RESUMO
Pectin is widely used in food and pharmaceutical industries. However, due to its polysaccharide nature it lacks antimicrobial activity. In the current work, new pectin derivatives with interesting optical and antimicrobial properties were prepared via supramolecular chemistry utilizing Fe- or Cu-terpyridine (Tpy-Fe and Tpy-Cu) motifs. To proof derivatization of pectin, ultraviolet-visible spectroscopy (UV-Vis) and Fourier Transform infrared (FTIR) were used. In addition, the prepared pectin derivatives retained the known emulsification activity of the non-modified sugar beet pectin as seen from the particle size analysis of oil-in-water emulsions. The prepared derivatives showed antibacterial activity toward selected Gram-positive and Gram-negative bacteria. In addition, cytotoxicity test showed that the Tpy-Fe-pectin derivative was non-toxic to cells of human hepatocarcinoma, breast adenocarcinoma MCF7, and colorectal carcinoma cells at concentrations up to 100 µg/ml, while Tpy-Cu-pectin had moderate toxicity toward the aforementioned cells at the same concentration levels. The prepared derivatives could have potential applications in emulsions with antibacterial activity.
Assuntos
Antibacterianos/farmacologia , Complexos de Coordenação/farmacologia , Emulsificantes/farmacologia , Pectinas/farmacologia , Piridinas/farmacologia , Antibacterianos/síntese química , Antibacterianos/toxicidade , Beta vulgaris/química , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/toxicidade , Cobre/química , Cobre/toxicidade , Emulsificantes/síntese química , Emulsificantes/toxicidade , Escherichia coli/efeitos dos fármacos , Humanos , Ferro/química , Ferro/toxicidade , Ligantes , Testes de Sensibilidade Microbiana , Pectinas/síntese química , Pectinas/toxicidade , Piridinas/síntese química , Piridinas/toxicidade , Staphylococcus aureus/efeitos dos fármacosRESUMO
Di-2-ethylhexyl phosphate (DEHP) and its main toxic metabolite mono-2-ethylhexyl phthalate (MEHP) are the typical endocrine disrupting chemicals (EDCs) and widely affect human health. Our previous research reported that synthetic nonionic dietary emulsifier polysorbate 80 (P80, E433) had the promotional effect on the oral absorption of DEHP in rats. The aim of this study was to explore its mechanism of promoting oral absorption, focusing on the mucus barrier and mucosal barrier of the small intestine. A small molecule fluorescent probe 5-aminofluorescein-MEHP (MEHP-AF) was used as a tracker of MEHP in vivo and in vitro. First of all, we verified that P80 promoted the bioavailability of MEHP-AF in the long-term and low-dose exposure of MEHP-AF with P80 as a result of increasing the intestinal absorption of MEHP-AF. Afterwards, experimental results from Western blot, qPCR, immunohistochemistry, and immunofluorescence showed that P80 decreased the expression of proteins (mucus protein mucin-2, tight junction proteins claudin-1 and occludin) related to mucus barrier and mucosal barrier in the intestine, changed the integrity of intestinal epithelial cell, and increased the permeability of intestinal epithelial mucosa. These results indicated that P80 promoted the oral absorption of MEHP-AF by altering the intestinal mucus barrier and mucosal barrier. These findings are of great importance for assessing the safety risks of some food emulsifiers and clarifying the absorption mechanism of chemical pollutants in food, especially for EDCs.
