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Multienzyme-like nanozymes are nanomaterials with multiple enzyme-like activities and are the focus of nanozyme research owing to their ability to facilitate cascaded reactions, leverage synergistic effects, and exhibit environmentally responsive selectivity. However, multienzyme-like nanozymes exhibit varying enzyme-like activities under different conditions, making them difficult to precisely regulate according to the design requirements. Moreover, individual enzyme-like activity in a multienzyme-like activity may accelerate, compete, or antagonize each other, rendering the overall activity a complex interplay of these factors rather than a simple sum of single enzyme-like activity. A theoretically guided strategy is highly desired to accelerate the design of multienzyme-like nanozymes. Herein, nanozyme information was collected from 4159 publications to build a nanozyme database covering element type, element ratio, chemical valence, shape, pH, etc. Based on the clustering correlation coefficients of the nanozyme information, the material features in distinct nanozyme classifications were reorganized to generate compositional factors for multienzyme-like nanozymes. Moreover, advanced methods were developed, including the quantum mechanics/molecular mechanics method for analyzing the surface adsorption and binding energies of substrates, transition states, and products in the reaction pathways, along with machine learning algorithms to identify the optimal reaction pathway, to aid the evolutionary design of multienzyme-like nanozymes. This approach culminated in creating CuMnCo7O12, a highly active multienzyme-like nanozyme. This process is named the genetic-like evolutionary design of nanozymes because it resembles biological genetic evolution in nature and offers a feasible protocol and theoretical foundation for constructing multienzyme-like nanozymes.
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Nanoestructuras , Nanoestructuras/química , Evolución Biológica , Evolución Molecular , CatálisisRESUMEN
Keratitis, an inflammation of the cornea caused by bacterial or fungal infections, is one of the leading causes of severe visual disability and blindness. Keratitis treatment requires both the prevention of infection and the reduction of inflammation. However, owing to their limited therapeutic functions, in addition to the ocular barrier, existing conventional medications are characterized by poor efficacy and low bioavailability, requiring high dosages or frequent topical treatment, which represents a burden on patients and increases the risk of side effects. In this study, manganese oxide nanocluster-decorated graphdiyne nanosheets (MnOx/GDY) are developed as multienzyme-like nanozymes for the treatment of infectious keratitis and loaded into hyaluronic acid and polymethyl methacrylate-based ocular microneedles (MGMN). MGMN not only exhibits antimicrobial and anti-inflammatory effects owing to its multienzyme-like activities, including oxidase, peroxidase, catalase, and superoxide dismutase mimics but also crosses the ocular barrier and shows increased bioavailability via the microneedle system. Moreover, MGMN is demonstrated to eliminate pathogens, prevent biofilm formation, reduce inflammation, alleviate ocular hypoxia, and promote the repair of corneal epithelial damage in in vitro, ex vivo, and in vivo experiments, thus providing a better therapeutic effect than commercial ophthalmic voriconazole, with no obvious microbial resistance or cytotoxicity.
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Queratitis , Agujas , Queratitis/tratamiento farmacológico , Animales , Ratones , Enzimas/metabolismo , Biopelículas/efectos de los fármacos , Humanos , Óxidos , Compuestos de ManganesoRESUMEN
Low-dimensional networked organic-inorganic hybrid metal halide crystal has become an emerging hotspot material due to its opportunities and advantages in the development of white-light-emitting diodes. Therefore, its photoluminescence (PL) mechanism is important. Herein, we study the PL behavior of columniform TPP2MnBr4 crystals using multi-spectroscopy. The temperature-dependent PL data show that the PL of the TPP2MnBr4 crystal originates from the recombination of a self-trapping exciton. A polarization-dependent PL test suggests that the self-trapping exciton is anisotropic, which indicates that the distribution of self-trapping states is sensitive to the orientation of the crystal axis. Space-resolved PL spectroscopy shows that the anisotropy of PL gradually weakens along the orientation of the columniform crystal, which has a longer relaxation distance than traditional light-wave-guiding behavior. Thus, anisotropy of PL can exist before it disappears in the crystal. Our results elucidate the PL mechanism of low-dimensional networked organic-inorganic hybrid metal halide crystals and provide a foundation for advanced optical polarization devices based on them.
