Polar microalgae are microscopic organisms adapted to survive in cold and extreme habitats such as sea-ice,glaciers,lakes and snow.These microorganisms provide an essential basis as primary food sources in polar ecosy...Polar microalgae are microscopic organisms adapted to survive in cold and extreme habitats such as sea-ice,glaciers,lakes and snow.These microorganisms provide an essential basis as primary food sources in polar ecosystems.Despite their ecological importance,polar microalgae remain relatively unexplored compared to their tropical and temperate counterparts,largely due to the practical challenges of obtaining and maintaining material from the harsh polar environments.However,interest has recently surged due to their specific adaptations and potential for utilization in various fields.This review explores the survival strategies of polar microalgae and their commercial applications in healthcare and other fields.We also consider the processes involved in processing polar microalgae,from cultivation to extraction of bioactive compounds.Our findings highlight a growing need for research in this rapidly evolving field to unlock the potential of polar microalgae in multiple fields.展开更多
Microalgae-bacteria system is an emerging alternative for sustainable wastewater treatment.Exploring the structure and diversity of microbial community in microalgae-bacteria system under sulfadiazine stress can contr...Microalgae-bacteria system is an emerging alternative for sustainable wastewater treatment.Exploring the structure and diversity of microbial community in microalgae-bacteria system under sulfadiazine stress can contribute to the understanding of the sulfadiazine behavior in environments.Furthermore,as important carriers of antibiotic resistance genes(ARGs),microalgae can influence the profiles of ARGs either directly or indirectly through the secretion of metabolites.However,the effects of sulfadiazine on ARGs dissemination of microalgae-bacteria systems remain underreported.Herein,the impacts of sulfadiazine(1 mg/L)on the structural diversity and metabolic activity of microorganisms were examined in microalgae-bacteria systems.Results showed thatmicroalgae-bacteria system could remove NH_(4)^(+)-N better(about 72.3%)than activated sludge system,and hydrolysis was the first step in sulfadiazine degradation.A high level of intI1(5.7×10^(4) copies/mL)was detected in the initial media of the microalgae-bacteria system.Microalgae could hamper the rate of horizontal gene transfer activation.Compared with activated sludge system,the abundance of sul genes(sul1,sul2,sul3,and sulA)was significantly lowered after treating with microalgae-bacteria system.Additionally,the number of proteins and the sum of polysaccharides in the extracellular polymeric substances of the activated sludge system were lower than those of themicroalgae-bacteria system.Microalgae can altermicrobial communities.The genus Rozellomycota predominated all samples.Fungi with relatively high abundance increased in the microalgae-bacteria system,including Dipodascaceae,Rhodotorula,and Geotrichum.These results offer valuable insights into the application processes involving microalgae-bacteria system.展开更多
Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.C...Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.Compared with the traditional coal-fired power plant flue gas emission reduction technology,carbon fixation and emission reduction by microalgae is considered as a promising technology due to the advantages of simple process equipment,convenient operation and environmental protection.When the flue gas is treated by microalgae carbon fixation and emission reduction technology,microalgae cells can fix CO_(2) in the flue gas through photosynthesis,and simultaneously absorb NO_(x) and SO_(x) as nitrogen and sulfur sources required for growth.Meanwhile,they can also absorb mercury,selenium,arsenic,cadmium,lead and other heavy metal ions in the flue gas to obtain microalgae biomass.The obtained microalgae biomass can be further transformed into high valueadded products,which has broad development prospects.This paper reviews the mechanisms and pathways of CO_(2) sequestration,the mechanism and impacts of microalgal emission reduction of flue gas pollutants,and the applications of carbon sequestration in industrial flue gas by microalgae.Finally,this paper provides some guidelines and prospects for the research and application of green emission reduction technology for industrial flue gas.展开更多
Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,...Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,high variability in nutrient removal under different trophic types,and difficulty in harvesting biomass limits the large-scale application of microalgae wastewater treatment.This study attempted to employmixotrophic microalgae biofilm to address these issues.The biomass production,microalgal activity,and nutrient removal of Chlorella pyrenoidosa biofilms with different trophic types were compared for nutrient-rich wastewater treatment.The results showed that the biomass productivity of the mixotrophic microalgal biofilm(0.215 g/(L·d))was 2.3,8.6,and 6.0 times higher than that of photoautotrophic microalgal biofilm,heterotrophic microalgal biofilm,and photoautotrophic suspended microalga,respectively.Additionally,the dehydrogenase activity(DHA),indicating microalgal activity,of the mixotrophic biofilm was 2.3 and 16.5 times higher than that of photoautotrophic and heterotrophic biofilms,respectively.Meanwhile,the mixotrophic biofilm removed 96.0%of NH_(4)^(+)-N and 99.2%of PO_(4)^(3-)-P,more efficient than that with other types of biofilms and suspended microalgae.In an open-ended air-lift photobioreactor,the mixotrophic microalgal biofilm produced biomass at 0.12 g/(L·d)and removed 90.0%of NH_(4)^(+)-N and 97.6%of PO_(4)^(3-)-P.This study suggests that the mixotrophic microalgal biofilm shows promise in treating nutrient-rich wastewater and producing microalgal biomass for value-added products.展开更多
Gastrointestinal tract toxicity represents a serious adverse effect of chemotherapy,leading to reduced quality of life and survival.For instance,irinotecan(CPT-11)usually causes severe gastrointestinal toxicity,with a...Gastrointestinal tract toxicity represents a serious adverse effect of chemotherapy,leading to reduced quality of life and survival.For instance,irinotecan(CPT-11)usually causes severe gastrointestinal toxicity,with a lack of effective therapeutic interventions,making treatment often unsustainable.Therefore,development of an effective and safe therapy is crucial for improving chemotherapy efficacy and the patients’quality of life.In this work,we developed a novel approach involving the helical-shaped cyanobacterium microalgae,Spirulina platensis(SP),to carry the bornyl acetate(BA)-loaded chitosan nanoparticles to enhance drug retention in the small intestine.We demonstrated the protection effect of BA against chemotherapy-induced intestinal injury using an epithelial cell model.In a mouse model,orally administered BA-ChNPs@SP accumulated in the small intestine and attenuated inflammation by reducing dsDNA release and oxidative stress.This was concomitant with the restoration of the intestinal barrier and modulation of the immune microenvironment.This work suggests the promise of the microalgae-carrying nanomedicine strategy for treatment of intestinal diseases,emphasizing its potential in addressing chemotherapy-induced gastrointestinal complications.展开更多
