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Yang Li - One of the best experts on this subject based on the ideXlab platform.
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diversity in the section compressa of the genus Chaetoceros bacillariophyceae with description of two new species from chinese warm waters
Journal of Phycology, 2019Co-Authors: Xiao Jing Xu, Nina Lundholm, Zuo Yi Chen, Yang LiAbstract:: Monoclonal strains of Chaetoceros species were collected from Chinese warm waters. Vegetative cells and resting spores were examined using light microscopy as well as scanning and transmission electron microscopy. Combined morphological and DNA sequence data from the hypervariable D1-D3 region of the nuclear ribosomal large subunit showed the presence of two new species within the section Compressa, herein described as Chaetoceros bifurcatus sp. nov. and C. millipedarius sp. nov. Both species possessed features typical of the section Compressa, but C. bifurcatus was characterized by the heavy intercalary setae fusing and extending together for a distance before diverging. The heavy setae were not visually contorted, lacking poroids and spines, in contrast with how the section Compressa has been defined. Chaetoceros millipedarius was characterized by a horizontal stagger of ordinary intercalary setae when the chain was seen in broad girdle view, making the chain look like a millipede. The two new species were supported by molecular phylogenetic analyses with C. bifurcatus sister to C. contortus var. ornatus, while C. millipedarius was sister to C. contortus var. contortus. Based on the morphological features exhibited in C. bifurcatus, the diagnosis of the section Compressa was emended to exclude "contorted" heavy setae and compressed valve faces.
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Chaetoceros pauciramosus sp nov bacillariophyceae a widely distributed brackish water species in the c lorenzianus complex
Protist, 2018Co-Authors: Zuo Yi Chen, Ojvind Moestrup, Nina Lundholm, Janina Kownacka, Yang LiAbstract:To understand the diversity of the diatom genus Chaetoceros Ehrenberg, the C. lorenzianus complex was previously chosen as a model and three new species were described. In the present study, yet another new species, Chaetoceros pauciramosus sp. nov., was discovered from Chinese tropical waters and the temperate south-eastern Baltic Sea. In the latter locality it has been known since 2003 and identified as C. cf lorenzianus, and now found to comprise a dominating component of the autumn phytoplankton community. Vegetative cells and resting spores were examined by light and electron microscopy. The LSU and SSU of the nuclear rDNA were sequenced. The characters suggesting that C. pauciramosus belongs to C. lorenzianus complex are: 1) the vegetative cells contain four or more chloroplasts, 2) the cells have stiff setae and form regular straight chains, 3) the terminal setae differ in the direction from the intercalary setae. The relationship was well-supported by molecular phylogenetic analyses inferred from both LSU and SSU markers. The primary valve of the resting spore has two conical elevations, each with dichotomously branching processes, similar to other species in the C. lorenzianus complex. Each process forms a tree-like structure with the pointed distal tips which possess one or two thin spikes, that distinguishes C. pauciramosus from allied taxa. In the phylogenetic trees, Chaetoceros pauciramosus clustered with C. elegans, in agreement with their morphologically similar resting spores.
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morphology and molecular phylogeny of Chaetoceros dayaensis sp nov bacillariophyceae characterized by two 90 rotations of the resting spore during maturation
Journal of Phycology, 2015Co-Authors: Yang Li, Nina Lundholm, Songhui LuAbstract:: Recent studies suggest that a high species diversity of Chaetoceros exists in tropical waters. Based on plankton samples from Chinese tropical waters, Daya Bay of the South China Sea, a new species, Chaetoceros dayaensis sp. nov., is described. Vegetative cells and resting spores were examined by light microscopy as well as transmission and scanning electron microscopy. The nuclear rDNA molecular markers SSU, ITS and D1-D3 of LSU, and the chloroplast rbcL gene were sequenced for information on phylogenetic relationships. The species is characterized by the presence of two 90° rotations of the resting spore during maturation. First a rotation in the apical plane of the mother cell resulting in the valvar plane of the resting spore turning from parallel to perpendicular to that of the mother cell, and a second 90° rotation in the valvar plane of the mother cell resulting in the valve faces of the resting spore turning from facing narrow girdle view to broad girdle view of the mother cell. It is the first report of two 90° rotations of resting spores during maturation in Chaetoceros. Based on this, the maturation rotation of the resting spore of C. rotosporus was reevaluated. C. dayaensis belongs to the subgenus Hyalochaete Gran and we suggest placing it in the section Laciniosa, although a new subdivision of Chaetoceros is needed. The description of C. dayaensis was based on analyses of the phylogenetic relationships combined with morphological comparisons with other similar species.
