CH 12 - Eukaryotic Microbes

Eukaryotic Microbe

How it differs from Bacteria:

• has a nucleus and membrane bound organelles

• cell wall (if present) DOES NOT have PEPTIDOGLYCAN

• may be haploid or diploid

• may have asexual or sexual reproduction

• may be unicellular or multicellular

Groups of Microscopic Eukaryotes

• Algae

• Fungi

• Protozoans

Some additional multicellular organisms that deal with transmission of human disease:

• Arthropods

• Worms (Helminths)

MYCOLOGY

• the study of FUNGI

• includes yeasts, molds, and mushrooms

Yeast

• single celled fungi, reproduce by Budding (blastospores)

Mushrooms

• reproductive structures of certain fungi

FUNGI

Can be represented through the following terms:

• Heterotrophs

• Saprotrophs

• Parasites

• Mycosis

Saprotrophs (saprophytes)

• use nutrients from dead or decaying organic matter

• major decomposers of organic material, important for nutrient cycling

Parasites

• absorb nutrients from living tissues

Mycosis

• disease caused by pathogenic fungi

Fungi Structure

1) Cell walls contain chitin and glucan: Glucan synthesis is a target of antifungal medications

2) Lack chloroplasts, energy storage is glycogen

3) Membranes contain ergosterol: a target of antifungal medications

Applications of Fungi

• food industry

• biofuel

• beverage

• medicine & biotechnology

• agriculture

• environmental management

• commodities

• pulp, paper, textile industry

Fungi (cont.)

• most grow as molds, some grow only as yeast

• fungi that transition between two morphologies are termed DIMORPHIC

Molds

• thread-like filaments called hyphae

Dimorphism

• pathogenic dimorphic fungi are often SINGLE CELLED (yeast-like) at 37 C and FILAMENTOUS (mold-like) at 25 C

Mycelium Structure

Fungi (cont.)

• typically non-motile, hyphae can grow toward food