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Malaria is a worldwide health problem with 225 million infections each year. A fast and easy-to-use method, with high performance is required to differentiate malaria from non-malarial fevers. Manual examination of blood smears is currently the gold standard, but it is time-consuming, labour-intensive, requires skilled microscopists and the sensitivity of the method depends heavily on the skills of the microscopist. We propose an easy-to-use, quantitative cartridge-scanner system for vision-based malaria diagnosis, focusing on low malaria parasite densities. We have used special finger-prick cartridges filled with acridine orange to obtain a thin blood film and a dedicated scanner to image the cartridge. Using supervised learning, we have built a Plasmodium falciparum detector. A two-step approach was used to first segment potentially interesting areas, which are then analysed in more detail. The performance of the detector was validated using 5 420 manually annotated parasite images from malaria parasite culture in medium, as well as using 40 cartridges of 11 780 images containing healthy blood. From finger prick to result, the prototype cartridge-scanner system gave a quantitative diagnosis in 16 min, of which only 1 min required manual interaction of basic operations. It does not require a wet lab or a skilled operator and provides parasite images for manual review and quality control. In healthy samples, the image analysis part of the system achieved an overall specificity of 99.999978% at the level of (infected) red blood cells, resulting in at most seven false positives per microlitre. Furthermore, the system showed a sensitivity of 75% at the cell level, enabling the detection of low parasite densities in a fast and easy-to-use manner. A field trial in Chittagong (Bangladesh) indicated that future work should primarily focus on improving the filling process of the cartridge and the focus control part of the scanner. [ABSTRACT FROM AUTHOR]

The spatial relationship, or degree of colocalization, between two or more types of molecules in live cells is commonly detected using fluorescence microscopy. This spatial distribution can be used to estimate the interaction between fluorescently labelled molecules. These interactions are usually quantified by analysing the correlation and/or the overlap between images, using the Pearson's and Manders' coefficients, respectively. However, the correlation and overlap coefficients are parameters not designed to quantify molecular interactions. Here we propose a new colocalization coefficient specifically designed to quantify the interactions between molecules. In well-defined thermodynamic ensembles, this coefficient can in principle be used to calculate relevant statistical thermodynamic quantities such as binding free energies. [ABSTRACT FROM AUTHOR]

Methods for the in-depth study of the physics of microscale actuation of microfluidics environments by flagellated bacteria ‘teamsters’ have been developed. These methods, which include single and multi-colour fluorescent labelling and electron microscopy allow for the analysis of the effect that individual flagellar filaments have on bacterially driven microstructures, and allow for the investigation of the interaction and coordination of flagellar filaments of neighbouring bacteria on densely packed monolayers of bacteria, ‘bacterial carpets’. We show that the flagella of bacteria that are immobilized on a surface often interact with each other, and that the flagella of these bacteria do not often form multi-flagella bundles that are aligned with the cell body. [ABSTRACT FROM AUTHOR]

Image-based, high throughput genome-wide RNA interference (RNAi) experiments are increasingly carried out to facilitate the understanding of gene functions in intricate biological processes. Automated screening of such experiments generates a large number of images with great variations in image quality, which makes manual analysis unreasonably time-consuming. Therefore, effective techniques for automatic image analysis are urgently needed, in which segmentation is one of the most important steps. This paper proposes a fully automatic method for cells segmentation in genome-wide RNAi screening images. The method consists of two steps: nuclei and cytoplasm segmentation. Nuclei are extracted and labelled to initialize cytoplasm segmentation. Since the quality of RNAi image is rather poor, a novel scale-adaptive steerable filter is designed to enhance the image in order to extract long and thin protrusions on the spiky cells. Then, constraint factor GCBAC method and morphological algorithms are combined to be an integrated method to segment tight clustered cells. Compared with the results obtained by using seeded watershed and the ground truth, that is, manual labelling results by experts in RNAi screening data, our method achieves higher accuracy. Compared with active contour methods, our method consumes much less time. The positive results indicate that the proposed method can be applied in automatic image analysis of multi-channel image screening data. [ABSTRACT FROM AUTHOR]

The point spread function (PSF) is of central importance in the image restoration of three-dimensional image sets acquired by an epifluorescent microscope. Even though it is well known that an experimental PSF is typically more accurate than a theoretical one, the noise content of the experimental PSF is often an obstacle to its use in deconvolution algorithms. In this paper we apply a recently introduced noise suppression method to achieve an effective noise reduction in experimental PSFs. We show with both simulated and experimental three-dimensional image sets that a PSF that is smoothed with this method leads to a significant improvement in the performance of deconvolution algorithms, such as the regularized least-squares algorithm and the accelerated Richardson–Lucy algorithm. [ABSTRACT FROM AUTHOR]

Summary We have found the nuclear stain DRAQ5 to decrease the cellular uptake of a series of boron dipyrromethane (bodipy)-labelled compounds. This phenomenon is consistent between Lysotracker Green DND 26, Lysotracker Red DND 99 and bodipy-labelled mycolactone. Although DRAQ5 uptake was not prevented, DRAQ5 was in significant excess in each case. As the effect is consistent among two cell types, RAW 264.7 monocyte/macrophages and Bend 3 endothelial cells, we hypothesize that it may be a result of the two dyes complexing in solution into a form that is not taken up by the cells. This hypothesis is confirmed by fluorescence resonance energy transfer analysis in solution. [ABSTRACT FROM AUTHOR]