Friday, July 10, 2009
I made a tree for a Biology class this past semester from Dr. Andrea Porras-Alfaro http://sites.google.com/site/andreaporrasalfaro/and found out that a chloroplast gene AJ536457_1 Odentella sinensis (a cyanobacterium) was cloned and sequenced from a water filter that was collected from the mound spring at Tierra Amarilla in 2007.
I talked with a fellow graduate student this morning and we had a good conversation about diatoms! Diatoms are my second hobby, with microbes being my first. He wants to do some interdisciplinary work with my advisers and myself to investigate the role that diatoms have in the production of calcite. He looks at the isotopic configuration of the silica shell and determines where the oxygen in their bodies comes from. I am interested in the symbiotic relationship between microbes and diatoms and the possibility of HGT between the two. Our conversation prompted me to look up my old research paper for this class I took. I spent an hour or so today looking at the NCBI citations and turns out I forgot what it meant if this gene I sequenced was a chloroplast gene from Odentella sinensis. Odentalla sinensis is a chromista. So, a chromista is: http://www.ucmp.berkeley.edu/chromista/chromista.html. Turns out I needed a refresher on plastids as well. A plastid is: http://en.wikipedia.org/wiki/Plastid... if you are into wiki definitions. So, according to the NCBI results, the O. sinensis diatom species is living at the water's surface and we extracted, cloned, and sequenced its chloroplast gene that previous research has concluded is evidence for some sort of symbiont relationship -or- HGT.
There is quite a bit of work that has already been done on the horizontal gene transfer between certain mitochondria and plastids. One such study shows HGT between an algae and a diatom species (An exceptional horizontal gene transfer in plastids: gene replacement by a distant bacterial paralog and evidence that haptophyte and crypotphyte plastids are similar: BMC Biology: 2006: Rice and Palmer) Does this mean that there could be a gene in a diatom (the Odentalla sinesis) at Tierra Amarilla which was acquired through HGT from a photosynthetic bacterium?
Another interesting note: we cultured, yes, CULTURED diatoms and cocci bacteria on the same plate last year when we sampled at Soda Dam (above picture). How the heck does this happen? Well, it is Friday, so first thing Monday (after I PCR and ligate my own water filters for their long trip to WashU) I am going to pay a visit to Becky Bixby, UNM's own diatom specialist . As if I have time to pursue this, but I've been advised to keep at least one scientific hobby for my own sanity.