Sensitized photo-oxidation of gadusol species mediated by singlet oxygen

Gadusols are efficient nature UV sunscreens with antioxidant capacity. The kinetics of the quenching reactionsof singlet oxygen O2(1Δg) by gadusol species was evaluated in aqueous solution as well as in the presenceof direct charged micelles. Time-resolved phosphorescence detection of O2(1Δg) indicated that gadusolate, themain species under biological pH, is a more efficient quencher than the enol form with a rate constant of ca.1.3 × 108 L mol−1 s−1. The deactivation proceeds via a collisional mechanism with clear dominance of chemicalpathways, according to the rates of gadusol and oxygen consumptions, and typical photooxidation quantumyields of ca. 7%. The relative contributions of the chemical and physical quenching steps were not affected bythe presence of anionic or cationic micelles emulating simple pseudo-biological environments. The products ofthe photo-oxidative quenching support a type II mechanism initiated by the addition of O2(1Δg) to the C-C doublebond of gadusolate. These results point to the relevance of considering the role of sacrifice antioxidant along withthe UV-screening function for gadusol, particularly in the context of potential biotechnological applications ofthis natural molecule.Fil: Orallo, Dalila Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Físicas de Mar del Plata; Argentina. Departamento de Química y Bioquímica; ArgentinaFil: Lores, Nayla Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Arbeloa, Ernesto Maximiliano. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Bertolotti, Sonia Graciela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Churio, María Sandra. Departamento de Química y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Físicas de Mar del Plata; Argentin

Honeybees (Apis mellifera) as biomonitors of environmental pollution by heavy metals

En este trabajo se estudió el uso de colonias de abejas (Apis mellifera) como biomonitores de contaminación ambiental por metales pesados. Para ello se evaluó la concentración de Cd (cadmio), Cr (cromo), Ni (níquel), Pb (plomo) y Zn (cinc) en abejas, polen y miel colectadas en apiarios ubicados en tres zonas con diferentes fuentes de contaminación. Los muestreos para la determinación de metales pesados se realizaron en cada apiario una vez al mes, durante doce meses. Las muestras de abejas y polen fueron procesadas mediante digestión ácida y las soluciones resultantes fueron analizadas mediante espectrofotometría de absorción atómica. En tanto que las muestras de miel se procesaron por digestión en microondas y la detección fue realizada en espectrómetro de fluorescencia de rayos X por reflexión total. Las concentraciones de cada uno de los metales fueron determinadas en relación al peso seco de las muestras. Los datos obtenidos indicaron que los cinco metales pudieron ser detectados en abeja y polen y solo pudo ser determinado el cinc en las muestras de miel. La matriz que mejor resulto como biomonitor de contaminación por metales pesados resulto ser la abeja.In this work, bee’s colonies (Apis mellifera) as biomonitors of environmental contamination by heavy metals was studied. The concentration of Cd (cadmium), Cr (chromium), Ni (nickel), Pb (lead) and Zn (zinc) in bees, pollen and honey collected in apiarie located in three areas with different sources of contamination was evaluated. Sampling for determination of heavy metals was conducted in each apiary once a month, for twelve months. Bee and pollen samples were processed by acid digestion, and the resulting solutions were analyzed by atomic absorption spectrophotometry. Honey samples were processed by microwave digestion, and detection was performed using total reflection X-ray fluorescence spectrometry. The concentrations of each of the metals were determined in relation to the dry weight of the samples. Findings showed that the five metals could be detected in bee and pollen, while only zinc could be determined in honey samples. The bee matrix proved to be the most effective biomonitor for heavy metal contamination.Fil: Cecchi, Manuel. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Basso, Marilina. Comisión Nacional de Energía Atómica; ArgentinaFil: Cantatore, Delfina María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Moliné, Maria de la Paz. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Fernández, Natalia Jorgelina. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Dominguez, Enzo. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Churio, Maria Sandra. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Físicas de Mar del Plata; ArgentinaFil: Gende, Liesel Brenda. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentin

Antioxidant activity of gadusol and occurrence in fish roes from Argentine Sea

The occurrence of the natural antioxidant gadusol (3,5,6-trihydroxy-5-hydroxymethyl-2-methoxycyclohex-2-en-1-one) was quantified in fish roes of three species from Argentine Sea: argentine hake (Merluccius hubbsi), brazilian sandperch (Pinguipes brasilianus) and argentinian sandperch (Pseudopercis semifasciata). Significant yields of the compound were found in the sandperchs. The antioxidant activity of the isolated metabolite in aqueous solution was assessed by ORAC and ABTS assays and compared with that of other known natural antioxidants. The results indicate that gadusol is a good breaker of chain reactions carried by peroxyl radicals. Besides, its ability to reduce radicals is comparable to that of ascorbic acid. On this basis, fish roes from brazilian and argentinian sandpearchs are proposed as useful sources of antioxidants for human consumption. © 2009 Elsevier Ltd. All rights reserved.Fil: Arbeloa, Ernesto Maximiliano. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Uez, María J.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaFil: Bertolotti, Sonia Graciela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Churio, Maria Sandra. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Anthelminthic activity of glibenclamide on secondary cystic echinococcosis in mice

<div><p>Cystic echinococcosis (CE) is a worldwide parasitic zoonosis caused by the larval stage of <i>Echinococcus granulosus</i>. Current chemotherapy against this disease is based on the administration of benzimidazoles (BZMs). However, BZM treatment has a low cure rate and causes several side effects. Therefore, new treatment options are needed. The antidiabetic drug glibenclamide (Glb) is a second-generation sulfonylurea receptor inhibitor that has been shown to be active against protozoan parasites. Hence, we assessed the <i>in vitro</i> and <i>in vivo</i> pharmacological effects of Glb against the larval stage of <i>E</i>. <i>granulosus</i>. The <i>in vitro</i> activity was concentration dependent on both protoscoleces and metacestodes. Moreover, Glb combined with the minimum effective concentration of albendazole sulfoxide (ABZSO) was demonstrated to have a greater effect on metacestodes in comparison with each drug alone. Likewise, there was a reduction in the cyst weight after oral administration of Glb to infected mice (5 mg/kg of body weight administered daily for a period of 8 weeks). However, in contrast to <i>in vitro</i> assays, no differences in effectiveness were found between Glb + albendazole (ABZ) combined treatment and Glb monotherapy. Our results also revealed mitochondrial membrane depolarization and an increase in intracellular Ca²⁺ levels in Glb-treated protoscoleces. In addition, the intracystic drug accumulation and our bioinformatic analysis using the available <i>E</i>. <i>granulosus</i> genome suggest the presence of genes encoding sulfonylurea transporters in the parasite. Our data clearly demonstrated an anti-echinococcal effect of Glb on <i>E</i>. <i>granulosus</i> larval stage. Further studies are needed in order to thoroughly investigate the mechanism involved in the therapeutic response of the parasite to this sulfonylurea.</p></div

<i>In vitro</i> effect of glibenclamide on viability of <i>E</i>. <i>granulosus</i> protoscoleces.

<p>(A) Viability of protoscoleces incubated for 20 days with 0.2, 2 and 10 mM of glibenclamide (Glb). Parasites incubated in culture medium containing DMSO served as controls. The protoscolex viability was determined every two days by the methylene blue exclusion test (at least 100 protoscoleces per replica were counted each time). Data are the mean ± S.D. of three independent experiments. *Statistically significant difference (<i>p</i> < 0.05) compared with control. (B) Representative SEM images of control protoscoleces (a) or treated with 10 mM Glb for 7 days (b, c). (a) Invaginated control protoscolex; (b, c) Evaginated treated protoscoleces, with altered tegument in the soma region and loss of microtrichias on the escolex region. Bars indicate: 20 μm.</p

Effect of glibenclamide on intracellular calcium levels in <i>E</i>. <i>granulosus</i> protoscoleces.

<p>(A) Protoscoleces were incubated with buffer (Co), 200 μM glibenclamide (Glb) or 10μM trifluoperazine (TFP, positive control) for 2 h and then loaded with Fluo3-AM ester solution in darkness. Data are the mean ± S.D. of three independent experiments. *Statistically significant difference (<i>p</i> < 0.05) compared with control. (B) Free calcium profiles in protoscoleces. Prototype kinetics shown the fluorescence increase with Fluo3-AM. Fo, initial fluorescence; Fm, maximum fluorescence; Fx, final fluorescence. The graphic shows the free calcium decay to baseline within about 600 s with a partial recovery of the initial fluorescence which reveals a strong gradient in the calcium signal during the treatment of this puricellular organism with Glb. (C) Confocal imaging reveled intracellular calcium increase in Glb-treated protoscoleces. Photomicroscopy of light field (a, c) and of fluorescence field (b, d). Control (a, b); protoscoleces treated with Glb (c, d). Bars indicate: 100 μm.</p

Mitochondrial membrane potential in glibenclamide treated-protoscoleces.

<p>(A) Representative confocal images showing JC-1 fluorescence in protoscoleces incubated under control conditions (a-d) or treated with 200 μM glibenclamide (Glb, e-h) for 24 h. tg: tegument; rc: rostellar cone; su: sucker. Bars indicate 50 μm. Red and yellow dots indicated by arrowheads correspond to stained calcareous corpuscles. (B) Boxplot graph showing the values of the red/green JC-1 fluorescence ratios measured in control (Co) and Glb-treated protoscoleces by Image J Software. *Statistically significant difference (<i>p</i> < 0.05) compared with control.</p

<i>In vitro</i> effect of glibenclamide and its combination with albendazole sulfoxide on viability of <i>E</i>. <i>granulosus</i> metacestodes.

<p>(A) Viability of metacestodes (MTC) incubated for 5 days with 10, 50, 100 and 200 μM of glibenclamide alone (Glb), 2.5 μM albendazole sulfoxide alone (ABZSO) and 10, 50, 100 and 200 μM Glb plus 2.5 μM ABZSO in combination. Parasites incubated in culture medium containing DMSO served as controls. Data are the mean ± S.D. of three independent experiments. *Statistically significant difference (<i>p</i> < 0.05) compared with the appropriate control (without drug or ABSZO alone). (B) Macroscopic damage in metacestodes exposed to glibenclamide. Control metacestodes (a) without morphological changes and metacestodes treated with 200 μM Glb for 5 days (b) showing increased permeability and collapsed germinal layer (circles). (C) Representative SEM images of control metacestodes (a, b) and treated with 200 μM glibenclamide for 5 days (c, d). (a, b) Control metacestode with an intact germinal layer; (c, d) Treated metacestode with altered germinal layer. Bars indicate: 50 μm in (a) and (c), and 20 μm in (b) and (d). (D) Intracystic concentrations of Glb from cysts incubated with 10, 50, 100 and 200 μM Glb in the experiment indicated in (A). *Statistically significant difference (<i>p</i> < 0.05) compared with control.</p

Therapeutic efficacy study in <i>E</i>. <i>granulosus</i> infected mice.

<p>(A) Box plots showing the comparative distribution of the weight (g) of cysts recovered from untreated mice (C) and treated with albendazole (ABZ, 5 mg/kg/d), glibenclamide (Glb, 5 mg/kg/d) and the combination of both drugs (Glb+ABZ) for 60 days. The weight of cysts was significantly decreased upon all treatments compared with the control (*<i>p</i> <0.05), but the decrease was more prominent in the groups receiving Glb alone or the combined treatment than that with ABZ alone (*<i>p</i> < 0.05). (B) Representative SEM images of hydatid cysts recovered from untreated mice (a, b) or treated with ABZ (c, d), Glb (e, f) and Glb+ABZ (g, h). Bars indicate: 20 μm in (a, c, e, g), and 10 μm in (b, d, f, h).</p

Bioactivity of gallic acid–conjugated silica nanoparticles against <i>Paenibacillus larvae</i> and their host, <i>Apis mellifera</i> honeybee

The aim of this work was to evaluate antimicrobial activity against Paenibacillus larvae and oral toxicity against workers and larvae of Apis mellifera of gallic acid (GA) and two nanohybrids of GA and silica. Also, the physicochemical, structural, and energetic properties of GA and the nanohybrids were determined through structure–activity relationship (SAR). The minimum inhibitory concentration (MIC) against P. larvae was determined. GA showed MIC values between 62.5 and 125 μg/ml, whereas the nanoparticle functionalized through the GA carboxylic moiety (NP2) showed the best antimicrobial activity with a MIC value of 23 μg GA/ml for four of the five isolates used. SAR analysis showed that electronegativity, chemical hardness, and dipolar moment are reliable estimators of the antimicrobial activity. NP2 showed the lowest toxicity against workers and was innocuous for bee larvae. Therefore, the nanohybrid NP2 was the best antibacterial and resulted in non-toxic against workers and larvae of honeybees, becoming a potentially effective and safe agent for the treatment of American Foulbrood disease.Facultad de IngenieríaCentro de Investigaciones ÓpticasFacultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada