The changing form of Antarctic biodiversity

Antarctic biodiversity is much more extensive, ecologically diverse and biogeographically structured than previously thought. Understanding of how this diversity is distributed in marine and terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of diversity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic biodiversity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewher

Functional characterisation of the haemoglobins of the migratory notothenioid fish Dissostichus eleginoides

This study addresses the primary structure, the oxygen-binding properties and the CO-rebinding kinetics of the haemoglobins of the Patagonian toothfish Dissostichus eleginoides. D. eleginoides belongs to the family Nototheniidae, the most diversified of the suborder Notothenioidei, mostly exhibiting an Antarctic distribution. Some of its features are typical of Antarctic species, some are not. For instance, D. eleginoides appears not to have functional antifreeze glycoproteins (consistent with its non- Antarctic distribution). In contrast, it has a major and a minor haemoglobin (similar to many Antarctic notothenioids), and their very low oxygen affinity does not follow the trend of other non-Antarctic notothenioids and appears typical of cold-adapted species. Moreover, the amino-acid sequence reveals high identity with the globins of Antarctic notothenioids, arguing in favour of a common origin within notothenioids, and indicates that the primary structure of the major and minor haemoglobins has undergone modifications only to a limited extent. The ligand-rebinding kinetics of the major haemoglobin of D. eleginoides indicate a strong stabilisation of the quaternary T state at lower pH values

Interaction of antifreeze proteins with water

Antifreeze proteins and antifreeze glycoproteins (AF(G)Ps) enable the survival of various cold-adapted organisms in freezing and subfreezing habitats by preventing the macroscopic growth of ice crystals. Regardless of their great structural diversity are all AF(G)Ps capable to adhere to growing ice crystals, a quality that is essential for their biological functions. Despite commercial interest and significant scientific breakthroughs has the precise working mechanism of antifreeze proteins not yet been unraveled. In this chapter we highlight the latest state-of-the art experimental and theoretical antifreeze protein research on the solution behavior of AF(G)Ps and their interaction with the solvent. Protein-water interactions are of general interest owing to the importance of protein hydration for the structure, stability, and activity of almost all proteins. We focus in particular on the direct interaction of AF(G)Ps with water and its role in the working mechanism of these unique proteins