RESUMEN
Garlic is a well-known example of natural self-defence system consisting of an inactive substrate (alliin) and enzyme (alliinase) which, when combined, produce highly antimicrobial allicin. Increase of alliinase stability and its activity are of paramount importance in various applications relying on its use for in-situ synthesis of allicin or its analogues, e.g., pulmonary drug delivery, treatment of superficial injuries, or urease inhibitors in fertilizers. Here, we discuss the effect of temperature, pH, buffers, salts, and additives, i.e. antioxidants, chelating agents, reducing agents and cosolvents, on the stability and the activity of alliinase extracted from garlic. The effects of the storage temperature and relative humidity on the stability of lyophilized alliinase was demonstrated. A combination of the short half-life, high reactivity and non-specificity to particular proteins are reasons most bacteria cannot deal with allicin's mode of action and develop effective defence mechanism, which could be the key to sustainable drug design addressing serious problems with escalating emergence of multidrug-resistant (MDR) bacterial strains.
Asunto(s)
Liasas de Carbono-Azufre/metabolismo , Fenómenos Químicos , Disulfuros/metabolismo , Ajo/enzimología , Ácidos Sulfínicos/metabolismo , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/ultraestructura , Biocatálisis/efectos de los fármacos , Tampones (Química) , Disulfuros/química , Estabilidad de Enzimas/efectos de los fármacos , Liofilización , Concentración de Iones de Hidrógeno , Cinética , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Estereoisomerismo , Ácidos Sulfínicos/química , Temperatura , Factores de TiempoRESUMEN
The aim of the present investigation was to determine the active ingredients in Amaranthus tricolor L. leaves and develop a biological pesticide. Organic solvent extraction, column chromatography, liquid chromatography, ODS-C18 reverse elution, Sephadex LH-20 gel filtration, H spectrum, and C spectrum were used to isolate the pure product for an assessment of the agricultural activity and bacteriostatic mechanisms. The results showed that the activity of the crude extract following carbon powder filtration was 1.63-fold that of the non-filtered extract. Further isolation was performed to obtain two pure products, namely, hydroxybenzoic acid (HBA) and benzo[b]furan-2-carboxaldehyde (BFC), and their molecular formulas and molecular weights were C7H6O3 and 138.12, and C9H6O2 and 146.12, respectively. Our study is the first to determine that HBA has bacteriostatic activity (MIC 125 µg/mL) and is also the first to isolate BFC from A. tricolor. The ultrastructure observation results showed that HBA caused the bacteria to become shriveled, distorted, and deformed, as well as exhibit uneven surfaces. After HBA treatment, 70 differentially expressed metabolites were detected in the bacteria, of which 9 were downregulated and 61 were upregulated. The differentially expressed metabolites were mainly strigolactones, organic acids and derivatives, fatty acids, benzene and substituted benzene derivatives, amino acids and associated metabolites, and alcohols and amines. Among all of the downregulated differentially expressed metabolites, MEDP1280 was the most critical, as it participates in many physiological and biochemical processes. The enrichment analysis showed that the differentially expressed metabolites mainly participate in tyrosine metabolism, biosynthesis of amino acids, cysteine and methionine metabolism, and arginine and proline metabolism. Additionally, HBA was found to disrupt cell membrane permeability and integrity, causing the leakage of substances and apoptosis. The physiological and biochemical test results showed that HBA could increase the pyruvate levels in bacteria but could decrease the activities of respiratory enzymes (malate dehydrogenase (MDH) and NADH oxidase) and antioxidant enzymes (superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX)). Inverse molecular docking was used to study the binding between HBA and respiratory and antioxidant enzymes. The results showed that HBA could bind to MDH, NADH oxidase, SOD, and GSH-PX, suggesting that these enzymes may be the effector targets of HBA. Conclusion: The optimal active ingredient in A. tricolor that can inhibit Acidovorax avenae subsp. citrulli was identified as HBA. HBA mainly disrupts the cell membrane, damages the metabolic system, and inhibits respiration and antioxidant enzyme activity to control bacterial growth. These results provide a reference for the further development of biological pesticides.
