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A small library of 6-substituted syringyl model compounds with aliphatic, carboxylic, phenylic, benzylic alcohols and brominated substituents were prepared. The influence of the substituents on the chemical shifts of the compounds was analyzed. All of model compounds showed a characteristic increase in the 13C NMR chemical shift of the methoxy group vicinal to the substitution. This 13C NMR peak and its corresponding correlation peak in HSQC could potentially be used to identify 6-condensation in syringylic lignin samples.

In Betula celtiberica (Iberian white birch) stemwood, the content and composition of lipophilic and hydrophilic extractives were determined; these have not been reported previously in this species. The total gravimetric amount of extractives was 2.2% of dry wood, of which lipophilic extractives accounted for 0.39% and hydrophilic extractives 1.84% (determined by gas chromatography–flame ionisation detection [GC–FID]). The lipophilic extract contained mainly triterpenoids and steroids. The hydrophilic extract (acetone–water 95:5 v v−1) contained mainly sugars, compounds not eluting on GC, and a large number of unidentified compounds, which accounted for 0.87% of dry wood and dominated the extract. The compounds were isolated from the extract by silica column chromatography and further purified. GC–electron impact (EI)-MS of the silylated compounds showed characteristic mass fragments that suggested them to be diarylheptanoids (DAHs). This is an interesting compound group, as many of them have shown a large variety of beneficial biological effects. Of over 80 detected DAHs, the exact mass of 17 compounds was determined by electrospray ionisation-quadrupole-time-of-flight (ESI-QTOF)-MS, and of these, the structure of 11 compounds was elucidated by nuclear magnetic resonance (NMR). One was a meta,para-bridged diphenylether and 10 were meta,meta-bridged biphenyls, of which one, 3,8,9,17-tetrahydroxy-[7,0]-metacyclophane, has not been described previously. Because of low concentrations, 21 DAHs were only tentatively identified, and of these, as many as 17 seem to be previously undescribed compounds.

Thermal transformations of polyphenols from the lignan and stilbene families were investigated at temperatures ranging from 200 °C to 250 °C, in polyethylene glycol (PEG-400), dimethylformamide (DMF) and in sunflower oil (SO). The polyphenols showed varying degrees of thermal stabilities and in some cases intramolecular transformations were observed. The formed products were isolated and characterized. Oligomerization of the polyphenols at thermo-oxidative conditions was also investigated. Finally, the antioxidative activity of the polyphenols against thermo-oxidative degradation α-linoleic acid was investigated at 200 °C. The results suggested that the studied substrates retained their antioxidative properties at elevated temperatures, with stilbenes showing most efficient protection against thermo-oxidative degradation of polyunsaturated fatty acids.

Streptococcus suis is part of the pig commensal microbiome but strains can also be pathogenic, causing pneumonia and meningitis in pigs as well as zoonotic meningitis. According to genomic analysis, S. suis is divided into asymptomatic carriage, respiratory and systemic strains with distinct genomic signatures. Because the strategies to target pathogenic S. suis are limited, new therapeutic approaches are needed. The virulence factor S. suis adhesin P (SadP) recognizes the galabiose Gal alpha 1-4Gal-oligosaccharide. Based on its oligosaccharide fine specificity, SadP can be divided into subtypes P-N and P-O. We show here that subtype P-N is distributed in the systemic strains causing meningitis, whereas type P-O is found in asymptomatic carriage and respiratory strains. Both types of SadP are shown to predominantly bind to pig lung globotriaosylceramide (Gb3). However, SadP adhesin from systemic subtype P-N strains also binds to globotetraosylceramide (Gb4). Mutagenesis studies of the galabiose-binding domain of type P-N SadP adhesin showed that the amino acid asparagine 285, which is replaced by an aspartate residue in type P-O SadP, was required for binding to Gb4 and, strikingly, was also required for interaction with the glycomimetic inhibitor phenylurea-galabiose. Molecular dynamics simulations provided insight into the role of Asn-285 for Gb4 and phenylurea-galabiose binding, suggesting additional hydrogen bonding to terminal GalNAc of Gb4 and the urea group. Thus, the Asn-285-mediated molecular mechanism of type P-N SadP binding to Gb4 could be used to selectively target S. suis in systemic disease without interfering with commensal strains, opening up new avenues for interventional strategies against this pathogen.

Furfural oxidation with hydrogen peroxide was performed using sulfated zirconia as an acid catalyst within the temperature range of 40–90 °C. The catalytic behavior of sulfated zirconia due to its ...

Improved methods for one-pot propargylation and Claisen rearrangement have been devised for natural lignans – matairesinol and α-conidendrin. The rearrangement was regiospecific, yielding only 2-methylbenzofuran derivatives.

