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Human land-use results in widespread range change across taxa. Anthropogenic pressures can result in species' realized niches expanding, shifting, or contracting. Marginalization occurs when contraction constrains species to the geographic or ecological extremes of their historic niche. Using 4,785 terrestrial mammal species, we show that range contraction results in niche space and habitat diversity loss. Additionally, ecological marginalization is a common consequence of range contraction caused by human land use change. Remnant populations become located in the climatic and topographic extremes of their historic niche that are more likely to be at the periphery of their historic niche at greater distances from historic niche centroids. This ecological marginalization is associated with poor performance and increased extinction risk independent of geographic range loss. Range loss and marginalization may create a "double whammy" in vulnerable groups, such as large-bodied species and species with small geographical range size. Our results reveal a hitherto unrecognized conservation threat that is vital to incorporate into conservation assessment and management.
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Ecossistema , Mamíferos , Animais , Humanos , Geografia , Extinção BiológicaRESUMO
A key approach in developing green chemistry involves converting solar energy into chemical energy of biomolecules through photocatalysis. Photocatalysis can facilitate the regeneration of nicotinamide cofactors during redox processes. Nicotinamide cofactor biomimetics (NCBs) are economical substitutes for natural cofactors. Here, photocatalytic regeneration of NADH and reduced NCBs (NCBsred) using graphitic carbon nitride (g-C3N4) was developed. The process involves g-C3N4 as the photocatalyst, Cp*Rh(bpy)H2O2+ as the electron mediator, and Triethanolamine as the electron donor, facilitating the reduction of NAD+ and various oxidative NCBs (NCBsox) under light irradiation. Notably, the highest reduction yield of 48.32 % was achieved with BANA+, outperforming the natural cofactor NAD+. Electrochemical analysis reveals that the reduction efficiency and capacity of cofactors relies on their redox potentials. Additionally, a coupled photo-enzymatic catalysis system was explored for the reduction of 4-Ketoisophorone by Old Yellow Enzyme XenA. Among all the NCBsox and NAD+, the highest conversion ratio of over 99 % was obtained with BANA+. After recycled for 8 times, g-C3N4 maintained over 93.6 % catalytic efficiency. The photocatalytic cofactor regeneration showcases its outstanding performance with NAD+ as well as NCBsox. This work significantly advances the development of photocatalytic cofactor regeneration for artificial cofactors and its potential application.
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Biocatálise , Oxirredução , Processos Fotoquímicos , Materiais Biomiméticos/química , Materiais Biomiméticos/metabolismo , Estrutura Molecular , NAD/química , NAD/metabolismo , Biomimética , Niacinamida/química , Niacinamida/metabolismo , Compostos de Nitrogênio/química , GrafiteRESUMO
Low-intensity ultrasound, as a form of biological enhancement technology, holds significant importance in the field of biological nitrogen removal. This study utilized low-intensity ultrasound (200 W, 6 min) to enhance partial nitrification and investigated its impact on sludge structure, as well as the internal relationship between structure and properties. The results demonstrated that ultrasound induced a higher concentration of nitrite in the effluent (40.16 > 24.48 mg/L), accompanied by a 67.76% increase in the activity of ammonia monooxygenase (AMO) and a 41.12% increase in the activity of hydroxylamine oxidoreductase (HAO), benefiting the partial nitrification. Based on the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theoretical analysis, ultrasonic treatment enhanced the electrostatic interaction energy (WR) between sludge flocs, raising the total interaction energy from 46.26 kT to 185.54 kT, thereby causing sludge dispersion. This structural alteration was primarily attributed to the fact that the tightly bonded extracellular polymer (TB-EPS) after ultrasound was found to increase hydrophilicity and negative charge, weakening the adsorption between sludge cells. In summary, this study elucidated that the change in sludge structure caused by ultrasonic treatment has the potential to enhance the nitrogen removal performance by partial nitrification.
