RESUMO
Providing clean drinking water is a great challenge worldwide, especially for low-income countries where the access to safe water is limited. During the last decade, new biotechnological approaches have been explored to improve water management. Among them, the use of antimicrobial nanoparticles for designing innovative centralized and decentralized (point-of-use) water treatment systems for microbial decontamination has received considerable attention. Herein, antimicrobial lignin capped silver nanoparticles (AgLNP) were embedded on residual cork pieces using high-intensity ultrasound coupled with laccase-mediated grafting to obtain biofunctionalized nanomaterial. The developed AgLNP-coated cork proved to be highly efficient to drastically reduce the number of viable Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus in liquid medium. Additionally, the coated-cork was characterized using FTIR-ATR spectroscopy and SEM imaging, and further used as a filter bed in a point-of-use device for water disinfection. The constructed water filtering system significantly reduced the amount of viable E. coli and resistant Bacillus cereus spores from filtered water operating at increasing residence times of 1, 4, 6, 16, 24, and 48 h. Therefore, the presented results prove that the obtained cork-based antimicrobial nanocomposite material could be used as a filtering medium for the development of water filtration system to control pathogen dissemination.
Assuntos
Anti-Infecciosos , Água Potável , Nanopartículas Metálicas , Purificação da Água , Antibacterianos/química , Antibacterianos/farmacologia , Desinfecção/métodos , Escherichia coli , Lacase , Lignina , Nanopartículas Metálicas/química , Prata/química , Prata/farmacologia , Purificação da Água/métodosRESUMO
In this work, we have evaluated the impact of intermittent induced aeration in total nitrogen (TN), ammonia (NH4-N) and nitrate-nitrogen (NO3-N) removal in four pilot-scale vertical flow constructed wetlands (VFCW) (two aerated two non-aerated) using cork by-product or gravel as the filter material and planted with Phragmites australis. Both aerated and non-aerated systems achieved high COD and BOD5 elimination rates (≥ 90%) at the end of the 5-month test period. However, the aerated systems presented maximal COD and BOD5 removal from the third month of operation onwards since air supply favored the oxidative bioprocesses occurring within the wetlands. Cork and gravel aerated VFCW also proved to be more efficient (p < 0.05) in NO3-N removal than the non-aerated systems and this upgraded performance was correlated with a significant higher relative abundance of the nirS gene. The aerated systems also showed a slightly improved NH4-N removal. Noticeably, cork VFCW showed higher TN removal mean values (â¼35%) than gravel wetlands (27-28%) regardless aeration. Moreover, cork VFCW showed higher relative abundance of the nosZ gene. Our results demonstrated a better nitrogen elimination for the aerated cork pilot-scale VFCW, and this behavior was correlated with a higher abundance of both nirS and nosZ, two of the key functional genes involved in nitrogen metabolism.
Assuntos
Nitrogênio , Áreas Alagadas , Análise da Demanda Biológica de Oxigênio , Desnitrificação , Nitratos , Nitrogênio/análise , Eliminação de Resíduos LíquidosRESUMO
The main goal of the present study was to enhance the rhizobacterium potential in a horizontal subsurface flow constructed wetland system planted with Phragmites australis, through environmentally friendly biological approaches. The bioinoculation of antagonist bacteria has been used to promote higher rhizosphere competence and improve pathogenic bacteria removal from wastewater. The experiment was performed both with single and sequential bioinoculation. The results showed that strain PFH1 played an active role in pathogenic bacteria removal, remarkably improving inactivation kinetics of the pathogenic tested bacterium Salmonella typhi in the plant rhizosphere. The single bioinoculation of selected bacteria into the rhizosphere of P. australis improved the kinetics of S. typhi inactivation by approximately 1 U-Log10 (N/N0) (N is the number of viable cultured bacteria at time t, N0 is the number of viable and cultivable bacteria at time t0) compared to the control. By a series of multi-bioinoculations, the enhancement of pathogenic bacteria reduction compared to the inhibition rate in the pilot-scale control was of 2 U-Log10(N/N0). These findings suggested that this strain represents a promising candidate to enhance water purification in constructed wetlands.
