Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
1.
Nature ; 551(7681): 457-463, 2017 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-29088705

RESUMO

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.


Assuntos
Biodiversidade , Planeta Terra , Microbiota/genética , Animais , Archaea/genética , Archaea/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , Ecologia/métodos , Dosagem de Genes , Mapeamento Geográfico , Humanos , Plantas/microbiologia , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genética
2.
Appl Environ Microbiol ; 88(15): e0029022, 2022 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-35867581

RESUMO

Sirsoe methanicola, commonly known as the methane ice worm, is the only macrofaunal species known to inhabit the Gulf of Mexico methane hydrates. Little is known about this elusive marine polychaete that can colonize rich carbon and energy reserves. Metagenomic analysis of gut contents and worm fragments predicted diverse metabolic capabilities with the ability to utilize a range of nitrogen, sulfur, and organic carbon compounds through microbial taxa affiliated with Campylobacterales, Desulfobacterales, Enterobacterales, SAR324, Alphaproteobacteria, and Mycoplasmatales. Entomoplasmatales and Chitinivibrionales were additionally identified from extracted full-length 16S rRNA sequences, and read analysis identified 196 bacterial families. Overall, the microbial community appeared dominated by uncultured Sulfurospirillum, a taxon previously considered free-living rather than host-associated. Metagenome-assembled genomes (MAGs) classified as uncultured Sulfurospirillum predicted thiosulfate disproportionation and the reduction of tetrathionate, sulfate, sulfide/polysulfide, and nitrate. Microbial amino acid and vitamin B12 biosynthesis genes were identified in multiple MAGs, suggesting nutritional value to the host. Reads assigned to aerobic or anaerobic methanotrophic taxa were rare. IMPORTANCE Methane hydrates represent vast reserves of natural gas with roles in global carbon cycling and climate change. This study provided the first analysis of metagenomes associated with Sirsoe methanicola, the only polychaete species known to colonize methane hydrates. Previously unrecognized participation of Sulfurospirillum in a gut microbiome is provided, and the role of sulfur compound redox reactions within this community is highlighted. The comparative biology of S. methanicola is of general interest given research into the adverse effects of sulfide production in human gut microbiomes. In addition, taxonomic assignments are provided for nearly 200 bacterial families, expanding our knowledge of microbiomes in the deep sea.


Assuntos
Metagenoma , Poliquetos , Animais , Bactérias , Carbono/metabolismo , Humanos , Metano/metabolismo , Filogenia , Poliquetos/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Sulfetos/metabolismo
3.
Appl Environ Microbiol ; 88(9): e0246421, 2022 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35438519

RESUMO

Cyanobacterial harmful algal blooms (cyanoHABs) degrade freshwater ecosystems globally. Microcystis aeruginosa often dominates cyanoHABs and produces microcystin (MC), a class of hepatotoxins that poses threats to human and animal health. Microcystin toxicity is influenced by distinct structural elements across a diversity of related molecules encoded by variant mcy operons. However, the composition and distribution of mcy operon variants in natural blooms remain poorly understood. Here, we characterized the variant composition of mcy genes in western Lake Erie Microcystis blooms from 2014 and 2018. Sampling was conducted across several spatial and temporal scales, including different bloom phases within 2014, extensive spatial coverage on the same day (2018), and frequent, autonomous sampling over a 2-week period (2018). Mapping of metagenomic and metatranscriptomic sequences to reference sequences revealed three Microcystis mcy genotypes: complete (all genes present [mcyA-J]), partial (truncated mcyA, complete mcyBC, and missing mcyD-J), and absent (no mcy genes). We also detected two different variants of mcyB that may influence the production of microcystin congeners. The relative abundance of these genotypes was correlated with pH and nitrate concentrations. Metatranscriptomic analysis revealed that partial operons were, at times, the most abundant genotype and expressed in situ, suggesting the potential biosynthesis of truncated products. Quantification of genetic divergence between genotypes suggests that the observed strains are the result of preexisting heterogeneity rather than de novo mutation during the sampling period. Overall, our results show that natural Microcystis populations contain several cooccurring mcy genotypes that dynamically shift in abundance spatiotemporally via strain succession and likely influence the observed diversity of the produced congeners. IMPORTANCE Cyanobacteria are responsible for producing microcystins (MCs), a class of potent and structurally diverse toxins, in freshwater systems around the world. While microcystins have been studied for over 50 years, the diversity of their chemical forms and how this variation is encoded at the genetic level remain poorly understood, especially within natural populations of cyanobacterial harmful algal blooms (cyanoHABs). Here, we leverage community DNA and RNA sequences to track shifts in mcy genes responsible for producing microcystin, uncovering the relative abundance, expression, and variation of these genes. We studied this phenomenon in western Lake Erie, which suffers annually from cyanoHAB events, with impacts on drinking water, recreation, tourism, and commercial fishing.


