RESUMO
Harmful algal blooms have deleterious effects on aquatic ecosystems and human health. The application of algicidal bacteria is a promising and environmentally friendly method of preventing and eradicating harmful algal blooms. In this study, a screen for algicidal agents against harmful algal blooms was used to identify an algicidal bacterial strain (strain O-4) isolated from a Karenia mikimotoi culture. Strain O-4 exhibited a strong inhibitory effect on harmful K. mikimotoi and was identified as Paracoccus homiensis via 16S rRNA gene sequence analysis. This strain killed K. mikimotoi by secreting active algicidal compounds, which were stable at temperatures of -80-121 °C but were sensitive to strongly acidic conditions (pH = 2). The algicidal properties of strain O-4 against K. mikimotoi were cell density- and time-dependent. No significant changes or negative effects were noted for two other Chlorophyta species, which highlighted the specificity of the studied algicidal substance. Finally, single-factor experiments revealed the optimum growth conditions of strain O-4 under different pH and temperature conditions. Therefore, strain O-4 has the potential to be used as a bio-agent for reducing the biomass of harmful K. mikimotoi blooms.
Assuntos
Dinoflagellida , Proliferação Nociva de Algas , Bactérias , Ecossistema , Humanos , Paracoccus , RNA Ribossômico 16S/genética , Microbiologia da ÁguaRESUMO
Activation of the Ca2+/calmodulin-dependent protein kinase II isoform δA (CaMKIIδA) disturbs intracellular Ca2+ homeostasis in cardiomyocytes during chronic heart failure (CHF). We hypothesized that upregulation of CaMKIIδA in cardiomyocytes might enhance Ca2+ leak from the sarcoplasmic reticulum (SR) via activation of phosphorylated ryanodine receptor type 2 (P-RyR2) and decrease Ca2+ uptake by inhibition of SR calcium ATPase 2a (SERCA2a). In this study, CHF was induced in rats by ligation of the left anterior descending coronary artery. We found that CHF caused an increase in the expression of CaMKIIδA and P-RyR2 in the left ventricle (LV). The role of CaMKIIδA in regulation of P-RyR2 was elucidated in cardiomyocytes isolated from neonatal rats in vitro. Hypoxia induced upregulation of CaMKIIδA and activation of P-RyR2 in the cardiomyocytes, which both were attenuated by knockdown of CaMKIIδA. Furthermore, we showed that knockdown of CaMKIIδA significantly decreased the Ca2+ leak from the SR elicited by hypoxia in the cardiomyocytes. In addition, CHF also induced a downregulation of SERCA2a in the LV of CHF rats. Knockdown of CaMKIIδA normalized hypoxia-induced downregulation of SERCA2a in cardiomyocytes in vitro. The results demonstrate that the inhibition of CaMKIIδA may improve cardiac function by preventing SR Ca2+ leak through downregulation of P-RyR2 and upregulation of SERCA2a expression in cardiomyocytes in CHF.
Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cálcio/metabolismo , Insuficiência Cardíaca/metabolismo , Miócitos Cardíacos/metabolismo , Retículo Sarcoplasmático/metabolismo , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Masculino , Ratos Sprague-Dawley , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Regulação para CimaRESUMO
The authors describe a molecular beacon-based fluorescent probe for the determination of the cancer drug bleomycin (BLM). The probe was tagged with DNA-templated silver nanoclusters (DNA-AgNCs) and guanine-rich sequences (GRSs) at two terminals serving as signal reporter with a loop. In the absence of the BLM-iron(II) complex [BLM-Fe(II)], the probe has a hairpin shape and displays strong fluorescence because the AgNCs are close to the GRSs. In the presence of the BLM-Fe(II) complex, it will selectively cleave the probe at the 5'-GC-3' scission site of the loop. This displaces the AgNCs away from the GRSs and causes a decrease in fluorescence, best measured at excitation/emission wavelengths of 565/623 nm. This effect enables BLM to be detected with a detection limit as low as 33 pM, which was 1-3 orders of magnitude more sensitive than most of the previous reports. The probe was applied for the determination of BLM in spiked human serum samples, and excellent performance was achieved. In our perception, the method described here represents a promising tool for highly sensitive and specific analysis of BLM during cancer treatment. Graphical abstract Schematic of a highly sensitive fluorometric assay forbleomycin. It is based on molecular beacon-templated silver nanoclusters and DNA scission.
