1
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Vogel AL, Thompson KJ, Straub D, Musat F, Gutierrez T, Kleindienst S. Genetic redundancy in the naphthalene-degradation pathway of Cycloclasticus pugetii strain PS-1 enables response to varying substrate concentrations. FEMS Microbiol Ecol 2024; 100:fiae060. [PMID: 38614960 DOI: 10.1093/femsec/fiae060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 03/22/2024] [Accepted: 04/12/2024] [Indexed: 04/15/2024] Open
Abstract
Polycyclic aromatic hydrocarbon (PAH) contamination in marine environments range from low-diffusive inputs to high loads. The influence of PAH concentration on the expression of functional genes [e.g. those encoding ring-hydroxylating dioxygenases (RHDs)] has been overlooked in PAH biodegradation studies. However, understanding marker-gene expression under different PAH loads can help to monitor and predict bioremediation efficiency. Here, we followed the expression (via RNA sequencing) of Cycloclasticus pugetii strain PS-1 in cell suspension experiments under different naphthalene (100 and 30 mg L-1) concentrations. We identified genes encoding previously uncharacterized RHD subunits, termed rhdPS1α and rhdPS1β, that were highly transcribed in response to naphthalene-degradation activity. Additionally, we identified six RHD subunit-encoding genes that responded to naphthalene exposure. By contrast, four RHD subunit genes were PAH-independently expressed and three other RHD subunit genes responded to naphthalene starvation. Cycloclasticus spp. could, therefore, use genetic redundancy in key PAH-degradation genes to react to varying PAH loads. This genetic redundancy may restrict the monitoring of environmental hydrocarbon-degradation activity using single-gene expression. For Cycloclasticus pugetii strain PS-1, however, the newly identified rhdPS1α and rhdPS1β genes might be potential target genes to monitor its environmental naphthalene-degradation activity.
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Affiliation(s)
- Anjela L Vogel
- Eberhard Karls University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, Tübingen 72076, Germany
- University of Stuttgart, Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), Am Bandtäle 2, Stuttgart 70569, Germany
| | - Katharine J Thompson
- Eberhard Karls University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, Tübingen 72076, Germany
- University of Stuttgart, Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), Am Bandtäle 2, Stuttgart 70569, Germany
| | - Daniel Straub
- Eberhard Karls University of Tübingen, Quantitative Biology Center (QBiC), Auf der Morgenstelle 10, Tübingen 72076, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Florin Musat
- Aarhus University, Department of Biology, Section for Microbiology, Ny Munkegade 116, Aarhus C 8000, Denmark
- Babeş-Bolyai University, Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Str. Republicii nr 44, Cluj-Napoca 400015, Romania
| | - Tony Gutierrez
- Heriot-Watt University, Institute of Mechanical Process and Energy Engineering (IMPEE), School of Engineering and Physical Sciences, Edinburgh EH14 4AS, UK
| | - Sara Kleindienst
- Eberhard Karls University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, Tübingen 72076, Germany
- University of Stuttgart, Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), Am Bandtäle 2, Stuttgart 70569, Germany
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2
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Simpson W, Brigmon RL, Howard D, Jackson M, Kugler A, Brown V. Utilization of lasso peptides for biodegradation of polycyclic aromatic hydrocarbons. Environ Microbiol Rep 2024; 16:e13197. [PMID: 38600035 PMCID: PMC11006600 DOI: 10.1111/1758-2229.13197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 06/20/2023] [Indexed: 04/12/2024]
Abstract
Many microbial genes involved in degrading recalcitrant environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs) have been identified and characterized. However, all molecular mechanisms required for PAH utilization have not yet been elucidated. In this work, we demonstrate the proposed involvement of lasso peptides in the utilization of the PAH phenanthrene in Sphingomonas BPH. Transpositional mutagenesis of Sphingomonas BPH with the miniTn5 transposon yielded 3 phenanthrene utilization deficient mutants, #257, #1778, and #1782. In mutant #1782, Tn5 had inserted into the large subunit of the naph/bph dioxygenase gene. In mutant #1778, Tn5 had inserted into the B2 protease gene of a lasso peptide cluster. This finding is the first report on the role of lasso peptides in PAH utilization. Our studies also demonstrate that interruption of the lasso peptide cluster resulted in a significant increase in the amount of biosurfactant produced in the presence of glucose when compared to the wild-type strain. Collectively, these results suggest that the mechanisms Sphingomonas BPH utilizes to degrade phenanthrene are far more complex than previously understood and that the #1778 mutant may be a good candidate for bioremediation when glucose is applied as an amendment due to its higher biosurfactant production.
