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Pavel Škaloud - One of the best experts on this subject based on the ideXlab platform.
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morphological evolution of silica scales in the freshwater genus Synura stramenopiles
Journal of Phycology, 2021Co-Authors: Iva Jadrna, Peter A Siver, Pavel ŠkaloudAbstract:A high degree of morphological variability is expressed between the ornately sculptured siliceous scales formed by species in the chrysophycean genus, Synura. In this study, we aimed to uncover the general principles and trends underlying the evolution of scale morphology in this genus. We assessed the relationships among thirty extant Synura species using a robust molecular analysis that included six genes, coupled with morphological characterization of the species-specific scales. The analysis was further enriched with addition of morphological information from fossil specimens and by including the unique modern species, Synura punctulosa. We inferred the phylogenetic position of the morphologically unique S. punctulosa, to be an ancient Synura lineage related to S. splendida in the section Curtispinae. Some morphological traits, including development of a keel or a labyrinth ribbing pattern on the scale, appeared once in evolution, whereas other structures, such as a hexagonal meshwork pattern, originated independently several times over geologic time. We further uncovered numerous construction principles governing scale morphology and evolution, as follows: (i) scale roundness and pore diameter decreased during evolution; (ii) elongated scales became strengthened by a higher number of struts or ribs; (iii) as a consequence of scale biogenesis, scales with spines possessed smaller basal holes than scales with a keel and; and (iv) the keel area was proportional to scale area, indicating its potential value in strengthening the scale against breakage.
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comparing morphological and molecular estimates of species diversity in the freshwater genus Synura stramenopiles a model for understanding diversity of eukaryotic microorganisms
Journal of Phycology, 2020Co-Authors: Pavel Škaloud, Magda Škaloudová, Iva Jadrna, Dmitry A Kapustin, Helena Bestova, Martin Pusztai, Peter A SiverAbstract:We performed a comparison of molecular and morphological diversity in a freshwater colonial genus Synura (Chrysophyceae, Stramenopiles), using the island of Newfoundland (Canada) as a case study. We examined the morphological species diversity in collections from 79 localities, and compared these findings to diversity based on molecular characters for 150 strains isolated from the same sites. Of 27 species or species-level lineages identified, only one third was recorded by both molecular and morphological techniques, showing both approaches are complementary in estimating species diversity within this genus. Eight taxa, each representing young evolutionary lineages, were recovered only by sequencing of isolated colonies, whereas ten species were recovered only microscopically. Our complex investigation, involving both morphological and molecular examinations, indicates that our knowledge of Synura diversity is still poor, limited only to a few well-studied areas. We revealed considerable cryptic diversity within the core S. petersenii and S. leptorrhabda lineages. We further resolved the phylogenetic position of two previously described taxa, S. kristiansenii and S. petersenii f. praefracta, propose species-level status for S. petersenii f. praefracta, and describe three new species, S. vinlandica, S. fluviatilis, and S. cornuta. Our findings add to the growing body of literature detailing distribution patterns observed in the genus, ranging from cosmopolitan species, to highly restricted taxa, to species such as S. hibernica found along coastal regions on multiple continents. Finally, our study illustrates the usefulness of combining detailed morphological information with gene sequence data to examine species diversity within chrysophyte algae.
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multigene phylogeny of Synura synurophyceae and descriptions of four new species based on morphological and dna evidence
European Journal of Phycology, 2016Co-Authors: Jong Im Kim, Pavel Škaloud, Peter A Siver, Woongghi ShinAbstract:We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new ...
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Multigene phylogeny of Synura (Synurophyceae) and descriptions of four new species based on morphological and DNA evidence
2016Co-Authors: Jong Im Kim, Pavel Škaloud, Peter A Siver, Woongghi ShinAbstract:We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new sectional ranks; Synura, Peterseniae, Curtispinae (presence of body scales with slender spines, tubular scales and caudal scales). We further propose four new species based on phylogenetic analyses and unique scale characters: S. longitubularis sp. nov., S. sungminbooi sp. nov., S. soroconopea sp. nov. and S. lanceolata sp. nov. Lastly, we propose a new genus name, Neotessella, to replace the invalid use of the name Tessellaria.
