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Degradation of biological macromolecules supports uncultured microbial populations in Guaymas Basin hydrothermal sediments. THE ISME JOURNAL 2021; 15:3480-3497. [PMID: 34112968 PMCID: PMC8630151 DOI: 10.1038/s41396-021-01026-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/05/2023]
Abstract
Hydrothermal sediments contain large numbers of uncultured heterotrophic microbial lineages. Here, we amended Guaymas Basin sediments with proteins, polysaccharides, nucleic acids or lipids under different redox conditions and cultivated heterotrophic thermophiles with the genomic potential for macromolecule degradation. We reconstructed 20 metagenome-assembled genomes (MAGs) of uncultured lineages affiliating with known archaeal and bacterial phyla, including endospore-forming Bacilli and candidate phylum Marinisomatota. One Marinisomatota MAG had 35 different glycoside hydrolases often in multiple copies, seven extracellular CAZymes, six polysaccharide lyases, and multiple sugar transporters. This population has the potential to degrade a broad spectrum of polysaccharides including chitin, cellulose, pectin, alginate, chondroitin, and carrageenan. We also describe thermophiles affiliating with the genera Thermosyntropha, Thermovirga, and Kosmotoga with the capability to make a living on nucleic acids, lipids, or multiple macromolecule classes, respectively. Several populations seemed to lack extracellular enzyme machinery and thus likely scavenged oligo- or monomers (e.g., MAGs affiliating with Archaeoglobus) or metabolic products like hydrogen (e.g., MAGs affiliating with Thermodesulfobacterium or Desulforudaceae). The growth of methanogens or the production of methane was not observed in any condition, indicating that the tested macromolecules are not degraded into substrates for methanogenesis in hydrothermal sediments. We provide new insights into the niches, and genomes of microorganisms that actively degrade abundant necromass macromolecules under oxic, sulfate-reducing, and fermentative thermophilic conditions. These findings improve our understanding of the carbon flow across trophic levels and indicate how primary produced biomass sustains complex and productive ecosystems.
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Niegowska M, Sanseverino I, Navarro A, Lettieri T. Knowledge gaps in the assessment of antimicrobial resistance in surface waters. FEMS Microbiol Ecol 2021; 97:fiab140. [PMID: 34625810 PMCID: PMC8528692 DOI: 10.1093/femsec/fiab140] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/06/2021] [Indexed: 11/26/2022] Open
Abstract
The spread of antibiotic resistance in the water environment has been widely described. However, still many knowledge gaps exist regarding the selection pressure from antibiotics, heavy metals and other substances present in surface waters as a result of anthropogenic activities, as well as the extent and impact of this phenomenon on aquatic organisms and humans. In particular, the relationship between environmental concentrations of antibiotics and the acquisition of ARGs by antibiotic-sensitive bacteria as well as the impact of heavy metals and other selective agents on antimicrobial resistance (AMR) need to be defined. Currently, established safety values are based on the effects of antibiotic toxicity neglecting the question of AMR spread. In turn, risk assessment of antibiotics in waterbodies remains a complex question implicating multiple variables and unknowns reinforced by the lack of harmonized protocols and official guidelines. In the present review, we discussed current state-of-the-art and the knowledge gaps related to pressure exerted by antibiotics and heavy metals on aquatic environments and their relationship to the spread of AMR. Along with this latter, we reflected on (i) the risk assessment in surface waters, (ii) selective pressures contributing to its transfer and propagation and (iii) the advantages of metagenomics in investigating AMR. Furthermore, the role of microplastics in co-selection for metal and antibiotic resistance, together with the need for more studies in freshwater are highlighted.
