Plant cell wall composition modulates the gut microbiota and metabolites in in-vitro fermentation.

This research investigated the effect of different types of plant cell wall fibres, including cereal (i.e., barley, sorghum, and rice), legume (i.e., pea, faba bean, and mung bean), and tuber (potato, sweet potato, and yam) cell wall fibres on in vitro faecal fermentation profiles and gut microbiota composition. The cell wall composition, specifically the content of lignin and pectin, was found to have a significant influence on the gut microbiota and fermentation outcomes. Compared with type I cell walls (legume and tuber) which have high pectin content, the type II cell walls (cereal) which are high in lignin but low in pectin had a lower fermentation rates and less short-chain fatty acid production. The redundancy analysis showed samples with similar fibre composition and fermentation profiles clustered together, and the principal coordinate analysis revealed separation among different types of cell walls and closer proximity among the same cell wall types. These findings emphasize the importance of cell wall composition in shaping the microbial community during fermentation and contribute to a better understanding of the relationship between plant cell walls and gut health. This research has practical implications for the development of functional foods and dietary interventions.

Cell Wall Composition Heterogeneity between Single Cells in Aspergillus fumigatus Leads to Heterogeneous Behavior during Antifungal Treatment and Phagocytosis.

Aspergillus fumigatus can cause a variety of lung diseases in immunocompromised patients, including life-threatening invasive aspergillosis. There are only three main classes of antifungal drugs currently used to treat aspergillosis, and antifungal resistance is increasing. Experimental results in fungal biology research are usually obtained as average measurements across whole populations while ignoring what is happening at the single cell level. In this study, we show that conidia with the same genetic background in the same cell population at a similar developmental stage show heterogeneity in their cell wall labeling at the single cell level. We present a rigorous statistical method, newly applied to quantify the level of cell heterogeneity, which allows for direct comparison of the heterogeneity observed between treatments. We show the extent of cell wall labeling heterogeneity in dormant conidia and how the level of heterogeneity changes during germination. The degree of heterogeneity is influenced by deletions of cell wall synthesizing genes and environmental conditions, including medium composition, method of inoculation, age of conidia, and the presence of antifungals. This heterogeneity results in subpopulations of germinating conidia with heterogeneous fitness to the antifungal caspofungin, which targets cell wall synthesis and heterogeneous sensitivity of dormant conidia to phagocytosis by macrophages.IMPORTANCE The fungus Aspergillus fumigatus can cause invasive lung diseases in immunocompromised patients resulting in high mortality. Treatment using antifungal compounds is often unsuccessful. Average population measurements hide what is happening at the individual cell level. We set out to test what impact individual differences between the cell walls of fungal conidia have on their behavior. We show that a population of cells having the same genetic background gives rise to subpopulations of cells that exhibit distinct behavior (phenotypic heterogeneity). This cell heterogeneity is dependent on the strain type, gene deletions, cell age, and environmental conditions. By looking at the individual cell level, we discovered subpopulations of cells that show differential fitness during antifungal treatment and uptake by immune cells.

Identification and analysis of cell wall glycan epitopes and polyphenol oxidase in pawpaw (Asimina triloba [L.] Dunal) fruit pulp as affected by high pressure processing and refrigerated storage.

This research explores the cell wall composition and polyphenol oxidase activity of two pawpaw (Asimina triloba) fruit varieties, Susquehanna and Green River Belle, that were subjected to high pressure processing and 45 days of refrigerated storage. We hypothesize that high pressure processing may inhibit enzymatic action responsible for pawpaw's deleterious postharvest tissue softening and browning. Glycome profiling uses mAb groupings that recognize 19 groups of glycan epitopes present in most major classes of cell wall glycans and was used to determine cell wall composition. Results show that both varieties have typical type I primary cell walls of flowering dicots. However, differences in the fine cell wall structure between the varieties can be inferred and the varieties behaved differently during refrigerated storage, likely indicating of a difference in cell wall-modifying enzymes present in the primary cell walls. High pressure processing treatment does not seem to be effective at eliminating polyphenol oxidase activity.

Unexpected features of exponentially growing Tobacco Bright Yellow-2 cell suspension culture in relation to excreted extracellular polysaccharides and cell wall composition.

This article presents a new insight about TBY-2 cells; from extracellular polysaccharides secretion to cell wall composition during cell suspension culture. In the medium of cells taken 2 days after dilution (end of lag phase), a two unit pH decrease from 5.38 to 3.45 was observed and linked to a high uronic acid (UA) amount secretion (47.8%) while, in 4 and 7 day-old spent media, pH increased and UA amounts decreased 35.6 and 42.3% UA, respectively. To attain deeper knowledge of the putative link between extracellular polysaccharide excretion and cell wall composition, we determined cell wall UA and neutral sugar composition of cells from D2 to D12 cultures. While cell walls from D2 and D3 cells contained a large amount of uronic acid (twice as much as the other analysed cell walls), similar amounts of neutral sugar were detected in cells from lag to end of exponential phase cells suggesting an enriched pectin network in young cultures. Indeed, monosaccharide composition analysis leads to an estimated percentage of pectins of 56% for D3 cell wall against 45% D7 cell walls indicating that the cells at the mid-exponential growth phase re-organized their cell wall linked to a decrease in secreted UA that finally led to a stabilization of the spent medium pH to 5.4. In conclusion, TBY-2 cell suspension from lag to stationary phase showed cell wall remodeling that could be of interest in drug interaction and internalization study.

Cell wall composition profiling of parasitic giant dodder (Cuscuta reflexa) and its hosts: a priori differences and induced changes.

Host plant penetration is the gateway to survival for holoparasitic Cuscuta and requires host cell wall degradation. Compositional differences of cell walls may explain why some hosts are amenable to such degradation while others can resist infection. Antibody-based techniques for comprehensive profiling of cell wall epitopes and cell wall-modifying enzymes were applied to several susceptible hosts and a resistant host of Cuscuta reflexa and to the parasite itself. Infected tissue of Pelargonium zonale contained high concentrations of de-esterified homogalacturonans in the cell walls, particularly adjacent to the parasite's haustoria. High pectinolytic activity in haustorial extracts and high expression levels of pectate lyase genes suggest that the parasite contributes directly to wall remodeling. Mannan and xylan concentrations were low in P. zonale and in five susceptible tomato introgression lines, but high in the resistant Solanum lycopersicum cv M82, and in C. reflexa itself. Knowledge of the composition of resistant host cell walls and the parasite's own cell walls is useful in developing strategies to prevent infection by parasitic plants.

Relationship between skin cell wall composition and anthocyanin extractability of Vitis vinifera L. cv. Tempranillo at different grape ripeness degree.

The relationship between cell wall composition and extractability of anthocyanins from red grape skins was assessed in Tempranillo grape samples harvested at three stages of ripening (pre-harvest, harvest and over-ripening) and three different contents of soluble solids (22, 24 and 26 °Brix) within each stage. Cell wall material was isolated and analysed in order to determine cellulose, lignin, non-cellulosic polysaccharides, protein, total polyphenols index and the degree of esterification of pectins. Results showed the influence of ripeness degree and contents of soluble solids on cell wall composition. Furthermore, principal components analysis was applied to the obtained data set in order to establish relationships between cell wall composition and extractability of anthocyanins. Total insoluble material exhibits the biggest opposition to anthocyanin extraction, while the highest amounts of cellulose, rhamnogalacturonans-II and polyphenols were positively correlated with anthocyanin extraction. Moreover, multiple linear regression was performed to assess the influence of the cell wall composition on the extraction of anthocyanin compounds. A model connecting cell wall composition and anthocyanin extractabilities was built, explaining 96.2% of the observed variability.