Search

Images are at the core of most modern biological experiments and are used as a major source of quantitative information. Numerous algorithms are available to process images and make them more amenable to be measured. Yet the nature of the quantitative output that is useful for a given biological experiment is uniquely dependent upon the question being investigated. Here, we discuss the 3 main types of information that can be extracted from microscopy data: intensity, morphology, and object counts or categorical labels. For each, we describe where they come from, how they can be measured, and what may affect the relevance of these measurements in downstream data analysis. Acknowledging that what makes a measurement 'good' is ultimately down to the biological question being investigated, this review aims at providing readers with a toolkit to challenge how they quantify their own data and be critical of conclusions drawn from quantitative bioimage analysis experiments. [ABSTRACT FROM AUTHOR]

The article is an introduction to the second volume of "Women in Microscopy," which features a collection of papers on various microscopy techniques and technologies. The volume includes contributions on topics such as surface passivation, time-modulated structured illumination, Mesolens imaging, array tomography, and quantification in life sciences microscopy. The article also highlights the implementation of an interdisciplinary bootcamp at UC Berkeley aimed at promoting networking and support for women in microscopy. The bootcamp provides opportunities for undergraduate students to connect with women role models in academia and industry. Other papers in the volume discuss improvements in glass coatings for microscopy, a temporal method for improving localisation precision, mesoscale standing wave imaging, and array tomography in 3D electron microscopy. The volume concludes with a review on microscopy data quantification in the life sciences. Overall, the article showcases the diverse contributions of women in the field of microscopy and highlights the importance of supporting and promoting gender equity in the discipline. [Extracted from the article]

Modern research in the life sciences is unthinkable without computational methods for extracting, quantifying and visualising information derived from microscopy imaging data of biological samples. In the past decade, we observed a dramatic increase in available software packages for these purposes. As it is increasingly difficult to keep track of the number of available image analysis platforms, tool collections, components and emerging technologies, we provide a conservative overview of software that we use in daily routine and give insights into emerging new tools. We give guidance on which aspects to consider when choosing the platform that best suits the user's needs, including aspects such as image data type, skills of the team, infrastructure and community at the institute and availability of time and budget. [ABSTRACT FROM AUTHOR]

Living systems propagate by undergoing rounds of cell growth and division. Cell division is at heart a physical process that requires mechanical forces, usually exerted by assemblies of cytoskeletal polymers. Here we developed a physical model for the ESCRT-III-mediated division of archaeal cells, which despite their structural simplicity share machinery and evolutionary origins with eukaryotes. By comparing the dynamics of simulations with data collected from live cell imaging experiments, we propose that this branch of life uses a previously unidentified division mechanism. Active changes in the curvature of elastic cytoskeletal filaments can lead to filament perversions and supercoiling, to drive ring constriction and deform the overlying membrane. Abscission is then completed following filament disassembly. The model was also used to explore how different adenosine triphosphate (ATP)- driven processes that govern the way the structure of the filament is changed likely impact the robustness and symmetry of the resulting division. Comparisons between midcell constriction dynamics in simulations and experiments reveal a good agreement with the process when changes in curvature are implemented at random positions along the filament, supporting this as a possible mechanism of ESCRT-III-dependent division in this system. Beyond archaea, this study pinpoints a general mechanism of cytokinesis based on dynamic coupling between a coiling filament and the membrane. [ABSTRACT FROM AUTHOR]

Super-resolution microscopy techniques break the diffraction limit of conventional optical microscopy to achieve resolutions approaching tens of nanometres. The major advantage of such techniques is that they provide resolutions close to those obtainable with electron microscopy while maintaining the benefits of light microscopy such as a wide palette of high specificity molecular labels, straightforward sample preparation and live-cell compatibility. Despite this, the application of super-resolution microscopy to dynamic, living samples has thus far been limited and often requires specialised, complex hardware. Here we demonstrate how a novel analytical approach, Super-Resolution Radial Fluctuations (SRRF), is able to make live-cell super-resolution microscopy accessible to a wider range of researchers. We show its applicability to live samples expressing GFP using commercial confocal as well as laser- and LED-based widefield microscopes, with the latter achieving long-term timelapse imaging with minimal photobleaching. [ABSTRACT FROM AUTHOR]

