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Mohammed V, Arockiaraj J. Unveiling the trifecta of cyanobacterial quorum sensing: LuxI, LuxR and LuxS as the intricate machinery for harmful algal bloom formation in freshwater ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171644. [PMID: 38471587 DOI: 10.1016/j.scitotenv.2024.171644] [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: 06/28/2023] [Revised: 02/22/2024] [Accepted: 03/09/2024] [Indexed: 03/14/2024]
Abstract
Harmful algal blooms (HABs) are causing significant disruptions in freshwater ecosystems, primarily due to the proliferation of cyanobacteria. These blooms have a widespread impact on various lakes globally, leading to profound environmental and health consequences. Cyanobacteria, with their ability to produce diverse toxins, pose a particular concern as they negatively affect the well-being of humans and animals, exacerbating the situation. Notably, cyanobacteria utilize quorum sensing (QS) as a complex communication mechanism that facilitates coordinated growth and toxin production. QS plays a critical role in regulating the dynamics of HABs. However, recent advances in control and mitigation strategies have shown promising results in effectively managing and reducing the occurrence of HABs. This comprehensive review explores the intricate aspects of cyanobacteria development in freshwater ecosystems, explicitly focusing on deciphering the signaling molecules associated with QS and their corresponding genes. Furthermore, a concise overview of diverse measures implemented to efficiently control and mitigate the spread of these bacteria will be provided, shedding light on the ongoing global efforts to address this urgent environmental issue. By deepening our understanding of the mechanisms driving cyanobacteria growth and developing targeted control strategies, we hope to safeguard freshwater ecosystems and protect the health of humans and animals from the detrimental impacts of HABs.
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Affiliation(s)
- Vajagathali Mohammed
- Department of Forensic Science, Yenepoya Institute of Arts, Science, Commerce, and Management, Yenepoya (Deemed to be University), Mangaluru 575013, Karnataka, India
| | - Jesu Arockiaraj
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalpattu District, Tamil Nadu, India.
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2
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Haapanen S, Barker H, Carta F, Supuran CT, Parkkila S. Novel Drug Screening Assay for Acanthamoeba castellanii and the Anti-Amoebic Effect of Carbonic Anhydrase Inhibitors. J Med Chem 2024; 67:152-164. [PMID: 38150360 PMCID: PMC10788897 DOI: 10.1021/acs.jmedchem.3c01020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023]
Abstract
Acanthamoeba castellanii is an amoeba that inhabits soil and water in every part of the world. Acanthamoeba infection of the eye causes keratitis and can lead to a loss of vision. Current treatment options are only moderately effective, have multiple harmful side effects, and are tedious. In our study, we developed a novel drug screening method to define the inhibitory properties of potential new drugs against A. castellanii in vitro. We found that the clinically used carbonic anhydrase inhibitors, acetazolamide, ethoxzolamide, and dorzolamide, have promising antiamoebic properties.
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Affiliation(s)
- Susanna Haapanen
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
| | - Harlan Barker
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
- Fimlab
Ltd, Tampere University Hospital, FI-33520 Tampere, Finland
| | - Fabrizio Carta
- Neurofarba
Department, Sezione di Chimica Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via U. Schiff 6, Sesto Fiorentino, I-50019 Firenze, Italy
| | - Claudiu T. Supuran
- Neurofarba
Department, Sezione di Chimica Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via U. Schiff 6, Sesto Fiorentino, I-50019 Firenze, Italy
| | - Seppo Parkkila
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
- Fimlab
Ltd, Tampere University Hospital, FI-33520 Tampere, Finland
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3
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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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4
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The inside scoop: Comparative genomics of two intranuclear bacteria, "Candidatus Berkiella cookevillensis" and "Candidatus Berkiella aquae". PLoS One 2022; 17:e0278206. [PMID: 36584052 PMCID: PMC9803151 DOI: 10.1371/journal.pone.0278206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/12/2022] [Indexed: 12/31/2022] Open
Abstract
"Candidatus Berkiella cookevillensis" (strain CC99) and "Candidatus Berkiella aquae" (strain HT99), belonging to the Coxiellaceae family, are gram-negative bacteria isolated from amoebae in biofilms present in human-constructed water systems. Both bacteria are obligately intracellular, requiring host cells for growth and replication. The intracellular bacteria-containing vacuoles of both bacteria closely associate with or enter the nuclei of their host cells. In this study, we analyzed the genome sequences of CC99 and HT99 to better understand their biology and intracellular lifestyles. The CC99 genome has a size of 2.9Mb (37.9% GC) and contains 2,651 protein-encoding genes (PEGs) while the HT99 genome has a size of 3.6Mb (39.4% GC) and contains 3,238 PEGs. Both bacteria encode high proportions of hypothetical proteins (CC99: 46.5%; HT99: 51.3%). The central metabolic pathways of both bacteria appear largely intact. Genes for enzymes involved in the glycolytic pathway, the non-oxidative branch of the phosphate pathway, the tricarboxylic acid pathway, and the respiratory chain were present. Both bacteria, however, are missing genes for the synthesis of several amino acids, suggesting reliance on their host for amino acids and intermediates. Genes for type I and type IV (dot/icm) secretion systems as well as type IV pili were identified in both bacteria. Moreover, both bacteria contain genes encoding large numbers of putative effector proteins, including several with eukaryotic-like domains such as, ankyrin repeats, tetratricopeptide repeats, and leucine-rich repeats, characteristic of other intracellular bacteria.
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5
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Nagakubo T. Biological Functions and Applications of Virus-Related Bacterial Nanoparticles: A Review. Int J Mol Sci 2022; 23:ijms23052595. [PMID: 35269736 PMCID: PMC8910223 DOI: 10.3390/ijms23052595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 12/25/2022] Open
Abstract
Accumulating evidence suggests that microorganisms produce various nanoparticles that exhibit a variety of biological functions. The structure of these bacterial nanoparticles ranges from membrane vesicles composed of membrane lipids to multicomponent proteinaceous machines. Of bacterial nanoparticles, bacterial phage tail-like nanoparticles, associated with virus-related genes, are found in bacteria from various environments and have diverse functions. Extracellular contractile injection systems (eCISs), a type of bacterial phage tail-like nanostructure, have diverse biological functions that mediate the interactions between the producer bacteria and target eukaryote. Known gram-negative bacterial eCISs can act as protein translocation systems and inject effector proteins that modulate eukaryotic cellular processes by attaching to the target cells. Further investigation of the functions of eCISs will facilitate the application of these nanomachines as nano-sized syringes in the field of nanomedicine and vaccine development. This review summarises the recent progress in elucidating the structures and biological functions of nanoparticles that resemble the tail components of phages that infect bacteria and discusses directions for future research to improve the clinical applicability of virus-related bacterial nanoparticles.
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Affiliation(s)
- Toshiki Nagakubo
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8577, Japan;
- Microbiology Research Centre for Sustainability (MiCS), University of Tsukuba, Tsukuba 305-8577, Japan
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6
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Selberherr E, Penz T, König L, Conrady B, Siegl A, Horn M, Schmitz-Esser S. The life cycle-dependent transcriptional profile of the obligate intracellular amoeba symbiont Amoebophilus asiaticus. FEMS Microbiol Ecol 2022; 98:6499296. [PMID: 34999767 PMCID: PMC8831229 DOI: 10.1093/femsec/fiac001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/22/2021] [Accepted: 01/04/2022] [Indexed: 12/04/2022] Open
Abstract
Free-living amoebae often harbor obligate intracellular bacterial symbionts. Amoebophilus (A.) asiaticus is a representative of a lineage of amoeba symbionts in the phylum Bacteroidota. Here, we analyse the transcriptome of A. asiaticus strain 5a2 at four time points during its infection cycle and replication within the Acanthamoeba host using RNA sequencing. Our results reveal a dynamic transcriptional landscape throughout different A. asiaticus life cycle stages. Many intracellular bacteria and pathogens utilize eukaryotic-like proteins (ELPs) for host cell interaction and the A. asiaticus 5a2 genome shows a particularly high abundance of ELPs. We show the expression of all genes encoding ELPs and found many ELPs to be differentially expressed. At the replicative stage of A. asiaticus, ankyrin repeat proteins and tetratricopeptide/Sel1-like repeat proteins were upregulated. At the later time points, high expression levels of a type 6 secretion system that likely prepares for a new infection cycle after lysing its host, were found. This study reveals comprehensive insights into the intracellular lifestyle of A. asiaticus and highlights candidate genes for host cell interaction. The results from this study have implications for other intracellular bacteria such as other amoeba-associated bacteria and the arthropod symbionts Cardinium forming the sister lineage of A. asiaticus.
