Biology subjects

Langer, M.

Publications and source records attributed to Langer, M..

3 recordsLinked to original sources

bioRxiv2026

ZmSWEET Sucrose transporters expressed in the endosperm adjacent to the maize embryo are necessary for carbon partitioning and embryo growth

In cereals such as maize, the kernel accumulates large quantities of storage compounds, including carbohydrates, lipids, and proteins, a process that requires tight regulation of nutrient transport. Seeds are composed of distinct tissues: the embryo, the endosperm, and maternal tissues that are symplastically isolated (not connected through plasmodesmata), necessitating specialized nutrient transfer mechanisms. In maize, nutrient transfer from maternal tissues to the endosperm via specialized basal endosperm transfer layer (BETL) cells is well characterized. However, nutrient transfer at the endosperm/embryo interface remains poorly understood. Consequently, the routes by which maternal carbon-derived sugars support embryo growth are still unclear. Our previous transcriptomic profiling uncovered a novel Endosperm domain Adjacent to the embryo Scutellum (EAS) with strong enrichment for transporter genes. Notably, genes encoding three sugar transporters from the SWEET (Sugars Will Eventually be Exported Transporters) family are highly and preferentially expressed in the EAS, suggesting the existence of a specialized sugar transfer mechanism at this interface. We show that the ZmSWEET proteins encoded by these genes are membrane-localized sucrose transporters and are functionally important for kernel development. A gene-edited triple zmsweet14a/14b/15a knock-out mutant exhibits reduced kernel weight and embryo size, significantly decreased embryo oil accumulation at maturity, and altered carbon partitioning within the kernel. In addition to these defects, mutant kernels display a significant reduction in primary root length during germination, indicating either lasting physiological consequences of disrupted sucrose transport during seed development or an additional role for these SWEET transporters during germination. Together, our findings demonstrate that sucrose transport at the endosperm/embryo interface is critical for proper carbon allocation, embryo development, and seed vigor, and identify the EAS as a key functional domain and potential target for improving seed composition.

plant biology↗

bioRxiv2026

COLLEMBOT: AI-Based Counting of Collembola for OECD 232 Tests

Ecotoxicological tests with soil organisms, such as the collembolan Folsomia candida, are essential for assessing chemical risks in terrestrial ecosystems. However, the current Organization for Economic Co-operation and Development (OECD) 232 reproduction tests rely on manual counting of juvenile and adult Collembola, a process that is costly, labor-intensive, time-consuming and prone to operator bias. These limitations restrict data availability and hinder robust risk assessments. We therefore developed COLLEMBOT, an automated counting tool based on a YOLOv11 convolutional neural network, designed to integrate seamlessly into OECD workflows without protocol modifications. The model was trained on high-resolution images (n = 3207) from multiple laboratories and validated using 22 independent datasets (n = 1704 images) from Amsterdam (Netherlands), Basel (Switzerland), Bayreuth (Germany), Coimbra (Portugal) and Aarhus (Denmark). Datasets consisted of relevant standard soils (OECD artificial soils with 2.5%, 5% and 10% sphagnum peat; LUFA 2.2) and the springtail Folsomia candida. Automated counts showed strong agreement with manual counts (R{superscript 2} = 0.88-0.99). Dose-response curves derived from automated and manual counts strongly overlapped and effect concentrations (EC and EC) differed minimally (Median %{Delta} 6.2 {+/-} 23 and EC10 - EC90 R2 [≥] 0.977), remaining within acceptable limits for regulatory risk assessment and confirming reliability. Time efficiency improved significantly: a test with [~]300 images and up to 1,500 individuals per image was processed in less than 3 hours, compared to [~]137 hours needed for manual counting, a reduction of approximately 97%. By reducing labor and improving reproducibility, COLLEMBOT enables broader hazard data generation for collembolans, supporting science-based chemical risk assessment. The code and workflow are publicly available to facilitate adoption and community-driven development. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=187 SRC="FIGDIR/small/697653v1_ufig1.gif" ALT="Figure 1"> View larger version (131K): org.highwire.dtl.DTLVardef@1d3ddc5org.highwire.dtl.DTLVardef@84c90aorg.highwire.dtl.DTLVardef@1aaf06aorg.highwire.dtl.DTLVardef@18ddfcd_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2023

Why are spontaneous bio photons observed only in living organisms? The key role of the proton current in ultra-weak photon emission

Light emission from living things is still at the centre of scientific interest. Ultra-weak photon emission (UPE) in the range from 300 to 900 nm has been discovered in living cells and organisms, including the human body 1. In general, so-called bio photons are attributed to life. Our recent studies on protonic p-n junction formation and light emission from electrically powered protonic p-n junction systems suggest, that UPE can be generated by excitations owing to proton current flow in living cells and sub-cellular structures (e.g. mitochondria), just like it is done in the case of laboratory protonic light-emitting diodes (H+LED) 2,3. While the emission of higher energy bio photons (above 3 eV, 200-420 nm wavelength) is mainly caused by radicals and reactive oxygen species (ROS) 1, 21, 32, 36, 37, 38, lower energy bio photons (below 3 eV, at 420 -1000 nm wavelength) should be associated with the excitation of the protonic system as a result of the flow of the proton current (discussed in this paper). We expect this to have important biomedical implications for diagnosis and therapy using UPE 36, 37. The similarity of H+LED and UPE spectra (Fig. 2) allows the use of protonic H+LED as a new broadband light source, ideally suited to mitochondria-oriented low-intensity light therapy 37. O_FIG O_LINKSMALLFIG WIDTH=174 HEIGHT=200 SRC="FIGDIR/small/557955v1_fig2.gif" ALT="Figure 2"> View larger version (38K): org.highwire.dtl.DTLVardef@4709b5org.highwire.dtl.DTLVardef@1ce7132org.highwire.dtl.DTLVardef@69b07forg.highwire.dtl.DTLVardef@c29245_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 2.C_FLOATNO Correspondence of the spectrum of ultra-weak photon emission UPE from the ventral side of the human finger (top; according to M. Kobayashi et al. 15) and our protonic H+LED 2. C_FIG Our results explain why spontaneous biophotons (UPE) are observed only in living organisms, tissues and cells 21. This is due to the constant flow of protons in the active ATP synthase/ATPase 23 and in the mitochondria in general 25-28, which is necessary both for life and for the emission of light (observed as bio photons).

biophysics↗