MICROBIOLOGYSTUDY 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 free-form 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

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

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 Pasteur

Developed 1st vaccine for Rabies

Used attenuated strain (lost ability cause 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