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1.
Cell ; 164(1-2): 219-232, 2016 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-26771493

RESUMO

Although a number of repair strategies have been shown to promote axon outgrowth following neuronal injury in the mammalian CNS, it remains unclear whether regenerated axons establish functional synapses and support behavior. Here, in both juvenile and adult mice, we show that either PTEN and SOCS3 co-deletion, or co-overexpression of osteopontin (OPN)/insulin-like growth factor 1 (IGF1)/ciliary neurotrophic factor (CNTF), induces regrowth of retinal axons and formation of functional synapses in the superior colliculus (SC) but not significant recovery of visual function. Further analyses suggest that regenerated axons fail to conduct action potentials from the eye to the SC due to lack of myelination. Consistent with this idea, administration of voltage-gated potassium channel blockers restores conduction and results in increased visual acuity. Thus, enhancing both regeneration and conduction effectively improves function after retinal axon injury.


Assuntos
Axônios/fisiologia , Colículos Superiores/fisiologia , 4-Aminopiridina/farmacologia , Animais , Axônios/efeitos dos fármacos , Fator Neurotrófico Ciliar/metabolismo , Fenômenos Eletrofisiológicos , Olho/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Camundongos , Bainha de Mielina/metabolismo , Nervo Óptico , Osteopontina/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Bloqueadores dos Canais de Potássio/farmacologia , Regeneração/efeitos dos fármacos , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Sinapses
2.
J Neuroinflammation ; 21(1): 148, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38840180

RESUMO

BACKGROUND: White matter injury (WMI) represents a significant etiological factor contributing to neurological impairment subsequent to Traumatic Brain Injury (TBI). CD36 receptors are recognized as pivotal participants in the pathogenesis of neurological disorders, including stroke and spinal cord injury. Furthermore, dynamic fluctuations in the phenotypic polarization of microglial cells have been intimately associated with the regenerative processes within the injured tissue following TBI. Nevertheless, there is a paucity of research addressing the impact of CD36 receptors on WMI and microglial polarization. This investigation aims to elucidate the functional role and mechanistic underpinnings of CD36 in modulating microglial polarization and WMI following TBI. METHODS: TBI models were induced in murine subjects via controlled cortical impact (CCI). The spatiotemporal patterns of CD36 expression were examined through quantitative polymerase chain reaction (qPCR), Western blot analysis, and immunofluorescence staining. The extent of white matter injury was assessed via transmission electron microscopy, Luxol Fast Blue (LFB) staining, and immunofluorescence staining. Transcriptome sequencing was employed to dissect the molecular mechanisms underlying CD36 down-regulation and its influence on white matter damage. Microglial polarization status was ascertained using qPCR, Western blot analysis, and immunofluorescence staining. In vitro, a Transwell co-culture system was employed to investigate the impact of CD36-dependent microglial polarization on oligodendrocytes subjected to oxygen-glucose deprivation (OGD). RESULTS: Western blot and qPCR analyses revealed that CD36 expression reached its zenith at 7 days post-TBI and remained sustained at this level thereafter. Immunofluorescence staining exhibited robust CD36 expression in astrocytes and microglia following TBI. Genetic deletion of CD36 ameliorated TBI-induced white matter injury, as evidenced by a reduced SMI-32/MBP ratio and G-ratio. Transcriptome sequencing unveiled differentially expressed genes enriched in processes linked to microglial activation, regulation of neuroinflammation, and the TNF signaling pathway. Additionally, bioinformatics analysis pinpointed the Traf5-p38 axis as a critical signaling pathway. In vivo and in vitro experiments indicated that inhibition of the CD36-Traf5-MAPK axis curtailed microglial polarization toward the pro-inflammatory phenotype. In a Transwell co-culture system, BV2 cells treated with LPS + IFN-γ exacerbated the damage of post-OGD oligodendrocytes, which could be rectified through CD36 knockdown in BV2 cells. CONCLUSIONS: This study illuminates that the suppression of CD36 mitigates WMI by constraining microglial polarization towards the pro-inflammatory phenotype through the down-regulation of the Traf5-MAPK signaling pathway. Our findings present a potential therapeutic strategy for averting neuroinflammatory responses and ensuing WMI damage resulting from TBI.


Assuntos
Antígenos CD36 , Camundongos Endogâmicos C57BL , Microglia , Animais , Microglia/metabolismo , Microglia/patologia , Camundongos , Antígenos CD36/metabolismo , Antígenos CD36/genética , Camundongos Knockout , Substância Branca/patologia , Substância Branca/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Polaridade Celular/fisiologia , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/patologia , Transdução de Sinais/fisiologia
3.
FASEB J ; 37(9): e23112, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37534961

RESUMO

Traumatic brain injury (TBI), particularly diffuse axonal injury (DAI), often results in sympathetic hyperactivity, which can exacerbate the prognosis of TBI patients. A key component of this process is the role of neutrophils in causing neuroinflammation after TBI by forming neutrophil extracellular traps (NETs), but the connection between NETs and sympathetic excitation following TBI remains unclear. Utilizing a DAI rat model, the current investigation examined the role of NETs and the HMGB1/JNK/AP1 signaling pathway in this process. The findings revealed that sympathetic excitability intensifies and peaks 3 days post-injury, a pattern mirrored by the activation of microglia, and the escalated NETs and HMGB1 levels. Subsequent in vitro exploration validated that HMGB1 fosters microglial activation via the JNK/AP1 pathway. Moreover, in vivo experimentation revealed that the application of anti-HMGB1 and AP1 inhibitors can mitigate microglial M1 polarization post-DAI, effectively curtailing sympathetic hyperactivity. Therefore, this research elucidates that post-TBI, NETs within the PVN may precipitate sympathetic hyperactivity by stimulating M1 microglial polarization through the HMGB1/JNK/AP1 pathway.


Assuntos
Lesões Encefálicas Traumáticas , Armadilhas Extracelulares , Ratos , Animais , Camundongos , Microglia/metabolismo , Armadilhas Extracelulares/metabolismo , Lesões Encefálicas Traumáticas/metabolismo , Fenótipo , Camundongos Endogâmicos C57BL
4.
Environ Sci Technol ; 58(11): 4989-5002, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38442002

RESUMO

Global warming and acidification, induced by a substantial increase in anthropogenic CO2 emissions, are expected to have profound impacts on biogeochemical cycles. However, underlying mechanisms of nitrous oxide (N2O) production in estuarine and coastal sediments remain rarely constrained under warming and acidification. Here, the responses of sediment N2O production pathways to warming and acidification were examined using a series of anoxic incubation experiments. Denitrification and N2O production were largely stimulated by the warming, while N2O production decreased under the acidification as well as the denitrification rate and electron transfer efficiency. Compared to warming alone, the combination of warming and acidification decreased N2O production by 26 ± 4%, which was mainly attributed to the decline of the N2O yield by fungal denitrification. Fungal denitrification was mainly responsible for N2O production under the warming condition, while bacterial denitrification predominated N2O production under the acidification condition. The reduced site preference of N2O under acidification reflects that the dominant pathways of N2O production were likely shifted from fungal to bacterial denitrification. In addition, acidification decreased the diversity and abundance of nirS-type denitrifiers, which were the keystone taxa mediating the low N2O production. Collectively, acidification can decrease sediment N2O yield through shifting the responsible production pathways, partly counteracting the warming-induced increase in N2O emissions, further reducing the positive climate warming feedback loop.


Assuntos
Bactérias , Desnitrificação , Bactérias/metabolismo , Aquecimento Global , Óxido Nitroso/análise , Concentração de Íons de Hidrogênio , Solo
5.
Environ Sci Technol ; 58(21): 9261-9271, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38739716

RESUMO

Methane, a greenhouse gas, plays a pivotal role in the global carbon cycle, influencing the Earth's climate. Only a limited number of microorganisms control the flux of biologically produced methane in nature, including methane-oxidizing bacteria, anaerobic methanotrophic archaea, and methanogenic archaea. Although previous studies have revealed the spatial and temporal distribution characteristics of methane-metabolizing microorganisms in local regions by using the marker genes pmoA or mcrA, their biogeographical patterns and environmental drivers remain largely unknown at a global scale. Here, we used 3419 metagenomes generated from georeferenced soil samples to examine the global patterns of methane metabolism marker gene abundances in soil, which generally represent the global distribution of methane-metabolizing microorganisms. The resulting maps revealed notable latitudinal trends in the abundances of methane-metabolizing microorganisms across global soils, with higher abundances in the sub-Arctic, sub-Antarctic, and tropical rainforest regions than in temperate regions. The variations in global abundances of methane-metabolizing microorganisms were primarily governed by vegetation cover. Our high-resolution global maps of methane-metabolizing microorganisms will provide valuable information for the prediction of biogenic methane emissions under current and future climate scenarios.


