RESUMO
Anthrax bacillus is a very dangerous zoonotic pathogen that seriously endangers public health. Rapid and accurate qualitative and quantitative detection of its biomarkers, 2,6-dipicolinic acid (DPA), is crucial for the prevention and treatment of this pathogenic bacterium. In this work, a novel Cd-based MOF (TTCA-Cd) has been synthesized from a polycarboxylate ligand, [1,1':2',1â³-terphenyl]-4,4',4â³,5'-tetracarboxylic acid (H4TTCA), and further doped with Tb(III), forming a dual-emission lanthanide-functionalized MOF hybrid (TTCA-Cd@Tb). TTCA-Cd@Tb can be developed as a high-performance ratiometric fluorescent sensor toward DPA with a very low detection limit of 7.14 nM and high selectivity in a wide detection range of 0-200 µM, demonstrating a big advancement and providing a new option for the detection of DPA.
Assuntos
Antraz , Bacillus anthracis , Biomarcadores , Corantes Fluorescentes , Estruturas Metalorgânicas , Ácidos Picolínicos , Térbio , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/síntese química , Térbio/química , Ácidos Picolínicos/análise , Ácidos Picolínicos/química , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Biomarcadores/análise , Antraz/diagnóstico , Cádmio/química , Cádmio/análise , Estrutura Molecular , Limite de Detecção , Espectrometria de FluorescênciaRESUMO
Dipicolinic acid (DPA), as a biomarker for Bacillus anthracis, is highly toxic at trace levels. Rapid and on-site quantitative detection of DPA is essential for maintaining food safety and public health. This work develops a dual-channel self-calibrated fluorescence sensor constructed by the YVO4:Eu and Tb-ß-diketone complex for rapid visual detection of DPA. This sensor exhibits high selectivity, fast response time, excellent detection sensitivity, and the detection limit is as low as 4.5 nM in the linear range of 0-16 µM. A smartphone APP and portable ultraviolet lamp can assemble a mobile fluorescence sensor for on-site analysis. Interestingly, adding Cu2+ ions can quench the fluorescence intensity of Tb3+. In contrast, the addition of cysteine can restore the fluorescence, allowing the accurate detection of Cu2+ ions and cysteine in environmental water and food samples. This work provides a portable sensor that facilitates real-time analysis of multiple targets in food and the environment.
Assuntos
Antraz , Bacillus anthracis , Biomarcadores , Cobre , Cisteína , Análise de Alimentos , Contaminação de Alimentos , Ácidos Picolínicos , Smartphone , Cobre/análise , Cisteína/análise , Bacillus anthracis/isolamento & purificação , Bacillus anthracis/química , Biomarcadores/análise , Contaminação de Alimentos/análise , Antraz/diagnóstico , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Ácidos Picolínicos/análise , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Limite de Detecção , Fluorescência , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodosRESUMO
This study presents methods that can be used to assess the health quality of products containing betalains. The paper compares and verifies data on the phytochemical composition of three different pigmented beetroot cultivars using spectrophotometric, HPLC-DAD, HPTLC and LC-Q-Orbitrap-HRMS techniques. Additionally, we compared the total antioxidant activity in both the cell-free and cellular systems. Betalain contribution to antioxidant activity was also determined using post-column derivatization and it was found that in the case of red beetroot it is about 50%. Photometric measurements are recommended for a simple and inexpensive analysis of the total betacyanin and betaxanthin content. Liquid chromatography techniques produced more precise information on phytochemical composition in the tested samples. The combination of liquid chromatography with high-resolution mass spectrometry produced the largest amount of quantitative and qualitative data; in beetroot samples sixty-four phytochemicals have been identified therefore, this approach is recommended for more detailed metabolomics studies.
