Scientists now have a better understanding of how short DNA strands decompose in microseconds. A European team found new fragmentation pathways that occur universally when DNA strands are exposed to metal ions from a family of alkaline and alkaline earth elements. These ions tend to replace protons in the DNA backbone and at the same time induce a reactive conformation leading more readily to fragmentation. These findings by Andreas Piekarczyk, from the University of Iceland, and colleagues have been published in a study in EPJ D. They could contribute to optimising cancerous tumour therapy through a greater understanding of how radiation and its by-products, reactive intermediate particles, interact with complex DNA structures. In cancer radiation therapy, it is not the radiation itself that directly damages the DNA strands, or oligonucleotides. But rather, it is the secondary reactive particles, leading to the creation of charged intermediates. Here, the authors have studied one of these charged intermediates in the form of so-called protonated metastable DNA hexamers. To do so, the authors created selected oligonucleotide-metal-ion complexes that they selected to have between zero and six metal ions. They then followed these complexes' fragmentation reactions using a technique called time-of-flight mass spectrometry. By comparing … Continue reading →

A Texas judge has ruled that DNA evidence probably would not have cleared convicted killer Henry Skinner of the three murders that sent him to death row. Skinner, 52, was condemned for the 1993 New Year's Eve murders of his live-in girlfriend Twila Busby and her two adult sons, Elwin Caler and Randy Busby. Skinner, a verbally combative paralegal whose case gained international attention in anti-death penalty circles, consistently argued he had been incapacitated by alcohol and codeine when the killings occurred. Skinner twice received last-minute stays of executions as his lawyers sought to obtain testing of dozens of pieces of crime scene evidence not previously tested. Among them were a bloody knife and bloodstains found throughout the victims' Pampa home. A windbreaker that Skinner's lawyers contended might have been worn by the killer disappeared from police custody and was not subjected to DNA testing. Earlier this year, Skinner's legal team argued to Pampa state District Judge Steven Emmert that the killings had been committed by Twila Busby's uncle, who reportedly accosted her at a party shortly before her death. In a one-page ruling, Emmert ruled that it was "reasonably probable" that the new DNA test results would not have … Continue reading →

PUBLIC RELEASE DATE: 16-Jul-2014 Contact: Saskia Rohmer saskia.rohmer@springer.com 49-622-148-78414 Springer Scientists now have a better understanding of how short DNA strands decompose in microseconds. A European team found new fragmentation pathways that occur universally when DNA strands are exposed to metal ions from a family of alkaline and alkaline earth elements. These ions tend to replace protons in the DNA backbone and at the same time induce a reactive conformation leading more readily to fragmentation. These findings by Andreas Piekarczyk, from the University of Iceland, and colleagues have been published in a study in EPJ D. They could contribute to optimising cancerous tumour therapy through a greater understanding of how radiation and its by-products, reactive intermediate particles, interact with complex DNA structures. In cancer radiation therapy, it is not the radiation itself that directly damages the DNA strands, or oligonucleotides. But rather, it is the secondary reactive particles, leading to the creation of charged intermediates. Here, the authors have studied one of these charged intermediates in the form of so-called protonated metastable DNA hexamers. To do so, the authors created selected oligonucleotide-metal-ion complexes that they selected to have between zero and six metal ions. They then followed these complexes' fragmentation … Continue reading →