ORCID Profile
0000-0003-4729-6390
Current Organisations
University of Adelaide
,
German Center for Integrative Biodiversity Research
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Publisher: Elsevier BV
Date: 10-2023
Publisher: Wiley
Date: 18-05-2022
DOI: 10.1111/EVO.14498
Abstract: Paternal age and past mating effort by males are often confounded, which can affect our understanding of a father's age effects. To our knowledge, only a few studies have standardized mating history when testing for effects of paternal age, and none has simultaneously disentangled how paternal age and mating history might jointly influence offspring traits. Here, we experimentally manipulated male mating history to tease apart its effects from those of paternal age on female fertility and offspring traits in the eastern mosquitofish (Gambusia holbrooki). Male age did not affect female fertility. However, males with greater past mating effort produced significantly larger broods. Paternal age and mating history interacted to affect sons' body size: sons sired by old-virgin males were larger than those sired by old-mated males, but this was not the case for younger fathers. Intriguingly, however, sons sired by old-virgin males tended to produce fewer sperms than those sired by old-mated males, indicating a potential trade-off in beneficial paternal effects. Finally, neither paternal age nor mating history affected daughter's fitness. Our results highlight that variation in offspring traits attributed to paternal age effect could partly arise due to a father's mating history, and not simply to his chronological age.
Publisher: Springer Science and Business Media LLC
Date: 05-06-2017
DOI: 10.1038/NCOMMS15632
Abstract: Interleukin 17-producing γδ T (γδT17) cells have unconventional trafficking characteristics, residing in mucocutaneous tissues but also homing into inflamed tissues via circulation. Despite being fundamental to γδT17-driven early protective immunity and exacerbation of autoimmunity and cancer, migratory cues controlling γδT17 cell positioning in barrier tissues and recruitment to inflammatory sites are still unclear. Here we show that γδT17 cells constitutively express chemokine receptors CCR6 and CCR2. While CCR6 recruits resting γδT17 cells to the dermis, CCR2 drives rapid γδT17 cell recruitment to inflamed tissues during autoimmunity, cancer and infection. Downregulation of CCR6 by IRF4 and BATF upon γδT17 activation is required for optimal recruitment of γδT17 cells to inflamed tissue by preventing their sequestration into uninflamed dermis. These findings establish a lymphocyte trafficking model whereby a hierarchy of homing signals is prioritized by dynamic receptor expression to drive both tissue surveillance and rapid recruitment of γδT17 cells to inflammatory lesions.
Publisher: Frontiers Media SA
Date: 22-06-2022
DOI: 10.3389/FIMMU.2022.873586
Abstract: Follicular T cells including T follicular helper (T FH ) and T follicular regulatory (T FR ) cells are essential in supporting and regulating the quality of antibody responses that develop in the germinal centre (GC). Follicular T cell migration during the propagation of antibody responses is largely attributed to the chemokine receptor CXCR5, however CXCR5 is reportedly redundant in migratory events prior to formation of the GC, and CXCR5-deficient T FH and T FR cells are still capable of localizing to GCs. Here we comprehensively assess chemokine receptor expression by follicular T cells during a model humoral immune response in the spleen. In addition to the known follicular T cell chemokine receptors Cxcr5 and Cxcr4 , we show that follicular T cells express high levels of Ccr6 , Ccr2 and Cxcr3 transcripts and we identify functional expression of CCR6 protein by both T FH and T FR cells. Notably, a greater proportion of T FR cells expressed CCR6 compared to T FH cells and gating on CCR6 + CXCR5 hi PD-1 hi T cells strongly enriched for T FR cells. Examination of Ccr6 -/- mice revealed that CCR6 is not essential for development of the GC response in the spleen, and mixed bone marrow chimera experiments found no evidence for an intrinsic requirement for CCR6 in T FR cell development or localisation during splenic humoral responses. These findings point towards multiple functionally redundant chemotactic signals regulating T cell localisation in the GC.
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.TREE.2022.09.004
Abstract: Anthropogenic pressures are driving insect declines across the world. Although protected areas (PAs) play a prominent role in safeguarding many vertebrate species from human-induced threats, insects are not widely considered when designing PA systems or building strategies for PA management. We review the effectiveness of PAs for insect conservation and find substantial taxonomic and geographic gaps in knowledge. Most research focuses on the representation of species, and few studies assess threats to insects or the role that effective PA management can play in insect conservation. We propose a four-step research agenda to help ensure that insects are central in efforts to expand the global PA network under the Post-2020 Global Bio ersity Framework.
