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1.
PLoS Biol ; 18(6): e3000741, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32520929

RESUMO

Mitochondrial metabolic remodeling is a hallmark of the Trypanosoma brucei digenetic life cycle because the insect stage utilizes a cost-effective oxidative phosphorylation (OxPhos) to generate ATP, while bloodstream cells switch to aerobic glycolysis. Due to difficulties in acquiring enough parasites from the tsetse fly vector, the dynamics of the parasite's metabolic rewiring in the vector have remained obscure. Here, we took advantage of in vitro-induced differentiation to follow changes at the RNA, protein, and metabolite levels. This multi-omics and cell-based profiling showed an immediate redirection of electron flow from the cytochrome-mediated pathway to an alternative oxidase (AOX), an increase in proline consumption, elevated activity of complex II, and certain tricarboxylic acid (TCA) cycle enzymes, which led to mitochondrial membrane hyperpolarization and increased reactive oxygen species (ROS) levels. Interestingly, these ROS molecules appear to act as signaling molecules driving developmental progression because ectopic expression of catalase, a ROS scavenger, halted the in vitro-induced differentiation. Our results provide insights into the mechanisms of the parasite's mitochondrial rewiring and reinforce the emerging concept that mitochondria act as signaling organelles through release of ROS to drive cellular differentiation.


Assuntos
Metabolômica , Mitocôndrias/metabolismo , Trypanosoma brucei brucei/crescimento & desenvolvimento , Trypanosoma brucei brucei/metabolismo , Trifosfato de Adenosina/biossíntese , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Respiração Celular/efeitos dos fármacos , Transporte de Elétrons/efeitos dos fármacos , Elétrons , Glucose/farmacologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Redes e Vias Metabólicas/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Oxirredução , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Prolina/metabolismo , Proteoma/metabolismo , Proteínas de Protozoários/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Transcriptoma/genética , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/genética
2.
PLoS One ; 15(5): e0232360, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379772

RESUMO

The free radical nitric oxide (NO) is a powerful metabolic regulator in vertebrates and invertebrates. At cellular concentrations in the nanomolar range, and simultaneously reduced internal oxygen partial pressures (pO2), NO completely inhibits cytochrome-c-oxidase (CytOx) activity and hence mitochondrial- and whole-tissue respiration. The infaunal clam Arctica islandica regulates pO2 of hemolymph and mantle cavity water to mean values of <5 kPa, even in a completely oxygen-saturated environment of 21 kPa. These low internal pO2 values support a longer NO lifespan and NO accumulation in the body fluids and can thus trigger a depression of metabolic rate in the clams. Measurable amounts of NO formation were detected in hemocyte cells (~110 pmol NO 100-1 hemocytes h-1 at 6 kPa), which was not prevented in the presence of the NO synthase inhibitor L-NAME, and in the gill filaments of A. islandica. Adding a NO donor to intact gills and tissue homogenate significantly inhibited gill respiration and CytOx activity below 10 kPa. Meanwhile, the addition of the NO-oxidation product nitrite did not affect metabolic rates. The high nitrite levels found in the hemolymph of experimental mussels under anoxia do not indicate cellular NO production, but could be an indication of nitrate reduction by facultative anaerobic bacteria associated with tissue and/or hemolymph biofilms. Our results suggest that NO plays an important role in the initiation of metabolic depression during self-induced burrowing and shell closure of A. islandica. Furthermore, NO appears to reduce mitochondrial oxygen radical formation during surfacing and cellular reoxygenation after prolonged periods of hypoxia and anoxia.


Assuntos
Bivalves/metabolismo , Hipóxia/metabolismo , Óxido Nítrico/metabolismo , Animais , Antioxidantes/metabolismo , Bivalves/fisiologia , Respiração Celular , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Radicais Livres/metabolismo , Brânquias/metabolismo , Glutationa/metabolismo , Hemócitos/metabolismo , Hemolinfa/metabolismo , Longevidade/fisiologia , Mitocôndrias/metabolismo , Nitritos/metabolismo , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo
4.
PLoS One ; 15(4): e0231173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32251487

