Penicillium chrysogenum     

Creator of Penicillin "The Wonder Drug"                     *
                         Tom Volk - Mycology - University of Wisconsin, La Crosse
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The taxonomy below is based on similarities of DNA sequences as well as macroscopic characteristics.  Many of the phylogenetic trees are from the Taylor Lab's "Tree of Life project" which has great information regarding numerous organisms.

Domain: Eukarya
There are three groups within the broadest classification level of an organism. Along with all other eukaryotes, P. chrysogenum is in the group eukarya. This domain is characterized by organisms with membrane bound organelles, complex cells, and genetic material inside the nucleus.

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Lineage: Opisthokonta

There are eight major lineages within the domain eukarya.  Though these lineages are not one of true (King Phillip Came Over From Germany Sick) taxonomic levels, it doesn’t hurt to add a little more clarification. The opisthokonts include the mycrosporidians (organisms closely related to fungi), the fungi, the choanoflagellates (organisms closely related to animals), and the animals.  They are characterized by having flagellated, motile cells at some point as well as flattened mitochondrial cristae. This is the lineage which shows that fungi are more closely related to animals than plants.  Who would have thought?

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: Fungi

The kingdom fungi are classified as eukaryotic, heterotrophic organisms with cell walls made out of chitin.  Fungi can be either unicellular or multicellular and most can reproduce both asexually and sexually.

Phylum: Ascomycota or Not?

The groups within the kingdom fungi are separated via their sexual reproductive structures or lack there of.  Interestingly, P. chrysogenum does not show any mode of sexual reproduction.  Because of this, the fungus is put into a sort of “dumping group” called the deuteromycetes.  However, as I’m sure you noticed by the enlarged font above, I have classified it into the phylum ascomycota.  This was not a mistake.  Based on general morphology and DNA studies, it is safe to assume P. chrysogenum into the phylum ascomycota.  Until the sexual state is discovered, however, it will also belong to the dumping group (deuteromycetes).

Organisms within ascomycota bear their sexual spores (ascospores) within a sac-like structure called an ascus.   In fact, the ascomycota group is referred to as sac fungi.  Impress your friends by letting them know the Greek word “askos” literally means “sac.”  Again, this refers to the sexual reproductive structure called an ascus.  P. chrysogenum has yet to reveal this sexual structure.  However, like all other fungi within the ascomycota phylum, its asexual spores are in the form of conidia

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: Euascomycetes

The Phylum ascomycota is generally broken down into two main groups, the hemiascomycetes and the euascomycetes based on the presence or absence of an ascocarp.  The ascocarp is the name of the fruiting body which contains the sexual structures of the fungus.  In simpler terms, it’s a cluster of the sac-like sexual structures which were previously described.  Many fungi within this class also form lichens, a symbiotic relationship between a fungus and an algae or cyanobacteria.

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The order eurotiales is also known as the plectomycetes.  Fungi within this group tend to have thin walled asci which are scattered on the ascocarp.  The sexual structures tend to be spherical and closed (they are described as being “cleistothecium”).  Organisms within this order usually release their spores during decay or disintegration.  They are usually seen in the powdery mildew fungi. 

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Family: Trichocomaceae

The family trichocomaceae includes fungi which release their ascospores after the ascus is broken open.  The ascocarps (the fruiting body which contains multiple asci) form clusters of threads which have a fuzzy texture.  The phylogenetic tree below is based on these morphological characteristics as well as molecular characteristics, showing similar DNA structures.   

Stephanie Kitzmann - Family

Genus: Penicillium

Fungi within the genus Penicillium are filamentous and cotton-like in texture.  The colonies usually begin as a whitish color and, over time, produce green, blueish green, grey, yellow, or pink hues.  Organisms within Penicillium tend to have flask-shaped phialides (the structure which produces conidia). They are usually found in the air, soil, or decaying materials and are associated with infections as well as mycotoxins. Contrary to this, some fungi in this genus (such as Penicillium chrysogenum) have beneficial characteristics.  If you would like to see pictures of the characteristic paintbrush conidia, click here.  

There are many genera within the Trichocomaceae family, the phylogenetic tree below shows a few of the many relatives of the Penicillium genus on a molecular level, based on similar DNA sequences.

Stephanie Kitzmann - Genus

Species: P. chrysogenum

The species Penicillium chrysogenum is classified by its unique macroscopic morphology as well as microscopic features. P. chrysogenum is able to break down gram-positive (and not gram-negative) bacteria.  Because of this, it is known to produce the common drug penicillin which was a great help during World War II (more about this in Penicillin – The wonder drug).

Similar to the genus phylogenic tree, the number of species within Penicillium is way too high to list them all.  I have included some of the most common species below.  They, too, are placed in the specific species based on unique macroscopic and microscopic characteristics.
Stephanie Kitzmann - Species