recovery of amoebae present in a clinical or environmental sample. This can lead to discovery of new amoebal species but also of new intracellular bacteria growing specifically in these amoebae. Together, these two techniques help to discover new intracellular bacteria able to grow in amoebae. Because of their ability to infect amoebae and resist phagocytosis, these intracellular bacteria might also escape phagocytosis by macrophages and thus, be pathogenic for higher eukaryotes.
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Affiliation(s)
- Nicolas Jacquier
- Institute of Microbiology, University Hospital Center and University of Lausanne
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Arnold JW, Koudelka GB. The Trojan Horse of the microbiological arms race: phage-encoded toxins as a defence against eukaryotic predators. Environ Microbiol 2013; 16:454-66. [PMID: 23981100 DOI: 10.1111/1462-2920.12232] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 07/17/2013] [Accepted: 07/28/2013] [Indexed: 12/31/2022]
Abstract
Phage-encoded Shiga toxin (Stx) acts as a bacterial defence against the eukaryotic predator Tetrahymena. To function as an effective bacterial anti-predator defence, Stx must kill a broad spectrum of predators. Consistent with that assertion, we show here that bacterially encoded Stx efficiently kills the bacteriovore Acanthamoeba castellanii in co-culture. We also show that, in addition to Stx, the phage-encoded exotoxin, diphtheria toxin (Dtx) expressed by Corynebacterium diphtheriae also can function as part of an anti-predator strategy; it kills Acanthamoeba in co-culture. Interestingly, only exotoxins produced by bacteria internalized by the Acanthamoeba predator are cytolethal; the presence of purified Dtx or Stx in culture medium has no effect on predator viability. This finding is consistent with our results indicating that intoxication of Acanthamoeba by these exotoxins does not require a receptor. Thus bacteria, in the disguise of a food source, function as a 'Trojan Horse', carrying genes encoding an exotoxin into target organisms. This 'Trojan Horse' mechanism of exotoxin delivery into predator cells allows intoxication of predators that lack a cell surface receptor for the particular toxin, allowing bacteria-bearing exotoxins to kill a broader spectrum of predators, increasing the fitness of the otherwise 'defenceless' prey bacteria.
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Affiliation(s)
- Jason W Arnold
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA
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Ketola T, Mikonranta L, Zhang J, Saarinen K, Örmälä AM, Friman VP, Mappes J, Laakso J. FLUCTUATING TEMPERATURE LEADS TO EVOLUTION OF THERMAL GENERALISM AND PREADAPTATION TO NOVEL ENVIRONMENTS. Evolution 2013; 67:2936-44. [DOI: 10.1111/evo.12148] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 04/11/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Tarmo Ketola
- Centre of Excellence in Biological Interactions; Department of Biological and Environmental Science; University of Jyväskylä; P.O. Box 35; Jyväskylä; FI-40014; Finland
| | - Lauri Mikonranta
- Centre of Excellence in Biological Interactions; Department of Biological and Environmental Science; University of Jyväskylä; P.O. Box 35; Jyväskylä; FI-40014; Finland
| | - Ji Zhang
- Centre of Excellence in Biological Interactions; Department of Biological and Environmental Science; University of Jyväskylä; P.O. Box 35; Jyväskylä; FI-40014; Finland
| | - Kati Saarinen
- Centre of Excellence in Biological Interactions; Department of Biological and Environmental Science; University of Jyväskylä; P.O. Box 35; Jyväskylä; FI-40014; Finland
| | | | - Ville-Petri Friman
- Biosciences; University of Exeter; Cornwall Campus; Penryn; TR10 9EZ; United Kingdom
| | - Johanna Mappes
- Centre of Excellence in Biological Interactions; Department of Biological and Environmental Science; University of Jyväskylä; P.O. Box 35; Jyväskylä; FI-40014; Finland
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Horton RE, Grant GD, Matthews B, Batzloff M, Owen SJ, Kyan S, Flegg CP, Clark AM, Ulett GC, Morrison N, Peak IR, Beacham IR. Quorum sensing negatively regulates multinucleate cell formation during intracellular growth of Burkholderia pseudomallei in macrophage-like cells. PLoS One 2013; 8:e63394. [PMID: 23704903 PMCID: PMC3660431 DOI: 10.1371/journal.pone.0063394] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/01/2013] [Indexed: 01/29/2023] Open
Abstract