Assuntos
Bleomicina/análise , DNA/química , Corantes Fluorescentes/química , Nanopartículas Metálicas , Prata , Técnicas Biossensoriais/métodos , Bleomicina/análogos & derivados , Bleomicina/química , Complexos de Coordenação/química , Humanos , Ligantes , Limite de Detecção , Nanopartículas Metálicas/química , Espectrometria de Fluorescência/métodosRESUMO
BACKGROUND/AIMS: Flavonol (-)-epicatechin (EPI) is present in high amounts in cocoa and tea products, and has been shown to exert beneficial effects on the cardiovascular system. However, the precise mechanism of EPI on cardiomyocyte hypertrophy has not yet been determined. In this study, we examined whether EPI could inhibit cardiac hypertrophy. METHODS: We utilised cultured neonatal mouse cardiomyocytes and mice for immunofluorescence, immunochemistry, qRT-PCR, and western blot analyses. RESULTS: 1µM EPI significantly inhibited 1µM angiotensin II (Ang II)-induced increase of cardiomyocyte size, as well as the mRNA and protein levels of ANP, BNP and ß-MHC in vitro. The effects of EPI were accompanied with an up-regulation of SP1 and SIRT1, and were abolished by SP1 inhibition. Up-regulation of SP1 could block Ang II-induced increase in cardiomyocyte size, as well as the mRNA and protein levels of ANP, BNP and ß-MHC, and increase the protein levels of SIRT1 in vitro. Moreover, 1 mg/kg body weight/day EPI significantly inhibited mouse cardiac hypertrophy induced by Ang II, which could be eliminated by SP1 inhibition in vivo. CONCLUSION: Our data indicated that EPI inhibited AngII-induced cardiac hypertrophy by activating the SP1/SIRT1 signaling pathway.
Assuntos
Angiotensina II/efeitos adversos , Cardiomegalia , Catequina/farmacologia , Miócitos Cardíacos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sirtuína 1/metabolismo , Fator de Transcrição Sp1/metabolismo , Angiotensina II/farmacologia , Animais , Cardiomegalia/induzido quimicamente , Cardiomegalia/tratamento farmacológico , Cardiomegalia/metabolismo , Cardiomegalia/patologia , Camundongos , Miócitos Cardíacos/patologiaRESUMO
Evidence indicates that high salt (HS) intake activates presympathetic paraventricular nucleus (PVN) neurons, which contributes to sympathoexcitation of salt-sensitive hypertension. The present study determined whether 5 weeks of HS (2% NaCl) intake alters the small conductance Ca2+-activated potassium channel (SK) current in presympathetic PVN neurons and whether this change affects the neuronal excitability. In whole-cell voltage-clamp recordings, HS-treated rats had significantly decreased SK currents compared to rats with normal salt (NS, 0.4% NaCl) intake in PVN neurons. The sensitivity of PVN neuronal excitability in response to current injections was greater in HS group compared to NS controls. The SK channel blocker apamin augmented the neuronal excitability in both groups but had less effect on the sensitivity of the neuronal excitability in HS group compared to NS controls. In the HS group, the interspike interval (ISI) was significantly shorter than that in NS controls. Apamin significantly shortened the ISI in NS controls but had less effect in the HS group. This data suggests that HS intake reduces SK currents, which contributes to increased PVN neuronal excitability at least in part through a decrease in spike frequency adaptation and may be a precursor to the development of salt-sensitive hypertension.
Assuntos
Bulbo/fisiologia , Potenciais da Membrana , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Baixa/fisiologia , Cloreto de Sódio/administração & dosagem , Animais , Apamina/administração & dosagem , Masculino , Bulbo/efeitos dos fármacos , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Neurônios/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Ratos Sprague-Dawley , Canais de Potássio Ativados por Cálcio de Condutância Baixa/antagonistas & inibidoresRESUMO
RATIONALE: Quantitative analysis of cholesterol and its metabolic steroid hormones plays a vital role in diagnosing endocrine disorders and understanding disease progression, as well as in clinical medicine studies. Because of their extremely low abundance in body fluids, it remains a challenging task to develop a sensitive detection method. METHODS: A hyphenated technique of dual ultrasonic-assisted dispersive liquid-liquid microextraction (dual-UADLLME) coupled with microwave-assisted derivatization (MAD) was proposed for cleansing, enrichment and sensitivity enhancement. 4'-Carboxy-substituted rosamine (CSR) was synthesized and used as derivatization reagent. An ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed for determination of cholesterol and its metabolic steroid hormones in the multiple reaction monitoring mode. RESULTS: Parameters of dual-UADLLME, MAD and UHPLC-MS/MS were all optimized. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect and extremely low limits of detection (LODs, 0.08-0.15 pg mL(-1) ) were achieved. CONCLUSIONS: Through the combination of dual-UADLLME and MAD, a determination method for cholesterol and its metabolic steroid hormones in human plasma, serum and urine samples was developed and validated with high sensitivity, selectivity, accuracy and perfect matrix effect results. Copyright © 2016 John Wiley & Sons, Ltd.