Assuntos
Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/microbiologia , Microbiologia da Água , Áreas Alagadas , Bactérias , Rizosfera , Purificação da ÁguaRESUMO
Helicobacter pylori infection is a risk factor for chronic active gastritis, peptic ulcers, gastric carcinoma and lymphoma. Although the infection may be acquired through different transmission routes, the presence and viability of H. pylori in water sources are not well known. Therefore, the aim of our study was to analyse the viability of H. pylori cells in urban surface waters collected at the Vallparadís public park in Terrassa, Barcelona, Spain. The water samples were analysed by viability quantitative polymerase chain reaction (qPCR) using propidium monoazide and specific primers for the H. pylori vacuolating cytotoxin (vacA gene). Viable H. pylori were found in 91.3% of the samples analysed, with an average concentration of 3.46 ± 1.06 log cell 100 mL-1. Our work proves a quick and simple procedure for evaluating viable H. pylori cells in environmental samples by qPCR. Furthermore, the results provide evidence that urban surface waters may contain considerable levels of viable H. pylori cells, thus indicating they are a potential source of infection, which represents a public health concern.
Assuntos
Monitoramento Ambiental , Helicobacter pylori/crescimento & desenvolvimento , Microbiologia da Água , Antígenos de Bactérias , Proteínas de Bactérias , Infecções por Helicobacter , Humanos , EspanhaRESUMO
Propidium monoazide (PMA) or ethidium bromide monoazide (EMA) treatment has been used before nucleic acid detection methods, such as PCR, to distinguish between live and dead cells using membrane integrity as viability criterion. The performance of these DNA intercalating dyes was compared in many studies utilizing different microorganisms. These studies demonstrated that EMA and PMA differ in their abilities to identify nonviable cells from mixed cell populations, depending on the microorganism and the nature of the sample. Due to this heterogeneity, both dyes were used in the present study to specifically distinguish dead from live Candida albicans cells using viable quantitative PCR (qPCR). The viable qPCR was optimized, and the best results were obtained when pre-treating the cells for 10 min in the dark with 25 µM EMA followed by continuous photoactivation for 15 min. The suitability of this technique to distinguish clotrimazole- and fluconazole-treated C. albicans cells from untreated cells was then assessed. Furthermore, the antifungal properties of two commercial essential oils (Thymus vulgaris and Matricaria chamomilla) were evaluated. The viable qPCR method was determined to be a feasible technique for assessing the viability of C. albicans after drug treatment and may help to provide a rapid diagnostic and susceptibility testing method for fungal infections, especially for patients treated with antifungal therapies.
Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Contagem de Colônia Microbiana/métodos , Viabilidade Microbiana/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Azidas/metabolismo , Candida albicans/genética , Candida albicans/fisiologia , Clotrimazol/farmacologia , Fluconazol/farmacologia , Matricaria/química , Óleos Voláteis/farmacologia , Thymus (Planta)/químicaRESUMO
This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.
Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes/efeitos dos fármacos , Carbono/metabolismo , Fungicidas Industriais/metabolismo , Nitrilas/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Cromatografia Gasosa , Monitoramento Ambiental , Compostos Orgânicos/metabolismo , Projetos Piloto , Poaceae/crescimento & desenvolvimento , Áreas AlagadasRESUMO
The progressive aging and comorbidities of the population have led to an increase in the number of patients with polypharmacy attended to in the emergency department. Drug-related problems (DRPs) have become a major cause of admission to these units, as well as a high rate of short-term readmissions. Anticoagulants, antibiotics, antidiabetics, and opioids have been shown to be the most common drugs involved in this issue. Inappropriate polypharmacy has been pointed out as one of the major causes of these emergency visits. Different ways of conducting chronic medication reviews at discharge, primary care coordination, and phone contact with patients at discharge have been shown to reduce new hospitalizations and new emergency room visits due to DRPs, and they are key elements for improving the quality of care provided by emergency services.
RESUMO
Greenhouse gases emissions resulting from the combustion of fossil fuels are worsening air quality and affecting the climate system. While climate change impacts on meteorological variables affects air quality by altering the concentration and distribution of pollutants, air pollution significantly influences the climate, leading to negative impacts on human health. Due to the combination of high temperatures, air pollution, and high population density, cities are particularly vulnerable to climate change impacts. The planning and design of public spaces aimed at climate change mitigation and adaptation can result in multiple co-benefits for human health, while reducing social inequalities. To address the major research gaps in the communication between health and planning experts, and the lack of capacity among public sectors and policy makers, it is necessary to promote capacity building and knowledge sharing between the planning and health sectors. The purpose of this article is to develop preliminary recommendations for a process that allows a comprehensive assessment of the interlinkages between climate and health, social, environmental, and economic vulnerabilities, and the quality of the urban spaces, to support local governments, policymakers, and education institutions in making informed decisions for public spaces. The methods applied were a literature review and interviews with experts.
