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Conservation of Genomic Information in Multiple Displacement Amplified Low-Quantity Metagenomic Material from Marine Invertebrates. Mar Drugs 2023; 21:md21030165. [PMID: 36976214 PMCID: PMC10054348 DOI: 10.3390/md21030165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Marine invertebrate microbiomes have been a rich source of bioactive compounds and interesting genomic features. In cases where the achievable amounts of metagenomic DNA are too low for direct sequencing, multiple displacement amplification (MDA) can be used for whole genome amplification. However, MDA has known limitations which can affect the quality of the resulting genomes and metagenomes. In this study, we evaluated the conservation of biosynthetic gene clusters (BGCs) and enzymes in MDA products from low numbers of prokaryotic cells (estimated 2–850). Marine invertebrate microbiomes collected from Arctic and sub-Arctic areas served as source material. The cells were separated from the host tissue, lysed, and directly subjected to MDA. The MDA products were sequenced by Illumina sequencing. Corresponding numbers of bacteria from a set of three reference strains were treated the same way. The study demonstrated that useful information on taxonomic, BGC, and enzyme diversities was obtainable from such marginal quantities of metagenomic material. Although high levels of assembly fragmentation resulted in most BGCs being incomplete, we conclude that this genome mining approach has the potential to reveal interesting BGCs and genes from hard-to-reach biological sources.
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Cerqueira de Araujo A, Josse T, Sibut V, Urabe M, Asadullah A, Barbe V, Nakai M, Huguet E, Periquet G, Drezen JM. Chelonus inanitus bracovirus encodes lineage-specific proteins and truncated immune IκB-like factors. J Gen Virol 2022; 103. [DOI: 10.1099/jgv.0.001791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bracoviruses and ichnoviruses are endogenous viruses of parasitic wasps that produce particles containing virulence genes expressed in host tissues and necessary for parasitism success. In the case of bracoviruses the particles are produced by conserved genes of nudiviral origin integrated permanently in the wasp genome, whereas the virulence genes can strikingly differ depending on the wasp lineage. To date most data obtained on bracoviruses concerned species from the braconid subfamily of Microgastrinae. To gain a broader view on the diversity of virulence genes we sequenced the genome packaged in the particles of Chelonus inanitus bracovirus (CiBV) produced by a wasp belonging to a different subfamily: the Cheloninae. These are egg-larval parasitoids, which means that they oviposit into the host egg and the wasp larvae then develop within the larval stages of the host. We found that most of CiBV virulence genes belong to families that are specific to Cheloninae. As other bracoviruses and ichnoviruses however, CiBV encode v-ank genes encoding truncated versions of the immune cactus/IκB factor, which suggests these proteins might play a key role in host–parasite interactions involving domesticated endogenous viruses. We found that the structures of CiBV V-ANKs are different from those previously reported. Phylogenetic analysis supports the hypothesis that they may originate from a cactus/IκB immune gene from the wasp genome acquired by the bracovirus. However, their evolutionary history is different from that shared by other V-ANKs, whose common origin probably reflects horizontal gene transfer events of virus sequences between braconid and ichneumonid wasps.
