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1.
Blood ; 143(18): 1807-1815, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38237147

RESUMO

ABSTRACT: Caplacizumab prevents the interaction between von Willebrand factor and platelets and is used to treat immune thrombotic thrombocytopenic purpura (iTTP). Its administration has been associated with a delay in ADAMTS13 activity restoration after plasma exchange (PEX) suspension. We analyzed the outcomes of 113 iTTP episodes, 75 of which were treated with caplacizumab, in 108 patients from the Spanish Registry of Thrombotic Thrombocytopenic Purpura. Caplacizumab shortened the time to platelet count normalization and reduced PEX requirement, exacerbations, and relapses. There was no difference in the time to achieve ADAMTS13 activity ≥20% after PEX end between caplacizumab-treated and nontreated episodes (median [interquartile range], 14.5 [7.7-27.2] vs 13.0 [8.0-29.0] days, P = .653). However, considering the 36 episodes in which caplacizumab was started ≤3 days after iTTP diagnosis, the time for ADAMTS13 restoration from PEX end was higher than in those episodes in which caplacizumab was started >3 days after iTTP diagnosis (20.0 [12.0-43.0] vs 11.0 [3.5-20.0] days, P = .003) or than in non-caplacizumab-treated episodes (P = .033). This finding could be related to a significantly shorter duration of PEX in early caplacizumab-treated episodes than in late caplacizumab-treated episodes (5.5 [4.0-9.0] vs 15.0 [11.0-21.5] days, P < .001) or non-caplacizumab-treated episodes (11.0 [6.0-26.0] days, P < .001). There were no differences in time to ADAMTS-13 restoration from PEX start (28.0 [17.2-47.5], 27.0 [19.0-37.5] and 29.5 [15.2-45.0] days in early caplacizumab-treated, late caplacizumab-treated and non-caplacizumab-treated episodes). Early administered caplacizumab does not prevent the requirement for immunosuppression but has beneficial effects by shortening PEX requirement without major safety concerns.


Assuntos
Proteína ADAMTS13 , Troca Plasmática , Púrpura Trombocitopênica Trombótica , Anticorpos de Domínio Único , Humanos , Proteína ADAMTS13/sangue , Proteína ADAMTS13/metabolismo , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/terapia , Masculino , Feminino , Anticorpos de Domínio Único/uso terapêutico , Adulto , Pessoa de Meia-Idade , Contagem de Plaquetas , Doença Aguda , Resultado do Tratamento , Idoso
2.
Proc Natl Acad Sci U S A ; 119(6)2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35115403

RESUMO

Photosystem II (PSII), the water/plastoquinone photo-oxidoreductase, plays a key energy input role in the biosphere. [Formula: see text], the reduced semiquinone form of the nonexchangeable quinone, is often considered capable of a side reaction with O2, forming superoxide, but this reaction has not yet been demonstrated experimentally. Here, using chlorophyll fluorescence in plant PSII membranes, we show that O2 does oxidize [Formula: see text] at physiological O2 concentrations with a t1/2 of 10 s. Superoxide is formed stoichiometrically, and the reaction kinetics are controlled by the accessibility of O2 to a binding site near [Formula: see text], with an apparent dissociation constant of 70 ± 20 µM. Unexpectedly, [Formula: see text] could only reduce O2 when bicarbonate was absent from its binding site on the nonheme iron (Fe2+) and the addition of bicarbonate or formate blocked the O2-dependant decay of [Formula: see text] These results, together with molecular dynamics simulations and hybrid quantum mechanics/molecular mechanics calculations, indicate that electron transfer from [Formula: see text] to O2 occurs when the O2 is bound to the empty bicarbonate site on Fe2+ A protective role for bicarbonate in PSII was recently reported, involving long-lived [Formula: see text] triggering bicarbonate dissociation from Fe2+ [Brinkert et al, Proc. Natl. Acad. Sci. U.S.A. 113, 12144-12149 (2016)]. The present findings extend this mechanism by showing that bicarbonate release allows O2 to bind to Fe2+ and to oxidize [Formula: see text] This could be beneficial by oxidizing [Formula: see text] and by producing superoxide, a chemical signal for the overreduced state of the electron transfer chain.


