scholarly journals Diversity and substrate-specificity of green algae and other micro-eukaryotes colonizing amphibian clutches in Germany, revealed by DNA metabarcoding

2021 ◽  
Vol 108 (4) ◽  
Author(s):  
Sten Anslan ◽  
Maria Sachs ◽  
Lois Rancilhac ◽  
Henner Brinkmann ◽  
Jörn Petersen ◽  
...  
Keyword(s):  
Green Algae ◽  
Phylogenetic Analyses ◽  
Sampling Location ◽  
Operational Taxonomic Units ◽  
Clade B ◽  
Unicellular Green Alga ◽  
Dna Metabarcoding ◽  
Oophila Amblystomatis ◽  
Micro Organisms ◽  
Rana Dalmatina

AbstractAmphibian clutches are colonized by diverse but poorly studied communities of micro-organisms. One of the most noted ones is the unicellular green alga, Oophila amblystomatis, but the occurrence and role of other micro-organisms in the capsular chamber surrounding amphibian clutches have remained largely unstudied. Here, we undertook a multi-marker DNA metabarcoding study to characterize the community of algae and other micro-eukaryotes associated with agile frog (Rana dalmatina) clutches. Samplings were performed at three small ponds in Germany, from four substrates: water, sediment, tree leaves from the bottom of the pond, and R. dalmatina clutches. Sampling substrate strongly determined the community compositions of algae and other micro-eukaryotes. Therefore, as expected, the frog clutch-associated communities formed clearly distinct clusters. Clutch-associated communities in our study were structured by a plethora of not only green algae, but also diatoms and other ochrophytes. The most abundant operational taxonomic units (OTUs) in clutch samples were taxa from Chlamydomonas, Oophila, but also from Nitzschia and other ochrophytes. Sequences of Oophila “Clade B” were found exclusively in clutches. Based on additional phylogenetic analyses of 18S rDNA and of a matrix of 18 nuclear genes derived from transcriptomes, we confirmed in our samples the existence of two distinct clades of green algae assigned to Oophila in past studies. We hypothesize that “Clade B” algae correspond to the true Oophila, whereas “Clade A” algae are a series of Chlorococcum species that, along with other green algae, ochrophytes and protists, colonize amphibian clutches opportunistically and are often cultured from clutch samples due to their robust growth performance. The clutch-associated communities were subject to filtering by sampling location, suggesting that the taxa colonizing amphibian clutches can drastically differ depending on environmental conditions.

scholarly journals Environmental DNA metabarcoding of rivers: Not all eDNA is everywhere, and not all the time

2017 ◽  
Author(s):  
Jan-Niklas Macher ◽  
Florian Leese
Keyword(s):  
Surface Water ◽  
Abiotic Factors ◽  
Sampling Site ◽  
Environmental Dna ◽  
Side Surface ◽  
Illumina Miseq ◽  
Sampling Location ◽  
Freshwater Biodiversity ◽  
Operational Taxonomic Units ◽  
Dna Metabarcoding

AbstractEnvironmental DNA metabarcoding has become a popular tool for the assessment of freshwater biodiversity, but it is largely unclear how sampling time and location influence the assessment of communities. Abiotic factors in rivers can change on small spatial and temporal scale and might greatly influence eDNA metabarcoding results. In this study, we sampled three German rivers at four locations per sampling site: 1. Left river side, surface water 2. Right river side, surface water, 3. Left side, close to the riverbed, 4. Right side, close to the riverbed. For the rivers Ruhr and Möhne, sampling was conducted three times in spring, each sampling one week apart. The Ruhr was again sampled in autumn and the Gillbach was sampled in winter. Sequencing on an Illumina MiSeq with COI primers Bf2/BR2 revealed diverse communities (6493 Operational taxonomic units, OTUs), which largely differed between rivers. Communities changed significantly over time in the Ruhr, but not in the Möhne. Sampling location influenced recovered communities in the Möhne and in the Ruhr in autumn. Our results have important implications for future eDNA studies, which should take into account that not all eDNA in rivers is everywhere and not at all times.

