Biology subjects

Horvath, G.

Publications and source records attributed to Horvath, G..

7 recordsLinked to original sources

bioRxiv2026

Microplastics disrupt adaptive predator-induced behavioural plasticity in Rana dalmatina tadpoles

The accumulation of microplastics (MP; plastic particles 1 m - 1 mm in diameter) in the environment is an increasing global concern. Although the physiological effects of MP on organisms, including humans, are increasingly documented, their impacts on behaviour are far less understood. Further, little is known about how MP affect adaptive phenotypic plasticity - the ability of a genotype to adaptively modify its phenotype in response to environmental cues. Anuran tadpoles are key models for studying phenotypic plasticity, with well-established evidence for predator-induced behavioural adjustments. Tadpoles typically reduce their activity and risk-taking when exposed to chemical cues released by predators, which has been proven to be adaptive. We investigated whether MP exposure from the fertilised egg stage alters the behaviour of agile frog (Rana dalmatina) tadpoles, and whether it interferes with their predator-induced behavioural plasticity. Tadpoles exposed to chemical cues from dragonfly larvae showed the expected antipredator response: these larvae showed significantly reduced movement activity and risk-taking. Although exposure to MP did not influence the behaviour of tadpoles that had not been exposed to predator cues, and also did not alter predator-induced changes in movement activity, it entirely abolished the predator-induced reduction in risk-taking. These results indicate that MP can compromise antipredator behaviour, increasing the vulnerability of individuals and natural populations to predation without causing visible developmental abnormalities. We recommend that future MP research targets behavioural traits with direct relevance to survival and reproduction, and examines how adaptive phenotypic plasticity is affected.

animal behavior and cognition↗

bioRxiv2026

Conflicting binocular input triggers inhibition followed by rebound, explaining paradoxically fast reaction times

Binocular vision depends on the integration of matching visual features across the two eyes, while conflicting interocular signals can engage active inhibitory processes in the visual system. To investigate the temporal dynamics of these putative inhibitory processes, we examined how transitions between different binocular correlation states influence perceptual detectability and response speed. Using dynamic random-dot correlograms - free of monocular cues and allowing precise interocular manipulation - we presented brief target intervals embedded in longer background sequences. Stimuli varied in binocular correlation: correlated (C) patterns contained identical luminance profiles in both eyes, anticorrelated (A) patterns had inverted luminance dots, and uncorrelated (U) patterns had independent dot arrangements. Across three experiments, we measured (1) the presentation duration threshold required to detect a change in correlation, (2) simple reaction times (RTs) to the same transitions at suprathreshold levels, and (3) psychometric functions across durations for selected transitions. In Experiment 1, A[->]C transitions yielded significantly higher duration thresholds than C[->]A, indicating a suppressive influence associated with prior anticorrelation. In contrast, Experiment 2 showed that A[->]C transitions produced the shortest RTs, while C[->]U transitions were slowest, suggesting a rebound-like facilitation following prior suppression. Experiment 3 confirmed these temporal and contrast dependences, with opposite changes in contrast threshold and reaction times between transitions toward and away from the correlated fusional states. This divergence between perceptual onset and reaction time is consistent with a two-phase account in which binocular anticorrelation is associated with an initial suppressive phase followed by rebound-like facilitation that accelerates responses once the target becomes detectable. These findings are consistent with current models of binocular rivalry and fusion, and provide a temporally resolved behavioral perspective on how inhibitory control in sensory systems may dynamically influence subsequent responsiveness under conditions of perceptual ambiguity.

neuroscience↗

bioRxiv2026

A comparison of commercially available Saccharomyces mead yeasts.

We present a comparative analysis of 13 yeasts available for mead (honey wine) fermentation, a source of Saccharomyces cerevisiae diversity that has not yet been analyzed in detail. Using genomic, phenotyping, and analytic methods, we show that currently available mead yeasts belong to various clades of the species, most commonly to the Commercial Wine clade (5 of 13 samples). Mead yeasts in this group displayed genome structure variations and occasional loss of killer activity, despite being closely related. Historic European and traditional African mead isolates with sequenced genomes were found not to be closely related to any contemporary mead yeast product. The 13 yeasts tested here displayed high variability in oenological characteristics and in aroma production. Maximum ethanol tolerance ranged from 15 to 22% v/v, however, the most tolerant strain produced lower ethanol levels and retained high fructose content in experimental meads. The most abundant aroma components produced in meads were ethyl acetate, ethyl caprylate, isoamyl alcohol, and ethyl caprate, with similar aroma profiles in members of the Commercial Wine clade, and pronounced differences among other yeasts. Our results contribute to the knowledge of Saccharomyces yeasts in various fermentation environments, adding mead to the list of alcoholic beverages with a known diversity of starter cultures. Our results may aid strain selection for honey wine fermentations and inspire strain improvement.

microbiology↗

bioRxiv2025

Reptilian hunchbacks: a systematic review and meta-analysis of spinal deformities in wild reptiles.

