Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 293
Filtrar
1.
Nature ; 616(7958): 686-690, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37100940

RESUMO

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.

2.
Nature ; 621(7980): 711-715, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37758892

RESUMO

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1-4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.

3.
Environ Res ; 242: 117739, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38007076

RESUMO

In wastewater treatment plants (WWTPs), ammonia oxidation is primarily carried out by three types of ammonia oxidation microorganisms (AOMs): ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and comammox (CMX). Antibiotic resistance genes (ARGs), which pose an important public health concern, have been identified at every stage of wastewater treatment. However, few studies have focused on the impact of ARGs on ammonia removal performance. Therefore, our study sought to investigate the effect of the representative multidrug-resistant plasmid RP4 on the functional microorganisms involved in ammonia oxidation. Using an inhibitor-based method, we first evaluated the contributions of AOA, AOB, and CMX to ammonia oxidation in activated sludge, which were determined to be 13.7%, 41.1%, and 39.1%, respectively. The inhibitory effects of C2H2, C8H14, and 3,4-dimethylpyrazole phosphate (DMPP) were then validated by qPCR. After adding donor strains to the sludge, fluorescence in situ hybridization (FISH) imaging analysis demonstrated the co-localization of RP4 plasmids and all three AOMs, thus confirming the horizontal gene transfer (HGT) of the RP4 plasmid among these microorganisms. Significant inhibitory effects of the RP4 plasmid on the ammonia nitrogen consumption of AOA, AOB, and CMX were also observed, with inhibition rates of 39.7%, 36.2%, and 49.7%, respectively. Moreover, amoA expression in AOB and CMX was variably inhibited by the RP4 plasmid, whereas AOA amoA expression was not inhibited. These results demonstrate the adverse environmental effects of the RP4 plasmid and provide indirect evidence supporting plasmid-mediated conjugation transfer from bacteria to archaea.


Assuntos
Archaea , Betaproteobacteria , Archaea/genética , Archaea/metabolismo , Esgotos/microbiologia , Amônia , Nitrogênio/metabolismo , Desnitrificação , Hibridização in Situ Fluorescente , Oxirredução , Bactérias/genética , Bactérias/metabolismo , Plasmídeos/genética , Betaproteobacteria/genética , Betaproteobacteria/metabolismo , Antibacterianos , Filogenia , Microbiologia do Solo
4.
Biotechnol Lett ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39017763

RESUMO

Pentachlorophenol (PCP) was once used as a pesticide, germicide, and preservative due to its stable properties and resistance to degradation. This study aimed to design a biosensor for the quantitative and prompt detection of capable of PCP. A cell-free fluorescence biosensor was developed while employing NalC, an allosteric Transcription Factor responsive to PCP and In Vitro Transcription. By adding a DNA template and PCP and employing Electrophoretic Mobility Shift Assay while monitoring the dynamic fluorescence changes in RNA, this study offers evidence of NalC's potential applicability in sensor systems developed for the specific detection of PCP. The biosensor showed the capability for the quantitative detection of PCP, with a Limit of Detection (LOD) of 0.21 µM. Following the addition of Nucleic Acid Sequence-Based Amplification, the fluorescence intensity of RNA revealed an excellent linear relationship with the concentration of PCP, showing a correlation coefficient (R2) of 0.9595. The final LOD was determined to be 0.002 µM. This study has successfully translated the determination of PCP into a fluorescent RNA output, thereby presenting a novel approach for detecting PCP within environmental settings.

