Biology subjects

Calevro, F.

Publications and source records attributed to Calevro, F..

8 recordsLinked to original sources

bioRxiv2026

Neprilysin 1 in the Mushroom Body controls Feeding behavior by regulating SIFamide levels in Drosophila melanogaster

Feeding-related behavior in Drosophila melanogaster encompasses olfactory and gustatory detection of odors, foraging, and food intake. In Drosophila melanogaster, the neuropeptide SIFamide (SIFa), has been shown to integrate hunger signals to promote feeding in Drosophila and is considered a central regulator of mutually exclusive behavioral states. Here, we identify the mushroom bodies as a key downstream circuit of SIFamidergic neurons for regulation of food-seeking and feeding. Furthermore, we show that mushroom bodies are not merely downstream effectors but actively shape SIFamidergic signaling through the peptidase Neprilysin 1 for which SIFamide is a substrate. Thus, SIFa signaling is embedded within a feedforward-feedback circuit that couples internal state to the selection and execution of feeding behavior. We propose that the distinct neuronal subtypes postsynaptic to the elaborately arborized SIFamidergic neurons define discrete neuronal subroutines that differentially control the mutually exclusive behaviors related to sexual reproduction, sleep and feeding. Our findings reveal an evolutionary ancient peptidergic system that is modified by recruitment of novel genes for the flexible control of distinct behavioral programs and feeding strategies.

animal behavior and cognition↗

bioRxiv2025

ArtSymbioCyc, a metabolic network database collection dedicated to arthropod symbioses: a case study, the tripartite cooperation in Sipha maydis

Most arthropods live in close association with bacteria. The genomes of associated partners have co-evolved creating situations of interdependence that are complex to decipher despite the availability of their complete sequences. We developed ArtSymbioCyc, a metabolism-oriented database collection gathering genomic resources for arthropods and their associated bacteria. ArtSymbioCyc uses the powerful tools of the BioCyc community to produce high quality annotations and to analyze and compare metabolic networks on a genome-wide scale. We used ArtSymbioCyc to study the case of the tripartite symbiosis of the cereal aphid Sipha maydis focusing on amino acid and vitamin metabolisms, as these compounds are known to be important in this strictly phloemophagous insect. We showed how the metabolic pathways of the insect host and its two obligate bacterial associates are interdependent and specialized in the exploitation of Poaceae phloem, for example for the biosynthesis of sulfur-containing amino acids and most vitamins. This demonstrates that ArtSymbioCyc does not only reveal the individual metabolic capacities of each partner and their respective contributions to the holobiont they constitute, but also allows to predict the essential inputs that must come from host nutrition. IMPORTANCEEvolution has driven the emergence of complex arthropod-microbe symbiotic systems, whose metabolic integration is difficult to unravel. With its user-friendly interface, ArtSymbioCyc (https://artsymbiocyc.cycadsys.org) eases and speeds up the analysis of metabolic networks by enabling precise inference of compound exchanges between associated partners, and helps unveil the adaptive potential of arthropods in contexts such as conservation or agricultural control.

bioinformatics↗

bioRxiv2025

Cadmium tolerance is associated with tissue-specific plasticity of metallothionein gene expression in Gammarus fossarum field populations

The metallothionein gene family codes for proteins involved in metal homeostasis and acute detoxification of non-essential toxic metal ions across the tree of life. We have previously documented increased cadmium (Cd) tolerance in field populations of the crustacean Gammarus fossarum exposed to chronic metallic contamination of geochemical origin. This tolerance is lost during maintenance of organisms in the laboratory, and is transmitted to offspring via parental effects. This study investigated whether the expression of the Cd-responsive metallothionein gene mt1 could be related to Cd-tolerance plasticity in G. fossarum. In eleven populations with different chronic Cd exposure history, we simultaneously assessed Cd-tolerance (mortality tests) and G. fossarum mt1 expression levels by RT-qPCR in the gills and caeca of adult males and in neonates. mt1 expression levels in the two organs were correlated to Cd-tolerance in field organisms and a loss of tolerance was observed in parallel with a decreased expression of mt1 in the caeca after maintenance in uncontaminated water. We also recorded a greater inducibility of mt1 expression in offspring of tolerant populations in the laboratory when re-exposed to Cd along with the bi-parental transmission of Cd-tolerance. These results suggest that the control of mt1 expression is involved in the plasticity of Cd-tolerance in gammarid populations with different histories of Cd exposure. Highlights- mt1 gene expression in the gills and in the hepatopancreatic caeca is associated with Cd tolerance in Gammarus fossarum populations. - Plasticity of G. fossarum mt1 gene expression is associated to loss of Cd tolerance. - Parental effect in Cd tolerance is supported by transgenerational control of mt1 expression, underlid by an increased induction of mt1 during Cd exposure.

