Part 3 of 3
On this third and final stop on our tour of the kingdom of fungi we will examine the Zygomycetes. These organisms are found all over the world in all kinds of environments. Most are not pathogenic to humans. They normally feed on dead or decaying plant and animal material, however a few species of Zygomycetes are parasitic- found living at the expense of another organism. Other species may be symbiotic, living with another organism in mutual benefit.
One of the most notorious of fungi is included in this phylum. It is Rhizopus stolonifer, the common “black bread mold”. This organism spreads over the surface of bread and buries its hyphae deep into the surface in order to absorb nutrients. Another popular Zygomycete is Rhizopus oryzae, which used to make sake- the rice wine of Asia. Other members of this phylum are: Absidia, Apophysomyces, Cokeromyces, Cunninghamella, Mucor, Rhizomucor, Saksenaea, Syncephalastrum, Mortierella, Basidiobolus, and Conidiobolus.
Unlike Basidiomycetes and Ascomycetes, Zygomycetes often lack septated mycelia. Septa are formed mainly for the removal of old or damaged hyphae. Some other unique characteristics are related to their mechanism of reproduction. Like Basidiomycetes and Ascomycetes, Zygomycetes may reproduce sexually or asexually. Sexual reproduction is done through the use of hapliod mating hyphae, from which zygospores are formed.
Even though the sexual method of reproduction, obviously, contributed to the name of the phylum, most Zygomycetes utilize asexual means for their reproduction. This is done in stalked sporangia which hold numerous spores.
Fig. 1 Zygospore
Fig, 2 Sporangia
Fungi is included in this category disperse their spores similar to Ascomycetes and Basidiomycetes. Transmission can be done by wet or dry. That means they have the ability to use both air currents and water droplets. Other methods include mechanical transport, such as movement while settled on the fur of animals. Spores from Zygomycetes are often quite large so they settle on surfaces quite easily. For this reason they normally are not collected at high concentrations in air samples, but never doubt their presence in the home.