Biology subjects

Pichler, V.

Publications and source records attributed to Pichler, V..

6 recordsLinked to original sources

bioRxiv2026

Tracking kdr Alleles Associated with Pyrethroid Resistance in Aedes albopictus across Italy: A Nationwide Genotypic Dataset by MosqIRIT Network.

This data paper presents a curated, georeferenced dataset of the frequencies of the two main target site mutations (V1016G and F1534C) associated with resistance to pyrethroid insecticides in Aedes albopictus in Italy. Populations were collected in 102 out 107 Italian provinces between 2023 and 2025. Specimens were sampled by members of the Mosquito Insecticide Resistance Italian Network (MosqIRIT) as part of RN2 activities within the INF-ACT project. Genotyping was performed on 3,517 individuals by specific allele-specific PCR assays. Each record includes metadata on sampling site, administrative location, developmental stage, collection method, and mutation-specific genotype frequencies. To support spatial analysis modelling effort, the dataset integrates geographic, eco-climatic, and demographic data. This resource will support mosquito control programs, pyrethroid resistance monitoring and managing, as well as ecological modelling, and is compliant with the FAIR data program.

genetics↗

bioRxiv2024

Detection of Unlabeled Micro- and Nanoplastics in Unstained Tissue with Optical Photothermal Infrared Spectroscopy

In this study, we investigate the efficacy of Optical Photothermal Infrared (O-PTIR) spectroscopy, also known as mid-infrared photothermal (MIP) microscopy, for the detection of micro- and nano plastics (MNPs) down to diameters of 250 nm in mammalian tissues. Experiments with both in vitro 3D cell cultures derived from HTC116 colorectal cancer cell line and in vivo mouse tissue models were conducted to evaluate the spatial resolution limits and quality of spectra that formed the basis for label-free and non- destructive identification of MNPs. Our findings demonstrate the superior resolution of O-PTIR in imaging individual particles of 250 nm in mouse kidney tissues, surpassing the capabilities of traditional FTIR spectroscopy, which was applied as a reference technique. Furthermore, we introduce a semi-automated image analysis that incorporates machine learning algorithms to accelerate the detection process, thus improving throughput and minimizing the potential for human error. The results confirm that O-PTIR produces high-quality, artefact-free spectral images in a contact-less manner and significantly outperforms FTIR in terms of spatial resolution and signal-to-noise ratio in complex biological matrices.

biophysics↗

bioRxiv2024

The diversity of clinical Mycobacterium abscessus isolates in morphology, glycopeptidolipids and infection rates in a macrophage model

Mycobacterium abscessus (Mab) colonies adopt smooth (S) or rough (R) morphotypes, which are linked to the presence or absence of glycopeptidolipids (GPL), respectively. Though clinically relevant, the association between GPL levels, morphotype and pathogenesis are poorly understood. To investigate the degree of correlation between Mab morphology, GPL levels, and infectivity, we generated isolates from Mab-positive sputum samples from cystic fibrosis patients. Isolated strains were categorised based on their morphology, GPL profile, and replication rate in macrophages. Our findings revealed that around 50% of isolates displayed mixed morphologies and GPL analysis confirmed a consistent relationship between GPL content and morphotype was only found in smooth isolates. Across morphotype groups, no differences were observed in vitro, yet using a high-content THP-1 cell ex vivo infection model, clinical R strains were observed to replicate at higher levels. Moreover, the proportion of infected macrophages was notably higher among clinical R strains compared to their S counterparts at 72 hours post-infection. Clinical variants also infected at significantly higher rates compared to laboratory strains, highlighting the limited translatability of lab strain infection data to clinical contexts. Our study confirmed the general correlation between morphotype and GPL levels in smooth strains yet unveiled more variability within morphotype groups than previously recognised, particularly during intracellular infection. As the rough morphotype is of highest clinical concern, these findings contribute to the expanding knowledge base surrounding Mab infections, offering insights that can steer diagnostic methodologies, and treatment approaches.

microbiology↗

bioRxiv2022

Metabolic demands of the posteromedial default mode network are shaped by dorsal attention and frontoparietal control networks

