Biology subjects

Charles, H.

Publications and source records attributed to Charles, H..

3 recordsLinked to original sources

bioRxiv2023

Diversity of Insecticidal PA1b Homologs among Legume Seeds from Middle Eastern Region

Legumes play a central role in various food systems, with significant socio-economic and environmental impacts. Their high protein content, composed mainly of globulins and albumins, makes them valuable for human food and animal feed. Among the albumins, is Pea Albumin 1 b (PA1b), a 37 amino acid peptide, extracted from the seeds of the pea Pisum sativum. The protein displays the knottin scaffold and exhibits potent insecticidal activity against certain insects including cereal weevils and mosquitoes. This toxicity is attributed to the coexistence of several isoforms in peas. The natural diversity of PA1b-like molecules within the legume species of the Fabaceae family has been studied using various molecular, biochemical, and bioinformatic tools. Several A1 genes coding for this peptide have been characterized in soybeans, bean, barrel medick and other legume species. The aim of is study is to precisely characterize partial A1 genes in legumes of the Faboideae subfamily from the Middle East region using PCR homology. Specifically, the research focuses on the sequence structure of Pea Albumin 1 b (PA1b) variants and establishes phylogenetic relationships between these sequences and publicly available A1b homologs. The toxic effects of seed flour containing PA1b-like molecules are assessed, demonstrating that the newly characterized PA1b homologs retain structural conservation. The study observes both conservation and diversification among A1b homologs, consistent with the divergence of lineages within the Fabaceae family. The toxic effects associated with putative A1b molecules are found across different species and within the same species from different geographical origins. In particular, novel candidates such as Vicia sativa and Medicago minima show promising insecticidal A1b activity. Further analysis of isoforms from these species, including an examination of their expression in different tissues and organs should be undertaken to facilitate the potential use of A1b molecules in agricultural practice.

bioinformatics↗

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↗