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Blair MF, Vaidya R, Salazar-Benites G, Bott CB, Pruden A. Relating microbial community composition to treatment performance in an ozone-biologically active carbon filtration potable reuse treatment train. WATER RESEARCH 2024; 262:122091. [PMID: 39047455 DOI: 10.1016/j.watres.2024.122091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/17/2024] [Accepted: 07/12/2024] [Indexed: 07/27/2024]
Abstract
Treatment trains that couple ozone (O3) with biologically active carbon (BAC) filtration are of interest as a lower cost, more sustainable, membrane-free approach to water reuse. However, little is known about the microbial communities that are the fundamental drivers of O3-BAC treatment. The objective of this study was to demonstrate microbial community profiling as a diagnostic tool for assessing the functionality, biological stability, and resilience of coupled physical, chemical, advanced oxidative and biological processes employed in water reuse treatment. We utilized 16S rRNA gene amplicon sequencing to profile the bacterial microbiota over time throughout a potable reuse train employing coagulation, flocculation, sedimentation, ozonation, BAC filtration, granular activated carbon (GAC) adsorption, and UV disinfection. A distinct baseline microbiota was associated with each stage of treatment (ANOSIM, p < 0.05, r-stat = 0.52), each undergoing succession with time and operational shifts. Ozonation resulted in the sharpest shifts (i.e., 83.3 % average change in Genus level relative abundances, when adjusted O3:TOC ratio > 1), and also variance, in microbial community composition. Adjustment in O3:TOC ratios, temperature, filter-aid polymer, monochloramine quenching agent, and empty-bed contact time also resulted in measurable changes in the baseline microbial community composition of individual processes, but to a lesser degree. Of these, supplementation of nitrogen and phosphorus resulted in the strongest bifurcation, especially in the microbial communities inhabiting the BAC (ANOSIM: p < 0.05, BAC5 r-stat = 0.32; BAC10 r-stat = 0.54) and GAC (ANOSIM: p < 0.05, GAC10 r-stat = 0.54; GAC20 r-stat = 0.63) units. Additionally, we found that the BAC microbial community was responsive to an inoculation of microbially active media, which resulted in improved TOC removal. The findings of this study improve understanding of bacterial dynamics occurring in advanced water treatment trains and can inform improved system design and operation.
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Affiliation(s)
- Matthew F Blair
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | | | | | - Charles B Bott
- Hampton Roads Sanitation District, Virginia Beach, VA, USA
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA.
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2
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Clinton M, Wyness AJ, Martin SAM, Brierley AS, Ferrier DEK. Association of microbial community structure with gill disease in marine-stage farmed Atlantic salmon (Salmo salar); a yearlong study. BMC Vet Res 2024; 20:340. [PMID: 39090695 PMCID: PMC11293161 DOI: 10.1186/s12917-024-04125-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/10/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND Understanding the relationship between resident microbiota and disease in cultured fish represents an important and emerging area of study. Marine gill disorders in particular are considered an important challenge to Atlantic salmon (Salmo salar) aquaculture, however relatively little is known regarding the role resident gill microbiota might play in providing protection from or potentiating different gill diseases. Here, 16S rRNA sequencing was used to examine the gill microbiome alongside fish health screening in farmed Atlantic salmon. Results were used to explore the relationship between microbial communities and gill disease. RESULTS Microbial community restructuring was observed throughout the sampling period and linked to varied drivers of change, including environmental conditions and severity of gill pathology. Taxa with significantly greater relative abundance on healthier gills included isolates within genus Shewanella, and taxa within family Procabacteriaceae. In contrast, altered abundance of Candidatus Branchiomonas and Rubritalea spp. were associated with damaged gills. Interestingly, more general changes in community richness and diversity were not associated with altered gill health, and thus not apparently deleterious to fish. Gross and histological gill scoring demonstrated seasonal shifts in gill pathology, with increased severity of gill damage in autumn. Specific infectious causes that contributed to observed pathology within the population included the gill disorder amoebic gill disease (AGD), however due to the uncontrolled nature of this study and likely mixed contribution of various causes of gill disease to observed pathology results do not strongly support an association between the microbial community and specific infectious or non-infectious drivers of gill pathology. CONCLUSIONS Results suggest that the microbial community of farmed Atlantic salmon gills undergo continual restructuring in the marine environment, with mixed influences upon this change including environmental, host, and pathogenic factors. A significant association of specific taxa with different gill health states suggests these taxa might make meaningful indicators of gill health. Further research with more frequent sampling and deliberate manipulation of gills would provide important advancement of knowledge in this area. Overall, although much is still to be learnt regarding what constitutes a healthy or maladapted gill microbial community, the results of this study provide clear advancement of the field, providing new insight into the microbial community structure of gills during an annual production cycle of marine-stage farmed Atlantic salmon.
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Affiliation(s)
- Morag Clinton
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK.
- Department of Veterinary Medicine, University of Alaska Fairbanks, Fairbanks, AK, USA.
- Sitka Sound Science Center, Alaska, Sitka, USA.
| | - Adam J Wyness
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK
- Scottish Association for Marine Science, Oban, UK
| | - Samuel A M Martin
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK
| | | | - David E K Ferrier
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK.
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3
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Rayamajhee B, Willcox M, Sharma S, Mooney R, Petsoglou C, Badenoch PR, Sherchan S, Henriquez FL, Carnt N. Zooming in on the intracellular microbiome composition of bacterivorous Acanthamoeba isolates. ISME COMMUNICATIONS 2024; 4:ycae016. [PMID: 38500701 PMCID: PMC10945361 DOI: 10.1093/ismeco/ycae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/29/2023] [Accepted: 01/22/2024] [Indexed: 03/20/2024]
Abstract
Acanthamoeba, a free-living amoeba in water and soil, is an emerging pathogen causing severe eye infection known as Acanthamoeba keratitis. In its natural environment, Acanthamoeba performs a dual function as an environmental heterotrophic predator and host for a range of microorganisms that resist digestion. Our objective was to characterize the intracellular microorganisms of phylogenetically distinct Acanthamoeba spp. isolated in Australia and India through directly sequencing 16S rRNA amplicons from the amoebae. The presence of intracellular bacteria was further confirmed by in situ hybridization and electron microscopy. Among the 51 isolates assessed, 41% harboured intracellular bacteria which were clustered into four major phyla: Pseudomonadota (previously known as Proteobacteria), Bacteroidota (previously known as Bacteroidetes), Actinomycetota (previously known as Actinobacteria), and Bacillota (previously known as Firmicutes). The linear discriminate analysis effect size analysis identified distinct microbial abundance patterns among the sample types; Pseudomonas species was abundant in Australian corneal isolates (P < 0.007), Enterobacteriales showed higher abundance in Indian corneal isolates (P < 0.017), and Bacteroidota was abundant in Australian water isolates (P < 0.019). The bacterial beta diversity of Acanthamoeba isolates from keratitis patients in India and Australia significantly differed (P < 0.05), while alpha diversity did not vary based on the country of origin or source of isolation (P > 0.05). More diverse intracellular bacteria were identified in water isolates as compared with clinical isolates. Confocal and electron microscopy confirmed the bacterial cells undergoing binary fission within the amoebal host, indicating the presence of viable bacteria. This study sheds light on the possibility of a sympatric lifestyle within Acanthamoeba, thereby emphasizing its crucial role as a bunker and carrier of potential human pathogens.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
| | - Savitri Sharma
- Jhaveri Microbiology Centre, Prof Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L. V. Prasad Eye Institute (LVPEI), Hyderabad, 500034, India
| | - Ronnie Mooney
- School of Health and Life Sciences, University of the West of Scotland, Blantyre, PA1 2BE, United Kingdom
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, South-Eastern Sydney Local Health District, Sydney, NSW 2000, Australia
- Save Sight Institute, University of Sydney, Sydney, NSW 2000, Australia
| | - Paul R Badenoch
- College of Medicine and Public Health, Flinders University, Adelaide, 5042, Australia
| | - Samendra Sherchan
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, United States
| | - Fiona L Henriquez
- School of Health and Life Sciences, University of the West of Scotland, Blantyre, PA1 2BE, United Kingdom
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
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Fatemi M, Niyyati M, Rouhani S, Karamati SA, Mirjalali H, Karanis P. Contamination of fresh vegetables in municipal stores with pathogenic Acanthamoeba genotypes; a public health concern. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2023; 33:1010-1021. [PMID: 35443833 DOI: 10.1080/09603123.2022.2067328] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/12/2022] [Indexed: 05/23/2023]
Abstract
Acanthamoeba spp. cause keratitis and encephalitis, and are a proper carrier of foodborne pathogens. A total of 70 samples including garden cress, chives, mint, parsley, and basil were collected. Samples were cultured onto a 2% non-nutrient agar medium. The cultures were analyzed using morphological and molecular techniques. In total, 18 (25.7%) out of 70 samples were positive including garden cress 10/22 (45.45%), chives 3/12 (25%), mint 2/13 (15.38%), basil 2/13 (15.38%), and parsley 1/10 (10%). The diagnostic fragment 3 was successfully sequenced in 15 samples and represented 11 (73.3%) T4, three (20%) T5, and one T9 genotypes. In addition, three, two, and one strains, belonging to the genotypes T4, T5, and T9 were ranked highly pathogenic. This is the first study reporting contamination of the most commonly consumed fresh vegetables with pathogenic Acanthamoeba genotypes. Our findings signify the public health concerns due the contamination of vegetables in municipal public markets.
