The bacterial hitchhiker's guide to COI: Universal primer-based COI capture probes fail to exclude bacterial DNA, but 16S capture leaves metazoa behind

Environmental DNA (eDNA) metabarcoding from water samples has, in recent years, shown great promise for biodiversity monitoring. However, universal primers targeting the cytochrome oxidase I (COI) marker gene popular in metazoan studies have displayed high levels of nontarget amplification. To date, enrichment methods bypassing amplification have not been able to match the detection levels of conventional metabarcoding. This study evaluated the use of universal metabarcoding primers as capture probes to either isolate target DNA, or to remove nontarget DNA, prior to amplification by using biotinylated versions of universal metazoan and bacterial barcoding primers, namely metazoan COI and bacterial 16S. Additionally, each step of the protocol was assessed by amplifying both COI and bacterial 16S to investigate the effect on the metazoan and bacterial communities. Bacterial abundance increased in response to the captures (COI library), while the quality of the captured DNA was improved. The metazoan-based probe captured bacterial DNA in a range that was also amplifiable with the 16S primers, demonstrating the ability of universal capture probes to isolate larger fragments of DNA from eDNA. This concept could be applied to metazoan metabarcoding, by using a truly conserved site without a high-level taxonomic resolution as a target of capture, to isolate DNA spanning over a nearby barcoding region, which can then be processed through conventional metabarcoding by amplification protocol.

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eDNA metabarcoding outperforms traditional fisheries sampling and reveals fine-scale heterogeneity in a temperate freshwater lake

10.1101/2020.10.20.347203 ◽

2020 ◽

Author(s):

Rebecca R Gehri ◽

Wesley A. Larson ◽

Kristen Gruenthal ◽

Nicholas Sard ◽

Yue Shi

Keyword(s):

Community Composition ◽

Lake Water ◽

Water Samples ◽

High Throughput Sequencing ◽

Environmental Dna ◽

Aquatic Systems ◽

Taxonomic Resolution ◽

Universal Primers ◽

Great Promise ◽

Fish Diversity

AbstractUnderstanding biodiversity in aquatic systems is critical to ecological research and conservation efforts, but accurately measuring species richness using traditional methods can be challenging. Environmental DNA (eDNA) metabarcoding, which uses high-throughput sequencing and universal primers to amplify DNA from multiple species present in an environmental sample, has shown great promise for augmenting results from traditional sampling to characterize fish communities in aquatic systems. Few studies, however, have compared exhaustive traditional sampling with eDNA metabarcoding of corresponding water samples at a small spatial scale. We intensively sampled Boardman Lake (137 ha) in Michigan, USA from May to June in 2019 using gill and fyke nets and paired each net set with lake water samples collected in triplicate. We analyzed water samples using eDNA metabarcoding with 12S and 16S fish-specific primers and compared estimates of fish diversity among methods. In total, we set 60 nets and analyzed 180 1 L lake water samples. We captured a total of 12 fish species in our traditional gear and detected 40 taxa in the eDNA water samples, which included all the species observed in nets. The 12S and 16S assays detected a comparable number of taxa, but taxonomic resolution varied between the two genes. In our traditional gear, there was a clear difference in the species selectivity between the two net types, and there were several species commonly detected in the eDNA samples that were not captured in nets. Finally, we detected spatial heterogeneity in fish community composition across relatively small scales in Boardman Lake with eDNA metabarcoding, but not with traditional sampling. Our results demonstrated that eDNA metabarcoding was substantially more efficient than traditional gear for estimating community composition, highlighting the utility of eDNA metabarcoding for assessing species diversity and informing management and conservation.

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Improved freshwater macroinvertebrate detection from environmental DNA through minimized nontarget amplification

ARPHA Conference Abstracts ◽

10.3897/aca.4.e64753 ◽

2021 ◽

Vol 4 ◽

Author(s):

Mandy Sander ◽

Arne Beermann ◽

Dominik Buchner ◽

Vasco Elbrecht ◽

Peter Haase ◽

...