Burkholderia pseudomallei is a Gram-negative environmental bacterium and the causative agent of melioidosis, a potentially fatal, acute or chronic disease endemic in the tropics. Acyl homoserine lactone (AHL)-mediated quorum sensing and signalling have been associated with virulence and biofilm formation in numerous bacterial pathogens. In the canonical acyl-homoserine lactone signalling paradigm, AHLs are detected by a response regulator. B. pseudomallei encodes three AHL synthases, encoded by bpsI1, bpsI2 and bpsI3, and five regulator genes. In this study, we mutated the B. pseudomallei AHL synthases individually and in double and triple combination. Five AHLs were detected and quantified by tandem liquid chromatography-mass spectroscopy. The major AHLs produced were N-octanoylhomoserine lactone and N-(3-hydroxy-decanoyl)homoserine lactone, the expression of which depended on bpsI1 and bpsI2, respectively. B. pseudomallei infection of macrophage cells causes cell fusion, leading to multinucleated cells (3 or more nuclei per cell). A triple mutant defective in production of all three AHL synthases was associated with a striking phenotype of massively enhanced host cellular fusion in macrophages. However, neither abrogation of host cell fusion, achieved by mutation of bimA or hcp1, nor enhancement of fusion altered intracellular replication of B. pseudomallei. Furthermore, when tested in murine models of acute melioidosis the AHL synthase mutants were not attenuated for virulence. Collectively, this study identifies important new aspects of the genetic basis of AHL synthesis in B. pseudomallei and the roles of these AHLs in systemic infection and in cell fusion in macrophages for this important human pathogen.
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Affiliation(s)
- Rachel E. Horton
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Gary D. Grant
- School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Ben Matthews
- Smart Water Research Centre, Griffith University, Gold Coast, Queensland, Australia
| | - Michael Batzloff
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Suzzanne J. Owen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Stephanie Kyan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Cameron P. Flegg
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Amanda M. Clark
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Glen C. Ulett
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Nigel Morrison
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Ian R. Peak
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Ifor R. Beacham
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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Dutilh BE, Backus L, Edwards RA, Wels M, Bayjanov JR, van Hijum SAFT. Explaining microbial phenotypes on a genomic scale: GWAS for microbes. Brief Funct Genomics 2013; 12:366-80. [PMID: 23625995 PMCID: PMC3743258 DOI: 10.1093/bfgp/elt008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
There is an increasing availability of complete or draft genome sequences for microbial organisms. These data form a potentially valuable resource for genotype-phenotype association and gene function prediction, provided that phenotypes are consistently annotated for all the sequenced strains. In this review, we address the requirements for successful gene-trait matching. We outline a basic protocol for microbial functional genomics, including genome assembly, annotation of genotypes (including single nucleotide polymorphisms, orthologous groups and prophages), data pre-processing, genotype-phenotype association, visualization and interpretation of results. The methodologies for association described herein can be applied to other data types, opening up possibilities to analyze transcriptome-phenotype associations, and correlate microbial population structure or activity, as measured by metagenomics, to environmental parameters.
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Affiliation(s)
- Bas E Dutilh
- CMBI, NCMLS, Radboud University Medical Centre. Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands.
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Saussereau E, Debarbieux L. Bacteriophages in the experimental treatment of Pseudomonas aeruginosa infections in mice. Adv Virus Res 2012; 83:123-41. [PMID: 22748810 DOI: 10.1016/b978-0-12-394438-2.00004-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The regular increase of drug-resistant pathogens has been a major force in the renewed interest in the use of bacteriophages as therapeutics. In addition to experience acquired in eastern Europe where bacteriophages have been used to treat bacterial infections in humans, in Western countries only experimental models have been developed until recently. The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen causing particularly severe infections in cystic fibrosis patients. Several experimental models in mice have yielded encouraging results for the use of bacteriophages to treat or prevent septicemia, skin and lungs infections caused by P. aeruginosa. Now, a phase II clinical trial conducted in the United Kingdom provides evidence for the efficacy of bacteriophage treatments in chronic otitis due to antibiotic-resistant P. aeruginosa strains. Together with experimental models, these results provide an incentive to develop more research and clinical studies to fully appreciate the benefits of the use of bacteriophages in medicine.