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Affiliation(s)
- Waltena Simpson
- Department of Biological and Physical SciencesSouth Carolina State UniversityOrangeburgSouth CarolinaUSA
| | | | - Daniel Howard
- Department of Biological and Physical SciencesSouth Carolina State UniversityOrangeburgSouth CarolinaUSA
| | - Makaela Jackson
- Department of Biological and Physical SciencesSouth Carolina State UniversityOrangeburgSouth CarolinaUSA
| | - Alex Kugler
- Savannah River National LaboratoryAikenSouth CarolinaUSA
| | - Victoria Brown
- Department of Biological and Physical SciencesSouth Carolina State UniversityOrangeburgSouth CarolinaUSA
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3
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Walton JL, Buchan A. Evidence for novel polycyclic aromatic hydrocarbon degradation pathways in culturable marine isolates. Microbiol Spectr 2024; 12:e0340923. [PMID: 38084970 PMCID: PMC10783047 DOI: 10.1128/spectrum.03409-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/10/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE Polycyclic aromatic hydrocarbon (PAH) pollution is widespread throughout marine environments and significantly affects native flora and fauna. Investigating microbes responsible for degrading PAHs in these environments provides a greater understanding of natural attenuation in these systems. In addition, the use of culture-based approaches to inform bioinformatic and omics-based approaches is useful in identifying novel mechanisms of PAH degradation that elude genetic biomarker-based investigations. Furthermore, culture-based approaches allow for the study of PAH co-metabolism, which increasingly appears to be a prominent mechanism for PAH degradation in marine microbes.
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Affiliation(s)
- Jillian L. Walton
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Alison Buchan
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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4
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Vázquez Rosas Landa M, De Anda V, Rohwer RR, Angelova A, Waldram G, Gutierrez T, Baker BJ. Exploring novel alkane-degradation pathways in uncultured bacteria from the North Atlantic Ocean. mSystems 2023; 8:e0061923. [PMID: 37702502 PMCID: PMC10654063 DOI: 10.1128/msystems.00619-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 07/19/2023] [Indexed: 09/14/2023] Open
Abstract
IMPORTANCE Petroleum pollution in the ocean has increased because of rapid population growth and modernization, requiring urgent remediation. Our understanding of the metabolic response of native microbial communities to oil spills is not well understood. Here, we explored the baseline hydrocarbon-degrading communities of a subarctic Atlantic region to uncover the metabolic potential of the bacteria that inhabit the surface and subsurface water. We conducted enrichments with a 13C-labeled hydrocarbon to capture the fraction of the community actively using the hydrocarbon. We then combined this approach with metagenomics to identify the metabolic potential of this hydrocarbon-degrading community. This revealed previously undescribed uncultured bacteria with unique metabolic mechanisms involved in aerobic hydrocarbon degradation, indicating that temperature may be pivotal in structuring hydrocarbon-degrading baseline communities. Our findings highlight gaps in our understanding of the metabolic complexity of hydrocarbon degradation by native marine microbial communities.