Assuntos
Poluição do Ar , Gases de Efeito Estufa , Poluição do Ar/análise , Cidades , Mudança Climática , Combustíveis Fósseis , Humanos , Saúde PúblicaRESUMO
This study investigated the spatial distribution of clogging matter in a full-scale horizontal subsurface flow treatment wetland (HSSF TW) based on an electrical resistivity tomography (ERT) method, comparing the performance of two different electrode configurations (i.e., Schlumberger and Wenner arrays). The results indicated that during the draining phase, the substrate apparent resistivities of the full-scale HSSF TWs were negatively correlated with the clogging matter fraction (v/v), and a functional relationship between the two parameters was established using a first-order k-C* model. The detected clogging matter fraction (v/v) based on the Schlumberger array showed higher accuracy (linear slope = 0.900, R-squared = 0.902) than the Wenner array (linear slope = 0.685, R-squared = 0.685). Most of the severe substrate clogging in the full-scale HSSF TW occurred within a 10-m flow distance, and the distribution of the clogging matter showed different characteristics at different substrate depths. From a cross section positioned 1 m from the inlet, the average clogging matter fraction (v/v) at a 0-0.30 m depth (23.1 ± 14.9%) was significantly higher than that at a 0.30-0.80 m depth (5.0 ± 2.1%). The clogging matter at a 5-m flow distance was evenly distributed at different substrate depths. Only a few localized clogging zones were observed in the cross section at a 10-m flow distance. This study provided an accurate and feasible method for investigating the volume fraction of clogging matters containing different organic contents and demonstrates the spatial heterogeneity of clogging matter in HSSF TWs.
Assuntos
Eliminação de Resíduos Líquidos , Áreas Alagadas , Eletricidade , Eletrodos , Tomografia , Eliminação de Resíduos Líquidos/métodosRESUMO
Even though the advent of quantitative polymerase chain reaction (PCR) has improved the detection of pathogen microorganisms in most of areas of microbiology, a serious limitation of this method may arise from the inability to discriminate between viable and nonviable pathogens. To overcome it, the use of real-time PCR and selective nucleic acid intercalating dyes like propidium monoazide (PMA) have been effectively evaluated for different microorganisms. To assess whether PMA pretreatment can inhibit PCR amplification of nonviable amoeba DNA, Acanthamoeba castellani survival was measured using cell culture and real-time PCR with and without PMA pretreatment. Autoclave and contact lens disinfecting solutions were used to inactivate amoebae. After these inactivation treatments, the results indicated that the PMA pretreatment approach is appropriate for differentiating viable A. castellani, both trophozoites and cysts. Therefore, the PMA-PCR approach could be useful as a rapid and sensitive analytical tool for monitoring treatment and disease control, assessing effective disinfection treatments, and for a more reliable understanding of the factors that contribute to the interaction amoeba-pathogenic bacteria.
Assuntos
Acanthamoeba castellanii/citologia , Acanthamoeba castellanii/fisiologia , Azidas , Reação em Cadeia da Polimerase/métodos , Propídio/análogos & derivados , Trofozoítos/citologia , Acanthamoeba castellanii/genética , Acanthamoeba castellanii/isolamento & purificação , Soluções para Lentes de Contato , DNA de Protozoário/análise , DNA de Protozoário/genética , Coloração e Rotulagem , Trofozoítos/fisiologiaRESUMO
Selective nucleic acid intercalating dyes--ethidium monoazide (EMA) and propidium monoazide (PMA)--represent one of the most successful recent approaches to detect viable cells (as defined by an intact cell membrane) by PCR and have been effectively evaluated in different microorganisms. However, some practical limitations were found, especially in environmental samples. The aim of this work was to show that in the application of viable real-time PCR, there may be significant biases and to propose a strategy for overcoming some of these problems. We present an approach based on the combination of three real-time PCR amplifications for each sample that should provide an improved estimation of the number of viable cells. This approach could be useful especially when it is difficult to determine a priori how to optimize methods using PMA or EMA. Although further studies are required to improve viable real-time PCR methods, the concept as outlined here presents an interesting future research direction.
