In 1976, as an undergraduate student of the Biomedical Sciences course at UNIFESP-EPM (São Paulo), I started my scientific training under the supervision of Dr. Jorge Almeida Guimarães. He was the one who introduced me for the first time to Jackbean Canavalia ensiformis seeds.
Feeling between amazed and horrified, I watched the seizures induced in mice by injection of the aqueous extracts of Jackbean seeds. The aims of my research project at that time were to isolate and characterize the toxic and seizure-inducing principle of these seeds.
In 1978, I graduated as Bachelor in Biomedical Sciences and was awarded the ABIFARMA Prize, first place in the student category, with the work “Seizure-inducing toxin from Canavalia ensiformis”.
In 1980, already married to Jorge, we moved from São Paulo to Niterói, RJ, to work at the Universidade Federal Fluninense (UFF). There I continued studying the seizure-inducing toxin of Canavalia until 1981, when I named it canatoxin and published the first article of my scientific carreer (Carlini & Guimarães, 1981).
In 1982, I was transferred to the Department of Medical Biochemistry, at the Universidade Federal do Rio de Janeiro (UFRJ), where I stayed until July 1997. In my Ph.D. thesis, concluded in 1985 under the supervision of Jorge Guimarães, we described the platelet aggregating activity of canatoxin and the involvement of lipoxygenases pathway in this property of the protein (Carlini et al., 1985).
Soon after I got my Ph.D., I started supervising graduate students, and set the roots of what is today the LAPROTOX. Besides plant toxins, we also studied toxic proteins from snake venoms, always focusing on structure versus function relationships. The 15 years spent at UFRJ were productive and formed a solid base for my scientific career. I cherish every moment of those days for the dear friends and whole-life collaborators of the present time.
I took post-doctoral training, a period of personal and professional growth, from Out/1993 to Nov/1995, at the Department of Biochemistry, University of Arizona, at Tucson, AZ, USA, with a CNPq fellowship. My supervisor was Dr. Michael Wells, one of the founders of the Center of Insect Sciences at U-of-A, a well respected biochemist for his work on the energy metabolism of insects.
At that time two important facts occurred that changed the direction of our research on Canatoxin. The first one happened just before we departed to Tucson: the results on the amino acid sequence of two tryptic peptides of Canatoxin, both of which indicated high homology to jackbean C. ensiformis urease. Initially I thought there was some urease contamination in our Canatoxin preparations, but during my post-doc, after many exhaustive attempts to separate the proteins I finally convinced myself that Canatoxin is an isoform of urease and that these are two different proteins.
The choice of Mike Wells lab for my post-doc training reflected the second fact that changed directions of our studies on Canatoxin: the discovery of its insecticidal properties.
Grace B. S. Barcellos, a very special person, marked profoundly this phase of my life. Grace was in Tucson for a sandwich-Ph.D. at the same time I was there, and her plans were to clone the Canatoxin gene.
Grace had a more plant-oriented view and she was interested in the physiological role of Canatoxin in the plant at a time when I was thinking on its pharmacological effects in mammal models. She divided with me, working on the same bench, all doubts and expectations until the day we concluded that Canatoxin is an isoform of urease. Sharing these moments brought us close together and, closer than a supervisor-student relationship, we became friends.
She passed away, tragically and unexpectedly, at the age of 33, fulminated by a lightening, while hicking mountains in Utah, in August 1995. She left an 8-years old daughter, Lívia. She left incomplete protocols, unanswered questions, emptiness, an unfinished life. I miss you, Grace, wherever you are !
Back to Brasil in November 1995, Jorge and I decided to leave Rio de Janeiro. We wanted more quality of life and safety for our kids, Fernando and Eduardo.
In January 1997, I applied for a full professor position at the Department of Biophysics, Universidade Federal do Rio Grande do Sul (UFRGS). There I started the Laboratory of Toxic Proteins – Laprotox, part of the Center of Biotechnology, and a new team of students and collaborators joined me to study the many aspects of ureases.
In August 2013, now as Senior Research of the Brain Instituto (InsCer) at PUCRS, I started the Laboratory of Neurotoxins – LaNeurotox, where our main focus is to study the neurotoxic properties of ureases and derived peptides.