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Phytoremediation has emerged as a common technique for remediating Cd pollution in farmland soil. Moreover, phosphorus, an essential element for plants, can alter the pectin content of plant cell walls and facilitate the accumulation of Cd in plant tissues, thereby enhancing phytoremediation efficiency. Therefore, pot experiments were conducted in order to investigate the effect of phosphorus levels on Cd extraction, phosphorus transformation and phosphorus-related genes during phytoremediation. The results revealed that an optimal application of suitable phosphate fertilizers elevated the soil's pH and electrical conductivity (EC), facilitated the conversion of soil from insoluble phosphorus into available forms, augmented the release of pertinent enzyme activity, and induced the expression of phosphorus cycling-related genes. These enhancements in soil conditions significantly promoted the growth of ryegrass. When applying phosphorus at a rate of 600 mg/kg, ryegrass exhibited plant height, dry weight, and chlorophyll relative content that were 1.27, 1.26, and 1.18 times higher than those in the control group (P0), while the Cd content was 1.12 times greater than that of P0. The potentially toxic elements decline ratio and bioconcentration factor were 42.86% and 1.17 times higher than those of P0, respectively. Consequently, ryegrass demonstrated the highest Cd removal efficiency under these conditions. Results from redundancy analysis (RDA) revealed a significant correlation among pH, total phosphorus, heavy metal content, phosphorus forms, soil enzyme activity, and phosphorus-related genes. In conclusion, this study suggests applying an optimal amount of suitable phosphate fertilizers can enhance restoration efficiency, leading to a reduction in soil Cd content and ultimately improving the safety of crop production in farmlands.
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Biodegradação Ambiental , Cádmio , Lolium , Fósforo , Poluentes do Solo , Poluentes do Solo/metabolismo , Poluentes do Solo/análise , Cádmio/metabolismo , Fósforo/metabolismo , Fósforo/análise , Lolium/metabolismo , Lolium/genética , Lolium/crescimento & desenvolvimento , Fertilizantes/análise , Solo/químicaRESUMO
Following ion-adsorption rare earth mining, the residual tailings experience considerable heavy metal contamination and gradually evolve into a pollution source. Therefore, the leaching characteristics and environmental impact of heavy metals in ion-adsorption rare earth tailings require immediate and thorough investigation. This study adopted batch and column experiments to investigate the leaching behaviour of heavy metals in tailings and assess the impact of tailings on paddy soil, thereby providing a scientific basis for environmental protection in mining areas. The results showed that Mn, Zn, and Pb contents were 431.67, 155.05, and 264.33â¯mg·kg-1, respectively, which were several times higher than their respective background values, thereby indicating significant heavy metal contamination in the tailings. The batch leaching experiment indicated that Mn and Pb were priority control heavy metals. Heavy metals were divided into fast and slow leaching stages. The Mn and Pb leaching concentrations far exceeded environmental limits. The DoseResp model perfectly fitted the leaching of all heavy metals from the tailings (R2 > 0.99). In conjunction with the findings of the column experiment and correlation analysis, the chemical form, rainfall pH, ammonia nitrogen, and mineral properties were identified as the primary factors controlling heavy metal release from tailings. Rainfall primarily caused heavy metal migration in the acid-extraction form from the tailings. The tailing leachate not only introduced heavy metals into the paddy soil but also caused the transformation of the chemical form of heavy metals in the paddy soil, further exacerbating the environmental risk posed by heavy metals. The study findings are significant for environmental conservation in mining areas and implementing environmentally friendly practices in rare earth mining.