Assuntos
Antioxidantes/química , Beta vulgaris/química , Betalaínas/análise , Espectrometria de Massas/métodos , Antioxidantes/análise , Antioxidantes/farmacologia , Betacianinas/análise , Betalaínas/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Células HT29 , Humanos , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/isolamento & purificação , Ácidos Picolínicos/análise , Extratos Vegetais/química , Extratos Vegetais/farmacologia , SoftwareRESUMO
In this study, we reported a facile, one-pot, and "green" synthesis of glutathione-protected gold nanoclusters (GSH@AuNCs) initiated by samarium (Sm3+) lanthanides for the first time. Sm3+ lanthanides more efficiently induced the formation of GSH@AuNCs with significantly enhanced luminescence than other lanthanides or heavy metal ions (Cd2+, Pb2+) did. Using this strategy, a detection for Sm3+ was made with a linearity range of (10.0-100.0 µM) and a limit of detection (LOD) of 0.5 µM. The Sm3+-based GSH@AuNCs were characterized by eco-friendliness, photostability, and low-cost synthesis with low biological toxicity and had great potential in the application for biosensing and bioimaging. They were successfully employed in the detection of dipicolinic acid (DPA), a well-reported biomarker for sensing potential infection by strongly hazardous anthrax spores. A good linear response was obtained for DPA detection ranging from 1.0 to 120.0 µM with a low LOD of 0.1 µM, which was much lower (600 times) than the infectious dosage of anthrax spores (6 × 10-5 M). The detection was due to the strong binding affinity and strong chelation capability of DPA to Sm3+ lanthanides, which caused the dissociation of the aggregates with an obvious decrease or even a turning-off effect of their luminescence.
Assuntos
Bacillus anthracis/química , Medições Luminescentes , Ácidos Picolínicos/análise , Samário/química , Esporos Bacterianos/química , Biomarcadores/análise , Glutationa/química , Ouro/química , Nanopartículas Metálicas/química , Estrutura Molecular , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
A fluorescence off-on sensing platform was developed based on thioglycolic acid-stabilized cadmium sulfide quantum dots (CdS QDs) as fluorescence probe for the sensitive and selective detection of 2,6-pyridinedicarboxylic acid (DPA) in spores. The fluorescence emission intensity of the quantum dots at 650 nm when excited at 460 nm was first quenched by mixing with europium ions (Eu3+) and then recovered after the addition of DPA. The interaction of DPA with Eu3+ relieved the quenching effect of Eu3+ toward CdS QDs. As the DPA concentration increases, the color of the probe changes from colorless to red. The method exhibits a wide linear range from 1 to 120 µM for DPA determination, with a detection limit of 0.2 µM. The CdS QDs based nanoprobe was successfully applied for sensitive determination of DPA released from bacteria spores. In this case, the detection limit is 3.5 × 104 CFU·mL-1. Graphical abstract An off-on fluorescence sensor for detecting anthrax markers -2,6-pyridinedicarboxylic acid though restoring the fluorescence of cadmium sulfide quantum dots quenching by europium ions.
Assuntos
Antraz/diagnóstico , Compostos de Cádmio/química , Corantes Fluorescentes/química , Ácidos Picolínicos/análise , Pontos Quânticos/química , Sulfetos/química , Bacillus subtilis/química , Biomarcadores/análise , Fluorescência , Corantes Fluorescentes/síntese química , Solubilidade , Espectrometria de Fluorescência , Esporos Bacterianos/química , Tioglicolatos/química , Água/químicaRESUMO
The Mediterranean basin is one of the regions heavily affected by jellyfish bloom phenomena, mainly due to the presence of scyphozoans, such as Rhizostoma pulmo. The jellyfish have few natural predators, and their bodies represent an organic-rich substrate that can support rapid bacterial growth with great impact on the structure of marine food webs. In Asiatic countries, jellyfish are widely studied for their health benefits, but their nutritional and nutraceutical values still remain poorly characterized. In this study, the differences in the 1H NMR spectroscopy metabolic profiles of R. pulmo female gonads and body fractions (including umbrella and oral arms), in different sampling periods, were studied. For each body compartment both lipid and aqueous extracts were characterized and their 1H NMR metabolic profiles subjected to multivariate analysis. From a statistical analysis of the extracts, a higher contents of ω-3 polyunsaturated fatty acids (PUFAs), amino acid and osmolytes (homarine, betaine, taurine) with important roles in marine invertebrates were observed in female gonads, whereas umbrella and oral arms showed similar metabolic profiles. These results support a sustainable exploitation of the jellyfish for the extraction of bioactive compounds useful in nutraceutical, nutricosmetics, and functional food fields.
