RT Journal Article
T1 Quantitative analysis of morphological changes in yeastcolonies growing on solid medium: the eccentricity andFourier indices
A1 Gil de Prado, Elena
A1 Rivas, Eva María
A1 Siloniz Jiménez, María Isabel de
A1 Diezma, Belén
A1 Barreiro, Pilar
A1 Martínez Peinado, José
AB The colony shape of four yeast species growing on agar medium was measured for 116 days by image analysis. Initially, all the colonies are circular, with regular edges. The loss of circularity can be quantitatively estimated by the eccentricity index, Ei, calculated as the ratio between their orthogonal vertical and horizontal diameters. Ei can increase from 1 (complete circularity) to a maximum of 1.17–1.30, depending on the species. One colony inhibits its neighbour only when it has reached a threshold area. Then, Ei of the inhibited colony increases proportionally to the area of the inhibitory colony. The initial distance between colonies affects those threshold values but not the proportionality, Ei /area; this inhibition affects the shape but not the total surface of the colony. The appearance of irregularities in the edges is associated, in all the species, not with age but with nutrient exhaustion. The edge irregularity can be quantified by the Fourier index, Fi , calculated by the minimum number of Fourier coefficients that are needed to describe the colony contour with 99% fitness. An ad hoc function has been developed in Matlab v. 7.0 to automate the computation of the Fourier coefficients. In young colonies, Fi has a value between 2 (circumference) and 3 (ellipse). These values are maintained in mature colonies of Debaryomyces, but can reach values up to 14 in Saccharomyces. All the species studied showed the inhibition of growth in facing colony edges, but only three species showed edge irregularities associated with substrate exhaustion.
PB John Wiley & sons
SN 1097-0061
YR 2014
FD 2014-11
LK https://hdl.handle.net/20.500.14352/34832
UL https://hdl.handle.net/20.500.14352/34832
LA eng
NO Universidad Complutense de Madrid-SCH
NO Ministerio de Educación, Cultura y Deporte (España)-FPU
NO PICATA fellowship of  Moncloa Campus of International Excellence (UCM-UPM).
DS Docta Complutense
RD 28 abr 2024