ANNOTATING UniProt METAGENOMIC AND ENVIRONMENTAL SEQUENCES IN UniMES

2021 ◽  
Author(s):  
Aurelie Labarre ◽  
David López-Escardó ◽  
Francisco Latorre ◽  
Guy Leonard ◽  
François Bucchini ◽  
...  

AbstractHeterotrophic lineages of stramenopiles exhibit enormous diversity in morphology, lifestyle, and habitat. Among them, the marine stramenopiles (MASTs) represent numerous independent lineages that are only known from environmental sequences retrieved from marine samples. The core energy metabolism characterizing these unicellular eukaryotes is poorly understood. Here, we used single-cell genomics to retrieve, annotate, and compare the genomes of 15 MAST species, obtained by coassembling sequences from 140 individual cells sampled from the marine surface plankton. Functional annotations from their gene repertoires are compatible with all of them being phagocytotic. The unique presence of rhodopsin genes in MAST species, together with their widespread expression in oceanic waters, supports the idea that MASTs may be capable of using sunlight to thrive in the photic ocean. Additional subsets of genes used in phagocytosis, such as proton pumps for vacuole acidification and peptidases for prey digestion, did not reveal particular trends in MAST genomes as compared with nonphagocytotic stramenopiles, except a larger presence and diversity of V-PPase genes. Our analysis reflects the complexity of phagocytosis machinery in microbial eukaryotes, which contrasts with the well-defined set of genes for photosynthesis. These new genomic data provide the essential framework to study ecophysiology of uncultured species and to gain better understanding of the function of rhodopsins and related carotenoids in stramenopiles.


2005 ◽  
Vol 71 (10) ◽  
pp. 5935-5942 ◽  
Author(s):  
Marie Lefranc ◽  
Aurélie Thénot ◽  
Cécile Lepère ◽  
Didier Debroas

ABSTRACT Small eukaryotes, cells with a diameter of less than 5 μm, are fundamental components of lacustrine planktonic systems. In this study, small-eukaryote diversity was determined by sequencing cloned 18S rRNA genes in three libraries from lakes of differing trophic status in the Massif Central, France: the oligotrophic Lake Godivelle, the oligomesotrophic Lake Pavin, and the eutrophic Lake Aydat. This analysis shows that the least diversified library was in the eutrophic lake (12 operational taxonomic units [OTUs]) and the most diversified was in the oligomesotrophic lake (26 OTUs). Certain groups were present in at least two ecosystems, while the others were specific to one lake on the sampling date. Cryptophyta, Chrysophyceae, and the strictly heterotrophic eukaryotes, Ciliophora and fungi, were identified in the three libraries. Among the small eukaryotes found only in two lakes, Choanoflagellida and environmental sequences (LKM11) were not detected in the eutrophic system whereas Cercozoa were confined to the oligomesotrophic and eutrophic lakes. Three OTUs, linked to the Perkinsozoa, were detected only in the Aydat library, where they represented 60% of the clones of the library. Chlorophyta and Haptophyta lineages were represented by a single clone and were present only in Godivelle and Pavin, respectively. Of the 127 clones studied, classical pigmented organisms (autotrophs and mixotrophs) represented only a low proportion regardless of the library's origin. This study shows that the small-eukaryote community composition may differ as a function of trophic status; certain lineages could be detected only in a single ecosystem.


2020 ◽  
Vol 59 (2) ◽  
pp. 77-87
Author(s):  
Fernando Gómez ◽  
Luis F. Artigas ◽  
Rebecca J. Gast

The North Sea and the English Channel are regions with a long tradition of plankton studies, where the colony-forming haptophyte Phaeocystis globosa dominates the spring phytoplankton blooms. Among its predators, we investigated an abundant unarmored dinoflagellate (~3000 cells per liter) in the North Sea in May 2019. It has been reported in the literature as Gymnodinium heterostriatum or G. striatissimum, and often identified as Gyrodinium spirale. Phylogenetic analyses using the small-, large subunit- and Internal Transcriber Spacers of the ribosomal RNA (SSU-, LSU-, ITS rRNA) gene sequences indicate that our isolates clustered within the Gyrodinium clade. The new sequences formed a sister group with sequences of the freshwater taxon Gyrodinium helveticum, being one of the infrequent marine-freshwater transitions in the microbial world. This isolate is the first characterized member of a clade of numerous environmental sequences widely distributed from cold to tropical seas. This common and abundant taxon has received several names due to its morphological plasticity (changes of size and shape, often deformed after engulfing prey) and the difficulty in discerning surface striation. We conclude that the priority is for the species name Gymnodinium heterostriatum Kofoid & Swezy 1921, a new name that was proposed for Gymnodinium spirale var. obtusum sensu Dogiel 1906. The species Gyrodinium striatissimum (Hulburt 1957) Gert Hansen & Moestrup 2000 and Gymnodinium lucidum D. Ballantine in Parke & Dixon 1964 (=G. hyalinum M. Lebour 1925) are posterior synonyms. We propose Gyrodinium heterostriatum comb. nov. for Gymnodinium heterostriatum.


2019 ◽  
Vol 152 (3) ◽  
pp. 499-506 ◽  
Author(s):  
Oleg N. Shchepin ◽  
Martin Schnittler ◽  
Nikki H.A. Dagamac ◽  
Dmitry V. Leontyev ◽  
Yuri K. Novozhilov

Background and aims – Recent studies showed the position of two slime mould species with microscopic sporocarps, Echinosteliopsis oligospora and Echinostelium bisporum, within the class Myxomycetes. These minute species are seldom seen in studies based on detection of sporocarps and can easily be confused with protosteloid amoebozoans.Methods – We searched all published ePCR data sets that targeted myxomycete 18S rDNA for the presence of environmental sequences similar to E. oligospora and Echinosteliales in traditional circumscription, and performed phylogenetic analyses that included short environmental sequences and full-length 18S rDNA sequences representing all the major groups of myxomycetes.Key results – We report 19 unique sequences which are closely related to E. bisporum or E. oligospora based on sequence similarity (73.1–95.2% similarity) and which form well-supported monophyletic clades with these species in phylogenetic analyses. They may represent new species that are not yet described. Our phylogeny based on full-length 18S rDNA sequences further confirms the position of E. bisporum and E. oligospora within myxomycetes and the paraphyly of the order Echinosteliales in its traditional circumscription.Conclusions – Our results show that ePCR-based studies can reveal myxomycete taxa that often escape detection by traditional approaches, including potentially new species, and thus provide valuable new data on diversity and ecology of myxomycetes. As such, strategies for studying myxomycetes biodiversity should be revised, focusing also on molecular detection techniques in addition to the sporocarp-based ones.


2021 ◽  
Vol 4 ◽  
Author(s):  
Frederic Rimet ◽  
Teofana Chonova ◽  
Gilles Gassiole ◽  
Maria Kahlert ◽  
François Keck ◽  
...  

Diatoms (Bacillariophyta) are ubiquitous microalgae, which present a huge taxonomic diversity, changing in correlation with differing environmental conditions. This makes them excellent ecological indicators for various ecosystems and ecological problematics (ecotoxicology, biomonitoring, paleo-environmental reconstruction …). Current standardized methodologies for diatoms are based on microscopic determinations, which is time consuming and prone to identification uncertainties. DNA metabarcoding has been proposed as a way to avoid these flaws, enabling the sequencing of a large quantity of barcodes from natural samples. A taxonomic identity is given to these barcodes by comparing their sequences to a barcoding reference library. However, to identify environmental sequences correctly, the reference database should contain a representative number of reference sequences to ensure a good coverage of diatom diversity. Moreover, the reference database needs to be carefully taxonomically curated by experts, as its content has an obvious impact on species detection. Diat.barcode is an open-access library for diatoms linking diatom taxonomic identities to rbcL barcode sequences (a chloroplast marker suitable for species-level identification of diatoms), which has been maintained since 2012. Data are accumulated from three sources: (1) the NCBI nucleotide database, (2) unpublished sequencing data of culture collections and more recently (3) environmental sequences. Since 2017, an international network of experts in diatom taxonomy curate this library. The last version of the database (version 9.2), includes 8066 entries that correspond to more than 280 different genera and 1490 different species. In addition to the taxonomic information, morphological features (e.g. biovolumes, chloroplasts, etc.), life-forms (mobility, colony-type) and ecological features (taxa preferences to pollution) are given. The database can be downloaded from the website (www6.inrae.fr/carrtel-collection/Barcoding-database/) or directly through the R package diatbarcode. Ready-to-use files for commonly used metabarcoding pipelines (Mothur and DADA2) are also available.


MycoKeys ◽  
2018 ◽  
Vol 42 ◽  
pp. 35-72 ◽  
Author(s):  
Rachel A. Swenie ◽  
Timothy J. Baroni ◽  
P. Brandon Matheny

Five species of Hydnum have been generally recognized from eastern North America based on morphological recognition: H.albidum, H.albomagnum, H.repandum and varieties, H.rufescens, and H.umbilicatum. Other unique North American species, such as H.caespitosum and H.washingtonianum, are either illegitimately named or considered synonymous with European taxa. Here, seventeen phylogenetic species of Hydnum are detected from eastern North America based on a molecular phylogenetic survey of ITS sequences from herbarium collections and GenBank data, including environmental sequences. Based on current distribution results, sixteen of these species appear endemic to North America. Of these, six species are described as new: H.alboaurantiacum, H.cuspidatum, H.ferruginescens, H.subconnatum, H.subtilior, and H.vagabundum. Geographic range extensions and taxonomic notes are provided for five additional species recently described as new from eastern North America. A new name, H.geminum, is proposed for H.caespitosum Banning ex Peck, non Valenti. Overall, species of Hydnum are best recognized by a combination of morphological and molecular phylogenetic analyses. Taxonomic descriptions are provided for seventeen species, including epitype designations for H.albidum, H.albomagnum, and H.umbilicatum, taxa described more than 100 years ago, and molecular annotation of the isotype of H.washingtonianum. Photographs and a key to eastern North American Hydnum species are presented.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Frédéric Rimet ◽  
Evgenuy Gusev ◽  
Maria Kahlert ◽  
Martyn G. Kelly ◽  
Maxim Kulikovskiy ◽  
...  

