July 23, 2016 at 05:35AM

Today I Learned: 1) ...what a persian cucumber tastes like. It's a lot like any other cucumber, except with more of that slightly bitter, refreshing cucumber taste. As a bonus, I learned that a bit of lemon juice, salt, and pepper do wonders for a cucumber salad. 2) One of the major classes of antibiotics is the aminoglycosides, which includes kanamycin, neomycin, and streptamycin, among many others (incidentally, antibiotics with "mycin" in their name are derived from Streptomyces bacteria). Aminoglycosides work by binding in the bacterial ribosome, which messes up the ribosome and stops it from making functional proteins. I always assumed that aminoglycosides just stopped protein production, but today I learned that aminoglycosided ribosomes actually continue to make protein... but they don't incorporate amino acids accurately, so the proteins they make usually have the wrong sequence and often are prematurely terminated. As a bonus, today I also learned that aminoglycosides are something of a last-resort antibiotic, or a general-purpose one if the infection can't be diagnosed. They're specific to bacterial ribosomes... but not *completely* specific to bacterial ribosomes, so they can cause some nasty side effects in humans. 3) Transposase libraries are usually made with viral transposons. I'm not sure why viral transposases... but then, I'm not intimately familiar with the protocol for building a transposase library. The basic idea of a transposase library, by the way, is to generate tons and tons of variants of (usually) a bacteria with genes randomly knocked out. Transposases are small genetic elements that can randomly insert themselves into the genome of a host, and can be found in pretty much all clades (though they're much more common in Eukaryotes, especially Eukaryotes with big genomes). To make a transposase library, you introduce a transposase to a population of cells and induce the transposases to insert for a short time. Each cell will get a transposase in a different location. If the transposase inserts inside a gene, it will usually shut down the function of that gene, so the library of transposase-infected cells serves as a knockout library that you can screen in the usual ways.