0433 - Unicellular eukaryotes distance-decay and taxa-area relationships within freshwater mountainous ponds

2018 ◽  
Author(s):  
Chertiona Sofia Macingo ◽  
Konstantinos Kormas
Keyword(s):  
Distance Decay ◽  
Unicellular Eukaryotes

scholarly journals Taxa–area and distance–decay relationships of unicellular eukaryotes along an elevation gradient of mountainous freshwater ecosystems

2019 ◽  
Vol 41 (6) ◽  
pp. 821-834
Author(s):  
Sofia C Macingo ◽  
Konstantinos A Kormas ◽  
Andreas Oikonomou ◽  
Hera Karayanni
Keyword(s):  
High Throughput Sequencing ◽  
Gene Diversity ◽  
Elevation Gradient ◽  
Environmental Filtering ◽  
18S Rrna Gene ◽  
Freshwater Ecosystems ◽  
Distance Decay ◽  
Unicellular Eukaryote ◽  
Rrna Gene ◽  
Unicellular Eukaryotes

Abstract Unicellular eukaryotes have pivotal ecological roles in aquatic ecosystems by participating in biogeochemical processes and structuring microbial food webs. However, revealing their biogeographical patterns remains challenging, as it is reflected in the rather limited available knowledge. In this study, two central patterns, the taxa–area and the distance–decay relationships, were tested for freshwater unicellular eukaryotes. Sampling was performed in 31 mountainous freshwater ecosystems in Thessaly (Greece). Sampling sites had different geohydromorphological characteristics (altitude, 124–704 m; depth, 0.3–1 m; surface area, 188–123 000 m2; geographical distances, 0.03–48.4 km). Unicellular eukaryote diversity was assessed by 18S rRNA gene diversity with high-throughput sequencing. Five supergroups (Stramenopiles, Alveolata, Rhizaria, Archaeplastida and Opisthokonta) were found with the most abundant taxa being Stramenopiles and Alveolata. Aquatic unicellular eukaryotes showed statistically significant but weak DDR and TAR. This can be attributed to the large proportion of specialists (91.9% of operational taxonomic units according to Levin’s index). These results indicate that although mountainous pools and ponds can host high diversity of unicellular eukaryotes, the shaping of their communities is mainly regulated by niche-specific processes and environmental filtering and to a lesser extent by species dispersion processes.

scholarly journals Comparative genomics reveals new functional insights in uncultured MAST species

2021 ◽  
Author(s):  
Aurelie Labarre ◽  
David López-Escardó ◽  
Francisco Latorre ◽  
Guy Leonard ◽  
François Bucchini ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Genomic Data ◽  
Proton Pumps ◽  
Functional Annotations ◽  
The Core ◽  
Unicellular Eukaryotes ◽  
Microbial Eukaryotes ◽  
Core Energy ◽  
Marine Surface ◽  
Environmental Sequences

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.

scholarly journals High and specific diversity of protists in the deep-sea basins dominated by diplonemids, kinetoplastids, ciliates and foraminiferans

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alexandra Schoenle ◽  
Manon Hohlfeld ◽  
Karoline Hermanns ◽  
Frédéric Mahé ◽  
Colomban de Vargas ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Deep Sea ◽  
Trophic Levels ◽  
Earth System ◽  
Parasitic Species ◽  
Unicellular Eukaryotes ◽  
The Earth ◽  
Dna Metabarcoding ◽  
Global Carbon ◽  
Pelagic Communities

AbstractHeterotrophic protists (unicellular eukaryotes) form a major link from bacteria and algae to higher trophic levels in the sunlit ocean. Their role on the deep seafloor, however, is only fragmentarily understood, despite their potential key function for global carbon cycling. Using the approach of combined DNA metabarcoding and cultivation-based surveys of 11 deep-sea regions, we show that protist communities, mostly overlooked in current deep-sea foodweb models, are highly specific, locally diverse and have little overlap to pelagic communities. Besides traditionally considered foraminiferans, tiny protists including diplonemids, kinetoplastids and ciliates were genetically highly diverse considerably exceeding the diversity of metazoans. Deep-sea protists, including many parasitic species, represent thus one of the most diverse biodiversity compartments of the Earth system, forming an essential link to metazoans.

scholarly journals The Autophagy Machinery in Human-Parasitic Protists; Diverse Functions for Universally Conserved Proteins

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1258
Author(s):  
Hirokazu Sakamoto ◽  
Kumiko Nakada-Tsukui ◽  
Sébastien Besteiro
Keyword(s):  
Membrane Vesicle ◽  
Model Organisms ◽  
Unicellular Eukaryotes ◽  
Current State ◽  
Important Challenge ◽  
Molecular Machinery ◽  
Cellular Machinery ◽  
Apparent Reduction ◽  
Related Proteins ◽  
Genome Projects

Autophagy is a eukaryotic cellular machinery that is able to degrade large intracellular components, including organelles, and plays a pivotal role in cellular homeostasis. Target materials are enclosed by a double membrane vesicle called autophagosome, whose formation is coordinated by autophagy-related proteins (ATGs). Studies of yeast and Metazoa have identified approximately 40 ATGs. Genome projects for unicellular eukaryotes revealed that some ATGs are conserved in all eukaryotic supergroups but others have arisen or were lost during evolution in some specific lineages. In spite of an apparent reduction in the ATG molecular machinery found in parasitic protists, it has become clear that ATGs play an important role in stage differentiation or organelle maintenance, sometimes with an original function that is unrelated to canonical degradative autophagy. In this review, we aim to briefly summarize the current state of knowledge in parasitic protists, in the light of the latest important findings from more canonical model organisms. Determining the roles of ATGs and the diversity of their functions in various lineages is an important challenge for understanding the evolutionary background of autophagy.

Concentrated and Close to Home: The Spatial Clustering and Distance Decay of Lone Terrorist Vehicular Attacks

2019 ◽  
Vol 36 (3) ◽  
pp. 607-645 ◽  
Author(s):  
Badi Hasisi ◽  
Simon Perry ◽  
Yonatan Ilan ◽  
Michael Wolfowicz
Keyword(s):  
Spatial Clustering ◽  
Distance Decay

scholarly journals Distance decay in delivery care utilisation associated with neonatal mortality. A case referent study in northern Vietnam

2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Mats Målqvist ◽  
Nazmul Sohel ◽  
Tran T Do ◽  
Leif Eriksson ◽  
Lars-Åke Persson
Keyword(s):  
Neonatal Mortality ◽  
Distance Decay ◽  
Delivery Care ◽  
Northern Vietnam ◽  
Care Utilisation
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