Assuntos
Espectroscopia de Prótons por Ressonância Magnética/métodos , Animais , Betaína/análise , Cnidários/química , Ácidos Graxos Insaturados/análise , Feminino , Gônadas/química , Análise Multivariada , Ácidos Picolínicos/análise , Cifozoários/química , Taurina/análiseRESUMO
Reduction of bioactive compounds sensitive to heat, light and oxygen could be attributed to drying. The effectiveness of microwave pretreatment at 525 or 420 W and the ohmic heating at 17.5 V/cm over the properties of beetroot powder were compared. This study aimed to develop novel hybrid drying methods. The effects of microwave and ohmic heating pre-treatment and subsequent microwave-convection drying were studied. Several investigations were performed, such as phenolic content, antioxidant activity, betalains content and color. The samples pretreated by microwave have registered higher polyphenols content and antioxidant capacity than those ohmically heated. The ohmic heating pretreated samples registered highest values for ΔL = 7.33-7.65 and ΔH = 8.18-10.02. Confocal microscopy reveals that the MW heating favors cellular lysis and cell content agglutinates. In conclusion, even if the MW preheating has certain disadvantages, in some cases it provides increased bioavailability generated by the vegetal cell disruption and the release of the bioactive compounds.
Assuntos
Beta vulgaris/química , Dessecação/métodos , Pós/química , Antioxidantes/análise , Antioxidantes/química , Betacianinas/análise , Betalaínas/análise , Betalaínas/química , Cor , Convecção , Temperatura Alta , Micro-Ondas , Ácidos Picolínicos/análise , Polifenóis/análise , Polifenóis/químicaRESUMO
Based on a BODIPY molecular rotor and a zinc-dipicolylamine receptor, we designed a fluorogenic probe for the detection of apoptosis. Being poorly emissive in solution and with healthy cells, it selectively binds phosphatidylserine of early apoptotic cells and internalizes into late apoptotic cells, lighting up its green fluorescence.
Assuntos
Apoptose , Compostos de Boro/química , Corantes Fluorescentes/química , Compostos Organometálicos/análise , Ácidos Picolínicos/análise , Biomarcadores Tumorais/análise , Compostos de Boro/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Corantes Fluorescentes/metabolismo , Células HeLa , Humanos , Fosfatidilserinas/química , Fosfatidilserinas/metabolismoRESUMO
Bacillus spp. are spore-forming bacteria, and some of them, including Bacillus cereus and Bacillus anthracis, are pathogens. Dipicolinic acid (DPA) has been recognized as a biomarker for spore-forming bacteria. Thus, developing rapid sensing methods to spot the presence of DPA in suspicious samples is significant. In this study, we employ complexes of glutathione-capped gold nanoclusters (Au@GSH NCs) with Cu2+ as sensing probes against DPA. Au@GSH NCs possess orange-reddish fluorescence. However, their fluorescence is significantly quenched in the presence of Cu2+. In the presence of DPA, the fluorescence of Au@GSH NCs can be restored because DPA can easily remove Cu2+ on the NCs through chelation based on the high formation constant (log K = 7.97) between Cu2+ and DPA. Therefore, on the basis of this fact, Au@GSH NC-Cu2+ complexes are used as turn-on fluorescence probes against DPA. Unlike most of the existing sensing methods, the developed Au@GSH-Cu2+-based sensing method is not affected by the presence of phosphates, which can be commonly found in real samples. The limit of detection of using the developed sensing method toward DPA can reach as low as â¼19 nM. In addition, we also demonstrate the feasibility of using the developed sensing method for detection and quantification of DPA in soil samples and B. cereus spore lysates.
