Microbiology

Antisepetics are microbe- killing chemicals applied to live tissue


Example... hydrogen peroxide, rubbing alcohol , and iodine

Antibiotics are micro-killing chemical taken internally [pill/ liquid form] 


Example... Penicillin, Ampicillin, Streptomycin, and Chloramphenicol

Applied to inert surfaces

Includes Chlorine bleach and Lysol

The effectiveness of these substances in killing microbes

The clear zone that appear around the disk.

Large the zone of inhibition the better the chemical. 

Astounding diversity and number of microbes, predominantly bacterica and fungi. 

Nitrogen gas that plants can utilize. 

Nitrogen gas that has been converted by soil microbes to other compounds microbiological result

Example ammonia, ammonium ion and nitrate ion

Live inside the roots of legume plants 


Legume plants... clovers, beans, peas, peanuts and soybeans.

Gram-negative bacterica bind to root hair of young legume plant and cause plant to develop root nodule 

Rhizobium fixes nitrogen gas into ammonia, which plant uses for nutrition

Allows both bacteria and fungi to grow

NA 1ml has more microbes b/c 0.1ml less dilute 

Discourages bacteria but encourages fungi to grow

volume of sample / (volume of sample + volume of diluent)

• Prepare the Nutrient Agar and Czapek-Dox Agar plates.
• 1ml of 10^{-4 or} 10^-2 soil dilution then melted NA / CD
• 0.1ml of 10^-4 or 10^-2 soil dilution then melted NA/ CD

number of bacteria colonies and fungi colonies (fuzzy growth)

Fungus-like filamentous soil bacterica

Brown zone around the colony in surrounding agar. 

CFU/g soil sample = (# colonies on plate) * (1/ volume of sample) * (1/dilution)

Production of ammonia from nitrogenous compounds such as casein and peptone

faint yellow

deep yellow to orange 

brown

1/10      10^-1

1/100     10^-2

1/1000    10^-3

Unicellular, eukaryotic microbes in the Kingdom Protista.

Cause diseases in humans 

Detect coliform bacteria in a water sample

follows a positive Presumptive Test, to ensure bacterial contamination due to coliforms. 

• used in Confirmed Test
• selective medium that must indicate Gram- negative bacteria 
• differential medium contain lactose
•  gas bubble produced when coliform are grown (positive Confirmed Test)

final analysis of water sample using EMB and MAC

• selective media that grow Gram-negative bacteria 
• differential media change colors when certain types of bacteria grown on them

colonies have dark centers and green metallic sheen

colonies will be pink/red and pink diffusate visible around the colonies 

easily passed from host to host

diseases passed from host to host

one of the worst bacterial diseases of all time cause by bacterium Yersinia Petstis