Temperature-induced response in algal cell surface properties and behaviour: an experimental approach

Abstract

Microalgae are considered an accurate indicator of ecosystem perturbations induced by global climate change. The present work aims to investigate the alteration of temperature on surface properties and behaviour of three algal species using the complementary surface methods (electrochemical and atomic force microscopy). The results showed that the temperature-induced response of algae is species-specific due to the structural features of the cell envelope. Wall-less algae experience the largest nanomechanical and chemical change, while algae with silicified walls show the pronounced chemical change in the degree of hydrophobicity. Alterations of surface properties suggest a molecular modification of the algal barrier and cytoskeletal rearrangements due to a change in cell size, while algal morphology reveals no change. The physiological activity of cells showed a different organisation of released extracellular substances in the form of fine fibrillar structures, aggregated particles, and dense networks. Both types of algal responses, physiological activity, and molecular modification of the cell barrier determine the cell adhesion and motility. This study highlights the role of surface properties in cell-substrate and cell–cell interactions, which is important for the understanding of algal behaviour at natural interfaces and the mechanism of algal biofilm and aggregate formation in aquatic systems under the stress. Graphical abstract

Nanoplastic-Induced Nanostructural, Nanomechanical, and Antioxidant Response of Marine Diatom Cylindrotheca closterium

“…Another important property of the cell surface that may change, depending on growth conditions, is the rigidity of the cell wall. Indeed, several studies have shown that a specific stress or a change in environmental conditions (such as a change in pH, temperature, or salinity) can have an important effect on the composition or remodeling of the cell wall, thereby changing its nanomechanical properties [60][61][62][63][64][65][66]. Our nanoindentation measurements, performed on C. closterium cells exposed to nanoplastics, showed a significant decrease in cell wall rigidity compared to cells grown without nanoplastics (Figure 7).…”

“…A change in the Young modulus of cells was also observed when the pH of the culture medium changed, and it increased significantly at a higher pH [61]. In addition, previous studies by our group [64,65,68] have shown that the exposure of cells to temperature stress, salinity stress, and cadmium causes changes in cell rigidity, as a consequence of a molecular modification to the cell barrier. It is therefore not surprising that exposure to nanoplastics also alters the nanomechanical properties of cells.…”

Emerging Technologies for the Discovery of Novel Diversity in Cyanobacteria and Algae and the Elucidation of Their Valuable Metabolites

“…In fact, Novosel et al (2022) employed AFM to examine how temperature affected Dunaliella tertiolecta, Tetraselmis suecica and Cylindrotheca closterium. The results revealed that all three algae maintained their shape at different temperatures and exhibited no distinctive morphological changes at the cell surface.…”

“…Studying algal cell morphology was facilitated by AFM, which does not require a vacuum environment for imaging, unlike electron microscopy. This renders it possible to image cells that do not retain their morphology under a vacuum environment [24].…”

Tracking the Spatio-Temporal Distribution of Organic Particles to Predict Macroaggregation in the Northern Adriatic Sea

“…Our recent studies have shown that the adaptive response of microalgae to stress is speciesspecific and stressor-dependent. It seems that diatoms are more resistant to changes in temperature and salinity, with the cell wall having an important protective function in contrast to naked flagellates [25,26]. The adaptive response of microalgae exposed to drops in salinity or in temperature is manifested by an increase in cell stiffness or a change in hydrophobicity due to changes at the molecular level.…”