Locations around the equator provide unique habitats for microalgae presumably with exceptional vitality.To develop microalga-derived product systems,we previously created a(sub)tropical microalgal collection.In this ...Locations around the equator provide unique habitats for microalgae presumably with exceptional vitality.To develop microalga-derived product systems,we previously created a(sub)tropical microalgal collection.In this study,two Chlorella strains(MEM176 and MEM193),adaptive to typical tropical climate,were isolated from the collection.The production performance was evaluated where both strains showed a robust growth in high temperatures and light intensities.Specifically,the strains MEM176 and MEM193 produced 503.6-mg/(L·d)and 411.3-mg/(L·d)biomass,respectively,with high contents of proteins.Their commercial and nutritional values were emphasized by amino acid compositions(e.g.,proline,valine,and phenylalanine).Particularly,higher amounts of proline were revealed in MEM176(47.9 mg/g dry biomass(DW))and MEM193(47.9 and 59.2 mg/g DW)than available commercial strains.Compared with MEM193,MEM176 produced 129.7%more lipids in which unsaturated fatty acids(particularly linoleic acid andα-linolenic acid)account for 65%of the total lipids.Therefore,it is promising to explore the potential of these Chlorella strains as food additives via outdoor cultivation in tropical area,notably MEM176 that exhibits superiority as sources of essential amino acids and valuable fatty acids.展开更多
Microalgae's adaptability and resilience to Earth's diverse environments have evolved these photosynthetic microor-ganisms into a biotechnological source of industrially relevant physiological functions and bi...Microalgae's adaptability and resilience to Earth's diverse environments have evolved these photosynthetic microor-ganisms into a biotechnological source of industrially relevant physiological functions and biometabolites.Despite this,microalgae-based industries only exploit a handful of species.This lack of biodiversity hinders the expansion of the microalgal industry.Microalgal bioprospecting,searching for novel biological algal resources with new properties,remains a low throughput and time-consuming endeavour due to inefficient workflows that rely on non-selective sampling,monoalgal culture status and outdated,non-standardized characterization techniques.This review will highlight the importance of microalgal bioprospecting and critically explore commonly employed methodologies.We will also explore current advances driving the next generation of smart algal bioprospecting focusing on novel workflows and transdisciplinary methodologies with the potential to enable high-throughput microalgal biodiscoveries.Images adapted from(Addicted04 in Wikipedia File:Australia on the globe(Australia centered).svg.2014.;Jin et al.in ACS Appl Bio Mater 4:5080-5089,2021;Kim et al.in Microchim Acta 189:88,2022;Tony et al.in Lab on a Chip 15,19:3810-3810;Thermo Fisher Scientific INC.in CTS Rotea Brochure).展开更多
Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation...Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy.Ceramide,a central molecule in sphingolipid metabolism,has been widely implicated in the regulation of autophagy.Few researchers have addressed the potential effects of ceramide analogs on suppressing melanin synthesis.However,whether ceramide can induce melanosome autophagy and the potential autophagy-dependent mechanism underlying this phenomenon remain unknown.Here,an active compound from the marine microalgae Emiliania huxleyi extract was firstly isolated and identified as a long-chain C22-ceramide(C22-Cer).In vitro results of mouse B16 melanoma cell experiments showed that treatment with 2-5µmol/L C22-Cer significantly suppressed the increase ofα-MSH-induced melanin levels and tyrosinase activity without cytotoxicity.C22-Cer induced typical hallmarks of autophagy such as accumulation of autophagosomes,enhanced autophagic flux and microtubule-associated protein light chain 3,LC3-II expression,and p62 degradation through activating c-Jun N-terminal kinase(JNK)directly.Furthermore,C22-Cer activated JNK-Bcl-2 signaling,dissociated the Beclin1/Bcl-2 complex,and induced melanosome autophagy without affecting the expression of MITF.Besides,the Ca^(2+)influx induced by treatment with C22-Cer further increased the substantial accumulation of autophagosomes.Together,we found a novel marine-derived compound,C22-Cer,targeting JNK pathway and Ca^(2+)signaling to induce melanosome autophagy and suppress melanin accumulation in B16 cells.This study implicates that C22-Cer might be a potential therapeutic mediator against skin pigmentation in mammals.展开更多
Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This ...Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South India.Water samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and Cd.The samples showed levels of these elements that exceeded World Health Organization recommendations.Pearson correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to others.Water samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium sp.The uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river water.The increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation period.The scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological patterns.This study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.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
The growth and nutrients of photosynthetic organisms are significantly influenced by light spectra,yet this relationship is not well-understood in microalgae.Herein,we studied three microalgae species—Chaetoceros sp....The growth and nutrients of photosynthetic organisms are significantly influenced by light spectra,yet this relationship is not well-understood in microalgae.Herein,we studied three microalgae species—Chaetoceros sp.,Isochrysis galbana,and Tetraselmis helgolandica—distinguished by their pigments.We exposed them to seven light spectra,including white(control),red,orange,green,blue,violet,and full spectrum.The results showed distinct responses in the three microalgae to varying light spectra.Optimal growth occurred under blue,violet,and white lights for Chaetoceros sp.,Ⅰ.galbana,and T.helgolandica,respectively,while orange,red,and green lights inhibited growth.Notably,green light significantly increased the protein content in all three microalgae.Carbohydrate and lipid content exhibited species-specific responses:the highest carbohydrate accumulation was achieved for Chaetoceros sp.under red light(73.27±1.45 mg/g),Ⅰ.galbana under orange light(122.89±12.28 mg/g),and T.helgolandica under blue light(43.62±2.79 mg/g).Meanwhile,the highest lipid content was obtained under violet light for Chaetoceros sp.andⅠ.galbana(250.80±7.27 and 320.23±5.75 mg/g,respectively),and under green light for T.helgolandica(255.12±31.19 mg/g).Furthermore,violet light greatly promoted the accumulation of polyunsaturated fatty acids in all three microalgae.Specific pigment compositions also responded to variations in light spectra.For instance,the diadinoxanthin content in Chaetoceros sp.increased significantly under orange light(194.77±13.78μg/g),while chlorophyll-a content inⅠ.galbana increased significantly under violet and blue lights((88.84±33.46)-(141.38±1.64)μg/g),and in T.helgolandica under red,green,and blue lights((1485.04±190.46)-(1886.60±387.42)μg/g).Additionally,Ⅰ.galbana exhibited the highest fucoxanthin,diadinoxanthin,andβ-carotene contents under white light.In conclusion,our results highlight the species-specific impact of light spectra on microalgae growth and nutrients,providing valuable guidance for flexible application of light spectra in microalgal production to enhance yields and target specific nutrients.展开更多