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Affiliation(s)
| | - Thibaut Josse
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France
| | - Vonick Sibut
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France
| | - Mariko Urabe
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Azam Asadullah
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Valérie Barbe
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
| | - Madoka Nakai
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Elisabeth Huguet
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France
| | - Georges Periquet
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France
| | - Jean-Michel Drezen
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France
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Bowers RM, Nayfach S, Schulz F, Jungbluth SP, Ruhl IA, Sheremet A, Lee J, Goudeau D, Eloe-Fadrosh EA, Stepanauskas R, Malmstrom RR, Kyrpides NC, Dunfield PF, Woyke T. Dissecting the dominant hot spring microbial populations based on community-wide sampling at single-cell genomic resolution. THE ISME JOURNAL 2022; 16:1337-1347. [PMID: 34969995 PMCID: PMC9039060 DOI: 10.1038/s41396-021-01178-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/29/2021] [Accepted: 12/10/2021] [Indexed: 02/07/2023]
Abstract
With advances in DNA sequencing and miniaturized molecular biology workflows, rapid and affordable sequencing of single-cell genomes has become a reality. Compared to 16S rRNA gene surveys and shotgun metagenomics, large-scale application of single-cell genomics to whole microbial communities provides an integrated snapshot of community composition and function, directly links mobile elements to their hosts, and enables analysis of population heterogeneity of the dominant community members. To that end, we sequenced nearly 500 single-cell genomes from a low diversity hot spring sediment sample from Dewar Creek, British Columbia, and compared this approach to 16S rRNA gene amplicon and shotgun metagenomics applied to the same sample. We found that the broad taxonomic profiles were similar across the three sequencing approaches, though several lineages were missing from the 16S rRNA gene amplicon dataset, likely the result of primer mismatches. At the functional level, we detected a large array of mobile genetic elements present in the single-cell genomes but absent from the corresponding same species metagenome-assembled genomes. Moreover, we performed a single-cell population genomic analysis of the three most abundant community members, revealing differences in population structure based on mutation and recombination profiles. While the average pairwise nucleotide identities were similar across the dominant species-level lineages, we observed differences in the extent of recombination between these dominant populations. Most intriguingly, the creek's Hydrogenobacter sp. population appeared to be so recombinogenic that it more closely resembled a sexual species than a clonally evolving microbe. Together, this work demonstrates that a randomized single-cell approach can be useful for the exploration of previously uncultivated microbes from community composition to population structure.
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Affiliation(s)
- Robert M. Bowers
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Stephen Nayfach
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Frederik Schulz
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Sean P. Jungbluth
- grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Ilona A. Ruhl
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada ,grid.419357.d0000 0001 2199 3636National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Andriy Sheremet
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
| | - Janey Lee
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Danielle Goudeau
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Emiley A. Eloe-Fadrosh
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Ramunas Stepanauskas
- grid.296275.d0000 0000 9516 4913Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, ME USA
| | - Rex R. Malmstrom
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Nikos C. Kyrpides
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Peter F. Dunfield
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
| | - Tanja Woyke
- U.S. Department of Energy, Joint Genome Institute, Berkeley, CA, USA.
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4
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Genome sequencing and de novo assembly of the giant unicellular alga Acetabularia acetabulum using droplet MDA. Sci Rep 2021; 11:12820. [PMID: 34140556 PMCID: PMC8211769 DOI: 10.1038/s41598-021-92092-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 05/28/2021] [Indexed: 11/08/2022] Open
Abstract
The macroscopic single-celled green alga Acetabularia acetabulum has been a model system in cell biology for more than a century. However, no genomic information is available from this species. Since the alga has a long life cycle, is difficult to grow in dense cultures, and has an estimated diploid genome size of almost 2 Gb, obtaining sufficient genomic material for genome sequencing is challenging. Here, we have attempted to overcome these challenges by amplifying genomic DNA using multiple displacement amplification (MDA) combined with microfluidics technology to distribute the amplification reactions across thousands of microscopic droplets. By amplifying and sequencing DNA from five single cells we were able to recover an estimated ~ 7–11% of the total genome, providing the first draft of the A. acetabulum genome. We highlight challenges associated with genome recovery and assembly of MDA data due to biases arising during genome amplification, and hope that our study can serve as a reference for future attempts on sequencing the genome from non-model eukaryotes.
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Ciobanu D, Clum A, Ahrendt S, Andreopoulos WB, Salamov A, Chan S, Quandt CA, Foster B, Meier-Kolthoff JP, Tang YT, Schwientek P, Benny GL, Smith ME, Bauer D, Deshpande S, Barry K, Copeland A, Singer SW, Woyke T, Grigoriev IV, James TY, Cheng JF. A single-cell genomics pipeline for environmental microbial eukaryotes. iScience 2021; 24:102290. [PMID: 33870123 PMCID: PMC8042348 DOI: 10.1016/j.isci.2021.102290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/12/2021] [Accepted: 03/04/2021] [Indexed: 12/05/2022] Open
Abstract
Single-cell sequencing of environmental microorganisms is an essential component of the microbial ecology toolkit. However, large-scale targeted single-cell sequencing for the whole-genome recovery of uncultivated eukaryotes is lagging. The key challenges are low abundance in environmental communities, large complex genomes, and cell walls that are difficult to break. We describe a pipeline composed of state-of-the art single-cell genomics tools and protocols optimized for poorly studied and uncultivated eukaryotic microorganisms that are found at low abundance. This pipeline consists of seven distinct steps, beginning with sample collection and ending with genome annotation, each equipped with quality review steps to ensure high genome quality at low cost. We tested and evaluated each step on environmental samples and cultures of early-diverging lineages of fungi and Chromista/SAR. We show that genomes produced using this pipeline are almost as good as complete reference genomes for functional and comparative genomics for environmental microbial eukaryotes.
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Affiliation(s)
- Doina Ciobanu
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Steven Ahrendt
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - William B. Andreopoulos
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Sandy Chan
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - C. Alisha Quandt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brian Foster
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Jan P. Meier-Kolthoff
- Department of Bioinformatics and Databases, Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Inhoffenstrasse 7B, 38124 Braunschweig, Germany
| | - Yung Tsu Tang
- Joint BioEnergy Institute, Emeryville, CA 94608, USA
| | - Patrick Schwientek
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Gerald L. Benny
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Matthew E. Smith
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Diane Bauer
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Shweta Deshpande
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Alex Copeland
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | | | - Tanja Woyke
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Timothy Y. James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jan-Fang Cheng
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory Berkeley, Berkeley, CA, USA
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Regnault B, Bigot T, Ma L, Pérot P, Temmam S, Eloit M. Deep Impact of Random Amplification and Library Construction Methods on Viral Metagenomics Results. Viruses 2021; 13:v13020253. [PMID: 33562285 PMCID: PMC7915491 DOI: 10.3390/v13020253] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 12/16/2022] Open
Abstract
Clinical metagenomics is a broad-range agnostic detection method of pathogens, including novel microorganisms. A major limit is the low pathogen load compared to the high background of host nucleic acids. To overcome this issue, several solutions exist, such as applying a very high depth of sequencing, or performing a relative enrichment of viral genomes associated with capsids. At the end, the quantity of total nucleic acids is often below the concentrations recommended by the manufacturers of library kits, which necessitates to random amplify nucleic acids. Using a pool of 26 viruses representative of viral diversity, we observed a deep impact of the nature of sample (total nucleic acids versus RNA only), the reverse transcription, the random amplification and library construction method on virus recovery. We further optimized the two most promising methods and assessed their performance with fully characterized reference virus stocks. Good genome coverage and limit of detection lower than 100 or 1000 genome copies per mL of plasma, depending on the genome viral type, were obtained from a three million reads dataset. Our study reveals that optimized random amplification is a technique of choice when insufficient amounts of nucleic acid are available for direct libraries constructions.
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Affiliation(s)
- Béatrice Regnault
- Pathogen Discovery Laboratory, Institut Pasteur, 75015 Paris, France; (B.R.); (P.P.); (S.T.)
| | - Thomas Bigot
- Bioinformatics and Biostatistics Hub, Computational Biology Department, Institut Pasteur, 75015 Paris, France;
| | - Laurence Ma
- Biomics Platform, C2RT, Institut Pasteur, 75015 Paris, France;
| | - Philippe Pérot
- Pathogen Discovery Laboratory, Institut Pasteur, 75015 Paris, France; (B.R.); (P.P.); (S.T.)
| | - Sarah Temmam
- Pathogen Discovery Laboratory, Institut Pasteur, 75015 Paris, France; (B.R.); (P.P.); (S.T.)
| | - Marc Eloit
- Pathogen Discovery Laboratory, Institut Pasteur, 75015 Paris, France; (B.R.); (P.P.); (S.T.)
