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1.
Artigo em Inglês | MEDLINE | ID: mdl-31845243

RESUMO

The phytoplankton (internal driving forces) and environmental variables that affect complex biochemical reactions (external driving forces) play an important role in regulating photosynthetic carbon fixation. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) exists in various phytoplankton species and is an important enzyme in the photosynthetic process. To investigate the phytoplankton composition (internal driving forces), we selected the functional gene of the Rubisco large subunit (rbcL) as the target gene for this study. Phytoplankton gross primary productivity was measured using light and dark biological oxygen demand bottles to assess the carbon sequestration potential. The fundamental environmental indicators were determined to analyze the mechanisms that drive the carbon fixation process. The correlation results indicated that green algae were only controlled by nitrate, and that diatoms were positively correlated with phosphate. The cluster analysis results demonstrated that nitrite was the major driver controlling phytoplankton primary productivity. During the wet seasons (spring and summer), the contribution of the planktonic community respiration to the carbon sequestration potential was higher than net primary productivity (NPP), followed by dissolved organic carbon and nitrate. During the dry season (autumn), NPP, total nitrogen, and nitrite ranked highest in terms of carbon sequestration potential. The contributions of green algae and diatoms to the carbon sequestration potential were temporally higher than those of cyanobacteria. The maximum carbon sequestration potential occurred during autumn because of diatom production and the function of phosphate, whereas the minimum carbon sequestration potential occurred in summer. Spatially, the upstream carbon sequestration potential was higher compared with downstream because of the effect (contribution) of cyanobacteria (Phormidium), diatoms (Surirella solea and Thalassiosira pseudonana), and environmental variable (nitrite). These findings provide a better understanding of the underlying mechanisms of phytoplankton productivity and the influences of environmental variables on carbon sequestration in urban river ecosystems.

2.
Environ Monit Assess ; 191(11): 688, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664528

RESUMO

Understanding the relative impact sizes of environmental factors and nutrients on the high annual variation of phytoplankton abundance in eutrophic rivers is important for aquatic ecosystem management efforts. In this study, we used phytoplankton dynamic datasets in the eutrophic Fenhe River to show the variations and drivers of phytoplankton abundance under complex, fluctuating environmental conditions during 2012-2017. The temporal and spatial variations of nutrients in the river depicted that the total phosphorus (TP) concentration was higher in the wet season and in downstream. There were increases in total nitrogen (TN) concentration in the normal season and in upstream. The structural equation model (SEM) showed that the phytoplankton abundance increased during the wet season despite the decrease in the TN:TP ratio and was reduced upstream due to the highest TN:TP ratio. Among the environmental variables, water temperature (WT) was an important predictor and positively correlated temporally and spatially to phytoplankton. The interaction of nutrients with the phytoplankton community at different temperature levels indicated that different phytoplankton groups have different nutrient requirements. We can conclude that enhances in temperature and TP concentration will significantly increase phytoplankton abundance and dominance of cyanobacteria and green algae in the future, whereas there was insignificant effect on diatoms. These data indicated that temperature and TP content were the important abiotic factors influencing the phytoplankton growth of the water body, which could provide a reference for the evaluation of environmental alterations in the future.


Assuntos
Monitoramento Ambiental , Fitoplâncton/crescimento & desenvolvimento , Temperatura Ambiente , Poluentes da Água/análise , China , Clorófitas , Cianobactérias/crescimento & desenvolvimento , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Eutrofização , Nitrogênio/análise , Nutrientes , Fósforo/análise , Rios/química , Estações do Ano
3.
Bioresour Technol ; 288: 121568, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31154280

RESUMO

In this study, the performance of Chlorococcum sp. GD in synthetic medium with different glucose concentrations (ranging from 1 to10 g/L) was investigated. Moreover, transcriptome sequencing was conducted to clarify the response of the microalga to glucose concentrations. High concentration of glucose (6-10 g/L) not only did not provide a higher yield of biomass but also inhibited photosynthesis. Transcriptomic analysis revealed that the glucose metabolism mainly depended on the glycolysis and the pentose phosphate pathway (PPP) as the microalga was cultivated with 10 g/L glucose. Meanwhile the tricarboxylic acid (TCA) cycle, oxidative phosphorylation and photosynthesis were significantly inhibited. The significant change on carbon metabolic flux caused by the increase in glucose concentration affected the synthesis of reducing power and ATP, which ultimately influenced the growth of the microalga. Appropriate supplement of organic carbon not only enhances the biomass accumulation but also increases the utilization efficiency of organic carbon.


