Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Control Release ; 372: 446-466, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38917953

RESUMO

Cancer immunotherapy remains a significant challenge due to insufficient proliferation of immune cells and the sturdy immunosuppressive tumor microenvironment. Herein, we proposed the hypothesis of cuproptosis-lactate regulation to provoke cuproptosis and enhance anti-tumor immunity. For this purpose, copper-human serum albumin nanocomplex loaded gold nanocages with bacterial membrane coating (BAu-CuNCs) were developed. The targeted delivery and disassembly of BAu-CuNCs in tumor cells initiated a cascade of reactions. Under near infrared (NIR) laser irradiation, the release of copper-human serum albumin (Cu-HSA) was enhanced that reacted with intratumoral glutathione (GSH) via a disulfide exchange reaction to liberate Cu2+ ions and exert cuproptosis. Subsequently, the cuproptosis effect triggered immunogenic cell death (ICD) in tumor by the release of damage associated molecular patterns (DAMPs) to realize anti-tumor immunity via robust production of cytotoxic T cells (CD8+) and helper T cells (CD4+). Meanwhile, under NIR irradiation, gold nanocages (AuNCs) promoted excessive reactive oxygen species (ROS) generation that played a primary role in inhibiting glycolysis, reducing the lactate and ATP level. The combine action of lower lactate level, ATP reduction and GSH depletion further sensitized the tumor cells to cuproptosis. Also, the lower lactate production led to the significant blockage of immunosuppressive T regulatory cells (Tregs) and boosted the anti-tumor immunity. Additionally, the effective inhibition of breast cancer metastasis to the lungs enhanced the anti-tumor therapeutic impact of BAu-CuNCs + NIR treatment. Hence, BAu-CuNCs + NIR concurrently induced cuproptosis, ICD and hindered lactate production, leading to the inhibition of tumor growth, remodeling of the immunosuppressive tumor microenvironment and suppression of lung metastasis. Therefore, leveraging cuproptosis-lactate regulation, this approach presents a novel strategy for enhanced tumor immunotherapy.

2.
Inorg Chem ; 63(1): 677-688, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38109074

RESUMO

The abuse of antibiotics leads to an increasing emergence of drug-resistant bacteria, which not only causes a waste of medical resources but also seriously endangers people's health and life safety. Therefore, it is highly desirable to develop an efficient antibacterial strategy to reduce the reliance on traditional antibiotics. Antibacterial photodynamic therapy (aPDT) is regarded as an intriguing antimicrobial method that is less likely to generate drug resistance, but its efficiency still needs to be further improved. Herein, a robust titanium-based metal-organic framework ACM-1 was adopted to support Ag nanoparticles (NPs) to obtain Ag NPs@ACM-1 for boosting antibacterial efficiency via synergistic chemical-photodynamic therapy. Apart from the intrinsic antibacterial nature, Ag NPs largely boost ROS production and thus improve aPDT efficacy. As a consequence, Ag NPs@ACM-1 shows excellent antibacterial activity under visible light illumination, and its minimum bactericidal concentrations (MBCs) against E. coli, S. aureus, and MRSA are as low as 39.1, 39.1, and 62.5 µg mL-1, respectively. Moreover, to expand the practicability of Ag NPs@ACM-1, two (a dense and a loose) Ag NPs@ACM-1 films were readily fabricated by simply dispersing Ag NPs@ACM-1 into heated aqueous solutions of edible agar and sequentially cooling through heating or freeze-drying, respectively. Notably, these two films are mechanically flexible and exhibit excellent antibacterial activities, and their antimicrobial performances can be well retained in their recyclable and remade films. As agar is nontoxic, degradable, inexpensive, and ecosustainable, the dense and loose Ag NPs@ACM-1 films are potent to serve as recyclable and degradable antibacterial plastics and antibacterial dressings, respectively.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Estruturas Metalorgânicas , Fotoquimioterapia , Humanos , Prata/farmacologia , Titânio/farmacologia , Estruturas Metalorgânicas/farmacologia , Staphylococcus aureus , Escherichia coli , Ágar , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana
3.
Front Immunol ; 13: 985187, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36248860