Abstract Diatoms (Bacillariophyta) are ubiquitous microalgae which produce a siliceous exoskeleton and which make a major contribution to the productivity of oceans and freshwaters. They display a huge diversity, which makes them excellent ecological indicators of aquatic ecosystems. Usually, diatoms are identified using characteristics of their exoskeleton morphology. DNA-barcoding is an alternative to this and the use of High-Throughput-Sequencing enables the rapid analysis of many environmental samples at a lower cost than analyses under microscope. However, to identify environmental sequences correctly, an expertly curated reference library is needed. Several curated libraries for protists exists; none, however are dedicated to diatoms. Diat.barcode is an open-access library dedicated to diatoms which has been maintained since 2012. Data come from two sources (1) the NCBI nucleotide database and (2) unpublished sequencing data of culture collections. Since 2017, several experts have collaborated to curate this library for rbcL, a chloroplast marker suitable for species-level identification of diatoms. For the latest version of the database (version 7), 605 of the 3482 taxonomical names originally assigned by the authors of the rbcL sequences were modified after curation. The database is accessible at https://www6.inra.fr/carrtel-collection_eng/Barcoding-database.


2020 ◽  
Vol 298 (3) ◽  
pp. 285-309
Author(s):  
Forough Abasaghi ◽  
Asadollah Mahboubi ◽  
Mohammad Hosein Mahmoudi Gharaie ◽  
Mohammad Khanehbad

Zoophycos is widely distributed in the marine strata of the Middle Permian Ruteh For- mation in the Alborz Mountain, Iran. The investigation of the Zoophycos, along with environmental variables is a useful tool for interpretation of the palaeoenvironmental and sequence stratigraphy anal- ysis. The petrographic observations led to the identification of ten facies in four facies belts including tidal flat, lagoon, shoal, and open marine, deposited on a homoclinal ramp. Moreover, two third- order depositional sequences were recognized in response to the sea- level fluctuations within the Ruteh For - mation. Detailed studies of the sequence stratigraphy revealed a relationship between the occurrences of Zoophycos and changes in the hydrodynamic condition in the basin. It appears that Zoophycos has been influenced by the ecological and palaeoenvironmental parameters, such as sedimentation rate, nutrient supply, oxygen, wave base, and substrate in the shallow to deep environments. Based on the sedimentological and ichnological analysis, Zoophycos has been formed with various dimensions, morphology, fillings, and densities together with rising and falling in the sea-level. The trace- maker has followed an opportunistic strategy in the unstable conditions of shallow environments, whereas it has chosen a k-selected strategy in more stable deep environments. Additionally, variability in Zoophycos illustrates, how the trace- maker adopted itself with environmental sequences. This reason, owing to optimal conditions, has caused that the abundance of Zoophycos was high in the Transgres- sive System Tracts (TST). Evidence shows that the response of Zoophycos to the ecological properties of the environment usually has deposit- feeder and chemosymbiosis behaviours.


Botany ◽  
2014 ◽  
Vol 92 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Maarja Öpik ◽  
John Davison ◽  
Mari Moora ◽  
Martin Zobel

An increasing number of case studies are reporting Glomeromycota molecular diversity from ecosystems worldwide. Typically, phylogroups that can be related to morphospecies and those that remain unidentified (“environmental”) are recorded. To compare such data and generalise observed patterns, the principles underlying sequence identification should be unified. Data from case studies are collected and systematized in a public database MaarjAM ( http://www.maarjam.botany.ut.ee ), which applies a unique molecular operational taxonomic unit (MOTU) nomenclature: virtual taxa (VT) are phylogenetically defined sequence groups roughly corresponding to species-level taxa. VT are based on type sequences, making them consistent in time, but they also evolve: they can be split or merged, when necessary. This system allows standardisation of original MOTU designations and, much like binomial taxonomic nomenclature, comparison and consistency between studies. Refinement of VT delimitation principles and comparability with traditional Glomeromycota taxonomy will benefit from more information about intra- vs. inter-specific nucleotide variation in Glomeromycota, sequencing of morphospecies, and resolution of issues in Glomeromycota taxonomy. As the recorded number of VT already exceeds the number of Glomeromycota morphospecies, designation of species based on DNA alone appears a necessity in the near future. Application of VT is becoming widespread, and MaarjAM database is increasingly used as a reference for environmental sequence identification. The current status and future prospects of arbuscular mycorrhizal fungi (AMF) DNA-based identification and community description are presented.


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