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Compuestos de Calcio , Dispositivos Ópticos , Óxidos , TemperaturaRESUMEN
Androgenetic alopecia (AGA) is a common form of hair loss, which is mainly caused by oxidative stress induced dysregulation of hair follicles (HF). Herein, a highly efficient manganese thiophosphite (MnPS3) based superoxide dismutase (SOD) mimic was discovered using machine learning (ML) tools. Remarkably, the IC50 of MnPS3 is 3.61 µg·mL-1, up to 12-fold lower than most reported SOD-like nanozymes. Moreover, a MnPS3 microneedle patch (MnMNP) was constructed to treat AGA that could diffuse into the deep skin where HFs exist and remove excess reactive oxygen species. Compared with the widely used minoxidil, MnMNP exhibits higher ability on hair regeneration, even at a reduced frequency of application. This study not only provides a general guideline for the accelerated discovery of SOD-like nanozymes by ML techniques, but also shows a great potential as a next generation approach for rational design of nanozymes.
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Alopecia , Minoxidil , Humanos , Alopecia/tratamiento farmacológico , Cabello , Superóxido Dismutasa , Aprendizaje AutomáticoRESUMEN
Graphdiyne (GDY) has been considered as an appealing electrode material for electrochemical sensing because of its alkyne-rich structure and high degrees of π-conjugation, which shows great affinity to heavy metal ions and pollutant molecules via d-π and π-π interactions. However, the low surface area and poor conductivity of bulk GDY limit its electrochemical performance. Herein, a two-dimensional ultrathin GDY/graphene (GDY/G) nanostructure was synthesized and used as an electrode material for electrochemical sensing. Graphene plays the role of an epitaxy template for few-layered GDY growth and conductive layers. The formed few-layered GDY with a high surface area possesses abundant affinity sites toward heavy metal ions (Cd2+, Pb2+) and toxic molecules, for example, nitrobenzene and 4-nitrophenol, via d-π and π-π interactions, respectively. Moreover, hemin as a key part of the enzyme catalytic motif was immobilized on GDY/G via π-π interactions. The artificial enzyme mimic hemin/GDY/G-modified electrode exhibited promising ascorbic acid and uric acid detection performance with excellent sensitivity and selectivity, a good linear range, and reproducibility. More importantly, real sample detection and the feasibility of this electrochemical sensor as a wearable biosensor were demonstrated.
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Contaminantes Ambientales , Grafito , Alquinos , Ácido Ascórbico , Cadmio , Grafito/química , Hemina/química , Iones , Plomo , Nitrobencenos , Reproducibilidad de los Resultados , Ácido ÚricoRESUMEN
Limited by the insufficient active sites and the interference from breath humidity, designing reliable gas sensing materials with high activity and moisture resistance remains a challenge to analyze human exhaled breath for the translational application of medical diagnostics. Herein, the dual sensing and cooperative diagnosis is achieved by utilizing metal-organic frameworks (MOFs) and its derivative. The Fe-MIL-101-NH2 serves as the quartz crystal microbalance humidity sensing layer, which exhibits high selectivity and rapid response time (16 s/15 s) to water vapor. Then, the Co2+ and Ni2+ cations are further co-doped into Fe-MIL-101-NH2 host to obtain the derived Co/Ni/Fe trimetallic oxides (CoNiFe-MOS-n). The chemiresistive CoNiFe-MOS-n sensor displays the high sensitivity (560) and good selectivity to acetone, together with a lower original resistance compared with Fe2 O3 and NiFe2 O4 . Moreover, as a proof-of-concept application, synergistic integration of Fe-MIL-101-NH2 and derived CoNiFe-MOS-n is carried out. The Fe-MIL-101-NH2 is applied as moisture sorbent materials, which realize a sensitivity compensation of CoNiFe-MOS-n sensors for the detection of acetone (biomarker gas of diabetes). The findings provide an insight for effective utilization of MOFs and the derived materials to achieve a trace gas detection in exhaled breath analysis.
