Buscador

Encontrado(s) 2167389 resultado(s)
Encontrada(s) 216739 página(s)

Mechanisms underlying the enhancement of toxicity caused by the coincubation of zinc oxide and copper nanoparticles in a fish hepatoma cell line

  • Hernández-Moreno, D.
  • Li, L.
  • Connolly, M.
  • Conde, E.
  • Fernández, M.
  • Schuster, M.
  • Navas, J. M.
  • Fernández-Cruz, M. L.
Ecosystems are exposed to a wide variety of individual substances, including at the nano-scale; and the potential adverse effects of their interactions are an increasing concern. The purpose of the present study was to determine whether zinc oxide nanoparticles (ZnONPs) at a no-observed-effect concentration modulate the cytotoxicity of copper nanoparticles (CuNPs) in the fish hepatoma cell line PLHC-1 after 48 h of exposure and the contribution of the released ions to these effects. Cells were exposed to 50-nm CuNPs (0.39–25.0 µg/mL), alone or in combination with ZnONPs (25 nm or 100 nm), at 6.25 µg/mL. Cells were exposed to suspensions of NPs or to their supernatants, as well as to their combinations. The effects on cell viability were assessed through cytotoxicity assays. Changes in cell morphology and metal internalization were also evaluated. The cytotoxicity exerted by CuNPs was enhanced in the presence of nontoxic concentrations of ZnONPs. On the contrary, Zn ions protected the cell line from the CuNP toxicity, this effect being related to an increase in the intracellular levels of Zn. This increase of metal was not observed in cells exposed to both ZnONPs and CuNPs, even when they were visualized inside the cell. The results indicated that the internalization of ZnONPs, but not the Zn ions, was responsible for the enhanced toxicity of the CuNPs. Environ Toxicol Chem 2016;352562–2570. © 2016 SETAC. © 2016 SETAC
Proyecto:


Pregnancy-associated changes in plasma concentration of the endocrine disruptor di(2-ethylhexyl) phthalate in a sheep model

  • Herreros, M. A.
  • Gonzalez-Bulnes, A.
  • Iñigo-Nuñez, S.
  • Letelier, C.
  • Contreras-Solis, I.
  • Ros-Rodriguez, J. M.
  • Encinas, T.
The plasticizer di(2-ethylhexyl)phthalate (DEHP), used for producing polyvinyl chloride (PVC), acts as an endocrine disruptor with toxic effects on reproductive and developmental processes. Exposure to DEHP in humans is mainly by environment and food. Thus, our aim was to determine plasma levels in livestock animals using the ewe (Ovis aries) as a model. In a first trial, 150 samples from ewes of different ages (2 to 7 yr) and reproductive status (pregnant and nonpregnant) were analyzed by high-performance liquid chromatography (HPLC). DEHP was detected in 34.7% of the samples, with a mean level of 0.45 ± 0.01 μg/mL (range, 0.05 to 2.81 μg/mL). The percentage of nonpregnant animals with DEHP traces was higher in animals older than 4 yr (n = 66, 37.9%) than in younger animals (n = 69, 17.4%; P < 0.05), although the mean levels in ewes with residues were similar (0.16 ± 0.01 vs. 0.16 ± 0.02 μg/mL). All the pregnant ewes (n = 15) showed presence of DEHP, with higher plasma levels than that in nonpregnant females (1.42 ± 0.18 vs. 0.16 ± 0.01 μg/mL; P < 0.0001). For confirming the effect of pregnancy on mobilization of DEHP from body fat, 101 ewes of the same age were sampled in a second trial at a different farm. The percentage of animals with DEHP traces was higher in pregnant ewes (n = 32, 71.9%; P < 0.005) than in nonpregnant ewes (n = 37, 35.1%) or in ewes that recently gave birth (n = 32, 21.9%), although mean levels were similar (0.42 ± 0.02, 0.33 ± 0.02, and 0.34 ± 0.05 μg/mL, respectively). In conclusion, current results indicate a high incidence of ewes reared in the field showing accumulation of phthalates; percentage of animals with presence of DEHP increases with age, due to an extended period of exposure, but mainly during pregnancy, due to the mobilization of body reserves. © 2010 Elsevier Inc. All rights reserved.
Proyecto:


Commercial income and capital of hunting An application to forest estates in Andalucía

  • Herruzo, A. C.
  • Martínez-Jauregui, M.
  • Carranza, J.
  • Campos, P.
This paper presents and applies an experimental agroforestry accounting system (AAS) to measure the commercial income and capital of hunting activities in a large territorial area. This application goes beyond the conventional system of national agriculture and forestry accounts. The methodology developed allows the independent valuation of both environmental and manufactured capital which in turn allows the disaggregation of hunting income and other economic indicators by type of capital. The spatial distribution of these economic indicators can also be provided. Results show positive current total capital income but residual manufactured capital income current losses. An underlying economic rationale explaining this phenomenon is offered. © 2016 Elsevier B.V.
Proyecto:


Industrial potential of lipoxygenases

  • Heshof, R.
  • de Graaff, L. H.
  • Villaverde, J. J.
  • Silvestre, A. J. D.
  • Haarmann, T.
  • Dalsgaard, T. K.
  • Buchert, J.
Lipoxygenases (LOXs) are iron- or manganese-containing oxidative enzymes found in plants, animals, bacteria and fungi. LOXs catalyze the oxidation of polyunsaturated fatty acids to the corresponding highly reactive hydroperoxides. Production of hydroperoxides by LOX can be exploited in different applications such as in bleaching of colored components, modification of lipids originating from different raw materials, production of lipid derived chemicals and production of aroma compounds. Most application research has been carried out using soybean LOX, but currently the use of microbial LOXs has also been reported. Development of LOX composition with high activity by heterologous expression in suitable production hosts would enable full exploitation of the potential of LOX derived reactions in different applications. Here, we review the biological role of LOXs, their heterologous production, as well as potential use in different applications. LOXs may fulfill an important role in the design of processes that are far more environmental friendly than currently used chemical reactions. Difficulties in screening for the optimal enzymes and producing LOX enzymes in sufficient amounts prevent large-scale application so far. With this review, we summarize current knowledge of LOX enzymes and the way in which they can be produced and applied. © 2015 Informa Healthcare USA, Inc.
Proyecto:


Effect of a bacteriocin-producing Lactococcus lactis strain and high-pressure treatment on the esterase activity and free fatty acids in Hispánico cheese

  • Ávila, M.
  • Calzada, J.
  • Garde, S.
  • Nuñez, M.
The effect of milk inoculation with a bacteriocin-producing (BP) culture and of high-pressure (HP) treatment of 15-day-old Hispánico cheeses (400 MPa, 5 min, 10 °C), separately or combined, on the release of intracellular esterases and cheese lipolysis was investigated. Esterase activity and free fatty acids (FFAs) content increased during ripening of Hispánico cheese and palmitic, oleic and stearic acids being the most abundant FFAs. On day 15, the highest esterase activity was recorded for HP-treated BP cheese. The activity for HP-untreated BP cheese was the next highest. No difference in the activities was found between HP-treated and untreated cheeses made without BP culture. Total FFAs on day 15 were at a lower concentration in BP cheeses than in cheeses made without BP culture, probably due to the lower pH values of the former. The rate of total FFA accumulation from day 15 to day 50 was higher in BP cheeses (31.1-32.1% increase) than in cheeses made without BP culture (19.3-21.7% increase). The highest total FFA concentration on day 50 (612 mg kg-1) was found for HP-untreated cheese made without BP culture. © 2007 Elsevier Ltd. All rights reserved.
Proyecto:


A haplotype regression approach for genetic evaluation using sequences from the 1000 bull genomes project

  • Lakhssassi, K.
  • González-Recio, O.
Haplotypes from sequencing data may improve the prediction accuracy in genomic evaluations as haplotypes are in stronger linkage disequilibrium with quantitative trait loci than markers from SNP chips. This study focuses first, on the creation of haplotypes in a population sample of 450 Holstein animals, with full-sequence data from the 1000 bull genomes project; and second, on incorporating them into the whole genome prediction model. In total, 38,319,258 SNPs (and indels) from Next Generation Sequencing were included in the analysis. After filtering variants with minor allele frequency (MAF< 0.025) 13,912,326 SNPs were available for the haplotypes extraction with findhap.f90. The number of SNPs in the haploblocks was on average 924 SNP (166,552 bp). Unique haplotypes were around 97% in all chromosomes and were ignored leaving 153,428 haplotypes. Estimated haplotypes had a large contribution to the total variance of genomic estimated breeding values for kilogram of protein, Global Type Index, Somatic Cell Score and Days Open (between 32 and 99.9%). Haploblocks containing haplotypes with large effects were selected by filtering for each trait, haplotypes whose effect was larger/lower than the mean plus/minus 3 times the standard deviation (SD) and 1 SD above the mean of the haplotypes effect distribution. Results showed that filtering by 3 SD would not be enough to capture a large proportion of genetic variance, whereas filtering by 1 SD could be useful but model convergence should be considered. Additionally, sequence haplotypes were able to capture additional genetic variance to the polygenic effect for traits undergoing lower selection intensity like fertility and health traits. © 2017 INIA.
Proyecto:


Expression of swine transmissible gastroenteritis virus envelope antigens on the surface of infected cells epitopes externally exposed

  • Laviada, M. D.
  • Videgain, S. P.
  • Moreno, L.
  • Alonso, F.
  • Enjuanes, L.
  • Escribano, J. M.
The peplomer protein (S) and the transmembrane protein (M) of transmissible gastroenteritis virus (TGEV) of swine were identified by iodination and serologically on the surface of infected cells. Of a total of 4 monoclonal antibodies (mAb) directed against four antigenic sites of S protein (Correa et al.;1988), 3 specific for sites A, B and D attached to the plasma membrane of infected cells, as disclosed by indirect immunofluorescence and by complement-mediated cytolysis. Four of the mAbs assayed were specific for the viral protein M and two of them gave plasma membrane immunofluorescence and mediated cytolysis in the presence of complement. The viral nucleoprotein N could not be demonstrated on the surface of infected cells either by iodination or employing 3 mAbs against this protein. Finally, a time course infection experiment demonstrated that S and M proteins were expressed on the surface of infected cells at 4 h after infection, before infective virus was released from infected cells. © 1990.
Proyecto:


Glucogenic supply increases ovulation rate by modifying follicle recruitment and subsequent development of preovulatory follicles without effects on ghrelin secretion

  • Letelier, C.
  • Mallo, F.
  • Encinas, T.
  • Ros, J. M.
  • Gonzalez-Bulnes, A.
This study determined the effects of short-term energy inputs on ghrelin secretion and possible links with changes in the follicle population or the ovulation rate. Oestrous cycle was synchronized in 16 Manchega sheep using progestagen sponges and cloprostenol. Half of the animals were treated from days 0 to 4 by the oral administration, twice daily, of 200 ml of a glucogenic mixture containing 70% of glycerol, 20% of 1,2-propanediol and 10% of water; the control group received 200 ml water. The mean (± S.E.M.) plasma glucose increased immediately after the first administration (3.9±0.3 vs 3.0±0.1 mmol/l in control group, P<0.05), remaining statistically different during the treatment. However, plasma ghrelin levels were similar in both groups. On the other hand, the results indicated that short-term energy inputs modify ovulation rate (1.9±0.1 vs 1.3±0.2 in control group, P<0.05) by increasing the number of follicles able to be selected to ovulate during the period of treatment (≥ 4 mm in size; 5.9±0.6 vs 4.3±0.4 at day 2, P<0.05). After sponge withdrawal, the number of these follicles decreased throughout follicular phase (5.8±0.8 to 1.5±0.4, P<0.0005) while the number of large follicles increased (≥ 6 mm in size; 0.8±0.4 to 2.0±0.3, P<0.05); this would indicate an active growth of preovulatory follicles that were not found in the control group. Thus, the increases of ovulation rate by high-energy inputs would be caused by an enhancement in the developmental competence of preovulatory follicles. © 2008 Society for Reproduction and Fertility.
Proyecto:


Sperm characteristics and heterologous in vitro fertilisation capacity of Iberian ibex (Capra pyrenaica) epididymal sperm, frozen in the presence of the enzymatic antioxidant catalase

  • López-Saucedo, J.
  • Paramio, M. T.
  • Fierro, R.
  • Izquierdo, D.
  • Catalá, M. G.
  • Coloma, M. A.
  • Toledano-Díaz, A.
  • López-Sebastián, A.
  • Santiago-Moreno, J.
The aim of this work was to evaluate the protective effect of catalase (CAT) on frozen/thawed ibex epididymal sperm recovered post mortem, and to detect any harmful effect this might have on sperm fertilisation capacity. Epididymal spermatozoa were diluted using a Tris-citric acid-glucose medium (TCG) composed of 3.8% Tris (w/v), 2.2% citric acid (w/v), 0.6% glucose (w/v), 5% glycerol (v/v), and 6% egg yolk (v/v). Sperm masses from the right epididymis were diluted with TCG medium, while those from the left were diluted with TCG medium supplemented with 200. IU/mL CAT. Heterologous in vitro fertilisation (IVF) was used to assess the fertilisation capacity of this sperm. The addition of CAT to the extender did not improve frozen/thawed sperm variables. Moreover, a reduced fertilisation capacity was detected sperm diluted with TCG provided 25.5% 2PN zygotes, while just 13.2% was recorded for that diluted with TCG-CAT (P<. 0.01). The percentage of cleaved embryos at 48. hpi was higher (P<. 0.01) with the TCG sperm than with the TCG-CAT sperm (16.7% vs. 7.6%). The use of 200. IU/mL CAT as an additive cannot, therefore, be recommended for the preservation of ibex epididymal sperm. Other antioxidants should, however, be tested in both this and related wild mountain ungulates. © 2014 Elsevier Inc.
Proyecto:


Understanding Rift Valley fever Contributions of animal models to disease characterization and control

  • Lorenzo, G.
  • López-Gil, E.
  • Warimwe, G. M.
  • Brun, A.
Rift Valley fever (RVF) is a mosquito-borne viral zoonosis with devastating health impacts in domestic ruminants and humans. Effective vaccines and accurate disease diagnostic tools are key components in the control of RVF. Animal models reproducing infection with RVF virus are of upmost importance in the development of these disease control tools. Rodent infection models are currently used in the initial steps of vaccine development and for the study of virus induced pathology. Translation of data obtained in these animal models to target species (ruminants and humans) is highly desirable but does not always occur. Small ruminants and non-human primates have been used for pathogenesis and transmission studies, and for testing the efficacy of vaccines and therapeutic antiviral compounds. However, the molecular mechanisms of the immune response elicited by RVF virus infection or vaccination are still poorly understood. The paucity of data in this area offers opportunities for new research activities and programs. This review summarizes our current understanding with respect to immunity and pathogenesis of RVF in animal models with a particular emphasis on small ruminants and non-human primates, including recent experimental infection data in sheep. © 2015 Elsevier Ltd.
Proyecto:


Buscador avanzado