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Affiliation(s)
- Mirna Vázquez Rosas Landa
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
- Instituto de Ciencias del Mar y Limnologia Universidad Nacional Autónoma de Mexico, Unidad Académica de Ecologia y Biodiversidad Acuática, Mexico City, Mexico
| | - Valerie De Anda
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Robin R. Rohwer
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Angelina Angelova
- School of Engineering and Physical Sciences, Institute of Mechanical, Process and Energy Engineering (IMPEE), Heriot-Watt University, Edinburgh, United Kingdom
| | - Georgia Waldram
- School of Engineering and Physical Sciences, Institute of Mechanical, Process and Energy Engineering (IMPEE), Heriot-Watt University, Edinburgh, United Kingdom
| | - Tony Gutierrez
- School of Engineering and Physical Sciences, Institute of Mechanical, Process and Energy Engineering (IMPEE), Heriot-Watt University, Edinburgh, United Kingdom
| | - Brett J. Baker
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
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5
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Wang W, Xia J, Wang Z, Shao Z. Bacterial cell sensing and signaling pathway for external polycyclic aromatic hydrocarbons (PAHs). iScience 2023; 26:107912. [PMID: 37841585 PMCID: PMC10570129 DOI: 10.1016/j.isci.2023.107912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/19/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023] Open
Abstract
The mechanism by which a bacterial cell senses external nutrients remains largely unknown. In this study, we identified a bacterial cell sensing system for polycyclic aromatic hydrocarbons (PAHs) in a common marine PAH-using bacterium, Cycloclasticus. It consists of an outer membrane receptor (PahS) and a periplasmic protein (PahP) in combination with a two-component sensing system (TCS) that ensures a rapid response to PAH occurrence by directly controlling serial reactions including chemotactic sensing and movement, PAH uptake and intracellular PAH metabolism. PahS protrudes from the cell and acts as a PAH sensor, transducing the PAH signal across the outer membrane to its periplasmic partner PahP, which in turn transduces the PAH signal across the periplasm to a specialized TCS. This sensing system plays a critical role in sensing and promoting the metabolism of PAHs, which can be scavenged by various hydrocarbon-degrading bacteria.
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Affiliation(s)
- Wanpeng Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
- Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen, China
| | - Jingyu Xia
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Zining Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Zongze Shao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
- Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen, China
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6
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Kim J, Hwangbo M, Shih CH, Chu KH. Advances and perspectives of using stable isotope probing (SIP)-based technologies in contaminant biodegradation. Water Res X 2023; 20:100187. [PMID: 37671037 PMCID: PMC10477051 DOI: 10.1016/j.wroa.2023.100187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/18/2023] [Accepted: 06/06/2023] [Indexed: 09/07/2023]
Abstract
Stable isotope probing (SIP) is a powerful tool to study microbial community structure and function in both nature and engineered environments. Coupling with advanced genomics and other techniques, SIP studies have generated substantial information to allow researchers to draw a clearer picture of what is occurring in complex microbial ecosystems. This review provides an overview of the advances of SIP-based technologies over time, summarizes the status of SIP applications to contaminant biodegradation, provides critical perspectives on ecological interactions within the community, and important factors (controllable and non-controllable) to be considered in SIP experimental designs and data interpretation. Current trend and perspectives of adapting SIP techniques for environmental applications are also discussed.
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Affiliation(s)
- Jinha Kim
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Myung Hwangbo
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
- School of Earth, Environmental and Marine Sciences, The University of Texas – Rio Grande Valley, Brownsville, TX, USA
| | - Chih-Hsuan Shih
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
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7
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Vyshenska D, Sampara P, Singh K, Tomatsu A, Kauffman WB, Nuccio EE, Blazewicz SJ, Pett-Ridge J, Louie KB, Varghese N, Kellom M, Clum A, Riley R, Roux S, Eloe-Fadrosh EA, Ziels RM, Malmstrom RR. A standardized quantitative analysis strategy for stable isotope probing metagenomics. mSystems 2023; 8:e0128022. [PMID: 37377419 PMCID: PMC10469821 DOI: 10.1128/msystems.01280-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 04/19/2023] [Indexed: 06/29/2023] Open
Abstract
