Biology subjects

Moore, B. D.

Publications and source records attributed to Moore, B. D..

15 recordsLinked to original sources

bioRxiv2025

Forests and woodlands resistant to drought revealed in remotely sensed foliar moisture content using probabilistic models

Foliar moisture content (FMC) is of primary importance in many biological and ecological processes of forests and woodlands, including herbivory and fire dynamics. The role of FMC, which is the mass of moisture on a dry matter basis, in such processes is increasingly important due to changes in length and severity of climate extremes, like drought. Here we studied the sensitivity of forest and woodland FMC to climatic water balance, i.e. Standardised Precipitation and Evapotranspiration Index (SPEI), across five landscapes in temperate and sub-tropical south-eastern Australia. To do this we used copula-probabilistic modelling, including consideration of drought (i.e. SPEI) length. We used an FMC dataset over eight years of Sentinel-2 satellite reflectance (2015-2023), based on the inversion of a radiative transfer model at 20m resolution. We found the spatial variation of FMC within landscapes to be large and that the spatial variation in response to drought was very large, particularly within the more arid landscapes. The areas of lesser response to extreme drought are revealed to be drought resistant forests and woodlands that are potential climate refugia for animals, and natural breaks in the contiguity of fire fuels.

ecology↗

bioRxiv2025

Diel foliar moisture content recovery time occurs soon after midnight in Eucalyptus species of koala (Phascolarctos cinereus) habitats

Many herbivores are reliant on the foliar moisture content (FMC, the water mass as a percentage of the dry matter mass), of feed tree leaves, which may vary through the diel cycle. This includes koalas (Phascolarctos cinereus), who have heightened reliance on FMC during high temperatures. However, it is unknown how, and to what degree, FMC varies through the 24-hour period. In this experiment we measured live leaf FMC every three hours over the diel period by calibrating a near-infrared spectroscopy (NIRS) model from leaf-surface reflectance, for tree species associated with koala habitat. Coinciding with reflectance measurements, trees in a glasshouse were exposed to normal and extreme climatic conditions including heatwaves and a drought, while collecting concurrent climate variables and soil moisture content. Our analysis of FMC timeseries of glasshouse trees found the diel range of leaf FMC was 23 % dry weight (DW, i.e. 19 % fresh weight) on average, between a minimum and maximum diel range of 10 %DW and 46 %DW, as predicted by an accurate spectral regression model (r2=0.96, RMSE=9.29 %DW). Overall, FMC minima occurred at 13:30 and FMC had recovered to initial levels (7:30) by 1:30 the following morning, though near-recovery levels were reached earlier by 19:30. This result shows that during a single day and night koala tree species may vary the proportion of leaf moisture by about one fifth, on average, and the timing of canopy moisture recovery may discourage foraging in the evening on temporarily dry species, during hot conditions.

ecology↗

bioRxiv2025

Monitoring Forest Foliar Moisture Using Sentinel-2 Reflectance and Radiative Transfer Model Inversion

Foliar moisture content (FMC) of forests canopies is important for understanding biodiversity, including animal habitat quality for forest-dependent fauna and forest fire risk. In this study, we modelled spatiotemporal variation in FMC using optical remote sensing. We inverted the PROSPECT and GEOSAIL Radiative Transfer Models (RTM) on Sentinel-2 satellite reflectance data of 20 m ground resolution to retrieve FMC, and then predicted FMC at sub-continental scales using a random forest (RF) regression emulation of the RTM model. An RTM look-up-table, from earlier work, was filtered by ecological criteria from 24 sites sampled along precipitation and canopy cover gradients and was inverted by using the spectral angle, as a merit function. The RF emulator allowed efficient computation and presentation of an extensive and fine-scale forest FMC data cube of interest in animal, fire and plant ecology. Our RTM-based, predictions of forest and woodland FMC had a root mean square error (RMSE) of 19.9% of dry matter content and explained more than 60% of variance (r2 = 0.62). This represents an improvement over previous models using reflectance data of coarser spatial resolution, particularly in terms of explained variance (r2=0.17 and RMSE=32%). The emulator model achieved similar performance to the RTM with slightly larger error (RMSE = 21.77%) and smaller explained variance (r2 = 0.54). Overall, both models performed best in forests, and woodlands of moderate to high canopy density (> [~]0.75 LAI). This study demonstrates that FMC can be monitored at spatial resolutions that allow intra- or inter-landscape patterns to be resolved surpassing previous capabilities. Index TermsFoliar moisture content, FMC, remote sensing, radiative-transfer, forest, inversion, Sentinel-2, emulator, koala

