HOSA - Biotechnology: Microbiology & Cell Culture

Model Systems

used by scientists to investigate something new in an organism or biological system they already know a lot about. Model systems are useful for gaining knowledge that can be applied to other systems.

Coccus bacteria

Sphere shaped

Spirilli bacteria

Spiral shaped

bacilli bacteria

oval/rod shaped

sodium chloride

required for growth of most bacteria

aseptic technique

method in cell culture that prevents the introduction of unwanted organisms into an environment

antibiotics

main line of defense against bacterial infections

MRSA

has developed resistance to most antibiotics and si extremely difficult to treat

peptidoglycan

bacteria's cell wall

Gram stain

microbiological stain; gram-positive cell walls in bacteria take up the stain/gram-negative do not

mycoplasma

bacteria that have no cell wall

pili

hair-like projection on outside of bacteria; help w/ cell-cell contact & adhesion

flagella

enable bacteria to move and swim in aquatic environments

aerobic bacteria

prefer high levels of oxygen for max growth rate (called obligate aerobes if NEED oxygen - called facultative aerobes if better but not required for them)

Anaerobic bacteria

prefer to grow in absence of oxygen (called obligate anaerobes if NEED absence for growth - called facultative anaerobes if just better for growth)

psychrophilic bacteria

grow best in cold conditions between -15 and 10 degrees C

mesophilic bacteria

grow best between 15 to 40 degrees C

thermophilic bacteria

grow best between 45 to 80 degrees C (source of Taq DNA polymerase - used in PCR)

hyperthermophilic bacteria

thrive at temperates above 80 degrees C

halophiles

bacteria that live in extremely salty conditions

E. coli

mesophiles that live in human colon; nonpathogenic used in lab research for humans, pathogenic are responsible for food poisoning outbreaks

L. bulgaricus

one of species of bacteria used to make yogurt

lactobacilli bacteria

used in production of cheese, sauerkraut, pickles, kimchi, and animal feed

recombinant protein

protein that is artificially produced in genetically engineered organism - used for therapeutic drugs, agriculture, and food production

Insulin

recombinant protein used to treat diabetes

Bovine somatotropin (BST)

cow growth hormone that stimulates cows to produce more milk

Recombinant bovine somatotropin (rBST)

made by expressing cow somatotropin in bacteria

agar

gelling agent used for growth of bacteria on solid media

solid media

referred to as agar

petri plates

dish used to isolate individual colonies of bacteria, provide large surface area

slants

agar is poured in a tube, allowing it to set at an angle & thus provides large surface area for bacteria growth; Used to culture bacteria for short period of time, not isolation

Bacteria grown on petri plates/slants

stored for 1-2 wks at 4 degrees C

stab cultures

tubes of solid agar with bacteria stabbed into the media, used for storage up to 1 yr

lysogeny broth (LB)

most generic form of solid media - nutrient agar made from peptone & beef extract

Differential media

formulated with chromogenic (colored) substrates to distinguish between diff types of bacteria

Kirby-Bauer disk diffusion test

used to determine effect of various antibiotics on bacteria covering the surface of the agar. the larger zone of inhibition, the greater the antibacterial effect of compound tested

Liquid media (broth)

used to produce large quantities of bacteria suspended in liquid; often formulated w/ same ingredients as solid media but no agar

Liquid cultures

cannot be used for isolation of individual colonies

Terrific Broth

extends growth phase of recombinant E. coli & increases plasmid/protein yield

In solid media,

antibiotics are used to select for resistant bacteria

inoculation loop

platinum or nichrome wire with small loop at end

inoculation needle

straight wire

bunsen burner

used to heat sterilize inoculation loops & mouths of glass bottles, culture tubes, or culture flasks; maintain upward air current to reduce airborne contamination

spreaders

spread bacteria evenly over petri plates

incubators

maintain constant temp; some have shaking platform that allows liquid cultures to be shaken during incubation - oxygenates aerobic culture

fermenters/bioreactors

allow large scale growth of bacteria under controlled conditions

biological safety cabinet (BSC)

must be used whenever doing tests on human disease causing cells; limits chance of aerosol contaminating worker

colony

single bacterium that has multiplied on solid medium into millions of clones of itself; round visible dot on solid medium

serial dilution

diluting a culture several times by the same dilution factor

know all conversions! study from book

example:

optical density (OD)

measures how cloudy a culture is; shows cell concentration

assays

procedures carried out to test or measure activity of a drug or biomolecule in an organism or sample; quantify cells, molecules, antibodies, etc

Gram stain pt. 2

identify unknown bacteria; determine cell wall composition

Bacteria either gram-positive or gram-negative

Gram-positive: thick cell wall; Gram-negative: thin cell wall

Starch hydrolosis test

determines if bacteria produces amylase

Eukaryotes

third domain of life; animals, plants, fungi, yeast, and protists; have nucleus and membrane bound organelles

plasma membrane

regulates what materials enter and leave the cell

phospholipids

create hydrophobic zone that prevent water loss; selective bilayer

fungi kingdom

yeasts, molds, and mushrooms; have cell wall made of chitin

yeast artificial chromosomes (YACs)

extra artificially manufactured chromosomes in yeast to express recombinant eukaryotic genes

Protists

eukaryotes; photosynthetic primary producers Ex. algae

yeast cells

used in baking and brewing

recombinant proteins

made in eukaryotic cells

posttranslational modification

includes glycosylation, a process where carbohydrate molecules are attached to newly synthesized protein

yeast/other fungi cell line (ex. Aspergillus)

cheapest/easiest euk cell to culture for protein production

mammalian cell line

ideal system for protein production; expensive/difficult to culture

antibodies

recombinant proteins produced used as therapeutic drugs

stem cells

can differentiate into new cell types (brain,blood, muscle) depending on molecular signals they are given; replace damaged tissue w brand new tissue

Embryonic stem cells

derived from inner cell mass of developing embryo and are pluripotent (can differentiate into most types of tissue but cannot recreate an entire organism)

induced pluripotent stem cells (iPSC)

allows cells to be removed from patient, and then differentiated into type of cell required to treat patient's disease