Fungi, Algae, Protozoa, and Multicellular Parasites

69 Pages·2009·4.36 MB·English

by  Terry W. Kupfer

Chapter 12: Fungi, Algae, Protozoa,
and Multicellular Parasites
Fungi
• Mycology = Study of Fungi
• All Fungi are chemoheterotrophs
– Require organic compounds for energy and carbon
– Can be aerobic (filamentous, bread mold) or
facultative anaerobes (yeast)
• Most of the 100,000 or more fungal species are
decomposers of dead plant material.
– Very few organisms other than fungi have enzymes that can
breakdown hard plant material (cellulose, lignin, pectins)
• Only about 200 species are implicated in human
disease.
Table 12.1
Table 12.2
Fungi: Vegetative Structures
(cells involved in catabolism and growth)
– Multicellular fungi, unlike yeast identification, are
identified on the basis of physical appearance,
including colony characteristics and reproductive
spores.
– 1. Molds and Flesh Fungi
• a. Thallus – long filaments of cells joined together
(called hyphae). Color, consistency of growth.
• b. Septa – cross-walls dividing the hyphae into distinct,
uninucleate cell like units (called septate hyphae)
• c. Vegetative hyphae – portion that is used to obtain
nutrients (growthbelow surface of media)
• d. Aerial hyphae – projects above media on which
fungus is growing and often contains spores
• e. Mycelium – filamentous mass
Figure 12.1 - Overview
Figure 12.2 - Overview
Fungi: Vegetative Structures
– 2. Yeasts
• Nonfilamentous unicellular fungi that are spherical or
oval
• Some divide by fission that can either be even or
uneven cell division (budding)
• Candida albicans – sometimes produces buds that fail
to detach into daughter cells and are called
pseudohyphae.
– These can resemble hyphae and penetrate deeper tissue.
• Colonies on agar can resemble bacterial colonies,
especially staph colonies.
• Can use oxygen or organic compounds as final electron
acceptor (can do aerobic respiration and fermentation)
Figure 12.3
Figure 21.17: Candidiasis - Overview.
Chlamydoconidia
Pseudohyphae
Blastoconidia
(a) Candida albicans (b) Oral candidiasis, or thrush
20 mm