RESUMO

Cancer recurrence and chemoresistance are the leading causes of death in high-grade serous ovarian cancer (HGSOC) patients. However, the unique role of the immune environment in tumor progression for relapsed chemo-resistant patients remains elusive. In single-cell resolution, we characterized a comprehensive multi-dimensional cellular and immunological atlas from tumor, ascites, and peripheral blood of a chemo-resistant patient at different stages of treatment. Our results highlight a role in recurrence and chemoresistance of the immunosuppressive microenvironment in ascites, including MDSC-like myeloid and hypo-metabolic γδT cells, and of peripheral CD8+ effector T cells with chemotherapy-induced senescent/exhaustive. Importantly, paired TCR/BCR sequencing demonstrated relative conservation of TCR clonal expansion in hyper-expanded CD8+ T cells and extensive BCR clonal expansion without usage bias of V(D)J genes after chemotherapy. Thus, our study suggests strategies for ameliorating chemotherapy-induced immune impairment to improve the clinical outcome of HGSOC.


Assuntos
Antineoplásicos , Neoplasias Ovarianas , Antineoplásicos/uso terapêutico , Ascite , Linfócitos T CD8-Positivos , Carcinoma Epitelial do Ovário , Feminino , Humanos , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Receptores de Antígenos de Linfócitos T/genética , Microambiente Tumoral/genética
4.
Artigo em Inglês | MEDLINE | ID: mdl-35564638

RESUMO

Tea is the main commercial crop grown in China, and excessive application of chemical fertilizers in tea plantations is common. However, the potential to reduce chemical fertilizer use in tea plantations is unclear. In this study, Zhejiang Province was selected as the research object to systematically analyze the potential for tea plantation chemical-fertilizer reduction at different spatial scales. The geographic information system-based analytic hierarchy process method and Soil and Water Assessment Tool model were used to determine the chemical fertilizer reduction potential at the province scale and watershed scale, respectively. At the field scale, two consecutive years of field experiments were conducted on a tea plantation. Province-level analysis showed that 51.7% of the area had an average total fertilization intensity greater than 350 kg/hm2 and a high reduction potential. Watershed analysis revealed that chemical fertilizer reduction had better potential in reducing total nitrogen and total phosphorus inputs to runoff in the short term, whereas 50% organic fertilizer substitution was the best strategy to achieve long-term effects. The field experiments further proved that organic fertilizer substitution balanced tea growth and environmental protection. This study provides a useful method to investigate strategies to reduce chemical fertilizer use in tea-growing areas.


Assuntos
Fertilizantes , Nitrogênio , Agricultura , China , Fertilizantes/análise , Nitrogênio/análise , Fósforo/análise , Solo , Chá
5.
Fish Shellfish Immunol ; 124: 313-323, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35421574

RESUMO

Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) that play a critical role in innate immune responses against pathogens. In the present study, a fish-specific TLR14 was identified and characterized from Monopterus albus (named MaTLR14), which consisted of a 2658 bp open reading frame encoding a protein of 885 amino acids. Phylogenetic analysis revealed that MaTLR14 belong to the TLR1 subfamily and shared the highest similarity to Paralichthys olivaceus TLR14. Immunohistochemistry assay showed that MaTLR14 mainly located in intestinal epithelial cells of hindgut. Immunofluorescence revealed that MaTLR14 largely localized to the intracellular region and partially co-localized with cell membrane of HeLa cells. The expression levels of MaTLR14 were upregulated in the liver, spleen, foregut and hindgut post infection with Aeromonas hydrophila. When stimulated with LPS and Flagellin, the MaTLR14 expression was elevated in isolated peripheral blood leukocytes. Further studies showed that recombinant MaTLR14-LRR could bind to both the gram-negative and gram-positive bacteria and cause agglutination. Subsequently, the signaling pathway of MaTLR14 was investigated. Confocal microscopy and co-immunoprecipitation assay demonstrated that MaTLR14 recruited MyD88 as adaptor. When overexpressed, MaTLR14 augmented the expression of TRAF6 and phosphorylation of ERK and p65, activated NF-κB and AP-1 and elicited the expression of il-6 and tnf-α. Collectively, MaTLR14 plays an important role in the microorganism recognition and signaling transduction.


