Single-cell analysis tools for drug discovery and development

The genetic, functional or compositional heterogeneity of healthy and diseased tissues presents major challenges in drug discovery and development. Such heterogeneity hinders the design of accurate disease models and can confound the interpretation of biomarker levels and of patient responses to specific therapies. The complex nature of virtually all tissues has motivated the development of tools for single-cell genomic, transcriptomic and multiplex proteomic analyses. Here, we review these tools and assess their advantages and limitations. Emerging applications of single cell analysis tools in drug discovery and development, particularly in the field of oncology, are discussed

Ethylene metabolism in Pisum sativum L. : Kinetic parameters, the effects of propylene, silver and carbon dioxide and comparison with other systems

The kinetic parameters of in vivo ethylene metabolism by seedlings of Pisum sativum L. cv. Alaska have been determined. The oxidation of ethylene to CO2, (Ox) and the incorporation of ethylene into the tissue (TI) were both shown to display Michaelis-Menten kinetics (Km Ox = 0.9 × 10–6 M liquid phase, Vmax Ox = 2.4 × 10–10 moles g– dry mass h–1 Km TI = 1.6 × 10–6 M liquid phase, Vmax TI = 4.5 × 10–10 moles g–1 dry mass h–1). Propylene competitively inhibited both Ox (Ki = 7.0 × 10–6 M) and TI (Ki = 3.7 × 10–7 M). A system comparable to Ox was absent from imbibed cotyledons of Vicia faba L. cv. Aquadulce even at saturating concentrations of ethylene similar to those used in kinetic analysis on Pisum. Silver ions were shown to inhibit TI but promoted Ox, while carbon dioxide inhibited Ox but promoted TI. Kinetic data on both these effects are presented. Data on the effect of a range of concentrations of CO2 on TI and Ox are also presented