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Monitoramento Ambiental , Metais Pesados , Metais Terras Raras , Mineração , Chuva , Poluentes do Solo , Metais Pesados/análise , Poluentes do Solo/análise , Metais Terras Raras/análise , Chuva/química , Solo/química , AdsorçãoRESUMO
Hydrogen sulfide (H2S) promotes microangiogenesis and revascularization after ischemia. Neovascularization starts with the destruction of intercellular junctions and is accompanied by various endothelial cell angiogenic behaviors. Follistatin-like 1 (FSTL1) is a cardiovascular-protective myokine that works against ischemic injury. The present study examined whether FSTL1 was involved in H2S-induced angiogenesis and explored the underlying molecular mechanism. We observed that H2S accelerated blood perfusion after ischemia in the mouse hindlimb ischemia model. Western blot analysis showed that H2S stabilized FSTL1 transcript and increased FSTL1 and Human antigen R (HuR) levels in skeletal muscle. RNA-interference HuR significantly inhibited the H2S-promoted increase in FSTL1 levels. Exogenous FSTL1 promoted the wound-healing migration of human umbilical vein endothelial cells (HUVECs) and increased monolayer endothelial barrier permeability. Immunostaining showed that FSTL1 increased interendothelial gap formation and decreased VE-Cadherin, Occludin, Connexin-43, and Claudin-5 expression. In addition, FSTL1 significantly increased the phosphorylation of Src and VEGFR2. However, the Src inhibitor, not the VEGFR2 inhibitor, could block FSTL1-induced effects in angiogenesis. In conclusion, we demonstrated that H2S could upregulate the expression of FSTL1 by increasing the HuR levels in skeletal muscle, and paracrine FSTL1 could initiate angiogenesis by opening intercellular junctions via the Src signaling pathway.NEW & NOTEWORTHY The myocyte-derived paracrine protein FSTL1 acts on vascular endothelial cells and initiates the process of angiogenesis by opening the intercellular junction via activating Src kinase. H2S can significantly upregulate FSTL1 protein levels in skeletal muscles by increasing HuR expression.
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The utilization of unnatural nicotinamide cofactors for reactions catalyzed by oxidoreductases has gained increasing interest. Totally synthetic nicotinamide cofactor biomimetics (NCBs) are cost-effective and convenient to synthesize. Thus, it has become increasingly important to develop enzymes that accept NCBs. Here, we have engineered SsGDH to favor a newly synthesized unnatural cofactor 3-carbamoyl-1-(4-carboxybenzyl) pyridin-1-ium (BANA+ ). Using inâ situ ligand minimization tool, sites 44 and 114 were identified as hotspots for mutagenesis. All the double mutants demonstrated 2.7-7.7-fold improvements in catalytic activity, and the best double mutant E44D/E114â L exhibited 10.6-fold increased catalytic efficiency toward BANA+ . These results provide valuable information for the rational engineering of oxidoreductases with versatile NCBs-dependency, as well as the design of novel biomimetic cofactors.
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Biomimética , Glucose 1-Desidrogenase , Glucose 1-Desidrogenase/genética , Oxirredutases/genética , Niacinamida , CatáliseRESUMO
The presence and diversity of endophytic fungi associated with host plants are important not just for host plant growth and defense, but also impact the production of medicinal secondary metabolites. However, the correlation between endophytic fungi and crocin production in Crocus sativus (CS) remains underexplored. Here, we explore the relationship between endophytic fungal diversity and crocin content among different CS tissues and field sites. Specifically, we isolated endophytic fungi from five different field sites (Shanghai, Jiande, Huzhou, Anhui, and Hebei) and five different tissues (corm, scape, leaf, petal, and stigma) and analyzed fungal community diversity, richness, and evenness. We identified a total of 32 endophytic fungal taxa, assigned to 7 orders within 4 classes (Eurotiomycetes, Agaricomycetes, Dothideomycetes, and Sordariomycetes). The most dominant order was Eurotiales, and the most dominant genera were Penicillium and Talaromyces. Species richness tended to be highest in belowgrown tissues, such as corm and scape. Additionally, several fungal taxa were found to be either site- or tissue-specific. Three genera in particular were correlated with crocin content: Penicillium, Sistotrema, and Bjerkandera. Given the fact that endophytic microorganisms can both promote the production of secondary metabolites in host plants and potentially produce secondary metabolites themselves, further study is required to understand the mechanistic relationship between these and other fungal genera and crocin production.