Assuntos
Bicarbonatos/metabolismo , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Chlamydomonas reinhardtii/metabolismo , Clorofila/metabolismo , Transporte de Elétrons/fisiologia , Formiatos/metabolismo , Oxirredução , Quinonas/metabolismo , Spinacia oleracea/metabolismo
3.
J Am Chem Soc ; 146(26): 18019-18031, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38888987

RESUMO

The membrane-bound hydrogenase (Mbh) from Pyrococcus furiosus is an archaeal member of the Complex I superfamily. It catalyzes the reduction of protons to H2 gas powered by a [NiFe] active site and transduces the free energy into proton pumping and Na+/H+ exchange across the membrane. Despite recent structural advances, the mechanistic principles of H2 catalysis and ion transport in Mbh remain elusive. Here, we probe how the redox chemistry drives the reduction of the proton to H2 and how the catalysis couples to conformational dynamics in the membrane domain of Mbh. By combining large-scale quantum chemical density functional theory (DFT) and correlated ab initio wave function methods with atomistic molecular dynamics simulations, we show that the proton transfer reactions required for the catalysis are gated by electric field effects that direct the protons by water-mediated reactions from Glu21L toward the [NiFe] site, or alternatively along the nearby His75L pathway that also becomes energetically feasible in certain reaction steps. These local proton-coupled electron transfer (PCET) reactions induce conformational changes around the active site that provide a key coupling element via conserved loop structures to the ion transport activity. We find that H2 forms in a heterolytic proton reduction step, with spin crossovers tuning the energetics along key reaction steps. On a general level, our work showcases the role of electric fields in enzyme catalysis and how these effects are employed by the [NiFe] active site of Mbh to drive PCET reactions and ion transport.


Assuntos
Hidrogênio , Hidrogenase , Simulação de Dinâmica Molecular , Pyrococcus furiosus , Hidrogenase/química , Hidrogenase/metabolismo , Hidrogênio/química , Hidrogênio/metabolismo , Pyrococcus furiosus/enzimologia , Prótons , Teoria da Densidade Funcional , Domínio Catalítico , Oxirredução
4.
Anal Chem ; 96(15): 5790-5797, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38452224

RESUMO

Nanoplastic particles are emerging as an important class of environmental pollutants in the atmosphere that have adverse effects on our ecosystems and human health. While many methods have been developed to quantitatively detect nanoplastics; however, sensitive detection at low concentrations in a complex environment remains elusive. Herein, we demonstrate a greener method to fabricate a surface-enhanced Raman spectroscopy (SERS) substrate consisting of self-assembled plasmonic Ag-Au bimetallic nanoparticle (NP) films for quantitative SERS detection of nanoplastics in complex media. The self-assembly of Ag-Au bimetallic NPs was achieved through thermal evaporation onto a vapor-phase compatible ionic liquid based on deep eutectic solvent over the growth substrate. The finite-difference time-domain simulation revealed that the localized field enhancement is strong in the gaps, which generate uniform SERS "hotspots" in the obtained substrate. Benefiting from highly accessible SERS "hotspots" at the gaps, the SERS substrate exhibits excellent sensitivity for detecting crystal violet with a limit of detection (LOD) as low as 10-14 M and excellent reproducibility (RSD of 5.8%). The SERS substrate is capable of detecting PET nanoplastics with LOD as low as 1 µg/mL and about 100 µg/mL in real samples such as tap water, lake water, diluted milk, and wine. Moreover, we also validated the feasibility of the designed SERS substrate for the practical detection of PET nanoplastics collected from commercial drinking water bottles, and it showed great potential applications for sensitive detection in actual environments.

5.
Immunol Cell Biol ; 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38873699

RESUMO

Antibiotic resistance is a major public health threat, and alternatives to antibiotic therapy are urgently needed. Immunotherapy, particularly the blockade of inhibitory immune checkpoints, is a leading treatment option in cancer and autoimmunity. In this study, we used a murine model of Salmonella Typhimurium infection to investigate whether immune checkpoint blockade could be applied to bacterial infection. We found that the immune checkpoint T-cell immunoglobulin and ITIM domain (TIGIT) was significantly upregulated on lymphocytes during infection, particularly on CD4+ T cells, drastically limiting their proinflammatory function. Blockade of TIGIT in vivo using monoclonal antibodies was able to enhance immunity and improve bacterial clearance. The efficacy of anti-TIGIT was dependent on the capacity of the antibody to bind to Fc (fragment crystallizable) receptors, giving important insights into the mechanism of anti-TIGIT therapy. This research suggests that targeting immune checkpoints, such as TIGIT, has the potential to enhance immune responses toward bacteria and restore antibacterial treatment options in the face of antibiotic resistance.