Assuntos
Carga Bacteriana/métodos , Microbiologia Ambiental , Viabilidade Microbiana , Reação em Cadeia da Polimerase/métodos , Legionella pneumophila/genética , Legionella pneumophila/fisiologia , Sensibilidade e EspecificidadeRESUMO
There is an increasing level of interest in non-tuberculous mycobacteria (NTM) due to the increasing reported rates of diseases caused by them. Although it is well known that NTM are widely distributed in the environment it is necessary to identify its reservoirs to prevent possible infections. In this study, we aimed to investigate the occurrence and levels of NTM in cooling towers to provide evidences for considering these settings as possible sources of respiratory infections. In the current study, we detected and quantified the presence of NTM by means of a rapid method in water samples taken from 53 cooling towers of an urban area (Barcelona, Spain). A genus-specific quantitative PCR (Q-PCR) assay with a quantification limit (QL) of 500 cells l(-1) was used. 56% (30) of samples were positive with a concentration range from 4.6 × 10(3) to 1.79 × 10(6) cells l(-1). In some cases (9/30), samples were positive but with levels below the QL. The colonization rate confirmed that cooling towers could be considered as a potential reservoir for NTM. This study also evaluated Q-PCR as a useful method to detect and quantify NTM in samples coming from environmental sources.
Assuntos
Carga Bacteriana/métodos , Mycobacterium/classificação , Mycobacterium/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Microbiologia da Água , Humanos , Mycobacterium/genética , Prevalência , Estudos Prospectivos , EspanhaRESUMO
Simkania negevensis is an obligate intracellular bacterium grouped into the order Chlamydiales. This new amoeba-resistant intracellular bacterium might represent a novel etiologic agent of bronchiolitis and community-acquired pneumonia and occurs in aquatic habitats such as drinking water and reclaimed wastewater. Another amoeba-related bacterium, Legionella pneumophila, is an etiologic agent of pneumonia transmitted by environmental aerosols or contaminated water/air cooling systems. These transmission pathways are important in the natural history of Legionellae infections and possibly other intracellular microorganisms such as Parachlamydiaceae; thus, understanding the feasibility of Simkania infection by these routes is relevant. In the present work, we investigated the prevalence of this newly identified pathogenic bacterium in cooling towers by quantitative PCR (qPCR) and its possible relationship with Legionella pneumophila co-infection. Our results show Simkania detection in 2 of 70 cooling towers analyzed. To our knowledge, this report is the first describing Simkania negevensis detection in this category of environmental water samples.
Assuntos
Chlamydiales/isolamento & purificação , Microbiologia da Água , Ar Condicionado , Contagem de Colônia Microbiana , Doenças Transmissíveis Emergentes/microbiologia , Indústrias , Legionella pneumophila/isolamento & purificação , Reação em Cadeia da Polimerase , Prevalência , EspanhaRESUMO
BACKGROUND: Our objective was to assess in non-critically-ill adult inpatients receiving parenteral nutrition (PN) the risk of developing liver function test (LFT) alterations when receiving concomitant possibly hepatotoxic medications or others reported to improve LFTs during PN. METHODS: A multicenter retrospective analysis of prospectively collected data was performed on patients receiving PN. Two groups were recruited: group LALT (patients with any LFT alterations during PN), and group NOLALT (patients without such alterations). Exclusion criteria were previous sepsis, shock, renal failure, hyperglycemia, LFT alteration, or biliopancreatic surgical procedures. Medications were classified into 2 categories: medications reported to improve LFTs during PN (n = 8) and possibly hepatotoxic medications (n = 54), including a subgroup of possibly highly hepatotoxic medications (n = 30). RESULTS: The study included 200 patients, 136 (68.0%) in the LALT group. The groups differed in the number of patients requiring surgical intervention ≤7 days before PN (LALT, 94 [69.1%]; NOLALT, 29 [45.3%]; P < .002) and those receiving possibly hepatotoxic medications (LALT, 126 [92.6%]; NOLALT, 45 [70.3%]; P < .001). Variables in the final Cox regression model were possibly hepatotoxic medications, odds ratio (OR) 3.310 (1.678-6.530); surgical intervention prior to PN, OR 1.861 (1.277-2.711); baseline triglyceridemia, OR 1.005 (1.001-1.009); and creatinine, OR 1.861 (1.043-3.323). CONCLUSIONS: Patients who received PN and concomitantly possibly hepatotoxic medications had a 3-fold risk of developing LFT alterations. Medications reported to improve LFTs had no effect. The use of possibly hepatotoxic medications during PN was associated with LFT alterations.