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morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex chrysophyceae stramenopiles
European Journal of Phycology, 2014Co-Authors: Pavel Škaloud, Magda Škaloudová, Anna Prochazkova, Yvonne NěmcováAbstract:The Synura petersenii species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (S. borealis, S. heteropora, S. hibernica and S. laticarina) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the S. petersenii complex. Two of these newly described species (S. hibernica and S. borealis) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in S. hibernica could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, S. borealis possesses an exceptionally high degree of genetic diversity, possibly indicating...
Peter A Siver - One of the best experts on this subject based on the ideXlab platform.
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morphological evolution of silica scales in the freshwater genus Synura stramenopiles
Journal of Phycology, 2021Co-Authors: Iva Jadrna, Peter A Siver, Pavel ŠkaloudAbstract:A high degree of morphological variability is expressed between the ornately sculptured siliceous scales formed by species in the chrysophycean genus, Synura. In this study, we aimed to uncover the general principles and trends underlying the evolution of scale morphology in this genus. We assessed the relationships among thirty extant Synura species using a robust molecular analysis that included six genes, coupled with morphological characterization of the species-specific scales. The analysis was further enriched with addition of morphological information from fossil specimens and by including the unique modern species, Synura punctulosa. We inferred the phylogenetic position of the morphologically unique S. punctulosa, to be an ancient Synura lineage related to S. splendida in the section Curtispinae. Some morphological traits, including development of a keel or a labyrinth ribbing pattern on the scale, appeared once in evolution, whereas other structures, such as a hexagonal meshwork pattern, originated independently several times over geologic time. We further uncovered numerous construction principles governing scale morphology and evolution, as follows: (i) scale roundness and pore diameter decreased during evolution; (ii) elongated scales became strengthened by a higher number of struts or ribs; (iii) as a consequence of scale biogenesis, scales with spines possessed smaller basal holes than scales with a keel and; and (iv) the keel area was proportional to scale area, indicating its potential value in strengthening the scale against breakage.
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comparing morphological and molecular estimates of species diversity in the freshwater genus Synura stramenopiles a model for understanding diversity of eukaryotic microorganisms
Journal of Phycology, 2020Co-Authors: Pavel Škaloud, Magda Škaloudová, Iva Jadrna, Dmitry A Kapustin, Helena Bestova, Martin Pusztai, Peter A SiverAbstract:We performed a comparison of molecular and morphological diversity in a freshwater colonial genus Synura (Chrysophyceae, Stramenopiles), using the island of Newfoundland (Canada) as a case study. We examined the morphological species diversity in collections from 79 localities, and compared these findings to diversity based on molecular characters for 150 strains isolated from the same sites. Of 27 species or species-level lineages identified, only one third was recorded by both molecular and morphological techniques, showing both approaches are complementary in estimating species diversity within this genus. Eight taxa, each representing young evolutionary lineages, were recovered only by sequencing of isolated colonies, whereas ten species were recovered only microscopically. Our complex investigation, involving both morphological and molecular examinations, indicates that our knowledge of Synura diversity is still poor, limited only to a few well-studied areas. We revealed considerable cryptic diversity within the core S. petersenii and S. leptorrhabda lineages. We further resolved the phylogenetic position of two previously described taxa, S. kristiansenii and S. petersenii f. praefracta, propose species-level status for S. petersenii f. praefracta, and describe three new species, S. vinlandica, S. fluviatilis, and S. cornuta. Our findings add to the growing body of literature detailing distribution patterns observed in the genus, ranging from cosmopolitan species, to highly restricted taxa, to species such as S. hibernica found along coastal regions on multiple continents. Finally, our study illustrates the usefulness of combining detailed morphological information with gene sequence data to examine species diversity within chrysophyte algae.
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investigations of two celled colonies of Synura formerly described as chrysodidymus with descriptions of two new species
European Journal of Phycology, 2018Co-Authors: Peter A Siver, Dmitry A Kapustin, Eugeniy GusevAbstract:The two-celled colonial synurophyte genus Chrysodidymus was originally distinguished from its close relative Synura on the basis of the colonies always being of two cells, the shape of the cells an...
