Characterization of Chromobacterium violaceum pigment through a hyperspectral imaging system

Abstract

In this paper, a comprehensive spatio-spectral and temporal analysis for Chromobacterium violaceum colonies is reported. A hyperspectral imaging (HSI) system is used to recover the spectral signatures of pigment production in a non-homogeneous media with high spectral resolution and high sensitivity in vivo, without destructing the sample. This non-contact sensing technique opens avenues to study the temporal growing of a specific section in the bacterial colony. Further, from a 580 [nm] and 764 [nm] spatio-spectral time series, a wild-type and mutant Chromobacterium violaceum strains are characterized. Such study provides quantitative information about kinetic parameters of pigment production and bacterial growing.

Isolation and characterization of Chromobacterium violaceum and antibacterial activities of its metabolite violacein

“…UV-Vis Spectrophotometry and quantification of violacein: UV-Vis spectroscopy (Hitachi U-2900 Double Beam Spectrophotometer, Japan) of violacein was performed in between wavelengths of 300 nm and 700 nm, with maximum absorbance recorded at 575 nm, a characteristic feature of this pigment (25) . The peak absorbance value was put into Beer-Lambert Law (A = εcl) for quantification, where 'A' is the absorbance at 575 nm, 'c' is the molar concentration, and 'ε' is the molar extinction coefficient of violacein at 575 nm (0.05601 ml μg −1 cm −1 ) (26) .…”

Enhanced elemental and mineralogical imaging of Cu-mineralized rocks by coupling μ-LIBS and HSI

“…Each sample was scanned one line at a time (push-broom configuration), by displacing the platform in an orthogonal trajectory, with respect to the axis used to encode the spectral information. 30 Finally, the original data was organized in a hypercube, which is composed of 800 × 900 spatial pixels ( x × y ) and 200 spectral bands ( λ ) for each sample. The region of interest was selected from the original hypercube and matched with the μ-LIBS imaging data.…”

Bioactive Natural Products: An Overview, with Particular Emphasis on Those Possessing Potential to Inhibit Microbial Quorum Sensing

“…For example, C. violaceum is among the most widely used bacteria in QS-related experiments, and it produces the violet pigment violacein. To avoid any notable interference from violacein, bacterial growth in this case can be quantified at 764 nm (Gallardo et al 2014), as violacein does not absorb at this wavelength. Similarly, appropriate wavelengths need to be selected while working with other pigmented bacteria.…”