Probing the effect of tip pressure on fungal growth: Application to Aspergillus nidulans

External signal-mediated polarized growth in fungi

As the majority of fungi are nonmotile, polarized growth in response to an external signal enables them to search for nutrients and mating partners, and hence is crucial for survival and proliferation. Although the mechanisms underlying polarization in response to external signals has commonalities with polarization during mitotic division, during budding, and fission growth, the importance of diverse feedback loops regulating external signal-mediated polarized growth is likely to be distinct and uniquely adapted to a dynamic environment. Here, we highlight recent advances in our understanding of the mechanisms that are crucial for polarity in response to external signals in fungi, with particular focus on the roles of membrane traffic, small GTPases, and lipids, as well as the interplay between cell shape and cell growth.

Comparison of cell mechanical measurements provided by Atomic Force Microscopy (AFM) and Micropipette Aspiration (MPA)

A comparative analysis of T-lymphocyte mechanical data obtained from Micropipette Aspiration (MPA) and Atomic Force Microscopy (AFM) is presented. Results obtained by fitting the experimental data to simple Hertz and Theret models led to non-Gaussian distributions and significantly different values of the elastic moduli obtained by both techniques. The use of more refined models, taking into account the finite size of cells (simplified double contact and Zhou models) reduces the differences in the values calculated for the elastic moduli. Several possible sources for the discrepancy between the techniques are considered. The analysis suggests that the local nature of AFM measurements compared with the more general character of MPA measurements probably contributed to the differences observed.

Advances in Micropipette Aspiration: Applications in Cell Biomechanics, Models, and Extended Studies

With five decades of sustained application, micropipette aspiration has enabled a wide range of biomechanical studies in the field of cell mechanics. Here, we provide an update on the use of the technique, with a focus on recent developments in the analysis of the experiments, innovative microaspiration-based approaches, and applications in a broad variety of cell types. We first recapitulate experimental variations of the technique. We then discuss analysis models focusing on important limitations of widely used biomechanical models, which underpin the urge to adopt the appropriate ones to avoid misleading conclusions. The possibilities of performing different studies on the same cell are also considered.