The radiant energy induced degradation at 293 K of isolated Dl/D2/cyt b559 complexes from spinách was investigated under aerobic conditions by measurements of absorption and emission spectra between 1.1 and 270 K. In the 1.1 K absorption spectrum a bleaching and slight blue shift at 679 nm and a blue shift of the 672 nm band was observed. In the emission spectrum deconvoluted into Gaussian bands, the major fluorescence band referred to as F682 was most susceptible to photodegradation: (7) At all temperatures F682 was blue shifted with respect to the control. (2) The half-width of F682 was temperature independent at T < 10 K and became significantly increased in damaged samples. (3) The temperature dependence of rp6g2 in the range of 10 K < T < 270 K was less pronounced in damaged samples. Our results support the idea of a multistep model of photodegradation with several intermediates in the pathway from the undamaged control into strongly damaged complexes. The temperature dependence of rp6g2 i® explained by contributions owing to static and dynamical inhomogeneous broadening. The static inhomogeneous broadening increases with progressing degradation. Furthermore, our results suggest that aerobic photodegradation of the Dl/D2/cyt 3559 complexes also causes modifications of the electron-phonon interactions. The frequency of the phonon mode dominating the electron phonon coupling decreases in damaged samples.
Background - There is growing interest in the role of microbial agents in the causation of psychiatric disorders. The neurotropic protozoan parasite Toxoplasma gondii is one of the main candidates and has been associated with various psychiatric conditions, including schizophrenia. Methods - A narrative review of the literature from the main medical databases (Medline, PubMed, PsycINFO), Google Scholar and Google using combinations of applicable terms. Results - T. gondii affects the brain in both the acute and the latent stages of infection causing apparent brain pathologies in infected rodents and both immuno-compromised and immuno-competent humans. In immuno-competent individuals, behavioural disorders are primarily related to the latent stages of the illness. Behavioural/mental disorders that include schizophrenia, mood disorders, personality changes and cognitive impairments may be related to infection with T. gondii. Evidence for a behavioural effect of T. gondii comes from observational reports in animal models and controlled behavioural analysis in humans. Indirect clues of infection also come from raised seroprevalence or serotitres of antitoxoplasma antibodies among those with mental disorders. The pathophysiologic mechanism through which T. gondii may exert its effect is not clear, but direct impact on the brain and changes in neuroimmunomodulation, neurotransmission and some gene-environment interactions are postulated. Conclusion - There is evidence supporting a potential role of T. gondii infection in the onset of some behavioural disorders. Confirmation of such a role would prove a significant breakthrough in the search for the aetiology, treatment and prevention of behavioural disorders, such as schizophrenia. However, the associations remain preliminary.