Sunday, 23 April 2017

A note on Mutazyme and Manganese

Can Mutazyme be powered up?
Adding manganese works poorly, but stronger variants seem to be known.
(see also discussion about Mutazyme in Part I and II)

Tuesday, 11 April 2017

A simple hack for a phylogenetic Noah's ark dilemma

Ever had an endless list of bacterial names that needed a trim?
Ever see a tree where the bacterium chosen is not the famous one, but it's cousin? Or actually a tree where you don't recognise a single name?
The issue of picking bacteria from a list is what I call Noah's ark dilemma. This term is used generally for the biblical problem of the size of the boat required for all the animals in existence (except dinosaurs). Here I mean it picking the most meaningful bacteria from a list. In the past year, I have come to rely on a simple solution: Pubmed popularity.

Sunday, 26 February 2017

Peak height variation

Sequencing a plasmid pool containing a sequence with a randomised codon can reveal the frequencies of the bases are (Acevedo-Rocha et al., 2015 ).
The problem is that sequence traces are not consistent. Some peaks are bigger than others and beyond a certain point the traces get messy. So how does that affect the prediction of the base frequencies?

Friday, 6 January 2017

Top 5 useful facts about the MDS42 strain

MDS42, also known as the Blattner strain, is a strain made in 2006 by deleting 13% of the genome of E. coli K-12 MG1655. Unfortunately, as tools go, it rivals IKEA in cryptic instruction manuals.

Wednesday, 30 November 2016

Saturday, 12 November 2016

The heteroduplicity of error prone PCR plasmids

A mix of wt and
mutant...
In an error prone PCR the ep-aDNA is ligated onto a plasmid backbone and transformed. When assessing the diversity from a naïve plasmid pool, something odd is seen: some bases are mutated but not to saturation. This is often just dismissed or simply overlooked, but I suspect it is actually something interesting...

Thursday, 10 November 2016

DNA gyrase for better yields

Transformation efficiency is a key part of library making... Which gets a bit tricky with large plasmids. A forgotten 90s paper would appear to have a solution, if it were not for a catch.