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Affiliation(s)
- Marziye Fatemi
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Niyyati
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soheila Rouhani
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Ahmad Karamati
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamed Mirjalali
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Panagiotis Karanis
- University of Cologne, Medical Faculty and University Hospital, Cologne 50931, Germany
- Department of Basic and Clinical Sciences, Nicosia University Medical School, Nicosia, Cyprus
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The Status of Molecular Analyses of Isolates of Acanthamoeba Maintained by International Culture Collections. Microorganisms 2023; 11:microorganisms11020295. [PMID: 36838260 PMCID: PMC9961329 DOI: 10.3390/microorganisms11020295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/04/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Acanthamoeba is among the most ubiquitous protistan groups in nature. Knowledge of the biological diversity of Acanthamoeba comes in part from the use of strains maintained by the major microbial culture collections, ATCC and CCAP. Standard strains are vital to ensure the comparability of research. The diversity of standard strains of Acanthamoeba in the culture collections is reviewed, emphasizing the extent of genotypic studies based on DNA sequencing of the small subunit ribosomal RNA from the nucleus (18S rRNA gene; Rns) or the mitochondria (16S-like rRNA gene; rns). Over 170 different strains have been maintained at some time by culture centers. DNA sequence information is available for more than 70% of these strains. Determination of the genotypic classification of standard strains within the genus indicates that frequencies of types within culture collections only roughly mirror that from clinical or environmental studies, with significant differences in the frequency of some genotypes. Culture collections include the type of isolate from almost all named species of Acanthamoeba, allowing an evaluation of the validity of species designations. Multiple species are found to share the same Sequence Type, while multiple Sequence Types have been identified for different strains that share the same species name. Issues of sequence reliability and the possibility that a small number of standard strains have been mislabeled when studied are also examined, leading to potential problems for comparative analyses. It is important that all species have reliable genotype designations. The culture collections should be encouraged to assist in completing the molecular inventory of standard strains, while workers in the Acanthamoeba research community should endeavor to ensure that strains representative of genotypes that are missing from the culture collection are provided to the culture centers for preservation.
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Haselkorn TS, Jimenez D, Bashir U, Sallinger E, Queller DC, Strassmann JE, DiSalvo S. Novel Chlamydiae and Amoebophilus endosymbionts are prevalent in wild isolates of the model social amoeba Dictyostelium discoideum. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:708-719. [PMID: 34159734 PMCID: PMC8518690 DOI: 10.1111/1758-2229.12985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 06/12/2021] [Indexed: 05/24/2023]
Abstract
Amoebae interact with bacteria in multifaceted ways. Amoeba predation can serve as a selective pressure for the development of bacterial virulence traits. Bacteria may also adapt to life inside amoebae, resulting in symbiotic relationships. Indeed, particular lineages of obligate bacterial endosymbionts have been found in different amoebae. Here, we screened an extensive collection of Dictyostelium discoideum wild isolates for the presence of these bacterial symbionts using endosymbiont specific PCR primers. We find that these symbionts are surprisingly common, identified in 42% of screened isolates (N = 730). Members of the Chlamydiae phylum are particularly prevalent, occurring in 27% of the amoeba isolated. They are novel and phylogenetically distinct from other Chlamydiae. We also found Amoebophilus symbionts in 8% of screened isolates (N = 730). Antibiotic-cured amoebae behave similarly to their Chlamydiae or Amoebophilus-infected counterparts, suggesting that these endosymbionts do not significantly impact host fitness, at least in the laboratory. We found several natural isolates were co-infected with multiple endosymbionts, with no obvious fitness effect of co-infection under laboratory conditions. The high prevalence and novelty of amoeba endosymbiont clades in the model organism D. discoideum opens the door to future research on the significance and mechanisms of amoeba-symbiont interactions.
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Affiliation(s)
- Tamara S. Haselkorn
- Department of BiologyUniversity of Central Arkansas201 Donaghey Avenue, ConwayAR72035USA
| | - Daniela Jimenez
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Usman Bashir
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Eleni Sallinger
- Department of BiologyUniversity of Central Arkansas201 Donaghey Avenue, ConwayAR72035USA
| | - David C. Queller
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Joan E. Strassmann
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Susanne DiSalvo
- Department of Biological SciencesSouthern Illinois University Edwardsville44 Circle Drive, EdwardsvilleIL62026USA
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Amaro F, Martín-González A. Microbial warfare in the wild-the impact of protists on the evolution and virulence of bacterial pathogens. Int Microbiol 2021; 24:559-571. [PMID: 34365574 DOI: 10.1007/s10123-021-00192-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/03/2021] [Accepted: 06/28/2021] [Indexed: 01/01/2023]
Abstract
During the long history of co-evolution with protists, bacteria have evolved defense strategies to avoid grazing and survive phagocytosis. These mechanisms allow bacteria to exploit phagocytic cells as a protective niche in which to escape from environmental stress and even replicate. Importantly, these anti-grazing mechanisms can function as virulence factors when bacteria infect humans. Here, we discuss how protozoan predation exerts a selective pressure driving bacterial virulence and shaping their genomes, and how bacteria-protist interactions might contribute to the spread of antibiotic resistance as well. We provide examples to demonstrate that besides being voracious bacterial predators, protozoa can serve as melting pots where intracellular organisms exchange genetic information, or even "training grounds" where some pathogens become hypervirulent after passing through. In this special issue, we would like to emphasize the tremendous impact of bacteria-protist interactions on human health and the potential of amoebae as model systems to study biology and evolution of a variety of pathogens. Besides, a better understanding of bacteria-protist relationships will help us expand our current understanding of bacterial virulence and, likely, how pathogens emerge.
