1. The Eukaryotes: Fungi, Algae, Protozoa, and Helminths12
The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

2. Fungi Eukaryotic Cells contain a nucleus
Aerobic or facultatively anaerobic
Makes ATP (energy) through respiration if oxygen is present, but can go through fermentation if oxygen is not present
Chemoheterotrophic
Must break down and absorb organic compounds for energy and carbon
Most are decomposers

3. Types of fungi: Molds
The thallus (body) of a mold consists of long filament of cells joined together called hyphae
Grow by elongating at the tips
Every part of a hypha (singular) is capable of growing
Most fungus grown in labs is grown from fragments
When conditions are favorable for growth, hyphae
will grow into a mass called a mycelium
Figure 12.2

4. Types of Hypha Vegetative hypha
The portion of a hypha that obtains nutrients
Aerial hypha
Portion of hypha concerned with reproduction
Projects above the surface the mold is growing on
Usually produce reproductive spores

5. Types of Fungi: Yeasts Nonfilamentous, unicellular fungi
Typically spherical or oval in shape
Two types:
Budding yeasts - divide unevenly
A protuberance known as a bud forms on the
surface of a parent cell and elongates, eventually
breaking off after the nucleus divides
Some yeast buds fails to detach and instead form a small chain of cells called a pseudohypha
Ex: Candida albicans attaches to human skin cells but require pseudohypha to get to deeper tissue
Figure 12.3

7. Fission yeasts
Divide evenly to produce two new identical cells
Entire parent cell elongates and splits
Similar to bacterial fission

8. Dimorphism - The ability to take on two different forms
Can grow as either yeasts or molds
Usually temperature dependent
histoplasma capsulatum below is yeast like at 37 C (left), but mold like below 36 C (right)
Can be dependent on presence or lack of CO2
Figure 12.4

9. Fungal life cycle
Fungi reproduce both sexually and asexually through the use of spores
Formed from aerial hyphae
Asexual spores are formed by hyphae of one organism
When they germinate, they produce genetically identical organisms to the parent

10. Types of asexual spores Conidiospore
Uni or multicellular spore that is not enclosed in a sac
Sporangiospore – formed within a sac
A single sac
can contain
hundreds of
spores

11. Sexual spores result from fusion of the nuclei from two strands of the same species
Results in organisms with characteristics of both parental strands
Three phases
Plasmogamy: nuclues of donor cell penetrates cytoplasm of recipient cell
Karyogamy: two nuclei fuse
Meiosis: nucleus divides to form spores

13. The difference between bacteria and fungi
Fungi are adapted to environments that would be hostile to most bacteria
Grow better in environments that are too acidic for bacterial growth
Can grow in high sugar or salt concentrations
Can grow on substances with low moisture content
Require less nitrogen
Can metabolize complex carbs

14. Fungi Phyla The following three phyla are telemorphs
Can reproduce both sexually and asexually
Zygomycota
Conjugation fungi
Reproduction occurs when hypha of two fungi merge together to form spores instead of using a reproductive structure such as a mushroom cap
Have coenocytic hyphae
Multinuclear
Occurs when there is mitosis but not cytokinesis

15. Zygomycete Life Cycle Zygospores are created when two fungal hypha
fuse – sexual reproduction
A sporangium will form from the zygospore which produces hundreds of identical spores to be released for new fungi to grow – asexual repro.
Figure 12.6

16. Ascomycota
Sac fungi
Septated hyphae
The hypha have a cell wall-like septa within to make it look like it is multicellular
Some are anamorphs – have lost the ability to reproduce sexually

17. Ascomycete Life Cycle
Asexual repro: spores are usually conidia that are produced in long chains and can freely detach
Sexual repro: ascopores result from the fusion of two nuclei
Produced in the ascus (saclike structure)
Figure 12.7

18. Basidiomycota
Club fungi
Septate hyphae
Include fungi that produces mushrooms

19. Basidiomycete Life Cycle
Asexual repro: portion of hypha breaks off and grows into a new hypha/mycelium
Sexual repro: basidiospores are produced on the basidium
In cap mushrooms, these are located on the gills
Figure 12.8

21. Fungal diseases Mycosis: any fungal infection
Generally chronic (long-lasting) because of the slow growth of fungi
Classified into 5 groups
Based on the degree of tissue involvement and mode of entry into host
Many are difficult to treat because of the close evolutionary relationship between fungal and animal cells

22. Systemic mycoses Fungal infections deep within the body
Can affect a number of tissues and organs
Not restricted to any one region of the body
Usually caused by fungi found in soil
Transmitted through inhalation of spores
Typically begin in the lungs and spread to other tissue
Not contagious
Ex: histoplasmosis(aka cave disease)

23. Disseminated histoplasmosis: has spread beyond the lungs and is life threatening at this point

24. Subcutaneous mycoses Fungal infections beneath the skin
Caused by saprophytic fungi (decomposers – break down dead/decaying matter) that live in soil and on vegetation
Ex: sporotrichosis
Common in gardeners and farmers that causes lesions on the hands (or wherever comes in contact)
Infection occurs when spores or
part of the mycelium enter a puncture
wound on skin

25. Cutaneous mycoses Aka dermatomycoses
Infect the epidermis, hair and nails
Caused by dermatophytes
Secrete keratinase, an enzyme that breaks down keratin
Transmitted human to human or animal to human by direct contact with infected hair or epidermal cells
Ex: athlete’s foot and ringworm

27. Superficial mycoses
Infections localized along hair shafts and in surface epidermal cells
Most prevalent in tropical climates
Very similar to cutaneous
Difference is the localization – does not spread around the body

28. Opportunistic mycoses
Caused by normal microbes or fungi that typically are harmless
Become pathogenic in a host with a compromised immune system
Examples:
Pneumocystis - most common life-threatening infection in AIDS patients
Stachybotrys – normally grows on cellulose of dead plants, can cause fatal pulmonary hemorrhage in infants when found in homes