Biology subjects

Abbott, C. A.

Publications and source records attributed to Abbott, C. A..

4 recordsLinked to original sources

bioRxiv2024

Friend, food, or foe: sea anemones discharge fewer nematocysts at familiar anemonefish after delayed mucus adaptation.

1.For decades, it has been hypothesized that anemonefishes are able to live within the stinging tentacles of host sea anemone species because the chemical composition of their mucus layer inhibits or lacks the trigger for firing host nematocysts. However, there is very little molecular evidence for this, beyond suggestions that glycans in the mucus could be key. In this study we assessed these hypotheses by testing Bubble-tip anemone (Entacmaea quadricolor) nematocysts in response to three different mucus sources, before and after anemonefish association. We also profiled the corresponding mucus lipid and glycan composition of anemonefish. Host sea anemones significantly reduced nematocyst firing at acclimated anemonefish mucus compared to mucus from unacclimated individuals. Changes in anemonefish mucus glycan composition became distinguishable three weeks after introduction relative to an anemonefish that was not living in association of a host sea anemone. The glycan composition reverted back to a pre-acclimated composition when profiled 24 hours after anemonefish removal from a host sea anemone. Triggering fewer nematocysts through glycan profile alterations may be an important adaptation that has enabled anemonefish to live long-term in a sea anemone host. However, the delay in mucus response indicates it is not the initial mechanism used by anemonefish to enter a host sea anemone without being stung.

ecology↗

bioRxiv2024

Urban greenspace aerobiomes are shaped by soil conditions and land cover type

Growing evidence suggests that exposure to microbial biodiversity is important for human immunoregulation and health. Urban greenspaces harbour airborne bacterial communities (aerobiomes) with the potential to transfer beneficial bacteria to humans. However, limited studies have examined the ecological influences of soil, vegetation, and rainfall on aerobiomes in urban greenspaces. Here, we utilised 16S rRNA amplicon sequence data to analyse the effects of land cover, soil abiotic characteristics, surrounding vegetation diversity, and rainfall on aerobiome diversity and composition from 33 urban greenspace sites in Adelaide, South Australia. We sampled air and soil from two urban greenspace land cover types: highly-managed sports fields (n = 11) and minimally-managed nature parks (n = 22). Sports field aerobiomes had a distinct aerobiome community composition and higher alpha diversity than nature parks. Aerobiome alpha diversity was shaped more by soil abiotic characteristics, particularly soil pH and iron levels, than woody plant species diversity. Rainfall prior to sampling also had strong effects on the aerobiome community composition and associated with decreased alpha diversity. These findings point toward soil iron and pH management as pathways to increase aerobiome bacterial diversity. Our study shows that, with additional research, there is potential for greenspace managers and urban planners to target specific soil abiotic characteristics in urban greenspaces to improve microbiome-mediated urban health.

ecology↗

bioRxiv2022

Novel populations of Tr1 cells contribute to the resolution of acute influenza A virus infection.

Type I regulatory (Tr1) cells contribute to immune suppression in the context of chronic infection, autoimmunity, and transplant tolerance. However, their physiological relevance in the resolution of acute respiratory infection is not understood. Here, we identify Tr1 cells accumulating in the lung parenchyma during resolution of the response to sublethal influenza A virus infection in mice. Tr1 cells were dependent on IL-27R and in their absence recovery from IAV-induced weight loss is impaired. Notably, these Tr1 cells did not necessarily co-express the typical Tr1 markers LAG-3 and CD49b, with four distinct populations of Tr1 cells apparent in the lungs. Each population was suppressive and were differentially dependent on IL-10 to mediate suppression. Transcriptional analysis revealed a core Tr1 gene signature in each population and distinct expression profiles indicative of different states of activation and differentiation. Finally, sort-transfer experiments indicated non-linear plasticity between these subsets of Tr1 cells. Together, these data support Tr1 cells contributing to the resolution of acute inflammation and define novel Tr1 cell phenotypes in acute infection.

immunology↗

bioRxiv2022

Biogeography of human-health associated butyrate-producing bacteria

AimButyrate-producing bacteria are found in many outdoor ecosystems and host organisms, including humans, and are vital to ecosystem functionality and human health. These bacteria ferment organic matter, producing the short-chain fatty acid butyrate. However, few (if any) studies have examined the macroecological influences on their large-scale biogeographical distribution. Here we aimed to characterise their global biogeography together with key explanatory climatic, geographic, and physicochemical variables. LocationGlobal, and the Australian continent Time period2005-2020 Major taxa studiedButyrate-producing bacteria MethodsWe developed new normalised butyrate production capacity (BPC) indices derived from global metagenomic (n=13,078) and Australia-wide soil 16S rRNA (n=1,331) data, using Geographic Information System (GIS) and modelling techniques to detail their ecological and biogeographical associations. ResultsThe highest BPC scores were found in anoxic and fermentative environments, including the human and non-human animal gut, and in some plant-soil systems. Within plant-soil systems, roots and rhizospheres had the highest BPC scores. Among soil samples, geographic and climatic variables had the strongest overall influence on BPC scores, with human influence also making key contributions. Higher BPC scores were in soils from seasonally productive sandy rangelands, temperate rural residential areas, and sites with moderate-to-high soil iron concentrations. Main conclusionsAbundances of butyrate-producing bacteria in outdoor soils follow complex ecological patterns influenced by geography, climate, soil chemistry, and hydrological fluctuations. Human population density and soil iron also play substantial roles, and their effects are dependent on a combination of ecological variables. These new biogeographical insights further our understanding of the global ecology patterns of butyrate-producing bacteria, with implications for emerging microbially-focussed ecological and human health policies.

ecology↗