Metagenome of Free-Living Amoebae from Drinking water
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REPOSITORIES: ENA
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Project description:Isolation and characterization of free-living amoebae predating on Acinetobacter baumannii and Klebsiella pneumoniae
| PRJEB45300 | ENA
Project description:Legionella pneumophila are important opportunistic pathogens for which environmental reservoirs such as protists are crucial for the infection of humans. Free-living amoebae are considered key hosts providing nutrients and shelter for highly efficient intracellular proliferation of L. pneumophila, which eventually leads to lysis of the amoeba host cell. Yet, the significance of other bacterial players for L. pneumophila ecology is poorly understood. In this study we used a ubiquitous amoeba and their bacterial endosymbiont to investigate the impact of this common association on L. pneumophila infection. We demonstrate that Acanthamoeba castellanii harboring the chlamydial symbiont Protochlamydia amoebophila were able to erase L. pneumophila and, in contrast to symbiont-free amoebae, survived the infection and were able to resume growth. Environmental amoeba isolates harboring P. amoebophila were equally well-protected, and fresh environmental isolates of L. pneumophila were equally well-erased, suggesting ecological relevance of this symbiont-mediated protection. We further show that protection was not mediated by impaired L. pneumophila uptake. Instead, we observed reduced virulence of L. pneumophila released from symbiont-containing amoebae that is strongly supported by transcriptome data. Interference with transition to the transmissive phase is thus likely the basis for this protection. Finally, our data indicate that the defensive response of amoebae harboring P. amoebophila leaves the amoebae with superior fitness reminiscent of immunological memory. Given that mutualistic associations between bacteria and amoebae are widely distributed, P. amoebophila and potentially other amoeba endosymbionts could be key elements in shaping environmental survival, abundance and virulence of this important pathogen thereby affecting frequency of human infection.
2019-04-14 | GSE125876 | GEO
Project description:Intracellular growth of pathogenic Legionella in free-living amoebae (FLA) results in the critical concentrations that are problematic in engineered water systems (EWS). However, being amoeba-resistant bacteria (ARB), how Legionella spp. becomes internalized within FLA is still poorly understood. Using fluorescent microscopy, we investigated in real-time the preferential feeding behavior of three water-related FLA species, Willaertia magna, Acanthamoeba polyphaga, and Vermamoeba vermiformis regarding Legionella pneumophila and two Escherichia coli strains. Although all the studied FLA species supported intracellular growth of L. pneumophila, they avoided this bacterium to a certain degree in the presence of E. coli and mostly fed on it when the preferred bacterial food-sources were limited. Moreover, once L. pneumophila were intracellular, it inhibited digestion of co-occurring E. coli within the same trophozoites. Altogether, based on FLA-bacteria interactions and the shifts in microbial population dynamics, we propose that FLA's feeding preference leads to an initial growth of FLA and depletion of prey bacteria, thus increases the relative abundance of Legionella and creates a "forced-feeding" condition facilitating the internalization of Legionella into FLA to initiate the cycles of intracellular multiplication. These findings imply that monitoring of FLA levels in EWS could be useful in predicting possible imminent high occurrence of Legionella.
| S-EPMC7829821 | biostudies-literature
Project description:Transcriptional profiling of D. discoideum revealed sets of genes whose expression is enriched in amoebae interacting with different species of bacteria, including sets that appear specific to amoebae interacting with Gram(+), or with Gram(-) bacteria. In a genetic screen utilizing the growth of mutant amoebae on a variety of bacteria as a phenotypic readout, we identified amoebal genes that are only required for growth on Gram(+) bacteria, including one that encodes the cell surface protein gp130, as well as several genes that are only required for growth on Gram(-) bacteria including one that encodes a putative lysozyme, AlyL. These genes are required for parts of the transcriptional response of wild-type amoebae, and this allowed their classification into potential response pathways.
2013-05-20 | GSE46386 | GEO
Project description:We report the transcriptome of M. abscessus in amoebae and macrophages. M. abscessus intra-amoebal and intra-macrophagic transcriptomes demonstrate of the potential of M. abscessus to adapt to an intracellular lifestyle, though amoebae largely contribute to the enhancement of M. abscessus survival macrophages.
2019-09-20 | GSE124972 | GEO
Project description:To further development of our gene expression approch to intracellular pathogenic bacterial controlling, we have employed castamized Neochlamydia S13 genomic microarray as a discovery platform to identy genes with the potential to inhibit Legionella growth into hoat amoebae , based on our data that the the amoebae haboring amoebal endosymbiont Neochlamydia S13 (an environmental chlamydia) could evade Legionella infection.
