Biology subjects

Mayer, F.

Publications and source records attributed to Mayer, F..

11 recordsLinked to original sources

bioRxiv2026

The life cycle of an archaeon with multiple membranes

Many prokaryotes are diderms. They divide using an FtsZ division ring to simultaneously constrict physically coupled inner and outer membranes to form daughter cells with two membranes. Currently, only one archaeon, Ignicoccus hospitalis, is known to have an outer and inner membrane. Here, in exploring Ignicoccus cell division, we show by expansion microscopy that I. hospitalis uses a contractile CdvA-ESCRT-III ring to repeatedly constrict and cut its inner membrane in a way that yields clusters containing multiple cytoplasms within a shared periplasm. The outer bounding membrane then bursts to release the progeny cells, which regain their parental cell architecture via a membrane duplication process. Furthermore, this life cycle appears conserved across Ignicoccus strains, even though the precise timing of events changes. Taken together, these data show that Ignicoccus cells propagate by undergoing dynamic changes in their architecture as they transit between single and multi-cellular states.

cell biology↗

bioRxiv2026

Platelet Molecular Maturation Links Platelet Aging and the Platelet Storage Lesion

Human platelets change over their 7-10 day lifespan, yet the molecular mechanisms underlying platelet aging remain poorly defined. Using two independent RNA sequencing datasets of fluorescence-activated cell sorted young and old human platelets, we developed a unified transcriptomic model to characterize RNA metabolism across the platelet lifespan, which we termed platelet molecular maturation. This was applied to RNA sequencing data from room-temperature stored platelets (up to 7 days) and cold-stored platelets (7, 14, or 21 days). We identified highly concordant aging signatures, including 6,015 shared expressed genes and 2,008 shared differentially expressed genes (DEGs) with strongly correlated fold changes, demonstrating a conserved platelet aging program. Nucleotide-level analyses revealed preferential 3'-directed degradation among downregulated transcripts during endogenous platelet aging and room-temperature storage, supporting an organized RNA decay process that was correlated with platelet function changes. Room-temperature storage recapitulated platelet molecular maturation, showing concordance with aging-related gene expression changes and enrichment of downregulated gene sets. In contrast, cold-storage significantly attenuated platelet molecular maturation and 3'-directed degradation. A total of 669 genes were consistently differentially expressed between room-temperature and cold-stored platelets, while no DEGs were detected during cold-storage, indicating transcriptional stability. Platelet transcript stability in cold-storage correlated with preserved platelet hemostatic function. These findings establish platelet molecular maturation as a conserved, functionally relevant model linking endogenous platelet aging to platelet storage lesions and providing mechanistic insight into preserved platelet hemostatic function in cold-storage. This atlas of platelet RNA metabolism supports biomarker discovery and strategies to improve storage. KEY POINTSO_LIBy integrating multiple high-quality RNA sequencing datasets with novel analytic approaches tailored to the biology of anucleate platelets, we show that platelet aging is not a passive process of transcript decay, but follows a structured and reproducible molecular trajectory both endogenously and in storage, which we term platelet molecular maturation. C_LIO_LIStorage temperature emerged as a dominant modifier of this trajectory, with cold-storage markedly slowing RNA metabolic kinetics and preserving transcripts associated with younger, more hemostatically competent platelets. C_LIO_LITogether, these findings provide mechanistic insight into the platelet storage lesion and identify transcriptomic features that may serve as biomarkers or therapeutic targets to extend platelet shelf life. C_LI

genomics↗

bioRxiv2024

The best of two worlds: using stacked generalization for integrating expert range maps in species distribution models

Species distribution models (SDMs) are powerful tools for assessing suitable habitat across large areas and at fine spatial resolution. Yet, the usefulness of SDMs for mapping species realized distributions is often limited, since data biases or missing information on dispersal barriers or biotic interactions hinder them from accurately delineating species range limits. One way to overcome this limitation is to integrate SDMs with expert range maps, which provide coarse-scale information on the extent of species ranges that is complementary to information offered by SDMs. Here, we propose a new approach for integrating expert range maps in SDMs based on an ensemble method called stacked generalization. Specifically, our approach relies on training a meta-learner regression model using predictions from one or more SDM algorithms alongside the distance of training points to expert-defined ranges as predictor variables. We demonstrate our approach with an occurrence dataset for 49 bat species covering four biodiversity hotspots in the Eastern Mediterranean, Western Asia, and Central Asia. Our approach offers a flexible method to integrate expert range maps with any combination of SDM modeling algorithms, thus facilitating the use of algorithm ensembles. In addition, it provides a novel, data-driven way to account for uncertainty in expert-defined ranges not requiring prior knowledge about their accuracy, which is often lacking. Our approach holds considerable promise for better understanding species distributions, and thus for biogeographical research and conservation planning. In addition, our work highlights the overlooked potential of stacked generalization as an ensemble method in species distribution modeling.

