Magnetotropism: A tropic response of Candida guillemondii by the effect of the oscillating magnetic field of extremely low frequency

Abstract

Extremely low frequency oscillating magnetic field (OMF-ELF) can stimulate the growth of pathogenic fungi. This work aims to assess the tropic response of a dimorphic pathogenic strain Candida guilliermondii by the effect of OMF-ELF. The pathogenic strain C. guilliermondii was isolated from an indoor environment and a brewing strain Saccharomyces cerevisiae was used as a positive control. OMF-ELF of 3 mT of 60 Hz for 2 h was applied to the cultures of both strains. After treatment, images were taken every 30 min for 24 h using Digital Image Processing (DIP) to determine the superficial growth rate of both strains and the length of the pseudohyphae, and the tropic response of C. guilliermondii. However, C. guilliermondii showed a tropic response depending on the OMF-ELF applied growing 3 to 60 times faster than the control strain, with a maximum value of 1.27 μm2/min between 1.5 and 2.5 h. C. guillermondii is resistant to OMF-ELF, a factor that stimulated its superficial growth rate and the elongation of its pseudohyphae, facilitated its cellular dimorphism, and oriented its ramifications to increase reproduction. This increase constitutes a risk to human health indoor environments where there is microbiological and electromagnetic contamination. Due to the use of DIP in real time with an adapted microculture technique, this is the first study to analyze “in vivo” magnetotropism of C. guilliermondii, as indicative of its invasive behavior for a possible infestation to humans exposed to this type of non-ionizing radiation in an indoor environment.