- Ecole Nationale Vétérinaire d’Alfort, 94700 Maisons-Alfort, France
- Correspondence: ; Tel.: +33-1-44-38-92-16
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Campbell EO, Dupuis JR, Holowachuk J, Hladun S, Vankosky MA, Mori BA. Disjunction between canola distribution and the genetic structure of its recently described pest, the canola flower midge ( Contarinia brassicola). Ecol Evol 2020; 10:13284-13296. [PMID: 33304537 PMCID: PMC7713945 DOI: 10.1002/ece3.6927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/10/2020] [Accepted: 09/07/2020] [Indexed: 12/31/2022] Open
Abstract
Population genomics is a useful tool to support integrated pest management as it can elucidate population dynamics, demography, and histories of invasion. Here, we use a restriction site-associated DNA sequencing approach combined with whole-genome amplification (WGA) to assess genomic population structure of a newly described pest of canola, the diminutive canola flower midge, Contarinia brassicola. Clustering analyses recovered little geographic structure across the main canola production region but differentiated several geographically disparate populations at edges of the agricultural zone. Given a lack of alternative hypotheses for this pattern, we suggest these data support alternative hosts for this species and thus our canola-centric view of this midge as a pest has limited our understanding of its biology. These results speak to the need for increased surveying efforts across multiple habitats and other potential hosts within Brassicaceae to improve both our ecological and evolutionary knowledge of this species and contribute to effective management strategies. We additionally found that use of WGA prior to library preparation was an effective method for increasing DNA quantity of these small insects prior to restriction site-associated DNA sequencing and had no discernible impact on genotyping consistency for population genetic analysis; WGA is therefore likely to be tractable for other similar studies that seek to randomly sample markers across the genome in small organisms.
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Affiliation(s)
- Erin O. Campbell
- Department of Agriculture, Food, and Nutrition Sciences4‐10 Agriculture/Forestry CentreUniversity of AlbertaEdmontonABCanada
| | | | - Jennifer Holowachuk
- Agriculture and Agri‐Food CanadaSaskatoon Research and Development CentreSaskatoonSKCanada
| | - Shane Hladun
- Agriculture and Agri‐Food CanadaSaskatoon Research and Development CentreSaskatoonSKCanada
| | - Meghan A. Vankosky
- Agriculture and Agri‐Food CanadaSaskatoon Research and Development CentreSaskatoonSKCanada
| | - Boyd A. Mori
- Department of Agriculture, Food, and Nutrition Sciences4‐10 Agriculture/Forestry CentreUniversity of AlbertaEdmontonABCanada
- Agriculture and Agri‐Food CanadaSaskatoon Research and Development CentreSaskatoonSKCanada
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8
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Dhorne-Pollet S, Barrey E, Pollet N. A new method for long-read sequencing of animal mitochondrial genomes: application to the identification of equine mitochondrial DNA variants. BMC Genomics 2020; 21:785. [PMID: 33176683 PMCID: PMC7661214 DOI: 10.1186/s12864-020-07183-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 10/26/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mitochondrial DNA is remarkably polymorphic. This is why animal geneticists survey mitochondrial genomes variations for fundamental and applied purposes. We present here an approach to sequence whole mitochondrial genomes using nanopore long-read sequencing. Our method relies on the selective elimination of nuclear DNA using an exonuclease treatment and on the amplification of circular mitochondrial DNA using a multiple displacement amplification step. RESULTS We optimized each preparative step to obtain a 100 million-fold enrichment of horse mitochondrial DNA relative to nuclear DNA. We sequenced these amplified mitochondrial DNA using nanopore sequencing technology and obtained mitochondrial DNA reads that represented up to half of the sequencing output. The sequence reads were 2.3 kb of mean length and provided an even coverage of the mitochondrial genome. Long-reads spanning half or more of the whole mtDNA provided a coverage that varied between 118X and 488X. We evaluated SNPs identified using these long-reads by Sanger sequencing as ground truth and found a precision of 100.0%; a recall of 93.1% and a F1-score of 0.964 using the Twilight horse mtDNA reference. The choice of the mtDNA reference impacted variant calling efficiency with F1-scores varying between 0.947 and 0.964. CONCLUSIONS Our method to amplify mtDNA and to sequence it using the nanopore technology is usable for mitochondrial DNA variant analysis. With minor modifications, this approach could easily be applied to other large circular DNA molecules.
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Affiliation(s)
- Sophie Dhorne-Pollet
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Eric Barrey
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Nicolas Pollet
- Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, 91198, Gif-sur-Yvette, France.
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Kooyman FNJ, Wagenaar JA, Zomer A. Whole-genome sequencing of dog-specific assemblages C and D of Giardia duodenalis from single and pooled cysts indicates host-associated genes. Microb Genom 2020; 5. [PMID: 31821130 PMCID: PMC6939161 DOI: 10.1099/mgen.0.000302] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Giardia duodenalis (syn. Giardia intestinalis or Giardia lamblia) infSAects over 280 million people each year and numerous animals. G. duodenalis can be subdivided into eight assemblages with different host specificity. Unculturable assemblages have so far resisted genome sequencing efforts. In this study, we isolated single and pooled cysts of assemblages C and D from dog faeces by FACS, and sequenced them using multiple displacement amplification and Illumina paired-end sequencing. The genomes of assemblages C and D were compared with genomes of assemblages A and B from humans and assemblage E from ruminants and pigs. The genomes obtained from the pooled cysts and from the single cysts were considered complete (>99 % marker genes observed) and the allelic sequence heterozygosity (ASH) values of assemblages C and D were 0.89 and 0.74 %, respectively. These ASH values were slightly higher than for assemblage B (>0.43 %) and much higher than for assemblages A and E, which ranged from 0.002 to 0.037 %. The flavohaemoglobin and 4Fe-4S binding domain family encoding genes involved in O2 and NO detoxification were only present in assemblages A, B and E. Cathepsin B orthologs were found in all genomes. Six clades of cathepsin B orthologs contained one gene of each genome, while in three clades not all assemblages were represented. We conclude that whole-genome sequencing from a single Giardia cyst results in complete draft genomes, making the genomes of unculturable Giardia assemblages accessible. Observed differences between the genomes of assemblages C and D on one hand and the assemblages A, B and E on the other hand are possibly associated with host specificity.
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Affiliation(s)
- Frans N. J. Kooyman
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- *Correspondence: Frans N. J. Kooyman,
| | - Jaap A. Wagenaar
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Aldert Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Parras-Moltó M, Rodríguez-Galet A, Suárez-Rodríguez P, López-Bueno A. Evaluation of bias induced by viral enrichment and random amplification protocols in metagenomic surveys of saliva DNA viruses. MICROBIOME 2018; 6:119. [PMID: 29954453 PMCID: PMC6022446 DOI: 10.1186/s40168-018-0507-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/19/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND Viruses are key players regulating microbial ecosystems. Exploration of viral assemblages is now possible thanks to the development of metagenomics, the most powerful tool available for studying viral ecology and discovering new viruses. Unfortunately, several sources of bias lead to the misrepresentation of certain viruses within metagenomics workflows, hindering the shift from merely descriptive studies towards quantitative comparisons of communities. Therefore, benchmark studies on virus enrichment and random amplification protocols are required to better understand the sources of bias. RESULTS We assessed the bias introduced by viral enrichment on mock assemblages composed of seven DNA viruses, and the bias from random amplification methods on human saliva DNA viromes, using qPCR and deep sequencing, respectively. While iodixanol cushions and 0.45 μm filtration preserved the original composition of nuclease-protected viral genomes, low-force centrifugation and 0.22 μm filtration removed large viruses. Comparison of unamplified and randomly amplified saliva viromes revealed that multiple displacement amplification (MDA) induced stochastic bias from picograms of DNA template. However, the type of bias shifted to systematic using 1 ng, with only a marginal influence by amplification time. Systematic bias consisted of over-amplification of small circular genomes, and under-amplification of those with extreme GC content, a negative bias that was shared with the PCR-based sequence-independent, single-primer amplification (SISPA) method. MDA based on random priming provided by a DNA primase activity slightly outperformed those based on random hexamers and SISPA, which may reflect differences in ability to handle sequences with extreme GC content. SISPA viromes showed uneven coverage profiles, with high coverage peaks in regions with low linguistic sequence complexity. Despite misrepresentation of certain viruses after random amplification, ordination plots based on dissimilarities among contig profiles showed perfect overlapping of related amplified and unamplified saliva viromes and strong separation from unrelated saliva viromes. This result suggests that random amplification bias has a minor impact on beta diversity studies. CONCLUSIONS Benchmark analyses of mock and natural communities of viruses improve understanding and mitigate bias in metagenomics surveys. Bias induced by random amplification methods has only a minor impact on beta diversity studies of human saliva viromes.