ecology↗

bioRxiv2024

Long-read sequencing and genome assembly of natural history collection samples and challenging specimens

Museum collections harbor millions of samples, largely unutilized for long-read sequencing. Here, we use ethanol-preserved samples containing kilobase-sized DNA to show that amplification-free protocols can yield contiguous genome assemblies. Additionally, using a modified amplification-based protocol, employing an alternative polymerase to overcome PCR bias, we assembled the 3.1 Gb maned sloth genome, surpassing the previous 500 Mb protocol size limit. Our protocol also improves assemblies of other difficult-to-sequence molluscs and arthropods, including millimeter-sized organisms. By highlighting collections as valuable sample resources and facilitating genome assembly of tiny and challenging organisms, our study advances efforts to obtain reference genomes of all eukaryotes.

genomics↗

bioRxiv2020

Genome Methylation Predicts Age and Longevity of Bats

Exceptionally long-lived species, including many bats, rarely show overt signs of aging, making it difficult to determine why species differ in lifespan. Here, we use DNA methylation (DNAm) profiles from 712 known-age bats, representing 26 species, to identify epigenetic changes associated with age and longevity. We demonstrate that DNAm accurately predicts chronological age. Across species, longevity is negatively associated with the rate of DNAm change at age-associated sites. Furthermore, analysis of several bat genomes reveals that hypermethylated age- and longevity-associated sites are disproportionately located in promoter regions of key transcription factors (TF) and enriched for histone and chromatin features associated with transcriptional regulation. Predicted TF binding site motifs and enrichment analyses indicate that age-related methylation change is influenced by developmental processes, while longevity-related DNAm change is associated with innate immunity or tumorigenesis genes, suggesting that bat longevity results from augmented immune response and cancer suppression.

genomics↗

bioRxiv2019

Evidence for unfamiliar kin recognition in vampire bats

Kin discrimination allows organisms to preferentially cooperate with kin, reduce kin competition, and avoid inbreeding. In vertebrates, kin discrimination often occurs through prior association. There is less evidence for recognition of unfamiliar kin. Here, we present the first evidence of unfamiliar kin recognition in bats. We captured female vampire bats (Desmodus rotundus) from a single roost, allowed them to breed in captivity for 22 months, then released 17 wild-caught females and six captive-born daughters back into the same wild roost. We then used custom-built proximity sensors to track the free-ranging social encounters among the previously captive bats and 27 tagged control bats from the same roost. Using microsatellite-based relatedness estimates, we found that previously captive bats preferentially associated with related control bats, and that captive-born bats preferentially associated with unfamiliar kin among control bats. Closer analyses showed that these unfamiliar-kin-biased associations were not caused by mothers or other familiar close kin, because the kinship bias was evident even when those bats were not nearby. This striking evidence for unfamiliar kin recognition in vampire bats warrants further investigation and provides new hypotheses for how cooperative relationships might be driven synergistically by both social experience and phenotypic similarity.

animal behavior and cognition↗

bioRxiv2019

Thinking small: next-generation sensor networks close the size gap in vertebrate biologging

Recent advances in animal tracking technology have ushered in a new era in biologging. However, the considerable size of many sophisticated biologging devices restricts their application to larger animals, while old-fashioned techniques often still represent the state-of-the-art for studying small vertebrates. In industrial applications, low-power wireless sensor networks fulfill requirements similar to those needed to monitor animal behavior at high resolution and at low tag weight. We developed a wireless biologging network (WBN), which enables simultaneous direct proximity sensing, high-resolution tracking, and long-range remote data download at tag weights of one to two grams. Deployments to study wild bats created social networks and flight trajectories of unprecedented quality. Our developments highlight the vast capabilities of WBNs and their potential to close an important gap in biologging: fully automated tracking and proximity sensing of small animals, even in closed habitats, at high spatial and temporal resolution.

animal behavior and cognition↗

bioRxiv2018

Physical linkage and mate preference generate linkage disequilibrium for behavioral isolation in two parapatric crickets

Behavioral isolation is a potent barrier to gene flow and a source of striking diversity in the animal kingdom. However, it remains unclear if the linkage disequilibrium (LD) between sex-specific traits required for behavioral isolation results mostly from physical linkage between signal and preference loci or from directional mate preferences. Here, we test this in the field crickets Gryllus rubens and G. texensis. These closely related species diverged with gene flow and have strongly diverged songs and preference functions for the mate calling song rhythm. We map quantitative trait loci for signal and preference traits (pQTL) as well as for gene expression associated with these traits (eQTL). We find strong, positive genetic covariance between song traits and between song and preference. Our results show that this is in part explained by incomplete physical linkage: although both linked pQTL and eQTL couple male and female traits, major effect loci for different traits were never on the same chromosome. We suggest that the finely-tuned, highly divergent preference functions are likely an additional source of LD between male and female traits in this system. Furthermore, pleiotropy of gene expression presents an underappreciated mechanism to link sexually dimorphic phenotypes.