Asunto(s)
Acetatos/química , Amaranthus/química , Antibacterianos/farmacología , Comamonadaceae/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Antifúngicos/farmacología , Antioxidantes/metabolismo , Bacterias/efectos de los fármacos , Bacterias/ultraestructura , Espectroscopía de Resonancia Magnética con Carbono-13 , Permeabilidad de la Membrana Celular/efectos de los fármacos , Ésteres/aislamiento & purificación , Hidroxibenzoatos/química , Hidroxibenzoatos/farmacología , Metaboloma/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Espectroscopía de Protones por Resonancia Magnética , Ácido Pirúvico/metabolismoRESUMEN
ETHNOPHARMACOLOGY RELEVANCE: Cinnamomum camphora (Linn.) Presl (C. camphora) is one of the oldest herbal medicines used as a traditional medicine, owning a wide range of biological functions including anti-bacterial, anti-oxidative, anti-fungal, anti-inflammatory, insecticidal and repellent activities. OBJECTIVE: The aim of this study was to investigate the antibacterial activity and mechanism of action of the essential oil (EO) from C. camphora. MATERIALS AND METHODS: The EO was isolated from the leaves of C. camphora by hydrodistillation, and the chemical compositions of the EO were analyzed by gas chromatography-mass spectrometry (GC-MS). The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values of the EO were estimated by the microbroth dilution method. Growth curve was investigated by turbidimetry. Apoptosis was measured by flow cytometry. Morphological change of bacteria was observed by field emission scanning electron microscopy and transmission electron microscopy. The integrity of cell membrane was evaluated by NanoDrop and BCA Protein Assay Kit. The methicillin-resistant Staphylococcus aureus (MRSA) metabolic profile in the presence of the EO was explored by GC-MS-based metabolomics. Isocitrate dehydrogenase (ICDH), α-ketoglutarate dehydrogenase (α-KGDH), succinic dehydrogenase (SDH) and malic dehydrogenase (MDH) activities were detected by commercial kits. RESULTS: The main components of the EO from the leaves of C. camphora were identified to be linalool (26.6%), eucalyptol (16.8%), α-terpineol (8.7%), isoborneol (8.1%), ß-phellandrene (5.1%), and camphor (5.0%). The EO had good activity against MRSA, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Salmonella gallinarum and Escherichia coli. MRSA was selected as the model bacterium to illustrate antibacterial mechanism of action of the EO, and the MIC and MBC values was 0.8 and 1.6 mg/mL, respectively. Apoptosis rate of MRSA increased in a concentration-dependent manner after the addition of EO. The cell morphology was damaged by the EO. There were 74 significantly different metabolites, including 29 upregulated and 45 downregulated metabolites in the result of metabolomics evaluation. Seven pathways were enriched by shared differential metabolites. The EO enhanced the activity of ICDH by 47.35%, while weaken MDH, SDH and α-KGDH by 72.63%, 31.52% and 63.29%, respectively. CONCLUSIONS: The EO from C. camphora showed anti-MRSA activity via damaging cell membranes and disturbing the amino metabolism.
Asunto(s)
Antibacterianos/farmacología , Cinnamomum camphora , Aceites Volátiles/farmacología , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Bacterias/metabolismo , Bacterias/ultraestructura , Metabolómica , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Aceites Volátiles/química , Fitoquímicos/análisis , Fitoquímicos/farmacología , Hojas de la PlantaRESUMEN
High salinity can strongly inhibit microbial activity and decrease the sedimentation ability of activated sludge. The combination of biofilm and membrane bioreactor is a practical approach towards effective removal of pollutants and low fouling rate. An integrated biofilm-membrane bioreactor (BMBR) treating mustard tuber wastewater was investigated. An average COD removal efficiency of 94.81% and ammonium removal efficiency of 96.84% were achieved at an organic load of 0.5 kg COD/(m3·d). However, the reactor showed a relatively low efficiency in total nitrogen and soluble phosphorus removal due to the lack of anaerobic environment. The increase of influent organic load resulted in a performance degradation because a balance between the degradation ability and pollution has been reached. Images of scanning electron microscopy revealed that halophilic bacteria were the dominant microbe in the system that leads to a loose sludge structure and declined settling properties. It was found that membrane fouling was the consequence of the interaction of microbial activities and NaCl crystallization.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Reactores Biológicos/microbiología , Membranas , Compuestos Orgánicos/metabolismo , Salinidad , Aguas Residuales , Purificación del Agua/métodos , Aerobiosis , Compuestos de Amonio/análisis , Anaerobiosis , Ascomicetos , Bacterias/metabolismo , Bacterias/ultraestructura , Análisis de la Demanda Biológica de Oxígeno , Metagenoma , Microscopía Electrónica de Rastreo , Nitrógeno/análisis , Fósforo/análisisRESUMEN
Over-prescription and improper use of antibiotics has led to the emergence of bacterial resistance, posing a major threat to public health. There has been significant interest in the development of alternative therapies and agents to combat antibiotic resistance. We report the preparation of recyclable magnetic iron oxide nanoparticles grafted with charged cobaltocenium-containing metallopolymers by surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization. ß-Lactam antibiotics were then conjugated with metallopolymers to enhance their vitality against both Gram-positive and Gram-negative bacteria. The enhanced antibacterial activity was a result of synergy of antimicrobial segments that facilitate the inhibition of hydrolysis of antibiotics and local enhancement of antibiotic concentration on a nanoparticle surface. These magnetic nanoparticles can be recycled numerous times without losing the initial antimicrobial potency. Studies suggested negligible toxicity of metallopolymer-grafted nanoparticles to red blood cells and minimal tendency to induce resistance in bacteria.
