Photosynthetic rates (PR ) of four species of marine single- celled algae were determined by means of 14C-tracer method under the experimental modelling conditions. The effects of environmental factors, such as light,...Photosynthetic rates (PR ) of four species of marine single- celled algae were determined by means of 14C-tracer method under the experimental modelling conditions. The effects of environmental factors, such as light, temperature and nutrients, on the biochemical compositions of the algae were studied. The results indicate that the suitable light intensities for the growth of Phaeodactylum tricorntum, Dunaliella spp, Skeletonema costatum and Isochrysis galbana are in the range from 5. 8 X 103 to 15 x 103 lx, showing an increasing trend of photosynthetic rates with the heightened light intensities. The irradiance response of Dunaliella spp. and Isochrysis galbana is significant. The contents of carbohydrate increase, but those of protein decrease, and the contents of lipids change very little. The optimum temperatures for the growth of the four species of algae are 14, 26, 21 and 26t respectively, characterized by the maxima of PR and the contents of carbohydrate, protein and lipid as well as their variations. The apparent activation energies in the photosynthesis process of Phaeodactylum tricornutum, Dunaliella spp., Skeletonema costatum and Isochrysis galbana are 23. 2, 38. 5, 22. 4 and 61. 7 kJ/mol respectively, and the temperature coefficients for the four algae are 1. 74, 1. 74, 1. 38 and 1. 69 respectively. The peaks of PR appeared in some culture media (N/P = 16 ) of Phaeodactylum tricornutum and Skeletonema costatum, and in other media (N/P = 28) of Dunaliella spp. and Isochurysis galbana. The contents and their variations of carbohydrate, protein and lipid of the four species of algae are all maximum when N/P is equal to 16 in culture media.展开更多
Besides competing with algae for light and mineral nutrients (i. e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of...Besides competing with algae for light and mineral nutrients (i. e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in 'A. tatarinowii water', some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTC) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A. tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 μl/disc, the inhibitory rate was negative; if it was over 45 μl/disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 μl/disc and 45 μl/disc.展开更多
Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i...Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> well known as wakame in South Asia are considered to be large edible brown algae. It provides nutritious source of dietary fiber, vitamin Bs and mineral. The present study aimed to investigate the use of </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> for green synthesis of metallic gold nanoparticles. The synthesized nanoparticles were characterized for physicochemical properties including size measurement and tested </span><i style="font-family:"white-space:normal;">in</i><span style="font-family:"white-space:normal;"> <i>vitro</i></span><span style="font-family:"white-space:normal;"> for their effect on viability of human non-small lung cancer H-460 cell line using the MTT assay. From the results, brown algae were able to chemically form nanoparticles with chloroauric acid solution possibly due to the sulphated polysaccharides found in algae. The particle sizes were found to be approximately 10 nm. The gold nanoparticles stabilized by the algae could decrease the cancer cell viability. However, the properties and biological activity of nanoparticles seemed to depend upon reaction time and temperature. Conclusively, gold nanoparticles synthesized and stabilized by the algae could decrease the cancer cell viability, thus indicating the potential of such nanoparticles for further study for anticancer activity.展开更多
基金the Natural Science Foundation of Fujian Province under contract! No. D92001.
文摘Photosynthetic rates (PR ) of four species of marine single- celled algae were determined by means of 14C-tracer method under the experimental modelling conditions. The effects of environmental factors, such as light, temperature and nutrients, on the biochemical compositions of the algae were studied. The results indicate that the suitable light intensities for the growth of Phaeodactylum tricorntum, Dunaliella spp, Skeletonema costatum and Isochrysis galbana are in the range from 5. 8 X 103 to 15 x 103 lx, showing an increasing trend of photosynthetic rates with the heightened light intensities. The irradiance response of Dunaliella spp. and Isochrysis galbana is significant. The contents of carbohydrate increase, but those of protein decrease, and the contents of lipids change very little. The optimum temperatures for the growth of the four species of algae are 14, 26, 21 and 26t respectively, characterized by the maxima of PR and the contents of carbohydrate, protein and lipid as well as their variations. The apparent activation energies in the photosynthesis process of Phaeodactylum tricornutum, Dunaliella spp., Skeletonema costatum and Isochrysis galbana are 23. 2, 38. 5, 22. 4 and 61. 7 kJ/mol respectively, and the temperature coefficients for the four algae are 1. 74, 1. 74, 1. 38 and 1. 69 respectively. The peaks of PR appeared in some culture media (N/P = 16 ) of Phaeodactylum tricornutum and Skeletonema costatum, and in other media (N/P = 28) of Dunaliella spp. and Isochurysis galbana. The contents and their variations of carbohydrate, protein and lipid of the four species of algae are all maximum when N/P is equal to 16 in culture media.
基金TheNationalNaturalScienceFoundationofChinaandthe"Ninth five"significantBitem (No .KZ 95 1 B1 2 0 1)oftheChineseAcademyofScie
文摘Besides competing with algae for light and mineral nutrients (i. e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in 'A. tatarinowii water', some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTC) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A. tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 μl/disc, the inhibitory rate was negative; if it was over 45 μl/disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 μl/disc and 45 μl/disc.
文摘Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> well known as wakame in South Asia are considered to be large edible brown algae. It provides nutritious source of dietary fiber, vitamin Bs and mineral. The present study aimed to investigate the use of </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> for green synthesis of metallic gold nanoparticles. The synthesized nanoparticles were characterized for physicochemical properties including size measurement and tested </span><i style="font-family:"white-space:normal;">in</i><span style="font-family:"white-space:normal;"> <i>vitro</i></span><span style="font-family:"white-space:normal;"> for their effect on viability of human non-small lung cancer H-460 cell line using the MTT assay. From the results, brown algae were able to chemically form nanoparticles with chloroauric acid solution possibly due to the sulphated polysaccharides found in algae. The particle sizes were found to be approximately 10 nm. The gold nanoparticles stabilized by the algae could decrease the cancer cell viability. However, the properties and biological activity of nanoparticles seemed to depend upon reaction time and temperature. Conclusively, gold nanoparticles synthesized and stabilized by the algae could decrease the cancer cell viability, thus indicating the potential of such nanoparticles for further study for anticancer activity.
文摘循环冷却水中的微藻繁殖会造成微生物污垢滋生,可采用电磁脉冲进行灭藻。为此,首先提出了一种基于Marx发生器和H桥固态调制器的高压脉冲源拓扑,并研制了一台多参数可调高压脉冲发生器,输出的方波脉冲的脉冲频率为1~1 000 s-1,脉冲电压0~6 k V,脉宽1~5μs,最大瞬时输出电流为12 A。同时,针对电场强度、脉宽、频率和处理时间这4个参量设计了正交实验方案,开展脉冲电场对蛋白核小球藻和铜绿微囊藻的灭藻实验。结果表明,脉冲电场处理对微藻生长具有显著抑制作用,且电场强度为抑制实验微藻生长的最重要因素,提高电场强度可以显著增强对微藻生长的抑制效果。此外,正交设计方案有助于以少量实验频次推测获得最佳的电磁脉冲处理参数,实验证实此脉冲源的最佳电参数组合分别为5 k V、5μs、800 Hz、5 min和5 k V、5μs、800 Hz、10 min,对应的藻细胞密度下降率分别为86.2%和94.1%。
