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Richard M. Mccourt - One of the best experts on this subject based on the ideXlab platform.
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PHYLOGENY OF THE CONJUGATING GREEN ALGAE (Zygnemophyceae) BASED ON rbc L SEQUENCES
Journal of Phycology, 2000Co-Authors: Richard M. Mccourt, Jeremy Bell, Kathleen Helm-bychowski, Anna Grajewska, Kenneth G. Karol, Martin F Wojciechowski, Robert W HoshawAbstract:Sequences of the gene encoding the large subunit of RUBISCO (rbcL) for 30 genera in the six currently recognized families of conjugating green algae (Desmidiaceae, Gonatozygaceae, Mesotaeniaceae, Peniaceae, and Zygnemataceae) were analyzed using maximum parsimony and maximum likelihood; bootstrap replications were performed as a measure of support for clades. Other Charophyceae sensu Mattox and Stewart and representative land plants were used as outgroups. All analyses supported the monophyly of the conjugating green algae. The Desmidiales, or placoderm desmids, constitute a monophyletic group, with moderate to strong support for the four component families of this assemblage (Closteriaceae, Desmidiaceae, Gonatozygaceae, and Peniaceae). The analyses showed that the two families of Zygnematales (Mesotaeniaceae, Zygnemataceae), which have plesiomorphic, unornamented and unsegmented cell walls, are not monophyletic. However, combined taxa of these two traditional families may constitute a monophyletic group. Partitioning the data by codon position revealed no significant differences across all positions or between partitions of positions one and two versus position three. The trees resulting from parsimony analyses using first plus second positions versus third position differed only in topology of branches with poor bootstrap support. The tree derived from third positions only was more resolved than the tree derived from first and second positions. The rbcL-based phylogeny is largely congruent with published analyses of small subunit rDNA sequences for the Zygnematales. The molecular data do not support hypotheses of monophyly for groups of extant unicellular and filamentous or colonial desmid genera exhibiting a common cell shape. A trend is evident from simple omniradiate cell shapes to taxa with lobed cell and plastid shapes, which supports the hypothesis that chloroplast shape evolved generally from simple to complex. The data imply that multicellular placoderm desmids are monophyletic. Several anomalous placements of genera were found, including the saccoderm desmid Roya in the Gonatozygaceae and the zygnematacean Entransia in the Coleochaetales. The former is strongly supported, although the latter is not, and Entransia's phylogenetic position warrants further study.
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PHYLOGENY OF THE BASAL LINEAGES OF STREPTOPHYTA BASED ON RBCL AND ATPB GENE SEQUENCE DATA
Journal of Phycology, 2000Co-Authors: Kenneth G. Karol, Charles F. Delwiche, Richard M. MccourtAbstract:The streptophytes comprise the Charophyceae sensu Mattox and Stewart (a morphologically diverse group of fresh-water green algae) and the embryophytes (land plants). Several charophycean groups are currently recognized. These include the Charales, Coleochaetales, Chlorokybales, Klebsormidiales and Zygnemophyceae (Desmidiales and Zygnematales). Recently, SSU rRNA gene sequence data allied Mesostigma viride (Prasinophyceae) with the Streptophyta. Complete chloroplast sequence data, however, placed Mesostigma sister to all green algae, not with the streptophytes. Several morphological, ultrastructural and biochemical features unite these lineages into a monophyletic group including embryophytes, but evolutionary relationships among the basal streptophytes remain ambiguous. To date, numerous studies using SSU rRNA gene sequences have yielded differing phylogenies with varying degrees of support dependent upon taxon sampling and choice of phylogenetic method. Like SSU data, chloroplast DNA sequence data have been used to examine relationships within the Charales, Coleochaetales, Zygnemophyceae and embryophytes. Representatives of all basal streptophyte lineages have not been examined using chloroplast data in a single analysis. Phylogenetic analyses were performed using DNA sequences of rbcL (the genes encoding the large subunit of rubisco) and atpB (the beta-subunit of ATPase) to examine relationships of basal streptophyte lineages. Preliminary analyses placed the branch leading to Mesostigma as the basal lineage in the Streptophyta with Chlorokybus, the sole representative of the Chlorokybales, branching next. Klebsormidiales and the enigmatic genus Entransia were sister taxa. Sister to these, the Charales, Coleochaetales, embryophytes and Zygnemophyceae formed a monophyletic group with Charales and Coleochaetales sister to each other and this clade sister to the embryophytes.
