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Ana Carolina Loyola-Machado, Allan Cézar Azevedo-Martins, Carolina Moura Costa Catta-Preta, Wanderley de Souza, Antonio Galina, Maria Cristina M Motta
The mutualistic relationship between trypanosomatids and their respective endosymbiotic bacteria represents an excellent model for studying metabolic co-evolution since the symbiont completes essential biosynthetic routes of the host cell. In this work, we investigated the influence of the endosymbiont on the energy metabolism of Strigomonas culicis by comparing the wild strain with aposymbiotic protists. The bacterium maintains a frequent and close association with glycosomes, which are distributed around the prokaryote...
February 28, 2017: Protist
Duckhyun Lhee, Eun Chan Yang, Jong Im Kim, Takuro Nakayama, Giuseppe Zuccarello, Robert A Andersen, Hwan Su Yoon
The thecate filose amoeba Paulinella chromatophora is a good model organism for understanding plastid organellogenesis because its chromatophore was newly derived from an alpha-cyanobacterium. Paulinella chromatophora was the only known photosynthetic Paulinella species until recent studies that suggested a species level of diversity. Here, we described a new photosynthetic species P. micropora sp. nov. based on morphological and molecular evidence from a newly established strain KR01. The chromatophore genome of P...
February 14, 2017: Protist
Nicolaus G Adams, Piper Schwenke, G Jason Smith, Vera L Trainer
Microsatellites are commonly used markers in population genetics and are increasingly being employed to determine population structure in phytoplankton populations. We have developed seven polymorphic microsatellite markers for the domoic-acid producing diatom Pseudo-nitzschia australis. Using these markers, thirty P. australis isolates were genotyped, 10 isolates were from Monterey Bay, California and 20 were from off the northern coast of Oregon. The number of alleles per locus ranged from two to eight and observed heterozygosities ranged from 0...
January 26, 2017: Protist
Aubrey Davis, Raffaela Abbriano, Sarah R Smith, Mark Hildebrand
Evidence suggests that diatom photorespiratory metabolism is distinct from other photosynthetic eukaryotes in that there may be at least two routes for the metabolism of the photorespiratory metabolite glycolate. One occurs primarily in the mitochondria and is similar to the C2 photorespiratory pathway, and the other processes glycolate through the peroxisomal glyoxylate cycle. Genomic analysis has identified the presence of key genes required for glycolate oxidation, the glyoxylate cycle, and malate metabolism, however, predictions of intracellular localization can be ambiguous and require verification...
February 2017: Protist
Sebastian Hess
The genus Hyalodiscus Hertwig and Lesser, 1874 comprises naked freshwater amoebae with a unique set of characters, namely a vibrant orange-red colour, a discoid or fan-shaped morphology, and a characteristic rolling locomotion. Some species feed on the chloroplasts of green algae and were regarded as relatives of Vampyrella Cienkowski, 1865. However, because of striking morphological differences and the lack of molecular data, the exact relationship of Hyalodiscus to vampyrellids is still obscure. Here, I describe Hyalodiscus flabellus sp...
February 2017: Protist
Zoltán Füssy, Petra Masařová, Jitka Kručinská, Heather J Esson, Miroslav Oborník
Ease of cultivation and availability of genomic data promoted intensive research of free-living phototrophic relatives of apicomplexans, i.e. Chromera velia and Vitrella brassicaformis. Chromera and Vitrella differ significantly in their physiology, morphology, phylogenetic position and genomic features, but Vitrella has not gained as much attention. Here we describe two types of Vitrella zoosporangia. One contains zoospores surrounded by roughly structured matter, with an intracytoplasmic axoneme predicted to develop into a mature flagellum upon spore release, similarly to Plasmodium microgametes; in the second type, cells concurrently bud off the center of the sporangium, surrounded by smooth matter, and flagella develop extracellularly...
