A nano-key unlocks the secrets of DNA. Scientists at the ENG Center for Advanced Biotechnology (CAB) have designed a tiny biomolecular device capable of opening an extended region within a designated site of the DNA double-helix. The device facilitates their ability to manipulate and read the sequence of genetic material and detect changes wrought by such factors as mutations, viruses, or bacteria.
The new DNA nanostructure, known as a PD-loop, is made up of a double-stranded DNA segment, a pair of PNA (peptide nucleic acid) molecules, and a specific probe designed to detect and quantify particular patterns indicating the presence of foreign genetic material, such as that of the HIV virus. The PD-loop was bioengineered by Vadim Demidov, CAB senior research associate, Biomedical Engineering Professor Maxim Frank-Kamenetskii, and colleagues.
PNA is a synthetic mimic of DNA developed in 1991 by a group of Danish researchers with whom the BU team collaborates. PNA has the ability to invade the DNA double helix, displacing one of the strands and creating a space so that the probe can bind to the exposed DNA in search of the targeted sequences.
"Because the PD-loop works on double-stranded DNA, as it occurs in living tissue," says Demidov, "this nanotool overcomes many problems inherent in existing techniques that require that the DNA strands be separated before a probe can be effective."
The PD-loop has potential applications for advanced research in molecular biotechnology and in the development of new, more effective medical diagnostics. It also has potential to spur the development of new pharmaceuticals based on the repression or activation of targeted genetic sequences.
The most recent member of the PD-loop family, an artificial primosome, will be described in an upcoming spring issue of ChemBioChem. For further information, see: http://www.pnas.org/cgi/reprint/95/10/5516.pdf.
Musical Myths. Traditional music can be understood only in the context of the culture that produces it, according to Sally Sommers-Smith, CGS associate professor of science and mathematics. Her paper, "The Dangerous Energies of Such a National Inheritance: Myth and the Traditional Music of Ireland," to be published this spring by the American Conference on Irish Studies, examines Irish traditional music in the context of assumptions about Irish life and culture.
In general, traditional music is assumed to grow out of a strong rural working culture, be transmitted aurally, and arise, "almost as a smoke, from the collective consciousness of a people," rather than being the product of an individual composer. In contrast, says Sommers-Smith, Irish traditional songs and dances are generally attributed to individual artists, who are likely to be named in the titles of the tunes or remembered by the performer.
Although the music is easily identifiable as Irish, it incorporates other popular European musical forms. Nonetheless, Irish music "carried with it a suspicion of the exotic and dangerous." During the late 18th and 19th centuries, collectors and popularizers such as Edward Bunting and Thomas Moore adapted the music from the traditional harp and pipes to the pianoforte, laboring to preserve the "genius of Irish melody . . . [while eliminating] the primitive and even dangerous associations of the untranslated music."
Sommers-Smith describes it as "a powerful music declawed." Such recent theater hits as Riverdance and Lord of the Dance attest that traditional Irish music is still being adapted to appeal to the CD-buying and concert-going public. However, she concludes, "It is also clear that if traditional music can survive the transformations and misunderstanding of the past, it can surely survive the commercial success of the present."
Briefs" is written by Joan Schwartz in the Office of the Provost. To read
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