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Estructuras Metalorgánicas , Materiales Inteligentes , Humanos , Estructuras Metalorgánicas/química , Óxidos , Acetona/química , Vapor , Cationes , BiomarcadoresRESUMEN
Metal peroxide nanoparticles designed to elevate the oxidative stress are considered a promising nanotherapeutics in biomedical applications, including chemotherapy, photodynamic therapy, and bacterial disinfection. However, their lack of specificity towards the therapeutic target can cause toxic side effects to healthy tissues. Here, silver peroxide nanoparticles (Ag2 O2 NPs) capable of controlled reactive oxygen species (ROS) release are synthesized. The release of bactericidal Ag+ ions and ROS is strictly regulated by external stimuli of ultrasound (US) and near-infrared (NIR) light. In vitro and in vivo investigations show that the Ag2 O2 NPs present enhanced antibacterial and antibiofilm capabilities with a killing efficiency >99.9999% in 10 min, significantly accelerate multi-drug resistant Staphylococcus aureus infected skin wound closure with excellent cytocompatibility and hemocompatibility. This work not only provides the first paradigm for fabricating silver peroxide nanoparticle but also introduces a highly efficient noninvasive and safe therapeutic modality for combating bacterial infectious diseases.
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Nanopartículas del Metal , Staphylococcus aureus Resistente a Meticilina , Nanopartículas , Infecciones Estafilocócicas , Antibacterianos/farmacología , Humanos , Peróxidos , Terapia Fototérmica , Plata , Infecciones Estafilocócicas/terapiaRESUMEN
Doping Cd element into perovskite materials is an effective strategy to improve the photoelectric property. However, the further discussion for carrier dynamic behavior in perovskites affected by Cd element remains not sufficient. In this research letter, based on steady and transient spectroscopy, it is found that adding Cd element into CsPbBr3 nanocrystals can enhance the activity of photo-generated carriers and accompany with the optimization of crystal structure. The former improves the carrier heating effect, which makes carrier keep high temperature for a long time and accelerate the bimolecular and the Auger recombination simultaneously. The latter can restrict the monomolecular recombination through passivating the defect states. Finally, they together improve the photoluminescence characteristics of the Cd doped CsPbBr3 nanocrystals and make them exhibit a huge potential in the fields of optoelectronics or photo-catalysis.
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The characteristics of a hot carrier distributed in the C excitonic state of the monolayer WS2 is investigated by exploiting the transient absorption (TA) spectroscopy. The hot carrier cooling lifetime gradually prolongs from 0.58 ps to 2.68 ps with the absorbed photon flux owing to the hot phonon bottleneck effect, as the excitation photon energy is 2.03 eV. Meanwhile, the normalized TA spectra shows that the spectral feature of hot carriers is different from that of normal carriers. Based on the modified Lennard-Jones model, the average distance among hot carriers can be estimated according to the peak shift of TA spectra and the diffusion velocity can also be calculated simultaneously. The hot carrier limits the diffusion of the photo-generated carrier at the initial several picoseconds. These results help people to elucidate the hot carrier dynamics in 2D TMDCs and give guidance on the designing and optimizing the TMDC-based electronic devices of high performance.
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Methane (CH4) gas sensors play an important role in industrial safety and detection of indoor gas quality. In general, metal oxide semiconductor sensing materials with nano-structure have high responses to the target gas. However, the sensor resistance is usually very high. Considering the practical application, it is vital to reduce base resistance and improve sensitivity for gas sensors. Herein, Pd-doped SnO2nanoparticles were prepared as the basis material by a simple sol-gel method. In order to adjust the resistance, the pentavalent metal element (Sb) was introduced via a simple doping route. As CH4sensing layers, the prepared SnO2-sensors doped with Pd and Sb exhibited the most obvious resistance reduction effect. Meantime, excellent sensing performances including high response, fast response/recovery time, excellent reproducibility and great stability were also obtained. In-depth research has shown that the ability to reduce resistance depends on the effective internal doping of cation with high valence. The enhanced sensing capability can be attributed to the 'synergistic effects' including catalytic effects of novel metals, increased oxygen vacancies and decreased band gap energy. This work can provide a new opportunity to design metal oxide sensing materials with low resistance and high sensitivity.
