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Applied Microbiology

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Title: Applied Microbiology


1
Applied Microbiology
  • 4th lecture Chapter 5

2
Eukaryotic Cells
The History of Eukaryotes
They first appeared approximately 2 billion years
ago. Evidence suggests evolution from
prokaryotic organisms by symbiosis. Organelles
originated from procaryotic cells trapped inside
them. -gt Endosymbiosis
3
Endosymbiosis
Algae
4
Eukaryotic Cells
Eukaryotic Organisms in Microbiology
5
Eukaryotic Cells
Form and Function of the Eukaryotic Cell
6
Eukaryotic Cells
Form and Function of the Eukaryotic Cell
7
Eukaryotic Cells
External Structures
  • Locomotor appendages
  • Flagella
  • - long, sheathed cylinder containing microtubules
    in a 92 arrangement
  • - covered by an extension of the cell membrane
  • - 10X thicker than procaryotic flagella
  • - function in motility
  • Cilia
  • - similar in overall structure to flagella, but
    shorter and more numerous
  • - found only on a single group of protozoa and
    certain animal cells
  • - function in motility, feeding and filtering

8
Eukaryotic Cells
External Structures
Flagella
Cross section -gt arrangement of proteins
Longitudinal section
Locomotor pattern
9
Eukaryotic Cells
External Structures
Cilia
Structure
Locomotion
10
Eukaryotic Cells
External Structures
  • Glycocalyx
  • an outermost boundary that comes into direct
    contact with
  • environment
  • - usually composed of polysaccharides
  • - appears as a network of fibers, a slime layer
    or a capsule
  • - functions in adherence, protection, and signal
    reception
  • - beneath the glycocalyx
  • -gt Fungi and most algae have a thick, rigid cell
    wall.
  • -gt Protozoa, a few algae, and all animal cells
    lack a cell wall and
  • have only a membrane.

11
Eukaryotic Cells
External Boundary Structures
  • Cell wall
  • rigid, provides structural support and shape
  • Fungi have thick inner layer of polysaccharide
    fibers
  • composed of chitin or cellulose and a thin
    layer of mixed
  • glycans.
  • algae varies in chemical composition
    substances
  • commonly found include cellulose, pectin,
    mannans, silicon
  • dioxide, and calcium carbonate

12
Eukaryotic Cells
External Boundary Structures
  • Cytoplasmic (cell) membrane
  • typical bilayer of phospholipids and proteins
  • sterols confer stability
  • serves as selectively permeable barrier in
    transport
  • Eucaryotic cells also contain membrane-bound
    organelles
  • that account for 60-80 of their volume.

13
Eukaryotic Cells
Internal Structures
  • Nucleus
  • compact sphere, most prominent organelle of
    eukaryotic
  • cell
  • nuclear envelope composed of two parallel
    membranes
  • separated by a narrow space and is perforated
    with pores
  • - contains chromosomes
  • nucleolus dark area for rRNA synthesis and
    ribosome
  • assembly

14
Eukaryotic Cells
Internal Structures
  • Nucleus

15
Eukaryotic Cells
Internal Structures
  • Nucleus
  • Cell division
  • -gt Mitosis
  • Replication of Chromosomes
  • Separation of replicated
  • Chromosomes into 2 cells

16
Eukaryotic Cells
Internal Structures
  • Endoplasmic reticulum two types
  • Rough endoplasmic reticulum (RER) originates
    from the outer membrane of the nuclear envelop
    and extends in a continuous network through
    cytoplasm rough due to ribosomes proteins
    synthesized and shunted into the ER for packaging
    and transport first step in secretory pathway
  • Smooth endoplasmic reticulum (SER) closed
    tubular network without ribosomes functions in
    nutrient processing, synthesis and storage of
    lipids, etc.