Assuntos
Infecções Bacterianas , Doenças dos Peixes , Proteínas de Peixes , Smegmamorpha , Receptores Toll-Like , Sequência de Aminoácidos , Animais , Infecções Bacterianas/imunologia , Infecções Bacterianas/veterinária , Doenças dos Peixes/imunologia , Doenças dos Peixes/microbiologia , Proteínas de Peixes/imunologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Células HeLa , Humanos , Imunidade Inata/genética , Filogenia , Smegmamorpha/imunologia , Receptores Toll-Like/imunologia
6.
Vet Res ; 52(1): 88, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34130754

RESUMO

Toll-like receptor 19 (Tlr19) is a fish-specific TLR that plays a critical role in innate immunity. In the present study, we aimed to identify tlr19 from common carp (Cyprinus carpio L.) and explored its expression profile, localization, adaptor, and signaling pathways. A novel tlr19 cDNA sequence (Cctlr19) was identified in common carp. Phylogenetic analysis revealed that CcTlr19 was most closely related to Danio rerio Tlr19. Subcellular localization analysis indicates that CcTlr19 was synthesized in the free ribosome and then transported to early endosomes. Cctlr19 was constitutively expressed in all the examined tissues, with the highest expression in the brain. After poly(I:C) and Aeromonas hydrophila injection, the expression of Cctlr19 was significantly upregulated in immune-related organs. In addition, the expression of Cctlr19 was upregulated in head kidney leukocytes (HKL) upon stimulation with different ligands. Immunofluorescence and luciferase analyses indicate that CcTlr19 recruited TRIF as an adaptor. Furthermore, CcTlr19 can activate the expression of ifn-1 and viperin. Taken together, these findings lay the foundation for future research to investigate the mechanisms underlying fish tlr19.


Assuntos
Carpas/genética , Carpas/imunologia , Doenças dos Peixes/imunologia , Regulação da Expressão Gênica/imunologia , Imunidade Inata/genética , Receptores Toll-Like/genética , Receptores Toll-Like/imunologia , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Aeromonas hydrophila , Animais , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/imunologia , Perfilação da Expressão Gênica/veterinária , Infecções por Bactérias Gram-Negativas , Interferons/genética , Filogenia , Poli I-C , Análise de Sequência de DNA/veterinária , Transdução de Sinais , Receptores Toll-Like/química
7.
Sci Total Environ ; 762: 143059, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33477247

RESUMO

Carbon (C) and nitrogen (N) inputs to farmland via fertilizer application are potential sources of C and N that influence soil acidification and water eutrophication. A pilot study was conducted to compare the effects of compound fertilizer and rapeseed cake organic fertilizer on C and N preservation in the soils and runoff of a tea plantation as well as the C and N isotopic fractionation in soils over the three annual cycles of fertilization and tea-leaf harvest. Overall, rapeseed cake organic fertilization effectively increased the pH, total organic matter, NH4-N and NO3-N in soils by 2.19-4.29%, 8.04-21.14%, 53.65-100.32% and 5.74-54.08%, respectively, but decreased NH4-N inputs in runoff by 10.36-25.12% and NO3-N inputs in runoff by 8.94-24.10% relative to the same rate of pure N in compound fertilizer. Before fertilization in February, the average δ13C and δ15N were -25.15‰ and 1.88‰, while after a full year of fertilization and tea-leaf harvesting in October, the average soil δ13C and δ15N contents were -23.83‰ and -0.33‰ after compound fertilization and -26.22‰ and 1.64‰ after rapeseed cake organic fertilization, respectively, indicating the evident effects of fertilization on the isotopic fractionation in soil. In addition, the fractionation extent was positively associated with the fertilization rates under both fertilizers. However, the two fertilization types had different effects on the C and N isotope fractionations, with rapeseed cake organic fertilization contributing more to δ13C (21.07-81.80%) but less to δ15N (18.20-78.93%) and compound fertilization presenting the opposite results (1.88-46.18% and 53.82-98.12%, respectively). This study demonstrates that rapeseed cake organic fertilization can better preserve soil C and N pools while reducing their runoff in tea plantations, which may greatly hinder the regional soil acidification and water eutrophication trends.