evolutionary biology↗

bioRxiv2024

Proteogenomic reconstruction of organ-specific metabolic networks in an environmental sentinel species, the amphipod Gammarus fossarum

Metabolic pathways are targets of environmental contaminants underlying a large variability of toxic effects throughout biodiversity. However, the systematic reconstruction of metabolic pathways remains limited in environmental sentinel species due to the lack of available genomic data in many taxa of animal diversity. In order to improve the knowledge of the metabolism of sentinel species, in this study we used a multi-omics approach to reconstruct the most comprehensive map of metabolic pathways for a crustacean model in biomonitoring, the amphipod Gammarus fossarum. We revisited the assembly of RNA-seq data by de novo approaches drastically reducing RNA contaminants and transcript redundancy. We also acquired extensive mass spectrometry shotgun proteomic data on several organs from G. fossarum males and females to identify organ-specific metabolic profiles. The G. fossarum metabolic pathway reconstruction (available through the metabolic database GamfoCyc) was performed by adapting the genomic tool CycADS and we identified 377 pathways representing 7,630 annotated enzymes, 2,610 enzymatic reactions and the expression of 858 enzymes was experimentally validated by proteomics. Our analysis shows organ-specific metabolic profiles, such as an elevated abundance in enzymes involved in ATP biosynthesis and fatty acid beta-oxidation indicative of the high-energy requirement of the gills, or the key anabolic and detoxification role of the hepatopancreatic caeca, as exemplified by the specific expression of the retinoid biosynthetic pathways and glutathione synthesis. In conclusion, the multi-omics data integration performed in this study provides new resources to investigate metabolic processes in crustacean amphipods and their role in mediating the effects of environmental contaminant exposures in sentinel species.

molecular biology↗

bioRxiv2022

The di-symbiotic systems in the aphids Sipha maydis and Peryphillus lyropictus provide a contrasting picture of recent co-obligate nutritional endosymbiosis in aphids

Dependence on multiple nutritional bacterial symbionts forming a metabolic unit has repeatedly evolved in many insect species that feed on nutritionally unbalanced diets such as plant sap. This is the case for aphids of the subfamilies Lachninae and Chaitophorinae, which have evolved di-symbiotic systems in which the ancient obligate nutritional symbiont Buchnera aphidicola is metabolically complemented by an additional nutritional symbiont acquired more recently. Deciphering how different symbionts integrate both metabolically and anatomically in such systems is crucial to understanding how complex nutritional symbiotic systems function and evolve. In this study, we sequenced and analyzed the genomes of the symbionts B. aphidicola and Serratia symbiotica associated with the Chaitophorinae aphids Sipha maydis and Periphyllus lyropictus. Our results show that, in these two species, B. aphidicola and S. symbiotica complement each other metabolically (and their hosts) for the biosynthesis of essential amino acids and vitamins but with distinct metabolic reactions supported by each symbiont depending on the host species. Furthermore, the S. symbiotica symbiont associated with S. maydis appears to be strictly compartmentalized into the specialized host cells housing symbionts in aphids, the bacteriocytes, whereas the S. symbiotica symbiont associated with P. lyropictus exhibits a highly invasive phenotype, presumably because it is capable of expressing a larger set of virulence factors, including a complete flagellum for bacterial motility. Such contrasting levels of metabolic and anatomical integration for two S. symbiotica symbionts that were recently acquired as nutritional co-obligate partners reflect distinct coevolutionary processes specific to each association.

