Monday, November 24, 2014

GUS-pollen: different scopes

A collaborator of mine, Adam Hammond from the University of Chicago, has been working with me looking for the best way to visualize our pistils after a competition. We have been trying out different scopes. I like this one, as it has an extremely wide field, allowing us to get the whole pistil in view. This one is a Zeiss Axiovert 200M inverted widefield with a 4X objective.

Wednesday, November 19, 2014

GUS pollen assay... troubleshooting and sample longevity

Our lab has been generating alot of samples using a genetic construct (Lat52:GUS) that turns pollen blue. Out of curiosity, I took a sample from more than a month ago that had been sitting out at room temperature and checked it out under a standard dissecting microscope. Still looks pretty good. This Columbia accession pistil was pollinated with a large amount of Columbia pollen, spiked with a very small amount of  Columbia pollen containing an integrated Lat52:GUS construct. After 40 minutes, the sample was fixed and stained. Even after more than a month, the blue tubes still look nice and sharp.

Monday, November 17, 2014

Arabidopsis accessions

We've recently completed a genome-wide association mapping experiment using a few hundred Arabidopsis accessions. The amount of variation in these accessions is really stunning (at least to me). Before that we completed quite a bit of traditional genetic mapping using just 3 accessions, Columbia, Landsberg erecta and Vancouver.

One big difference between them, which is kind of a pain, is that the Vancouver accession requires an overwintering to flower. Makes work with Vancouver go a bit slower. When you work with them enough, you can begin to differentiate them on sight. Even when you are just looking at the inflorescence.

Friday, November 7, 2014

Tracking blue pollen in mixed pollinations

We have been optimizing the microscopy of tracking a small number of GUS marked pollen in mixed pollinations with unmarked pollen. The β-glucuronidase gene, or GUS, driven by the LAT52 pollen specific promoter turns pollen blue when stained with X-GAL. This picture is one of many, as we try to get the conditions right for tracking individual pollen tubes.

Tuesday, November 4, 2014

Blue pollen tubes

We have been troubleshooting pollination microscopy in the lab recently. Most of these pictures will never see the light of day in a publication. Here, we have used genetically modified pollen that contain a β-glucuronidase gene (GUS) driven by the LAT52 pollen specific promoter. This turns pollen and pollen tubes blue. After 40 minutes, we fixed and stained.