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Affiliation(s)
- Francisco Amaro
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain.
| | - Ana Martín-González
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain
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Rayamajhee B, Subedi D, Peguda HK, Willcox MD, Henriquez FL, Carnt N. A Systematic Review of Intracellular Microorganisms within Acanthamoeba to Understand Potential Impact for Infection. Pathogens 2021; 10:pathogens10020225. [PMID: 33670718 PMCID: PMC7922382 DOI: 10.3390/pathogens10020225] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/20/2022] Open
Abstract
Acanthamoeba, an opportunistic pathogen is known to cause an infection of the cornea, central nervous system, and skin. Acanthamoeba feeds different microorganisms, including potentially pathogenic prokaryotes; some of microbes have developed ways of surviving intracellularly and this may mean that Acanthamoeba acts as incubator of important pathogens. A systematic review of the literature was performed in order to capture a comprehensive picture of the variety of microbial species identified within Acanthamoeba following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Forty-three studies met the inclusion criteria, 26 studies (60.5%) examined environmental samples, eight (18.6%) studies examined clinical specimens, and another nine (20.9%) studies analysed both types of samples. Polymerase chain reaction (PCR) followed by gene sequencing was the most common technique used to identify the intracellular microorganisms. Important pathogenic bacteria, such as E. coli, Mycobacterium spp. and P. aeruginosa, were observed in clinical isolates of Acanthamoeba, whereas Legionella, adenovirus, mimivirus, and unidentified bacteria (Candidatus) were often identified in environmental Acanthamoeba. Increasing resistance of Acanthamoeba associated intracellular pathogens to antimicrobials is an increased risk to public health. Molecular-based future studies are needed in order to assess the microbiome residing in Acanthamoeba, as a research on the hypotheses that intracellular microbes can affect the pathogenicity of Acanthamoeba infections.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
- Department of Infection and Immunology, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur 44700, Nepal
- Correspondence: or
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia;
| | - Hari Kumar Peguda
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
| | - Mark Duncan Willcox
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
| | - 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, UK;
| | - Nicole Carnt
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
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Paranjape K, Bédard É, Shetty D, Hu M, Choon FCP, Prévost M, Faucher SP. Unravelling the importance of the eukaryotic and bacterial communities and their relationship with Legionella spp. ecology in cooling towers: a complex network. MICROBIOME 2020; 8:157. [PMID: 33183356 PMCID: PMC7664032 DOI: 10.1186/s40168-020-00926-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/20/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Cooling towers are a major source of large community-associated outbreaks of Legionnaires' disease, a severe pneumonia. This disease is contracted when inhaling aerosols that are contaminated with bacteria from the genus Legionella, most importantly Legionella pneumophila. How cooling towers support the growth of this bacterium is still not well understood. As Legionella species are intracellular parasites of protozoa, it is assumed that protozoan community in cooling towers play an important role in Legionella ecology and outbreaks. However, the exact mechanism of how the eukaryotic community contributes to Legionella ecology is still unclear. Therefore, we used 18S rRNA gene amplicon sequencing to characterize the eukaryotic communities of 18 different cooling towers. The data from the eukaryotic community was then analysed with the bacterial community of the same towers in order to understand how each community could affect Legionella spp. ecology in cooling towers. RESULTS We identified several microbial groups in the cooling tower ecosystem associated with Legionella spp. that suggest the presence of a microbial loop in these systems. Dissolved organic carbon was shown to be a major factor in shaping the eukaryotic community and may be an important factor for Legionella ecology. Network analysis, based on co-occurrence, revealed that Legionella was correlated with a number of different organisms. Out of these, the bacterial genus Brevundimonas and the ciliate class Oligohymenophorea were shown, through in vitro experiments, to stimulate the growth of L. pneumophila through direct and indirect mechanisms. CONCLUSION Our results suggest that Legionella ecology depends on the host community, including ciliates and on several groups of organisms that contribute to its survival and growth in the cooling tower ecosystem. These findings further support the idea that some cooling tower microbiomes may promote the survival and growth of Legionella better than others. Video Abstract.
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Affiliation(s)
- Kiran Paranjape
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Émilie Bédard
- Department of Civil Engineering, Polytechnique Montreal, Montréal, QC, Canada
| | - Deeksha Shetty
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Mengqi Hu
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Fiona Chan Pak Choon
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montreal, Montréal, QC, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada.
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Akter S, Shazib SUA, Shin MK. Segnochrobactrum spirostomi gen. nov., sp. nov., isolated from the ciliate Spirostomum yagiui and description of a novel family, Segnochrobactraceae fam. nov. within the order Rhizobiales of the class Alphaproteobacteria. Int J Syst Evol Microbiol 2019; 70:1250-1258. [PMID: 31800387 PMCID: PMC7397251 DOI: 10.1099/ijsem.0.003907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A bacterial strain, designated Sp-1T, was isolated from the heterotrich ciliate Spirostomum yagiui collected from a reservoir located in Ulsan, Republic of Korea. Cells of Sp-1T were Gram stain-negative, rod-shaped, non-spore-forming, non-motile and contained poly-β-hydroxybutyrate granules. Phylogenetic analyses based on 16S rRNA gene sequences indicated that Sp-1T constituted a distinct phylogenetic lineage within different families in the order Rhizobiales with a pairwise sequence similarity of 95 % to the species of the genus Ochrobactrum: Ochrobactrum anthropi ATCC 49188T and Ochrobactrum cytisi ESC1T (family Brucellaceae). The major cellular fatty acids were C19 : 0 cyclo ω8c (44.4 %) and C16 : 0 (32.1 %). The identified sole isoprenoid quinone was ubiquinone-10 (Q-10). The major polar lipids produced were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid, two unidentified phospholipids and three unidentified lipids. The genome size was about 5.4 Mbp and the DNA G+C content was 68.2 mol%. Sp-1T exhibited the highest average nucleotide identity value of 76.6 % and in silico DNA–DNA hybridization value of 22.1 % with Pseudoxanthobacter soli DSM 19599T (family Xanthobacteraeae). This strain is distinguishable from closely related members of the order Rhizobiales by its differential phenotypic, chemotaxonomic, genomic and phylogenetic characteristics. On the basis of evidence from polyphasic taxonomic analysis, we concluded that Sp-1T represents a novel species in a novel genus within the order Rhizobiales, for which the name Segnochrobactrum spirostomi gen. nov., sp. nov. is proposed. The type strain is Sp-1T (=KCTC 62036T=JCM 32162T). We also describe a novel family, Segnochrobactraceae fam. nov., to encompass the proposed novel genus and species.
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Affiliation(s)
- Sumi Akter
- Department of Botany, Jagannath University, Dhaka 1100, Bangladesh.,Department of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea
| | | | - Mann Kyoon Shin
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea
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11
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Okubo T, Matsushita M, Nakamura S, Matsuo J, Nagai H, Yamaguchi H. Acanthamoeba S13WT relies on its bacterial endosymbiont to backpack human pathogenic bacteria and resist Legionella infection on solid media. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:344-354. [PMID: 29611898 DOI: 10.1111/1758-2229.12645] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Soil-borne amoeba Acanthamoeba S13WT has an endosymbiotic relationship with an environmental Neochlamydia bacterial strain. However, regardless of extensive experiments in liquid media, the biological advantage of the symbiosis remained elusive. We therefore explored the role of the endosymbiont in predator-prey interactions on solid media. A mixed culture of the symbiotic or aposymbiotic amoebae and GFP-expressing Escherichia coli or Salmonella Enteritidis was spotted onto the centre of a LB or B-CYE agar plate preinoculated with a ring of mCherry-expressing Legionella pneumophila (Legionella 'wall'). The spread of the amoebae on the plate was assessed using a fluorescence imaging system or scanning electron microscopy. As a result, in contrast to the aposymbiotic amoebae, the symbiotic amoebae backpacked these GFP-expressing bacteria and formed flower-like fluorescence patterns in an anticlockwise direction. Other bacteria (Pseudomonas aeruginosa and Stenotrophomonas maltophilia), but not Staphylococcus aureus, were also backpacked by the symbiotic amoebae on LB agar, although lacked the movement to anticlockwise direction. Furthermore, in contrast to the aposymbiotic amoebae, the symbiotic amoebae backpacking the E. coli broke through the Legionella 'wall' on B-CYE agar plates. Thus, we concluded that Acanthamoeba S13WT required the Neochlamydia endosymbiont to backpack human pathogenic bacteria and resist Legionella infection on solid agar.
