Dynamic laser speckle and fuzzy mathematical morphology applied to studies of chemotaxis towards hydrocarbons

Abstract

Abstract:The movement of the microorganisms towards a higher concentration of the chemical attractant is called positive chemotaxis and is involved in the efficiency of chemical degradation. Several studies are focused in this field related to genomics, and towards demonstrating chemotactic responses by bacteria, but there is little information related to the activity and morphology of their response. In this work, we use a recently reported dynamic speckle laser method, to process images and to distinguish motile surface patterns per area of colonisation by applying image processing techniques called fuzzy mathematical morphology (FMM). The images of bacterial colonies are usually surfaced, with vague edges and non-homogeneous grey levels. Hence, conventional image processing methods for shape analysis cannot be applied in these cases. In this paper, we propose the application FMM to solve this problem. The approach given was effective to segment, detect and also to describe colonisation patterns. 60M. Nisenbaum et al.

Video processing analysis for the determination and evaluation of the chemotactic response in bacterial populations

“…The processed images showed positive chemotaxis of P. aeruginosa strain H to glycerol, kerosene, 1-octene, 1-dodecene, and n-hexadecane in decreasing order of the response. These results confirm the chemotactic response of Polycystis aeruginosa strain H towards kerosene, 1-dodecene and n-hexadecane previously mention by Nisenbaum et al (2013Nisenbaum et al ( , 2014. The motility of the bacterial clusters around the plug for 1decene, 1-nonene and 1-undecene were lower than for the negative plug (showed in Fig.…”

“…The method presented in this work allows working with low cell concentration mainly due to the high selectivity of the processing which only uses movement objects in the frame. This is an advantage when researchers work with xenobiotic compounds which minimize the bacterial concentration (Nisenbaum et al, 2013(Nisenbaum et al, , 2014. Additionally, working with low bacterial concentrations is advantageous because metabolism of a chemoeffector is slow enough that chemoeffector gradients are not affected by metabolism.…”