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From manufacture to disposal, the interaction of graphdiyne based nanomaterials with living organisms is inevitable and crucial. However, the cytotoxic properties of this novel carbon nanomaterial are rarely investigated, and the mechanisms behind their cytotoxicity are totally unknown. In this study, the antibacterial activity of graphdiyne (GDY) and graphdiyne oxide (GDYO) is reported. GDY is capable of inhibiting broad-spectrum bacterial growth while exerting moderate cytotoxicity on mammalian cells. In comparison, GDYO exhibits lower antibacterial activity than that of GDY. Then an alterable, synergetic antibacterial mechanism of GDY, involving wrapping bacterial membrane, membrane insertion and disruption, and reactive oxygen species generation is demonstrated, while the differential gene expression analysis indicates that GDY could only alter the bacterial metabolism slightly and the oxidative stress route may be a minor bactericidal factor. The investigation of the antibacterial behaviors of GDY based nanomaterials may provide useful guidelines for the future design and application of this novel molecular allotrope of carbon.
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Grafito , Nanoestructuras , Animales , Antibacterianos/farmacología , Óxidos/farmacologíaRESUMEN
Graphdiyne (GDY) as an emerging carbon nanomaterial has attracted increasing attention because of its uniformly distributed pores, highly π-conjugated, and tunable electronic properties. These excellent characteristics have been widely explored in the fields of energy storage and catalysts, yet there is no report on the development of sensors based on the outstanding optical property of GDY. In this paper, a new sensing mechanism is reported built upon the synergistic effect between inner filter effect and photoinduced electron transfer. We constructed a novel nanosensor based upon the newly-synthesized nanomaterial and demonstrated a sensitive and selective detection for both Fe3+ ion and ascorbic acid, enabling the measurements in real clinical samples. For the first time fluorescent graphdiyne oxide quantum dots (GDYO-QDs) were prepared using a facile ultrasonic protocol and they were characterized with a range of techniques, showing a strong blue-green emission with 14.6% quantum yield. The emission is quenched efficiently by Fe3+ and recovered by ascorbic acid (AA). We have fabricated an off/on fluorescent nanosensors based on this unique property. The nanosensors are able to detect Fe3+ as low as 95 nmol L-1 with a promising dynamic range from 0.25 to 200 µmol L-1. The LOD of AA was 2.5 µmol L-1, with range of 10-500 µmol L-1. It showed a promising capability to detect Fe3+ and AA in serum samples. Graphical abstract.
