What’s The Problem With Ampicillin Selection?

Ever wonder what those small colonies, like satellites, surrounding a larger E. coli colony on your LB with ampicillin plates were? Or why, when you picked that colony, it never had the plasmid you just transformed? Well, it’s because those satellite colonies are “protected” from the ampicillin by the big colony. Read on for more… Ampicillin…

express proteins

How to Express Proteins Across Kingdoms: Prokaryotes vs Eukaryotes

In the sci-fi novel Terminal World by Alistair Reynolds, a planet consists of zones with defined characteristics of matter interactions on a subatomic level. These conditions permit different levels of technology sophistication in various zones. For example, in the “Steamville zone” nothing more complicated than steam engines works – electronic schemes fuse irreversibly. Something like…

8 Basic Points to Remember Before Expressing Proteins in Bacterial Systems

8 Basic Points to Remember Before Expressing Proteins in Bacterial Systems

As a protein biochemist and a Ph.D. student, I was given the task to express a eukaryotic protein in a bacterial system. And to say that I was having a hard time would be an understatement. It took me many PCRs, cloning and transformations to get to the right construct that would eventually express the desired…

Am I Damaging My  E. coli by Spinning at High Speeds?

Am I Damaging My E. coli by Spinning at High Speeds?

Dear Aunt Yersinia, A very annoying postdoc in our group keeps telling me off for spinning E.coli at 13K in a tabletop centrifuge. The postdoc claims that high speed damages cytoskeleton and this will reduce my transformation frequency. But I don’t believe her as the cells are cushioned by water during centrifugation. Can you tell…