Biology subjects

Green, E. A.

Publications and source records attributed to Green, E. A..

4 recordsLinked to original sources

bioRxiv2026

B cells dominate the heart immune infiltrate during chronic infectious cardiomyopathy

Recent advances in single-cell and spatially resolved multi-omics have revolutionised our understanding of the cellular and molecular niches governing cardiac homeostasis and acute injury. However, the immune-stromal networks sustaining long-term, chronic heart pathology remain poorly defined, largely due to a paucity of physiologically relevant experimental models. Here, through a side-by-side multi-omic comparison of Trypanosoma cruzi-infected mouse models displaying contrasting degrees of chronic myocardial pathology and fibrosis, we define the long-term cellular landscape of the inflamed fibrotic heart. We reveal that class-switched, antibody-secreting plasma B cells represent the predominant immune subset infiltrating the fibrotic myocardium. CellChat intercellular communication modelling identifies plasma cell-fibroblast crosstalk as the strongest immune-stromal interaction in the fibrosis-prone heart, driven by predicted matrix anchoring (CD44-collagen/laminin) and molecular survival axes (App-Cd74, C3-Cr2). Supporting these computational predictions, immunofluorescence and spatial profiling confirm close proximity between plasma B cells and fibroblasts, alongside a striking accumulation of B cells embedded within extracellular matrix-rich cardiac scars. This localised B cell response maintains prominent pools of parasite-reactive and heart-autoreactive antibody-secreting cells despite a lack of detectable parasite signal in their immediate micro-vicinity. Together, these findings identify a matrix-associated plasma B cell-fibroblast niche as a central driver of chronic cardiac remodelling, revealing how persistent tissue scarring can become decoupled from direct local pathogen presence.

immunology↗

bioRxiv2024

Isolation and characterization of mollicute symbionts from a fungus-growing ant reveals genome reduction and host specialization

Two mollicute species belonging to the Mesoplasma and Spiroplasma genera have been detected in several species of fungus-growing ants using molecular methods. However, their ecological roles remain largely only inferred from metagenomic data. To better understand their diversity and specialization, we cultured both of these Mesoplasma and Spiroplasma symbionts from the fungus-growing ant Trachymyrmex septentrionalis, providing the first isolated mollicutes from any fungus-growing ant species. The genomes of our isolates and related metagenome-assembled genomes (MAGs) from T. septentrionalis fungus gardens comprise two unique phylogenetic lineages compared to previously described Mesoplasma and Spiroplasma species, and from related MAGs previously sequenced from the leaf-cutting ant Acromyrmex echinatior. This suggests that the T. septentrionalis symbionts comprise undescribed species with distinct host specificities. Mesoplasma genomes and MAGs also demonstrate regional specificity with their T. septentrionalis ant hosts. Both Mesoplasma and Spiroplasma strains from T. septentrionalis can catabolize glucose and fructose; both sugars are common in the ants diet. Similarly, both these Mesoplasma and Spiroplasma can catabolize arginine but only Mesoplasma can catabolize N-acetylglucosamine, which could both produce ammonia for the ants or fungus garden. Based on our genomic and phenotypic analyses, we describe these T. septentrionalis symbionts as Mesoplasma whartonense sp. nov. and Spiroplasma attinicola sp. nov., providing insight into their genomic and phenotypic diversity, and cultures to facilitate future studies of these common but poorly understood members of the fungus-growing ant symbiosis.

microbiology↗

bioRxiv2021

Trachymyrmex septentrionalis ant microbiome assembly is unique to individual colonies and castes.

Within social insect colonies, microbiomes often differ between castes due to their different functional roles, and between colony locations. Trachymyrmex septentrionalis fungus-growing ants form colonies throughout the eastern USA and Northern Mexico that include workers, female and male alates (unmated reproductive castes), larvae, and pupae. How T. septentrionalis microbiomes vary across this geographic range and between castes is unknown. Our sampling of individual ants from colonies across the Eastern USA revealed a conserved T. septentrionalis worker ant microbiome, and that worker ant microbiomes are more conserved within colonies than between them. A deeper sampling of individual ants from two colonies that included all available castes (pupae, larvae, workers, female and male alates), from both before and after adaptation to controlled laboratory conditions, revealed that ant microbiomes from each colony, caste, and rearing condition were typically conserved within but not between each sampling category. Tenericute bacterial symbionts were especially abundant in these ant microbiomes and varied widely in abundance between sampling categories. This study demonstrates how individual insect colonies primarily drive the composition of their microbiomes, and that these microbiomes are further modified by developmental differences between insect castes and the different environmental conditions experienced by each colony. IMPORTANCEThis study investigates microbiome assembly in the fungus-growing ant Trachymyrmex septentrionalis, showing how colony, caste, and lab adaptation influences the microbiome and revealing unique patterns of Mollicute symbiont abundance. We find that ant microbiomes differ strongly between colonies but less so within colonies. Microbiomes of different castes and following lab adaptation also differ in a colony-specific manner. This study advances understanding of the nature of individuality in social insect microbiomes, and cautions against the common practice of only sampling a limited number of populations to understand microbiome diversity and function.

microbiology↗

bioRxiv2020

North American fireflies host low bacterial diversity

Although there are numerous studies of firefly mating flashes, lantern bioluminescence, and anti-predation lucibufagin metabolites, almost nothing is known about their microbiome. We therefore used 16S rRNA community amplicon sequencing to characterize the gut and body microbiomes of four North American firefly taxa: Ellychnia corrusca, the Photuris versicolor species complex, Pyractomena borealis, and Pyropyga decipiens. These firefly microbiomes all have very low species diversity, often dominated by a single species, and each firefly type has a characteristic microbiome. Although the microbiomes of male and female fireflies did not differ from each other, Ph. versicolor gut and body microbiomes did, with their gut microbiomes being enriched in Pseudomonas and Acinetobacter. Ellychnia corrusca egg and adult microbiomes were unique except for a single egg microbiome that shared a community type with E. corrusca adults, which could suggest microbial transmission from mother to offspring. Mollicutes that had been previously isolated from fireflies were common in our firefly microbiomes. These results set the stage for further research concerning the function and transmission of these bacterial symbionts.

microbiology↗