Assuntos
Metano , Microbiologia do Solo , Solo , Metano/metabolismo , Solo/química , Archaea/genética , Archaea/metabolismo , Bactérias/metabolismo , Bactérias/genética , Metagenoma
6.
Environ Sci Technol ; 58(2): 1152-1163, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38166438

RESUMO

Coastal wetlands are hotspots for methane (CH4) production, reducing their potential for global warming mitigation. Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays a crucial role in bridging carbon and nitrogen cycles, contributing significantly to CH4 consumption. However, the role of n-DAMO in reducing CH4 emissions in coastal wetlands is poorly understood. Here, the ecological functions of the n-DAMO process in different saltmarsh vegetation habitats as well as bare mudflats were quantified, and the underlying microbial mechanisms were explored. Results showed that n-DAMO rates were significantly higher in vegetated habitats (Scirpus mariqueter and Spartina alterniflora) than those in bare mudflats (P < 0.05), leading to an enhanced contribution to CH4 consumption. Compared with other habitats, the contribution of n-DAMO to the total anaerobic CH4 oxidation was significantly lower in the Phragmites australis wetland (15.0%), where the anaerobic CH4 oxidation was primarily driven by ferric iron (Fe3+). Genetic and statistical analyses suggested that the different roles of n-DAMO in various saltmarsh wetlands may be related to divergent n-DAMO microbial communities as well as environmental parameters such as sediment pH and total organic carbon. This study provides an important scientific basis for a more accurate estimation of the role of coastal wetlands in mitigating climate change.


Assuntos
Nitratos , Áreas Alagadas , Metano , Anaerobiose , Poaceae , Oxirredução , Carbono , Nitritos
7.
Appl Environ Microbiol ; 89(6): e0010223, 2023 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-37191511

RESUMO

Natural microbial communities produce a diverse array of secondary metabolites with ecologically and biotechnologically relevant activities. Some of them have been used clinically as drugs, and their production pathways have been identified in a few culturable microorganisms. However, since the vast majority of microorganisms in nature have not been cultured, identifying the synthetic pathways of these metabolites and tracking their hosts remain a challenge. The microbial biosynthetic potential of mangrove swamps remains largely unknown. Here, we examined the diversity and novelty of biosynthetic gene clusters in dominant microbial populations in mangrove wetlands by mining 809 newly reconstructed draft genomes and probing the activities and products of these clusters by using metatranscriptomic and metabolomic techniques. A total of 3,740 biosynthetic gene clusters were identified from these genomes, including 1,065 polyketide and nonribosomal peptide gene clusters, 86% of which showed no similarity to known clusters in the Minimum Information about a Biosynthetic Gene Cluster (MIBiG) repository. Of these gene clusters, 59% were harbored by new species or lineages of Desulfobacterota-related phyla and Chloroflexota, whose members are highly abundant in mangrove wetlands and for which few synthetic natural products have been reported. Metatranscriptomics revealed that most of the identified gene clusters were active in field and microcosm samples. Untargeted metabolomics was also used to identify metabolites from the sediment enrichments, and 98% of the mass spectra generated were unrecognizable, further supporting the novelty of these biosynthetic gene clusters. Our study taps into a corner of the microbial metabolite reservoir in mangrove swamps, providing clues for the discovery of new compounds with valuable activities. IMPORTANCE At present, the majority of known clinical drugs originated from cultivated species of a few bacterial lineages. It is vital for the development of new pharmaceuticals to explore the biosynthetic potential of naturally uncultivable microorganisms using new techniques. Based on the large numbers of genomes reconstructed from mangrove wetlands, we identified abundant and diverse biosynthetic gene clusters in previously unsuspected phylogenetic groups. These gene clusters exhibited a variety of organizational architectures, especially for nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS), implying the presence of new compounds with valuable activities in the mangrove swamp microbiome.


