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The freshwater testate filose amoeba Paulinella chromatophora is the sole species in the genus to have plastids, usually termed “chromatophores”, of a Synechococcus/Prochlorococcus-like cyanobacterial origin. Here, we report a new marine phototrophic species, Paulinella longichromatophora sp. nov., using light and electron microscopy and molecular data. This new species contains two blue-green U-shaped...
Trypanosoma copemani has been found infecting several threatened/endangered marsupial species within Australia and is thought to be a key player in the rapid decline of the woylie (Bettongia penicillata). To better understand the biology and life cycle of this parasite, the growth requirements, and kinetics of infection of two newly described genotypes, T. copemani G1 and G2, were investigated and...
Six viable strains of amoebae belonging to the genus Flamella (Amoebozoa, Variosea) were isolated from permafrost sediments sampled in the Russian Arctic region. Two of them are from late Pleistocene permafrost in North-East Siberia, and four - from Holocene and late Pleistocene in North-West Siberia. Light- and electron-microscopic study and molecular phylogeny show that these isolates represent...
The daily photosynthetic performance of a natural biofilm of the extreme acidophilic Euglena mutabilis from Río Tinto (SW, Spain) under full solar radiation was analyzed by means of pulse amplitude-modulated (PAM) fluorescence measurements and metatrascriptomic analysis. Natural E. mutabilis biofilms undergo large-scale transcriptomic reprogramming during midday due to a dynamic photoinhibition and...
Centrohelid heliozoans are non-ciliary axopodial protists of uncertain affinities. Cell coverings (organic spicules, siliceous plate-scales and spine-scales) are the main character for their taxonomy. Phylogenetic reconstructions of this group are mostly based on the sequences of 18S rDNA. Here molecular and microscopical data on Raphidiophrys heterophryoidea, R. drakena sp. nov., Spiculophrys agregata...
Prorocentrum micans is an extremely variable dinoflagellate species, with many different local forms reported worldwide. Because of this morphological diversity, it is important to establish whether these various forms belong to P. micans sensu stricto. For this study, P. micans-like specimens were isolated from several localities in the southern coastal waters of Korea and Japan. The morphological...
Benthic diatoms represent an important component of aquatic ecosystems, both for their contribution to primary production and their role in the marine food web. Mastogloia is a large, mostly marine diatom genus occurring in microphytobenthic communities of temperate to tropical coastal regions. In this study, the phylogenetic relationships, based on cladistic methodologies using morphological features,...
Little is known about nucleosome structure and epigenetic regulation of transcription of rRNA genes in early-branched eukaryotes. Here we analyze the chromatin architecture and distribution of some histone modifications in the rRNA genes in the parasitic protozoon Leishmania major. Southern blots of MNase-partially-digested chromatin with DNA probes spanning the whole rRNA gene repeat showed that...
Many freshwater protists harbor unicellular green algae within their cells, but little is known of their degree of integration and specificity. Using algae-targeted PCR of whole ciliate cells collected at irregular intervals over 15 months from Lake Biwa, Japan, we explored the SSU-ITS rDNA of the endosymbiotic algae and its changes over time, obtaining sequences of algal rDNA fragments from four...
In the last decade, field studies in the northern Arabian Sea showed a drastic shift from diatom-dominated phytoplankton blooms to thick and widespread blooms of the green dinoflagellate, Noctiluca scintillans. Unlike the exclusively heterotrophic red form, which occurs widely in tropical to temperate coastal waters, the green Noctiluca contains a large number of endosymbiotic algal cells that can...
Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic...
Respiratory oxygen consumption rate (RO2) and potential respiration (Φ) has been monitored during a food deprivation period in the heterotrophic dinoflagellate Oxyrrhis marina. Φ was determined by measuring the activity of the enzymes from the electron transport system (ETS), the major contributor to the oxygen consumption in the cells. Additionally, we have quantified for the first time the concentration...
Testate amoebae have been frequently studied by protistologists, but still little information is available on some groups like the Chlamydophryidae. These amoebae are difficult to culture and therefore quantitative information on their morphology, phylogeny and ecology is scarce. We isolated and cultured a small testate amoeba from an agricultural field at Müncheberg near Berlin, Germany. Morphological...
Studies of the lowland avifauna in the Neotropical Region have shown a paucity of Leucocytozoon species. However, surveys conducted in the Colombian highlands revealed a great diversity of these parasites infecting resident birds. To further investigate the relationship between Leucocytozoon diversity, the potential vectors, and altitudinal distribution, birds from 41 families were sampled at low...
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