Lunachloris lukesovae gen. et sp. nov. (Trebouxiophyceae,Chlorophyta), a novel coccoid green alga isolated from soil in South Bohemia,Czech Republic

Culture collections of microorganisms can still hold undiscovered biodiversity; with molecular techniques, considerable progress has been made in characterizing microalgae which were isolated in the past and misidentified due to a lack of morphological features. However, many strains are still awaiting taxonomic reassessment. Here we analysed the phylogenetic position, morphology and ultrastructure of the strain CCALA 307 previously identified as Coccomyxa cf. gloeobotrydiformis Reysigl isolated in 1987 from field soil in South Bohemia, Czech Republic. Molecular phylogenetic analyses based on SSU rDNA and the plastid rbcL gene revealed that the strain CCALA 307 formed a distinct sister lineage to Neocystis and Prasiola clades within the Trebouxiophyceae. We describe this strain as a new genus and species, Lunachloris lukesovae. Multiple conserved nucleotide positions identified in the secondary structures of the highly variable ITS2 rDNA barcoding marker provide further evidence of the phylogenetic position of Lunachloris. Minute vegetative cells of this newly recognized species are spherical or ellipsoid, with a single parietal chloroplast without a pyrenoid. Asexually, it reproduces by the formation of 2–6 autospores. Since the majority of recent attention has been paid to algae from the tropics or extreme habitats, the biodiversity of terrestrial microalgae in temperate regions is still notably unexplored and even a ‘common’ habitat like agricultural soil can contain new, as yet unknown species. Moreover, this study emphasizes the importance of culture collections of microorganisms even in the era of culture-independent biodiversity research, because they may harbour novel and undescribed organisms as well as preserving strains for future studies.     

Plastid‐encoded rbcL phylogeny suggests widespread distribution of Galdieria phlegrea (Cyanidiophyceae,Rhodophyta)

The rare microscopic red alga Galdieria phlegrea (Cyanidiohyceae, Rhodophyta) has been discovered in the extremely acid Tinto River in Spain and this occurrence is here related to previous knowledge about the distribution and ecology of this enigmatic alga. The taxonomic affiliation of the new isolate of G. phlegrea was revealed by reconstructing the phylogeny of plastid‐encoded rbcL. According to this phylogeny, the Tinto River alga is closely related to other G. phlegrea strains originating from extreme habitats in Czechia, Italy and Turkey, suggesting a wider distribution and higher ecological versatility than previously thought. The results suggest that G. phlegrea, and then possibly also other cyanidiophycean algae, are not as restricted to strongly acidic and hot microhabitats as previously believed, which, in turn, may indicate that they may commonly have been overlooked and possibly are much more widespread than is currently believed.     

A molecular approach to identification of protonemata helps assess biodiversity of extremely acidic freshwaters

Limnology - Macroscopic fuzzy clumps of green filaments resembling filamentous algae were found on multiple sampling occasions in the water close to the shore of the extremely acidic...     

The Arctic Cylindrocystis (Zygnematophyceae,Streptophyta) Green Algae are Genetically and Morphologically Diverse and Exhibit Effective Accumulation of Polyphosphate

The green algal genus Cylindrocystis is widespread in various types of environments, including extreme habitats. However, very little is known about its diversity, especially in polar regions. In the present study, we isolated seven new Cylindrocystis-like strains from terrestrial and freshwater habitats in Svalbard (High Arctic). We aimed to compare the new isolates on a molecular (rbcL and 18S rDNA), morphological (light and confocal laser scanning microscopy), and cytological (Raman microscopy) basis. Our results demonstrated that the Arctic Cylindrocystis were not of a monophyletic origin and that the studied strains clustered within two clades (tentatively named the soil and freshwater/glacier clades) and four separate lineages. Morphological data (cell size, shape, and chloroplast morphology) supported the presence of several distinct taxa among the new isolates. Moreover, the results showed that the Arctic Cylindrocystis strains were closely related to strains originating from the temperate zone, indicating high ecological versatility and successful long-distance dispersal of the genus. Large amounts of inorganic polyphosphate (polyP) grains were detected within the chloroplasts of the cultured Arctic Cylindrocystis strains, suggesting effective luxury uptake of phosphorus. Additionally, various intracellular structures were identified using Raman microscopy and cytochemical and fluorescent staining. This study represents the first attempt to combine molecular, morphological, ecological, and biogeographical data for Arctic Cylindrocystis. Our novel cytological observations partially explain the success of Cylindrocystis-like microalgae in polar regions.     

Skin extracellular matrix components accelerate the regenerative potential of Lin− cells

Due to their unique properties, bone marrow-derived Lin^? cells can be used to regenerate damaged tissues, including skin. The objective of our study was to determine the influence of the skin tissue-specific microenvironment on mouse Lin^? cell proliferation and migration in vitro. Cells were analyzed for the expression of stem/progenitor surface markers by flow cytometry. Proliferation of MACS-purified cells in 3D cultures was investigated by WST-8 assay. Lin^? cell migration was evaluated by in vitro scratch assay. The results obtained show that basement membrane matrix is more effective for Lin^? cell proliferation in vitro. However, type I collagen matrix better enhances the re-epithelization process, that depends on the cell migratory properties. These studies are important for preparing cells to be used in transplantation.     

Proteomic and gene expression differences between post-diapause and subitaneous offspring phenotypes in the cyclic parthenogen <Emphasis Type="Italic">Daphnia pulex</Emphasis>

In temperate waters, post-diapause and subitaneous offspring in Daphnia vary in life history traits and metabolic rates, and presumably are adapted to the seasonal environments in which they dwell. These offspring types result from different developmental programs of the same genetic background, representing the phenomenon of phenotypic plasticity. We aimed to explore the molecular mechanism of this phenotypic plasticity in Daphnia pulex from an intermittent population by applying a high-throughput proteomic analysis and expression analysis of several genes. The study revealed 176 proteins that were differentially expressed among offspring phenotypes. Post-diapause and subitaneous females clearly differed in their upregulated protein profiles and gene expression levels. There were more upregulated proteins with oxidoreductase and binding activity in post-diapause offspring, whereas more upregulated proteins with transporter and transferase activity were seen in subitaneous offspring. In contrast to subitaneous phenotype, over 1.5-fold more of the proteins that were upregulated in post-diapause phenotype are involved in metabolism and biosynthesis. Expression levels of several selected genes linked to cellular metabolism were also higher in post-diapause females. The greatest difference, 5-fold upregulation in post-diapause compared to subitaneous offspring, was recorded for the target of rapamycin-like (TOR) protein. Expression of ribosomal proteins in this offspring phenotype was also increased. These upregulations suggest that the TOR signaling pathway is involved and may be responsible for the regulation of the developmental program underlying post-diapause and subitaneous offspring phenotypes in Daphnia. Gene regulatory patterns observed in post-diapause and subitaneous offspring were in agreement with the expectations based on previously observed organismal traits of these Daphnia offspring types.     

Coccomyxa: a dominant planktic alga in two acid lakes of different origin

Extremophiles - The aim of this study was to reveal the taxonomic position and phylogenetic relationships of the dominant planktic algae in two acid metal-rich lakes of different origin (Hromnice...