8.
Sci Total Environ ; 726: 138550, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304946

RESUMO

The bioaccumulation and trophic transfer of As along food webs in freshwater ecosystems remain largely unknown. In this study, multiple environmental and biological samples were collected from a closed realgar mining area in South China. The As concentrations in the surface water, sediments and soils in the mining area were 0.62-3293 µg/L, 9.53-4543 mg/kg and 7.32-5008 mg/kg, respectively, and gradually decreased with distance from the central mining sites, indicating that historic As mining activities had an eminent impact on As contamination around the mine. The As concentrations in aquatic organisms ranged from 0.60 mg/kg to 45.75 mg/kg and varied markedly among sites and species, reflecting the influence of various physiologic and environmental factors. Arsenic species identified by liquid chromatography inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) were mainly organic, comprising 8% to 66% of the total As. Both the proportions and concentrations of inorganic As were positively correlated with total As. This correlation could be attributed to the higher assimilation and accumulation of inorganic As or the lower biotransformation ability of inorganic As with the increasing total As in the studied organisms. Values of δ13C and δ15N in aquatic organisms ranged from -30.59‰ to -15.07‰ and from 4.31‰ to 12.98‰, respectively, indicating multiple trophic levels and variety in the diet sources of these organisms. The δ15N increased distinctly in the order of planktivorous

Assuntos
Arsênio/análise , Poluentes Químicos da Água/análise , Animais , Organismos Aquáticos , Arsenicais , Bioacumulação , China , Ecossistema , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Isótopos , Sulfetos
9.
Fish Shellfish Immunol ; 95: 25-34, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31610289

RESUMO

p65 is an important subunit of the transcription factor NF-κB in the regulation of immune response. In the present study, the p65 cDNA was identified from common carp (Cyprinus carpio L.) (named Ccp65). Phylogenetic analysis revealed that Ccp65 located in the same clade as piscine p65 and exhibited closest relationship to that of Ctenopharyngodon idella. Ccp65 was constitutively expressed in all the examined tissues. Aeromonas hydrophila and poly(I:C) can induce the expression of Ccp65 in the designated tissues and the Ccp65 expression was up-regulated in HKLs following LPS and poly(I:C) stimulation. In addition, the nuclear localization signal (NLS) and C-terminal domain are the important elements of Ccp65. Immunofluorescence assay revealed that the nuclear localization signal deletion mutation of Ccp65 (Ccp65ΔNLS) failed to translocate to the nucleus even though stimulation with poly(I:C) or LPS, and the C-terminal domain deletion mutation of Ccp65 (Ccp65ΔC) did not up-regulate the luciferase activity. Furthermore, Ccp65 can induce the expression of il-1ß and tnf-α. And LPS and poly(I:C) inducing the expression of il-1ß and tnf-α, is dependent on the Ccp65. Taken altogether, these findings lay the foundations for future research to investigate the mechanisms underlying fish p65.


Assuntos
Carpas/metabolismo , Proteínas de Peixes/genética , Imunidade Inata , Fator de Transcrição RelA/genética , Fator de Transcrição RelA/metabolismo , Aeromonas hydrophila , Animais , Carpas/genética , Carpas/imunologia , Suplementos Nutricionais/análise , Proteínas de Peixes/metabolismo , Expressão Gênica/imunologia , Interleucina-1beta/metabolismo , Filogenia , Poli I-C/farmacologia , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo
10.
Environ Manage ; 64(3): 366-380, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31377846

RESUMO

To obtain a general understanding of heavy metal contamination in peri-urban agricultural soils in China, this study investigates the concentrations of eight heavy metals, i.e., Cd, Pb, Zn, As, Cu, Cr, Hg, and Ni, in the peri-urban agricultural soils of 31 provincial capital cities in China. The data were obtained via exhaustive literature searches in both the Web of Science and China National Knowledge Infrastructure (CNKI) as well as from statistical yearbooks published in China. To evaluate the pollution status of each city and identify a variety of potential sources, various contamination indexes, e.g., the enrichment factor (EF), geoaccumulation index (Igeo), and integrated pollution index (IPI), were calculated based on the peri-urban agricultural soil dataset. The results of the analysis of the heavy metal concentrations, EF values and Igeo values showed that the peri-urban agricultural soils were enriched in most heavy metals, and Cd and Hg concentrations greatly exceeded the Chinese Environmental Protection Administration (CEPA) guidelines. The IPI results showed that 15 of the 31 cities, i.e., 48%, exhibited varying extents of heavy metal pollution. Although the mean IPI value for peri-urban agricultural soils in all cities (0.83) was slightly lower than that for urban soil (0.9), the IPI values for peri-urban agricultural soils from 65% of the cities were greater than those for urban soils, indicating that peri-urban agricultural soils are more polluted than urban soils in these large cities. These results are important for guiding future research on heavy metal pollution in peri-urban agricultural soils of presently expanding Chinese cities.