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Affiliation(s)
- E Selberherr
- Unit of Food Microbiology, Institute of Food Safety, Food Technology and Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Austria
| | - T Penz
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.,current affiliation: CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - L König
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - B Conrady
- Department of Veterinary and Animal Science, University of Copenhagen, Denmark
| | - A Siegl
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - M Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - S Schmitz-Esser
- Department of Animal Science, Iowa State University, Ames, USA
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7
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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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8
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War of the microbial world: Acanthamoeba spp. interactions with microorganisms. Folia Microbiol (Praha) 2021; 66:689-699. [PMID: 34145552 PMCID: PMC8212903 DOI: 10.1007/s12223-021-00889-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 06/09/2021] [Indexed: 12/15/2022]
Abstract
Acanthamoeba is known to interact with a plethora of microorganisms such as bacteria, fungi and viruses. In these interactions, the amoebae can be predatory in nature, transmission vehicle or an incubator. Amoebae consume microorganisms, especially bacteria, as food source to fulfil their nutritional needs by taking up bacteria through phagocytosis and lysing them in phagolysosomes and hence play an eminent role in the regulation of bacterial density in the nature and accountable for eradication of around 60% of the bacterial population in the environment. Acanthamoeba can also act as a “Trojan horse” for microbial transmission in the environment. Additionally, Acanthamoeba may serve as an incubator-like reservoir for microorganisms, including those that are pathogenic to humans, where the microorganisms use amoebae’s defences to resist harsh environment and evade host defences and drugs, whilst growing in numbers inside the amoebae. Furthermore, amoebae can also be used as a “genetic melting pot” where exchange of genes as well as adaptation of microorganisms, leading to higher pathogenicity, may arise. Here, we describe bacteria, fungi and viruses that are known to interact with Acanthamoeba spp.
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9
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Almeida C. A potential third-order role of the host endoplasmic reticulum as a contact site in interkingdom microbial endosymbiosis and viral infection. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:255-271. [PMID: 33559322 DOI: 10.1111/1758-2229.12938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
The normal functioning of eukaryotic cells depends on the compartmentalization of metabolic processes within specific organelles. Interactions among organelles, such as those between the endoplasmic reticulum (ER) - considered the largest single structure in eukaryotic cells - and other organelles at membrane contact sites (MCSs) have also been suggested to trigger synergisms, including intracellular immune responses against pathogens. In addition to the ER-endogenous functions and ER-organelle MCSs, we present the perspective of a third-order role of the ER as a host contact site for endosymbiotic microbial non-pathogens and pathogens, from endosymbiont bacteria to parasitic protists and viruses. Although understudied, ER-endosymbiont interactions have been observed in a range of eukaryotic hosts, including protists, plants, algae, and metazoans. Host ER interactions with endosymbionts could be an ER function built from ancient, conserved mechanisms selected for communicating with mutualistic endosymbionts in specific life cycle stages, and they may be exploited by pathogens and parasites. The host ER-'guest' interactome and traits in endosymbiotic biology are briefly discussed. The acknowledgment and understanding of these possible mechanisms might reveal novel evolutionary perspectives, uncover the causes of unexplained cellular disorders and suggest new pharmacological targets.
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Affiliation(s)
- Celso Almeida
- ENDOBIOS Biotech®, Praceta Progresso Clube n° 6, 2725-110 Mem-Martins, Portugal
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10
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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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11
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Oren A, Garrity GM, Parker CT, Chuvochina M, Trujillo ME. Lists of names of prokaryotic Candidatus taxa. Int J Syst Evol Microbiol 2020; 70:3956-4042. [DOI: 10.1099/ijsem.0.003789] [Citation(s) in RCA: 782] [Impact Index Per Article: 195.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We here present annotated lists of names of Candidatus taxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status of Candidatus taxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names of Candidatus taxa with additions and corrections to the current lists to be published periodically in the International Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of the Candidatus names if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.
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Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 9190401 Jerusalem, Israel
| | - George M. Garrity
- NamesforLife, LLC, PO Box 769, Okemos MI 48805-0769, USA
- Department of Microbiology & Molecular Genetics, Biomedical Physical Sciences, Michigan State University, East Lansing, MI 48824-4320, USA
| | | | - Maria Chuvochina
- Australian Centre for Ecogenomics, University of Queensland, St. Lucia QLD 4072, Brisbane, Australia
| | - Martha E. Trujillo
- Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, 37007, Salamanca, Spain
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12
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Huggett MJ, Apprill A. Coral microbiome database: Integration of sequences reveals high diversity and relatedness of coral-associated microbes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:372-385. [PMID: 30094953 PMCID: PMC7379671 DOI: 10.1111/1758-2229.12686] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 08/04/2018] [Indexed: 05/10/2023]
Abstract
Coral-associated microorganisms are thought to play a fundamental role in the health and ecology of corals, but understanding of specific coral-microbial interactions are lacking. In order to create a framework to examine coral-microbial specificity, we integrated and phylogenetically compared 21,100 SSU rRNA gene Sanger-produced sequences from bacteria and archaea associated with corals from previous studies, and accompanying host, location and publication metadata, to produce the Coral Microbiome Database. From this database, we identified 39 described and candidate phyla of Bacteria and two Archaea phyla associated with corals, demonstrating that corals are one of the most phylogenetically diverse animal microbiomes. Secondly, this new phylogenetic resource shows that certain microorganisms are indeed specific to corals, including evolutionary distinct hosts. Specifically, we identified 2-37 putative monophyletic, coral-specific sequence clusters within bacterial genera associated with the greatest number of coral species (Vibrio, Endozoicomonas and Ruegeria) as well as functionally relevant microbial taxa ("Candidatus Amoebophilus", "Candidatus Nitrosopumilus" and under recognized cyanobacteria). This phylogenetic resource provides a framework for more targeted studies of corals and their specific microbial associates, which is timely given the escalated need to understand the role of the coral microbiome and its adaptability to changing ocean and reef conditions.
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Affiliation(s)
- Megan J. Huggett
- School of Environmental and Life SciencesUniversity of NewcastleOurimbahNSW, 2258Australia
- School of ScienceEdith Cowan UniversityJoondalupWAAustralia
| | - Amy Apprill
- Marine Chemistry and Geochemistry DepartmentWoods Hole Oceanographic InstitutionWoods HoleMAUSA
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13
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Samba-Louaka A, Delafont V, Rodier MH, Cateau E, Héchard Y. Free-living amoebae and squatters in the wild: ecological and molecular features. FEMS Microbiol Rev 2019; 43:415-434. [DOI: 10.1093/femsre/fuz011] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/30/2019] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT
Free-living amoebae are protists frequently found in water and soils. They feed on other microorganisms, mainly bacteria, and digest them through phagocytosis. It is accepted that these amoebae play an important role in the microbial ecology of these environments. There is a renewed interest for the free-living amoebae since the discovery of pathogenic bacteria that can resist phagocytosis and of giant viruses, underlying that amoebae might play a role in the evolution of other microorganisms, including several human pathogens. Recent advances, using molecular methods, allow to bring together new information about free-living amoebae. This review aims to provide a comprehensive overview of the newly gathered insights into (1) the free-living amoeba diversity, assessed with molecular tools, (2) the gene functions described to decipher the biology of the amoebae and (3) their interactions with other microorganisms in the environment.
