Influenza virus

1
Influenza virus

• Fig. 28.3

2
Tuberculosis

• Fig. 28.10

3
Streptococcus pyogenes

• Fig. 28.9

4
Extreme habitats

• Fig. 28.11

5
Representative green algae

• Fig. 28.12

6
Red alga

• Fig. 28.15

7
Brown alga

• Fig. 28.16

8
Protists contd.

• Other sporozoan diseases
• Toxoplasmosis
• Toxoplasma gondii- oocysts commonly transmitted
  by infected cats
• For most people, it produces only mild flu-like
  symptoms
• In pregnant women it can infect the fetus and
  cause neurological damage
• Cryptosporidium causes mild gastroenteritis in
  most, but can be fatal in people who are
  immunosuppressed
• Passed in feces of infected animals
• Can pass through water filtration processes and
  is unaffected by chlorination

9
Protists contd.

• Molds as protists
• Water molds and slime molds are classified as
  protists
• Both have flagellated cells
• Water molds
• Saprophytic, live off dead matter
• Have a filamentous body with cell walls of
  cellulose
• Produce flagellated spores during asexual
  reproduction
• During sexual reproduction, produce eggs and sperm

10
Protists contd.

• Molds as protists contd.
• Slime molds
• Feed on dead plant material and bacteria
• Plasmodial (acellular) slime molds- exist as a
  plasmodium
• Diploid multinucleate cytoplasmic mass with a
  slimy sheath
• Crawls along forest floor and phagocytizes dead
  organic matter
• Plasmodium produces sporangia which produce
  resistant spores
• Spores germinate to form flagellated cells and
  amoeboid cells
• These fuse and develop into a new plasmodium

11
Plasmodial slime molds

• Fig. 28.22

12
Protists contd.

• Molds as protists contd.
• Cellular slime molds
• Exist as individual amoeboid cells
• Common soil decomposers
• When food is scarce, they aggregate together to
  form a pseudoplasmodium
• This gives rise to sporangia which produces
  spores
• Spores germinate releasing haploid amoeboid cells

13
Sexual reproduction in sac fungi

• Fig. 28.26

14
Dispersal of spores

• Fig. 28.24

15
Fungi contd.

• Imperfect fungi- Phylum Deuteromycota
• Includes many familiar fungi
• Aspergillis- used to make soy sauce from
  fermenting soy beans
• Penicillium- original source of penicillin
• Penicillium roquefortii and camemberti- used in
  making blue cheeses
• Deuteromycetes always reproduce asexually
• Produce conidia on aerial hyphae
• Sexual stage has not been identified and may not
  exist

16
Blue cheese

• Fig. 28.29

17
Fungi contd.

• Medical aspects of fungi
• Fungal diseases of plants
• Many enter through the stomata of the leaves or
  through a wound
• Smuts and rusts- sac fungi that parasitize cereal
  crops
• Fungal diseases of humans
• Mycoses
• Cutaneous- affect only the skin
• Subcutaneous-deeper skin layers
• Systemic-spread throughout the body
• Many fungal diseases are acquired from the
  environment
• Ringworm from soil fungi for example

18
Fungi contd.

• Human fungal diseases
• Tineas
• Skin infections-can occur anywhere on the skin
• Athletes foot- scaling, peeling, and itching
  between toes
• Ringworm- redness and inflammation due to enzymes
  released by the fungus extends outward in a
  ring-shape
• Histoplasmosis
• Caused by Histoplasmosis capsulatum common in
  the Midwest
• Carried in bird droppings
• Mild flu-like symptoms, fungus lives in cells of
  the immune system
• Healed lesions in the lungs calcify
• Candidiasis
• Yeast infections resulting from imbalance of
  normal flora

19
Human diseases caused by fungi

• Fig. 28.32

20
Fungi contd.

• Control of fungi
• Fungi more closely resemble animal cells than
  bacteria
• Makes it harder to develop antibiotics that will
  kill fungi and not the host
• Fungi synthesize steroids differently-fungicides
  are directed at steroid biosynthesis