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1.
Sci Total Environ ; 932: 172856, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38697534

RESUMEN

Antibiotics are frequently detected in surface water and pose potential threats to organisms in aquatic ecosystem such as microalgae. The occurrence of biphasic dose responses raised the possibility of stimulation of microalgal biomass by antibiotics at environmental-relevant concentration and caused potential ecological risk such as algal bloom. However, the underlying mechanisms of low concentration-induced hormetic effects are not well understood. In this study, we evaluated the hormesis of ofloxacin on Chlorella pyrenoidosa under environmental-relevant concentration and long-term exposure. Results showed the hormetic effects of ofloxacin on cell density and carbon fixation rate (RC). The predicted maximum promotion was 17.45 % by 16.84 µg/L and 20.08 % by 15.78 µg/L at 21 d, respectively. The predicted maximum concentration of non-effect on cell density and RC at 21 d was 3.24 mg/L and 1.44 mg/L, respectively. Ofloxacin induced the mobilization of pigments and antioxidant enzymes to deal with oxidative stress. PCA analysis revealed Chl-a/Chl-b could act as a more sensitive biomarker under acute exposure while chlorophyll fluorescence parameters were in favor of monitoring long-term implication. The hormesis in increased secretion of extracellular organic matters was regarded as a defensive mechanism and accelerated indirect photodegradation of ofloxacin. Bioremoval was dominant and related to biomass accumulation in the total dissipation while abiotic removal appeared slight contributions. This study provided new insights into the understanding of hormesis of microalgae induced by antibiotics.


Asunto(s)
Antibacterianos , Chlorella , Hormesis , Ofloxacino , Contaminantes Químicos del Agua , Chlorella/efectos de los fármacos , Ofloxacino/toxicidad , Contaminantes Químicos del Agua/toxicidad , Antibacterianos/toxicidad , Microalgas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos
2.
Aquat Toxicol ; 271: 106937, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38728928

RESUMEN

In aquaculture around the world, sulfamonomethoxine (SMM), a long-acting antibiotic that harms microalgae, is widely employed in combination with trimethoprim (TMP), a synergist. However, their combined toxicity to microalgae under long-term exposures at environmentally relevant concentrations remains poorly understood. Therefore, we studied the effects of SMM single-exposures and co-exposures (SMM:TMP=5:1) at concentrations of 5 µg/L and 500 µg/L on Chlorella pyrenoidosa within one aquacultural drainage cycle (15 days). Photosynthetic activity and N assimilating enzyme activities were employed to evaluate microalgal nutrient assimilation. Oxidative stress and flow cytometry analysis for microalgal proliferation and death jointly revealed mechanisms of inhibition and subsequent self-adaptation. Results showed that exposures at 5 µg/L significantly inhibited microalgal nutrient assimilation and induced oxidative stress on day 7, with a recovery to levels comparable to the control by day 15. This self-adaptation and over 95 % removal of antibiotics jointly contributed to promoting microalgal growth and proliferation while reducing membrane-damaged cells. Under 500 µg/L SMM single-exposure, microalgae self-adapted to interferences on nutrient assimilation, maintaining unaffected growth and proliferation. However, over 60 % of SMM remained, leading to sustained oxidative stress and apoptosis. Remarkably, under 500 µg/L SMM-TMP co-exposure, the synergistic toxicity of SMM and TMP significantly impaired microalgal nutrient assimilation, reducing the degradation efficiency of SMM to about 20 %. Consequently, microalgal growth and proliferation were markedly inhibited, with rates of 9.15 % and 17.7 %, respectively, and a 1.36-fold increase in the proportion of cells with damaged membranes was observed. Sustained and severe oxidative stress was identified as the primary cause of these adverse effects. These findings shed light on the potential impacts of antibiotic mixtures at environmental concentrations on microalgae, facilitating responsible evaluation of the ecological risks of antibiotics in aquaculture ponds.