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Affiliation(s)
- Ascel Samba-Louaka
- Laboratoire Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, 1 rue Georges Bonnet, TSA51106, 86073 POITIERS Cedex 9, France
| | - Vincent Delafont
- Laboratoire Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, 1 rue Georges Bonnet, TSA51106, 86073 POITIERS Cedex 9, France
| | - Marie-Hélène Rodier
- Laboratoire Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, 1 rue Georges Bonnet, TSA51106, 86073 POITIERS Cedex 9, France
- Laboratoire de Parasitologie et Mycologie, CHU La Milétrie, 2 rue de la Milétrie, 86021 Poitiers Cedex, France
| | - Estelle Cateau
- Laboratoire Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, 1 rue Georges Bonnet, TSA51106, 86073 POITIERS Cedex 9, France
- Laboratoire de Parasitologie et Mycologie, CHU La Milétrie, 2 rue de la Milétrie, 86021 Poitiers Cedex, France
| | - Yann Héchard
- Laboratoire Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, 1 rue Georges Bonnet, TSA51106, 86073 POITIERS Cedex 9, France
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The Origin and Evolution of Release Factors: Implications for Translation Termination, Ribosome Rescue, and Quality Control Pathways. Int J Mol Sci 2019; 20:ijms20081981. [PMID: 31018531 PMCID: PMC6514570 DOI: 10.3390/ijms20081981] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 01/26/2023] Open
Abstract
The evolution of release factors catalyzing the hydrolysis of the final peptidyl-tRNA bond and the release of the polypeptide from the ribosome has been a longstanding paradox. While the components of the translation apparatus are generally well-conserved across extant life, structurally unrelated release factor peptidyl hydrolases (RF-PHs) emerged in the stems of the bacterial and archaeo-eukaryotic lineages. We analyze the diversification of RF-PH domains within the broader evolutionary framework of the translation apparatus. Thus, we reconstruct the possible state of translation termination in the Last Universal Common Ancestor with possible tRNA-like terminators. Further, evolutionary trajectories of the several auxiliary release factors in ribosome quality control (RQC) and rescue pathways point to multiple independent solutions to this problem and frequent transfers between superkingdoms including the recently characterized ArfT, which is more widely distributed across life than previously appreciated. The eukaryotic RQC system was pieced together from components with disparate provenance, which include the long-sought-after Vms1/ANKZF1 RF-PH of bacterial origin. We also uncover an under-appreciated evolutionary driver of innovation in rescue pathways: effectors deployed in biological conflicts that target the ribosome. At least three rescue pathways (centered on the prfH/RFH, baeRF-1, and C12orf65 RF-PH domains), were likely innovated in response to such conflicts.
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Ponnusamy L, Willcox AC, Roe RM, Davidson SA, Linsuwanon P, Schuster AL, Richards AL, Meshnick SR, Apperson CS. Bacterial microbiome of the chigger mite Leptotrombidium imphalum varies by life stage and infection with the scrub typhus pathogen Orientia tsutsugamushi. PLoS One 2018; 13:e0208327. [PMID: 30521561 PMCID: PMC6283546 DOI: 10.1371/journal.pone.0208327] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 11/15/2018] [Indexed: 02/01/2023] Open
Abstract
Scrub typhus is a mites-borne rickettsiosis caused by the obligate intracellular Gram-negative bacterium Orientia tsutsugamushi. The disease is potentially life threatening and is prevalent in tropical Asia, islands of the western Pacific Ocean and northern Australia where an estimated one million cases occur annually. Orientia tsutsugamushi is transmitted by the bite of larval mites in the genus Leptotrombidium. In the present study, the composition of the microbiome in larvae, deutonymphs and adult males and females from laboratory colonies of L. imphalum that were infected as well as uninfected with O. tsutsugamushi were investigated by high-throughput sequencing of the bacterial 16S rRNA gene. Notably, the bacterial microbiomes of infected adult females were dominated by sequences of O. tsutsugamushi and an unidentified species of Amoebophilaceae, which together comprised 98.2% of bacterial sequences. To improve the taxonomic resolution of the Amoebophilaceae OTU a nearly full length sequence of the 16S rRNA gene was amplified, cloned, and Sanger sequenced. Infected female mites had 89 to 92% nucleotide identity with the Amoebophilaceae family, indicating that the bacterium was likely to be a species of a novel genus. The species composition of bacterial communities varied between mite life stages regardless of their infection status. Uninfected adults exhibited greater species diversity than adults infected with O. tsutsugamushi. In the infected colony, the rate of filial infection with Orientia was less than 100%. Larval and male mites that were PCR-negative for Orientia contained low numbers of sequences of Amoebophilaceae (0.01 and 0.06%, respectively) in their taxonomic profiles, suggesting that a mutualistic relationship exists between the novel species of Amoebophilaceae and O. tsutsugamushi. Our study findings provide the basis for further research to determine the influence of the novel Amoebophilaceae species on the bacterial microbiome and on vector susceptibility to and transovarial transmission of O. tsutsugamushi.
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Affiliation(s)
- Loganathan Ponnusamy
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
- Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail: (LP); (CSA)
| | - Alexandra C. Willcox
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - R. Michael Roe
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Silas A. Davidson
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Piyada Linsuwanon
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Anthony L. Schuster
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Allen L. Richards
- Naval Medical Research Center, Viral and Rickettsial Diseases Department, Silver Spring, Maryland, United States of America
| | - Steven R. Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Charles S. Apperson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
- Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail: (LP); (CSA)
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16
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Chan LL, Mak JW, Ambu S, Chong PY. Identification and ultrastructural characterization of Acanthamoeba bacterial endocytobionts belonging to the Alphaproteobacteria class. PLoS One 2018; 13:e0204732. [PMID: 30356282 PMCID: PMC6200196 DOI: 10.1371/journal.pone.0204732] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 09/13/2018] [Indexed: 12/17/2022] Open
Abstract
The detection and identification of two endocytobiotic bacterial strains, one affiliated to the “Candidatus Caedibacter acanthamoebae”/“Ca. Paracaedimonas acanthamoeba”, and another to the endosymbiont of Acanthamoeba UWC8 and “Ca. Jidaibacter acanthamoeba” are described. For endocytobiont screening, we developed a PCR method with a set of broad-range bacterial 16S rRNA primers to substitute the commonly used but technically demanding fluorescent in situ hybridization technique. Our PCR test alone without sequencing failed to discriminate the endocytobiont-containing and endocytobiont-free Acanthamoeba sp. due to the presence of mismatched primers to host mitochondrial DNA. We highlighted the need to perform bacterial primer checking against the Acanthamoeba genome to avoid false positive detection in PCR. Although the genetic aspect of “Ca. Caedibacter acanthamoebae”/“Ca. Paracaedimonas acanthamoeba” and the endosymbiont of Acanthamoeba UWC8/“Ca. Jidaibacter acanthamoeba” are well studied, knowledge pertaining to their morphologies are quite vague. Hence, we used transmission electron microscopy to examine our endocytobionts which are affiliated to previously described intracellular bacteria of Acanthamoeba sp. We used good-quality TEM images for the localization and the fate of the current endocytobionts inside different life stages of the hosts. Furthermore, to the best of our knowledge, our TEM findings are the first to provide morphological evidence for the clearance of defective Acanthamoeba endocytobionts via an autophagic-like process.