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Chaetoceros rotosporus sp nov bacillariophyceae a species with unusual resting spore formation
Phycologia, 2013Co-Authors: Yang Li, Nina Lundholm, Ojvind MoestrupAbstract:Li Y., Lundholm N. and Moestrup O. 2013. Chaetoceros rotosporus sp. nov. (Bacillariophyceae), a species with unusual resting spore formation. Phycologia 52: 600–608. DOI: 10.2216/13-168.1With more ...
Nina Lundholm - One of the best experts on this subject based on the ideXlab platform.
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diversity in the section compressa of the genus Chaetoceros bacillariophyceae with description of two new species from chinese warm waters
Journal of Phycology, 2019Co-Authors: Xiao Jing Xu, Nina Lundholm, Zuo Yi Chen, Yang LiAbstract:: Monoclonal strains of Chaetoceros species were collected from Chinese warm waters. Vegetative cells and resting spores were examined using light microscopy as well as scanning and transmission electron microscopy. Combined morphological and DNA sequence data from the hypervariable D1-D3 region of the nuclear ribosomal large subunit showed the presence of two new species within the section Compressa, herein described as Chaetoceros bifurcatus sp. nov. and C. millipedarius sp. nov. Both species possessed features typical of the section Compressa, but C. bifurcatus was characterized by the heavy intercalary setae fusing and extending together for a distance before diverging. The heavy setae were not visually contorted, lacking poroids and spines, in contrast with how the section Compressa has been defined. Chaetoceros millipedarius was characterized by a horizontal stagger of ordinary intercalary setae when the chain was seen in broad girdle view, making the chain look like a millipede. The two new species were supported by molecular phylogenetic analyses with C. bifurcatus sister to C. contortus var. ornatus, while C. millipedarius was sister to C. contortus var. contortus. Based on the morphological features exhibited in C. bifurcatus, the diagnosis of the section Compressa was emended to exclude "contorted" heavy setae and compressed valve faces.
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Chaetoceros pauciramosus sp nov bacillariophyceae a widely distributed brackish water species in the c lorenzianus complex
Protist, 2018Co-Authors: Zuo Yi Chen, Ojvind Moestrup, Nina Lundholm, Janina Kownacka, Yang LiAbstract:To understand the diversity of the diatom genus Chaetoceros Ehrenberg, the C. lorenzianus complex was previously chosen as a model and three new species were described. In the present study, yet another new species, Chaetoceros pauciramosus sp. nov., was discovered from Chinese tropical waters and the temperate south-eastern Baltic Sea. In the latter locality it has been known since 2003 and identified as C. cf lorenzianus, and now found to comprise a dominating component of the autumn phytoplankton community. Vegetative cells and resting spores were examined by light and electron microscopy. The LSU and SSU of the nuclear rDNA were sequenced. The characters suggesting that C. pauciramosus belongs to C. lorenzianus complex are: 1) the vegetative cells contain four or more chloroplasts, 2) the cells have stiff setae and form regular straight chains, 3) the terminal setae differ in the direction from the intercalary setae. The relationship was well-supported by molecular phylogenetic analyses inferred from both LSU and SSU markers. The primary valve of the resting spore has two conical elevations, each with dichotomously branching processes, similar to other species in the C. lorenzianus complex. Each process forms a tree-like structure with the pointed distal tips which possess one or two thin spikes, that distinguishes C. pauciramosus from allied taxa. In the phylogenetic trees, Chaetoceros pauciramosus clustered with C. elegans, in agreement with their morphologically similar resting spores.
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morphology and molecular phylogeny of Chaetoceros dayaensis sp nov bacillariophyceae characterized by two 90 rotations of the resting spore during maturation
Journal of Phycology, 2015Co-Authors: Yang Li, Nina Lundholm, Songhui LuAbstract:: Recent studies suggest that a high species diversity of Chaetoceros exists in tropical waters. Based on plankton samples from Chinese tropical waters, Daya Bay of the South China Sea, a new species, Chaetoceros dayaensis sp. nov., is described. Vegetative cells and resting spores were examined by light microscopy as well as transmission and scanning electron microscopy. The nuclear rDNA molecular markers SSU, ITS and D1-D3 of LSU, and the chloroplast rbcL gene were sequenced for information on phylogenetic relationships. The species is characterized by the presence of two 90° rotations of the resting spore during maturation. First a rotation in the apical plane of the mother cell resulting in the valvar plane of the resting spore turning from parallel to perpendicular to that of the mother cell, and a second 90° rotation in the valvar plane of the mother cell resulting in the valve faces of the resting spore turning from facing narrow girdle view to broad girdle view of the mother cell. It is the first report of two 90° rotations of resting spores during maturation in Chaetoceros. Based on this, the maturation rotation of the resting spore of C. rotosporus was reevaluated. C. dayaensis belongs to the subgenus Hyalochaete Gran and we suggest placing it in the section Laciniosa, although a new subdivision of Chaetoceros is needed. The description of C. dayaensis was based on analyses of the phylogenetic relationships combined with morphological comparisons with other similar species.
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diversity of the marine diatom Chaetoceros bacillariophyceae in thai waters revisiting Chaetoceros compressus and Chaetoceros contortus
Phycologia, 2015Co-Authors: Atchaneey Chamnansinp, Ojvind Moestrup, Nina LundholmAbstract:Abstract Chaetoceros is one of the most species-rich phytoplankton genera, and its known diversity can be expected to increase significantly when additional material from tropical and other less studied areas has been examined by a combination of molecular and morphological methods. We have succeeded in culturing and examining a pair of very characteristic Chaetoceros species, Chaetoceros compressus and Chaetoceros contortus, from a number of geographically separate localities. The pair is easily recognizable as such because of the heavy setae characteristic of the section Compressa but morphological similarities between the two species have caused considerable taxonomic confusion since the second species, C. contortus, was described nearly one hundred years ago. Critical studies exploring species delineation are therefore needed to determine whether C. compressus and C. contortus should be considered separate species. A combination of phylogenetic analyses based on large subunit rDNA and detailed morphol...
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Chaetoceros rotosporus sp nov bacillariophyceae a species with unusual resting spore formation
Phycologia, 2013Co-Authors: Yang Li, Nina Lundholm, Ojvind MoestrupAbstract:Li Y., Lundholm N. and Moestrup O. 2013. Chaetoceros rotosporus sp. nov. (Bacillariophyceae), a species with unusual resting spore formation. Phycologia 52: 600–608. DOI: 10.2216/13-168.1With more ...
D W Coats - One of the best experts on this subject based on the ideXlab platform.
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isolation and preliminary characterisation of a small nuclear inclusion virus infecting the diatom Chaetoceros cf gracilis
Aquatic Microbial Ecology, 2005Co-Authors: Yvan Bettarel, Kui Wang, Kurt E Williamson, S Cooney, S Ribblett, Feng Chen, K E Wommack, D W CoatsAbstract:A novel virus (Chaetoceros nuclear inclusion virus: CspNIV) causing lysis of a culture of the diatom Chaetoceros cf. gracilis was isolated from the Chesapeake Bay, USA, in April 2003. Trans- mission electron microscopy of ultrathin sections of infected C. cf. gracilis revealed that CspNIV pro- liferates within the nucleus and forms paracrystalline arrays corresponding to the alignment of icosahedral viral particles of about 25 nm diameter. CspNIV shows some strong similarities with Heterosigma akashiwo nuclear inclusion virus (HaNIV) (cf. Lawrence et al. 2001; J Phycol 37: 216-222). The latent period of CspNIV is <24 h. The most widespread occurrence of Chaetoceros viruses in Chesapeake Bay was recorded in April 2003, ca. 1 mo after the winter-spring Chaetoceros bloom. However, results indicate that CspNIV remains infectious in surface water of the bay no longer than 1 mo after the disappearance of its host. Thus, our results reinforce the idea that microalgae are also sensitive to viruses other than those belonging to the family Phycodnaviridae. Furthermore, dis- covery and initial description of the infection process and ecology of CspNIV expands the breadth of phytoplankton shown to be susceptible to viral attack to include a ubiquitous diatom genera.
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Isolation and preliminary characterisation of a small nuclear inclusion virus infecting the diatom Chaetoceros cf. gracilis
Aquatic Microbial Ecology, 2005Co-Authors: Yvan Bettarel, Kui Wang, Kurt E Williamson, S Cooney, S Ribblett, Feng Chen, K E Wommack, D W CoatsAbstract:A novel virus (Chaetoceros nuclear inclusion virus: CspNIV) causing lysis of a culture of the diatom Chaetoceros cf. gracilis was isolated from the Chesapeake Bay, USA, in April 2003. Trans- mission electron microscopy of ultrathin sections of infected C. cf. gracilis revealed that CspNIV pro- liferates within the nucleus and forms paracrystalline arrays corresponding to the alignment of icosahedral viral particles of about 25 nm diameter. CspNIV shows some strong similarities with Heterosigma akashiwo nuclear inclusion virus (HaNIV) (cf. Lawrence et al. 2001; J Phycol 37: 216-222). The latent period of CspNIV is
Ojvind Moestrup - One of the best experts on this subject based on the ideXlab platform.
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Chaetoceros pauciramosus sp nov bacillariophyceae a widely distributed brackish water species in the c lorenzianus complex
Protist, 2018Co-Authors: Zuo Yi Chen, Ojvind Moestrup, Nina Lundholm, Janina Kownacka, Yang LiAbstract:To understand the diversity of the diatom genus Chaetoceros Ehrenberg, the C. lorenzianus complex was previously chosen as a model and three new species were described. In the present study, yet another new species, Chaetoceros pauciramosus sp. nov., was discovered from Chinese tropical waters and the temperate south-eastern Baltic Sea. In the latter locality it has been known since 2003 and identified as C. cf lorenzianus, and now found to comprise a dominating component of the autumn phytoplankton community. Vegetative cells and resting spores were examined by light and electron microscopy. The LSU and SSU of the nuclear rDNA were sequenced. The characters suggesting that C. pauciramosus belongs to C. lorenzianus complex are: 1) the vegetative cells contain four or more chloroplasts, 2) the cells have stiff setae and form regular straight chains, 3) the terminal setae differ in the direction from the intercalary setae. The relationship was well-supported by molecular phylogenetic analyses inferred from both LSU and SSU markers. The primary valve of the resting spore has two conical elevations, each with dichotomously branching processes, similar to other species in the C. lorenzianus complex. Each process forms a tree-like structure with the pointed distal tips which possess one or two thin spikes, that distinguishes C. pauciramosus from allied taxa. In the phylogenetic trees, Chaetoceros pauciramosus clustered with C. elegans, in agreement with their morphologically similar resting spores.
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diversity of the marine diatom Chaetoceros bacillariophyceae in thai waters revisiting Chaetoceros compressus and Chaetoceros contortus
Phycologia, 2015Co-Authors: Atchaneey Chamnansinp, Ojvind Moestrup, Nina LundholmAbstract:Abstract Chaetoceros is one of the most species-rich phytoplankton genera, and its known diversity can be expected to increase significantly when additional material from tropical and other less studied areas has been examined by a combination of molecular and morphological methods. We have succeeded in culturing and examining a pair of very characteristic Chaetoceros species, Chaetoceros compressus and Chaetoceros contortus, from a number of geographically separate localities. The pair is easily recognizable as such because of the heavy setae characteristic of the section Compressa but morphological similarities between the two species have caused considerable taxonomic confusion since the second species, C. contortus, was described nearly one hundred years ago. Critical studies exploring species delineation are therefore needed to determine whether C. compressus and C. contortus should be considered separate species. A combination of phylogenetic analyses based on large subunit rDNA and detailed morphol...
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Chaetoceros rotosporus sp nov bacillariophyceae a species with unusual resting spore formation
Phycologia, 2013Co-Authors: Yang Li, Nina Lundholm, Ojvind MoestrupAbstract:Li Y., Lundholm N. and Moestrup O. 2013. Chaetoceros rotosporus sp. nov. (Bacillariophyceae), a species with unusual resting spore formation. Phycologia 52: 600–608. DOI: 10.2216/13-168.1With more ...
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The genus Chaetoceros (Bacillariophyceae) in inner Danish coastal waters
Nordic Journal of Botany, 1998Co-Authors: Karin G. Jensen, Ojvind MoestrupAbstract:The genus Chaetoceros, one of the most important genera of diatoms in the marine plankton, has been investigated from 20 stations in Danish waters during the period 1991–1995. Thirty-five taxa were identified, 18 of which were brought into culture for further morphological studies. Three taxa are reported for the first time from Danish coastal waters and one new species is proposed, C. impressus. Chaetoceros affinis var. circinalis is raised to species level. Material referred to previously as Chaetoceros sp. B. by Sundstrom is considered to represent C. pseudobrevis. Twelve taxa found previously in the area by other authors are also described, resulting in a total of 47 descriptions. An artificial key is provided for identifications of all species presently recorded in inner Danish coastal waters.
Yvan Bettarel - One of the best experts on this subject based on the ideXlab platform.
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isolation and preliminary characterisation of a small nuclear inclusion virus infecting the diatom Chaetoceros cf gracilis
Aquatic Microbial Ecology, 2005Co-Authors: Yvan Bettarel, Kui Wang, Kurt E Williamson, S Cooney, S Ribblett, Feng Chen, K E Wommack, D W CoatsAbstract:A novel virus (Chaetoceros nuclear inclusion virus: CspNIV) causing lysis of a culture of the diatom Chaetoceros cf. gracilis was isolated from the Chesapeake Bay, USA, in April 2003. Trans- mission electron microscopy of ultrathin sections of infected C. cf. gracilis revealed that CspNIV pro- liferates within the nucleus and forms paracrystalline arrays corresponding to the alignment of icosahedral viral particles of about 25 nm diameter. CspNIV shows some strong similarities with Heterosigma akashiwo nuclear inclusion virus (HaNIV) (cf. Lawrence et al. 2001; J Phycol 37: 216-222). The latent period of CspNIV is <24 h. The most widespread occurrence of Chaetoceros viruses in Chesapeake Bay was recorded in April 2003, ca. 1 mo after the winter-spring Chaetoceros bloom. However, results indicate that CspNIV remains infectious in surface water of the bay no longer than 1 mo after the disappearance of its host. Thus, our results reinforce the idea that microalgae are also sensitive to viruses other than those belonging to the family Phycodnaviridae. Furthermore, dis- covery and initial description of the infection process and ecology of CspNIV expands the breadth of phytoplankton shown to be susceptible to viral attack to include a ubiquitous diatom genera.
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Isolation and preliminary characterisation of a small nuclear inclusion virus infecting the diatom Chaetoceros cf. gracilis
Aquatic Microbial Ecology, 2005Co-Authors: Yvan Bettarel, Kui Wang, Kurt E Williamson, S Cooney, S Ribblett, Feng Chen, K E Wommack, D W CoatsAbstract:A novel virus (Chaetoceros nuclear inclusion virus: CspNIV) causing lysis of a culture of the diatom Chaetoceros cf. gracilis was isolated from the Chesapeake Bay, USA, in April 2003. Trans- mission electron microscopy of ultrathin sections of infected C. cf. gracilis revealed that CspNIV pro- liferates within the nucleus and forms paracrystalline arrays corresponding to the alignment of icosahedral viral particles of about 25 nm diameter. CspNIV shows some strong similarities with Heterosigma akashiwo nuclear inclusion virus (HaNIV) (cf. Lawrence et al. 2001; J Phycol 37: 216-222). The latent period of CspNIV is