21 research outputs found
Déterminisme héréditaire du caractère « crête pâle » chez la poule
International audienc
Conversion of the Mycotoxin Patulin to the Less Toxic Desoxypatulinic Acid by the Biocontrol Yeast Rhodosporidium kratochvilovae Strain LS11
Se describe en este artÃculo el descubrimiento de la degradación de la micotoxina patulina por una levaduraThe infection of stored apples by the fungus Penicillium expansum causes the contamination of fruits and fruit-derived
products with the mycotoxin patulin, which is a major issue in food safety. Fungal attack can be prevented by beneficial
microorganisms, so-called biocontrol agents. Previous time-course thin layer chromatography analyses showed that the aerobic
incubation of patulin with the biocontrol yeast Rhodosporidium kratochvilovae strain LS11 leads to the disappearance of the
mycotoxin spot and the parallel emergence of two new spots, one of which disappears over time. In this work, we analyzed the
biodegradation of patulin effected by LS11 through HPLC. The more stable of the two compounds was purified and characterized by
nuclear magnetic resonance as desoxypatulinic acid, whose formation was also quantitated in patulin degradation experiments. After
R. kratochvilovae LS11 had been incubated in the presence of 13C-labeled patulin, label was traced to desoxypatulinic acid, thus
proving that this compound derives from the metabolization of patulin by the yeast. Desoxypatulinic acid was much less toxic than
patulin to human lymphocytes and, in contrast to patulin, did not react in vitro with the thiol-bearing tripeptide glutathione. The
lower toxicity of desoxypatulinic acid is proposed to be a consequence of the hydrolysis of the lactone ring and the loss of functional
groups that react with thiol groups. The formation of desoxypatulinic acid from patulin represents a novel biodegradation pathway
that is also a detoxification process
Bioaccumulation and ecotoxicity of carbon nanotubes
Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review indicate that CNT do not cross biological barriers readily. When internalized, only a minimal fraction of CNT translocate into organism body compartments. The reported CNT toxicity depends on exposure conditions, model organism, CNT-type, dispersion state and concentration. In the ecotoxicological tests, the aquatic organisms were generally found to be more sensitive than terrestrial organisms. Invertebrates were more sensitive than vertebrates. Single-walled CNT were found to be more toxic than double-/multi-walled CNT. Generally, the effect concentrations documented in literature were above current modeled average environmental concentrations. Measurement data are needed for estimation of environmental no-effect concentrations. Future studies with benchmark materials are needed to generate comparable results. Studies have to include better characterization of the starting materials, of the dispersions and of the biological fate, to obtain better knowledge of the exposure/effect relationships
CHEMICAL AND AETHIOLOGICAL OBSERVATIONS ON KERATOCONJUNCTIVITIS SINUSITISES IN BIRDS
International audienc