Growth behavior of microorganisms using UV‐Vis spectroscopy:Escherichia coli

Abstract

Multiwavelength transmission spectra of microorganisms and cell suspensions consist of combined absorption and scattering phenomena resulting from the interaction of light with microorganisms or cells typically suspended in a nonabsorbing media. The distribution of intensities as a function of wavelength depends on the size, shape, and optical properties of the sample. The optical properties are functions of the chemical composition and the state of aggregation, or association, of the chromophoric groups contained in the microorganisms. This article explores the growth behavior of Escherichia coli from the perspective of multiwavelength UV-Vis spectroscopy. Experimentally, it is demonstrated that the spectral signatures of the microorganism evolve as a function of time. It is also demonstrated that the spectral changes observed during growth are consistent with data reported elsewhere. From the theoretical point of view, it is demonstrated that the spectral signatures can be adequately represented with an interpretation model based on light-scattering theory. The parameters from the interpretation model reflect changes in size and chemical composition known to take place in the microorganisms during growth.

A new method for the detection of microorganisms in blood cultures: Part I. Theoretical analysis and simulation of blood culture processes

“…11–12). In addition, the effect of the chemical composition is introduced directly through the additive properties of the complex refractive index (Alupoaei and Garcia‐Rubio, 2004, 2005; Alupoaei et al, 2004). The reflectance model is comprehensive relative to the measurement variables.…”

“…The basic elements of the model, cell respiration and equilibrium considerations, have been tested against experimental data obtained in our laboratories and at Los Alamos National Laboratories (Claro Scientific, 2008, unpublished data). The logistic growth model is well accepted in the literature (Madigan et al, 2000) and has been successfully tested against measured particle count data from pure culture batch experiments (Alupoaei, 2001; Alupoaei et al, 2001, 2002a,b; Garcia‐Rubio et al, 2005). The respiration rates of leukocytes and platelets used in our model are consistent with those reported in literature.…”

Deep ultraviolet mapping of intracellular protein and nucleic acid in femtograms per pixel

“…For the most part, the underlying assumptions are identical to those applied in “gold standard” methods for quantifying protein and nucleic acids in bulk solution (3, 25). …”

Detection and Analysis of Biological Agents

“…Whether this kind of spectroscopy is sufficiently specific for biological identification has yet to be evaluated. For more details on this topic please refer to Reference [27,28].…”