RESUMO

Acetaminophen is one of the most common over-the-counter pain medications used worldwide and is considered safe at therapeutic dose. However, intentional and unintentional overdose accounts for up to 70% of acute liver failure cases in the western world. Extensive research has demonstrated that the induction of oxidative stress and mitochondrial dysfunction are central to the development of acetaminophen-induced liver injury. Despite the insight gained on the mechanism of acetaminophen toxicity, there still is only one clinically approved pharmacological treatment option, N-acetylcysteine. N-acetylcysteine increases the cell's antioxidant defense and protects liver cells from further acetaminophen-induced oxidative damage. Because it primarily protects healthy liver cells rather than rescuing the already injured cells alternative treatment strategies that target the latter cell population are warranted. In this study, we investigated mitochondria as therapeutic target for the development of novel treatment strategies for acetaminophen-induced liver injury. Characterization of the mitochondrial toxicity due to acute acetaminophen overdose in vitro in human cells using detailed respirometric analysis revealed that complex I-linked (NADH-dependent) but not complex II-linked (succinate-dependent) mitochondrial respiration is inhibited by acetaminophen. Treatment with a novel cell-permeable succinate prodrug rescues acetaminophen-induced impaired mitochondrial respiration. This suggests cell-permeable succinate prodrugs as a potential alternative treatment strategy to counteract acetaminophen-induced liver injury.


Assuntos
Acetaminofen/efeitos adversos , Analgésicos não Entorpecentes/efeitos adversos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Respiração Celular/efeitos dos fármacos , Overdose de Drogas/tratamento farmacológico , Mitocôndrias/metabolismo , Pró-Fármacos/farmacocinética , Ácido Succínico/farmacocinética , Acetaminofen/administração & dosagem , Acetaminofen/farmacologia , Idoso , Analgésicos não Entorpecentes/administração & dosagem , Analgésicos não Entorpecentes/farmacologia , Plaquetas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Overdose de Drogas/metabolismo , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Células Hep G2 , Hepatócitos/metabolismo , Humanos , Masculino , Mitocôndrias/efeitos dos fármacos
5.
PLoS One ; 15(4): e0226862, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32287270

RESUMO

SESN2 is a member of the evolutionarily conserved sestrin protein family found in most of the Metazoa species. The SESN2 gene is transcriptionally activated by many stress factors, including metabolic derangements, reactive oxygen species (ROS), and DNA-damage. As a result, SESN2 controls ROS accumulation, metabolism, and cell viability. The best-known function of SESN2 is the inhibition of the mechanistic target of rapamycin complex 1 kinase (mTORC1) that plays a central role in support of cell growth and suppression of autophagy. SESN2 inhibits mTORC1 activity through interaction with the GATOR2 protein complex preventing an inhibitory effect of GATOR2 on the GATOR1 protein complex. GATOR1 stimulates GTPase activity of the RagA/B small GTPase, the component of RagA/B:RagC/D complex, preventing mTORC1 translocation to the lysosomes and its activation by the small GTPase Rheb. Despite the well-established role of SESN2 in mTORC1 inhibition, other SESN2 activities are not well-characterized. We recently showed that SESN2 could control mitochondrial function and cell death via mTORC1-independent mechanisms, and these activities might be explained by direct effects of SESN2 on mitochondria. In this work, we examined mitochondrial localization of SESN2 and demonstrated that SESN2 is located on mitochondria and can be directly involved in the regulation of mitochondrial functions.


Assuntos
Mitocôndrias/metabolismo , Proteínas Nucleares/metabolismo , Células A549 , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/metabolismo , Fracionamento Celular , Respiração Celular , Citosol/metabolismo , Humanos , Espécies Reativas de Oxigênio
6.
Am J Physiol Renal Physiol ; 318(5): F1237-F1245, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32223308

RESUMO

Changes in mitochondrial function are central to many forms of kidney disease, including acute injury, diabetic nephropathy, hypertension, and chronic kidney diseases. As such, there is an increasing need for reliable and fast methods for assessing mitochondrial respiratory function in renal cells. Despite being indispensable for many mechanistic studies, cultured cells or isolated mitochondria, however, often do not recapitulate in vivo or close to in vivo situations. Cultured and/or immortalized cells often change their bioenergetic profile and phenotype compared with in vivo or ex vivo situations, and isolated mitochondria are simply removed from their cellular milieu. This is especially important for extremely complex organs such as the kidney. Here, we report the development and validation of a new approach for the rapid assessment of mitochondrial oxygen consumption on freshly isolated glomeruli or proximal tubular fragments using Agilent SeaHorse XFe24 and XF96 Extracellular Flux Analyzers. We validated the technique in several healthy and diseased rodent models: the C57BL/6J mouse, the diabetic db/db mouse and matching db/+ control mouse, and the Dahl salt-sensitive rat. We compared the data to respiration from isolated mitochondria. The method can be adapted and used for the rapid assessment of mitochondrial oxygen consumption from any rodent model of the investigator's choice. The isolation methods presented here ensure viable and functional proximal tubular fragments and glomeruli, with a preserved cellular environment for studying mitochondrial function within the context of their surroundings and interactions.