Assuntos
Dietilexilftalato/análogos & derivados , Emulsificantes/toxicidade , Células Epiteliais/efeitos dos fármacos , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Polissorbatos/toxicidade , Animais , Disponibilidade Biológica , Células CACO-2 , Claudina-1/metabolismo , Dietilexilftalato/farmacocinética , Dietilexilftalato/toxicidade , Células Epiteliais/metabolismo , Fluoresceínas/metabolismo , Corantes Fluorescentes/metabolismo , Células HT29 , Humanos , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Masculino , Camundongos Endogâmicos ICR , Mucina-2/metabolismo , Ocludina/metabolismo , Permeabilidade , Ratos Sprague-Dawley , Distribuição Tecidual , ToxicocinéticaRESUMO
Human beings are increasingly exposed to phthalates, which are a group of chemicals used to make plastics more flexible and harder to break, and simultaneously ingesting abundant food emulsifiers via daily diet. The purpose of this study was to investigate the effect of the food emulsifier glycerin monostearate (GMS) on male reproductive toxicity caused by di(2-ethylhexyl) phthalate (DEHP, one of the phthalates) and explore the underlying mechanism. Thirty male Sprague-Dawley rats were randomly divided into control group, DEHP group and DEHP+GMS group. Rats in the DEHP group and DEHP+GMS group were orally administered with 200 mg/kg/d DEHP with or without 20 mg/kg/d GMS. After 30 days of continuous intervention, it was found that the serum testosterone level was significantly lowered in DEHP group and DEHP+GMS group than that in control group (P<0.01). The serum testosterone level and the relative testis weight were significantly decreased in the DEHP+GMS group as compared with those in the DEHP group and control group (P<0.05). More spermatids were observed to be shed off in DEHP+GMS group than in DEHP group. The expression levels of cell cycle checkpoint kinase 1 (Chk1), cell division cycle gene 2 (Cdc2), and cyclin-dependent kinase 2 (CDK2) were down-regulated in DEHP group, and this tendency was more significant in DEHP+GMS group (P<0.05 or P<0.01). There was no significant difference in the P-glycoprotein (P-gp) expression between DEHP group and control group. However, P-gp was markedly down-regulated in DEHP+GMS group (P<0.01). The results indicated that the food emulsifier GMS aggravated the toxicity of DEHP on male reproduction by inhibiting the cell cycle of testicular cells and the expression of P-gp in testis tissues.
Assuntos
Dietilexilftalato/toxicidade , Emulsificantes/toxicidade , Glicerol/toxicidade , Reprodução/efeitos dos fármacos , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Administração Oral , Animais , Proteína Quinase CDC2/metabolismo , Quinase 1 do Ponto de Checagem/metabolismo , Quinase 2 Dependente de Ciclina/metabolismo , Dietilexilftalato/administração & dosagem , Regulação para Baixo , Emulsificantes/administração & dosagem , Glicerol/administração & dosagem , Masculino , Tamanho do Órgão/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Testículo/efeitos dos fármacos , Testosterona/sangueRESUMO
In the present work, the production of bioemulsifier (BE) by a lactic acid bacterium (LAB) grown at 25⯰C in lactic whey-based media for 24â¯h was evaluated. Maximum production was detected in a medium containing yeast extract, peptone and lactic whey (LAPLW medium), with a yield of 270â¯mgâ¯L-1. The BE proved to be more innocuous for Caco-2â¯cells, used as a toxicological indicator, than the non-ionic surfactant Triton X-100. In addition, the microbial product presented higher stability to changes in temperature (37⯰C to 100⯰C), pH (2-10), and salt concentration (5% and 20%, w/v) than the synthetic surfactant. Regarding emulsifying capacity tested against different hydrophobic substrates (kerosene, motor oil, diesel, sunflower oil, and grape oil), the BE displayed E24 values similar to or even better than those of Triton X-100. Finally, Triton X-100 caused irreversible modifications on the giant unilamellar vesicles (used as model membrane system), promoting the solubilization of the lipid bilayers. Nevertheless, BE induced temporary modifications of the membrane, which is associated with incorporation of the bioproduct in the outer layer. These results demonstrate the role of BE in biological processes, including reversible changes in microbial membranes to enhance the access to hydrophobic substrates.