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Affiliation(s)
- Li Li Chan
- Pathology Division, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
- * E-mail:
| | - Joon Wah Mak
- Pathology Division, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
- School of Postgraduate Studies and Research, International Medical University, Kuala Lumpur, Malaysia
| | - Stephen Ambu
- Pathology Division, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
- School of Postgraduate Studies and Research, International Medical University, Kuala Lumpur, Malaysia
| | - Pei Yee Chong
- Medical Sciences, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
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17
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Wang Z, Wu M. Comparative Genomic Analysis of Acanthamoeba Endosymbionts Highlights the Role of Amoebae as a "Melting Pot" Shaping the Rickettsiales Evolution. Genome Biol Evol 2018; 9:3214-3224. [PMID: 29177480 PMCID: PMC5751055 DOI: 10.1093/gbe/evx246] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2017] [Indexed: 11/12/2022] Open
Abstract
Amoebae have been considered as a genetic "melting pot" for its symbionts, facilitating genetic exchanges of the bacteria that co-inhabit the same host. To test the "melting pot" hypothesis, we analyzed six genomes of amoeba endosymbionts within Rickettsiales, four of which belong to Holosporaceae family and two to Candidatus Midichloriaceae. For the first time, we identified plasmids in obligate amoeba endosymbionts, which suggests conjugation as a potential mechanism for lateral gene transfers (LGTs) that underpin the "melting pot" hypothesis. We found strong evidence of recent LGTs between the Rickettsiales amoeba endosymbionts, suggesting that the LGTs are continuous and ongoing. In addition, comparative genomic and phylogenomic analyses revealed pervasive and recurrent LGTs between Rickettsiales and distantly related amoeba-associated bacteria throughout the Rickettsiales evolution. Many of these exchanged genes are important for amoeba-symbiont interactions, including genes in transport system, antibiotic resistance, stress response, and bacterial virulence, suggesting that LGTs have played important roles in the adaptation of endosymbionts to their intracellular habitats. Surprisingly, we found little evidence of LGTs between amoebae and their bacterial endosymbionts. Our study strongly supports the "melting pot" hypothesis and highlights the role of amoebae in shaping the Rickettsiales evolution.
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Affiliation(s)
- Zhang Wang
- Department of Biology, University of Virginia
| | - Martin Wu
- Department of Biology, University of Virginia
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18
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Böck D, Medeiros JM, Tsao HF, Penz T, Weiss GL, Aistleitner K, Horn M, Pilhofer M. In situ architecture, function, and evolution of a contractile injection system. Science 2017; 357:713-717. [PMID: 28818949 DOI: 10.1126/science.aan7904] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/17/2017] [Indexed: 12/27/2022]
Abstract
Contractile injection systems mediate bacterial cell-cell interactions by a bacteriophage tail-like structure. In contrast to extracellular systems, the type 6 secretion system (T6SS) is defined by intracellular localization and attachment to the cytoplasmic membrane. Here we used cryo-focused ion beam milling, electron cryotomography, and functional assays to study a T6SS in Amoebophilus asiaticus The in situ architecture revealed three modules, including a contractile sheath-tube, a baseplate, and an anchor. All modules showed conformational changes upon firing. Lateral baseplate interactions coordinated T6SSs in hexagonal arrays. The system mediated interactions with host membranes and may participate in phagosome escape. Evolutionary sequence analyses predicted that T6SSs are more widespread than previously thought. Our insights form the basis for understanding T6SS key concepts and exploring T6SS diversity.
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Affiliation(s)
- Désirée Böck
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - João M Medeiros
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Han-Fei Tsao
- Division of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria
| | - Thomas Penz
- Division of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria
| | - Gregor L Weiss
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Karin Aistleitner
- Division of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria
| | - Matthias Horn
- Division of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria.
| | - Martin Pilhofer
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland.
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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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20
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Molecular identification of bacterial endosymbionts of Sappinia strains. Parasitol Res 2016; 116:549-558. [PMID: 27830372 DOI: 10.1007/s00436-016-5319-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/28/2016] [Indexed: 10/20/2022]
Abstract
The genus Sappinia comprises free-living amoebae occurring worldwide in a variety of habitats such as soils, plant matter and freshwater ponds, but also animal faeces, and includes at present three species, S. pedata, S. diploidea and S. platani. The genus is potentially pathogenic, as indicated by the identification of S. pedata in a case of human amoebic encephalitis. Electron microscopy studies on some strains already revealed intracellular bacteria in Sappinia. In the current study, we performed 16S ribosomal RNA gene (rDNA) analysis of these bacterial endosymbionts. We first inferred relationships among Sappinia strains on the basis of 18S rDNA, demonstrating that S. pedata emerged as sister to a larger clade including S. diploidea, S. platani and a few 'S. diploidea-like' strains. Thus, bacterial 16S rDNA was searched for in representative strains of each Sappinia species/subgroup. We found that Sappinia strains were associated to distinct species of Flavobacterium or Pedobacter (phylum Bacteroidetes). These appear to be distributed following the amoebal host subgroups, and are not directly related to other Bacteroidetes species known as interacting with free-living amoebae. While all the endosymbionts' close relatives are known to grow on agar, bacteriological media inoculated with amoebal extracts remained negative. Overall, results indicate that the recovered bacteria are likely specific obligate endosymbionts of Sappinia species. Further studies, including additional amoebal strains and deep morphological and molecular analyses, will be necessary to confirm this hypothesis.
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21
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Distinguishing between Microbial Habitats Unravels Ecological Complexity in Coral Microbiomes. mSystems 2016; 1:mSystems00143-16. [PMID: 27822559 PMCID: PMC5080407 DOI: 10.1128/msystems.00143-16] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 01/07/2023] Open
Abstract
The diverse prokaryotic communities associated with reef-building corals may provide important ecological advantages to their threatened hosts. The consistency of relationships between corals and specific prokaryotes, however, is debated, and the locations where microbially mediated processes occur in the host are not resolved. Here, we examined how the prokaryotic associates of five common Caribbean corals with different evolutionary and ecological traits differ across mucus and tissue habitats. We used physical and chemical separation of coral mucus and tissue and sequencing of partial small-subunit rRNA genes of bacteria and archaea from these samples to demonstrate that coral tissue and mucus harbor unique reservoirs of prokaryotes, with 23 to 49% and 31 to 56% of sequences exclusive to the tissue and mucus habitats, respectively. Across all coral species, we found that 46 tissue- and 22 mucus-specific microbial members consistently associated with the different habitats. Sequences classifying as "Candidatus Amoebophilus," Bacteroidetes-affiliated intracellular symbionts of amoebae, emerged as previously unrecognized tissue associates of three coral species. This study demonstrates how coral habitat differentiation enables highly resolved examination of ecological interactions between corals and their associated microorganisms and identifies previously unrecognized tissue and mucus associates of Caribbean corals for future targeted study. IMPORTANCE This study demonstrates that coral tissue or mucus habitats structure the microbiome of corals and that separation of these habitats facilitates identification of consistent microbial associates. Using this approach, we demonstrated that sequences related to "Candidatus Amoebophilus," recognized intracellular symbionts of amoebae, were highly associated with the tissues of Caribbean corals and possibly endosymbionts of a protistan host within corals, adding a further degree of intricacy to coral holobiont symbioses. Examining specific habitats within complex hosts such as corals is useful for targeting important microbial associations that may otherwise be masked by the sheer microbial diversity associated with all host habitats.
