Conversion of the Mycotoxin Patulin to the Less Toxic Desoxypatulinic Acid by the Biocontrol Yeast Rhodosporidium kratochvilovae Strain LS11

Se describe en este artículo 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

Negative emotional state shortens the duration of the chewing sequence

International audienceAlthough the effect of the quality of dental state on the quality of chewing has been studied extensively, almost nothing is known about the repercussions of emotional states on masticatory muscles activity observed during chewing. The objective of this study was to evaluate the effects of positive and negative emotional states on the electromyographic (EMG) activity during food ingestion. With this aim in view, we employed an association of pictures and sounds taken from the international affective picture system (IAPS) and the international affective digitized sound (IADS) system was used. These effects which varied in valence neutral to pleasant or unpleasant were used to investigate masticator muscle activity in 26 young adults exposed to these stimuli during the mastication of cheese. The emotional state was evaluated by recording variations in cardiac rhythm. There were fewer chewing bursts and less muscle activity during unpleasant stimuli compared to pleasant and neutral stimuli, resulting in a shortened chewing sequence

Poor Mastication Could Result in Poor Nutrition: The Effects of Age on Oral Functions and Consequences on Nutrition

Research and Review Studies:Chapter IPoor Mastication Could Result in Poor Nutrition: The Effects of Age on Oral Functions and Consequences on Nutritio

Variation in human masseter and temporalis muscle activity related to food texture during free and side-imposed mastication

International audienc

Tongue-mandible coupling movements during saliva swallowing

International audienc

Is the tongue position influenced by the palatal vault dimensions?

International audienc