Asunto(s)
Antibacterianos/farmacología , Nanopartículas de Magnetita/química , Metales/farmacología , Polímeros/farmacología , Bacterias/efectos de los fármacos , Bacterias/ultraestructura , Farmacorresistencia Bacteriana/efectos de los fármacos , Compuestos Férricos/química , Nanopartículas de Magnetita/ultraestructura , Pruebas de Sensibilidad Microbiana , Polimerizacion , Dióxido de Silicio/síntesis química , Dióxido de Silicio/química , Factores de TiempoRESUMEN
A serine protease was purified from the leaves of Wrightia tinctoria by sequential flow through method comprising screening, optimization, ammonium sulfate precipitation, gel filtration and ion exchange column chromatography. The yield and purification fold obtained were 11.58% and 9.56 respectively. A single band of serine protease was visualized on SDS-PAGE and 2-D gel electrophoretic analyses were revealed with the molecular mass of 38.5 kDa. Serine protease had an optimum pH of 8.0 and was stable at 45°C with high relative protease activity. The addition of metal ions such as Mg2+ and Mn2+ exhibits a high relative activity. Serine protease had a potent antibacterial activity against both Gram-positive and Gram-negative bacteria. A 10 µg/ml of serine protease was tested against S. aureus, M. luteus, P. aeruginosa and K. pneumoniae which had 21, 20, 18 and 17 mm of zone of inhibition respectively. Serine protease from W. tinctoria degrades the peptidoglycan layer of bacteria which was visualized by transmission electron microscopic analysis.
Asunto(s)
Antibacterianos/aislamiento & purificación , Apocynaceae/enzimología , Serina Proteasas/aislamiento & purificación , Sulfato de Amonio/química , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/ultraestructura , Tampones (Química) , Permeabilidad de la Membrana Celular/efectos de los fármacos , Precipitación Química , Cromatografía de Afinidad , Cromatografía en Gel , Electroforesis en Gel Bidimensional , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Iones , Metales/farmacología , Pruebas de Sensibilidad Microbiana , Peso Molecular , Extractos Vegetales/química , Hojas de la Planta/enzimología , Inhibidores de Proteasas/farmacología , Solventes/farmacología , Especificidad por Sustrato/efectos de los fármacos , TemperaturaRESUMEN
Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 µg/mL) and 18 ± 1.6 mm (MIC = 12.50 µg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 µg/mL) and Bacillus subtilus (MIC = 12.50 µg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Tecnología Química Verde , Nanopartículas del Metal/administración & dosificación , Plata , Antibacterianos/química , Bacterias/metabolismo , Bacterias/ultraestructura , Potenciales de la Membrana/efectos de los fármacos , Nanopartículas del Metal/química , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Espectroscopía de Fotoelectrones , Extractos Vegetales/química , Extractos Vegetales/farmacología , Especies Reactivas de Oxígeno/metabolismo , Plata/química , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos XRESUMEN
The aim of this study was to determine antibacterial activity of S. polyanthum L. (salam) leaves extract foodborne pathogens. All the foodborne pathogens were inhibited after treating with extract in disk diffusion test with range 6.67 ± 0.58-9.67 ± 0.58 mm of inhibition zone. The range of MIC values was between 0.63 and 1.25 mg/mL whereas MBC values were in the range 0.63 mg/mL to 2.50 mg/mL. In time-kill curve, L. monocytogenes and P. aeruginosa were found completely killed after exposing to extract in 1 h incubation at 4x MIC. Four hours had been taken to completely kill E. coli, S. aureus, V. cholerae, and V. parahaemolyticus at 4x MIC. However, the population of K. pneumoniae, P. mirabilis, and S. typhimurium only reduced to 3 log CFU/mL. The treated cell showed cell rupture and leakage of the cell cytoplasm in SEM observation. The significant reduction of natural microflora in grapes fruit was started at 0.50% of extract at 5 min and this concentration also was parallel to sensory attributes acceptability where application of extract was accepted by the panellists until 5%. In conclusion, S. polyanthum extract exhibits antimicrobial activities and thus might be developed as natural sanitizer for washing raw food materials.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Etanol/química , Microbiología de Alimentos , Extractos Vegetales/farmacología , Hojas de la Planta/química , Syzygium/química , Bacterias/ultraestructura , Pruebas de Sensibilidad Microbiana , Factores de Tiempo , Vitis/efectos de los fármacosRESUMEN
AIM: Study the topographic features of dentin after caries removal with a chemomechanical agent (Papacarie) compared with the conventional drilling method. STUDY DESIGN: The sample included 7 exfoliated and extracted primary teeth with carious dentin lesions, not reaching the pulp. Each tooth was sectioned longitudinally through the center of the carious lesions into two halves. The teeth were then divided into two groups according to the method of caries removal. Following caries removal, dentin topography and the cut section were examined using the scanning electron microscope. RESULTS: Papacarie produced an irregular, porous, rough and globular dentin appearance. The dentin surfaces were generally free of smear layer, visible bacteria and the dentinal tubules were opened. The dentin cut surfaces showed patent dentinal tubules with open orifices. The drilling method created a smooth and amorphous surface with a continuous smear layer occluding the dentinal tubules. Numerous bacteria were also observed. The cut dentin surfaces showed patent dentinal tubules with their orifices plugged with smear layer. CONCLUSIONS: Papacarie produced a rough and porous surface with partial or complete removal of the smear layer and opened dentinal tubules, while the drill produced a smooth surface with uniform smear layer occluding the dentinal tubules.
Asunto(s)
Preparación de la Cavidad Dental/métodos , Dentina/ultraestructura , Papaína/uso terapéutico , Diente Primario/ultraestructura , Bacterias/ultraestructura , Colágeno/ultraestructura , Caries Dental/microbiología , Caries Dental/patología , Caries Dental/terapia , Preparación de la Cavidad Dental/instrumentación , Equipo Dental de Alta Velocidad , Dentina/efectos de los fármacos , Dentina/microbiología , Humanos , Microscopía Electrónica de Rastreo , Porosidad , Capa de Barro Dentinario/patología , Diente Primario/efectos de los fármacos , Diente Primario/microbiologíaRESUMEN
ABSTRACT Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material.
Asunto(s)
Bacterias/clasificación , Petróleo/microbiología , Biodiversidad , Microbiología Ambiental , Filogenia , Bacterias/genética , Bacterias/ultraestructura , ARN Ribosómico 16S/genéticaRESUMEN
Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material.
Asunto(s)
Bacterias/clasificación , Biodiversidad , Microbiología Ambiental , Petróleo/microbiología , Bacterias/genética , Bacterias/ultraestructura , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.
Asunto(s)
Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Bioprospección/métodos , Descubrimiento de Drogas/métodos , Hongos/efectos de los fármacos , Fitoquímicos/farmacología , Extractos Vegetales/farmacología , Antiinfecciosos/aislamiento & purificación , Bacterias/ultraestructura , Hongos/ultraestructura , Microscopía Electrónica de Rastreo , Fitoquímicos/aislamiento & purificación , Fitoterapia , Extractos Vegetales/aislamiento & purificación , Plantas MedicinalesRESUMEN
BACKGROUND: The growing threat of microbial resistance against traditional antibiotics has prompted the development of several antimicrobial nanoparticles (NPs), including silver NPs (AgNPs). In this article, a simple and eco-friendly method for the synthesis of AgNPs using the cranberry powder aqueous extract is reported. MATERIALS AND METHODS: Cranberry powder aqueous extracts (0.2%, 0.5%, and 0.8% w/v) were allowed to interact for 24 hours with a silver nitrate solution (10 mM) at 30°C at a ratio of 1:10. The formation of AgNPs was confirmed by ultraviolet-visible spectroscopy and their concentrations were determined using atomic absorption spectroscopy. The prepared NPs were evaluated by transmission electron microscopy, measurement of ζ-potential, and Fourier-transform infrared spectroscopy. The in vitro antimicrobial properties of AgNPs were then investigated against several microbial strains. Finally, in vivo appraisal of both wound-healing and antimicrobial properties of either plain AgNPs (prepared using 0.2% extract) or AgNP-Pluronic F-127 gel was conducted in a rat model after induction of a Staphylococcus aureus ATCC 6538P wound infection. RESULTS: The formation of AgNPs was confirmed by ultraviolet-visible spectroscopy, where a surface-plasmon resonance absorption peak was observed between 432 and 438 nm. Both size and concentration of the formed AgNPs increased with increasing concentration of the extracts. The developed NPs were stable, almost spherical, and polydisperse, with a size range of 1.4-8.6 nm. The negative ζ-potential values, as well as Fourier-transform infrared spectroscopy analysis, indicated the presence of a capping agent adsorbed onto the surface of the particles. In vitro antimicrobial evaluation revealed a size-dependent activity of the AgNPs against the tested organisms. Finally, AgNPs prepared using 0.2% extract exhibited a substantial in vivo healing potential for full-thickness excision wounds in rats. CONCLUSION: AgNPs were successfully synthesized from a silver nitrate solution through a simple green route, using cranberry powder aqueous extract as a reducing as well as capping agent.
Asunto(s)
Antiinfecciosos/farmacología , Tecnología Química Verde/métodos , Nanopartículas del Metal/química , Extractos Vegetales/farmacología , Plata/química , Vaccinium macrocarpon/química , Animales , Bacterias/efectos de los fármacos , Bacterias/ultraestructura , Geles/farmacología , Masculino , Nanopartículas del Metal/ultraestructura , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Extractos Vegetales/química , Poloxámero/farmacología , Polvos , Ratas , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Cicatrización de Heridas/efectos de los fármacosRESUMEN
Bacterial cells often contain dense granules. Among these, polyphosphate bodies (PPBs) store inorganic phosphate for a variety of essential functions. Identification of PPBs has until now been accomplished by analytical methods that required drying or chemically fixing the cells. These methods entail large electron doses that are incompatible with low-dose imaging of cryogenic specimens. We show here that Scanning Transmission Electron Microscopy (STEM) of fully hydrated, intact, vitrified bacteria provides a simple means for mapping of phosphorus-containing dense granules based on quantitative sensitivity of the electron scattering to atomic number. A coarse resolution of the scattering angles distinguishes phosphorus from the abundant lighter atoms: carbon, nitrogen and oxygen. The theoretical basis is similar to Z contrast of materials science. EDX provides a positive identification of phosphorus, but importantly, the method need not involve a more severe electron dose than that required for imaging. The approach should prove useful in general for mapping of heavy elements in cryopreserved specimens when the element identity is known from the biological context.
Asunto(s)
Bacterias/química , Bacterias/ultraestructura , Gránulos Citoplasmáticos/ultraestructura , Microscopía Electrónica de Transmisión de Rastreo/métodos , Fósforo/análisis , Vitrificación , Carbono/análisis , Microscopía por Crioelectrón/instrumentación , Microscopía por Crioelectrón/métodos , Gránulos Citoplasmáticos/química , Electrones , Nitrógeno/análisis , Oxígeno/análisis , PolifosfatosRESUMEN
Inhalation therapy using essential oils has been used to treat acute and chronic sinusitis and bronchitis. The aim of the present study was to determine the chemical composition of the essential oil of Artemisia capillaris, and evaluate the antibacterial effects of the essential oil and its main components, against common clinically relevant respiratory bacterial pathogens. Gas chromatography and gas chromatographymass spectrometry revealed the presence of 25 chemical constituents, the main constituents being: αpinene, ßpinene, limonene, 1,8cineole, piperitone, ßcaryophyllene and capillin. The antibacterial activities of the essential oil, and its major constituents, were evaluated against Streptococcus pyogenes, methicillinresistant Staphylococcus aureus (MRSA), MRSA (clinical strain), methicillingentamicin resistant Staphylococcus aureus (MGRSA), Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae and Escherichia coli. The essential oil and its constituents exhibited a broad spectrum and variable degree of antibacterial activity against the various strains. The essential oil was observed to be much more potent, as compared with any of its major chemical constituents, exhibiting low minimum inhibitory and bacteriocidal concentration values against all of the bacterial strains. The essential oil was most active against S. pyogenes, MRSA (clinical strain), S. pneumoniae, K. pneumoniae, H. influenzae and E. coli. Piperitone and capillin were the most potent growth inhibitors, among the major chemical constituents. Furthermore, the essential oil of A. capillaris induced significant and dosedependent morphological changes in the S. aureus bacterial strain, killing >90% of the bacteria when administered at a higher dose; as determined by scanning electron microscopy. In addition, the essential oil induced a significant leakage of potassium and phosphate ions from the S. aureus bacterial cultures. These results indicate that the antibacterial action of A. capillaris essential oil may be mediated through the leakage of these two important ions. In conclusion, A. capillaris essential oil exhibits potent antibacterial activity by inducing morphological changes and leakage of ions in S. aureus bacterial cultures.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Artemisia/química , Bacterias/efectos de los fármacos , Aceites Volátiles/química , Aceites Volátiles/farmacología , Bacterias/metabolismo , Bacterias/ultraestructura , Cromatografía de Gases y Espectrometría de Masas , Humanos , Pruebas de Sensibilidad Microbiana , Fosfatos/metabolismo , Potasio/metabolismo , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Infecciones del Sistema Respiratorio/microbiologíaRESUMEN
This work describes the performance and microbial diversity in a sequencing batch reactor of a decentralized full-scale system for urban wastewater treatment under limited aeration. The removal efficiency was: 83% for soluble chemical oxygen demand (SCOD), 60% for N-NH4(+), 70% for total suspended solids (TSS) and 80% for volatile suspended solids (VSS). The biomass concentration had a maximum value around 8.7gVSSL(-1) for organic load rate of 0.6gCODL(-1)d(-1). The food/microorganism ratios showed average of 0.2gCOD/gVSSd. The sludge bacterial flocs were formed an irregular arrangement with organisms attached such as Euglypha sp. and pedunculate ciliates. It was observed the presence of Bacteria domains including Nitrosomonas spp., Nitrobacter spp., Nitrospira and C. "Accumulibacter" cluster. The DPAO activity was 70%. Denaturing gradient gel electrophoresis showed changes in ribotype number over biological treatment time among the groups observed being some are linked to nutrient removal. The reactor showed viability to treat domestic wastewater.
Asunto(s)
Bacterias/metabolismo , Biodiversidad , Reactores Biológicos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Bacterias/genética , Bacterias/ultraestructura , Análisis de la Demanda Biológica de Oxígeno , Biomasa , Brasil , ADN Ribosómico/genética , Electroforesis en Gel de Gradiente Desnaturalizante , Floculación , Hibridación Fluorescente in Situ , Microscopía Electrónica de Rastreo , Fósforo/metabolismo , Especificidad de la EspecieRESUMEN
Understanding the relationship between microbial community and mechanism of aerobic granulation could enable wider applications of granules for high-strength wastewater treatment. The majority of granulation studies principally determine the engineering aspects of granules formation with little emphasis on the microbial diversity. In this study, three identical reactors namely R1, R2 and R3 were operated using POME at volumetric loadings of 1.5, 2.5 and 3.5 kg COD m(-3) d(-1), respectively. Aeration was provided at a volumetric flow rate of 2.5 cms(-1). Aerobic granules were successfully developed in R2 and R3 while bioflocs dominated R1 until the end of experiments. Fractal dimension (D(f)) averaged at 1.90 suggesting good compactness of granules. The PCR-DGGE results indicated microbial evolutionary shift throughout granulation despite different operating OLRs based on decreased Raup and Crick similarity indices upon mature granule formation. The characteristics of aerobic granules treating high strength agro-based wastewater are determined at different volumetric loadings.