Actinomycetes are important producers of pharmaceuticals and industrial enzymes. However, wild type strains require laborious development prior to industrial usage. Here we present a generally applicable reporter-guided metabolic engineering tool based on random mutagenesis, selective pressure, and single-cell sorting. We developed fluorescence-activated cell sorting (FACS) methodology capable of reproducibly identifying high-performing individual cells from a mutant population directly from liquid cultures. Genome-mining based drug discovery is a promising source of bioactive compounds, which is complicated by the observation that target metabolic pathways may be silent under laboratory conditions. We demonstrate our technology for drug discovery by activating a silent mutaxanthene metabolic pathway in Amycolatopsis. We apply the method for industrial strain development and increase mutaxanthene yields 9-fold to 99 mg l−1 in a second round of mutant selection. Actinomycetes are an important source of catabolic enzymes, where product yields determine industrial viability. We demonstrate 5-fold yield improvement with an industrial cholesterol oxidase ChoD producer Streptomyces lavendulae to 20.4 U g−1 in three rounds. Strain development is traditionally followed by production medium optimization, which is a time-consuming multi-parameter problem that may require hard to source ingredients. Ultra-high throughput screening allowed us to circumvent medium optimization and we identified high ChoD yield production strains directly from mutant libraries grown under preset culture conditions. In summary, the ability to screen tens of millions of mutants in a single cell format offers broad applicability for metabolic engineering of actinomycetes for activation of silent metabolic pathways and to increase yields of proteins and natural products.

Funding Information: V.G. and P.V. acknowledge Academy of Finland’s Project No. 308931. J.J.V.D. and M.Ö. acknowledge Academy of Finland’s Flagship Programme under Project Nos. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES). M.Y. acknowledges Academy of Finland’s Flagship Programme under Project No. 337430 (Gene, Cell and Nano Therapy Competence Cluster for the Treatment of Chronic Diseases, GeneCellNano). Publisher Copyright: © 2021 The Authors. Published by American Chemical Society. Bingel cyclopropanation between Buckminster fullerene and a heteroarmed malonate was utilized to produce a hexakis-functionalized C60 core, with azide and tetrazine units. This orthogonally bifunctional C60 scaffold can be selectively one-pot functionalized by two pericyclic click reactions, that is, inverse electron-demand Diels-Alder and azide-alkyne cycloaddition, which with appropriate ligands (monosaccharides, a peptide and oligonucleotides tested) allows one to control the assembly of heteroantennary bioconjugates.

International audience

The carboxymethylation of cinnamylalcohol with dimethyl carbonate was performed using low-cost catalysts obtained from desulfurization slag. Processing of steel slag performed by different techniques was resulted in a wide range of the catalysts with different morphological and structural properties. Catalytic evaluation of the slag catalysts illustrated diversity of the obtained results strongly dependent on the surface area, crystal morphology and basicity. Catalytic materials demonstrated high variability of the conversion (8–85%) exhibiting similar selectivity to the desired product – cinnamyl methyl carbonate (ca. 80%). A significant impact of ultrasonication on catalytic activity was observed. Comparison of the synthesized samples with commercial basic materials illustrated competitive ability of the slag catalysts. Based on the results of catalytic evaluation and product analysis the reaction network was proposed and verified by thermodynamic analysis. A kinetic model was developed to describe concentration dependencies in carboxymethylation.

An azide-functionalized 12-armed Buckminster fullerene has been monosubstituted in organic media with a substoichiometric amount of cyclooctyne-modified oligonucleotides. Exposing the intermediate products then to the same reaction (i.e., strain-promoted alkyne-azide cycloaddition, SPAAC) with an excess of slightly different oligonucleotide constituents in an aqueous medium yields molecularly defined monofunctionalized spherical nucleic acids (SNAs). This procedure offers a controlled synthesis scheme in which one oligonucleotide arm can be functionalized with labels or other conjugate groups (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, DOTA, and Alexa-488 demonstrated), whereas the rest of the 11 arms can be left unmodified or modified by other conjugate groups in order to decorate the SNAs' outer sphere. Extra attention has been paid to the homogeneity and authenticity of the C60-azide scaffold used for the assembly of full-armed SNAs. publishedVersion