Modern agricultural practices have posed a detrimental impact on the environment due to their intensive use to meet the food demands of an ever-increasing population.In this context,microalgal bioinoculants,specifical...Modern agricultural practices have posed a detrimental impact on the environment due to their intensive use to meet the food demands of an ever-increasing population.In this context,microalgal bioinoculants,specifically cyanobacteria and green microalgae,have emerged as sustainable options for agricultural practices to improve soil organic carbon,nutrient availability,microbial quality,and plant productivity.An overview of current and future perspectives on the use of microalgal bioinoculants in agriculture practices is presented in this review,along with a discussion of their interactions with soil biotic and abiotic factors that affect soil fertility,plant health,and crop productivity.The benefits of microalgal bioinoculants include releasing agronomically important metabolites(exopolymers and phytohormones)as well as solubilizing soil nutrients.Furthermore,they function as biocontrol agents against soil-borne pathogens and facilitate the establishment of rhizosphere communities of agricultural importance.So far,very few studies have explored the basic mechanisms by which microalgal bioinoculants interact with soil biotic and abiotic factors.In recent years,advanced molecular techniques have contributed to a better understanding of these interactions.展开更多
Depleting global petroleum reserves and skyrocketing prices coupled with succinct supply have been a grave concern,which needs alternative sources to conventional fuels.Oleaginous microalgae have been explored for enh...Depleting global petroleum reserves and skyrocketing prices coupled with succinct supply have been a grave concern,which needs alternative sources to conventional fuels.Oleaginous microalgae have been explored for enhanced lipid production,leading towards biodiesel production.These microalgae have short life cycles,require less labor,and space,and are easy to scale up.Triacylglycerol,the primary source of lipids needed to produce biodiesel,is accumulated by most microalgae.The article focuses on different types of oleaginous microalgae,which can be used as a feedstock to produce biodiesel.Lipid biosynthesis in microalgae occurs through fatty acid synthesis and TAG synthesis approaches.In-depth discussions are held regarding other efficient methods for enhancing fatty acid and TAG synthesis,regulating TAG biosynthesis bypass methods,blocking competing pathways,multigene approach,and genome editing.The most potential targets for gene transformation are hypothesized to be a malic enzyme and diacylglycerol acyltransferase while lowering phosphoenolpyruvate carboxylase activity is reported to be advantageous for lipid synthesis.展开更多
Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results wer...Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results were fitted to the Monod model. U. pertusa had a lower half_saturation constant and maximum growth rate, which were 0.016 μmol/L and 0.16 d -1 respectively, while the growth kinetics of T. subcordiformis were 0.021 μmol/L and 0.83 d -1 . Long_term semicontinuous nutrient competition experiments were performed between T. subcordiformis and U. pertusa under phosphate limitation in laboratory. Loss rates were manipulated to get the same or different resource requirement values ( R * ) of the two species. Comparison between the theoretical predictions derived from Monod kinetics and the outcome of competition experiments indicated that the Monod model could predict the results only when the R * values of the two species were significantly different, and T. subcordiformis displaced U. pertusa when they had the same resource requirements. The Monod model can only partly predict the competition results between microalga and macroalga.展开更多
In order to realize the detection and analysis of microalgae in sediment samples with complex scenes, the project takes advantage of the character of microalgae that they can auto-fluoresce when exposed to the illumin...In order to realize the detection and analysis of microalgae in sediment samples with complex scenes, the project takes advantage of the character of microalgae that they can auto-fluoresce when exposed to the illumination of certain exciation waves. The project takes grey-scale and fluorescent pictures of microalgae in the same field of view and uses the image processing technique to deal with the images, such as threshold segmentation, contour and texture analysis and pattern recognition. The results show that the fluorescent image can effectively elimate the yawp in the complex background and make the consequent image processing more effective and easy. Then the project comes to the conclusion that fluorescence-assisted image processing can realize the detection and analysis of microalgae in sediment samples containing complex scenes.展开更多
Hydrophilic and lipophilic extracts were prepared from 8 microalgal strains, and screened for antimicrobial and antitumor activities. Antimicrobial activity was determined by observing bacterial （ S. aureus, Bacillus...Hydrophilic and lipophilic extracts were prepared from 8 microalgal strains, and screened for antimicrobial and antitumor activities. Antimicrobial activity was determined by observing bacterial （ S. aureus, Bacillus subtilis and Escherichia coh~ and fungal（Aspergillus niger and Penicillium chrysogenum） growth inhibition. All the microalgae had different degrees of antimicrobial activity against one or more microbe - tested, and 56.47% of the extracts showing the anti-S.aureus activity exhibited the antibacterial activity against （MRSA）. Cytotoxic activities were measured in vitro against human cancer cell lines HeLa by the MTT assay. Most of these extracts showed potent activity against the growth of the tumor cells, especially the intracellular lipophilic extracts from Isochrysis galbana Parke 3011 and Isochrysis galbana Parke H29, which exhibited strong antitumor activity against HeLa cell lines. The overall results of this study indicate that the extracts from microalgae represent a potential sources of medicine for the treatment of infectious and cancer diseases.展开更多