Assuntos
Diabetes Mellitus/metabolismo , Metabolismo Energético , Hipertensão/metabolismo , Glomérulos Renais/metabolismo , Túbulos Renais Proximais/metabolismo , Mitocôndrias/metabolismo , Animais , Respiração Celular , Diabetes Mellitus/patologia , Modelos Animais de Doenças , Feminino , Hipertensão/patologia , Glomérulos Renais/patologia , Túbulos Renais Proximais/patologia , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/patologia , Consumo de Oxigênio , Ratos Endogâmicos Dahl
7.
PLoS One ; 15(4): e0231267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271800

RESUMO

Women are known to be associated with a higher susceptibility to pulmonary arterial hypertension (PAH). In contrast, male PAH patients have a worse survival prognosis. In this study, we investigated whether the contribution of sex goes beyond the effects of sex hormones by comparing the ability of isolated male and female pulmonary endothelial cells to respire, proliferate and tolerate the stress. Mouse lung endothelial cells (MLEC) were isolated from the lungs of male and female 3-week old mice. Male MLEC showed an increased basal mitochondrial respiration rate, elevated maximal respiration, a significantly greater level of mitochondrial polarization, and a higher rate of proliferation. Exposure of cells to hypoxia (2% of O2 for 24 hours) induced a strong apoptotic response in female but not male MLEC. In contrast, treatment with mitochondrial respiratory Complex III inhibitor Antimycin A (AA, 50µM) mediated severe necrosis specifically in male MLEC, while female cells again responded primarily by apoptosis. The same effect with female cells responding to the stress by apoptosis and male cells responding by necrosis was confirmed in starved pulmonary endothelial cells isolated from human donors. Elevated necrosis seen in male cells was associated with a significant release of damage-associated alarmin, HMGB1. No stimuli induced a significant elevation of HMGB1 secretion in females. We conclude that male cells appear to be protected against mild stress conditions, such as hypoxia, possibly due to increased mitochondrial respiration. In contrast, they are more sensitive to impaired mitochondrial function, to which they respond by necrotic death. Necrosis in male vascular cells releases a significant amount of HMGB1 that could contribute to the pro-inflammatory phenotype known to be associated with the male gender.


Assuntos
Células Endoteliais/metabolismo , Proteína HMGB1/metabolismo , Pulmão/patologia , Caracteres Sexuais , Estresse Fisiológico , Animais , Apoptose , Proliferação de Células , Respiração Celular , Separação Celular , Tamanho Celular , Feminino , Masculino , Potencial da Membrana Mitocondrial , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Necrose
8.
Am J Physiol Regul Integr Comp Physiol ; 318(5): R972-R980, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32233925

RESUMO

Mitochondria utilize the majority of oxygen (O2) consumed by aerobic organisms as the final electron acceptor for oxidative phosphorylation (OXPHOS) but also to generate reactive oxygen species (mtROS) that participate in cell signaling, physiological hormesis, and disease pathogenesis. Simultaneous monitoring of mtROS production and oxygen consumption (Jo2) from tissue mitochondrial preparations is an attractive investigative approach, but it introduces dynamic changes in media O2 concentration ([O2]) that can confound experimental results and interpretation. We utilized high-resolution fluorespirometry to evaluate Jo2 and hydrogen peroxide release (Jh2o2) from isolated mitochondria (Mt), permeabilized fibers (Pf), and tissue homogenates (Hm) prepared from murine heart and skeletal muscle across a range of experimental [O2]s typically encountered during respirometry protocols (400-50 µM). Results demonstrate notable variations in Jh2o2 across tissues and sample preparations during nonphosphorylating (LEAK) and OXPHOS-linked respiration states at 250 µM [O2] but a linear decline in Jh2o2 of 5-15% per 50-µM decrease in chamber [O2] in all samples. Jo2 was generally stable in Mt and Hm across [O2]s above 50 µM but tended to decline below 250 µM in Pf, leading to wide variations in assayed rates of Jh2o2/O2 across chamber [O2]s and sample preparations. Development of chemical background fluorescence from the H2O2 probe (Amplex Red) was also O2 sensitive, emphasizing relevant calibration considerations. This study highlights the importance of monitoring and reporting the chamber [O2] at which Jo2 and Jh2o2 are recorded during fluorespirometry experiments and provides a basis for selecting sample preparations for studies addressing the role of mtROS in physiology and disease.


