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How to shut off background lac promoter expression in LB
2008-04-22 07:24:00 Here’s a tip that you may find useful if you are expressing proteins in E.coli using a lac promoter-based expression system, e.g. pET, in LB medium (L-broth). Lac expression systems are typically induced in the lab using IPTG (isopropyl-beta-D-thiogalacto-- pyranoside), which is a non- hydrolysable analogue of lactose, the natural inducer of the lac operon. Tight control ...
5 Products That Could Make Your Lab Life Easier
2008-04-10 09:35:00 Today I was browsing through the “new technologies” section on the Biocompare website. Apart from the amazing but super-expensive automation equipment that most of us unfortunately have little chance of getting our hands on (at least at the moment), five products caught my eye as being useful for improving techniques widely used by researchers. I ...
Lazy Cell Lysis
2008-03-27 11:35:00 For routine procedures involving cell lysis, it’s good for the lysis to be… routine. Of course there are many good and freely available lysis buffer recipes but for convenience and reproducibility you can’t beat pre-made lysis buffers. Focusing on lysis for protein extraction, here are some of the reagents available for fast and efficient lysis of ...
Ethidium Bromide: The Alternatives
2008-03-03 01:56:00 Last week, in my article about the perils of exposing DNA to UV light during cloning procedures, I mentioned a couple of stains that offer an alternative to ethidium bromide for DNA visualisation. I this article I compare all of the available DNA stains (I know of) that can be used in electrophoresis to clarify the ...
Turn Away from the (UV) Light
2008-02-26 13:45:00 This is a story that could strike fear into your heart if you use UV light to visualize DNA that you later intend to clone. Read on if you dare. A while back I was doing a project where I had to make a mutation library of a plasmid. There are a number of ways to ...
The Best Polymerases of 2008
2008-02-14 12:55:00 Yawn…. The awards season is upon us once again. Overpaid, under-worked and over-ego’d celebrities get together to slap each other’s backs and tell each other how great they are. But little do they know where the real party is in town. The 2008 Thermostable Polymerase Awards (the THEPA’s) are underway and you have a front row seat. ...
Preps in the Zyppy: How I Changed my DNA Miniprep, Gel Extraction and Conce
2008-01-21 10:47:00 After years of loyalty, our relationship was becoming stale - things just weren’t the way they used to be. I was putting in more than I was getting back and complaining about it didn’t seem to help. I just got the same old answer thrown back at me… “it’s not our problem, it’s yours”. Then things ...
An Easy Lysis / Homogenization Method for Any Sample
2007-12-05 13:41:00 At the moment, one of my colleagues is preparing hundreds of cell-free extracts from microbes isolated from the environment to screen for interesting enzyme activities. Lysis of some microbes is easy, but for others its much more difficult - I think due to differences in the make-up of their cell wall (any microbiologists out there care ...
Electroporation on a (96 well) Plate
2007-11-29 13:30:00 I just came across a neat device now being offered by BioRad that may interest those of you who do a lot of electroporation of difficult-to-transfect mammalian cells, where tedious optimization of the electroporation protocol itself is required.
5 Ways to Clean Up A DNA Sample
2007-10-25 16:20:00 One of the most common tasks in molecular biology is cleaning up DNA from aqueous solutions to remove buffer salts, enzymes or other substances that could affect downstream applications. Examples include cleaning up PCR reactions, digests or other enzymatic treatments and cleaning up genomic or plasmid DNA contaminated with cellular proteins/debris. There are several ways ...
An Attractive Genomic DNA Isolation Kit
2007-10-03 16:22:00 I was becoming a bit bored with the tedium of column-based kits, so when I had to isolate genomic DNA from a range of micro-organisms for a recent project I decided to try something new. Invitrogen’s ChargeSwitch genomic DNA isolation kit, which uses magnetic beads to separate the gDNA from the cell debris, seemed ...
Ethidium Bromide: A Reality Check
2007-09-26 13:15:00 The hysteria among molecular biologists about our old friend ethidium bromide has long been an irritation to me. Researchers are rightly wary of this potential carcinogen. More recently this wariness has been whipped up into a witch hunt by companies touting “safer” alternatives and disposal methods. While I don’t for a minute think that ...
Protein Expression with a Cherry on Top
2007-09-24 13:32:00 If you do a lot of heterologous protein expression, take a look at Eurogentec’s CherryExpress Kit. Based on the T7 expression system, the CherryExpress vector has a sequence encoding a small red polypeptide (the heme binding part of cytochrome) fused to the promoter. When your favorite gene is cloned in, the resulting fusion protein is ...
Custom Gene Synthesis: A PCR alternative.
2007-09-05 16:02:00 The past few years have seen the emergence of custom gene synthesis as a useful but expensive service available for molecular biologists. Recently, the number of companies offering custom gene synthesis has exploded, pushing the cost of the service down to much more affordable levels.
Capturing viral diversity for in-vitro test reagents and hiv vaccine immuno
2007-04-07 17:04:00 Page: 183DOI: 10.1097/COH.0b013e3280f3bfe2Aut-hors: Brander, Christian a; Self, Steve b; Korber, Bette c (Source: Current Opinion in HIV & AIDS) More: continued here |
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