The main aim of this study was to chemically characterise the polymeric fraction of birch pulp extractives. We showed that 70–96% of the material in extracts of fully bleached birch kraft elemental chlorine-free (ECF) pulp from three Finnish mills consists of compounds that are undetectable by conventional gas chromatography (GC) analysis, i.e. high-molar mass (HM) material. There were small variations in the extractive content and composition between the three mills, but the overall trend was the same. The HM material was present mainly in the acetone extracts, and the molar mass was shown to range between ca. 1000 and 10 000 Da. Alkaline hydrolysis of the hexane and acetone extracts released fatty acids (FAs) especially, but also sterols and triterpenoids. The dominating FAs were palmitic and stearic acids. Pyrolysis and thermally assisted hydrolysis and methylation (THM)-GC-mass spectrometry (MS) analyses confirmed that the HM material consists mainly of FA units, and additionally of sterol, triterpenoid and aromatic units. Nuclear magnetic resonance (NMR) analysis further confirmed the presence of FAs containing aromatic groups, but also glycerol units. The FA chains seemed to be linked to each other by ester linkages mainly, although ether linkages were also present. The FA oligomers and polymers may have a suberin-like structure.

The amount of hydroxyl groups is a crucial parameter when characterizing lignin as a raw material and when developing lignin-based applications. Currently, the most common method used for quantitative hydroxyl group determination is 31P nuclear magnetic resonance (NMR) spectroscopy after phosphitylation of the hydroxyl groups. The method relies on an internal standard for the quantification. The NMR signals of the internal standard have been shown to either overlap with signals from the lignin or to have poor stability due to degradation of the internal standard. To overcome these drawbacks, we have used PULCON (pulse length-based concentration determination) for the quantification of phosphitylated lignin. The method is based on the fact that the product of the intensity of an NMR signal and the length of the 90° pulse is directly proportional to the concentration of the sample. We conclude that the PULCON method could be used for hydroxyl group determination of lignin, and the results obtained are compa...

International audience; Tall oil fatty acids (TOFA) are a byproduct from the Kraft pulping process, and they represent a renewable and inexpensive alternative with high potential as a renewable feedstock. Epoxidized TOFA have great potential as chemical intermediates. Epoxidation of oleic acid, TOFA, and distilled tall oil (DTO) was conducted in an isothermal batch reactor with in situ-formed peracetic acid using hydrogen peroxide as the reactant and acetic acid as the reaction carrier. Amberlite IR-120 was used as the solid heterogeneous catalyst. The catalyst loading effect, the reactant ratios, the reaction temperature (40–70 °C), and the influence of microwave irradiation on epoxidation and ring opening were studied. The application of microwave irradiation resulted in an improvement of the epoxidation rate in the absence of the catalyst. Lower product yields were obtained for the epoxidation of DTO than for TOFA because of the higher viscosity and high content of rosin acids which presumably promoted ring opening reactions. At higher temperatures, the selectivity to oxirane decayed due to ring opening. Titration analysis and NMR analysis confirmed that microwave irradiation induces the ring opening reactions for TOFA epoxidation, and it accelerates this process for DTO. The rapid nature of the microwave heating might have unchained a series of ring opening reactions between neighboring oxirane groups and with the nucleophilic agents in the reaction mixture.

Streptococcus suisis part of the pig commensal microbiome and a major pathogen causing pneumonia and meningitis in pigs and occasionally also zoonotic meningitis. According to genomic analysis,S. suisis divided into asymptomatic carriage, respiratory and systemic strains with distinct genomic signatures. The virulence factorS. suisadhesin P (SadP) recognizes the galabiose Galα1–4Gal-oligosaccharide. Based on its oligosaccharide fine specificity, SadP can be divided into subtypes PNand PO. We show here that subtype PNis distributed in the systemic strains that cause meningitis, whereas type POis found in asymptomatic carriage and respiratory strains. Both types of SadP are shown to predominantly bind to pig lung globotriaosylceramide (Gb3). However, SadP adhesin from systemic subtype PNstrain also binds to globotetraosylceramide (Gb4). Mutagenesis studies of the galabiose-binding domain of type PNSadP adhesin showed that the amino acid asparagine-285, which is replaced by an aspartate residue in type Po SadP, was required for binding to Gb4 and, strikingly, it was also required for interaction with the glycomimetic inhibitor phenylurea-galabiose. Molecular dynamics simulations provided further insight into the role of Asn-285 for Gb4 and phenylurea-galabiose binding, suggesting additional hydrogen bonding to terminal GalNAc of Gb4 and urea-group. Thus, the Asn-285-mediated molecular mechanism of type PNSadP binding to Gb4 could be used as a candidate to selectively targetS. suisin invasive systemic disease without interfering with commensal strains, which may open up new venues for developing intervention strategies against this pathogen.

