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https://www.readbyqxmd.com/read/28338675/biogeography-and-diversity-of-collodaria-radiolaria-in-the-global-ocean
#1
Tristan Biard, Estelle Bigeard, Stéphane Audic, Julie Poulain, Andres Gutierrez-Rodriguez, Stéphane Pesant, Lars Stemmann, Fabrice Not
Collodaria are heterotrophic marine protists that exist either as large colonies composed of hundreds of cells or as large solitary cells. All described species so far harbour intracellular microalgae as photosymbionts. Although recent environmental diversity surveys based on molecular methods demonstrated their consistently high contribution to planktonic communities and their worldwide occurrence, our understanding of their diversity and biogeography is still very limited. Here we estimated the 18S ribosomal DNA (rDNA) gene copies per collodarian cell for solitary (5770±1960 small subunit (SSU) rDNA copies) and colonial specimens (37 474±17 799 SSU rDNA copies, for each individual cell within a colony) using single-specimen quantitative PCR...
March 24, 2017: ISME Journal
https://www.readbyqxmd.com/read/28334205/tetrahymena-phagocytic-vesicles-as-ecological-micro-niches-of-phage-transfer
#2
Iqbal Aijaz, Gerald B Koudelka
The microbial communities in natural environments such as soil, pond water, or animal rumens are comprised of a diverse mixture of bacteria and protozoa including ciliates or flagellates. In such microbiomes, a major source of bacterial mortality is grazing by phagocytic protists. Many protists are omnivorous heterotrophs, feeding on a range of different bacterial species. Due to this indiscriminate feeding, different bacterial species can assemble together in the same phagocytic vesicles where can they potentially exchange genetic material...
March 3, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/28334157/overview-of-freshwater-microbial-eukaryotes-diversity-a-first-analysis-of-publicly-available-metabarcoding-data
#3
Didier Debroas, Isabelle Domaizon, Jean-Francois Humbert, Ludwig Jardillier, Cécile Lepère, Anne Oudart, Najwa Taïb
Although they are widespread, diverse, and involved in biogeochemical cycles, microbial eukaryotes attract less attention than their prokaryotic counterparts in environmental microbiology. In this study, we used publicly available 18S barcoding data to define biases that may limit such analyses and to gain an overview of the planktonic microbial eukaryotic diversity in freshwater ecosystems. The richness of the microbial eukaryotes was estimated to 100,798 operational taxonomic units (OTUs) delineating 1267 clusters or phylogenetic units (PUs i...
March 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/28333264/single-cell-transcriptomics-mega-phylogeny-and-the-genetic-basis-of-morphological-innovations-in-rhizaria
#4
Anders K Krabberød, Russell J S Orr, Jon Bråte, Tom Kristensen, Kjell R Bjørklund, Kamran Shalchian-Tabrizi
The innovation of the eukaryote cytoskeleton enabled phagocytosis, intracellular transport and cytokinesis, and is responsible for the diversity of eukaryotic morphologies. Still, the relationship between phenotypic innovations in the cytoskeleton and their underlying genotype is poorly understood. To explore the genetic mechanism of morphological evolution of the eukaryotic cytoskeleton we provide the first single cell transcriptomes from uncultured, free-living unicellular eukaryotes: the polycystine radiolarian Lithomelissa setosa (Nassellaria) and Sticholonche zanclea (Taxopodida)...
March 1, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28324738/protist-evolution-stealing-genes-to-gut-it-out
#5
David Moreira, Purificación López-García
The amount and evolutionary impact of horizontal gene transfer in eukaryotes remain contentious issues. A new phylogenomic study suggests that gene transfer from prokaryotes has contributed significantly to the adaptation and metabolic evolution of Blastocystis, the most widespread human gut eukaryotic parasite.
March 20, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28321010/discovery-and-complete-genome-sequence-of-a-bacteriophage-from-an-obligate-intracellular-symbiont-of-a-cellulolytic-protist-in-the-termite-gut
#6
Ajeng K Pramono, Hirokazu Kuwahara, Takehiko Itoh, Atsushi Toyoda, Akinori Yamada, Yuichi Hongoh
Termites depend nutritionally on their gut microbes, and protistan, bacterial, and archaeal gut communities have been extensively studied. However, limited information is available on viruses in the termite gut. We herein report the complete genome sequence (99,517 bp) of a phage obtained during a genome analysis of "Candidatus Azobacteroides pseudotrichonymphae" phylotype ProJPt-1, which is an obligate intracellular symbiont of the cellulolytic protist Pseudotrichonympha sp. in the gut of the termite Prorhinotermes japonicus...