Assuntos
Bactérias , Metagenoma , Áreas Alagadas , Família Multigênica , Vias Biossintéticas , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Metabolômica , China , Biodiversidade
8.
Glob Chang Biol ; 29(13): 3821-3832, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37021604

RESUMO

Dark carbon fixation (DCF), through which chemoautotrophs convert inorganic carbon to organic carbon, is recognized as a vital process of global carbon biogeochemical cycle. However, little is known about the response of DCF processes in estuarine and coastal waters to global warming. Using radiocarbon labelling method, the effects of temperature on the activity of chemoautotrophs were investigated in benthic water of the Yangtze estuarine and coastal areas. A dome-shaped thermal response pattern was observed for DCF rates (i.e., reduced rates at lower or higher temperatures), with the optimum temperature (Topt ) varying from about 21.9 to 32.0°C. Offshore sites showed lower Topt values and were more vulnerable to global warming compared with nearshore sites. Based on temperature seasonality of the study area, it was estimated that warming would accelerate DCF rate in winter and spring but inhibit DCF activity in summer and fall. However, at an annual scale, warming showed an overall promoting effect on DCF rates. Metagenomic analysis revealed that the dominant chemoautotrophic carbon fixation pathways in the nearshore area were Calvin-Benson-Bassham (CBB) cycle, while the offshore sites were co-dominated by CBB and 3-hydroxypropionate/4-hydroxybutyrate cycles, which may explain the differential temperature response of DCF along the estuarine and coastal gradients. Our findings highlight the importance of incorporating DCF thermal response into biogeochemical models to accurately estimate the carbon sink potential of estuarine and coastal ecosystems in the context of global warming.


Assuntos
Ecossistema , Aquecimento Global , Ciclo do Carbono , Estações do Ano , Carbono/metabolismo
9.
Microb Ecol ; 85(2): 383-399, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35298685

RESUMO

Bacteria play an important role in regulating carbon (C), nitrogen (N), and sulfur (S) in estuarine intertidal wetlands. To gain insights into the ecological and metabolic modes possessed by bacteria in estuarine intertidal wetlands, a total of 78 surface soil samples were collected from China's coastal intertidal wetlands to examine the spatial and seasonal variations of bacterial taxonomic composition, assembly processes, and ecological system functions through shotgun metagenomic and 16S rRNA gene sequencing. Obvious spatiotemporal dynamic patterns in the bacterial community structure were identified, with more pronounced seasonal rather than spatial variations. Dispersion limitation was observed to act as a critical factor affecting community assembly, explaining approximately half of the total variation in the bacterial community. Functional bacterial community structure exhibited a more significant latitudinal change than seasonal variability, highlighting that functional stability of the bacterial communities differed with their taxonomic variability. Identification of biogeochemically related links between C, N, and S cycles in the soils showed the adaptive routed metabolism of the bacterial communities and the strong interactions between coupled metabolic pathways. Our study broadens the insights into the taxonomic and functional profiles of bacteria in China's estuarine intertidal soils and helps us understand the effects exerted by environmental factors on the ecological health and microbial diversity of estuarine intertidal flats.


Assuntos
Ecossistema , Solo , RNA Ribossômico 16S/genética , Áreas Alagadas , Bactérias , China
10.
Environ Sci Technol ; 57(6): 2660-2671, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36734984

RESUMO

Estuarine and coastal environments are assumed to contribute to nitrous oxide (N2O) emissions under increasing nitrogen loading. However, isotopic and molecular mechanisms underlying N2O production pathways under elevated nitrogen concentration remain poorly understood. Here we used microbial inhibition, isotope mass balance, and molecular approaches to investigate N2O production mechanisms in estuarine and coastal sediments through a series of anoxic incubations. Site preference of the N2O molecule increased due to increasing nitrate concentration, suggesting the changes in N2O production pathways. Enhanced N2O production under high nitrate concentration was not mediated by bacterial denitrification, but instead was mainly regulated by fungal denitrification. Elevated nitrate concentration increased the contribution of fungal denitrification to N2O production by 11-25%, whereas it decreased bacterial N2O production by 16-33%. Chemodenitrification was also enhanced by high nitrate concentration, contributing to 13-28% of N2O production. Elevated nitrate concentration significantly mediated nirK-type denitrifiers structure and abundance, which are the keystone taxa driving N2O production. Collectively, these results suggest that increasing nitrate concentration can shift N2O production pathways from bacterial to fungal and chemodenitrification, which are mainly responsible for the enhanced N2O production and have widespread implications for N2O projections under ongoing nitrogen pollution in estuarine and coastal ecosystems.


