High-definition optical coherence tomography imaging for noninvasive examination of heritage works.

Cultural heritage works, such as ancient murals and historical paintings, are examined routinely for the purpose of conservation. Previous works have applied optical coherence tomography (OCT), which is a three-dimensional (3D) microscopic imaging modality in the field of heritage works conservation. The data acquired by OCT provides both 3D surface information of the object and structure information underneath the surface. Therefore, cross-sectional information on the object can be utilized to study layer structure of the painting and brush stroke techniques used by the artist. However, as demonstrated in previous studies, OCT has limited capability in high-definition (HD) examination of paintings or murals that are in macroscopic scale. HD examination of heritage works needs to scan large areas and process huge amounts of data, while OCT imaging has a limited field of view and processing power. To further advance the application of OCT in the conservation of heritage works, we demonstrate what we believe is a novel high-speed, large field-of-view (FOV) OCT imaging platform. Our results suggest that this OCT platform has the potential to become a nondestructive alternative for the analysis and conservation of paintings and murals.

Promoter Identification and Optimization for the Response of Lactobacillus plantarum WCFS1 to the Gram-Negative Pathogen-Associated Molecule N-3-Oxododecanoyl Homoserine Lactone.

Quorum sensing (QS) in bacteria has been well studied as a cellular communication phenomenon for decades. In recent years, such systems have been repurposed for the use of biosensors in both cellular and cell-free contexts as well as for inducible protein expression in nontraditional chassis organisms. Such biosensors are particularly intriguing when considering the association between the pathogenesis of some bacteria and their signaling intermediates. Considering this relationship and considering the recent demonstration of the species Lactobacillus plantarum WCFS1 as both a synthetic biology chassis and an organism capable of detecting a pathogen-associated QS molecule, we wanted to develop this organism as a QS sentinel. We used an approach combining techniques from both systems and synthetic biology to identify a number of native QS-response genes and to alter associated promoter activity to tune the output of L. plantarum cultures exposed to N-3-oxododecanoyl homoserine lactone. The resulting engineered QS sentinel reinforces the potential of modified lactic acid bacteria (LAB) for use in human-health-promoting applications and also demonstrates a simple rational workflow to engineer sentinel organisms to respond to any environmental or chemical stimuli.