Search results for "toxin"

Discoordinate regulation of different K channels in cultured rat skeletal muscle by nerve growth factor

1999

We investigated the effects of nerve growth factor (NGF) on expression of K+ channels in cultured skeletal muscle. The channels studied were (1) charybdotoxin (ChTx)-sensitive channels by using a polyclonal antibody raised in rabbits against ChTx, (2) Kv1.5 voltage-sensitive channels, and (3) apamin-sensitive (afterhyperpolarization) channels. Crude homogenates were prepared from cultures made from limb muscles of 1-2-day-old rat pups for identification of ChTx-sensitive and Kv1.5 channels by Western blotting techniques. Apamin-sensitive K+ channels were studied by measurement of specific [125I]-apamin binding by whole cell preparations. ChTx-sensitive channels display a fusion-related incr…

Comparative effects of carrier proteins on vaccine-induced immune response

2011

The efficacy of vaccines against major encapsulated bacterial pathogens -Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type b (Hib) - has been significantly enhanced by conjugating the respective polysaccharides with different carrier proteins: diphtheria toxoid; non-toxic cross-reactive material of diphtheria toxin(197), tetanus toxoid, N. meningitidis outer membrane protein, and non-typeable H. influenzae-derived protein D. Hib, meningococcal, and pneumococcal conjugate vaccines have shown good safety and immunogenicity profiles regardless of the carrier protein used, although data are conflicting as to which carrier protein is the most immunogenic. Coadmini…

Bioactive metabolites from the endophytic fungus Ampelomyces sp. isolated from the medicinal plant Urospermum picroides

2007

Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their 1H and 13C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds …

Phenguignardic acid and guignardic acid, phytotoxic secondary metabolites from Guignardia bidwellii.

2012

Bioactivity-guided isolation led to the identification of phenguignardic acid (2), a new phytotoxic secondary metabolite from submerged cultures of grape black rot fungus, Guignardia bidwellii. The compound is structurally related to guignardic acid (1), a dioxolanone moiety-containing metabolite isolated previously from Guignardia species. However, in contrast to guignardic acid, which is presumably synthesized from deamination products of valine and phenylalanine, the biochemical precursor for the biosynthesis of the new phytotoxin appears to be exclusively phenylalanine. Guignardic acid was also found in extracts of cultures from Guignardia bidwellii. The phytotoxic activities of both co…

Panton-Valentine leukocidin positive sequence type 80 methicillin-resistant Staphylococcus aureus carrying a staphylococcal cassette chromosome mec t…

2012

Methicillin-resistant Staphylococcus aureus (MRSA) is a major antimicrobial drug-resistant pathogen causing serious infections. It was first detected in healthcare settings, but in recent years it has also become disseminated in the community. Children and young adults are most susceptible to infection by community-acquired (CA) MRSA strains. In this study 25 MRSA isolates implicated in infections of neonates and children admitted to an Algiers hospital during an 18 month period were characterized by molecular methods including staphylococcal cassette chromosome (SCC) mec typing, PCR amplification of pvl genes, pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). F…

Effect of triterpenoids on the inflammation induced by protein kinase C activators, neuronally acting irritants and other agents.

2000

In order to establish the mode of the anti-inflammatory activity of triterpenoids, 11 naturally occurring compounds were assayed on mouse ear oedema induced by the protein kinase C activators, mezerein, 12-O-tetradecanoylphorbol-13-acetate (TPA), two 12-deoxyphorbol-13-monoesters (13-tetradecanoate (DPT) and 13-phenylacetate (DPP)) and bryostatin 1, and by resiniferatoxin, xylene and arachidonic acid. The effects on bradykinin-induced paw oedema and on the rat skin inflammation caused by hydrogen peroxide were also examined. The oedema induced by mezerein and DPT was reduced to different extents by the triterpenoids administered epicutaneously (0.5 mg per ear). Against DPT-induced oedema, l…

Morphological changes in adherent cells induced by Clostridium difficile toxins.

1991

Risk assessment of mycotoxins in cereals = Evaluación del riesgo de micotoxinas en cereales

2015

Las micotoxinas son un grupo de sustancias producidas por diferentes especies de hongos filamentosos. La presencia de micotoxinas en los alimentos constituye un problema de salud pública a nivel mundial. En la Unión Europea se han establecido contenidos máximos en materias primas y alimentos para 14 micotoxinas, consideradas de mayor relevancia para la salud del consumidor. En la actualidad se está prestando atención a otros grupos de micotoxinas menos estudiadas, como las micotoxinas emergentes de Fusarium, entre las que se encuentran la beauvericina, las eniatinas y la fusaproliferina. Se trata de micotoxinas de creciente interés en el campo de la seguridad alimentaria por presentar una e…

Efectos de las micotoxinas beauvericina y metabolitos de la zearalenona in silico e in vitro en células de neuroblastoma humano SH-SY5Y

2021

Las especies de hongos del género Fusarium sintetizan una amplia gama de micotoxinas muy variada química y estructuralmente. La zearalenona (ZEA) constituye uno de los grupos más grandes de micotoxinas producidas por Fusarium, que son los principales patógenos de los cereales. En esta Tesis Doctoral se ha realizado, en primer lugar, un estudio in silico del perfil metabolómico de la ZEA y sus derivados, α-zearalenol (α-ZEL) y β-zeralenol (β-ZEL), y de la predicción de sus efectos tóxicos. También se ha realizado un estudio de todos los productos de metabolización de las reacciones de fase I y II. En segundo lugar, debido a una característica común de las especies de Fusarium asociada a sint…

Toxicological Study in vitro, in vivo and Transcriptomic of Mycotoxins. Estudio Toxicológico in vitro, in vivo y Transcriptómico de Micotoxinas

2018

Las micotoxinas, producidas por el metabolismo secundario de hongos filamentosos, se consideran contaminantes comunes de alimentos y piensos y constituyen una preocupación en el ámbito de la seguridad alimentaria. Se han estudiado los efectos tóxicos y mecanismos de acción de las micotoxinas emergentes Beauvericina (BEA) y Eniatinas (ENs) mediante ensayos in vitro en células Jurkat, in vivo en rata Wistar y transcriptómicos por secuenciación del ARN; así como la presencia de multi-micotoxinas en alimentos, piensos y muestras biológicas. Las revisiones realizadas ponen de manifiesto que (i) la investigación in vivo de fusarotoxinas se basa principalmente en estudios de toxicidad subaguda y s…