Assuntos
Cianobactérias , Microcystis , Cianobactérias/genética , Ecossistema , Genótipo , Lagos/microbiologia , Microcistinas/genética , Microcistinas/metabolismo , Microcystis/genética , Microcystis/metabolismo , Óperon
4.
Appl Environ Microbiol ; 85(13)2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31028022

RESUMO

Evidence suggests many marine bacteria are cosmopolitan, with widespread but sparse strains poised to seed abundant populations under conducive growth conditions. However, studies supporting this "microbial seed bank" hypothesis have analyzed taxonomic marker genes rather than whole genomes/metagenomes, leaving open the possibility that disparate ocean regions harbor endemic gene content. The Red Sea is isolated geographically from the rest of the ocean and has a combination of high irradiance, high temperature, and high salinity that is unique among the oceans; we therefore asked whether it harbors endemic gene content. We sequenced and assembled single-cell genomes of 21 SAR11 (subclades Ia, Ib, Id, and II) and 5 Prochlorococcus (ecotype HLII) samples from the Red Sea and combined them with globally sourced reference genomes to cluster genes into ortholog groups (OGs). Ordination of OG composition could distinguish clades, including phylogenetically cryptic Prochlorococcus ecotypes LLII and LLIII. Compared with reference genomes, 1% of Prochlorococcus and 17% of SAR11 OGs were unique to the Red Sea genomes (RS-OGs). Most (83%) RS-OGs had no annotated function, but 65% of RS-OGs were expressed in diel Red Sea metatranscriptomes, suggesting they are functional. Searching Tara Oceans metagenomes, RS-OGs were as likely to be found as non-RS-OGs; nevertheless, Red Sea and other warm samples could be distinguished from cooler samples using the relative abundances of OGs. The results suggest that the prevalence of OGs in these surface ocean bacteria is largely cosmopolitan, with differences in population metagenomes manifested by differences in relative abundance rather than complete presence/absence of OGs.IMPORTANCE Studies have shown that as we sequence seawater from a selected environment deeper and deeper, we approach finding every bacterial taxon known for the ocean as a whole. However, such studies have focused on taxonomic marker genes rather than on whole genomes, raising the possibility that the lack of endemism results from the method of investigation. We took a geographically isolated water body, the Red Sea, and sequenced single cells from it. We compared those single-cell genomes to available genomes from around the ocean and to ocean-spanning metagenomes. We showed that gene ortholog groups found in Red Sea genomes but not in other genomes are nevertheless common across global ocean metagenomes. These results suggest that Baas Becking's hypothesis "everything is everywhere, but the environment selects" also applies to gene ortholog groups. This widely dispersed functional diversity may give oceanic microbial communities the functional capacity to respond rapidly to changing conditions.


Assuntos
Alphaproteobacteria/genética , Genoma Bacteriano , Metagenoma , Prochlorococcus/genética , Água do Mar/microbiologia , Oceano Índico , Filogenia
5.
Appl Environ Microbiol ; 83(10)2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28341673