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PHYLOGENY OF Zygnemophyceae BASED ON COXIII GENE SEQUENCE DATA
Journal of Phycology, 2000Co-Authors: D. Hewitt, Kenneth G. Karol, Richard M. MccourtAbstract:Molecular phylogenetic analysis of the conjugating green algae (Class Zygnemophyceae) using nuclear (SSU rDNA) and chloroplast (rbcL) gene sequences has resolved hypotheses of relationship at the class, order, and family levels, but several key questions will require data from additional genes. Based on SSU and rbcL sequences, the Zygnemophyceae and Desmidiales are monophyletic, and families of placoderm desmids are distinct clades (Desmidiaceae, Peniaceae, Closteriaceae, and Gonatozygaceae). In contrast, the Zygnemataceae and Mesotaeniaceae are paraphyletic, although whether these two traditional families constitute a clade is uncertain. In addition, relationships of genera within families have proven resistant to resolution with these two oft-used genes. We have sequenced the coxIII gene from the mitochondrial genome to address some of these ambiguous portions of the phylogeny of conjugating green algae. The coxIII gene is more variable than rbcL or SSU rDNA and offers greater resolving power for relationships of genera. We present preliminary analyses of coxIII sequences from each of the traditional families of Zygnemophyceae and contrast the resulting topologies with those derived from nuclear and chloroplast genes.
Kenneth G. Karol - One of the best experts on this subject based on the ideXlab platform.
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PHYLOGENY OF THE CONJUGATING GREEN ALGAE (Zygnemophyceae) BASED ON rbc L SEQUENCES
Journal of Phycology, 2000Co-Authors: Richard M. Mccourt, Jeremy Bell, Kathleen Helm-bychowski, Anna Grajewska, Kenneth G. Karol, Martin F Wojciechowski, Robert W HoshawAbstract:Sequences of the gene encoding the large subunit of RUBISCO (rbcL) for 30 genera in the six currently recognized families of conjugating green algae (Desmidiaceae, Gonatozygaceae, Mesotaeniaceae, Peniaceae, and Zygnemataceae) were analyzed using maximum parsimony and maximum likelihood; bootstrap replications were performed as a measure of support for clades. Other Charophyceae sensu Mattox and Stewart and representative land plants were used as outgroups. All analyses supported the monophyly of the conjugating green algae. The Desmidiales, or placoderm desmids, constitute a monophyletic group, with moderate to strong support for the four component families of this assemblage (Closteriaceae, Desmidiaceae, Gonatozygaceae, and Peniaceae). The analyses showed that the two families of Zygnematales (Mesotaeniaceae, Zygnemataceae), which have plesiomorphic, unornamented and unsegmented cell walls, are not monophyletic. However, combined taxa of these two traditional families may constitute a monophyletic group. Partitioning the data by codon position revealed no significant differences across all positions or between partitions of positions one and two versus position three. The trees resulting from parsimony analyses using first plus second positions versus third position differed only in topology of branches with poor bootstrap support. The tree derived from third positions only was more resolved than the tree derived from first and second positions. The rbcL-based phylogeny is largely congruent with published analyses of small subunit rDNA sequences for the Zygnematales. The molecular data do not support hypotheses of monophyly for groups of extant unicellular and filamentous or colonial desmid genera exhibiting a common cell shape. A trend is evident from simple omniradiate cell shapes to taxa with lobed cell and plastid shapes, which supports the hypothesis that chloroplast shape evolved generally from simple to complex. The data imply that multicellular placoderm desmids are monophyletic. Several anomalous placements of genera were found, including the saccoderm desmid Roya in the Gonatozygaceae and the zygnematacean Entransia in the Coleochaetales. The former is strongly supported, although the latter is not, and Entransia's phylogenetic position warrants further study.