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Ascomicetos , Crocus , Penicillium , Fungos , Endófitos , China , Penicillium/genéticaRESUMO
With the recent increases in energy demands, the dust hazards of coal mining caused by transportation, loading and unloading and other processes are becoming increasingly serious. To control dust in open pit coal mines more environmentally friendly and efficiently, and to promote the use and development of non-in situ high-yield urease microorganisms for dust suppression in coal mines, Bacillus pasteurii was selected for dust suppression experiments in this article. Additionally, the growth of microorganisms in the coal dust microenvironment was simulated, and the effect of microbial mineralization products on the calorific value of upper coal dust was further studied. Our findings indicated that Bacillus pasteurii induced dust suppression by forming a calcite precipitate with non-uniform particle size to coal dust cementation. Moreover, after a single spray, the wind erosion resistance efficiency was 84% when the wind speed was set at 10 m/s. The growth of microorganisms and urease activity in the coal dust leachate were largely equal to those in the control group, reaching a peak at approximately 24 h, that the maximum growth quantity of OD600 was about 1.5, and the maximum urease activity was 11 mmol·L-1·min-1. The difference between the peak heat release rate of mixed coal dust and pure coal was only 4.82 kW/m2, which would not affect the value of coal products. Non in-situ Bacillus pasteurii can be growth metabolized normally in the microenvironment of coal dust. Finally, the mechanism of coal dust suppression by mineralization of microbial bacterial solution to form calcium carbonate was described by a reaction equation, which is important for further application and development of microbial dust suppressants.
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Minas de Carvão , Sporosarcina , Poeira/análise , Urease , Carbonato de Cálcio , Minerais , Carvão Mineral/análiseRESUMO
The present study aimed to investigate the protective effect of S-propargyl-cysteine (SPRC) on atherosclerosis progression in mice. A mouse model of vulnerable atherosclerotic plaque was created in ApoE-/- mice by carotid artery tandem stenosis (TS) combined with a Western diet. Macrophotography, lipid profiles, and inflammatory markers were measured to evaluate the antiatherosclerotic effects of SPRC compared to atorvastatin as a control. Histopathological analysis was performed to assess the plaque stability. To explore the protective mechanism of SPRC, human umbilical vein endothelial cells (HUVECs) were cultured in vitro and challenged with oxidized low-density lipoprotein (ox-LDL). Cell viability was determined with a Cell Counting Kit-8 (CCK-8). Endothelial nitric oxide synthase (eNOS) phosphorylation and mRNA expression were detected by Western blot and RT-qPCR respectively. The results showed that the lesion area quantified by en face photographs of the aortic arch and carotid artery was significantly less, plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were reduced, plaque collagen content was increased and matrix metalloproteinase-9 (MMP-9) was decreased in 80 mg/kg per day SPRC-treated mice compared with model mice. These findings support the role of SPRC in plaque stabilization. In vitro studies revealed that 100 µmol/L SPRC increased the cell viability and the phosphorylation level of eNOS after ox-LDL challenge. These results suggest that SPRC delays the progression of atherosclerosis and enhances plaque stability. The protective effect may be at least partially related to the increased phosphorylation of eNOS in endothelial cells.
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Aterosclerose , Placa Aterosclerótica , Animais , Humanos , Camundongos , Colesterol/metabolismo , Cisteína/farmacologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Lipoproteínas LDL/farmacologia , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Fosforilação , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patologiaRESUMO
Granular activated carbon (GAC) filtration can be employed to synchronously quench residual H2O2 from the upstream UV/H2O2 process and further degrade dissolved organic matter (DOM). In this study, rapid small-scale column tests (RSSCTs) were performed to clarify the mechanisms underlying the interactions between H2O2 and DOM during the GAC-based H2O2 quenching process. It was observed that GAC can catalytically decompose H2O2, with a long-lasting high efficiency (>80% for approximately 50,000 empty-bed volumes). DOM inhibited GAC-based H2O2 quenching via a pore-blocking effect, especially at high concentrations (10 mg/L), with the adsorbed DOM molecules being oxidized by the continuously generated ·OH; this further deteriorated the H2O2 quenching efficiency. In batch experiments, H2O2 could enhance DOM adsorption by GAC; however, in RSSCTs, it deteriorated DOM removal. This observation could be attributed to the different ·OH exposure in these two systems. It was also observed that aging with H2O2 and DOM altered the morphology, specific surface area, pore volume, and the surface functional groups of GAC, owing to the oxidation effect of H2O2 and ·OH on the GAC surface as well as the effect of DOM. Additionally, the changes in the content of persistent free radicals in the GAC samples were insignificant following different aging processes. This work contributes to enhancing understanding regarding the UV/H2O2-GAC filtration scheme, and promoting the application in drinking water treatment.