Assuntos
Biotecnologia/métodos , Emulsificantes/isolamento & purificação , Enterococcus/metabolismo , Ácido Láctico/metabolismo , Soro do Leite/metabolismo , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Emulsificantes/metabolismo , Emulsificantes/toxicidade , Emulsões , Humanos , Interações Hidrofóbicas e Hidrofílicas , Octoxinol/química , Petróleo/metabolismo , Óleos de Plantas/metabolismo , TemperaturaRESUMO
The objectives of the study are to develop and characterise formulations with volatile molecules in an emulsifiable concentrate form, for their antimicrobial properties and to evaluate their efficacies against Colletotrichum gloeosporioides Penz., to control anthracnose in mangoes after harvest. Results showed EC39 and EC40 among formulations were characterised for their excellent emulsification properties, the droplet size of 192.34 ± 0.48 nm and 227.4 ± 0.71 nm and Zeta potential of -52.5 ± 2.76 mv and -48.84 ± 2.62 mv, respectively, with better storage stability at 10 ± 20 °C and RH 80 ± 5%. In vitro assay, 100% inhibition of visual spore germination by 0.15% and 0.2% MIC value for EC39 and EC40, respectively Studies on the efficacy of their fungicide properties also indicated the IC50 value of 0.161% and 0.162% for EC39 and EC40 respectively for mycelial growth inhibition. In vivo testing too, EC39 and EC40 effectively controlled anthracnose incidence in mango in a dosage-dependent manner.
Assuntos
Colletotrichum/efeitos dos fármacos , Emulsificantes/toxicidade , Fungicidas Industriais/toxicidade , Mangifera/microbiologia , Doenças das Plantas/prevenção & controle , Compostos Orgânicos Voláteis/toxicidade , Acetaldeído/análogos & derivados , Acetaldeído/química , Acetaldeído/toxicidade , Acroleína/análogos & derivados , Acroleína/química , Acroleína/toxicidade , Monoterpenos Acíclicos , Colletotrichum/crescimento & desenvolvimento , Emulsificantes/química , Emulsões/química , Emulsões/toxicidade , Fungicidas Industriais/química , Monoterpenos/química , Monoterpenos/toxicidade , Doenças das Plantas/microbiologia , Compostos Orgânicos Voláteis/químicaRESUMO
Dietary emulsifiers carboxylmethylcellulose (CMC) and polysorbate 80 (P80) alter the composition of the intestinal microbiota and induce chronic low-grade inflammation, ultimately leading to metabolic dysregulations in mice. As both gut microbiota and intestinal health can influence social and anxiety-like behaviors, we investigated whether emulsifier consumption would detrimentally influence behavior. We confirmed that emulsifier exposure induced chronic intestinal inflammation, increased adiposity, and altered gut microbiota composition in both male and female mice, although the specific microboal taxa altered following emulsifier consumption occurred in a sex-dependent manner. Importantly, emulsifier treatment altered anxiety-like behaviors in males and reduced social behavior in females. It also changed expression of neuropeptides implicated in the modulation of feeding as well as social and anxiety-related behaviors. Multivariate analyses revealed that CMC and P80 produced distinct clustering of physiological, neural, and behavioral effects in male and female mice, suggesting that emulsifier treatment leads to a syndrome of sex-dependent changes in microbiota, physiology, and behavior. This study reveals that these commonly used food additives may potentially negatively impact anxiety-related and social behaviors and may do so via different mechanisms in males and females.
