Harmful algal blooms often occurred in the East China Sea （ECS） and the German coastal waters of the North Sea but Karlodinium veneficum had not been taxonomically reported. Two strains of Karlodinium （LAMB090611 a...Harmful algal blooms often occurred in the East China Sea （ECS） and the German coastal waters of the North Sea but Karlodinium veneficum had not been taxonomically reported. Two strains of Karlodinium （LAMB090611 and LAMB010601） were isolated from the two areas in 2009. The morphological characteristics and molecular phylogeny of two strains are compared on the basis of observation of a light microscope, a scanning electron microscope （SEM）, a laser scanning micro-scope （LSM） and an internal transcribed spacer （ITS） sequence data. The mean cell length of strain LAMB090611 is （14.2 ± 1.8） μm （range 11.1–18.7 μm） and mean width is （10.8 ± 1.5） μm （range 8.2– 14.7 μm）. The mean cell length of strain LAMB010601 is （15.1 ± 1.2） μm （range 12.7–17.9 μm） and the mean width is （11.4 ± 1.1） μm （range 9.1–14.7 μm）, respectively. The two strains are similar in morphological characteristics, including a straight apical groove, distinct ventral pore, sulcal extension, cingulum displacement, two or four irregular shaped chloroplasts within the cell and almost equal sized epicone and hypocone. The large and round nucleus is located at the center or at the hypocone of the cell. The sequence length of the ECS strain LAMB090611 and the German strain LAMB010601 is 640 and 646 bp, respectively. The GC content is 49%. The nucleotide similarity of the two strains is 98.1%. The sequence divergence is 0.003. Both strains are confirmed as Karlo-dinium veneficum （D. Ballantine） J. Larsen and this is the first taxonomic report from China and Germany coastal waters. The population dynamics of this toxic species in the ECS and German coastal waters needs to be investigated in the near future.展开更多
Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were ...Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were set up from seawater samples taken during the bloom.The cultures were examined for morphological features,ultrastructure characters,photosynthetic pigments,the large subunit(LSU)of the rRNA gene,and the internal transcribed spacer(ITS)sequences,as well as acute toxicity analysis.The cell was unarmored,small-sized,and ovoid,and was characterized by elaborate striations on the epicone and hypocone.The nucleus was large,ellipsoid to oval or kidney-shaped,and centrally located in the cell.A long linear apical groove originated above the sulcus in the ventral epicone and extended to the dorsal side.An elongate,slit-like“ventral pore”was located on the left of the epicone,well away from the apical groove.The chloroplasts were yellowish brown,numerous,band like,and irregularly distributed in the cell periphery.Fucoxanthin was the main accessory pigment composition.Phylogeny topology reconstructed on partial LSU rDNA showed that the unknown dinofl agellate branched as a sister species to Karlodinium sp.(strain IFR981&IFR797,from France)and Karlodinium corrugatum(strain KDGSO08,from Australia),with genetic divergences of 0.6%and 3.3%,respectively.Based on the morphological and molecular phylogenetic analysis,we describe the novel dinofl agellate as Karlodinium elegans sp.nov.A toxicity assay revealed that the clonal culture of K.elegans(strain PTB601)had no adverse eff ect on brine shrimp(Artemia salina)and marine medaka(Oryzias melastigma),indicating it may not be a toxic species.展开更多
On May 24-29,2019,a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish(Plectorhinchus cinctus and Pagrosomus major).During the bloom,two major causative organisms w...On May 24-29,2019,a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish(Plectorhinchus cinctus and Pagrosomus major).During the bloom,two major causative organisms were present:Prorocentrum donghaiense(at a concentration of 1.46×10^7 cells/L)and an unknown naked dinoflagellate(4.58×10^6 cells/L).The naked dinoflagellate was isolated and cultured in this study,and its morphological features were examined using light microscopy and scanning electron microscopy.The large subunit(LSU)of the rRNA gene and the internal transcribed spacer(ITS)region of the naked dinoflagellate were also sequenced for field bloom samples and lab culture strains(PT-A and PT-B).On the basis of its morphological characteristics and molecular sequences,the unknown naked dinoflagellate was identified as Karlodinium digitatum.According to the phylogenetic analysis,the Karl.digitatum was most closely related to Karlodinium australe and Karlodinium armiger,and the three species clustered into a single clade of Karlodinium with bootstrap/posterior probability values of 95%/0.99 and 86%/0.99 inferred from LSU and ITS sequences,respectively.Karl.digitatum was first reported as Karenia digitata,a new harmful algal species bloomed in Hong Kong,China,in 1998.In present study,we gave a detailed morphological and phylogenetic description of Karl.digitatum and submitted the molecular sequences of this species to GenBank for the first time.展开更多