Acetylated oligosaccharides are common in nature. While they are involved in several biochemical and biological processes, the role of the acetyl groups and the complexity of their migration has largely gone unnoticed. In this work, by combination of organic synthesis, NMR spectroscopy and quantum chemical modeling, we show that acetyl group migration is a much more complex phenomenon than previously known. By use of synthetic oligomannoside model compounds, we demonstrate, for the first time, that the migration of acetyl groups in oligosaccharides and polysaccharides may not be limited to transfer within a single monosaccharide moiety, but may also involve migration over a glycosidic bond between two different saccharide units. The observed phenomenon is not only interesting from the chemical point of view, but it also raises new questions about the potential biological role of acylated carbohydrates in nature.

[EN] Reductive amination of cyclohexanone with benzylamine was investigated at 100 °C under 30 bar hydrogen in toluene with five different gold catalysts prepared by deposition–precipitation method and supported on TiO, LaO/TiO, CeO/TiO, LaO and CeO. Size of metallic gold varied in the range of 2.6–3.6 nm. The best catalysts in reductive amination of cyclohexanone with benzylamine were 4 wt% Au/TiO and 4 wt% Au/CeO/TiO giving 72% and 79% yield of the desired amine. The most acidic and basic catalysts were also unselective and exhibited low activity towards imine hydrogenation. The best catalyst 4 wt% Au/CeO/TiO gave in reductive amination of propiophenone 56% selectivity to the corresponding amine at 20% conversion in 5 h. Graphical Abstract: [Figure not available: see fulltext.], Open access funding provided by Abo Akademi University (ABO). The research is funded from Tomsk Polytechnic University Competitiveness Enhancement Program project VIU-RSCBMT-65/2019.

People suffering from allergies can be treated with repeated injections of increasing amounts of a specific allergen. This type of specific immunotherapy is currently the only way to treat the underlying pathological immune response associated with an allergy. The approach can afford long-lasting protection, but the process takes 3-5 years, can produce allergic reactions, and in severe cases treatment is often aborted due to anaphylaxis. However, treatment can be optimized with the use of specific adjuvants that modify the immune response, its duration, and that increase the production of the correct type of antibodies. In the pursuit of such adjuvants, two new trivalent acetylated β-(1→2)-linked mannobioses based on a previously discovered lead molecule were prepared. The new molecules, along with the previously developed lead, were investigated by rigorous NMR and molecular modeling experiments in order to elucidate their behavior and preferred conformations in solution. Furthermore, the molecules were subjected to a biological investigation in which their immunostimulatory properties were evaluated by assessing their effect on the production of TH 2-type cytokine interleukin-4 (IL-4) and Treg pro-inflammatory cytokine tumor necrosis factor (TNF). Treatment of peripheral mononuclear blood cell cultures from patients suffering from birch allergy with birch allergen Bet v induced a strong IL-4 response, whereas the same treatment together with the trivalent acetylated mannobioses caused significant suppression of the induced IL-4.

The quest for novel natural-like biomolecular probes that can be used to gain information on biological recognition events is of topical interest to several scientific areas. In particular, the recognition of carbohydrates by proteins modulates a number of important biological processes. These molecular recognition events are, however, difficult to study by the use of naturally occurring oligosaccharides and polysaccharides owing to their intrinsic structural heterogeneity and to the many technical difficulties encountered during the isolation of sufficient quantities of pure material for detailed structural and biological studies. Therefore, the construction of homogenous biomolecular probes that can mimic both the biophysical properties of polysaccharide backbones and the properties of bioactive oligosaccharide fragments are highly sought after. Herein, synthetic methodology for the construction of well-defined bioconjugates consisting of biologically relevant disaccharide fragments grafted onto a dextran backbone is presented, and a preliminary NMR spectroscopy study of their interactions with galectin-3 as a model lectin is conducted. The authors thank the Magnus Ehrnrooth foundation, the Ruth and Nils‐Erik Stenbäck foundation, Åbo Akademi University, and Turku Centre for Lifespan Research for financial support. Jarl Hemming at the Laboratory of Wood and Paper Chemistry at Åbo Akademi is thanked for technical assistance with the SEC/MALLS analysis. Leena Kaven‐Honka is thanked for preparing the C. albicans mannans. The group at CIC bioGUNE thanks Agencia Estatal de Investigacion and MINECO of Spain (CTQ2015‐64597‐C2‐1P and SEV‐2016‐0644 Severo Ochoa Excellence Acreditation) and the European Commission for the TOLLerant and GlycoVAX ITN projects. The authors acknowledge Prof. Francisco Javier Cañada‐Vicinay and Pablo Valverde for the acquisition of some NMR spectra and Dr. Filipa Marcelo for the generous gift of the plasmid of the hGal3 CRD.