5.
Ecotoxicol Environ Saf ; 281: 116643, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38925033

RESUMO

Selenium (Se) pollution is mainly caused by anthropogenic activities, and the resulting biosecurity concerns have garnered significant attention in recent years. Using one-compartmental toxicokinetic (TK) modelling, this study explored the kinetic absorption, sub-tissue distribution, and elimination processes of the main Se species (selenate, Se(VI)) in the cultivated aerobic soil of the earthworm Eisenia fetida. The bio-accessibility of earthworm-derived Se was assessed using an in vitro simulated gastrointestinal digestion test to evaluate its potential trophic risk. The results demonstrated that Se accumulated in the pre-clitellum (PC) and total tissues (TT) of earthworms in a time- and dose-dependent manner. The highest Se levels in the PC, post-clitellum (PoC), and TT were 70.54, 57.93, and 64.26 mg/kg during the uptake phase, respectively. The kinetic Se contents in the earthworms PC and TT were consistent with the TK model but not with PoC. The earthworm TT exhibited a faster uptake (Kus = 0.83-1.02 mg/kg/day) and elimination rate of Se (Kee = 0.044-0.049 mg/kg/day), as well as a shorter half-life time (LT1/2 = 15.88-14.22 days) than PC at low soil Se levels (≤5 mg/kg). Conversely, the opposite trend was observed with higher Se concentrations (10 and 20 mg/kg). These results are likely attributable to the tissue specificity and concentration of the toxicant. Earthworms PC and TT exhibited a higher kinetic Se accumulation factor (BAFk) than steady-state BAF (BAFss), with values ranging from 8 to 24 and 3-13, respectively. Furthermore, the bio-accessibility of earthworm-derived Se to poultry ranged from 66.25 % to 84.35 %. As earthworms are at the bottom of the terrestrial food chain, the high bio-accessibility of earthworm-derived Se poses a potential risk to predators. This study offers data support and a theoretical foundation for understanding the biological footprint of soil Se and its toxicological impacts and ecological hazards.


Assuntos
Oligoquetos , Selênio , Poluentes do Solo , Toxicocinética , Oligoquetos/efeitos dos fármacos , Oligoquetos/metabolismo , Animais , Poluentes do Solo/toxicidade , Poluentes do Solo/farmacocinética , Selênio/toxicidade , Selênio/farmacocinética , Selênio/análise , Ácido Selênico/toxicidade , Ácido Selênico/farmacocinética , Distribuição Tecidual , Solo/química
6.
Ecotoxicol Environ Saf ; 276: 116288, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38581909

RESUMO

Cylindrospermopsin (CYN), a cyanobacterial toxin, has been detected in the global water environment. However, information concerning the potential environmental risk of CYN is limited, since the majority of previous studies have mainly focused on the adverse health effects of CYN through contaminated drinking water. The present study reported that CYN at environmentally relevant levels (0.1-100 µg/L) can significantly enhance the conjugative transfer of RP4 plasmid in Escherichia coli genera, wherein application of 10 µg/L of CYN led to maximum fold change of ∼6.5- fold at 16 h of exposure. Meanwhile, evaluation of underlying mechanisms revealed that environmental concentration of CYN exposure could increase oxidative stress in the bacterial cells, resulting in ROS overproduction. In turn, this led to an upregulation of antioxidant enzyme-related genes to avoid ROS attack. Further, inhibition of the synthesis of glutathione (GSH) was also detected, which led to the rapid depletion of GSH in cells and thus triggered the SOS response and promoted the conjugative transfer process. Increase in cell membrane permeability, upregulation of expression of genes related to pilus generation, ATP synthesis, and RP4 gene expression were also observed. These results highlight the potential impact on the spread of antimicrobial resistance in water environments.


Assuntos
Alcaloides , Toxinas Bacterianas , Toxinas de Cianobactérias , Escherichia coli , Glutationa , Plasmídeos , Uracila , Plasmídeos/genética , Glutationa/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Toxinas Bacterianas/toxicidade , Uracila/análogos & derivados , Uracila/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Conjugação Genética , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética
7.
Phytother Res ; 38(3): 1462-1477, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38246696