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Affiliation(s)
- Magdalena Niegowska
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, 21027 Ispra, Italy
| | - Isabella Sanseverino
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, 21027 Ispra, Italy
| | - Anna Navarro
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, 21027 Ispra, Italy
| | - Teresa Lettieri
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, 21027 Ispra, Italy
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Bendia AG, Lemos LN, Mendes LW, Signori CN, Bohannan BJM, Pellizari VH. Metabolic potential and survival strategies of microbial communities across extreme temperature gradients on Deception Island volcano, Antarctica. Environ Microbiol 2021; 23:4054-4073. [PMID: 34245102 DOI: 10.1111/1462-2920.15649] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 11/27/2022]
Abstract
Active volcanoes in Antarctica have remarkable temperature and geochemical gradients that could select for a wide variety of microbial adaptive mechanisms and metabolic pathways. Deception Island is a stratovolcano flooded by the sea, resulting in contrasting ecosystems such as permanent glaciers and active fumaroles, which creates steep gradients that have been shown to affect microbial diversity. In this study, we used shotgun metagenomics and metagenome-assembled genomes to explore the metabolic potentials and survival strategies of microbial communities along an extreme temperature gradient in fumarole and glacier sediments on Deception Island. We observed that communities from a 98 °C fumarole were significantly enriched in genes related to hyperthermophilic (e.g. reverse gyrase, GroEL/GroES and thermosome) and oxidative stress responses, as well as genes related to sulfate reduction, ammonification and carbon fixation. Communities from <80 °C fumaroles possessed more genes related osmotic, cold- and heat-shock responses, and diverse metabolic potentials, such as those related to sulfur oxidation and denitrification, while glacier communities showed abundant metabolic potentials mainly related to heterotrophy. Through the reconstruction of genomes, we were able to reveal the metabolic potentials and different survival strategies of underrepresented taxonomic groups, especially those related to Nanoarchaeota, Pyrodictiaceae and thermophilic ammonia-oxidizing archaeal lineages.
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Affiliation(s)
- Amanda Gonçalves Bendia
- Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo (USP), Praça do Oceanográfico, 191, São Paulo, SP, CEP 05508-120, Brazil
| | - Leandro Nascimento Lemos
- Laboratório de Biologia Celular e Molecular, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenário 303, Piracicaba, SP, CEP 13416-00, Brazil
| | - Lucas William Mendes
- Laboratório de Biologia Celular e Molecular, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenário 303, Piracicaba, SP, CEP 13416-00, Brazil
| | - Camila Negrão Signori
- Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo (USP), Praça do Oceanográfico, 191, São Paulo, SP, CEP 05508-120, Brazil
| | - Brendan J M Bohannan
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
| | - Vivian Helena Pellizari
- Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo (USP), Praça do Oceanográfico, 191, São Paulo, SP, CEP 05508-120, Brazil
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Tang X, Yu L, Yi Y, Wang J, Wang S, Meng C, Liu S, Hao Y, Zhang Y, Cao X, Jian H, Xiao X. Phylogenomic analysis reveals a two-stage process of the evolutionary transition of Shewanella from the upper ocean to the hadal zone. Environ Microbiol 2020; 23:744-756. [PMID: 32657519 DOI: 10.1111/1462-2920.15162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/21/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022]
Abstract
Shewanella strains are characterized by versatile metabolic capabilities, resulting in their wide distribution in the ocean at different depths. Considering that particle sedimentation is an important dynamic process in the ocean, we hypothesized that hadal Shewanella species evolved from the upper ocean. In this study, we isolated three novel Shewanella strains from deep-sea sediments in the Southwest Indian Ocean. Genome sequencing indicated that strains YLB-06 and YLB-08 represent two novel species in the genus Shewanella. Through phylogenomic analysis, we showed that speciation and genomic changes in marine Shewanella strains are related to water depth. We further confirmed the aforementioned hypothesis and revealed a two-stage process of the evolutionary transition of Shewanella from the upper ocean to the hadal zone by comparative genomics and gene gain/loss analysis. Finally, the transcriptomic analysis demonstrated that recently obtained genes are strictly repressed and may thus play a minor role in the response to environmental changes.