Typical harmful micro-algal species constantly occurred in high density in marine aquaculture ponds in Xiangshan and Sanmen Bay, Zhejiang Province. Fates of the microalgal cells influenced by activity of the cultured ...Typical harmful micro-algal species constantly occurred in high density in marine aquaculture ponds in Xiangshan and Sanmen Bay, Zhejiang Province. Fates of the microalgal cells influenced by activity of the cultured animals largely determined the ef fects of the harmful microalgae. However, it is difficult to detect the in situ process. In this paper, toxic activities of three harmful microalga, namely P rymnesium parvum, Pleurochrysis elongata, Karlodinium veneficum, which were isolated from the local ponds, were comparatively studied based on brine shrimp toxic bioassays. Diff erent lethal activities of live cells, cell debris, cellular extracts, and cell free mediums prepared by different process were analyzed. The results showed that,(1) all of the three microalgal species had density and time dependent lethal ef fects on A rtermia nauplii, while P. parvum was the most toxic one and had acute lethal eff ects in 5 h. No such acute lethal eff ects were observed in P. elongata or K. veneficum;(2) live cells, cell debris and cellular extracts of P. parvum had the same lethal pattern. Prymnesins, toxin from P. parvum, is probably not exotoxic active; For P. elongata, toxic activity mainly came from live cells and cell debris; For K. veneficum, toxic activity was relatively lower compared with the other two species. However, Karlotoxin, toxin from K. veneficum, is exotoxic active. Physical disturbance triggered K. veneficum cells actively releasing toxins, which made it an active predator.展开更多
基金The National High-Tech Project of China under contract No.2007AA09Z110Chinese Ecology and Oceanography of Harmful Algal Blooms Project Ⅱ under contract No.2010CB428702+3 种基金the National Science Foundation Project under contract No.41176141Foundation of State Oceanic Administration of China under contract Nos 2009123 and 20100310the Basic Research Fund of the Second Institute of Oceanography,the State Oceanic Administration of China under contract No.SZ0824Joint Project between Germany and China supported by International Bureau of Federal Ministry for Education and Research under contract No.CHN06/009
文摘Harmful algal blooms often occurred in the East China Sea （ECS） and the German coastal waters of the North Sea but Karlodinium veneficum had not been taxonomically reported. Two strains of Karlodinium （LAMB090611 and LAMB010601） were isolated from the two areas in 2009. The morphological characteristics and molecular phylogeny of two strains are compared on the basis of observation of a light microscope, a scanning electron microscope （SEM）, a laser scanning micro-scope （LSM） and an internal transcribed spacer （ITS） sequence data. The mean cell length of strain LAMB090611 is （14.2 ± 1.8） μm （range 11.1–18.7 μm） and mean width is （10.8 ± 1.5） μm （range 8.2– 14.7 μm）. The mean cell length of strain LAMB010601 is （15.1 ± 1.2） μm （range 12.7–17.9 μm） and the mean width is （11.4 ± 1.1） μm （range 9.1–14.7 μm）, respectively. The two strains are similar in morphological characteristics, including a straight apical groove, distinct ventral pore, sulcal extension, cingulum displacement, two or four irregular shaped chloroplasts within the cell and almost equal sized epicone and hypocone. The large and round nucleus is located at the center or at the hypocone of the cell. The sequence length of the ECS strain LAMB090611 and the German strain LAMB010601 is 640 and 646 bp, respectively. The GC content is 49%. The nucleotide similarity of the two strains is 98.1%. The sequence divergence is 0.003. Both strains are confirmed as Karlo-dinium veneficum （D. Ballantine） J. Larsen and this is the first taxonomic report from China and Germany coastal waters. The population dynamics of this toxic species in the ECS and German coastal waters needs to be investigated in the near future.
