MICROBIOLOGY
STUDY OF BACTERIA & VIRUSES
WHAT ARE MICROBES?
 Microscopic organisms
that include bacteria,
fungi, algae, protozoa &
viruses
 Less than 5% are
classified as pathogenic
(disease causing)
WHAT DO M/O’S NEED?
 Water
 Food/nutrients
 Oxygen

Aerobes, anaerobes, facultative
anaerobes
 Temperature



Psychrotrophic (32-45 F)
Mesophilic (60-110 F)
Thermophilic (110-150 F)
 pH


7 optimal
Reproduce 4.5 - 10
REPRODUCTION
 Bacteria

Binary Fission
1 bacteria clone itself
 Produce 2 identical cells


Conjugation
Two bacteria share genetic
information
 Produce 2 new cells


Transformation

Bacteria takes genes from
environment
REPRODUCTION
 Molds

Fragmentation


Pieces break off & create
new individual
Budding
Copy (similar b. fission)
 New copy break off of
original


Spores

Reproductive cells
released  either freeform or join w/ another
BACTERIA
 Prokaryotic cells


No nucleus
Contain genetic material
 plasmid



Single round chromosome
Ribosomes –make
proteins
Pilli
protein hair-like
structures
 Help cells attach


Flagella

movement
BACTERIAL STRUCTURES
 Cell Wall
 Rigid structure either carbs or
proteins
 Prevents osmotic pressure
(cytolysis)
 Capsule
 Sticky gelatin surrounds c.wall
 Prevents wbc from attaching
 Outer Membrane (some forms)
 Toxic lipid bilayer
 Endospore (some forms)
 Hard outer covering
 Prevents drying out
 Allows go dormant
MOLD
 Eukaryotic Cells
 Cross between plant &
animal cell



Cell walls
No Chloroplasts
Consumers  saprophyte
(absorb nutrients from
dead, decaying organisms)
MOLD
 Multi-cellular organisms
composed of branches
called “hypae”


Vegetative hypae 
attached to host
Aerial hypae  absorb O2
from air
M/O IN ENVIRONMENT LAB
 What area of EPHS will
support the most amount
of microbial growth?
 20 Possible locations:
1.
2. 3. 4. 5. 6. 7. 8. 9. -
10. 11. 12. 13. 14. 15. 16. 17. -
18. 19. 20. 21. - Control
THEORIES ON DISEASE
 Prior to physical evidence of m/o’s
 Common beliefs  witchcraft, sins against God
 Lucretius (Roman philosopher)
Published theories form of poem
 Renounced idea of gods/spirits


Fracastoro

Theory of chemical “spores” travel great distances
 Leeuwenhoek
 Credited w/ discovering bacteria
 Looking a plaque family member’s teeth
GERM THEORY OF DISEASE
 Bassi


Discovered silkworm
disease caused by a fungus
Killing caterpillars &
destroyed silk industry
 Berkeley

Proved Great Potato
Blight caused by a fungus
GERM THEORY OF DISEASE
 Lister


Developed system
antiseptic surgery
Combination heat &
phenol alcohol
 Koch


Developed criteria proving
relationship btw m/o’s &
disease
Studied anthrax
 Koch’s postulates




M/o found all cases disease
Maintained pure culture
Produce original infection, after
generations in culture
Isolated from inoculated host &
recultured
GERM THEORY OF DISEASE
 Gram


Developed system of staining
procedures
Divides bacteria 2 grps
Gram +  turn violet
 Cell walls simple carbs
 Less pathogenic
 Gram - turn red
 Cell walls protein & extra
lipid outer membrane
 Resistant antibiotics
 Pathogens

 Pasteur


Developed 1st vaccine for
Rabies
Used attenuated strain
(lost ability cause disease)
BACTERIAL SHAPES
 Cocci (coccus)

Round cells
 Bacilli (bacillus)

Rod shaped
 Spirella (spirellum)

Thick, rigid spiral
 Spirochete

Thin, flexible spiral
 Vibrio

Curved, comma shaped
BACTERIAL ARRANGEMENTS
 Diplo


Arranged in pairs
Diplococci, diplobacilli
 Strepto


Arranged chains
Streptobacilli
 Staphlo


Arranged in clusters
staphlococcus