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Affiliation(s)
- Xixiang Tang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Libo Yu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Yi Yi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiahua Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Siyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Canxing Meng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shunzhang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yali Hao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaorong Cao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Huahua Jian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
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Sun QL, Zhang J, Wang MX, Cao L, Du ZF, Sun YY, Liu SQ, Li CL, Sun L. High-Throughput Sequencing Reveals a Potentially Novel Sulfurovum Species Dominating the Microbial Communities of the Seawater-Sediment Interface of a Deep-Sea Cold Seep in South China Sea. Microorganisms 2020; 8:microorganisms8050687. [PMID: 32397229 PMCID: PMC7284658 DOI: 10.3390/microorganisms8050687] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022] Open
Abstract
In the Formosa cold seep of the South China Sea (SCS), large amounts of methane and sulfide hydrogen are released from the subseafloor. In this study, we systematically investigated the microbial communities in the seawater–sediment interface of Formosa cold seep using high-throughput sequencing techniques including amplicon sequencing based on next-generation sequencing and Pacbio amplicon sequencing platforms, and metagenomics. We found that Sulfurovum dominated the microbial communities in the sediment–seawater interface, including the seawater close to the seepage, the surface sediments, and the gills of the dominant animal inhabitant (Shinkaia crosnieri). A nearly complete 16S rRNA gene sequence of the dominant operational taxonomic units (OTUs) was obtained from the Pacbio sequencing platforms and classified as OTU-L1, which belonged to Sulfurovum. This OTU was potentially novel as it shared relatively low similarity percentages (<97%) of the gene sequence with its close phylogenetic species. Further, a draft genome of Sulfurovum was assembled using the binning technique based on metagenomic data. Genome analysis suggested that Sulfurovum sp. in this region may fix carbon by the reductive tricarboxylic acid (rTCA) pathway, obtain energy by oxidizing reduced sulfur through sulfur oxidizing (Sox) pathway, and utilize nitrate as electron acceptors. These results demonstrated that Sulfurovum probably plays an important role in the carbon, sulfur, and nitrogen cycles of the Formosa cold seep of the SCS. This study improves our understanding of the diversity, distribution, and function of sulfur-oxidizing bacteria in deep-sea cold seep.
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Affiliation(s)
- Qing-Lei Sun
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Q.-L.S.); (J.Z.); (Y.-Y.S.)
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Jian Zhang
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Q.-L.S.); (J.Z.); (Y.-Y.S.)
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (M.-X.W.); (L.C.); (Z.-F.D.)
| | - Min-Xiao Wang
- Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (M.-X.W.); (L.C.); (Z.-F.D.)
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lei Cao
- Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (M.-X.W.); (L.C.); (Z.-F.D.)
| | - Zeng-Feng Du
- Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (M.-X.W.); (L.C.); (Z.-F.D.)
- Key Lab of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yuan-Yuan Sun
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Q.-L.S.); (J.Z.); (Y.-Y.S.)
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Shi-Qi Liu
- Faculty of Science, University of Amsterdam, 1098XH Amsterdam, The Netherlands;
| | - Chao-Lun Li
- Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (M.-X.W.); (L.C.); (Z.-F.D.)
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (C.-L.L.); (L.S.); Tel.: +86-532-8289-8599 (C.-L.L.); +86-532-8289-8829 (L.S.)
| | - Li Sun
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Q.-L.S.); (J.Z.); (Y.-Y.S.)
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Correspondence: (C.-L.L.); (L.S.); Tel.: +86-532-8289-8599 (C.-L.L.); +86-532-8289-8829 (L.S.)
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Watanabe-Yanai A, Iwata T, Kusumoto M, Tamamura Y, Akiba M. Transcriptomic analysis of Campylobacter jejuni grown in a medium containing serine as the main energy source. Arch Microbiol 2018; 201:571-579. [PMID: 30448871 DOI: 10.1007/s00203-018-1596-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/09/2018] [Accepted: 11/13/2018] [Indexed: 11/29/2022]
Abstract
Campylobacter jejuni is one of the most important causes of food-borne diseases in industrialized countries. Amino acids are an important nutrient source for this pathogen because it lacks enzymes related to glycolysis. However, the metabolic characteristics of C. jejuni grown in a nutrient-restricted medium with specific amino acids have not been fully elucidated. This study shows that C. jejuni NCTC 11168 grows well in a nutrient-restricted medium containing serine, aspartate, glutamate, and proline. Subtracting serine significantly reduced growth, but the removal of the three other amino acids did not, suggesting that serine is a priority among the four amino acids. A transcriptomic analysis of C. jejuni NCTC 11168 grown in a medium with serine as the main energy source was then performed. Serine seemed to be sensed by some chemoreceptors, and C. jejuni reached an adaptation stage with active growth in which the expression of flagellar assembly components was downregulated and the biosyntheses of multiple amino acids and nucleotide sugars were upregulated. These data suggest that C. jejuni NCTC 11168 requires serine as a nutrient.