6.
Am J Kidney Dis ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38866126

RESUMO

Monkeypox (mpox) is an orthopoxviral zoonotic disease with a similar, but less severe, clinical presentation as smallpox. However, immunocompromised patients such as solid organ transplant recipients are at higher risk of developing severe forms of the disease. Herein, we describe the case of a 43 years-old female kidney transplant recipient that manifested severe skin ulcers alongside nodular lung opacities and pleural effusion attributed directly to the Monkeypox virus. Notwithstanding the initiation of early treatment with tecovirimat, a satisfactory response was not achieved until a reduction in immunosuppression to everolimus monotherapy, coupled with the transition to cidofovir for antiviral treatment. In conclusion, mpox has the potential to produce a severe form of systemic infection in individuals who have undergone solid organ transplantation, demanding a meticulous approach involving sequential antiviral treatment and modifications to immunosuppressive regimens in order to achieve complete healing.

7.
Plant Physiol ; 191(3): 1596-1611, 2023 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-36527697

RESUMO

Resistance to cucumber mosaic virus (CMV) in melon (Cucumis melo L.) has been described in several exotic accessions and is controlled by a recessive resistance gene, cmv1, that encodes a vacuolar protein sorting 41 (CmVPS41). cmv1 prevents systemic infection by restricting the virus to the bundle sheath cells, preventing viral phloem entry. CmVPS41 from different resistant accessions carries two causal mutations, either a G85E change, found in Pat-81 and Freeman's cucumber, or L348R, found in PI161375, cultivar Songwhan Charmi (SC). Here, we analyzed the subcellular localization of CmVPS41 in Nicotiana benthamiana and found differential structures in resistant and susceptible accessions. Susceptible accessions showed nuclear and membrane spots and many transvacuolar strands, whereas the resistant accessions showed many intravacuolar invaginations. These specific structures colocalized with late endosomes. Artificial CmVPS41 carrying individual mutations causing resistance in the genetic background of CmVPS41 from the susceptible variety Piel de Sapo (PS) revealed that the structure most correlated with resistance was the absence of transvacuolar strands. Coexpression of CmVPS41 with viral movement proteins, the determinant of virulence, did not change these localizations; however, infiltration of CmVPS41 from either SC or PS accessions in CMV-infected N. benthamiana leaves showed a localization pattern closer to each other, with up to 30% cells showing some membrane spots in the CmVPS41SC and fewer transvacuolar strands (reduced from a mean of 4 to 1-2) with CmVPS41PS. Our results suggest that the distribution of CmVPS41PS in late endosomes includes transvacuolar strands that facilitate CMV infection and that CmVPS41 re-localizes during viral infection.


Assuntos
Cucumovirus , Infecções por Citomegalovirus , Humanos , Cucumovirus/genética , Genes de Plantas , Proteínas Virais/metabolismo , Mutação/genética , Infecções por Citomegalovirus/genética , Doenças das Plantas/genética
8.
J Inherit Metab Dis ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38973597

RESUMO

The protein encoded by COQ7 is required for CoQ10 synthesis in humans, hydroxylating 3-demethoxyubiquinol (DMQ10) in the second to last steps of the pathway. COQ7 mutations lead to a primary CoQ10 deficiency syndrome associated with a pleiotropic neurological disorder. This study shows the clinical, physiological, and molecular characterization of four new cases of CoQ10 primary deficiency caused by five mutations in COQ7, three of which have not yet been described, inducing mitochondrial dysfunction in all patients. However, the specific combination of the identified variants in each patient generated precise pathophysiological and molecular alterations in fibroblasts, which would explain the differential in vitro response to supplementation therapy. Our results suggest that COQ7 dysfunction could be caused by specific structural changes that affect the interaction with COQ9 required for the DMQ10 presentation to COQ7, the substrate access to the active site, and the maintenance of the active site structure. Remarkably, patients' fibroblasts share transcriptional remodeling, supporting a modification of energy metabolism towards glycolysis, which could be an adaptive mechanism against CoQ10 deficiency. However, transcriptional analysis of mitochondria-associated pathways showed distinct and dramatic differences between patient fibroblasts, which correlated with the extent of pathophysiological and neurological alterations observed in the probands. Overall, this study suggests that the combination of precise genetic diagnostics and the availability of new structural models of human proteins could help explain the origin of phenotypic pleiotropy observed in some genetic diseases and the different responses to available therapies.