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Delafont V, Bouchon D, Héchard Y, Moulin L. Environmental factors shaping cultured free-living amoebae and their associated bacterial community within drinking water network. WATER RESEARCH 2016; 100:382-392. [PMID: 27219048 DOI: 10.1016/j.watres.2016.05.044] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/10/2016] [Accepted: 05/13/2016] [Indexed: 05/08/2023]
Abstract
Free-living amoebae (FLA) constitute an important part of eukaryotic populations colonising drinking water networks. However, little is known about the factors influencing their ecology in such environments. Because of their status as reservoir of potentially pathogenic bacteria, understanding environmental factors impacting FLA populations and their associated bacterial community is crucial. Through sampling of a large drinking water network, the diversity of cultivable FLA and their bacterial community were investigated by an amplicon sequencing approach, and their correlation with physicochemical parameters was studied. While FLA ubiquitously colonised the water network all year long, significant changes in population composition were observed. These changes were partially explained by several environmental parameters, namely water origin, temperature, pH and chlorine concentration. The characterisation of FLA associated bacterial community reflected a diverse but rather stable consortium composed of nearly 1400 OTUs. The definition of a core community highlighted the predominance of only few genera, majorly dominated by Pseudomonas and Stenotrophomonas. Co-occurrence analysis also showed significant patterns of FLA-bacteria association, and allowed uncovering potentially new FLA - bacteria interactions. From our knowledge, this study is the first that combines a large sampling scheme with high-throughput identification of FLA together with associated bacteria, along with their influencing environmental parameters. Our results demonstrate the importance of physicochemical parameters in the ecology of FLA and their bacterial community in water networks.
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Affiliation(s)
- Vincent Delafont
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France; Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, 94200 Ivry sur Seine, France
| | - Didier Bouchon
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France
| | - Yann Héchard
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France
| | - Laurent Moulin
- Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, 94200 Ivry sur Seine, France.
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Delafont V, Samba-Louaka A, Bouchon D, Moulin L, Héchard Y. Shedding light on microbial dark matter: a TM6 bacterium as natural endosymbiont of a free-living amoeba. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:970-978. [PMID: 26471960 DOI: 10.1111/1758-2229.12343] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
The TM6 phylum belongs to the so-called microbial dark matter that gathers uncultivated bacteria detected only via DNA sequencing. Recently, the genome sequence of a TM6 bacterium (TM6SC1) has led to suggest that this bacterium would adopt an endosymbiotic life. In the present paper, free-living amoebae bearing a TM6 strain were isolated from a water network. The amoebae were identified as Vermamoeba vermiformis and the presence of a TM6 strain was detected by polymerase chain reaction and microscopy. The partial sequence of its 16S rRNA gene showed this strain to be closely related to the sequenced TM6SC1 strain. These bacteria displayed a pyriform shape and were found within V. vermiformis. Therefore, these bacteria were named Vermiphilus pyriformis. Interactions studies showed that V. pyriformis was highly infectious and that its relation with V. vermiformis was specific and highly stable. Finally, it was found that V. pyriformis inhibited the encystment of V. vermiformis. Overall, this study describes for the first time an endosymbiotic relationship between a TM6 bacterium and a free-living amoeba in the environment. It suggests that other bacteria of the TM6 phylum might also be endosymbiotic bacteria and may be found in other free-living amoebae or other organisms.
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Affiliation(s)
- Vincent Delafont
- Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes, Université de Poitiers, Poitiers, France
- Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, Eau de Paris, 33, avenue Jean Jaurès, 94200, Ivry sur Seine, Paris, France
| | - Ascel Samba-Louaka
- Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes, Université de Poitiers, Poitiers, France
| | - Didier Bouchon
- Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes, Université de Poitiers, Poitiers, France
| | - Laurent Moulin
- Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, Eau de Paris, 33, avenue Jean Jaurès, 94200, Ivry sur Seine, Paris, France
| | - Yann Héchard
- Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes, Université de Poitiers, Poitiers, France
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Silvestre A, Plaze A, Berthon P, Thibeaux R, Guillen N, Labruyère E. In Entamoeba histolytica, a BspA family protein is required for chemotaxis toward tumour necrosis factor. MICROBIAL CELL (GRAZ, AUSTRIA) 2015; 2:235-246. [PMID: 28357299 PMCID: PMC5349171 DOI: 10.15698/mic2015.07.214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/04/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Entamoeba histolytica cell migration is essential for the development of human amoebiasis (an infectious disease characterized by tissue invasion and destruction). The tissue inflammation associated with tumour necrosis factor (TNF) secretion by host cells is a well-documented feature of amoebiasis. Tumour necrosis factor is a chemoattractant for E. histolytica, and the parasite may have a TNF receptor at its cell surface. METHODS confocal microscopy, RNA Sequencing, bioinformatics, RNA antisense techniques and histological analysis of human colon explants were used to characterize the interplay between TNF and E. histolytica. RESULTS an antibody against human TNF receptor 1 (TNFR1) stained the E. histolytica trophozoite surface and (on immunoblots) binds to a 150-kDa protein. Proteome screening with the TNFR1 sequence revealed a BspA family protein in E. histolytica that carries a TNFR signature domain and six leucine-rich repeats (named here as "cell surface protein", CSP, in view of its cellular location). Cell surface protein shares structural homologies with Toll-Like receptors, colocalizes with TNF and is internalized in TNF-containing vesicles. Reduction of cellular CSP levels abolished chemotaxis toward TNF and blocked parasite invasion of human colon. CONCLUSIONS there is a clear link between TNF chemotaxis, CSP and pathogenesis.
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Affiliation(s)
- Anne Silvestre
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, F-75015 Paris, France
- INSERM U786, F-75015 Paris, France
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France
- Université de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France
| | - Aurélie Plaze
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, F-75015 Paris, France
- INSERM U786, F-75015 Paris, France
| | - Patricia Berthon
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France
- Université de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France
| | - Roman Thibeaux
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, F-75015 Paris, France
- INSERM U786, F-75015 Paris, France
| | - Nancy Guillen
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, F-75015 Paris, France
- INSERM U786, F-75015 Paris, France
| | - Elisabeth Labruyère
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, F-75015 Paris, France
- INSERM U786, F-75015 Paris, France
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Current and past strategies for bacterial culture in clinical microbiology. Clin Microbiol Rev 2015; 28:208-36. [PMID: 25567228 DOI: 10.1128/cmr.00110-14] [Citation(s) in RCA: 287] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.
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Loch TP, Faisal M. Emerging flavobacterial infections in fish: A review. J Adv Res 2014; 6:283-300. [PMID: 26257926 PMCID: PMC4522593 DOI: 10.1016/j.jare.2014.10.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 12/05/2022] Open
Abstract
Flavobacterial diseases in fish are caused by multiple bacterial species within the family Flavobacteriaceae and are responsible for devastating losses in wild and farmed fish stocks around the world. In addition to directly imposing negative economic and ecological effects, flavobacterial disease outbreaks are also notoriously difficult to prevent and control despite nearly 100 years of scientific research. The emergence of recent reports linking previously uncharacterized flavobacteria to systemic infections and mortality events in fish stocks of Europe, South America, Asia, Africa, and North America is also of major concern and has highlighted some of the difficulties surrounding the diagnosis and chemotherapeutic treatment of flavobacterial fish diseases. Herein, we provide a review of the literature that focuses on Flavobacterium and Chryseobacterium spp. and emphasizes those associated with fish.
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Affiliation(s)
- Thomas P Loch
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, 174 Food Safety and Toxicology Building, Michigan State University, East Lansing, MI 48824, USA
| | - Mohamed Faisal
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, 174 Food Safety and Toxicology Building, Michigan State University, East Lansing, MI 48824, USA ; Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Natural Resources Building, Room 4, Michigan State University, East Lansing, MI 48824, USA
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Kebbi-Beghdadi C, Greub G. Importance of amoebae as a tool to isolate amoeba-resisting microorganisms and for their ecology and evolution: the Chlamydia paradigm. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:309-24. [PMID: 24992529 DOI: 10.1111/1758-2229.12155] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 02/14/2014] [Accepted: 02/16/2014] [Indexed: 05/23/2023]
Abstract
Free-living amoebae are distributed worldwide and are frequently in contact with humans and animals. As cysts, they can survive in very harsh conditions and resist biocides and most disinfection procedures. Several microorganisms, called amoeba-resisting microorganisms (ARMs), have evolved to survive and multiply within these protozoa. Among them are many important pathogens, such as Legionella and Mycobacteria, and also several newly discovered Chlamydia-related bacteria, such as Parachlamydia acanthamoebae, Estrella lausannensis, Simkania negevensis or Waddlia chondrophila whose pathogenic role towards human or animal is strongly suspected. Amoebae represent an evolutionary crib for their resistant microorganisms since they can exchange genetic material with other ARMs and develop virulence traits that will be further used to infect other professional phagocytes. Moreover, amoebae constitute an ideal tool to isolate strict intracellular microorganisms from complex microbiota, since they will feed on other fast-growing bacteria, such as coliforms potentially present in the investigated samples. The paradigm that ARMs are likely resistant to macrophages, another phagocytic cell, and that they are likely virulent towards humans and animals is only partially true. Indeed, we provide examples of the Chlamydiales order that challenge this assumption and suggest that the ability to multiply in protozoa does not strictly correlate with pathogenicity and that we should rather use the ability to replicate in multiple and diverse eukaryotic cells as an indirect marker of virulence towards mammals. Thus, cell-culture-based microbial culturomics should be used in the future to try to discover new pathogenic bacterial species.
