Biology subjects

Schilling, T.

Publications and source records attributed to Schilling, T..

3 recordsLinked to original sources

bioRxiv2026

Why Life is Hot

The process of evolution by natural selection leads to phenotypes of increasing fitness. For cellular chemical reaction networks, this means optimising a variety of fitness functions such as robustness, precision, or sensitivity to external stimuli. We argue that these diverse goals can be achieved by a versatile, generic mechanism: coupling chemical reaction networks to reservoirs that are strongly out of equilibrium. Using theory and numerics we show that this mechanism of optimisation comes at the price of significant heat dissipation. We compute the heat flux caused by kinetic proofreading in Escherichia coli and show that it constitutes a significant fraction of the total heat flux experimentally measured in this model organism. We then demonstrate that the degree of optimality achievable saturates, and that Nature appears to operate near saturation despite high energetic costs. We argue that `life is hot' largely because of the need for a versatile mechanism to optimise a variety of fitness functions.

biophysics↗

bioRxiv2024

Columnar cholinergic neurotransmission onto T5 cells of Drosophila

Several nicotinic and muscarinic acetylcholine receptors (AChRs) are expressed in the brain of Drosophila melanogaster. However, the contribution of different AChRs to visual information processing remains poorly understood. T5 cells are the primary motion-sensing neurons in the OFF pathway and receive input from four different columnar cholinergic neurons, Tm1, Tm2, Tm4 and Tm9. We reasoned that different AChRs in T5 postsynaptic sites might contribute to direction selectivity, a central feature of motion detection. We show that the nicotinic nAChR1, nAChR4, nAChR5 and nAChR7 subunits localize on T5 dendrites. By targeting synaptic markers specifically to each cholinergic input neuron, we find a prevalence of the nAChR5 in Tm1-, Tm2- and Tm4-to-T5 synapses and of nAChR7 in Tm9-to-T5 synapses. Knock-down of nAChR4, nAChR5, nAChR7, or mAChR-B individually in T5 cells alters the optomotor response and reduces T5 directional selectivity. Our findings indicate a differential contribution of postsynaptic receptors to input visual processing and, thus, to the computation of motion direction in T5 cells.

neuroscience↗

bioRxiv2021

In vivo macromolecular crowding is differentially modulated by Aquaporin 0 in zebrafish lens: insights from a nano-environment sensor and spectral imaging.

Macromolecular crowding is crucial for cellular homeostasis. In vivo studies of macromolecular crowding and ultimately water-dynamics are needed to understand their role in cellular fates. The macromolecular crowding in the lens is essential for understanding normal optics of the lens, and moreover for understanding and prevention of cataract and presbyopia. Here we combine the use of the water nano-environmentally sensitive sensor (6-acetyl-2-dimethylaminonaphthalene, ACDAN) with in vivo studies of Aquaporin zero zebrafish mutants to understand the lens macromolecular crowding. Spectral phasor analysis of ACDAN fluorescence reveal the extent of water dipolar relaxation and demonstrate that the mutations in the duplicated zebrafish Aquaporin 0s, Aqp0a and Aqp0b, alter the water state and macromolecular crowding in the living zebrafish lens. Our results provide in vivo evidence that Aqp0a promotes fluid influx in the deeper lens cortex, whereas Aqp0b facilitates fluid efflux. This work opens new perspectives for in vivo studies on macromolecular crowding. TeaserIn this study we uncover the roles of Aquaporin 0 in macromolecular crowding required for lens development and vision.

biophysics↗