Assuntos
Nutrição Parenteral Total , Nutrição Parenteral , Adulto , Estudos de Coortes , Humanos , Testes de Função Hepática , Nutrição Parenteral/efeitos adversos , Estudos RetrospectivosRESUMO
BACKGROUND: While Helicobacter pylori exists in a bacillary form in both the natural habitat and the human host, detrimental environmental circumstances have been observed to lead to the conversion of H. pylori from the bacillary to the coccoid form. However, the viability or nonviability of coccoid forms remains to be established in H. pylori. The aim of this study was to determine whether the quantitative PCR combined with propidium monoazide could be an alternative and good technique to determine H. pylori viability in environmental samples and, to contribute to understanding of the role of the H. pylori forms. MATERIALS AND METHODS: Viability, morphological distribution, and the number of live H. pylori cells were determined using a propidium monoazide-based quantitative PCR method, at various time points. RESULTS: Under adverse environmental conditions was observed the conversion of H. pylori from the bacillary to the coccoid form, and the decrease in amplification signal, in samples that were treated with propidium monoazide, over the time. CONCLUSIONS: Incorporation of propidium monoazide indicates that there is an increase in H. pylori cells with the damaged membrane over the study, leading to the manifestation of cellular degeneration and death. Consequently, quantitative PCR combined with propidium monoazide contributes to our understanding of the role of H. pylori cells, under adverse environmental conditions.
Assuntos
Azidas/metabolismo , Técnicas Bacteriológicas/métodos , Microbiologia Ambiental , Helicobacter pylori/fisiologia , Viabilidade Microbiana , Reação em Cadeia da Polimerase/métodos , Propídio/análogos & derivados , Inibidores Enzimáticos/metabolismo , Helicobacter pylori/citologia , Helicobacter pylori/genética , Humanos , Microscopia , Propídio/metabolismoRESUMO
Agricultural practices have raised the level of nutrients reaching aquifers. In Europe, nitrate pollution is considered as one of the main threats for the quality of groundwater in agricultural areas. Treatment wetlands (TWs), also known as Constructed Wetlands, are used for groundwater treatment in areas with an important concentration of nitrogen compounds; total nitrogen removal depends on the type and operation scheme. Cork by-product from the industry has shown clear adsorbent properties to remove organic pollutants. The work is focused on the characterization of microbial communities involved in the nitratenitrogen removal process in groundwater polluted from agricultural activities. The experimental design allowed the comparison of nitrate removal efficiency depending on the filter media material, cork by-product or gravel, used in two hybrid TWs (a vertical flow cell followed by a horizontal subsurface flow cell), installed in areas close to two irrigated agricultural plots at the Lleida plain area (Spain). Both physicochemical and microbial results were consistent and confirm the nitrate removal efficiency using cork as a filter media. A significant (pâ¯=â¯0.0025) higher removal in Bellvís TW using cork compared with the Vilanova de la Barca gravel system was observed, achieving a removal rate from 80 to 99% compared to the 5-46%, respectively. Regarding the community composition of the two different TWs, microorganisms were mainly related to the phylum Proteobacteria, and included members found to be key players in the nitrogen cycle, such as ammonia and nitrite oxidizers, as well as denitrifiers. Also, the group Bacteroidetes turns to be another abundant phylum from our bacterial dataset, whose members are suggested to be strongly involved in denitrification processes. Some groups showed to prevail depending on the type of media (cork or gravel); Firmicutes and Delta and Epsilonproteobacteria had a significant higher abundance in the TW with cork, while Acidobacteria and Planctomyces were prevalent in gravel. Therefore, cork could be an alternative material used by treatment wetlands to minimize the impact in the environment caused by nitrogen pollution in groundwater bodies.
