Despite its vital role in advancing live cell imaging (LCI) and unraveling the complex processes that control cellular function, fluorescence microscopy presents challenges for the researcher, including labeling agents that can interfere with normal molecular activities, and limitations on repeat measurements and long-term studies from photobleaching and phototoxicity phenomena. Holotomography microscopy delivers nanoscale, label-free, real-time LCI and can combine this quantitative phase imaging (QPI) with fluorescence for state-of-the-art spatiotemporal resolution as well as high molecular specificity. This article introduces QPI, examines its advantages for LCI, and reviews correlative microscopy studies in cell pathophysiology in combination with fluorescence.

Investigation of the Fezouata Shale has added to our knowledge on the initial diversification of metazoans. These Lower Ordovician deposits yielded abundant and diverse remains of cuticularized to lightly sclerotized organisms, in addition to numerous soft tissues. Described fossilized soft parts recovered from the Fezouata Shale belong mainly to arthropods. Soft tissues in echinoderms, a main component of the Fezouata Biota, remain largely unexplored. Here, we show that soft tissue-like impressions previously reported in eocrinoid and somasteroid echinoderms from this formation, are the results of modern weathering and fossil preparation that involved the use of latex molds: they do not reflect any original (soft) anatomical features of these organisms. These two examples suggest that reports of putative soft parts, especially in taxa with no current representatives, need to be thoroughly and critically evaluated.

A method was developed to expedite the imaging of diatoms by optimizing their orientation. This quick technique puts grooves into a SEM stub so that as the diatoms are laid down they either land on the flat surface or in a variety of positions in the grooves, thereby reducing time required to capture taxonomically critical features.