Nguyen, T. L. A. | Search bioRxiv

bioRxiv2025

Asymmetric phosphoinositide lipid bilayers generated by spontaneous lipid insertion

Phosphatidylinositol phosphate (PIP) lipids, enriched on the cytoplasmic leaflet of the plasma membrane, are key regulators of diverse cellular processes, often through interactions with partner proteins that regulate actin assembly. Supported lipid bilayers (SLBs) provide a powerful model system to study the interactions of PIP lipids with their partner proteins. However, despite advances in SLB preparation methods, it remains a challenge to robustly obtain fluid SLBs in which PIP lipids are both mobile and asymmetrically distributed. In this study, we report a simple and robust method to generate asymmetric SLBs containing tunable amounts of PI(4,5)P2. By dissolving PI(4,5)P2 below its critical micelle concentration (CMC), we enable its spontaneous insertion into the upper leaflet of SLBs exposed to bulk solution. The mobility of PI(4,5)P2 is confirmed using fluorescence recovery after photobleaching (FRAP). Furthermore, we demonstrate that PI(4,5)P2 incorporated using this method retains its functionality, recruiting binding partners, actin-membrane linker ezrin, and myosin 1 motors capable of sliding actin filaments on the SLBs. Our method offers a straightforward strategy to generate asymmetric PI(4,5)P2-containing SLBs and is applicable to other lipid species with high CMC values.

biophysics↗

bioRxiv2023

Gut microbes contribute to variation in foraging intensity in the honey bee, Apis mellifera.

Gut microbiomes are increasingly recognized for mediating diverse biological aspects of their hosts, including complex behavioral phenotypes. While many studies have reported that experimental disruptions to the gut microbiome result in atypical host behavior, studies that address how gut microbes contribute to adaptive behavioral trait variation are rare. Eusocial insects represent a powerful model to test this, due to their simple microbiomes and complex division of labor characterized by colony-level variation in behavioral phenotypes. While previous studies report correlational differences in gut microbiome associated with division of labor, here, we provide evidence that gut microbes play a causal role in defining differences in foraging behavior between honey bees. Gut microbial community structure consistently differed between hive-based nurse bees and bees that leave the hive to forage for floral resources. These differences were associated with variation in the abundance of individual microbes, including Bifidobacterium asteroides, Bombilactobacillus mellis, and Lactobacillus melliventris. Manipulations of colony demography and individual foraging experience suggested that differences in microbiome composition were associated with task experience. Moreover, single microbe inoculations with B. asteroides, B. mellis, and L. melliventris caused changes in foraging intensity. These results demonstrate that gut microbes contribute to division of labor in a social insect, and support a role of gut microbes in modulating host behavioral phenotypic variation.

animal behavior and cognition↗