Assuntos
Fotossíntese , Transcriptoma , Biomassa , Carbono , Glucose
4.
Artigo em Inglês | MEDLINE | ID: mdl-30987041

RESUMO

In order to study the effects of nitrogen stress on the lipid synthesis of Parachlorella kessleri TY02 and to understand the changes in growth, photosynthetic pigments, total protein and total carbohydrate contents during lipid accumulation, the cells of the strain were cultured in nitrogen-deficient (N-) and nitrogen-rich (N⁺) media for one week. Changes in cell growth, chlorophyll content, chlorophyll fluorescence parameters, neutral lipid and total lipid content, total protein content and total carbohydrate content were measured and analyzed. The results showed that, under nitrogen stress, the algal strain grew slowly, and chlorophyll and total protein contents decreased, while total carbohydrate and total lipid contents increased. This indicated that, under nitrogen stress, most of the carbon flowed to the synthesis of lipids and carbohydrates. Meanwhile, reducing the nitrogen content was a relatively economical and easy to operate method of promoting lipid accumulation.


Assuntos
Clorófitas/fisiologia , Metabolismo dos Lipídeos , Estresse Fisiológico , Carboidratos/análise , Carbono/metabolismo , Clorofila/metabolismo , Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo , Nitrogênio/metabolismo , Fotossíntese , Proteínas de Plantas/metabolismo
5.
Ecotoxicol Environ Saf ; 171: 274-280, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30612015

RESUMO

There is a concern about the increasing prevalence of health problems related to the ingestion of fluoride (F-) in the developing world. Drinking water is one important source of F-, and the concentration of F- needs to be known to ensure the safety of drinking water. In this study, F- levels in drinking water were investigated across Taiyuan in Shanxi Province, China. Spatial-temporal distribution characteristics and potential associated health risks were analyzed using GIS. We collected 485 samples from shallow wells without any defluoridation treatments between 2008 and 2016. After analyzing the samples of F- content we found that mean F- levels of urban areas (0.61 ±â€¯0.39 mg L-1), suburban areas (0.70 ±â€¯0.87 mg L-1) and for all of Taiyuan city (0.63 ±â€¯0.56 mg L-1) were in optimum range based on the recommendation by USEPA. However, individual locations within industrial areas (e.g. Gujiao District) had higher F- levels (1.06 mg L-1). A concerning result showed that 12.37% of tested locations had F- concentrations larger than 1.0 mg L-1. We calculated F- Health Risk Indices (HRIsF) and found that highest were associated with suburban areas, especially in the year 2009 and 2010. However, from 2008 to 2016, overall F- levels and HRIsF of the sampled groundwater in Taiyuan City showed a decreasing trend. HRIsF in suburban areas was higher than urban areas, possible due to the heavily prevalent coal mining industry in those areas. Specific policies should be formulated to address HRIsF.


Assuntos
Água Potável/química , Fluoretos/análise , Água Subterrânea/química , Poluentes Químicos da Água/análise , China/epidemiologia , Monitoramento Ambiental , Sistemas de Informação Geográfica , Humanos , Medição de Risco , Análise Espaço-Temporal , Saúde Suburbana , Saúde da População Urbana
6.
Environ Monit Assess ; 191(1): 29, 2018 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-30591969

RESUMO

In this paper, the algal cell density of cyanobacteria, green algae, and diatoms and their responses to the hydrochemical factors were analyzed to reveal the structural characteristics of water quality in an urban river. A total of nine sampling sites from upstream to downstream was explored in our study. At each site, the density of algae was identified every week during the wet season (June-October) from 2012 to 2017, and in situ detection was used for the relative 11 hydrochemical variables. The temporal and spatial characteristics of 14 variables were analyzed using a heatmap coupled with the cluster analysis method. The trend of each parameter was analyzed using the smoothing method with locally weighted regression. The nonmetric multidimensional scaling method was employed to detect the temporal and spatial similarities among algae along hydrochemical gradients. The responses of algal density to hydrochemical variables were analyzed using a redundancy analysis. The results showed that the water temperature (Wtemp), pH, dissolved oxygen (DO), cyanobacteria, and diatoms exhibited significant declining trends, and significant increasing trends were shown in the permanganate index, chemical oxygen demand, total nitrogen, ammonia nitrogen, and total phosphorus; the cyanobacteria exhibited certain differences with green algae and diatoms in summer and the downstream areas of the river. The temporal-spatial homogeneity of algal to hydrochemical variables showed the key influencing factors of Wtemp for cyanobacteria density, chlorophyll for green algae density, DO, and pH for diatoms. The results presented here are valuable for deepening our understanding of river ecosystem evaluations and effective environmental management, as well as an important reference for the sustainable development of aquatic biological resources.