[Objective] This study aimed to select microalgae species which are capable to effectively remove arsenic contamination from water under natural conditions. [Method] Four microalgae species [Chlorella sp. （zfsaia）, ...[Objective] This study aimed to select microalgae species which are capable to effectively remove arsenic contamination from water under natural conditions. [Method] Four microalgae species [Chlorella sp. （zfsaia）, Chlorella minata, Chlorella vulgaris and Selenastrum capricormulum] were used as experimental materials and cultured with six different concentrations of As （Ⅲ） （0.5, 1.0, 2.0, 5.0, 10.0, 20.0 mg/L）. Biomass, chlorophyll a content and other physiological indicators were determined to investigate the arsenic tolerance and biosorption of four microalgae species. [Result] Chlorella sp. is sensitive to arsenic toxicity, its growth was inhibited when arsenic concentration exceeded 10 mg/L, with an EC 50 of 17.32 mg/L; when the arsenic concentration was 0-20 mg/L, growth of S.c, ww1 and C.v was not affected, which showed relatively high tolerance to arsenic, with arsenic removal rates of 77.02% , 72.18% and 81.36% respectively after 24 h. [Conclusion] This study indicates that microalgae have good application prospects for processing arsenic wastewater and being indicator plants of arsenic wastewater.展开更多
[Objective] The aim was to select suitable gene for Chlorella identification and to identify the oil-producing microalgae.[Method] Four candidate gene sequences,the nuclear genomic rDNA of the 18S rRNA gene,internal t...[Objective] The aim was to select suitable gene for Chlorella identification and to identify the oil-producing microalgae.[Method] Four candidate gene sequences,the nuclear genomic rDNA of the 18S rRNA gene,internal transcribed spacer（ITS）,internal transcribed spacer Ⅱ（ITS Ⅱ）and the chloroplast rbcL gene,were selected for Chlorella molecular identification.Through these four candidate genes,the genetic variability and distinguish ability between intra-species and inter-species was analyzed to choose the right genes for identification of the high oil-content Chlorella.On this basis,application of these gene segments were classified and identified for five fresh-water isolated Chlorella,which oil-content is more than 30%.[Result] ITS gene was a suitable gene because of its high variation and short fragment length,meanwhile its genetic distance intra-species（0.439 6±0.135 9）was larger than inter-species（0.045 7±0.084 3）.Its sequence length varied between different species whereas highly conserved in the same species.By the application of ITS sequences,respectively,five high oil-content stains were identified as one C.vulgaris,two strains of C.sorokiniana and two strains of algae Chlorella sp.[Conclusion] This study had provided reference for the establishment of identification gene pool of Chlorella.展开更多
Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion a...Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion and glucose absorption,making them key targets for many studies to treat postprandial hyperglycemia.We studied the inhibitory activities of microalgal fucoxanthin against rat-intestinalα-glucosidase and pancreaticα-amylase along with the antidiabetic eff ect to induce diff erentiation in 3T3-L1 pre-adipocytes using Oil Red-O staining.Fucoxanthin displayed strong hindrance activities towardα-amylase in a concentration-dependent manner,with an IC50 value of 0.68mmol/L,whereas weak inhibitory activity against α-glucosidase,with an IC 50 value of 4.75 mmol/L.Fucoxanthin also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/L.During adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/L.However,fucoxanthin had no inhibitory activity on glucose-6-phosphate dehydrogenase.These results suggest that fucoxanthin might be useful for the prevention of obesity or diabetes by inhibiting carbohydrate-hydrolyzing enzymes and lipid accumulation and be utilized as an ingredient for a functional food or dietary supplement.展开更多
Objective:To investigate the antioxidant and anticancer activities of aqueous extracts of nine microalgal species.Methods:Variable percentages of major secondary metabolites(total phenolic content,terpenoids and alkal...Objective:To investigate the antioxidant and anticancer activities of aqueous extracts of nine microalgal species.Methods:Variable percentages of major secondary metabolites(total phenolic content,terpenoids and alkaloids) as well as phycobiliprotein pigments(phycocyanin, allophycocyanin and phycoerythrin) in the aqueous algal extracts were recorded.Antioxidant activity of the algal extracts was performed using 2,2 diphenyl-1-picrylhydrazyl(DPPH) test and 2,2'azino-bis(ethylbenzthiazoline-6-sulfonic acid(ABTS.) radical cation assay.Anticancer efficiency of the algal water extracts was investigated against Ehrlich Ascites Carcinoma cell(EACC) and Human hepatocellular cancer cell line(HepG2).Results:Antioxidant activity of the algal extracts was performed using DPPH test and ABTS.^+ radical cation assays which revealed 30.1-72.4%and 32.0-75.9%respectively.Anticancer efficiency of the algal water extracts was investigated against Ehdich Ascites Carcinoma Cell(EACC) and Human Hepatocellular cancer cell line(HepG2) with an activity ranged 87.25%and 89.4%respectively.Culturing the promising cyanobacteria species;Nostoc muscorum and Oscillatoria sp.under nitrogen stress conditions(increasing and decreasing nitrate content of the normal BG11 medium,1.5 g/L),increased nitrate concentration(3,6 and 9 g/L) led to a remarkable increase in phycobilin pigments followed by an increase in both antioxidant and anticancer activities in both cyanobacterial species.While the decreased nitrate concentration(0.75,0.37 and 0.0 g/L) induced an obvious decrease in phycobilin pigments with complete absence of allophycocyanin in case of Oscillatoria sp.Conclusions:Nitrogen starvation(0.00 g/L nitrate) induced an increase and comparable antioxidant and anticancer activities to those cultured in the highest nitrate content.展开更多
基金supported by the Sultan Mizan Antarctic Research Foundation Smart Partnership(YPASM)Initiative“Photoprotective Potential of Mycosporine-Like Amino Acids(MAAs)and Bioactive Compounds from Antarctic Microalgae on Human Keratinocytes”(Grant number:IMU R 289/2023)。
文摘Polar microalgae are microscopic organisms adapted to survive in cold and extreme habitats such as sea-ice,glaciers,lakes and snow.These microorganisms provide an essential basis as primary food sources in polar ecosystems.Despite their ecological importance,polar microalgae remain relatively unexplored compared to their tropical and temperate counterparts,largely due to the practical challenges of obtaining and maintaining material from the harsh polar environments.However,interest has recently surged due to their specific adaptations and potential for utilization in various fields.This review explores the survival strategies of polar microalgae and their commercial applications in healthcare and other fields.We also consider the processes involved in processing polar microalgae,from cultivation to extraction of bioactive compounds.Our findings highlight a growing need for research in this rapidly evolving field to unlock the potential of polar microalgae in multiple fields.
