scholarly journals Inventory of the benthic eukaryotic diversity in the oldest European lake

2021 ◽  
Author(s):  
Benjamin Wilden ◽  
Walter Traunspurger ◽  
Stefan Geisen
Keyword(s):  
Eukaryotic Diversity

Total organic carbon and the preservation of organic-walled microfossils in Precambrian shale

Geology ◽  
2020 ◽  
Author(s):  
C.R. Woltz ◽  
S.M. Porter ◽  
H. Agić ◽  
C.M. Dehler ◽  
C.K. Junium ◽  
...  
Keyword(s):  
Species Richness ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Microbial Degradation ◽  
Sedimentation Rate ◽  
Surface Pattern ◽  
Causal Factors ◽  
Eukaryotic Diversity ◽  
High Concentrations ◽  
Fossil Preservation

Much of our understanding of early eukaryote diversity and paleoecology comes from the record of organic-walled microfossils in shale, yet the conditions controlling their preservation are not well understood. It has been suggested that high concentrations of total organic carbon (TOC) inhibit the preservation of organic fossils in shale, and although this idea is supported anecdotally, it has never been tested. Here we compared the presence, preservational quality, and assemblage diversity of organic-walled microfossils to TOC concentrations of 346 shale samples that span the late Paleoproterozoic to middle Neoproterozoic in age. We found that fossil-bearing samples have significantly lower median TOC values (0.32 wt%, n = 189) than those containing no fossils (0.72 wt%, n = 157). Preservational quality, measured by the loss of surface pattern, density of pitting, and deterioration of wall margin, decreases as TOC increases. Species richness negatively correlates with TOC within the ca. 750 Ma Chuar Group (Arizona, USA), but no relationship is observed in other units. These results support the hypothesis that high TOC content either decreases the preservational quality or inhibits the preservation of organic-walled microfossils altogether. However, it is also possible that other causal factors, including sedimentation rate and microbial degradation, account for the correlation between fossil preservation and TOC. We expect that as TOC varies in space and time, so too does the probability of finding well-preserved fossils. A compilation of 13,940 TOC values spanning Earth history suggests significantly higher median TOC levels in Mesoproterozoic versus Neoproterozoic shale, potentially biasing the interpreted pattern of increased eukaryotic diversity in the Tonian.

Comparing High-throughput Platforms for Sequencing the V4 Region of SSU-rDNA in Environmental Microbial Eukaryotic Diversity Surveys

2014 ◽  
Vol 62 (3) ◽  
pp. 338-345 ◽  
Author(s):  
Frédéric Mahé ◽  
Jordan Mayor ◽  
John Bunge ◽  
Jingyun Chi ◽  
Tobias Siemensmeyer ◽  
...  
Keyword(s):  
High Throughput ◽  
Ssu Rdna ◽  
Eukaryotic Diversity

scholarly journals Bacterial, Archaeal, and Eukaryotic Diversity across Distinct Microhabitats in an Acid Mine Drainage

2017 ◽  
Vol 8 ◽  
Author(s):  
Victoria Mesa ◽  
Jose L. R. Gallego ◽  
Ricardo González-Gil ◽  
Béatrice Lauga ◽  
Jesús Sánchez ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Eukaryotic Diversity ◽  
Acid Mine

The Protists in Soil—A Token of Untold Eukaryotic Diversity

2019 ◽  
pp. 125-140 ◽  
Author(s):  
Michael Bonkowski ◽  
Kenneth Dumack ◽  
Anna Maria Fiore-Donno
Keyword(s):  
Eukaryotic Diversity

scholarly journals A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites

2018 ◽  
Author(s):  
Yong Tang ◽  
Thomas R. Meister ◽  
Marta Walczak ◽  
Michael J. Pulkoski-Gross ◽  
Sanjay B. Hari ◽  
...  
Keyword(s):  
Drug Targets ◽  
Metabolic Enzyme ◽  
Parasitic Diseases ◽  
Organelle Biogenesis ◽  
Cellular Functions ◽  
Fluorescent Reporter ◽  
Forward Genetic Screen ◽  
Mutagenesis Screen ◽  
Eukaryotic Diversity ◽  
Tim Barrel

SummaryEndosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid, the apicoplast, which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in P. falciparum. Apicoplast-minus mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a TIM-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly-identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.

scholarly journals Long-chain diols in rivers: distribution and potential biological sources

2018 ◽  
Author(s):  
Julie Lattaud ◽  
Frédérique Kirkels ◽  
Francien Peterse ◽  
Chantal V. Freymond ◽  
Timothy I. Eglinton ◽  
...  
Keyword(s):  
River Flow ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
River Systems ◽  
Eukaryotic Diversity ◽  
Suspended Particulate ◽  
Fractional Abundance ◽  
Biological Sources ◽  
Rrna Gene Sequencing ◽  
Long Chain