Asunto(s)
Microalgas , Estrés Oxidativo , Sulfamonometoxina , Trimetoprim , Contaminantes Químicos del Agua , Trimetoprim/toxicidad , Contaminantes Químicos del Agua/toxicidad , Microalgas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Sulfamonometoxina/toxicidad , Chlorella/efectos de los fármacos , Chlorella/metabolismo , Chlorella/crecimiento & desarrollo , Nutrientes/metabolismo , Fotosíntesis/efectos de los fármacos , Antibacterianos/toxicidad
3.
Chemosphere ; 358: 142270, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38719126

RESUMEN

To reduce the high cost of organic carbon sources in waste resource utilization in the cultivation of microalgae, volatile fatty acids (VFAs) derived from activated sludge were used as the sole carbon source to culture Chlorella sorokiniana under the heterotrophic cultivation. The addition of VFAs in the heterotrophic condition enhanced the total nitrogen (TN) and phosphorus (TP) removal of C. sorokiniana, which proved the advantageous microalgae in using VFAs in the heterotrophic culture after screening in the previous study. To discover the possible mechanism of nitrogen and phosphorus adsorption in heterotrophic conditions by microalgae, the effect of different ratios of VFAs (acetic acid (AA): propionic acid (PA): butyric acid (BA)) on the nutrient removal and growth properties of C. sorokiniana was studied. In the 8:1:1 group, the highest efficiency (77.19%) of VFAs assimilation, the highest biomass (0.80 g L-1) and lipid content (31.35%) were achieved, with the highest TN and TP removal efficiencies of 97.44 % and 91.02 %, respectively. Moreover, an aerobic denitrifying bacterium, Pseudomonas, was determined to be the dominant genus under this heterotrophic condition. This suggested that besides nitrate uptake and utilization by C. sorokiniana under the heterotrophy, the conduct of the denitrification process was also the main reason for obtaining high nitrogen removal efficiency.


Asunto(s)
Chlorella , Ácidos Grasos Volátiles , Procesos Heterotróficos , Microalgas , Nitrógeno , Fósforo , Eliminación de Residuos Líquidos , Aguas Residuales , Chlorella/metabolismo , Chlorella/crecimiento & desarrollo , Ácidos Grasos Volátiles/metabolismo , Nitrógeno/metabolismo , Microalgas/metabolismo , Aguas Residuales/química , Fósforo/metabolismo , Eliminación de Residuos Líquidos/métodos , Aguas del Alcantarillado/microbiología , Biomasa , Desnitrificación , Contaminantes Químicos del Agua/metabolismo , Biodegradación Ambiental
4.
J Nanobiotechnology ; 22(1): 227, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38711078

RESUMEN

BACKGROUND: Elevated interstitial fluid pressure within tumors, resulting from impaired lymphatic drainage, constitutes a critical barrier to effective drug penetration and therapeutic outcomes. RESULTS: In this study, based on the photosynthetic characteristics of algae, an active drug carrier (CP@ICG) derived from Chlorella pyrenoidosa (CP) was designed and constructed. Leveraging the hypoxia tropism and phototropism exhibited by CP, we achieved targeted transport of the carrier to tumor sites. Additionally, dual near-infrared (NIR) irradiation at the tumor site facilitated photosynthesis in CP, enabling the breakdown of excessive intratumoral interstitial fluid by generating oxygen from water decomposition. This process effectively reduced the interstitial pressure, thereby promoting enhanced perfusion of blood into the tumor, significantly improving deep-seated penetration of chemotherapeutic agents, and alleviating tumor hypoxia. CONCLUSIONS: CP@ICG demonstrated a combined effect of photothermal/photodynamic/starvation therapy, exhibiting excellent in vitro/in vivo anti-tumor efficacy and favorable biocompatibility. This work provides a scientific foundation for the application of microbial-enhanced intratumoral drug delivery and tumor therapy.


Asunto(s)
Chlorella , Portadores de Fármacos , Fotosíntesis , Animales , Ratones , Línea Celular Tumoral , Portadores de Fármacos/química , Humanos , Terapia Combinada , Fotoquimioterapia/métodos , Neoplasias/terapia , Antineoplásicos/farmacología , Ratones Endogámicos BALB C , Sistemas de Liberación de Medicamentos/métodos , Verde de Indocianina/farmacocinética , Verde de Indocianina/química , Femenino
5.
PLoS Biol ; 22(4): e3002563, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38573881

RESUMEN

Exploring the mechanisms that underpin symbiosis requires an understanding of how these complex interactions are maintained in diverse model systems. The ciliate protist, Paramecium bursaria, offers a valuable insight into how emergent endosymbiotic interactions have evolved.


Asunto(s)
Chlorella , Cilióforos , Paramecium , Simbiosis
6.
J Environ Manage ; 357: 120723, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38565028

RESUMEN

Due to increased pesticide usage in agriculture, a significant concentration of pesticides is reported in the environment that can directly impact humans, aquatic flora, and fauna. Utilizing microalgae-based systems for pesticide removal is becoming more popular because of their environmentally friendly nature, ability to degrade pesticide molecules into simpler, nontoxic molecules, and cost-effectiveness of the technology. Thus, this review focused on the efficiency, mechanisms, and factors governing pesticide removal using microalgae-based systems and their effect on microalgal metabolism. A wide range of pesticides, like atrazine, cypermethrin, malathion, trichlorfon, thiacloprid, etc., can be effectively removed by different microalgal strains. Some species of Chlorella, Chlamydomonas, Scenedesmus, Nostoc, etc., are documented for >90% removal of different pesticides, mainly through the biodegradation mechanism. The antioxidant enzymes such as ascorbate peroxidase, superoxide dismutase, and catalase, as well as the complex structure of microalgae cell walls, are mainly involved in eliminating pesticides and are also crucial for the defense mechanism of microalgae against reactive oxygen species. However, higher pesticide concentrations may alter the biochemical composition and gene expression associated with microalgal growth and metabolism, which may vary depending on the type of strain, the pesticide type, and the concentration. The final section of this review discussed the challenges and prospects of how microalgae can become a successful tool to remediate pesticides.


Asunto(s)
Chlorella , Microalgas , Plaguicidas , Contaminantes Químicos del Agua , Humanos , Plaguicidas/química , Microalgas/metabolismo , Contaminantes Químicos del Agua/química , Malatión/metabolismo , Malatión/farmacología
7.
J Hazard Mater ; 470: 134241, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38608594

RESUMEN

Artemisinin, a novel plant allelochemical, has attracted attention for its potential selective inhibitory effects on algae, yet to be fully explored. This study compares the sensitivity and action targets of Microcystis aeruginosa (M. aeruginosa) and Chlorella pyrenoidosa (C. pyrenoidosa) to artemisinin algaecide (AMA), highlighting their differences. Results indicate that at high concentrations, AMA displaces the natural PQ at the QB binding site within M. aeruginosa photosynthetic system, impairing the D1 protein repair function. Furthermore, AMA disrupts electron transfer from reduced ferredoxin (Fd) to NADP+ by interfering with the iron-sulfur clusters in the ferredoxin-NADP+ reductases (FNR) domain of Fd. Moreover, significant reactive oxygen species (ROS) accumulation triggers oxidative stress and interrupts the tricarboxylic acid cycle, hindering energy acquisition. Notably, AMA suppresses arginine synthesis in M. aeruginosa, leading to reduced microcystins (MCs) release. Conversely, C. pyrenoidosa counters ROS accumulation via photosynthesis protection, antioxidant defenses, and by regulating intracellular osmotic pressure, accelerating damaged protein degradation, and effectively repairing DNA for cellular detoxification. Additionally, AMA stimulates the expression of DNA replication-related genes, facilitating cell proliferation. Our finding offer a unique approach for selectively eradicating cyanobacteria while preserving beneficial algae, and shed new light on employing eco-friendly algicides with high specificity.