9.
J Chem Inf Model ; 64(4): 1229-1244, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38356237

RESUMO

Food chemicals have a fundamental role in our lives, with an extended impact on nutrition, disease prevention, and marked economic implications in the food industry. The number of food chemical compounds in public databases has substantially increased in the past few years, which can be characterized using chemoinformatics approaches. We and other groups explored public food chemical libraries containing up to 26,500 compounds. This study aimed to analyze the chemical contents, diversity, and coverage in the chemical space of food chemicals and additives and, from here on, food components. The approach to food components addressed in this study is a public database with more than 70,000 compounds, including those predicted via omics techniques. It was concluded that food components have distinctive physicochemical properties and constitutional descriptors despite sharing many chemical structures with natural products. Food components, on average, have large molecular weights and several apolar structures with saturated hydrocarbons. Compared to reference databases, food component structures have low scaffold and fingerprint-based diversity and high structural complexity, as measured by the fraction of sp3 carbons. These structural features are associated with a large fraction of macronutrients as lipids. Lipids in food components were decompiled by an analysis of the maximum common substructures. The chemical multiverse representation of food chemicals showed a larger coverage of chemical space than natural products and FDA-approved drugs by using different sets of representations.


Assuntos
Produtos Biológicos , Bases de Dados Factuais , Produtos Biológicos/química , Lipídeos
10.
J Asthma ; : 1-4, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38639468

RESUMO

INTRODUCTION: Mounier-Kuhn syndrome or tracheobronchomegaly, is a rare condition that consists of abnormal dilation of the trachea and main bronchi due to a pathological arrangement of smooth muscle fibers in this area. CASE REPORT: We present the case of a 46-year-old woman with poorly controlled asthma and recurrent infections, who was diagnosed with Mounier-Kuhn syndrome through a computed tomography scan revealing an unusual enlargement of the trachea with associated bronchiectasis. RESULTS: The diagnosis of Mounier-Kuhn syndrome is radiological, involving measurement of the trachea where a diameter >25 mm in men and >21 mm in women is observed. While diagnosis is sometimes incidental, there is an association with respiratory diseases such as asthma or COPD, hence clinical suspicion is important in patients with poorly controlled underlying conditions who present with recurrent infections, inadequate secretion management, or even hemoptysis. CONCLUSIONS: Despite its rarity, this syndrome significantly impacts patients' quality of life. Diagnosis and management involve comprehensive evaluations including computed tomography, with a multidisciplinary approach including pulmonologists and radiologists. Exploring its clinical features, associations with other respiratory diseases and treatment options is crucial in managing this rare respiratory condition.

11.
Neurol Sci ; 45(8): 3879-3886, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38494461

RESUMO

BACKGROUND: This study sought to determine whether intensive blood pressure (BP) control for patients with successful reperfusion following acute ischemic stroke (AIS) is beneficial, compared to conventional BP management. METHODS: PubMed, Embase, and Cochrane databases were systematically searched for randomized controlled trials (RCTs) on the subject. The studied outcomes included dependency or death at 90 days (modified Rankin Scale [mRS] 3-6); severe disability at 90 days (mRS 3-5); mortality at 90 days; and symptomatic intracranial hemorrhage. Odds ratios (OR) with 95% confidence intervals were used to compare the treatment effects for categorical outcomes. We employed a fixed-effect model for analyses with low heterogeneity (I2 < 25%) and a random-effects model for analyses with higher heterogeneity. RESULTS: A total of 1519 patients were included, with 50% (n = 760) receiving intensive BP control (systolic BP < 140 mmHg). Functional disability or death at 90 days was significantly higher in the intensive group (54.9%) compared to the conventional treatment group (44.1%) (OR = 1.51; 95% Confidence Interval [CI]: 1.15-1.96; p = 0.003; I2 = 29%). Severe functional disability (mRS 3-5) was significantly higher in the intensive group (30.6% vs. 43.5%, OR = 1.75; 95%CI = 1.36-2.25; p < 0.0001; I2 = 0%). There was no difference in symptomatic intracranial hemorrhage (OR = 1.13; 95%CI = 0.76-1.67) or mortality (OR = 1.22; 95%CI = 0.9-1.64). CONCLUSIONS: Intensive BP control is harmful in patients who underwent EVT for AIS and achieved successful reperfusion. It yields higher rates of functional dependence, with no differences in mortality or symptomatic intracranial hemorrhage.