Assuntos
Nitrogênio , Óxido Nitroso , Nitrogênio/metabolismo , Desnitrificação , Nitratos/química , Ecossistema
11.
Am J Nephrol ; 53(8-9): 591-602, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36349764

RESUMO

INTRODUCTION: This study aimed to examine the trends in adherence to the Physical Activity Guidelines (PAG) for aerobic activity and sedentary time and their effects on mortality and disease progression among US adults with chronic kidney disease (CKD). METHODS: We studied individuals from the National Health and Nutrition Examination Survey 2007-08 to 2017-18 with a mortality file in 2015. Multivariate regression models were used to evaluate the association between adherence to PAG and sedentary time with mortality, estimated glomerular filtration rate (eGFR), and urine albumin-to-creatinine ratio. RESULTS: For the CKD population, adherence rate increased from 48.2% in 2007-08 to 55.0% in 2017-18, and sedentary time peaked in 2013-14 (7.5 h/day) and then decreased afterward. There was no difference in the trends across the non-CKD and CKD population. For the CKD population, adherence to the PAG was significantly associated with all-cause mortality (HR, 0.49; 95% CI: 0.38-0.63), malignant neoplasm mortality (HR, 0.30; 95% CI: 0.17-0.52), and albumin-creatinine ratio (OR, -0.27; 95% CI: -0.39 to -0.15). Sedentary time was significantly associated with all-cause mortality (HR, 1.12; 95% CI: 1.08-1.15), heart disease mortality (HR, 1.13; 95% CI: 1.08-1.19), and eGFR (OR, -0.49; 95% CI: -0.72 to -0.26). CONCLUSIONS: Favorable trends were observed in adherence to the PAG and sedentary time. Adherence to the PAG and reduction in sedentary time reduced all-cause and cause-specific mortality and prevented disease progression differently. Efforts are needed to decrease sedentary time rather than adhering to the PAG for aerobic activity alone.


Assuntos
Insuficiência Renal Crônica , Adulto , Humanos , Creatinina , Inquéritos Nutricionais , Insuficiência Renal Crônica/complicações , Taxa de Filtração Glomerular , Exercício Físico , Progressão da Doença , Albuminas , Fatores de Risco
12.
Environ Sci Technol ; 56(9): 5939-5949, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35465670

RESUMO

Acidification of estuarine and coastal waters is anticipated to influence nitrogen (N) removal processes, which are critical pathways for eliminating excess N from these ecosystems. We found that denitrification rates decreased significantly under acidified conditions (P < 0.05), which reduced by 41-53% in estuarine and coastal sediments under an approximately 0.3 pH reduction of the overlying water. However, the N removal rates through the anaerobic ammonium oxidation (anammox) process were concomitantly promoted under the same acidification conditions (increased by 47-109%, P < 0.05), whereas the total rates of N loss were significantly inhibited by aquatic acidification (P < 0.05), as denitrification remained the dominant N removal pathway. More importantly, the emission of nitrous oxide (N2O) from estuarine and coastal sediments was greatly stimulated by aquatic acidification (P < 0.05). Molecular analyses further demonstrated that aquatic acidification also altered the functional microbial communities in estuarine and coastal sediments; and the abundance of denitrifiers was significantly reduced (P < 0.05), while the abundance of anammox bacteria remained relatively stable. Collectively, this study reveals the effects of acidification on N removal processes and the underlying mechanisms and suggests that the intensifying acidification in estuarine and coastal waters might reduce the N removal function of these ecosystems, exacerbate eutrophication, and accelerate global climate change.


Assuntos
Microbiota , Nitrogênio , Desnitrificação , Estuários , Concentração de Íons de Hidrogênio , Nitrogênio/análise
13.
Environ Sci Technol ; 56(23): 17430-17442, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36347244

RESUMO

Nitrous oxide (N2O) emissions from lakes exhibit significant spatiotemporal heterogeneity, and quantitative identification of the different N2O production processes is greatly limited, causing the role of nitrification to be undervalued or ignored in models of a lake's N2O emissions. Here, the contributions of nitrification and denitrification to N2O production were quantitatively assessed in the eutrophic Lake Taihu using molecular biology and isotope mapping techniques. The N2O fluxes ranged from -41.48 to 28.84 µmol m-2 d-1 in the lake, with lower N2O concentrations being observed in spring and summer and significantly higher N2O emissions being observed in autumn and winter. The 15N site preference and relevant isotopic evidence demonstrated that denitrification contributed approximately 90% of the lake's gross N2O production during summer and autumn, 27-83% of which was simultaneously eliminated via N2O reduction. Surprisingly, nitrification seemed to act as a key process promoting N2O production and contributing to the lake as a source of N2O emissions. A combination of N2O isotopocule-based approaches and molecular techniques can be used to determine the precise characteristics of microbial N2O production and consumption in eutrophic lakes. The results of this study provide a basis for accurately assessing N2O emissions from lakes at the regional and global scales.


Assuntos
Lagos , Nitrificação , Desnitrificação , Óxido Nitroso
14.
Environ Sci Technol ; 56(20): 14828-14839, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36194569

RESUMO

Global estuarine ecosystems are experiencing severe nitrogen pollution and ocean acidification (OA) simultaneously. Sedimentary denitrification is an important way of reactive nitrogen removal but at the same time leads to the emission of large amounts of nitrous oxide (N2O), a potent greenhouse gas. It is known that OA in estuarine regions could impact denitrification and N2O production; however, the underlying mechanism is still underexplored. Here, sediment incubation and pure culture experiments were conducted to explore the OA impacts on microbial denitrification and the associated N2O emissions in estuarine sediments. Under neutral (in situ) conditions, fungal N2O emission dominated in the sediment, while the bacterial and fungal sources had a similar role under acidification. This indicated that acidification decreased the sedimentary fungal denitrification and likely inhibited the activity of fungal denitrifiers. To explore molecular mechanisms, a denitrifying fungal strain of Penicillium janthinellum was isolated from the sediments. By using deuterium-labeled single-cell Raman spectroscopy and isobaric tags for relative and absolute quantitation proteomics, we found that acidification inhibited electron transfers in P. janthinellum and downregulated expressions of the proteins related to energy production and conservation. Two collaborative pathways of energy generation in the P. janthinellum were further revealed, that is, aerobic oxidative phosphorylation and TCA cycle and anoxic pyruvate fermentation. This indicated a distinct energy supply strategy from bacterial denitrification. Our study provides insights into fungi-mediated nitrogen cycle in acidifying aquatic ecosystems.


Assuntos
Desnitrificação , Gases de Efeito Estufa , Bactérias/metabolismo , Deutério/metabolismo , Ecossistema , Gases de Efeito Estufa/metabolismo , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Óxido Nitroso/análise , Oceanos e Mares , Piruvatos/metabolismo , Água do Mar
15.
Environ Res ; 205: 112432, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34843720

RESUMO

Studying nitrous oxide (N2O) production and consumption processes along an intertidal elevation gradient can improve the understanding of N2O dynamics among coastal wetlands. A natural-abundance isotope technique was applied to characterize the processes responsible for N2O emission in high, middle and low intertidal zones in the Yangtze Estuary. The results showed that N2O emission rates in high tidal zones (0.84 ± 0.35 nmol g-1 h-1) were significantly higher than those in middle (0.21 ± 0.04 nmol g-1 h-1) and low tidal zones (0.26 ± 0.05 nmol g-1 h-1). Gross N2O production and consumption rates were greater in high and low tidal zones than in middle tidal zones, whereas N2O consumption proportions generally increased from high to low tidal zones. N2O consumption was quite pronounced, implying that N2O emission in estuarine wetlands accounts for only a small fraction of the total production. Higher degrees of N2O consumption were the pivotal driver of less N2O emission in low tidal zones. Bacterial denitrification (>84%) was the dominant pathway, although hydroxylamine (NH2OH) oxidation/fungal denitrification contributed substantially to N2O production in high tidal flats. The contribution to N2O production exhibited a decrease in NH2OH oxidation/fungal denitrification and an increase in bacterial denitrification with decreasing elevation. Changes in N2O dynamics along the elevation gradient were affected by carbon and nitrogen substrate availabilities as well as the redox environments. Overall, our findings highlight the importance of N2O consumption in controlling N2O emission in intertidal wetlands, especially with higher inundation frequencies and durations.


