Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)

ABSTRACT Metagenome-assembled genomes (MAGs) of Asgardarchaeota have been recovered from a variety of habitats, broadening their environmental distribution and providing access to the genetic makeup of this archaeal lineage. The recent success in cultivating the first representative of Lokiarchaeia...

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Main Authors: Michaela M. Salcher, Adrian-Ştefan Andrei, Paul-Adrian Bulzu, Zsolt G. Keresztes, Horia L. Banciu, Rohit Ghai
Format: Article
Language:English
Published: American Society for Microbiology 2020-08-01
Series:mSphere
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/mSphere.00686-20
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author Michaela M. Salcher
Adrian-Ştefan Andrei
Paul-Adrian Bulzu
Zsolt G. Keresztes
Horia L. Banciu
Rohit Ghai
author_facet Michaela M. Salcher
Adrian-Ştefan Andrei
Paul-Adrian Bulzu
Zsolt G. Keresztes
Horia L. Banciu
Rohit Ghai
author_sort Michaela M. Salcher
collection DOAJ
description ABSTRACT Metagenome-assembled genomes (MAGs) of Asgardarchaeota have been recovered from a variety of habitats, broadening their environmental distribution and providing access to the genetic makeup of this archaeal lineage. The recent success in cultivating the first representative of Lokiarchaeia was a breakthrough in science at large and gave rise to new hypotheses about the evolution of eukaryotes. Despite their singular phylogenetic position at the base of the eukaryotic tree of life, the morphology of these bewildering organisms remains a mystery, except for the report of an unusual morphology with long, branching protrusions of the cultivated Lokiarchaeion strain “Candidatus Prometheoarchaeum syntrophicum” MK-D1. In order to visualize this elusive group, we applied a combination of fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH) and epifluorescence microscopy on coastal hypersaline sediment samples, using specifically designed CARD-FISH probes for Heimdallarchaeia and Lokiarchaeia lineages, and provide the first visual evidence for Heimdallarchaeia and new images of a lineage of Lokiarchaeia that is different from the cultured representative. Here, we show that while Heimdallarchaeia are characterized by a uniform cellular morphology typified by a centralized DNA localization, Lokiarchaeia display a plethora of shapes and sizes that likely reflect their broad phylogenetic diversity and ecological distribution. IMPORTANCE Asgardarchaeota are considered to be the closest relatives to modern eukaryotes. These enigmatic microbes have been mainly studied using metagenome-assembled genomes (MAGs). Only very recently, a first member of Lokiarchaeia was isolated and characterized in detail; it featured a striking morphology with long, branching protrusions. In order to visualize additional members of the phylum Asgardarchaeota, we applied a fluorescence in situ hybridization technique and epifluorescence microscopy on coastal hypersaline sediment samples, using specifically designed probes for Heimdallarchaeia and Lokiarchaeia lineages. We provide the first visual evidence for Heimdallarchaeia that are characterized by a uniform cellular morphology typified by an apparently centralized DNA localization. Further, we provide new images of a lineage of Lokiarchaeia that is different from the cultured representative and with multiple morphologies, ranging from small ovoid cells to long filaments. This diversity in observed cell shapes is likely owing to the large phylogenetic diversity within Asgardarchaeota, the vast majority of which remain uncultured.
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spelling doaj.art-48cae9d2156646e782b5bbacba5ac3312022-12-21T20:07:27ZengAmerican Society for MicrobiologymSphere2379-50422020-08-015410.1128/mSphere.00686-20Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)Michaela M. Salcher0Adrian-Ştefan Andrei1Paul-Adrian Bulzu2Zsolt G. Keresztes3Horia L. Banciu4Rohit Ghai5Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech RepublicDepartment of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech RepublicDepartment of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech RepublicDepartment of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, Cluj-Napoca, RomaniaDepartment of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, Cluj-Napoca, RomaniaDepartment of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech RepublicABSTRACT Metagenome-assembled genomes (MAGs) of Asgardarchaeota have been recovered from a variety of habitats, broadening their environmental distribution and providing access to the genetic makeup of this archaeal lineage. The recent success in cultivating the first representative of Lokiarchaeia was a breakthrough in science at large and gave rise to new hypotheses about the evolution of eukaryotes. Despite their singular phylogenetic position at the base of the eukaryotic tree of life, the morphology of these bewildering organisms remains a mystery, except for the report of an unusual morphology with long, branching protrusions of the cultivated Lokiarchaeion strain “Candidatus Prometheoarchaeum syntrophicum” MK-D1. In order to visualize this elusive group, we applied a combination of fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH) and epifluorescence microscopy on coastal hypersaline sediment samples, using specifically designed CARD-FISH probes for Heimdallarchaeia and Lokiarchaeia lineages, and provide the first visual evidence for Heimdallarchaeia and new images of a lineage of Lokiarchaeia that is different from the cultured representative. Here, we show that while Heimdallarchaeia are characterized by a uniform cellular morphology typified by a centralized DNA localization, Lokiarchaeia display a plethora of shapes and sizes that likely reflect their broad phylogenetic diversity and ecological distribution. IMPORTANCE Asgardarchaeota are considered to be the closest relatives to modern eukaryotes. These enigmatic microbes have been mainly studied using metagenome-assembled genomes (MAGs). Only very recently, a first member of Lokiarchaeia was isolated and characterized in detail; it featured a striking morphology with long, branching protrusions. In order to visualize additional members of the phylum Asgardarchaeota, we applied a fluorescence in situ hybridization technique and epifluorescence microscopy on coastal hypersaline sediment samples, using specifically designed probes for Heimdallarchaeia and Lokiarchaeia lineages. We provide the first visual evidence for Heimdallarchaeia that are characterized by a uniform cellular morphology typified by an apparently centralized DNA localization. Further, we provide new images of a lineage of Lokiarchaeia that is different from the cultured representative and with multiple morphologies, ranging from small ovoid cells to long filaments. This diversity in observed cell shapes is likely owing to the large phylogenetic diversity within Asgardarchaeota, the vast majority of which remain uncultured.https://journals.asm.org/doi/10.1128/mSphere.00686-20AsgardarchaeotaHeimdallarchaeiaLokiarchaeiaCARD-FISHmorphology
spellingShingle Michaela M. Salcher
Adrian-Ştefan Andrei
Paul-Adrian Bulzu
Zsolt G. Keresztes
Horia L. Banciu
Rohit Ghai
Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
mSphere
Asgardarchaeota
Heimdallarchaeia
Lokiarchaeia
CARD-FISH
morphology
title Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
title_full Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
title_fullStr Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
title_full_unstemmed Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
title_short Visualization of Lokiarchaeia and Heimdallarchaeia (Asgardarchaeota) by Fluorescence <italic toggle="yes">In Situ</italic> Hybridization and Catalyzed Reporter Deposition (CARD-FISH)
title_sort visualization of lokiarchaeia and heimdallarchaeia asgardarchaeota by fluorescence italic toggle yes in situ italic hybridization and catalyzed reporter deposition card fish
topic Asgardarchaeota
Heimdallarchaeia
Lokiarchaeia
CARD-FISH
morphology
url https://journals.asm.org/doi/10.1128/mSphere.00686-20
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