Keyword(s):

Benthic Invertebrates ◽

Environmental Dna ◽

Benthic Invertebrate ◽

Coi Gene ◽

Taxonomic Resolution ◽

Universal Primers ◽

Reference Database ◽

Mountain Range ◽

Degenerate Primers ◽

Universal Primer

Environmental DNA (eDNA) metabarcoding is a new, promising, and non-invasive method to detect biodiversity in aquatic environments. So far, it has mainly been used to screen for fish and amphibian diversity and rarely to detect macroinvertebrates. Typically, DNA metabarcoding relies on PCR amplification of a fragment of the mitochondrial cytochrome c oxidase I (COI) gene with degenerate primers. In comparison to other genes like 16S, COI has a greater taxonomic resolution and availability of an extensive reference database. Benthic stream invertebrates are of critical importance for regulatory biomonitoring, but when using universal primers on eDNA isolated from water, the number of reads and OTUs is “watered down”. This means the target taxa, macroinvertebrates, are underrepresented in comparison to other nontarget taxa, e. g. algae, bacteria, and fungi. The aim of the project was to design an insect-specific primer, which minimizes nontarget amplification. Therefore, data from a time series of 15 months at the Kinzig (Hesse), a silica-rich low-mountain-range stream, which is part of the Rhine‑Main‑Observatory (LTER site) was generated using the universal primers BF2/BR2. With this data we identified the most abundant nontarget taxa and designed a new reverse primer (EPTDr2n) with 3’ ‐ specificity toward benthic invertebrate taxa. Primer specificity was validated in silico together with universal forward primer fwhF2 using available data from GenBank and BOLD. 20 eDNA samples from the Kinzig River and its tributaries were then used to test the new primer in situ together with primer fwhF2. The new primer combination showed a much higher amplification of benthic invertebrates, insects in particular, than two other universal primer pairs for both, number of target reads (fwhF2/EPTDr2n: 99.6% versus BF2/BR2: 25.89% and fwhF2/fwhR2n: 39.04%; Fig. 1) and number of target species (fwhF2/EPTDr2n: 305 versus BF2/BR2: 113 and fwhF2/fwhR2n: 185). Additionally, the number of benthic invertebrate species exceeded even the number of 153 species identified by expert taxonomists at nearby sites across two decades of sampling. While several taxa reported, like a few trichopteran genera, flatworms, and some crustaceans, were not found, the primer shows greatly improved results for eDNA metabarcoding of benthic invertebrates(Leese et al. 2021).

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Novel Universal Primers for Metabarcoding eDNA Surveys of Marine Mammals and Other Marine Vertebrates

10.1101/759746 ◽

2019 ◽

Author(s):

Elena Valsecchi ◽

Jonas Bylemans ◽

Simon J. Goodman ◽

Roberto Lombardi ◽

Ian Carr ◽

...

Keyword(s):

