The fungal world: Basic traits	Zygomycetes	Ascomycetes	Basidomycetes
Chytrids	Slime molds (P)	Oomycota	1. Deuteromycetes 2. Lichens

Ascomycetes:

I. Subdivision Ascomycotina are commonly known as the Sac Fungi, due to their sac-like appendage that holds the spores.

• There are over 30,000+ species ranging from one-celled yeasts to fairly large morels and truffels as well as some of the common black molds, green molds, the powdery mildews, the cup fungi.
  
• Although most are considered in a positive light for their ability to ferment some of our favorite beverages, to leaven our bread and to add a distinctive ping to some cheeses, other are more notorioius as disease promoting organisms ( chestnut blight, Dutch Elm disease, forming rots of a number of fruit trees, powdery mildews).
  
• The mycelium, when present, is composed of septate hyphae that are multinucleate with pores within the septata. Image from: http://www.pacificcoast.net/%7Emycolog/CHAP4a.htm

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There are at least three different ascoma forms: from the open apothecia structure to the enclosed cleistotheica. The latter is thought to be an adaptation to fungi that grow beneth surfaces where dispersal by wind would be prohibited. In this case, an insect or motile vector may carry this packet of spores to another location where the spores can be released.

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• This class has a dikaryon stage in the ascogenous hyphae.

The typical life cycle is as follows: Before the2 uninucleate hyphae of different gentoypes touch each other, the different hyphoae will form either a female or male gametangium. The female gametangium is called the ascogonium and the male the antheridium. The ascogonium sends out a thin growth called the trichogyne to the male through which nucei can migrate. The resulting structure now has 2 types of nuclei, and forms hyhae that are n+n or dikaryon. These n+n hyphae form the fruiting structure or body.

As the fruiting structure forms, the tip of each hyphae forms a hook. The cell below the hyphal tip enlarges and the 2 nuclei in it fuse to form a zygote ( a true 2N nucleus). This undergoes meiosis to form 8 haploid nuclei each which becomes a spore.

II. Class Ascomycetes includes a number of subclasses, only a few of which we have the time to cover:

* Subclass Hemiascomycetidae Order Endomycetales (Yeasts):

Saccharomyces: These single-celled simple organisms have been studied by geneticists as well as brewers for many years. According to your text only 10% of the genes as yet sequenced bear a resemblance to known genes of other organisms.

Although they don't produce large ascocarps as we'll later see in the morels, they do produce ascospores with asci. The basic body structure is as indicated below. They can reproduce either asexually by budding ( or sexually forming ascospores.

taken from slides in lab.

* Subclass Plectomycetidae Order: Eurotiales (Blue molds):

Aspergilli are filamentous fungi of the ascomycete class. The scientific name is derived from the Latin words; aspergillum which is a device used to sprinkle holy water..

In the diagram below you can see the formation of spores at the tip of a hyphal extension called a condiophore. These spores are from asexual derivation and are called condia.

The condia formation animation comes from the link given below; this is a really great site all on fungi.. visit when you have time!

from:http://www.pacificcoast.net/%7Emycolog/CHAP4a.htm

Aspergillus flavus grows on peanuts and many other substrates, producing a mycotoxin called aflatoxin, which contaminates food and causes liver damage even at very low concentrations.  It is the most potent carcinogen (cancer-inducing) substance known. If you see greenish-blue mold growing in your frig a good guess would be colonies of Penicillium italicum

Aspergillus:

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taken fromslides in lab

• Order Erysiphales (Powdery mildews)
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• Order Pezizales (Morels and saddle fungi): certainly not all the peziza are delious but many are prized for their excellent flavor...

Morchella esculenta	Deer truffles.... Order Tuberales (Truffles):Tuber aestivum