基金supported by the Key Research Program of Wuhan(No.2022022202015015)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS13)+1 种基金the key projects of National Natural Science Foundation of China(No.2019YFC0408503)Shanghai Tongji Gao Tingyao Environmental Technology Development Foundation.
文摘Microalgae-bacteria system is an emerging alternative for sustainable wastewater treatment.Exploring the structure and diversity of microbial community in microalgae-bacteria system under sulfadiazine stress can contribute to the understanding of the sulfadiazine behavior in environments.Furthermore,as important carriers of antibiotic resistance genes(ARGs),microalgae can influence the profiles of ARGs either directly or indirectly through the secretion of metabolites.However,the effects of sulfadiazine on ARGs dissemination of microalgae-bacteria systems remain underreported.Herein,the impacts of sulfadiazine(1 mg/L)on the structural diversity and metabolic activity of microorganisms were examined in microalgae-bacteria systems.Results showed thatmicroalgae-bacteria system could remove NH_(4)^(+)-N better(about 72.3%)than activated sludge system,and hydrolysis was the first step in sulfadiazine degradation.A high level of intI1(5.7×10^(4) copies/mL)was detected in the initial media of the microalgae-bacteria system.Microalgae could hamper the rate of horizontal gene transfer activation.Compared with activated sludge system,the abundance of sul genes(sul1,sul2,sul3,and sulA)was significantly lowered after treating with microalgae-bacteria system.Additionally,the number of proteins and the sum of polysaccharides in the extracellular polymeric substances of the activated sludge system were lower than those of themicroalgae-bacteria system.Microalgae can altermicrobial communities.The genus Rozellomycota predominated all samples.Fungi with relatively high abundance increased in the microalgae-bacteria system,including Dipodascaceae,Rhodotorula,and Geotrichum.These results offer valuable insights into the application processes involving microalgae-bacteria system.
基金supported by the National Key R&D Program of China(No.2023YFC3709500).
文摘Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.Compared with the traditional coal-fired power plant flue gas emission reduction technology,carbon fixation and emission reduction by microalgae is considered as a promising technology due to the advantages of simple process equipment,convenient operation and environmental protection.When the flue gas is treated by microalgae carbon fixation and emission reduction technology,microalgae cells can fix CO_(2) in the flue gas through photosynthesis,and simultaneously absorb NO_(x) and SO_(x) as nitrogen and sulfur sources required for growth.Meanwhile,they can also absorb mercury,selenium,arsenic,cadmium,lead and other heavy metal ions in the flue gas to obtain microalgae biomass.The obtained microalgae biomass can be further transformed into high valueadded products,which has broad development prospects.This paper reviews the mechanisms and pathways of CO_(2) sequestration,the mechanism and impacts of microalgal emission reduction of flue gas pollutants,and the applications of carbon sequestration in industrial flue gas by microalgae.Finally,this paper provides some guidelines and prospects for the research and application of green emission reduction technology for industrial flue gas.
基金supported by the Natural Science Foundation of Guangdong Province(No.2020A1515011113)the Applied Basic Research Project of Guangzhou(No.202002030455)Zhongshan Science and Technology Plan Project(No.2020AG021).
文摘Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,high variability in nutrient removal under different trophic types,and difficulty in harvesting biomass limits the large-scale application of microalgae wastewater treatment.This study attempted to employmixotrophic microalgae biofilm to address these issues.The biomass production,microalgal activity,and nutrient removal of Chlorella pyrenoidosa biofilms with different trophic types were compared for nutrient-rich wastewater treatment.The results showed that the biomass productivity of the mixotrophic microalgal biofilm(0.215 g/(L·d))was 2.3,8.6,and 6.0 times higher than that of photoautotrophic microalgal biofilm,heterotrophic microalgal biofilm,and photoautotrophic suspended microalga,respectively.Additionally,the dehydrogenase activity(DHA),indicating microalgal activity,of the mixotrophic biofilm was 2.3 and 16.5 times higher than that of photoautotrophic and heterotrophic biofilms,respectively.Meanwhile,the mixotrophic biofilm removed 96.0%of NH_(4)^(+)-N and 99.2%of PO_(4)^(3-)-P,more efficient than that with other types of biofilms and suspended microalgae.In an open-ended air-lift photobioreactor,the mixotrophic microalgal biofilm produced biomass at 0.12 g/(L·d)and removed 90.0%of NH_(4)^(+)-N and 97.6%of PO_(4)^(3-)-P.This study suggests that the mixotrophic microalgal biofilm shows promise in treating nutrient-rich wastewater and producing microalgal biomass for value-added products.
基金the National Key Research and Development Program of China(2022YFE0203600,China)NFSC(81925035,82341232)+2 种基金Program of Shanghai Committee of Science and Technology(21ZR1475200,China)Department of Science and Technology of Guangdong Province(High-Level R&D and Innovative Research Institute 2021B0909050003)SciTech Projects of Zhongshan(CXTD2022011,LJ2021001).