Assuntos
Pressão Sanguínea , AVC Isquêmico , Ensaios Clínicos Controlados Aleatórios como Assunto , Reperfusão , Humanos , AVC Isquêmico/terapia , AVC Isquêmico/cirurgia , Pressão Sanguínea/fisiologia , Reperfusão/métodos , Trombectomia/métodos
12.
Proc Natl Acad Sci U S A ; 118(29)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34272275

RESUMO

Cellular respiration is powered by membrane-bound redox enzymes that convert chemical energy into an electrochemical proton gradient and drive the energy metabolism. By combining large-scale classical and quantum mechanical simulations with cryo-electron microscopy data, we resolve here molecular details of conformational changes linked to proton pumping in the mammalian complex I. Our data suggest that complex I deactivation blocks water-mediated proton transfer between a membrane-bound quinone site and proton-pumping modules, decoupling the energy-transduction machinery. We identify a putative gating region at the interface between membrane domain subunits ND1 and ND3/ND4L/ND6 that modulates the proton transfer by conformational changes in transmembrane helices and bulky residues. The region is perturbed by mutations linked to human mitochondrial disorders and is suggested to also undergo conformational changes during catalysis of simpler complex I variants that lack the "active"-to-"deactive" transition. Our findings suggest that conformational changes in transmembrane helices modulate the proton transfer dynamics by wetting/dewetting transitions and provide important functional insight into the mammalian respiratory complex I.


Assuntos
Complexo I de Transporte de Elétrons/química , Complexo I de Transporte de Elétrons/metabolismo , Prótons , Animais , Sítios de Ligação , Transporte Biológico , Respiração Celular , Microscopia Crioeletrônica , Complexo I de Transporte de Elétrons/genética , Metabolismo Energético , Humanos , Doenças Mitocondriais/genética , Membranas Mitocondriais/química , Membranas Mitocondriais/metabolismo , Simulação de Dinâmica Molecular , Mutação , Oxirredução , Conformação Proteica , Domínios Proteicos , Estrutura Secundária de Proteína , Quinonas/química , Quinonas/metabolismo , Água/química , Água/metabolismo
13.
Odontology ; 112(1): 185-199, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37378834

RESUMO

Periodontitis is an oral-cavity inflammatory disease and is the principal cause associated with tooth loss. Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are important proteases involved in periodontal tissue destruction. The omega-3 polyunsaturated fatty acids (ω-3 PUFA) have been demonstrated to possess immunoregulatory properties in periodontitis. The aim of the study was to investigate the effects of ω-3 PUFA on inflammation and on the expression of MMP-2 and -9 in a murine periodontitis model. Twenty-four male C57BL/6 mice were divided into control mice (Control), control mice treated with ω-3 PUFA (O3), mice with periodontitis (P), and mice with periodontitis treated with ω-3 PUFA (P + O3). ω-3 PUFA were administered orally once a day for 70 days. Periodontitis in mice was induced by Porphyromonas gingivalis-infected ligature placement around the second maxillary molar. The mice were sacrificed, and blood and maxillary samples were collected. Flow cytometry was used to quantify tumor necrosis factor-alpha (TNFα), interleukin (IL)-2, IL-4, IL-5, and interferon-gamma. Histologic analysis and immunohistochemistry for MMP-2 and -9 were performed. The data were statistically evaluated using analysis of variance (ANOVA) and the Tukey post hoc test. Histological analysis showed that ω-3 PUFA supplementation prevented inflammation and tissue destruction and revealed that bone destruction was more extensive in the P group than in the P + O3 group (p < 0.05). Also, it decreased the serum expressions of TNFα and IL-2 and the tissue expression of MMP-2 and -9 in the periodontitis-induced model (p < 0.05). ω-3 PUFA supplementation prevented alveolar bone loss and periodontal destruction, probably by decreasing the expression of MMP-2 and MMP-9 and its immunoregulatory properties.