Asunto(s)
Artemisininas , Chlorella , Microcystis , Fotosíntesis , Especies Reactivas de Oxígeno , Microcystis/efectos de los fármacos , Microcystis/metabolismo , Chlorella/efectos de los fármacos , Chlorella/metabolismo , Artemisininas/farmacología , Fotosíntesis/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Estrés Oxidativo/efectos de los fármacos , Microcistinas/metabolismo
8.
Sci Rep ; 14(1): 8564, 2024 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-38609438

RESUMEN

The present study investigated the difference in transmittance of light carrying opposite spin angular momentum (SAM) and orbital angular momentum (OAM) through chlorella algal fluid with varying concentrations and thicknesses. Our results indicate that, under specific conditions, right-handed light sources exhibit higher transmittance in the algal fluid compared to left-handed light sources. Furthermore, we observed that light with OAM also demonstrated higher transmittance than other types of light sources, leading to faster cell density growth of Chlorella. Interestingly, we also discovered that light with OAM stimulates Chlorella to synthesize more proteins. These findings provide different insights for selecting appropriate light sources for large-scale algae cultivation, and may facilitate the realization of carbon peaking and carbon neutrality in the future.


Asunto(s)
Chlorella , Proliferación Celular , Carbono , Ciclo Celular , Mano
9.
J Hazard Mater ; 470: 134279, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38613960

RESUMEN

The application of antibiotics in freshwater aquaculture leads to increased contamination of aquatic environments. However, limited information is available on the co-metabolic biodegradation of antibiotics by microalgae in aquaculture. Feedstuffs provide multiple organic substrates for microalgae-mediated co-metabolism. Herein, we investigated the co-metabolism of sulfamethoxazole (SMX) by Chlorella pyrenoidosa when adding main components of feedstuff (glucose and lysine). Results showed that lysine had an approximately 1.5-fold stronger enhancement on microalgae-mediated co-metabolism of SMX than glucose, with the highest removal rate (68.77% ± 0.50%) observed in the 9-mM-Lys co-metabolic system. Furthermore, we incorporated reactive sites predicted by density functional theory calculations, 14 co-metabolites identified by mass spectrometry, and the roles of 18 significantly activated enzymes to reveal the catalytic reaction mechanisms underlying the microalgae-mediated co-metabolism of SMX. In lysine- and glucose-treated groups, five similar co-metabolic pathways were proposed, including bond breaking on the nucleophilic sulfur atom, ring cleavage and hydroxylation at multiple free radical reaction sites, together with acylation and glutamyl conjugation on electrophilic nitrogen atoms. Cytochrome P450, serine hydrolase, and peroxidase play crucial roles in catalyzing hydroxylation, bond breaking, and ring cleavage of SMX. These findings provide theoretical support for better utilization of microalgae-driven co-metabolism to reduce sulfonamide antibiotic residues in aquaculture.


Asunto(s)
Acuicultura , Chlorella , Glucosa , Microalgas , Sulfametoxazol , Contaminantes Químicos del Agua , Sulfametoxazol/metabolismo , Sulfametoxazol/química , Microalgas/metabolismo , Chlorella/metabolismo , Glucosa/metabolismo , Contaminantes Químicos del Agua/metabolismo , Lisina/metabolismo , Lisina/química , Biodegradación Ambiental , Redes y Vías Metabólicas , Antibacterianos/metabolismo , Antibacterianos/química
10.
BMC Genomics ; 25(1): 356, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600443