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multigene phylogeny of Synura synurophyceae and descriptions of four new species based on morphological and dna evidence
European Journal of Phycology, 2016Co-Authors: Jong Im Kim, Pavel Škaloud, Peter A Siver, Woongghi ShinAbstract:We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new ...
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Multigene phylogeny of Synura (Synurophyceae) and descriptions of four new species based on morphological and DNA evidence
2016Co-Authors: Jong Im Kim, Pavel Škaloud, Peter A Siver, Woongghi ShinAbstract:We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new sectional ranks; Synura, Peterseniae, Curtispinae (presence of body scales with slender spines, tubular scales and caudal scales). We further propose four new species based on phylogenetic analyses and unique scale characters: S. longitubularis sp. nov., S. sungminbooi sp. nov., S. soroconopea sp. nov. and S. lanceolata sp. nov. Lastly, we propose a new genus name, Neotessella, to replace the invalid use of the name Tessellaria.
Magda Škaloudová - One of the best experts on this subject based on the ideXlab platform.
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comparing morphological and molecular estimates of species diversity in the freshwater genus Synura stramenopiles a model for understanding diversity of eukaryotic microorganisms
Journal of Phycology, 2020Co-Authors: Pavel Škaloud, Magda Škaloudová, Iva Jadrna, Dmitry A Kapustin, Helena Bestova, Martin Pusztai, Peter A SiverAbstract:We performed a comparison of molecular and morphological diversity in a freshwater colonial genus Synura (Chrysophyceae, Stramenopiles), using the island of Newfoundland (Canada) as a case study. We examined the morphological species diversity in collections from 79 localities, and compared these findings to diversity based on molecular characters for 150 strains isolated from the same sites. Of 27 species or species-level lineages identified, only one third was recorded by both molecular and morphological techniques, showing both approaches are complementary in estimating species diversity within this genus. Eight taxa, each representing young evolutionary lineages, were recovered only by sequencing of isolated colonies, whereas ten species were recovered only microscopically. Our complex investigation, involving both morphological and molecular examinations, indicates that our knowledge of Synura diversity is still poor, limited only to a few well-studied areas. We revealed considerable cryptic diversity within the core S. petersenii and S. leptorrhabda lineages. We further resolved the phylogenetic position of two previously described taxa, S. kristiansenii and S. petersenii f. praefracta, propose species-level status for S. petersenii f. praefracta, and describe three new species, S. vinlandica, S. fluviatilis, and S. cornuta. Our findings add to the growing body of literature detailing distribution patterns observed in the genus, ranging from cosmopolitan species, to highly restricted taxa, to species such as S. hibernica found along coastal regions on multiple continents. Finally, our study illustrates the usefulness of combining detailed morphological information with gene sequence data to examine species diversity within chrysophyte algae.
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morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex chrysophyceae stramenopiles
European Journal of Phycology, 2014Co-Authors: Pavel Škaloud, Magda Škaloudová, Anna Prochazkova, Yvonne NěmcováAbstract:The Synura petersenii species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (S. borealis, S. heteropora, S. hibernica and S. laticarina) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the S. petersenii complex. Two of these newly described species (S. hibernica and S. borealis) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in S. hibernica could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, S. borealis possesses an exceptionally high degree of genetic diversity, possibly indicating...
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Toward a revision of the genus Synura, section Petersenianae (Synurophyceae, Heterokontophyta): morphological characterization of six pseudo-cryptic species
Phycologia, 2012Co-Authors: Pavel Škaloud, Anna Kynčlová, Oldřich Benada, Olga Kofroňová, Magda ŠkaloudováAbstract:Skaloud P., Kynclova A., Benada O., Kofroňova O. and Skaloudova M. 2012. Toward a revision of the genus Synura, section Petersenianae (Synurophyceae, Heterokontophyta): morphological characterization of six pseudo-cryptic species. Phycologia 51: 303–329. DOI: 10.2216/11-20.1 Morphological data, based on transmission and scanning electron microscopy of silica scales, are provided for six genetic lineages of the Synura petersenii species complex as revealed by multiple genetic markers (internal transcribed spacer rDNA, psaA, rbcL and cox1). The morphology allows clear distinction of all six lineages, as well as their separation from all other taxa in section Petersenianae. The lineages are redefined or described as new species in accordance with previously published molecular and morphometric evidence as S. petersenii, S. glabra, S. truttae comb. et stat. nov., S. americana sp. nov., S. macropora sp. nov. and S. conopea sp. nov. The section Petersenianae further includes nine taxa with well-known ultrastruc...
