The interaction between synaptic and electronic excitation of cells from the salivary gland of the snail Helisoma trivolvis was studied using a voltage-sensitive merocyanine dye. Linear and square photodiode matrix arrays were used to record simultaneously the response to neuronal stimulation of 15-25 separate regions of the gland. Laterally opposed acini exhibited highly synchronous electrical...

Background: Chromomycin A3 (CMA3) staining, with the slide method or fluorescence microscopy, is widely used for indirect assessment of protamine deficiency in a semen sample. Flow cytometry is the most suitable tool which to improve assessment accuracy, both in terms of statistical analysis and to prevent observer variation. This study provides a simple procedure to account for merocyanine 540...

The excited-state dynamics of two donor-acceptor biaryls that differ by the strength of the acceptor, a pyridinium or a pyrylium moiety, have been investigated using a combination of steady-state solvatochromic absorption, ultrafast fluorescence, as well as visible and infrared transient absorption spectroscopies. The negative solvatochromic behavior of pyridinium phenolate indicates that the p...

We report molecular-fluorescence enhancement via the blue-shifted plasmon-induced resonance energy transfer (PIRET) from single Au nanorods (AuNRs) to merocyanine (MC) dye molecules. The blue-shifted PIRET occurs when there is a proper spectral overlap between the scattering of AuNRs and the absorption of MC molecules. Along with the quenching of scattering from AuNRs, the blue-shifted PIRET en...

A photochromic polymer exhibiting mechanochromic behavior is prepared by means of ring-opening polymerization (ROP) of epsilon-caprolactone by utilizing a difunctional indolinospiropyran as an initiator. The configuration of having the photochromic initiating species within the polymer backbone leads to a mechanochromic effect with deformation of polymer films leading to ring-opening of the spi...

If the interplay between caspase proteases and mitochondria decide the fate of the cell during apoptosis, they may constitute useful molecular targets for novel drug design. We have shown that photoactivated merocyanine 540 (pMC540) triggers caspase-mediated apoptosis in HL60 leukemia and M14 melanoma cells. Because pMC540 is a mixture of photoproducts, we set out to purify the biologically act...

By means of recording a simple serie of merocyanine 540 spectra, we present a method to calculate the value proportional to co-operative unit size of membranes (n). Our calculations, applied to different liposomal samples processed in the presence or absence of sugars, in high or low ionic strength showed two main results. First, that any temperature cycling in high ionic strength of rigid DPPC...

The objective of this study was to investigate the response of Na(+)/K(+)-ATPase of human erythrocytes to green laser irradiation. Effects of green laser light of fluences 9.5-63.3 J.cm(-2) and merocyanine 540-mediated laser light treatment were studied. Isolated erythrocyte membranes (protein concentration of 1 mg/ml) were irradiated by Nd:YAG laser (532 nm, 30 mW) and then incubated in a medi...