March 17, 2017: Microbes and Environments
https://www.readbyqxmd.com/read/28318115/microbial-players-and-processes-involved-in-phytoplankton-bloom-utilization-in-the-water-column-of-a-fast-flowing-river-dominated-estuary
#7
Maria W Smith, Lydie Herfort, Caroline S Fortunato, Byron C Crump, Holly M Simon
Fueled by seasonal phytoplankton blooms, the Columbia River estuary is a natural bioreactor for organic matter transformations. Prior metagenome analyses indicated high abundances of diverse Bacteroidetes taxa in estuarine samples containing phytoplankton. To examine the hypothesis that Bacteroidetes taxa have important roles in phytoplankton turnover, we further analyzed metagenomes from water collected along a salinity gradient at 0, 5, 15, 25, and 33 PSU during bloom events. Size fractions were obtained by using a 3-μm prefilter and 0...
March 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28304358/a-pelagic-microbiome-viruses-to-protists-from-a-small-cup-of-seawater
#8
Flavia Flaviani, Declan C Schroeder, Cecilia Balestreri, Joanna L Schroeder, Karen Moore, Konrad Paszkiewicz, Maya C Pfaff, Edward P Rybicki
The aquatic microbiome is composed of a multi-phylotype community of microbes, ranging from the numerically dominant viruses to the phylogenetically diverse unicellular phytoplankton. They influence key biogeochemical processes and form the base of marine food webs, becoming food for secondary consumers. Due to recent advances in next-generation sequencing, this previously overlooked component of our hydrosphere is starting to reveal its true diversity and biological complexity. We report here that 250 mL of seawater is sufficient to provide a comprehensive description of the microbial diversity in an oceanic environment...
March 17, 2017: Viruses
https://www.readbyqxmd.com/read/28303119/viruses-and-protists-induced-mortality-of-prokaryotes-around-the-antarctic-peninsula-during-the-austral-summer
#9
Dolors Vaqué, Julia A Boras, Francesc Torrent-Llagostera, Susana Agustí, Jesús M Arrieta, Elena Lara, Yaiza M Castillo, Carlos M Duarte, Maria M Sala
During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28299647/runx-in-invertebrates
#10
S Hughes, A Woollard
Runx genes have been identified in all metazoans and considerable conservation of function observed across a wide range of phyla. Thus, insight gained from studying simple model organisms is invaluable in understanding RUNX biology in higher animals. Consequently, this chapter will focus on the Runx genes in the diploblasts, which includes sea anemones and sponges, as well as the lower triploblasts, including the sea urchin, nematode, planaria and insect. Due to the high degree of functional redundancy amongst vertebrate Runx genes, simpler model organisms with a solo Runx gene, like C...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28295310/a-rare-case-of-plastid-protein-coding-gene-duplication-in-the-chloroplast-genome-of-euglena-archaeoplastidiata-euglenophyta
#11
Matthew S Bennett, Shin-Han Shiu, Richard E Triemer
Gene duplication is an important evolutionary process that allows duplicate functions to diverge, or, in some cases, allows for new functional gains. However, in contrast to the nuclear genome, gene duplications within the chloroplast are extremely rare. Here, we present the chloroplast genome of the photosynthetic protist Euglena archaeoplastidiata. Upon annotation it was found that the chloroplast genome contained a novel tandem direct duplication which encoded a portion of RuBisCO large subunit (rbcL) followed by a complete copy of ribosomal protein L32 (rpl32) as well as the associated intergenic sequences...
March 12, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28290059/review-origin-of-complex-algae-by-secondary-endosymbiosis-a-journey-through-time
#12
REVIEW
J Gentil, F Hempel, D Moog, S Zauner, U G Maier
Secondary endosymbiosis-the merging of two eukaryotic cells into one photosynthetic cellular unit-led to the evolution of ecologically and medically very important organisms. We review the biology of these organisms, starting from the first proposal of secondary endosymbiosis up to recent phylogenetic models on the origin of secondarily evolved protists. In addition, we discuss the organelle character of the symbionts based on morphological features, gene transfers from the symbiont into the host and re-import of nucleus-encoded plastid proteins...
March 13, 2017: Protoplasma
https://www.readbyqxmd.com/read/28286224/phylogeny-classification-and-diversity-of-choreotrichia-and-oligotrichia-ciliophora-spirotrichea
#13
Luciana F Santoferrara, Viviana V Alder, George B McManus
Ciliated protists in the subclasses Choreotrichia and Oligotrichia are major components of marine plankton. Despite their ecological relevance, there are uncertainties in their systematics and diversity. We retrieved and curated all the GenBank ribosomal DNA (rDNA) sequences from these groups, which were analyzed in two ways. The first approach was based on morphologically-identified sequences (including those of two families and six genera newly studied here by single-cell sequencing), and aimed at improving phylogenetic inferences using concatenated sequences of three rDNA loci...
March 9, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28285259/distribution-of-ciliates-in-intertidal-sediments-across-geographic-distances-a-molecular-view
#14
Feng Zhao, Kuidong Xu
The estimation of the diversity and geographic distribution of protists in particular ciliates has long been an ongoing debate. We estimated the distribution of ciliates in intertidal sediments with geographic distance ranging from 10cm to 1,000km, using high-throughput DNA sequencing. Higher community similarity, in particular that of rare ciliate taxa, occurred between replicates than between sites. Statistical analyses showed that the community dissimilarities of both abundant and moderately abundant ciliates had correlations with geographic distance at the scales of 50m, 200km and 1000km, indicating a distance-decay relationship...