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Affiliation(s)
- Marcos Parras-Moltó
- Centro de Biología Molecular Severo Ochoa (Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Ana Rodríguez-Galet
- Centro de Biología Molecular Severo Ochoa (Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Patricia Suárez-Rodríguez
- Centro de Biología Molecular Severo Ochoa (Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Alberto López-Bueno
- Centro de Biología Molecular Severo Ochoa (Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas), Madrid, Spain.
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11
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Kang I, Kim S, Islam MR, Cho JC. The first complete genome sequences of the acI lineage, the most abundant freshwater Actinobacteria, obtained by whole-genome-amplification of dilution-to-extinction cultures. Sci Rep 2017; 7:42252. [PMID: 28186143 PMCID: PMC5301498 DOI: 10.1038/srep42252] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 01/06/2017] [Indexed: 02/07/2023] Open
Abstract
The acI lineage of the phylum Actinobacteria is the most abundant bacterial group in most freshwater lakes. However, due to difficulties in laboratory cultivation, only two mixed cultures and some incomplete single-amplified or metagenome-derived genomes have been reported for the lineage. Here, we report the initial cultivation and complete genome sequences of four novel strains of the acI lineage from the tribes acI-A1, -A4, -A7, and -C1. The acI strains, initially isolated by dilution-to-extinction culturing, eventually failed to be maintained as axenic cultures. However, the first complete genomes of the acI lineage were successfully obtained from these initial cultures through whole genome amplification applied to more than hundreds of cultured acI cells. The genome sequences exhibited features of genome streamlining and showed that the strains are aerobic chemoheterotrophs sharing central metabolic pathways, with some differences among tribes that may underlie niche diversification within the acI lineage. Actinorhodopsin was found in all strains, but retinal biosynthesis was complete in only A1 and A4 tribes.
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Affiliation(s)
- Ilnam Kang
- Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea
| | - Suhyun Kim
- Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea
| | - Md Rashedul Islam
- Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea
| | - Jang-Cheon Cho
- Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea
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Newton ILG, Clark ME, Kent BN, Bordenstein SR, Qu J, Richards S, Kelkar YD, Werren JH. Comparative Genomics of Two Closely Related Wolbachia with Different Reproductive Effects on Hosts. Genome Biol Evol 2016; 8:1526-42. [PMID: 27189996 PMCID: PMC4898810 DOI: 10.1093/gbe/evw096] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Wolbachia pipientis are obligate intracellular bacteria commonly found in many arthropods. They can induce various reproductive alterations in hosts, including cytoplasmic incompatibility, male-killing, feminization, and parthenogenetic development, and can provide host protection against some viruses and other pathogens. Wolbachia differ from many other primary endosymbionts in arthropods because they undergo frequent horizontal transmission between hosts and are well known for an abundance of mobile elements and relatively high recombination rates. Here, we compare the genomes of two closely related Wolbachia (with 0.57% genome-wide synonymous divergence) that differ in their reproductive effects on hosts. wVitA induces a sperm-egg incompatibility (also known as cytoplasmic incompatibility) in the parasitoid insect Nasonia vitripennis, whereas wUni causes parthenogenetic development in a different parasitoid, Muscidifurax uniraptor Although these bacteria are closely related, the genomic comparison reveals rampant rearrangements, protein truncations (particularly in proteins predicted to be secreted), and elevated substitution rates. These changes occur predominantly in the wUni lineage, and may be due in part to adaptations by wUni to a new host environment, or its phenotypic shift to parthenogenesis induction. However, we conclude that the approximately 8-fold elevated synonymous substitution rate in wUni is due to a either an elevated mutation rate or a greater number of generations per year in wUni, which occurs in semitropical host species. We identify a set of genes whose loss or pseudogenization in the wUni lineage implicates them in the phenotypic shift from cytoplasmic incompatibility to parthenogenesis induction. Finally, comparison of these closely related strains allows us to determine the fine-scale mutation patterns in Wolbachia Although Wolbachia are AT rich, mutation probabilities estimated from 4-fold degenerate sites are not AT biased, and predict an equilibrium AT content much less biased than observed (57-50% AT predicted vs. 76% current content at degenerate sites genome wide). The contrast suggests selection for increased AT content within Wolbachia genomes.