RESUMO

Coral reefs are dynamic ecosystems known for decades to be endangered due, in large part, to anthropogenic impacts from land-based sources of pollution (LBSP). In this study, we utilized an Illumina-based next-generation sequencing approach to characterize prokaryotic and fungal communities from samples collected off the southeast coast of Florida. Water samples from coastal inlet discharges, oceanic outfalls of municipal wastewater treatment plants, treated wastewater effluent before discharge, open ocean samples, and coral tissue samples (mucus and polyps) were characterized to determine the relationships between microbial communities in these matrices and those in reef water and coral tissues. Significant differences in microbial communities were noted among all sample types but varied between sampling areas. Contamination from outfalls was found to be the greatest potential source of LBSP influencing native microbial community structure among all reef samples, although pollution from inlets was also noted. Notably, reef water and coral tissue communities were found to be more greatly impacted by LBSP at southern reefs, which also experienced the most degradation during the course of the study. The results of this study provide new insights into how microbial communities from LBSP can impact coral reefs in southeast Florida and suggest that wastewater outfalls may have a greater influence on the microbial diversity and structure of these reef communities than do contaminants carried in runoff, although the influences of runoff and coastal inlet discharge on coral reefs are still substantial.IMPORTANCE Coral reefs are known to be endangered due to sewage discharge and to runoff of nutrients, pesticides, and other substances associated with anthropogenic activity. Here, we used next-generation sequencing to characterize the microbial communities of potential contaminant sources in order to determine how environmental discharges of microbiota and their genetic material may influence the microbiomes of coral reef communities and coastal receiving waters. Runoff delivered through inlet discharges impacted coral microbial communities, but impacts from oceanic outfalls carrying treated wastewater were greater. Geographic differences in the degree of impact suggest that coral microbiomes may be influenced by the microbiological quality of treated wastewater.


Assuntos
Antozoários/microbiologia , Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbiota , Água do Mar/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Biodiversidade , Recifes de Corais , Florida , Fungos/classificação , Fungos/genética , Águas Residuárias/química , Águas Residuárias/microbiologia
6.
Environ Sci Technol ; 51(14): 7775-7784, 2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28633521

RESUMO

Total Maximum Daily Load (TMDL) stipulations remained unmet at a southern California beach despite a suite of management actions carried out since 2001, prompting exploration of a Natural Sources Exclusion (NSE) provision within the TMDL. Quantitative Microbial Source Tracking (MST) was employed from 2012 to 2015 to inventory sources of natural and anthropogenic fecal indicator bacteria (FIB). Data suggested FIB exceedances could be traced to gulls based on gull marker prevalence and correlations with FIB concentrations in seawater, sand, and eelgrass. In contrast, human marker concentrations and a tracer dye test did not indicate prevalent human sources. Exponential decay of gull marker in sand amended with live Catellicoccus marimammalium suggested that measured marker reflected fecal inputs versus growth outside the host. Improved water quality was coincident with a 2013 bird exclusion structure, consistent with NSE. However, load allocation needed for TMDL reconsideration was hampered by variable ratios of FIB, MST markers, and pathogens measured in seawater and in gull, cat, and raccoon feces. Quantitative Microbial Risk Assessment is a suggested path forward because such models can incorporate distributions from a combination of FIB sources and communicate criteria in terms of human health risk.


Assuntos
Praias , Enterococcaceae , Monitoramento Ambiental , Fezes , Animais , Bactérias , California , Gatos , Humanos , Microbiologia da Água
7.
Environ Sci Technol ; 50(18): 9900-6, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27538026

RESUMO

Total maximum daily load (TMDL) implementation at a southern California beach involved ultraviolet treatment of watershed drainage that provided >97% reduction in fecal indicator bacteria (FIB) concentrations. However, this pollutant control measure did not provide sufficient improvement of beach water quality, prompting further assessment. Investigation included microbial source tracking (MST) for human, gull, and canine fecal sources, monitoring of enterococci and fecal coliform, and measurement of chemical and physical water quality parameters for samples collected from watershed, groundwater, and beach sites, including a beach scour pond and tidal creek. FIB variability remained poorly modeled in regression analysis. However, MST revealed correlations between FIB and gull source tracking markers, leading to recommendations to manage gulls as a pollutant source. Beach conditions were followed for three years after implementation of a best management practice (BMP) to abate gulls using a falconry program for the beach and an upland landfill. The gull abatement BMP was associated with improved beach water quality, and this appears to be the first report of falconry in the context of TMDL implementation. Overall, MST data enabled management action despite an inability to fully model FIB dynamics in the coupled watershed-beach system.