Freshwater Perkinsea: diversity, ecology and genomic information

2019 ◽  
Vol 42 (1) ◽  
pp. 3-17 ◽  
Author(s):  
M Jobard ◽  
I Wawrzyniak ◽  
G Bronner ◽  
D Marie ◽  
A Vellet ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Meta Analysis ◽  
Freshwater Ecosystems ◽  
Protein Coding ◽  
Lake Ecosystems ◽  
Operational Taxonomic Units ◽  
Clade 1 ◽  
Almost All ◽  
Parasitic Association

Abstract Studies on freshwater Perkinsea are scarce compared to their marine counterparts; they are therefore not well ecologically characterized. In this study, we investigated the diversity, distribution and ecological role of Perkinsea in freshwater ecosystems. Our approach included (1) the phylogenetic analyses of near full-length SSU and LSU sequences of freshwater Perkinsea, (2) a meta-analysis of public Perkinsea 18S ribosomal RNA gene sequences available from the freshwater environments (25 lakes, 4 rivers), (3) microscopic observations of Perkinsea associated with planktonic communities and (4) single amplified genome analysis. Whereas Perkinsea appear to be rare in river ecosystems (85 reads), they are found in almost all of the lakes studied. However, their diversity does vary considerably between lakes (from 0 to 2 463 Operational Taxonomic Units (OTUs)). Phylogenetic analysis showed that the Parvilucifera/Dinovorax/Snorkelia and Perkinsus/Xcellia/Gadixcellia clades resulted from an initial speciation event. This second clade is further split into well-supported, monophyletic groups, including a clade dominated by freshwater representatives, which is further structured into three distinct subclades: freshwater clade 1, freshwater clade 2 and a freshwater and brackish clade. The Perkinsea Single Amplified Genome (SAG) as well as most of the abundant Operational Taxonomic Units (OTUs) fall into freshwater clade 2. The tyramide signal amplification-fluorescent in situ hybridization method showed an internal association between Perkinsea and the colonial phytoplankton Sphaerocystis. The Single Amplified Genome (SAG) annotation contained 698 genes and gene ontology terms could be assigned to 486 protein-coding genes. Although the number of genes appears to be low (10.6% of the entire gene set assessed by BUSCO), the analysis of the proteome revealed some putative secreted virulence factors. This study showed a large distribution of Perkinsea across lake ecosystems and potential parasitic association with phytoplankton. However, further investigations are needed for a better knowledge on the role of these microorganisms in freshwater ecosystems.

scholarly journals Fungia fungites (Linnaeus, 1758) (Scleractinia, Fungiidae) is a species complex that conceals large phenotypic variation and a previously unrecognized genus

2020 ◽  
Vol 89 (2) ◽  
pp. 188-209
Author(s):  
Yutaro Oku ◽  
Kenji Iwao ◽  
Bert W. Hoeksema ◽  
Naoko Dewa ◽  
Hiroyuki Tachikawa ◽  
...  
Keyword(s):  
Species Complex ◽  
Phylogenetic Analyses ◽  
Molecular Data ◽  
Scleractinian Corals ◽  
Type Specimens ◽  
Mitochondrial Coi ◽  
Clade B ◽  
Unknown Species ◽  
Molecular Phylogenetic ◽  
Morphological Differences

Recent molecular phylogenetic analyses of scleractinian corals have resulted in the discovery of cryptic lineages. To understand species diversity in corals, these lineages need to be taxonomically defined. In the present study, we report the discovery of a distinct lineage obscured by the traditional morphological variation of Fungia fungites. This taxon exists as two distinct morphs: attached and unattached. Molecular phylogenetic analyses using mitochondrial COI and nuclear ITS markers as well as morphological comparisons were performed to clarify their phylogenetic relationships and taxonomic positions. Molecular data revealed that F. fungites consists of two genetically distinct clades (A and B). Clade A is sister to a lineage including Danafungia scruposa and Halomitra pileus, while clade B formed an independent lineage genetically distant from these three species. The two morphs were also found to be included in both clades, although the attached morph was predominantly found in clade A. Morphologically, both clades were statistically different in density of septal dentation, septal number, and septal teeth shape. These results indicate that F. fungites as presently recognized is actually a species complex including at least two species. After checking type specimens, we conclude that specimens in clade A represent true F. fungites with two morphs (unattached and attached) and that all of those in clade B represent an unknown species and genus comprising an unattached morph with only one exception. These findings suggest that more unrecognized taxa with hitherto unnoticed morphological differences can be present among scleractinian corals.

scholarly journals Novel Cell-Virus-Virophage Tripartite Infection Systems Discovered in the Freshwater Lake Dishui Lake in Shanghai, China

