Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microal...Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and pho- tosynthesis rate; this radiation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a microalgal ecological dynamic model at population and commuity levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae commtmities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microalgae and heterotrophic bacteria and the interaction between them.展开更多
Bioremediation became a promising technology to resolve arsenic(As)contamination in aquatic environment.Since monoculture such as microalgae or bacteria was sensitive to environmental disturbance and vulnerable to con...Bioremediation became a promising technology to resolve arsenic(As)contamination in aquatic environment.Since monoculture such as microalgae or bacteria was sensitive to environmental disturbance and vulnerable to contamination,green microalgae Chlorella vulgaris and arsenite(As(Ⅲ))-oxidizing bacteria Pseudomonas sp.SMS11 were co-cultured to construct algal-bacterial consortia in the current study.The effects of algae-bacteria(A:B)ratio and exposure As(Ⅲ)concentration on algal growth,As speciation and metabolomic profile were investigated.Algal growth arrested when treated with 100 mg/L As(Ⅲ)without the co-cultured bacteria.By contrast,co-cultured with strain SMS11 significantly enhanced As tolerance in C.vulgaris especially with A:B ratio of 1:10.All the As(Ⅲ)in culture media of the consortia were oxidized into As(Ⅴ)on day 7.Methylation of As was observed on day 14.Over 1% and 0.5% of total As were converted into dimethylarsinic acid(DMA)after 21days cultivation when the initial concentrations of As(Ⅲ)were 1 and 10 mg/L,respectively.Metabolomic analysis was further performed to reveal the response of consortia metabolites to external As(Ⅲ).The enriched metabolomic pathways were associated with carbohydrate,amino acid and energy metabolisms.Tricarboxylic acid cycle and glyoxylate and dicarboxylate metabolism were upregulated under As stress due to their biological functions on alleviating oxidative stress and protecting cells.Both carbohydrate and amino acid metabolisms provided precursors and potential substrates for energy production and cell protection under abiotic stress.Alterations of the pathways relevant to carbohydrate or amino acid metabolism were triggered by energy requirement.展开更多
Objective:To study the effect of species of lactic acid bacteria(LAB)from telluric origin on the growth of the microalgae Isochrysis galbana(I.galbana)in small and medium volume flasks.Methods:In the first experiment,...Objective:To study the effect of species of lactic acid bacteria(LAB)from telluric origin on the growth of the microalgae Isochrysis galbana(I.galbana)in small and medium volume flasks.Methods:In the first experiment,7 LAB species[Carnobacterium piscicola,Lactobacillus brevis,Lactobacillus casei ssp.casei,Lactobacillus helveticus,Lactococcus lactis spp.lactis,Leuconostoc mesenteroides spp.mesenteroides(L.mesenteroides spp.mesenteroides)and Pediococcus acidilactici(P.acidilactici)]were inoculated in 250 mL flasks containing microalgae I.galbana(10^(6)cells/mL).After fitting the growth data to two mathematical models,two LAB strains(L.mesenteroides spp.mesenteroides and P.acidilactici)were selected for the second experiment in which those strains were inoculated in medium size(5 L)volume cultures of I.galbana(1.2×10^(5)-1.5×10^(5)cells/mL).The bacterial load in cultures from the first experiment was analyzed by plating on marine agar,MRS agar and thiosulfate citrate bile saltssucrose media.Results:All strains of LAB tested enhanced the growth rate and the final biomass yield of I.galbana cultures,even in the absence of nutrients in the media.The best overall results and the maximal final cell densities in small flasks were achieved with strains L.mesenteroides spp.mesenteroides and P.acidilactici,respectively.These two strains also stimulated the growth(40%and 16%with respect to controls)of I.galbana in medium size volumes.For most strains,CFU values of LAB remained stable(10^(5)-10^(8)CFU/mL)for at least 4 days.A high variability was observed in bacteria strains among treatments,with Pseudomonas and Moraxella being the most abundant bacteria.Conclusions:The results of present study showed that the growth of I.galbana in both small and medium size volumes was enhanced by LAB,both in the absence and the presence of nutrients in the culture.The highest final biomass was achieved by adding P.acidilactici,whereas Carnobacterium piscicola and L.mesenteroides spp.mesenteroides provided maximal growth rates.The former also showed an inhibitory effect on Moraxella.展开更多
基金supported by The National Natural Science Foundation of China (No. 30270258)Program for New Century Excellent Talents in University (NCET-05-0597).
