Blooms of the toxic dinoflagellate Alexandrium spp.,which produce paralytic shellfish toxins(PSTs),have threatened marine ecosystems for decades.However,their impacts on benthic copepods remain underexplored.Here,we i...Blooms of the toxic dinoflagellate Alexandrium spp.,which produce paralytic shellfish toxins(PSTs),have threatened marine ecosystems for decades.However,their impacts on benthic copepods remain underexplored.Here,we investigated the physiological and biochemical responses of marine benthic copepod Tigriopus japonicus to Alexandrium pacificum.Adult female showed no mortality within 24 h and maintained high survival(>80%)across all A.pacificum concentrations over 96 h,with no significant difference from non-toxic controls.Ingestion rates on A.pacificum and non-toxic controls were similar,when algal prey concentrations were lower than about 2500µgC/L.However,above this threshold,feeding of T.japonicus was significantly depressed by A.pacificum.Six-day exposure induced oxidative stress,marked by elevated level of reactive oxygen species,malondialdehyde,total antioxidant capacity and superoxide dismutase activity,while catalase activity showed a non-significant increase.Moreover,concentration-dependent increase was observed in acetylcholinesterase activity,and its positive correlation with oxidative biomarkers suggests additional roles in coping with stress.Chronic exposure over three generations did not consistently affect development,except for complete development failure in F2 and F3 at the highest concentration.However,moderate-to-high concentrations of A.pacificum significantly impaired reproduction,reducing egg production by 9.66%–96.07%and clutch numbers by 33.33%–55.56%.Our findings indicate that Alexandrium blooms can adversely impact benthic copepod feeding and population recruitment through neurotoxicity and oxidative stress,highlighting the ecological risks of prolonged algal blooms in benthic habitats.展开更多
Suitable temperature and light intensity play important roles in the formation of harmful algae blooms(HABs),which can pose serious threats to aquatic ecosystems and human health.In this study,we measured the growth,p...Suitable temperature and light intensity play important roles in the formation of harmful algae blooms(HABs),which can pose serious threats to aquatic ecosystems and human health.In this study,we measured the growth,physiological function,and paralytic shellfish toxins(PSTs)production of Alexandrium pacificum(CCMA-272),a strain isolated from East China Sea,at different temperatures(15,20,and 25℃)and light intensities(30,60,and 90μmol photons/(m^(2)·s)).Results indicate that temperature and light intensity significantly affected the growth,physiology,and toxigenic potentials of A.pacificum.The optimal conditions for the growth of A.pacificum were observed at 20℃ under60μmol photons/(m^(2)·s).Regarding the production of PSTs,this strain of A.pacificum produced 12 PSTs,including carbamate toxins:saxitoxin(STX),neosaxitoxin(NEO),and gonyautoxin 1–4(GTX1,GTX2,GTX3,GTX4);dicarbamoyl toxins:dicarbamoylsaxitoxin(dcSTX),dicarbamoylgonyautoxin 2,3(dcGTX2,dcGTX3);and N-sulfocarbamoyl toxins:N-sulfocarbamoylgonyautoxin 1,2(C1,C2),and gonyautoxin 5(GTX5).Among all the PSTs,C2 was the most abundant.Low temperature(15℃)and high light intensity(90μmol photons/(m^(2)·s))were beneficial for the production of PSTs in A.pacificum.When cultured at 20 and 25℃,A.pacificum generated comparable total quantities of PSTs,yet the toxicity levels were lower at 25℃.Intra-cellular PSTs contents were greater than extra-cellular PSTs contents,except those under the condition of 25℃ with 30μmol photons/(m^(2)·s).However,as the increase of temperature,A.pacificum released more amounts of analogues with higher toxicity levels(e.g.,STX and dcGTX_(2))into the environment than intracellularly.These findings emphasize the significant sensitivity of A.pacificum to temperature and light intensity,highlighting the importance of evaluating both intra-cellular and extra-cellular PSTs for assessing its toxicity and aiding in the prediction and management of HABs.展开更多
Aim To study isolation and purification of Gonyautoxins from two differentstrains of Alexandrium minutum Halim. Methods Ethanol extracts of the two culture strains ofAlexandrium minutum Halim were fractionated by gel ...Aim To study isolation and purification of Gonyautoxins from two differentstrains of Alexandrium minutum Halim. Methods Ethanol extracts of the two culture strains ofAlexandrium minutum Halim were fractionated by gel filtration and ion exchange chromatography toobtain gonyautoxins. The toxin profiles were tested by HPLC method. Results Both strains containgonyautoxin-1, gonyautoxin-2, gonyautoxin-3 and gonyautoxin-4. The total gonyautoxin content ofAmtk4 strain is almost 10 times higher than that of Amtk2 strain. Conclusion Alexandrium minutumHalim Amtk4 strain is suitable for the preparation of Gonyautoxins.展开更多
采用FIASCO(Fast Isolation by AFLP of Sequences Containing repeats site)方法富集、分离海洋产毒甲藻——塔玛亚历山大藻基因组DNA微卫星位点。结果发现,测序分析的22个克隆中全部含有微卫星位点,插入片段大小为175-687 bp,微卫星DN...采用FIASCO(Fast Isolation by AFLP of Sequences Containing repeats site)方法富集、分离海洋产毒甲藻——塔玛亚历山大藻基因组DNA微卫星位点。结果发现,测序分析的22个克隆中全部含有微卫星位点,插入片段大小为175-687 bp,微卫星DNA的重复数最低4次,最高27次,平均11次;在全部的39个微卫星位点中,其中25个属于完美重复型,13个不完美重复型,1个复合型。为塔玛亚历山大藻系统进化生物学、分子生态学研究提供了很好的标记位点。展开更多
Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects ...Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study. The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandrium tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density(10~2 cell/ml) of Alexandrium tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment,however, with the initial cell density increasing(10~3 and 10~4 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment.展开更多
Paralytic shellfish poisoning (PSP) toxins are potent neurotoxins mainly produced by dinoflagellates and being concentrated in bivalves through food web transfer. Increasing number of findings of toxin-producing bacte...Paralytic shellfish poisoning (PSP) toxins are potent neurotoxins mainly produced by dinoflagellates and being concentrated in bivalves through food web transfer. Increasing number of findings of toxin-producing bacteria in the cells of dinoflagellate such as Alexandriumtamarense supports the hypothesis of the bacterial origin of PSP toxins. Evidence that there are specific symbiosis bacterial taxa associated with the phytoplankton indicates the presence of specific selective mechanisms between them, and implies that the symbiosis bacteria have some vital function to the benefit of the dinoflagellates. Studies on the role of toxin-producing symbiosis bacteria in the marine ecosystem are considered to be becoming more important. Although toxigenic bacteria could be isolated from toxic dinoflagellates, it was not clearly proven whether the isolated bacterial strains based on culture-dependent manner and the corresponding intracellular bacteria were the same because of microbial unculturability. This paper aims to demonstrate the biodiversity of the symbiotic bacteria associated with toxic dinoflagellate A. tamarense using the culture-indepen- dent high-throughput pyrosequencing method, as well as the phylogenetic analysis based on 16S rDNA sequences of the symbiotic cultivable bacteria strains isolated from toxic Alexander tamarense.展开更多
基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.LSKJ202203206)the Fundamental Research Funds for the Central Universities(No.202161069)。
文摘Blooms of the toxic dinoflagellate Alexandrium spp.,which produce paralytic shellfish toxins(PSTs),have threatened marine ecosystems for decades.However,their impacts on benthic copepods remain underexplored.Here,we investigated the physiological and biochemical responses of marine benthic copepod Tigriopus japonicus to Alexandrium pacificum.Adult female showed no mortality within 24 h and maintained high survival(>80%)across all A.pacificum concentrations over 96 h,with no significant difference from non-toxic controls.Ingestion rates on A.pacificum and non-toxic controls were similar,when algal prey concentrations were lower than about 2500µgC/L.However,above this threshold,feeding of T.japonicus was significantly depressed by A.pacificum.Six-day exposure induced oxidative stress,marked by elevated level of reactive oxygen species,malondialdehyde,total antioxidant capacity and superoxide dismutase activity,while catalase activity showed a non-significant increase.Moreover,concentration-dependent increase was observed in acetylcholinesterase activity,and its positive correlation with oxidative biomarkers suggests additional roles in coping with stress.Chronic exposure over three generations did not consistently affect development,except for complete development failure in F2 and F3 at the highest concentration.However,moderate-to-high concentrations of A.pacificum significantly impaired reproduction,reducing egg production by 9.66%–96.07%and clutch numbers by 33.33%–55.56%.Our findings indicate that Alexandrium blooms can adversely impact benthic copepod feeding and population recruitment through neurotoxicity and oxidative stress,highlighting the ecological risks of prolonged algal blooms in benthic habitats.
基金Supported by the National Natural Science Foundation of China(Nos.32101290,52009082)the Natural Science Foundation of Jiangsu Province(No.BK20210364)the Fundamental Research Funds for the Central Universities(No.B220202044)。
文摘Suitable temperature and light intensity play important roles in the formation of harmful algae blooms(HABs),which can pose serious threats to aquatic ecosystems and human health.In this study,we measured the growth,physiological function,and paralytic shellfish toxins(PSTs)production of Alexandrium pacificum(CCMA-272),a strain isolated from East China Sea,at different temperatures(15,20,and 25℃)and light intensities(30,60,and 90μmol photons/(m^(2)·s)).Results indicate that temperature and light intensity significantly affected the growth,physiology,and toxigenic potentials of A.pacificum.The optimal conditions for the growth of A.pacificum were observed at 20℃ under60μmol photons/(m^(2)·s).Regarding the production of PSTs,this strain of A.pacificum produced 12 PSTs,including carbamate toxins:saxitoxin(STX),neosaxitoxin(NEO),and gonyautoxin 1–4(GTX1,GTX2,GTX3,GTX4);dicarbamoyl toxins:dicarbamoylsaxitoxin(dcSTX),dicarbamoylgonyautoxin 2,3(dcGTX2,dcGTX3);and N-sulfocarbamoyl toxins:N-sulfocarbamoylgonyautoxin 1,2(C1,C2),and gonyautoxin 5(GTX5).Among all the PSTs,C2 was the most abundant.Low temperature(15℃)and high light intensity(90μmol photons/(m^(2)·s))were beneficial for the production of PSTs in A.pacificum.When cultured at 20 and 25℃,A.pacificum generated comparable total quantities of PSTs,yet the toxicity levels were lower at 25℃.Intra-cellular PSTs contents were greater than extra-cellular PSTs contents,except those under the condition of 25℃ with 30μmol photons/(m^(2)·s).However,as the increase of temperature,A.pacificum released more amounts of analogues with higher toxicity levels(e.g.,STX and dcGTX_(2))into the environment than intracellularly.These findings emphasize the significant sensitivity of A.pacificum to temperature and light intensity,highlighting the importance of evaluating both intra-cellular and extra-cellular PSTs for assessing its toxicity and aiding in the prediction and management of HABs.
文摘Aim To study isolation and purification of Gonyautoxins from two differentstrains of Alexandrium minutum Halim. Methods Ethanol extracts of the two culture strains ofAlexandrium minutum Halim were fractionated by gel filtration and ion exchange chromatography toobtain gonyautoxins. The toxin profiles were tested by HPLC method. Results Both strains containgonyautoxin-1, gonyautoxin-2, gonyautoxin-3 and gonyautoxin-4. The total gonyautoxin content ofAmtk4 strain is almost 10 times higher than that of Amtk2 strain. Conclusion Alexandrium minutumHalim Amtk4 strain is suitable for the preparation of Gonyautoxins.
文摘采用FIASCO(Fast Isolation by AFLP of Sequences Containing repeats site)方法富集、分离海洋产毒甲藻——塔玛亚历山大藻基因组DNA微卫星位点。结果发现,测序分析的22个克隆中全部含有微卫星位点,插入片段大小为175-687 bp,微卫星DNA的重复数最低4次,最高27次,平均11次;在全部的39个微卫星位点中,其中25个属于完美重复型,13个不完美重复型,1个复合型。为塔玛亚历山大藻系统进化生物学、分子生态学研究提供了很好的标记位点。
文摘Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study. The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandrium tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density(10~2 cell/ml) of Alexandrium tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment,however, with the initial cell density increasing(10~3 and 10~4 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment.
文摘Paralytic shellfish poisoning (PSP) toxins are potent neurotoxins mainly produced by dinoflagellates and being concentrated in bivalves through food web transfer. Increasing number of findings of toxin-producing bacteria in the cells of dinoflagellate such as Alexandriumtamarense supports the hypothesis of the bacterial origin of PSP toxins. Evidence that there are specific symbiosis bacterial taxa associated with the phytoplankton indicates the presence of specific selective mechanisms between them, and implies that the symbiosis bacteria have some vital function to the benefit of the dinoflagellates. Studies on the role of toxin-producing symbiosis bacteria in the marine ecosystem are considered to be becoming more important. Although toxigenic bacteria could be isolated from toxic dinoflagellates, it was not clearly proven whether the isolated bacterial strains based on culture-dependent manner and the corresponding intracellular bacteria were the same because of microbial unculturability. This paper aims to demonstrate the biodiversity of the symbiotic bacteria associated with toxic dinoflagellate A. tamarense using the culture-indepen- dent high-throughput pyrosequencing method, as well as the phylogenetic analysis based on 16S rDNA sequences of the symbiotic cultivable bacteria strains isolated from toxic Alexander tamarense.