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Ácido Ascórbico/análisis , Compuestos Férricos/análisis , Grafito/química , Dispositivos Ópticos , Puntos Cuánticos/química , Ácido Ascórbico/sangre , Compuestos Férricos/sangre , Humanos , Límite de Detección , Microscopía de Fuerza Atómica , Microscopía Electrónica de Transmisión , Análisis Espectral/métodosRESUMEN
Plant development requires coordination among complex signaling networks to enhance the plant's adaptation to changing environments. DELLAs, transcription regulators originally identified as repressors of phytohormone gibberellin signaling, play a central role in integrating multiple signaling activities via direct protein interactions with key transcription factors. Here, we found that DELLA is mono-O-fucosylated by the novel O-fucosyltransferase SPINDLY (SPY) in Arabidopsis thaliana. O-fucosylation activates DELLA by promoting its interaction with key regulators in brassinosteroid- and light-signaling pathways, including BRASSINAZOLE-RESISTANT1 (BZR1), PHYTOCHROME-INTERACTING-FACTOR3 (PIF3) and PIF4. Moreover, spy mutants displayed elevated responses to gibberellin and brassinosteroid, and increased expression of common target genes of DELLAs, BZR1 and PIFs. Our study revealed that SPY-dependent protein O-fucosylation plays a key role in regulating plant development. This finding may have broader importance because SPY orthologs are conserved in prokaryotes and eukaryotes, thus suggesting that intracellular O-fucosylation may regulate a wide range of biological processes in diverse organisms.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fucosiltransferasas/metabolismo , Proteínas Represoras/metabolismo , Arabidopsis/enzimología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Fucosiltransferasas/genética , Proteínas Represoras/genéticaRESUMEN
Etched PtCu nanowires (NWs) were synthesized by a hydrothermal reaction and chemical etching process. The NWs are shown to be viable peroxidase (POx) mimics capable of catalyzing the oxidation of the substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to form a blue-green coloration. The mechanism of catalysis was investigated and the results demonstrated that H2O2 is decomposed to form hydroxyl radicals which oxidize TMB in the presence of the NWs. Under optimized conditions, a steady-state kinetic analysis revealed that the NWs possess a stronger affinity for H2O2 and TMB compared to the enzyme horseradish POx. Based on the high POx-like activity, a colorimetric assay for H2O2 was established. Absorbance at 652 nm increases linearly in the 0.1-300 µM H2O2 concentration range, and the detection limit is 0.06 µM (at S/N = 3). The assay was successfully applied to the determination of H2O2 in (spiked) milk and contact lens solution. Furthermore, a highly sensitive test strip was designed which represents a low cost and fast alternative for the visual determination of H2O2. Graphical Abstract Schematic presentation of the colorimetric detection of H2O2. PtCu nanowires (PtCu NWs) can catalyze 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by H2O2 to produce blue-green oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB). Based on the color change, test strips were designed for H2O2 detection.
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BACKGROUND/AIMS: In recent years, microRNA-495 (miR-495) has been reported to be a tumor-suppressor miR that is down-modulated in cancers. However, its potential mechanism remains unknown. Therefore, this study aimed to demonstrate the role of miR-495 in cardiac microvascular endothelial cell (CMEC) injury and inflammatory reaction by mediating the pyrin domain-containing 3 (NLRP3) inflammasome signaling pathway. METHODS: Overall, 40 mice were assigned into myocardial ischemia/reperfusion injury (MIR) and sham groups. After model establishment, the levels of troponin T (TnT), troponin I (TnI), N-terminal pro-B-type natriuretic peptide (NT-proBNP), creatine kinase isoenzyme MB (CK-MB), myoglobin (MYO), tumor necrosis factor-alpha (TNF-α), and interleukin 1beta (IL-1ß) were detected by Enzyme-Linked Immunosorbent Assay (ELISA). Apoptosis was evaluated using Terminal deoxy (d)-UTP nick end labeling (TUNEL) staining, the level of NLRP3 protein was determined by immunohistochemical assay, and miR-495 was detected by in situ hybridization (ISH). The infarct size was determined using 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. The expression of miR-495 and the mRNA and protein levels of NLRP3, TNF-α, IL-1ß, IL-18 and caspase-1 were evaluated by RT-qPCR and western blot analysis. After transfection, the cells were treated with a miR-495 mimic, a miR-495 inhibitor, or siNLRP3. Cell proliferation was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and cell cycle and apoptosis by flow cytometry. RESULTS: Mice with myocardial I/R injury had elevated levels of TnT, TnI, NT-proBNP, CK-MB, MYO, TNF-α and IL-1ß; enhanced cell apoptosis; increased expression of NLRP3, TNF-α, IL-1ß, IL-18 and caspase-1; and decreased miR-495 expression. MiR-495 was confirmed to target NLRP3. Moreover, miR-495 reduced the mRNA and protein levels of NLRP3, TNF-α, IL-1ß, IL-18 and caspase-1, inhibited cell apoptosis and decreased cells at the G0/G1 phase while improving cell proliferation and increasing cells at the S phase. However, the effects of NLRP4 were proved to be reciprocal. CONCLUSION: In conclusion, the current study indicated that miR-495 improved CMEC injury and inflammation by suppressing the NLRP3 inflammasome signaling pathway.