RESUMO

Reducing mitochondrial oxidative stress has become an important strategy to prevent neuronal death in ischemic stroke. Previous studies have shown that 20(R)-ginsenoside Rg3 can significantly improve behavioral abnormalities, reduce infarct size, and decrease the number of apoptotic neurons in cerebral ischemia/reperfusion injury rats. However, it remains unclear whether 20(R)-ginsenoside Rg3 can inhibit mitochondrial oxidative stress in ischemic stroke and the potential molecular mechanism. In this study, we found that 20(R)-ginsenoside Rg3 notably inhibited mitochondrial oxidative stress in middle cerebral artery occlusion/reperfusion (MCAO/R) rats and maintained the stability of mitochondrial structure and function. Treatment with 20(R)-ginsenoside Rg3 also decreased the levels of mitochondrial fission proteins (Drp1 and Fis1) and increased the levels of fusion proteins (Opa1, Mfn1, and Mfn2) in MCAO/R rats. Furthermore, we found that 20(R)-ginsenoside Rg3 promoted nuclear aggregation of nuclear factor erythroid2-related factor 2 (Nrf2) but did not affect Kelch-like ECH-associated protein-1 (Keap1), resulting in the downstream expression of antioxidants. In in vitro oxygen-glucose deprivation/reperfusion stroke models, the results of PC12 cells treated with 20(R)-ginsenoside Rg3 were consistent with animal experiments. After transfection with Nrf2 short interfering RNA (siRNA), the protective effect of 20(R)-ginsenoside Rg3 on PC12 cells was reversed. In conclusion, the inhibition of mitochondrial oxidative stress plays a vital position in the anti-cerebral ischemia-reperfusion injury of 20(R)-ginsenoside Rg3, and its neuroprotective mechanism is related to the activation of the nuclear factor erythroid2-related factor 2/heme oxygenase 1 signaling pathway.


Assuntos
Isquemia Encefálica , Ginsenosídeos , AVC Isquêmico , Fármacos Neuroprotetores , Traumatismo por Reperfusão , Ratos , Animais , Ratos Sprague-Dawley , Estresse Oxidativo , Fator 2 Relacionado a NF-E2/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fármacos Neuroprotetores/farmacologia , Transdução de Sinais , Traumatismo por Reperfusão/prevenção & controle , Infarto da Artéria Cerebral Média
8.
Chem Biodivers ; : e202400934, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898600

RESUMO

Ginseng saponins ( ginsenosides), bioactive compounds derived from ginseng, are widely used natural products with potent therapeutic properties in the management of various ailments, particularly tumors, cardiovascular and cerebrovascular diseases, and immune system disorders. Autophagy, a highly regulated and multistep process involving the breakdown of impaired organelles and macromolecules by autophagolysosomes and autophagy-related genes (ATGs), has gained increasing attention as a potential target for ginsenoside-mediated disease treatment. This review aims to provide a comprehensive overview of recent research advances in the understanding of autophagy-related signaling pathways and the role of ginsenoside-mediated autophagy regulation. By delving into the intricate autophagy signaling pathways underpinning the pharmacological properties of ginsenosides, we highlight their therapeutic potential in addressing various conditions. Our findings serve as a comprehensive reference for further investigation into the medicinal properties of ginseng or ginseng-related products.

9.
Angew Chem Int Ed Engl ; : e202409981, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39037730

RESUMO

Mediated electron transfer (MET) is fundamental to many biological functions, including cellular respiration, photosynthesis, and enzymatic catalysis. However, leveraging the MET process to enable the release of therapeutic gases has been largely unexplored. Herein, we report the bio-inspired activation of a series of UV-absorbing N-nitrosamide derivatives (NOA) under red light exposure, enabling the quantitative release of nitric oxide (NO) gasotransmitter via an MET process. The cornerstone of our design is the covalent linkage of a 2,4-dinitroaniline moiety, which acts as an electron mediator to the N-nitrosamide groups. This facilitates efficient electron transfer from the excited palladium(II) meso-tetraphenyltetrabenzoporphyrin (PdTPTBP) photocatalyst and the selective activation of NOA. Our approach has been validated with distinct photocatalysts and various N-nitrosamides, including those derived from carbamates, amides, and ureas. Notably, the modulation of the linker length between the electron mediator and N-nitrosamide groups serves as a regulatory mechanism for controlling NO release kinetics. Moreover, this biomimetic NO release platform demonstrates effective operation under both normoxic and hypoxic conditions, and it enables localized delivery of NO under physiological conditions, exhibiting significant anticancer efficacy within the phototherapeutic window and enhanced selectivity towards tumor cells.

