scholarly journals Censusing marine eukaryotic diversity in the twenty-first century

2016 ◽  
Vol 371 (1702) ◽  
pp. 20150331 ◽  
Author(s):  
Matthieu Leray ◽  
Nancy Knowlton
Keyword(s):  
High Throughput Sequencing ◽  
Pcr Amplification ◽  
Global Ocean ◽  
Taxonomic Resolution ◽  
Molecular Technique ◽  
Homologous Gene ◽  
Variable Regions ◽  
Eukaryotic Diversity ◽  
Eukaryotic Species ◽  
Taxonomic Groups

The ocean constitutes one of the vastest and richest biomes on our planet. Most recent estimations, all based on indirect approaches, suggest that there are millions of marine eukaryotic species. Moreover, a large majority of these are small (less than 1 mm), cryptic and still unknown to science. However, this knowledge gap, caused by the lack of diagnostic morphological features in small organisms and the limited sampling of the global ocean, is currently being filled, thanks to new DNA-based approaches. The molecular technique of PCR amplification of homologous gene regions combined with high-throughput sequencing, routinely used to census unculturable prokaryotes, is now also being used to characterize whole communities of marine eukaryotes. Here, we review how this methodological advancement has helped to better quantify the magnitude and patterns of marine eukaryotic diversity, with an emphasis on taxonomic groups previously largely overlooked. We then discuss obstacles remaining to achieve a global understanding of marine eukaryotic diversity. In particular, we argue that 18S variable regions do not provide sufficient taxonomic resolution to census marine life, and suggest combining broad eukaryotic surveys targeting the 18S rRNA region with more taxon-focused analyses of hypervariable regions to improve our understanding of the diversity of species, the functional units of marine ecosystems. This article is part of the themed issue ‘From DNA barcodes to biomes’.

Molecular characterization and structure of intestinal micro flora for postmortem interval estimation in SD rats

2019 ◽  
Author(s):  
Huan Li ◽  
Lu Yuan ◽  
Ruina Liu ◽  
Siruo Zhang ◽  
E Yang ◽  
...  
Keyword(s):  
Bacterial Community ◽  
High Throughput Sequencing ◽  
Interval Estimation ◽  
Pcr Amplification ◽  
Postmortem Interval ◽  
The Body ◽  
Rrna Gene ◽  
Variable Regions ◽  
Time Points ◽  
Almost All

Abstract Background The human rectum flora consists of a huge variety of bacteria and the association between individuals and their rectum bacterial community begins presently after birth and continues the whole lifetime. Once the body dies, the inherent microbes begin to break down from the inside and play a key role thereafter. Results The aim of this study was to investigate the probable shift of the rectum flora at different time intervals up to 15 days after death and to characterize the contribution for of this shift to estimate the time of death. The rectum of rats was wiped with a sterile cotton swab and the samples were proceeded for DNA extraction, PCR amplification of the 16S rRNA gene with the V3+V4 variable regions, and high throughput sequencing carried out on IonS5TMXL platform. The results were analyzed for intra-group and inter-group diversity, similarity and difference at different time points. At phylum level, Proteobacteria and Firmicutes showed major shifts, checked at 11 different intervals and emerged in the most of postmortem intervals. At the genus level, Enterococcus appeared in all groups except alive samples, Lactobacillus and Proteus appeared in most time points, and the latter showed an increasing trend after 3 days postmortem samples. At the species level, Enterococcus_faecalis and Proteus_mirabilis existed in most postmortem intervals, and the former had a downward trend after day 5 postmortem, while the latter had an upward trend. Corynebacterium_amycolatum , Entero_isolate_group_2 , Bacteroides_uniformis , Enterococcus_faecalis , Streptococcus_gallolyticus_subsp_macedonics , Clostridium_sporogenes were more abundant in 0-hour, day 1, 3, 5, 7, 13 postmortem intervals, respectively, while Proteus_mirabilis and Vagococcus_lutrae were abundant in day 15 postmortem. In addition, functional capacity analysis of Membrane_Transport, Amino_Acid_Metabolism, Nucleotide_Metabolism and Energy_Metabolism showed significant differences between alive and almost all other time points after death ( P <0.05). Conclusions All in all, bacteria at different levels (phylum, genera, species) showed different characteristic during the process of decomposition and possessed entirely different relative abundance and the structure of bacterial community in each time point shifted obviously, which suggested that the specific bacteria might imply the specific postmortem interval during decomposition.

