The effects of temperature and different forms of nutrients on Chattonella marina growth have been investigated in strains isolated from the Daya Bay, the South China Sea. The strain of C. marina preferred high temper...The effects of temperature and different forms of nutrients on Chattonella marina growth have been investigated in strains isolated from the Daya Bay, the South China Sea. The strain of C. marina preferred high temperatures, with an optimal temperature of 25℃, and 18℃ was the minimum for its survival. Higher cell number and growth rate were obtained in high nitrogen and phosphorus concentrations （500 μg/L, 74μg/L） than under nutrient limitation. Nitrogen influenced the growth most, as the specific growth rate and maximum cell density were lower in nitrogen- limited cultures than noted under phosphorus limitation or under limitation from both. C. marina was capable of using many kinds of organic nitrogen sources including L-serine （L-Ser）, glycine （Gly）, alanine （Ala）, L-threonine （L-Thr）, glutamic acid （Glu） and urea, but could not utilize uric acid. Various forms of organic phosphorus compound such as glucose-6-phosphate （G6P）, sodium glycerophosphate （GYP）, adenosine triphosphate （ATP）, adenosine monophosphate （AMP）, cyti- dine monophosphate （CMP）, guanosine monophosphate （GMP）, uridine monophosphate （UMP）, 4-nitrophenylphosphate （NPP） and triethyl phosphate （TEP） supported the growth as well. Algal cells had the ability to sustain growth under nitrogenand/or phosphorus-free conditions particularly under phosphorus depleted condition. These results led to the hypothesis that high loading of nitrogen has played an important role in frequent C. marina blooms in the past decade, and its capability for utilization of diverse forms of organic nutrients and growth in low nutrient conditions make this species a likely recurrent dominant in the Daya Bay phytoplankton assemblages, visible as more frequent blooms.展开更多
Cultivable bacteria coexisting in the cultures of two microalgal species, Chattonella marina(Raphidophyceae)and Skeletonema costatum(diatom, Bacillariophyceae), which have been maintained in the laboratory for several...Cultivable bacteria coexisting in the cultures of two microalgal species, Chattonella marina(Raphidophyceae)and Skeletonema costatum(diatom, Bacillariophyceae), which have been maintained in the laboratory for several years, were examined in this study. Forty-eight and thirty-four cultivable bacterial strains were isolated from different growth stages of C. marina and S. costatum cultures, respectively. A total of twelve unique bacterial phylotypes were isolated. These bacterial phylotypes belonged to Alphaproteobacteria, Gammaproteobacteria,Bacteroidetes, and Actinobacteria. Alphaproteobacteria predominated in phycospheres of both microalgae, and Rhodobacteraceae was the most common family. Bacterial phylotypes were more diversified in cultures of S.costatum than in those of C. marina. Bacterial concentrations increased remarkably after the late stationary phase of C. marina, which might account for the decline in algal cells. One phylotype of S. costatum-associated bacteria had inhibitory effects on Chaetoceros curvisetus(Bacillariophyceae). However, most bacterial phylotypes from cultures of C. marina showed significant inhibition of the growth of C. curvisetus. The results suggested that bacteria associated with C. marina might have some ecological roles in its competition with diatoms.展开更多
基金The National Natural Science Foundation of China under contract No.41076093the Fundamental Research Funds for the Central Universities
文摘The effects of temperature and different forms of nutrients on Chattonella marina growth have been investigated in strains isolated from the Daya Bay, the South China Sea. The strain of C. marina preferred high temperatures, with an optimal temperature of 25℃, and 18℃ was the minimum for its survival. Higher cell number and growth rate were obtained in high nitrogen and phosphorus concentrations （500 μg/L, 74μg/L） than under nutrient limitation. Nitrogen influenced the growth most, as the specific growth rate and maximum cell density were lower in nitrogen- limited cultures than noted under phosphorus limitation or under limitation from both. C. marina was capable of using many kinds of organic nitrogen sources including L-serine （L-Ser）, glycine （Gly）, alanine （Ala）, L-threonine （L-Thr）, glutamic acid （Glu） and urea, but could not utilize uric acid. Various forms of organic phosphorus compound such as glucose-6-phosphate （G6P）, sodium glycerophosphate （GYP）, adenosine triphosphate （ATP）, adenosine monophosphate （AMP）, cyti- dine monophosphate （CMP）, guanosine monophosphate （GMP）, uridine monophosphate （UMP）, 4-nitrophenylphosphate （NPP） and triethyl phosphate （TEP） supported the growth as well. Algal cells had the ability to sustain growth under nitrogenand/or phosphorus-free conditions particularly under phosphorus depleted condition. These results led to the hypothesis that high loading of nitrogen has played an important role in frequent C. marina blooms in the past decade, and its capability for utilization of diverse forms of organic nutrients and growth in low nutrient conditions make this species a likely recurrent dominant in the Daya Bay phytoplankton assemblages, visible as more frequent blooms.
基金The National Natural Science Foundation of China under contract Nos 41476132 and 41276154
文摘Cultivable bacteria coexisting in the cultures of two microalgal species, Chattonella marina(Raphidophyceae)and Skeletonema costatum(diatom, Bacillariophyceae), which have been maintained in the laboratory for several years, were examined in this study. Forty-eight and thirty-four cultivable bacterial strains were isolated from different growth stages of C. marina and S. costatum cultures, respectively. A total of twelve unique bacterial phylotypes were isolated. These bacterial phylotypes belonged to Alphaproteobacteria, Gammaproteobacteria,Bacteroidetes, and Actinobacteria. Alphaproteobacteria predominated in phycospheres of both microalgae, and Rhodobacteraceae was the most common family. Bacterial phylotypes were more diversified in cultures of S.costatum than in those of C. marina. Bacterial concentrations increased remarkably after the late stationary phase of C. marina, which might account for the decline in algal cells. One phylotype of S. costatum-associated bacteria had inhibitory effects on Chaetoceros curvisetus(Bacillariophyceae). However, most bacterial phylotypes from cultures of C. marina showed significant inhibition of the growth of C. curvisetus. The results suggested that bacteria associated with C. marina might have some ecological roles in its competition with diatoms.
文摘研究了海洋卡盾藻在不同生长阶段和不同密度下对卤虫的急性毒性效应.结果表明,海洋卡盾藻的含藻培养液和除藻过滤液均对卤虫有致死作用,且前者毒性大于后者.对数生长初期的海洋卡盾藻含藻培养液的毒性作用最强,卤虫暴露在3.0×104cells/mL藻液48h后,死亡率达到83%;对数生长后期海洋卡盾藻含藻培养液也具有较强的毒性,48 h卤虫死亡率为73%;衰亡期含藻培养液毒性最弱,48 h卤虫死亡率为33%.海洋卡盾藻含藻培养液和除藻过滤液(对数生长期,10 d)的浓度对数与卤虫的死亡机率单位呈线性关系,含藻培养液对卤虫24 h半致死浓度(LD50)为1.92×104cells/mL,而除藻过滤液对卤虫的24 h LD50为3.34×104cells/mL.卤虫在海洋卡盾藻含藻培养液中的暴露时间(48 h内)与死亡率呈线性相关关系,在藻密度为3.75×104cells/mL时,海洋卡盾藻含藻培养液对卤虫的半致死时间(LT50)为17.3 h.
