Biology subjects

Dellinger, J.

Publications and source records attributed to Dellinger, J..

3 recordsLinked to original sources

bioRxiv2024

AtVPS13M1 is involved in lipid remodeling in low phosphate and is located at the mitochondria surface in plants

VPS13 are conserved lipid transporters with multiple subcellular localizations playing key roles in many fundamental cellular processes. While the localization and function of VPS13 have been extensively investigated in yeast and animals, little is known about their counterparts in plants, particularly regarding their role in stress response. In this study, we characterized AtVPS13M1, one of the four VPS13 paralogs of the flowering plant Arabidopsis thaliana. We show that AtVPS13M1 binds and transports glycerolipids with a low specificity in vitro. AtVPS13M1 interferes with phospholipids degradation in response to phosphate starvation, a nutrient stress that triggers a massive remodeling of membrane lipids. AtVPS13M1 is mainly expressed in young dividing and vascular tissues. Finally, we show that AtVPS13M1 is mainly located at the surface of mitochondria in leaves. Overall, our work highlights the conserved role in lipid transport of VPS13 in plants, reveals their importance in nutrient stress response and opens important perspectives for the understanding of lipid remodeling mechanisms and for the characterization of this protein family in plants.

cell biology↗

bioRxiv2024

Semaglutide interferes with postnatal growth in a diet-dependent manner

GLP-1 receptor agonists, including semaglutide, are increasingly used to treat obesity--and to a lesser extent, type 2 diabetes--in children and adolescents. Despite their therapeutic promise, the impact of semaglutide on key endocrine and metabolic developmental processes during this period is not yet fully understood. To address the limited understanding of GLP-1 receptor agonists during development, we investigated the effects of chronic semaglutide treatment on growth and metabolism of weanling male mice. In juvenile mice displaying a normal growth pattern, semaglutide lowered blood glucose without affecting food intake or weight gain. In contrast, chronic semaglutide treatment in growth-stunted juveniles exacerbated linear growth impairment, despite preserving glucose-lowering effects. Transcriptomic analysis of the liver, complemented by gene expression studies in other metabolically active tissues, suggested altered energy expenditure, indicating a complex interaction between semaglutide, energy metabolism, and growth during juvenile development. These findings underscore the importance of developmental context when evaluating the safety and efficacy of GLP-1 receptor agonists in pediatric populations.

physiology↗

bioRxiv2022

New insights from short and long reads sequencing to explore cytochrome b variants of Plasmopara viticola populations collected in vineyard and related to resistance to complex III inhibitors

Downy mildew is caused by Plasmopara viticola, an obligate oomycete plant pathogen, a devasting disease for grapevine. To preserve plants from the disease, complex III inhibitors are among the widely used fungicides that specifically target the mitochondrial cytochrome b (cytb) of the pathogen to block cellular respiration mechanisms. In French vineyard, P. viticola developed resistance against a first category of these fungicides, the Quinone outside inhibitors, by exhibiting a single amino acid substitution G143A in its cytb mitochondrial sequence. Their usage was restricted and another kind of fungicides, Quinone inside inhibitors, targeting the same gene and highly effective against oomycetes, were used instead. Recently however, less sensitive P. viticola populations were detected after treatments with some inhibitors, in particular ametoctradin and cyazofamid. By isolating resistant single-sporangia strains of P. viticola to these fungicides, we characterized new variants in cytb sequences associated with cyazofamid resistance: a point mutation (L201S) and more strikingly, two insertions (E203-DE-V204, E203-VE-V204). In parallel with classical tools, pyrosequencing and RT-PCR, we then benchmarked both short and long-reads NGS technologies (Ion Torrent, Illumina, Oxford Nanopore Technologies) to sequence the complete cytb with the prospect to detect and assess the proportion of resistant variants of P. viticola at a natural population scale. Eighteen populations collected from French vineyard fields in 2020 were analysed: 12 show a variable proportion of G143A, 11 of E203-DE-V204 and 7 populations of the S34L variant that confers resistance to ametoctradin. Interestingly, long reads were able to identify variants, including SNPs, with confidence and detect a small proportion of P. viticola showing several variants along the same cytb sequence. Altogether, NGS appear promising methods to evaluate pathogen resistance towards fungicides related to cytb modifications at a population scale in the field. This approach could be rapidly a robust decision-support management tool for vineyard in future.

evolutionary biology↗