Future studies should determine whether other enzymes of the siRNA/miRNA pathway are subject to sumoylation, and also reveal potential cross-talks between these modifications to regulate RNA interference. The copper ion plays a significant role in a number of physiological processes in living organisms, but is also an important environmental pollutant. Aberrant levels of Cu2+ ions can result in oxidative stress, and has been linked with the development of Indian childhood cirrhosis, prion disease, Menkes disease, Parkinson��s disease and Wilson disease. The upper limit for the concentration of copper in drinking water has been recommended to be 2 ppm by the World Health Organization. A number of Cu2+ -selective chemosensors that employ the chromogenic, fluorogenic, or electrochemical properties of molecules have been reported in the literature. However, these methods may require tedious sample pretreatment and/or multistep synthetic procedures, or they may be Oxycodone hydrochloride limited by an unstable detection signal. Therefore, the development of sensitive and selective sensors for Cu2+ ions is of high interest. The application of transition metal complexes as colorimetric and luminescent probes has recently attracted increasing attention due to their notable advantages. Firstly, the absorptive and emissive behaviour of transition metal complexes can be sensitive to changes in the surrounding environment, allowing changes in analyte concentration to be transduced into an SKF 96365 hydrochloride optical response. Secondly, metal complexes can possess significant Stokes shifts, allowing easy distinguishing of excitation and emission light. Third, the relatively long lifetimes of phosphorescent metal complexes compared to organic luminophores can allow interference from scattered light and short-lived background fluorescence to be reduced to a negligible level by use of time-resolved luminescence spectroscopy. Finally, the luminescence quantum yield of transition metal complexes can be enhanced by increased intersystemcrossing rates arising from strong spin-orbit interactions. Among transition metal complexes, octahedral d6 Ir complexes have gained particular interest due to their decent thermal stability, intense luminescence at ambient temperature, and absorption or emission wavelengths across the entire visible light region that can be adjusted by modification of the auxiliary ligands.