Abstract. Long chain diols (LCDs) occur widespread in marine environments and also in lakes and rivers. Transport of LCDs from rivers may impact the distribution of LCDs in coastal environments, however relatively little is known about the distribution and biological sources of LCDs in river systems. In this study, we investigated the distribution of LCDs in suspended particulate matter (SPM) of three river systems (Godavari, Danube, and Rhine) in relation with season, precipitation, temperature, and source catchments. The dominant long-chain diol is the C32 1,15-diol followed by the C30 1,15-diol in all studied river systems. In regions influenced by marine waters, such as delta systems, the fractional abundance of the C30 1,15-diol is substantially higher than in the river itself, suggesting different LCD producers in marine and freshwater environments. A change in the LCD distribution along the downstream transects of the rivers studied was not observed. However, an effect of river flow is observed, i.e. the concentration of the C32 1,15-diol is higher in stagnant waters, such as reservoirs and during seasons with river low stands. A seasonal change in the LCD distribution was observed in the Rhine, likely due to a change in the producers. Eukaryotic diversity analysis by 18S rRNA gene sequencing of SPM from the Rhine showed extremely low abundances of sequences (i.e.

Novel syntaxin gene sequences from Giardia, Trypanosoma and algae: implications for the ancient evolution of the eukaryotic endomembrane system

2002 ◽  
Vol 115 (8) ◽  
pp. 1635-1642 ◽  
Author(s):  
Joel B. Dacks ◽  
W. Ford Doolittle
Keyword(s):  
Protein Interactions ◽  
Calcium Binding ◽  
Parallel Evolution ◽  
Membrane System ◽  
Compartment System ◽  
Eukaryotic Diversity ◽  
Wide Range ◽  
Membrane Compartment ◽  
Isoleucine Residue

SNAP receptors or SNARES are crucial components of the intracellular membrane system of eukaryotes. The syntaxin family of SNAREs have been shown to have roles in neurotransmission, vesicular transport, membrane fusion and even internal membrane compartment reconstruction. While syntaxins and SNAREs in general have been well characterized in mammalian and yeast models, little is known about their overall distribution across eukaryotic diversity or about the evolution of the syntaxin gene family. By combining bioinformatic,molecular biological and phylogenetic approaches, we demonstrate that various syntaxin homologs are not only present in `eukaryotic crown taxa' but across a wide range of eukaryotic lineages. The alignment of evolutionarily diverse syntaxin paralogs shows that an isoleucine residue critical to nSec1—syntaxin complex formation and the characteristic syntaxin glutamine residue are nearly universally conserved, implying a general functional importance for these residues. Other identified functional residues involved in botulism toxicity and calcium-binding-protein interactions are also compared. The presence of Golgi-related syntaxins in the intestinal parasite Giardia intestinalis provides further evidence for a cryptic Golgi in this `adictyosomal' taxon, and another likely case of secondary reduction in this parasite. The phylogeny of syntaxins shows a number of nested duplications, including a case of parallel evolution in the plasma membrane-associated syntaxins, and ancestral duplications in the other syntaxin paralogs. These speak to ancient events in the evolution of the syntaxin system and emphasize the universal role of the syntaxins in the eukaryotic intracellular compartment system.

scholarly journals Evolution of Mutator transposable elements across eukaryotic diversity

Mobile DNA ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mathilde Dupeyron ◽  
Kumar S. Singh ◽  
Chris Bass ◽  
Alexander Hayward
Keyword(s):  
Transposable Elements ◽  
Eukaryotic Diversity

scholarly journals Endosymbiosis undone by stepwise elimination of the plastid in a parasitic dinoflagellate

2015 ◽  
Vol 112 (18) ◽  
pp. 5767-5772 ◽  
Author(s):  
Sebastian G. Gornik ◽  
Febrimarsa ◽  
Andrew M. Cassin ◽  
James I. MacRae ◽  
Abhinay Ramaprasad ◽  
...  
Keyword(s):  
Rare Case ◽  
Genomic Sequencing ◽  
Sequencing Data ◽  
Apicomplexan Parasites ◽  
Eukaryotic Diversity ◽  
Metabolic Functions ◽  
A Cell ◽  
Endosymbiotic Organelle ◽  
Marine Parasite

Organelle gain through endosymbiosis has been integral to the origin and diversification of eukaryotes, and, once gained, plastids and mitochondria seem seldom lost. Indeed, discovery of nonphotosynthetic plastids in many eukaryotes—notably, the apicoplast in apicomplexan parasites such as the malaria pathogen Plasmodium—highlights the essential metabolic functions performed by plastids beyond photosynthesis. Once a cell becomes reliant on these ancillary functions, organelle dependence is apparently difficult to overcome. Previous examples of endosymbiotic organelle loss (either mitochondria or plastids), which have been invoked to explain the origin of eukaryotic diversity, have subsequently been recognized as organelle reduction to cryptic forms, such as mitosomes and apicoplasts. Integration of these ancient symbionts with their hosts has been too well developed to reverse. Here, we provide evidence that the dinoflagellate Hematodinium sp., a marine parasite of crustaceans, represents a rare case of endosymbiotic organelle loss by the elimination of the plastid. Extensive RNA and genomic sequencing data provide no evidence for a plastid organelle, but, rather, reveal a metabolic decoupling from known plastid functions that typically impede organelle loss. This independence has been achieved through retention of ancestral anabolic pathways, enzyme relocation from the plastid to the cytosol, and metabolic scavenging from the parasite’s host. Hematodinium sp. thus represents a further dimension of endosymbiosis—life after the organelle.

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