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Affiliation(s)
- Torahiko Okubo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Mizue Matsushita
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Shinji Nakamura
- Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Junji Matsuo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroki Nagai
- Department of Microbiology, Gifu University School of Medicine, Yanagido 1-1, Gifu, Gifu 501-1194, Japan
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
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12
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Purssell A, Lau R, Boggild AK. Azithromycin and Doxycycline Attenuation of Acanthamoeba Virulence in a Human Corneal Tissue Model. J Infect Dis 2017; 215:1303-1311. [PMID: 27578848 DOI: 10.1093/infdis/jiw410] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 08/15/2016] [Indexed: 01/31/2023] Open
Abstract
Background Amoebic keratitis is a potentially blinding eye infection caused by ubiquitous, free-living, environmental acanthamoebae, which are known to harbor bacterial endosymbionts. A Chlamydia-like endosymbiont has previously enhanced Acanthamoeba virulence in vitro. We investigated the potential effect of Acanthamoeba-endosymbiont coinfection in a human corneal tissue model representing clinical amoebic keratitis infection. Methods Environmental and corneal Acanthamoeba isolates from the American Type Culture Collection were screened for endosymbionts by amplifying and sequencing bacterial 16S as well as Chlamydiales-specific DNA. Each Acanthamoeba isolate was used to infect EpiCorneal cells, a 3-dimensional human corneal tissue model. EpiCorneal cells were then treated with azithromycin, doxycycline, or control medium to determine whether antibiotics targeting common classes of bacterial endosymbionts attenuated Acanthamoeba virulence, as indicated by decreased observed cytopathic effect and inflammatory biomarker production. Results A novel endosymbiont closely related to Mycobacterium spp. was identified in Acanthamoeba polyphaga 50495. Infection of EpiCorneal cells with Acanthamoeba castellanii 50493 and A. polyphaga 50372 led to increased production of inflammatory cytokines and cytopathic effects visible under microscopy. These increases were attenuated by azithromycin and doxycycline. Conclusions Our findings suggest that azithromycin and doxycycline may be effective adjuvants to standard antiacanthamoebal chemotherapy by potentially abrogating virulence-enhancing properties of bacterial endosymbionts.
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Affiliation(s)
- Andrew Purssell
- Faculty of Medicine, University of British Columbia, Vancouver
| | | | - Andrea K Boggild
- Public Health Ontario Laboratories.,Tropical Disease Unit, Toronto General Hospital.,Department of Medicine, University of Toronto, Ontario, Canada
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Free-Living Amoebae as Hosts for and Vectors of Intracellular Microorganisms with Public Health Significance. Viruses 2017; 9:v9040065. [PMID: 28368313 PMCID: PMC5408671 DOI: 10.3390/v9040065] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 03/24/2017] [Indexed: 12/14/2022] Open
Abstract
Free-living amoebae (FLA) are parasites within both humans and animals causing a wide range of symptoms and act as hosts of, and vehicles for phylogenetically diverse microorganisms, called endocytobionts. The interaction of the FLA with sympatric microorganisms leads to an exceptional diversity within FLA. Some of these bacteria, viruses, and even eukaryotes, can live and replicate intracellularly within the FLA. This relationship provides protection to the microorganisms from external interventions and a dispersal mechanism across various habitats. Among those intracellularly-replicating or -residing organisms there are obligate and facultative pathogenic microorganisms affecting the health of humans or animals and are therefore of interest to Public Health Authorities. Mimiviruses, Pandoraviruses, and Pithoviruses are examples for interesting viral endocytobionts within FLA. Future research is expected to reveal further endocytobionts within free-living amoebae and other protozoa through co-cultivation studies, genomic, transcriptomic, and proteomic analyses.
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14
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Müller A, Walochnik J, Wagner M, Schmitz-Esser S. A clinical Acanthamoeba isolate harboring two distinct bacterial endosymbionts. Eur J Protistol 2016; 56:21-25. [DOI: 10.1016/j.ejop.2016.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 01/09/2023]
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15
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Qi W, Vaughan L, Katharios P, Schlapbach R, Seth-Smith HMB. Host-Associated Genomic Features of the Novel Uncultured Intracellular Pathogen Ca. Ichthyocystis Revealed by Direct Sequencing of Epitheliocysts. Genome Biol Evol 2016; 8:1672-89. [PMID: 27190004 PMCID: PMC4943182 DOI: 10.1093/gbe/evw111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2016] [Indexed: 12/24/2022] Open
Abstract
Advances in single-cell and mini-metagenome sequencing have enabled important investigations into uncultured bacteria. In this study, we applied the mini-metagenome sequencing method to assemble genome drafts of the uncultured causative agents of epitheliocystis, an emerging infectious disease in the Mediterranean aquaculture species gilthead seabream. We sequenced multiple cyst samples and constructed 11 genome drafts from a novel beta-proteobacterial lineage, Candidatus Ichthyocystis. The draft genomes demonstrate features typical of pathogenic bacteria with an obligate intracellular lifestyle: a reduced genome of up to 2.6 Mb, reduced G + C content, and reduced metabolic capacity. Reconstruction of metabolic pathways reveals that Ca Ichthyocystis genomes lack all amino acid synthesis pathways, compelling them to scavenge from the fish host. All genomes encode type II, III, and IV secretion systems, a large repertoire of predicted effectors, and a type IV pilus. These are all considered to be virulence factors, required for adherence, invasion, and host manipulation. However, no evidence of lipopolysaccharide synthesis could be found. Beyond the core functions shared within the genus, alignments showed distinction into different species, characterized by alternative large gene families. These comprise up to a third of each genome, appear to have arisen through duplication and diversification, encode many effector proteins, and are seemingly critical for virulence. Thus, Ca Ichthyocystis represents a novel obligatory intracellular pathogenic beta-proteobacterial lineage. The methods used: mini-metagenome analysis and manual annotation, have generated important insights into the lifestyle and evolution of the novel, uncultured pathogens, elucidating many putative virulence factors including an unprecedented array of novel gene families.
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Affiliation(s)
- Weihong Qi
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Lloyd Vaughan
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
| | - Pantelis Katharios
- Hellenic Center for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, Heraklion, Greece
| | - Ralph Schlapbach
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Helena M B Seth-Smith
- Functional Genomics Center Zurich, University of Zurich, Switzerland Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
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Maschio VJ, Corção G, Bücker F, Caumo K, Rott MB. Identification of Paenibacillus as a Symbiont in Acanthamoeba. Curr Microbiol 2015; 71:415-20. [DOI: 10.1007/s00284-015-0869-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/26/2015] [Indexed: 11/29/2022]
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17
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Lagkouvardos I, Shen J, Horn M. Improved axenization method reveals complexity of symbiotic associations between bacteria and acanthamoebae. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:383-388. [PMID: 24992537 DOI: 10.1111/1758-2229.12162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/30/2014] [Indexed: 06/03/2023]
Abstract
Bacteria associated with free-living amoebae have attracted considerable attention because of their role in human disease and as models for studying endosymbiosis. However, the identification and analysis of such novel associations are hindered by the limitations of methods for isolation and axenization of amoebae. Here, we replaced the heat-inactivated Escherichia coli, which is typically used as food source during axenization, with a live E. coli tolC knockout mutant strain hypersensitive to antibiotics. Together with the addition of otherwise sublethal amounts of ampicillin, this approach tripled the success rate and reduced the time required for axenization by at least 3 days. Using this method for two environmental samples, 10 Acanthamoeba strains were isolated, seven of which contained bacterial symbionts. In three cases, amoebae harbouring two phylogenetically distinct symbionts were recovered, supporting a more widespread occurrence of multi-partner symbiotic associations among free-living amoebae.
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Affiliation(s)
- Ilias Lagkouvardos
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
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18
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Domman D, Collingro A, Lagkouvardos I, Gehre L, Weinmaier T, Rattei T, Subtil A, Horn M. Massive expansion of Ubiquitination-related gene families within the Chlamydiae. Mol Biol Evol 2014; 31:2890-904. [PMID: 25069652 PMCID: PMC4209131 DOI: 10.1093/molbev/msu227] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Gene loss, gain, and transfer play an important role in shaping the genomes of all organisms; however, the interplay of these processes in isolated populations, such as in obligate intracellular bacteria, is less understood. Despite a general trend towards genome reduction in these microbes, our phylogenomic analysis of the phylum Chlamydiae revealed that within the family Parachlamydiaceae, gene family expansions have had pronounced effects on gene content. We discovered that the largest gene families within the phylum are the result of rapid gene birth-and-death evolution. These large gene families are comprised of members harboring eukaryotic-like ubiquitination-related domains, such as F-box and BTB-box domains, marking the largest reservoir of these proteins found among bacteria. A heterologous type III secretion system assay suggests that these proteins function as effectors manipulating the host cell. The large disparity in copy number of members in these families between closely related organisms suggests that nonadaptive processes might contribute to the evolution of these gene families. Gene birth-and-death evolution in concert with genomic drift might represent a previously undescribed mechanism by which isolated bacterial populations diversify.
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Affiliation(s)
- Daryl Domman
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Astrid Collingro
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Ilias Lagkouvardos
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Lena Gehre
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France
| | - Thomas Weinmaier
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Thomas Rattei
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Agathe Subtil
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
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Scheid P. Relevance of free-living amoebae as hosts for phylogenetically diverse microorganisms. Parasitol Res 2014; 113:2407-14. [PMID: 24828345 DOI: 10.1007/s00436-014-3932-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/30/2014] [Indexed: 10/25/2022]
Abstract
In addition to their role as parasites, free-living amoebae (FLA) can act as hosts of and vehicles for phylogentically diverse microorganisms while some of them replicate intracellularly. These microorganisms are adapted to the intracellular conditions in the amoeba, find suitable conditions and protection from negative environmental influences and take advantage of the dispersal in the environment by their amoebic host. It is expedient to call these organisms "endocytobionts", at least during the initial steps of any studies. By doing so, it is not necessary to go into potential characteristics of these relationships such as parasitism, phoresy, zoochory, or mutualism at an early stage of study. Among those organisms resisting the lysis within their amoebic host, there are obligate and facultative pathogenic microorganisms affecting the health of humans or animals. FLA-endocytobiont relationships are not only important for the tenacity of the involved microorganisms. Especially if FLA are present in biofilms and there are close ties with many other microorganisms, the odds are for some of these microorganisms to develop human pathogenic properties. Here, the amoebic passage seems to be a prerequisite for the development of virulence factors and it may have an impact on evolutionary processes.
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Affiliation(s)
- Patrick Scheid
- Central Institute of the Bundeswehr Medical Service Koblenz, Koblenz, Germany,
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20
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Subtil A, Collingro A, Horn M. Tracing the primordial Chlamydiae: extinct parasites of plants? TRENDS IN PLANT SCIENCE 2014; 19:36-43. [PMID: 24210739 DOI: 10.1016/j.tplants.2013.10.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/09/2013] [Accepted: 10/15/2013] [Indexed: 06/02/2023]
Abstract
Chlamydiae are obligate intracellular bacteria found as symbionts and pathogens in a wide range of eukaryotes, including protists, invertebrates, and vertebrates. It was recently proposed that an ancient chlamydial symbiont facilitated the establishment of primary plastids in a tripartite symbiosis with cyanobacteria and early eukaryotes. In this review, we summarize recent advances in understanding of the lifestyle and the evolutionary history of extant Chlamydiae. We reconstruct and describe key features of the ancient chlamydial symbiont. We propose that it was already adapted to an intracellular lifestyle before the emergence of Archaeplastida, and that several observations are compatible with an essential contribution of Chlamydiae to the evolution of algae and plants.
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Affiliation(s)
- Agathe Subtil
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France; CNRS URA2582, Paris, France.
| | - Astrid Collingro
- University of Vienna, Division of Microbial Ecology, Vienna, Austria
| | - Matthias Horn
- University of Vienna, Division of Microbial Ecology, Vienna, Austria
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21
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Alves JMP, Klein CC, da Silva FM, Costa-Martins AG, Serrano MG, Buck GA, Vasconcelos ATR, Sagot MF, Teixeira MMG, Motta MCM, Camargo EP. Endosymbiosis in trypanosomatids: the genomic cooperation between bacterium and host in the synthesis of essential amino acids is heavily influenced by multiple horizontal gene transfers. BMC Evol Biol 2013; 13:190. [PMID: 24015778 PMCID: PMC3846528 DOI: 10.1186/1471-2148-13-190] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/06/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trypanosomatids of the genera Angomonas and Strigomonas live in a mutualistic association characterized by extensive metabolic cooperation with obligate endosymbiotic Betaproteobacteria. However, the role played by the symbiont has been more guessed by indirect means than evidenced. Symbiont-harboring trypanosomatids, in contrast to their counterparts lacking symbionts, exhibit lower nutritional requirements and are autotrophic for essential amino acids. To evidence the symbiont's contributions to this autotrophy, entire genomes of symbionts and trypanosomatids with and without symbionts were sequenced here. RESULTS Analyses of the essential amino acid pathways revealed that most biosynthetic routes are in the symbiont genome. By contrast, the host trypanosomatid genome contains fewer genes, about half of which originated from different bacterial groups, perhaps only one of which (ornithine cyclodeaminase, EC:4.3.1.12) derived from the symbiont. Nutritional, enzymatic, and genomic data were jointly analyzed to construct an integrated view of essential amino acid metabolism in symbiont-harboring trypanosomatids. This comprehensive analysis showed perfect concordance among all these data, and revealed that the symbiont contains genes for enzymes that complete essential biosynthetic routes for the host amino acid production, thus explaining the low requirement for these elements in symbiont-harboring trypanosomatids. Phylogenetic analyses show that the cooperation between symbionts and their hosts is complemented by multiple horizontal gene transfers, from bacterial lineages to trypanosomatids, that occurred several times in the course of their evolution. Transfers occur preferentially in parts of the pathways that are missing from other eukaryotes. CONCLUSION We have herein uncovered the genetic and evolutionary bases of essential amino acid biosynthesis in several trypanosomatids with and without endosymbionts, explaining and complementing decades of experimental results. We uncovered the remarkable plasticity in essential amino acid biosynthesis pathway evolution in these protozoans, demonstrating heavy influence of horizontal gene transfer events, from Bacteria to trypanosomatid nuclei, in the evolution of these pathways.
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Schmitz-Esser S, Penz T, Spang A, Horn M. A bacterial genome in transition--an exceptional enrichment of IS elements but lack of evidence for recent transposition in the symbiont Amoebophilus asiaticus. BMC Evol Biol 2011; 11:270. [PMID: 21943072 PMCID: PMC3196728 DOI: 10.1186/1471-2148-11-270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/26/2011] [Indexed: 11/18/2022] Open
Abstract
Background Insertion sequence (IS) elements are important mediators of genome plasticity and are widespread among bacterial and archaeal genomes. The 1.88 Mbp genome of the obligate intracellular amoeba symbiont Amoebophilus asiaticus contains an unusually large number of transposase genes (n = 354; 23% of all genes). Results The transposase genes in the A. asiaticus genome can be assigned to 16 different IS elements termed ISCaa1 to ISCaa16, which are represented by 2 to 24 full-length copies, respectively. Despite this high IS element load, the A. asiaticus genome displays a GC skew pattern typical for most bacterial genomes, indicating that no major rearrangements have occurred recently. Additionally, the high sequence divergence of some IS elements, the high number of truncated IS element copies (n = 143), as well as the absence of direct repeats in most IS elements suggest that the IS elements of A. asiaticus are transpositionally inactive. Although we could show transcription of 13 IS elements, we did not find experimental evidence for transpositional activity, corroborating our results from sequence analyses. However, we detected contiguous transcripts between IS elements and their downstream genes at nine loci in the A. asiaticus genome, indicating that some IS elements influence the transcription of downstream genes, some of which might be important for host cell interaction. Conclusions Taken together, the IS elements in the A. asiaticus genome are currently in the process of degradation and largely represent reflections of the evolutionary past of A. asiaticus in which its genome was shaped by their activity.
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Affiliation(s)
- Stephan Schmitz-Esser
- Department of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
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23
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Anacarso I, de Niederhäusern S, Messi P, Guerrieri E, Iseppi R, Sabia C, Bondi M. Acanthamoeba polyphaga, a potential environmental vector for the transmission of food-borne and opportunistic pathogens. J Basic Microbiol 2011; 52:261-8. [PMID: 21953544 DOI: 10.1002/jobm.201100097] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 07/15/2011] [Indexed: 11/06/2022]
Abstract
The endosymbiotic relationship could represent for many bacteria an important condition favouring their spread in the environment and in foods. For this purpose we studied the behaviour of some food-borne and opportunistic pathogens (Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Salmonella enterica serovar Enteritidis, Aeromonas hydrophila, Yersinia enterocolitica) when internalized in Acanthamoeba polyphaga. Our results confirm the capability of the bacteria tested to grow within amoebal hosts. We can observe two types of interactions of the bacteria internalized in A. polyphaga. The first type, showed by Y. enterocolitica and A. hydrophila, was characterized by an early replication, probably followed by the killing and digestion of the bacteria. The second type, showed by E. faecalis and S. aureus was characterized by the persistence and grow inside the host without lysis. Lastly, when amoebae were co-cultured with L. monocytogenes and S. Enteritidis, an eclipse phase followed by an active intracellular growth was observed, suggesting a third type of predator-prey trend. The extracellular count in presence of A. polyphaga, as a result of an intracellular multiplication and subsequent release, was characterized by an increase of E. faecalis, S. aureus, L. monocytogenes and S. Enteritidis, and by a low or absent cell count for Y. enterocolitica and A. hydrophila. Our study suggests that the investigated food-borne and opportunistic pathogens are, in most cases, able to interact with A. polyphaga, to intracellularly replicate and, lastly, to be potentially spread in the environment, underlining the possible role of this protozoan in food contamination.
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Affiliation(s)
- Immacolata Anacarso
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
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24
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Teixeira MMG, Borghesan TC, Ferreira RC, Santos MA, Takata CSA, Campaner M, Nunes VLB, Milder RV, de Souza W, Camargo EP. Phylogenetic validation of the genera Angomonas and Strigomonas of trypanosomatids harboring bacterial endosymbionts with the description of new species of trypanosomatids and of proteobacterial symbionts. Protist 2011; 162:503-24. [PMID: 21420905 DOI: 10.1016/j.protis.2011.01.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 01/12/2011] [Indexed: 11/30/2022]
Abstract
We comparatively examined the nutritional, molecular and optical and electron microscopical characteristics of reference species and new isolates of trypanosomatids harboring bacterial endosymbionts. Sequencing of the V7V8 region of the small subunit of the ribosomal RNA (SSU rRNA) gene distinguished six major genotypes among the 13 isolates examined. The entire sequences of the SSU rRNA and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) genes were obtained for phylogenetic analyses. In the resulting phylogenetic trees, the symbiont-harboring species clustered as a major clade comprising two subclades that corresponded to the proposed genera Angomonas and Strigomonas. The genus Angomonas comprised 10 flagellates including former Crithidia deanei and C. desouzai plus a new species. The genus Strigomonas included former Crithidia oncopelti and Blastocrithidia culicis plus a new species. Sequences from the internal transcribed spacer of ribosomal DNA (ITS rDNA) and size polymorphism of kinetoplast DNA (kDNA) minicircles revealed considerable genetic heterogeneity within the genera Angomonas and Strigomonas. Phylogenetic analyses based on 16S rDNA and ITS rDNA sequences demonstrated that all of the endosymbionts belonged to the Betaproteobacteria and revealed three new species. The congruence of the phylogenetic trees of trypanosomatids and their symbionts support a co-divergent host-symbiont evolutionary history.
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Affiliation(s)
- Marta M G Teixeira
- Department of Parasitology, ICB, University of São Paulo (USP), São Paulo, 05508-000, SP, Brazil.
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Coscollá M, Comas I, González-Candelas F. Quantifying Nonvertical Inheritance in the Evolution of Legionella pneumophila. Mol Biol Evol 2010; 28:985-1001. [PMID: 20961962 DOI: 10.1093/molbev/msq278] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Mireia Coscollá
- Unidad Mixta de Investigación Genómica y Salud CSISP-UV/Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Valencia, Spain
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Glaser KC, Hetrick ND, Molestina RE. Evidence for a previously unrecognized mycobacterial endosymbiont in Acanthamoeba castellanii strain Ma (ATCC ® 50370 ™). J Eukaryot Microbiol 2010; 58:75-6. [PMID: 21182562 DOI: 10.1111/j.1550-7408.2010.00513.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the isolation of a mycobacterium from Acanthamoeba castellanii strain Ma (ATCC(®) 50370(™)). The mycobacterium resides within vacuoles of A. castellanii, can be cultured by routine methodologies, and is a member of the Mycobacterium avium complex. Previously unrecognized mycobacterial endosymbionts are likely common among strains of Acanthamoeba housed at culture collections.
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Affiliation(s)
- Kathleen C Glaser
- Protistology Department, American Type Culture Collection, Manassas, Virginia 20110, USA
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Mycobacterium avium infections of Acanthamoeba strains: host strain variability, grazing-acquired infections, and altered dynamics of inactivation with monochloramine. Appl Environ Microbiol 2010; 76:6685-8. [PMID: 20709834 DOI: 10.1128/aem.00644-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stable Mycobacterium avium infections of several Acanthamoeba strains were characterized by increased infection resistance of recent environmental isolates and reduced infectivity in the presence of other bacteria. Exposure of M. avium in coculture with Acanthamoeba castellanii to monochloramine yielded inactivation kinetics markedly similar to those observed for A. castellanii alone.
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Nakamura S, Matsuo J, Hayashi Y, Kawaguchi K, Yoshida M, Takahashi K, Mizutani Y, Yao T, Yamaguchi H. Endosymbiotic bacterium Protochlamydia can survive in acanthamoebae following encystation. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:611-618. [PMID: 23766232 DOI: 10.1111/j.1758-2229.2010.00182.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Obligate intracellular bacteria are commonly seen as endosymbionts of acanthamoebae. However, whether endosymbionts can survive amoebal encystations remains a significant challenge in cellular biology. The survival of the endosymbiotic bacteria Protochlamydia belonging to environmental chlamydiae found in an amoebal isolate that we have previously reported (Environmental Microbiology Reports, DOI: 10.1111/j.1758-2229.2009.00094.x, 2009) following encystation was therefore assessed. The bacteria were observed in cysts and trophozoites reverted from cysts by analysis with transmission electron microscope, and the bacterial 16S rRNA transcripts were detected in amoeba cultures following encystations by reverse transcription polymerase chain reaction method. Furthermore, the bacterial growth was also confirmed, by fluorescent in situ hybridization analysis and the AIU assay that we have previously established (Applied Environmental Microbiology, 74: 6397-6404, 2008), in trophozoites reverted from cysts stored at 4°C for up to a month after encystation. Thus, these results demonstrated that Protochlamydia could survive in acanthamoebae following encystation. Our findings suggest that amoeba cysts might be further studied in order to understand their role in the environmental survival of endosymbionts.
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Affiliation(s)
- Shinji Nakamura
- Division of Biomedical Imaging Research, Division of Ultrastructural Research, and Department of Human Pathology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan. Department of Medical Laboratory Sciences, Hokkaido University Graduate School of Health Sciences, Sapporo, Hokkaido 060-0812, Japan
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Matsuo J, Kawaguchi K, Nakamura S, Hayashi Y, Yoshida M, Takahashi K, Mizutani Y, Yao T, Yamaguchi H. Survival and transfer ability of phylogenetically diverse bacterial endosymbionts in environmental Acanthamoeba isolates. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:524-533. [PMID: 23766223 DOI: 10.1111/j.1758-2229.2009.00094.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Obligate intracellular bacteria are commonly found as endosymbionts of acanthamoebae; however, their survival in and ability to transfer to amoebae are currently uncharacterized. In this study, six bacterial endosymbionts, found in five environmental Acanthamoeba isolates (S13, R18, S23, S31, S40) from different locations of Sapporo city, Japan, were characterized. Phylogenetic analysis revealed that three bacterial endosymbionts (eS23, eS31, eS40a) belonged to α- and β-Proteobacteria phyla and the remaining endosymbionts (eS13, eR18, eS40b) belonged to the order Chlamydiales. The Acanthamoeba isolate (S40) contained two phylogenetically different bacterial endosymbionts (eS40a, eS40b). Fluorescent in situ hybridization analysis showed that all bacterial endosymbionts were diffusely localized within amoebae. Transmission electron microscopy also showed that the endosymbionts were rod-shaped (eS23, eS31, eS40a) or sphere- or crescent-shaped (eS13, eR18, eS40b). No successful culture of these bacteria was achieved using conventional culture methods, but the viability of endosymbionts was confirmed by live/dead staining and RT-PCR methods. However, endosymbionts (except eR18) derived from original host cells lost the ability to be transferred to another Acanthamoebae strains [ATCC strain (C3), environmental strains (S14, R23, S24)]. Thus, our data demonstrate that phylogenetically diverse bacterial endosymbionts found in amoebae maintain a stable interaction with amoebae, but the transferability is limited.
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Affiliation(s)
- Junji Matsuo
- Department of Medical Laboratory Sciences, Hokkaido University Graduate School of Health Sciences, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan. Division of Biomedical Imaging Research, Division of Ultrastructural Research, and Department of Human Pathology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
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Thomas V, McDonnell G, Denyer SP, Maillard JY. Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality. FEMS Microbiol Rev 2010; 34:231-59. [DOI: 10.1111/j.1574-6976.2009.00190.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Saccamoeba lacustris, sp. nov. (Amoebozoa: Lobosea: Hartmannellidae), a new lobose amoeba, parasitized by the novel chlamydia 'Candidatus Metachlamydia lacustris' (Chlamydiae: Parachlamydiaceae). Eur J Protistol 2010; 46:86-95. [PMID: 20347279 DOI: 10.1016/j.ejop.2009.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 09/22/2009] [Accepted: 10/22/2009] [Indexed: 11/24/2022]
Abstract
An amoeba isolated from an aquatic biotope, identified morphologically as Saccamoeba limax, was found harbouring mutualistic rod-shaped gram-negative bacteria. During their cultivation on agar plates, a coinfection also by lysis-inducing chlamydia-like organisms was found in some subpopulations of that amoeba. .Here we provide a molecular-based identification of both the amoeba host and the two bacterial endosymbionts. Analysis of the 18S rRNA gene revealed that this strain is the sister-group to Glaeseria, for which we proposed the name Saccamoeba lacustris. The rod-shaped endosymbiont was identified as a member of Variovorax paradoxus group (Comamonadaceae, Beta-Proteobacteria). No growth on bacteriological agars was recorded, hence this symbiont might be strictly intracellular. The chlamydia-like parasite was unable to infect Acanthamoeba and other amoebae in coculture, showing high host specificity. Phylogenetic analysis based on the 16S rDNA indicated that it is a new member of the family Parachlamydiaceae (order Chlamydiales), for which we proposed the name 'Candidatus Metachlamydia lacustris'.
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Schmitz-Esser S, Tischler P, Arnold R, Montanaro J, Wagner M, Rattei T, Horn M. The genome of the amoeba symbiont "Candidatus Amoebophilus asiaticus" reveals common mechanisms for host cell interaction among amoeba-associated bacteria. J Bacteriol 2010; 192:1045-57. [PMID: 20023027 PMCID: PMC2812958 DOI: 10.1128/jb.01379-09] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/07/2009] [Indexed: 11/20/2022] Open
Abstract
Protozoa play host for many intracellular bacteria and are important for the adaptation of pathogenic bacteria to eukaryotic cells. We analyzed the genome sequence of "Candidatus Amoebophilus asiaticus," an obligate intracellular amoeba symbiont belonging to the Bacteroidetes. The genome has a size of 1.89 Mbp, encodes 1,557 proteins, and shows massive proliferation of IS elements (24% of all genes), although the genome seems to be evolutionarily relatively stable. The genome does not encode pathways for de novo biosynthesis of cofactors, nucleotides, and almost all amino acids. "Ca. Amoebophilus asiaticus" encodes a variety of proteins with predicted importance for host cell interaction; in particular, an arsenal of proteins with eukaryotic domains, including ankyrin-, TPR/SEL1-, and leucine-rich repeats, which is hitherto unmatched among prokaryotes, is remarkable. Unexpectedly, 26 proteins that can interfere with the host ubiquitin system were identified in the genome. These proteins include F- and U-box domain proteins and two ubiquitin-specific proteases of the CA clan C19 family, representing the first prokaryotic members of this protein family. Consequently, interference with the host ubiquitin system is an important host cell interaction mechanism of "Ca. Amoebophilus asiaticus". More generally, we show that the eukaryotic domains identified in "Ca. Amoebophilus asiaticus" are also significantly enriched in the genomes of other amoeba-associated bacteria (including chlamydiae, Legionella pneumophila, Rickettsia bellii, Francisella tularensis, and Mycobacterium avium). This indicates that phylogenetically and ecologically diverse bacteria which thrive inside amoebae exploit common mechanisms for interaction with their hosts, and it provides further evidence for the role of amoebae as training grounds for bacterial pathogens of humans.
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Iovieno A, Ledee DR, Miller D, Alfonso EC. Detection of bacterial endosymbionts in clinical acanthamoeba isolates. Ophthalmology 2010; 117:445-52, 452.e1-3. [PMID: 20031220 DOI: 10.1016/j.ophtha.2009.08.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 08/23/2009] [Accepted: 08/25/2009] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To determine the presence of 4 clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK. DESIGN Experimental study. PARTICIPANTS Acanthamoeba isolates (N = 37) recovered from the cornea and contact lens paraphernalia of 23 patients with culture-proven AK and 1 environmental isolate. METHODS Acanthamoeba isolates were evaluated for the presence of microbial endosymbionts belonging to the bacterial genera Legionella, Pseudomonas, Mycobacterium, and Chlamydia using molecular techniques (polymerase chain reaction and sequence analysis, fluorescence in situ hybridization) and transmission electron microscopy. Corneal toxicity and virulence of Acanthamoeba isolates with and without endosymbionts were compared using a cytopathic effect (CPE) assay on human corneal epithelial cells in vitro. Initial visual acuity, location and characteristics of the infiltrate, time to detection of the infection, and symptom duration at presentation were evaluated in all patients. MAIN OUTCOME MEASURES Prevalence and potential pathobiology of bacterial endosymbionts detected in Acanthamoeba isolates recovered from AK. RESULTS Twenty-two (59.4%) of the 38 cultures examined contained at least 1 bacterial endosymbiont. One isolate contained 2 endosymbionts, Legionella and Chlamydia, confirmed by fluorescence in situ hybridization. Corneal toxicity (CPE) was significantly higher for Acanthamoeba-hosting endosymbionts compared with isolates without endosymbionts (P<0.05). Corneal pathogenic endosymbionts such as Pseudomonas and Mycobacterium enhanced Acanthamoeba CPE significantly more than Legionella (P<0.05). In the presence of bacterial endosymbionts, there was a trend toward worse initial visual acuity (P>0.05), central location (P<0.05), absence of radial perineuritis (P<0.05), delayed time to detection (P>0.05), and longer symptom duration at presentation (P>0.05). CONCLUSIONS Most Acanthamoeba isolates responsible for AK harbor 1 or more bacterial endosymbionts. The presence of endosymbionts enhances the corneal pathogenicity of Acanthamoeba isolates and may impact detection time and clinical features of AK.