February 2017: Protist
Kenneth Dumack, Hüsna Öztoprak, Lioba Rüger, Michael Bonkowski
For over a century testate amoebae have been a favoured group of interest for protistologists, however there is still an endless amount of unanswered questions. The genus Plagiophrys, Claparède and Lachmann 1859, is still one of the unresolved mysteries as it comprises species with high morphological diversity of which no molecular data are available. To shed light on the phylogeny and taxonomy of Plagiophrys we (a) cultured four isolates of three Plagiophrys morphospecies and provided morphological observations (b) obtained three new SSU RNA gene sequences and conducted phylogenetic analyses of the Thecofilosea and (c) did intensive literature research, showing that Plagiophrys is polyphyletic...
February 2017: Protist
Emily A Seward, Jan Votýpka, Petr Kment, Julius Lukeš, Steven Kelly
Phytomonas spp. (phytomonads) are a diverse and globally distributed group of unicellular eukaryotes that parasitize a wide range of plants and are transmitted by insect hosts. Here we report the discovery and characterisation of a new species of Phytomonas, named Phytomonas oxycareni n. sp., which was obtained from the salivary glands of the invasive species of true bug Oxycarenus lavaterae (Heteroptera). The new Phytomonas species exhibits a long slender promastigote morphology and can be found both within the lumen of the insect host's salivary glands as well as within the cells of the salivary gland itself...
February 2017: Protist
Matt P Ashworth, Christopher S Lobban, Andrzej Witkowski, Edward C Theriot, Meeshal J Sabir, Mohammad N Baeshen, Nahid H Hajarah, Nabih A Baeshen, Jamal S Sabir, Robert K Jansen
Several lineages of raphe-bearing diatoms possess a "stauros," which is a transverse, usually thickened area free of pores across the center of the valve. It has been suggested that this structure has evolved several times across the raphid diatoms, but we have noticed similarities beyond the stauros between two marine genera-Craspedostauros and Staurotropis-in the structure of their pore occlusions. We have isolated, cultured and extracted DNA from several strains of both genera to infer the phylogenetic relationship between these taxa, as well as test the suggested relationship of Craspedostauros to Achnanthes and Mastogloia based on plastid morphology...
February 2017: Protist
Kelsey A Ellis, Natalie R Cohen, Carly Moreno, Adrian Marchetti
The requirement for cobalamin (vitamin B12) in microalgae is primarily a function of the type of methionine synthase present within their gene repertoires. Our study validates this concept through analysis of the distribution of B12-independent methionine synthase in ecologically relevant diatom genera, including the closely related bloom-forming genera Pseudo-nitzschia and Fragilariopsis. Growth and gene expression analysis of the vitamin B12-requiring version of the methionine synthase enzyme, METH, and the B12-independent version, METE, demonstrate that it is the presence of the METE gene which allows Fragilariopsis cylindrus to grow in the absence of B12...
February 2017: Protist
Anna Busch, Sebastian Hess
Several distantly related, phagotrophic microeukaryotes share the remarkable ability to perforate foreign cell walls in a well-defined pattern to acquire protoplast material as food. The underlying cellular processes, especially the local application of cell wall degrading agents, are still unexplored. We examined the distribution of F-actin and alpha-tubulin in the algivorous, viridiraptorid amoeboflagellates Orciraptor agilis and Viridiraptor invadens over their life histories using phalloidin conjugates and immunolocalization...
February 2017: Protist
Shuwen Zhang, Kit Yu Karen Chan, Zhuo Shen, Shunyan Cheung, Michael R Landry, Hongbin Liu
The dinoflagellate Noctiluca scintillans (Noctiluca) has the ability to reproduce sexually, which may help to increase or restore its population size during periods of blooms or environmental stress. Here, we documented for the first time a marine ciliate Strombidium sp. that feeds on Noctiluca's progametes undergoing stages 5 to 9 of nuclear division. This ciliate frequently swam on or around gametogenic and some vegetative Noctiluca cells. The ciliates associated with gametogenic cells had significantly lower swimming speed and changed direction more frequently than those associated with vegetative cells, which overall increased their time spent around the food patches (progametes)...