evolutionary biology↗

bioRxiv2018

Proximity sensors reveal social information transfer in maternity colonies of Greater noctule bats

O_LIBats are a highly gregarious taxon suggesting that social information should be readily available for making decision. Social information transfer in maternity colonies might be a particularly efficient mechanism for naive pups to acquire information on resources from informed adults. However, such behaviour is difficult to study in the wild, in particular in elusive and small-bodied animals such as bats.\nC_LIO_LIThe goal of this study was to investigate the role of social information in acquiring access to two types of resources, which are crucial in the life of a juvenile bat: suitable roosting sites and fruitful feeding grounds. We hypothesized that fledging offspring will make use of social information by following informed members of the social groups to unknown roosts or foraging sites.\nC_LIO_LIIn the present study we applied for the first time the newly developed miniaturized proximity sensor system BATS, a fully automated system for documenting associations among individual bats both while roosting and while on the wing. We quantified associations among juveniles and other group member while switching roosts and during foraging.\nC_LIO_LIWe found clear evidence for information transfer while switching roosts, mainly among juveniles and their genetically identified mothers. Anecdotal observations suggest intentional guidance behaviour by mothers, indicated by repeated commuting flights among the pup and the target roost. Infrequent, short meetings with colony members other than the mother indicate local enhancement at foraging sites, but no intentional information transfer.\nC_LIO_LIOur study illustrates how advances in technology enable researchers to solve long-standing puzzles. Miniaturized proximity sensors facilitate the automated collection of continuous data sets and represent an ideal tool to gain novel insights into the sociobiology of elusive and small-bodied species.\nC_LI

animal behavior and cognition↗

bioRxiv2018

Reticulate Evolutionary History of a Western Palaearctic Bat Complex Explained by Multiple mtDNA Introgressions in Secondary Contacts

AimThere is increasing evidence showing that species within various taxonomic groups have reticulate evolutionary histories with several cases of introgression events. Investigating the phylogeography of species complexes can provide insight about the introgressions, when and where these hybridizations occurred. In this study, we investigate the biogeography of a widely distributed Western Palaearctic bat species complex, namely Myotis nattereri sensu lato. This complex exhibits high genetic diversity and in its western distribution range is composed of deeply diverged genetical lineages. However, little is known about the genetic structure of the eastern populations. We also infer the conservation and taxonomical implications of the identified genetic divergences.\n\nLocationWestern Palaearctic\n\nMethodsWe analyzed 175 specimens collected from 67 locations and sequenced one mitochondrial and four nuclear DNA markers, and combined these with the available Gen-Bank sequences. We used haplotype networks, PCA, t-SNE, and Bayesian clustering algorithms to investigate the population structure and Bayesian trees to infer the phylogenetic relationship of the lineages.\n\nMain conclusionsWe identified deeply divergent genetical lineages. In some cases, nuclear and mitochondrial markers were discordant, which we interpret are caused by hybridization between lineages. We identified three such introgression events. Our findings suggest that the M. nattereri complex has a reticulate evolutionary history with multiple cases of hybridizations between some of the identified lineages. We also suggest a revision in the taxonomy of this species group, with two possible new taxa: M. hoveli and M. tschuliensis.

evolutionary biology↗

bioRxiv2017

Demography and selection shape transcriptomic divergence in field crickets

Gene flow, demography, and selection can result in similar patterns of genomic variation and disentangling their effects is key to understanding speciation. Here, we assess transcriptomic variation to unravel the evolutionary history of Gryllus rubens and Gryllus texensis, cryptic field cricket species with highly divergent mating behavior. We infer their demographic history and screen their transcriptomes for footprints of selection in the context of the inferred demography. We find strong support for a long history of bidirectional gene flow, which ceased during the late Pleistocene, and a bottleneck in G. rubens consistent with a peripatric origin of this species. Importantly, the demographic history has likely strongly shaped patterns of neutral genetic differentiation (empirical FST distribution). Concordantly, FST based selection detection uncovers a large number of outliers, likely comprising many false positives, echoing recent theoretical insights. Alternative genetic signatures of positive selection, informed by the demographic history of the sibling species, highlighted a smaller set of loci; many of these are candidates for controlling variation in mating behavior. Our results underscore the importance of demography in shaping overall patterns of genetic divergence and highlight that examining both demography and selection facilitates a more complete understanding of genetic divergence during speciation.

evolutionary biology↗