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Affiliation(s)
- Alfonso Iovieno
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami-Miller School of Medicine, Miami, Florida 33136, USA
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Martínez-Girón R, Doganci L, Iraola V. Gregarines in Dermatophagoides spp. (Acari: Pyroglyphidae): light microscopy observation. JOURNAL OF MEDICAL ENTOMOLOGY 2009; 46:367-368. [PMID: 19351089 DOI: 10.1603/033.046.0223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Recently there has been an increasing interest in studying arthropods that live close to humans, such as cockroaches and mites, for their potential as vectors. Gregarines observed under light microscopy in intestinal extracts of house dust mites (Dermatophagoides spp.) are described for the first time in scientific literature.
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Affiliation(s)
- Rafael Martínez-Girón
- Unidad de Investigación en Patología Respiratoria Protozoaria, Fundación INCLINICA, Oviedo, Spain.
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Schmitz-Esser S, Toenshoff ER, Haider S, Heinz E, Hoenninger VM, Wagner M, Horn M. Diversity of bacterial endosymbionts of environmental acanthamoeba isolates. Appl Environ Microbiol 2008; 74:5822-31. [PMID: 18641160 PMCID: PMC2547052 DOI: 10.1128/aem.01093-08] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 07/11/2008] [Indexed: 11/20/2022] Open
Abstract
Free-living amoebae are frequent hosts for bacterial endosymbionts. In this study, the symbionts of eight novel environmental Acanthamoeba strains isolated from different locations worldwide were characterized. Phylogenetic analysis revealed that they were related to one of four evolutionary lineages of amoeba symbionts recognized previously. This study provides evidence for the existence of only a small number of phylogenetically well-separated groups of obligate intracellular endosymbionts of acanthamoebae with global distribution.
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MESH Headings
- Acanthamoeba/genetics
- Acanthamoeba/microbiology
- Animals
- Bacteria/classification
- Bacteria/genetics
- Biodiversity
- DNA, Bacterial/genetics
- DNA, Protozoan/genetics
- Genes, Bacterial
- Genes, Protozoan
- Genes, rRNA
- Geologic Sediments/microbiology
- Molecular Sequence Data
- Phylogeny
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 18S/genetics
- Sequence Analysis, DNA
- Soil Microbiology
- Symbiosis
- Water Microbiology
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Affiliation(s)
- Stephan Schmitz-Esser
- Department of Microbial Ecology, University of Vienna, Althanstr. 14, 1090 Vienna, Austria
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Becker B, Hoef-Emden K, Melkonian M. Chlamydial genes shed light on the evolution of photoautotrophic eukaryotes. BMC Evol Biol 2008; 8:203. [PMID: 18627593 PMCID: PMC2490706 DOI: 10.1186/1471-2148-8-203] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 07/15/2008] [Indexed: 11/10/2022] Open
Abstract
Background Chlamydiae are obligate intracellular bacteria of protists, invertebrates and vertebrates, but have not been found to date in photosynthetic eukaryotes (algae and embryophytes). Genes of putative chlamydial origin, however, are present in significant numbers in sequenced genomes of photosynthetic eukaryotes. It has been suggested that such genes were acquired by an ancient horizontal gene transfer from Chlamydiae to the ancestor of photosynthetic eukaryotes. To further test this hypothesis, an extensive search for proteins of chlamydial origin was performed using several recently sequenced algal genomes and EST databases, and the proteins subjected to phylogenetic analyses. Results A total of 39 proteins of chlamydial origin were retrieved from the photosynthetic eukaryotes analyzed and their identity verified through phylogenetic analyses. The distribution of the chlamydial proteins among four groups of photosynthetic eukaryotes (Viridiplantae, Rhodoplantae, Glaucoplantae, Bacillariophyta) was complex suggesting multiple acquisitions and losses. Evidence is presented that all except one of the chlamydial genes originated from an ancient endosymbiosis of a chlamydial bacterium into the ancestor of the Plantae before their divergence into Viridiplantae, Rhodoplantae and Glaucoplantae, i.e. more than 1.1 BYA. The chlamydial proteins subsequently spread through secondary plastid endosymbioses to other eukaryotes. Of 20 chlamydial proteins recovered from the genomes of two Bacillariophyta, 10 were of rhodoplant, and 10 of viridiplant origin suggesting that they were acquired by two different secondary endosymbioses. Phylogenetic analyses of concatenated sequences demonstrated that the viridiplant secondary endosymbiosis likely occurred before the divergence of Chlorophyta and Streptophyta. Conclusion We identified 39 proteins of chlamydial origin in photosynthetic eukaryotes signaling an ancient invasion of the ancestor of the Plantae by a chlamydial bacterium accompanied by horizontal gene transfer. Subsequently, chlamydial proteins spread through secondary endosymbioses to other eukaryotes. We conclude that intracellular chlamydiae likely persisted throughout the early history of the Plantae donating genes to their hosts that replaced their cyanobacterial/plastid homologs thus shaping early algal/plant evolution before they eventually vanished.
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Affiliation(s)
- Burkhard Becker
- Botanisches Institut, Universität zu Köln, Gyrhofstr. 15, 50931 Köln, Germany.
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Thomas V, Loret JF, Jousset M, Greub G. Biodiversity of amoebae and amoebae-resisting bacteria in a drinking water treatment plant. Environ Microbiol 2008; 10:2728-45. [DOI: 10.1111/j.1462-2920.2008.01693.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pagnier I, Raoult D, La Scola B. Isolation and identification of amoeba-resisting bacteria from water in human environment by using an Acanthamoeba polyphaga co-culture procedure. Environ Microbiol 2008; 10:1135-44. [PMID: 18279351 DOI: 10.1111/j.1462-2920.2007.01530.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Amoeba-resisting bacteria (ARB) such as Legionella spp. are currently regarded as potential human pathogens living in the environment. To detect ARB from both human and environmental samples, co-culture with amoebae has been demonstrated as an efficient tool. However, using this procedure, mostly water from cooling towers and hospital water supplies have been investigated as the possible reservoir of ARB. In the present study, we studied ARB population in 77 environmental water samples including rivers, fountains, lakes and domestic wells in the south of France. As a result, a total of 244 isolates corresponding to 89 different species of ARB, but not Legionella spp., were identified. Ability to grow within and/or to be lytic for amoebae was revealed for the first time for several human pathogens. Six isolates are likely to be the members of a new or uncharacterized genus/species. An anaerobic bacterium, Clostridium frigidicarnis was demonstrated to be lytic for amoebae. This preliminary work demonstrates that the water environment in the vicinity of humans is a reservoir of ARB, including well-known pathogens for which amoebae and/or water was not recognized earlier as a possible reservoir.
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Affiliation(s)
- Isabelle Pagnier
- Unité des Rickettsies, CNRS UMR 6020, Faculté de Médecine de Marseille, 13385 Marseille Cedex 05, France
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