scholarly journals Evaluation of 16S rRNA gene sequencing for species and strain-level microbiome analysis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jethro S. Johnson ◽  
Daniel J. Spakowicz ◽  
Bo-Young Hong ◽  
Lauren M. Petersen ◽  
Patrick Demkowicz ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
High Throughput Sequencing ◽  
Full Length ◽  
Strain Level ◽  
Taxonomic Resolution ◽  
Rrna Gene ◽  
Variable Regions ◽  
16S Gene ◽  
Sequencing Platforms

Abstract The 16S rRNA gene has been a mainstay of sequence-based bacterial analysis for decades. However, high-throughput sequencing of the full gene has only recently become a realistic prospect. Here, we use in silico and sequence-based experiments to critically re-evaluate the potential of the 16S gene to provide taxonomic resolution at species and strain level. We demonstrate that targeting of 16S variable regions with short-read sequencing platforms cannot achieve the taxonomic resolution afforded by sequencing the entire (~1500 bp) gene. We further demonstrate that full-length sequencing platforms are sufficiently accurate to resolve subtle nucleotide substitutions (but not insertions/deletions) that exist between intragenomic copies of the 16S gene. In consequence, we argue that modern analysis approaches must necessarily account for intragenomic variation between 16S gene copies. In particular, we demonstrate that appropriate treatment of full-length 16S intragenomic copy variants has the potential to provide taxonomic resolution of bacterial communities at species and strain level.

scholarly journals Marked changes in diversity and relative activity of picoeukaryotes with depth in the global ocean

2019 ◽  
Author(s):  
Caterina R. Giner ◽  
Vanessa Balagué ◽  
Massimo C. Pernice ◽  
Carlos M. Duarte ◽  
Josep M. Gasol ◽  
...  
Keyword(s):  
Community Structure ◽  
Water Column ◽  
High Throughput Sequencing ◽  
Hot Spot ◽  
18S Rrna Gene ◽  
Relative Activity ◽  
Global Ocean ◽  
Rrna Gene ◽  
M Cell ◽  
Taxonomic Groups

ABSTRACTMicrobial eukaryotes are key components of the ocean plankton. Yet, our understanding of their community composition and activity in different water layers of the ocean is limited, particularly for picoeukaryotes (0.2-3µm cell size). Here we examined the picoeukaryotic communities inhabiting different vertical zones of the tropical and subtropical global ocean: surface, deep chlorophyll maximum, mesopelagic (including the deep scattering layer and minimum oxygen zone) and bathypelagic. Communities were analysed by high-throughput sequencing of the 18S rRNA gene, as represented by DNA (community structure) and RNA (metabolic expression), followed by delineation of Operational Taxonomic Units (OTUs). We found a clear stratification of the picoeukaryotic communities along the water column, with two differentiated assemblages corresponding to the sunlit and dark ocean. Specific taxonomic groups either increased or decreased their abundances with depth. We used the rRNA:rDNA ratio of each individual OTU as a proxy of its metabolic activity. The highest relative activity was found in the mesopelagic layer for most taxonomic groups, and the lowest in the bathypelagic. Overall, our results characterize the change in community structure and activity of picoeukaryotes in the global-ocean water column, suggesting that the mesopeagic layer is a hot-spot of picoeukaryotic activity.

