Micro Pre-Lab 9

pyruvate (alcohol fermentation rxn)→

acetaldehyde +CO2→ethanol

alcohol aka→

ethanol (ethyl alcohol)

what happens to NADH in fermentation?

oxidized to NAD+

gas produced in alcohol fermentation→

CO2

microbe used to make wine

yeast (Saccharomyces cerevisiae)

2 coliforms

• E. coli

• E. aerogenes

EMB agar selection

inhibits gram + bacteria by using eosin and methylene blue dyes

non-coliforms on EMB

colorless/pale colonies

E. coli on EMB agar

small dark colonies with green metallic sheen

E. aerogenes on EMB agar

large colonies with dark center and light border (fish-eye)

bacteriophage

virus that infects bacteria

what phages inject

DNA/genetic material

purpose of plaque assay

to determine # of phages (PFU/mL)

types of phages

lytic and lysogenic

type of phage used in titer

lytic

top agar

contains soft agar, E. coli, and the phage

plaque

clear zone where bacteria were lysed

each plaque represents

one phage particle (PFU= plaques x dilution factor)

countable plaque range

30-300

how fleming discovered lysozyme

observed bacteria killed by nasal mucus/tears/saliva

lysozyme

breaks B-1,4 bonds btwn NAM and NAG in peptidoglycan in cell walls

S. aureus found in

skin and nasal passages

% of people with S. aureus in nose

20-30%

problem with treating S. aureus

antibiotic resistance (MRSA)

how S. aureus spreads

skin/skin or contaminated surfaces (direct contact)