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Inflamasomas/metabolismo , MicroARNs/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Transducción de Señal , Regiones no Traducidas 3' , Animales , Antagomirs/metabolismo , Apoptosis , Caspasa 1/genética , Caspasa 1/metabolismo , Modelos Animales de Enfermedad , Células Endoteliales/citología , Células Endoteliales/metabolismo , Puntos de Control de la Fase G1 del Ciclo Celular , Interleucina-18/genética , Interleucina-18/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Ratones , Ratones Endogámicos C57BL , MicroARNs/antagonistas & inhibidores , MicroARNs/genética , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Miocardio/metabolismo , Miocardio/patología , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Interferencia de ARN , ARN Interferente Pequeño/metabolismoRESUMEN
Imidazo-[1, 2-a]pyrazine 1 is a potent inhibitor of Aurora A and B kinase in vitro and is effective in in vivo tumor models, but has poor oral bioavailbility and is unsuitable for oral dosing. We describe herein our effort to improve oral exposure in this class, resulting ultimately in the identification of a potent Aurora inhibitor 16, which exhibited good drug exposure levels across species upon oral dosing, and showed excellent in vivo efficacy in a mouse xenograft tumor model when dosed orally.
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Antineoplásicos/uso terapéutico , Aurora Quinasa A/antagonistas & inhibidores , Aurora Quinasa B/antagonistas & inhibidores , Imidazoles/uso terapéutico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirazinas/uso terapéutico , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/síntesis química , Antineoplásicos/farmacocinética , Perros , Células HCT116 , Haplorrinos , Histonas/metabolismo , Humanos , Imidazoles/administración & dosificación , Imidazoles/síntesis química , Imidazoles/farmacocinética , Ratones , Fosforilación , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Pirazinas/administración & dosificación , Pirazinas/síntesis química , Pirazinas/farmacocinética , Ratas , Estereoisomerismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The photoluminescence (PL) characteristics of CdSe quantum dots (QDs) infiltrated into inverse opal SiO2 photonic crystals (PCs) are systemically studied. The special porous structure of inverse opal PCs enhanced the thermal exchange rate between the CdSe QDs and their surrounding environment. Finally, inverse opal SiO2 PCs suppressed the nonlinear PL enhancement of CdSe QDs in PCs excited by a continuum laser and effectively modulated the PL characteristics of CdSe QDs in PCs at high temperatures in comparison with that of CdSe QDs out of PCs. The final results are of benefit in further understanding the role of inverse opal PCs on the PL characteristics of QDs.
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Compuestos de Cadmio/química , Luminiscencia , Fotones , Puntos Cuánticos , Compuestos de Selenio/química , Semiconductores , Dióxido de Silicio/química , Temperatura , Cristalización , Óptica y FotónicaRESUMEN
Ground-level ozone (O3) is a primary air pollutant with potential adverse impacts on human health and ecosystems. Aiming to detect O3 concentration and develop efficient O3 sensing materials, sensing behavior of heterogenous cation (Fe3+, Sn4+ and Sb5+) doped In2O3 nanostructures was investigated. The incorporation of these cations modulated the electronic structure of semiconductor oxides, affecting the density of chemisorbed oxygen species and reactive sites. From O3 sensing results, Fe3+ doped In2O3 based sensors featuring saturated resistance curves in O3 gas, demonstrated fast sensing speed and qualified detection threshold (20 ppb). In contrast, Sn4+ and Sb5+ doped counterparts exhibited non-saturated sensing curves, resulting in slower response/recovery speed. As a proof-of-concept, these optimized sensors were integrated as the sensor array. Coupled to the image recognition technique, this sensor array could successfully discriminate O3 and NOx. That is, through the tailored combination of material modulation and sensor array, this study paves a novel approach for highly sensitive and selective O3 detection.
