A bloom caused by a diatom, Thalassiosira curviseriata Takano (Bacillariophyta) , is recorded in the East China Sea for the first time in China during a red tide investigation cruise (MC2005 -2) from 27 March to 1...A bloom caused by a diatom, Thalassiosira curviseriata Takano (Bacillariophyta) , is recorded in the East China Sea for the first time in China during a red tide investigation cruise (MC2005 -2) from 27 March to 12 April 2005. This bloom was developed with the competition of Chaetoceros debilis and Skeletonema spp. The highest cell density of T. curviseriata, which has reached 1.27 × 10^6 cells/dm3, was found in the surface and middle water layers of Stas ZD, ZB in the East China Sea (27. 22°-29.48°N, 121.53° - 122. 98°E)in early spring in 2005. During the blooming period of T. curviseriata, the population with high cell density was found in the water area with temperature of 10 -15 ℃ and salinity of 29.0 - 33.5. The percentage of the predominant species, T. curviseriata, has reached 95.8% of total diatom cells at one time in the middle water layer. The morphological characteristics of T. curviseriata, were observed with light microscope (LM) and transmission electronic microscope (TEM). The cells are 5.0 - 12. 6 μm in diameter, connecting each other by mucilaginous thread to form spiral and curved chains. Description and LM and TEM images of T. curviseriata are presented. T. curviseriata is ecologically characterized by eurythermy and euryhalinity, and its population variation is affected mainly by silicate, the ratios of phosphorus to silicon and nitrogen to silicon.展开更多
Gene specific primers and DNA probe were designed based on the sequence of 18S rDNA cloned from the red tide alga Thalassiosira rotula. A real-time fluorescent quantitative PCR (RFQ - PCR) method was developed for q...Gene specific primers and DNA probe were designed based on the sequence of 18S rDNA cloned from the red tide alga Thalassiosira rotula. A real-time fluorescent quantitative PCR (RFQ - PCR) method was developed for quantitative detection of T. rotula. The RFQ - PCR assay data showed that the results obtained with the RFQ - PCR quite good agreement with those with the light microscope (LM) counting method, which suggested that the RFQ - PCR could be a useful method for red tide alga detection.展开更多
Phosphorus(P) is one of the key nutrients for the growth of phytoplankton. In this study, we used a method coupling label-free quantitation with liquid chromatography–mass spectrometry(LFQ–LC–MS/MS) to track th...Phosphorus(P) is one of the key nutrients for the growth of phytoplankton. In this study, we used a method coupling label-free quantitation with liquid chromatography–mass spectrometry(LFQ–LC–MS/MS) to track the change of relative protein abundance between P-replete and P-deficient treatments in a non-model diatom, Thalassiosira weissflogii. Out of the 631 proteins identified, 132 were found to have significant changes in abundance(〉1.5 folds) between the two treatments, especially those proteins involved in macromolecular biosynthesis pathways. For example, the up-regulation of sulfolipid biosynthesis protein in the P-deficient culture suggested a switch from using phospholipids to sulfolipids. In addition, the ribosome subunits and tRNA synthetases were down-regulated, which might explain the decrease in protein content in the P-deficient culture. A vacuolar sorting receptor homologous protein was found to be 9.2-folds up-regulated under P-deficiency, indicating an enhancement in the vacuolar sorting pathway for protein degradation. Our results show that T. weissflogii has sophisticated responses in multiple macromolecular metabolism pathways under P-deficiency, a mechanism which can be critical for this species to survive under various levels of P availability in the environment展开更多
In this study, biosilica of high purity was successfully prepared from marine diatom( Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal tre...In this study, biosilica of high purity was successfully prepared from marine diatom( Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600°C. The SiO_2 contents of N. closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO_2 morphologies of both biosilica are typical amorphous silica. Besides, N. closterium biosilica possessed micropores and fibers with a surface area of 59.81 m^2/g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91 m^2/g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.展开更多
We cultured different-sized fractions of dominant phytoplankton species,Skeletonema costatum,Chaetoceros curvisetus,and Thalassiosira nordenski ldii,collected in different sea areas in various seasons,and measured and...We cultured different-sized fractions of dominant phytoplankton species,Skeletonema costatum,Chaetoceros curvisetus,and Thalassiosira nordenski ldii,collected in different sea areas in various seasons,and measured and compared their C,N,P,Si contents.The N content of these species is similar,while the C,P,and Si contents of S.costatum from eutrophic Changjiang (Yangtze River) estuary are higher than those from Jiaozhou Bay (JZB),particularly the content of Si.The C,N,P,and Si contents of cultured phytoplankton in JZB increase with size fraction augmentation,and the percentages of C,N,and P follow the same trend,while the percentage of Si remain constant.Moreover,S.costatum from small-sized fraction assimilated Si more easily than C.curvisetus and T.nordenski ldii,which is explained by the dominance of S.costatum under the conditions of low SiO 3-Si concentration in JZB.The C,N,P,and Si contents of cultured S.costatum collected during summer and winter are higher,which is consistent with the phytoplankton blooming seasons in JZB.The SiO 3-Si concentration of seawater during spring restrain the growth of phytoplankton,supported by the fact that the N,P,and Si contents and their ratios in cells of cultured S.costatum are low in spring season.展开更多