文摘Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and pho- tosynthesis rate; this radiation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a microalgal ecological dynamic model at population and commuity levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae commtmities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microalgae and heterotrophic bacteria and the interaction between them.
基金supported by the National Natural Science Foundation of China(No.41977351)the Natural Science Foundation of Hunan Province,China(No.2020JJ4698)。
文摘Bioremediation became a promising technology to resolve arsenic(As)contamination in aquatic environment.Since monoculture such as microalgae or bacteria was sensitive to environmental disturbance and vulnerable to contamination,green microalgae Chlorella vulgaris and arsenite(As(Ⅲ))-oxidizing bacteria Pseudomonas sp.SMS11 were co-cultured to construct algal-bacterial consortia in the current study.The effects of algae-bacteria(A:B)ratio and exposure As(Ⅲ)concentration on algal growth,As speciation and metabolomic profile were investigated.Algal growth arrested when treated with 100 mg/L As(Ⅲ)without the co-cultured bacteria.By contrast,co-cultured with strain SMS11 significantly enhanced As tolerance in C.vulgaris especially with A:B ratio of 1:10.All the As(Ⅲ)in culture media of the consortia were oxidized into As(Ⅴ)on day 7.Methylation of As was observed on day 14.Over 1% and 0.5% of total As were converted into dimethylarsinic acid(DMA)after 21days cultivation when the initial concentrations of As(Ⅲ)were 1 and 10 mg/L,respectively.Metabolomic analysis was further performed to reveal the response of consortia metabolites to external As(Ⅲ).The enriched metabolomic pathways were associated with carbohydrate,amino acid and energy metabolisms.Tricarboxylic acid cycle and glyoxylate and dicarboxylate metabolism were upregulated under As stress due to their biological functions on alleviating oxidative stress and protecting cells.Both carbohydrate and amino acid metabolisms provided precursors and potential substrates for energy production and cell protection under abiotic stress.Alterations of the pathways relevant to carbohydrate or amino acid metabolism were triggered by energy requirement.
基金Supported by European Commission(Project PROBE,Q5RS-2000-31457)CICYT(Spain,FEDER,1FD97-0044-C03-01,02 and 03)Dr.J.A.Vázquez Álvarez had a postdoctoral contract(CSIC-I3P-PC 2003,European Social Fund).
文摘Objective:To study the effect of species of lactic acid bacteria(LAB)from telluric origin on the growth of the microalgae Isochrysis galbana(I.galbana)in small and medium volume flasks.Methods:In the first experiment,7 LAB species[Carnobacterium piscicola,Lactobacillus brevis,Lactobacillus casei ssp.casei,Lactobacillus helveticus,Lactococcus lactis spp.lactis,Leuconostoc mesenteroides spp.mesenteroides(L.mesenteroides spp.mesenteroides)and Pediococcus acidilactici(P.acidilactici)]were inoculated in 250 mL flasks containing microalgae I.galbana(10^(6)cells/mL).After fitting the growth data to two mathematical models,two LAB strains(L.mesenteroides spp.mesenteroides and P.acidilactici)were selected for the second experiment in which those strains were inoculated in medium size(5 L)volume cultures of I.galbana(1.2×10^(5)-1.5×10^(5)cells/mL).The bacterial load in cultures from the first experiment was analyzed by plating on marine agar,MRS agar and thiosulfate citrate bile saltssucrose media.Results:All strains of LAB tested enhanced the growth rate and the final biomass yield of I.galbana cultures,even in the absence of nutrients in the media.The best overall results and the maximal final cell densities in small flasks were achieved with strains L.mesenteroides spp.mesenteroides and P.acidilactici,respectively.These two strains also stimulated the growth(40%and 16%with respect to controls)of I.galbana in medium size volumes.For most strains,CFU values of LAB remained stable(10^(5)-10^(8)CFU/mL)for at least 4 days.A high variability was observed in bacteria strains among treatments,with Pseudomonas and Moraxella being the most abundant bacteria.Conclusions:The results of present study showed that the growth of I.galbana in both small and medium size volumes was enhanced by LAB,both in the absence and the presence of nutrients in the culture.The highest final biomass was achieved by adding P.acidilactici,whereas Carnobacterium piscicola and L.mesenteroides spp.mesenteroides provided maximal growth rates.The former also showed an inhibitory effect on Moraxella.
