Nicholas C. Carpita

As a doctoral student, Dr. Mauricio Antunes, developed a novel chemically inducible promoter system from Aspergillus for use in crop plants. Several examples of chemical control of gene expression in plants exist today, but none meets all of the requirements necessary to use in an agricultural setting. These include synthetic promoter systems that can be induced by tetracycline, steroid compounds, copper ions, and ethanol.  Mauricio is currently a post-doctoral associate in the lab of Dr. June Medford at Colorado State University, where he works on a project involving the engineering of receptors to generate sentinel plants against bioterrorist agents.

In collaboration with Wolf-Dieter Reiter and Gary Vanzin, University of Connecticut, Dr. Mike Madson provided the chemistry needed to confirm the identify the genes responsible for the alteration of xyloglucan structure of mur2 and mur3.  MUR2 was identified as a xyloglucan-specific fucosyl transferase, whereas MUR3 was shown to encode a xyloglucan-specific galactosyl transferase whose activity is requisite for subsequent fucosylation by the MUR2 enzyme.  Mike is currently a staff scientist at the Dionex Corporation, Sunnyvale, CA.

Dr. María (Txus) Peña studied the determinants of cell-cell adhesion in apple, discovering that a loss of arabinose pre-staged a loss of branching of RG I chains.  The loss of branching was strongly correlated with a loss in textural integrity.  In another study, María showed that galactosylation of xyloglucans was essential for maintenance of tensile strength in the Arabidopsis etiolated hypocotyls, and she provided the first evidence for a role of XET activity in the maintenance of wall strength.  María is currently in the lab of Dr. Will York at the Complex Carbohydrate Research Center using NMR to characterize taxanomic-significant variation in xyloglucan oligomeric profiles.

As a doctoral student, Dr. Iris Perez-Almeida characterized the temporal and spatial expression of the Family 35 b-galactosidase genes of Arabidopsis, and began to characterize their specific functions.  Iris is currently a researcher at the National Center of Agricultural and Husbandry Research (CENIAP) at the National Institute for Agricultural Research (INIA).  Her group is responsible for application of biotechnology to assist rice genetic breeding in Venezuela to increase resistance to biotic stress and quality traits.

As an undergraduate Honor’s student, Breeanna Urbanowicz established the topology of the maize mixed-linkage (1→3),(1→4)-b-D-glucan synthase at the plasma membrane.  She found that the catalytic domains responsible for synthesis of cellotriose and higher odd-numbered units of the glucan were facing the cytoplasm.  Her work led to the discovery of an extrinsic protein factor involved in the glycosyl transfer.  Breeanna is currently a doctoral student at Cornell University in the lab of Dr. Joss Rose, where she is characterizing a novel class of polysaccharide hydrolases that have cellulose-binding motifs.

As a doctoral student, Dr. Claudia Vergara characterized the maize, rice and Arabidopsis CesA gene family.  She established that the hypervariable region found in between the U-motifs wasn’t hypervariable but represented a class-specific structure that she hypothesized was important for protein-protein interactions needed for catalysis.  After a post-doctoral experience with Dr. Tony Bacic at the University of Melbourne, Australia, Claudia has returned to the US to work on glucan synthases of rice with Dr. Jonathan Walton at the Plant Research Lab, Michigan State University.