Assuntos
Praias , Charadriiformes/microbiologia , Animais , California , Cães , Enterococcus , Monitoramento Ambiental , Fezes/microbiologia , Humanos , Microbiologia da Água , Qualidade da Água
8.
Environ DNA ; 6(1): 1-12, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38784600

RESUMO

The economic and methodological efficiencies of environmental DNA (eDNA) based survey approaches provide an unprecedented opportunity to assess and monitor aquatic environments. However, instances of inadequate communication from the scientific community about confidence levels, knowledge gaps, reliability, and appropriate parameters of eDNA-based methods have hindered their uptake in environmental monitoring programs and, in some cases, has created misperceptions or doubts in the management community. To help remedy this situation, scientists convened a session at the Second National Marine eDNA Workshop to discuss strategies for improving communications with managers. These include articulating the readiness of different eDNA applications, highlighting the strengths and limitations of eDNA tools for various applications or use cases, communicating uncertainties associated with specified uses transparently, and avoiding the exaggeration of exploratory and preliminary findings. Several key messages regarding implementation, limitations, and relationship to existing methods were prioritized. To be inclusive of the diverse managers, practitioners, and researchers, we and the other workshop participants propose the development of communication workflow plans, using RACI (Responsible, Accountable, Consulted, Informed) charts to clarify the roles of all pertinent individuals and parties and to minimize the chance for miscommunications. We also propose developing decision support tools such as Structured Decision-Making (SDM) to help balance the benefits of eDNA sampling with the inherent uncertainty, and developing an eDNA readiness scale to articulate the technological readiness of eDNA approaches for specific applications. These strategies will increase clarity and consistency regarding our understanding of the utility of eDNA-based methods, improve transparency, foster a common vision for confidently applying eDNA approaches, and enhance their benefit to the monitoring and assessment community.

9.
Appl Environ Microbiol ; 78(6): 1733-45, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22247142

RESUMO

This report documents the presence of fecal indicators and bacterial pathogens in sand at 53 California marine beaches using both culture-dependent and -independent (PCR and quantitative PCR [QPCR]) methods. Fecal indicator bacteria were widespread in California beach sand, with Escherichia coli and enterococci detected at 68% and 94% of the beaches surveyed, respectively. Somatic coliphages and a Bacteroidales human-specific fecal marker were detected at 43% and 13% of the beaches, respectively. Dry sand samples from almost 30% of the beaches contained at least one of the following pathogens: Salmonella spp., Campylobacter spp., Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), which were detected at 15%, 13%, 14%, and 3% of tested beaches, respectively. Fecal indicators and pathogens were poorly correlated to one another and to land cover. Sands were dry at the time of collection, and those with relatively high moisture tended to have higher concentrations or a more frequent occurrence of both indicators and pathogens. Using culture-dependent assays, fecal indicators decayed faster than pathogens in microcosm experiments using unaltered beach sand seeded with sewage and assessed by culture-dependent assays. The following order of persistence was observed (listed from most to least persistent): Campylobacter > Salmonella > somatic coliphages > enterococci > E. coli > F(+) phages. In contrast, pathogens decayed faster than fecal indicators in culture-independent assays: enterococci > Bacteroidales human-specific marker > Salmonella > Campylobacter. Microcosm experiments demonstrated that both indicators and pathogens were mobilized by wetting with seawater. Decay rates measured by QPCR were lower than those measured with culture-dependent methods. Enterococcal persistence and possible growth were observed for wetted microcosms relative to unwetted controls.


Assuntos
Bactérias/isolamento & purificação , Bactérias/patogenicidade , Praias , Sedimentos Geológicos/microbiologia , Microbiologia do Solo , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Carga Bacteriana , Biodiversidade , California , Humanos , Viabilidade Microbiana , Dióxido de Silício
10.
Front Microbiol ; 13: 1026596, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36713215

RESUMO

The expanding interest in marine microbiome and eDNA sequence data has led to a demand for sample collection and preservation standard practices to enable comparative assessments of results across studies and facilitate meta-analyses. We support this effort by providing guidelines based on a review of published methods and field sampling experiences. The major components considered here are environmental and resource considerations, sample processing strategies, sample storage options, and eDNA extraction protocols. It is impossible to provide universal recommendations considering the wide range of eDNA applications; rather, we provide information to design fit-for-purpose protocols. To manage scope, the focus here is on sampling collection and preservation of prokaryotic and microeukaryotic eDNA. Even with a focused view, the practical utility of any approach depends on multiple factors, including habitat type, available resources, and experimental goals. We broadly recommend enacting rigorous decontamination protocols, pilot studies to guide the filtration volume needed to characterize the target(s) of interest and minimize PCR inhibitor collection, and prioritizing sample freezing over (only) the addition of preservation buffer. An annotated list of studies that test these parameters is included for more detailed investigation on specific steps. To illustrate an approach that demonstrates fit-for-purpose methodologies, we provide a protocol for eDNA sampling aboard an oceanographic vessel. These guidelines can aid the decision-making process for scientists interested in sampling and sequencing marine microbiomes and/or eDNA.

11.
Gigascience ; 112022 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-35902092

RESUMO

BACKGROUND: Amplicon sequencing (metabarcoding) is a common method to survey diversity of environmental communities whereby a single genetic locus is amplified and sequenced from the DNA of whole or partial organisms, organismal traces (e.g., skin, mucus, feces), or microbes in an environmental sample. Several software packages exist for analyzing amplicon data, among which QIIME 2 has emerged as a popular option because of its broad functionality, plugin architecture, provenance tracking, and interactive visualizations. However, each new analysis requires the user to keep track of input and output file names, parameters, and commands; this lack of automation and standardization is inefficient and creates barriers to meta-analysis and sharing of results. FINDINGS: We developed Tourmaline, a Python-based workflow that implements QIIME 2 and is built using the Snakemake workflow management system. Starting from a configuration file that defines parameters and input files-a reference database, a sample metadata file, and a manifest or archive of FASTQ sequences-it uses QIIME 2 to run either the DADA2 or Deblur denoising algorithm; assigns taxonomy to the resulting representative sequences; performs analyses of taxonomic, alpha, and beta diversity; and generates an HTML report summarizing and linking to the output files. Features include support for multiple cores, automatic determination of trimming parameters using quality scores, representative sequence filtering (taxonomy, length, abundance, prevalence, or ID), support for multiple taxonomic classification and sequence alignment methods, outlier detection, and automated initialization of a new analysis using previous settings. The workflow runs natively on Linux and macOS or via a Docker container. We ran Tourmaline on a 16S ribosomal RNA amplicon data set from Lake Erie surface water, showing its utility for parameter optimization and the ability to easily view interactive visualizations through the HTML report, QIIME 2 viewer, and R- and Python-based Jupyter notebooks. CONCLUSION: Automated workflows like Tourmaline enable rapid analysis of environmental amplicon data, decreasing the time from data generation to actionable results. Tourmaline is available for download at github.com/aomlomics/tourmaline.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Software , Sequenciamento de Nucleotídeos em Larga Escala/métodos , RNA Ribossômico 16S/genética , Silicatos , Fluxo de Trabalho
12.
Nat Commun ; 13(1): 2448, 2022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-35508497

RESUMO

The ecological and oceanographic processes that drive the response of pelagic ocean microbiomes to environmental changes remain poorly understood, particularly in coastal upwelling ecosystems. Here we show that seasonal and interannual variability in coastal upwelling predicts pelagic ocean microbiome diversity and community structure in the Southern California Current region. Ribosomal RNA gene sequencing, targeting prokaryotic and eukaryotic microbes, from samples collected seasonally during 2014-2020 indicate that nitracline depth is the most robust predictor of spatial microbial community structure and biodiversity in this region. Striking ecological changes occurred due to the transition from a warm anomaly during 2014-2016, characterized by intense stratification, to cooler conditions in 2017-2018, representative of more typical upwelling conditions, with photosynthetic eukaryotes, especially diatoms, changing most strongly. The regional slope of nitracline depth exerts strong control on the relative proportion of highly diverse offshore communities and low biodiversity, but highly productive nearshore communities.


Assuntos
Microbiota , Plâncton , Biodiversidade , Ecossistema , Microbiota/genética , Nutrientes , Plâncton/genética , Água do Mar
13.
Gigascience ; 122022 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-37632753

RESUMO

Omic BON is a thematic Biodiversity Observation Network under the Group on Earth Observations Biodiversity Observation Network (GEO BON), focused on coordinating the observation of biomolecules in organisms and the environment. Our founding partners include representatives from national, regional, and global observing systems; standards organizations; and data and sample management infrastructures. By coordinating observing strategies, methods, and data flows, Omic BON will facilitate the co-creation of a global omics meta-observatory to generate actionable knowledge. Here, we present key elements of Omic BON's founding charter and first activities.


Assuntos
Biodiversidade , Conhecimento
14.
J Water Health ; 9(4): 718-33, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22048431

RESUMO

The Gulf of Mexico Alliance (GOMA) was tasked by the five Gulf State Governors to identify major issues affecting the Gulf of Mexico (GoM) and to set priorities for ameliorating these problems. One priority identified by GOMA is the need to improve detection methods for water quality indicators, pathogens and microbial source tracking. The United States Environmental Protection Agency (USEPA) is tasked with revising water quality criteria by 2012; however, the locations traditionally studied by the USEPA are not representative of the GoM and this has raised concern about whether or not the new criteria will be appropriate. This paper outlines a number of concerns, including deadlines associated with the USEPA Consent Decree, which may prevent inclusion of research needed to produce a well-developed set of methods and criteria appropriate for all regulated waters. GOMA makes several recommendations including ensuring that criteria formulation use data that include GoM-specific conditions (e.g. lower bather density, nonpoint sources), that rapid-testing methods be feasible and adequately controlled, and that USEPA maintains investments in water quality research once the new criteria are promulgated in order to assure that outstanding scientific questions are addressed and that scientifically defensible criteria are achieved for the GoM and other regulated waterbodies.


Assuntos
Monitoramento Ambiental/legislação & jurisprudência , United States Environmental Protection Agency/legislação & jurisprudência , Microbiologia da Água/normas , Poluentes da Água/normas , Monitoramento Ambiental/normas , Golfo do México , Organizações , Estados Unidos
15.
Mol Ecol Resour ; 21(7): 2546-2564, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34235858

RESUMO

DNA metabarcoding is an important tool for molecular ecology. However, its effectiveness hinges on the quality of reference sequence databases and classification parameters employed. Here we evaluate the performance of MiFish 12S taxonomic assignments using a case study of California Current Large Marine Ecosystem fishes to determine best practices for metabarcoding. Specifically, we use a taxonomy cross-validation by identity framework to compare classification performance between a global database comprised of all available sequences and a curated database that only includes sequences of fishes from the California Current Large Marine Ecosystem. We demonstrate that the regional database provides higher assignment accuracy than the comprehensive global database. We also document a tradeoff between accuracy and misclassification across a range of taxonomic cutoff scores, highlighting the importance of parameter selection for taxonomic classification. Furthermore, we compared assignment accuracy with and without the inclusion of additionally generated reference sequences. To this end, we sequenced tissue from 597 species using the MiFish 12S primers, adding 252 species to GenBank's existing 550 California Current Large Marine Ecosystem fish sequences. We then compared species and reads identified from seawater environmental DNA samples using global databases with and without our generated references, and the regional database. The addition of new references allowed for the identification of 16 additional native taxa representing 17.0% of total reads from eDNA samples, including species with vast ecological and economic value. Together these results demonstrate the importance of comprehensive and curated reference databases for effective metabarcoding and the need for locus-specific validation efforts.