基金Supported by the National Key R&D Program of China(No.2017YFC1404301)the National Natural Science Foundation of China(Nos.41906112,41606175)+1 种基金the Science&Technology Basic Resources Investigation Program of China(No.2018FY100200)the Beijing Natural Science Foundation(No.8194059)。
文摘Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were set up from seawater samples taken during the bloom.The cultures were examined for morphological features,ultrastructure characters,photosynthetic pigments,the large subunit(LSU)of the rRNA gene,and the internal transcribed spacer(ITS)sequences,as well as acute toxicity analysis.The cell was unarmored,small-sized,and ovoid,and was characterized by elaborate striations on the epicone and hypocone.The nucleus was large,ellipsoid to oval or kidney-shaped,and centrally located in the cell.A long linear apical groove originated above the sulcus in the ventral epicone and extended to the dorsal side.An elongate,slit-like“ventral pore”was located on the left of the epicone,well away from the apical groove.The chloroplasts were yellowish brown,numerous,band like,and irregularly distributed in the cell periphery.Fucoxanthin was the main accessory pigment composition.Phylogeny topology reconstructed on partial LSU rDNA showed that the unknown dinofl agellate branched as a sister species to Karlodinium sp.(strain IFR981&IFR797,from France)and Karlodinium corrugatum(strain KDGSO08,from Australia),with genetic divergences of 0.6%and 3.3%,respectively.Based on the morphological and molecular phylogenetic analysis,we describe the novel dinofl agellate as Karlodinium elegans sp.nov.A toxicity assay revealed that the clonal culture of K.elegans(strain PTB601)had no adverse eff ect on brine shrimp(Artemia salina)and marine medaka(Oryzias melastigma),indicating it may not be a toxic species.
基金Supported by the National Key R&D Program of China(No.2017YFC1404301)the National Natural Science Foundation of China(No.41606175)the Beijing Natural Science Foundation(No.8194059)。
文摘On May 24-29,2019,a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish(Plectorhinchus cinctus and Pagrosomus major).During the bloom,two major causative organisms were present:Prorocentrum donghaiense(at a concentration of 1.46×10^7 cells/L)and an unknown naked dinoflagellate(4.58×10^6 cells/L).The naked dinoflagellate was isolated and cultured in this study,and its morphological features were examined using light microscopy and scanning electron microscopy.The large subunit(LSU)of the rRNA gene and the internal transcribed spacer(ITS)region of the naked dinoflagellate were also sequenced for field bloom samples and lab culture strains(PT-A and PT-B).On the basis of its morphological characteristics and molecular sequences,the unknown naked dinoflagellate was identified as Karlodinium digitatum.According to the phylogenetic analysis,the Karl.digitatum was most closely related to Karlodinium australe and Karlodinium armiger,and the three species clustered into a single clade of Karlodinium with bootstrap/posterior probability values of 95%/0.99 and 86%/0.99 inferred from LSU and ITS sequences,respectively.Karl.digitatum was first reported as Karenia digitata,a new harmful algal species bloomed in Hong Kong,China,in 1998.In present study,we gave a detailed morphological and phylogenetic description of Karl.digitatum and submitted the molecular sequences of this species to GenBank for the first time.
基金Supported by the Earmarked Fund for Modern Agro-industry Technology Research System,China(No.CARS-49)the Ningbo Science and Technology Research Projects,China(No.2017C110003)+2 种基金the Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Development Fundthe National 111 Project of Chinathe K.C.Wong Magna Fund of Ningbo University
文摘Typical harmful micro-algal species constantly occurred in high density in marine aquaculture ponds in Xiangshan and Sanmen Bay, Zhejiang Province. Fates of the microalgal cells influenced by activity of the cultured animals largely determined the ef fects of the harmful microalgae. However, it is difficult to detect the in situ process. In this paper, toxic activities of three harmful microalga, namely P rymnesium parvum, Pleurochrysis elongata, Karlodinium veneficum, which were isolated from the local ponds, were comparatively studied based on brine shrimp toxic bioassays. Diff erent lethal activities of live cells, cell debris, cellular extracts, and cell free mediums prepared by different process were analyzed. The results showed that,(1) all of the three microalgal species had density and time dependent lethal ef fects on A rtermia nauplii, while P. parvum was the most toxic one and had acute lethal eff ects in 5 h. No such acute lethal eff ects were observed in P. elongata or K. veneficum;(2) live cells, cell debris and cellular extracts of P. parvum had the same lethal pattern. Prymnesins, toxin from P. parvum, is probably not exotoxic active; For P. elongata, toxic activity mainly came from live cells and cell debris; For K. veneficum, toxic activity was relatively lower compared with the other two species. However, Karlotoxin, toxin from K. veneficum, is exotoxic active. Physical disturbance triggered K. veneficum cells actively releasing toxins, which made it an active predator.