scholarly journals Metagenomic analysis of orange colored protrusions from the muscle of Queen ConchLobatus gigas(Linnaeus, 1758)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4307 ◽  
Author(s):  
Jaison H. Cuartas ◽  
Juan F. Alzate ◽  
Claudia X. Moreno-Herrera ◽  
Edna J. Marquez
Keyword(s):  
Conservation Status ◽  
Pcr Amplification ◽  
Caribbean Region ◽  
Molecular Technique ◽  
Fishery Resource ◽  
Ecological Fitness ◽  
Molecular Approaches ◽  
The Caribbean ◽  
Assignment Analysis ◽  
Taxonomic Groups

The endangered marine gastropod,Lobatus gigas,is an important fishery resource in the Caribbean region. Microbiological and parasitological research of this species have been poorly addressed despite its role in ecological fitness, conservation status and prevention of potential pathogenic infections. This study identified taxonomic groups associated with orange colored protrusions in the muscle of queen conchs using histological analysis, 454 pyrosequencing, and a combination of PCR amplification and automated Sanger sequencing. The molecular approaches indicate that the etiological agent of the muscle protrusions is a parasite belonging to the subclass Digenea. Additionally, the scope of the molecular technique allowed the detection of bacterial and fungi clades in the assignment analysis. This is the first evidence of a digenean infection in the muscle of this valuable Caribbean resource.

DETECTION OF ALFACORONAVIRUSES, BETACORONAVIRUSES AND ASTROVIRUSES IN BAT FECAL SAMPLES FROM MOSCOW REGION

2020 ◽  
Author(s):  
E.V. Korneenko ◽  
◽  
А.E. Samoilov ◽  
I.V. Artyushin ◽  
M.V. Safonova ◽  
...  
Keyword(s):  
High Throughput ◽  
Viral Genome ◽  
High Throughput Sequencing ◽  
Pcr Amplification ◽  
Moscow Region ◽  
Fecal Samples ◽  
Genus Level ◽  
Zoonotic Viruses ◽  
Reservoir Hosts ◽  
Blastn Search

In our study we analyzed viral RNA in bat fecal samples from Moscow region (Zvenigorod district) collected in 2015. To detect various virus families and genera in bat fecal samples we used PCR amplification of viral genome fragments, followed by high-throughput sequencing. Blastn search of unassembled reads revealed the presence of viruses from families Astroviridae, Coronaviridae and Herpesviridae. Assembly using SPAdes 3.14 yields contigs of length 460–530 b.p. which correspond to genome fragments of Coronaviridae and Astroviridae. The taxonomy of coronaviruses has been determined to the genus level. We also showed that one bat can be a reservoir of several virus genuses. Thus, the bats in the Moscow region were confirmed as reservoir hosts for potentially zoonotic viruses.

scholarly journals Toward a global reference database of COI barcodes for marine zooplankton

2021 ◽  
Vol 168 (6) ◽  
Author(s):  
Ann Bucklin ◽  
Katja T. C. A. Peijnenburg ◽  
Ksenia N. Kosobokova ◽  
Todd D. O’Brien ◽  
Leocadio Blanco-Bercial ◽  
...  
Keyword(s):  
Species Diversity ◽  
Dna Sequences ◽  
Reference Sequence ◽  
Global Ocean ◽  
Reference Database ◽  
Data Repositories ◽  
Marine Zooplankton ◽  
The North ◽  
Coi Sequences ◽  
Taxonomic Groups