RESUMEN

BACKGROUND: Centromeres play a crucial and conserved role in cell division, although their composition and evolutionary history in green algae, the evolutionary ancestors of land plants, remains largely unknown. RESULTS: We constructed near telomere-to-telomere (T2T) assemblies for two Trebouxiophyceae species, Chlorella sorokiniana NS4-2 and Chlorella pyrenoidosa DBH, with chromosome numbers of 12 and 13, and genome sizes of 58.11 Mb and 53.41 Mb, respectively. We identified and validated their centromere sequences using CENH3 ChIP-seq and found that, similar to humans and higher plants, the centromeric CENH3 signals of green algae display a pattern of hypomethylation. Interestingly, the centromeres of both species largely comprised transposable elements, although they differed significantly in their composition. Species within the Chlorella genus display a more diverse centromere composition, with major constituents including members of the LTR/Copia, LINE/L1, and LINE/RTEX families. This is in contrast to green algae including Chlamydomonas reinhardtii, Coccomyxa subellipsoidea, and Chromochloris zofingiensis, in which centromere composition instead has a pronounced single-element composition. Moreover, we observed significant differences in the composition and structure of centromeres among chromosomes with strong collinearity within the Chlorella genus, suggesting that centromeric sequence evolves more rapidly than sequence in non-centromeric regions. CONCLUSIONS: This study not only provides high-quality genome data for comparative genomics of green algae but gives insight into the composition and evolutionary history of centromeres in early plants, laying an important foundation for further research on their evolution.


Asunto(s)
Chlorella , Humanos , Chlorella/genética , Centrómero/genética , Plantas/genética , Elementos Transponibles de ADN , Telómero/genética
11.
Environ Sci Pollut Res Int ; 31(21): 31097-31107, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38625472

RESUMEN

The cost and efficiency of an algal-BS treatment system are determined by the specific microalgal species and BS pretreatment method. This study examines the growth of a novel algae Chlorella sp. YSD-2 and the removal of nutrients from the BS using different pretreatment methods, including dilution ratio and sterilization. The highest biomass production (1.84 g L-1) was achieved in the 1:2 unsterilized biogas slurry, which was 2.03 times higher than that in the sterilized group, as well as higher lipid productivity (17.29 mg L-1 d-1). Nevertheless, the sterilized biogas slurry at a 1:1 dilution ratio exhibited the most notable nutrient-removal efficiency, with COD at 71.97%, TP at 91.32%, and TN at 88.80%. Additionally, the analysis of 16S rRNA sequencing revealed a significant alteration in the indigenous bacterial composition of the biogas slurry by microalgal treatment, with Proteobacteria and Cyanobacteria emerging as the predominant phyla, and unidentified_Cyanobacteria as the primary genus. These findings suggest that Chlorella sp. YSD-2 exhibits favorable tolerance and nutrient-removal capabilities in unsterilized, high-strength biogas slurry, along with high productivity of biomass and lipids. Consequently, these results offer a theoretical foundation for the development of an efficient and economically viable treatment method for algal-BS.


Asunto(s)
Biocombustibles , Biomasa , Microalgas , Animales , Lípidos , Chlorella/metabolismo , Porcinos , ARN Ribosómico 16S
12.
Artículo en Inglés | MEDLINE | ID: mdl-38643813

RESUMEN

Antibiotics are ubiquitously present in aquatic environments, posing a serious ecological risk to aquatic ecosystems. However, the effects of antibiotics on the photosynthetic light reactions of freshwater algae and the underlying mechanisms are relatively less understood. In this study, the effects of 4 representative antibiotics (clarithromycin, enrofloxacin, tetracycline, and sulfamethazine) on a freshwater alga (Chlorella pyrenoidosa) and the associated mechanisms, primarily focusing on key regulators of the photosynthetic light reactions, were evaluated. Algae were exposed to different concentrations of clarithromycin (0.0-0.3 mg/L), enrofloxacin (0.0-30.0 mg/L), tetracycline (0.0-10.0 mg/L), and sulfamethazine (0.0-50.0 mg/L) for 7 days. The results showed that the 4 antibiotics inhibited the growth, the photosynthetic pigment contents, and the activity of antioxidant enzymes. In addition, exposure to clarithromycin caused a 118.4 % increase in malondialdehyde (MDA) levels at 0.3 mg/L. Furthermore, the transcripts of genes for the adenosine triphosphate (ATP) - dependent chloroplast proteases (ftsH and clpP), genes in photosystem II (psbA, psbB, and psbC), genes related to ATP synthase (atpA, atpB, and atpH), and petA (related to cytochrome b6/f complex) were altered by clarithromycin. This study contributes to a better understanding of the risk of antibiotics on primary producers in aquatic environment.


Asunto(s)
Antibacterianos , Chlorella , Fotosíntesis , Contaminantes Químicos del Agua , Chlorella/efectos de los fármacos , Chlorella/metabolismo , Fotosíntesis/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Tetraciclina/farmacología , Tetraciclina/toxicidad , Claritromicina/farmacología , Enrofloxacina/farmacología , Enrofloxacina/toxicidad , Sulfametazina/toxicidad , Complejo de Proteína del Fotosistema II/metabolismo , Complejo de Proteína del Fotosistema II/efectos de los fármacos , Luz , Clorofila/metabolismo
13.
Bioresour Technol ; 401: 130714, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38641299

RESUMEN

This study established and investigated continuous macular pigment (MP) production with a lutein (L):zeaxanthin (Z) ratio of 4-5:1 by an MP-rich Chlorella sp. CN6 mutant strain in a continuous microalgal culture module. Chlorella sp. CN6 was cultured in a four-stage module for 10 days. The microalgal culture volume increased to 200 L in the first stage (6 days). Biomass productivity increased to 0.931 g/L/day with continuous indoor white light irradiation during the second stage (3 days). MP content effectively increased to 8.29 mg/g upon continuous, indoor white light and blue light-emitting diode irradiation in the third stage (1 day), and the microalgal biomass and MP concentrations were 8.88 g/L and 73.6 mg/L in the fourth stage, respectively. Using a two-step MP extraction process, 80 % of the MP was recovered with a high purity of 93 %, and its L:Z ratio was 4-5:1.


Asunto(s)
Biomasa , Chlorella , Pigmento Macular , Microalgas , Microalgas/metabolismo , Chlorella/metabolismo , Chlorella/crecimiento & desarrollo , Pigmento Macular/metabolismo , Luteína/metabolismo , Luz , Técnicas de Cultivo de Célula/métodos , Zeaxantinas/metabolismo , Xantófilas/metabolismo
14.
Bioprocess Biosyst Eng ; 47(5): 725-736, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38582779

RESUMEN

The global energy crisis has spurred a shift from conventional to clean and sustainable energy sources. Biomass derived from microalgae is emerging as an alternative energy source with diverse applications. Despite the numerous advantages of microalgae, large-scale biomass harvesting is not economical and convenient. Self-flocculation is considered an effective phenomenon facilitated by extracting the flocculating substances from microalgae that assist aggregation of algal cells into flocs. A novel cellulose-based bioflocculant has been synthesized from sewage water grown Chlorella sorokiniana and Scenedesmus abundans for harvesting application. The produced bioflocculant amounted to 38.5% and 19.38% of the dry weight of S. abundans and C. sorokiniana, respectively. Analysis via FTIR, XRD, and FESEM-EDX revealed the presence of cellulose hydroxyapatite (HA) in algae-derived cellulose. Harvesting efficiencies of 95.3% and 89.16% were attained for S. abundans and C. sorokiniana, respectively, at a dosage of 0.5 g/L. Furthermore, the bioflocculant was recovered, enabling its reuse with recovery efficiencies of 52% and 10% for S. abundans and C. sorokiniana, respectively. This simple and efficient approach has the potential to replace other harvesting methods, thereby contributing to the economic algal biofuel production.


Asunto(s)
Celulosa , Chlorella , Floculación , Scenedesmus , Aguas del Alcantarillado , Chlorella/crecimiento & desarrollo , Chlorella/metabolismo , Scenedesmus/crecimiento & desarrollo , Scenedesmus/metabolismo , Celulosa/química , Biomasa , Microalgas/crecimiento & desarrollo , Microalgas/metabolismo
15.
Sci Total Environ ; 931: 172567, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38643871

RESUMEN

Microalgal polysaccharides have received much attention due to their potential value in preventing and regulating oxidative damage. This study aims to reveal the mechanisms of regulating oxidative stress and the differences in the yield, structure, and effect of polysaccharides extracted from three microalgae: Golenkinia sp. polysaccharides (GPS), Chlorella sorokiniana polysaccharides (CPS), and Spirulina subsalsa polysaccharides (SPS). Using the same extraction method, GPS, CPS, and SPS were all heteropoly- saccharides composed of small molecular fraction: the monosaccharides mainly comprised galactose (Gal). Among the three, SPS had a higher proportion of small molecular fraction, and a higher proportion of Gal; thus it had the highest yield and antioxidant activity. GPS, CPS, and SPS all showed strong antioxidant activity in vitro, and showed strong ability to regulate oxidative stress, among which SPS was slightly higher. From the analysis of gene expression, the Nrf2-ARE signalling pathway was an important pathway for GPS, CPS, and SPS to regulate cellular oxidative stress. This study provides a theoretical foundation for further research on the utilization of microalgae polysaccharides and product development.


Asunto(s)
Antioxidantes , Chlorella , Microalgas , Estrés Oxidativo , Polisacáridos , Polisacáridos/farmacología , Polisacáridos/química , Estrés Oxidativo/efectos de los fármacos , Spirulina/química
16.
Aquat Toxicol ; 271: 106922, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38615581

RESUMEN

The photodegradation products (PDPs) of antibiotics in the aquatic environment received increasing concern, but their chronic effects on microalgae remain unclear. This study initially focused on examining the acute effects of erythromycin (ERY), then explored the chronic impacts of ERY PDPs on Chlorella pyrenoidosa. ERY of 4.0 - 32 mg/L ERY notably inhibited the cell growth and chlorophyll synthesis. The determined 96 h median effective concentration of ERY to C. pyrenoidosa was 11.78 mg/L. Higher concentrations of ERY induced more serious oxidative damage, antioxidant enzymes alleviated the oxidative stress. 6 PDPs (PDP749, PDP747, PDP719, PDP715, PDP701 and PDP557) were identified in the photodegradation process of ERY. The predicted combined toxicity of PDPs increased in the first 3 h, then decreased. Chronic exposure showed a gradual decreasing inhibition on microalgae growth and chlorophyll content. The acute effect of ERY PDPs manifested as growth stimulation, but the chronic effect manifested as growth inhibition. The malonaldehyde contents decreased with the degradation time of ERY at 7, 14 and 21 d. However, the malonaldehyde contents of ERY PDPs treatments were elevated compared to those in the control group after 21 d. Risk assessment still need to consider the potential toxicity of degradation products under long-term exposure.


Asunto(s)
Chlorella , Clorofila , Eritromicina , Microalgas , Fotólisis , Contaminantes Químicos del Agua , Chlorella/efectos de los fármacos , Chlorella/efectos de la radiación , Eritromicina/toxicidad , Eritromicina/farmacología , Contaminantes Químicos del Agua/toxicidad , Microalgas/efectos de los fármacos , Clorofila/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/efectos de la radiación , Antibacterianos/toxicidad , Antibacterianos/farmacología , Malondialdehído/metabolismo
17.
Arch Microbiol ; 206(5): 218, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38625565

RESUMEN

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-D-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography-mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-D-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL-1 with IC50 equal to 4.31 ± 0.20 mg mL-1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive.


Asunto(s)
Chlorella , Sulfatos , Ecosistema , Arabinosa , Glucosidasas
18.
Bioresour Technol ; 400: 130697, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38614145

