Biology subjects

Papp, T.

Publications and source records attributed to Papp, T..

7 recordsLinked to original sources

bioRxiv2026

Interaction Patterns of Mucormycotina Fungi with Professional Phagocytes and Amoebae: A Comparative Phylogenetic and Geographic Survey on Clinical and Environmental Species

Mucormycosis is among the most lethal fungal infections in clinical medicine, with crude mortality rates between 50 and 90% that have improved little over decades of antifungal development. Alveolar macrophages constitute the primary cellular defense against inhaled Mucorales spores, yet quantitative comparative data on phagocytic outcomes across the taxonomic breadth of this fungal order are absent from the literature. We co-incubated 62 Mucorales strains drawn from nine phylogenetic groups and 12 countries with MH-S murine alveolar macrophages and with Dictyostelium discoideum amoeba, at multiplicities of infection (MOI) of 1 and 5 and at incubation times of 1.5 and 3 hours. Automated phagocytic index quantification was combined with spore morphometric measurements and geographic metadata. Macrophage phagocytic indices differed highly significantly among the nine phylogenetic groups across all experimental conditions (Kruskal-Wallis H = 394-780; p = 10^-163 to 10^-74). Group 1 (Absidia and Cunninghamella species) showed the lowest phagocytic index; Groups 5 (Rhizopus arrhizus) and 6 (Gilbertella persicaria and Mycotypha species) showed the highest. Larger spore area correlated negatively with macrophage phagocytic index. In the central comparative finding, Spearman rank correlations between macrophage and D. discoideum phagocytic indices were near zero across all four conditions (r = -0.07 to +0.11; all p > 0.8), demonstrating that protozoan phagocytosis does not predict the mammalian macrophage phagocytic hierarchy. Kinetic analysis further revealed, for the first time in any Mucorales or Mucormycotina species, evidence of vomocytosis in MH-S macrophages challenged with Group 8 (Mucor clade II) spores at MOI 1, and in D. discoideum across four groups at MOI 5 after 3 hours. These findings establish a quantitative, phylogenetically resolved framework for Mucorales innate immune recognition, demonstrate that the evolutionary training ground hypothesis does not hold at the order level for Mucorales, and identify vomocytosis as a previously unrecognised immune evasion mechanism in Mucormycotina.

microbiology↗

bioRxiv2025

Behavioral anapyrexia as a response to virus infection in a poikilothermic vertebrate

Behavioral plasticity may contribute to the ability of wild animals to survive disease outbreaks. In absence of endogen heat control, poikilothermic animals adjust their body temperature behaviorally. While many studies reported behavioral fever, its opposite, behavioral anapyrexia - when infected animals lower their body temperature by using cool microenvironments - remains poorly documented. Here, we report the first evidence of behavioral anapyrexia in a poikilothermic vertebrate as a response to pathogenic infection. We investigated thermoregulatory responses in tadpoles of the agile frog Rana dalmatina, a cool-adapted amphibian, following experimental infection with a warm-adapted ranavirus. Tadpoles were placed either in thermal gradients or homogeneously cool environments for five days post-exposure. In thermal gradients, all tadpoles reduced their preferred temperatures over time, but this decrease was steeper in infected tadpoles, and individuals with higher infection intensities preferred cooler temperatures. Infected tadpoles became increasingly precise in thermoregulation over time, while a similar trend was not detectable in non-infected tadpoles. Infection prevalence was similar between the two thermal environments, yet infection intensities were significantly higher in the thermal gradient. These results suggest fine-tuned thermoregulation by infected tadpoles to balance out the benefits of behavioral anapyrexia for fighting a warm-adapted pathogen versus the immune-suppressive and developmental costs of low temperatures.

ecology↗

bioRxiv2024

Juvenile agile frogs spatially avoid ranavirus-infected conspecifics, but do not show generalized social distancing or self-isolation