AbstractCharacterization of species diversity of zooplankton is key to understanding, assessing, and predicting the function and future of pelagic ecosystems throughout the global ocean. The marine zooplankton assemblage, including only metazoans, is highly diverse and taxonomically complex, with an estimated ~28,000 species of 41 major taxonomic groups. This review provides a comprehensive summary of DNA sequences for the barcode region of mitochondrial cytochrome oxidase I (COI) for identified specimens. The foundation of this summary is the MetaZooGene Barcode Atlas and Database (MZGdb), a new open-access data and metadata portal that is linked to NCBI GenBank and BOLD data repositories. The MZGdb provides enhanced quality control and tools for assembling COI reference sequence databases that are specific to selected taxonomic groups and/or ocean regions, with associated metadata (e.g., collection georeferencing, verification of species identification, molecular protocols), and tools for statistical analysis, mapping, and visualization. To date, over 150,000 COI sequences for ~ 5600 described species of marine metazoan plankton (including holo- and meroplankton) are available via the MZGdb portal. This review uses the MZGdb as a resource for summaries of COI barcode data and metadata for important taxonomic groups of marine zooplankton and selected regions, including the North Atlantic, Arctic, North Pacific, and Southern Oceans. The MZGdb is designed to provide a foundation for analysis of species diversity of marine zooplankton based on DNA barcoding and metabarcoding for assessment of marine ecosystems and rapid detection of the impacts of climate change.

scholarly journals PCR amplification of antibody variable regions using primers that anneal to constant regions

1994 ◽  
Vol 22 (9) ◽  
pp. 1768-1769 ◽  
Author(s):  
Marica Sassano ◽  
Monica Repetto ◽  
Giovanni Cassani ◽  
Angelo Corti
Keyword(s):  
Pcr Amplification ◽  
Variable Regions

scholarly journals Ligation-anchored PCR unveils immune repertoire of TCR-beta from whole blood

2014 ◽  
Author(s):  
Fan Gao ◽  
Kai Wang
Keyword(s):  
High Throughput Sequencing ◽  
Read Length ◽  
Integrative Approach ◽  
Sequencing Data ◽  
Immune Repertoire ◽  
Universal Primer ◽  
Illumina Hiseq ◽  
Variable Regions ◽  
Anchored Pcr ◽  
Pcr Method

Background As one of the genetic mechanisms for adaptive immunity, V(D)J recombination generates an enormous repertoire of T-cell receptors (TCRs). With the development of high-throughput sequencing techniques, systematic exploration of V(D)J recombination becomes possible. Multiplex PCR method has been previously developed to assay immune repertoire, however the usage of primer pools has inherent bias in target amplification. In our study, we developed a ligation-anchored PCR method to unbiasedly amplify the repertoire. Results By utilizing a universal primer paired with a single primer targeting the conserved constant region, we amplified TCR-beta (TRB) variable regions from total RNA extracted from blood. Next-generation sequencing libraries were then prepared for Illumina HiSeq 2500 sequencer, which provided 151 bp read length to cover the entire V(D)J recombination region. We evaluated this approach on blood samples from patients with malignant and benign meningiomas. Mapping of sequencing data showed 64% to 91% of mapped TCRV-containing reads belong to TRB subtype. An increased usage of TRBV29-1 was observed in malignant meningiomas. Also distinct signatures were identified from CDR3 sequence logos, with predominant subset as 42 nt for benign and 45 nt for malignant samples, respectively. Conclusions In summary, we report an integrative approach to monitor immune repertoire in a systematic manner.

scholarly journals The use of eDNA and DNA metabarcoding in monitoring the ecological condition of Norwegian lakes

2021 ◽  
Vol 4 ◽  
Author(s):  
Sara Atienza Casas ◽  
Markus Majaneva ◽  
Thomas Jensen ◽  
Marie Davey ◽  
Frode Fossøy ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Ecological Status ◽  
Ecological Condition ◽  
Molecular Techniques ◽  
Taxonomic Resolution ◽  
Potential Cost ◽  
Running Water ◽  
National Monitoring ◽  
Monitoring Programs ◽  
Dna Metabarcoding