Assuntos
Água Subterrânea/química , Microbiota/fisiologia , Nitratos/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Áreas Alagadas , Adsorção , Agricultura , Materiais de Construção/análise , Filtração , Casca de Planta/química , Proteobactérias/isolamento & purificação , Quercus/química , EspanhaRESUMO
Reusing by-products is an important strategy to ensure the preservation of natural capital and climate change mitigation. This study aimed at evaluating the potential of cork granulates, a by-product of winery industry, as an organic carbon (OC) source for the treatment of hydroponic wastewaters. First, chemical characterization was performed and discussed. Secondly, batch studies were performed using synthetic hydroponic wastewater to understand the role of particle size (PS), pH and contact time (CT) on the release of OC. The suberin is the major compound, representing >50%. It was noticed that a variance on the content of suberin across species, within the same species and depending on the extraction part (belly, cork and back) could be expected. >60% of the sample is composed by carbon while <1% was nitrogen (high C:N ratio), indicating a low risk of releasing organic nitrogen. The statistical results suggested that the main effect of PS on the release of OC is greater than both, CT and pH. The chemical release of OC gets slower with time, being this effect greater as the PS increase. Moreover, estimations showed that using the 4â¯mm PS, the amount of water treated would be twice the amount if the 8â¯mm PS had been used. The PS seems to play an important role at design nature-based solutions (NBS) focused on denitrification. The surface response methodology indicates a significant negative interaction between CT and PS suggesting that the mathematical model could be used for further optimization studies. The reuse of organic by-products as filter media seems to be an economic and environmentally friendly alternative to enhance denitrification in NBS, while preserving natural capital. However, further real scale and long-term experiments are needed to validate cork's potential as an "internal" OC source for NBS.
RESUMO
Amphiphilic ionic complexes of hyaluronic acid and alkyltrimethylphosphonium soaps with alkyl chains containing even numbers of carbons from 12 to 22 have been produced. The complexes have a nearly stoichiometric composition, are non-water soluble, and are stable to heat up to temperatures above 200⯰C. These complexes are amphiphilic and able to adopt a biphasic structure with the paraffinic and polysaccharide phases ordered arranged with a periodicity ranging between 3 and 5â¯nm depending on n. The paraffinic phase in complexes with nâ¯≥â¯18 was crystallized and showed melting at temperatures between 58 and 70⯰C depending on the n value. The complexes decomposed upon incubation in water under physiological conditions, and undergone extensive biodegradation by the action of hyaluronidases. Biocide assays carried out in both solid and liquid media demonstrated a high antimicrobial activity of the complexes against Gram-positive S. aureus but moderate against Gram-negative E. coli and C. albicans fungi.
Assuntos
Anti-Infecciosos/farmacologia , Ácido Hialurônico/química , Compostos Organofosforados/farmacologia , Tensoativos/química , Varredura Diferencial de Calorimetria , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Ácido Hialurônico/síntese química , Íons , Testes de Sensibilidade Microbiana , Compostos Organofosforados/síntese química , Compostos Organofosforados/química , Espectroscopia de Prótons por Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Temperatura , Termogravimetria , Água/química , Difração de Raios XRESUMO
Ethyl αN-lauroyl l-arginate hydrochloride (LAE) was coupled with hyaluronic acid (HyA) to form ionic complexes with LAE to HyA ratios of 1:1 and 1:2. The complexes were extensively characterized by FTIR and NMR spectroscopies and their thermal properties evaluated by thermogravimetry and calorimetry. Thin films prepared from these complexes by casting displayed a smectic-like structure based on an ordered arrangement of LAE and HyA layers with a nanometric periodicity of 3.8-3.9â¯nm. Films immersed in water at pH 7.4 and 5.5 dissociated to deliver free LAE to the environment and reaching the equilibrium in few hours. The biocide activity of these films against both Gram-positive and Gram-negative bacteria was preliminary assessed by the liquid medium method, and shown to be notable in both cases. The antibacterial property of the complexes was found to increase with the content of LAE and to be particularly efficient against Gram-negative S. enterica bacteria.
Assuntos
Antibacterianos/farmacologia , Arginina/análogos & derivados , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Ácido Hialurônico/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Arginina/química , Arginina/farmacologia , Ácido Hialurônico/química , Íons/química , Íons/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Tamanho da PartículaRESUMO
The change in nitrogen balance causes many environmental and socioeconomic impacts. In relation to food production and nitrogen release in wastewater systems, wastewater and sludge discharge and mineral fertilizer use intensify nitrogen imbalance of a region. The replacement of mineral fertilizer by nitrogen from treated wastewater, biosolids, and treated urine is a promising alternative. This work presents a model to support decision taking for the management of reactive nitrogen flows in wastewater systems based on system dynamics. Six scenarios were simulated for nitrogen flows in wastewater systems and related components.