Biology subjects

Masuzzo, A.

Publications and source records attributed to Masuzzo, A..

3 recordsLinked to original sources

bioRxiv2025

Genome-wide association studies identify new candidate genes and tissues underlying resistance to a natural toxin in drosophilids

Many insects can rapidly evolve resistance to artificial insecticides through changes in toxin target proteins. Over longer timescales, insects have also evolved resistance to naturally-occurring toxins to exploit new ecological niches, but much less is known about the mechanisms underlying such adaptations. A classic example is Drosophila sechellia, an extreme specialist for the ripe noni fruit of Morinda citrifolia, which is toxic for other insects - including the close relatives D. simulans and D. melanogaster - due to nonis high content of octanoic acid (OA). The mechanistic bases underlying susceptibility and resistance to OA of different species remain unclear. Here, we first show that the species-specific tolerance of OA is independent of these drosophilids distinct microbiomes, reinforcing the notion that this trait is genetically encoded. Screening large, genetically-diverse panels of D. melanogaster and D. simulans strains revealed broad variation in OA resistance, with some lines surviving as well as D. sechellia. Resistance to OA does not correlate with resistance of these lines to other insecticides, implying a distinct toxicity mode-of-action. Genome-wide association and transcriptome-to-phenotype analyses identified multiple genes linked to OA resistance. These genes have diverse expression patterns and functions, including proteins involved in epithelial septate junction formation, lipid transport and tracheal morphogenesis. Loss-of-function analysis in D. melanogaster confirmed that at least two of these - Bez, a CD36-family fatty acid transporter, and CG13003, a putative extracellular matrix component - positively contribute to OA resistance. Integration of our findings with those from previous complementary genetic approaches supports a model in which OA has no singular target, and that resistance to this toxin is defined by multigenic and multi-tissue defense mechanisms.

evolutionary biology↗

bioRxiv2024

Drosophila's sensory responses to bacterial peptidoglycan integrates positive and negative signals

Interactions between animals, including humans, and surrounding microbes are governed by a delicate balance, crucial for survival. Animals must distinguish and respond adequately to beneficial and harmful microbes to maintain homeostasis. Recent research suggests that bacterial components such as lipopolysaccharide and peptidoglycan (PGN) influence host behavior by modulating neuronal activity. PGN detection by specific neurons can prompt infected female flies to reduce oviposition or trigger avoidance behaviors via gustatory neurons. Using behavioral assays and calcium imaging, we found that PGNs can also act as attractants, activating the sweet taste circuit in a concentration-dependent manner. Our findings demonstrate that flies integrate PGN-derived positive and negative signals to make ad hoc decisions. This dual response underlines the need for Drosophila to distinguish between different concentrations of compounds in their environment, integrating sensory data to navigate efficiently in microbe-co-inhabited environments. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/626038v3_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@8aab21org.highwire.dtl.DTLVardef@1e90d09org.highwire.dtl.DTLVardef@156f1d4org.highwire.dtl.DTLVardef@11ed69c_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights- Bacterial PGN is attractive to flies - Gr5a sweet gustatory neurons are activated by PGN - Adult PER to PGN is not directly influenced by larval life - Fly gustatory response to PGN integrates both attractive and aversive signals

animal behavior and cognition↗

bioRxiv2021

Bacteria-derived peptidoglycan triggers an NF-kB dependent response in Drosophila gustatory neurons

Probing the external world is essential for eukaryotes to distinguish beneficial from pathogenic microorganisms. If it is clear that this task falls to the immune cells, recent work shows that neurons can also detect microbes, although the molecules and mechanisms involved are less characterized. In Drosophila, detection of bacteria-derived peptidoglycan by pattern recognition receptor (PRR) of the PGRP family expressed in immune cells, triggers NF-{kappa}B/IMD dependent signaling. We show here that one PGRP protein, called PGRP-LB, is expressed in some probosciss bitter taste neurons. In vivo calcium imaging reveals that the PGRP/IMD pathway is cell-autonomously required in these neurons to transduce the PGN signal. We finally show that NF-{kappa}B/IMD pathway activation in bitter neurons influences fly behavior. This demonstrates that flies use the same bacterial elicitor and signaling module to sense bacterial presence via the peripheral nervous system and trigger an anti-bacterial response in immune-competent cells.

neuroscience↗