BIOL368: Genetics and Cell Biology Laboratory

BIOL368 Genetics and Cell Biology Laboratory Project Number: 2 Project title: Sterilization and aseptic technique Name: Alan Sanousian Student ID: 27680104 Lab section: Thursday Afternoon Group: 10 Lab partner: Mathieu Harb Date submitted: 04/10/2018 Introduction: The aim of this project is to understand the use of aseptic techniques in research laboratories and utilize them carefully to avoid contamination (via pathogens from different sources e.g dirty hands, nails, hair etc. encountered while handling bacterial culture). A second aim of this project was also the introduction to different sterilization methods, that are a crucial part of proper laboratory functioning e.g. disinfection and autoclaving. Subsequently, an introduction to different inoculation techniques using both a loop or stick (each one used separately) to isolate pure single colonies from different environments and plating them on different media, followed by their quantification was also done. For quantification, either viable cell counting or optical density measurements of varying dilutions of bacterial cell culture was used. (Concordia Biology department 2018). Aseptic techniques are procedures adopted to ensure proper handling of bacterial cultures in laboratory settings. Flame from a Bunsen Burner is used to heat sterilize glassware (high temperatures kill surface pathogens adhered to glassware) in addition to creating a sterile air corridor that pathogens from contaminating the apparatus used, as they usually fall vertically on the sterile work place. Therefore, all sterile glassware should be held next to the flames when in use.(Concordia Biology department 2018). The first part of the project was the use of aseptic techniques for sterilization of apparatus that would be required for the later part of the experiment. Different sterilization techniques e.g. radiation, autoclaving or filter sterilization can be adopted to sterilize glassware and other apparatus (Concordia Biology department 2018). In the present project, autoclaving of the Erlenmeyer flask and all glassware apparatus was done before preparing different media for the plates. Autoclaving involves application of high temperature and pressure in an enclosed pressure chamber for a definite time period to disinfect objects from all sources of living organisms1. For the succeeding task, streaking was done to isolate uncontaminated colonies of E. coli. This was performed using an inoculation loop, or a stick, which was sterilized and then dipped in the E. coli culture inoculum. It was then streaked on the 25% to 30% of the plate in a zigzag motion. The inoculation loop is reheated and streaked on the adjacent quadrant of the first streak. The second streak begun at the end of the first one. The process was then repeated for the third and fourth quadrants of plate. When streaking using a clean stick, the stick is not heated and discarded after use. A new stick is used to streak for every quadrant of the plate. The next part of the project entailed Next objective was to counting single colonies by plating different samples taken at a dilution of 10-7or 10-6 of E. coli culture) on a selective media (LB). The spread plate technique allows counting of bacterial  colony on a nutrient medium by...