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Colesterol/análise , Cromatografia Líquida de Alta Pressão/métodos , Hormônios/análise , Microextração em Fase Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Colesterol/sangue , Colesterol/urina , Feminino , Hormônios/sangue , Hormônios/urina , Humanos , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Masculino , Micro-Ondas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Esteroides/análise , Esteroides/sangue , Esteroides/urina , UltrassomRESUMO
BACKGROUND/AIMS: Tempol is a protective antioxidant against ischemic injury in many animal models. The molecular mechanisms are not well understood. Nuclear factor erythroid 2-related factor (Nrf2) is a master transcription factor during oxidative stress, which is enhanced by activation of protein kinase C (PKC) pathway. Another factor, tubular epithelial apoptosis, is mediated by activation of phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, Akt) signaling pathway during renal ischemic injury. We tested the hypothesis that tempol activates PKC or PI3K/Akt/Nrf2 pathways to transcribe many genes that coordinate endogenous antioxidant defense. METHODS: The right renal pedicle was clamped for 45 minutes and the left kidney was removed to study renal ischemia/reperfusion (I/R) injury in C57BL/6 mice. The response was assessed from serum parameters, renal morphology and renal expression of PKC, phosphorylated-PKC (p-PKC), Nrf2, heme oxygenase-1 (HO-1), Akt, phosphorylated-Akt (p-Akt), pro-caspase-3 and cleaved caspase-3 in groups of sham and I/R mice given vehicle, or tempol (50 or 100 mg/kg, intraperitoneal injection). RESULTS: The serum malondialdehyde (MDA, marker of reactive oxygen species) doubled and the BUN and creatinine increased 5- to 10-fold after I/R injury. Tempol (50 or 100 mg/kg) prevented the increases in MDA but only tempol (50 mg/kg) lessened the increases in BUN and creatinine and moderated the acute tubular necrosis. I/R did not change expression of PKC or p-PKC but reduced renal expression of Nrf2, p-Akt, HO-1 and pro-caspase-3 and increased cleaved caspase-3. Tempol (50 mg/kg) prevented these changes produced by I/R whereas tempol (100 mg/kg) had lesser or inconsistent effects. CONCLUSION: Tempol (50 mg/kg) prevents lipid peroxidation and attenuates renal damage after I/R injury. The beneficial pathway apparently is not dependent on upregulation or phosphorylation of PKC, at lower tempol doses, does implicate upregulation of Akt with expression of Nrf2 that could account for the increase in the antioxidant gene HO-1 and a reduction in the cleavage of the cellular damage marker pro-caspase-3.
Assuntos
Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/prevenção & controle , Antioxidantes/uso terapêutico , Óxidos N-Cíclicos/uso terapêutico , Fator 2 Relacionado a NF-E2/biossíntese , Fosfatidilinositol 3-Quinase/biossíntese , Proteínas Proto-Oncogênicas c-akt/biossíntese , Animais , Antioxidantes/farmacologia , Óxidos N-Cíclicos/farmacologia , Relação Dose-Resposta a Droga , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidação de Lipídeos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Marcadores de Spin , Resultado do TratamentoAssuntos
Síndrome Coronariana Aguda/metabolismo , Plaquetas/metabolismo , Sinalização do Cálcio , Cálcio/sangue , Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/patologia , Idoso , Plaquetas/patologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/sangue , Estudos Transversais , Feminino , Humanos , Masculino , Proteínas de Neoplasias/sangue , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/sangue , Molécula 1 de Interação Estromal/sangueRESUMO
ß2-glycoprotein I (ß2-GPI) is a plasma protein that interacts with oxidized low-density lipoproteins (oxLDL) via ß2-GPI domain V to form oxLDL/ß2-GPI complexes, potential autoantigens promoting atherogenesis in patients with antiphospholipid syndrome (APS). Such a interaction would expose ß2-GPI domain I or/and IV, structures recognized by anti-ß2-GPI autoantibodies. IgG immune complexes with oxLDL/ß2-GPI complexes can interact with macrophages via Fcγ receptor, causing oxLDL/ß2-GPI endocytosis and foam cell formation, contributing to atherosclerosis. Here, we use recombinant domain V to study the interaction between oxLDL and ß2-GPI and hypothesized that domain V would interfere with this interaction thereby reducing oxLDL macrophage uptake and foam cell formation. The ß2-GPI domain V sequence was expressed by using the Pichia pastoris expression system to obtain recombinant domain V of ß2-GPI (P.rß2-GPI DV). ELISA tests demonstrated that P.rß2-GPI DV interacted with oxLDL via 7-ketocholesteryl-9-carboxynonanoate (oxLig-1), a negatively charged lipid moiety of oxLDL. The ω-carboxyl residue of oxLig-1 is required for the interaction. Serologic tests showed a significant increase in oxLDL and oxLDL/ß2-GPI levels in patients with APS (p < 0.05 compared to controls). P.rß2-GPI DV was able to bind oxLDL in high affinity and competitively inhibited native ß2-GPI (nß2-GPI) binding to free oxLDL as well as to oxLDL from the oxLDL/ß2-GPI complexes. These observations suggest that P.rß2-GPI DV may be used to inhibit the formation of the oxLDL/ß2-GPI complexes, a potential approach for reducing foam cell development and mitigating atherogenesis in patients with APS. The present work provides a new effective strategy to prevent the progression of atherothrombotic vascular complications in APS patients.
Assuntos
Complexo Antígeno-Anticorpo/metabolismo , Síndrome Antifosfolipídica/tratamento farmacológico , Autoantígenos/metabolismo , Células Espumosas/fisiologia , Lipoproteínas LDL/metabolismo , Placa Aterosclerótica/prevenção & controle , beta 2-Glicoproteína I/metabolismo , Complexo Antígeno-Anticorpo/imunologia , Síndrome Antifosfolipídica/complicações , Aterosclerose , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Autoantígenos/imunologia , Ésteres do Colesterol/metabolismo , Endocitose , Humanos , Placa Aterosclerótica/etiologia , Ligação Proteica , Estrutura Terciária de Proteína/genética , Proteínas Recombinantes/genética , beta 2-Glicoproteína I/genéticaRESUMO
BACKGROUND/AIMS: Nasopharyngeal carcinoma (NPC) is a distinctive type of head and neck cancer with the highest incidence in South China. Previous studies have proved that matrine, a main alkaloid isolated from Sophora flavescens Ait, has antitumor activity against NPC. However, the effect is not so pronounced and the underlying mechanism remains largely unclear. Here we investigated whether 14-thienyl methylene matrine (YYJ18) that was derived from matrine could exert more effective suppression activity on NPC, along with the underlying mechanism. METHODS: NPC cell lines CNE1, CNE2 and HONE1 were treated with YYJ18. Cell proliferation and apoptosis were determined by MTT assay and flow cytometry. Activation of mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathways were determined by Western blotting and quantitative RT-PCR. RESULTS: YYJ18 remarkably inhibited proliferation and induced apoptosis of all three NPC cell lines in a dose-dependent manner, especially in CNE2 cells. Furthermore, YYJ18 treatment significantly suppressed phosphorylation of p38 in CNE2 cells, but upregulated phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and Akt. Next, alterations in downstream signaling were found, including activation of BCL2-associated X protein (Bax), caspase-3 and inactivation of B-cell CLL/lymphoma 2 (Bcl-2). CONCLUSION: We demonstrate the potent inhibitory effects of 14-thienyl methylene matrine on NPC cells for the first time, which could be mediated by modulation of MAPK and PI3K/Akt pathways.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias Nasofaríngeas/tratamento farmacológico , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quinolizidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Tiofenos/farmacologia , Antineoplásicos/química , Carcinoma , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/metabolismo , Neoplasias Nasofaríngeas/patologia , Quinolizidinas/química , Relação Estrutura-Atividade , Tiofenos/química , Células Tumorais CultivadasRESUMO
Photocatalytic technology showed significant potential for addressing the issue of cyanobacterial blooms resulting from eutrophication in bodies of water. However, the traditional powder materials were easy to agglomerate and settle, which led to the decrease of photocatalytic activity. The emergence of floating photocatalyst was important for the practical application of controlling harmful algal blooms. This study was based on the efficient powder photocatalyst bismuth oxide composite copper-metal organic framework (Bi2O3 @Cu-MOF), which was successfully loaded onto melamine sponge (MS) by sodium alginate immobilization to prepare a floating photocatalyst MS/Bi2O3 @Cu-MOF for the inactivation of Microcystis aeruginosa (M. aeruginosa) under visible light. When the capacity was 0.4 g (CA0.4), MS/Bi2O3 @Cu-MOF showed good photocatalytic activity, and the inactivation rate of M. aeruginosa reached 74.462% after 120 h. MS/Bi2O3 @Cu-MOF-CA0.4 showed a large specific surface area of 30.490 m2/g and an average pore size of 22.862 nm, belonging to mesoporous materials. After 120 h of treatment, the content of soluble protein in the MS/Bi2O3 @Cu-MOF-CA0.4 treatment group decreased to 0.365 mg/L, the content of chlorophyll a (chla) was 0.023 mg/L, the content of malondialdehyde (MDA) increased to 3.168 nmol/mgprot, and the contents of various antioxidant enzymes experienced drastic changes, first increasing and then decreasing. The photocatalytic process generated·OH and·O2-, which played key role in inactivating the algae cells. Additionally, the release of Cu2+ and adsorption of the material also contributed to the process.
