The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Jangseu Ki - One of the best experts on this subject based on the ideXlab platform.
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discriminative power of nuclear rdna sequences for the dna taxonomy of the dinoflagellate genus Peridinium dinophyceae 1
Journal of Phycology, 2011Co-Authors: Jangseu Ki, Myunghwan ParkAbstract:: The genus Peridinium Ehrenb. comprises a group of highly diversified dinoflagellates. Their morphological taxonomy has been established over the last century. Here, we examined relationships within the genus Peridinium, including Peridinium bipes F. Stein sensu lato, based on a molecular phylogeny derived from nuclear rDNA sequences. Extensive rDNA analyses of nine selected Peridinium species showed that intraspecies genetic variation was considerably low, but interspecies genetic divergence was high (>1.5% dissimilarity in the nearly complete 18S sequence; >4.4% in the 28S rDNA D1/D2). The 18S and 28S rDNA Bayesian tree topologies showed that Peridinium species grouped according to their taxonomic positions and certain morphological characters (e.g., epithecal plate formula). Of these groups, the quinquecorne group (plate formula of 3', 2a, 7″) diverged first, followed by the umbonatum group (4', 2a, 7″) and polonicum group (4', 1a, 7″). Peridinium species with a plate formula of 4', 3a, 7″ diverged last. Thus, 18S and 28S rDNA D1/D2 sequences are informative about relationships among Peridinium species. Statistical analyses revealed that the 28S rDNA D1/D2 region had a significantly higher genetic divergence than the 18S rDNA region, suggesting that the former as DNA markers may be more suitable for sequence-based delimitation of Peridinium. The rDNA sequences had sufficient discriminative power to separate P. bipes f. occultaum (Er. Lindem.) M. Lefevre and P. bipes f. globosum Er. Lindem. into two distinct species, even though these taxa are morphologically only marginally discriminated by spines on antapical plates and the shape of red bodies during the generation of cysts. Our results suggest that 28S rDNA can be used for all Peridinium species to make species-level taxonomic distinctions, allowing improved taxonomic classification of Peridinium.
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new record of the freshwater dinoflagellate Peridinium umbonatum stein dinophyceae from togyo reservoir korea
Algae, 2008Co-Authors: Jangseu KiAbstract:Cells of the dinoflagellate Peridinium were frequently observed in water samples of Togyo reservoir, and some species were responsible for dense blooms. Recently, we could identify them as P. bipes f. occultatum Lindem. and P. aciculiferum Lemm., considering morphology (Ki et al. 2005a; Ki and Han 2005b): However, some unidentified Peridinium cells with different shapes and body sizes were found among the samples collected during early spring. Here we describe their morphological characteristics such as thecal plate and body size to characterize its taxonomic identity by morphological characters. The formula of epithecal plates was recorded as 4 apical, 2 intercalary and 7 precingular plates (i.e. 4’`, 2a, 7’`’`) and the epicone in an apical view was symmetric. An apical pore was easy to make out under a light microscope. No cingular displacement was observed. The average body size was 33 m in length with a range of 26-36 m, and average 26 m in width with a range of 21-31 m, respectively; the cell was, therefore, shown slightly elongated. This way we identified Peridinium umbonatum Stein, 1883 for the first time from Korean freshwaters.
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rapid molecular identification of the harmful freshwater dinoflagellate Peridinium in various life stages using genus specific single cell pcr
Journal of Applied Phycology, 2007Co-Authors: Jangseu KiAbstract:Cysts of the freshwater dinoflagellate Peridinium are typically different from vegetative cells in shape and remain largely undescribed. Molecular discrimination of such cysts would be useful to a number of research disciplines. A reliable method for the amplification of ribosomal DNA (rDNA) from Peridinium at different life stages is described. This genotyping strategy relies on whole cell PCR using Peridinium-specific primers designed from available 18S rDNA sequences. Here, we demonstrate the effectiveness of Peridinium-specific PCR for the rapid molecular identification of Peridinium cells in various life stages such as vegetative, planozygote, hypnozygote and cyst.
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sequence based diagnostics and phylogenetic approach of uncultured freshwater dinoflagellate Peridinium dinophyceae species based on single cell sequencing of rdna
Journal of Applied Phycology, 2005Co-Authors: Jangseu KiAbstract:The armoured dinoflagellate Peridinium is widely distributed in freshwater environments worldwide and contains a large number of species. Their identity, however, has remained elusive, since the small cells tend to be morphologically similar. To help resolve this, a sequence-based diagnostics for uncultured Peridinium cells from field samples was applied, using single-cell PCR and direct DNA sequencing of the PCR products. Single cells were isolated randomly from field samples, and PCR successfully amplified the target rDNA regions from the crude lysates. Phylogenetic trees showed that all the cells were strongly grouped into the same clade (> 99% bootstrap value), including the previously identified P. bipes f. occultatum, and apparently separated from relatives such as P. cinctum, P. volzii and P. willei. All 17 isolates were genotypically identified as P. bipes f. occultatum, based on over than 99% of sequence similarities, and the organism was responsible for water blooms at different seasons in Korean waters. The sequence-based typing could clearly resolve P. bipes f. occultatum from the various Peridinium cells, and that the method is accurate and more labor-saving than the conventional method to monitor Peridinium species. This protocol may be useful for the application of molecular tools to uncultured Peridinium cells.
Susan Carty - One of the best experts on this subject based on the ideXlab platform.