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Affiliation(s)
- Emilie Saussereau
- Institut Pasteur, Molecular Biology of the Gene in Extremophiles Unit, Department of Microbiology, Paris, France
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42
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Evolution of virulence in opportunistic pathogens: generalism, plasticity, and control. Trends Microbiol 2012; 20:336-42. [PMID: 22564248 PMCID: PMC3491314 DOI: 10.1016/j.tim.2012.04.005] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/30/2012] [Accepted: 04/12/2012] [Indexed: 01/15/2023]
Abstract
Standard virulence evolution theory assumes that virulence factors are maintained because they aid parasitic exploitation, increasing growth within and/or transmission between hosts. An increasing number of studies now demonstrate that many opportunistic pathogens (OPs) do not conform to these assumptions, with virulence factors maintained instead because of advantages in non-parasitic contexts. Here we review virulence evolution theory in the context of OPs and highlight the importance of incorporating environments outside a focal virulence site. We illustrate that virulence selection is constrained by correlations between these external and focal settings and pinpoint drivers of key environmental correlations, with a focus on generalist strategies and phenotypic plasticity. We end with a summary of key theoretical and empirical challenges to be met for a fuller understanding of OPs.
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Riley LM, Veses-Garcia M, Hillman JD, Handfield M, McCarthy AJ, Allison HE. Identification of genes expressed in cultures of E. coli lysogens carrying the Shiga toxin-encoding prophage Φ24B. BMC Microbiol 2012; 12:42. [PMID: 22439817 PMCID: PMC3342100 DOI: 10.1186/1471-2180-12-42] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 03/22/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Shigatoxigenic E. coli are a global and emerging health concern. Shiga toxin, Stx, is encoded on the genome of temperate, lambdoid Stx phages. Genes essential for phage maintenance and replication are encoded on approximately 50% of the genome, while most of the remaining genes are of unknown function nor is it known if these annotated hypothetical genes are even expressed. It is hypothesized that many of the latter have been maintained due to positive selection pressure, and that some, expressed in the lysogen host, have a role in pathogenicity. This study used Change Mediated Antigen Technology (CMAT)™ and 2D-PAGE, in combination with RT-qPCR, to identify Stx phage genes that are expressed in E. coli during the lysogenic cycle. RESULTS Lysogen cultures propagated for 5-6 hours produced a high cell density with a low proportion of spontaneous prophage induction events. The expression of 26 phage genes was detected in these cultures by differential 2D-PAGE of expressed proteins and CMAT. Detailed analyses of 10 of these genes revealed that three were unequivocally expressed in the lysogen, two expressed from a known lysogenic cycle promoter and one uncoupled from the phage regulatory network. CONCLUSION Propagation of a lysogen culture in which no cells at all are undergoing spontaneous lysis is impossible. To overcome this, RT-qPCR was used to determine gene expression profiles associated with the growth phase of lysogens. This enabled the definitive identification of three lambdoid Stx phage genes that are expressed in the lysogen and seven that are expressed during lysis. Conservation of these genes in this phage genome, and other Stx phages where they have been identified as present, indicates their importance in the phage/lysogen life cycle, with possible implications for the biology and pathogenicity of the bacterial host.
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Affiliation(s)
- Laura M Riley
- Microbiology Research Group, Institute of Integrative Biology, University of Liverpool, BioSciences Building, Crown Street, Liverpool L69 7ZB, UK
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Casas V, Maloy S. Role of bacteriophage-encoded exotoxins in the evolution of bacterial pathogens. Future Microbiol 2012; 6:1461-73. [PMID: 22122442 DOI: 10.2217/fmb.11.124] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent advances in metagenomics research have generated a bounty of information that provides insight into the dynamic genetic exchange occurring between bacteriophage (phage) and their bacterial hosts. Metagenomic studies of the microbiomes from a variety of environments have shown that many of the genes sequenced are of phage origin. Among these genes are phage-encoded exotoxin genes. When phage that carry these genes infect an appropriate bacterial host, the bacterium undergoes lysogenic conversion, converting the bacterium from an avirulent strain to a pathogen that can cause human disease. Transfer of the exotoxin genes between bacteria has been shown to occur in marine environments, animal and human intestines and sewage treatment plants. Surprisingly, phage that encode exotoxin genes are commonly found in environments that lack the cognate bacteria commonly associated with the specific toxin-mediated disease and have been found to be associated with alternative environmental bacterial hosts. These findings suggest that the exotoxin genes may play a beneficial role for the bacterial host in nature, and that this environmental reservoir of exotoxin genes may play a role in the evolution of new bacterial pathogens.
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Affiliation(s)
- Veronica Casas
- Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
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Abstract
All life must survive their corresponding viruses. Thus antiviral systems are essential in all living organisms. Remnants of virus derived information are also found in all life forms but have historically been considered mostly as junk DNA. However, such virus derived information can strongly affect host susceptibility to viruses. In this review, I evaluate the role viruses have had in the origin and evolution of host antiviral systems. From Archaea through bacteria and from simple to complex eukaryotes I trace the viral components that became essential elements of antiviral immunity. I conclude with a reexamination of the 'Big Bang' theory for the emergence of the adaptive immune system in vertebrates by horizontal transfer and note how viruses could have and did provide crucial and coordinated features.