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Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal , Matéria Orgânica Dissolvida , Peróxido de Hidrogênio , AdsorçãoRESUMO
PURPOSE: To investigate the prognostic value of quantitative analysis of CT among patients with idiopathic pulmonary fibrosis (IPF) by quantifying the fibrosis extent and to attempt to provide precise medium-long term prognostic predictions for individual patients. METHODS: This was a retrospective cohort study that included 95 IPF patients in Zhongshan Hospital, Fudan University. 64 patients firstly diagnosed with IPF from 2009 to 2015 was included as the derivation cohort. Information regarding sex, age, the Gender-Age-Physiology (GAP) index, high-resolution computed tomography (HRCT) images, survival status, and pulmonary function parameters including forced vital capacity (FVC), FVC percent predicted (FVC%pred), diffusing capacity of carbon monoxide (DLCO), DLCO percent predicted (DLCO%pred), carbon monoxide transfer coefficient (KCO), KCO percent predicted (KCO%pred) were collected. 31 patients were included in the validation cohort. The Synapse 3D software was used to quantify the fibrotic lung volume (FLV) and total lung volume (TLV). The ratio of FLV to TLV was calculated and labeled CTFLV/TLV%, reflecting the extent of fibrosis. All the physiological variants and CTFLV/TLV% were analyzed for the dimension of survival through both univariate analysis and multivariate analysis. Formulas for predicting the probability of death based on the baseline CTFLV/TLV% were calculated by logistic regression, and validated by the validation cohort. RESULTS: The univariate analysis indicated that CTFLV/TLV% along with DLCO%pred, KCO%pred and GAP index were significantly correlated with survival. However, only CTFLV/TLV% was meaningful in the multivariate analysis for prognostic prediction (HR 1.114, 95% CI 1.047-1.184, P = 0.0006), and the best cutoff was 11%, based on receiver operating characteristic (ROC) curve analysis. The survival times for the CTFLV/TLV% ≤ 11% and CTFLV/TLV% > 11% groups were significantly different. Given the CTFLV/TLV% data, the death probability of a patient at 1 year, 3 years and 5 years could be calculated by using a particular formula. The formulas were tested by the validation cohort, showed high sensitivity (88.2%), specificity (92.8%) and accuracy (90.3%). CONCLUSION: Quantitative volume analysis of CT might be useful for evaluating the extent of fibrosis in the lung. The CTFLV/TLV% could be a valuable biomarker for precisely predicting the medium-long term prognosis of individual patients with IPF.
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Monóxido de Carbono , Fibrose Pulmonar Idiopática , Humanos , Estudos Retrospectivos , Fibrose Pulmonar Idiopática/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Capacidade Vital , Prognóstico , FibroseRESUMO
BACKGROUND: Agmatine is a member of biogenic amines and is an important medicine which is widely used to regulate body balance and neuroprotective effects. At present, the industrial production of agmatine mainly depends on the chemical method, but it is often accompanied by problems including cumbersome processes, harsh reaction conditions, toxic substances production and heavy environmental pollution. Therefore, to tackle the above issues, arginine decarboxylase was overexpressed heterologously and rationally designed in Corynebacterium crenatum to produce agmatine from glucose by one-step fermentation. RESULTS: In this study, we report the development in the Generally Regarded as Safe (GRAS) L-arginine-overproducing C. crenatum for high-titer agmatine biosynthesis through overexpressing arginine decarboxylase based on metabolic engineering. Then, arginine decarboxylase was mutated to release feedback inhibition and improve catalytic activity. Subsequently, the specific enzyme activity and half-inhibitory concentration of I534D mutant were increased 35.7% and 48.1%, respectively. The agmatine production of the whole-cell bioconversion with AGM3 was increased by 19.3% than the AGM2. Finally, 45.26 g/L agmatine with the yield of 0.31 g/g glucose was achieved by one-step fermentation of the engineered C. crenatum with overexpression of speAI534D. CONCLUSIONS: The engineered C. crenatum strain AGM3 in this work was proved as an efficient microbial cell factory for the industrial fermentative production of agmatine. Based on the insights from this work, further producing other valuable biochemicals derived from L-arginine by Corynebacterium crenatum is feasible.
