Temporal Variations of Skin Pigmentation in C57Bl/6 Mice Affect Optical Bioluminescence Quantitation

ABSTRACT PURPOSE: Depilation-induced skin pigmentation in C57Bl/6 mice is a known occurrence, and presents a unique problem for quantitative optical imaging of small animals, especially for bioluminescence. The work reported here quantitatively investigated the optical attenuation of bioluminescent light due to melanin pigmentation in the skin of transgenic C57B1/6 mice, modified such that luciferase expression is under the transcription control of a physiologically and pharmacologically inducible gene. PROCEDURE: Both in vivo and ex vivo experiments were performed to track bioluminescence signal attenuation through different stages of the mouse hair growth cycle. Simultaneous reflectance measurements were collected in vivo to estimate melanin levels. RESULTS: Biological variability of skin pigmentation was found to dramatically affect collected bioluminescent signal emerging through the skin of the mice. When compared to signal through skin with no pigmentation, the signal through highly-pigmented skin was attenuated an average of 90%. Correlation of reflectance signals to bioluminescence signal loss forms the basis of the proposed correction method. We observed, however, that variability in tissue composition, which results in inconsistent reflectance spectra, limits the accuracy of the correction method but can be improved by incorporating more complex analysis. CONCLUSION: Skin pigmentation is a significant variable in bioluminescent imaging, and should be considered in experimental design and implementation for longitudinal studies, and especially when sensitivity to small signal changes, or differences among animals, is required

Role of microbes in plant protection using intersection of nanotechnology and biology

Published online: 15 Aug 2018Plant pathogens are one of the dominating components which restrain crop productivity. Preliminary step headed for managing plant disease is to accurately recognize the pathogen under lab, glasshouse, and field conditions. Modern approach, such as culture-based, antibody-based rapid methods and quantitative polymerase chain reaction (Q-PCR), entrusts on multiple assays to precisely identify the specific plant pathogens which are further time-consuming and lack high sensitivity. Nanobiotechnology ameliorates crop productivity through transmission of genes to target sites for breeding of varieties resistant to different plant pathogens with focus on improving sensitivity. Intersection of nanotechnology and biology also improves specificity and agility of pathogen detection which further facilitates crop disease management. Bio-fabrication of nanoparticles like silver (Ag) and copper (Cu) is used as novel antimicrobials for the management of pathogenic microorganisms that inhibits fungal hyphae and conidial germination in agricultural crops. Biological agents reduce metal which leads to capping of nanoparticles through the secretion of various enzymes. A modern class of protein nanocompartments called as encapsulins that encapsulate cargo proteins are found in bacteria and archaea. Nanobiotechnology also reduces detection times of crop pathogens and cost by the development of biosensors and phage proteins. In this chapter we emphasize on microbial semblance in nanobiotechnology applications that precede to integrated disease management of agricultural crops including precise diagnostic layout of plant diseases and modification of crop environments to adversely affect crop pathogens