The Characteristics of Model Organisms

The Characteristics of Model Organisms Lab Manual—2b

Plan for Lab Tues. (1 hr early)—Duffy will start yeast broth Tuesday—Finish Lecture, Parts I, II & III Wednesday—FIRE, Part IV Thursday—repeat Part IV/start write-up

Model Organisms • Relatively easy to grow and maintain in a restricted space • Relatively easy to provide necessary nutrients for growth • Relatively short generation time (birthreproductionbirth) • Relatively well understood growth and development • Closely resemble others organisms or systems

Examples • Animal Kingdom—rats, mice (lots of offspring is a +) • Bacteria—Escherichia coli (E. coli)-prokaryotes • Fungal—Aspergillus (mold)--eukaryotes • Yeast—Saccharomyces cerevisiae

Lab Write-up Purpose Materials Safety Precautions Procedures Data Collection & Analysis (table 2.3—add 8C, only 2 trials to average) Conclusion (aka Data Analysis) REE-results, evidence, explanation PE—possible error PA—practical applications Thinking Like a Biotechnician

Background of Purpose To grow and study an organism in a laboratory, one should know the environmental preferences of the species. Maintaining an organism at less than optimal light intensity, temperature, or oxygen level, from example, may put the organism under stress, possibly affecting its growth or other processes.

Purpose What are the temperature preferences shown by three model organisms (E. coli, Aspergillus niger and baker’s yeast) grown in a biotechnology lab?

Prep. For Lab 2B Month Prior • Check supplies: bleach, petri dishes, LB base, inoculating loops, 3 incubators, yeast, glucose, foil • Order: E. coli, Aspergillus, Potato plates Week Prior • Perez will prepare LB agar & broth • Pour plate (2 per group20) • Set incubators at 30, 37 and 42 C • Scalpels from other room 1 day prior • make bacteria culture

Pre-lab—Plate Pouring • Pour LB agar base plates (Luria-Bertani ) E. Coli plate—use the LB agar with sterile technique, use a 10ml pipette to transfer 10ml into a sterile plate Yeast plate—use the LB* agar, sterile technique, transfer 10ml using a pippet *we are not using Malt extract agar because we do not have it, but LB agar should have enough nutrients to grow yeast

Each group does 1 plate of each organism at their assigned Temperature—wrap in foil for dark • room • room • 30C • 30C • 37C • 37C • 42C • 42C • 8C (instead of the suggested 4C)—please do 2 sets

Part I Tips • Label the bottom • Inoculating loop • Triple Z streaking method • Close lids with tape • Make sure to use plate with LB agar

Part II Tips • Each group gets one plate instead of a tube of potato dextrose agar • We are using a potato dextrose agar plate NOT tube • Cut aspergillus from stock plate—will be in the hood • Put the aspergillus (fungi) on the plate fungi side down to the agar and close the lid

Part III Tips • Label the bottom • Inoculating loop • Triple Z streaking method • Close lids with tape • Make sure to use plate with LB agar

Part IV—Data Collection & Analysis • Make sure to come in at FIRE on Wednesday to do a table like 2.3 (add space for 8C) • We will repeat the table again on Friday in class • This will provide us with more information of what happens over time as well as temperature • The growth is exponential, but when nutrients run out, they go into the death phrase (smelly!), we want to try to catch them at their peak • Use results from all the groups posted on the internet for you data

Tutorials • Media Prep. (13) • LB Agar and Broth (14) • Sterile technique (15) • Pouring Plates (16) • Starting a Broth (18) • Streak Colonies (17)

The Characteristics of Model Organisms