ecology↗

bioRxiv2025

Plant silicon defence disrupts cryptic colouration in an insect herbivore by restricting carotenoid sequestration into the haemolymph

O_LICryptic colouration is a primary anti-predation strategy in herbivorous insects. Achieving crypsis often requires acquiring dietary carotenoids--tetraterpene pigments vital for plant colouration and photoprotection. Silicon (Si) accumulation in plants makes tissues tougher and less digestible for insects, but its effect on plant pigment levels remains unclear. It is also unknown whether feeding on silicified plants impairs insects ability to sequester carotenoids and achieve crypsis. C_LIO_LIUsing the model grass Brachypodium distachyon, we demonstrate that the cotton bollworm (Helicoverpa armigera) larvae exhibited stunted growth and reduced carotenoid sequestration, particularly lutein, into their hemolymph when feeding on Si- supplemented (+Si) plants. This reduction led to distinct body-colour morphs: larvae feeding on +Si plants developed brown colouration, contrasting sharply with the green leaves, whereas larvae feeding on Si-free (-Si) plants exhibited green cryptic colouration that blended seamlessly with the foliage. C_LIO_LIPlant leaves contained various carotenoids (neoxanthin, violaxanthin, {beta}-carotene and lutein) and chlorophylls (a and b), but larvae only sequestered {beta}-carotene and lutein into their haemolymph while excreting substantial amounts of pigments, regardless of plant Si status. Under insect-free conditions, +Si plants had lower carotenoid and chlorophyll contents than -Si plants. However, following insect herbivory, pigment levels in -Si and +Si plants equalised. Insect herbivory also increased Si accumulation in +Si plants. C_LIO_LIOur findings provide novel evidence that plant Si defences can disrupt cryptic colouration in insect herbivores by restricting carotenoid sequestration from host plant tissues. This disruption could increase insect visibility to predators, potentially elevating their risk of predation. C_LI

ecology↗

bioRxiv2023

Aβ Amyloid Scaffolds the Accumulation of Matrisome and Additional Proteins in Alzheimer's Disease

We report a highly significant correlation between human Alzheimers disease (AD) brain proteome changes and those in CRND8 APP695NL/F transgenic mice. Comparing protein changes observed in the CRND8 mice with co-expression networks derived from human Alzheimers disease (AD), reveals both conserved and divergent module changes. Many proteins in the most highly conserved module (M42, matrisome) accumulate in plaques, cerebrovascular amyloid (CAA), dystrophic neuronal processes, or a combination thereof. Overexpression of two M42 proteins, midkine (Mdk) and pleiotrophin (PTN), in CRND8 mice brains leads to increased accumulation of A{beta} in plaques and in blood vessels; further, recombinant MDK and PTN enhance A{beta} aggregation into amyloid structures. Multiple M42 proteins bind to fibrillar A{beta}42 and a non-human amyloid fibril in vitro. Supporting this binding data, MDK and PTN co-accumulate with transthyretin (TTR) amyloid in the heart. Notably, our findings establish that proteomic changes in modules observed in human AD brains define an A{beta} amyloid "responsome" that is well conserved from mouse models to humans. Further, distinct amyloid structures appear to serve as scaffolds, facilitating the co-accumulation of proteins with signaling functions, and this co-accumulation may contribute to downstream pathological sequalae. Overall, this contextualized understanding of proteomic changes and their interplay with amyloid deposition provides valuable insights into the complexity of AD pathogenesis and potential biomarkers and therapeutic targets.