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Affiliation(s)
- Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center, University of Lausanne, Lausanne, Switzerland
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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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29
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Denoncourt AM, Paquet VE, Charette SJ. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria. Front Microbiol 2014; 5:240. [PMID: 24904553 PMCID: PMC4033053 DOI: 10.3389/fmicb.2014.00240] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.
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Affiliation(s)
- Alix M Denoncourt
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval Quebec City, QC, Canada
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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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Santos-Garcia D, Rollat-Farnier PA, Beitia F, Zchori-Fein E, Vavre F, Mouton L, Moya A, Latorre A, Silva FJ. The genome of Cardinium cBtQ1 provides insights into genome reduction, symbiont motility, and its settlement in Bemisia tabaci. Genome Biol Evol 2014; 6:1013-30. [PMID: 24723729 PMCID: PMC4007549 DOI: 10.1093/gbe/evu077] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatus Amoebophilus asiaticus and Cardinium cEper1, endosymbionts of amoeba and wasps, respectively. Reconstruction of their last common ancestors' gene contents revealed an initial massive gene loss from the free-living ancestor. This was followed in Cardinium by smaller losses, associated with settlement in arthropods. Some of these losses, affecting cofactor and amino acid biosynthetic encoding genes, took place in Cardinium cBtQ1 after its divergence from the Cardinium cEper1 lineage and were related to its settlement in the whitefly and its endosymbionts. Furthermore, the Cardinium cBtQ1 genome displays a large proportion of transposable elements, which have recently inactivated genes and produced chromosomal rearrangements. The genome also contains a chromosomal duplication and a multicopy plasmid, which harbors several genes putatively associated with gliding motility, as well as two other genes encoding proteins with potential insecticidal activity. As gene amplification is very rare in endosymbionts, an important function of these genes cannot be ruled out.
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Affiliation(s)
- Diego Santos-Garcia
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Pierre-Antoine Rollat-Farnier
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
- BAMBOO Research team, INRIA Grenoble, Rhône-Alpes, France
| | - Francisco Beitia
- Instituto Valenciano de Investigaciones Agrarias, Unidad Asociada de Entomología IVIA/CIB-CSIC, Valencia, Spain
| | - Einat Zchori-Fein
- Department of Entomology, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Fabrice Vavre
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
- BAMBOO Research team, INRIA Grenoble, Rhône-Alpes, France
| | - Laurence Mouton
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
| | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
- *Corresponding author: E-mail: ;
| | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
- *Corresponding author: E-mail: ;
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Comparative genomics suggests an independent origin of cytoplasmic incompatibility in Cardinium hertigii. PLoS Genet 2012; 8:e1003012. [PMID: 23133394 PMCID: PMC3486910 DOI: 10.1371/journal.pgen.1003012] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/22/2012] [Indexed: 11/28/2022] Open
Abstract
Terrestrial arthropods are commonly infected with maternally inherited bacterial symbionts that cause cytoplasmic incompatibility (CI). In CI, the outcome of crosses between symbiont-infected males and uninfected females is reproductive failure, increasing the relative fitness of infected females and leading to spread of the symbiont in the host population. CI symbionts have profound impacts on host genetic structure and ecology and may lead to speciation and the rapid evolution of sex determination systems. Cardinium hertigii, a member of the Bacteroidetes and symbiont of the parasitic wasp Encarsia pergandiella, is the only known bacterium other than the Alphaproteobacteria Wolbachia to cause CI. Here we report the genome sequence of Cardinium hertigii cEper1. Comparison with the genomes of CI–inducing Wolbachia pipientis strains wMel, wRi, and wPip provides a unique opportunity to pinpoint shared proteins mediating host cell interaction, including some candidate proteins for CI that have not previously been investigated. The genome of Cardinium lacks all major biosynthetic pathways but harbors a complete biotin biosynthesis pathway, suggesting a potential role for Cardinium in host nutrition. Cardinium lacks known protein secretion systems but encodes a putative phage-derived secretion system distantly related to the antifeeding prophage of the entomopathogen Serratia entomophila. Lastly, while Cardinium and Wolbachia genomes show only a functional overlap of proteins, they show no evidence of laterally transferred elements that would suggest common ancestry of CI in both lineages. Instead, comparative genomics suggests an independent evolution of CI in Cardinium and Wolbachia and provides a novel context for understanding the mechanistic basis of CI. Many arthropods are infected with bacterial symbionts that are maternally transmitted and have a great impact on their hosts' biology, ecology, and evolution. One of the most common phenotypes of facultative symbionts appears to be cytoplasmic incompatibility (CI), a type of reproductive failure in which bacteria in males modify sperm in a way that reduces the reproductive success of uninfected female mates. In spite of considerable interest, the genetic basis for CI is largely unknown. Cardinium hertigii, a symbiont of tiny parasitic wasps, is the only bacterial group other than the well-studied Wolbachia that is known to cause CI. Analysis of the Cardinium genome indicates that CI evolved independently in Wolbachia and Cardinium. However, a suite of shared proteins was likely involved in mediating host cell interactions, and CI shows functional overlap in both lineages. Our analysis suggests the presence of an unusual phage-derived, putative secretion system and reveals that Cardinium encodes biosynthetic pathways that suggest a potential role in host nutrition. Our findings provide a novel comparative context for understanding the mechanistic basis of CI and substantially increase our knowledge on reproductive manipulator symbionts that do not only severely affect population genetic structure of arthropods but may also serve as powerful tools in pest management.
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Bertelli C, Greub G. Lateral gene exchanges shape the genomes of amoeba-resisting microorganisms. Front Cell Infect Microbiol 2012; 2:110. [PMID: 22919697 PMCID: PMC3423634 DOI: 10.3389/fcimb.2012.00110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 08/01/2012] [Indexed: 12/05/2022] Open
Abstract
Based on Darwin's concept of the tree of life, vertical inheritance was thought to be dominant, and mutations, deletions, and duplication were streaming the genomes of living organisms. In the current genomic era, increasing data indicated that both vertical and lateral gene inheritance interact in space and time to trigger genome evolution, particularly among microorganisms sharing a given ecological niche. As a paradigm to their diversity and their survival in a variety of cell types, intracellular microorganisms, and notably intracellular bacteria, were considered as less prone to lateral genetic exchanges. Such specialized microorganisms generally have a smaller gene repertoire because they do rely on their host's factors for some basic regulatory and metabolic functions. Here we review events of lateral gene transfer (LGT) that illustrate the genetic exchanges among intra-amoebal microorganisms or between the microorganism and its amoebal host. We tentatively investigate the functions of laterally transferred genes in the light of the interaction with their host as they should confer a selective advantage and success to the amoeba-resisting microorganisms (ARMs).