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Affiliation(s)
- Ayako Watanabe-Yanai
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Taketoshi Iwata
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masahiro Kusumoto
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Yukino Tamamura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masato Akiba
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan. .,Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka, Japan.
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Al-Ayoubi SR, Schinkel PKF, Berghaus M, Herzog M, Winter R. Combined effects of osmotic and hydrostatic pressure on multilamellar lipid membranes in the presence of PEG and trehalose. SOFT MATTER 2018; 14:8792-8802. [PMID: 30339170 DOI: 10.1039/c8sm01343h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We studied the interaction of lipid membranes with the disaccharide trehalose (TRH), which is known to stabilize biomembranes against various environmental stress factors. Generally, stress factors include low/high temperature, shear, osmotic and hydrostatic pressure. Small-angle X-ray-scattering was applied in combination with fluorescence spectroscopy and calorimetric measurements to get insights into the influence of trehalose on the supramolecular structure, hydration level, and elastic and thermodynamic properties as well as phase behavior of the model biomembrane DMPC, covering a large region of the temperature, osmotic and hydrostatic pressure phase space. We observed distinct effects of trehalose on the topology of the lipid's supramolecular structure. Trehalose, unlike osmotic pressure induced by polyethylene glycol, leads to a decrease of lamellar order and a swelling of multilamellar vesicles, which is attributable to direct interactions between the membrane and trehalose. Our results revealed a distinct biphasic concentration dependence of the observed effects of trehalose. While trehalose intercalates between the polar head groups at low concentrations, the effects after saturation are dominated by the exclusion of trehalose from the membrane surface.
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Affiliation(s)
- Samy R Al-Ayoubi
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
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Pereira MB, Wallroth M, Jonsson V, Kristiansson E. Comparison of normalization methods for the analysis of metagenomic gene abundance data. BMC Genomics 2018; 19:274. [PMID: 29678163 PMCID: PMC5910605 DOI: 10.1186/s12864-018-4637-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/28/2018] [Indexed: 01/17/2023] Open
Abstract
Background In shotgun metagenomics, microbial communities are studied through direct sequencing of DNA without any prior cultivation. By comparing gene abundances estimated from the generated sequencing reads, functional differences between the communities can be identified. However, gene abundance data is affected by high levels of systematic variability, which can greatly reduce the statistical power and introduce false positives. Normalization, which is the process where systematic variability is identified and removed, is therefore a vital part of the data analysis. A wide range of normalization methods for high-dimensional count data has been proposed but their performance on the analysis of shotgun metagenomic data has not been evaluated. Results Here, we present a systematic evaluation of nine normalization methods for gene abundance data. The methods were evaluated through resampling of three comprehensive datasets, creating a realistic setting that preserved the unique characteristics of metagenomic data. Performance was measured in terms of the methods ability to identify differentially abundant genes (DAGs), correctly calculate unbiased p-values and control the false discovery rate (FDR). Our results showed that the choice of normalization method has a large impact on the end results. When the DAGs were asymmetrically present between the experimental conditions, many normalization methods had a reduced true positive rate (TPR) and a high false positive rate (FPR). The methods trimmed mean of M-values (TMM) and relative log expression (RLE) had the overall highest performance and are therefore recommended for the analysis of gene abundance data. For larger sample sizes, CSS also showed satisfactory performance. Conclusions This study emphasizes the importance of selecting a suitable normalization methods in the analysis of data from shotgun metagenomics. Our results also demonstrate that improper methods may result in unacceptably high levels of false positives, which in turn may lead to incorrect or obfuscated biological interpretation. Electronic supplementary material The online version of this article (10.1186/s12864-018-4637-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mariana Buongermino Pereira
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, SE-412 96, Gothenburg, Sweden
| | - Mikael Wallroth
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, SE-412 96, Gothenburg, Sweden
| | - Viktor Jonsson
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, SE-412 96, Gothenburg, Sweden
| | - Erik Kristiansson
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, SE-412 96, Gothenburg, Sweden.
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