From ARBRE-MOBIEU networking to regional research cooperation: Multimethod study of algal cell response to laboratory-induced cadmium stress

ARBRE-MOBIEU served as the platform to initiate a new research collaboration between partners from Croatia, Czech, Hungary and Slovakia which led to a joint project funded by International Visegrad Fund. In the frame of the corresponding project, we examined algal cells’ responses to laboratory-induced cadmium stress, focusing on the biointerface and intracellular changes by employing a multimethod approach. The biointerface is characterized in terms of surface properties (cell stiffness) and adhesion dynamics on a single cell level. The intracellular response was examined in terms of the cells’ autonomous feature (autofluorescence) and protein expression obtained from the cell culture. The results show that in spite of very a high cadmium concentration and prolonged cell exposure, the cells grew without significant suppression of growth dynamics. Cell adaptation to cadmium stress is manifested through cell shape deterioration, slower motility and an increase of physiological activity. AFM measurements revealed that cells are significantly stiffer in the presence of cadmium, which influenced the dynamics of the initial contact of the cell at the interface. The difference in adhesion behaviour was determined to be two times slower for initial attachment and deformation, while rate-limiting steps referring to the spreading of released intracellular content are not significantly different in comparison with the control. There was no change in the endogenous fluorescence in the red region (associated with chlorophyll) but there was a change in the green region (possibly associated with cadmium vesicular transport and beta carotene production), which provides insight into the cells’ adaptation strategy to maintain photosynthesis. Specific responses of natural fluorescence of cells under the influence of cadmium are most likely associated with the identified chlorophyll a-b binding protein. It seems that another identified protein, carbonic anhydrase, plays role in the photosynthetic pathway. Since production of these proteins can be related to the maintenance of the photosynthesis representing one of the cell defence mechanisms, it may also indicate the presence of toxic metal in seawater. This multimethod study enabled us to better understand cell responses under laboratory-induced cadmium stress to predict the fate of algae in a marine environment. Our results will substantially contribute to the biophysics of algal cells on a fundamental level. References [1] N. Ivošević DeNardis, J. Pečar Ilić, I. Ružić, N. Novosel, T. Mišić Radić, A. Weber, D. Kasum, Z. Pavlinska, R. Katalin Balogh, B. Hajdu, A. Marček Chorvatova, B. Gyurcsik, Algal cell response to laboratory-induced cadmium stress: a multimethod approach, Eur. Biophys. J. 48, 2019, 231-248.