2020 ◽  
Vol 94 (11) ◽  
Author(s):  
Shengzhong Xu ◽  
Liang Zhou ◽  
Xiaosha Liang ◽  
Yifan Zhou ◽  
Hao Chen ◽  
...  
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Phylogenetic Analyses ◽  
Freshwater Lake ◽  
Metagenomic Data ◽  
Data Sets ◽  
Data Set ◽  
Dna Viruses ◽  
Oligonucleotide Frequency ◽  
Dsdna Viruses

ABSTRACT Virophages are small parasitic double-stranded DNA (dsDNA) viruses of giant dsDNA viruses infecting unicellular eukaryotes. Except for a few isolated virophages characterized by parasitization mechanisms, features of virophages discovered in metagenomic data sets remain largely unknown. Here, the complete genomes of seven virophages (26.6 to 31.5 kbp) and four large DNA viruses (190.4 to 392.5 kbp) that coexist in the freshwater lake Dishui Lake, Shanghai, China, have been identified based on environmental metagenomic investigation. Both genomic and phylogenetic analyses indicate that Dishui Lake virophages (DSLVs) are closely related to each other and to other lake virophages, and Dishui Lake large DNA viruses are affiliated with the micro-green alga-infecting Prasinovirus of the Phycodnaviridae (named Dishui Lake phycodnaviruses [DSLPVs]) and protist (protozoan and alga)-infecting Mimiviridae (named Dishui Lake large alga virus [DSLLAV]). The DSLVs possess more genes with closer homology to that of large alga viruses than to that of giant protozoan viruses. Furthermore, the DSLVs are strongly associated with large green alga viruses, including DSLPV4 and DSLLAV1, based on codon usage as well as oligonucleotide frequency and correlation analyses. Surprisingly, a nonhomologous CRISPR-Cas like system is found in DSLLAV1, which appears to protect DSLLAV1 from the parasitization of DSLV5 and DSLV8. These results suggest that novel cell-virus-virophage (CVv) tripartite infection systems of green algae, large green alga virus (Phycodnaviridae- and Mimiviridae-related), and virophage exist in Dishui Lake, which will contribute to further deep investigations of the evolutionary interaction of virophages and large alga viruses as well as of the essential roles that the CVv plays in the ecology of algae. IMPORTANCE Virophages are small parasitizing viruses of large/giant viruses. To our knowledge, the few isolated virophages all parasitize giant protozoan viruses (Mimiviridae) for propagation and form a tripartite infection system with hosts, here named the cell-virus-virophage (CVv) system. However, the CVv system remains largely unknown in environmental metagenomic data sets. In this study, we systematically investigated the metagenomic data set from the freshwater lake Dishui Lake, Shanghai, China. Consequently, four novel large alga viruses and seven virophages were discovered to coexist in Dishui Lake. Surprisingly, a novel CVv tripartite infection system comprising green algae, large green alga viruses (Phycodnaviridae- and Mimiviridae-related), and virophages was identified based on genetic link, genomic signature, and CRISPR system analyses. Meanwhile, a nonhomologous CRISPR-like system was found in Dishui Lake large alga viruses, which appears to protect the virus host from the infection of Dishui Lake virophages (DSLVs). These findings are critical to give insight into the potential significance of CVv in global evolution and ecology.

scholarly journals Inter-domain microbial diversity within the coral holobiontSiderastrea sidereafrom two depth habitats

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4323 ◽  
Author(s):  
Guido Bonthond ◽  
Daniel G. Merselis ◽  
Katherine E. Dougan ◽  
Trevor Graff ◽  
William Todd ◽  
...  
Keyword(s):  
Florida Keys ◽  
Amplicon Sequencing ◽  
Fungal Communities ◽  
Physiological Adaptation ◽  
Operational Taxonomic Units ◽  
Clade B ◽  
Holistic Understanding ◽  
Clade C ◽  
Occurrence Patterns ◽  
High Degree