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utex 1336 Peridinium cinctum or Peridinium volzii dinophyceae 1
Journal of Phycology, 2004Co-Authors: Lois A Pfiester, Susan CartyAbstract:Plate pattern variation in UTEX clone 1336 and published photographs using this clone indicate the presence of two taxa: Peridinium cinctum and Peridinium volzii. All subclones established from UTEX 1336 contain the same two cell types. The identification of UTEX 1336 and its future use by researchers are discussed.
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UTEX 1336: Peridinium CINCTUM OR Peridinium VOLZII (DINOPHYCEAE)?1
Journal of Phycology, 2004Co-Authors: Lois A Pfiester, Susan CartyAbstract:Plate pattern variation in UTEX clone 1336 and published photographs using this clone indicate the presence of two taxa: Peridinium cinctum and Peridinium volzii. All subclones established from UTEX 1336 contain the same two cell types. The identification of UTEX 1336 and its future use by researchers are discussed.
Lois A Pfiester - One of the best experts on this subject based on the ideXlab platform.
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utex 1336 Peridinium cinctum or Peridinium volzii dinophyceae 1
Journal of Phycology, 2004Co-Authors: Lois A Pfiester, Susan CartyAbstract:Plate pattern variation in UTEX clone 1336 and published photographs using this clone indicate the presence of two taxa: Peridinium cinctum and Peridinium volzii. All subclones established from UTEX 1336 contain the same two cell types. The identification of UTEX 1336 and its future use by researchers are discussed.
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UTEX 1336: Peridinium CINCTUM OR Peridinium VOLZII (DINOPHYCEAE)?1
Journal of Phycology, 2004Co-Authors: Lois A Pfiester, Susan CartyAbstract:Plate pattern variation in UTEX clone 1336 and published photographs using this clone indicate the presence of two taxa: Peridinium cinctum and Peridinium volzii. All subclones established from UTEX 1336 contain the same two cell types. The identification of UTEX 1336 and its future use by researchers are discussed.
Tamar Zohary - One of the best experts on this subject based on the ideXlab platform.
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interactions between the bloom forming dinoflagellate Peridinium gatunense and the chytrid fungus phlyctochytrium sp
Hydrobiologia, 2007Co-Authors: Alla Alster, Tamar ZoharyAbstract:Epidemic chytrid fungal infection of Peridinium gatunense, the major bloom-forming dinoflagellate in Lake Kinneret, Israel, is reported for the first time. The fungus, identified as Phlyctochytrium sp. based on morphological and life cycle characteristics, was first observed in December 2000. It rapidly developed into an epidemic, coinciding with a 1000-fold decline in Peridinium density within 9 days of the initial observation of the chytrid. In August 2001 a second fungal epidemic occurred, which was again associated with a Peridinium population crash. In 2002–2003 less dramatic fungal epidemics were recorded, infection prevalence was low and the Peridinium population did not crash. Laboratory experiments demonstrated that healthy Peridinium cells are not prone to fungal infection, mostly stressed or dead cells were infected. In other words, Phlyctochytrium is a saprophyte, possibly a facultative parasite of Peridinium. Probably another pathogen was responsible for the observed bloom crashes and the saprophytic Phlyctochytrium was a secondary parasite, infecting the already moribund cells. The emergence of fungal epidemics in Lake Kinneret could be interpreted as an early signal of ecosystem response to increasing anthropogenic stress.
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encystment of Peridinium gatunense occurrence favourable environmental conditions and its role in the dinoflagellate life cycle in a subtropical lake
Freshwater Biology, 2006Co-Authors: Alla Alster, Zvy Dubinsky, Tamar ZoharyAbstract:Summary 1. The abundance of cysts of the bloom-forming dinoflagellate Peridinium gatunense in the sediments of Lake Kinneret and the effects of environmental conditions on encystment were studied in relation to bloom dynamics. Peak cyst formation coincided with the highest growth rate of the population, prior to bloom peak. 2. Peridinium cysts were counted in water and sediment corer samples from 2000 to 2003 and in archived sediment trap samples collected during 1993–94. The cyst data were examined in relation to ambient temperature and nutrient records, and revealed no direct correlation. 3. In laboratory encystment experiments with Peridinium cells collected from the lake, 0.2–3% of the vegetative cells encysted. Temperature, light and cell density had no significant effect on the percentage of encystment. 4. Cysts were always present in the lake sediments but their abundance in ‘non Peridinium’ years was much lower than after a massive bloom. Vegetative cells were always present in the water column after the collapse of the annual dinoflagellate bloom, potentially serving as the inoculum for the next bloom. We propose that the hardy cysts serve as an emergency ‘gene bank’ to initiate population build up following catastrophic die outs.
Lois A Pfester - One of the best experts on this subject based on the ideXlab platform.
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the effects of temperature irradiance and nitrogen on the encystment and growth of the freshwater dinoflagellates Peridinium cinctum and p willei in culture dinophyceae 1
Journal of Phycology, 1995Co-Authors: Andrew D Chapman, Lois A PfesterAbstract:Effects of temperature, irradiance, and nitrogen availability on the encystment and growth of the freshwater dinoflagellates Peridinium cinctum Ehrenberg and Peridinium willei Huitfeld-Kaas were studied in culture. Lack of nitrogen was the main trigger of encystment in both species. Irradiance had a secondary effect on the percentage of the population of each species that encysted. Temperature did not significantly affect encystment in either species. In both species, only a small percentage of the population underwent encystment. Low light had an inhibitory effect on the growth of P. willei growing in nitrogen-sufficient medium.
