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1.
Nanoscale ; 13(29): 12546-12552, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477613

RESUMO

A metal-organic framework (MOF) material was prepared from 2-aminoterephthalic acid and aluminum chloride with a solvothermal synthesis protocol. The as-prepared MOF material named NH2-MIL-53(Al) emitted a very intensive fluorescent (FL) signal after it was hydrolyzed in alkaline solution for releasing numerous FL ligands NH2-H2BDC. Thus it can be considered as a sensitive FL probe for studying biorecognition events. In this proof-of-principle work, a double-site recognition method was established to quantify Staphylococcus aureus (S. aureus) relying on the alkaline hydrolysis property of the MOF material. In particular, magnetic beads (MBs) modified with pig IgG were adopted for binding S. aureus based on the strong affinity between pig IgG and protein A on the bacterial surface. Meanwhile, MOF NH2-MIL-53(Al)-tagged teicoplanin (TEI) was adopted for tracing the target bacteria. By hydrolyzing the MOF material bound on the MBs to trigger the FL signal, S. aureus can be quantified with a dynamic range of 3.3 × 103-3.3 × 107 CFU mL-1 and a detection limit of 5.3 × 102 CFU mL-1 (3σ). The method can exclude efficiently the interference from other common bacteria. It has been applied to quantify S. aureus in saliva, pomegranate green tea, glucose injection and milk samples with satisfactory results, verifying the application potential for analyzing various types of real samples contaminated with S. aureus.


Assuntos
Estruturas Metalorgânicas , Infecções Estafilocócicas , Animais , Corantes Fluorescentes , Hidrólise , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus , Suínos
2.
Anal Chim Acta ; 1180: 338855, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34538321

RESUMO

As one of the top three opportunistic pathogens, Pseudomonas aeruginosa (P. aeruginosa) has long accounted for hospital-acquired infections with high risk of death. In this work, a fluorescent method based on a dual-site recognition mode was developed for rapid assay of P. aeruginosa. Employing its strong binding capability towards lipid A on the outer membrane of Gram-negative bacteria, polymyxin B acted as one recognition element for P. aeruginosa. To overcome the poor binding specificity of polymyxin B, a recombinant bacteriophage tail fiber protein was expressed and employed as a species-specific recognition element for the target pathogen. Thus a dual-site recognition mode was developed for specific assay of P. aeruginosa species by using fluorescein isothiocyanate as a fluorescent probe. The target pathogen can be assayed within a broad dynamic range from 2.0 × 103 CFU mL-1 to 2.0 × 107 CFU mL-1. Due to the ideal specificity of tail fiber protein, the method is capable of excluding the interference from other Gram-negative bacteria and all Gram-positive bacteria. It has been employed for assaying P. aeruginosa in various types of sample matrixes inclusive of lake water, physiological saline injection, human urine and milk. The acceptable assay results demonstrate its promising prospect for practical application in various areas such as environmental hygiene, medical diagnosis, as well as drug and food safety.


Assuntos
Bacteriófagos , Polimixina B , Pseudomonas aeruginosa/isolamento & purificação , Antibacterianos , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Testes de Sensibilidade Microbiana
3.
Neurochem Res ; 46(11): 3075-3084, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34374900

RESUMO

3-n-Butylphthalide (NBP), an extract from seeds of Apium graveolens Linn. (Chinese celery), has been demonstrated to have antidepressant effects in suspension chronic-stressed rats by our group. The purpose of this study was to investigate the possible involvement of brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the antidepressant mechanism of NBP. Chronic unpredictable mild stress (CUMS) was applied for 6 weeks to induced a depressive-like behavior, characterized by decreased locomotor activity, sucrose preference and the NE, DA and 5-HT levels in cortex. Oral treatment with NBP (30 or 100 mg/kg, p.o.), similarly to fluoxetine (2 mg/kg, p.o.), can prevention of these alterations. The NBP (30 or 100 mg/kg, p.o.) reversed the decrease in the BDNF, p-ERK, mTOR and synapsin-1 protein levels in rat cortex caused by CUMS. And rapamycin, an mTOR inhibitor, completely inhibited the antidepressant-like activity of NBP in vivo. In conclusion, these findings indicate that NBP treatment attenuated the depression-like behaviors through the modulation of serotonergic system and BDNF-ERK-mTOR signaling in rat.