Although BOLD signal decreases in the default mode network (DMN) are commonly observed during attention-demanding tasks, their neurobiological underpinnings are not fully understood. Previous work has shown decreases but also increases in glucose metabolism that match with or dissociate from these BOLD signal decreases, respectively. To resolve this discrepancy, we analyzed functional PET/MRI data from 50 healthy subjects during the performance of the visuo-spatial processing game Tetris(R) and combined this with previously published data sets of working memory as well as visual and motor stimulation. Our findings show that the glucose metabolism of the posteromedial DMN is dependent on the metabolic demands of the correspondingly engaged task-positive brain networks. Specifically, the dorsal attention (involved in Tetris(R)) and frontoparietal networks (engaged during working memory) shape the glucose metabolism of the posteromedial DMN in opposing directions. External attention-demanding tasks lead to a downregulation of the posteromedial DMN with consistent decreases in the BOLD signal and glucose metabolism, whereas working memory is subject to metabolically expensive mechanisms of BOLD signal suppression. We suggest that the former finding is mediated by decreased glutamate signaling, while the latter results from active GABAergic inhibition, regulating the competition between self-generated and task-driven internal demands. The results demonstrate that the DMN relates to cognitive processing in a flexible manner and does not always act as a cohesive task-negative network in isolation.

neuroscience↗

bioRxiv2021

Learning induces coordinated neuronal plasticity of metabolic demands and functional brain networks

The neurobiological basis of learning is reflected in adaptations of brain structure, network organization and energy metabolism. However, it is still unknown how different neuroplastic mechanisms act together and if cognitive advancements relate to general or task-specific changes. To address these questions, we tested how hierarchical network interactions contribute to improvements in the performance of a visuo-spatial processing task by employing simultaneous PET/MR neuroimaging before and after a 4-week learning period. We combined functional PET with metabolic connectivity mapping (MCM) to infer directional interactions across brain regions and subsequently performed simulations to disentangle the role of functional network dynamics and glucose metabolism. As a result, learning altered the top-down regulation of the salience network onto the occipital cortex, with increases in MCM at resting-state and decreases during task execution. Accordingly, a higher divergence between resting-state and task-specific effects was associated with better cognitive performance, indicating that these adaptations are complementary and both required for successful skill learning. Simulations further showed that changes at resting-state were dependent on glucose metabolism, whereas those during task performance were driven by functional connectivity between salience and visual networks. Referring to previous work, we suggest that learning establishes a metabolically expensive skill engram at rest, whose retrieval serves for efficient task execution by minimizing prediction errors between neuronal representations of brain regions on different hierarchical levels.

neuroscience↗

bioRxiv2019

Sex differences in monetary reward and punishment processing are associated with fast dynamics of dopamine synthesis

PurposeIn the human brain endogenous dopamine release is commonly assessed by the PET competition model. Although thoroughly validated, cognitive processing yields low signal changes and the assessment of several task conditions requires repeated scanning. Using the framework of functional PET imaging we introduce a novel approach which leverages the incorporation of the radioligand 6-[18F]FDOPA into the dynamic fast-acting regulation of the corresponding enzyme activities by neuronal firing and neurotransmitter release. We demonstrate the feasibility of the approach by the assessment of widely described sex differences in dopamine neurotransmission. MethodsReward and punishment processing was behaviorally investigated in 36 healthy participants, where 16 underwent fPET and fMRI while performing the monetary incentive delay task. 6-[18F]FDOPA was applied as bolus+infusion during a single 50 min PET acquisition. Task-specific changes in dopamine synthesis were identified with the general linear model and quantified with the Gjedde-Patlak plot. ResultsMonetary gain induced 78% increase in nucleus accumbens dopamine synthesis vs. 49% for loss in men. Interestingly, the opposite was discovered in women (gain: 51%, loss: 78%). Behavioral modeling revealed direct associations of task-specific dopamine synthesis with reward sensitivity in men (rho = -0.7) and with punishment sensitivity in women (rho = 0.89). As expected, fMRI showed robust task-specific neuronal activation but no sex difference. ConclusionsOur findings provide a dopaminergic basis for well-known behavioral differences in reward and punishment processing between women and men. This has important implications in psychiatric conditions showing sex-specific prevalence rates, altered reward processing and dopamine signaling. The high temporal resolution and pronounced magnitude of task-specific changes make fPET a promising tool to investigate functional neurotransmitter dynamics during cognitive or emotional processing in various brain disorders.

neuroscience↗