Deformities of the spinal column--such as kyphosis, scoliosis, lordosis, and their various combinations--are known to affect all major vertebrate taxa. In reptiles, these deformities are relatively common in captivity, but reports from wild populations are also frequent. Since the 2000s, the number of published cases and affected species has increased considerably. However, most observations still appear as natural history notes or brief reports, often treating spinal deformities as mere curiosities without examining their aetiology, pathology, or prevalence. As a result, we know virtually nothing about the potential ecological impacts of spinal deformities on the life history of affected individuals or populations. Here, based on a systematic review of peer-reviewed and grey literature, complemented by unpublished observations gathered through standardized social media inquiries, I present the most comprehensive database and review of spinal deformities in wild reptiles to date. I identified 351 observations from 139 sources, covering 103 species across 24 families and 35 countries. Unpublished observations accounted for 13.3% of the database. Spinal deformities appear across all major reptile clades, though Testudines are clearly overrepresented (59.8%), likely due to their greater popularity, visibility, and research attention compared to other groups. Prevalence data were available or could be extracted from 51 records (36 species). A phylogenetic meta-analysis revealed a global prevalence effect size of 0.23%. However, no significant effects of phylogeny, habitat use strategy, or habitat type were detected--though this may reflect limitations of the dataset. Kyphosis appeared more frequently in (semi)aquatic Testudines than in primarily terrestrial squamates, whereas the opposite pattern was observed for scoliosis. Nonetheless, the underrepresentation of (semi)aquatic squamate taxa in the dataset urges caution when interpreting these phylogenetic inferences. Spinal deformities may substantially impact key life-history traits such as survival, growth, and reproduction, but direct evidence remains scarce and mostly anecdotal. To enhance ecological relevance, future studies should adopt more detailed and standardized reporting-- incorporating occurrence frequency, habitat characteristics, morphometrics, imaging data, and assessments of behavioural or locomotor limitations.

ecology↗

bioRxiv2025

The Cause of Most Common Antler Abnormality is Not a Fracture But an Osteomyelitis Like Disease the Pedunculitis Chronica Deformans

Climate change is increasing the incidence of certain diseases in wildlife, offering a deeper understanding of their underlying causes. Traditionally, the most common antler abnormalities have been attributed to trauma, based on their morphology. However, this explanation does not account for the epidemic-like spread of abnormalities in specific regions, suggesting that they might be a previously undescribed aspect of this anomaly. In fallow deer (Dama dama), using advanced medical diagnostic tools, we identified an osteomyelitis-like condition, Pedunculitis Chronica Deformans (PCD) which is also observed in other Cervidae. The incidence of this disease shows a strong correlation with the production of mycotoxins by molds that are becoming more prevalent with global warming. Mycotoxins can inhibit wound healing through scar formation after the antlers are cast, leading to the development of PCD. In this report we characterize PCD pathomorphology and introduce a scoring system to differentiate it from other deformities. Moreover, we argue that the most common anomalies such as fractures, antler losses, fatal meningoencephalitis and brain abscesses are complications of PCD. Our research underscores the potential of antlers to serve as biomarkers for mycotoxin exposure.

zoology↗

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↗

bioRxiv2017

Diagnostic Yield And Treatment Impact Of Targeted Exome Sequencing In Early-Onset Epilepsy

BackgroundTo examine the impact on diagnosis, treatment and cost with early use of targeted whole-exome sequencing (WES) in early-onset epilepsy.\n\nMethodsWES was performed on 50 patients with early-onset epilepsy ([≤] 5 years) of unknown cause. Patients were classified as retrospective (epilepsy diagnosis > 6 months) or prospective (epilepsy diagnosis < 6 months). WES was performed on an Ion ProtonTM and variant reporting was restricted to the sequences of 565 known epilepsy genes. Diagnostic yield and time to diagnosis were calculated. An analysis of cost and impact on treatment was also performed.\n\nResultsA likely/definite diagnosis was made in 17/50 patients (34%) with immediate treatment implications in 8/17 (47%). A possible diagnosis was identified in 9 additional patients (18%) for whom supporting evidence is pending. Time from epilepsy onset to genetic diagnosis was faster when WES was performed early in the diagnostic process (mean: 143 days prospective versus 2,172 days retrospective). Costs of prior negative tests averaged $8,344 in the retrospective group, suggesting savings of up to $5,110 per patient.\n\nInterpretationThese results support the clinical utility and potential cost-effectiveness of using targeted WES early in the diagnostic workup of patients with unexplained early-onset epilepsy. The costs and clinical benefits are likely to continue to improve. Advances in precision medicine and further studies regarding impact on long-term clinical outcome will be important.

genetics↗