Assuntos
Ansiedade/induzido quimicamente , Carboximetilcelulose Sódica/toxicidade , Emulsificantes/toxicidade , Inflamação/induzido quimicamente , Polissorbatos/toxicidade , Adiposidade , Animais , Comportamento Animal , Feminino , Microbioma Gastrointestinal , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Comportamento SocialRESUMO
We prepared mineral oil-based emulsion adjuvants by employing simple self-emulsifying drug delivery system (SEDDS). Mineral oil emulsions (3%, 5%, and 7%) were prepared using deionized water and C-971P NF and C-940 grade carbomer solutions with concentrations 0.01% (w/v) and 0.02% (w/v). In total, 15 emulsions were prepared and mixed with a solution containing inactivated Mycoplasma hyopneumoniae (J101 strain) antigen and porcine circovirus type 2 antigen to prepare vaccines. Droplet sizes in the submicron range and zeta potential values between - 40 and 0 mV were maintained by most emulsion adjuvants for a period of 6 months. Emulsion adjuvants were regarded safe, and their M. hyopneumoniae-specific IgG, IgG1, and IgG2a titers were either better or comparable to those of aluminum gel.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Emulsificantes/toxicidade , Imunoglobulina G/imunologia , Óleo Mineral/toxicidade , Mycoplasma hyopneumoniae/imunologia , Água , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/toxicidade , Animais , Emulsificantes/administração & dosagem , Emulsões/administração & dosagem , Emulsões/toxicidade , Camundongos , Camundongos Endogâmicos BALB C , Óleo Mineral/administração & dosagem , Mycoplasma hyopneumoniae/efeitos dos fármacos , Suínos , Água/administração & dosagemRESUMO
Human beings are inevitably exposed to ubiquitous phthalate esters (PEs), and simultaneously ingesting high quantities of food emulsifiers via daily diet. Glycerin monostearate (GMS) is a widely used food emulsifier. The purposes of this study were to investigate the combined effects between the mixture of six frequently used PEs (MIXPs) and GMS on male rat reproductive system, and further to explore the underlying mechanisms. Male rats were orally administered either sodium carboxymethyl cellulose as controls or MIXPs at three different low-doses with or without GMS (200mg/kg/d) by gavage. The 15-week exposure of MIXPs caused male reproductive toxicity in a dose- and time-dependent manner, including the decrease of serum testosterone and morphological damage of testis. Metabonomics analyses of urine and Western blotting analyses of steroidogenic proteins (StAR, P450scc, CYP17A1, 17ß-HSD and P450arom) indicated that MIXPs exposure down-regulated the expression of steroidogenic proteins, and might alter androgen metabolism. The results also showed that the presence of GMS exacerbated the toxicities of MIXPs to male rat reproductive system. These findings suggest that food emulsifier GMS could enhance the toxic effects of MIXPs on male hormone biosynthesis.
Assuntos
Emulsificantes/toxicidade , Genitália Masculina/efeitos dos fármacos , Genitália Masculina/metabolismo , Glicerol/toxicidade , Ácidos Ftálicos/toxicidade , Testosterona/sangue , Animais , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Emulsificantes/administração & dosagem , Glicerol/administração & dosagem , Masculino , Ácidos Ftálicos/administração & dosagem , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Testículo/efeitos dos fármacos , Testículo/metabolismoRESUMO
A new amphiphilic antioxidant (tannyl stearate) derived from reaction of tannic acid with stearic acid was synthesized in order to improve tannic acid solubility in lipid materials. This reaction gives many products having different degree of esterification (tannyl mono, di, tri, tetra, penta, hexa, hepta stearate) which were separated using silica gel column chromatography and tentative identification was carried out using thin layer chromatography (TLC). The intrinsic viscosities (η) were used to differentiate between the different molecular weight of the produced esters1). Tannyl penta stearate is assumed to be the most suitable amphiphilic antioxidant derivative, where those derivatives with less degree of esterification would be less soluble in fat, and those of higher degree of esterification would exhaust more hydroxyl group that cause decreases of antioxidant activity. The structure of tannyl penta stearate was approved depending on its chemical analysis and spectral data (IR, H1 NMR,). The emulsification power of tannyl penta stearate was then determined according to method described by El-Sukkary et al.2), in order to prove its amphiphilic property. Then tannyl penta stearate was tested for its antioxidant and radical scavenging activities in three different manners, those are, lipid oxidation in sunflower oil using Rancimat, (DPPH) free radical scavenging and total antioxidant activity. {Pure tannic acid (T), butylhydroxyanisol (BHA) and butylhydroxytoluene (BHT) were used as reference antioxidant radical saving compounds}. Then tannyl penta stearate was added to sunflower oil, frying process was carried out and all physicochemical parameters of the oil were considered, and compared to other reference antioxidant in order to study the effect of this new antioxidant toward oil stability. Acute oral toxicity of the tannyl penta stearate was carried out using albino mice of 21-25 g body weight to determine its safety according to the method described by Goodman et al.3). Also liver and kidney functions of those mice were checked. Thus it could be concluded that the addition of tannyl penta stearate to frying oils offers a good protection against oxidation. The effectiveness of tannyl penta stearate as lipid antioxidant has been attributed mainly to its stability at high temperature. And according to acute lethal toxicity test tannyl penta stearate was found to be a safe compound that can be used as food additive.