Assuntos
Ácidos Graxos Ômega-3 , Periodontite , Camundongos , Masculino , Animais , Metaloproteinase 2 da Matriz , Metaloproteinase 9 da Matriz , Ácidos Graxos Ômega-3/farmacologia , Modelos Animais de Doenças , Fator de Necrose Tumoral alfa , Camundongos Endogâmicos C57BL , Periodontite/tratamento farmacológico , Periodontite/prevenção & controle , Periodontite/metabolismo , Inflamação , Dieta , Porphyromonas gingivalis
14.
J Am Chem Soc ; 145(31): 17075-17086, 2023 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-37490414

RESUMO

Complex I is a redox-driven proton pump that drives electron transport chains and powers oxidative phosphorylation across all domains of life. Yet, despite recently resolved structures from multiple organisms, it still remains unclear how the redox reactions in Complex I trigger proton pumping up to 200 Å away from the active site. Here, we show that the proton-coupled electron transfer reactions during quinone reduction drive long-range conformational changes of conserved loops and trans-membrane (TM) helices in the membrane domain of Complex I from Yarrowia lipolytica. We find that the conformational switching triggers a π → α transition in a TM helix (TM3ND6) and establishes a proton pathway between the quinone chamber and the antiporter-like subunits, responsible for proton pumping. Our large-scale (>20 µs) atomistic molecular dynamics (MD) simulations in combination with quantum/classical (QM/MM) free energy calculations show that the helix transition controls the barrier for proton transfer reactions by wetting transitions and electrostatic effects. The conformational switching is enabled by re-arrangements of ion pairs that propagate from the quinone binding site to the membrane domain via an extended network of conserved residues. We find that these redox-driven changes create a conserved coupling network within the Complex I superfamily, with point mutations leading to drastic activity changes and mitochondrial disorders. On a general level, our findings illustrate how catalysis controls large-scale protein conformational changes and enables ion transport across biological membranes.


Assuntos
Complexo I de Transporte de Elétrons , Prótons , Complexo I de Transporte de Elétrons/metabolismo , Oxirredução , Transporte de Elétrons , Quinonas , Bombas de Próton/metabolismo , Catálise
15.
J Am Chem Soc ; 145(10): 5696-5709, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36811855

RESUMO

Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO2, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions is the electron-bifurcating [FeFe]-hydrogenase HydABC that reduces low-potential ferredoxins (Fd) by oxidizing hydrogen gas (H2). By combining single-particle cryo-electron microscopy (cryoEM) under catalytic turnover conditions with site-directed mutagenesis experiments, functional studies, infrared spectroscopy, and molecular simulations, we show that HydABC from the acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui employ a single flavin mononucleotide (FMN) cofactor to establish electron transfer pathways to the NAD(P)+ and Fd reduction sites by a mechanism that is fundamentally different from classical flavin-based electron bifurcation enzymes. By modulation of the NAD(P)+ binding affinity via reduction of a nearby iron-sulfur cluster, HydABC switches between the exergonic NAD(P)+ reduction and endergonic Fd reduction modes. Our combined findings suggest that the conformational dynamics establish a redox-driven kinetic gate that prevents the backflow of the electrons from the Fd reduction branch toward the FMN site, providing a basis for understanding general mechanistic principles of electron-bifurcating hydrogenases.


Assuntos
Elétrons , Hidrogenase , Hidrogenase/química , NAD/metabolismo , Microscopia Crioeletrônica , Ferredoxinas/química , Oxirredução , Hidrogênio/química , Transporte de Elétrons
16.
BMC Microbiol ; 23(1): 325, 2023 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-37924042