neuroscience↗

bioRxiv2023

Silicon supplementation and jasmonate activation synergistically increase phenolic defences against a legume herbivore

O_LIThe accumulation of silicon (Si) is widely reported to have anti-herbivore defensive properties in grasses. There is emerging, but fragmentary, evidence that Si could play a similar role in legumes. C_LIO_LIHere, we sought to understand the effects of Si supplementation on anti-herbivore defensive properties in lucerne (Medicago sativa), especially in relation to other potential defences (i.e. phenolics) and the phytohormone that regulates anti-herbivore defences, jasmonic acid or jasmonate (JA), which is also linked to Si accumulation. C_LIO_LIWe determined how growth, root nodulation and chemistry (carbon, nitrogen and phenolic concentrations) of four genotypes of lucerne responded to Si supplementation, with and without the application of JA, and we used feeding assays to determine the subsequent effects on the feeding success of adult Sitona discoideus weevils. C_LIO_LISi supplementation increased plant mass and root nodulation of M. sativa by 61% and 227%, respectively, and reduced relative consumption (RC) and frass production by S. discoideus by 38% and 30%, respectively. Si supplementation had no effect on foliar nitrogen concentrations, most likely due to the dilution effects of increased plant growth and foliar carbon. Phenolic concentrations were negatively correlated with leaf RC; RC also decreased by 34% when JA was applied to plants. When Si was combined with JA application, phenolics were significantly enhanced, demonstrating the potential to stimulate multiple anti-herbivore properties in M. sativa. C_LIO_LISynthesis. The novel findings suggest that Si accumulation may play a more important role in legume resistance to herbivorous animals than previously thought. The ubiquity of soil Si and its emerging functional role in plant biology, including plant-animal interactions, suggest that these patterns could be common amongst legumes. C_LI

ecology↗

bioRxiv2023

Peptide ligands for the affinity purification of adeno-associated viruses from HEK 293 cell lysates

Adeno-associated viruses (AAVs) are the vector of choice for delivering gene therapies that can cure inherited and acquired diseases. Clinical research on various AAV serotypes significantly increased in recent years alongside regulatory approvals of AAV-based therapies. The current AAV purification platform hinges on the capture step, for which several affinity resins are commercially available. These adsorbents rely on protein ligands - typically camelid antibodies - that provide high binding capacity and selectivity, but suffer from low biochemical stability and high cost, and impose harsh elution conditions (pH < 3) that can harm the transduction activity of recovered AAVs. Addressing these challenges, this study introduces peptide ligands that selectively capture AAVs and release them under mild conditions (pH 6.0). The peptide sequences were identified by screening a focused library and modeled in silico against AAV serotypes 2 and 9 (AAV2 and AAV9) to select candidate ligands that target homologous sites at the interface of the VP1-VP2 and VP2-VP3 virion proteins with mild binding strength (KD [~] 10- 5-10-6 M). Selected peptides were conjugated to Toyopearl resin and evaluated via binding studies against AAV2 and AAV9, demonstrating the ability to target both serotypes with values of dynamic binding capacity (DBC10% > 1013 vp per mL of resin) and product yields ([~]50-80%) on par with commercial adsorbents. The peptide-based adsorbents were finally utilized to purify AAV2 from a HEK 293 cell lysate, affording high recovery (50-80%), 80-to-400-fold reduction of host cell proteins (HCPs), and high transduction activity (up to 80%) of the purified viruses.

bioengineering↗

bioRxiv2023

A new genetic method for diet determination from faeces that provides species level resolution in the koala