4.
Front Cell Infect Microbiol ; 11: 668430, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33937105

RESUMO

As a potential antibacterial agent, endolysin can directly lyse Gram-positive bacteria from the outside and does not lead to drug resistance. Considering that XN108 is the first reported methicillin-resistant Staphylococcus aureus (MRSA) strain in mainland China with a vancomycin MIC that exceeds 8 µg mL-1, we conducted a systematic study on its phage-encoded endolysin LysP108. Standard plate counting method revealed that LysP108 could lyse S. aureus and Pseudomonas aeruginosa with damaged outer membrane, resulting in a significant reduction in the number of live bacteria. Scanning electron microscopy results showed that S. aureus cells could be lysed directly from the outside by LysP108. Live/dead bacteria staining results indicated that LysP108 possessed strong bactericidal ability, with an anti-bacterial rate of approximately 90%. Crystal violet staining results implied that LysP108 could also inhibit and destroy bacterial biofilms. In vivo animal experiments suggested that the area of subcutaneous abscess of mice infected with MRSA was significantly reduced after the combined injection of LysP108 and vancomycin in comparison with monotherapy. The synergistic antibacterial effects of LysP108 and vancomycin were confirmed. Therefore, the present data strongly support the idea that endolysin LysP108 exhibits promising antibacterial potential to be used as a candidate for the treatment of infections caused by MRSA.


Assuntos
Bacteriófagos , Staphylococcus aureus Resistente à Meticilina , Animais , Antibacterianos , China , Endopeptidases , Camundongos , Testes de Sensibilidade Microbiana , Staphylococcus aureus
5.
Biosens Bioelectron ; 182: 113189, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33799025

RESUMO

As one of the most common and noticeable superbugs, methicillin-resistant Staphylococcus aureus (MRSA) has long been a major threat to public health. To meet the demand for effective diagnosis of MRSA-induced infection, it is urgent to establish rapid assay method for this type of pathogen. In this study, an aqueous soluble cellular wall-binding domain (CWBD) protein from bacteriophage P108 was obtained with a recombinant expression technique. It can act as a wide-spectrum binding agent for all MRSA strains and exclude the interference from methicillin-susceptible strains of Staphylococcus aureus and other species of bacteria. To establish a lateral flow assay (LFA) method for MRSA, CWBD-coupled time-resolved fluorescent microspheres (FMs) were used as signal probes for tracing MRSA, and a nitrocellulose membrane immobilized with porcine IgG was used to capture MRSA. With the LFA based on sandwich format, MRSA can be assayed within 10 min with a broad linear range of 6.6 × 102-6.6 × 107 CFU/mL. Its application potential has been demonstrated by assaying different types of bacteria-contaminated real samples. The results suggest that the LFA strip using recombinant CWBD as the recognition agent provides a rapid, portable, cost-effective approach for point-of-care testing of MRSA.


Assuntos
Bacteriófagos , Técnicas Biossensoriais , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Antibacterianos/uso terapêutico , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus , Suínos
6.
Talanta ; 227: 122203, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33714473

RESUMO

Immunochromatographic test strip (ITS) for point-of-care testing (POCT) has attracted prominent attention due to the advantages including rapid response, low cost and good portability. Here, we developed a sensitive ITS for detecting aflatoxin B1 (AFB1) by using dendritic platinum nanoparticles (DPNs) as novel pressure/colorimetric dual-readout probes. DPNs-labeled antibody of AFB1 were used as the signal tracer of the immunochromatographic process. After 10-min competitive immunoreaction, black color appeared on the test line of ITS due to the accumulation of DPNs, which was observed visually as a colorimetric readout for qualitation purpose. Furthermore, DPNs with peroxidase-like activity caused decomposition of hydrogen peroxide aqueous solution to produce pressure change signal in vials, which was detected by a hand-held pressure meter for quantitation purpose. With the pressure readout mode, the detection range was 0.05-10 ng mL-1, and the detection limit was 0.03 ng mL-1 (S/N = 3) for AFB1. The proposed ITS was successfully utilized for detecting AFB1 in herbal medicine samples, and the acceptable recoveries of 93.77-114.09% indicated the reliability for real sample detection. It provides a new avenue for POCT with great application potential in various area including drug and food quality control, pollutants monitoring as well as medical diagnosis.