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Affiliation(s)
- Claire Bertelli
- Center for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Center and University of Lausanne Lausanne, Switzerland
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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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Applications of Fluorescence In Situ Hybridization in Diagnostic Microbiology. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Host-adapted bacteria include mutualists and pathogens of animals, plants and insects. Their study is therefore important for biotechnology, biodiversity and human health. The recent rapid expansion in bacterial genome data has provided insights into the adaptive, diversifying and reductive evolutionary processes that occur during host adaptation. The results have challenged many pre-existing concepts built from studies of laboratory bacterial strains. Furthermore, recent studies have revealed genetic changes associated with transitions from parasitism to mutualism and opened new research avenues to understand the functional reshaping of bacteria as they adapt to growth in the cytoplasm of a eukaryotic host.
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Barabote RD, Thekkiniath J, Strauss RE, Vediyappan G, Fralick JA, San Francisco MJ. Xenobiotic efflux in bacteria and fungi: a genomics update. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2011; 77:237-306. [PMID: 21692371 DOI: 10.1002/9780470920541.ch6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ravi D Barabote
- Department of Plant Sciences, University of California, Davis, California, USA
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Haider S, Wagner M, Schmid MC, Sixt BS, Christian JG, Häcker G, Pichler P, Mechtler K, Müller A, Baranyi C, Toenshoff ER, Montanaro J, Horn M. Raman microspectroscopy reveals long-term extracellular activity of Chlamydiae. Mol Microbiol 2010; 77:687-700. [PMID: 20545842 DOI: 10.1111/j.1365-2958.2010.07241.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The phylum Chlamydiae consists exclusively of obligate intracellular bacteria. Some of them are formidable pathogens of humans, while others occur as symbionts of amoebae. These genetically intractable bacteria possess a developmental cycle consisting of replicative reticulate bodies and infectious elementary bodies, which are believed to be physiologically inactive. Confocal Raman microspectroscopy was applied to differentiate between reticulate bodies and elementary bodies of Protochlamydia amoebophila and to demonstrate in situ the labelling of this amoeba symbiont after addition of isotope-labelled phenylalanine. Unexpectedly, uptake of this amino acid was also observed for both developmental stages for up to 3 weeks, if incubated extracellularly with labelled phenylalanine, and P. amoebophila remained infective during this period. Furthermore, P. amoebophila energizes its membrane and performs protein synthesis outside of its host. Importantly, amino acid uptake and protein synthesis after extended extracellular incubation could also be demonstrated for the human pathogen Chlamydia trachomatis, which synthesizes stress-related proteins under these conditions as shown by 2-D gel electrophoresis and MALDI-TOF/TOF mass spectrometry. These findings change our perception of chlamydial biology and reveal that host-free analyses possess a previously not recognized potential for direct experimental access to these elusive microorganisms.
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Affiliation(s)
- Susanne Haider
- Department of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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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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40
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Nikoh N, McCutcheon JP, Kudo T, Miyagishima SY, Moran NA, Nakabachi A. Bacterial genes in the aphid genome: absence of functional gene transfer from Buchnera to its host. PLoS Genet 2010; 6:e1000827. [PMID: 20195500 PMCID: PMC2829048 DOI: 10.1371/journal.pgen.1000827] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 12/21/2009] [Indexed: 01/18/2023] Open
Abstract
Genome reduction is typical of obligate symbionts. In cellular organelles, this reduction partly reflects transfer of ancestral bacterial genes to the host genome, but little is known about gene transfer in other obligate symbioses. Aphids harbor anciently acquired obligate mutualists, Buchnera aphidicola (Gammaproteobacteria), which have highly reduced genomes (420–650 kb), raising the possibility of gene transfer from ancestral Buchnera to the aphid genome. In addition, aphids often harbor other bacteria that also are potential sources of transferred genes. Previous limited sampling of genes expressed in bacteriocytes, the specialized cells that harbor Buchnera, revealed that aphids acquired at least two genes from bacteria. The newly sequenced genome of the pea aphid, Acyrthosiphon pisum, presents the first opportunity for a complete inventory of genes transferred from bacteria to the host genome in the context of an ancient obligate symbiosis. Computational screening of the entire A. pisum genome, followed by phylogenetic and experimental analyses, provided strong support for the transfer of 12 genes or gene fragments from bacteria to the aphid genome: three LD–carboxypeptidases (LdcA1, LdcA2,ψLdcA), five rare lipoprotein As (RlpA1-5), N-acetylmuramoyl-L-alanine amidase (AmiD), 1,4-beta-N-acetylmuramidase (bLys), DNA polymerase III alpha chain (ψDnaE), and ATP synthase delta chain (ψAtpH). Buchnera was the apparent source of two highly truncated pseudogenes (ψDnaE and ψAtpH). Most other transferred genes were closely related to genes from relatives of Wolbachia (Alphaproteobacteria). At least eight of the transferred genes (LdcA1, AmiD, RlpA1-5, bLys) appear to be functional, and expression of seven (LdcA1, AmiD, RlpA1-5) are highly upregulated in bacteriocytes. The LdcAs and RlpAs appear to have been duplicated after transfer. Our results excluded the hypothesis that genome reduction in Buchnera has been accompanied by gene transfer to the host nuclear genome, but suggest that aphids utilize a set of duplicated genes acquired from other bacteria in the context of the Buchnera–aphid mutualism. Bacterial lineages have repeatedly evolved intimate symbioses with eukaryotic hosts, the most famous cases being those of the cell organelles, mitochondria, and plastids. Symbiont genomes typically lose many ancestral genes, raising the question of how they function with so few genes. In organelles, part of the answer involves gene transfer to the host genome, allowing maintenance of essential functions. So far, the extent of gene transfer to hosts has not been assessed for other cases of intimate, obligate symbiosis. Aphids harbor an ancient coevolved intracellular symbiont, called Buchnera. We used the newly available sequence of the pea aphid genome to conduct an exhaustive computational search for genes of bacterial ancestry. We found that no functional genes have been transferred from Buchnera, ruling out such transfer as a driving force in genome reduction in this symbiont. However, the aphid genome does contain eight transcribed genes of apparent bacterial origin, some of which have been duplicated after transfer. Based on their expression patterns, most of these appear to function specifically in the aphid-Buchnera symbiosis, presenting the possibility that the maintenance of obligate intracellular symbioses can be affected by the acquisition and duplication of genes transferred from unrelated bacterial lineages.
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Affiliation(s)
- Naruo Nikoh
- Department of Liberal Arts, The Open University of Japan, Chiba, Japan
| | - John P. McCutcheon
- Center for Insect Science, University of Arizona, Tucson, Arizona, United States of America
| | - Toshiaki Kudo
- Discovery Research Institute, RIKEN, Wako, Saitama, Japan
| | | | - Nancy A. Moran
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America
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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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Felsheim RF, Kurtti TJ, Munderloh UG. Genome sequence of the endosymbiont Rickettsia peacockii and comparison with virulent Rickettsia rickettsii: identification of virulence factors. PLoS One 2009; 4:e8361. [PMID: 20027221 PMCID: PMC2791219 DOI: 10.1371/journal.pone.0008361] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 11/20/2009] [Indexed: 11/26/2022] Open
Abstract
Rickettsia peacockii, also known as the East Side Agent, is a non-pathogenic obligate intracellular bacterium found as an endosymbiont in Dermacentor andersoni ticks in the western USA and Canada. Its presence in ticks is correlated with reduced prevalence of Rickettsia rickettsii, the agent of Rocky Mountain Spotted Fever. It has been proposed that a virulent SFG rickettsia underwent changes to become the East Side Agent. We determined the genome sequence of R. peacockii and provide a comparison to a closely related virulent R. rickettsii. The presence of 42 chromosomal copies of the ISRpe1 transposon in the genome of R. peacockii is associated with a lack of synteny with the genome of R. rickettsii and numerous deletions via recombination between transposon copies. The plasmid contains a number of genes from distantly related organisms, such as part of the glycosylation island of Pseudomonas aeruginosa. Genes deleted or mutated in R. peacockii which may relate to loss of virulence include those coding for an ankyrin repeat containing protein, DsbA, RickA, protease II, OmpA, ScaI, and a putative phosphoethanolamine transferase. The gene coding for the ankyrin repeat containing protein is especially implicated as it is mutated in R. rickettsii strain Iowa, which has attenuated virulence. Presence of numerous copies of the ISRpe1 transposon, likely acquired by lateral transfer from a Cardinium species, are associated with extensive genomic reorganization and deletions. The deletion and mutation of genes possibly involved in loss of virulence have been identified by this genomic comparison. It also illustrates that the introduction of a transposon into the genome can have varied effects; either correlating with an increase in pathogenicity as in Francisella tularensis or a loss of pathogenicity as in R. peacockii and the recombination enabled by multiple transposon copies can cause significant deletions in some genomes while not in others.
