WENDY CHAO'S LABORATORY PROTOCOLS

INOCULATING BACTERIA using the common bamboo skewer and pretty, sparkly glass beads

GLASS BEADS

Glass beads are very affordable and convenient for spreading bacteria on agar (petri) plates. I recommend the Economical Solid Glass Beads, 3mm from Fisher Scientific (catalog #11-312A, 1 kg or so of beads for around $20).

To sterilize the beads, pour some into a 100 ml glass bottle and autoclave. To use, simply pour a few beads (5-10 or so) onto your agar plates. Squirt 100 ul of bacterial culture onto each plate, cover, and gently shake the plates back and forth to roll the beads around, evenly spreading the culture over the plate. This is a lot easier than having to sterilize one of those silly glass rods every time you spread a plate. You can re-use the beads if you wish - just rinse in water and/or 70% ethanol, and autoclave.

BAMBOO SKEWERS

For picking colonies, forget using those blunt wooden dowels (so clumsy) or sterile pipet tips (what a waste). I like to use those bamboo skewers you use for making shish kabobs - at about $1.50 for a pack of 100 and a variety of lengths, bamboo skewers are the way to go. The sharp tip makes it easy to pick individual colonies from a crowded plate, and the length helps you avoid contaminating cultures. To sterilize, put a bunch of skewers in one of those metal canisters you use for autoclaving pasteur pipets.You can reuse the skewers too - just soak in 70% ethanol after use and re-autoclave. The more you autoclave the skewer, the stronger and harder they get - kind of like seasoning wood to make baseball bats.

You can pick these up at any grocery store. If you want to over-pay for these, go to Williams Sonoma.