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Agmatina/metabolismo , Carboxiliases/metabolismo , Corynebacterium/genética , Corynebacterium/metabolismo , Engenharia Metabólica , Arginina/biossíntese , Carboxiliases/química , Carboxiliases/genética , Fermentação , Glucose/metabolismo , Microbiologia Industrial , Proteínas Recombinantes/metabolismoRESUMO
[Figure: see text].
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Lesões das Artérias Carótidas/enzimologia , Estenose das Carótidas/enzimologia , Movimento Celular , Proliferação de Células , Histona-Lisina N-Metiltransferase/metabolismo , Músculo Liso Vascular/enzimologia , Miócitos de Músculo Liso/enzimologia , Neointima , Animais , Artérias Carótidas/enzimologia , Artérias Carótidas/patologia , Lesões das Artérias Carótidas/genética , Lesões das Artérias Carótidas/patologia , Estenose das Carótidas/genética , Estenose das Carótidas/patologia , Células Cultivadas , Modelos Animais de Doenças , Histona-Lisina N-Metiltransferase/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia , Ratos , Transdução de Sinais , Remodelação VascularRESUMO
Skin wound healing tends to slow down with aging, which is detrimental to both minor wound recovery in daily life and the recovery after surgery. The aim of current study was to explore the effect of histone deacetylase 6 (HDAC6) on wound healing during aging. Cultured human dermal fibroblasts (HDFs) and mouse full-thickness skin wound model were used to explore the functional changes of replicative senescent dermal fibroblasts and the effect of aging on skin wound healing. Scratch wound healing assay revealed significantly decreased migration speed of senescent HDFs, and BrdU incorporation assay indicated their considerably retardant proliferation. The protein expression levels of collagen and HDAC6 were significantly decreased in both senescent HDFs and skin tissues from aged mice. HDAC6 activity inhibition with highly selective inhibitor tubastatin A (TsA) or HDAC6 knockdown with siRNA decreased the migration speed of HDFs and considerably suppressed fibroblast differentiation induced by transforming growth factor-ß1 (TGF-ß1), which suggests the involvement of HDAC6 in regulating fundamental physiological activities of dermal fibroblasts. In vivo full-thickness skin wound healing was significantly delayed in young HDAC6 knockout mice when compared with young wild type mice. In addition, the wound healing was significantly slower in aged wild type mice than that in young wild type mice, and became even worse in aged HDAC6 knockout aged mice. Compared to the aged wild type mice, aged HDAC6 knockout mice exhibited delayed angiogenesis, reduced collagen synthesis, and decreased collagen deposition in skin wounds. Together, these results suggest that delayed skin wound healing in aged mice is associated with impaired fibroblast function. Adequate expression and activity of HDAC6 are required for fibroblasts migration and differentiation.
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Pele , Cicatrização , Humanos , Animais , Camundongos , Idoso , Desacetilase 6 de Histona , Movimento Celular , Colágeno/metabolismo , Colágeno/farmacologia , Fibroblastos , Camundongos Knockout , Células CultivadasRESUMO
Hydrogen sulfide, a small molecule, produced by endogenous enzymes, such as CTH, CBS, and MPST using L-cysteine as substrates, has been reported to have numerous protective effects. However, the key problem that the target of H2S and how it can affect the structure and activity of biological molecules is still unknown. Till now, there are two main theories of its working mechanism. One is that H2S can modify the free thiol in cysteine to produce the persulfide state of the thiol and the sulfhydration of cysteine can significantly change the structure and activity of target proteins. The other theory is that H2S, as an antioxidant molecule, can directly break the disulfide bond in target proteins, and the persulfide state of thiol can be an intermediate product during the reaction. Both phenomena exit for no doubt since they are both supported by large amounts of experiments. Here, we will summarize both theories and try to discuss which one is the more effective or direct mechanism for H2S and what is the relationship between them. Therefore, we will discover more protein targets of H2S with the mechanism and understand more about the effect of this small molecule.
