Search results for "toxin"
showing 10 items of 1434 documents
Estrategias alternativas para la bioconjugación de ocratoxina A y su aplicación en inmunodiagnóstico alimentario
2020
Ocratoxina A (OTA) es un metabolito secundario producido por hongos del género Aspergillus y Penicillium. Esta micotoxina puede encontrarse en una gran variedad de alimentos, entre los que se encuentran cereales, café o vino. OTA es un potente carcinógeno en roedores, motivo por el que se encuentra clasificado en el grupo 2B (posible carcinógeno para humanos) por la Agencia Internacional de Investigación sobre el Cáncer. Con el objetivo de reducir la exposición de los consumidores a esta micotoxina, la Comisión Europea ha establecido concentraciones máximas en varias matrices alimentarias, siendo este límite de 2 µg/L en el caso de vino y zumo de uva. Entre las diferentes técnicas analítica…
The effects of dietary fumonisin B1 on growth and physiology of rainbow trout (Oncorhynchus mykiss)
2016
Kalanrehuissa on perinteisesti luotettu kalajauhoon ja -öljyyn rehujen pääasiallisina proteiinin- ja energianlähteinä. Näitä raaka-aineita on nykyään alettu korvata kasviperäisillä ainesosilla niiden edullisemman hinnan ja helpomman saatavuuden vuoksi, esimerkiksi maissilla, vehnällä ja soijalla. Pilaantuneen kasviperäisen raaka-aineen mukana rehuun pääsee haitallisia mykotoksiineja. Mykotoksiinit ovat homesienten sekundäärisiä metaboliatuotteita, joita ne pääasiassa tuottavat kilpailuun muita homeita vastaan, ja joiden on havaittu aiheuttavan kasvun heikentymistä ja sairauksia monilla eri kotieläimillä, mutta niiden vaikutuksista kaloihin tiedetään varsin vähän. Yksi yleisimmistä mykotoksi…
Reducción de la contaminación por hongos toxigénicos y micotoxinas en alimentos mediante el uso de isotiocianatos
2019
El crecimiento de hongos es una de las causas más habituales del deterioro de los alimentos. Productos como los cereales, el pan y sus derivados son especialmente susceptibles ser contaminados con hongos toxigénicos y/o micotoxinas, lo que supone un problema de seguridad alimentaria. Por ello en la presente Tesis Doctoral se han estudiado la presencia de micotoxinas en 60 muestras de masas de pizza refrigeradas y el riesgo de exposición de la población a estos compuestos. Se detectaron aflatoxinas (AFs), zearalenona (ZEA), eniatinas (ENs) y beauvericina (BEA) en el 50, 100, 100 y 3 % respectivamente. Aunque el riesgo de exposición fue moderado, el 12 % de las muestras superaba los límites m…
Estudio de la reducción química y biológica de hongos y micotoxinas en pan
2017
El deterioro de los alimentos causado por los hongos que producen micotoxinas representa un problema importante en seguridad alimentaria. Los cereales en grano y sus productos derivados, como el pan, frecuentemente están contaminados con hongos micotoxigénicos. Es por ello que en la presente Tesis Doctoral se han estudiado la presencia de 17 micotoxinas en 80 muestras de pan de molde y el riesgo de exposición de la población a estos compuestos. Aflatoxinas (AFs), zearalenona (ZEA) y eniatinas (ENs) han sido detectadas respectivamente en el 20%, 65% y 96% de las muestras de pan analizadas. La presencia de dichas micotoxinas y, sobre todo, de las muestras en las que las AFs y la ZEA superan e…
First evidence of antimicrobial activity of neurotoxin 2 from anemonia sulcata (Cnidaria)
2014
International audience; We investigated the antibacterial activity of Anemonia sulcata (Cnidaria, Anthozoa) tentacle and body acidic extracts. Biochemical purification consisted of first step on solid phase Sep-Pak C8 column followed by several HPLC runs on C18 column using different conditions. Anti-Micrococcus lysodeikticus activity has been detected in 40 % acetonitrile fractions. The resulting purified molecule from tentacles had a molecular mass determined by MALDI-TOF mass spectrum of 4946,299 Da and has been completely sequenced. Its aa sequence revealed identity with the Neurotoxin 2 (ATX-II), a Na + channel blocking toxins. Consequently, ATX-II appeared to display a dual role as to…
eIF2α confers cellular tolerance to S. aureus α-toxin
2015
We report on the role of conserved stress-response pathways for cellular tolerance to a pore forming toxin. First, we observed that small molecular weight inhibitors including of eIF2α-phosphatase, jun-N-terminal kinase (JNK), and PI3-kinase sensitized normal mouse embryonal fibroblasts (MEFs) to the small pore forming S. aureus α-toxin. Sensitization depended on expression of mADAM10, the murine ortholog of a proposed high-affinity receptor for α-toxin in human cells. Similarly, eIF2α (S51A/S51A) MEFs, which harbor an Ala knock-in mutation at the regulated Ser51 phosphorylation site of eukaryotic translation initiation factor 2α, were hyper-sensitive to α-toxin. Inhibition of translation w…
Virulence factor rtx in Legionella pneumophila, evidence suggesting it is a modular multifunctional protein
2008
Abstract Background The repeats in toxin (Rtx) are an important pathogenicity factor involved in host cells invasion of Legionella pneumophila and other pathogenic bacteria. Its role in escaping the host immune system and cytotoxic activity is well known. Its repeated motives and modularity make Rtx a multifunctional factor in pathogenicity. Results The comparative analysis of rtx gene among 6 strains of L. pneumophila showed modularity in their structures. Among compared genomes, the N-terminal region of the protein presents highly dissimilar repeats with functionally similar domains. On the contrary, the C-terminal region is maintained with a fashionable modular configuration, which gives…
Temperature effects explain continental scale distribution of cyanobacterial toxins
2018
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect…
Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculoviru…
2015
Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae…
Binding analysis of Bacillus thuringiensis Cry1 proteins in the sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae).
2015
Sugarcane borer (Diatraea saccharalis, F.) is an important corn pest in South America and United States. The aim of the present study was to analyze the susceptibility and binding interactions of three Cry1A proteins and Cry1Fa in a Brazilian D. saccharalis population. The results showed that Cry1Ab was the most active, followed by Cry1Ac, Cry1Fa and Cry1Aa. All Cry1-biotinylated proteins tested bound specifically to the D. saccharalis brush border membrane vesicles (BBMV). Heterologous competition assays showed shared binding sites for all Cry1A proteins and another one shared by Cry1Fa and Cry1Ab. Thus, pyramiding Cry1Aa/Cry1Ac and Cry1F proteins would be a recommended strategy for managi…