STUDY OF BACTERIA & VIRUSES MICROBIOLOGY

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 ( F)  Thermophilic ( F) pH  7 optimal  Reproduce

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 O 2 from air

M/O IN ENVIRONMENT LAB What area of EPHS will support the most amount of microbial growth? 20 Possible locations: 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 Pasteur  Developed 1 st 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

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