Infections caused by microorganisms are a global public health problem that continually demands new antimicrobial strategies. The generation of reactive oxygen species (ROS) photocatalytic materials is an attractive approach to combat microbes. Along these lines, titanium dioxide (TiO2) constitutes outstanding light-driven ROS generator. However, the wide bandgap this semiconductor limits its u...

The photoinactivation of actively and nonactively growing herpes simplex virus by neutral red and proflavine was studied in rabbit kidney cells. Active virus growth was inhibited by both dyes under conditions which did not destroy the cells. Neutral red caused a much greater inhibition than proflavine. Neutral red also caused a reduction in the reactivation rate of latent virus when the infecte...

We studied the effect of low light intensity on Photosystem II (PSII) of thylakoid membranes isolated form spinach. The application of low frequency single turnover flashes results in the decreased oxygen evolving activity of PSII. This effect was explained in the framework of a model, which assumes that saturating visible light flashes at low frequency can result in the degradation of the D1 p...

Pyridoxal phosphate can act as a specific photosensitizer for amino acid residues in rabbit muscle and spinach leaf aldolases, but the residues affected depend on the pH of the reaction. Below pH 8 one histidine residue per enzyme subunit is destroyed; above pH 8.5 there is little loss of histidine, and photoinactivation is associated with the destruction of specific tyrosine residues, particul...

Antimicrobial photodynamic inactivation (APDI) combines a nontoxic photoactivatable dye or photosensitizer (PS) with harmless visible light to generate singlet oxygen and reactive oxygen species that kill microbial cells. Cationic phenothiazinium dyes, such as toluidine blue O (TBO), are the only PS used clinically for APDI, and we recently reported that this class of PS are substrates of multi...

A clinical trial was undertaken to compare the efficacy of neutral red photodynamic inactivation treatment of genital herpes infections with that of a non-photoactive dye, phenol red, as a control. In a series of nineteen patients with virologically proven herpes genitalis who were adequately followed, eleven were treated with neutral red, and eight with phenol red; no difference in response to...

AMPA receptors mediate the majority of the fast excitatory transmission in the central nervous system. Much evidence suggests that the fast trafficking of AMPA receptors into and out of the postsynaptic membrane underlies changes in synaptic strength thought to be necessary for higher cognitive functions such as learning and memory. Despite the abundance of research conducted in this area, a di...

Effects of red (600 to 680 nanometers) and far red (700 to 760 nanometers) irradiances on Amaranthus retroflexus L. seeds indicate that synthesis of phytochrome in the red-absorbing form takes place in water-imbibed nongerminating seeds at 35 C. After 96 hours in darkness, conversion of about 0.10% phytochrome to the far red-absorbing form induces 50% germination. Continuous far red radiation a...

The bacterial toxin colicin E1 is known to induce voltage-gated currents across a planar bilayer lipid membrane. In the present study, it is shown that the colicin-induced current decreased substantially upon illumination of the membrane in the presence of the photosensitizer, aluminum phthalocyanine. This effect was almost completely abolished by the singlet oxygen quencher, sodium azide. Usin...