Corals host diverse microbial communities that are involved in acclimatization, pathogen defense, and nutrient cycling. Surveys of coral-associated microbes have been particularly directed towardSymbiodiniumand bacteria. However, a holistic understanding of the total microbiome has been hindered by a lack of analyses bridging taxonomically disparate groups. Using high-throughput amplicon sequencing, we simultaneously characterized theSymbiodinium, bacterial, and fungal communities associated with the Caribbean coralSiderastrea sidereacollected from two depths (17 and 27 m) on Conch reef in the Florida Keys.S. sidereahosted an exceptionally diverseSymbiodiniumcommunity, structured differently between sampled depth habitats. While dominated at 27 m by aSymbiodiniumbelonging to clade C, at 17 mS. sidereaprimarily hosted a mixture of clade B types. Most fungal operational taxonomic units were distantly related to available reference sequences, indicating the presence of a high degree of fungal novelty within theS. sidereaholobiont and a lack of knowledge on the diversity of fungi on coral reefs. Network analysis showed that co-occurrence patterns in theS. sidereaholobiont were prevalent among bacteria, however, also detected between fungi and bacteria. Overall, our data show a drastic shift in the associatedSymbiodiniumcommunity between depths on Conch Reef, which might indicate that alteration in this community is an important mechanism facilitating local physiological adaptation of theS. sidereaholobiont. In contrast, bacterial and fungal communities were not structured differently between depth habitats.

scholarly journals Assessing biotic and abiotic interactions of micro-organisms in Amazonia through co-occurrence networks and DNA metabarcoding

2021 ◽  
Author(s):  
Camila DUARTE Duarte Ritter ◽  
Dominik Forster ◽  
Josue A. R. Azevedo ◽  
Alexandre Antonelli ◽  
R. Henrik Nilsson ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
High Turnover ◽  
Saprotrophic Fungi ◽  
White Sand ◽  
Network Analyses ◽  
Dna Metabarcoding ◽  
Mineral Soils ◽  
Seasonally Flooded ◽  
Micro Organisms ◽  
Abiotic Interactions

Abstract Species may co-occur due to responses to similar environmental conditions, biological associations, or simply because of coincident geographical distributions. Disentangling patterns of co-occurrence and potential biotic and abiotic interactions is crucial to understand ecosystem function. Here we used DNA metabarcoding data from litter and mineral soils collected from a longitudinal transect in Amazonia to explore patterns of co-occurrence. We compared data from different Amazonian habitat types, each with a characteristic biota and environmental conditions. These included non-flooded rainforests (terra-firme), forests seasonally flooded by fertile white waters (várzeas) or by unfertile black waters (igapós), and open areas associated with white sand soil (campinas). We ran co-occurrence network analyses based on null models and Spearman correlation for all samples and for each habitat separately. We found that one third of all operational taxonomic units (OTUs) were bacteria and two thirds were eukaryotes. The resulting networks were nevertheless mostly composed of bacteria, with fewer fungi, protists, and metazoans. Considering the functional traits of the OTUs, there is a combination of metabolism modes including respiration and fermentation for bacteria, and a high frequency of saprotrophic fungi (those that feed on dead organic matter), indicating a high turnover of organic material. The organic carbon and base saturation indices were important in the co-occurrences in Amazonian networks, whereas several other soil properties were important for the co-exclusion. Different habitats had similar network properties with some variation in terms of modularity, probably associated with flooding pulse. We show that Amazonian micro-organism communities form highly interconnected co-occurrence and co-exclusion networks, which highlights the importance of complex biotic and abiotic interactions in explaining the outstanding biodiversity of the region.

scholarly journals Genetic diversity and phylogenetic analyses of 11 cohorts of captive rhesus macaques from Chinese zoos

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6957
Author(s):  
Qian Su ◽  
Yongfang Yao ◽  
Qin Zhao ◽  
Diyan Li ◽  
Meng Xie ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rhesus Macaques ◽  
Phylogenetic Analyses ◽  
Genetic Management ◽  
Southeastern China ◽  
Mitochondrial Dna Control Region ◽  
Clade B ◽  
In Captivity ◽  
High Level ◽  
Major Haplogroups

Rhesus macaques are raised in almost every Chinese zoo due to their likeability and ease in feeding; however, little is yet known about the genetic diversity of rhesus macaques in captivity. In this study, a 475-base pair nucleotide sequence of the mitochondrial DNA control region was obtained from the fecal DNA of 210 rhesus macaque individuals in captivity. A total of 69 haplotypes were defined, 51 of which (73.9%) were newly identified. Of all haplotypes, seven were shared between two zoos, and 62 haplotypes (89.8%) appeared only in a specific zoo, indicating a low rate of animal exchange between Chinese zoos. Moreover, there was a relatively high level of genetic diversity among the rhesus macaques (Hd = 0.0623 ± 0.0009, Pi = 0.979 ± 0.003, K = 28.974). Phylogenetic analysis demonstrated that all haplotypes were clearly clustered into two major haplogroups—Clade A (southeastern China) and Clade B (southwestern China)—and each major clade contained several small sub-haplogroups. The haplotypes of rhesus macaques from the same zoo were not clustered together for the most part, but scattered among several subclades on the phylogenetic tree. This indicates that the rhesus macaques in most Chinese zoos may originat from a diverse collection of geographical areas. Our results demonstrate that zoos play an important role in the conservation of the genetic diversity of rhesus macaques, as well as provide useful information on the genetic management of captive rhesus macaques.

