Changes in ATP level and iron-induced ultra-weak photon emission in bull spermatozoa, caused by membrane peroxidation during thermal stress.

ATP level, cell motility and viability, oxygen uptake, pyruvate kinase activity, and ultra-weak photon emission (UPE) induced by red-ox Fe(2+)-ascorbate cycling system were studied in fresh, in previously equilibrated in a glycerol diluent, and in cryopreserved bull spermatozoa, exposed to thermal stress by incubation of the cells at 44 degrees C. A sharp drop in motility and viability of fresh spermatozoa and even more so, of equilibrated and cryopreserved cells was accompanied by accumulation of ATP. When cell movement was totally inhibited, ATP utilization was decreased, while chemical energy continued to be produced by cell pyruvate kinase, one of the key glycolytic enzymes, which in spermatozoa is very active (6500 IU/g protein) and insensitive to feed-back inhibition by excess of ATP and L-cysteine. Accumulation of ATP during incubation at 44 degrees C in 0.9% NaCl was accompanied by rapid decrease in oxygen consumption by fresh spermatozoa and an increase in Fe(2+)-ascorbate induced UPE, followed by a sharp decrease in ATP level observed at the end of induced UPE measurement. The increase in photon emission due to lipid peroxidation was highly correlated with the increase in cell ATP level caused by thermal stress.

Stress-induced photon emission from perturbed organisms.

This paper reviews an ultraweak luminescent response of selected biological systems (lower and higher plants, insects and spermatozoa) to certain kinds of detrimental mechanical, temperature, chemical and photochemical stress and to lethal factors. The enhancing effect of white light and formaldehyde on the ultraweak luminescence of yeast and spermatozoa cells is described for the first time. An increase in the percentage of long wavelengths (lambda > 600 nm) with an increase in reaction time, and a significant influence of the suspending medium on the ultraweak luminescence, were observed. The vitality and motility of bull spermatozoa and the vitality of yeast cells were drastically decreased by treatment with white light, water, formaldehyde and iron-ions. Successive irradiation of intact bull spermatozoa cells with white light caused an increase in the intensity of delayed luminescence. An attempt has been undertaken to find stochastic models of non-stationary photon emission. The quasi-relaxation descending stage of non-stationary processes can be modeled as the Integrated Moving Average process IMA (0, 1, 1), and memory and transfer functions can describe the degree of perturbation in the yeast Saccharomyces cerevisiae. The relation of the ultraweak luminescence response to perturbations of homeostasis is discussed in the framework of biochemical and physical models.