RESUMEN

Effects of a phosphorus-solubilizing bacteria (PSB) Bacillus megatherium on growth and lipid production of Chlorella sorokiniana were investigated in synthesized swine wastewater with dissolved inorganic phosphorus (DIP), insoluble inorganic phosphorus (IIP), and organic phosphorus (OP). The results showed that the PSB significantly promoted the algal growth in OP and IIP, by 1.10 and 1.78-fold, respectively. The algal lipid accumulation was also greatly triggered, respectively by 4.39, 1.68, and 1.38-fold in DIP, IIP, and OP. Moreover, compared with DIP, OP improved the oxidation stability of algal lipid by increasing the proportion of saturated fatty acids (43.8 % vs 27.9 %), while the PSB tended to adjust it to moderate ranges (30.2-41.6 %). Further, the transcriptome analysis verified the OP and/or PSB-induced up-regulated genes involving photosynthesis, lipid metabolism, signal transduction, etc. This study provided novel insights to enhance microalgae-based nutrient removal combined with biofuel production in practical wastewater, especially with complex forms of phosphorus.


Asunto(s)
Chlorella , Lípidos , Fosfatos , Aguas Residuales , Aguas Residuales/microbiología , Animales , Chlorella/metabolismo , Chlorella/crecimiento & desarrollo , Porcinos , Fosfatos/metabolismo , Lípidos/biosíntesis , Fósforo/metabolismo , Metabolismo de los Lípidos , Solubilidad , Bacillus/metabolismo
19.
Bioresour Technol ; 400: 130651, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38570100

RESUMEN

Excessive proliferation of algae in water depletes dissolved oxygen, resulting in the demise of aquatic life and environmental damage. This study delves into the effectiveness of the dielectric barrier discharge (DBD) plasma activated peracetic acid (PAA) system in deactivating Chlorella. Within 15 min, the algae removal effectiveness reached 89 % under ideal trial conditions. DBD plasma activation of PAA augmented the concentration of reactive species such as ·OH, 1O2, and organic radicals (RO·) in the solution, which are involved in the process of cell inactivation. Reactive oxygen species (ROS) within Chlorella cells continued to rise as a result of treatment-induced damage to the morphological structure and cell membrane of the organism. DNA and chlorophyll-a (Chl-a), were oxidized and destroyed by these invasive active compounds. This study presents an efficient advanced oxidation method to destroy algal cells and adds an alternative strategy for algal control in areas where eutrophication occurs.


Asunto(s)
Chlorella , Ácido Peracético , Gases em Plasma , Especies Reactivas de Oxígeno , Chlorella/metabolismo , Chlorella/efectos de los fármacos , Ácido Peracético/farmacología , Gases em Plasma/farmacología , Especies Reactivas de Oxígeno/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo
20.
Bioresour Technol ; 400: 130668, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38583677

RESUMEN

This study examined the removal of typical antibiotics from simulated swine wastewater. Microalgae-bacteria/fungi symbioses were constructed using Chlorella ellipsoidea, endophytic bacteria (S395-2), and Clonostachys rosea as biomaterials. The growth, photosynthetic performance, and removal of three types of antibiotics (tetracyclines, sulfonamides, and quinolones) induced by four phytohormones were analyzed in each system. The results showed that all four phytohormones effectively improved the tolerance of symbiotic strains against antibiotic stress; strigolactones (GR24) achieved the best performance. At 10-9 M, GR24 achieved the best removal of antibiotics by C. elliptica + S395-2 + C. rosea symbiosis. The average removals of tetracycline, sulfonamide, and quinolone by this system reached 96.2-99.4 %, 75.2-81.1 %, and 66.8-69.9 %, respectively. The results of this study help to develop appropriate bio enhancement strategies as well as design and operate algal-bacterial-fungal symbiotic processes for the treatment of antibiotics-containing wastewater.


Asunto(s)
Antibacterianos , Microalgas , Reguladores del Crecimiento de las Plantas , Aguas Residuales , Purificación del Agua , Animales , Microalgas/efectos de los fármacos , Aguas Residuales/química , Antibacterianos/farmacología , Porcinos , Purificación del Agua/métodos , Reguladores del Crecimiento de las Plantas/farmacología , Contaminantes Químicos del Agua , Simbiosis/efectos de los fármacos , Biodegradación Ambiental , Fotosíntesis/efectos de los fármacos , Chlorella/efectos de los fármacos
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