Biology subjects

Boettger, D.

Publications and source records attributed to Boettger, D..

4 recordsLinked to original sources

bioRxiv2026

UV photogrammetry for transparent and composite surfaces

Transparent and composite surfaces pose a fundamental challenge for stereo photogrammetry: optically smooth glass produces no detectable surface features under visible illumination, making three-dimensional reconstruction impossible without surface preparation. This excludes optical components such as lenses and cover glasses, composite assemblies, and semi-translucent biological specimens from non-contact geometric measurement. Here we show that coherent speckle illumination at 266 nm overcomes this limitation by exploiting wavelength-dependent scatter enhancement, generating sufficient backscattered signal on surfaces that are entirely invisible under visible illumination. We developed a multispectral stereo system and evaluated three illumination modalities under identical acquisition conditions. On transparent glass, both visible modalities produce complete reconstruction failure, recovering only non-transparent holder structures. Ultraviolet speckle illumination at 266 nm enables dense reconstruction of the same surfaces. We demonstrate recovery of an uncoated plano-convex lens with a fitted radius of 30.946 mm and point-cloud standard deviation of 106.5 {micro}m, defect detection on a transparent cover glass without surface preparation, and reconstruction of a semi-translucent biological specimen. On metrology-grade reference objects, ultraviolet speckle achieves a standard deviation of 116 {micro}m and completeness exceeding 93%, approaching the performance of optimised visible structured illumination. These results establish ultraviolet speckle photogrammetry as an enabling approach of optical metrology to otherwise uncooperative surfaces, with relevance to optical manufacturing inspection and biological surface analysis.

biophysics↗

bioRxiv2025

Applying telecentric stereo 3D-measurement to small Lepidopterans - bridging the macro and the microscale with isotropic micrometer resolution

We present a straightforward, application-driven telecentric stereo 3D-measurement system for high-precision measurements, designed for applications ranging from industrial quality control to biological research including scanning of Lepidoptera moths. Utilizing a dual-camera setup with telecentric lenses and structured illumination, our system achieves lateral resolution of 8.0 m and axial resolution of 4.46 m in a measurement volume of 11 mm x 11 mm x 6 mm. We address challenges typically encountered when using standard libraries like OpenCV, e.g. in extrinsic parameter estimation using a dedicated calibration method that corrects for a potential model mismatch due to telecentricity. Our approach adapts existing methods, such as telecentric stereo vision and structured illumination, into an optimized, user-friendly system tailored for life science research, enabling detailed 3D reconstructions of scattering objects, such as small moths, with isotropic micrometer accuracy. This work presents an application-driven approach for biological 3D metrology by integrating existing technologies (telecentric stereo vision, structured illumination) into a specialized imaging platform suitable for non-invasive morphological studies. Unlike conventional CT or microscopic approaches, our method provides a balance of precision, scalability, and practical usability for non-expert users with the aim to study developmental changes in species under varying environmental conditions, while also methodically bridging the gap between macroscopic and microscopic resolution in biological imaging.

biophysics↗

bioRxiv2025

A pivotal contribution of proteostasis failure and mitochondrial dysfunction to chromosomal instability-induced microcephaly

Mosaic variegated aneuploidy (MVA), a rare human congenital disorder that causes microcephaly, is characterized by extensive abnormalities in chromosome number and results from mutations in genes involved in accurate mitotic chromosome segregation. To characterize the cellular mechanisms underlying this disease, here we generated a Drosophila model of microcephaly caused by the depletion of a single spindle assembly checkpoint (SAC) gene in the neural stem cell (NSC) compartment. We present evidence that loss of stemness - compromised identity and proliferative capacity of NSCs- is the underlying cause of MVA and results in a reduced number of neurons and glial cells. We show that loss of stemness arises from the accumulation over time of an unbalanced number of gains and losses of more than one chromosome, rather than a direct consequence of chromosomal instability-induced DNA damage or the production of simple aneuploidies. We unravel that the negative impact of complex aneuploidies on stemness, a highly energy demanding cellular state, is a result of proteostasis failure and mitochondrial dysfunction. We identify autophagy activation--either directly or through TOR depletion--, overexpression of Radical Oxygen Species scavengers, and restoration of mitochondria proteostasis as genetic interventions capable of dampening the deleterious effects of aneuploidy on NSC identity and brain development. HighlightsSAC depletion in NSCs induces microcephaly through the production of complex aneuploidies Complex aneuploidies compromise the stemness of NSCs Loss of stemness results from proteostasis failure and mitochondrial dysfunction Boosting proteostasis or mitochondria homeostasis mitigate the negative effects on NSCs eTOC BlurbDepletion of the spindle assembly checkpoint in the neural stem cell compartment leads to microcephaly. Gonzalez-Blanco et al. provide evidence that proteostasis failure and mitochondrial dysfunction play a pivotal role in causing microcephaly by compromising the stemness of highly aneuploid neural stem cells.

neuroscience↗

bioRxiv2025

Do camera light traps for moths provide similar data as conventional funnel light traps?

O_LIInsects are of crucial importance for terrestrial ecosystems but many populations decline rapidly. Conventional collecting methods are usually time-consuming, resulting in a low temporal, spatial and taxonomic resolution of data. Automated camera light traps (CLT) allow non-lethal monitoring of species-rich moths (Lepidoptera) and other nocturnal insects, but so far little is known about their performance compared to conventional collecting methods. C_LIO_LIBy observing the behaviour of moths in previous field work, we hypothesized that CLT perform well in moth groups in which species tend to sit down quietly after approaching the lamp (such as Geometridae) but worse in moth groups in which species are persistently active (such as Sphingidae). C_LIO_LIWe tested the performance of two CLTs, equipped with Sony alpha 7II (24 megapixel sensor) cameras that resulted in images with approx. 420 dpi resolution. The study was carried out in a forested area near Bielefeld in NW Germany for 196 nights in a row from April to September 2023, and photos were taken every two minutes during the night. All macromoths recognizable in the photos were identified and counted individually. We directly compared the data from the CLTs with moth samples obtained from conventional funnel light traps (FLTs) during 12 nights which were spread across the flight season. C_LIO_LIThe resulting 420 dpi images from the CLTs allowed reliable species identification of all observed macromoths with only few exceptions due to technical problems. In direct comparison during 12 nights, CLTs recorded 39 species exclusively, FLTs recorded 48 species exclusively, and 53 species were recorded by both methods equally. During the whole sampling period of 196 nights in a row, a total of 225 moth species were recorded by CLTs. CLTs tended to record Geometridae better than FLTs whereas Sphingidae tended to be undersampled by the new method. Familes differed in the length to which they remained on the screen of the CLTs. C_LIO_LIOur study is the first to systematically compare the methods and it shows that CLTs perform overall very well. Results from CLTs differ to a certain extent from conventional trapping methods because they seem to perform worse in groups with highly active species and perform better in calmer groups like geometrid moths. CLTs are promising devices for insect monitoring since they deliver data with high resolution in time, space and taxonomy. The use of artificial intelligence (AI) for the analysis of images is intended as the next logic step. C_LI

ecology↗