Assuntos
Estruturas Metalorgânicas , Microcystis , Triazinas , Cobre/metabolismo , Microcystis/metabolismo , Estruturas Metalorgânicas/metabolismo , Clorofila A , Seda/metabolismo , Pós/metabolismo , Bismuto , Proliferação Nociva de AlgasRESUMO
BACKGROUND: Lingguizhugan (LGZG) decoction, an ancient Chinese herbal remedy originating from the Eastern Han Dynasty, consists of Poria cocos, Cinnamomi ramulus, Atractylodes macrocephala, and Glycyrrhiza, as described in the Golden Chamber Synopsis. It has a history spanning over 1600 years, in which it has been primarily used for the treatment of inflammation, injuries, and fluid retention; however, the potential of LGZG decoction to ameliorate Alzheimer's disease (AD) progression by modulating the gut-brain axis through attenuation of gut microbiota and their metabolites remains unknown. PURPOSE: To examine the in vivo anti-AD effects and mechanism of LGZG decoction in alleviating AD cognitive impairment. STUDY DESIGN: Two-part experiments in vivo were designed, one for behavior tests, intestinal and brain histopathology, intestinal microbiome and quantitative determination, and another one for metabolite supplementation study. METHODS: AlCl3/D-gal was used to establish an AD-like mouse model. Behavioral tests, such as the Morris water maze test, were used to assess the effect of LGZG decoction on cognitive dysfunction. The concentration of proinflammatory mediators was measured by ELISA. The protein content was detected by western blot analysis and immunohistochemistry. The content of short-chain fatty acids was measured by LC-MS/MS. Evaluation of 16S rRNA gene sequencing for species and strain-level gut microbiome analysis was performed. RESULTS: LGZG decoction mitigated cognitive impairment in an AD-like mouse model, and decreased the deposition of amyloid-ß and the production of proinflammatory cytokines in the brain. LGZG decoction remodeled the intestinal microecology, enhanced the integrity of the intestinal and brain tissue barriers, and modulated Aß transportation through gut microbiota metabolite SCFAs. The neuroprotective effect of SCFAs on the AD-like model mice may be manifested through the inhibition of pP38 of the MAPK signaling pathway. CONCLUSION: Our results suggest that LGZG decoction reshapes the gut microbiota. SCFAs derived from the gut microbiota ameliorate the cognitive decline induced by AlCl3/D-gal through the gut-brain axis and reduce brain Aß aggregation. We propose LGZG decoction as a potential therapeutic option for AD.