10.
Mol Biol Evol ; 39(2)2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-34893856

RESUMO

Domestic sheep and their wild relatives harbor substantial genetic variants that can form the backbone of molecular breeding, but their genome landscapes remain understudied. Here, we present a comprehensive genome resource for wild ovine species, landraces and improved breeds of domestic sheep, comprising high-coverage (∼16.10×) whole genomes of 810 samples from 7 wild species and 158 diverse domestic populations. We detected, in total, ∼121.2 million single nucleotide polymorphisms, ∼61 million of which are novel. Some display significant (P < 0.001) differences in frequency between wild and domestic species, or are private to continent-wide or individual sheep populations. Retained or introgressed wild gene variants in domestic populations have contributed to local adaptation, such as the variation in the HBB associated with plateau adaptation. We identified novel and previously reported targets of selection on morphological and agronomic traits such as stature, horn, tail configuration, and wool fineness. We explored the genetic basis of wool fineness and unveiled a novel mutation (chr25: T7,068,586C) in the 3'-UTR of IRF2BP2 as plausible causal variant for fleece fiber diameter. We reconstructed prehistorical migrations from the Near Eastern domestication center to South-and-Southeast Asia and found two main waves of migrations across the Eurasian Steppe and the Iranian Plateau in the Early and Late Bronze Ages. Our findings refine our understanding of genome variation as shaped by continental migrations, introgression, adaptation, and selection of sheep.


Assuntos
Genoma , Carneiro Doméstico , Animais , Ásia , Europa (Continente) , Variação Genética , Irã (Geográfico) , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Ovinos/genética , Carneiro Doméstico/genética
11.
J Transl Med ; 21(1): 107, 2023 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-36765353

RESUMO

BACKGROUND: The incidence and mortality rate of gastrointestinal cancers are high worldwide. Increasing studies have illustrated that the occurrence, progression, metastasis and prognosis of cancers are intimately linked to the immune system. Mitochondria, as the main source of cellular energy, play an important role in maintaining the physiological function of immune cells. However, the relationship between mitochondrial function of immune cells and tumorigenesis has not yet been systematically investigated. METHODS: A total of 150 cases, including 60 healthy donors and 90 primary gastrointestinal cancer patients without anti-tumor treatments (30 with gastric cancer, 30 with liver cancer and 30 with colorectal cancer) were involved in our study. The oxidant/antioxidant and cytokine levels in plasma, the ROS level, mitochondrial function and apoptosis ratio of peripheral blood mononuclear cells (PBMCs) were evaluated. RESULTS: The imbalance between oxidant and antioxidant in plasma was discovered in the primary gastrointestinal cancer patients. The levels of cell reactive oxygen species (ROS) and mitochondrial ROS in PBMCs of primary gastrointestinal cancers were significantly increased compared with that in healthy donors. Meanwhile, the ATP content, the mtDNA copy number and the mitochondrial membrane potential (MMP) in PBMCs of patients with primary gastrointestinal cancers were lower than those in control group. The decreased MMP also occurred in immune cells of gastrointestinal cancers, including T cell, B cell, NK cell and monocyte. Furthermore, the PBMCs apoptosis ratio of primary gastrointestinal cancer patients was significantly higher than that of control group. Importantly, an increase of IL-2 and IL-6 and a decrease of IgG in plasma were found in the patients with primary gastrointestinal cancers. These changes of mitochondrial function in immune cells were consistent among primary gastrointestinal cancers without anti-tumor treatments, such as liver cancer, gastric cancer and colorectal cancer. CONCLUSION: Our study demonstrated that the imbalance of oxidation/antioxidation in primary gastrointestinal cancer patients without anti-tumor treatments results in excessive ROS. The oxidative stress was associated to the mitochondrial dysfunction, the apoptosis of immune cells and eventually the abnormal immune function in primary gastrointestinal cancers. The application of immune cell mitochondrial dysfunction into clinical evaluation is anticipated.


