355 research outputs found

    Identification of a non-host semiochemical from miniature pinscher, Canis lupus familiaris, that repels Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

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    It is already known that the beagle breed of domestic dogs produces semiochemicals capable of repelling the brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.). With a view to discovering new non-host semiochemicals as tick repellents, we compared the semiochemicals produced by a putative tick-resistant breed of dog, miniature pinscher, with known tick-resistant (beagle) and tick-susceptible (English cocker spaniel) breeds. Two non-host compounds produced by beagles, i.e. 2-hexanone and benzaldehyde, were shown to be present in volatile samples collected from all three breeds. Furthermore, two compounds, 6-methyl-5-hepten-2-one and 1,2,4-trimethylbenzene, were found in higher amounts in volatile samples collected from miniature pinscher dogs. The mean amounts of benzaldehyde, 2- hexanone and 1,2,4-trimethylbenzene were similar for beagles and miniature pinschers and higher than the means observed for cocker spaniels, whereas the mean amount of 6-methyl-5-hepten-2-one produced by miniature pinschers was significantly higher than for the other breeds of dogs. In Petri-dish assays with adult R. sanguineus, 6-methyl-5- hepten-2-one was repellent for all observation periods evaluated for the two highest concentrations (0.100 and 0.200 mg.cm-2). Our results support our hypothesis that miniature pinschers are a tick-resistant dog breed and agree with previous observations of miniature pinschers being the breed least parasitized by ticks. Furthermore, the non-host semiochemical 6-methyl-5-hepten-2-one has potential to be developed for use as a repellent for the protection of susceptible dogs from R. sanguineus s.l. ticks

    Gold Functionalized Supported Ionic Liquids Catalyst for CO Oxidation.

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    The present study tries to give an insight to the combination of the homogeneous and heterogeneous catalytic properties in a new class of materials. Well dispersed gold nanoparticles on an ionic liquid layer supported on a mineral carrier have been prepared. This work is concentrated on the characterizations and understanding of the interactions between all the components of the catalytic system. The application of the materials in the reaction of oxidation of carbon monoxide shows rather unexpected results¿a good catalytic activity completely independent of the temperature.L. Bobadilla acknowledges Junta de Andalucía (Project PDG-TEP01965). S. Ivanova and A. Penkova acknowledge MEC for their contracts Ramon y Cajal and Juan de la Cierva.Peer Reviewe

    Bioconversion of polyphenols and organic acids by gut microbiota of predigested Hibiscus sabdariffa L. calyces and Agave (A. tequilana Weber) fructans assessed in a dynamic in vitro model (TIM-2) of the human colon

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    The present work aimed at understanding gut microbiota bioconversion of phenolic compounds (PC) and organic acids in predigested Hibiscus sabdariffa (Hb) calyces and the mixture of Hb and Agave (Agave tequilana Weber) fructans (AF). With this purpose, dried Hb and Hb/AF were predigested with enzymatic treatment, and then fermented in a dynamic in vitro model of the human colon (TIM-2). After HPLC-ESI-QToF-MS analysis of samples taken at 0, 24, 48 and 72 h of fermentation, it was observed that hydroxycinnamic acids, flavanols, flavonols, and anthocyanins were mainly transformed into derivatives of hydroxyphenylpropionic, hydroxyphenylacetic and hydroxybenzoic acids. Moreover, organic acids, such as hydroxycitric and hibiscus acids, were formed along with unidentified lactones and reduced compounds. Interestingly, no differences were observed between microbial-derived metabolites formed after the fermentation of Hb and Hb/AF. In conclusion, colonic fermentation of polyphenol-rich Hb yields a wide range of microbial phenolic metabolites with potential effects on health.RMB and SGSA acknowledge to Science and Technology for Development Program (CYTED) through the Ibero-American Network of Underutilized Autonomous Foods (ALSUB-CYTED, 118RT0543). SGSA acknowledges CONACYT-Mexico for the sabbatical grant 260935. The Spanish Ministry of Science, Innovation and Universities (Project AGL2015-69986-R) is also acknowledged. This research has been made possible with the support of the Dutch Province of Limburg.Peer reviewe

    FOXO3 determines the accumulation of α-synuclein and controls the fate of dopaminergic neurons in the substantia nigra

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    Parkinson's disease (PD) is characterized by the selective degeneration of neuronal populations presumably due to pathogenic interactions between aging and predisposing factors such as increased levels of α-synuclein. Here, we genetically modulate the activity of the transcription factor Forkhead box protein O3 (FOXO3) in adult nigral dopaminergic neurons using viral vectors and explore how this determinant of longevity impacts on neuronal fate in normal and diseased conditions. We find that dopaminergic neurons are particularly vulnerable to changes in FOXO3 activity in the substantia nigra. While constitutive activation has proapoptotic effects leading to neuronal loss, inhibition of FOXO-mediated transcription by a dominant-negative competitor causes oxidative damage and is detrimental at high vector dose. To address the role of FOXO3 in PD, we modulate its activity in dopaminergic neurons overexpressing human α-synuclein. In this pathogenic condition, we find that FOXO inhibition has protective effects, suggesting that this transcription factor ultimately contributes to neuronal cell death. Nevertheless, mild FOXO3 activity also protects nigral neurons against the accumulation of human α-synuclein, albeit to a lesser extent. FOXO3 reduces the amount of α-synuclein present in the soluble protein fraction and promotes the coalescence of dense proteinase K-resistant aggregates, with an accumulation of autophagic vacuoles containing lipofuscin. Consistent with these in vivo observations, we find that FOXO3 controls autophagic flux in neuronal cells. Altogether, these results point to FOXO3 as an important determinant of neuronal survival in the substantia nigra, which may oppose α-synuclein accumulation and proteotoxicit

    Mechanical resistance, respiratory rate and the ethylene production of persimmon fruit 'Fuyu' during storage

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    The Fuyu persimmon fruit presents little literature review of mechanical properties and physiological behavior. In this paper the alteration of mechanical resistance to compression of persimmon fruit 'Fuyu' the respiratory behavior and the evolution of ethylene production during storage were evaluated. The fruits were harvested with two harvest indexes: Index 1, fruits with 15 to 20 days before the commercial index, and Index 2, known as the commercial index. The fruits were selected, packed (commercial carton boxes) and stored in two conservation conditions, with refrigeration (0 ± 1 ºC and 65 ± 1% RH) and without refrigeration (22 ± 3 ºC and 71 ± 6% RH). The Young's modulus of persimmon fruit decreases during the postharvest period independently of the conservation conditions. The Young's modulus varied between 3,695.3 and 968.2 kPa. The harvest index of persimmon fruit 'Fuyu' influenced the Young's modulus values during the storage. The persimmon fruit 'Fuyu' showed a respiratory pattern characteristic of climacteric fruits and exhibited a maximum ethylene evolution at the climacteric peak.El caqui 'Fuyu' presenta escasa revisión de literatura en lo que respecta a propiedades mecánicas y comportamiento fisiológico. En este trabajo fue evaluada la alteración de la resistencia mecánica a la compresión del caqui 'Fuyu', el comportamiento respiratorio y la evolución de la producción de etileno durante el almacenamiento. Las frutas fueron cosechadas con dos índices de cosecha: Índice 1, frutas cosechadas 15 a 20 días antes de la madurez comercial y, Índice 2, frutas cosechadas con madurez comercial. Las frutas fueron seleccionadas, empacadas en empaque comercial (caja de cartón) y almacenadas bajo dos condiciones de conservación: 1. Con refrigeración (0 ± 1 ºC y 65 ± 1% de HR; 2. Sin refrigeración (22 ± 3 ºC y 71 ± 6% de HR). El módulo de elasticidad del caqui disminuye durante el periodo postcosecha independiente de las condiciones de conservación. El módulo de elasticidad varió entre 3.695,3 y 968,2 kPa. El grado de madurez del caqui 'Fuyu' en el momento de la cosecha, influencia los valores del módulo de elasticidad durante el almacenamiento. El caqui 'Fuyu' presenta comportamiento respiratorio característico de fruto climatérico y el pico de evolución de etileno coincide con el pico climatérico.49850

    Bacterial genome adaptation to niches: Divergence of the potential virulence genes in three Burkholderia species of different survival strategies

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    BACKGROUND: Two closely related species Burkholderia mallei (Bm) and Burkholderia pseudomallei (Bp) are serious human health hazards and are potential bio-warfare agents, whereas another closely related species Burkholderia thailandensis (Bt) is a non-pathogenic saprophyte. To investigate the genomic factors resulting in such a dramatic difference, we first identified the Bm genes responsive to the mouse environment, and then examined the divergence of these genes in Bp and Bt. RESULTS: The genes down-expressed, which largely encode cell growth-related proteins, are conserved well in all three species, whereas those up-expressed, which include potential virulence genes, are less well conserved or absent notably in Bt. However, a substantial number of up-expressed genes is still conserved in Bt. Bm and Bp further diverged from each other in a small number of genes resulting from unit number changes in simple sequence repeats (ssr) in the homologs. CONCLUSION: Our data suggest that divergent evolution of a small set of genes, rather than acquisition or loss of pathogenic islands, is associated with the development of different life styles in these bacteria of similar genomic contents. Further divergence between Bm and Bp mediated by ssr changes may reflect different adaptive processes of Bm and Bp fine-tuning into their host environments

    Análisis comparativo de las características fisicoquímicas de la cascarilla de arroz.

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    En este estudio se hace un análisis comparativo de las principales propiedades fisicoquímicas de la cascarilla de arroz obtenida por investigaciones realizadas en las universidades de Canadá, California, RP China y de Ibagué Colombia, como punto de partida para la realización del proyecto de transformación de la biomasa arrocera en energía eléctrica y térmica. Se concluye que existe una igualdad entre los rengos de las características fisicoquímicas de la cascarilla de arroz para regiones tan distantes y diferentes como China, Canadá, Estados Unidos y Colombia; y que en ellas las temperaturas de oxidación alcanzada es del orden de 1200K, liberando alrededor del 67% del valor calórico en la etapa dominante de la combustión correspondiente a la combustión de los volátiles
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