Assuntos
Antioxidantes/síntese química , Emulsificantes/síntese química , Estearatos/síntese química , Taninos/síntese química , Animais , Antioxidantes/farmacologia , Antioxidantes/toxicidade , Compostos de Bifenilo/química , Hidroxianisol Butilado/química , Hidroxitolueno Butilado/química , Emulsificantes/farmacologia , Emulsificantes/toxicidade , Ácidos Graxos/química , Sequestradores de Radicais Livres/síntese química , Sequestradores de Radicais Livres/farmacologia , Sequestradores de Radicais Livres/toxicidade , Testes de Função Renal , Testes de Função Hepática , Camundongos , Picratos/química , Ratos , Solubilidade , Estearatos/farmacologia , Estearatos/toxicidade , Ácidos Esteáricos/química , Óleo de Girassol/química , Taninos/química , Taninos/farmacologia , Taninos/toxicidade , ViscosidadeRESUMO
The increased risks conferred by inflammatory bowel disease (IBD) to the development of colorectal cancer gave rise to the term "colitis-associated cancer" and the concept that inflammation promotes colon tumorigenesis. A condition more common than IBD is low-grade inflammation, which correlates with altered gut microbiota composition and metabolic syndrome, both present in many cases of colorectal cancer. Recent findings suggest that low-grade inflammation in the intestine is promoted by consumption of dietary emulsifiers, a ubiquitous component of processed foods, which alter the composition of gut microbiota. Here, we demonstrate in a preclinical model of colitis-induced colorectal cancer that regular consumption of dietary emulsifiers, carboxymethylcellulose or polysorbate-80, exacerbated tumor development. Enhanced tumor development was associated with an altered microbiota metagenome characterized by elevated levels of lipopolysaccharide and flagellin. We found that emulsifier-induced alterations in the microbiome were necessary and sufficient to drive alterations in major proliferation and apoptosis signaling pathways thought to govern tumor development. Overall, our findings support the concept that perturbations in host-microbiota interactions that cause low-grade gut inflammation can promote colon carcinogenesis. Cancer Res; 77(1); 27-40. ©2016 AACR.
Assuntos
Transformação Celular Neoplásica/induzido quimicamente , Colite/induzido quimicamente , Neoplasias do Colo/induzido quimicamente , Emulsificantes/toxicidade , Aditivos Alimentares/toxicidade , Animais , Carboximetilcelulose Sódica/toxicidade , Colite/microbiologia , Neoplasias do Colo/microbiologia , Modelos Animais de Doenças , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Polissorbatos/toxicidadeRESUMO
The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to function in cosmetics as surfactants, skin-conditioning agents, and/or emulsifying agents. The alkyl PEG/PPG ethers share very similar physiochemical properties as the alkyl PEG ethers, which were reviewed previously by the CIR Expert Panel and found safe when formulated to be nonirritating. The alkyl PEG ethers differ by the inclusion of PPG repeat units, which are used to fine-tune the surfactant properties of this group. The Panel relied heavily on data on analogous ingredients, extracted from the alkyl PEG ethers and PPG reports, when making its determination of safety.
Assuntos
Qualidade de Produtos para o Consumidor , Cosméticos , Éteres/toxicidade , Polietilenoglicóis/toxicidade , Propilenoglicóis/toxicidade , Alquilação , Animais , Fármacos Dermatológicos/química , Fármacos Dermatológicos/farmacocinética , Fármacos Dermatológicos/toxicidade , Emulsificantes/química , Emulsificantes/farmacocinética , Emulsificantes/toxicidade , Éteres/química , Éteres/farmacocinética , Humanos , Polietilenoglicóis/química , Polietilenoglicóis/farmacocinética , Propilenoglicóis/química , Propilenoglicóis/farmacocinética , Tensoativos/química , Tensoativos/farmacocinética , Tensoativos/toxicidade , Testes de ToxicidadeRESUMO
The aim of the present research was to explore whether food emulsifier polysorbate 80 can enhance the absorption of di-(2-ethylhexyl) phthalate (DEHP) and its possible mechanism. We established the high-performance liquid chromatography (HPLC) method for detecting DEHP and its major metabolite, mono-ethylhexyl phthalate (MEHP) in rat plasma, and then examined the toxicokinetic and bioavailability of DEHP with or without polysorbate 80 in rats. The study of its mechanism to increase the absorption of phthalates demonstrated that polysorbate 80 can induce mitochondrial dysfunction in time- and concentration-dependence manners in Caco-2 cells by reducing mitochondrial membrane potential, diminishing the production of the adenosine triphosphate, and decreasing the activity of electron transport chain. Our results indicated that food emulsifier applied in relatively high concentrations in even the most frequently consumed foods can increase the absorption of DEHP, and its role may be related to the structure and function damages of mitochondria in enterocytes.
Assuntos
Dietilexilftalato/farmacocinética , Emulsificantes/toxicidade , Aditivos Alimentares/toxicidade , Absorção Intestinal/efeitos dos fármacos , Polissorbatos/toxicidade , Animais , Disponibilidade Biológica , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Dietilexilftalato/sangue , Dietilexilftalato/metabolismo , Dietilexilftalato/toxicidade , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Ratos Sprague-Dawley , ToxicocinéticaRESUMO
PURPOSE: The present work focuses on the in vivo evaluation of tamoxifen and quercetin combination loaded into solid self-nanoemulsifying drug delivery system (s-Tmx-QT-SNEDDS). METHODS: Lyophilization was employed to prepare s-Tmx-QT-SNEDDS using Aerosil 200 as carrier. The developed formulation was evaluated for in vitro cell cytotoxicity, in vivo pharmacokinetics, antitumor efficacy and toxicity studies. RESULTS: In vivo pharmacokinetics revealed ~8-fold and ~4-fold increase in oral bioavailability of tamoxifen and quercetin, respectively as compared to free counterparts. s-Tmx-QT-SNEDDS exhibited significantly higher cell cytotoxicity, as compared to free drug combination revealing ~32-fold and ~22-fold higher dose reduction index for tamoxifen and quercetin, respectively estimated using median effect dose analysis. s-Tmx-QT-SNEDDS could suppress tumor growth in DMBA induced tumor bearing animals by ~80% in contrast to ~35% observed with tamoxifen citrate. The significant appreciation in antitumor efficacy was further supported by normalized levels of tumor angiogenesis markers (MMP-2 and MMP-9). Finally, complete obliteration in tamoxifen induced hepatotoxicity was observed upon administration of developed formulation in contrast to that of clinically available tamoxifen citrate when measured as function of hepatotoxicity markers and histopathological changes. CONCLUSIONS: In nutshell, co-encapsulation of quercetin with tamoxifen in solid SNEDDS poses great potential in improving the therapeutic efficacy and safety of tamoxifen.
Assuntos
Antineoplásicos/farmacocinética , Técnicas de Química Combinatória/métodos , Sistemas de Liberação de Medicamentos/métodos , Emulsificantes/farmacocinética , Fígado/metabolismo , Nanopartículas/metabolismo , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/toxicidade , Química Farmacêutica , Emulsificantes/administração & dosagem , Emulsificantes/toxicidade , Feminino , Humanos , Fígado/efeitos dos fármacos , Fígado/patologia , Células MCF-7 , Nanopartículas/administração & dosagem , Nanopartículas/toxicidade , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Tamoxifeno/administração & dosagem , Tamoxifeno/farmacocinética , Tamoxifeno/toxicidadeRESUMO
A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecular weight (700 kDa), non-ionic molecule. Gas chromatography of the lipid fraction revealed the presence of palmitic, stearic, and oleic acids; thus microbactan may be considered a glycolipoprotein. Microbactan emulsified aromatic hydrocarbons and oils to various extents; the highest emulsification index was recorded against motor oil (96%). The stability of the microbactan-motor oil emulsion model reached its highest level (94%) at 50 °C, pH 10 and 3.5% NaCl content. It was not toxic to Artemia salina nauplii. Microbactan is, therefore, a non-toxic and non-ionic bioemulsifier of high molecular weight with affinity for a range of oily substrates. Comparative phylogenetic assessment of the 16S rDNA gene of Microbacterium sp. MC3B-10 with genes derived from other marine Microbacterium species suggested that this genus is well represented in coastal zones. The chemical nature and stability of the bioemulsifier suggest its potential application in bioremediation of marine environments and in cosmetics.