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Affiliation(s)
- Roderick F. Felsheim
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Timothy J. Kurtti
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Ulrike G. Munderloh
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
- * E-mail:
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Choi SH, Cho MK, Ahn SC, Lee JE, Lee JS, Kim DH, Xuan YH, Hong YC, Kong HH, Chung DI, Yu HS. Endosymbionts of Acanthamoeba isolated from domestic tap water in Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2009; 47:337-44. [PMID: 19967080 DOI: 10.3347/kjp.2009.47.4.337] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 09/16/2009] [Accepted: 09/19/2009] [Indexed: 11/23/2022]
Abstract
In a previous study, we reported our discovery of Acanthamoeba contamination in domestic tap water; in that study, we determined that some Acanthamoeba strains harbor endosymbiotic bacteria, via our molecular characterization by mitochondrial DNA restriction fragment length polymorphism (Mt DNA RFLP). Five (29.4%) among 17 Acanthamoeba isolates contained endosymbionts in their cytoplasm, as demonstrated via orcein staining. In order to estimate their pathogenicity, we conducted a genetic characterization of the endosymbionts in Acanthamoeba isolated from domestic tap water via 16S rDNA sequencing. The endosymbionts of Acanthamoeba sp. KA/WP3 and KA/WP4 evidenced the highest level of similarity, at 97% of the recently published 16S rDNA sequence of the bacterium, Candidatus Amoebophilus asiaticus. The endosymbionts of Acanthamoeba sp. KA/WP8 and KA/WP12 shared a 97% sequence similarity with each other, and were also highly similar to Candidatus Odyssella thessalonicensis, a member of the alpha-proteobacteria. The endosymbiont of Acanthamoeba sp. KA/WP9 exhibits a high degree of similarity (85-95%) with genus Methylophilus, which is not yet known to harbor any endosymbionts. This is the first report, to the best of our knowledge, to show that Methylophilus spp. can live in the cytoplasm of Acanthamoeba.
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Affiliation(s)
- Seon Hee Choi
- Department of Parasitology, School of Medicine, Pusan National University, Busan, 602-739, Korea
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Prevalence of Cardinium bacteria in planthoppers and spider mites and taxonomic revision of "Candidatus Cardinium hertigii" based on detection of a new Cardinium group from biting midges. Appl Environ Microbiol 2009; 75:6757-63. [PMID: 19734338 DOI: 10.1128/aem.01583-09] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cardinium bacteria, members of the phylum Cytophaga-Flavobacterium-Bacteroides (CFB), are intracellular bacteria in arthropods that are capable of inducing reproductive abnormalities in their hosts, which include parasitic wasps, mites, and spiders. A high frequency of Cardinium infection was detected in planthoppers (27 out of 57 species were infected). A high frequency of Cardinium infection was also found in spider mites (9 out of 22 species were infected). Frequencies of double infection by Cardinium and Wolbachia bacteria (Alphaproteobacteria capable of manipulating reproduction of their hosts) were disproportionately high in planthoppers but not in spider mites. A new group of bacteria, phylogenetically closely related to but distinct from previously described Cardinium bacteria (based on 16S rRNA and gyrB genes) was found in 4 out of 25 species of Culicoides biting midges. These bacteria possessed a microfilament-like structure that is a morphological feature previously found in Cardinium and Paenicardinium. The bacteria close to the genus Cardinium consist of at least three groups, A, B, and C. Group A is present in various species of arthropods and was previously referred to as "Candidatus Cardinium hertigii," group B is present in plant parasitic nematodes and was previously referred to as "Candidatus Paenicardinium endonii," and group C is present in Culicoides biting midges. On the basis of morphological and molecular data, we propose that the nomenclature of these three groups be integrated into a single species, "Candidatus Cardinium hertigii."
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Moliner C, Raoult D, Fournier PE. Evidence that the intra-amoebal Legionella drancourtii acquired a sterol reductase gene from eukaryotes. BMC Res Notes 2009; 2:51. [PMID: 19327142 PMCID: PMC2667531 DOI: 10.1186/1756-0500-2-51] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 03/27/2009] [Indexed: 11/10/2022] Open
Abstract
Background Free-living amoebae serve as a natural reservoir for some bacteria that have evolved into «amoeba-resistant» bacteria. Among these, some are strictly intra-amoebal, such as Candidatus "Protochlamydia amoebophila" (Candidatus "P. amoebophila"), whose genomic sequence is available. We sequenced the genome of Legionella drancourtii (L. drancourtii), another recently described intra-amoebal bacterium. By comparing these two genomes with those of their closely related species, we were able to study the genetic characteristics specific to their amoebal lifestyle. Findings We identified a sterol delta-7 reductase-encoding gene common to these two bacteria and absent in their relatives. This gene encodes an enzyme which catalyses the last step of cholesterol biosynthesis in eukaryotes, and is probably functional within L. drancourtii since it is transcribed. The phylogenetic analysis of this protein suggests that it was acquired horizontally by a few bacteria from viridiplantae. This gene was also found in the Acanthamoeba polyphaga Mimivirus genome, a virus that grows in amoebae and possesses the largest viral genome known to date. Conclusion L. drancourtii acquired a sterol delta-7 reductase-encoding gene of viridiplantae origin. The most parsimonious hypothesis is that this gene was initially acquired by a Chlamydiales ancestor parasite of plants. Subsequently, its descendents transmitted this gene in amoebae to other intra-amoebal microorganisms, including L. drancourtii and Coxiella burnetii. The role of the sterol delta-7 reductase in prokaryotes is as yet unknown but we speculate that it is involved in host cholesterol parasitism.
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Affiliation(s)
- Claire Moliner
- URMITE CNRS-IRD UMR 6236, Faculté de Médecine, 27 boulevard Jean Moulin, 13385 Marseille, Cedex 05, France.
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47
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Affiliation(s)
- Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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48
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Abstract
Chlamydiae are important intracellular bacterial pathogens of vertebrates. In the last years, novel members of this group have been discovered: Parachlamydia acanthamoebae and Simkania negevensis seems to be emerging respiratory human pathogens, while Waddlia chondrophila might be a new agent of bovine abortion. Various species have been showed to infect also the herpetofauna and fishes, and some novel chlamydiae are endosymbionts of arthropods. In addition, molecular studies evidenced a huge diversity of chlamydiae from both environmental and clinical samples, most of such a diversity could be formed by novel lineages of chlamydiae. Experimental studies showed that free-living amoebae may support multiplication of various chlamydiae, then could play an important role as reservoir/vector of chlamydial infections. Here we reviewed literature data concerning chlamydial infections, with a particular emphasis on the novely described chlamydial organisms.
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Affiliation(s)
- Daniele Corsaro
- Retrovirology Laboratory, Centre Hospitalier de Luxembourg, Luxembourg
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49
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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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Duperron S, Halary S, Lorion J, Sibuet M, Gaill F. Unexpected co-occurrence of six bacterial symbionts in the gills of the cold seep mussel Idas sp. (Bivalvia: Mytilidae). Environ Microbiol 2008; 10:433-45. [DOI: 10.1111/j.1462-2920.2007.01465.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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