文摘Gastrointestinal tract toxicity represents a serious adverse effect of chemotherapy,leading to reduced quality of life and survival.For instance,irinotecan(CPT-11)usually causes severe gastrointestinal toxicity,with a lack of effective therapeutic interventions,making treatment often unsustainable.Therefore,development of an effective and safe therapy is crucial for improving chemotherapy efficacy and the patients’quality of life.In this work,we developed a novel approach involving the helical-shaped cyanobacterium microalgae,Spirulina platensis(SP),to carry the bornyl acetate(BA)-loaded chitosan nanoparticles to enhance drug retention in the small intestine.We demonstrated the protection effect of BA against chemotherapy-induced intestinal injury using an epithelial cell model.In a mouse model,orally administered BA-ChNPs@SP accumulated in the small intestine and attenuated inflammation by reducing dsDNA release and oxidative stress.This was concomitant with the restoration of the intestinal barrier and modulation of the immune microenvironment.This work suggests the promise of the microalgae-carrying nanomedicine strategy for treatment of intestinal diseases,emphasizing its potential in addressing chemotherapy-induced gastrointestinal complications.
基金Supported by the National Key R&D Program of China(Nos.2021YFA0909600,2021YFE0110100)the National Natural Science Foundation of China(Nos.32060061,32370380)+3 种基金the Key R&D Program of Hainan Province(Nos.ZDYF2024XDNY244,ZDYF2022XDNY140)the Natural Science Foundation of Hainan Province(No.322QN250)the Foreign Expert Foundation of Hainan Province(No.G20230607016E)the Program of Key Lab of Ministry of Education for Utilization and Conservation of Tropical Marine Bioresources(No.2023SCNFKF04)。
文摘Locations around the equator provide unique habitats for microalgae presumably with exceptional vitality.To develop microalga-derived product systems,we previously created a(sub)tropical microalgal collection.In this study,two Chlorella strains(MEM176 and MEM193),adaptive to typical tropical climate,were isolated from the collection.The production performance was evaluated where both strains showed a robust growth in high temperatures and light intensities.Specifically,the strains MEM176 and MEM193 produced 503.6-mg/(L·d)and 411.3-mg/(L·d)biomass,respectively,with high contents of proteins.Their commercial and nutritional values were emphasized by amino acid compositions(e.g.,proline,valine,and phenylalanine).Particularly,higher amounts of proline were revealed in MEM176(47.9 mg/g dry biomass(DW))and MEM193(47.9 and 59.2 mg/g DW)than available commercial strains.Compared with MEM193,MEM176 produced 129.7%more lipids in which unsaturated fatty acids(particularly linoleic acid andα-linolenic acid)account for 65%of the total lipids.Therefore,it is promising to explore the potential of these Chlorella strains as food additives via outdoor cultivation in tropical area,notably MEM176 that exhibits superiority as sources of essential amino acids and valuable fatty acids.
文摘Microalgae's adaptability and resilience to Earth's diverse environments have evolved these photosynthetic microor-ganisms into a biotechnological source of industrially relevant physiological functions and biometabolites.Despite this,microalgae-based industries only exploit a handful of species.This lack of biodiversity hinders the expansion of the microalgal industry.Microalgal bioprospecting,searching for novel biological algal resources with new properties,remains a low throughput and time-consuming endeavour due to inefficient workflows that rely on non-selective sampling,monoalgal culture status and outdated,non-standardized characterization techniques.This review will highlight the importance of microalgal bioprospecting and critically explore commonly employed methodologies.We will also explore current advances driving the next generation of smart algal bioprospecting focusing on novel workflows and transdisciplinary methodologies with the potential to enable high-throughput microalgal biodiscoveries.Images adapted from(Addicted04 in Wikipedia File:Australia on the globe(Australia centered).svg.2014.;Jin et al.in ACS Appl Bio Mater 4:5080-5089,2021;Kim et al.in Microchim Acta 189:88,2022;Tony et al.in Lab on a Chip 15,19:3810-3810;Thermo Fisher Scientific INC.in CTS Rotea Brochure).
基金supported by the National Natural Science Foundation of China(Nos.42076086 and 32202068)Fujian Province Natural Science Foundation of China(Nos.2019J01696 and 2022J01332)the Fujian Province Young and Middle-Aged Teacher Education Research Project(No.JAT200247).
文摘Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored.The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy.Ceramide,a central molecule in sphingolipid metabolism,has been widely implicated in the regulation of autophagy.Few researchers have addressed the potential effects of ceramide analogs on suppressing melanin synthesis.However,whether ceramide can induce melanosome autophagy and the potential autophagy-dependent mechanism underlying this phenomenon remain unknown.Here,an active compound from the marine microalgae Emiliania huxleyi extract was firstly isolated and identified as a long-chain C22-ceramide(C22-Cer).In vitro results of mouse B16 melanoma cell experiments showed that treatment with 2-5µmol/L C22-Cer significantly suppressed the increase ofα-MSH-induced melanin levels and tyrosinase activity without cytotoxicity.C22-Cer induced typical hallmarks of autophagy such as accumulation of autophagosomes,enhanced autophagic flux and microtubule-associated protein light chain 3,LC3-II expression,and p62 degradation through activating c-Jun N-terminal kinase(JNK)directly.Furthermore,C22-Cer activated JNK-Bcl-2 signaling,dissociated the Beclin1/Bcl-2 complex,and induced melanosome autophagy without affecting the expression of MITF.Besides,the Ca^(2+)influx induced by treatment with C22-Cer further increased the substantial accumulation of autophagosomes.Together,we found a novel marine-derived compound,C22-Cer,targeting JNK pathway and Ca^(2+)signaling to induce melanosome autophagy and suppress melanin accumulation in B16 cells.This study implicates that C22-Cer might be a potential therapeutic mediator against skin pigmentation in mammals.
文摘Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South India.Water samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and Cd.The samples showed levels of these elements that exceeded World Health Organization recommendations.Pearson correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to others.Water samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium sp.The uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river water.The increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation period.The scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological patterns.This study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.
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 the National Natural Science Foundation of China(No.32102763)the Ningbo Science and Technology Research Projects+3 种基金China(No.2019B10006)the earmarked fund(No.CARS-49)the Ningbo Science and Technology Research ProjectsChina(No.2024Z276)。
文摘The growth and nutrients of photosynthetic organisms are significantly influenced by light spectra,yet this relationship is not well-understood in microalgae.Herein,we studied three microalgae species—Chaetoceros sp.,Isochrysis galbana,and Tetraselmis helgolandica—distinguished by their pigments.We exposed them to seven light spectra,including white(control),red,orange,green,blue,violet,and full spectrum.The results showed distinct responses in the three microalgae to varying light spectra.Optimal growth occurred under blue,violet,and white lights for Chaetoceros sp.,Ⅰ.galbana,and T.helgolandica,respectively,while orange,red,and green lights inhibited growth.Notably,green light significantly increased the protein content in all three microalgae.Carbohydrate and lipid content exhibited species-specific responses:the highest carbohydrate accumulation was achieved for Chaetoceros sp.under red light(73.27±1.45 mg/g),Ⅰ.galbana under orange light(122.89±12.28 mg/g),and T.helgolandica under blue light(43.62±2.79 mg/g).Meanwhile,the highest lipid content was obtained under violet light for Chaetoceros sp.andⅠ.galbana(250.80±7.27 and 320.23±5.75 mg/g,respectively),and under green light for T.helgolandica(255.12±31.19 mg/g).Furthermore,violet light greatly promoted the accumulation of polyunsaturated fatty acids in all three microalgae.Specific pigment compositions also responded to variations in light spectra.For instance,the diadinoxanthin content in Chaetoceros sp.increased significantly under orange light(194.77±13.78μg/g),while chlorophyll-a content inⅠ.galbana increased significantly under violet and blue lights((88.84±33.46)-(141.38±1.64)μg/g),and in T.helgolandica under red,green,and blue lights((1485.04±190.46)-(1886.60±387.42)μg/g).Additionally,Ⅰ.galbana exhibited the highest fucoxanthin,diadinoxanthin,andβ-carotene contents under white light.In conclusion,our results highlight the species-specific impact of light spectra on microalgae growth and nutrients,providing valuable guidance for flexible application of light spectra in microalgal production to enhance yields and target specific nutrients.
基金the financial support from the Durban University of Technology,the Department of Science and Innovationthe National Research Foundation(Nos.84166 and 129358)of South Africa。
文摘Modern agricultural practices have posed a detrimental impact on the environment due to their intensive use to meet the food demands of an ever-increasing population.In this context,microalgal bioinoculants,specifically cyanobacteria and green microalgae,have emerged as sustainable options for agricultural practices to improve soil organic carbon,nutrient availability,microbial quality,and plant productivity.An overview of current and future perspectives on the use of microalgal bioinoculants in agriculture practices is presented in this review,along with a discussion of their interactions with soil biotic and abiotic factors that affect soil fertility,plant health,and crop productivity.The benefits of microalgal bioinoculants include releasing agronomically important metabolites(exopolymers and phytohormones)as well as solubilizing soil nutrients.Furthermore,they function as biocontrol agents against soil-borne pathogens and facilitate the establishment of rhizosphere communities of agricultural importance.So far,very few studies have explored the basic mechanisms by which microalgal bioinoculants interact with soil biotic and abiotic factors.In recent years,advanced molecular techniques have contributed to a better understanding of these interactions.
基金partially supported by Department of Science and Technology,Science and Engineering Research Board under Teachers Associateship for Research Excellence(TARE)Scheme(File Number TAR/2023/000036).
文摘Depleting global petroleum reserves and skyrocketing prices coupled with succinct supply have been a grave concern,which needs alternative sources to conventional fuels.Oleaginous microalgae have been explored for enhanced lipid production,leading towards biodiesel production.These microalgae have short life cycles,require less labor,and space,and are easy to scale up.Triacylglycerol,the primary source of lipids needed to produce biodiesel,is accumulated by most microalgae.The article focuses on different types of oleaginous microalgae,which can be used as a feedstock to produce biodiesel.Lipid biosynthesis in microalgae occurs through fatty acid synthesis and TAG synthesis approaches.In-depth discussions are held regarding other efficient methods for enhancing fatty acid and TAG synthesis,regulating TAG biosynthesis bypass methods,blocking competing pathways,multigene approach,and genome editing.The most potential targets for gene transformation are hypothesized to be a malic enzyme and diacylglycerol acyltransferase while lowering phosphoenolpyruvate carboxylase activity is reported to be advantageous for lipid synthesis.
文摘Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results were fitted to the Monod model. U. pertusa had a lower half_saturation constant and maximum growth rate, which were 0.016 μmol/L and 0.16 d -1 respectively, while the growth kinetics of T. subcordiformis were 0.021 μmol/L and 0.83 d -1 . Long_term semicontinuous nutrient competition experiments were performed between T. subcordiformis and U. pertusa under phosphate limitation in laboratory. Loss rates were manipulated to get the same or different resource requirement values ( R * ) of the two species. Comparison between the theoretical predictions derived from Monod kinetics and the outcome of competition experiments indicated that the Monod model could predict the results only when the R * values of the two species were significantly different, and T. subcordiformis displaced U. pertusa when they had the same resource requirements. The Monod model can only partly predict the competition results between microalga and macroalga.
文摘In order to realize the detection and analysis of microalgae in sediment samples with complex scenes, the project takes advantage of the character of microalgae that they can auto-fluoresce when exposed to the illumination of certain exciation waves. The project takes grey-scale and fluorescent pictures of microalgae in the same field of view and uses the image processing technique to deal with the images, such as threshold segmentation, contour and texture analysis and pattern recognition. The results show that the fluorescent image can effectively elimate the yawp in the complex background and make the consequent image processing more effective and easy. Then the project comes to the conclusion that fluorescence-assisted image processing can realize the detection and analysis of microalgae in sediment samples containing complex scenes.
基金supported by the Natural Science Foundation of Tianjin (Grant No. 08JCZDJC16600)We also would like to thank Key Development Programs of Tianjin in Science and Technology (Grant No. 06YFGZNC04200)
文摘Hydrophilic and lipophilic extracts were prepared from 8 microalgal strains, and screened for antimicrobial and antitumor activities. Antimicrobial activity was determined by observing bacterial （ S. aureus, Bacillus subtilis and Escherichia coh~ and fungal（Aspergillus niger and Penicillium chrysogenum） growth inhibition. All the microalgae had different degrees of antimicrobial activity against one or more microbe - tested, and 56.47% of the extracts showing the anti-S.aureus activity exhibited the antibacterial activity against （MRSA）. Cytotoxic activities were measured in vitro against human cancer cell lines HeLa by the MTT assay. Most of these extracts showed potent activity against the growth of the tumor cells, especially the intracellular lipophilic extracts from Isochrysis galbana Parke 3011 and Isochrysis galbana Parke H29, which exhibited strong antitumor activity against HeLa cell lines. The overall results of this study indicate that the extracts from microalgae represent a potential sources of medicine for the treatment of infectious and cancer diseases.
