The MBL researcher who focuses on the chromosomes of an African parasite, will be at Brown in the spring.

by Allison Whitney '05

Stephen Hajduk, a researcher at the Marine Biological Laboratory (MBL) in Woods Hole, has found a kindred spirit in the chromosomes of African Trypanosomes. Trypanosomes are single-celled parasites which use a mentoring process to fix typo-like errors in messenger molecules. Hajduk, who will be a guest lecturer in two Brown courses next semester, directs the Molecular Pathogenesis and Molecular Infectious Disease Program and is an active mentor to his students, firmly engaged in their development as researchers.

For Hajduk, working at the Marine Biological Laboratory was a dream he had as an undergraduate at the University of Georgia. However, at that time his interest was in marine biology, not African Trypanosomes. As a student he worked as a technician in marine biology laboratories. When it came time for him to do a senior honors research project, regulations prevented him from completing it on the same research that he was paid to do as a technician. Instead, the young Hajduk worked with another researcher in the same lab who studied African Trypanosomes. He has been hooked on them ever since.

Trypanosomes' distinctive biological characteristics have important real-world applications. Certain species of Trypanosomes cause human sleeping sickness, which is estimated to have killed 60,000 people throughout equatorial Africa in 2002 alone. The Hajduk Lab at Woods Hole studies the natural immunity of humans to a different Trypanosome species which causes Nagana, a bovine disease. By studying this natural or "innate" immunity, drugs can be developed to fight the Trypanosomes that cause sleeping sickness. This is accomplished by understanding the molecular processes that differentiate Trypanosome cells from human cells.

Hajduk specializes in the unique mentoring process which takes place in Trypanosome mitochondria. Mitochondria are compartments in all cells where the energy from sugars is harvested. Trypanosomes have special chromosomes in their mitochondria that instruct the cell how to make the proteins needed for the harvesting process. This information is relayed by messenger RNA (mRNA) that help translate the DNA into proteins that are the functional product of the genes. For example, the gene for hemoglobin will encode the oxygen-carrying protein of red blood cells.

However, unlike mRNA found in most other life forms, the mRNA of Trypanosome mitochondria contain many deletions in the message they carry. The faulty (but complete) Trypanosome mRNA pair with other small fragments of mRNA bearing the corrected sequence for a small portion of the message. The small fragment instructs the larger one how to correct the typos, thereby allowing a functional protein to be made. This unique system evolved in the parasiteÕs mitochondria and is not found at all in human cells. Therefore, this process of RNA editing could be targeted by drugs in order to cure sleeping sickness.

Looking back over his 20 years of research on these "gorgeous cells," Hajduk recalls best the graduate students who have worked in his lab, explaining that they create a great atmosphere and energy in the lab. Perhaps most important is the relationship he develops with them over the years they work together, which reminds Hajduk of the mentors he had as student, and with whom he is still in contact.

His emphasis on the importance of mentoring relationships in the scientific community is one reason he is very excited by the new partnership between Brown and the MBL. As a research laboratory and not a university, the MBL does not have long-term students of its own. Thus, Hajduk is eager to again have the opportunity to teach and work with students in his lab, which he has missed since he joined the MBL early this year. In addition to lecturing at Brown next semester, he plans to offer a short seminar about innate immunity at the MBL.

Hajduk can be reached at The Josephine Bay Paul Center, The Marine Biological Laboratory, 7 MBL St., Woods Hole, MA 02543 or by e-mail.