Assuntos
Metais Pesados , Poluentes do Solo , China , Cidades , Monitoramento Ambiental , Medição de Risco , Solo
11.
J Fish Biol ; 95(2): 510-519, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31059592

RESUMO

In the present study, interferon (IFN) regulatory factor (IRF) 9 gene (irf9) was identified and characterized in common carp Cyprinus carpio. The predicted protein sequence of Irf9 contains a DNA binding domain (DBD) that possess five tryptophans, an IRF association domain (IAD) and two nuclear localisation signals (NLS). Alignment of Irf9 of C. carpio with the corresponding Irf9 proteins of other species showed that the DBD is more highly conserved than the IAD. The putative Irf9 protein sequence of C. carpio shares higher identities with teleosts (53.8-82.3%) and lower identities with mammals (30.2-31.0%). Phylogenetic studies of the putative amino-acid sequence of IRF9 based on the neighbour-joining method showed that Irf9 of C. carpio has the closest relationship with the grass carp Ctenopharyngodon idella. Tissue distribution analysis showed that irf9 transcripts were detectable in all examined tissues with the highest expression in the skin and the lowest expression in the head kidney. Poly I:C and Aeromonas hydrophila stimulation up-regulated irf9 expression in the spleen, head kidney, foregut and hindgut at different time intervals. In addition, irf9 was induced by Poly I:C and lipopolysaccharides (LPS) in vitro. These results indicate that Irf9 participates in antiviral and antibacterial immunity. Transfection of irf9 up-regulated the expression of cytokines, including type I IFN, protein kinase R (PKR), interferon-stimulated gene (ISG)15 and tumour necrosis factor (TNF)α in epithelioma papulosum cyprini cells (EPC) upon poly I:C and LPS stimulation. A dual-luciferase reporter assay revealed that Irf9 has no effect on NF-κB activation. The present study on Irf9 provides new insights into the IFN system of C. carpio and a valuable experimental platform for future studies on the immune system of fish.


Assuntos
Carpas/imunologia , Proteínas de Peixes/fisiologia , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/fisiologia , Sequência de Aminoácidos , Animais , Carpas/metabolismo , Carpas/microbiologia , Doenças dos Peixes/imunologia , Proteínas de Peixes/química , Proteínas de Peixes/metabolismo , Rim Cefálico/metabolismo , Interações Hospedeiro-Patógeno , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/química , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/metabolismo , Filogenia
12.
Environ Sci Pollut Res Int ; 26(3): 2464-2476, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30471060

RESUMO

Tea tree (Camellia sinensis) is a valuable and popular cash crop widely planted in tropical and subtropical areas of China. To increase tea yield and quality, high rates of chemical fertilizer and pesticide application have generally been used; however, increasing usage of fertilizers and pesticides does not always proportionally increase tea yield. Indeed, excessive nutrient inputs may cause serious agricultural non-point source pollution. A pilot study on dual reduction in fertilizers and pesticides was conducted in a green tea plantation in Shaoxing, Zhejiang Province, to explore the environmental effects of different fertilizer and pesticide managements (e.g., changes in soil properties and nutrient accumulation, nutrient inputs in runoff water) and to reveal the potential effects of the interaction of these two managements on tea yield and quality. Traditional formulas and rates of chemical fertilizers and pesticides were used as the baselines (100% usage); replacement with different proportions of organic fertilizer (i.e., 20%, 50% and 80%) and direct pesticide reductions of 30%, 50%, and 80% were tested. The results showed that proper management with organic fertilizer replacement can effectively mitigate soil acidification and nutrient deficiency in tea plantations, increase soil organic matter (OM) and ammonium nitrogen (NH4-N) contents, and promote tea yield and quality. Moreover, managements with organic fertilizer replacement can markedly reduce the inputs of ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), total phosphorus (TP), and total potassium (TK) in runoff water. Soil nutrient accumulation was the highest while the runoff nutrient input was the lowest at 20% organic fertilizer replacement. Experimental spraying of bifenthrin and chlorfenapyr revealed that these pesticides were mainly trapped by the tea leaves and rarely entered the soil or water bodies. Although pesticide reduction treatments can effectively decrease pesticide residues in tea leaves, differences in pesticide residue between various treatments were not obvious due to the rapid degradation of pesticides. Multivariate analysis of variance showed that 50% of the variation in tea yield, bud density, polyphenols, and caffeine can be explained by interactions between fertilizers and pesticides. Combinations of 20% or 50% organic fertilizer replacement and 30% or 50% pesticide application reduction are appropriate for both mitigating nutrient loss and balancing tea yield and quality, especially the combination of 50% organic fertilizer replacement and 50% pesticide reduction, which produced the best results. This study demonstrates the feasibility of dual reductions in fertilizers and pesticides for mitigating environmental hazards while maintaining the yield and quality of tea.