RESUMO
The microbial fuel cell (MFC) is a device that simultaneously achieves electricity generation and sewage degradation. In this study, a novel cathode catalyst metal-organic frameworks (MOFs) have been fabricated by two-step hydrothermal and dual-solution method (CuCo-MOF@ZIF-8). The synthesized trimetal MOFs exhibited a 3D badminton-like structure morphology and porosity. The results of the characterizations showed that CuCo-MOF@ZIF-8 possesses greater surface area porosity and novel functional groups. The Trimetal MOF-on-MOF mode not only demonstrated the stability of the structure but also enhanced its mechanism. Molecular mechanism analysis revealed changes in the organic ligand and metal binding site due to the transformation of Cu2+ to Cu+, Co2+ to Co3+, and Zn-N to Zn-O organic connection. Furthermore, differences between the two fabrication methods were compared. The solid-state single preparation (CuCo-MOF@ZIF-8-1), was synthesized using the two-step hydrothermal method; the liquid mixed preparation material (CuCo-MOF@ZIF-8-2), was synthesized using the dual-solution method; they exhibited completely different chemical structures and morphologies during material testing and characterization. The maximum output power density of CuCo-MOF@ZIF-8-2-MFC was 246.38 mW/m2, about 2.49 times of ZIF-8 (98.72 mW/m2). The output voltage of CuCo-MOF@ZIF-8-1-MFC was measured at 357 mV over 10 d, while that of CuCo-MOF@ZIF-8-2-MFC reached 365 mV over 12 d.
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Ocean acidification (OA) driven by elevated carbon dioxide (CO2) levels is expected to disturb marine ecological processes, including the formation and control of harmful algal blooms (HABs). In this study, the effects of rising CO2 on the allelopathic effects of macroalgae Ulva pertusa to a toxic dinoflagellate Karenia mikimotoi were investigated. It was found that high level of CO2 (1000 ppmv) promoted the competitive growth of K. mikimotoi compared to the group of present ambient CO2 level (420ppmv), with the number of algal cell increased from 32.2 × 104 cells/mL to 36.75 × 104 cells/mL after 96 h mono-culture. Additionally, rising CO2 level weakened allelopathic effects of U. pertusa on K. mikimotoi, as demonstrated by the decreased inhibition rate (50.6 % under the original condition VS 34.3 % under the acidified condition after 96 h co-culture) and the decreased reactive oxygen species (ROS) level, malondialdehyde (MDA) content, antioxidant enzymes activity (superoxide dismutase (SOD), peroxidase (POD), glutathione peroxidase (GPX), glutathione reductase (GR) and catalase (CAT) and non-enzymatic antioxidants (glutathione (GSH) and ascorbic acid (ascorbate, vitamin C). Indicators for cell apoptosis of K. mikimotoi including decreased caspase-3 and -9 protease activity were observed when the co-cultured systems were under rising CO2 exposure. Furthermore, high CO2 level disturbed fatty acid synthesis in U. pertusa and significantly decreased the contents of fatty acids with allelopathy, resulting in the allelopathy weakening of U. pertusa. Collectively, rising CO2 level promoted the growth of K. mikimotoi and weakened allelopathic effects of U. pertusa on K. mikimotoi, indicating the increased difficulties in controlling K. mikimotoi using macroalgae in the future.
Assuntos
Dinoflagellida , Alga Marinha , Dióxido de Carbono/toxicidade , Concentração de Íons de Hidrogênio , Água do Mar , Dinoflagellida/fisiologia , Proliferação Nociva de AlgasRESUMO
An increasing amount of sewage has been discharged into water bodies in the progression of industrialization and urbanization, causing serious water pollution. Meanwhile, the increase of nutrients in the water induces water eutrophication and rapid growth of algae. Photocatalysis is a common technique for algal inhibition and sterilization. To improve the utilization of visible light and the conversion efficiency of solar energy, more organic photocatalytic materials have been gradually developed. In addition to ultraviolet light, partial infrared light and visible light could also be used by organic photocatalysts compared with inorganic photocatalysts. Simultaneously, organic photocatalysts also exhibit favorable stability. Most organic photocatalysts can maintain a high degradation rate for algae and bacteria after several cycles. There are various organic semiconductors, mainly including small organic molecules, such as perylene diimide (PDI), porphyrin (TCPP), and new carbon materials (fullerene (C60), graphene (GO), and carbon nanotubes (CNT)), and large organic polymers, such as graphite phase carbon nitride (g-C3N4), polypyrrole (PPy), polythiophene (PTH), polyaniline (PANI), and polyimide (PI). In this review, the classification and synthesis methods of organic photocatalytic materials were elucidated. It was demonstrated that the full visible spectral response (400-750 nm) could be stimulated by modifying organic photocatalysts. Moreover, some problems were summarized based on the research status related to algae and bacteria, and corresponding suggestions were also provided for the development of organic photocatalytic materials.