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Viral ancestors of antiviral systems. Viruses 2011; 3:1933-58. [PMID: 22069523 PMCID: PMC3205389 DOI: 10.3390/v3101933] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/01/2011] [Accepted: 10/10/2011] [Indexed: 02/06/2023] Open
Abstract
All life must survive their corresponding viruses. Thus antiviral systems are essential in all living organisms. Remnants of virus derived information are also found in all life forms but have historically been considered mostly as junk DNA. However, such virus derived information can strongly affect host susceptibility to viruses. In this review, I evaluate the role viruses have had in the origin and evolution of host antiviral systems. From Archaea through bacteria and from simple to complex eukaryotes I trace the viral components that became essential elements of antiviral immunity. I conclude with a reexamination of the ‘Big Bang’ theory for the emergence of the adaptive immune system in vertebrates by horizontal transfer and note how viruses could have and did provide crucial and coordinated features.
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Friman VP, Hiltunen T, Jalasvuori M, Lindstedt C, Laanto E, Örmälä AM, Laakso J, Mappes J, Bamford JKH. High temperature and bacteriophages can indirectly select for bacterial pathogenicity in environmental reservoirs. PLoS One 2011; 6:e17651. [PMID: 21423610 PMCID: PMC3057980 DOI: 10.1371/journal.pone.0017651] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 02/08/2011] [Indexed: 01/19/2023] Open
Abstract
The coincidental evolution hypothesis predicts that traits connected to bacterial pathogenicity could be indirectly selected outside the host as a correlated response to abiotic environmental conditions or different biotic species interactions. To investigate this, an opportunistic bacterial pathogen, Serratia marcescens, was cultured in the absence and presence of the lytic bacteriophage PPV (Podoviridae) at 25°C and 37°C for four weeks (N = 5). At the end, we measured changes in bacterial phage-resistance and potential virulence traits, and determined the pathogenicity of all bacterial selection lines in the Parasemia plantaginis insect model in vivo. Selection at 37°C increased bacterial motility and pathogenicity but only in the absence of phages. Exposure to phages increased the phage-resistance of bacteria, and this was costly in terms of decreased maximum population size in the absence of phages. However, this small-magnitude growth cost was not greater with bacteria that had evolved in high temperature regime, and no trade-off was found between phage-resistance and growth rate. As a result, phages constrained the evolution of a temperature-mediated increase in bacterial pathogenicity presumably by preferably infecting the highly motile and virulent bacteria. In more general perspective, our results suggest that the traits connected to bacterial pathogenicity could be indirectly selected as a correlated response by abiotic and biotic factors in environmental reservoirs.
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Affiliation(s)
- Ville-Petri Friman
- Centre of Excellence in Evolutionary Research, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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Gregory R, Saunders V, Saunders J. Rule-based simulation of temperate bacteriophage infection: Restriction–modification as a limiter to infection in bacterial populations. Biosystems 2010; 100:166-77. [DOI: 10.1016/j.biosystems.2010.02.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 02/23/2010] [Accepted: 02/27/2010] [Indexed: 10/19/2022]
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50
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Forterre P, Prangishvili D. The great billion-year war between ribosome- and capsid-encoding organisms (cells and viruses) as the major source of evolutionary novelties. Ann N Y Acad Sci 2009; 1178:65-77. [PMID: 19845628 DOI: 10.1111/j.1749-6632.2009.04993.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Our conceptions on the origin, nature, and role of viruses have been shaken recently by several independent lines of research. There are many reasons to believe now that viruses are more ancient than modern cells and have always been more abundant and diverse than their cellular targets. Viruses can be defined as capsid-encoding organisms that transform their "host" cell into a viral factory. If capsid-encoding organisms (viruses) and ribosome-encoding organisms (cells) are the major types of living entities on our planet, it seems logical to conclude that their conflict has been a major engine of biological evolution (in the framework of natural selection). In particular, many novelties first selected in the viral world might have been transferred to cells as a consequence of the continuous flow of viral genes into cellular genomes. We discuss recent observations and hypotheses suggesting that viruses have played a major role at different stages of biological evolution, such as the RNA to DNA transition, the origin of the eukaryotic nucleus, or, alternatively, the origin of unique features in multicellular macrobes.
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