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PHYLOGENY OF THE BASAL LINEAGES OF STREPTOPHYTA BASED ON RBCL AND ATPB GENE SEQUENCE DATA
Journal of Phycology, 2000Co-Authors: Kenneth G. Karol, Charles F. Delwiche, Richard M. MccourtAbstract:The streptophytes comprise the Charophyceae sensu Mattox and Stewart (a morphologically diverse group of fresh-water green algae) and the embryophytes (land plants). Several charophycean groups are currently recognized. These include the Charales, Coleochaetales, Chlorokybales, Klebsormidiales and Zygnemophyceae (Desmidiales and Zygnematales). Recently, SSU rRNA gene sequence data allied Mesostigma viride (Prasinophyceae) with the Streptophyta. Complete chloroplast sequence data, however, placed Mesostigma sister to all green algae, not with the streptophytes. Several morphological, ultrastructural and biochemical features unite these lineages into a monophyletic group including embryophytes, but evolutionary relationships among the basal streptophytes remain ambiguous. To date, numerous studies using SSU rRNA gene sequences have yielded differing phylogenies with varying degrees of support dependent upon taxon sampling and choice of phylogenetic method. Like SSU data, chloroplast DNA sequence data have been used to examine relationships within the Charales, Coleochaetales, Zygnemophyceae and embryophytes. Representatives of all basal streptophyte lineages have not been examined using chloroplast data in a single analysis. Phylogenetic analyses were performed using DNA sequences of rbcL (the genes encoding the large subunit of rubisco) and atpB (the beta-subunit of ATPase) to examine relationships of basal streptophyte lineages. Preliminary analyses placed the branch leading to Mesostigma as the basal lineage in the Streptophyta with Chlorokybus, the sole representative of the Chlorokybales, branching next. Klebsormidiales and the enigmatic genus Entransia were sister taxa. Sister to these, the Charales, Coleochaetales, embryophytes and Zygnemophyceae formed a monophyletic group with Charales and Coleochaetales sister to each other and this clade sister to the embryophytes.
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PHYLOGENY OF Zygnemophyceae BASED ON COXIII GENE SEQUENCE DATA
Journal of Phycology, 2000Co-Authors: D. Hewitt, Kenneth G. Karol, Richard M. MccourtAbstract:Molecular phylogenetic analysis of the conjugating green algae (Class Zygnemophyceae) using nuclear (SSU rDNA) and chloroplast (rbcL) gene sequences has resolved hypotheses of relationship at the class, order, and family levels, but several key questions will require data from additional genes. Based on SSU and rbcL sequences, the Zygnemophyceae and Desmidiales are monophyletic, and families of placoderm desmids are distinct clades (Desmidiaceae, Peniaceae, Closteriaceae, and Gonatozygaceae). In contrast, the Zygnemataceae and Mesotaeniaceae are paraphyletic, although whether these two traditional families constitute a clade is uncertain. In addition, relationships of genera within families have proven resistant to resolution with these two oft-used genes. We have sequenced the coxIII gene from the mitochondrial genome to address some of these ambiguous portions of the phylogeny of conjugating green algae. The coxIII gene is more variable than rbcL or SSU rDNA and offers greater resolving power for relationships of genera. We present preliminary analyses of coxIII sequences from each of the traditional families of Zygnemophyceae and contrast the resulting topologies with those derived from nuclear and chloroplast genes.
Okmin Lee - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic study of genera staurastrum and staurodesmus Zygnemophyceae streptophyta inferred from atpb sequences
Algae, 2005Co-Authors: Byeongryeol Moo, Ansuk Lim, Jaehyun Ahn, Junghoon Park, Okmin LeeAbstract:We analyzed chloroplast ATP synthetase beta subunit(atpB) sequences from 32 strains of the zygnemophycean green algae, Staurastrum, Staurodesmus, and a single species of Xanthidium. A total of 42 atpB sequences including previously published ones was aligned for phylogenetic analyses. The phylogenies were validated with bootstrap analysis and Kishino-Hasegawa test. Taxa of Staurastrum excluding S. muticum indicate that they can be characterized by taxa having the ornamented cell wall or the process of cells. However, the genus Staurodesmus was grouped with taxa having the smooth cell wall and the absence of process or arms. The results suggest that the genus Staurodesmus could be extended to include Staurastrum muticum, Desmidium, Onychonema and Xanthidium. Further taxon sampling of Staurodesmus and putative relatives is necessary for a solid classification of the genus.