scholarly journals Long-term fungus-plant co-variation from multi-site sedimentary ancient DNA metabarcoding in Siberia

2021 ◽  
Author(s):  
Barbara von Hippel ◽  
Kathleen R. Stoof-Leichsenring ◽  
Luise Schulte ◽  
Peter Seeber ◽  
Laura S. Epp ◽  
...  
Keyword(s):  
Ancient Dna ◽  
Boreal Forests ◽  
Mycorrhizal Fungus ◽  
Terrestrial Ecosystems ◽  
Dry Forest ◽  
Operational Taxonomic Units ◽  
Arctic Regions ◽  
Southern Tundra ◽  
Dna Metabarcoding

Climate change has a major impact on arctic and boreal terrestrial ecosystems as warming leads to northward treeline shifts, inducing consequences for heterotrophic organisms associated with the plant taxa. To unravel ecological dependencies, we address how long-term climatic changes have shaped the palaeo-ecosystems at selected sites in Siberia. We investigated sedimentary ancient DNA from five lakes spanning the last 47,000 years, using the ITS1 marker for fungi and the chloroplast P6 loop marker for vegetation metabarcoding. After bioinformatic processing with the OBItools pipeline, we obtained 706 unique fungal operational taxonomic units (OTUs) and 243 amplicon sequence variants (ASVs) for the plants. We show higher OTU numbers in dry forest tundra as well as boreal forests compared to wet southern tundra. The most abundant fungal taxa in our dataset are Pseudeurotiaceae, Mortierella, Sordariomyceta, Exophiala, Oidiodendron, Protoventuria, Candida vartiovaarae, Pseudeurotium, Gryganskiella fimbricystis, and Trichosporiella cerebriformis. The overall fungal composition is explained by the plant composition as revealed by redundancy analysis. The fungal functional groups show antagonistic relationships in their climate susceptibility. The advance of woody taxa in response to past warming led to an increase in the abundance of mycorrhizae, lichens, and parasites, while yeast and saprotroph distribution declined. We also show co-occurrences between Salicaceae, Larix, and Alnus and their associated pathogens and detect higher mycorrhizal fungus diversity with the presence of Pinaceae. Under future warming, we can expect feedback between fungus compositional and plant diversity changes which will affect forest advance and stability in arctic regions.

scholarly journals Using pollen DNA metabarcoding to profile nectar sources of urban beekeeping in Kōtō-ku, Tokyo

2020 ◽  
Author(s):  
Keiske Tanaka ◽  
Akinobu Nozaki ◽  
Hazuki Nakadai ◽  
Yuh Shiwa ◽  
Mariko Shimizu-Kadota
Keyword(s):  
Apis Mellifera ◽  
Sampling Strategy ◽  
Species Level ◽  
Urban Greening ◽  
Operational Taxonomic Units ◽  
Ecosystem Protection ◽  
The Family ◽  
Dna Metabarcoding ◽  
The World ◽  
Nectar Sources

Abstract ObjectiveApis mellifera is a species of honeybee that has been introduced around the world as an industrial beekeeping species. Recently, urban beekeeping has attracted attention as a means of ecosystem protection and urban greening. This study aimed to investigate nectar sources of urban beekeeping in Kōtō-ku, Tokyo using pollen DNA metabarcoding.ResultsWe extracted DNA from pollen collected by the honeybees of a local urban beekeeping operation. DNA metabarcoding analysis was carried out by sequencing a part of the rbcL region of the chloroplast genome. A total of 31 samples collected between mid-March, 2018 and mid-October, 2018 yielded 54 operational taxonomic units (OTUs) comprising 14 families, 32 genera, and 8 species. Whereas 5 OTUs were profiled throughout all seasons, 38 OTUs were season-specific (spring, summer, or autumn). Therefore, we were able to infer seasonal nectar sources for the beekeeping operation at the family or genus level, as well as at the species level to a lesser extent. Our pollen-sampling strategy was effective for profiling season-specific nectar sources, with the exception of a few anomalies that can be accounted for by out-of-season flowering associated with artificial gardening and/or pollen accumulation over multiple seasons.

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