microbiology↗

bioRxiv2021

The aphid BCR4 structure and activity uncover a new defensin peptide superfamily

Aphids (Hemiptera: Aphidoidea) are among the most injuring insects for agricultural plants and their management is a great challenge in agronomical research. A new class of proteins, called Bacteriocyte-specific Cysteine-Rich (BCR), provides an alternative to chemical insecticides for pest control. BCRs have been initially identified in the pea aphid Acyrthosiphon pisum. They are small disulfide bond-rich proteins expressed exclusively in aphid bacteriocytes, the insect derived cells that host intracellular symbiotic bacteria. Here, we show that one out of the A. pisum BCRs, BCR4, displays an outstanding insecticidal activity against the pea aphid, impairing insect survival and nymphal growth, providing evidence for its potential use as a new biopesticides. Our comparative genomics and phylogenetic analysis indicate that BCRs seem restricted to the aphid lineage. The 3D structure of the BCR4 reveals that this peptide belongs to a yet unknown structural class of peptides and defines a new superfamily of defensins.

biochemistry↗

bioRxiv2021

The genome sequence of the cereal pest Sitophilus oryzae: an unprecedented transposable element content

BackgroundThe rice weevil Sitophilus oryzae is one of the most important agricultural pests, causing extensive damage to cereal in fields and to stored grains. S. oryzae has an intracellular symbiotic relationship (endosymbiosis) with the Gram-negative bacterium Sodalis pierantonius and is a valuable model to decipher host-symbiont molecular interactions. ResultsWe sequenced the Sitophilus oryzae genome using a combination of short and long reads to produce the best assembly for a Curculionidae species to date. We show that S. oryzae has undergone successive bursts of transposable element (TE) amplification, representing 72% of the genome. In addition, we show that many TE families are transcriptionally active, and changes in their expression are associated with insect endosymbiotic state. S. oryzae has undergone a high gene expansion rate, when compared to other beetles. Reconstruction of host-symbiont metabolic networks revealed that, despite its recent association with cereal weevils (30 Kyear), S. pierantonius relies on the host for several amino acids and nucleotides to survive and to produce vitamins and essential amino-acids required for insect development and cuticle biosynthesis. ConclusionsHere we present the genome of an agricultural pest beetle, which may act as a foundation for pest control. In addition, S. oryzae may be a useful model for endosymbiosis, and studying TE evolution and regulation, along with the impact of TEs on eukaryotic genomes.

genomics↗

bioRxiv2019

Commensal bacteria differentially shape the nutritional requirements of Drosophila during juvenile growth

The interplay between nutrition and the microbial communities colonizing the gastro-intestinal tract (i.e. gut microbiota) determines juvenile growth trajectory. Nutritional deficiencies trigger developmental delays, and an immature gut microbiota is a hallmark of pathologies related to childhood undernutrition. However, how commensal bacteria modulate the impact of nutrition on juvenile growth remains elusive. Here, using gnotobiotic Drosophila melanogaster larvae independently associated with two model commensal bacterial strains, Acetobacter pomorumWJL (ApWJL) and Lactobacillus plantarumNC8 (LpNC8), we performed a large-scale, systematic nutritional screen based on larval growth in 40 different and precisely controlled nutritional environments. We combined these results with genome-based metabolic network reconstruction to define the biosynthetic capacities of Drosophila germ-free (GF) larvae and its two commensal bacteria. We first established that ApWJL and LpNC8 differentially fulfills the nutritional requirements of the ex-GF larvae and parsed such difference down to individual amino acids, vitamins, other micronutrients and trace metals. We found that Drosophila commensal bacteria not only fortify the hosts diet with essential nutrients but, in specific instances, functionally compensate for host auxotrophies, by either providing a metabolic intermediate or nutrient derivative to the host or by uptaking, concentrating and sparing contaminant traces of micronutrients. Our systematic work reveals that, beyond the molecular dialogue engaged between the host and its commensal partners, Drosophila and its facultative bacterial partners establish an integrated nutritional network relying on nutrients sparing and utilization.

physiology↗