Since the founding of ICPA in 1985, the members have collaborated on several round robin studies. The purpose of these studies has been to
Some of these studies are outlined below.
This publication contains a list of the species names accepted by members of ICPA for Aspergillus, Penicillium and similar anamorph and teleomorph genera. For each species, the correct authority, place of publication, and accession data for the holotype are included. Anamorph-teleomorph connections are given where they are known.
Pitt, J. I. and R. A. Samson. 1993.
Species names in current use in the Trichocomaceae (Fungi, Eurotiales). RegnumVegatabile 128:
12-57.
In: NCU-2. Names in Current Use in the Families Trichocomaceae, Cladoniaceae, Pinaceae, and Lemnaceae. Ed. W. Greuter. Koeltz Scientific Books, D-61453 Konigstein, Germany.
This publication can be ordered from Koeltz Scientific Books, D-61453 Konigstein, Germany or from Balogh Scientific Books USA at http://www.balogh.com/~balogh/catalogs.html
This study was published as: Pitt, J. I., M. A. Klich, G. P. Shaffer, R. H. Cruickshank, J. C. Frisvad, E. J. Mullaney, A. H. S. Onions, R. A. Samson and A. P. Williams. 1990. Differentiation of Penicillium glabrum from Penicillium spinulosum and other closely related species: An integrated taxonomic approach. System. Appl. Microbiol. 13: 304-309.
The abstract reads: "This study by the Subcommission on Penicillium and Aspergillus Systematics is concerned with the status of the closely related species Penicillium glabrum, P. spinulosum, P. purpurescens, and P. montanense. Thirty five isolates tentatively identified as these species were studied as unknowns by the eight members of the Subcommission. Characters studied included traditional morphology and gross physiology plus secondary metabolite profiles, isoenzyme patterns and DNA restriciton enzyme fragment length polymorphisms. The various approaches provided consistent identifications for most isolates, indicating that the four species could be separated satisfactorily and should be maintained. Statistical models based on morphological and gross physiological data indicated that five characters were of value in distinguishing the species. These were conidial wall texture, colony diameters on Czapek yeast extract agar and 25% glycerol nitrate agar, phialide width and vesicle diameter. Practical aspects of differentiating these species are also discussed."
This study, currently underway, is similar in approach and intent to the study of the P. spinulosum/glabrum project mentioned above. The first set of strains has been examined by ICPA members, but more strains need to be examined in order to complete the project.
The taxonomies of Penicillium and Aspergillus are heavily based on cultural characters. For this reason, correct identification requires careful standardization of media. Most of these media include malt and/or yeast extracts that differ from manufacturer to manufacturer and country to country. The inclusion of agar in solid media also prevents the media from being completely defined. Furthermore, the purity of the water used for preparing media varies from lab to lab.
It is now widely accepted that minor differences in extracts, agar and water can have profound effects on colony growth rates, the development of exudate and pigments, and conidial colours. We are presently engaged in small scale round robin studies intended to identify the sources of variation in the media. We ultimately hope to be able to suggest new additives that will eliminate the major sources of variation, so that better standardization of media will be possible all over the world.
Correct identification of Penicillium and Aspergillus species is critical. Because of a poor understanding of the microscopic features of these fungi, most biologists are reluctant to attempt to identify strains beyond genus. Taxonomic expertise on these fungi is scarce. As an aid for those who must identify species of these genera, ICPA will develop two sets of reference cultures. These can be ordered as sets from reputable culture collections at a reduced price, along with a booklet of standardized descriptions. The strains included have been selected because they are typical of their species, and taken as a whole, the sets demonstrate the taxonomic characters needed to identify most of the species in their respective genera. Because of the problems with medium standardization noted above, the colony descriptions and growth rates recorded for the specific strains in the booklet can be used as a calibration aid for media prepared in any laboratory.
The Aspergillus reference set is now available, and is described elsewhere on this home page. The reference set for Penicillium is still being developed.
This page last revised on July 3, 1996
