RESUMEN
Oxidative stress can be regarded as an imbalance between the amount of reactive oxygen species (ROS) and the ability of a biological system to eliminate the toxic species and repair the resulting damages. Since the germinating seeds and the resulted seedlings are rich in enzymes, whereas the treatment with chemicals affects much the seed germination, producing also ROS, we evaluate here the influence of 2,4-dinitrophenol (DNP) and potassium iodate (KIO3) on wheat germination (Triticum aestivum L.) and seedlings growth. Germination rate, the masses and heights of the 7 day old seedlings, as well as the activity of some enzymes involved in the oxidative stress such as peroxidase, catalase and superoxide dismutase were measured seven days after the chemical treatment. The treatment of the wheat seeds with 10-5 - 10-3 M solutions of DNP resulted in a relative concentration-dependent inhibition of the germination, with a concomitant stimulation of the weight and height of viable seedlings. The Gasparom variety treated with 10-5 M KIO3 showed a slight increase in the germination rate in comparison with the control batch. The two tested substances determined a significantly modified response of the oxidative stress enzymes, especially in the seeds treated with 10-4 and 10-3 M solutions.
RESUMEN
In this review, we bring further evidence in support of the hypothesis on the socalled respiratory and pH imbalance (RpHI) as a cause of long standing hypoxia within the whole organism, characteristic to the preneoplastic stage. Background: Carcinogenesis is a process by which normal cells are transformed into cancer cells. Cancer is a multifactorial disease with contributions from environmental, genetic and lifestyle factors. Cancer prevention is a global priority, yet the proximate causes of most cancers are still little understood. However, under hypoxic conditions, the overbusy cells, getting less oxygen than needed, turn into anaerobic adenosine triphosphate (ATP) production, excessive multiplication and finally, tumor development. Since hypoxia depends on the intensity and duration of action of the stress agent, human and animal organisms may compensate hypoxia only if the causal agent stops acting continuously. Cancer prevention might be associated with an increase in oxygen delivery to overstressed cells, carbon dioxide removing, as well as pH and glucose concentration balancing. The role of RpHI in chemical carcinogenesis and cancer incidence is also discussed. Conclusion: Evidence from the literature data is brought to show that cancers develop at the physiological level, while the molecular changes in cancer cells are the consequence and not the main cause of malign processes. A link between the Warburg effect and the Macovschi’s biostructural theory was suggested.