Biodiversity assessments using molecular identification of organisms through high-throughput sequencing techniques have been a game changer in ecosystem monitoring, providing increased taxonomic resolution, more objective identifications, potential cost reductions, and reduced processing times. The use of DNA metabarcoding of bulk samples and environmental DNA (eDNA) is now widespread but is not yet universally implemented in national monitoring programs. While bulk sample metabarcoding involves extraction of DNA from organisms in a sample, eDNA analysis involves obtaining DNA directly from environmental samples, which can include microorganisms, meiofauna-size taxa and macrofauna traces such as larval stages, skin and hair cells, gametes, faeces and free DNA bound to particles. In Norway, freshwater biomonitoring in compliance with the EU Water Framework Directive (WFD) is conducted on several administrative levels, including national monitoring programs for running water, small and large lakes. These programs typically focus on a fraction of the actual biodiversity present in the monitored habitats (Weigand 2019). DNA metabarcoding of both bulk samples and eDNA samples are relevant tools for future freshwater biomonitoring in Norway. The aim of this PhD project is to develop assessment protocols based on DNA-metabarcoding and eDNA of benthic invertebrates, microcrustaceans and fish that can be used as standard biomonitoring tools to assess the ecological condition of lakes. The main topics addressed will be: - Development of protocols throughout the eDNA-metabarcoding workflow (i.e. sampling, filtration, preservation, extraction, amplification and sequencing) suitable to execute biodiversity assessments and determine the ecological status of lakes. - Comparison of the results obtained using molecular tools and traditional morphology-based approaches in order to assess the feasibility of such techniques to be incorporated as standard biomonitoring tools, such as the ones implemented under the provisions of the WFD. - Evaluate the effect of improved taxonomic resolution from molecular techniques on determining the ecological status of lakes, both by broadening the number of taxa analyzed and by identifying more taxa to species level. - Assess the feasibility of using eDNA extracted from water samples, taken at different depths and fish densities, to measure fish abundance/biomass as a proxy to calculate the ecological quality indices regulated in the WFD. - Analyze the coverage and resolution provided by reference libraries for certain taxa, such as crustacea, in order to assess the reliability and precision of taxonomic assignments.

scholarly journals Selection and Identification of Novel Aptamers Specific for Clenbuterol Based on ssDNA Library Immobilized SELEX and Gold Nanoparticles Biosensor

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2337 ◽  
Author(s):  
Xixia Liu ◽  
Qi Lu ◽  
Sirui Chen ◽  
Fang Wang ◽  
Jianjun Hou ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Limit Of Detection ◽  
Retention Rate ◽  
Pcr Amplification ◽  
Cross Reactivity ◽  
Enriched Library ◽  
Amplification Curve ◽  
Specificity And Sensitivity

We describe a multiple combined strategy to discover novel aptamers specific for clenbuterol (CBL). An immobilized ssDNA library was used for the selection of specific aptamers using the systematic evolution of ligands by exponential enrichment (SELEX). Progress was monitored using real-time quantitative PCR (Q-PCR), and the enriched library was sequenced by high-throughput sequencing. Candidate aptamers were picked and preliminarily identified using a gold nanoparticles (AuNPs) biosensor. Bioactive aptamers were characterized for affinity, circular dichroism (CD), specificity and sensitivity. The Q-PCR amplification curve increased and the retention rate was about 1% at the eighth round. Use of the AuNPs biosensor and CD analyses determined that six aptamers had binding activity. Affinity analysis showed that aptamer 47 had the highest affinity (Kd = 42.17 ± 8.98 nM) with no cross reactivity to CBL analogs. Indirect competitive enzyme linked aptamer assay (IC-ELAA) based on a 5′-biotin aptamer 47 indicated the limit of detection (LOD) was 0.18 ± 0.02 ng/L (n = 3), and it was used to detect pork samples with a mean recovery of 83.33–97.03%. This is the first report of a universal strategy including library fixation, Q-PCR monitoring, high-throughput sequencing, and AuNPs biosensor identification to select aptamers specific for small molecules.

Sign in / Sign up

Export Citation Format

Share Document