Exposure to contagious pathogens can result in behavioural changes, which can alter the spread of infectious diseases. Healthy individuals can express generalized social distancing or actively avoid the sources of infection, while infected individuals can show passive or active self-isolation. Amphibians are globally threatened by serious contagious diseases, yet their behavioural responses to infections are very scarcely known. We studied behavioural changes in agile frog (Rana dalmatina) juveniles upon exposure to a Ranavirus (Rv). We performed classic choice tests in chambers containing a conspecific infected with Rv in one end compartment and a non-infected conspecific in the other end, with an Rv-infected or non-infected focal individual in the central compartment. We found that both non-infected and Rv- infected focal individuals spatially avoided infected conspecifics, while there were no signs of generalized social distancing, nor self-isolation. Spatial avoidance of infected conspecifics may effectively hinder disease transmission. On the other hand, the absence of self-isolation by infected individuals may facilitate it. Our finding that infected individuals spent more time near the non-infected than infected conspecifics suggests that the strong behavioural drive to avoid infected conspecifics may not be silenced by infection, possibly to prevent secondary infections. The observation that infected focal individuals did not spend more time near conspecifics than non-infected focals renders it unlikely that the pathogen manipulated host behaviour to aid disease spread. More research is urgently needed to understand under what circumstances behavioural responses can help amphibians cope with infections, and how that affects disease dynamics in natural populations. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=68 SRC="FIGDIR/small/588850v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@59b5a9org.highwire.dtl.DTLVardef@1a59896org.highwire.dtl.DTLVardef@c4bc64org.highwire.dtl.DTLVardef@2c76c3_HPS_FORMAT_FIGEXP M_FIG C_FIG

animal behavior and cognition↗

bioRxiv2022

mRNA-mediated induced regeneration of the corneal endothelium

Loss of vision due to corneal endothelial dysfunction affects millions worldwide. The development of new treatments is hampered by the incomplete knowledge of the regenerative capacity of corneal endothelial cells in vivo. Herein, we developed a mouse model to directly monitor corneal endothelial regeneration in real time, and at the single cell level, by two-photon microscopy. We show that the mouse corneal endothelium recapitulates the main features of human endothelial physiology, including complete cellular quiescence and a decline in cell density with aging. Critically, we demonstrate the endogenous regenerative potential of the tissue by capturing the proliferation of corneal endothelial cells during repair of large injuries. By single cell lineage tracing analysis, we provide evidence that corneal endothelial cells are equipotent in their ability to activate the cell cycle and contribute to tissue regeneration. Based on these findings we developed a feasible therapeutic approach to stimulate the regeneration of the corneal endothelium, using modified mRNA technology. To reprogram corneal endothelial cells in vivo and unlock their ability to escape quiescence, we combined five modified mRNAs encoding for proteins involved in cell cycle activation. Injection of the encapsulated mRNAs directly into the eye of older mice induced transient proliferation of corneal endothelial cells that led to an increase in endothelial cell density, effectively reversing the effect of aging. This therapeutic strategy offers a compelling paradigm for treating ocular disease and modulating tissue regeneration in organs with limited endogenous ability.

cell biology↗

bioRxiv2022

CotH genes are necessary for normal spore formation and virulence in Mucor lusitanicus

Mucormycosis is an invasive fungal infection caused by certain members of the fungal order of Mucorales. The species most frequently identified as the etiological agents of mucormycosis belong to the genera Rhizopus, Lichtheimia and Mucor. The frequency of systemic mucormycosis has been increasing, mainly because of the elevating numbers of susceptible patients. Furthermore, Mucorales display intrinsic resistance to the majority of routinely used antifungal agents (e.g., echinocandins and short-tailed azoles), which limits the number of possible therapeutic options. All the above-mentioned issues urge the improvement of molecular identification methods and the discovery of new antifungal targets and strategies. Spore coat proteins (CotH) constitute a kinase family present in many pathogenic bacteria and fungi and participate in the spore formation in these organisms. Moreover, some of them can act as virulence factors being receptors of the human GRP78 protein during Rhizopus delemar-induced mucormycosis. We identified 17 cotH-like genes in the Mucor lusitanicus genome database. Successful disruption of five cotH genes was performed using the CRISPR-Cas9 system in Mucor. The CotH3 and CotH4 proteins play a role in adaptation to different temperatures as well as in developing the cell wall structure. We also show CotH4 protein is involved in spore wall formation by affecting the total chitin content and thus, the composition of the spore wall. Furthermore, we demonstrate that spore size is dependent on the cotH4 gene. The role of CotH3 and CotH4 proteins in virulence was confirmed in two invertebrate models and DKA mouse model. IMPORTANCECurrent treatment options for mucormycosis are inadequate resulting in high mortality rates especially among immunosuppressed patients. The development of novel therapies for mucormycosis has been hampered by lack of understanding of the pathogenetic mechanisms. The importance of the cell surface CotH proteins in the pathogenesis of Rhizopus-mediated mucormycosis has been recently described. However, the contribution of this family of proteins to the virulence of other mucoralean fungi and their functionality in vital processes remain undefined. Through the use of CRISPR-Case9 gene disruption system, we demonstrate the importance of several of the CotH proteins to the virulence of Mucor lusitanicus by using three infection models. We also report on the importance of one of these proteins, CotH4, to the spore wall formation through affecting the chitin content. Therefore, our studies extend the importance of CotH proteins to Mucor and identifies the mechanism by which one of the CotH proteins contributes to the development of a normal fungal cell wall, thereby indicating that this family of proteins can be targeted for future development of novel therapeutic strategies of mucormycosis.