Publisher: Springer Science and Business Media LLC
Date: 20-05-2019
DOI: 10.1038/S41564-019-0443-4
Abstract: The upper respiratory tract is continuously exposed to a vast array of potentially pathogenic viruses and bacteria. Influenza A virus (IAV) has particular synergism with the commensal bacterium Streptococcus pneumoniae in this niche, and co-infection exacerbates pathogenicity and causes significant mortality. However, it is not known whether this synergism is associated with a direct interaction between the two pathogens. We have previously reported that co-administration of a whole-inactivated IAV vaccine (γ-Flu) with a whole-inactivated pneumococcal vaccine (γ-PN) enhances pneumococcal-specific responses. In this study, we show that mucosal co-administration of γ-Flu and γ-PN similarly augments IAV-specific immunity, particularly tissue-resident memory cell responses in the lung. In addition, our in vitro analysis revealed that S. pneumoniae directly interacts with both γ-Flu and with live IAV, facilitating increased uptake by macrophages as well as increased infection of epithelial cells by IAV. These observations provide an additional explanation for the synergistic pathogenicity of IAV and S. pneumoniae, as well as heralding the prospect of exploiting the phenomenon to develop better vaccine strategies for both pathogens.
Publisher: Research Square Platform LLC
Date: 30-06-2022
DOI: 10.21203/RS.3.RS-1802901/V1
Abstract: Insects dominate the biosphere, driving ecosystem processes and functions that sustain humanity, yet insect populations are plummeting worldwide1. Massive conservation efforts will be needed to halt and reverse these declines2,3. Protected areas (PAs) could play a decisive role in safeguarding insect species from extinction4, but progress so far in achieving coverage of insect distributions by PAs remains undocumented. Here we show that 67,384 of 89,151 insect species assessed globally (76%) do not meet minimum target levels of PA coverage. Nearly 1,900 species from 225 families do not overlap with PAs at all. Species with low PA coverage predominantly occur in North America, Eastern Europe, South and Southeast Asia, and Australasia. The Post 2020 Global Bio ersity Framework5 provides a unique opportunity for nations to guide new PA designations that specifically take account of the needs of insects. Efforts to map important bio ersity areas now need to be upscaled to ensure nations capture and safeguard insect ersity.
Publisher: Springer Science and Business Media LLC
Date: 08-09-2023
Publisher: Frontiers Media SA
Date: 13-07-2021
DOI: 10.3389/FIMMU.2021.626199
Abstract: Crosstalk between T and B cells is crucial for generating high-affinity, class-switched antibody responses. The roles of CD4 + T cells in this process have been well-characterised. In contrast, regulation of antibody responses by CD8 + T cells is significantly less defined. CD8 + T cells are principally recognised for eliciting cytotoxic responses in peripheral tissues and forming protective memory. However, recent findings have identified a novel population of effector CD8 + T cells that co-opt a differentiation program characteristic of CD4 + T follicular helper (Tfh) cells, upregulate the chemokine receptor CXCR5 and localise to B cell follicles. While it has been shown that CXCR5 + CD8 + T cells mediate the removal of viral reservoirs in the context of follicular-trophic viral infections and maintain the response to chronic insults by virtue of progenitor/stem-like properties, it is not known if CXCR5 + CD8 + T cells arise during acute peripheral challenges in the absence of follicular infection and whether they influence B cell responses in vivo in these settings. Using the ovalbumin-specific T cell receptor transgenic (OT-I) system in an adoptive transfer-immunisation/infection model, this study demonstrates that CXCR5 + CD8 + T cells arise in response to protein immunisation and peripheral viral infection, displaying a follicular-homing phenotype, expression of cell surface molecules associated with Tfh cells and limited cytotoxic potential. Furthermore, studies assessing the B cell response in the presence of OT-I or Cxcr5 -/- OT-I cells revealed that CXCR5 + CD8 + T cells shape the antibody response to protein immunisation and peripheral viral infection, promoting class switching to IgG2c in responding B cells. Overall, the results highlight a novel contribution of CD8 + T cells to antibody responses, expanding the functionality of the adaptive immune system.
Publisher: Oxford University Press (OUP)
Date: 06-2023
Abstract: Citizen science programs are becoming increasingly popular among naturalists but remain heavily biased taxonomically and geographically. However, with the explosive popularity of social media and the near-ubiquitous availability of smartphones, many post wildlife photographs on social media. Here, we illustrate the potential of harvesting these data to enhance our bio ersity understanding using Bangladesh, a tropical bio erse country, as a case study. We compared bio ersity records extracted from Facebook with those from the Global Bio ersity Information Facility (GBIF), collating geospatial records for 1013 unique species, including 970 species from Facebook and 712 species from GBIF. Although most observation records were biased toward major cities, the Facebook records were more evenly spatially distributed. About 86% of the Threatened species records were from Facebook, whereas the GBIF records were almost entirely Of Least Concern species. To reduce the global bio ersity data shortfall, a key research priority now is the development of mechanisms for extracting and interpreting social media bio ersity data.
Location: Germany
No related grants have been discovered for Timona Tyllis.