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Sulfeto de Hidrogênio , Cisteína , Proteínas/genética , Compostos de SulfidrilaRESUMO
Quasi-collimated beam apparatus (QCBA), a typical bench scale UV apparatus, is crucial for the biodosimetry determination of UV dose in target reactors. However, the key parameters for the QCBA construction are usually estimated via rule-of-thumb calculations. Computational fluid dynamics models are applied in this study to simulate the UV fluence rate (FR) distributions in QCBAs. QCBAs with either a cylindrical tube or successive apertures irradiate quasi parallel light into selected dishes. The simulated Petri factors (PF) in the target QCBAs with a single aperture were all >0.84, and increased with the extended distance (L1) from the UV lamp to the upper aperture. QCBAs with two successive apertures are recommended compared with those with three apertures or cylindrical tube. A trend of FR distribution from dispersed to concentrated is observed when L1 or the interval distance between each aperture increases in a dual-aperture QCBA. QCBAs with multiple lamps were favorable to increase the UV output power, while having a nearly negligible loss of parallelism. An actual QCBA was constructed, and the maximal and average FR and PF values in a 60-mm dish were 0.159 and 0.164 W/m2, and 0.967, respectively, in accordance with the simulated results.
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Hidrodinâmica , Purificação da Água , Desinfecção , Raios UltravioletaRESUMO
Endogenous hydrogen sulfide (H2S) affects cholesterol homeostasis and liver X receptor α (LXRα) expression. However, whether low-density lipoprotein (LDL) receptor (LDLR), a key player in cholesterol homeostasis, is regulated by exogenous H2S through LXRα signaling has not been determined. We investigated the effects of sodium hydrosulfide (NaHS, H2S donor) on LDLR expression in the presence or absence of LXR agonists, T0901317 or GW3965 in HepG2 cells. We found that H2S strongly accumulated LDLR precursor in the presence of T0901317. Hence, LDLR transcription and the genes involved in LDLR precursor maturation and degradation were studied. T0901317 increased the LDLR mRNA level, whereas H2S did not affect LDLR transcription. H2S had no significant effect on the expression of LXRα and inducible degrader of LDLR (IDOL). H2S and T0901317 altered mRNA levels of several enzymes for N- and O-glycosylation and endoplasmic reticulum (ER) chaperones assisting LDLR maturation, but did not affect their protein levels. H2S decreased proprotein convertase subtilisin/kexin type 9 (PCSK9) protein levels and its mRNA level elevated by T0901317. T0901317 with PCSK9 siRNA also accumulated LDLR precursor as did T0901317 with H2S. High glucose increased PCSK9 protein levels and attenuated LDLR precursor accumulation induced by T0901317 with H2S. Taken together, H2S accumulates LDLR precursor by downregulating PCSK9 expression but not through the LXRα-IDOL pathway, LDLR transcriptional activation, or dysfunction of glycosylation enzymes and ER chaperones. These results also indicate that PCSK9 plays an important role in LDLR maturation in addition to its well-known effect on the degradation of LDLR mature form.