Assuntos
Camellia sinensis/metabolismo , Produção Agrícola/métodos , Fertilizantes/análise , Praguicidas/análise , Camellia sinensis/química , Camellia sinensis/efeitos dos fármacos , Camellia sinensis/crescimento & desenvolvimento , China , Nitratos/análise , Nitratos/metabolismo , Nitrogênio/análise , Nitrogênio/metabolismo , Nutrientes/metabolismo , Praguicidas/farmacologia , Fósforo/análise , Fósforo/metabolismo , Projetos Piloto , Potássio/análise , Potássio/metabolismo , Solo/química , Chá/química
13.
Environ Sci Pollut Res Int ; 25(20): 19413-19422, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29728971

RESUMO

This study was carried out using indoor controlled experiments to study the arsenic (As) uptake, biotransformation, and release behaviors of freshwater algae under growth stress. Three freshwater algae, Microcystis aeruginosa, Anabaena flosaquae, and Chlorella sp., were chosen. Two types of inhibitors, e.g., Cu2+ and isothiazolinone, were employed to inhibit the growth of the algae. The algae were cultivated to a logarithmic stage in growth media containing 0.1 mg/L P; then, 0.8 mg/L As in the form of arsenate (iAsV) was added, while both inhibitors were simultaneously added at dosages of 0.1 and 0.3 mg/L, with no addition of inhibitors in the control. After 2 days of exposure, the average growth rate (µ2d) was measured to represent the growth rates of the algae cells; the extra- and intracellular As concentrations in various forms, i.e., arsenate, arsenite (iAsIII), monomethyl arsenic (MMA), and dimethyl arsenic (DMA), were also measured. Without inhibitors, the average growth rate followed the order of M. aeruginosa, Chlorella sp., and A. flosaquae, with the growth rate of M. aeruginosa significantly higher than that of the other two algae. However, when Cu2+ was added as an external inhibitor, the order of the average growth rate for the three algae became partially reversed, suggesting differentiation of the algae in response to the inhibitor. This differentiation can be seen by the reduction in the average growth rate of M. aeruginosa, which was as high as 1730% at the 0.3-mg/L Cu2+ dosage when compared with the control, while for the other two algae, much fewer changes were seen. The great reduction in M. aeruginosa growth rate was accompanied by increases in extracellular iAsV and iAsIII and intracellular iAsV concentrations in the algae, indicating that As transformation is related to the growth of this algae. Much fewer or neglectable changes in growth were observed that were consistent with the few changes in the extra- and intracellular As speciation for the other two algae with Cu2+ inhibition and all the three algae with isothiazolinone inhibition, corroborating the above hypothesis again. All the algae tested in this study demonstrated great abilities for As transformation and release, as seen by the much higher rates of 86.11-99.98% and 81.11-99.89% for transformation and release when compared to the control, respectively. When inhibitors were added, the transformation and release values of only A. flosaquae decreased remarkably down to 72.37-86.79% and 64.67-85.24%, respectively, while no changes were seen for these values in the other two algae, indicating that growth stress did not affect the As transformation and release of the other algae. The biological productivity of As by the three algae followed the order of M. aeruginosa, Chlorella sp., and A. flosaquae, which was generally consistent with the As transformation and release in conditions with and without inhibitors, suggesting that the As behavior in the algae that was related to growth stress largely differed among algae species.


Assuntos
Anabaena/fisiologia , Organismos Aquáticos/fisiologia , Arsenicais/metabolismo , Chlorella/fisiologia , Microcystis/fisiologia , Estresse Fisiológico/fisiologia , Anabaena/crescimento & desenvolvimento , Anabaena/metabolismo , Organismos Aquáticos/crescimento & desenvolvimento , Organismos Aquáticos/metabolismo , Biotransformação/fisiologia , Chlorella/crescimento & desenvolvimento , Chlorella/metabolismo , Água Doce , Microcystis/crescimento & desenvolvimento , Microcystis/metabolismo , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...