January 19, 2017: Protist
https://www.readbyqxmd.com/read/28284996/first-survey-of-cryptosporidium-giardia-and-enterocytozoon-in-diarrhoeic-children-from-wuhan-china
#15
Tao Wang, Yingying Fan, Anson V Koehler, Guangxu Ma, Tao Li, Min Hu, Robin B Gasser
Intestinal protozoan pathogens cause significant diarrhoeal diseases in children. However, to date, there has been limited genetic study of the intestinal pathogens Cryptosporidium, Giardia and Enterocytozoon in humans in China, with the exception of research in a small number of cities/provinces. In the present study, PCR-based tools were used to detect and characterise these protistan parasites from 500 children with a history of diarrhoea in Wuhan and environs, Hubei province, China. Genomic DNAs from faecal samples were screened for the particular protists by PCR utilising regions in the small subunit (SSU) of the nuclear ribosomal RNA, the 60kDa glycoprotein (gp60), the internal transcribed spacer of nuclear ribosomal DNA (ITS) and/or the triose phosphate isomerase (tpi) genes as genetic markers...
March 8, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28283521/an-amoebal-grazer-of-cyanobacteria-requires-cobalamin-produced-by-heterotrophic-bacteria
#16
Amy T Ma, Joris Beld, Bianca Brahamsha
Amoebae are unicellular eukaryotes that consume microbial prey through phagocytosis, playing a role in shaping microbial foodwebs. Many amoebal species can be cultivated axenically in rich media or monoxenically with single bacterial prey species. Here we characterize heterolobosean amoeba LPG3, a recent natural isolate, which is unable to grow on unicellular cyanobacteria, its primary food source, in the absence of a heterotrophic bacterium, a Pseudomonas species coisolate. To investigate the molecular basis of this requirement for heterotrophic bacteria, we performed a screen using a defined non-redundant transposon library of Vibrio cholerae which implicated genes in corrinoid uptake and biosynthesis...
March 10, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28283352/the-s-c-ensory-immune-system-theory
#17
REVIEW
Henrique Veiga-Fernandes, António A Freitas
Viewpoints on the immune system have evolved across different paradigms, including the clonal selection theory, the idiotypic network, and the danger and tolerance models. Herein, we propose that in multicellular organisms, where panoplies of cells from different germ layers interact and immune cells are constantly generated, the behavior of the immune system is defined by the rules governing cell survival, systems physiology and organismic homeostasis. Initially, these rules were imprinted at the single cell-protist level, but supervened modifications in the transition to multicellular organisms...
March 7, 2017: Trends in Immunology
https://www.readbyqxmd.com/read/28273342/robust-dinoflagellata-phylogeny-inferred-from-public-transcriptome-databases
#18
Dana C Price, Debashish Bhattacharya
Dinoflagellates are dominant members of the plankton and play key roles in ocean ecosystems as primary producers, predators, parasites, coral photobionts, and causative agents of algal blooms that produce toxins harmful to humans and commercial fisheries. These unicellular protists exhibit remarkable trophic and morphological diversity and include species with some of the largest reported nuclear genomes. Despite their high ecological and economic importance, comprehensive genome (or transcriptome) based dinoflagellate trees of life are few in number...
March 8, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28265986/manipulation-of-auxin-and-cytokinin-balance-during-the-plasmodiophora-brassicae-arabidopsis-thaliana-interaction
#19
Jutta Ludwig-Müller, Susann Auer, Sabine Jülke, Sabine Marschollek
The symptoms of the clubroot disease on Brassica species caused by the obligate biotrophic protist Plasmodiophora brassicae relies, among other factors, on the modulation of plant hormones. Signaling, transport as well as biosynthesis and metabolism are key features how the levels of auxins and cytokinins are controlled. We here describe (a) how to inoculate the model plant Arabidopsis thaliana with P. brassicae, (b) qualitative and quantitative methods to evaluate disease severity in auxin and cytokinin mutants,...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28265694/microbial-communities-as-environmental-indicators-of-ecological-disturbance-in-restored-carbonate-fen-results-of-10%C3%A2-years-of-studies
#20
Tomasz Mieczan, Monika Tarkowska-Kukuryk
Interactions between bacteria and protists are essential to the ecosystem ecology of fens. Until now, however, there has been almost no information on how restoration procedures in carbonate fens affect the functioning of microbial food webs. Changes in vegetation patterns resulting from restoration may take years to be observed, whereas microbial processes display effects even after short-term exposure to changes in environmental conditions caused by restoration. Therefore, microbial processes and patterns can be used as sensitive indicators of changes in environmental conditions...
March 6, 2017: Microbial Ecology
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