On Wednesday, November 18, Kim Chhor, Michael Rhee (Dr. Hutter's lab, Pediatrics), Jennifer Eugster (Drs. Grimes and Smith's lab, Bio-chemistry), Miguel Loustaunau (Dr. Collins' lab , Pediatrics) and I set out to introduce a new UBRP faculty sponsor to the program's many advantages. Dr. Rich Jorgenson, Associate Professor in Plant Sciences, was pleasantly surprised when he was invited to go out, have a free lunch and talk science for an hour or so. So off we went, heading towards Nam Son, a family run restaurant serving Chinese and Vietnamese food at very affordable prices at Park and Sixth. Nam Son, itself, has had a long history. Originally known as the Eggroll House, it changed owners in the summer of 1997 and has since gained in popularity. Their specialty is Pho soup, a beef broth with beef and rice noodles, to which one can add bean sprouts, basil leaves, lemon and several sauces, including their popular fish sauce.

As it was one of those incredibly appealing Tucson November days, we opted to sit outdoors. Dr. Jorgenson shared his research with us. Plant scientists often work on trying to find ways to over-express endogenous genes in plants in order to produce flowers with enhanced aesthetic characteristics or food products with greater nutritional value, for example. To do this, one designs a transgene using molecular recombinant techniques, and then inserts the transgene, under control of a promoter, into the plan's genome. This can be done in many ways, including using a bacterial host, that itself has the capability of inserting its own DNA into the plant. By removing the deleterious genes in this bacterium and then replacing them with the genes of interest, one can produce a plant with modifications in its genome.

Upon successful plant transformation with the high expressing transgene, the researcher sometimes finds that instead of overproducing the gene of interest, the transgene actually silences itself plus the other homologous genes already in the genome. This is known as "sense co-suppression." In order to study this type of gene silencing, one has to have a mechanism for identifying if the expression of a gene has changed in any way. Dr. Jorgenson uses the Chalcone synthase gene, whose protein product is necessary for the first commitment step in flavanoid biosynthesis, including anthocyanin. The localization of purple anthocyanin pigments in petunias causes the wide range of color patterns in these flowers. Effects on the pathway producing these pigments can be seen as changes in the color patterns of the flowers. This system allows for recognition of changes in gene expression and thus can be used in studying effects of transgene number, promoter strength, or other possible factors on the gene silencing mechanism.

It this kind of research sounds interesting to you, Dr. Jorgenson would enjoy talking with you and explaining what is happening in his lab. A very interesting research subject, and of course, a very appealing research oppor-tunity to any plant lover!

Susanne Rafelski, UBRPer in Dr. Galbraith's lab in Plant Sciences.