Assuntos
Aflatoxina B1 , Nanopartículas Metálicas , Aflatoxina B1/análise , Colorimetria , Limite de Detecção , Platina , Testes Imediatos , Reprodutibilidade dos Testes
7.
Anal Chim Acta ; 1145: 17-25, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33453875

RESUMO

Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, ranks one of the most dangerous pathogens for its large deaths toll. Due to its characteristic extremely slow growth, the conventional culture-based protocol cannot meet the requirement for the efficient diagnosis of M. tuberculosis-induced tuberculosis. With our previously isolated mycobacteriophage SWU1, we tried to develop a mycobacteriophage-based protocol for detecting Mycobacterium genus. In this work, Mycobacterium smegmatis (M. smegmatis) was used as a model due to its similar physiological features as pathogenic M. tuberculosis, much faster growth and nonpathogenic property. Mycobacteriophage SWU1-functionalized magnetic particles (SWU1-MPs) were used as highly efficient separation carriers for the viable host M. smegmatis. After a replication cycle of approximate 60 min, the cells of M. smegmatis were disrupted by the progeny mycobacteriophages to release intracellular adenosine triphosphate (ATP). The bioluminescent (BL) signal of released ATP was collected to quantitate the amount of M. smegmatis. For the developed protocol, the detection range is 5.0 × 102 to 5.0 × 105 CFU mL-1, and the detection limit is 3.8 × 102 CFU mL-1 (S/N = 3). Furthermore, the protocol can exclude the potential interference of 3 non-pathogenic mycobacteria and 6 other bacterial species. It has been successfully applied to quantitate M. smegmatis in human urine, human saliva, and human serum. The results demonstrate its application potential for a simple, fast, and specific diagnosis of M. tuberculosis infection.


Assuntos
Micobacteriófagos , Mycobacterium tuberculosis , Tuberculose , Humanos , Fenômenos Magnéticos , Mycobacterium smegmatis
8.
Anal Chim Acta ; 1148: 238174, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33516386

RESUMO

Novel cobalt-based metal-organic frameworks (Co MOFs) were synthesized by a facile "controlled synthesis" strategy. The MOFs displayed superior catalytic performance on the chemiluminescent (CL) reaction between N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and H2O2. UV-vis absorption, CL spectrum, ESR, and radical scavenger experiments were conducted for clarifying the catalytic mechanism of Co MOFs. All results revealed that Co MOFs can accelerate decomposition of H2O2 and production of OH•, O2•-as well as 1O2 radicals. The rapid reaction between these reactive oxygen species and ABEI resulted in the generation of ABEI-ox∗. The excited-state oxidation product emitted a very intensive CL signal with a maximal emission wavelength of 430 nm as it returned to the ground state. To explore their application potential in CL assay, Co MOFs were used as powerful CL reaction catalyst for establishing a very sensitive method for immunoassay of aflatoxin B1. The detection range was 0.05-60 ng mL-1, and the limit of detection was 4.3 pg mL-1. The result for detecting herbal medicine samples demonstrates the acceptable reliability of the Co MOFs-based CL immunoassay. The proof-of-principle work verifies the application potential of Co MOFs on boosting intensive CL signal, and meets the demand for high sensitivity in various bioassay fields.


Assuntos
Estruturas Metalorgânicas , Cobalto , Peróxido de Hidrogênio , Medições Luminescentes , Luminol/análogos & derivados , Reprodutibilidade dos Testes
9.
Chemistry ; 26(34): 7583-7588, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32428322

RESUMO

Co single-atom catalysts (SACs) with good aqueous solubility and abundant labelling functional groups were prepared in Co/Fe bimetallic metal-organic frameworks by a facile solvothermal method without high-temperature calcination. In contrast to traditional chemiluminescence (CL) catalysts, Co SACs accelerated decomposition of H2 O2 to produce a large amount of singlet oxygen (1 O2 ) rather than superoxide (O2 .- ) and hydroxyl radical (OH. ). They were found to dramatically enhance the CL emission of the luminol-H2 O2 reaction by 1349 times, and, therefore, were employed as very sensitive signal probes for conducting CL immunoassay of cardiac troponin I. The detection limit of the target analyte was as low as 3.3 pg mL-1 . It is the first time that employment of SACs for boosting CL reactions has been validated. The Co SACs can also be employed to trace other biorecognition events with high sensitivity.


Assuntos
Radical Hidroxila/química , Luminol/química , Oxigênio Singlete/química , Catálise , Limite de Detecção , Luminescência , Medições Luminescentes/métodos , Estruturas Metalorgânicas , Superóxidos
10.
Talanta ; 211: 120728, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32070624

RESUMO

Based on the specific affinity behavior of teicoplanin towards Gram-positive (G+) bacteria, teicoplanin-coated magnetic particles were employed to separate G+ bacteria. Moreover, intracellular catalase released by catalase-positive bacteria led to catalyzed hydrolysis of H2O2 and inhibition of chemiluminescent signal of luminol-H2O2 system. By combining the separation capability of teicoplanin-coated magnetic particles and the inhibition of luminol chemiluminescence by catalase, a facile method was proposed for quantifying catalase-positive G+ bacteria. In this proof-of-principle work, Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus were adopted as model bacteria to evaluate its quantification performance. The three bacteria were quantified within the dynamic ranges of 5.0 × 102-5.0 × 107 CFU mL-1, 4.0 × 102-4.0 × 107 CFU mL-1 and 2.0 × 102-2.0 × 107 CFU mL-1, with detection limits of 156 CFU mL-1, 86 CFU mL-1 and 44 CFU mL-1, respectively. Gram-negative bacteria and catalase-negative G+ bacteria both displayed minor interference. The results for quantifying bacteria in milk, human urine and physiological saline samples demonstrated its reliability for real application. It provided a promising technique tool for food safety, medical diagnosis as well as drug quality control.


Assuntos
Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Magnetismo , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus/isolamento & purificação , Teicoplanina/química , Animais , Humanos , Hidrólise , Leite/microbiologia , Solução Salina/química , Infecções Estafilocócicas/microbiologia , Urinálise
11.
Anal Chem ; 92(4): 3340-3345, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-31967786

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) has been well-recognized as one of the most common multiresistant bacteria threatening human health. Broad-spectrum recognition of multiple MRSA strains can meet the urgent demands for efficient diagnosis and subsequent decision of relevant treatment of MRSA-induced infections. Here, recombinant cell-binding domain (CBD) and green fluorescent protein-fused CBD of MRSA bacteriophage were expressed in soluble form. Distinct from the strain-specific MRSA bacteriophage, both recombinant CBD proteins displayed broad-spectrum recognition capability toward all five staphylococcal cassette chromosome mec types of MRSA. Furthermore, they did not display any lytic activity toward the host bacteria, which facilitated the capture of whole MRSA cells with ideal flexibility for downstream manipulation and tracing. For demonstration of their application potential, a flow cytometry method employing the recombinant CBD proteins as the recognition agents was established to detect MRSA within a dynamic range of 1.5 × 102 to 1.5 × 106 cfu mL-1. The method can exclude potential interference from methicillin-sensitive Staphylococcus aureus strains and other bacterial species. The recombinant CBD proteins were also successfully employed in antibiotic susceptibility testing of MRSA with a microplate-based method. The obtained results were consistent with those by the standard broth microdilution method. The satisfying results demonstrated their great application potential in clinical diagnosis and treatment of MRSA-induced infections.


Assuntos
Bacteriófagos/química , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação
12.
Talanta ; 208: 120367, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816709

RESUMO

The investigation of the binding behavior between drug and DNA provides basic information for understanding pharmacological and toxicologic mechanisms of many drugs. Herein, a facile chemiluminescent (CL) method for investigating the binding behavior between salbutamol and calf thymus DNA (ct-DNA) was established by utilizing flow microdialysis sampling technique. In a reaction equilibrium solution of salbutamol and ct-DNA, free salbutamol was extracted by a microdialysis probe, and then injected into a flow-injection CL detection system to quantitate its concentration. The binding constants of salbutamol acquired by Klotz analysis and Scatchard analysis were 2.97 × 104 M-1and 2.99 × 104 M-1, respectively. Salbutamol showed one sort of binding site on ct-DNA. Meanwhile, the three-dimensional spatial structure of the binding mode was investigated by molecular docking. The results indicate that the binding mode of salbutamol to ct-DNA was groove binding. The hydrogen bonds were primary driving force for the direct recognition of salbutamol by ct-DNA. This proof-of-principle method paves a pathway to investigate the binding behavior between small-molecular drug and DNA, and provides a theoretical guidance for designing DNA-targeting drugs.


Assuntos
Albuterol/química , DNA/química , Medições Luminescentes , Microdiálise , Simulação de Acoplamento Molecular , Animais , Conformação de Ácido Nucleico
13.
ACS Appl Mater Interfaces ; 11(39): 35597-35603, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31502440

RESUMO

Nanosized metal-organic frameworks (MOFs) NH2-MIL-53(Al) were synthesized from 2-aminoterephthalic acid (NH2·H2BDC) and AlCl3 by a facile hydrothermal method. The synthesized MOFs displayed good stability and a uniform particle size in a netural medium and were hydrolyzed in alkaline medium to release a large amount of fluorescent ligand NH2·H2BDC. Therefore, they can act as large-capability nanovehicles to load signal molecules for investigating various biorecognition events. In this work, based on the alkaline hydrolysis behavior of MOFs NH2-MIL-53(Al), a sensitive immunoassay method was developed for the detection of aflatoxin B1 (AFB1) by employing them as fluorescent signal probes. With a competitive immunoassay mode on microplate, AFB1 can be detected within a linear range of 0.05-25 ng mL-1. The method was successfully employed to detect AFB1 spiked in Job tears, Polygala tenuifolia and with acceptable recovery values of 83.00-114.00%. The detection results for moldy Fructus xanthii displayed an acceptable agreement with those from the high-performance liquid chromatography method, with relative errors of -14.21 to 3.49%. With the merits of high sensitivity, facile manipulation, and ideal reliability, the approach can also be extended to other areas such as aptasensor and receptor-binding assay.


Assuntos
Aflatoxina B1/análise , Estruturas Metalorgânicas/química , Álcalis , Fluorimunoensaio , Hidrólise , Nanoestruturas
14.
Talanta ; 205: 120130, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450481

RESUMO

Bacterial analysis and antibiotic resistance testing (ART) are of great significance in clinical diagnosis and therapy of bacterial infectious diseases. In this work, a portable antibiotic-affinity chromatographic test strip has been developed for rapid analysis of Staphylococcus aureus (S. aureus) and further applied for ART of this pathogen. Porcine IgG was immobilized on a nitrocellulose membrane for capturing S. aureus based on the selective binding capability of the Fc fragment of IgG toward protein A on the surface of the target bacteria. Fluorescent microspheres modified with teicoplanin (TEI) were applied as signal substances to trace S. aureus utilizing the hydrogen bond conjugation between this antibiotic and Gram-positive bacteria. S. aureus can be analyzed within the concentration range from 1.4 × 103 CFU mL-1 to 1.4 × 107 CFU mL-1. The recovery values for spiked samples were 93.3-110.0%. The obtained results of ART for penicillin, daptomycin, gentamicin, cefoxitin and clindamycin against S. aureus showed agreement with those of traditional broth dilution method. The procedures for bacterial analysis and ART can be accomplished within 20 and 110 min, respectively. The antibiotic-affinity chromatographic test strip showed great promise in point-of-care testing because of its ideal portability and rapidity.


Assuntos
Antibacterianos/farmacologia , Cromatografia de Afinidade/métodos , Farmacorresistência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Staphylococcus aureus/efeitos dos fármacos , Cromatografia de Afinidade/instrumentação , Humanos , Lagos/microbiologia , Testes de Sensibilidade Microbiana/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Fitas Reagentes/química , Fatores de Tempo
15.
Talanta ; 204: 261-265, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357291

RESUMO

As one of the most toxic chemical carcinogens, aflatoxin B1 (AFB1) has attracted extensive attention due to its severe impairment to human health. There exists urgent demand to develop facile and sensitive method for rapid screening of AFB1. Here magnetic beads modified with mouse monoclonal antibody (McAb) were adopted for capture and enrichment of the mycotoxin in sample matrix. Then UV radiation at 365 nm was utilized to induce the enhancement of fluorescent (FL) emission of the captured AFB1 with an addition reaction. The FL signal of the derivative at 435 nm was collected to quantify AFB1. The immunoassay method for AFB1 showed a wide detection range of 1.0-1000 ng mL-1, with a low detection limit of 0.21 ng mL-1 (3σ). It was applied to detect AFB1 in herbal medicines including Astragalus membranaceus and Salvia Miltiorrhiza, with acceptable recovery values of 95.4-107.7%. It shows many merits including facile manipulation, low cost, high sensitivity and ideal selectivity. Due to its simple detection mechanism, the UV-induced FL derivatization-based label-free immunoassay can be furtherly extended to detection of other mycotoxins with similar chemical structures.


Assuntos
Aflatoxina B1/análise , Imunoensaio/métodos , Aflatoxina B1/imunologia , Aflatoxina B1/efeitos da radiação , Anticorpos Monoclonais Murinos/imunologia , Astragalus propinquus/microbiologia , Fluorescência , Separação Imunomagnética/métodos , Limite de Detecção , Salvia miltiorrhiza/microbiologia , Raios Ultravioleta
16.
J Pharm Biomed Anal ; 175: 112785, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31352170

RESUMO

An antibiotic-affinity method was developed for analyzing Staphylococcus on the basis of the strong binding capability of daptomycin towards Gram-positive bacteria cellular membrane, as well as the selective lytic action of lysostaphin towards Staphylococcus. Daptomycin-modified magnetic beads were adopted to enrich Staphylococcus from sample matrix. Afterwards lysostaphin was adopted to lyse Staphylococcus, which can hydrolyze pentaglycine cross-linkers of peptidoglycan composing the cellular wall of Staphylococcus. The concentration of Staphylococcus was quantified by collecting the bioluminescent signal of the released intracellular adenosine triphosphate of the enriched Staphylococcus. Staphylococcus aureus (S. aureus) was analyzed as a model bacterium to study the feasibility of the proof-of-principle work. For bioluminescent analysis of S. aureus with the developed method, the linear range was 5.0 × 102-5.0 × 106 colony forming units mL-1, and the limit of detection was 3.8 × 102 colony forming units mL-1. The analytical procedure consisting of bacterial enrichment, cell lysis and signal collection can be accomplished within 20 min. Some common Gram-positive bacteria and Gram-negative bacteria all indicated very low interference to the analysis of the target bacterium. It has been successfully used to analyze S. aureus in milk as well as physiological saline injection, indicating its application potential for real samples.


Assuntos
Daptomicina/metabolismo , Lisostafina/metabolismo , Staphylococcus aureus/metabolismo , Animais , Antibacterianos/metabolismo , Membrana Celular/metabolismo , Parede Celular/metabolismo , Fenômenos Magnéticos , Leite/metabolismo , Leite/microbiologia
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 215: 340-344, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30852281

RESUMO

A dual sites affinity protocol was developed for fluorescent analysis of Staphylococcus aureus (S. aureus) by employing daptomycin and immunoglobulin G (IgG) as the recognition elements. Pig IgG immobilized on microplate was employed as the first recognition element to capture S. aureus owing to the fact that the Fc segment of mammal IgG can selectively bind with protein A on the surface of the target bacteria. Meanwhile, fluorescein isothiocyanate-conjugated daptomycin was employed as the second recognition element as well as the signal tracer for the target bacteria utilizing the binding capability of daptomycin to Gram-positive bacteria. S. aureus can be analyzed within a concentration range of 5.0 × 103-5.0 × 108 CFU mL-1 with a detection limit of 3.6 × 103 CFU mL-1. The analytical process can be accomplished within 1.5 h by using a pre-coated microplate. The dual sites affinity protocol can exclude the interference led by Gram-negative bacteria and other common Gram-positive bacteria. We have successfully applied it to analyze S. aureus in spiked lake water and physiological saline injection samples, and the recovery values ranged from 88.0% to 120.0%. The results demonstrate its application potential for environmental sanitation and drug safety control.


Assuntos
Daptomicina/química , Corantes Fluorescentes/química , Imunoglobulina G/química , Staphylococcus aureus/química , Anticorpos Antibacterianos/química , Anticorpos Antibacterianos/metabolismo , Anticorpos Imobilizados/química , Anticorpos Imobilizados/metabolismo , Daptomicina/metabolismo , Corantes Fluorescentes/metabolismo , Imunoglobulina G/metabolismo , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Espectrometria de Fluorescência/métodos , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/metabolismo
18.
Talanta ; 195: 706-712, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30625605

RESUMO

Organophosphorus pesticide (OP) residues in agricultural products, herbal medicines and environment have attracted increasing concerns because they cause high healthy risk. Herein, a tyrosinase-mediated photoinduced electron transfer system was constructed for OPs analysis by using dopamine-functionalized upconversion nanoparticles (UCNPs) as fluorescent (FL) sensors. Dopamine quinone was produced by tyrosinase-mediated oxidation of dopamine on the surface of UCNPs, which acted as electron accepter to quench the FL emission of UCNPs. The FL quenching was inhibited by OP since it inhibited the activity of tyrosinase. Chlorpyrifos was used as a model analyte to investigate the feasibility of the FL sensor for the analysis of OPs. Under the optimal conditions, chlorpyrifos can be analysed in a wide range of 1.0 ‒ 1000 ng mL-1, with a detection limit of 0.38 ng mL-1 (3σ). Some other groups pesticides, including organonitrogen pesticide, organochlorine pesticide and chloronicotinyl insecticide all showed negligible interference. The proposed sensor was successfully used to analyse chlorpyrifos spiked in Balloonflower and Angelica with acceptable recovery values of 95.4-120.0%, demonstrating its application potential for real samples. It exhibits some advantages like low cost, high sensitivity and free of autofluorescent interference and photobleaching.


Assuntos
Clorpirifos/análise , Dopamina/análogos & derivados , Corantes Fluorescentes/química , Inseticidas/análise , Metais Terras Raras/química , Nanopartículas/química , Angelica/química , Campanulaceae/química , Clorpirifos/química , Dopamina/química , Inseticidas/química , Monofenol Mono-Oxigenase/química
19.
J Cell Physiol ; 234(8): 13252-13262, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30580435

RESUMO

Although cardiac hypertrophy is widely recognized as a risk factor that leads to cardiac dysfunction and, ultimately, heart failure, the complex mechanisms underlying cardiac hypertrophy remain incompletely characterized. The nuclear receptor peroxisome proliferator-activated receptor δ (PPARδ) is involved in the regulation of cardiac lipid metabolism. Here, we describe a novel PPARδ-dependent molecular cascade involving microRNA-29a (miR-29a) and atrial natriuretic factor (ANF), which is reactivated in cardiac hypertrophy. In addition, we identify a novel role of miR-29a, in which it has a cardioprotective function in isoproterenol hydrochloride-induced cardiac hypertrophy by targeting PPARδ and downregulating ANF. Finally, we provide evidence that miR-29a reduces the isoproterenol hydrochloride-induced cardiac hypertrophy response, thereby underlining the potential clinical relevance of miR-29a in which it may serve as a potent therapeutic target for heart hypertrophy treatment.


Assuntos
Fator Natriurético Atrial/metabolismo , Cardiomegalia/metabolismo , Regulação da Expressão Gênica/fisiologia , MicroRNAs/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Regulação para Baixo , Camundongos , Camundongos Endogâmicos ICR , Miócitos Cardíacos/metabolismo
20.
Anal Chem ; 90(24): 14462-14468, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30481459

RESUMO

Rapid and accurate bacterial detection is crucial to an early diagnosis for treating various infectious diseases. A recombinant tail fiber protein (P069) of the Pseudomonas aeruginosa ( P. aeruginosa) phage was expressed in Escherichia coli. After renaturation at a low temperature, the inclusion body of P069 was successfully transformed to an aqueous soluble protein that retained the capacity for recognizing P. aeruginosa. The recombinant P069 did not show lytic activity to P. aeruginosa, which facilitated the capture and manipulation of bacterial whole cells with a high flexibility for downstream identification and detection. Bioluminescent and fluorescent methods using this biorecognition element allowed P. aeruginosa detection with the detection limits of 6.7 × 102 CFU mL-1 and 1.7 × 102 CFU mL-1, respectively. Moreover, the specificity investigations showed that P069 was a species-specific protein. Therefore, it avoided the potential false negative results originating from the excessive high specificity of phage toward a given strain. It has been successfully applied to detect P. aeruginosa in spiked samples with acceptable recovery values ranging from 88% to 98%. The above results demonstrate that P069 is an ideal biorecognition element for the detection of P. aeruginosa in complicated sample matrixes.


Assuntos
Bacteriófagos , Pseudomonas aeruginosa/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas da Cauda Viral/metabolismo , Técnicas Biossensoriais , Humanos , Ligação Proteica , Pseudomonas aeruginosa/isolamento & purificação , Especificidade da Espécie
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