Assuntos
Clorófitas/citologia , Cianobactérias/citologia , Diatomáceas/citologia , Monitoramento Ambiental/métodos , Rios/química , Movimentos da Água , China , Clorofila/análise , Clorófitas/crescimento & desenvolvimento , Cianobactérias/crescimento & desenvolvimento , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Eutrofização , Nitrogênio/análise , Fósforo/análise , Estações do Ano , Urbanização , Qualidade da Água
7.
Environ Sci Pollut Res Int ; 25(24): 23917-23928, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29881967

RESUMO

The ability of the agricultural residue of Phragmites australis to serve as an absorbent material used to remove phenol from aqueous solutions in batch and continuous fixed-bed columns was investigated. Prepared adsorbents were characterized by SEM, FTIR, and pHpzc methods. The equilibrium adsorption (qe) of phenol was increased from 9.61 to 29.40 mg/g when the initial phenol concentrations increased from 50 to 150 mg/L. The max adsorption capacity of Phragmites australis was found to be 29.60 mg/g at 30 °C. In column studies, a higher flow rate, higher initial concentration of phenol, and shorter packing layer height increase the column adsorption capacity of phenol. In a batch and continuous fixed-bed column studies, the experiment data was evaluated by some classic models. Fitting degree between the experimental results shows that the pseudo-second-order adsorption kinetics and Langmuir model were the best. Thomas and Yoon-Nelson models were in good agreement with the experimental breakthrough curve data. Both batch and continuous investigation indicated that Phragmites australis could be used as a fine adsorbent to remove phenol and that the adsorption efficiency improved significantly in the column experiment.


Assuntos
Fenol/isolamento & purificação , Poaceae/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Cinética , Modelos Teóricos , Fenol/química , Soluções/química , Poluentes Químicos da Água/química , Purificação da Água/instrumentação
8.
Bioresour Technol ; 264: 311-318, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29857286

RESUMO

Chlorella vulgaris was selected from five freshwater microalgal strains of Chlorophyta, and showed a good potential in nutrients removal from undiluted cattle farm wastewater. By the end of treatment, 62.30%, 81.16% and 85.29% of chemical oxygen demand (COD), ammonium (NH4+-N) and total phosphorus (TP) were removed. Then two two-stage processes were established to enhance nutrients removal efficiency for meeting the discharge standards of China. The process A was the biological treatment via C. vulgaris followed by the biological treatment via C. vulgaris, and the process B was the biological treatment via C. vulgaris followed by the activated carbon adsorption. After 3-5 d of treatment of wastewater via the two processes, the nutrients removal efficiency of COD, NH4+-N and TP were 91.24%-92.17%, 83.16%-94.27% and 90.98%-94.41%, respectively. The integrated two-stage process could strengthen nutrients removal efficiency from undiluted cattle farm wastewater with high organic substance and nitrogen concentration.


Assuntos
Chlorella vulgaris , Eliminação de Resíduos Líquidos , Águas Residuárias , Animais , Bovinos , China , Fazendas , Microalgas , Nitrogênio , Fósforo
9.
PLoS One ; 13(5): e0197729, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29813098

RESUMO

The Rhodophyta Sheathia arcuata is exclusively distributed in freshwater, constituting an important component in freshwater flora. This study presents the first transcriptome profiling of freshwater Rhodophyta taxa. A total of 161,483 assembled transcripts were identified, annotated and classified into different biological categories and pathways based on BLAST against diverse databases. Different gene expression patterns were caused principally by different irradiances considering the similar water conditions of the sampling site when the specimens were collected. Comparison results of gene expression levels under different irradiances revealed that photosynthesis-related pathways significantly up-regulated under the weak light. Molecular responses for improved photosynthetic activity include the transcripts corresponding to antenna proteins (LHCA1 and LHCA4), photosynthetic apparatus proteins (PSBU, PETB, PETC, PETH and beta and gamma subunits of ATPase) and metabolic enzymes in the carbon fixation. Along with photosynthesis, other metabolic activities were also regulated to optimize the growing and development of S. arcuata under appropriate sunlight. Protein-protein interactive networks revealed the most responsive up-expressed transcripts were ribosomal proteins. The de-novo transcriptome assembly of S. arcuata provides a foundation for further investigation on the molecular mechanism of photosynthesis and environmental adaption for freshwater Rhodophyta.