An animals diet is a crucial trait that defines their realised ecological niche, especially for dietary specialists such as the koala (Phascolarctos cinereus), a threatened arboreal marsupial folivore. Unfortunately, the current methods used to characterise koala diet are labour intensive, biased and/or unreliable. Further, in this study we show that four barcoding genes (ITS, ETS, CCR and matK) are unable to resolve potential koala food trees to species. Therefore, we developed and tested a novel SNP-based method for the analysis of koala diet from faeces using the DArTseq platform. This method returned a large number of species-specific SNPs for candidate koala food tree species. Due to low within-species variation, few individuals of each tree species are needed to capture the majority of DArTseq SNP diversity. Nonetheless, we suggest sampling multiple trees to reduce the impact of high allele dropout rates in the DArTseq data. After identifying species-specific SNPs from candidate food tree species from two study sites with different assemblages of eucalypts we were able to detect those SNPs in koala faecal DNA using DArTag, a targeted genotyping assay. This enabled us to semi-quantitatively characterise the koalas diets. The food tree species identified were in broad agreement with previously known koala food tree species but also revealed additional species that may contribute to koala diet. This approach provides an important new tool for use in koala ecology and conservation and may prove useful in diet determination for other species where high taxonomic resolution is crucial and dietary DNA is scarce.

microbiology↗

bioRxiv2021

Geographic patterns of koala retrovirus genetic diversity, endogenization and subtype distributions

Koala retrovirus subtype A is the youngest endogenized retrovirus, providing a unique system to elucidate retroviral-host co-evolution. We characterised KoRV geography using faecal DNA from 192 samples across 20 populations throughout the koalas range. We reveal an abrupt change in KoRV genetics and incidence at the Victoria/NSW state border. In northern koalas, pol gene copies were ubiquitously present at greater than 5 per-cell, consistent with endogenous KoRV. In southern koalas, pol copies were detected in only 25.8% of koalas and always at copy numbers less than one, while the env gene was detected in all animals and in a majority at copy numbers of greater than one per-cell. These results suggest that southern koalas carry partial endogenous KoRV-like sequences. Deep sequencing of the env hypervariable region revealed three putatively endogenous KoRV-A sequences in northern koalas and a single, distinct sequence present in all southern koalas. Among northern populations, env sequence diversity decreased with distance from the equator, suggesting infectious KoRV-A invaded the koala genome in northern Australia and then spread south. The previously described exogenous KoRV subtypes (B-K), two novel subtypes (L and M), and intermediate or hybrid subtypes were detected in all northern koala populations but strikingly absent from all southern animals tested. Apart from KoRV-D, these exogenous subtypes were generally locally prevalent but geographically restricted, producing KoRV genetic differentiation among northern populations. This suggests that sporadic evolution and local transmission of the exogenous subtypes has occurred within northern Australia, but this has not extended into animals within southern Australia. Author SummaryRetrovirus infection is generally synonymous with disease; however, retroviruses can also become endogenous (incorporated into the germline) and thereby directly contribute to the genetic makeup of a species. This has occurred in all vertebrates, yet little is known about the endogenization process. As the youngest virus known to be endogenized, koala retrovirus (KoRV) offers a unique opportunity to study these early stages of co-evolution. This study reveals a comprehensive picture of KoRV biogeography that informs our understanding of how host population history, host suppression and transmission dynamics can influence retroviral evolution. KoRV is also associated with chlamydiosis and neoplasia in the vulnerable koala. Our improved understanding of how KoRV variants are distributed should guide conservation management to help limit disease.

microbiology↗

bioRxiv2021

Plant structural and nutritional responses to drought differ among common pasture species

