Mycology (World of Microbiology and Immunology)
Mycology is the study of fungi, including molds and yeasts. The study of mycology encompasses a huge number of microorganisms. Indeed, just considering molds, the estimates of the number of species ranges from the tens of thousands to over 300,000.
Fungi are eukaryotic microorganisms (eukaryotes have their nucleic material contained within a membrane), which can produce new daughter fungi by a process similar to bacteria, where the nuclear material replicates and then the cell splits to form two daughter cells, or via sexual reproduction, where nuclear material from two fungi are mixed together and the daughter cells inherit material from both parents. Growth of fungi can occur either by the budding off of the new daughter cells from the parent or by the extension of the branch (or hyphae) of a fungus.
The study of fungi can take varied forms. Discovery of new fungi and their grouping with the existing fungi is one aspect of mycology. Unraveling the chemical nature of the fungal survival and growth is another aspect of mycology. For example, some fungi produce antibiotics such as penicillin as part of their defensive strategies. This aspect of mycology has proved to be extremely important for human health. The adverse effects of fungi on human health and plants constitutes yet another aspect of mycology. Still another aspect of mycology, which can encompass some of the preceding, is concerned with the economic impact, beneficial or not, of fungi. For example, those fungi that are edible or which produce antibiotics have a tremendous positive economic impact, whereas fungi that cause damage to agricultural plants exact a negative economic toll.
Some mycologists (scientists who study fungi) conduct extensive research into the origin of fungi. The discovery of fossilized fungi that resemble those from the four major groups of modern fungi in rocks that date back 36010 million years indicate that fungi were already well-established and diversifying even before other forms of life had made the transition from the sea to the land.
Mycology has resulted in the classification of fungi into four divisions. These divisions are the Chytridiomycota, Zygomycota (which include the bread molds such as Neurospora), Ascomycota (which include yeasts), and the Basidiomycota. Lichens do not fit this classification, as lichens are not single-celled fungi. Rather, they are a symbiotic association (an association that is beneficial for both participants) between a fungus and an alga.
The health-oriented aspect of mycology is important, particularly as the danger of fungal infections, especially to those whose immune system is compromised, has been recognized since the identification of acquired immunodeficiency syndrome in the 1970s.
For example, in those whose immune systems are functioning properly, an infection with the mold known as Aspergillus can produce a mild allergic type of reaction. However, in those people whose immune systems are not operating efficiently, the mold can grow in the lungs, and can produce a serious infection called bronchopulmonary aspergillosis. As well, a more invasive infection via the bloodstream can result in mold growth in the eye, heart, kidneys, and the skin. The invasive infection can be lethal.
Mycologists are becoming increasingly involved in the remediation of buildings. The so-called "sick building syndrome" is often due to the growth of fungi, particularly molds, in the insulation of buildings. The growth of the molds including Cladosporium, Penicilium, Alternaria, Aspergillus, and Mucor can produce allergic reactions ranging from inconvenient to debilitating to building users.
See also Candidiasis; Economic uses and benefits of microorganisms; Slime molds