A. Triglia

Reactive oxygen species levels and DNA fragmentation on astrocytes in primary culture after acute exposure to low intensity microwave electromagnetic field

The exposure of primary rat neocortical astroglial cell cultures to acute electromagnetic fields (EMF) in the microwave range was studied. Differentiated astroglial cell cultures at 14 days in vitro were exposed for 5, 10, or 20min to either 900MHz continuous waves or 900MHz waves modulated in amplitude at 50Hz using a sinusoidal waveform and 100% modulation index. The strength of the electric field (rms value) at the sample position was 10V/m. No change in cellular viability evaluated by MTT test and lactate dehydrogenase release was observed. A significant increase in ROS levels and DNA fragmentation was found only after exposure of the astrocytes to modulated EMF for 20min. No evident effects were detected when shorter time intervals or continuous waves were used. The irradiation conditions allowed the exclusion of any possible thermal effect. Our data demonstrate, for the first time, that even acute exposure to low intensity EMF induces ROS production and DNA fragmentation in astrocytes in primary cultures, which also represent the principal target of modulated EMF. Our findings also suggest the hypothesis that the effects could be due to hyperstimulation of the glutamate receptors, which play a crucial role in acute and chronic brain damage. Furthermore, the results show the importance of the amplitude modulation in the interaction between EMF and neocortical astrocytes.

INFLUENCE OF THE PRESENCE OF ATRAZINE IN WATER ON THE IN-VIVO DELAYED LUMINESCENCE OF ACETABULARIA ACETABULUM

Abstract This article shows that the photoinduced delay luminescence in the seconds time range emitted from a unicellular alga Acetabuluria acetabulum is influenced in selective way by the presence of atrazine in the matrix. The presence of atrazine is noticeable up to a concentration of about 0.5 μg l −1 . The presented phenomenon suggests the possibility of analyzing trace elements in water, destined to be used for drinking, using a physical parameter related to a biological system and could make possible the development of a new methodology for monitoring water pollution.

Analogous features of delayed luminescence from Acetabularia acetabulum and some solid state systems

This paper compares some features of the delayed luminescence in the seconds range emitted from an unicellular alga Acetabularia acetabulum and from some solid state systems. Results lead us to think that such delayed luminescence is connected to the dimension of the ordered structures present in both biological and solid state systems. In particular, for the biological system examined, these structures are thought to be those which contribute to the dynamic formation of the cytoskeleton.

Photon emission from normal and tumor human tissues

Photon emission in the visible and near ultraviolet range by samples of human tissue removed during surgery has been measured by means of a low noise photomultiplier coupled to a data acquisition system. The results show that among the 25 analyzed samples the 9 from normal tissues had an emission rate of the order of some tens of photons/cm2 min, while most of the 16 tumor tissue samples had a very much higher rate.

Role of water content in dielectric properties and delayed luminescence of bovine Achilles’ tendon

In order to investigate the role of water network in collagen structure, measurement of dielectric permittivity was performed on bovine Achilles’ tendon as a function of water content. The data show a sudden decrease of the permittivity at each measured frequency value when the tendon humidity decreases. A similar behaviour is shown by the total number of photons emitted in delayed luminescence (DL) experiments. The comparison of the two results is in agreement with the hypothesis that DL is connected to the excitation and subsequent decay of collective electronic states, whose properties depend on the organized structure of the system.

‘Simultaneous’ measurements of delayed luminescence and chloroplast organization in Acetabularia acetabulum

Abstract This paper reports results of ‘simultaneous’ measurements of chloroplast streaming and delayed luminescence of Acetabularia cells. We show that freezing in liquid nitrogen or incubation in chloroform affects significantly and rapidly both the organelle motility and delayed luminescence decay. Results suggest the idea that delayed luminescence is related to the integrity of the dynamic chloroplast organization.

Relation between delayed luminescence and functional state in soya seeds

SummaryThe possibility of using the parameters connected to delayed luminescence to detect thermal stress conditions in soya seeds is discussed here and the results of the measurement of photoinduced emission conducted on soya seeds characterized by a different vegetative vigour are presented. A phenomenological relationship between the total re-emission and the growth velocity was found. The distributions of the decay times relative to the different conditions of stress on the seeds have given indications towards the existence of different dynamics. On the basis of the results it seems that a correlation exists between the functional state of the seeds and delayed luminescence.

Delayed luminescence of microalgae as an indicator of metal toxicity

The delayed luminescence (DL) (i.e. the photo-induced photon emission long after the illumination is switched off) of unicellular green algae samples has been measured when different concentrations of heavy metals are added to the standard culture medium, with the aim of assessing the DL as a promising approach for assaying the toxicity of contaminants such as metals. In particular, samples of freshwater green micro-algae Selenastrum capricornutum have been used. Concentrations of cadmium, chromium, lead and copper, ranging from 10−5 to 10−2 M, have been tested. The analysis of the decay trends, in the time interval from tens of microseconds to seconds, of the DL spectral components demonstrates that the DL parameters are sensitive to the presence of such pollutants. More precisely, the performed analysis allowed us to determine phenomenological relationships between the DL parameters and the metal concentration that could be used in view of the possibility of realizing a biosensor for water pollution detection. Attempts to distinguish between different contaminants are also described. Results of this preliminary study show that the DL measure based technique is suitable as a general bioassay of metal contamination and it could also be used to test the efficiency in bioavailability studies.

Impedance spectroscopy of pure water in the 0.01 Hz to 100 kHz range

SummaryThe complex impedance of a water-filled cell has been measured in the frequency range between 0.01 Hz and 100 kHz at temperatures ranging between 5°C and 80°C. The obtained results have been interpreted according to the Gouy, Chapmann and Stern model describing the water behaviour in the presence of electrode interfaces. The deconvolution of the measured complex impedance allowed to separate the contribution arising from the «bulk» water from those due to the Helmholtz layer and to the diffuse charge layer occurring at the electrode interface. The capacitance and resistance of the three layers are reported and their frequency and temperature dependences are briefly discussed. The use of this method as a tool to investigate the low-frequency dielectric properties of water is suggested.

Influence of cations in extracellular liquid on delayed luminescence of Acetabularia acetabulum

Abstract This paper examines the effect of cations in the culture medium on the critical parameters of delayed luminescence of Acetabularia acetabulum that are correlated with morphological changes. We show that Ca2+ has drastic effects on the cell, causing rapid, irreversible contraction of the cytoskeleton and chloroplasts; these effects are only counteracted by the presence of Mg2+. Simultaneous alterations in the critical parameters of delayed luminescence offer important clues as to the source and nature of delayed luminescence and its link to the whole structure of the system.