Vesicle transport and growth dynamics in Aspergillus niger: Microscale modeling of secretory vesicle flow and centerline extraction from confocal fluorescent data. Issue 9 (27th June 2020)

• Record Type: Journal Article
• Authors: Kunz, Philipp J.; Barthel, Lars; Meyer, Vera; King, Rudibert
• Is Part Of: Biotechnology and bioengineering. Volume 117:Issue 9(2020)
• Page Start: 2875
• Page End: 2886
• Publication Date: 2020-06-27
• Subjects: Aspergillus niger -- filamentous fungi -- germ tube -- modeling -- protein secretion -- secretory vesicle; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.27452
• Languages: English
• ISSNs: 0006-3592

Abstract

Abstract: In this paper, we present a mathematical model to describe filamentous fungal growth based on intracellular secretory vesicles (SVs), which transport cell wall components to the hyphal tip. Vesicular transport inside elongating hyphae is modeled as an advection–diffusion–reaction equation with a moving boundary, transformed into fixed coordinates, and discretized using a high‐order weighted essentially nonoscillatory discretization scheme. The model describes the production and the consumption of SVs with kinetic functions. Simulations are subsequently compared against distributions of SVs visualized by enhanced green fluorescent protein in young Aspergillus niger hyphae after germination. Intensity profile data are obtained using an algorithm scripted in ImageJ that extracts mean intensity distributions from 3D time‐lapse confocal measurement data. Simulated length growth is in good agreement with the experimental data. Our simulations further show that a decrease of effective vesicle transport velocity towards the tip can explain the observed tip accumulation of SVs. Abstract : Centerline extraction algorithm based on confocal fluorescent image data (measured in CLSM), schematic view: (a) input: stacked time series of single conidium with germ tube, prefiltered, (b) sum projection ( z ‐wise) of N th time frame, (c) centerline extraction according to skeletonization pipeline (see (h)), (d) straightening along the skeleton in xy plane, (e) sum of projection in w, (f) centerline extraction, (g) straightening along the skeleton in the y ˜ z ˜ plane, (h) extraction of mean intensities on x ˜ z ˜ planes orthogonal to y ˜ results in mean centerline intensity as a function of the hyphal length, and (i) skeletonization pipeline: thresholding, radius estimation with tubeness ImageJ plug‐in (Rueden et al., 2017), skeletonization and centerline extraction