Our Changing World for Thursday 29 July 2010
Marine Bacteria and Decomposition
Gemma Dickson with three pig heads in cages
University of Otago PhD student Gemma Dickson, is trying to understand the role bacteria play in marine decomposition, to create a better "post-mortem clock" and help forensic scientists determine the length of time a body has been submerged.
To do this, she's been studying the DNA of bacteria on pigs' heads immersed in cages in Otago Harbour, and has so far found that bacteria from the environment do colonise both pigs and humans submerged remains. She has also found that there is a clear pattern of succession in bacterial colonisation with characteristic groups for early, mid and late submersion intervals. She is hopeful that the data generated from pigs will be translatable to humans and is also working with the New Zealand Police Dive Squad and has been asked to comment on fatalities during her PhD.
Bite Marks and Bacteria
Bite marks are common in some of the most serious of crimes, such as sexual assault and child abuse, but current methods of analysing bite marks are somewhat subjective. The most objective test is if DNA from the biter can be recovered from a bite mark, but enzymes in saliva degrade DNA so this method is often unsuccessful.
University of Otago PhD student Darnell Kennedy, is analysing the DNA from streptococci from bite marks to see if they can be matched to bacteria obtained from biters' teeth with the aim of creating a more objective test.
Science Learning Hub
Head to Our Changing World's audio archive and you will see these words: 'the spur for making this back catalogue available was an agreement signed in 2007 between Radio New Zealand and Waikato University, which runs the Biotechnology Learning Hub and the Science Learning Hub. These online databases provide specialised access to the programme content for teachers and school pupils throughout New Zealand.' To celebrate nearly five years of archived audio (totalling almost 1000 stories), Alison Ballance talks with University of Waikato Dean of Science Alister Jones to find out more about the Science Learning Hub.
Otago Museum's Natural Sciences Collection
The Otago Museum has been exhibiting The Vault, a behind-the-scenes look at the collections of various museums and galleries throughout New Zealand. Neil Pardington's large format photographs have been supplemented with some of the treasures from the museum's own basement collections. To find out more about what lurks in the museum basement, Alison Ballance enlists natural sciences curator Cody Fraser (pictured above left. Image: Otago Museum) for a tour of the vault. As well as meeting some of the collection's treasures, she finds out about techniques and methods for ensuring the longevity of the specimens. Note that The Vault exhibition only runs until 1 August, but you can arrange to have your own basement tour by contacting the Visitor Programmes Co-ordinator at Otago Museum.