Assuntos
Neoplasias Colorretais , Neoplasias Gastrointestinais , Humanos , Espécies Reativas de Oxigênio/metabolismo , Leucócitos Mononucleares/metabolismo , Antioxidantes/metabolismo , Estresse Oxidativo , Mitocôndrias/metabolismo , Apoptose , Neoplasias Gastrointestinais/metabolismo , Neoplasias Gastrointestinais/patologia , Oxidantes/metabolismo , Neoplasias Colorretais/patologia
12.
J Chem Phys ; 159(11)2023 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-37712790

RESUMO

The collective density-density and hydrostatic pressure-pressure correlations of glass-forming liquids are spatiotemporally mapped out using molecular dynamics simulations. It is shown that the sharp rise of structural relaxation time below the Arrhenius temperature coincides with the emergence of slow, nonhydrodynamic collective dynamics on mesoscopic scales. The observed long-range, nonhydrodynamic mode is independent of wave numbers and closely coupled to the local structural dynamics. Below the Arrhenius temperature, it dominates the slow collective dynamics on length scales immediately beyond the first structural peak in contrast to the well-known behavior at high temperatures. These results highlight a key connection between the qualitative change in mesoscopic two-point collective dynamics and the dynamic crossover phenomenon.

13.
J Environ Manage ; 344: 118337, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37343473

RESUMO

This review aims to provide a comprehensive understanding of the potential of CMs-dominated DIET in the degradation of recalcitrant organic pollutants in AD. The review covers the mechanisms and efficiencies of recalcitrant organic pollutant degradation by CMs-dominated DIET, the comparison of degradation pathways between DIET and chemical treatment, recent insights on DIET-enhanced degradation, and the evaluation of the potential and future development of CMs-dominated DIET. The review emphasizes the importance of coupled syntrophic microorganisms, electron flux, and physicochemical properties of CMs in enhancing the degradation performance of AD. Additionally, it highlights the advantages of DIET-led syntrophic metabolism over traditional oxidation technologies in terms of environmental friendliness and efficiency. Finally, the review acknowledges the potential risks associated with introducing CMs into AD systems and provides guidance for waste treatment and energy recovery.


Assuntos
Elétrons , Metano , Anaerobiose , Transporte de Elétrons , Reatores Biológicos
14.
J Environ Manage ; 326(Pt B): 116732, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36402020

RESUMO

Direct interspecies electron transfer (DIET) stimulated by conductive materials (CMs) enables intercellular metabolic coupling that can address the unfavorable thermodynamical dilemma inherent in anaerobic digestion (AD). Although the DIET mechanism and stimulation have been extensively summarized, the methanogenesis contribution, characterization techniques, and downstream processes of CMs-led DIET in AD are surprisingly under-reviewed. Therefore, this review aimed to address these gaps. First, the contribution of CMs-led DIET to methanogenesis was re-evaluated by comparing the effect of various factors, including volatile fatty acids, free ammonia, and functional enzymes. It was revealed that AD systems are usually intricate and cannot allow the methanogenesis stimulation to be singularly attributed to the establishment of DIET. Additionally, considerable attention has been attached to the characterization of DIET occurrence, involving species identification, gene expression, electrical properties, cellular features, and syntrophic metabolism, suggesting the significance of accurate characterization methods for identifying the syntrophic metabolism interactions. Moreover, the type of CMs has a significant impact on AD downstream processes involving biogas purity, sludge dewaterability, and biosolids management. Finally, the central bottleneck consists in building a mathematical model of DIET to explain the mechanism of DIET in a deeper level from kinetics and thermodynamics.