17
Eukaryotic Cells
Internal Structures
Rough Endoplasmic reticulum
18
Eukaryotic Cells
Internal Structures
  • Golgi apparatus
  • consists of a stack of flattened sacs called
    cisternae
  • closely associated with ER
  • Transitional vesicles from the ER containing
    proteins go to the
  • Golgi apparatus for modification and
    maturation.
  • Condensing vesicles transport proteins to
    organelles or
  • secretory proteins to the outside.

19
Eukaryotic Cells
Internal Structures
Golgi -gt The secretary pathway
20
Eukaryotic Cells
Internal Structures
  • Lysosomes
  • vesicles containing enzymes that originate from
    Golgi apparatus
  • involved in intracellular digestion of food
    particles and in
  • protection against invading microbes

21
Eukaryotic Cells
Internal Structures
Lysosomes -gt involved in Phagocytosis Process
of uptake of substances from outside the cell
22
Eukaryotic Cells
Internal Structures
  • Mitochondria
  • consists of an outer membrane and an inner
    membrane with folds called
  • cristae
  • - Cristae hold the enzymes and electron carriers
    of aerobic respiration.
  • - divide independently of cell
  • - contain DNA and procaryotic ribosomes
  • - function in energy production

23
Eukaryotic Cells
Internal Structures
  • Chloroplast
  • found in algae and plant cells
  • outer membrane covers inner membrane folded into
    sacs, thylakoids,
  • stacked into grana
  • larger than mitochondria
  • contain photosynthetic pigments
  • convert the energy of sunlight into chemical
    energy through
  • photosynthesis
  • - primary producers of organic nutrients for
    other organisms

24
Eukaryotic Cells
Internal Structures
Chloroplast
25
Eukaryotic Cells
Internal Structures
  • Ribosomes
  • composed of rRNA and proteins
  • 40S and 60S subunits form 80S ribosomes
  • larger than procaryotic ribosomes (70S)
  • - function in protein synthesis

30S
50S
70S
26
Eukaryotic Cells
Internal Structures
  • Cytoskeleton
  • flexible framework of proteins, microfilaments
    and microtubules
  • form network throughout cytoplasm
  • involved in movement of cytoplasm, amoeboid
    movement,
  • transport, and structural support

27
Eukaryotic Cells
Eukaryotic Microbes
-gt Fungi -gt Algae -gt Protozoa -gt Parasitic
worms
28
Eukaryotic Cells
Kingdom Fungi
  • 100,000 species divided into 2 groups
  • -gt macroscopic fungi (mushrooms, puffballs, gill
    fungi)
  • -gt microscopic fungi (molds, yeasts)
  • Majority are unicellular or colonial a few have
    cellular specialization

29
Microscopic fungi
Slime mold
Yeast
30
Macroscopic fungi
31
Eukaryotic Cells
Microscopic fungi
  • Exist in two morphologies
  • -gt yeast round ovoid shape, asexual
    reproduction, unicellular
  • -gt hyphae long filamentous fungi or molds
  • Some exist in either form dimorphic
  • mold-like at low temperature, yeast like at 37
    degrees C, characteristic of some pathogenic molds

32
Eukaryotic Cells
Macroscopic and Microscopic view
Mixed cultures of mold
Hyphal structures
Structural types of hyphae
33
Eukaryotic Cells
Macroscopic and Microscopic view
Morphology of yeast
34
Eukaryotic Cells
Fungal Nutrition
-gt All are heterotrophic -gt Majority are
harmless saprobes living off dead plants and
animals -gt Some are parasites, living on the
tissues of other organisms, mycoses fungal
infections -gt Growth temperature 20o-40oC -gt
Extremely widespread distribution in many habitats
35
Eukaryotic Cells
Fungal Nutrition
Mycellium growing on raspberries
Fungus growing on skin
36
Eukaryotic Cells
Fungal Organization
  • -gt Most grow in loose associations or colonies
  • -gt Yeast soft, uniform texture and appearance
  • -gt Filamentous fungi mass of hyphae called
    mycelium cottony,
  • hairy, or velvety texture
  • - hyphae may be divided by cross walls
    septate
  • - vegetative hyphae digest and absorb
    nutrients
  • - reproductive hyphae produce spores for
    reproduction