Assuntos
Nanotubos de Carbono , Polímeros , Pirróis , Luz , Esterilização , Água , CatáliseRESUMO
The sulfur-doped titanium dioxide (S-TiO2) cooperated with Zirconium based on a kind of metal-organic framework (MOF-808) was successfully prepared as cathode catalyst (S-TiO2@MOF-808) of microbial fuel cell (MFC) by two-step hydrothermal reaction. The particle size was approximately 5 µm, and the spherical S-TiO2 particle was attached to the surface of MOF-808 as irregular block solid. Zr-O, C-O and O-H bond were indicated to exist in S-TiO2@MOF-808. When n (Zr4+): n(Ti4+) was 1: 5, S-TiO2@MOF-808 showed better oxygen reduction reaction (ORR). The introduction of S-TiO2 restrained the framework collapse of MOF-808, S-TiO2@MOF-808 showed much higher catalytic stability in reaction. The recombination of sulfur and TiO2 reduced the charge transfer resistance, accelerated the electron transfer rate, and improved ORR greatly. The maximum power density of S-TiO2@MOF-808-MFC was 84.05 mW/m2, about 2.17 times of S-TiO2-MFC (38.64 mW/m2). The maximum voltage of S-TiO2@MOF-808-MFC was 205 mV, and the stability was maintained for 6 d.
Assuntos
Fontes de Energia Bioelétrica , Estruturas Metalorgânicas , Titânio , Zircônio , Eletrodos , EnxofreRESUMO
Dioxins and the emerging dioxin-like compounds (DLCs) have recruited increasing concerns about their environmental contamination, toxicity, health impacts, and mechanisms. Based on the structural similarity of dioxins and many DLCs, their toxicity was predominantly mediated by the dioxin receptor (aryl hydrocarbon receptor, AHR) in animals (including human), which can be different in expression and function among species and then possibly produce the species-specific risk or toxicity. To date, characterizing the AHR of additional species other than human and rodents can increase the accuracy of toxicity/risk evaluation and increase knowledge about AHR biology. As a key model, the medaka AHR has not been clearly characterized. Through genome survey and phylogenetic analysis, we identified four AHRs (olaAHR1a, olaAHR1b, olaAHR2a, and olaAHR2b) and two ARNTs (olaARNT1 and olaARNT2). The medaka AHR pathway was conserved in expression in nine tested tissues, of which olaAHR2a represented the predominant subform with greater abundance. Medaka AHRs and ARNTs were functional and could be efficiently transactivated by the classical dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), although olaAHR1a did not seem to cooperate with olaARNT2. In terms of function/sensitivity, the EC50 values of medaka olaAHR1a (9.01 ± 1.43 nM), olaAHR1b (4.00 ± 1.10 nM), olaAHR2a (8.75 ± 3.34 nM), and olaAHR2b (3.06 ± 0.81 nM) showed slight differences; however, they were all at the nM level. The sensitivity of four medaka AHRs to TCDD was similar to that of zebrafish dreAHR2 (the dominant form, EC50 = 3.14 ± 4.19 nM), but these medaka AHRs were more sensitive than zebrafish dreAHR1b (EC50 = 27.05 ± 18.51 nM). The additional comparison also indicated that the EC50 values in various species were usually within the nM range, but AHRs of certain subforms/species can vary by one or two orders of magnitude. In summary, the present study will enhance the understanding of AHR and help improve research on the ecotoxicity of dioxins/DLCs.
Assuntos
Dioxinas , Oryzias , Receptores de Hidrocarboneto Arílico , Poluentes Químicos da Água , Peixe-Zebra , Animais , Receptores de Hidrocarboneto Arílico/metabolismo , Receptores de Hidrocarboneto Arílico/genética , Dioxinas/toxicidade , Poluentes Químicos da Água/toxicidade , Filogenia , Especificidade da EspécieRESUMO
α1,6-Fucosyltransferase (Fut8) knock-out (Fut8(-/-)) mice showed an abnormality in pre-B cell generation. Membrane assembly of pre-BCR is a crucial checkpoint for pre-B cell differentiation and proliferation in both humans and mice. The assembly of pre-BCR on the cell surface was substantially blocked in the Fut8-knockdown pre-B cell line, 70Z/3-KD cells, and then completely restored by re-introduction of the Fut8 gene to 70Z/3-KD (70Z/3-KD-re) cells. Moreover, loss of α1,6-fucosylation (also called core fucosylation) of µHC was associated with the suppression of the interaction between µHC and λ5. In contrast to Fut8(+/+) CD19(+)CD43(-) cells, the subpopulation expressing the µHC·λ5 complex in the Fut8(-/-) CD19(+)CD43(-) cell fraction was decreased. The pre-BCR-mediated tyrosine phosphorylation of CD79a and activation of Btk were attenuated in Fut8-KD cells, and restored in 70Z/3-KD-re cells. The frequency of CD19(low)CD43(-) cells (pre-B cell enriched fraction) was also reduced in Fut8(-/-) bone marrow cells, and then the levels of IgM, IgG, and IgA of 12-week-old Fut8(-/-) mice sera were significantly lower than those of Fut8(+/+) mice. Our results suggest that the core fucosylation of µHC mediates the assembly of pre-BCR to regulate pre-BCR intracellular signaling and pre-B cell proliferation.
