TY - JOUR
T1 - Classification of species in the genus Penicillium by Curie point pyrolysis/mass spectrometry followed by multivariate analysis and artificial neural networks.
AU - Nilsson, Torben
AU - Bassani, Maria R.
AU - Larsen, Thomas Ostenfeld
AU - Montanarella, Luca
PY - 1996/12
Y1 - 1996/12
N2 - Curie point pyrolysis/mass spectrometry of Penicillium species was performed with 530 degrees C Curie point foils. The mass spectra were submitted to principal component analysis, canonical variates analysis and hierarchical cluster analysis, producing a final dendrogram by the use of average linkage clustering. By this approach a successful classification of the species Penicillium italicum, P. expansum and P. digitatum originating from fruits was obtained. Isolates of the same species grouped together in the dendrogram, while the different species were distinguished. Also when grown on two different agar media, replicates of the same species grouped together. Likewise, a satisfactory classification was achieved by multivariate analysis of the data for various isolates of the cheese-associated fungi Aspergillus versicolor, P. discolor, P. roqueforti, P. solitum, P. verrucosum, P. commune and P. palitans. However, some difficulties appeared in distinguishing the closely related species P. commune and P. palitans. Such difficulties became greater on including more isolates and limiting the analysis to five of the species. The use of back-propagation artificial neural networks, in contrast, resulted in a correct classification in all cases. Thus, it is concluded that Curie point pyrolysis/mass spectrometry is useful in chemotaxonomic studies of the closely related species in the genus Penicillium.
AB - Curie point pyrolysis/mass spectrometry of Penicillium species was performed with 530 degrees C Curie point foils. The mass spectra were submitted to principal component analysis, canonical variates analysis and hierarchical cluster analysis, producing a final dendrogram by the use of average linkage clustering. By this approach a successful classification of the species Penicillium italicum, P. expansum and P. digitatum originating from fruits was obtained. Isolates of the same species grouped together in the dendrogram, while the different species were distinguished. Also when grown on two different agar media, replicates of the same species grouped together. Likewise, a satisfactory classification was achieved by multivariate analysis of the data for various isolates of the cheese-associated fungi Aspergillus versicolor, P. discolor, P. roqueforti, P. solitum, P. verrucosum, P. commune and P. palitans. However, some difficulties appeared in distinguishing the closely related species P. commune and P. palitans. Such difficulties became greater on including more isolates and limiting the analysis to five of the species. The use of back-propagation artificial neural networks, in contrast, resulted in a correct classification in all cases. Thus, it is concluded that Curie point pyrolysis/mass spectrometry is useful in chemotaxonomic studies of the closely related species in the genus Penicillium.
KW - artificial neural networks
KW - cluster analysis
KW - Curie point pyrolysis mass spectrometry
KW - multivariate analysis
KW - Penicillium
U2 - 10.1002/(SICI)1096-9888(199612)31:12<1422::AID-JMS442>3.0.CO;2-5
DO - 10.1002/(SICI)1096-9888(199612)31:12<1422::AID-JMS442>3.0.CO;2-5
M3 - Journal article
SN - 1076-5174
VL - 31
SP - 1422
EP - 1428
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
IS - 12
ER -