Water assessment using ultra-weak bioluminescence.

In this paper a method to evaluate the presence of microorganisms of the coliform group in water samples using the ultra-weak bioluminescence (UWB) is proposed. A series of UWB measurements and optical density measurements from cultures of both a set of standard E. coli strain samples, and a set of water samples from a river near Curitiba City in Brazil were performed. All samples were previously incubated at 37°C for 11h in nutritive medium before the temporal UWB emission profiles data were acquired for a period of 24h inside a dark chamber of an especially implemented instrumentation capable of doing photon counting measurements. For the optical density measurements, a spectrophotometer was used to acquire the growth kinetics of those cultures for a period of 13h, and the results compared to the UWB profiles. Periodic time-components analysis of the UWB data from both the set of standard E. coli samples and the set of the river's water samples were performed and compared to each other. The results have shown that the UWB temporal profiles resemble in some way the growth kinetics curve and the periodic time-components analysis is an effective way to discriminate between contaminated and non-contaminated samples, therefore the method may be viable for detecting coliforms in water samples in less time than usual methods.

Acute stress in seedlings detected by ultra-weak photon emission.

The ultra-weak photon emission (biophoton) patterns of wheat germination tests under chemical stress (mercury and fluoride solutions) are presented in comparison to respective control groups run simultaneously in two similar, automatic photon-count chambers. Solutions of Hg (EC(50) and EC(100)) and NaF (EC(50)) were applied at the fourth day, after the first 72 h of imbibition in water, with photon-count experiments in controlled conditions. Seedlings' growth performance were checked by total mass increase as well as root development, and plotted against the respective angular factor of photon-count curve's linear regression. Both Hg and NaF series presented very distinguishable patterns when compared to each respective control groups. Higher counts appear all over the 24 h test for the Hg series and just in the first 6 h for the NaF series.