Assuntos
Peróxido de Hidrogênio/metabolismo , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Miocárdio/metabolismo , Consumo de Oxigênio , Oxigênio/metabolismo , Difosfato de Adenosina/metabolismo , Animais , Respiração Celular , Fluorometria , Cinética , Masculino , Camundongos , Modelos Biológicos , Fosforilação Oxidativa
9.
Chemosphere ; 250: 126223, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32113098

RESUMO

Air quality in large cities has worsened in recent years as a consequence people's health is directly affected. Among the toxic compounds released to environmental air are polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (nitro-PAHs), and oxygenated PAHs (oxy-PAHs). Performant methods to analyze these compounds is necessary to enable adequate monitoring of air quality. Thus, this manuscript presents the development of a highly sensitive method to analyze PAHs, nitro-PAHs, and oxy-PAHs collected from ambient air (PM2.5) and the gas phase for a period of one year in the urban area of Belo Horizonte, Brazil. PAHs and their derivatives were extracted by cold fiber solid phase microextraction (CF-SPME) and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). The proposed method allows simultaneous analysis of 16 PAHs, nitro-PAHs and oxy-PAHs, presenting very good limits of detection and quantification, as well as appropriate precision and recovery. The results obtained for the period of one year allowed different studies. The compounds collected simultaneously from gas and particulate phase showed that total concentration of 16 PAHs were higher in the gas phase than in the particulate. On the other hand, nitro-PAHs and oxy-PAHs presented similar concentration in gas and particulate phases. The potential carcinogenicity of PAHs relative to benzo[a]pyrene showed benzo[a]pyrene equivalents of 0.49 ng m-3. The estimated risk of lifetime lung cancer was 5 × 10-5. Principal component analysis and diagnostic ratio was applied for source distribution indicating that burning of gasoline, diesel and biomass accounted for the PAHs profile in ambient air samples.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluição do Ar/análise , Benzo(a)pireno/análise , Brasil , Respiração Celular , Cidades , Poeira/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Gasolina/análise , Humanos , Nitratos/química , Óxidos de Nitrogênio/análise , Oxigênio/química , Material Particulado/análise , Microextração em Fase Sólida
10.
Plant Biol (Stuttg) ; 22(3): 425-432, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32052535

RESUMO

Cyanide-resistant respiration in potato mitochondria is an important pathway for energy dissipation. It can be activated by high light; however, it is unclear what roles cyanide-resistant respiration plays in the response to high light stress in potato. We designed a CRISPR vector for the functional gene StAOX of the potato cyanide-resistant respiratory pathway. Agrobacterium tumefaciens GV3101 was transformed into potato. Hydrogen peroxide level, MDA content, antioxidant activity and cyanide-resistant respiratory capacity of potato leaves under high light stress were determined. Photosynthetic efficiency and chlorophyll content were determined. In addition, the operation of the malate-oxaloacetate shuttle route and transcription level of photorespiration-related enzymes were also examined. The results showed that two base substitutions occurred at the sequencing target site on leaves of the transformed potato. Accumulation of ROS and increased membrane lipid peroxidation were detected in the transformed potato leaves and lower photosynthetic efficiency was observed. The transcription level of the malate-oxaloacetate shuttle route and photorespiration-related enzymes also significantly increased. These results indicate that the cyanide-resistant respiration is an important physiological pathway in potato in response to high light stress. It also suggests that plant cyanide-resistant respiration is closely related to photosynthesis. This implies the unexplored importance of plant cyanide-resistant respiration in plant photosynthesis, energy conversion and carbon skeleton formation.


Assuntos
Respiração Celular , Cianetos , Resistência a Medicamentos , Luz , Folhas de Planta , Solanum tuberosum , Agrobacterium tumefaciens/genética , Respiração Celular/efeitos dos fármacos , Respiração Celular/efeitos da radiação , Clorofila , Cianetos/toxicidade , Oxirredutases/genética , Fotossíntese , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Solanum tuberosum/efeitos da radiação
11.
PLoS One ; 15(1): e0228106, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978112

RESUMO

We conducted regional scale CO2 simulations using the Weather Research and Forecasting model (WRF) coupled with the Vegetation Photosynthesis and Respiration Model (VPRM). We contrasted simulated concentrations with column, ground and aircraft observations during the Korea-United States Air Quality (KORUS-AQ) 2016 field campaign. Overall, WRF-VPRM slightly underestimates CO2 concentrations at ground and column monitoring sites, but it significantly underestimates at an inland tower measurement site, especially within the stable (nocturnal) boundary layer in nighttime. The model successfully captures the airborne vertical profiles but showed a large offset within the planetary boundary layer (PBL) in the areas surrounding Seoul and around the Taeahn point source emissions in the west coastal area of the Korean Peninsula. A case study flight intended to capture Chinese influence observed no clear signals of long-range transport of CO2, due mainly to the much larger magnitude of background CO2 concentrations. The calculated Net Ecosystem Exchange (NEE) with flux measurements at a tower site in the South Korean Peninsula has also been evaluated comparing with CO2 flux measurements at a flux tower site, resulting in the underestimation by less than a factor of 1.


Assuntos
Dióxido de Carbono/análise , Simulação por Computador , Previsões , Modelos Teóricos , Análise Numérica Assistida por Computador , Fotossíntese , Tempo (Meteorologia) , Aeronaves , Respiração Celular , Ritmo Circadiano , Ecossistema , Geografia , República da Coreia , Seul , Análise Espaço-Temporal , Fatores de Tempo
12.
PLoS One ; 15(1): e0217665, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923248

RESUMO

Olfactory sense remains elusive regarding the primary reception mechanism. Some studies suggest that olfaction is a spectral sense, the olfactory event is triggered by electron transfer (ET) across the odorants at the active sites of odorant receptors (ORs). Herein we present a Donor-Bridge-Acceptor model, proposing that the ET process can be viewed as an electron hopping from the donor molecule to the odorant molecule (Bridge), then hopping off to the acceptor molecule, making the electronic state of the odorant molecule change along with vibrations (vibronic transition). The odorant specific parameter, Huang-Rhys factor can be derived from ab initio calculations, which make the simulation of ET spectra achievable. In this study, we revealed that the emission spectra (after Gaussian convolution) can be acted as odor characteristic spectra. Using the emission spectrum of ET, we were able to reasonably interpret the similar bitter-almond odors among hydrogen cyanide, benzaldehyde and nitrobenzene. In terms of isotope effects, we succeeded in explaining why subjects can easily distinguish cyclopentadecanone from its fully deuterated analogue cyclopentadecanone-d28 but not distinguishing acetophenone from acetophenone-d8.


Assuntos
Percepção Olfatória/genética , Neurônios Receptores Olfatórios/metabolismo , Receptores Odorantes/genética , Olfato/genética , Benzaldeídos/farmacologia , Respiração Celular/genética , Transporte de Elétrons/genética , Humanos , Cianeto de Hidrogênio/farmacologia , Isótopos/farmacologia , Nitrobenzenos/farmacologia , Odorantes/análise , Percepção Olfatória/fisiologia , Neurônios Receptores Olfatórios/química , Receptores Odorantes/metabolismo , Olfato/fisiologia , Vibração
13.
Eur J Vasc Endovasc Surg ; 59(1): 109-115, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31786105

RESUMO

OBJECTIVE: Myopathy, characterised by altered mitochondrial function, is a central part of the pathophysiology of peripheral arterial disease and the aim of this study was to investigate the effect of revascularisation on mitochondrial function. METHODS: High resolution respirometry was used to investigate mitochondrial respiration and the results were normalised to citrate synthase activity (CSA), a marker of mitochondrial content. Ten patients with symptomatic peripheral arterial disease (study group) and 10 subjects without ischaemia (control group) were included. Ankle brachial index and ultrasound imaging were performed before and after vascular intervention to confirm technically successful revascularisation. Within the study group, muscle biopsies from the gastrocnemius muscle were taken before vascular intervention and six weeks after revascularisation. Within the control group, tissue was harvested once. RESULTS: There were no significant group differences regarding anthropometric data. CSA showed a significant increase after successful revascularisation (CSA pre-operative 281.4 (252.4-391.8) nmol/min/mg protein vs. CSA post-operative 438.5 (361.4-471.3) nmol/min/mg protein; p = .01) with post-operative return of values to the range of control subjects (CSA control 396.6 (308.2-435.9)). Mitochondrial respiration normalised to CSA in oxidative phosphorylation (P) as well as in electron transfer (E) capacity were significantly reduced post-operatively when compared with pre-operative values (P pre-operative 0.218 (0.196-0.266) pmol/(sec×mg) per CSA vs. post-operative 0.132 (0.116-0.150) pmol/(sec×mg) per CSA, p = .007; E pre-operative 0.230 (0.195-0.279) pmol/(sec×mg) per CSA vs. post-operative 0.129 (0.120-0.154) pmol/(sec×mg) per CSA, p = .005) meaning a post-operative return of values to within the range of control subjects (P control 0.124 (0.080-0.155) pmol/(sec×mg) per CSA; E control 0.121 (0.079-0.125) pmol/(sec×mg) per CSA). CONCLUSION: With these results, it has been shown that the initially impaired mitochondrial function and content can normalise after revascularisation.


Assuntos
Procedimentos Endovasculares , Mitocôndrias Musculares/fisiologia , Músculo Esquelético/irrigação sanguínea , Doenças Musculares/cirurgia , Doença Arterial Periférica/cirurgia , Adulto , Idoso , Biópsia , Estudos de Casos e Controles , Respiração Celular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/citologia , Músculo Esquelético/patologia , Doenças Musculares/etiologia , Doenças Musculares/patologia , Consumo de Oxigênio/fisiologia , Doença Arterial Periférica/complicações , Regeneração , Resultado do Tratamento
14.
Chemosphere ; 242: 125130, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31669996

RESUMO

Identifying co-metabolic TCE oxidation in polluted groundwater is challenging due to lack of indicative by-products. This challenge may theoretically be resolved if the oxidation process can be characterized by a distinct dual isotope enrichment. In this work, we aimed to explore the carbon and chlorine isotope effects associated with TCE oxidation by a variety of oxygenases. These included pure strains and enrichment cultures of methane, toluene and ammonia oxidizers, as well as experiments with crude extracts. Isotope effects determined for TCE oxidation by toluene and ammonia oxidizers were mostly in line with expected values for epoxidation mechanism (ϵ13C -11.0 ±â€¯0.7 to -24.8 ±â€¯0.2‰ and ϵ37Cl +0.9 ± 0.5 to +1.0 ± 0.4‰), whereas, the methanotrophs resulted in distinctively different isotope effects (ϵ13C -2.4 ±â€¯0.4 to -3.4 ±â€¯0.8‰ and ϵ37Cl -1.8 ±â€¯0.2 to -2.9 ±â€¯0.9‰). It is suggested that in TCE oxidation by methanotrophs, substrate binding rather than bond cleavage is rate limiting, leading to this unexpected isotope effect. On the environmental level, our results imply that the oxidative process can be differentiated if catalyzed by toluene and ammonia oxidizers or by methanotrophs. Additionally, the oxidative process can be distinguished from the reductive one. However, using dual isotope analysis in the field may result in an under-estimation of the overall co-metabolic process if methanotrophs are to be excluded due to low isotope effects.


Assuntos
Biodegradação Ambiental , Cloro/metabolismo , Tricloroetileno/metabolismo , Poluentes Químicos da Água/metabolismo , Carbono , Isótopos de Carbono/análise , Respiração Celular , Fracionamento Químico , Cloro/química , Poluição Ambiental/análise , Água Subterrânea/química , Metano , Tricloroetileno/química , Poluentes Químicos da Água/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-31712185

RESUMO

Toxaphene is a restricted-use pesticide produced by reacting chlorine gas with camphene. It was heavily used as a pesticide for agricultural purposes in the 1960-1970s, but despite being banned >30 years ago, it can remain elevated in the soil due to its resistance to metabolic degradation; this has led to longstanding concerns about elevated levels of toxaphene and other organochlorine pesticides (OCPs) in the environment. The objective of this study were to determine the effects of waterborne exposure to toxaphene on early life stages of zebrafish. Based on the LC50, zebrafish embryos were exposed to control (embryo rearing media or DMSO) or to one dose of toxaphene ranging between 0.011 and 111.1 µg/mL from 6 h post fertilization (hpf) up to 120 hpf. Significant mortality and hatch time delays were observed in embryos exposed to toxaphene (at or above 0.11 and 1.11 µg/mL, depending on the assay). Higher prevalence of deformities was noted at higher doses (≥0.011 µg/mL), and these included pericardial edema and skeletal deformities. As energy production is important for normal development, mitochondrial bioenergetics were assessed in embryos following toxaphene exposure. Embryos exposed to 11.1 or 111 µg/mL toxaphene for 24 h showed lower non-mitochondrial respiration (~30%) compared to both solvent and no treatment controls. Expression of transcripts related to oxidative damage responses and apoptosis were measured and heat shock protein 70 was significantly increased with 111 µg/mL toxaphene (14.5 fold), while the expression levels of caspase 3, caspase 9, and superoxide dismutase 1 were not changed. These data demonstrate that developmental deformities induced by toxaphene include pericardial edema and skeletal deformity, and that toxaphene can affect oxidative phosphorylation in early staged zebrafish.


Assuntos
Proteínas de Choque Térmico HSP70/metabolismo , Mitocôndrias/metabolismo , Praguicidas/toxicidade , Toxafeno/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Animais , Respiração Celular/efeitos dos fármacos , Larva/metabolismo , Estresse Oxidativo
16.
Glob Chang Biol ; 26(3): 1739-1753, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31578796

RESUMO

Two simplifying hypotheses have been proposed for whole-plant respiration. One links respiration to photosynthesis; the other to biomass. Using a first-principles carbon balance model with a prescribed live woody biomass turnover, applied at a forest research site where multidecadal measurements are available for comparison, we show that if turnover is fast the accumulation of respiring biomass is low and respiration depends primarily on photosynthesis; while if turnover is slow the accumulation of respiring biomass is high and respiration depends primarily on biomass. But the first scenario is inconsistent with evidence for substantial carry-over of fixed carbon between years, while the second implies far too great an increase in respiration during stand development-leading to depleted carbohydrate reserves and an unrealistically high mortality risk. These two mutually incompatible hypotheses are thus both incorrect. Respiration is not linearly related either to photosynthesis or to biomass, but it is more strongly controlled by recent photosynthates (and reserve availability) than by total biomass.


Assuntos
Carbono , Fotossíntese , Biomassa , Dióxido de Carbono , Respiração Celular , Florestas , Folhas de Planta , Árvores
17.
Metabolism ; 103: 154048, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31843339

RESUMO

OBJECTIVE: Angiotensin-(1-7) [Ang-(1-7)], a component of the renin angiotensin system, is a vasodilator that exerts its effects primarily through the Mas receptor. The discovery of the Mas receptor in white adipose tissue (WAT) suggests an additional role for this peptide. The aim of the present study was to assess whether Ang-(1-7) can induce the expression of thermogenic genes in white adipose tissue and increase mitochondrial respiration in adipocytes. MATERIALS/METHODS: Stromal Vascular fraction (SVF)-derived from mice adipose tissue was stimulated for one week with Ang-(1-7), then expression of beige markers and mitochondrial respiration were assessed. Mas+/+ and Mas-/- mice fed a control diet or a high fat-sucrose diet (HFSD) were exposed to a short or long term infusion of Ang-(1-7) and body weight, body fat, energy expenditure, cold resistance and expression of beige markers were assessed. Also, transgenic rats overexpressing Ang-(1-7) were fed with a control diet or a high fat-sucrose diet and the same parameters were assessed. Ang-(1-7) circulating levels from human subjects with different body mass index (BMI) or age were measured. RESULTS: Incubation of adipocytes derived from SVF with Ang-(1-7) increased the expression of beige markers. Infusion of Ang-(1-7) into lean and obese Mas+/+mice also induced the expression of Ucp1 and some beige markers, an effect not observed in Mas-/- mice. Mas-/- mice had increased body weight gain and decreased cold resistance, whereas rats overexpressing Ang-(1-7) showed the opposite effects. Overexpressing rats exposed to cold developed new thermogenic WAT in the anterior interscapular area. Finally, in human subjects the higher the BMI, low circulating concentration of Ang-(1-7) levels were detected. Similarly, the circulating levels of Ang-(1-7) peptide were reduced with age. CONCLUSION: These data indicate that Ang-(1-7) stimulates beige markers and thermogenesis via the Mas receptor, and this evidence suggests a potential therapeutic use to induce thermogenesis of WAT, particularly in obese subjects that have reduced circulating concentration of Ang-(1-7).


Assuntos
Tecido Adiposo Bege/efeitos dos fármacos , Angiotensina I/farmacologia , Fragmentos de Peptídeos/farmacologia , Proteínas Proto-Oncogênicas/fisiologia , Receptores Acoplados a Proteínas-G/fisiologia , Termogênese/efeitos dos fármacos , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Adulto , Animais , Respiração Celular/efeitos dos fármacos , Respiração Celular/genética , Células Cultivadas , Metabolismo Energético/genética , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , Proteínas Proto-Oncogênicas/genética , Ratos , Ratos Transgênicos , Receptores Acoplados a Proteínas-G/genética , Termogênese/genética , Adulto Jovem
18.
Int J Mol Sci ; 20(24)2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31835667

RESUMO

Based on the potential therapeutic value in targeting metabolism for the treatment of cancer, an organic arsenical PDT-BIPA was fabricated, which exerted selective anti-cancer activity in vitro and in vivo via targeting lactate dehydrogenase A (LDHA) to remodel the metabolic pathway. In details, the precursor PDT-BIPA directly inhibited the function of LDHA and converted the glycolysis to oxidative phosphorylation causing ROS burst and mitochondrial dysfunction. PDT-BIPA also altered several gene expression, such as HIF-1α and C-myc, to support the metabolic remodeling. All these changes lead to caspase family-dependent cell apoptosis in vivo and in vitro without obvious side effect. Our results provided this organic arsenical precursor as a promising anticancer candidate and suggested metabolism as a target for cancer therapies.


Assuntos
Arsenicais/farmacologia , Progressão da Doença , Lactato Desidrogenase 5/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Compostos Orgânicos/farmacologia , Animais , Arsenicais/síntese química , Arsenicais/química , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Respiração Celular/efeitos dos fármacos , Feminino , Glutationa/metabolismo , Humanos , Antígeno Ki-67/metabolismo , Lactato Desidrogenase 5/antagonistas & inibidores , Camundongos Nus , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Compostos Orgânicos/síntese química , Compostos Orgânicos/química , Consumo de Oxigênio/efeitos dos fármacos , Complexo Piruvato Desidrogenase/metabolismo , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Tiorredoxinas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
19.
PLoS One ; 14(12): e0225954, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31821369

RESUMO

The reduction of 2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride (INT) is increasingly being used as an indirect method to measure plankton respiration. Its greater sensitivity and shorter incubation time compared to the standard method of measuring the decrease in dissolved oxygen concentration, allows the determination of total and size-fractionated plankton respiration with higher precision and temporal resolution. However, there are still concerns as to the method's applicability due to the toxicity of INT and the potential differential effect of plankton cell wall composition on the diffusion of INT into the cell, and therefore on the rate of INT reduction. Working with cultures of 5 marine plankton (Thalassiosira pseudonana CCMP1080/5, Emiliania huxleyi RCC1217, Pleurochrysis carterae PLY-406, Scrippsiella sp. RCC1720 and Oxyrrhis marina CCMP1133/5) which have different cell wall compositions (silica frustule, presence/absence of calcite and cellulose plates), we demonstrate that INT does not have a toxic effect on oxygen consumption at short incubation times. There was no difference in the oxygen consumption of a culture to which INT had been added and that of a replicate culture without INT, for periods of time ranging from 1 to 7 hours. For four of the cultures (T. pseudonana CCMP1080/5, P. carterae PLY-406, E. huxleyi RCC1217, and O. marina CCMP1133/5) the log of the rates of dissolved oxygen consumption were linearly related to the log of the rates of INT reduction, and there was no significant difference between the regression lines for each culture (ANCOVA test, F = 1.696, df = 3, p = 0.18). Thus, INT reduction is not affected by the structure of the plankton cell wall and a single INT reduction to oxygen consumption conversion equation is appropriate for this range of eukaryotic plankton. These results further support the use of the INT technique as a valid proxy for marine plankton respiration.


Assuntos
Respiração Celular , Parede Celular/metabolismo , Plâncton/fisiologia , Sais de Tetrazólio/análise , Algoritmos , Parede Celular/química , Parede Celular/ultraestrutura , Modelos Teóricos , Oxirredução , Consumo de Oxigênio , Sais de Tetrazólio/metabolismo , Sais de Tetrazólio/toxicidade
20.
Oxid Med Cell Longev ; 2019: 6521218, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885809

RESUMO

Diabetic cardiomyopathy (DCM) is one of the common cardiovascular complications in patients with diabetes. Accumulating evidence has demonstrated that DCM is thoroughly related to mitochondrial energy impairment and increases the generation of reactive oxygen species (ROS). Therefore, an ongoing study is developing strategies to protect cardiac mitochondria from diabetic complications, especially from hyperglycemia. Phosphocreatine (PCr) plays a major metabolic role in cardiac muscular cells including intracellular concentration of ATP which affects the activity of the myocardium. We hypothesized that PCr might improve oxidative phosphorylation and electron transport capacity in mitochondria impaired by hyperglycemia in vivo and in vitro. Also, we aimed to evaluate the protective effect of PCr against DCM through the JAK2/STAT3 signaling pathway. The mitochondrial respiratory capacity from rats and H9C2 cells was measured by high-resolution respirometry (HRR). Expressions of proteins Bax, Bcl-2, caspase 3, caspase 9, cleaved caspase 3, and cleaved caspase 9, as well as JAK2/STAT3 signaling pathways, were determined by western blotting. ROS generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. Type 1 diabetes mellitus was induced in Wistar male rats by a single intraperitoneal injection of streptozotocin (STZ) (80 mg/kg body weight). Our results revealed that PCr possessed protective effects against DCM injury by improving the mitochondrial bioenergetics and by positively exerting protective effects against DCM in vivo and in vitro, not only improving diabetes symptom, resulting in changes of cardiac tissue using hematoxylin and eosin (H&E) stain, but also ameliorating biochemical changes. Moreover, PCr increased Bcl-2, caspase 3, and caspase 9 protein expressions and decreased Bax, cleaved caspase 3, and cleaved caspase 9 expressions as well as the JAK2/STAT3 signaling pathway. In conclusion, PCr improves mitochondrial functions and exerts an antiapoptotic effect in vivo and in vitro exposed to oxidative stress by hyperglycemia through the JAK2/STAT3 signaling pathway. Our findings suggest that PCr medication is a possible therapeutic strategy for cardioprotection.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Mitocôndrias Cardíacas/metabolismo , Miocárdio/metabolismo , Fosfocreatina/metabolismo , Animais , Linhagem Celular , Respiração Celular , Humanos , Janus Quinase 2/metabolismo , Masculino , Potencial da Membrana Mitocondrial , Miocárdio/patologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais
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