Yvonne Němcová - One of the best experts on this subject based on the ideXlab platform.
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Silica-scaled chrysophytes of southern Bohemian water bodies, including Mallomonas conspersa Dürrschmidt with occurrence so far reported from Japan and New Zealand. Fottea 9: 9399
2016Co-Authors: Kateřina Janatková, Yvonne NěmcováAbstract:Abstract: Silica-scaled chrysophytes are often important components of the phytoplankton community of freshwater lakes and reservoirs. A total of 25 taxa were recorded during an investigation of Borkovická Blata peat-bog and Novohradské Hory ponds, representing five genera. Along with cosmopolitan and widely distributed species, rare Synura mollispina, Mallomonas conspersa, M. retifera and M. kalinae were found. This study also represent only the third time that M. conspersa has ever been reported and documented by scale microphotographs. This taxon has so far been reported only from Japan and New Zealand. The close resemblance of scale morphology to M. retifera is discussed. Synura mollispina, M. conspersa and M. pumilio var. munda are recorded for the first time from the territory of the Czech Republic
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DOI: 10.2478/s11756-009-0181-9 The rare species Synura lapponica (Synurophyceae) new to the Czech Republic, local vs. global diversity in colonial synurophytes
2016Co-Authors: Yvonne Němcová, Martina PichrtováAbstract:Abstract: Synura lapponica Skuja, a freshwater colonial flagellate (Synurophyceae, Stramenopila), has been reported for the first time in the Czech Republic. This study evaluates the ecological requirements of the species, and includes a survey of the literature. Although S. lapponica has been reported thus far only in the Northern Hemisphere, the probability of its bipolar distribution is relatively high (22%). Distribution is probably ecologically determined, water temperature (correlated with latitude or seasonal fluctuations), and lower pH seem to be the primary environmental variables. A local vs. global ratio reflects, to a certain extent, the degree of sampling effort expended in the studied area, but a considerable increase in the number of revealed taxa was apparent when the area was expanded. Key words: Synura lapponica; Synurophyceae; distribution; ecological requirements; silica-scaled chrysophyte
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morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex chrysophyceae stramenopiles
European Journal of Phycology, 2014Co-Authors: Pavel Škaloud, Magda Škaloudová, Anna Prochazkova, Yvonne NěmcováAbstract:The Synura petersenii species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (S. borealis, S. heteropora, S. hibernica and S. laticarina) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the S. petersenii complex. Two of these newly described species (S. hibernica and S. borealis) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in S. hibernica could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, S. borealis possesses an exceptionally high degree of genetic diversity, possibly indicating...
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The rare species Synura lapponica (Synurophyceae) new to the Czech Republic, local vs. global diversity in colonial synurophytes
Biologia, 2009Co-Authors: Yvonne Němcová, Martina PichrtováAbstract:Synura lapponica Skuja, a freshwater colonial flagellate (Synurophyceae, Stramenopila), has been reported for the first time in the Czech Republic. This study evaluates the ecological requirements of the species, and includes a survey of the literature. Although S. lapponica has been reported thus far only in the Northern Hemisphere, the probability of its bipolar distribution is relatively high (22%). Distribution is probably ecologically determined, water temperature (correlated with latitude or seasonal fluctuations), and lower pH seem to be the primary environmental variables. A local vs. global ratio reflects, to a certain extent, the degree of sampling effort expended in the studied area, but a considerable increase in the number of revealed taxa was apparent when the area was expanded.
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Synura obesa sp. nov. (Synurophyceae) and other silica-scaled chrysophytes from Abisko (Swedish Lapland)
Nova Hedwigia, 2008Co-Authors: Yvonne Němcová, Sylvie Nováková, Magda Řezáčová-ŠkaloudováAbstract:Ten taxa of silica-scaled chrysophytes (Synurophyceae and Chrysophyceae) were found during an investigation of mires and peat bogs in the Abisko region (Swedish Lapland). The chrysophyte flora consisted mainly of acidophilic (Synura echinulata, S. sphagnicola, Chrysosphaerella longispina) or pH indifferent widely distributed taxa. Together with frequently reported taxa the rare Synura petersenii f. bjoerkii and a new species of Synura, S. obesa were found. Mallomonas corcontica was reported for the first time from Sweden. The occurrence of the species is discussed in relation to some environmental factors (particularly pH).
