Biology subjects

Aleman, M.

Publications and source records attributed to Aleman, M..

3 recordsLinked to original sources

bioRxiv2026

Developmental Olfactory Experience Dissociates Hedonic Valence from Exploratory Arousal in Drosophila melanogaster

Insects rely on olfactory cues to navigate complex environments, with many innate behaviors governed by evolutionary hardwired neural circuits. However, the extent to which early-life sensory experience can recalibrate these innate responses remains a subject of intense debate. Here, we investigate how chronic exposure to odorants of varying innate valences during development and early adulthood modulates olfactory preference and exploratory drive in Drosophila melanogaster. Using a high-resolution two-choice assay, we demonstrate a fundamental functional dissociation in olfactory plasticity: while the innate hedonic valence of most odorants remains remarkably resilient to developmental environmental manipulation, early-life experience profoundly reprograms exploratory dynamics. Specifically, chronic exposure to propionic acid and benzaldehyde induced sex-specific shifts in locomotor arousal and trap-entry decisions without altering the intrinsic hedonic valuation of the stimuli. Conversely, general exploratory drive toward 1-octanol and isoamyl acetate remained rigidly hardwired, although 1-octanol exhibited subtle, experience-dependent habituation in odor preference. This resilience of innate valence suggests that the olfactory circuit actively prioritizes functional stability to ensure that critical ecological cues remain reliably encoded. Our findings reveal that Drosophila employs a modular adaptive strategy to integrate chronic sensory information: unreinforced early-life experience selectively reconfigures motor reactivity to scale navigational intensity to familiar landscapes, while leaving primary sensory-driven valences largely intact.

neuroscience↗

bioRxiv2024

Bats from the Colombian Caribbean Reveal a new subtype of Influenza A (H18N12)

Influenza viruses have an excellent capacity for mutation and adaptation in mammalian hosts, which makes them viruses of medical and veterinary importance. Influenzaviruses have been studied mainly in birds but minor in bats. It is unknown whether Chiroptera are reservoirs of influenza viruses. However, circulation in bats showed molecular divergence from H17N10 (Guatemala) and H18N11 (Peru), and they were designated as new subtypes. The study aimed to characterize the influenza A virus detected in the fishing bat Noctilio albiventris. A surveillance study of pathogens of public health interest was carried out; rectal samples were taken from four fishing bats (N. albiventris) captured in Talaigua Nuevo, Bolivar, Colombia. The samples were sequenced by NGS using DNBseq (MGI-G50(R)) and analyzed with bioinformatics tools. Eight viral contigs associated with the Orthomyxoviridae family were obtained. The identified segments showed around 90% similarity with H18N11, except for the neuraminidase (N). The phylogenetic analysis of the N protein showed the appearance of a basal branch to the N11 subtype, and the molecular clock indicates that it does not share a recent common ancestor. 3D modeling indicates that the N protein of N. albiventris presents three mutations (K363R, T242K, and I139V) near the hypothetical active site of the protein. These mutations potentially increase the interaction with the HLA-DR of bats, which could have significant implications for the viruss behavior. The phylogenetic, evolutionary, and antigenic divergence of the N protein of N. albiventris suggests a new subtype called H18N12. Its role as a pathogen must be studied.

bioinformatics↗

bioRxiv2024

L-Dopa incorporation into tubulin alters microtubule dynamics and reduces dendritic spine invasion and synapse maintenance

Previous studies have shown that L-Dopa, a tyrosine analog used in Parkinsons disease treatment, can be incorporated into -tubulin C-terminal tail via the tubulin tyrosine ligase (TTL) and polymerize into microtubules. In this work, we demonstrated that mature wild type hippocampal neurons treated with L-Dopa exhibited reduced dendritic spine density, primarily affecting mature dendritic spines. In these neurons, L-Dopa treatment significantly reduced tyrosinated -tubulin levels without altering detyrosinated or {Delta}2 -tubulin levels, suggesting the formation of a new tubulin pool, likely composed of L-Dopa--tubulin. In vitro analysis of the activity of the purified VASH1-SVBP complex, the most abundant tubulin carboxypeptidase in brain, revealed that L-Dopa incorporation into -tubulin modified the binding of the complex to microtubules and reduced its carboxypeptidase activity. These results suggest that L-Dopa incorporation into tubulin alters the properties of microtubules and affects their ability to interact with the enzyme. To confirm the implication of L-Dopa-microtubules in dendritic spine alterations observed in wild type neurons, we analyzed the effect of L-Dopa treatment in neurons lacking the enzymes of the -tubulin detyrosination/tyrosination cycle. In these cells, L-Dopa cannot be incorporated into -tubulin due to the absence of the ligase (in TTL KO neurons) or the reduction of detyrosinated -tubulin levels (in SVBP KO neurons). L-Dopa treatment did not modify dendritic spine density in TLL KO or SVBP KO neurons, clearly demonstrating that the alterations in dendritic spines seen in WT neurons are due to the incorporation of L-Dopa into tubulin. Further analysis revealed that L-Dopa treatment decreased the percentage of spines containing excitatory synapses in wild type neurons, but not in TTL KO or SVBP KO neurons, suggesting a cumulative synaptic defect due to L-Dopa incorporation into microtubules. Additionally, L-Dopa altered microtubule dynamics by increasing catastrophe frequency and reducing comet lifetime, which led to fewer microtubules entering dendritic spines and decreased spine resistance to pruning. Taken together, our results demonstrate that L-Dopa incorporation into -tubulin drastically affects synaptic homeostasis, reaffirming the importance of balanced detyrosination/tyrosination of tubulin within the synaptic compartment. The abnormal dynamics of L-Dopa-microtubules and the reduction of dendritic spines and excitatory synapses highlight a novel mechanism of L-Dopa-induced synaptotoxicity.

neuroscience↗