Stable isotope probing (SIP) facilitates culture-independent identification of active microbial populations within complex ecosystems through isotopic enrichment of nucleic acids. Many DNA-SIP studies rely on 16S rRNA gene sequences to identify active taxa, but connecting these sequences to specific bacterial genomes is often challenging. Here, we describe a standardized laboratory and analysis framework to quantify isotopic enrichment on a per-genome basis using shotgun metagenomics instead of 16S rRNA gene sequencing. To develop this framework, we explored various sample processing and analysis approaches using a designed microbiome where the identity of labeled genomes and their level of isotopic enrichment were experimentally controlled. With this ground truth dataset, we empirically assessed the accuracy of different analytical models for identifying active taxa and examined how sequencing depth impacts the detection of isotopically labeled genomes. We also demonstrate that using synthetic DNA internal standards to measure absolute genome abundances in SIP density fractions improves estimates of isotopic enrichment. In addition, our study illustrates the utility of internal standards to reveal anomalies in sample handling that could negatively impact SIP metagenomic analyses if left undetected. Finally, we present SIPmg, an R package to facilitate the estimation of absolute abundances and perform statistical analyses for identifying labeled genomes within SIP metagenomic data. This experimentally validated analysis framework strengthens the foundation of DNA-SIP metagenomics as a tool for accurately measuring the in situ activity of environmental microbial populations and assessing their genomic potential. IMPORTANCE Answering the questions, "who is eating what?" and "who is active?" within complex microbial communities is paramount for our ability to model, predict, and modulate microbiomes for improved human and planetary health. These questions can be pursued using stable isotope probing to track the incorporation of labeled compounds into cellular DNA during microbial growth. However, with traditional stable isotope methods, it is challenging to establish links between an active microorganism's taxonomic identity and genome composition while providing quantitative estimates of the microorganism's isotope incorporation rate. Here, we report an experimental and analytical workflow that lays the foundation for improved detection of metabolically active microorganisms and better quantitative estimates of genome-resolved isotope incorporation, which can be used to further refine ecosystem-scale models for carbon and nutrient fluxes within microbiomes.
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Affiliation(s)
- Dariia Vyshenska
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Pranav Sampara
- Department of Civil Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kanwar Singh
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Andy Tomatsu
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - W. Berkeley Kauffman
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
- Life & Environmental Sciences Department, University of California Merced, Merced, California, USA
| | - Katherine B. Louie
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Neha Varghese
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Matthew Kellom
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Alicia Clum
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Robert Riley
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Simon Roux
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Emiley A. Eloe-Fadrosh
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Ryan M. Ziels
- Department of Civil Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Rex R. Malmstrom
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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8
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Vogel AL, Thompson KJ, Straub D, App CB, Gutierrez T, Löffler FE, Kleindienst S. Substrate-independent expression of key functional genes in Cycloclasticus pugetii strain PS-1 limits their use as markers for PAH biodegradation. Front Microbiol 2023; 14:1185619. [PMID: 37455737 PMCID: PMC10338962 DOI: 10.3389/fmicb.2023.1185619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/22/2023] [Indexed: 07/18/2023] Open
Abstract
Microbial degradation of petroleum hydrocarbons is a crucial process for the clean-up of oil-contaminated environments. Cycloclasticus spp. are well-known polycyclic aromatic hydrocarbon (PAH) degraders that possess PAH-degradation marker genes including rhd3α, rhd2α, and pahE. However, it remains unknown if the expression of these genes can serve as an indicator for active PAH degradation. Here, we determined transcript-to-gene (TtG) ratios with (reverse transcription) qPCR in cultures of Cycloclasticus pugetii strain PS-1 grown with naphthalene, phenanthrene, a mixture of these PAHs, or alternate substrates (i.e., no PAHs). Mean TtG ratios of 1.99 × 10-2, 1.80 × 10-3, and 3.20 × 10-3 for rhd3α, rhd2α, and pahE, respectively, were measured in the presence or absence of PAHs. The TtG values suggested that marker-gene expression is independent of PAH degradation. Measurement of TtG ratios in Arctic seawater microcosms amended with water-accommodated crude oil fractions, and incubated under in situ temperature conditions (i.e., 1.5°C), only detected Cycloclasticus spp. rhd2α genes and transcripts (mean TtG ratio of 4.15 × 10-1). The other marker genes-rhd3α and pahE-were not detected, suggesting that not all Cycloclasticus spp. carry these genes and a broader yet-to-be-identified repertoire of PAH-degradation genes exists. The results indicate that the expression of PAH marker genes may not correlate with PAH-degradation activity, and transcription data should be interpreted cautiously.
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Affiliation(s)
- Anjela L. Vogel
- Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
- Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), University of Stuttgart, Stuttgart, Germany
| | - Katharine J. Thompson
- Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
- Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), University of Stuttgart, Stuttgart, Germany
| | - Daniel Straub
- Quantitative Biology Center (QBiC), Eberhard Karls University of Tübingen, Tübingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Constantin B. App
- Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Tony Gutierrez
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, United Kingdom
| | - Frank E. Löffler
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN, United States
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN, United States
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - Sara Kleindienst
- Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
- Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), University of Stuttgart, Stuttgart, Germany
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9
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Li H, Wang X, Peng S, Lai Z, Mai Y. Seasonal variation of temperature affects HMW-PAH accumulation in fishery species by bacterially mediated LMW-PAH degradation. Sci Total Environ 2022; 853:158617. [PMID: 36084776 DOI: 10.1016/j.scitotenv.2022.158617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/03/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
Currently, the specific mechanism generating seasonal variation in polycyclic aromatic hydrocarbons (PAHs) via bacterial biodegradation remains unclear, and whether this alteration affects PAH bioaccumulation is unknown. Therefore, we performed a study between 2015 and 2020 to investigate the effects of seasonal variation on bacterial communities and PAH bioaccumulation in the Pearl River Estuary. Significantly high PAH concentrations in both aquatic and fishery species were determined in dry seasons (the mean ∑16PAH concentration: water, 37.24 ng/L (2015), 30.83 ng/L (2020); fish, 51.01 ng/L (2015) and 72.60 ng/L (2020)) compared to wet seasons (the mean ∑16PAH concentration: water, 22.38 ng/L (2015), 19.40 ng/L(2020); fish, 25.28 ng/L (2015) and 32.59 ng/L (2020)). Distinct differences in taxonomic and functional composition of bacterial communities related to biodegradation of low molecular weight PAHs (LMW-PAHs) were observed between seasons, and the concentrations of PAHs were negatively correlated with seasonal variation in temperature. Temperature-related specific bacterial taxa (e.g., Stenotrophomonas) directly or indirectly participated in LMW-PAH degradation via encoding PAH degradation enzymes (e.g., protocatechuate 4,5-dioxygenase) that subsequently led to bioaccumulation of high molecular weight PAHs (HMW-PAHs) in wild and fishery species due to LMW-PAHs in the water. Based on this alteration, the ecological risk posed by PAHs decreased in wet seasons, and an unbalanced spatio-temporal distribution of PAHs was observed in this estuary. These results suggest that seasonal variation of temperature affects HMW-PAH accumulation in fishery species via bacterially mediated LMW-PAH biodegradation.
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Affiliation(s)
- Haiyan Li
- Key Laboratory of Prevention and Control for Aquatic Invasive Alien Species, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Aquatic Animal Immunology and Sustainable Aquaculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Xuesong Wang
- Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology, Guangdong Provincial Engineering Research Center for Ambient Mass Spectrometry, Institute of Analysis, Guangdong Academy of Sciences (China National Analytical Center, Guangzhou), Guangzhou 510070, China.
| | - Songyao Peng
- Pearl River Water Resources Research Institute, Guangzhou 510611, China
| | - Zini Lai
- Key Laboratory of Prevention and Control for Aquatic Invasive Alien Species, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Aquatic Animal Immunology and Sustainable Aquaculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Yongzhan Mai
- Key Laboratory of Prevention and Control for Aquatic Invasive Alien Species, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Aquatic Animal Immunology and Sustainable Aquaculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
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10
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Greenlon A, Sieradzki E, Zablocki O, Koch BJ, Foley MM, Kimbrel JA, Hungate BA, Blazewicz SJ, Nuccio EE, Sun CL, Chew A, Mancilla CJ, Sullivan MB, Firestone M, Pett-Ridge J, Banfield JF. Quantitative Stable-Isotope Probing (qSIP) with Metagenomics Links Microbial Physiology and Activity to Soil Moisture in Mediterranean-Climate Grassland Ecosystems. mSystems 2022; 7:e0041722. [PMID: 36300946 DOI: 10.1128/msystems.00417-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The growth and physiology of soil microorganisms, which play vital roles in biogeochemical cycling, are shaped by both current and historical soil environmental conditions. Here, we developed and applied a genome-resolved metagenomic implementation of quantitative stable isotope probing (qSIP) with an H218O labeling experiment to identify actively growing soil microorganisms and their genomic capacities. qSIP enabled measurement of taxon-specific growth because isotopic incorporation into microbial DNA requires production of new genome copies. We studied three Mediterranean grassland soils across a rainfall gradient to evaluate the hypothesis that historic precipitation levels are an important factor controlling trait selection. We used qSIP-informed genome-resolved metagenomics to resolve the active subset of soil community members and identify their characteristic ecophysiological traits. Higher year-round precipitation levels correlated with higher activity and growth rates of flagellar motile microorganisms. In addition to heavily isotopically labeled bacteria, we identified abundant isotope-labeled phages, suggesting phage-induced cell lysis likely contributed to necromass production at all three sites. Further, there was a positive correlation between phage activity and the activity of putative phage hosts. Contrary to our expectations, the capacity to decompose the diverse complex carbohydrates common in soil organic matter or oxidize methanol and carbon monoxide were broadly distributed across active and inactive bacteria in all three soils, implying that these traits are not highly selected for by historical precipitation. IMPORTANCE Soil moisture is a critical factor that strongly shapes the lifestyle of soil organisms by changing access to nutrients, controlling oxygen diffusion, and regulating the potential for mobility. We identified active microorganisms in three grassland soils with similar mineral contexts, yet different historic rainfall inputs, by adding water labeled with a stable isotope and tracking that isotope in DNA of growing microbes. By examining the genomes of active and inactive microorganisms, we identified functions that are enriched in growing organisms, and showed that different functions were selected for in different soils. Wetter soil had higher activity of motile organisms, but activity of pathways for degradation of soil organic carbon compounds, including simple carbon substrates, were comparable for all three soils. We identified many labeled, and thus active bacteriophages (viruses that infect bacteria), implying that the cells they killed contributed to soil organic matter. The activity of these bacteriophages was significantly correlated with activity of their hosts.
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McLean AR, Torres-Morales J, Dewhirst FE, Borisy GG, Welch JLM. Site-tropism of streptococci in the oral microbiome. Mol Oral Microbiol 2022; 37:229-243. [PMID: 36073311 PMCID: PMC9691528 DOI: 10.1111/omi.12387] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/08/2022] [Accepted: 08/28/2022] [Indexed: 11/29/2022]
Abstract
A detailed understanding of where bacteria localize is necessary to advance microbial ecology and microbiome-based therapeutics. The site-specialist hypothesis predicts that most microbes in the human oral cavity have a primary habitat type within the mouth where they are most abundant. We asked whether this hypothesis accurately describes the distribution of the members of the genus Streptococcus, a clinically relevant taxon that dominates most oral sites. Prior analysis of 16S rRNA gene sequencing data indicated that some oral Streptococcus clades are site-specialists while others may be generalists. However, within complex microbial populations composed of numerous closely related species and strains, such as the oral streptococci, genome-scale analysis is necessary to provide the resolution to discriminate closely related taxa with distinct functional roles. Here, we assess whether individual species within this genus are specialists using publicly available genomic sequence data that provide species-level resolution. We chose a set of high-quality representative genomes for human oral Streptococcus species. Onto these genomes, we mapped shotgun metagenomic sequencing reads from supragingival plaque, tongue dorsum, and other sites in the oral cavity. We found that every abundant Streptococcus species in the healthy human oral cavity showed strong site-tropism and that even closely related species such as S. mitis, S. oralis, and S. infantis specialized in different sites. These findings indicate that closely related bacteria can have distinct habitat distributions in the absence of dispersal limitation and under similar environmental conditions and immune regimes. Substantial overlap between the core genes of these three species suggests that site-specialization is determined by subtle differences in genomic content.