Mustafa Shameel - One of the best experts on this subject based on the ideXlab platform.
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TAXONOMIC STUDIES OF THE CLASS Zygnemophyceae SHAMEEL FROM NORTH-EASTERN AREAS OF PAKISTAN
2008Co-Authors: A. Zarina, Mustafa ShameelAbstract:Five species of the algal genera, Hallasia Rosenvinge and Mougeotia C. A. Agardh have been collected from various freshwater habitats of Kasur, Lahore, Sargodha and Sialkot districts of Punjab Province of Pakistan and Neelum Valley of Azad Kashmir during March and October 2004 and taxonomically investigated. Although, all the species have been described for the first time from their area of collection, most of them are first reports from Pakistan. They were mostly found in spring.
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diversity of the genus spirogyra Zygnemophyceae shameel in the north eastern areas of pakistan
2007Co-Authors: A. Zarina, Mustafa ShameelAbstract:Forty-two species of the genus Spirogyra Link (Chlorophyta) were collected from various freshwater habitats in Gujranwala, Jhang, Kasur, Lahore, Sheikhupura and Sialkot and Attock Districts of the Punjab Province and Swat of N. W. F. Province as well as Chenari and Neelum Valley of Azad Kashmir during January 2004 and April 2005. They were taxonomically investigated and have been described for the first time from their area of collection. Out of these, 22 species are being reported for the first time from any area of Pakistan. They thrived luxuriantly during winter and spring seasons, started diminishing in summer and disappeared to a great extent in autumn.
Madhvi Gaind - One of the best experts on this subject based on the ideXlab platform.
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Morpho-Taxonomic Studies on the Genus Spirogyra Link (Cholorophyta) Occuring in Fresh Water Bodies of Jammu, Jammu And Kashmir
IOSR Journal of Agriculture and Veterinary Science, 2013Co-Authors: Priyanka Chalotra, Madhvi GaindAbstract:Sixteen species of Spirogyra Link 1820 (Zygnemophyceae, Chlorophyceae) were collected during 2008 to 2010 from different freshwater habitats of three districts of Jammu province viz., Samba district, Jammu district and Udhampur district. They were taxonomically determined on the basis of vegetative structure and reproductive structure. Their reproduction was mostly studied during winters and spring seasons. Both lateral conjugation and scalar form conjugation were observed. The scalariform conjugation was most common type of conjugation method among species. S. calcarea, S rectispire, S submarina, S hollandiae and S buchetii were taxonomically determined and have been described for first time in India and Jammu. Their reproduction was observed to occur mostly in winter and spring season. All sixteen species were found abundantly in both lentic and lotic water habitat.
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Morpho-Taxonomic studies on the Genus Zygnema Agardh (Cholorophyta) Occuring in fresh water bodies of Jammu, Jammu and Kashmir
2013Co-Authors: Priyanka Chalotra, Madhvi Gaind, Vijay Kumar AnandAbstract:ourteen species of Zygnema Agardh 1824 (Zygnemophyceae, Chlorophyceae) were collected during 2008 to 2010 from different freshwater habitats of three districts of Jammu province viz., Samba district, Jammu district and Udhampur district. They were taxonomically determined on the basis of vegetative structure and reproductive structure. Their reproduction was mostly studied during winters and spring seasons. Both lateral conjugation and scalariform conjugation were observed. The scalariform conjugation was most common type of conjugation method among species. Z. ornatum, Z. leuteosporum, Z. leiospermum, Z. stagnale, Z. oveidanum, Z. sterile, Z. ellpsoideum, Z. spontaneum, Z. mirificum and Z. frgidum were taxonomically determined and have been described for first time in India and Jammu. Their reproduction was observed to occur mostly in winter and spring season. All fouteen species were found abundantly in both lentic and lotic water habitat.