microbiology↗

bioRxiv2022

Amphibian larvae benefit from a warm environment under simultaneous threat from chytridiomycosis and ranavirosis

Rising temperatures can facilitate epizootic outbreaks, but disease outbreaks may be suppressed if temperatures increase beyond the optimum of the pathogens while still within the temperature range that allows for effective immune function in hosts. The two most devastating pathogens of wild amphibians, Batrachochytrium dendrobatidis (Bd) and ranaviruses (Rv), co-occur in large areas, yet little is known about the consequences of their co-infection and how these consequences depend on temperature. Here we tested how co-infection and elevated temperatures (28 and 30{degrees}C vs. 22{degrees}C) affected Bd and Rv prevalence, infection intensities, and resulting mortalities in larval agile frogs and common toads. We found multiple pieces of evidence that the presence of one pathogen influenced the prevalence and/or infection intensity of the other pathogen in both species, depending on temperature and initial Rv concentration. Generally, the 30{degrees}C treatment lowered the prevalence and infection intensity of both pathogens, and, in agile frogs, this was mirrored by higher survival. These results suggest that if temperatures naturally increase or are artificially elevated beyond what is ideal for both Bd and Rv, amphibians may be able to control infections and survive even the simultaneous presence of their most dangerous pathogenic enemies.

evolutionary biology↗

bioRxiv2021

Human AdV-20-42-42, a promising novel adenoviral vector for gene therapy and vaccine product development

Pre-existing immune responses towards adenoviral vector limit the use of a vector based on particular serotypes and its clinical applicability for gene therapy and/or vaccination. Therefore, there is a significant interest to vectorize novel adenoviral types that have low seroprevalence in the human population. Here, we describe the discovery and vectorization of a chimeric human adenovirus, which we call HAdV-20-42-42. Full genome sequencing revealed that this virus is closely related to human serotype 42, except for the penton-base which is derived from serotype 20. The HAdV-20-42-42 vector could be propagated stably to high titers on existing E1-complementing packaging cell lines. Receptor binding studies revealed that the vector utilized both CAR and CD46 as receptors for cell entry. Furthermore, the HAdV-20-42-42 vector was potent in transducing human and murine cardiovascular cells and tissues, irrespective of the presence of blood coagulation factor X. In addition, the vector did not sequester in the liver upon intravenous administration in rodents. Finally, we demonstrate that potent T-cell responses against vector-delivered antigens could be induced upon vaccination. In summary, from the data obtained we conclude that HAdV-20-42-42 provides a valuable addition to the portfolio of adenoviral vectors available to develop safe and efficacious products in the fields of gene therapy and vaccination. IMPORTANCEAdenoviral vectors are currently under investigation for a broad range of therapeutic indications in diverse fields, such as oncology and gene therapy, as well as for vaccination both for human and veterinary use. A wealth of data shows that pre-existing immune responses may limit the use of a vector. Particularly in the current climate of global pandemic, there is a need to expand the toolbox with novel adenoviral vectors for vaccine development. Our data demonstrates that we have successfully vectorized a novel adenovirus serotype with low seroprevalence. The cell transduction data and antigen-specific immune responses induced in vivo demonstrate that this vector is highly promising for the development of gene therapy and vaccine products.

immunology↗