Chapter 3 Micro

method of culturing microorganisms (5 I’s)

inoculation, incubation, isolation, inspection, identification

inoculation is

introducing sample to media

incubation

stored under appropriate conditions to result growth in culture

isolation

separates a specific type

inspection

looking at it growth, shape, color

identification

determining what it is

what is the physical state of media

liquid (broth), semisolid (soft), solid (agar)

if its semisolid what does it help determine

if it can swim, it will be everywhere, if not, it will be just in one area (motility)

chemical composition of media

chemically defined (synthetic) - know exactly what is in it

complex; not chemically defined (beef extract, milk, blood, etc) - roughly know but not exact

functional type of media

general purpose (like TSA or NA) - anything should grow

enriched (growth factor, blood, etc) - nutrients been added, anything can grow

selective - chemicals are added to prevent growth, so some grow and some don’t

differential - anything grows but have different results

selective and differential - some grow and some don’t + different results

anaerobic growth - doesn’t use oxygen, some don’t even grow

basic media

agar plate, agar deep tube (semisolid so you need a needle), broth, agar slant

selective medias

MacConkey Agar: G(-) enterics (intestine bacteria)

Mannitol Salt Agar: staphylococci and streptococci

Azide agar: G(+)

Eosin Methylene Blue Agar: G(-) enterics

Sabouraud’s Agar: fungi (lower pH)

differences for differential media

colony color/size, media color change, formation of gas bubbles, formation of precipitates

differential media

blood agar: hemolysis

mannitol salt agar: mannitol fermentation

MacConkey agar: lactose fermentation

urea broth: urea hydrolysis

eosin methylene blue agar: lactose fermentation

carbohydrate broth: fermentation - acid and gas

selective and differential media

mannitol salt agar: staphylococci and streptococci, mannitol fermentation

MacConkey agar: G(-) enterics, lactose fermentation

Eosin methylene blue agar: G(-) enterics, lactose fermentation (shiny)

isolation techniques

streak plate technique (loop), pour plate technique (inside the agar), spread plate (hockey stick to spread)

kilometer (km)

10³, 1,000 , thousand

meter (m)

1

centimeter (cm)

10^-2, 0.01, hundredth

millimeter (mm)

10^-3, 0.001, thousandth

micrometer (um)

10 ^-6, 0.000001. millionth

nanometer (nm)

10^-9, 0.000000001, billionth

what can you see with your eyes

eukaryotic cells

what can you see with a light microscope

bacteria, organelles, eukaryotic cells

what can you see with electron microscope

small molecules, lipids, proteins, virus, bacteria, organelles

scanning

red, objective lens 4x, ocular lens 10x, total magnification 40x

low power

yellow, objective 10x, ocular 10x, total magnification 100x

high power

blue, objective 40x, ocular 10x, total magnification 400x

oil immersion

white, objective 100x, ocular 10x, total magnification 1000x

objective lens form

real image

ocular lens form

virtual image

wet mount is

fresh, living in water, broth, saline, used to observe locomotion

fixed stained smears

positive stain: stain bacterial cell (opposites attract)

negative stain: stain background

most bacterial cell surface is

negatively charged and acidic

simple stain is for and which dyes

all is one dye/color and quick observation, crystal violet, and methylene blue

differential stains

gram stain, acidic fast stain (mycobacterium), endospore stain

special stains

capsule stain and flagellar stain

for gram stain which color is what

purple: g(+)

red: g(-)

what color means what in acid fast stain

red: acid fast (mycolic acid)

blue: non-acid fast

if you use a g(-) stain

the background gets stained

if you use a g(+) stain

the cell gets stained

what stains are g(-)

nigrosin (blue-black) and india ink (black)

differential staining

uses two colored dyes to contrast between cell types

gram staining

if g(+) will turn purple, if g(-) it will be pink or red

endospores are from

genus bacillus and clostridium, usually aren’t stained unless specifically done

capsule stain

rods and the capsule isn’t stained

g(-) has

thin wall as so pink

g(+) has

thick walls so purple

if it is acid fast, it means

it has thick, waxy walls that is usually mycobacterium tuberculosis

what are endospores

they are dormant and difficult to kill, they are produced after nutrients are all gone so they can grow again somewhere else

what usually can swim

rods can with the use of flagella (protein fibers)

fermentation is

anaerobic (no need of oxygen), creates acid and gas

a change in color shows

a pH change, like more acidic