Asunto(s)
Bacterias/metabolismo , Reactores Biológicos , Aceites de Plantas/química , Aguas del Alcantarillado/microbiología , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/análisis , Aerobiosis , Agricultura , Bacterias/genética , Bacterias/ultraestructura , Análisis de la Demanda Biológica de Oxígeno , Colorimetría , Cartilla de ADN/genética , Electroforesis en Gel de Gradiente Desnaturalizante , Fractales , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Aceite de Palma , Reacción en Cadena de la PolimerasaRESUMEN
An integrated fluidized bed reactor (FBR) has been employed as the treatment for petrochemical industry wastewaters with high organic matter and aromatic compounds, under anaerobic and aerobic conditions. The system was operated at hydraulic residence time (HRT) of 2.7 and 2.2 h in the anaerobic and aerobic reactor, respectively. The degree of fluidization in the beds was 30%. This system showed a high performance on the removal of organic matter and aromatic compounds. At different organic loading rates (OLR), the chemical oxygen demand (COD) removal in the anaerobic reactor was close to 85% and removals of the COD up to 94% were obtained in the aerobic reactor. High removals of benzene, toluene, ethylbenzene, xylenes, styrene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and naphthalene were achieved in this study.
Asunto(s)
Reactores Biológicos/microbiología , Hidrocarburos Aromáticos/aislamiento & purificación , Petróleo/análisis , Aguas Residuales/química , Purificación del Agua/instrumentación , Purificación del Agua/métodos , Aerobiosis , Anaerobiosis , Bacterias/ultraestructura , Adhesión Bacteriana , Biodegradación Ambiental , Biopelículas/crecimiento & desarrollo , Análisis de la Demanda Biológica de Oxígeno , Metano/análisis , Oxígeno/análisis , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
The feasibility of using an indigenous microbial consortium for the removal of crude oil from an oil-spilled coastal area was explored with the ultimate aim of applying for bioremediation. Initially, we obtained the microbial consortium TK-2 that catalyzed the dispersion as well as the degradation of crude oil in supplemented sea water. GC and GC-MS were used to evaluate the removal patterns of crude oil during the incubation. The effective removal of crude oil by TK-2 occurred, and above 95% of all aliphatic and aromatic compounds detected in this work was removed within 30 days of incubation. Two predominant crude oil-grown isolates derived from TK-2 revealed gram-negative, rod-shaped cells. Both BIOLOG system and 16S rRNA sequencing were conducted to identify the strains, which were assigned to Arthrobacter sp. HK-2 and Pseudoalteromonas sp. HK-3, and registered in GenBank as [FJ477042] and [FJ477041].
Asunto(s)
Biodegradación Ambiental , Contaminación por Petróleo , Bacterias/genética , Bacterias/metabolismo , Bacterias/ultraestructura , Secuencia de Bases , Biocatálisis , Cartilla de ADN , Cromatografía de Gases y Espectrometría de Masas , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Petróleo , Reacción en Cadena de la Polimerasa , República de CoreaRESUMEN
Crustaceans form a variety of calcium deposits in which they store calcium necessary for the mineralization of their exoskeletons. Calcium bodies, organs containing large amounts of calcium, have been reported in some terrestrial isopod crustaceans, but have not yet been extensively studied. We analyzed the architecture of these organs during the molt cycle in the isopod Titanethes albus. Two pairs of calcium bodies are positioned ventrolaterally in posterior pereonites of T. albus. Individual organs are epithelial sacs that contain material arranged in concentric layers delimited by thin laminae. As demonstrated by electron microscopy and fluorescence in situ hybridization, abundant bacteria are present within the calcium bodies. Regardless of the molt cycle stage, crystalline concretions are present in the central areas of the calcium bodies. Energy dispersive X-ray spectrometry of the concretions demonstrated that they are composed predominantly of calcium and phosphorus and selected area electron diffraction indicated the presence of hydroxyapatite. In molting animals, a glassy layer of mineralized matrix is formed between the envelope and the outermost lamina of the calcium body. This layer consists of an amorphous calcium mineral which contains less phosphorus than the central concretions and is resorbed after molt. Since changes in the mineralized matrix are synchronized with the molt cycle, the calcium bodies likely function as a storage compartment that complements sternal deposits as a source of calcium for the mineralization of the exoskeleton. Bacteria associated with the mineralized matrix of calcium bodies are evidently involved in calcium dynamics.