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Penicillin-binding proteins (PBPs) include transpeptidases, carboxypeptidases, and endopeptidases for biosynthesis of peptidoglycans in the cell wall to maintain bacterial morphology and survival in the environment. Streptococcus pneumoniae expresses six PBPs, but their enzymatic kinetic characteristics and inhibitory effects on different ß-lactam antibiotics remain poorly understood. In this study, all the six recombinant PBPs of S. pneumoniae displayed transpeptidase activity with different substrate affinities (Km = 1.56-9.11 mM) in a concentration-dependent manner, and rPBP3 showed a greater catalytic efficiency (Kcat = 2.38 s-1) than the other rPBPs (Kcat = 3.20-7.49 × 10-2 s-1). However, only rPBP3 was identified as a carboxypeptidase (Km = 8.57 mM and Kcat = 2.57 s-1). None of the rPBPs exhibited endopeptidase activity. Penicillin and cefotaxime inhibited the transpeptidase and carboxypeptidase activity of all the rPBPs but imipenem did not inhibited the enzymatic activities of rPBP3. Except for the lack of binding of imipenem to rPBP3, penicillin, cefotaxime, and imipenem bound to all the other rPBPs (KD = 3.71-9.35 × 10-4 M). Sublethal concentrations of penicillin, cefotaxime, and imipenem induced a decrease of pneumococcal pbps-mRNA levels (p < 0.05). These results indicated that all six PBPs of S. pneumoniae are transpeptidases, while only PBP3 is a carboxypeptidase. Imipenem has no inhibitory effect on pneumococcal PBP3. The pneumococcal genes for encoding endopeptidases remain to be determined.
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Peptidil Transferasas , Proteínas de Unión a las Penicilinas/genética , Proteínas de Unión a las Penicilinas/metabolismo , Proteínas de Unión a las Penicilinas/farmacología , Peptidil Transferasas/genética , Peptidil Transferasas/farmacología , Streptococcus pneumoniae/metabolismo , Antibacterianos/farmacología , Peptidoglicano/farmacología , Proteínas Bacterianas/metabolismo , Penicilinas/metabolismo , Penicilinas/farmacología , Imipenem/farmacología , Cefotaxima , Monobactamas/farmacología , Carboxipeptidasas , Antibióticos Betalactámicos , Endopeptidasas/farmacologíaRESUMEN
Liver cancer represents a grave hepatic condition and constitutes a significant global health concern. Surgical resection remains the principal therapeutic modality for liver cancer. Nevertheless, perioperative malnutrition exerts a notable impact on patients with liver cancer, emerging as an independent risk factor for disease mortality and adverse outcomes. Hence, precise nutritional diagnosis and timely nutritional support hold the potential to enhance therapeutic efficacy and quality of life for liver cancer patients. This study represents a meticulous foray into the literature, extracting data from PubMed, Web of Science, and EMBASE databases, with a focus on the past 5 years. It scrutinizes the impact of malnutrition on patients undergoing liver cancer surgery, the etiological underpinnings of malnutrition within this patient cohort, the critical assessment of perioperative nutritional status, and the strategic approaches to nutritional support. Utilizing rigorous inclusion and exclusion criteria, the amassed scholarly works are meticulously synthesized, methodically organized, and categorically elaborated upon. Ultimately, the authors propose the incorporation of a multidisciplinary nutrition management team during the perioperative period, comprising nutritionists, pharmacists, physicians, nurses, psychologists, and rehabilitation therapists, among other specialized professionals. Together, they collaborate to devise and implement personalized nutritional support plans, monitor patients' nutritional status, and make necessary adjustments as required. Through comprehensive management and intervention, improvements in the nutritional status of liver cancer patients can be achieved, thereby enhancing surgical success rates and facilitating postoperative recovery. It is believed that this manuscript will offer valuable insights to advance the nutritional management during the perioperative phase of liver cancer, aiding in ameliorating patients' nutritional status and treatment outcomes.