Assuntos
DNA Ambiental , Ecossistema , Animais , Biodiversidade , Código de Barras de DNA Taxonômico , Peixes/genética , Água do Mar
16.
Limnol Oceanogr Methods ; 8: 269-284, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-21165155

RESUMO

Harmful algal blooms (HABs) are a serious public health risk in coastal waters. As the intensity and frequency of HABs continue to rise, new methods of detection are needed for reliable identification. Herein, we developed a high-throughput, multiplex, bead array technique for the detection of the dinoflagellates Karenia brevis and Karenia mikimotoi. The method combined the Luminex detection system with two novel technologies: locked nucleic acid-modified oligonucleotides (LNA) and Mirus Label IT(®) nucleic acid technology. To study the feasibility of the method, we evaluated the performance of modified and unmodified LNA probes with amplicon targets that were biotin labeled with two different strategies: direct chemical labeling (Mirus Label IT) versus enzymatic end-labeling (single biotinylated primer). The results illustrated that LNA probes hybridized to complementary single-stranded DNA with better affinity and displayed higher fluorescence intensities than unmodified oligonucleotide DNA probes. The latter effect was more pronounced when the assay was carried out at temperatures above 53°C degree. As opposed to the enzymatic 5' terminal labeling technique, the chemical-labeling method enhanced the level of fluorescence by as much as ~83%. The detection limits of the assay, which were established with LNA probes and Mirus Label IT system, ranged from 0.05 to 46 copies of rRNA. This high-throughput method, which represents the first molecular detection strategy to integrate Luminex technology with LNA probes and Mirus Label IT, can be adapted for the detection of other HABs and is well suited for the monitoring of red tides at pre-blooming and blooming conditions.

18.
Mar Pollut Bull ; 54(6): 757-70, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17328925

RESUMO

Standard methods to identify microbial contaminants in the environment are slow, laborious, and can require specialized expertise. This study investigated electrochemical detection of microbial contaminants using commercially available, hand-held instruments. Electrochemical assays were developed for a red tide dinoflagellate (Karenia brevis), fecal-indicating bacteria (Enterococcus spp.), markers indicative of human sources of fecal pollution (human cluster Bacteroides and the esp gene of Enterococcus faecium), bacterial pathogens (Escherichia coli 0157:H7, Salmonella spp., Campylobacter jejuni, Staphylococcus aureus), and a viral pathogen (adenovirus). For K. brevis, two assay formats (Rapid PCR-Detect and Hybrid PCR-Detect) were tested and both provided detection limits of 10 genome equivalents for DNA isolated from K. brevis culture and amplified by PCR. Sensitivity with coastal water samples was sufficient to detect K. brevis that was "present" (

Assuntos
Dinoflagellida/isolamento & purificação , Monitoramento Ambiental/métodos , Eucariotos/isolamento & purificação , Água do Mar/análise , Microbiologia da Água , Poluentes da Água/análise , Animais , Dinoflagellida/genética , Eletroquímica , Monitoramento Ambiental/instrumentação , Eucariotos/genética , Reprodutibilidade dos Testes , Água do Mar/microbiologia
19.
Mar Pollut Bull ; 54(5): 521-36, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17350051

RESUMO

Research to understand and remediate coastal pollution is moving toward a multitiered approach in which traditional enumeration of fecal indicators is accompanied by molecular analysis of a variety of targets. Technology that rapidly detects multiple microbial contaminants would benefit from such an approach. The Luminex 100 system is a suspension array that assays multiple analytes rapidly in a single well of a microtiter plate. The ability of the system to simultaneously detect multiple fecal indicating bacteria in environmental samples was tested. Primer/probe sets were designed to simultaneously detect the following fecal indicators: the Bacteroides fragilis group, Enterococcus spp., Escherichia coli and Shigella spp., Bacteroides distasonis, and Ent. faecalis. Specificity and sensitivity of the Luminex probes was tested against laboratory cultures. In addition, sequencing, culture plate testing, and specificity testing with environmental isolates were steps taken to validate the function of the assay with environmental samples. Luminex response to cultures and to environmental samples was consistent with sequencing results, suggesting that the technology has the potential to simultaneously detect multiple targets for coastal water quality applications, particularly as progress is made to efficiently extract DNA from water and sediment matrices.


Assuntos
Bactérias/genética , Monitoramento Ambiental/métodos , Fezes/microbiologia , Corantes Fluorescentes , Rios/microbiologia , Água do Mar/microbiologia , Dióxido de Silício/análise , Sequência de Bases , Análise por Conglomerados , Primers do DNA , Sondas de DNA , Microesferas , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA