Campos, N. | bioRxiv Science

bioRxiv2021

From fruit growth to ripening in plantain: a careful balance between carbohydrate synthesis and breakdown

We investigated the fruit development in two plantain banana cultivars from two weeks after bunch emergence till twelve weeks through high-throughput proteomics, major metabolite quantification and metabolic flux analyses. We give for the first time an insight at early stages of starch synthesis and breakdown. Starch and sugar synthesis and breakdown are processes that take place simultaneously. During the first eight to ten weeks the balance between synthesis and breakdown is clearly in favour of sugar breakdown and a net starch synthesis occurs. During this period, plantain fruit accumulates up to 48% of starch. The initiation of the ripening process is accompanied with a shift in balance towards net starch breakdown. The key enzymes related to this are phosphoglucan water dikinase (PWD), phosphoglucan phosphatase, -1,6-glucosidase starch debranching enzyme (DBE), alpha glucan phosphorylase (PHS) and 4-alpha glucanotransferase disproportioning enzyme (DPE). The highest correlations with sucrose have been observed for PHS and DPE. There is also a significant correlation between the enzymes involved in ethylene biosynthesis, starch breakdown, pulp softening and ascorbate biosynthesis. The faster ending of maturation and starting of ripening in the Agbagba cultivar are linked to the key enzymes 1-aminocyclopropane-1-carboxylate oxidase and DPE. This knowledge of the mechanisms that regulate starch and sugar metabolisms during maturation and ripening is fundamental to determine the harvest moment, reduce postharvest losses and improve final product quality of breeding programs.

plant biology↗

bioRxiv2019

Targeting the Long Non-Coding RNA LINC00599-205 splicing by novel candidate drug ABX464 to produce anti-inflammatory MicroRNA miR-124

Many nascent long non-coding RNAs have received considerable attention in recent years because of their major regulatory roles in gene expression and signaling pathways at various levels. Indeed long non-coding RNAs undergo the same maturation steps as pre-mRNAs of proteincoding genes, but they are less efficiently spliced and polyadenylated in comparison to them. Here we focus on a specific human long non-coding RNA and we show the activity of a new candidate drug that potentially affect its splicing and generate an anti-HIV and anti-inflammatory effects driven by upregulation of microRNA biogenesis. To investigate this activity we combine the use of capture sequencing technology and an ab initio transcript assembly on cells from six healthy individuals. The sequencing depth of capture sequencing permitted us to assemble transcripts exhibiting a complex array of splicing patterns. In essence, we revealed that splicing of the long non-coding RNA is activated by the drug whereas this splicing was not present in untreated samples.

immunology↗