Assuntos
Elétrons , Metano , Anaerobiose , Metano/metabolismo , Transporte de Elétrons , Esgotos , Tecnologia , Reatores Biológicos
15.
J Environ Manage ; 343: 118247, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37245313

RESUMO

The study developed a cost-effective integrated technology to treat swine wastewater at the pilot-scale small pigsty. The swine wastewater, which was separated rinse water after flowing through the slatted floor and the innovatively constructed liquid-liquid separate collection device, was subsequently pumped into an anaerobic baffled reactor (ABR) and then through zoning constructed wetlands (CWs) comprised of CW1, CW2, and CW3. The liquid-liquid separate collection device effectively reduced COD, NH4-N, and TN by 57.82%, 52.39%, and 50.95%, respectively. The CW1 and CW2 enhanced TN removal and nitrification, respectively, through rapid adsorption-bioregeneration of zeolite. Moreover, rice straws were used as solid carbon sources in CW3 to successfully promote denitrification at 16.0 g/(m3·d). The integrated technology (slatted floor-liquid liquid separate collection-ABR-CWs) reduced COD, NH4-N, and TN by 98.17%, 87.22%, and 87.88%, respectively, at approximately 10 °C. Microbial analysis results confirmed that the CWs exhibited apparent functional zoning, with denitrifiers dominating in CW3, nitrifiers dominating in the zeolite layers of CW1 and CW2, and denitrifiers dominating in the brick slag layers of CWs. This cost-effective integrated technology demonstrated significant potential for treating swine wastewater at low temperatures.


Assuntos
Águas Residuárias , Zeolitas , Suínos , Animais , Eliminação de Resíduos Líquidos/métodos , Desnitrificação , Áreas Alagadas , Nitrogênio/análise , Anaerobiose , Temperatura
16.
Angew Chem Int Ed Engl ; 62(52): e202314563, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-37964723

RESUMO

The development of dual gasotransmitter donors can not only provide robust tools to investigate their subtle interplay under pathophysiological conditions but also optimize therapeutic efficacy. While conventional strategies are heavily dependent on multicomponent donors, we herein report an ultrasound-responsive water-soluble copolymer (PSHF) capable of releasing carbon monoxide (CO) and hydrogen sulfide (H2 S) based on single-component sulfur-substituted 3-hydroxyflavone (SHF) derivatives. Interestingly, sulfur substitution can not only greatly improve the ultrasound sensitivity but also enable the co-release of CO/H2 S under mild ultrasound irradiation. The co-release of CO/H2 S gasotransmitters exerts a bactericidal effect against Staphylococcus aureus and demonstrates anti-inflammatory activity in lipopolysaccharide-challenged macrophages. Moreover, the excellent tissue penetration of ultrasound irradiation enables the local release of CO/H2 S in the joints of septic arthritis rats, exhibiting superior therapeutic efficacy without the need for any antibiotics.


Assuntos
Gasotransmissores , Sulfeto de Hidrogênio , Ratos , Animais , Monóxido de Carbono , Macrófagos , Enxofre
17.
Angew Chem Int Ed Engl ; 62(20): e202219153, 2023 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-36929516

RESUMO

The peroxynitrite anion (ONOO- ) is closely associated with many diseases and the creation of ONOO- donors is an essential means of understanding its pathophysiological functions. However, it is challenging to develop ONOO- donors due to the difficulties in simultaneously producing highly reactive and short-lived nitric oxide (NO) and superoxide anion (O2 ⋅- ). Here, we report a novel strategy for constructing ONOO- donors by combining near-infrared (NIR)-mediated type I photosensitization and photoredox catalysis. The key design using a Nile blue analogue that can serve as both a type I photosensitizer and a metal-free photocatalyst. Intriguingly, the formation of O2 ⋅- via type I photosensitization avoids oxygen interference and instead activates nitrobenzofurazan-based NO donors via oxygen-tolerant NIR photoredox catalysis. The simultaneous release of O2 ⋅- and NO leads to ONOO- release, showing both antibacterial and antibiofilm activities.


Assuntos
Oxigênio , Ácido Peroxinitroso , Superóxidos , Óxido Nítrico , Antibacterianos/farmacologia , Catálise
18.
BMC Microbiol ; 22(1): 36, 2022 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-35093006

RESUMO

The human gut is a reservoir of antibiotic resistance genes (ARGs). Even in the absence of antibiotics, ARGs are present in large quantities in faeces of adults, children and even newborns. However, where and when ARGs are acquired remains unclear, as does the types of ARGs acquired. Herein, we recruited 82 pairs of women and their caesarean section newborns. Conventional culture methods and quantitative PCR were employed to detect nine species and six ARG types in meconia, faeces from 3-day-old newborns, amniotic fluid, colostrum, and hospital ward air samples. Furthermore, ARG transfer was explored by tracking Staphylococcus epidermidis isolated from faeces of 3-day-old newborns, colostrum and ward air samples using multi-locus sequence typing (MLST). No ARGs or microorganisms were detected in meconia or amniotic fluid. One or more ARGs were detected in 90.2% of faeces from 3-day-old newborns, and the mecA gene exhibited the highest detection rate (45.1%). ARGs were detected in 85.4% of colostra consistent with ARGs in faeces from 3-day-old newborns. Some ARGs were detected in ward air, and might also be a source of ARGs in neonatal faeces. Isolation of S. epidermidis from neonatal faeces was consistent with antibiotic resistance and gene profiles for colostrum samples. Traceability analysis of S. epidermidis showed that ARGs in neonatal faeces mainly originated from colostrum, and partly from ward air. After birth, neonates born by caesarean section obtain a variety of ARGs mainly from colostrum, and partly from ward air.


Assuntos
Microbiologia do Ar , Bactérias/efeitos dos fármacos , Aleitamento Materno/estatística & dados numéricos , Cesárea/estatística & dados numéricos , Resistência Microbiana a Medicamentos/genética , Trato Gastrointestinal/efeitos dos fármacos , Genes Bacterianos/genética , Leite Humano , Adulto , Antibacterianos/farmacologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana , Fezes/microbiologia , Feminino , Trato Gastrointestinal/microbiologia , Hospitais , Humanos , Recém-Nascido , Masculino , Mães/estatística & dados numéricos , Tipagem de Sequências Multilocus , Gravidez
19.
Phys Rev Lett ; 129(5): 057801, 2022 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-35960564

RESUMO

We present a quantitative approach to the self-dynamics of polymers under steady flow by employing a set of complementary reference frames and extending the spherical harmonic expansion technique to dynamic density correlations. Application of this method to nonequilibrium molecular dynamics simulations of polymer melts reveals a number of universal features. For both unentangled and entangled melts, the center-of-mass motions in the flow frame are described by superdiffusive, anisotropic Gaussian distributions, whereas the isotropic component of monomer self-dynamics in the center-of-mass frame is strongly suppressed. Spatial correlation analysis shows that the heterogeneity of monomer self-dynamics increases significantly under flow.

20.
Arch Virol ; 167(2): 531-544, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35024965

RESUMO

Vibrio parahaemolyticus is a widely recognized pathogen that has caused numerous outbreaks and is prevalent in the marine environment. In this study, we investigated the characteristics of the novel V. parahaemolyticus strain BTXS2 and its associated phage, VB_VpP_BT-1011, isolated from the Bohai Coast (Tianjin, China). Strain BTXS2 is a short coryneform bacterium with a terminal flagellum and is able to utilize and metabolize a wide variety of organic matter because of its unique carbon source utilization and enzyme activity. It grows well in medium between pH 5.0 and 9.0 and salinities of simulated freshwater, estuary water, and seawater (NaCl 0.5%-3%). Multiple antibiotic resistance genes and virulence genes that endanger human health were found in the BTXS2 genome. Phage VB_VpP_BT-1011, which infects BTXS2, is a 40,065-bp double-stranded DNA virus of the family Myoviridae with a latent time of 30 min and burst size of 24 PFU/cell. Like its host, the phage tolerates a broad range of environmental conditions (salinity, 0-3% NaCl; pH 5.0-9.0; temperature, 4-37°C). A host range test showed that the phage only infected and inhibited isolate BTXS2. In summary, we investigated a novel V. parahaemolyticus host-phage pair and the antibacterial effect of the phage on V. parahaemolyticus, providing insights into marine microbial ecology and risks.


Assuntos
Bacteriófagos , Vibrio parahaemolyticus , Antibacterianos/farmacologia , Bacteriófagos/genética , Genoma Viral , Humanos , Myoviridae/genética , Vibrio parahaemolyticus/genética
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa