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Understanding growth mechanisms in brown algae is a current scientific and economic challenge that can benefit from the modeling of their metabolic networks. The sequencing of the genomes of Saccharina japonica and Cladosiphon okamuranus has provided the necessary data for the reconstruction of Genome–Scale Metabolic Networks (GSMNs). The same in silico method deployed for the GSMN reconstruction of Ectocarpus siliculosus to investigate the metabolic capabilities of these two algae, was used. Integrating metabolic profiling data from the literature, we provided functional GSMNs composed of an average of 2230 metabolites and 3370 reactions. Based on these GSMNs and previously published work, we propose a model for the biosynthetic pathways of the main carotenoids in these two algae. We highlight, on the one hand, the reactions and enzymes that have been preserved through evolution and, on the other hand, the specificities related to brown algae. Our data further indicate that, if abscisic acid is produced by Saccharina japonica, its biosynthesis pathway seems to be different in its final steps from that described in land plants. Thus, our work illustrates the potential of GSMNs reconstructions for formalizing hypotheses that can be further tested using targeted biochemical approaches. [ABSTRACT FROM AUTHOR]

Background: A subgroup of patients with chronic pelvic pain (CPP) exhibit organ sensitization, whose origin and mechanism remains largely unknown. Changes in microbiota composition in pelvic organs have been found to be associated with various pelvic pathological conditions. Therefore, a comprehensive analysis of the gut and genito-urinary microbiota composition and interactions in women with CPP may be key to understanding their involvement in the sensitization processes., Objective: To identify pelvic organ microbiota signatures that are associated with organ hypersensitivity in CPP patients., Study Design: This study involved women with high (S-CPP, n=14) and low (NS-CPP, n=14) pelvic sensitization scores according to the Convergences PP criteria. Pelvic organ sensitivity was assessed by rectal barostat, and noninvasive bladder, muscular and vulvar sensory tests. Quality of life, pelvic symptoms and psychological state were assessed. Using 16S rRNA gene sequencing, the gut, vaginal and urinary microbiota diversity and composition were analyzed and compared between S-CPP and NS-CPP women. Differentially abundant bacterial amplicon sequence variants (ASVs) between groups were associated with clinical characteristics and organ sensitivity. System biology approaches using Weighted Gene Correlation Network Analysis (WGCNA) were used to identify bacterial ASV modules associated with functional and clinical parameters., Results: Pain pressure thresholds were significantly decreased in S-CPP women for the vulva and for the rectum, the bladder and the perineal muscles as compared to NS-CPP. However, pain intensity felt at rectal, muscular and bladder pain thresholds was significantly increased in S-CPP women. After stimulation, S-CPP women presented increased and prolonged pain in perineal muscles and bladder compared to NS-CPP women. Alpha and β-diversities were significantly increased in S-CPP women in vaginal and urinary but not in gut microbiota. Using, differential abundance analysis, we showed that 13 ASVs in the gut, 6 in the vagina and 2 in the bladder were differentially expressed between S-CPP and NS-CPP patients. More specifically, in vaginal microbiota, a significant increase of Streptococcus and Prevotella genera was observed in S-CPP as compared to NS-CPP. A significant increase in Clostridium sensu stricto 1 ASV was observed in urinary microbiota of S-CPP as compared to NS-CPP patients. Next, we found that 4 gut microbiota ASVs (belonging to Akkermansia, Desulfovibrio, Faecalibacterium and CAG-352) were correlated with pain intensity at maximal rectal distension threshold. We also identified an ASV (Blautia) which is increased in NS-CPP as being inversely correlated to several gut sensitization markers. In the vaginal microbiota, the Lactobacillus jensenii ASV was associated with less dysmenorrhea and an increased bladder capacity. Furthermore, we identified two vaginal ASVs belonging to Prevotella which are increased in S-CPP as being associated with dysmenorrhea. Finally, using WGCNA analysis methods, we identified vaginal and urinary tract ASVs modules driven by Peptostreptococcales-Tissierellales Peptoniphilus which were strongly correlated with rectal, muscular and bladder poststimulation pain. We also identified a gut ASVs module driven by Christensenellaceae_R-7 that significantly associated with anxiety, gastro-intestinal symptoms and rectal sensitivity., Conclusions: This work identified specific bacterial signatures of specific pelvic organs and their association with organ sensitization, which are potential therapeutic targets in CPP women., (Copyright © 2025 The Author(s). Published by Elsevier Inc. All rights reserved.)

Flavobacteriia are recognized as key players in the marine carbon cycle, due to their ability to efficiently degrade algal polysaccharides both in the open ocean and in coastal regions. The chemical complexity of algal polysaccharides, their differences between algal groups and variations through time and space, imply that marine flavobacteria have evolved dedicated degradation mechanisms and regulation of their metabolism during interactions with algae. In the present study, we report the first transcriptome-wide gene expression analysis for an alga-associated flavobacterium during polysaccharide degradation. Zobellia galactanivorans Dsij T , originally isolated from a red alga, was grown in minimal medium with either glucose (used as a reference monosaccharide) or one selected algal polysaccharide from brown (alginate, laminarin) or red algae (agar, porphyran, ι- or κ-carrageenan) as sole carbon source. Expression profiles were determined using whole-genome microarrays. Integration of genomic knowledge with the automatic building of a co-expression network allowed the experimental validation of operon-like transcription units. Differential expression analysis revealed large transcriptomic shifts depending on the carbon source. Unexpectedly, transcriptomes shared common signatures when growing on chemically divergent polysaccharides from the same algal phylum. Together with the induction of numerous transcription factors, this hints at complex regulation events that fine-tune the cell behavior during interactions with algal biomass in the marine environment. The results further highlight genes and loci that may participate in polysaccharide utilization, notably encoding Carbohydrate Active enZymes (CAZymes) and glycan binding proteins together with a number of proteins of unknown function. This constitutes a set of candidate genes potentially representing new substrate specificities. By providing an unprecedented view of global transcriptomic responses during polysaccharide utilization in an alga-associated model flavobacterium, this study expands the current knowledge on the functional role of flavobacteria in the marine carbon cycle and on their interactions with algae.