February 2017: Protist
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
Katrina M Pagenkopp Lohan, Robert C Fleischer, Mark E Torchin, Gregory M Ruiz
Deciphering patterns of protistan taxa is a crucial step for understanding anthropogenic and environmental impacts on biogeography. We characterized and compared protistan communities from environmental samples collected along a major shipping corridor, the Panama Canal, and the Bocas del Toro archipelago. We used metabarcoding with high throughput sequencing (HTS) with the V4 hypervariable region of the ribosomal gene complex (rDNA). We detected many protistan taxa, including a variety of parasitic and toxic taxa...
January 6, 2017: Protist
Izumi Iwata, Kei Kimura, Yuji Tomaru, Taizo Motomura, Kanae Koike, Kazuhiko Koike, Daiske Honda
Labyrinthulomycetes are characterized by the presence of ectoplasmic nets originating from an organelle known as the bothrosome, whose evolutionary origin is unclear. To address this issue, we investigated the developmental process from a zoospore to a vegetative cell in Schizochytrium aggregatum. After disappearance of the flagellum during zoospore settlement, the bothrosome emerged at the anterior-ventral pole of the cells. A new Golgi body also appeared at this stage, and the bothrosome was positioned close to both the new and the old Golgi bodies...
December 14, 2016: Protist
Helge Abildhauge Thomsen, Frank Nitsche, Daniel J Richter
It is a trend in loricate choanoflagellate research that our knowledge of species diversity is insufficient in terms of understanding annual successional changes at any specific locality, whereas there is a fairly decent coverage worldwide - at least in more coastal realms - in terms of biodiversity within more narrowly defined time windows. To help address this knowledge gap, we have compiled all available loricate choanoflagellate occurrence data from Danish sampling sites covering an overall time span of close to four decades...
December 2016: Protist
David Morse, Philip Daoust, Siham Benribague
Dinoflagellates are a group of unicellular and generally marine protists, of interest to many because of their ability to form the large algal blooms commonly called "red tides". The large algal concentrations in these blooms require sustained cell replication, yet to date little is known about cell cycle regulation in these organisms. To address this issue, we have screened the transcriptomes of two dinoflagellates, Lingulodinium polyedrum and Symbiodinium sp., with budding yeast cell cycle pathway components...
December 2016: Protist
Aika Yamaguchi, Sadaaki Yoshimatsu, Mona Hoppenrath, Kevin C Wakeman, Hiroshi Kawai
The genus Amphidiniopsis is a benthic (sand-dwelling) lineage of thecate dinoflagellates, containing 19 morphologically diverse species. Past work has shown that some Amphidiniopsis species form a clade with the sand-dwelling Herdmania litoralis as well as some planktonic species in the family Protoperidiniaceae (i.e. the Monovela group). Still, our contemporary knowledge regarding Amphidiniopsis is limited, compared to the Protoperidiniaceae. To this end, we obtained 18S rDNA data from seven Amphidiniopsis species and a part of the 28S rDNA from four Amphidiniopsis species, with the goal of improving our understanding of phylogenetic relationships among Amphidiniopsis and the Monovela group...
December 2016: Protist
Jie Xiao, Xiaoxiang Miao, Caiwen Li, Wenjun Xu, Xuelei Zhang, Zongling Wang
The parasitic dinoflagellate Hematodinium infects multiple cultured marine crustaceans and has resulted in significant economic losses to their aquaculture in China. Limited molecular data implied a close relationship among Hematodinium reported in China, whereas the genetic diversity and detailed genetic variation within Hematodinium remains unclear. In order to investigate the genetic diversity and composition of the parasitic dinoflagellate in China, the sequences of the internal transcribed spacer region (ITS1 - 5...
December 2016: Protist
Naoji Yubuki, Sam S C Huang, Brian S Leander
The Fornicata (Excavata) is a group of microbial eukaryotes consisting of both free-living lineages (e.g., Carpediemonas) and parasitic lineages (e.g. Giardia and Retortamonas) that share several molecular and ultrastructural traits. Carpediemonas-like organisms (CLOs) are free-living lineages that diverged early within the Fornicata, making them important for inferring the early evolutionary history of the group. Molecular phylogenetic analyses of free-living fornicates, including sequences from environmental PCR surveys, have demonstrated that CLOs form six different lineages...
December 2016: Protist
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