Transcript lecture notes-microbiology-4-Eucaryotes-yeast-mold

Eucaryotes
- Fungi: yeast and mold
- Algae
Eucaryotes
Fungi
• Fungi are heterotrophs which need to take
nutrients from the environment for living.
• They are larger than bacteria.
Fungi
Two major groups are yeast and mold.
Yeast
Yeasts are very important economically:
- Yeasts are responsible for fermentation of beer
and bread. (Saccharomyces cerevisiae)
- Ethanol production
- Wastewater treatment:
a mixed culture of yeasts Candida lipolytic
Candida tropicalis, and Yarrowia lipolytica grown
on hydrocarbons, or gas oil.
Yeast
Yeasts are very important economically:
- Yeasts and Bacterium xylinum cultures produce
Kombucha, fermented sweetened tea.
Yeasts: e.g.Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe
Yeast
http://www.sbs.utexas.edu/mycology/sza_images_SEM.htm
Eucaryotes-Fungi
Yeast is single-celled.
• Size: yeasts are 5 to 10 µm in diameter.
• Shape: spherical, cylindrical or oval.
• Reproduction: asexual and sexual.
Eucaryotes-Fungi
Yeasts
Reproduction: asexual and sexual.
• Asexual reproduction is by either budding
or fission.
Budding: a small bud cell forms on the cell, which
gradually enlarge and separate from the mother cells.
Most of the yeasts reproduce by budding.
Baker’s yeast, Saccharomyces cerevisiae.
Budding
Budding
Yeast Budding
http://www.sbs.utexas.edu/mycology/sza_images_SEM.htm
Yeast Reproduction
Asexual:
Fission: similar to budding but the cells grow to
certain size and divide into two equal cells.
Only a few yeast species are reproduced by
fission. e.g.Schizosaccharomyces pombe
Sexual: meiosis
Eucaryotes-Fungi
Molds
Molds are filamentous fungi and have a mycelial
structure.
Mycelium is highly branched system of tubes that contains
mobile cytoplasm with many nuclei.
Hypha is long, thin filaments on the mycelium.
Mold
• Molds are very important economically:
- mushroom farming is a large industry in many
countries.
Agaricus bisporus
http://en.wikipedia.org/wiki/Agaricus_bisporus
Mold
- Food industry
The mixed culture including Penicillium sp. for
cheese production.
Aspergillus niger for citric acid production.
- Antibiotics production.
Penicillium notatum
Eucaryotes-Fungi
Molds
Size:
When grow on solid surface, the filamentous form is
5-20 µm.
When grow in submerge culture, it can form aggregates
and pellets, 50 µm-1mm.
- Cause nutrient transfer problem in the pellet
Eucaryotes-Fungi
Mold Reproduction:
• Either by asexual or sexual means.
• Some molds form sexual spores which provide
resistance against heat, freezing, drying and some
chemical agents.
• Both asexual or sexual spores can germinate and form
new hyphae.
Eucaryote-Algae
Algae are usually unicellular or plantlike
multicellular organism.
• Like plants, most algae use the energy of sunlight to
make their own food, a process called photosynthesis.
Algae lack the roots, leaves, and other structures
typical of true plants.
• Algae contain chloroplast which is responsible for
photosynthesis.
• Unicellular algae are considered in Microbiology
E.g. Chlorophyta, Chrysophyta (brown, yellow-green
algae)
Eucaryote-Algae
• They are in the size of 10-30 µm.
• Algae can reproduce asexually or sexually. Many of
algae incorporate both sexual and asexual modes of
reproduction.
• Algae contain alginic acid and agar.
Virus
Not free-living organisms, obligate parasite of other living
cells.
• Size: 30-200nm.
• Can not capture or store free energy.
• Not functionally active except when inside their host
cells.
• Can do harm but also be useful
biotechnology tools (e.g. vaccines).
SARS Coronavirus virion
Virus
• Bacteriophage or phage: virus infecting
bacteria.
• (Virus: virus infecting eukaryotes)
• Virus reproduction:
- Virus contains genetic materials such as DNA
and RNA which is covered by a protein coat
called capsid.
- They can reproduce only by invading and
controlling other cells as they lack the cellular
machinery for self-reproduction.
Section Summary
• Organism cells are highly diverse in terms
of their adaptation to the living
environment:
Temperature, pH, oxygen, moisture,
nutrients
• Shapes (bacteria): Coccus, Bacillus and
Spirillum
Primary Classification
Cellular Organism
Have nuclear membrane and
membrane-bound organelles?
Yes
Eucaryotes
not free-living organisms
No
Procaryotes
Virus
Primary Classification
Cellular Organism
Have nuclear membrane and
membrane-bound organelles?
not free-living organisms
Yes
Eucaryotes
No
Procaryotes
Organelles:
Mitochondria: powerhouse
Endoplasmic reticulum: protein and lipid
synthesis
Lysosome: nutrient digestion enzymes
Golgi: protein secretion and modification
Vacuoles: food digestion, osmotic
regulation and waste product storage
Chloroplasts: photosynthesis
Virus
Fungi: yeast and mold
Algae:
(asexual or sexual reproduction)
Primary Classification
Cellular Organism
Have nuclear membrane and
membrane-bound organelles?
Yes
Eucaryotes
Cytoplasmic granules:
- Ribosome: protein synthesis
- Storage granules: source of key
metabolites, including
polysaccharides, lipids and sulfur
granules.
- Capsule
- Pili
- Flagella
not free-living organisms
No
Procaryotes
Virus
Eubacteria: gram-positive, gramnegative, non-gram, actinomycetes
and cyanobacteria
Archaebactria: methanogen
Halogen
thermoacidophiles
Mostly asexual reproduction
Primary Classification
Cellular Organism
Have nuclear membrane and
membrane-bound organelles?
not free-living organisms
Yes
Eucaryotes
No
Procaryotes
Virus: reproduce
Asexual reproduction in the host cell
Fungi: yeast, mold
Eubacteria:
Archaebateria:
Algae:
Gram-positive bacteria
Gram-negative bacteria
Non-gram bacteria
Actinomycetes
Cynaobacteria
methanogen
Halogen
Thermoacidophiles
Reproduction: asexual or
sexual