James L Wee - One of the best experts on this subject based on the ideXlab platform.
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a reassessment of its 5 8s dna sequence variation and phylogenetic signal in the synurophyceae
Journal of Phycology, 2000Co-Authors: James L WeeAbstract:Previously, DNA sequences were determined for the entire ITS/5.8S region by direct sequencing of PCR amplification products. 28 sequences were obtained from 12 species of Synurophyceae, including Tessellaria volvocina, Chrysodidymus synuroideus, six species of Synura and four species of Mallomonas. Sequences also were determined from multiple strains of some species, including 15 strains of Synura petersenii. The length of these sequences varied from 495–598 bp. The large amount of ITS/5.8S length variation made initial attempts in determining reliable sequence alignment difficult and precluded their use in phylogenetic analyses of the class. Subsequently, the approach of Bogler & Simpson (1996) was investigated where reiterative, computer assisted alignments were generated and the quality of the alignment was evaluated by homoplasy index and consistency index values. However, these alignments also were equivocal. ITS/5.8S sequences sorted the 15 S. petersenii strains into two well supported ITS lineages. One ITS type included ten isolates from North America while isolates from the second ITS type included one each from Germany and Australia and three from North America. Results are presented here where the sequences from the 15 S. petersenii isolates were used to characterize ITS-1 and ITS-2 RNA transcript secondary structure. Next, this information was expanded to include ITS/5.8S sequences from the other taxa in the class. Finally, the characteristics of ITS 1 and ITS 2 RNA transcript secondary structure were used as a guide to align all of the ITS/5.8S sequences from the Synurophyceae in a final phylogenetic analysis.
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PARTIAL CHARACTERIZATION OF THE CHLOROPLAST GENOME FROM THE CHROMOPHYTIC ALGA Synura PETERSENII (SYNUROPHYCEAE)1
Journal of Phycology, 1993Co-Authors: James L Wee, Joby Chesnick, Rose Ann CattolicoAbstract:Hoechst dye 33258-CsCl density gradients were used to isolate two satellite DNA species from Synura petersenii Korsh. sensu lato, a member of the Synurophyceae. One satellite DNA was identified as the chloroplast genome. The chloroplast genome is the smallest (91.5 kb) published for any chromophyte and approximates the size of the smallest functional chlorophyte chloroplast genome (Codium fragile, 89 kb). The second satellite DNA was small (34.5 kb), and its origin is undetermined. The potential of using the S. petersenii chloroplast genome in comparative studies for evaluating organellar evolution and algal systematics is discussed.
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A STATISTICAL CHARACTERIZATION OF GROWTH AMONG CLONES OF Synura PETERSENII (SYNUROPHYCEAE)1
Journal of Phycology, 1991Co-Authors: James L Wee, David F. Millie, Sharon P. WaltonAbstract:Each of four clones from the Synura petersenii complex was grown at different pHs (5.5, 6.5, 7.5, 8.5) in batch culture experiments. Growth response curves and exponential growth rates were compared among clones and pH treatments in order to examine growth trend variation among the clonal groups. The clones were isolated from geographically distant North American localities. The clonal groups represented distinct mating types, an isolate and its subisolate, and S. petersenii- and S. glabra-like scale morphologies. No consistent relationship existed between growth response curve, and culture medium pH. Additionally, the trends across time differed according to clone and pH combination. Pairwise comparisons of linear trends from transformed growth response curves indicated two distinct clonal associations. Although the clonal associations corresponded with the final cell density of the cultures, growth response curves did not correspond with mating type, the parent-isolate and subisolate, or scale morphology. Clones with glabra-like scales had greater growth rates than the clone with petersenii-like scales. The conflicting results generated from growth response curve and growth rate analyses support the concept that S. petersenii and S. glabra form a highly variable, homogeneous grouping.