37
Eukaryotic Cells
Fungal Organization
38
Eukaryotic Cells
Fungal Reproduction - Asexual
-gt Primarily through spores formed on
reproductive hyphae -gt Asexual reproduction
spores are formed through budding or mitosis
conidia or sporangiospores
39
Eukaryotic Cells
Fungal Reproduction - Sexual
-gt Sexual reproduction spores are formed
following fusion of male and female strains
and formation of sexual structure -gt Sexual
spores and spore-forming structures are one basis
for classification.
40
Eukaryotic Cells
Fungal Reproduction sexual
-gt Zygospores diploid spores (2n) are formed
following fusion of male and female
strains -gt Ascospores haploid spores (n),
formed following fusion of male and female
strains in fungal sac -gt ascus zygote (fused)
cells undergo meiosis -gt formation of haploid
spores
41
Eukaryotic Cells
Fungal Reproduction sexual
-gt Ascospores in a fruit body
Ascomycetes -gt Penicillium
42
Eukaryotic Cells
Fungal Reproduction sexual
-gt Basidiospores haploid sexual spores in a
fruit body
Basidiomycetes
Fruit body
43
Eukaryotic Cells
Fungal Classification
  • Subkingdom Amastigomycota terrestrial
  • -gt inhabitants including those of medical
    importance
  • Fungi perfecti (sexual asexual spores)
  • -gt Zygomycota zygospores
    sporangiospores and some conidia
  • -gt Ascomycota ascospores conidia
  • -gt Basidiomycota basidiospores conidia
  • Fungi imperfecti (just asexual cycle know until
    now)
  • -gt Deuteromycota majority are yeasts
    and molds no sexual spores known conidia

44
Eukaryotic Cells
Roles of Fungi
  • -gt Adverse impact
  • - mycoses, allergies, toxin production
  • destruction of crops and food storages
  • -gt Beneficial impact
  • - decomposers of dead plants and animals
  • - sources of antibiotics, alcohol, organic acids,
    vitamins
  • - used in making foods and in genetic studies

45
Eukaryotic Cells
Roles of Fungi
46
Eukaryotic Cells
Kingdom Protista
-gt Algae
-gt Protozoa
Ameba
Diatoms -gt silica cell wall
47
Eukaryotic Cells
Kingdom Protista
Algae
-gt Photosynthetic organisms -gt Contain
chloroplasts with chlorophyll and other
pigments -gt Produce large proportion of
atmospheric O2 -gt Most are free-living in fresh
and marine water plankton. -gt Provide basis of
food web in most aquatic habitats -gt Classified
according to types of pigments and cell wall -gt
Kelps, seaweeds, euglenids, green algae, diatoms,
dinoflagellates, brown algae, and red
seaweeds -gt Dinoflagellates can cause red tides
and give off toxins that cause food poisoning
with neurological symptoms. -gt Used for
cosmetics, food, and medical products
48
Eukaryotic Cells
Kingdom Protista
Protozoa

-gt 65,000 species -gt Vary in shape, lack a cell
wall -gt Most are unicellular colonies are
rare -gt Feed by engulfing other microbes and
organic matter -gt Most have locomotor structures
flagella, cilia. -gt Many can enter into a
resting stage when conditions are unfavorable
for growth and feeding cyst. -gt Most are
harmless, some are animal parasites Pathogen
Protozoa -gt Malaria, Toxoplasmosis
49
Eukaryotic Cells
Kingdom Protista
Cycle of Infection - Protozoa

50
Eukaryotic Cells
Parasitic Helminths (Worms)
-gt 50 species parasitize humans. -gt Acquired
though ingestion of larvae or eggs in food from
soil or water some are carried by insect
vectors -gt Multicellular animals, organs for
reproduction, digestion, movement,
protection Major Groups 1. Flatworms
2. Roundworms

51
Eukaryotic Cells
Parasitic Helminths (Worms)
Life cycle of roundworms
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