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Sulfeto de Hidrogênio/metabolismo , Receptores X do Fígado/metabolismo , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Benzoatos/farmacologia , Benzilaminas/farmacologia , Linhagem Celular Tumoral , Colesterol/metabolismo , Retículo Endoplasmático/fisiologia , Glicosilação/efeitos dos fármacos , Células Hep G2 , Homeostase/fisiologia , Humanos , Hidrocarbonetos Fluorados/farmacologia , Receptores X do Fígado/agonistas , Pró-Proteína Convertase 9/genética , Interferência de RNA , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Sulfetos/farmacologia , Sulfonamidas/farmacologia , Transcrição Gênica/efeitos dos fármacos , Ativação Transcricional/genéticaRESUMO
Diabetes (especially Type II) is one of the primary threats to cardiovascular health. Wound healing defects and vascular dysfunction are common in diabetic patients, and the primary cause of deterioration is sustained high plasma glucose. microRNA, a noncoding RNA, has regulatory functions that are critical to maintaining homeostasis. MicroRNA (miR)-126-3p is a potential diabetes biomarker and a proangiogenic factor, and its plasma level decreases in diabetic patients. Previous studies have revealed the proangiogenic character of the gasotransmitter hydrogen sulfide (H2S). However, little is known about the relationship between H2S and miR-126-3p when the extracellular glucose level is high, let alone their influences on deteriorated endothelial cell migration, a key component of angiogenesis, which is crucial for wound healing. Human umbilical vein endothelial cells (HUVECs) were treated with high glucose (33.3 mmol/L) or normal glucose (5.5 mmol/L) for 48 h. Affymetrix miRNA profiling and real-time PCR were used to validate the miRNA expression. An H2S probe (HSip-1) was used to detect endogenous H2S. Scratch wound-healing assays were used to evaluate HUVEC migration. The protein levels were quantified by Western blot. Both exogenous and endogenous H2S could upregulate the miR-126-3p levels in HUVECs or muscle tissue. High glucose decreased the H2S level and the protein expression of the H2S-producing enzyme cystathionine γ-lyase (CSE) in HUVECs; however, the DNA methyltransferase 1 (DNMT1) protein level was upregulated. CSE overexpression not only increased the miR-126-3p level by decreasing the DNMT1 protein level but also rescued the deteriorated cell migration in HUVECs treated with high glucose. DNMT1 overexpression decreased the miR-126-3p level and inhibited the migration of HUVECs, whereas silencing DNMT1 improved cell migration. High glucose decreased the endogenous H2S and miR-126-3p levels and increased the DNMT1 expression, thus inducing the migration dysfunction of HUVECs. Treatment with exogenous H2S or the overexpression of the endogenously produced enzyme CSE would rescue this migration dysfunction through H2S-DNMT1-miR-126-3p.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Sulfeto de Hidrogênio/farmacologia , MicroRNAs/genética , Neovascularização Fisiológica/efeitos dos fármacos , Animais , Vasos Sanguíneos/efeitos dos fármacos , Vasos Sanguíneos/crescimento & desenvolvimento , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/patologia , Movimento Celular/efeitos dos fármacos , Cistationina gama-Liase/genética , DNA (Citosina-5-)-Metiltransferase 1/genética , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Glucose/toxicidade , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Sulfeto de Hidrogênio/metabolismo , Camundongos , Neovascularização Fisiológica/genética , Transdução de Sinais/efeitos dos fármacos , Cicatrização/efeitos dos fármacosRESUMO
Leonurine (LEO) is a bioactive small molecular compound that has protective effects on the cardiovascular system and prevents the early progression of atherosclerosis; however, it is not clear whether LEO is effective for plaque stability. A novel mouse atherosclerosis model involving tandem stenosis (TS) of the right carotid artery combined with western diet (WD) feeding was used. Apolipoprotein E gene-deficient mice were fed with a WD and received LEO administration daily for 13 weeks. TS was introduced 6 weeks after the onset of experiments. We found that LEO enhanced plaque stability by increasing fibrous cap thickness and collagen content while decreasing the population of CD68-positive cells. Enhanced plaque stability by LEO was associated with the nitric oxide synthase (NOS)-nitric oxide (NO) system. LEO restored the balance between endothelial NOS(E)- and inducible NOS(iNOS)-derived NO production; suppressed the NF-κB signaling pathway; reduced the level of the inflammatory infiltration in plaque, including cytokine interleukin 6; and downregulated the expression of adhesion molecules. These findings support the distinct role of LEO in plaque stabilization. In vitro studies with oxidized low-density lipoprotein-challenged human umbilical vein endothelial cells revealed that LEO balanced NO production and inhibited NF-κB/P65 nuclear translocation, thus mitigating inflammation. In conclusion, the restored balance of the NOS-NO system and mitigated inflammation contribute to the plaque-stabilizing effect of LEO. SIGNIFICANCE STATEMENT: LEO restored the balance between endothelial NOS and inducible NOS in NO production and inhibited excessive inflammation in atherosclerotic "unstable" and rupture-prone plaques in apolipoprotein E gene-deficient mice. The protective effect of LEO for stabilizing atherosclerotic plaques was due to improved collagen content, increased fibrous cap thickness, and decreased accumulation of macrophages/foam cells. So far, LEO has passed the safety and feasibility test of phase I clinical trial.