21 Mar 2023

Characterization of Pigmented Microbial Isolates for Use in Material Applications

Abstract: Organisms (i.e., plants and microorganisms) contain pigments that allow them to adapt and thrive under stressful conditions, such as elevated ultraviolet radiation. The pigments elicit characteristic spectral responses when measured by active and passive sensors. This research study focused on characterizing the spectral response of three organisms and how they compared to background spectral signatures of a complex environment. Specifically, spectra were collected from a fungus, a plant, and two pigmented bacteria, one of which is an extremophile bacterium. The samples were measured using Fourier transform infrared spectroscopy and discriminated using chemometric means. A top-down examination of the spectral data revealed that organisms could be discriminated from one another through principal component analysis (PCA). Furthermore, there was a strong distinction between the plant and the pigmented microorganisms. Spectral differences resulting in samples with the highest variance from the natural background were identified using PCA loading plots. The outcome of this work is a spectral library of pigmented biological candidates for coatings applications.

1 Oct 2020

Microbiological Indicators Reflect Patterns of Life

Abstract:  Resolving patterns of human movement, specifically for actors of interest, in an urban environment is an extremely challenging problem because of the dynamic nature of human movement. This research effort explores a highly unconventional approach, addressing residual or lingering signatures of interest to the Army in an urban operation. Research suggests that unconventional signatures commonly associated with human presence or prior occupation of a space, such as microbes attached to skin cells or in the gut, may linger for an extended amount of time. In this scoping study, our objectives were to detect microbial communities in the built environment, to examine microbial community composition, and to investigate the longevity of a microbial signature. To do so, we conducted a controlled study to obtain a mechanistic understanding of the fidelity of the biological signatures in the built environment, with a particular focus on their longevity and stability.