RESUMO

BACKGROUND: This research evaluated the anti-Candida albicans effect of Mexican propolis from Chihuahua. Chemical composition of the ethanolic extract of propolis was determined by GC-MS, HPLC-DAD, and HPLC-MS. The presence of anthraquinone, aromatic acid, fatty acids, flavonoids, and carbohydrates was revealed. RESULTS: The anti-Candida activity of propolis was determined. The inhibitions halos were between 10.0 to 11.8 mm; 25% minimum inhibitory concentration (0.5 mg/ml) was fungistatic, and 50% minimum inhibitory concentration (1.0 mg/ml) was fungicidal. The effect of propolis on the capability of C. albicans to change its morphology was evaluated. 25% minimum inhibitory concentration inhibited to 50% of germ tube formation. Staining with calcofluor-white and propidium iodide was performed, showing that the propolis affected the integrity of the cell membrane. INT1 gene expression was evaluated by qRT-PCR. Propolis significantly inhibited the expression of the INT1 gene encodes an adhesin (Int1p). Chihuahua propolis extract inhibited the proliferation of Candida albicans, the development of the germ tube, and the synthesis of adhesin INT1. CONCLUSIONS: Given the properties demonstrated for Chihuahua propolis, we propose that it is a candidate to be considered as an ideal antifungal agent to help treat this infection since it would not have the toxic effects of conventional antifungals.


Assuntos
Candida albicans , Própole , Própole/farmacologia , Própole/química , Fatores de Virulência , México , Antifúngicos/farmacologia , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Proliferação de Células
17.
J Cardiovasc Electrophysiol ; 34(9): 1904-1913, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37482952

RESUMO

INTRODUCTION: The role that preprocedural factors have on atrioventricular synchrony (AVS) provided by leadless pacemakers requires investigation. METHODS AND RESULTS: We aimed to assess the correlation between mitral inflow echocardiographic parameters and p-wave morphology with the accelerometer A4 signal amplitude. We also sought to identify clinical and echocardiographic predictors of optimal ambulatory AVS (≥85% of cardiac cycles). Forty-three patients undergoing Micra AV implant from June 2020 to March 2023 were prospectively enrolled. Baseline echocardiogram and 12-lead resting ECG were performed. Device follow-up was scheduled at 24 h, 1, 3, and 6 months and yearly after the implant. Ambulatory AVS was studied with a 24 h Holter monitor performed at 3 months follow-up in 35 patients who remained in VDD mode. A4 signal amplitude at 1 month correlated to peak A wave velocity (r = .376; p = .024) at echocardiogram, but no relationship was found with peak A' wave velocity, E/A, or E'/A' ratio. P-wave amplitude in lead I and aVF correlated to A4 signal amplitude at 1- and 3-months follow-up, respectively. Median AVS during 24 h of daily activities was 85.6 ± 7.6% and remained stable up to 100 bpm. Twenty-three out of 35 patients (65.7%) reached optimal ambulatory AVS. There was no association between mitral inflow echocardiographic parameters and optimal AVS. Diabetes (OR: 0.05, 95% CI: 0.01-0.47; p = .009) and chronic obstructive pulmonary disease (COPD) (OR: 0.06, 95% CI: 0.01-0.63; p = .019) strongly predicted ambulatory AVS <85%. CONCLUSIONS: Diabetes and COPD should be considered when selecting candidates for Micra AV. Measurements of pulsed wave Doppler mitral inflow do not systematically reflect the behavior of the A4 signal amplitude.


Assuntos
Fibrilação Atrial , Marca-Passo Artificial , Humanos , Átrios do Coração , Ecocardiografia , Eletrocardiografia , Eletrocardiografia Ambulatorial , Estimulação Cardíaca Artificial/métodos
18.
J Exp Bot ; 74(19): 6131-6144, 2023 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-37279530

RESUMO

Plant growth and development depend on sufficient nutrient availability in soils. Agricultural soils are generally nitrogen (N) deficient, and thus soils need to be supplemented with fertilizers. Ammonium (NH4+) is a major inorganic N source. However, at high concentrations, NH4+ becomes a stressor that inhibits plant growth. The cause of NH4+ stress or toxicity is multifactorial, but the interaction of NH4+ with other nutrients is among the main determinants of plants' sensitivity towards high NH4+ supply. In addition, NH4+ uptake and assimilation provoke the acidification of the cell external medium (apoplast/rhizosphere), which has a clear impact on nutrient availability. This review summarizes current knowledge, at both the physiological and the molecular level, of the interaction of NH4+ nutrition with essential mineral elements that are absorbed as cations, both macronutrients (K+, Ca2+, Mg2+) and micronutrients (Fe2+/3+, Mn2+, Cu+/2+, Zn2+, Ni2+). We hypothesize that considering these nutritional interactions, and soil pH, when formulating fertilizers may be key in order to boost the use of NH4+-based fertilizers, which have less environmental impact compared with nitrate-based ones. In addition, we are convinced that better understanding of these interactions will help to identify novel targets with the potential to improve crop productivity.

