New techniques for the recovery of small amounts of mature enamel proteins

Currently there are no non-destructive techniques to obtain protein from the dental enamel, the most mineralized tissue in mammals and most resistant to diagenesis, which provides a window to the developing period by means of incremental markings containing proteins. To recover protein, dissolution of powdered enamel is required. Here we tested whether samples obtained by micro-etching of the enamel surface were adequate for protein analysis by MALDI-TOF/TOF mass spectrometry and identification in protein databases. The micro-etch techniques were effective in generating adequate samples for mass spectrometry (from 3 to 13.4 μm superficial enamel), being also highly conservative, since they rendered masses of enamel ranging from 0.1 to 0.4 mg. Using these techniques the separation of proteins by SDS-PAGE was not necessary, and the whole procedure was easier. Results showed successful identification of specific enamel proteins after whole crown superficial etching with 11% EDTA in the case of immature porcine samples, and with 10% HCl in the case of mature human enamel. X- and Y-isoforms of amelogenin, ameloblastin, and enamelin peptides were identified. The new techniques described here allowed the successful recovery of enamel proteins, opening new avenues for the use of enamel protein information in fossil/archeological material, where sometimes little protein is left.     

Political tourism in the Israeli‐Palestinian space (Respond to this article at http://www.therai.org.uk/at/debate)

With the violent clashes that took place in May 2010 during the attempt by the Free Gaza movement flotilla to break the blockade of the Gaza Strip, the remarkable strength of pro‐Palestinian networks became globally apparent. Drawing on an ethnography of political activism in the Israeli‐Palestinian space, we suggest that the striking visibility of these networks does not exclusively derive from the prominence of the Israeli‐Palestinian conflicts, but is also a consequence of the activists’ ability to produce innovative forms of sociality. However, some of the approaches taken can exist in problematic relation to the experiences of people who live with the conflict. In this context, the issue is not so much the precise relationships between indigenous ‘truths’ in Palestine and their foreign representations, but the way in which encounters redefine the conflicts that activist networks seek to represent.