Assuntos
Actinomycetales/metabolismo , Emulsificantes/metabolismo , Actinomycetales/classificação , Animais , Artemia/efeitos dos fármacos , Biodegradação Ambiental , Emulsificantes/química , Emulsificantes/toxicidade , Hidrocarbonetos Aromáticos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Óleos/química , Ácido Oleico/química , Ácido Palmítico/química , Filogenia , Ácidos Esteáricos/química , TemperaturaRESUMO
Microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS2003) on microbial community dynamics. An experimental seawater microcosm, supplemented with crude oil and EPS2003 (SW+OIL+EPS2003), was monitored for 15 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out during all experimentation period. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil degradation was monitored by GC-MS analysis. Bioemulsificant addition stimulated an increase of the total bacterial abundance, change in the community structure and activity. The bioemulsificant also increased of 5 times the oil biodegradation rate. The data obtained from microcosm experiment indicated that EPS2003 could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.
Assuntos
Bactérias/efeitos dos fármacos , Ecossistema , Emulsificantes/toxicidade , Poluição por Petróleo , Polissacarídeos/toxicidade , Poluentes Químicos da Água/toxicidade , Bactérias/classificação , Bactérias/metabolismo , Biodegradação Ambiental , Contagem de Colônia Microbiana , Processos Heterotróficos , Hidrocarbonetos/análise , Hidrocarbonetos/metabolismo , Petróleo/análise , Petróleo/metabolismo , Água do Mar/química , Água do Mar/microbiologia , Microbiologia da ÁguaRESUMO
The aims of this work were the characterisation and the evaluation of potential environmental applications of the bioemulsifiers produced by Variovorax paradoxus 7bCT5. V. paradoxus 7bCT5 produces a mixture of high molecular weight polysaccharides. The extracellular bioemulsifiers were able to produce a thick stable oil/water emulsion and maintained the emulsification activity after boiling and at low temperatures. Environmental behavior and impact of bioemulsifiers release were assessed by evaluating biodegradability, toxicity and soil sorption. Respirometric tests showed that moderate biodegradability occurred by soil bacterial inoculum. Furthermore, the produced compounds did not show any toxic properties through different ecotoxicological tests. The K(d) values ranged from 1.3 to 7.3 L/kg indicating a high sorption affinity of the bioemulsifier molecules to soil particles. The soil sorption affinity likely affected the bioemulsifier ability to remove hydrocarbons from contaminated soils. In fact, V. paradoxus 7bCT5 bioemulsifiers significantly increased the removal of crude-oil from sandy soil compared to water.
Assuntos
Comamonadaceae/química , Emulsificantes/metabolismo , Emulsificantes/toxicidade , Microbiologia Industrial/métodos , Poluentes do Solo/metabolismo , Adsorção , Biodegradação Ambiental , Petróleo/metabolismo , Testes de ToxicidadeRESUMO
COREXIT EC9500A (COREXIT) was used to disperse crude oil during the 2010 Deepwater Horizon oil spill. While the environmental impact of COREXIT has been examined, the pulmonary effects are unknown. Investigations were undertaken to determine whether inhaled COREXIT elicits airway inflammation, alters pulmonary function or airway reactivity, or exerts pharmacological effects. Male rats were exposed to COREXIT (mean 27 mg/m(3), 5 h). Bronchoalveolar lavage was performed on d 1 and 7 postexposure. Lactate dehydrogenase (LDH) and albumin were measured as indices of lung injury; macrophages, neutrophils, lymphocytes, and eosinophils were quantified to evaluate inflammation; and oxidant production by macrophages and neutrophils was measured. There were no significant effects of COREXIT on LDH, albumin, inflammatory cell levels or oxidant production at either time point. In conscious animals, neither breathing frequency nor specific airway resistance were altered at 1 hr, 1 d and 7 d postexposure. Airway resistance responses to methacholine (MCh) aerosol in anesthetized animals were unaffected at 1 and 7 d postexposure, while dynamic compliance responses were decreased after 1 d but not 7 d. In tracheal strips, in the presence or absence of MCh, low concentrations of COREXIT (0.001% v/v) elicited relaxation; contraction occurred at 0.003-0.1% v/v. In isolated, perfused trachea, intraluminally applied COREXIT produced similar effects but at higher concentrations. COREXIT inhibited neurogenic contractile responses of strips to electrical field stimulation. Our findings suggest that COREXIT inhalation did not initiate lung inflammation, but may transiently increase the difficulty of breathing.
Assuntos
Emulsificantes/toxicidade , Recuperação e Remediação Ambiental/efeitos adversos , Exposição por Inalação/efeitos adversos , Lipídeos/toxicidade , Pneumonia/induzido quimicamente , Resistência das Vias Respiratórias/efeitos dos fármacos , Albuminas/metabolismo , Animais , Lavagem Broncoalveolar , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Citocinas/metabolismo , Lactato Desidrogenases/metabolismo , Medições Luminescentes , Masculino , Poluição por Petróleo , Pneumonia/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Testes de Função Respiratória , Testes de Toxicidade Aguda , Traqueia/efeitos dos fármacosRESUMO
An automated whole-body inhalation exposure system capable of exposing 12 individually housed rats was designed to examine the potential adverse health effects of the oil dispersant COREXIT EC9500A, used extensively during the Deepwater Horizon oil spill. A computer-controlled syringe pump injected the COREXIT EC9500A into an atomizer where droplets and vapor were formed and mixed with diluent air. The aerosolized COREXIT EC9500A was passed into a customized exposure chamber where a calibrated light-scattering instrument estimated the real-time particle mass concentration of the aerosol in the chamber. Software feedback loops controlled the chamber aerosol concentration and pressure throughout each exposure. The particle size distribution of the dispersant aerosol was measured and shown to have a count median aerodynamic diameter of 285 nm with a geometric standard deviation of 1.7. The total chamber concentration (particulate + vapor) was determined using a modification of the acidified methylene blue spectrophotometric assay for anionic surfactants. Tests were conducted to show the effectiveness of closed loop control of chamber concentration and to verify chamber concentration homogeneity. Five automated 5-h animal exposures were performed that produced controlled and consistent COREXIT EC9500A concentrations (27.1 ± 2.9 mg/m(3), mean ± SD).
Assuntos
Emulsificantes/toxicidade , Recuperação e Remediação Ambiental/efeitos adversos , Exposição por Inalação/efeitos adversos , Lipídeos/toxicidade , Modelos Animais , Poluição por Petróleo , Testes de Toxicidade/métodos , Aerossóis , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Software , Testes de Toxicidade/instrumentaçãoRESUMO
These studies characterized cardiovascular responses after an acute inhalation exposure to COREXIT EC9500A, the oil dispersant used in the Deepwater Horizon oil spill. Male Sprague-Dawley rats underwent a single 5-h inhalation exposure to COREXIT EC9500A (average exposure level 27.12 mg/m(3)) or air. On d 1 and 7 following the exposure, rats were implanted with indwelling catheters and changes in heart rate and blood pressure were assessed in response to increasing levels of adrenoreceptor agonists. A separate group of rats was euthanized at the same time points, ventral tail arteries were dissected, and vascular tone along with dose-dependent responses to vasoconstricting and dilating factors were assessed in vitro. Agonist-induced dose-dependent increases in heart rate and blood pressure were greater in COREXIT EC9500A-exposed than in air-exposed rats at 1 d but not 7 d after the exposure. COREXIT EC9500A exposure also induced a rise in basal tone and reduced responsiveness of tail arteries to acetylcholine-induced vasodilation at 1 d but not 7 d following the exposure. These findings demonstrate that an acute exposure to COREXIT EC9500A exerts transient effects on cardiovascular and peripheral vascular functions.