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- Worms in space |
Researchers in the laboratory of Dr. Graham Hatfull (left) have been engaged in the isolation and characterization of mycobacteriophages - viruses that infect microbes such as Mycobacterium tuberculosis and M. smegmatis. While several such phages have been studies in some detail, it is thought that the number and diversity of these viruses is huge. As the Hatfull has recently demonstrated, the study of the mycobacteriophages has many advantages: they have revealed new insights into gene regulation and site-specific recombination as well as facilitated the development of novel tools for the diagnosis, prevention and cure of mycobacterial diseases.
Last summer, Bill Brucker (at right) - an undergraduate at Brown University - studied in the Hatfull lab as a fellow in the Howard Hughes Medical Institute Program. Bill's project was to isolate and characterize new mycobacteriophages. He did so by searching among samples taken from numerous environmental locations. While Bill successfully isolated several new phages, among the most interesting is one that he named Corndog (at left, image colorized by Roger Hendrix). This name derives from the viral morphology as seen by electron microscopy, which reveals an elongated head attached to a long flexible tail. This morphology is entirely new among mycobacteriophages, all others of which have isometric heads; in fact, this head shape is very unusual among all previously characterized phages.
The inability to make any sensible prediction about the genome of Corndog reflects our dearth of understanding about phage genomics and evolution. However, the prospect of isolating many new mycobacteriophages and dissecting their genomes offers an exciting opportunity to address these important questions. Moreover, as the worldwide problem of drug-resistant tuberculosis grows, there is hope that the study of Corndog and other new mycobacteriophages will fuel the development of new strategies for controlling mycobacterial diseases. |
We are in the process of determining the genomic sequence of Corndog and completion is expected shortly (watch this space!). Our previous genomic studies, however, make is difficult to predict what the genome will look like. On one hand, the altered shape could reflect a more distant overall relationship to other mycobacteriophages. On the other hand, previous studies of viral assembly (such as those conducted in |