Galactofuranose is a rare form of the well-known galactose sugar, and its occurrence in numerous pathogenic micro-organisms makes the enzymes responsible for its biosynthesis interesting targets. Herein, we review the role of these carbohydrate-related proteins with a special emphasis on the galactofuranosidases we recently characterized as an efficient recombinant biocatalyst.

In the absence of naturally available galactofuranose-specific lectin, we report herein the bioengineering of GalfNeoLect, from the first cloned wild-type galactofuranosidase (Streptomyces sp. strain JHA19), which recognises and binds a single monosaccharide that is only related to nonmammalian species, usually pathogenic microorganisms. We kinetically characterised the GalfNeoLect to confirm attenuation of hydrolytic activity and used competitive inhibition assay, with close structural analogues of Galf, to show that it conserved interaction with its original substrate. We synthetised the bovine serum albumin-based neoglycoprotein (GalfNGP), carrying the multivalent Galf units, as a suitable ligand and high-avidity system for the recognition of GalfNeoLect which we successfully tested directly with the galactomannan spores of Aspergillus brasiliensis (ATCC 16404). Altogether, our results indicate that GalfNeoLect has the necessary versatility and plasticity to be used in both research and diagnostic lectin-based applications.

Nasopharyngeal samples are currently accepted as the standard diagnostic samples for nucleic acid amplification testing and antigenic testing for the SARS-CoV-2 virus. In addition to the diagnostic capacity of SARS-CoV-2-positive crude nasopharyngeal samples, their qualitative potential for direct glycan-specific analysis, in order to uncover unique glycol profiles, was assessed. In this study we provide glycan characterization of SARS-CoV-2-positive and -negative nasopharyngeal samples directly from lectin interactions. Although with limited throughput, this study evaluated the clinical sensitivity and specificity of the GLYcoPROFILE^® technology platformon45crude nasopharyngeal samples collected between November 2020 and April 2022. Each GLYcoPROFILE^® of 39 SARS-CoV-2-positive samples was compared toglycoprofiling on a panel of 10 selected lectins and the results were paralleled with SARS-CoV-2-negative samples’ results. The GLYcoPROFILE^® showed a clear distinction between positive and negative samples with WFA, GSL-II, PHA-L (GlcNAc-specific) and BPA (GalNAc-specific) highlighted as relevant lectins in SARS-CoV-2-positive samples. In addition, a significant, positive statistical correlation was found for these lectins (p < 0.01).

This study assessed the potential of Oleaster leaves as a valuable cosmetic ingredient by comparing aqueous and hydroalcoholic ultrasound-assisted extracts of Oleaster leaves to those of the Olive tree. The hydroalcoholic Oleaster leaf extract showed a higher content in phenolic and flavonoid compounds, with an oleuropein and verbascoside content of 58 mg/g of dry leaves and 3.2 mg/g of dry leaves, respectively. To refine the comparison of their molecular composition, the extracts were analyzed using UHPLC-HRMS/MS. About twenty compounds, including secoiridoids, flavonoids and triterpenic acid derivatives, were annotated in both extracts, demonstrating their similarity. DPPH, CUPRAC and enzymatic SOD assays showed a good antioxidant activity with high inhibition (60–90%) for both Oleaster and Olive tree leaf extracts. The hydroalcoholic extracts at 62.5 µg/mL also exhibited 60–80% of protection against reactive oxygen species (ROS) in H₂O₂-stressed HaCaT cells, confirming this antioxidant capacity without demonstrating a severe cytotoxicity, which remained below 40%. The anti-inflammatory potential of the extracts was also demonstrated using COX-2 inhibition, which was around 70%, and by measuring the concentration of IL-8 in HaCaT cells under pro-inflammatory conditions, which decreased in the presence of extracts at a concentration of 50 pg/mL, similar to that observed for the positive control. Thus, the hydroalcoholic ultrasound extract of Oleaster leaves demonstrated its high potential to develop sustainable and active cosmetic ingredients.