Assuntos
Proteínas de Algas/genética , Perfilação da Expressão Gênica/métodos , Rodófitas/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Luz , Anotação de Sequência Molecular , Fotossíntese , Rodófitas/genética , Análise de Sequência de RNA/métodos
10.
Artigo em Inglês | MEDLINE | ID: mdl-29498694

RESUMO

The performance of a self-flocculating microalga Chlorococcum sp. GD on the flocculation, growth, and lipid accumulation in wastewater with different ammonia nitrogen concentrations was investigated. It was revealed that relative high ammonia nitrogen concentration (20-50 mg·L-1) was beneficial to the flocculation of Chlorococcum sp. GD, and the highest flocculating efficiency was up to 84.4%. It was also found that the highest flocculating efficiency occurred in the middle of the culture (4-5 days) regardless of initial ammonia concentration in wastewater. It was speculated that high flocculating efficiency was likely related to the production of extracellular proteins. 20 mg·L-1 of ammonia was found to be a preferred concentration for both biomass production and lipid accumulation. 92.8% COD, 98.8% ammonia, and 69.4% phosphorus were removed when Chlorococcum sp. GD was cultivated in wastewater with 20 mg·L-1 ammonia. The novelty and significance of the investigation was the integration of flocculation, biomass production, wastewater treatment, and lipid accumulation, simultaneously, which made Chlorococcum sp. GD a potential candidate for wastewater treatment and biodiesel production if harvested in wastewater with suitable ammonia nitrogen concentration.


Assuntos
Amônia/metabolismo , Clorofíceas/fisiologia , Microalgas/fisiologia , Nitrogênio/metabolismo , Águas Residuárias , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Biomassa , Floculação , Águas Residuárias/química , Águas Residuárias/microbiologia
11.
Sci Rep ; 7(1): 2934, 2017 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-28592899

RESUMO

Freshwater representatives of Rhodophyta were sampled and the complete chloroplast and mitochondrial genomes were determined. Characteristics of the chloroplast and mitochondrial genomes were analyzed and phylogenetic relationship of marine and freshwater Rhodophyta were reconstructed based on the organelle genomes. The freshwater member Compsopogon caeruleus was determined for the largest chloroplast genome among multicellular Rhodophyta up to now. Expansion and subsequent reduction of both the genome size and GC content were observed in the Rhodophyta except for the freshwater Compsopogon caeruleus. It was inferred that the freshwater members of Rhodophyta occurred through diverse origins based on evidence of genome size, GC-content, phylogenomic analysis and divergence time estimation. The freshwater species Compsopogon caeruleus and Hildenbrandia rivularis originated and evolved independently at the inland water, whereas the Bangia atropurpurea, Batrachospermum arcuatum and Thorea hispida are derived from the marine relatives. The typical freshwater representatives Thoreales and Batrachospermales are probably derived from the marine relative Palmaria palmata at approximately 415-484 MYA. The origin and evolutionary history of freshwater Rhodophyta needs to be testified with more organelle genome sequences and wider global sampling.


Assuntos
Evolução Biológica , Água Doce , Rodófitas/classificação , Rodófitas/genética , Evolução Molecular , Genes de Plantas , Variação Genética , Genoma de Cloroplastos , Genoma Mitocondrial , Genômica/métodos , Filogenia
12.
BMC Genomics ; 17(1): 612, 2016 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-27516065

RESUMO

BACKGROUND: Porphyridium purpureum has been utilized in important industrial and pharmaceutical fields. The identification of microRNAs (miRNAs) in this unique species is of great importance: such identification can help fill gaps in the small RNA (sRNA) studies of this organism and help to elucidate essential biological processes and their regulation mechanisms in this special micro alga. RESULTS: In this study, 254 high-confidence miRNAs (203 conserved miRNAs and 51 novel miRNAs) were identified by sRNA deep sequencing (sRNA-seq) combined with bioinformatics. A total of 235 putative miRNA families were predicted, including 192 conserved families and 43 species-specific families. The conservation and diversity of predicted miRNA families were analysed in different plant species. Both the 100 % northern blot validation rate (VR) of four randomly selected miRNAs and the results of stem-loop quantitative real time RT-PCR (qRT-PCR) assays of 25 randomly selected miRNAs demonstrated that the majority of the miRNAs identified in this study are credible. A total of 14,958 and 2184 genes were predicted to be targeted by the 186 conserved and 41 novel miRNAs. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that some target genes likely provide valuable references for further understanding of vital functions in P. purpureum. In addition, a cytoscape network will provide some clues for research into the complex biological processes that occur in this unique alga. CONCLUSIONS: We first identified a large set of conserved and novel miRNAs in P. purpureum. The characteristic and validation analysis on miRNAs demonstrated authenticity of identification data. Functional annotation of target genes and metabolic pathways they involved in illuminated the direction for further utilization and development this micro alga based on its unique properties.


Assuntos
Proteínas de Algas/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , MicroRNAs/genética , Porphyridium/genética , RNA de Plantas/genética , Biologia Computacional , Sequência Conservada , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala , Redes e Vias Metabólicas/genética , Anotação de Sequência Molecular
13.
Sci Rep ; 6: 26397, 2016 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-27193824

RESUMO

Chondrus crispus, an economically and medicinally important red alga, is a medicinally active substance and important for anti-tumor research. In this study, 117 C. crispus miRNAs (108 conserved and 9 novel) were identified from 2,416,181 small-RNA reads using high-throughput sequencing and bioinformatics methods. According to the BLAST search against the miRBase database, these miRNAs belonged to 110 miRNA families. Sequence alignment combined with homology searching revealed both the conservation and diversity of predicted potential miRNA families in different plant species. Four and 19 randomly selected miRNAs were validated by northern blotting and stem-loop quantitative real-time reverse transcription polymerase chain reaction detection, respectively. The validation rates (75% and 94.7%) demonstrated that most of the identified miRNAs could be credible. A total of 160 potential target genes were predicted and functionally annotated by Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis. We also analyzed the interrelationship of miRNAs, miRNA-target genes and target genes in C. crispus by constructing a Cytoscape network. The 117 miRNAs identified in our study should supply large quantities of information that will be important for red algae small RNA research.


Assuntos
Chondrus/genética , Biologia Computacional/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , MicroRNAs/genética , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Proteínas de Plantas/genética , RNA de Plantas/genética , Alinhamento de Sequência , Análise de Sequência de RNA/métodos
14.
RNA Biol ; 13(3): 343-52, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26717154

RESUMO

Eucheuma denticulatum, an economically and industrially important red alga, is a valuable marine resource. Although microRNAs (miRNAs) play an essential role in gene post-transcriptional regulation, no research has been conducted to identify and characterize miRNAs in E. denticulatum. In this study, we identified 134 miRNAs (133 conserved miRNAs and one novel miRNA) from 2,997,135 small-RNA reads by high-throughput sequencing combined with bioinformatics analysis. BLAST searching against miRBase uncovered 126 potential miRNA families. A conservation and diversity analysis of predicted miRNA families in different plant species was performed by comparative alignment and homology searching. A total of 4 and 13 randomly selected miRNAs were respectively validated by northern blotting and stem-loop reverse transcription PCR, thereby demonstrating the reliability of the miRNA sequencing data. Altogether, 871 potential target genes were predicted using psRobot and TargetFinder. Target genes classification and enrichment were conducted based on Gene Ontology analysis. The functions of target gene products and associated metabolic pathways were predicted by Kyoto Encyclopedia of Genes and Genomes pathway analysis. A Cytoscape network was constructed to explore the interrelationships of miRNAs, miRNA-target genes and target genes. A large number of miRNAs with diverse target genes will play important roles for further understanding some essential biological processes in E. denticulatum. The uncovered information can serve as an important reference for the protection and utilization of this unique red alga in the future.


Assuntos
Biologia Computacional/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , MicroRNAs/genética , Rodófitas/genética , Análise de Sequência de RNA/métodos , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Redes Reguladoras de Genes , RNA de Plantas/genética , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico
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