Marine Mammals ◽

High Throughput Sequencing ◽

Environmental Dna ◽

16S Rrna Genes ◽

Rrna Genes ◽

Taxonomic Resolution ◽

Universal Primers ◽

Marine Biodiversity ◽

Primer Sets ◽

Marine Megafauna

ABSTRACTMetabarcoding studies using environmental DNA (eDNA) and high throughput sequencing (HTS) are rapidly becoming an important tool for assessing and monitoring marine biodiversity, detecting invasive species, and supporting basic ecological research. Several barcode loci targeting teleost fish and elasmobranchs have previously been developed, but to date primer sets focusing on other marine megafauna, such as marine mammals have received less attention. Similarly, there have been few attempts to identify potentially ‘universal’ barcode loci which may be informative across multiple marine vertebrate Orders. Here we describe the design and validation of four new sets of primers targeting hypervariable regions of the vertebrate mitochondrial 12S and 16S rRNA genes, which have conserved priming sites across virtually all cetaceans, pinnipeds, elasmobranchs, boney fish, sea turtles and birds, and amplify fragments with consistently high levels of taxonomically diagnostic sequence variation. ‘In silico’ validation using the OBITOOLS software showed our new barcode loci outperformed most existing vertebrate barcode loci for taxon detection and resolution. We also evaluated sequence diversity and taxonomic resolution of the new barcode loci in 680 complete marine mammal mitochondrial genomes demonstrating that they are effective at resolving amplicons for most taxa to the species level. Finally, we evaluated the performance of the primer sets with eDNA samples from aquarium communities with known species composition. These new primers will potentially allow surveys of complete marine vertebrate communities in single HTS metabarcoding assessments, simplifying workflows, reducing costs, and increasing accessibility to a wider range of investigators.

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Improved freshwater macroinvertebrate detection from eDNA through minimized non-target amplification

10.1101/2020.04.27.063545 ◽

2020 ◽

Cited By ~ 3

Author(s):

Florian Leese ◽

Mandy Sander ◽

Dominik Buchner ◽

Vasco Elbrecht ◽

Peter Haase ◽

...

Keyword(s):

Stream Water ◽

Pcr Amplification ◽

Environmental Dna ◽

Coi Gene ◽

Taxonomic Resolution ◽

Universal Primers ◽

Reference Database ◽

Degenerate Primers ◽

Long Term Ecological Research

AbstractDNA metabarcoding of freshwater communities typically relies on PCR amplification of a fragment of the mitochondrial cytochrome c oxidase (COI) gene with degenerate primers. The advantage of COI is its taxonomic resolution and the availability of an extensive reference database. However, when universal primers are used on environmental DNA (eDNA) isolated from stream water, macroinvertebrate read and OTU numbers are typically “watered down”, i.e. diluted, compared to whole specimen ‘bulk samples’ due to greater co-amplification of abundant non-target taxa such as algae and bacteria. Because stream macroinvertebrate taxa are of prime importance for regulatory biomonitoring, more effective ways to capture their diversity via eDNA isolated from water are important. In this study, we aimed to improve macroinvertebrate assessment from eDNA by minimizing non-target amplification. Therefore, we generated data using universal primers BF2/BR2 throughout 15 months from a German Long-Term Ecological Research (LTER) site, the River Kinzig, to identify most abundant non-target taxa. Based on these data, we designed a new reverse primer (EPTDr2n) with 3’-specificity towards macrozoobenthic taxa and validated its specificity in silico together with universal forward primer fwhF2 using available data from GenBank and BOLD. We then performed in vitro tests using 20 eDNA samples taken in the Kinzig catchment. We found that the percentage of target reads was much higher for the new primer combination compared to two universal macrozoobenthic primer pairs, BF2/BR2 and fwhF2/fwhR2n (>99 % vs. 21.4 % and 41.25 %, respectively). Likewise, number of detected macroinvertebrate taxa was substantially higher (351 vs. 46 and 170, respectively) and exceeded the number of 257 taxa identified by expert taxonomists at nearby sites across two decades of sampling. While few taxa such as Turbellaria were not detected, we show that the optimized primer avoids the dilution problem and thus significantly improves macroinvertebrate detection for bioassessment and -monitoring.

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Development and evaluation of PCR primers for environmental DNA (eDNA) metabarcoding of Amphibia

10.1101/2021.10.29.466374 ◽

2021 ◽

Author(s):

Masayuki K. Sakata ◽

Mone U. Kawata ◽

Atsushi Kurabayashi ◽

Takaki Kurita ◽

Masatoshi Nakamura ◽

...

Keyword(s):

Pcr Amplification ◽

Environmental Dna ◽

Pcr Primers ◽

Taxonomic Resolution ◽

Rrna Gene ◽

Biodiversity Monitoring ◽

Natural Ecosystems ◽

Universal Primer ◽

Primer Sets

Biodiversity monitoring is important for the conservation of natural ecosystems in general, but particularly for amphibians, whose populations are pronouncedly declining. However, amphibians ecological traits (e.g., nocturnal or aquatic) often prevent their precise monitoring. Environmental DNA (eDNA) metabarcoding-analysis of extra-organismal DNA released into the environment-allows the easy and effective monitoring of the biodiversity of aquatic organisms. Here, we developed and tested the utility of original PCR primer sets. First, we conducted in vitro PCR amplification tests with universal primer candidates using total DNA extracted from amphibian tissues. Five primer sets successfully amplified the target DNA fragments (partial 16S rRNA gene fragments of 160-311 bp) from all 16 taxa tested (from the three living amphibian orders Anura, Caudata, and Gymnophiona). Next, we investigated the taxonomic resolution retrieved using each primer set. The results revealed that the universal primer set Amph16S had the highest resolution among the tested sets. Finally, we applied Amph16S to actual metabarcoding and evaluated its detection capability by comparing the species detected using eDNA and physical survey (capture-based sampling and visual survey) in multiple agricultural ecosystems across Japan (160 sites in 10 areas). The eDNA metabarcoding with Amph16S detected twice as many species as the physical surveys (16 vs. 8 species, respectively), indicating the effectiveness of Amph16S in biodiversity monitoring and ecological research for amphibian communities.

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Cytosine and adenine deaminase base-editors induce broad and nonspecific changes in gene expression and splicing

Communications Biology ◽

10.1038/s42003-021-02406-5 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Jiao Fan ◽

Yige Ding ◽

Chao Ren ◽

Ziguo Song ◽

Jie Yuan ◽

...

Keyword(s):

Gene Expression ◽

Double Strand Breaks ◽

Great Promise ◽

Single Nucleotide ◽

Strand Breaks ◽

Dna Base ◽

Target Dna ◽

Single Nucleotide Variations ◽

Adenine Deaminase ◽

Target Rna

AbstractCytosine or adenine base editors (CBEs or ABEs) hold great promise in therapeutic applications because they enable the precise conversion of targeted base changes without generating of double-strand breaks. However, both CBEs and ABEs induce substantial off-target DNA editing, and extensive off-target RNA single nucleotide variations in transfected cells. Therefore, the potential effects of deaminases induced by DNA base editors are of great importance for their clinical applicability. Here, the transcriptome-wide deaminase effects on gene expression and splicing is examined. Differentially expressed genes (DEGs) and differential alternative splicing (DAS) events, induced by base editors, are identified. Both CBEs and ABEs generated thousands of DEGs and hundreds of DAS events. For engineered CBEs or ABEs, base editor-induced variants had little effect on the elimination of DEGs and DAS events. Interestingly, more DEGs and DAS events are observed as a result of over expressions of cytosine and adenine deaminases. This study reveals a previously overlooked aspect of deaminase effects in transcriptome-wide gene expression and splicing, and underscores the need to fully characterize such effects of deaminase enzymes in base editor platforms.

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Specific Detection of Fasciola hepatica and F. gigantica in Infected Domesticated Animals Using High-Resolution Melting Analysis (HRM)

Iranian Journal of Public Health ◽

10.18502/ijph.v49i3.3149 ◽

2020 ◽

Author(s):

Zeinab MOGHADAMIZAD ◽

Ahmad HOSSEINI-SAFA ◽

Mehdi MOHEBALI ◽

Peyman HEYDARIAN ◽

Mojgan ARYAEIPOUR ◽

...

Keyword(s):

High Resolution ◽

High Resolution Melting ◽

Fasciola Hepatica ◽

High Resolution Melting Analysis ◽

Universal Primers ◽

Specific Primer ◽

Universal Primer ◽

Melting Analysis ◽

Liver Flukes ◽

Fasciola Spp

Background: It is difficult to make an exact morphological distinction between Fasciola hepatica and Fasciola gigantica. We used High Resolution Melting analysis (HRM) method to differentiate the F. hepatica species from F. gigantica in order to differentiate them. Methods: Overall, 80 adult liver flukes were collected from infected slaughtered animals including cattle, sheep and goats from Lorestan Province, western Iran from Sep 2015 to Aug 2017. Genomic DNA was extracted using commercial DNA extraction kit. The multilocus sequences of mDNA including COX1, COX3 and ND6 were amplified employing real-time PCR & HRM analysis. Specific and universal primer pairs were designed for differentiation Fasciola spp. Results: Universal primers cannot be used to distinguish between these two species, but in the contrary, specific primer pairs of each species could differentiate them properly. Molecular identification using specific primer pairs were consistent. Conclusion: HRM is a simple, fast and reliable method for detecting and differentiating F. hepatica from F. gigantica and can be used for diagnostic and epidemiological purposes.

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First report of Coleus blumei viroid 1 in commercial Coleus blumei in the United States

Plant Disease ◽

10.1094/pdis-05-21-0917-pdn ◽

2021 ◽

Author(s):

Gardenia Orellana ◽

Alexander V Karasev

Keyword(s):

United States ◽

Leaf Tissue ◽

The United States ◽

Universal Primers ◽

Rt Pcr ◽

Universal Primer ◽

Tissue Samples ◽

First Report ◽

Specific Pcr ◽

Coleus Blumei

Coleus scutellarioides (syn. Coleus blumei) is a widely grown evergreen ornamental plant valued for its highly decorative variegated leaves. Six viroids, named Coleus blumei viroid 1 to 6 (CbVd-1 to -6) have been identified in coleus plants in many countries of the world (Nie and Singh 2017), including Canada (Smith et al. 2018). However there have been no reports of Coleus blumei viroids occurring in the U.S.A. (Nie and Singh 2017). In April 2021, leaf tissue samples from 27 cultivars of C. blumei, one plant of each, were submitted to the University of Idaho laboratory from a commercial nursery located in Oregon to screen for the presence of viroids. The sampled plants were selected randomly and no symptoms were apparent in any of the samples. Total nucleic acids were extracted from each sample (Dellaporta et al. 1983) and used in reverse-transcription (RT)-PCR tests (Jiang et al. 2011) for the CbVd-1 and CbVd-5 with the universal primer pair CbVds-P1/P2, which amplifies the complete genome of all members in the genus Coleviroid (Jiang et al. 2011), and two additional primer pairs, CbVd1-F1/R1 and CbVd5-F1/R1, specific for CbVd-1 and CbVd-5, respectively (Smith et al. 2018). Five C. blumei plants (cvs Fire Mountain, Lovebird, Smokey Rose, Marrakesh, and Nutmeg) were positive for a coleviroid based on the observation of the single 250-nt band in the RT-PCR test with CbVds-P1/P2 primers. Two of these CbVd-1 positive plants (cvs Lovebird and Nutmeg) were also positive for CbVd-1 based on the presence of a single 150-nt band in the RT-PCR assay with CbVd1-F1/R1 primers. One plant (cv Jigsaw) was positive for CbVd-1, i.e. showing the 150-nt band in RT-PCR with CbVd1-F1/R1 primers, but did not show the ca. 250-bp band in RT-PCR with primers CbVds-P1/P2. None of the tested plants were positive for CbVd-5, either with the specific, or universal primers. All coleviroid- and CbVd-1-specific PCR products were sequenced directly using the Sanger methodology, and revealed whole genomes for five isolates of CbVd-1 from Oregon, U.S.A. The genomes of the five CbVd-1 isolates displayed 96.9-100% identity among each other and 96.0-100% identity to the CbVd-1 sequences available in GenBank. Because the sequences from cvs Lovebird, Marrakesh, and Nutmeg, were found 100% identical, one sequence was deposited in GenBank (MZ326145). Two other sequences, from cvs Fire Mountain and Smokey Rose, were deposited in the GenBank under accession numbers MZ326144 and MZ326146, respectively. To the best of our knowledge, this is the first report of CbVd-1 in the United States.