Assuntos
Corantes Fluorescentes/química , Ouro/química , Nanopartículas Metálicas/química , Ácidos Picolínicos/análise , Espectrometria de Fluorescência/métodos , Bacillus cereus/isolamento & purificação , Biomarcadores/análise , Quelantes/análise , Quelantes/química , Cobre/química , Fluorescência , Glutationa/química , Limite de Detecção , Ácidos Picolínicos/química , Solo/químicaRESUMO
The sensitive, selective and point-of-care detection of dipicolinic acid (DPA) is of great significance for the prevention of the anthrax virus and the containment of bioterrorism. In this work, a multi-color fluorescent nanoprobe composed of lanthanides and magnetic nanoparticles (Fe3O4@CePO4:Tb-EDTA-Eu) has been designed, in which the portion of Fe3O4@CePO4:Tb can be used as the internal stable signal of green fluorescence, while the EDTA-Eu part can be used as the sensitive reaction signal for monitoring DPA. Upon the addition of DPA, the red fluorescence of Eu3+ ions is significantly enhanced, while the fluorescent color of the nanoprobes can change from green to red (such as yellow-green, orange-yellow and orange-red), achieving visual multi-color fluorescent detection even by the naked eye. By using the magnetic separation method, the composites can be easily purified for point-of-care testing. More importantly, the nanoprobe fixed test pieces enable real-time analysis of DPA by using an easy-to-access color-scanning application on a smartphone. Furthermore, the fluorescence intensity can be quenched by the addition of Cu2+, which leads to a rewritable nanosensor and can be used in the detection of cysteine (Cys) with high sensitivity. With the addition of Cys, this erasable nano detection platform can also display the original multi-color visual point-of-care detection. With further optimization, this new type of multi-color fluorescent assay is promising in point-of-care clinics for multi-target diagnostics.
Assuntos
Antraz/prevenção & controle , Bioterrorismo/prevenção & controle , Corantes Fluorescentes/química , Ácidos Picolínicos/análise , Sistemas Automatizados de Assistência Junto ao Leito , Smartphone , Armas Biológicas , Humanos , Elementos da Série dos Lantanídeos , Magnetismo , Nanopartículas/análiseRESUMO
The research aimed to expand the knowledge on the use of natural bioactive compounds for food preservation. First-crop fruit of prickly pear were subjected to water extraction and evaluated for total polyphenol content, antioxidant activity, in vitro antimicrobial performance against food spoilage and pathogenic bacteria, and betacyanin and betaxanthin content. The extract was then applied by dipping technique to packed sliced beef, to evaluate its effect on physical and chemical parameters, color and texture maintenance, as well as on microbial growth during shelf life at domestic storage conditions. The in vitro antimicrobial assay of prickly pear fruit extract evidenced a wide spectrum activity, since it inhibited the growth of all Gram positive and negative targeted strains. In vivo application of extract effectively reduced microbial growth during refrigerated storage; total mesophilic count was maintained below the limit established by Commission Regulation (EC) No 2073/2005 of 5â¯×â¯106 log CFU/g of beef up to 8â¯d, in comparison to control sample that reached the mentioned limit after 4â¯d. Moreover, extract addition preserved beef color and texture over the considered storage period, supporting the potential prospect to utilize the extract to improve overall quality and to prolong domestic shelf life of sliced beef.
Assuntos
Antioxidantes/farmacologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Opuntia/química , Extratos Vegetais/farmacologia , Carne Vermelha/microbiologia , Animais , Betacianinas/análise , Bovinos , Contagem de Colônia Microbiana , Cor , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/isolamento & purificação , Concentração de Íons de Hidrogênio , Ácidos Picolínicos/análise , Polifenóis/análiseRESUMO
Bioprospection of marine invertebrates has been predominantly biased by the biological richness of tropical regions, thus neglecting macro-organisms from temperate ecosystems. Species that were not the object of studies on their biochemical composition include the Heterobranchia gastropods Armina maculata, Armina tigrina and Aglaja tricolorata, inhabitants of the Portuguese Atlantic coastal waters. Here, we present for the first time the fatty acid profile of neutral lipids and homarine content of these three species. Qualitative and quantitative differences in the fatty acid content among species points to the existence of a fatty acid profile of neutral lipids, particularly of each genus. The results from cytotoxicity assays, using the acetonic extracts of the gastropods on human gastric adenocarcinoma (AGS) and human lung adenocarcinoma (A549) cell lines, revealed a pronounced cytotoxic effect of the A. tigrina extract on both cell lines (IC50 values of 68.75 and 69.77 µg mL−1 for AGS and A549, respectively). It is worth noting the significant reduction of NO levels in LPS-challenged RAW 264.7 macrophages exposed to A. tricolorata extract, at concentrations as low as 125 µg mL−1.
Assuntos
Anti-Inflamatórios/análise , Antineoplásicos/análise , Ácidos Graxos/análise , Gastrópodes/metabolismo , Macrófagos/efeitos dos fármacos , Ácidos Picolínicos/análise , Células A549 , Animais , Anti-Inflamatórios/metabolismo , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ácidos Graxos/metabolismo , Humanos , Lipopolissacarídeos/efeitos adversos , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Óxido Nítrico/metabolismo , Ácidos Picolínicos/metabolismo , Células RAW 264.7RESUMO
Dipicolinic acid (DPA) can cause neurotoxicity and is abundant in bacterial spores. Although analytical methods have been reported for DPA detection with high sensitivity, their selectivity toward DPA is declined greatly in the presence of phosphates in the samples. In this study, we developed an approach for DPA detection that is not affected by the presence of phosphates. A colorimetric method based on the use of gold nanoparticles (AuNP) complexed with Ca2+ as sensing agents was explored for DPA detection. Calcium ions and glutathione-capped gold nanoparticles (AuNPs@GSH) can easily form complexes (Ca2+-AuNP@GSH) through GSH-Ca2+ chelation, leading to the aggregation of AuNPs@GSH. The aggregation resulting from the complexes of AuNPs@GSH and Ca2+ can be reversed with the addition of DPA owing to the high formation constant (log Kf = 4.4) between DPA and Ca2+. Furthermore, the color of AuNPs@GSH changes from red to purple when complexed with Ca2+, returning to red upon addition of DPA. The limit of detection of this sensing method toward DPA was estimated to be as low as ~ 2 µM. The feasibility of using the sensing method for quantitative detection of DPA in soil and Bacillus cereus spore samples was also demonstrated. Graphical abstract A AuNP-based colorimetric sensing method against dipicolinic acid is developed.
Assuntos
Bacillus cereus/química , Colorimetria/métodos , Ouro/química , Nanopartículas Metálicas/química , Ácidos Picolínicos/análise , Solo/química , Esporos Bacterianos/química , Cálcio/química , Glutationa/químicaRESUMO
An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA-AuNPs@Tb-AMP (BSA, bovine serum albumin; AMP, adenosine 5'-monophosphate; AuNPs, Au nanoparticles) metal-organic framework (MOF) nanostructures were synthesized by encapsulating BSA-AuNPs into Tb-AMP MOFs for the detection of 2,6-pyridinedicarboxylic acid (DPA) and Hg2+ . DPA could strongly co-ordinate with Tb3+ to replace water molecules from the Tb3+ center and accordingly enhanced the fluorescence of Tb-AMP MOFs. The fluorescence of BSA-AuNPs at 405 nm remained constant. While the fluorescence of BSA-AuNPs at 635 nm was quenched after Hg2+ was added, the fluorescence of Tb-AMP MOFs remained constant. Accordingly, a ratiometric fluorescence nanosensor was constructed for detection of DPA and Hg2+ . The ratiometric nanosensor exhibited good selectivity to DPA over other substances. The F545 /F405 linearly increased with increase of DPA concentration in the range of 50 nM to 10 µM with a detection limit as low as 17.4 nM. F635 /F405 increased linearly with increase of Hg2+ concentration ranging from 50 nM to 1 µM with a detection limit as low as 20.9 nM. Additionally, the nanosensor could be successfully applied for the determination of DPA and Hg2+ in running water.
Assuntos
Mercúrio/análise , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Ácidos Picolínicos/análise , Espectrometria de Fluorescência/métodos , Monofosfato de Adenosina/química , Ouro , Limite de Detecção , Soroalbumina Bovina/química , Térbio/química , Água/análise , Poluentes Químicos da Água/análiseRESUMO
The aim of the present study is to compare three cultivars of prickly pear fruits ("Sanguigna" red, "Sulfarina" yellow and "Muscaredda" white) regarding the quality parameters of antioxidant activity, phenolic compounds, betalains and ascorbic acid (vitamin C). Depending on the crop operation, these cultivars are represented by "Agostane" and "Bastardoni" and are located at an altitude between 150 and 750 m, above sea level. Their antioxidant activity was evaluated by ORAC assay. Total phenolic compounds, betalains and ascorbic acid recovered from pulp juice, were determined by a spectrophotometric analysis. The results indicate that the different cultivars of prickly pear possess antioxidant activity in function of the type of the adopted practice. These fruits were derived from the practice of scozzolatura, by dropping the berries to encourage a second bloom of the plant. Among the "Bastardoni", the "Sulfarina" possesses the highest antioxidant activity.
Assuntos
Antioxidantes/química , Frutas/química , Opuntia/química , Compostos Fitoquímicos/química , Ácido Ascórbico/análise , Betalaínas/análise , Ácidos Picolínicos/análise , Pigmentos Biológicos/análise , Extratos Vegetais/análise , Polifenóis/análise , EspectrofotometriaRESUMO
A surface-enhanced Raman spectroscopy (SERS) assay has been designed to detect Bacillus anthracis spores. The assay consists of silver nanoparticles embedded in a porous glass structure that have been functionalized with ATYPLPIR, a peptide developed to discriminately bind B. anthracis versus other species of Bacillus. Once bound, acetic acid was used to release the biomarker dipicolinic acid from the spores, which was detected by SERS through the addition of silver colloids. This SERS assay was used to selectively bind B. anthracis with a 100-fold selectivity versus B. cereus, and to detect B. anthracis Ames at concentrations of 1000 spores per mL within 15 minutes. The SERS assay measurements provide a basis for the development of systems that can detect spores collected from the air or from water supplies.
Assuntos
Antraz/microbiologia , Bacillus anthracis/isolamento & purificação , Análise Espectral Raman/métodos , Esporos Bacterianos/isolamento & purificação , Sequência de Aminoácidos , Bacillus anthracis/química , Humanos , Nanopartículas/química , Peptídeos/química , Ácidos Picolínicos/análise , Prata/química , Esporos Bacterianos/químicaRESUMO
Zinc(II)-bis(dipicolylamine) (Zn-BDPA) coordination complexes selectively target the surfaces of dead and dying mammalian cells, and they have promise as molecular probes for imaging cell death. A necessary step toward eventual clinical imaging applications is the development of next-generation Zn-BDPA complexes with enhanced affinity for the cell death membrane biomarker, phosphatidylserine (PS). This study employed an iterative cycle of library synthesis and screening, using a novel rapid equilibrium dialysis assay, to discover a modified Zn-BDPA structure with high and selective affinity for vesicles containing PS. The lead structure was converted into a deep-red fluorescent probe and its targeting and imaging performance was compared with an unmodified control Zn-BDPA probe. The evaluation process included a series of FRET-based vesicle titration studies, cell microscopy experiments, and rat tumor biodistribution measurements. In all cases, the modified probe exhibited comparatively higher affinity and selectivity for the target membranes of dead and dying cells. The results show that this next-generation deep-red fluorescent Zn-BDPA probe is well suited for preclinical molecular imaging of cell death in cell cultures and animal models. Furthermore, it should be possible to substitute the deep-red fluorophore with alternative reporter groups that enable clinically useful, deep-tissue imaging modalities, such as MRI and nuclear imaging.
Assuntos
Neoplasias da Mama/patologia , Imagem Molecular/métodos , Sondas Moleculares/análise , Sondas Moleculares/síntese química , Compostos Organometálicos/análise , Compostos Organometálicos/síntese química , Ácidos Picolínicos/análise , Ácidos Picolínicos/síntese química , Animais , Células CHO , Morte Celular , Linhagem Celular Tumoral , Cricetulus , Transferência Ressonante de Energia de Fluorescência , Humanos , Masculino , Sondas Moleculares/química , Sondas Moleculares/farmacocinética , Estrutura Molecular , Compostos Organometálicos/química , Compostos Organometálicos/farmacocinética , Ácidos Picolínicos/química , Ácidos Picolínicos/farmacocinética , Ratos , Ratos Wistar , Distribuição TecidualRESUMO
AIMS: To determine how hydrated Bacillus anthracis spores are killed in a high-temperature gas environment (HTGE), and how spores of several Bacillus species including B. anthracis are killed by UV radiation, dry heat, wet heat and desiccation. METHODS AND RESULTS: Hydrated B. anthracis spores were HTGE treated at c. 220°C for 50 ms, and the treated spores were tested for germination, mutagenesis, rupture and loss of dipicolinic acid. Spores of this and other Bacillus species were also examined for mutagenesis by UV, wet and dry heat and desiccation. There was no rupture of HTGE-treated B. anthracis spores killed 90-99·9%, no mutagenesis, and release of DPA and loss of germination were much slower than spore killing. However, killing of spores of B. anthracis, Bacillus thuringiensis and Bacillus subtilis by UV radiation or dry heat, but not wet heat in water or ethanol, was accompanied by mutagenesis. CONCLUSIONS: It appears likely that HTGE treatment kills B. anthracis spores by damage to spore core proteins. In addition, various killing regimens inactivate spores of a number of Bacillus species by the same mechanisms. SIGNIFICANCE AND IMPACT OF THE STUDY: This work indicates how hydrated spores treated in a HTGE such as might be used to destroy biological warfare agent stocks are killed. The work also indicates that mechanisms whereby different agents kill spores are similar with spores of different Bacillus species.
Assuntos
Bacillus anthracis , Bacillus subtilis , Bacillus thuringiensis , Descontaminação , Temperatura Alta , Bacillus anthracis/química , Bacillus anthracis/genética , Bacillus anthracis/fisiologia , Bacillus anthracis/ultraestrutura , Bacillus subtilis/genética , Bacillus thuringiensis/genética , Dano ao DNA , Gases , Mutagênese , Ácidos Picolínicos/análise , Esporos Bacterianos/química , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Bacterianos/ultraestrutura , Raios UltravioletaRESUMO
We present the synthesis of highly anisotropic nickel nanowires (NWs) and large area, free-standing carpets extending over cm(2) area by simple solution phase chemistry. The materials can be post-synthetically manipulated to produce hybrid tubes, wires, and carpets by galvanic exchange reactions with Au(3+), Ag(+), Pt(2+), and Pd(2+). All of these structures, especially the hybrid carpets and tubes, have been prepared in bulk and are surface enhanced Raman scattering (SERS) active substrates. Molecules of relevance such as dipicolinic acid (constituting 5-15% of the dry weight of bacterial spores of Bacillus anthracis), dinitrotoluene, hexahydro-1,3,5-triazine (RDX), and trinitrotoluene at nanomolar concentrations have been detected. An enhancement factor of â¼10(10) was observed for the Ni-Au nanocarpet. The reusability of the Ni-Au nanocarpet for SERS applications was tested 5 times without affecting the sensitivity. The reusability and sensitivity over large area have been demonstrated by Raman microscopy. Our method provides an easy and cost effective way to produce recyclable, large area, SERS active substrates with high sensitivity and reproducibility which can overcome the limitation of one-time use of traditional SERS substrates.
Assuntos
Armas Biológicas , Substâncias Explosivas/análise , Nanofios/química , Níquel/química , Análise Espectral Raman , Bacillus anthracis/fisiologia , Nanofios/ultraestrutura , Ácidos Picolínicos/análise , Esporos Bacterianos/isolamento & purificaçãoRESUMO
A supramolecular platform based on self-assembled monolayers (SAMs) has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detection. A Eu(III)-EDTA complex was bound to ß-cyclodextrin monolayers via orthogonal supramolecular host-guest interactions. The self-assembly of the Eu(III)-EDTA conjugate and naphthalene ß-diketone as an antenna resulted in the formation of a highly luminescent lanthanide complex on the microchannel surface. Detection of different phosphate anions and aromatic carboxylic acids was demonstrated by monitoring the decrease in red emission following displacement of the antenna by the analyte. Among these analytes, adenosine triphosphate (ATP) and pyrophosphate, as well as dipicolinic acid (DPA) which is a biomarker for anthrax, showed a strong response. Parallel fabrication of five sensing SAMs in a single multichannel chip was performed, as a first demonstration of phosphate and carboxylic acid screening in a multiplexed format that allows a general detection platform for both analyte systems in a single test run with µM and nM detection sensitivity for ATP and DPA, respectively.