基金Supported by Natural Science Foundation of Guangdong Province (10151064101000041)Ph.D. Funds from Ministry of Education of China(20090172120032)~~
文摘[Objective] This study aimed to select microalgae species which are capable to effectively remove arsenic contamination from water under natural conditions. [Method] Four microalgae species [Chlorella sp. （zfsaia）, Chlorella minata, Chlorella vulgaris and Selenastrum capricormulum] were used as experimental materials and cultured with six different concentrations of As （Ⅲ） （0.5, 1.0, 2.0, 5.0, 10.0, 20.0 mg/L）. Biomass, chlorophyll a content and other physiological indicators were determined to investigate the arsenic tolerance and biosorption of four microalgae species. [Result] Chlorella sp. is sensitive to arsenic toxicity, its growth was inhibited when arsenic concentration exceeded 10 mg/L, with an EC 50 of 17.32 mg/L; when the arsenic concentration was 0-20 mg/L, growth of S.c, ww1 and C.v was not affected, which showed relatively high tolerance to arsenic, with arsenic removal rates of 77.02% , 72.18% and 81.36% respectively after 24 h. [Conclusion] This study indicates that microalgae have good application prospects for processing arsenic wastewater and being indicator plants of arsenic wastewater.
基金Supported by Key Project of Knowledge Innovation Project of Chinese Academy of Sciences(KGCX2-YW-374-3)Scientific and Technological Project of Shandong Province(2008GG20007002)~~
文摘[Objective] The aim was to select suitable gene for Chlorella identification and to identify the oil-producing microalgae.[Method] Four candidate gene sequences,the nuclear genomic rDNA of the 18S rRNA gene,internal transcribed spacer（ITS）,internal transcribed spacer Ⅱ（ITS Ⅱ）and the chloroplast rbcL gene,were selected for Chlorella molecular identification.Through these four candidate genes,the genetic variability and distinguish ability between intra-species and inter-species was analyzed to choose the right genes for identification of the high oil-content Chlorella.On this basis,application of these gene segments were classified and identified for five fresh-water isolated Chlorella,which oil-content is more than 30%.[Result] ITS gene was a suitable gene because of its high variation and short fragment length,meanwhile its genetic distance intra-species（0.439 6±0.135 9）was larger than inter-species（0.045 7±0.084 3）.Its sequence length varied between different species whereas highly conserved in the same species.By the application of ITS sequences,respectively,five high oil-content stains were identified as one C.vulgaris,two strains of C.sorokiniana and two strains of algae Chlorella sp.[Conclusion] This study had provided reference for the establishment of identification gene pool of Chlorella.
基金a part of the project titled ’Future Marine Technology Development’ funded by the Ministry of Oceans and Fisheries, Republic of Korea
文摘Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion and glucose absorption,making them key targets for many studies to treat postprandial hyperglycemia.We studied the inhibitory activities of microalgal fucoxanthin against rat-intestinalα-glucosidase and pancreaticα-amylase along with the antidiabetic eff ect to induce diff erentiation in 3T3-L1 pre-adipocytes using Oil Red-O staining.Fucoxanthin displayed strong hindrance activities towardα-amylase in a concentration-dependent manner,with an IC50 value of 0.68mmol/L,whereas weak inhibitory activity against α-glucosidase,with an IC 50 value of 4.75 mmol/L.Fucoxanthin also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/L.During adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/L.However,fucoxanthin had no inhibitory activity on glucose-6-phosphate dehydrogenase.These results suggest that fucoxanthin might be useful for the prevention of obesity or diabetes by inhibiting carbohydrate-hydrolyzing enzymes and lipid accumulation and be utilized as an ingredient for a functional food or dietary supplement.
基金Supported by a grant from STDF.Cairo.Egypt(Project No.312)
文摘Objective:To investigate the antioxidant and anticancer activities of aqueous extracts of nine microalgal species.Methods:Variable percentages of major secondary metabolites(total phenolic content,terpenoids and alkaloids) as well as phycobiliprotein pigments(phycocyanin, allophycocyanin and phycoerythrin) in the aqueous algal extracts were recorded.Antioxidant activity of the algal extracts was performed using 2,2 diphenyl-1-picrylhydrazyl(DPPH) test and 2,2'azino-bis(ethylbenzthiazoline-6-sulfonic acid(ABTS.) radical cation assay.Anticancer efficiency of the algal water extracts was investigated against Ehrlich Ascites Carcinoma cell(EACC) and Human hepatocellular cancer cell line(HepG2).Results:Antioxidant activity of the algal extracts was performed using DPPH test and ABTS.^+ radical cation assays which revealed 30.1-72.4%and 32.0-75.9%respectively.Anticancer efficiency of the algal water extracts was investigated against Ehdich Ascites Carcinoma Cell(EACC) and Human Hepatocellular cancer cell line(HepG2) with an activity ranged 87.25%and 89.4%respectively.Culturing the promising cyanobacteria species;Nostoc muscorum and Oscillatoria sp.under nitrogen stress conditions(increasing and decreasing nitrate content of the normal BG11 medium,1.5 g/L),increased nitrate concentration(3,6 and 9 g/L) led to a remarkable increase in phycobilin pigments followed by an increase in both antioxidant and anticancer activities in both cyanobacterial species.While the decreased nitrate concentration(0.75,0.37 and 0.0 g/L) induced an obvious decrease in phycobilin pigments with complete absence of allophycocyanin in case of Oscillatoria sp.Conclusions:Nitrogen starvation(0.00 g/L nitrate) induced an increase and comparable antioxidant and anticancer activities to those cultured in the highest nitrate content.