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Development of species-specific Cichla species eDNA primers for alien invasive species (AIS) monitoring in Malaysia

ARPHA Conference Abstracts ◽

10.3897/aca.4.e65449 ◽

2021 ◽

Vol 4 ◽

Author(s):

O. Nurul Fizatul Nabilah ◽

A. R. Ramizah ◽

A. B. Adibah ◽

S. Syazwan ◽

A.G. Intan Faraha ◽

...

Keyword(s):

Dna Sequences ◽

Environmental Dna ◽

Coi Gene ◽

Alien Invasive Species ◽

Survey Method ◽

Specific Primers ◽

Invasive Fishes ◽

Specific Amplification ◽

Species Specific ◽

High Level

Peacock bass or the cichlids are known locally as top predator fishes which are invasive in Malaysia freshwater system. Detection probabilities for these fishes are typically low, especially using conventional capture-survey method due to the fish’s behaviour of hiding beneath the water’s surface. Hence, the environmental DNA (eDNA) monitoring is a relatively new approach that can be used to assess the distribution of these invasive fishes. Here, we report the strategy to develop small fragment (280- 400 bp) specific-specific primers for three selected invasive Cichla species namely, C. ocellaris, C. monoculus, and C. kelberi based on mitochondrial DNA (mtDNA) sequences. Current research showed that the developed species-specific primers from cytochrome oxidase I (COI) gene has high resolution at species level. Species-specific amplification tests also proved the specificity of the developed primers, securing the high- level species identification potential which may help in controlling the spread of alien invasive fish species.

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Environmental DNA (eDNA) Metabarcoding in the Fish Market and Nearby Seafood Restaurants in Taiwan Reveals the Underestimation of Fish Species Diversity in Seafood

Biology ◽

10.3390/biology10111132 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1132

Author(s):

Hung-Tai Lee ◽

Cheng-Hsin Liao ◽

Te-Hua Hsu

Keyword(s):

Species Diversity ◽

Species Identification ◽

Fish Species ◽

Large Scale ◽

Environmental Dna ◽

Universal Primers ◽

Similar Species ◽

Operational Taxonomic Units ◽

Fish Market ◽

Fish Species Identification

Seafood, especially in traditional food Taiwan, is rarely sourced from a fixed species and routinely from similar species depending on their availability. Hence, the species composition of seafood can be complicated. While a DNA-based approach has been routinely utilized for species identification, a large scale of seafood identification in fish markets and restaurants could be challenging (e.g., elevated cost and time-consuming only for a limited number of species identification). In the present study, we aimed to identify the majority of fish species potentially consumed in fish markets and nearby seafood restaurants using environmental DNA (eDNA) metabarcoding. Four eDNA samplings from a local fish market and nearby seafood restaurants were conducted using Sterivex cartridges. Nineteen universal primers previously validated for fish species identification were utilized to amplify the fragments of mitochondrial DNA (12S, COI, ND5) of species in eDNA samples and sequenced with NovaSeq 6000 sequencing. A total of 153 fish species have been identified based on 417 fish related operational taxonomic units (OTUs) generated from 50,534,995 reads. Principal Coordinate Analysis (PCoA) further showed the differences in fish species between the sampling times and sampling sites. Of these fish species, 22 chondrichthyan fish, 14 Anguilliformes species, and 15 Serranidae species were respectively associated with smoked sharks, braised moray eels, and grouper fish soups. To our best knowledge, this work represents the first study to demonstrate the feasibility of a large scale of seafood identification using eDNA metabarcoding approach. Our findings also imply the species diversity in traditional seafood might be seriously underestimated and crucial for the conservation and management of marine resources.

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