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The permeabilized cells of two Pantoea anthophila strains (BI 55.2 and BI 69.1) were evaluated for galactosylation of phenolic compounds with different molecular structure (gallic acid, caffeic acid, catechin, phlorizin, puerarin and mangiferin), the highest conversion was observed on puerarin (36.5 ± 8.4 and 53.3 ± 7.1), followed by phlorizin (33.5 ± 4.6 and 41.8 ± 0.4) and caffeic acid (21.4 ± 0.05 and 32.5 ± 0.5), respectively, no reaction was observed on mangiferin. They also exhibited a high catalytic promiscuity for most of the phenolic compounds (3 to 7 different galactosides). BI 69.1 was selected for a further kinetic characterization on phlorizin and puerarin as acceptors, elongation of the galactosyl change was observed, the mass spectrometry determined by UPLC-ESI-Qtof-MS showed the synthesis of digalactosides (759.1 and 739.08 m /z ) from monogalactosides as starters (597.13 and 577.12 m /z ) for phlorizin and puerarin, respectively. The major phenolic galactoside was purified and the molecular structure was elucidated by NMR, corresponding to a β-D-(1 → 6) puerarin monogalctoside. Key points • Permeabilized cells efficiently galactosylate diverse phenolic substrates • High catalytic promiscuity observed with formation of multiple galactosides • NMR confirmed a β-D-(1→6) monogalactoside structure derived from puerarin Graphical Abstract

Galectin-3 is a carbohydrate binding protein which has important roles in cancer and immunity. Potent galectin-3 inhibitors have been synthesized, for experimental purposes and potential clinical use. As galectin-3 is implicated in both intra- and extracellular activities, permeability of galectin-3 inhibitors is an important parameter determining biological effects. We compared the cellular uptake of galectin-3 inhibitors and their potency in the intracellular or extracellular space. The inhibitors differed in their polar surface area (PSA), but had similar affinities for galectin-3. Using a well-established permeability assay, we confirmed that the uptake was significantly higher for the inhibitor with the lowest PSA, as expected. To analyze intracellular activity of the inhibitors, we developed a novel assay based on galectin-3 accumulation around damaged intracellular vesicles. The results show striking differences between the inhibitors intracellular potency, correlating with their PSAs. To test extracellular activity of the inhibitors, we analyzed their potency to block binding of galectin-3 to cell surfaces. All inhibitors were equally able to block galectin-3 binding to cells and this was proportional to their affinity for galectin-3. These inhibitors may serve as useful tools in exploring biological roles of galectin-3 and may further our understanding of intracellular versus extracellular roles of galectin-3.

Galectins are a phylogenetically conserved family of soluble β-galactoside binding proteins. There are 16 different of galectins, each with a specific function determined by its distinct distribution and spatial structure. Galectin-13, galectin-14, and galectin-16 are distinct from other galectin members in that they are primarily found in placental tissue. These galectins, also referred to as placental galectins, play critical roles in regulating pregnancy-associated processes, such as placenta formation and maternal immune tolerance to the embedded embryo. The unique structural characteristics and the inability to bind lactose of placental galectins have recently received significant attention. This review primarily examines the novel structural features of placental galectins, which distinguish them from the classic galectins. Furthermore, it explores the correlation between these structural features and the loss of β-galactoside binding ability. In addition, the newly discovered functions of placental galectins in recent years are also summarized in our review. A detailed understanding of the roles of placental galectins may contribute to the discovery of new mechanisms causing numerous pregnancy diseases and enable the development of new diagnostic and therapeutic strategies for the treatment of these diseases, ultimately benefiting the health of mothers and offspring. Summary Sentence In conclusion, this review provides a summary of the novel structural features and biological roles of placental galectins, providing important support for the design of therapeutic interventions targeting placental galectins in reproductive medicine. Graphical Abstract

Normal cells can permanently lose the ability to proliferate when challenged by potentially oncogenic stress, a process termed cellular senescence. Senescence-associated beta-galactosidase (SA-βgal) activity, detectable at pH 6.0, permits the identification of senescent cells in culture and mammalian tissues. Here we describe first a cytochemical protocol suitable for the histochemical detection of individual senescent cells both in culture and tissue biopsies. The second method is based on the alkalinization of lysosomes, followed by the use of 5-dodecanoylaminofluorescein di-β- D -galactopyranoside (C 12 FDG), a fluorogenic substrate for βgal activity. The cytochemical method takes about 30 min to execute, and several hours to a day to develop and score. The fluorescence methods take between 4 and 8 h to execute and can be scored in a single day. The cytochemical method is applicable to tissue sections and requires simple reagents and equipment. The fluorescence-based methods have the advantages of being more quantitative and sensitive.

3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell proliferation assay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

Abstract Common enteric viruses rely on sugars mediated by the galactoside 2-alpha-L-fucosyltransferase 2 (FUT2) enzyme to infect host cells. Analyzing 4,343 ancient genomes, we map a premature stop codon in FUT2, which was introduced into Europe by migrating Anatolian farmers ∼6000 BC and provide evidence for positive selection. Using data from ∼700,000 present-day individuals, we confirm its protective effect against viral gastroenteritis. Experiments with intestinal organoids reveal that only homozygous carriers are protected against noroviruses and rotaviruses but not sapovirus. Our rotavirus findings resolve a long-standing contradiction between epidemiological data and experiments. Contrary to previous reports, we find no association between FUT2 loss of function and Helicobacter pylori infection. However, carriers exhibit an increased risk of gastric ulcers and gallbladder disease, associations replicated with an independent loss-of-function variant in East Asia. These findings suggest that the transition to agriculture and increased pathogen exposure drove positive selection of this allele.

The kinetics of anthocyanin metabolism was investigated in a human feeding trial. Volunteers (n 12) consumed purple carrots containing five anthocyanin forms: cyanidin-3-(xylose-glucose-galactoside), cyanidin-3-(xylose-galactoside), cyanidin-3-(xylose-sinapoyl-glucose-galactoside), cyanidin-3-(xylose-feruloyl-glucose-galactoside) and cyanidin-3-(xylose-coumuroyl-glucose-galactoside). The purple carrots were served as three different treatments in a crossover design with a 3-week washout between treatments. Purple carrot treatments were 250 g raw carrots, 250 g cooked carrots and 500 g cooked carrots. Serial blood and urine samples were collected for 8 and 24 h after the dose, respectively, and analysed for anthocyanins. Of the anthocyanin forms ingested, four were detected in plasma and urine: cyanidin-3-(xylose-glucose-galactoside), cyanidin-3-(xylose-galactoside), cyanidin-3-(xylose-sinapoyl-glucose-galactoside) and cyanidin-3-(xylose-feruloyl-glucose-galactoside). The time courses of plasma and urine anthocyanin contents were evaluated with compartmental modelling. Results showed that absorption, gastrointestinal transit and plasma elimination are dependent on anthocyanin structure. Absorption efficiencies of acylated compounds (cyanidin-3-(xylose-sinapoyl-glucose-galactoside) and cyanidin-3-(xylose-feruloyl-glucose-galactoside)) were less than those for non-acylated anthocyanins (cyanidin-3-(xylose-glucose-galactoside) and cyanidin-3-(xylose-galactoside)). The acylated anthocyanins exhibited a shorter half-life for gastrointestinal absorption than the non-acylated anthocyanins. Fractional elimination of non-acylated compounds was slower than that for acylated anthocyanins. These results provide the first information about the kinetics of individual anthocyanins in human beings.

Cyanidin, peonidin and cyanidin-3-galactoside are the common anthocyanins with a variety of biological activities. Tyrosinase is a speed-limiting enzyme associated with melanin production. The inhibition of tyrosinase activity can prevent melanin disease while contributing to whitening. The interaction behaviors of the three anthocyanins against tyrosinase have been discussed in this paper. Cyanidin has strongest inhibitory effect on tyrosinase, and then peonidin, cyanidin-3-galactoside. Furthermore, the inhibition of tyrosinase by the three anthocyanins is mixed modes. The three anthocyanins can induce the static fluorescence quenching of tyrosinase. Cyanidin exhibits strongest binding affinity on tyrosinase, and then peonidin, cyanidin-3-galactoside based on K a values obtain by fluorescence analysis. The binding of all anthocyanin to tyrosinase induce its conformation changes. According to molecular docking and fluorescence studies, they bind to tyrosinase by hydrogen bond and van der Waals force. In addition, the optimal modes of the three anthocyanins with tyrosinase are predicated by molecular docking. This work emphasizes that cyanidin, peonidin and cyanidin-3-galactoside may be potential drugs for the treatment of diseases caused by melanin.

The biological process, 3-O-galactosylation, is important in plant cells. To understand the mechanism of the reduction of flavonol antioxidative activity by 3-O-galactosylation, myricetin-3-O-galactoside (M3OGa) and myricetin aglycone were each incubated with 2 mol α,α-diphenyl-β-picrylhydrazyl radical (DPPH•) and subsequently comparatively analyzed for radical adduct formation (RAF) products using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS) technology. The analyses revealed that M3OGa afforded an M3OGa–DPPH adduct (m/z 873.1573) and an M3OGa–M3OGa dimer (m/z 958.1620). Similarly, myricetin yielded a myricetin–DPPH adduct (m/z 711.1039) and a myricetin–myricetin dimer (m/z 634.0544). Subsequently, M3OGa and myricetin were compared using three redox-dependent antioxidant analyses, including DPPH•-trapping analysis, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-trapping analysis, and •O2 inhibition analysis. In the three analyses, M3OGa always possessed higher IC50 values than those of myricetin. Conclusively, M3OGa and its myricetin aglycone could trap the free radical via a chain reaction comprising of a propagation step and a termination step. At the propagation step, both M3OGa and myricetin could trap radicals through redox-dependent antioxidant pathways. The 3-O-galactosylation process, however, could limit these pathways; thus, M3OGa is an inferior antioxidant compared to its myricetin aglycone. Nevertheless, 3-O-galactosylation has a negligible effect on the termination step. This 3-O-galactosylation effect has provided novel evidence that the difference in the antioxidative activities of phytophenols exists at the propagation step rather than the termination step.

This study analyzed the coupling between cooking and the subsequent fermentation in fermented legume seed processing. It is, to our knowledge, the first to evaluate how cooking time modulates fermentation. Soybeans were cooked for 10 and 30 min before being fermented with Rhizopus oligosporus. α‐Galactosides, phytic acid, phytase activity, trypsin inhibitors, lectins, and isoflavones were determined during cooking and fermentation. Diffusion into the cooking water was also characterized, and fungal fermentation results were compared with a non‐inoculated treatment. Fermentation of seeds cooked for 10 min resulted in slower mycelial growth and needed to be prolonged to reach a reduction in α‐galactosides and an increase in aglycones comparable to those obtained for seeds cooked for 30 min. Additionally, fermentation with the fungal strain had a low impact on phytic acid in seeds cooked for either 10 or 30 min. The combination of 10‐min cooking and 72‐h fermentation of soybeans resulted in a 90% reduction in total α‐galactosides, a 17% reduction in phytic acid, and an increase in aglycones to 40 mg/100 g DM (dry matter), whereas the combination of 30‐min cooking and 48‐h fermentation of soybeans resulted in an 84% reduction in total α‐galactosides, an 18% reduction in phytic acid, and an increase in aglycones to 39 mg/100 g DM. Trypsin inhibitors and lectins remained present in seeds cooked for 10 min, and R. oligosporus could not hydrolyze all the trypsin inhibitors and had no effect on the remaining lectins. This study provides new insights for the fermented legumes food processing sector.