In the face of a changing climate, research indicates that more frequent and severe drought conditions are critical problems that will constrain production of high-quality forage and influence the performance of grazing animals in the future. In addition, the duration of drought and potential trade-offs between plant morphology and nutritional composition may influence plant drought adaptation strategies across pasture species, and the consequences for forage quality are not well understood. Here we present the results of a study investigating the effects of drought on biomass productivity, dead material, leaf:stem biomass allocation and nutritional composition (whole-plant and tissue-specific) across nine diverse pasture species. For this, we conducted a field experiment exposing species to a 6-month period of simulated severe drought (60% rainfall reduction during winter and spring) and samples were collected at multiple harvests. We found that drought had different, harvest-specific effects on plant biomass structure and nutritional composition among pasture species. The severity of drought impacts on productivity, but not on nutritional quality, increased with drought duration. In general, drought strongly reduced productivity, increased the percentage of dead material and had mixed effects (increases, decreases and no effect) on leaf:stem ratio and concentrations of crude protein, non-structural carbohydrates, neutral detergent fibre and lignin. Changes in plant-level nutritional quality were driven by simultaneous changes in both leaf and stem tissues for most, but not all, species. Our findings may be especially helpful for selection of adapted species/cultivars that could minimize potential drought risks on forage, thereby optimising pasture performance under future drought scenarios.

plant biology↗

bioRxiv2021

Near-infrared spectroscopy calibration strategies to predict multiple nutritional parameters of pasture species from different functional groups

Near-infrared reflectance spectroscopy (NIRS) has been used by the agricultural industry as a high-precision technique to quantify nutritional chemistry in plants both rapidly and inexpensively. The aim of this study was to evaluate the performance of NIRS calibrations in predicting the nutritional composition of ten pasture species that underpin livestock industries in many countries. These species comprised a range of functional diversity (C3 legumes; C3/C4 grasses; annuals/perennials) and origins (tropical/temperate; introduced/native) that grew under varied environmental conditions (control and experimentally induced warming and drought) over a period of more than 2 years (n = 2,622). A maximal calibration set including 391 samples was used to develop and evaluate calibrations for all ten pasture species (global calibrations), as well as for subsets comprised of the plant functional groups. We found that the global calibrations were appropriate to predict the six key nutritional quality parameters studied for our pasture species, with the highest accuracy found for ash (ASH), crude protein (CP), neutral detergent fibre and acid detergent fibre (ADF), and the lowest for ether extract (EE) and acid detergent lignin parameters. The plant functional group calibrations for C3 grasses performed better than the global calibrations for ASH, CP, ADF and EE parameters, whereas for C3 legumes and C4 grasses the functional group calibrations performed less well than the global calibrations for all nutritional parameters of these groups. Additionally, our calibrations were able to capture the range of variation in forage quality caused by future climate scenarios of warming and severe drought.

plant biology↗

bioRxiv2021

Microglia show differential transcriptomic response to Aβ peptide aggregates ex vivo and in vivo

Aggregation and accumulation of amyloid-{beta} (A{beta}) is a defining feature of Alzheimers disease (AD) pathology. To study microglial responses to A{beta}, we applied exogenous A{beta} peptide, in either oligomeric or fibrillar conformation, to primary mouse microglial cultures and evaluated system level transcriptional changes and then compared these to transcriptomic changes in the brains of CRND8 APP mice. We find that primary microglial cultures have rapid and massive transcriptional change to in response to A{beta}. Transcriptomic responses to oligomeric or fibrillar A{beta} in primary microglia, though partially overlapping, are distinct and are not recapitulated in vivo where A{beta} progressively accumulates. Furthermore, though classic immune mediators show massive transcriptional changes in the primary microglial cultures, these changes are not observed in the mouse model. Together, these data extend previous studies which demonstrate that microglia responses ex vivo are poor proxies for in vivo responses. Finally, these data demonstrate the potential utility of using microglia as biosensors of different aggregate conformation, as the transcriptional responses to oligomeric and fibrillar A{beta} can be distinguished.

neuroscience↗

bioRxiv2021

Drought is a stronger driver of plant morphology and nutritional composition than warming in two common pasture species