19.
Haemophilia ; 29(3): 695-708, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36752329

RESUMO

INTRODUCTION: Although strength exercise is often prescribed for people with haemophilia (PWH), it remains unknown how exercise variables and pain thresholds are used to prescribe strength training in PWH. AIM: To analyse how strength exercise variables and pain thresholds have been used to prescribe strength training in PWH. METHODS: A systematic search was conducted in PubMed, Embase, Web of Science, CENTRAL and CINAHL databases from inception to 7 September 2022. Studies whose intervention included strengthening training in adults with haemophilia were included. Two independent reviewers were involved in study selection, data extraction and risk of bias assessment. RESULTS: Eighteen studies were included. The least reported variables among the studies were: prophylactic factor coverage (11.1%), pain threshold/tolerability (5.6%), intensity (50%), total or partial range of motion (27.8%), time under tension (27.8%), attentional focus modality (0%), therapist experience in haemophilia (33.3%) and adherence assessment (50%). In contrast, weekly frequency (94.4%), duration (weeks) (100%), number of sets/repetitions (88.9%), repetitions to failure/not to failure (77.8%), types of contraction (77.8%), rest duration (55.6%), progression (55.6%), supervision (77.8%), exercise equipment (72.2%) and adverse event record (77.8%) had a higher percentage of reported (>50% of studies). CONCLUSION: Future research on strength training for PWH should improve information on pain threshold and other important variables such as prophylactic factor coverage, intensity, range of motion, time under tension, attentional focus modality, therapist experience in haemophilia and adherence assessment. This could improve clinical practice and comparison of different protocols.


Assuntos
Hemofilia A , Treinamento Resistido , Adulto , Humanos , Exercício Físico , Terapia por Exercício/métodos , Hemofilia A/terapia , Limiar da Dor , Treinamento Resistido/métodos
20.
Nephrol Dial Transplant ; 38(1): 222-235, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-35404425

RESUMO

INTRODUCTION: Membranoproliferative glomerulonephritis (MPGN) represents a histologic pattern of glomerular injury that may be due to several aetiologies. Few studies have comprehensively analysed the recurrence of MPGN according to the current classification system. METHODS: We collected a multicentre, retrospective cohort of 220 kidney graft recipients with biopsy-proven native kidney disease due to MPGN between 1981 and 2021 in 11 hospitals. Demographic, clinical and histologic parameters of prognostic interest were collected. The main outcomes were time to kidney failure, time to recurrence of MPGN and disease remission after recurrence. RESULTS: The study group included 34 complement-mediated and 186 immune complex-mediated MPGN. A total of 81 patients (37%) reached kidney failure in a median follow-up of 79 months. The main predictors of this event were the development of rejection episodes and disease recurrence. In all, 54 patients (25%) had a disease recurrence in a median of 16 months after kidney transplantation. The incidence of recurrence was higher in patients with dysproteinaemia (67%) and complement-mediated MPGN (62%). In the multivariable model, complement-mediated MPGN emerged as a predictor of recurrence. A total of 33 patients reached kidney failure after recurrence. The main determinants of no remission were early time to recurrence (<15 months), estimated glomerular filtration rate <30 mL/min/1.73 m2 and serum albumin <3.5 g/dL at the time of recurrence. CONCLUSIONS: One-fourth of the patients with native kidney disease due to MPGN developed clinical recurrence in the allograft, especially in cases with complement-mediated disease or in those associated with dysproteinaemia. The kidney outcomes of disease recurrence with currently available therapies are heterogeneous and thus more effective and individualized therapies are needed.


Assuntos
Glomerulonefrite Membranoproliferativa , Glomerulonefrite , Falência Renal Crônica , Transplante de Rim , Humanos , Complexo Antígeno-Anticorpo , Proteínas do Sistema Complemento , Glomerulonefrite/complicações , Falência Renal Crônica/terapia , Recidiva , Estudos Retrospectivos
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