Assuntos
Estuários , Óxido Nitroso , Nitrogênio , Áreas Alagadas
16.
Environ Res ; 215(Pt 2): 114280, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36103926

RESUMO

As the important benthic animal in coastal wetlands, crab bioturbation may significantly affect the nitrogen (N) budgets by regulating microbial N transformation processes. However, the response of interaction between different microbial N processes to crab bioturbation remains poorly understood. Here, a 30-day microcosmic experiment was conducted using sediment collected from the Yangtze Estuary wetland, followed by the determination of temporal variations of physicochemical parameters, N removal (denitrification plus anammox, which is defined as N2 production) and retention rates (nitrate dissimilatory reduction to ammonium, DNRA) as well as relevant gene abundances in response to different crabs densities. The results showed that crab bioturbation simultaneously promoted the rates of N2 production and DNRA processes. These two process rates were positively associated with the intensity of crab bioturbation, which was supported by molecular analysis of relevant functional gene abundance. Crab bioturbation was more beneficial to DNRA than N2 production. Due to this disproportionate stimulation, crab bioturbation increased the importance of DNRA, indicating that N retention was becoming more significant under crab bioturbation in estuarine and coastal wetlands. The variations of sediment total organic carbon and oxygen availability driven by crab bioturbation were the critical factors mediating the changes in microbial N removal and retention. Overall, our findings highlighted that crab bioturbation can affect the N budgets in estuarine and coastal wetlands by altering the competition between microbial N removal and retention.


Assuntos
Compostos de Amônio , Braquiúros , Animais , Carbono , Desnitrificação , Nitratos/análise , Nitrogênio/análise , Oxigênio , Áreas Alagadas
17.
Br J Neurosurg ; 36(6): 693-698, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35393907

RESUMO

BACKGROUND: Mechanical obstruction is the most common cause of shunt failure for hydrocephalic patients. However, the diagnosis is extremely challenging and often requires invasive testing methods. Thus, a simple and non-invasive technique is in urgent need to predict the intracranial pressure (ICP) of hydrocephalic patients during their post-surgical follow-up, which could help neurosurgeons to determine the conditions of the shunt system. MATERIALS AND METHODS: Two groups of patients were enrolled in the current study. In group I, patients were enrolled as they were diagnosed with high ICP hydrocephalus and received shunt surgery. The shunt valve pressures were taken for their post-surgical ICP. Meanwhile, the participants of group II exhibited abnormally increased lumbar puncture opening pressure (LPOP; from 180 to 400 mmH2O). Both the ICP and LPOP were used to match with their corresponding tympanic membrane temperature (TMT). RESULTS: When patients' ICP were in the normal range (group I, from 50 to 180 mmH2O), the TMT correlated with ICP in a linear regression model (R2 = 0.59, p < 0.001). Interestingly, when patients exhibited above-normal ICP (LPOP was from 180 to 400 mmH2O), their TMT fit well with the ICP in a third-order polynomial regression (R2 = 0.88). When the ICP was 287.98 mmH2O, the TMT approached the vertex, which was 38.54 °C. Based on this TMT-ICP algorithm, we invented a non-invasive ICP monitor system. Interestingly, a tight linear correlation was detected between the ICP data drawn from the non-invasive device and Codman ICP monitoring system (R2 = 0.93, p < 0.01). CONCLUSIONS: We believe the TMT-ICP algorithm (the Y-Jiang model) could be used for preliminary prediction of shunt malfunction as well as monitoring ICP changes.