2014-12-31 | GSE54012 | GEO
Project description:Infection with pathogenic free-living amoebae, including Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris, can lead to life-threatening illnesses, primarily because of catastrophic central nervous system involvement. Efficacious treatment options for these infections are lacking, and the mortality rate due to infection is high. Previously, we evaluated the N. fowleri glucokinase (NfGlck) as a potential target for therapeutic intervention, as glucose metabolism is critical for in vitro viability. Here, we extended these studies to the glucokinases from two other pathogenic free-living amoebae, including Acanthamoeba castellanii (AcGlck) and B. mandrillaris (BmGlck). While these enzymes are similar (49.3% identical at the amino acid level), they have distinct kinetic properties that distinguish them from each other. For ATP, AcGlck and BmGlck have apparent Km values of 472.5 and 41.0 μM, while Homo sapiens Glck (HsGlck) has a value of 310 μM. Both parasite enzymes also have a higher apparent affinity for glucose than the human counterpart, with apparent Km values of 45.9 μM (AcGlck) and 124 μM (BmGlck) compared to ~8 mM for HsGlck. Additionally, AcGlck and BmGlck differ from each other and other Glcks in their sensitivity to small molecule inhibitors, suggesting that inhibitors with pan-amoebic activity could be challenging to generate.
| S-EPMC9211422 | biostudies-literature
Project description:Transcriptional profiling of D. discoideum revealed sets of genes whose expression is enriched in amoebae interacting with different species of bacteria, including sets that appear specific to amoebae interacting with Gram(+), or with Gram(-) bacteria. In a genetic screen utilizing the growth of mutant amoebae on a variety of bacteria as a phenotypic readout, we identified amoebal genes that are only required for growth on Gram(+) bacteria, including one that encodes the cell surface protein gp130, as well as several genes that are only required for growth on Gram(-) bacteria including one that encodes a putative lysozyme, AlyL. These genes are required for parts of the transcriptional response of wild-type amoebae, and this allowed their classification into potential response pathways. Transcriptional profiling of amoebal response to different bacteria.
2013-05-20 | E-GEOD-46386 | biostudies-arrayexpress
Project description:Mycobacterium avium subsp. paratuberculosis is responsible for paratuberculosis in animals. This disease, leading to an inflammation of the gastrointestinal tract, has a high impact on animal health and an important economic burden. The environmental life cycle of M. avium subsp. paratuberculosis is poorly understood and several studies suggest that free-living amoebae (FLA) might be a potential environmental host. FLA are protozoa found in water and soil that are described as reservoirs of pathogenic and non-pathogenic bacteria in the environment. Indeed, bacteria able to survive within these amoebae would survive phagocytosis from immune cells. In this study, we assessed the in vitro interactions between several strains of M. avium subsp. paratuberculosis and Acanthamoeba castellanii. The results indicate that the bacteria were able to grow within the amoeba and that they can survive for several days within their host. To explore the presence of M. avium subsp. paratuberculosis in environmental amoebae, we sampled water from farms positive for paratuberculosis. A M. avium subsp. paratuberculosis strain was detected within an environmental amoeba identified as related to the poorly described Rosculus genus. The bacterial strain was genotyped, showing that it was similar to previous infectious strains isolated from cattle. In conclusion, we described that various M. avium subsp. paratuberculosis strains were able to grow within amoebae and that these bacteria could be found on farm within amoebae isolated from the cattle environment. It validates that infected amoebae might be a reservoir and vector for the transmission of M. avium subsp. paratuberculosis.
| S-EPMC5811464 | biostudies-literature
Project description:Legionella pneumophila is known as the causative agent of Legionnaires' disease and free-living amoebae (FLA) can serve as vehicles for legionellae. The aim of this study was to screen industrial waters for the occurrence of FLA and their co-occurrence with legionellae. A total of 201 water samples, including 129 cooling waters and 72 process waters, and 30 cooling lubricants were included in the study. Treated waters were screened periodically, pre and post treatment. Altogether, 72.6% of the water samples were positive for FLA, acanthamoebae being most prevalent (in 23.9% of the samples) followed by Vermamoeba vermiformis (19.4%). Only one cooling lubricant was positive (Acanthamoeba genotype T4). Legionella spp. were detected in 34.8% of the water samples and in 15% in high concentrations (>1000 CFU/100 ml). Altogether, 81.4% of the Legionella-positive samples were positive for FLA by standard methods. By applying a highly sensitive nested PCR to a representative set of random samples it was revealed that Legionella spp. always co-occurred with Acanthamoeba spp. Although the addition of disinfectants did influence amoebal density and diversity, treated waters showed no difference concerning FLA in the interphases of disinfection. It appears that FLA can re-colonize treated waters within a short period of time.
| S-EPMC4155075 | biostudies-literature