Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated...Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated in the common intertidal macroalga Ulva lactuca L. along the coast of Shantou between aquatic and aerial state. The inorganic carbon dissolved in seawater at present could fully (at 10 ℃ or 20 ℃) or nearly (at 30 ℃) saturate the aquatic photosynthesis of U. lactuca . However, the aerial photosynthesis was limited by current ambient atmospheric CO 2 level, and such a limitation was more severe at higher temperature (20-30 ℃) than at lower temperature (10 ℃). The carbon_saturated maximal photosynthesis of U. lactuca under aerial state was much greater than that under aquatic state at 10 ℃ and 20 ℃, while the maximal photosynthesis under both states was similar at 30 ℃. The aerial values of K m (CO 2) for photosynthesis were higher than the aquatic values. On the contrary, the values of apparent photosynthetic CO 2 conductance under aerial state were considerably lower than that under aquatic state. It was concluded that the increase of atmospheric CO 2 would enhance the primary productivity of U. lactuca through stimulating the photosynthesis under aerial state during low tide.展开更多
The Gross growth efficiency （GGE） is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for th...The Gross growth efficiency （GGE） is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for the ability of a consumer to convert the biomass of food into its population production. In this study, it was firstly applied to estimate the role of amphipods grazing in the biomass dynamics of macroalgae （Ulva lactuca） in Yundang Lagoon （a subtropical eutrophic coastal lagoon, Xiamen City, China）. It was found that amphipods were the dominant group （82.2%-98.7%） in the benthic assemblage, in which five amphipod species （Corophium uenoi, Ampithoe valida, Grandidierella japonica, Grammaropsis laevipalmata andCa-prella panantis） were observed in the lagoon. However, onlyA. valida significantly consumedU. lactuca among these amphipod species. A series of experiments were conducted to estimate the consumption of U. lactuca byA. valida. It was suggested that the monthly secondary production （P） ofA. valida using size frequency method ranged from 2.39 to 13.68 g/m2.GGEofA. valida exponentially reduced with body size and was closely associated with water temperature. Therefore,GGE equation for different months using the temperature recorded during the field investigation was fitted. The monthly consumption ofU. lactuca was figured out to be 86.7-1 549.0 g/m2 by the sum of consumption （P/GGE） byA. valida at different size, ac-counting for 2.0%-37.5% ofU. lactucaproduction. It indicates that the grazing effect ofA. valida did play a role in reducingthe accumulation ofU. lactucabiomass whenA. valida was abundant, but it finally fails to limit the U. lactucagrowth in Yundang Lagoon. Low abundance of A. valida and high nutrient loading may be two major reasons for the outbreak ofU. lactuca bloom in the lagoon.展开更多
Objective:To investigate the antioxidant and cytotoxic properties of the most active extracts from Ulva lactuca and Laurencia obtusa against colon and cervical cancer cell lines.Methods:The antioxidant radical scaveng...Objective:To investigate the antioxidant and cytotoxic properties of the most active extracts from Ulva lactuca and Laurencia obtusa against colon and cervical cancer cell lines.Methods:The antioxidant radical scavenging activity of the algal extracts was estimated using the 2,2-diphenyl-1-picrylhydrazyl colorimetric assay.Moreover,the cytotoxic potential of these bioactive extracts was studied against HCT-116 and HeLa cells by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay.Wound healing analysis was adopted to evaluate the antimetastatic effects of protein extracts from both algae.Cell cycle analysis was performed by flow cytometry,and apoptotic bodies were detected using 4′,6-diamidino-2-phenylindole fluorescent staining.Amino acids of hydrolyzed protein extract were separated and identified chromatographically by high performance liquid chromatography.Results:The green algae Ulva lactuca had higher lipid content than Laurencia obtusa,whereas the latter had higher protein content with high antioxidant capacity.Protein extracts had significant dose-and time-dependent cytotoxicity and anti-metastatic activity against HCT-116 cells.Protein b extracts of both algae obtained from the chloroform:hexane solvent lipid-free residue caused morphological changes and induced apoptosis of HCT-116 cells.Further analysis revealed that apoptosis induced upon Laurencia obtusa protein b treatment was triggered via the ROS pathway,causing a significant increase in the sub-G_(1) population.Glycine and arginine(5.94 and 5.47μM,respectively)were the most common amino acids in Laurencia obtusa protein b extract.Conclusions:Proteins of Laurencia obtusa and Ulva lactuca could be considered as an adjuvant nutraceutical source of pro-apoptotic and anti-metastatic biomolecules against colon cancer.展开更多
The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutr...The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutrients. Kappaphycus contained high amount of ash when compared to U. lactuca. It is revealed that the mercury level in U. lactuca was 0.017 ppm and it was not detected in K. alvarezii. The heavy metal concentration in the selected seaweeds was within the tolerable value reported as quality criteria for edible seaweeds. These seaweeds were also found to be rich sources of vitamin antioxidants namely Vitamin C, total carotenoid, beta carotene, total chlorophyll and polyphenol. The phytochemical screening of the selected seaweeds showed that both seaweeds contained carbohydrates, protein, gums and mulicage, phenols, starch and quinones. Alkaloids was absent in Kappaphycus, saponins was moderate in U. actuca when compared to Kappaphycus. Glycosides, flavonoids, tannins and terpenoids were absent in both the species. The selected seaweeds also possess antibacterial activity. The selected biomass could be recommended for use in dietaries to combat protein energy malnutrition and in particular micronutrient deficiencies.展开更多
Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstu...Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.展开更多
文摘Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated in the common intertidal macroalga Ulva lactuca L. along the coast of Shantou between aquatic and aerial state. The inorganic carbon dissolved in seawater at present could fully (at 10 ℃ or 20 ℃) or nearly (at 30 ℃) saturate the aquatic photosynthesis of U. lactuca . However, the aerial photosynthesis was limited by current ambient atmospheric CO 2 level, and such a limitation was more severe at higher temperature (20-30 ℃) than at lower temperature (10 ℃). The carbon_saturated maximal photosynthesis of U. lactuca under aerial state was much greater than that under aquatic state at 10 ℃ and 20 ℃, while the maximal photosynthesis under both states was similar at 30 ℃. The aerial values of K m (CO 2) for photosynthesis were higher than the aquatic values. On the contrary, the values of apparent photosynthetic CO 2 conductance under aerial state were considerably lower than that under aquatic state. It was concluded that the increase of atmospheric CO 2 would enhance the primary productivity of U. lactuca through stimulating the photosynthesis under aerial state during low tide.
基金The Natural Science Foundation of Fujian Province under contract No.2014J01127the Public Science and Technology Research Funds Projects of Ocean under contract Nos 201205009-3 and 201105012
文摘The Gross growth efficiency （GGE） is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for the ability of a consumer to convert the biomass of food into its population production. In this study, it was firstly applied to estimate the role of amphipods grazing in the biomass dynamics of macroalgae （Ulva lactuca） in Yundang Lagoon （a subtropical eutrophic coastal lagoon, Xiamen City, China）. It was found that amphipods were the dominant group （82.2%-98.7%） in the benthic assemblage, in which five amphipod species （Corophium uenoi, Ampithoe valida, Grandidierella japonica, Grammaropsis laevipalmata andCa-prella panantis） were observed in the lagoon. However, onlyA. valida significantly consumedU. lactuca among these amphipod species. A series of experiments were conducted to estimate the consumption of U. lactuca byA. valida. It was suggested that the monthly secondary production （P） ofA. valida using size frequency method ranged from 2.39 to 13.68 g/m2.GGEofA. valida exponentially reduced with body size and was closely associated with water temperature. Therefore,GGE equation for different months using the temperature recorded during the field investigation was fitted. The monthly consumption ofU. lactuca was figured out to be 86.7-1 549.0 g/m2 by the sum of consumption （P/GGE） byA. valida at different size, ac-counting for 2.0%-37.5% ofU. lactucaproduction. It indicates that the grazing effect ofA. valida did play a role in reducingthe accumulation ofU. lactucabiomass whenA. valida was abundant, but it finally fails to limit the U. lactucagrowth in Yundang Lagoon. Low abundance of A. valida and high nutrient loading may be two major reasons for the outbreak ofU. lactuca bloom in the lagoon.
文摘Objective:To investigate the antioxidant and cytotoxic properties of the most active extracts from Ulva lactuca and Laurencia obtusa against colon and cervical cancer cell lines.Methods:The antioxidant radical scavenging activity of the algal extracts was estimated using the 2,2-diphenyl-1-picrylhydrazyl colorimetric assay.Moreover,the cytotoxic potential of these bioactive extracts was studied against HCT-116 and HeLa cells by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay.Wound healing analysis was adopted to evaluate the antimetastatic effects of protein extracts from both algae.Cell cycle analysis was performed by flow cytometry,and apoptotic bodies were detected using 4′,6-diamidino-2-phenylindole fluorescent staining.Amino acids of hydrolyzed protein extract were separated and identified chromatographically by high performance liquid chromatography.Results:The green algae Ulva lactuca had higher lipid content than Laurencia obtusa,whereas the latter had higher protein content with high antioxidant capacity.Protein extracts had significant dose-and time-dependent cytotoxicity and anti-metastatic activity against HCT-116 cells.Protein b extracts of both algae obtained from the chloroform:hexane solvent lipid-free residue caused morphological changes and induced apoptosis of HCT-116 cells.Further analysis revealed that apoptosis induced upon Laurencia obtusa protein b treatment was triggered via the ROS pathway,causing a significant increase in the sub-G_(1) population.Glycine and arginine(5.94 and 5.47μM,respectively)were the most common amino acids in Laurencia obtusa protein b extract.Conclusions:Proteins of Laurencia obtusa and Ulva lactuca could be considered as an adjuvant nutraceutical source of pro-apoptotic and anti-metastatic biomolecules against colon cancer.
文摘The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutrients. Kappaphycus contained high amount of ash when compared to U. lactuca. It is revealed that the mercury level in U. lactuca was 0.017 ppm and it was not detected in K. alvarezii. The heavy metal concentration in the selected seaweeds was within the tolerable value reported as quality criteria for edible seaweeds. These seaweeds were also found to be rich sources of vitamin antioxidants namely Vitamin C, total carotenoid, beta carotene, total chlorophyll and polyphenol. The phytochemical screening of the selected seaweeds showed that both seaweeds contained carbohydrates, protein, gums and mulicage, phenols, starch and quinones. Alkaloids was absent in Kappaphycus, saponins was moderate in U. actuca when compared to Kappaphycus. Glycosides, flavonoids, tannins and terpenoids were absent in both the species. The selected seaweeds also possess antibacterial activity. The selected biomass could be recommended for use in dietaries to combat protein energy malnutrition and in particular micronutrient deficiencies.
基金Fundaçao para a Ciencia e Tecnologia(FCT,Lisbon,Portugal)through grant PTDC/CAL-ZOO/30238/2017 associated post-doc contract to MMC,CIISA(Project UIDB/00276/2020)a PhD fellowship to DFC(SFRH/BD/126198/2016).
文摘Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.
