We describe methods for live-cell imaging of yeast cells that we have exploited to image yeast polarity establishment. As a rare event occurring on a fast time-scale, imaging polarization involves a trade-off between spatiotemporal resolution and long-term imaging without excessive phototoxicity. By synchronizing cells in a way that increases resistance to photodamage, we discovered unexpected ...

A short overview on 3D live cell imaging is given. Relevant samples are described and various problems challenges—including by optical sectioning, light scattering phototoxicity—are addressed. Furthermore, enhanced methods of wide-field or laser scanning microscopy together with some relevant examples applications summarized. In the future one may profit from a continuous increase in microscopi...

Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless agents results in the production of reactive species. This triggers a series of cellular events that culminate in the selective destruction of ca...

G-protein-coupled receptors (GPCRs) represent the major protein family for cellular modulation in mammals. Therefore, various strategies have been developed to analyze the function of GPCRs involving pharmaco- and optogenetic approaches [1, 2]. However, a tool that combines precise control of the activation and deactivation of GPCR pathways and/or neuronal firing with limited phototoxicity is s...

PEGylated chlorin e(6) photosensitizers were synthesized with tri(ethylene glycol) attached at the ester bond(s) for a 1:1 conjugate at the 17(3)-position, a 2:1 conjugate at the 15(2)- and 17(3)-positions, and a 3:1 conjugate at the 13(1)-, 15(2)-, and 17(3)-positions. These chlorin sensitizers were studied for hydrolytic stability and solubility, as well as ovarian OVCAR-5 cancer cell uptake,...

Patients treated with the immunosuppressant and anticancer drugs 6-thioguanine, azathioprine, or mercaptopurine can metabolize and incorporate them in DNA as 6-thioguanosine. The skin of these patients is sensitive to UVA radiation, and long-term treatment can result in extremely high incidence of sunlight-induced skin cancer. In this contribution the photophysics of 6-thioguanosine have been s...