Analysis of plant cuticles and their interactions with agrochemical surfactants using a 3D printed diffusion chamber

BACKGROUND

Decades of research is available on their effects of single component surfactant on active ingredient diffusion across plant cuticular membranes, but ingredient diffusion is rarely analysed in the presence of commercial surfactants. Also, diffusion studies require expensive or specialized apparatus the  fabrication of which often requires skilled labour and specialized facilities. In this research we have addressed both problems where the effects of four commercially available surfactants on a known tracer molecule were investigated using a 3D printed customized diffusion chamber.

RESULTS

As a proof-of-concept a customized 3D printed diffusion chamber was devised using two different thermoplastics and was successfully used in a range of diffusion tests . The effect of various solvents and surfactants on S. lycopersicum cuticular membrane indicated an increased rate of flux of tracer molecules across the membranes. This research has validated the application of 3D printing in diffusion sciences and demonstrated the flexibility and potential of this technique.

CONCLUSIONS

Using a 3D printed diffusion apparatus, the effect of commercial surfactants on molecular diffusion through isolated plant membranes was studied. Further, we have included  here the steps involved in material selection, design, fabrication, and post processing procedures for successful recreation of the chamber. The customizability and rapid production process of the 3D printing demonstrates the power of additive manufacturing in the design and use of customizable labware.

Measuring the Co-Localization and Dynamics of Mobile Proteins in Live Cells Undergoing Signaling Responses

Single molecule imaging in live cells enables the study of protein interactions and dynamics as they participate in signaling processes. When combined with fluorophores that stochastically transition between fluorescent and reversible dark states, as in super-resolution localization imaging, labeled molecules can be visualized in single cells over time. This improvement in sampling enables the study of extended cellular responses at the resolution of single molecule localization. This chapter provides optimized experimental and analytical methods used to quantify protein interactions and dynamics within the membranes of adhered live cells. Importantly, the use of pair-correlation functions resolved in both space and time allows researchers to probe interactions between proteins on biologically relevant distance and timescales, even though fluorescence localization methods typically require long times to assemble well-sampled reconstructed images. We describe an application of this approach to measure protein interactions in B cell receptor signaling and include sample analysis code for post-processing of imaging data. These methods are quantitative, sensitive, and broadly applicable to a range of signaling systems.

Uncovering cellular networks in branching morphogenesis using single-cell transcriptomics

Single-cell RNA-sequencing (scRNA-seq) and related technologies to identify cell types and measure gene expression in space, in time, and within lineages have multiplied rapidly in recent years. As these techniques proliferate, we are seeing an increase in their application to the study of developing tissues. Here, we focus on single-cell investigations of branching morphogenesis. Branched organs are highly complex but typically develop recursively, such that a given developmental stage theoretically contains the entire spectrum of cell identities from progenitor to terminally differentiated. Therefore, branched organs are a highly attractive system for study by scRNA-seq. First, we provide an update on advances in the field of scRNA-seq analysis, focusing on spatial transcriptomics, computational reconstruction of differentiation trajectories, and integration of scRNA-seq with lineage tracing. In addition, we discuss the possibilities and limitations for applying these techniques to studying branched organs. We then discuss exciting advances made using scRNA-seq in the study of branching morphogenesis and differentiation in mammalian organs, with emphasis on the lung, kidney, and mammary gland. We propose ways that scRNA-seq could be used to address outstanding questions in each organ. Finally, we highlight the importance of physical and mechanical signals in branching morphogenesis and speculate about how scRNA-seq and related techniques could be applied to study tissue morphogenesis beyond just differentiation.

A diffusion-based approach for modelling crack tip behaviour under fatigue-oxidation conditions

Modelling of crack tip behaviour was carried out for a nickel-based superalloy subjected to high temperature fatigue in a vacuum and air. In a vacuum, crack growth was entirely due to mechanical deformation and thus it was sufficient to use accumulated plastic strain as a criterion. To study the strong effect of oxidation in air, a diffusion-based approach was applied to investigate the full interaction between fatigue and oxygen penetration at a crack tip. Penetration of oxygen into the crack tip induced a local compressive stress due to dilatation effect. An increase in stress intensity factor range or dwell times imposed at peak loads resulted in enhanced accumulation of oxygen at the crack tip. A crack growth criterion based on accumulated levels of oxygen and plastic strain at the crack tip was subsequently developed to predict the crack growth rate under fatigue-oxidation conditions. The predicted crack-growth behaviour compared well with experimental results.