Molecular and Morphological Investigations of the Stauros-bearing, Raphid Pennate Diatoms (Bacillariophyceae): Craspedostauros E.J. Cox, and Staurotropis T.B.B. Paddock, and their Relationship to the Rest of the Mastogloiales
Publication date: Available online 17 November 2016 Source:Protist Author(s): 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...
Source: Protist - November 17, 2016 Category: Molecular Biology Source Type: research
The Cytoskeleton Architecture of Algivorous Protoplast Feeders (Viridiraptoridae, Rhizaria) Indicates Actin –Guided Perforation of Prey Cell Walls
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. During attack, both species form distinctive, F–actin–rich structures at the contact zone to the algal prey cell, which exactly match the species–specific cell wall perforations and resemble invadopodia and podosome rosettes of mammalian cells to a certain extent. Furthermore, F–actin is involved in the extraction of plastid material by Orciraptor and in prey cell invasion by Viridir...
Source: Protist - October 31, 2016 Category: Molecular Biology Source Type: research
Cobalamin-independent Methionine synthase distribution and Influence on Vitamin B12 Growth Requirements in Marine Diatoms
Publication date: Available online 25 October 2016 Source:Protist Author(s): 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 methioni...
Source: Protist - October 25, 2016 Category: Molecular Biology Source Type: research
Phylogeny and Systematics of Leptomyxid Amoebae (Amoebozoa, Tubulinea, Leptomyxida)
We describe four new species of Flabellula, Leptomyxa and Rhizamoeba and publish new SSU rRNA gene and actin gene sequences of leptomyxids. Using these data we provide the most comprehensive SSU phylogeny of leptomyxids to date. Based on the analyses of morphological data and results of the SSU rRNA gene phylogeny we suggest changes in the systematics of the order Leptomyxida (Amoebozoa: Lobosa: Tubulinea). We propose to merge the genera Flabellula and Paraflabellula (the genus Flabellula remains valid by priority rule). The genus Rhizamoeba is evidently polyphyletic in all phylogenetic trees; we suggest retaining the gene...
Source: Protist - October 25, 2016 Category: Molecular Biology Source Type: research
Clarification of Photorespiratory Processes and the Role of Malic Enzyme in Diatoms
Publication date: Available online 21 October 2016 Source:Protist Author(s): 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 glyox...
Source: Protist - October 21, 2016 Category: Molecular Biology Source Type: research
Comparative Ultrastructure of Fornicate Excavates, Including a Novel Free-living Relative of Diplomonads: Aduncisulcus palustris gen. et sp. nov.
Publication date: Available online 18 October 2016 Source:Protist Author(s): 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...
Source: Protist - October 18, 2016 Category: Molecular Biology Source Type: research
Genetic Variations of the Parasitic Dinoflagellate Hematodinium Infecting Cultured Marine Crustaceans in China
Publication date: Available online 17 October 2016 Source:Protist Author(s): 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 sequenc...
Source: Protist - October 17, 2016 Category: Molecular Biology Source Type: research
A Transcriptome-based Perspective of Cell Cycle Regulation in Dinoflagellates
Publication date: Available online 17 October 2016 Source:Protist Author(s): 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 pa...
Source: Protist - October 17, 2016 Category: Molecular Biology Source Type: research
Warming and Acidification Effects on Planktonic Heterotrophic Pico- and Nanoflagellates in a Mesocosm Experiment
Publication date: August 2016 Source:Protist, Volume 167, Issue 4 Author(s): Maria Moustaka-Gouni, Konstantinos A. Kormas, Marco Scotti, Elisabeth Vardaka, Ulrich Sommer We studied the response of the heterotrophic flagellate (HF) community to the combined impact of warming and ocean acidification in a mesocosm experiment with a plankton community from the western Baltic Sea. We performed a quantitative analysis of the response at the level of total biomass and size classes and a semi-quantitative one at the level of individual taxa. Total biomass of HF was significantly lower under higher temperatures while there w...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
Transcripts in the Plasmodium Apicoplast Undergo Cleavage at tRNAs and Editing, and Include Antisense Sequences
Publication date: August 2016 Source:Protist, Volume 167, Issue 4 Author(s): R. Ellen R. Nisbet, Davy P. Kurniawan, Harrison D. Bowers, Christopher J. Howe The apicoplast, an organelle found in Plasmodium and many other parasitic apicomplexan species, is a remnant chloroplast that is no longer able to carry out photosynthesis. Very little is known about primary transcripts and RNA processing in the Plasmodium apicoplast, although processing in chloroplasts of some related organisms (chromerids and dinoflagellate algae) shows a number of unusual features, including RNA editing and the addition of 3′ poly(U) tails. H...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
Automatized Freeze Substitution of Algae Accelerated by a Novel Agitation Module
Publication date: August 2016 Source:Protist, Volume 167, Issue 4 Author(s): Helmuth Goldammer, Elena Hollergschwandtner, Nathalie H. Elisabeth, Pedro R. Frade, Siegfried Reipert (Source: Protist)
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
A Cryptic Marine Ciliate Feeds on Progametes of Noctiluca scintillans
Publication date: Available online 31 August 2016 Source:Protist Author(s): 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 ci...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
Molecular Phylogeny of the Benthic Dinoflagellate Genus Amphidiniopsis and its Relationships with the Family Protoperidiniaceae
Publication date: Available online 6 October 2016 Source:Protist Author(s): 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, w...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
Seasonal Occurrence of Loricate Choanoflagellates in Danish Inner Waters
Publication date: Available online 6 October 2016 Source:Protist Author(s): 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 coveri...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
Barcoding Heliozoa: Perspectives of 18S rDNA for Distinguishing Between Acanthocystis Species
Publication date: Available online 14 October 2016 Source:Protist Author(s): Vasily V. Zlatogursky, Vladimir I. Klimov The first application of DNA-barcoding for the centrohelids is reported. The character-rich genus Acanthocystis was chosen to compare sequence divergence and morphological similarity. Acanthocystis nichollsi, an easily identifiable and well outlined species, was isolated from four remote locations; A. costata; A. takahashii (2 strains) and A. turfacea were studied as well. Detailed light- and electron-microscopic data were obtained and a fragment of 18S rDNA (mostly V5 to V8 regions) was cloned and mul...
Source: Protist - October 14, 2016 Category: Molecular Biology Source Type: research