Assuntos
Hidrocefalia , Pressão Intracraniana , Humanos , Invenções , Hidrocefalia/diagnóstico , Hidrocefalia/cirurgia , Monitorização Fisiológica , Derivações do Líquido Cefalorraquidiano
18.
J Cell Physiol ; 236(1): 235-248, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32519365

RESUMO

The median survival time of lower grade glioma (LGG) tumors spans a wide range of 2-10 years and is highly dependent on the molecular characteristics and tumor location. Currently, there is no prognostic predictor for these tumors based on autophagy-related (ATG) genes. A prognostic risk score model based on the most significant seven ATG genes was established for LGG. These seven genes, including GRID2, FOXO1, MYC, PTK6, IKBKE, BIRC5, and TP73, have been screened as potentially therapeutic targets. The Kaplan-Meier survival curve analyses validated that patients with high or low risk scores had significantly different overall survival. Following the multivariate Cox regression and area under the ROC curve (AUC) analysis, a final prognostic model based on age, World Health Organization grade, 1p19q-codeletion status, and ATG risk score was performed as an independent prognostic indicator (training set: p = 4.09E-05, AUC = 0.901; validation set-1: p = .00069, AUC = 0.808; validation set-2: p = .0376, AUC = 0.830). Subsequently, a prognostic nomogram was constructed for individualized survival prediction. The calibration plots showed excellent predict efficiency between probability and actual overall survival. In this study, we provided several potential biomarkers for further developing potentially therapeutic targets of LGG. We also established a prognostic model and nomogram to improve the clinical glioma management and assist individualized survival prediction.


Assuntos
Autofagia/fisiologia , Neoplasias Encefálicas/patologia , Glioma/patologia , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/metabolismo , Feminino , Glioma/metabolismo , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Nomogramas , Prognóstico , Fatores de Risco
19.
Cell Mol Neurobiol ; 41(8): 1651-1663, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32770297

RESUMO

Concussion is a widely recognized environmental risk factor for neurodegenerative diseases, including Parkinson's disease (PD). Small-vessel disease of the brain has been reported to contribute to neurodegenerative diseases. In this study, we observed BBB disruption in wild-type (WT) mice, but not in matrix metalloproteinase 9 (MMP-9) knockout mice, subjected to single severe traumatic brain injury (ssTBI). Furthermore, treating ssTBI mice with the MMP-9 inhibitor GM6001 effectively maintained BBB integrity, promoted the elimination of damaged mitochondria via mitophagy, and then prevented neuronal death and progressive neurodegeneration. However, we did not observe this neuroprotective effect of MMP-9 inhibition in beclin-1-/+ mice. Collectively, these findings revealed that concussion led to BBB disruption via MMP-9, and that GM6001 prevented the development of PD via the autophagy pathway.


Assuntos
Autofagia/efeitos dos fármacos , Lesões Encefálicas Traumáticas/tratamento farmacológico , Dipeptídeos/uso terapêutico , Metaloproteinase 9 da Matriz/metabolismo , Inibidores de Metaloproteinases de Matriz/uso terapêutico , Transtornos Parkinsonianos/tratamento farmacológico , Animais , Autofagia/fisiologia , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Encéfalo/patologia , Lesões Encefálicas Traumáticas/enzimologia , Lesões Encefálicas Traumáticas/patologia , Dipeptídeos/farmacologia , Feminino , Masculino , Inibidores de Metaloproteinases de Matriz/farmacologia , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transtornos Parkinsonianos/enzimologia , Transtornos Parkinsonianos/patologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Índices de Gravidade do Trauma
20.
J Environ Sci (China) ; 104: 376-386, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33985740

RESUMO

Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems. However, the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes (DNRPs) and the fate of reactive nitrogen remain poorly understood. In this study, the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas. The results showed that marine aquaculture significantly increased the denitrification (DNF) and dissimilatory nitrate reduction to ammonium (DNRA) rates and decreased the rate of anaerobic ammonium oxidation (ANA), as compared with non-aquaculture sites. DNF was the dominant pathway contributing to the total nitrate reduction, and its contribution to the total nitrate reduction significantly increased from 66.72% at non-aquaculture sites to 78.50% at aquaculture sites. Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes, leading to variations in the nitrate reduction rates. Although nitrate removal rates increased in the marine aquaculture area, ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times, respectively, higher than those at non-aquaculture sites. Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area, and the retained reactive nitrogen could diffuse with the tidal current to the entire bay, thereby aggravating N pollution in the entire study area. These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays. This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.


Assuntos
Compostos de Amônio , Nitratos , Compostos de Amônio/análise , Aquicultura , Baías , China , Desnitrificação , Ecossistema , Nitratos/análise , Nitrogênio/análise , Oxirredução
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