Morphological Characteristics, Extracellular and Intracellular Protein and Enzyme Patterns of Five Aspergillus Species
Katarina Jernejc* and Aleksa Cimerman
National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
Article history:
Received March 23, 2001
Accepted November 8, 2001
Key words:
morphology, isozymes, taxonomy, Aspergilli
Summary:
Six biotechnologically interesting Aspergilli, four of which were isolated lately and included in the culture collection of National Institute of Chemistry MZKI, were examined morphologically and biochemically. Since species may no longer produce typical morphological, structures, some nonmorphological methods in classification were used. Based on both macroscopic and microscopic observations, using an identification key, individual isolates were classified within the genus Aspergillus, belonging to three subgenera, four sections, five species and two A. niger strains. In different Aspergilli differences in the amounts of total lipids, sterols and fatty acids were observed, but they were not significant enough to distinguish between species. Intracellular protein profiles did not differ between the two A. niger strains, neither were they different in A. oryzae and A. flavus, both belonging to the section Flavi. Differences appeared between sections Nigri and Flavi, belonging to the subgenera Circumdati, but the largest differences were observed on the subgenus level. Enzyme analyses clearly differ among fungi examined on the basis of the number of isozyme bands and their molecular weights. Isocitrate dehydrogenase revealed one band, whereas acid phosphatases two or three bands, in all examined fungi. Malate dehydrogenases showed one and lactate dehydrogenases one band or two isozyme bands. Differences on the subgenus level, with the results obtained, were greatest, but differences at strain level could also be seen.
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