Multi-well plates are convenient tools to work with in biology experiments, as they allow the probing of multiple conditions in a compact and economic way. Although both free and commercial software exist for the definition of plate layout and management of plate data, we were looking for a more flexible solution, available anywhere, free from download, installation and licensing constraints. In this context, we created PlateEditor, a free web-based, client-side application allowing rapid creation of even complex layouts, including dose-response curves and multiple combination experiments for any plate format up to 1536 wells. PlateEditor also provides heatmap visualization and aggregation features to speed-up the process of data analysis and formatting for export in other application. Written in pure JavaScript, it is fully open-source, can be integrated in various workflows and has the potential to be extended with more functionalities in the future.

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Cytidine deaminase (MtCDA), encoded by cdd gene (Rv3315c), is the only enzyme identified in nucleotide biosynthesis pathway of Mycobacterium tuberculosis that is able to recycle cytidine and deoxycytidine. An M. tuberculosis knockout strain for cdd gene was obtained by allelic replacement. Evaluation of mRNA expression validated cdd deletion and showed the absence of polar effect. MudPIT LC-MS/MS data indicated thymidine phosphorylase expression was decreased in knockout and complemented strains. The cdd disruption does not affect M. tuberculosis growth both in Mid- dlebrook 7H9 and in RAW 264.7 cells, which indicates that cdd is not important for macrophage invasion and virulence.

Para-aminosalicylic acid (PAS) is an antibiotic that was largely used for the multi-therapy of tuberculosis in the twentieth century. To try to overcome the inconvenience of its low efficacy and poor tolerance, we searched for novel chemical entities able to synergize with PAS using a combination screening against growing axenic Mycobacterium tuberculosis. The screening was performed at a sub-inhibitory concentration of PAS on a library of about 100,000 small molecules. Selected hit compounds were analyzed by dose–response and further probed with an intracellular macrophage assay. Scaffolds with potential additive effect with PAS are reported, opening interesting prospects for mechanism of action studies. We also report here evidence of a yet unknown bio-activation mechanism, involving activation of pyrido[1,2-a]pyrimidin-4-one (PP) derivatives through the Rv3087 protein.

Luminometer and imaging systems are used to detect and quantify low light produced by a broad range of bioluminescent proteins. Despite their everyday use in research, such instruments are costly and lack the flexibility to accommodate the variety of bioluminescence experiment formats that may require top or bottom signal acquisition, high or medium sensitivity, or multiple wavelength detection. To address the growing need for versatile technologies, we developed a highly customizable bioluminescence imager called Biolum’ RGB that uses a consumer color digital camera with a high-aperture lens mounted at the bottom or top of a 3D-printed dark chamber and can quantify bioluminescence emission from cells grown in 384-well microplates and Petri dishes. Taking advantage of RGB detectors, Biolum’ RGB can distinguish spectral signatures from various bioluminescence probes and quantify bioluminescence resonant energy transfer occurring during protein–protein interaction events. Although Biolum’ RGB can be used with any smartphone, in particular for low bioluminescence signals, we recommend the use of recent digital cameras which offer better sensitivity and high signal/noise ratio. Altogether, Biolum’ RGB combines the benefits of a plate reader and imager while providing better image resolution and faster acquisition speed, and as such, it offers an exciting alternative for any laboratory looking for a versatile, low-cost bioluminescence imaging instrument.