Meeting Abstract
Artemia franciscana is an anhydrobiotic crustacean that survives extreme desiccation, osmotic stress, and severe cold during its encysted life-history stage. During this stage, A. franciscana expresses intrinsically-disordered polypeptides termed late embryogenesis abundant (LEA) proteins and accumulates trehalose. Trehalose is a non-reducing disaccharide known to enter a glassy state at low water contents. To examine the impacts of LEA proteins from A. franciscana on cellular structure, Kc167 cells from D. melanogaster were transfected with one of two genes encoding for group 3 LEA proteins (AfrLEA2 or AfrLEA3m). Transgenic and control cells were desiccated in presence and absence of trehalose using anhydrous calcium sulfate and examined using scanning electron microscopy (SEM), or Raman microspectroscopy (RS). SEM demonstrated that, in absence of trehalose, cells expressing AfrLEA2 maintained a larger diameter compared to both control and AfrLEA3m expressing cells. However, cells expressing AfrLEA3m maintained higher degrees of membrane integrity in the desiccated state compared to both control and AfrLEA2 expressing cells. In presence of 100 mM or 200 mM trehalose, control cells maintained higher degrees of membrane integrity, but had a smaller diameter than in absence of trehalose. Both transgenic cell lines maintained higher degrees of membrane integrity in the presence of trehalose than control cells and maintained a larger diameter. Interestingly, transgenic cells lost more water during desiccation than control cells according to RS measurements. Our results suggest that LEA proteins significantly impact cellular structure in the desiccated state (NSF IOS-1456809/1457061).
