Biology subjects

Merker, S.

Publications and source records attributed to Merker, S..

3 recordsLinked to original sources

bioRxiv2025

Chromosome segregation in Escherichia coli involves DNA binding by the MinC-MinD complex

The Escherichia coli Min system, composed of the proteins MinC, MinD, and MinE, is crucial for directing septum formation at mid-cell. MinD has also been shown to bind DNA in a non-sequence-specific manner and to tether plasmid DNA to liposomes. A role for the Min system in chromosome segregation has been proposed, whereby repeated, transient membrane-tethering events mediated by MinD could help prevent backward movements of the duplicated chromosomes once entropic forces weaken. However, the contribution of the other Min proteins to DNA binding has remained unclear. Here, we demonstrate that DNA binding is strongly enhanced when MinD and MinC form a complex, while MinE and FtsZ (at high concentrations) interfere with this binding. We reveal a critical role for the linker connecting MinCs N- and C-terminal domains in both DNA binding and inhibition of FtsZ polymerization. E. coli strains expressing MinC linker variants from the native locus, in combination with the alpha subunit of HU tagged with GFP, display chromosomes that appear more spread throughout the cell. This phenotype could reflect reduced compaction, chromosome segregation defects, or a combination of both. These findings suggest a previously unrecognized role for the MinC linker in DNA binding and provide new insights into a potential physiological role of MinCD-DNA bnding in chromosome organization and/or dynamics.

microbiology↗

bioRxiv2025

Scaly-Tail Organ Enhances Static Stability during Pel's Scaly-tailed Flying Squirrels' Arboreal Locomotion

Scaly-tailed squirrels (Anomaluridae) are one of the least studied mammalian families. Their namesake is due to a peculiar and unique scaly-tail organ extruding from the caudal vertebrate that has been predicted to help reduce skidding. This study investigates the function of the scaly-tail organ found in Anomalurus pelii, investigating its potential role in enhancing arboreal locomotion. As these animals glide from tree to tree in a habitat abundant with smooth-bark trees, we hypothesize that the scaly-tail organ assists with friction enhancement in their native smooth-bark habitat. Through a combination of analyses using mathematical and physical models for experimental validation, we explore whether the scaly-tail organ could improve the sliding and overturning stability during perching. Our experimental results showed that the scaly-tail organ can act as a skid-reduction mechanism by enhancing substrate engagement on intermediate roughness substrates by 58%. Mathematical models showed the scaly-tail organ enhances overturning stability by acting as an additional support point. Our model showed that the scaly-tailed squirrel can reach up to 82.5{whitebullet} inclination without claw force; however, without scales, it reduces to 79.6{whitebullet}. Overall, this research highlights the functional significance of scaly-tail organs in adaptations in scaly-tailed flying squirrels and contributes to our understanding of their locomotion strategies and environmental stresses. Our study also provides insights into innovative perching mechanisms for robots operating in arboreal environments.

bioengineering↗

bioRxiv2023

Adulis and the transshipment of baboons during classical antiquity

Adulis, located on the Red Sea coast in present-day Eritrea, was a bustling trading centre between the first and seventh centuries CE. Several classical geographers--Agatharchides of Cnidus, Pliny the Elder, Strabo--noted the value of Adulis to Greco-Roman Egypt, particularly as an emporium for living animals, including baboons (Papio spp.). Though fragmentary, these accounts predict the Adulite origins of mummified baboons in Ptolemaic catacombs, while inviting questions on the geoprovenance of older (Late Period) baboons recovered from Gabbanat el-Qurud ("Valley of the Monkeys"), Egypt. Dated to ca. 800-540 BCE, these animals could extend the antiquity of Egyptian-Adulite trade by as much as five centuries. To explore this possibility, we analysed complete mitochondrial genomes from a mummified baboon from Gabbanat el-Qurud and 14 museum specimens with known provenance together with published georeferenced mitochondrial sequence data. Phylogenetic assignment connects the mummified baboon to modern populations of Papio hamadryas in Eritrea and eastern Sudan. This result, assuming geographical stability of phylogenetic clades, suggests that present-day Eritrea, and by extension Adulis, was a source of baboons for Late Period Egyptians. It also establishes geographic continuity with baboons from the fabled Land of Punt (Dominy et al., 2020), giving weight to speculation that Punt and Adulis were essentially the same trading centres separated by a thousand years of history.

zoology↗