The presence of diatoms is accompanied by the production of a large amount of extracellular polymeric substances,which are mainly composed of carbohydrates.Transparent exopolymer particles(TEP)are a large class of ext...The presence of diatoms is accompanied by the production of a large amount of extracellular polymeric substances,which are mainly composed of carbohydrates.Transparent exopolymer particles(TEP)are a large class of extracellular polymeric substances with high stickiness that promotes the formation of aggregates and marine snow,which affects marine bio-carbon pump efficiency.The purpose of this research was to determine how temperature increases affect the allocation of cellular carbohydrates and the formation and aggregation of TEP.The results showed that the responses of two different diatom species(Thalassiosira weissflogii and Skeletonema marinoi)differed according to temperature.The cell density and chlorophyll a concentration of the former were not significantly correlated with temperature,while those of the latter were significantly decreased with increasing temperature.This indicates that the two species of diatom may have different heat tolerance ranges.A temperature increase will promote significant formation of TEP by both types of diatoms,including aggregation of S.marinoi as the temperature rises,meaning that the high temperature will produce an aggregate with a larger particle size and thus may increase the sedimentation rate of organic carbon.Moreover,the TEP aggregation of T.weissflogii did not increase;therefore,its particle size was smaller,and so it may remain on the sea surface at high temperatures for longer periods.These influences have a profound impact on the biogeochemical cycling of carbon.展开更多
文章以假微型海链藻(Thalassiosira pseudonana)转录组测序数据为基础,对差异表达的功能基因进行GO(gene ontology)和KEGG(kyoto encyclopedia of genes and genomes)富集分析,以研究低盐胁迫条件对其脂肪酸代谢通路相关功能基因表达的...文章以假微型海链藻(Thalassiosira pseudonana)转录组测序数据为基础,对差异表达的功能基因进行GO(gene ontology)和KEGG(kyoto encyclopedia of genes and genomes)富集分析,以研究低盐胁迫条件对其脂肪酸代谢通路相关功能基因表达的影响。结果发现,不同盐度培养下的假微型海链藻在生长期的第2天与第4天时细胞中与脂肪酸生物合成、脂肪酸延伸的相关基因(如:ACC1、arm)的表达量相对于生长第1天均显著升高,与脂肪酸降解相关基因(如:ACADM、ECI1)的表达量无显著变化;与脂肪酸的生物合成、延长相关基因的表达量在试验组和对照组间存在差异(如:起重要作用的KASⅠ、ACAA2等基因表达量显著增加,但也有少数处于下降或者微变动的状态),与脂肪酸降解过程相关基因的表达量显著上升。展开更多
The effects of light on the fluorescence characteristics and biochemical composition of a marine diatom Tha-lassiosira pseudonana in light and dark cycles were investigated with semi-continuous culture. The results in...The effects of light on the fluorescence characteristics and biochemical composition of a marine diatom Tha-lassiosira pseudonana in light and dark cycles were investigated with semi-continuous culture. The results indicate that, with the increase of growing light intensity, DCMU enhanced fluorescence yield (Fd/Chl), enhanced fluorescence ratio (Fd/F) , cellular carbohydrate content. carbohydrate/chlorophyll a and carbohydrate/protein ratio increased , but the fluorescence yield and cellular chlorophyll a content decreased; The protein content declined with the increase of light intensity in the range of 10- 100 μmol/ (m2·s) and increased at higher than 100 μmol/ (m2·s). Sampling time during the day had great effect on the relationships between growing light intensity and cellular chlorophyll a , carbohydrate content , carbohydrate/chlorophyll a and carbohydrate/protein ratio.展开更多
The effects of nutrients on the fluorescence characteristics and biochemical composition of marine diatom Thalassiosira pseudonana 3H in light and dark cycles were investigated with continuous culture. The results sho...The effects of nutrients on the fluorescence characteristics and biochemical composition of marine diatom Thalassiosira pseudonana 3H in light and dark cycles were investigated with continuous culture. The results show that with the increase of nutrient deficiency, the ratio of enhanced fluorescence to fluorescence (Fd/F), cellular chloropyll-a and protein content of the algae decline, but the fluorescence yield (F/Chl) , DCMU enhanced fluorescence yield (Fd/Chl) , cellular carbohydrate content, carbohydrate/Chl, protein/Chl, carbohydrate/protein increase. The changing amplitude of each parameter is different at different nutrition status, sampling time and different light intensity.展开更多
基金The Major State Basic Research Development Program ("973" Program) of China under contract Nos 2001CB409701 and 2005CB422305the Special Prophase Project of Fujian Science and Technology Major Program of China under contract No. 2005YZ1024the National Natural Science Foundation of China under contract Nos 40627001 and 40476055
文摘A bloom caused by a diatom, Thalassiosira curviseriata Takano (Bacillariophyta) , is recorded in the East China Sea for the first time in China during a red tide investigation cruise (MC2005 -2) from 27 March to 12 April 2005. This bloom was developed with the competition of Chaetoceros debilis and Skeletonema spp. The highest cell density of T. curviseriata, which has reached 1.27 × 10^6 cells/dm3, was found in the surface and middle water layers of Stas ZD, ZB in the East China Sea (27. 22°-29.48°N, 121.53° - 122. 98°E)in early spring in 2005. During the blooming period of T. curviseriata, the population with high cell density was found in the water area with temperature of 10 -15 ℃ and salinity of 29.0 - 33.5. The percentage of the predominant species, T. curviseriata, has reached 95.8% of total diatom cells at one time in the middle water layer. The morphological characteristics of T. curviseriata, were observed with light microscope (LM) and transmission electronic microscope (TEM). The cells are 5.0 - 12. 6 μm in diameter, connecting each other by mucilaginous thread to form spiral and curved chains. Description and LM and TEM images of T. curviseriata are presented. T. curviseriata is ecologically characterized by eurythermy and euryhalinity, and its population variation is affected mainly by silicate, the ratios of phosphorus to silicon and nitrogen to silicon.
基金The research was supported by the National Natural Science Foundation of China under contract No.40406028the National High Technology Research and Development Program of China under contract No.2001AA635090.
文摘Gene specific primers and DNA probe were designed based on the sequence of 18S rDNA cloned from the red tide alga Thalassiosira rotula. A real-time fluorescent quantitative PCR (RFQ - PCR) method was developed for quantitative detection of T. rotula. The RFQ - PCR assay data showed that the results obtained with the RFQ - PCR quite good agreement with those with the light microscope (LM) counting method, which suggested that the RFQ - PCR could be a useful method for red tide alga detection.
基金The National Natural Science Foundation of China(NSFC)under contract No.40925018the National Basic Research Program(973 Program)under contract No.2011CB403603
文摘Phosphorus(P) is one of the key nutrients for the growth of phytoplankton. In this study, we used a method coupling label-free quantitation with liquid chromatography–mass spectrometry(LFQ–LC–MS/MS) to track the change of relative protein abundance between P-replete and P-deficient treatments in a non-model diatom, Thalassiosira weissflogii. Out of the 631 proteins identified, 132 were found to have significant changes in abundance(〉1.5 folds) between the two treatments, especially those proteins involved in macromolecular biosynthesis pathways. For example, the up-regulation of sulfolipid biosynthesis protein in the P-deficient culture suggested a switch from using phospholipids to sulfolipids. In addition, the ribosome subunits and tRNA synthetases were down-regulated, which might explain the decrease in protein content in the P-deficient culture. A vacuolar sorting receptor homologous protein was found to be 9.2-folds up-regulated under P-deficiency, indicating an enhancement in the vacuolar sorting pathway for protein degradation. Our results show that T. weissflogii has sophisticated responses in multiple macromolecular metabolism pathways under P-deficiency, a mechanism which can be critical for this species to survive under various levels of P availability in the environment
基金Supported by the Public Science and Technology Research Funds Projects of Ocean,China(No.201305022)the PhD Start-up Fund of Natural Science Foundation of Guangdong Province,China(No.2014A030310326)
文摘In this study, biosilica of high purity was successfully prepared from marine diatom( Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600°C. The SiO_2 contents of N. closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO_2 morphologies of both biosilica are typical amorphous silica. Besides, N. closterium biosilica possessed micropores and fibers with a surface area of 59.81 m^2/g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91 m^2/g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.
基金Supported by the National Natural Science Foundation of China (No.40776043)National Natural Science Foundation of China for Creative Research Groups (No. 40821004)
文摘We cultured different-sized fractions of dominant phytoplankton species,Skeletonema costatum,Chaetoceros curvisetus,and Thalassiosira nordenski ldii,collected in different sea areas in various seasons,and measured and compared their C,N,P,Si contents.The N content of these species is similar,while the C,P,and Si contents of S.costatum from eutrophic Changjiang (Yangtze River) estuary are higher than those from Jiaozhou Bay (JZB),particularly the content of Si.The C,N,P,and Si contents of cultured phytoplankton in JZB increase with size fraction augmentation,and the percentages of C,N,and P follow the same trend,while the percentage of Si remain constant.Moreover,S.costatum from small-sized fraction assimilated Si more easily than C.curvisetus and T.nordenski ldii,which is explained by the dominance of S.costatum under the conditions of low SiO 3-Si concentration in JZB.The C,N,P,and Si contents of cultured S.costatum collected during summer and winter are higher,which is consistent with the phytoplankton blooming seasons in JZB.The SiO 3-Si concentration of seawater during spring restrain the growth of phytoplankton,supported by the fact that the N,P,and Si contents and their ratios in cells of cultured S.costatum are low in spring season.
基金supported by the National Natural Science Foundation of China(No.31500411)the Guangxi Zhuang Autonomous Region International Platform Project(No.2019AC17008)+4 种基金the Guangxi Beihai Science and Technology Research Focus(Nos.201995048202082021 and 2019D05)the U.S.National Science Foundation(No.OCE 0726369)the Special Fund for Asian Regional Cooperation‘2019 China-ASEAN Marine Science and Technology Cooperation Seminar Project’the China Asia-Pacific Economic Cooperation(APEC)Cooperation Fund Project‘APEC Typical Regional Coral Reef Ecosystem Comprehensive Assessment Technology and Management Cooperation Research’the‘Bilateral and Multilateral International Cooperation’Project of the Central Financial Allocation Program in 2019 and 2020。
文摘The presence of diatoms is accompanied by the production of a large amount of extracellular polymeric substances,which are mainly composed of carbohydrates.Transparent exopolymer particles(TEP)are a large class of extracellular polymeric substances with high stickiness that promotes the formation of aggregates and marine snow,which affects marine bio-carbon pump efficiency.The purpose of this research was to determine how temperature increases affect the allocation of cellular carbohydrates and the formation and aggregation of TEP.The results showed that the responses of two different diatom species(Thalassiosira weissflogii and Skeletonema marinoi)differed according to temperature.The cell density and chlorophyll a concentration of the former were not significantly correlated with temperature,while those of the latter were significantly decreased with increasing temperature.This indicates that the two species of diatom may have different heat tolerance ranges.A temperature increase will promote significant formation of TEP by both types of diatoms,including aggregation of S.marinoi as the temperature rises,meaning that the high temperature will produce an aggregate with a larger particle size and thus may increase the sedimentation rate of organic carbon.Moreover,the TEP aggregation of T.weissflogii did not increase;therefore,its particle size was smaller,and so it may remain on the sea surface at high temperatures for longer periods.These influences have a profound impact on the biogeochemical cycling of carbon.
文摘文章以假微型海链藻(Thalassiosira pseudonana)转录组测序数据为基础,对差异表达的功能基因进行GO(gene ontology)和KEGG(kyoto encyclopedia of genes and genomes)富集分析,以研究低盐胁迫条件对其脂肪酸代谢通路相关功能基因表达的影响。结果发现,不同盐度培养下的假微型海链藻在生长期的第2天与第4天时细胞中与脂肪酸生物合成、脂肪酸延伸的相关基因(如:ACC1、arm)的表达量相对于生长第1天均显著升高,与脂肪酸降解相关基因(如:ACADM、ECI1)的表达量无显著变化;与脂肪酸的生物合成、延长相关基因的表达量在试验组和对照组间存在差异(如:起重要作用的KASⅠ、ACAA2等基因表达量显著增加,但也有少数处于下降或者微变动的状态),与脂肪酸降解过程相关基因的表达量显著上升。
文摘The effects of light on the fluorescence characteristics and biochemical composition of a marine diatom Tha-lassiosira pseudonana in light and dark cycles were investigated with semi-continuous culture. The results indicate that, with the increase of growing light intensity, DCMU enhanced fluorescence yield (Fd/Chl), enhanced fluorescence ratio (Fd/F) , cellular carbohydrate content. carbohydrate/chlorophyll a and carbohydrate/protein ratio increased , but the fluorescence yield and cellular chlorophyll a content decreased; The protein content declined with the increase of light intensity in the range of 10- 100 μmol/ (m2·s) and increased at higher than 100 μmol/ (m2·s). Sampling time during the day had great effect on the relationships between growing light intensity and cellular chlorophyll a , carbohydrate content , carbohydrate/chlorophyll a and carbohydrate/protein ratio.
文摘The effects of nutrients on the fluorescence characteristics and biochemical composition of marine diatom Thalassiosira pseudonana 3H in light and dark cycles were investigated with continuous culture. The results show that with the increase of nutrient deficiency, the ratio of enhanced fluorescence to fluorescence (Fd/F), cellular chloropyll-a and protein content of the algae decline, but the fluorescence yield (F/Chl) , DCMU enhanced fluorescence yield (Fd/Chl) , cellular carbohydrate content, carbohydrate/Chl, protein/Chl, carbohydrate/protein increase. The changing amplitude of each parameter is different at different nutrition status, sampling time and different light intensity.