The ability to accurately and reliably quantify viral infection is essential to basic and translational virology research. Here, we describe a simple and robust automated method for using fluorescence microscopy to estimate the proportion of virally infected cells in a monolayer. We provide details of the automated analysis workflow along with a freely available open-source ImageJ plugin, Infection Counter, for performing image quantification. Using hepatitis C virus (HCV) as an example, we have experimentally verified our method, demonstrating that it is equivalent, if not better, than the established focus-forming assay. Finally, we used Infection Counter to assess the anti-HCV activity of SMBz-CsA, a non-immunosuppressive cyclosporine analogue. [ABSTRACT FROM AUTHOR]

Summary Many biological structures take the form of fibres and filaments, and quantitative analysis of fibre organisation is important for understanding their functions in both normal physiological conditions and disease. In order to visualise these structures, fibres can be fluorescently labelled and imaged, with specialised image analysis methods available for quantifying the degree and strength of fibre alignment. Here we show that fluorescently labelled fibres can display polarised emission, with the strength of this effect varying depending on structure and fluorophore identity. This can bias automated analysis of fibre alignment and mask the true underlying structural organisation. We present a method for quantifying and correcting these polarisation effects without requiring polarisation‐resolved microscopy and demonstrate its efficacy when applied to images of fluorescently labelled collagen gels, allowing for more reliable characterisation of fibre microarchitecture. [ABSTRACT FROM AUTHOR]

Live-cell imaging has revolutionized our understanding of dynamic cellular processes in bacteria and eukaryotes. Although similar techniques have been applied to the study of halophilic archaea 1–5 , our ability to explore the cell biology of thermophilic archaea has been limited by the technical challenges of imaging at high temperatures. Sulfolobus are the most intensively studied members of TACK archaea and have well-established molecular genetics 6–9. Additionally, studies using Sulfolobus were among the first to reveal striking similarities between the cell biology of eukaryotes and archaea 10–15. However, to date, it has not been possible to image Sulfolobus cells as they grow and divide. Here, we report the construction of the Sulfoscope , a heated chamber on an inverted fluorescent microscope that enables live-cell imaging of thermophiles. By using thermostable fluorescent probes together with this system, we were able to image Sulfolobus acidocaldarius cells live to reveal tight coupling between changes in DNA condensation, segregation, and cell division. Furthermore, by imaging deletion mutants, we observed functional differences between the two ESCRT-III proteins implicated in cytokinesis, CdvB1 and CdvB2. The deletion of cdvB1 compromised cell division, causing occasional division failures, whereas the ΔcdvB2 exhibited a profound loss of division symmetry, generating daughter cells that vary widely in size and eventually generating ghost cells. These data indicate that DNA separation and cytokinesis are coordinated in Sulfolobus , as is the case in eukaryotes, and that two contractile ESCRT-III polymers perform distinct roles to ensure that Sulfolobus cells undergo a robust and symmetrical division. • Development of a heating chamber for live imaging of hyperthermophiles • Live imaging of cell division in the archaeon Sulfolobus acidocaldarius • DNA reorganization is tightly coupled to cell division in Sulfolobus acidocaldarius • ESCRT-III homologs play distinct roles in ensuring robust and symmetric division Pulschen et al. describe the "Sulfoscope," a microscopy platform that allows live imaging of hyperthermophiles. By imaging cell division in the archaeon Sulfolobus, they observe tight coupling between DNA reorganization and cytokinesis and complementary roles for two ESCRT-III homologs in ensuring robust and symmetric cytokinesis. [ABSTRACT FROM AUTHOR]