Assuntos
Fucose/metabolismo , Fucosiltransferases/metabolismo , Cadeias mu de Imunoglobulina/metabolismo , Células Precursoras de Linfócitos B/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais/fisiologia , Animais , Fucose/genética , Fucose/imunologia , Fucosiltransferases/genética , Fucosiltransferases/imunologia , Glicosilação , Imunoglobulina A/genética , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Imunoglobulina G/genética , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Imunoglobulina M/genética , Imunoglobulina M/imunologia , Imunoglobulina M/metabolismo , Cadeias lambda de Imunoglobulina/genética , Cadeias lambda de Imunoglobulina/imunologia , Cadeias lambda de Imunoglobulina/metabolismo , Cadeias mu de Imunoglobulina/genética , Cadeias mu de Imunoglobulina/imunologia , Camundongos , Camundongos Knockout , Células Precursoras de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologiaRESUMO
Hydrogen produced by electrolyzing water has attracted extensive attention as an effective way to generate and store new energy by using renewable energy. Electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were the core reactions in the process of hydrogen production by water electrolysis, however, due to the low efficiency of the electrolytic device caused by its slow kinetic reaction and the dependence on noble metal catalysts (platinum and iridium/ruthenium (oxide)), which limited its wide application. The preparation of high-efficiency catalysts with high catalytic activity, stability, low cost and scalability played a vital role in promoting the development of hydrogen production technology from electrolytic water and has become a current research hotspot. Metal alloy catalysts have been widely studied as high-efficiency electrocatalysts. This study introduced and analyzed the mechanism and application of metal alloy catalyst in hydrogen and oxygen evolution reaction, summarized and discussed the progress in the design, preparation and application of metal alloy electrocatalysts. Finally, the strategy and prospect of new high-efficiency electrocatalysts were proposed.
Assuntos
Ligas , Hidrogênio , Catálise , Oxigênio , ÁguaRESUMO
The leaf chlorophyll content (LCC) of vegetation is closely related to photosynthetic efficiency and biological activity. Jujube (Ziziphus jujuba Mill.) is a traditional economic forest tree species. Non-destructive monitoring of LCC of jujube is of great significance for guiding agroforestry production and promoting ecological environment protection in arid and semi-arid lands. Hyperspectral data is an important data source for LCC detection. However, hyperspectral data consists of a multitude of bands and contains extensive information. As a result, certain bands may exhibit high correlation, leading to redundant spectral information. This redundancy can distort LCC prediction results and reduce accuracy. Therefore, it is crucial to select appropriate preprocessing methods and employ effective data mining techniques when analyzing hyperspectral data. This study aims to evaluate the performance of hyperspectral data for estimating LCC of jujube trees by integrating different derivative processing techniques with different dimensionality reduction algorithms. Hyperspectral reflectance data were obtained through simulations using an invertible forest reflectance model (INFORM) and measurements from jujube tree canopies. The least absolute shrinkage and selection operator (LASSO) and elastic net (EN) were employed to identify the important bands in the original spectra (OS), first derivative spectra (FD), and second derivative spectra (SD). Support vector regression (SVR) was used to establish the estimation model. The results show that compared with full-spectrum modeling, LASSO and EN algorithms are effective methods for preventing overfitting in LCC machine learning estimation models for different spectral derivatives. The LASSO/EN-based estimation models constructed using FD and SD exhibited superior R2 compared to the OS. The important band of SD can best reveal the relevant information of jujube LCC, and SD-EN-SVR is the most ideal model in both the simulated dataset (R2 = 0.99, RMSE=0.61) and measured dataset (R2 = 0.89, RMSE=0.91). Our results provided a reference for rapid and non-destructive estimation of the LCC of agroforestry vegetation using canopy hyperspectral data.