Under warmer and drier future conditions, global livestock and dairy production are threatened by impacts on the productivity and nutritional quality of pastures. However, morphological and nutritional adjustments within plants in response to warming and drought vary among species and less is known how these relate to production and forage quality. To investigate this, we grew two common pasture species, tall fescue (Festuca arundinacea: grass) and lucerne (Medicago sativa: legume), in a climate-controlled facility, under different temperatures (ambient and elevated) and watering regimes (well-watered and droughted). We found that drought had a strong negative impact on biomass production, morphology and nutritional quality while warming only significantly affected both species when response metrics were considered in concert, although to a lesser degree than the drought. Furthermore, interactions between warming and drought were only seen for lucerne, with the greatest reduction in biomass and most dead material and dry matter content. In tall fescue, drought had bigger impacts on nutritional composition than morphological traits, while in lucerne, drought affected all morphological traits and most nutritional parameters. These findings suggest that in future climate scenarios, drought may be a stronger driver of changes in the morphology and nutritional composition of pasture grasses and legumes, compared to modest levels of warming.

plant biology↗

bioRxiv2020

Pastures and Climate Extremes: Impacts of warming and drought on the productivity and resilience of key pasture species in a field experiment

Shifts in the timing, intensity and/or frequency of climate extremes, such as severe drought and heatwaves, can generate sustained shifts in ecosystem function with important ecological and economic impacts for rangelands and managed pastures. The Pastures and Climate Extremes experiment (PACE) in Southeast Australia was designed to investigate the impacts of a severe winter/spring drought (60% rainfall reduction) and, for a subset of species, a factorial combination of drought and elevated temperature (ambient +3 {degrees}C) on pasture productivity. The experiment included nine common pasture and Australian rangeland species from three plant functional groups (C3 grasses, C4 grasses and legumes) planted in monoculture. Winter/spring drought resulted in productivity declines of 45% on average and up to 74% for the most affected species (Digitaria eriantha) during the 6-month treatment period, with eight of the nine species exhibiting significant yield reductions. Despite considerable variation in species sensitivity to drought, C4 grasses were more strongly affected by this treatment than C3 grasses or legumes. Warming also had negative effects on cool-season productivity, associated at least partially with exceedance of optimum growth temperatures in spring and indirect effects on soil water content. The combination of winter/spring drought and year-round warming resulted in the greatest yield reductions. We identified responses that were either additive such that there was only as significant warming effect under drought (Festuca), or less-than-additive, where there was no drought effect under warming (Medicago), compared to ambient plots. Results from this study highlight the sensitivity of diverse pasture species to increases in winter and spring drought severity similar to those predicted for this region, and that anticipated benefits of cool-season warming are unlikely to be realised. Overall, the substantial negative impacts on productivity suggest that future, warmer, drier climates will result in shortfalls in cool-season forage availability, with profound implications for the livestock industry and natural grazer communities.

ecology↗

bioRxiv2019

The fate of carbon in a mature forest under carbon dioxide enrichment

Atmospheric carbon dioxide enrichment (eCO2) can enhance plant carbon uptake and growth1,2,3,4,5, thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO2 concentration6. While evidence gathered from young aggrading forests has generally indicated a strong CO2 fertilization effect on biomass growth3,4,5, it is unclear whether mature forests respond to eCO2 in a similar way. In mature trees and forest stands7,8,9,10, photosynthetic uptake has been found to increase under eCO2 without any apparent accompanying growth response, leaving an open question about the fate of additional carbon fixed under eCO24, 5, 7,8,9,10,11. Here, using data from the first ecosystem-scale Free-Air CO2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responds to four years of eCO2 exposure. We show that, although the eCO2 treatment of ambient +150 ppm (+38%) induced a 12% (+247 gCm-2yr-1) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone contributing [~]50% of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO2, and challenge the efficacy of climate mitigation strategies that rely on CO2 fertilization as a driver of increased carbon sinks in standing forests and afforestation projects.

ecology↗