Geosmin (trans-1,10-dimethyl-trans-9-decalol), an earthy-musty compound, has been identified in w... more Geosmin (trans-1,10-dimethyl-trans-9-decalol), an earthy-musty compound, has been identified in wines and in grape juice, in which its presence is highly detrimental to the aromatic quality. Geosmin has a biological origen, and the analysis of rotten grape microflora has been done on two grape varieties (Semillon, Cabernet Sauvignon) from six parcels of the Bordeaux region over 3 years (1999, 2000, 2001). Forty-three Penicillium-related species have been analyzed by gas chromatography–mass spectrometry (GC–MS) for their geosmin production. GC–MS analysis has demonstrated that the earthy odor was always correlated with the presence of geosmin. Phenotypic characterization of Penicillium spp. being ambiguous, a molecular characterization by rDNA internal transcribed spacer (ITS1) sequencing was performed for all strains. The results evidenced that all strains producing geosmin belonged to only one species, P. expansum, and that the other strains, not producing geosmin, belonged to three species: P. purpurogenum, P. thomii, and Talaromyces wortmanii.
In mammalian brain, dopaminergic (DA) cell bodies located in the ventral mesencephalon give rise ... more In mammalian brain, dopaminergic (DA) cell bodies located in the ventral mesencephalon give rise to meso-cortical, meso-limbic and meso-striatal systems. Among these, the meso-cortical DA pathway is particularly involved in the processing of emotional and cognitive responses. We demonstrate that the rat meso-cortical neurons specifically contain, in addition to DA, another transmitter, Neurotensin. If this co-localization exists in man, it may provide an anatomical substratum for the biological theory of schizophrenia as well as an indication that potential anti-psychotic drugs which act differentially on the DA ascending transmissions can be developed.
The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates a... more The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates among 106 E. coli non-O157 isolates was evaluated. The results showed atypical biochemical reactions but accurate identification at the species level and no unique biochemical profile numbers for E. coli O157, although these numbers were distinct from those of other serotypes.
Geosmin (trans-1,10-dimethyl-trans-9-decalol), an earthy-musty compound, has been identified in w... more Geosmin (trans-1,10-dimethyl-trans-9-decalol), an earthy-musty compound, has been identified in wines and in grape juice, in which its presence is highly detrimental to the aromatic quality. Geosmin has a biological origen, and the analysis of rotten grape microflora has been done on two grape varieties (Semillon, Cabernet Sauvignon) from six parcels of the Bordeaux region over 3 years (1999, 2000, 2001). Forty-three Penicillium-related species have been analyzed by gas chromatography–mass spectrometry (GC–MS) for their geosmin production. GC–MS analysis has demonstrated that the earthy odor was always correlated with the presence of geosmin. Phenotypic characterization of Penicillium spp. being ambiguous, a molecular characterization by rDNA internal transcribed spacer (ITS1) sequencing was performed for all strains. The results evidenced that all strains producing geosmin belonged to only one species, P. expansum, and that the other strains, not producing geosmin, belonged to three species: P. purpurogenum, P. thomii, and Talaromyces wortmanii.
In mammalian brain, dopaminergic (DA) cell bodies located in the ventral mesencephalon give rise ... more In mammalian brain, dopaminergic (DA) cell bodies located in the ventral mesencephalon give rise to meso-cortical, meso-limbic and meso-striatal systems. Among these, the meso-cortical DA pathway is particularly involved in the processing of emotional and cognitive responses. We demonstrate that the rat meso-cortical neurons specifically contain, in addition to DA, another transmitter, Neurotensin. If this co-localization exists in man, it may provide an anatomical substratum for the biological theory of schizophrenia as well as an indication that potential anti-psychotic drugs which act differentially on the DA ascending transmissions can be developed.
The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates a... more The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates among 106 E. coli non-O157 isolates was evaluated. The results showed atypical biochemical reactions but accurate identification at the species level and no unique biochemical profile numbers for E. coli O157, although these numbers were distinct from those of other serotypes.
Uploads
Papers by Denis Jacques