A Molecular Approach to Palaeontology: Biochemical Method Applications of Brachiopod Proteins

This work represents a contribution to the larger project of applying immunological or biochemical techniques to gain access to the molecular structure of geological samples. Intra-crystalline molecules were extracted from various brachiopod shells and analysed using SDS-PAGE, which enables the estimation of their molecular weight. The separated molecules were further characterised by employing electroblotting on PVDF membrane and immunostaining techniques (Alkaline phosphatase-labeled antibody). Polyclonal sera were used in this work for their wide range of specificity. The body tissue homogenate of representatives of the two main brachiopod classes were also analysed and characterised using the above mentioned techniques. The amino acid content of the intra-crystalline shell extract and the body tissue homogenate samples were analysed using an ABI 420H analyser. The SDS-PAGE of each of Terebratulina retusa and Neocrania anomala present different separating pattern indicating dissimilarities in their molecular weight. Examined by SDS-PAGE Terebratulina retusa intra-crystalline shell extract displays one band at 29-36 k Da in molecular weight, while Neocrania anomala intra-crystalline shell extract did not show any band under such examination. However, the amino acid analysis of Neocrania anomala sample revealed a significant amount of each amino acid present. Great differences were found in the amino acid contents of the intra-crystalline shell extract of each of T. retusa and N. anomala. The above techniques were applied to hundreds of brachiopod samples and a standard or blank sample were always run according to each method