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Affiliation(s)
- Anthony R. McLean
- The Forsyth Institute, Cambridge, MA 02142
- Marine Biological Laboratory, Woods Hole, MA 02543
| | | | - Floyd E. Dewhirst
- The Forsyth Institute, Cambridge, MA 02142
- Harvard School of Dental Medicine, Boston, MA 02115
| | | | - Jessica L. Mark Welch
- The Forsyth Institute, Cambridge, MA 02142
- Marine Biological Laboratory, Woods Hole, MA 02543
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Nuccio EE, Blazewicz SJ, Lafler M, Campbell AN, Kakouridis A, Kimbrel JA, Wollard J, Vyshenska D, Riley R, Tomatsu A, Hestrin R, Malmstrom RR, Firestone M, Pett-Ridge J. HT-SIP: a semi-automated stable isotope probing pipeline identifies cross-kingdom interactions in the hyphosphere of arbuscular mycorrhizal fungi. Microbiome 2022; 10:199. [PMID: 36434737 PMCID: PMC9700909 DOI: 10.1186/s40168-022-01391-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Linking the identity of wild microbes with their ecophysiological traits and environmental functions is a key ambition for microbial ecologists. Of many techniques that strive for this goal, Stable-isotope probing-SIP-remains among the most comprehensive for studying whole microbial communities in situ. In DNA-SIP, actively growing microorganisms that take up an isotopically heavy substrate build heavier DNA, which can be partitioned by density into multiple fractions and sequenced. However, SIP is relatively low throughput and requires significant hands-on labor. We designed and tested a semi-automated, high-throughput SIP (HT-SIP) pipeline to support well-replicated, temporally resolved amplicon and metagenomics experiments. We applied this pipeline to a soil microhabitat with significant ecological importance-the hyphosphere zone surrounding arbuscular mycorrhizal fungal (AMF) hyphae. AMF form symbiotic relationships with most plant species and play key roles in terrestrial nutrient and carbon cycling. RESULTS Our HT-SIP pipeline for fractionation, cleanup, and nucleic acid quantification of density gradients requires one-sixth of the hands-on labor compared to manual SIP and allows 16 samples to be processed simultaneously. Automated density fractionation increased the reproducibility of SIP gradients compared to manual fractionation, and we show adding a non-ionic detergent to the gradient buffer improved SIP DNA recovery. We applied HT-SIP to 13C-AMF hyphosphere DNA from a 13CO2 plant labeling study and created metagenome-assembled genomes (MAGs) using high-resolution SIP metagenomics (14 metagenomes per gradient). SIP confirmed the AMF Rhizophagus intraradices and associated MAGs were highly enriched (10-33 atom% 13C), even though the soils' overall enrichment was low (1.8 atom% 13C). We assembled 212 13C-hyphosphere MAGs; the hyphosphere taxa that assimilated the most AMF-derived 13C were from the phyla Myxococcota, Fibrobacterota, Verrucomicrobiota, and the ammonia-oxidizing archaeon genus Nitrososphaera. CONCLUSIONS Our semi-automated HT-SIP approach decreases operator time and improves reproducibility by targeting the most labor-intensive steps of SIP-fraction collection and cleanup. We illustrate this approach in a unique and understudied soil microhabitat-generating MAGs of actively growing microbes living in the AMF hyphosphere (without plant roots). The MAGs' phylogenetic composition and gene content suggest predation, decomposition, and ammonia oxidation may be key processes in hyphosphere nutrient cycling. Video Abstract.
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Affiliation(s)
- Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Marissa Lafler
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Ashley N. Campbell
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Anne Kakouridis
- Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jeffrey A. Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Jessica Wollard
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | | | | | | | - Rachel Hestrin
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA USA
| | | | - Mary Firestone
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Life & Environmental Sciences Department, University of California Merced, Merced, CA USA
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13
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Abstract
Viral metagenomics has expanded our knowledge of the ecology of uncultured viruses, within both environmental (e.g., terrestrial and aquatic) and host-associated (e.g., plants and animals, including humans) contexts. Here, we emphasize the implementation of an ecological framework in viral metagenomic studies to address questions in virology rarely considered ecological, which can change our perception of viruses and how they interact with their surroundings. An ecological framework explicitly considers diverse variants of viruses in populations that make up communities of interacting viruses, with ecosystem-level effects. It provides a structure for the study of the diversity, distributions, dynamics, and interactions of viruses with one another, hosts, and the ecosystem, including interactions with abiotic factors. An ecological framework in viral metagenomics stands poised to broadly expand our knowledge in basic and applied virology. We highlight specific fundamental research needs to capitalize on its potential and advance the field. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Pacifica Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, Colorado 80309, USA.,These authors contributed equally to this article
| | - Anushila Chatterjee
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, Colorado 80309, USA.,These authors contributed equally to this article
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA; .,Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Gareth Trubl
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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