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Affiliation(s)
| | | | - Bethany N Kent
- Department of Biological Sciences, Vanderbilt University
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University Department of Pathology, Microbiology and Immunology, Vanderbilt University
| | - Jiaxin Qu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Stephen Richards
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yogeshwar D Kelkar
- Department of Biostatistics and Computational Biology, University of Rochester
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Monodisperse Picoliter Droplets for Low-Bias and Contamination-Free Reactions in Single-Cell Whole Genome Amplification. PLoS One 2015; 10:e0138733. [PMID: 26389587 PMCID: PMC4577099 DOI: 10.1371/journal.pone.0138733] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/02/2015] [Indexed: 12/30/2022] Open
Abstract
Whole genome amplification (WGA) is essential for obtaining genome sequences from single bacterial cells because the quantity of template DNA contained in a single cell is very low. Multiple displacement amplification (MDA), using Phi29 DNA polymerase and random primers, is the most widely used method for single-cell WGA. However, single-cell MDA usually results in uneven genome coverage because of amplification bias, background amplification of contaminating DNA, and formation of chimeras by linking of non-contiguous chromosomal regions. Here, we present a novel MDA method, termed droplet MDA, that minimizes amplification bias and amplification of contaminants by using picoliter-sized droplets for compartmentalized WGA reactions. Extracted DNA fragments from a lysed cell in MDA mixture are divided into 105 droplets (67 pL) within minutes via flow through simple microfluidic channels. Compartmentalized genome fragments can be individually amplified in these droplets without the risk of encounter with reagent-borne or environmental contaminants. Following quality assessment of WGA products from single Escherichia coli cells, we showed that droplet MDA minimized unexpected amplification and improved the percentage of genome recovery from 59% to 89%. Our results demonstrate that microfluidic-generated droplets show potential as an efficient tool for effective amplification of low-input DNA for single-cell genomics and greatly reduce the cost and labor investment required for determination of nearly complete genome sequences of uncultured bacteria from environmental samples.
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Quantitative assessment of single-cell whole genome amplification methods for detecting copy number variation using hippocampal neurons. Sci Rep 2015; 5:11415. [PMID: 26091148 PMCID: PMC4650676 DOI: 10.1038/srep11415] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 05/08/2015] [Indexed: 02/04/2023] Open
Abstract
Single-cell genomic analysis has grown rapidly in recent years and finds widespread applications in various fields of biology, including cancer biology, development, immunology, pre-implantation genetic diagnosis, and neurobiology. To date, the amplification bias, amplification uniformity and reproducibility of the three major single cell whole genome amplification methods (GenomePlex WGA4, MDA and MALBAC) have not been systematically investigated using mammalian cells. In this study, we amplified genomic DNA from individual hippocampal neurons using three single-cell DNA amplification methods, and sequenced them at shallow depth. We then systematically evaluated the GC-bias, reproducibility, and copy number variations among individual neurons. Our results showed that single-cell genome sequencing results obtained from the MALBAC and WGA4 methods are highly reproducible and have a high success rate. The MALBAC displays significant biases towards high GC content. We then attempted to correct the GC bias issue by developing a bioinformatics pipeline, which allows us to call CNVs in single cell sequencing data, and chromosome level and sub-chromosomal level CNVs among individual neurons can be detected. We also proposed a metric to determine the CNV detection limits. Overall, MALBAC and WGA4 have better performance than MDA in detecting CNVs.
