Fungi in the thirdphyla, phylum Ascomycota, are themost abundant as more than 65.000 species belong here. Their trademark is theirstructural component, the ascus, which is a sac-like unit, harboring eightascospores, in which sexual and asexual reproduction occurs. The formation ofthis component arises when a spore lands on a suitable substrate, after which ahaploid mycelium is formed. From this mycelium, asexual structures or sexualstructures can be produced.
The female sexual structure is called ascogonium, whilethe male sexual structure is an antheridium. Initiation of sexual reproductionoccurs when male and female sexual components merge, which forms a singleorganism with separate nuclei, called an ascogonoius hyphae. Following this, theirnuclei merge at the end of the ascogonius hyphae and they go through a round ofmeiosis. Next to meiosis, mitosis happens, leading to the formation of a totalof eight mature ascospores– ready to be released. Due to the sheer amount of species, phylumAscomycota, exert both a positive and negative effect on the human condition.
Beneficial species such as Penicilliumnotatum and Saccharomyces cerevisiaecontribute to our health and or ability to produce beverages, while maligneffects are seen by species of the Aspergillus genus who can cause respiratorydisease, decay food, synthetize carcinogenic toxins in nuts etc. TheAspergillus genus will be investigated extensively later in this paper. Thefourth phyla, Basidiomycata, are nextto Ascomycota the most abundant phyla with more than 30.000 separate speciesand because of this abundance, their diversity is large and plentiful.
Thisphylum encompasses the largest and most complex fungi, in which most species sharea common structural component coined basidium. The basidium is a club shaped structure, in which meiosis takes placeand where basidiospores are synthesized, often located on fruiting bodies suchas mushrooms. Basidiomycotareproduce asexually by producing spores or by a mechanism called budding, inwhich an extension of a cell is separated into its own cell. Sexualreproduction happens when haploid hyphae meet and fuse, often followed by thetransfer of a nuclei from each parent hyphae to the other, which reproducesmitotic, thus, creating a dikaryotic mycelium. From dikaryotic mycelium a fruiting bodyarises, by hyphae, who communicate and create different components.
Some createthe stalk, other the gills of the fruiting body. The tips of the hyphae whichconstitutes the gills is the basidium and when these swell, nuclei are fusedand a bit after 4 basidiospores are formed, which will then be ready to bereleased. Basidiomycota play an important role in ecosystems, as they achievenutrient by breaking down decomposing organic material, unfortunately they alsobreak down wood, which have negative economical consequences.