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15
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Kleiner M, Hooper LV, Duerkop BA. Evaluation of methods to purify virus-like particles for metagenomic sequencing of intestinal viromes. BMC Genomics 2015; 16:7. [PMID: 25608871 PMCID: PMC4308010 DOI: 10.1186/s12864-014-1207-4] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 12/24/2014] [Indexed: 01/21/2023] Open
Abstract
Background Viruses are a significant component of the intestinal microbiota in mammals. In recent years, advances in sequencing technologies and data analysis techniques have enabled detailed metagenomic studies investigating intestinal viromes (collections of bacteriophage and eukaryotic viral nucleic acids) and their potential contributions to the ecology of the microbiota. An important component of virome studies is the isolation and purification of virus-like particles (VLPs) from intestinal contents or feces. Several methods have been applied to isolate VLPs from intestinal samples, yet to our knowledge, the efficiency and reproducibility between methods have not been explored. A rigorous evaluation of methods for VLP purification is critical as many studies begin to move from descriptive analyses of virus diversity to studies striving to quantitatively compare viral abundances across many samples. Therefore, reproducible VLP purification methods which allow for high sample throughput are needed. Here we compared and evaluated four methods for VLP purification using artificial intestinal microbiota samples of known bacterial and viral composition. Results We compared the following four methods of VLP purification from fecal samples: (i) filtration + DNase, (ii) dithiothreitol treatment + filtration + DNase, (iii) filtration + DNase + PEG precipitation and (iv) filtration + DNase + CsCl density gradient centrifugation. Three of the four tested methods worked well for VLP purification. We observed several differences between methods related to the removal efficiency of bacterial and host DNAs and biases against specific phages. In particular the CsCl density gradient centrifugation method, which is frequently used for VLP purification, was most efficient in removing host derived DNA, but also showed strong discrimination against specific phages and showed a lower reproducibility of quantitative results. Conclusions Based on our data we recommend the use of methods (i) or (ii) for large scale studies when quantitative comparison of viral abundances across samples is required. The CsCl density gradient centrifugation method, while being excellently suited to achieve highly purified samples, in our opinion, should be used with caution when performing quantitative studies. Electronic supplementary material The online version of this article (doi:10.1186/s12864-014-1207-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Manuel Kleiner
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA. .,Current address: Department of Geoscience, University of Calgary, Calgary, AB, T2N 1 N4, Canada.
| | - Lora V Hooper
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA. .,The Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Breck A Duerkop
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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Single cell genome analysis of an uncultured heterotrophic stramenopile. Sci Rep 2014; 4:4780. [PMID: 24759094 PMCID: PMC3998028 DOI: 10.1038/srep04780] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 04/07/2014] [Indexed: 12/05/2022] Open
Abstract
A broad swath of eukaryotic microbial biodiversity cannot be cultivated in the lab and is therefore inaccessible to conventional genome-wide comparative methods. One promising approach to study these lineages is single cell genomics (SCG), whereby an individual cell is captured from nature and genome data are produced from the amplified total DNA. Here we tested the efficacy of SCG to generate a draft genome assembly from a single sample, in this case a cell belonging to the broadly distributed MAST-4 uncultured marine stramenopiles. Using de novo gene prediction, we identified 6,996 protein-encoding genes in the MAST-4 genome. This genetic inventory was sufficient to place the cell within the ToL using multigene phylogenetics and provided preliminary insights into the complex evolutionary history of horizontal gene transfer (HGT) in the MAST-4 lineage.
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