The quest for novel natural-like biomolecular probes which can be utilized to gain information on biological recognition events is of topical interest to several scientific areas. In particular, the recognition of carbohydrates by proteins modulates a number of important biological processes. These molecular recognition events are, however, difficult to study by the use of naturally occurring oligosaccharides and polysaccharides due to their intrinsic structural heterogeneity as well as the many technical difficulties encountered during the isolation of sufficient quantities of pure material for detailed structural and biological studies. Therefore, the construction of homogenous biomolecular probes which would both mimic the biophysical properties of polysaccharide backbones and the properties of bioactive oligosaccharide fragments are highly sought after. Herein, we present a synthetic methodology for the construction of well-defined bioconjugates consisting of biologically relevant disaccharide fragments grafted onto a dextran backbone and conduct a preliminary NMR-spectroscopic study of their interactions with the model lectin galectin-3.

Craterellus tubaeformis (Funnel Chanterelle) is among the most abundant wild mushrooms in Finland. Three polysaccharide fractions were sequentially extracted from the fruiting bodies of C. tubaeformis, using hot water, 2% and 25% KOH solutions, respectively, and purified. The monomer composition, molecular weight, and chemical structure were determined using chromatographic and spectroscopic methods. Thermogravimetric analysis was performed as well. The hot water extract consisted mainly of high-molecular weight → 2,6)-α-Man-(1 → and → 6)-α-Gal-(1 → chains, covalently bound to proteins. The alkali extracts consisted of acidic → 6)-β-Glc-(1→, with branches of short → 3)-β-Glc-(1 → chains or single β-Glc residues. The use of alkali influenced the glycosidic linkages, molecular mass and thermal stability of the polysaccharide fractions. The use of KOH 2% increased the amount of low molecular weight polysaccharides, resulting in bimodal molecular weight distributions, with little impact on the thermal stability. Conversely, extraction with KOH 25% provided low molecular weight polysaccharides with substantially reduced thermal stability.

Polysubstituted cyclopentadienyl and indenyl complexes of ruthenium were synthesized and investigated to elucidate their potential cytotoxic activities. In particular, substituted (indenyl)ruthenium complexes inhibited the proliferation of a panel of human adherent cancer cells with comparable activity to reference agent cisplatin. One of the active compounds exerted a concentration dependent inhibition of cell cycle at G1–S transiton as evidenced by flow cytometry.

Polyhydroxylated steroids, such as brassinosteroids, phytoecdysteroids and steroid saponins, are structurally attractive compounds possessing a number of interesting biological properties. Accordingly, development of synthetic procedures to build steroid based structures mimicking the naturally occurring hydrophilic steroids is of topical interest. In the present work, a d -secoestrone derivative was modified further by Barbier-allylation – ring-closing metathesis – dihydroxylation sequence with the aim to prepare steroid based structures with limited hydrophilicity. A straightforward synthesis route was developed with the isolated yield for each step ranging from good to excellent. All compounds prepared were fully characterized by NMR spectroscopic techniques and completely assigned 1 H and 13 C spectra are reported herein. Finally, the effects of the synthesized amphiphilic steroid derivatives on the proliferation of cancer cells are reported and discussed.

Carbohydrates, being the most abundant class of biopolymers on earth, have, due to their structural diversity and inherent chirality, been subject to comprehensive biological investigations. Their biological importance is unquestionable, as a wide range of biological recognition and communication phenomena depend on complex oligo- and polysaccharide structures. This also makes carbohydrates attractive targets for developing new pharmaceuticals. In this chapter, a fundamental overview of the synthesis of oligosaccharides from the viewpoint of both traditional synthetic methods as well as fully automated methodologies is provided. Furthermore, selected commercially available oligosaccharide pharmaceuticals as well as promising new compounds under development are briefly discussed.

9 p.-2 tab.-6 fig., Phosphorylated β-(1→2)-oligomannosides are found on the cell surface of several Candida species, including Candida albicans (an opportunistic pathogen). These molecules are believed to take part in the invasion process of fungal infections, which in the case of C. albicans can lead to severe bloodstream infections and death, and can therefore be considered important from a biological standpoint. Understanding the mechanism of their action requires access to the corresponding oligosaccharide model compounds in pure form. In the present work, synthesis of the model core structures involved in the invasion process of C. albicans, consisting of phosphorylated β-(1→2)-linked mannotriose and tetraose, is reported. In order to elucidate the nature of these molecules in more detail, an extensive NMR-spectroscopic study encompassing complete spectral characterization, conformational analysis and molecular modelling was performed. The obtained results were also compared to similar chemical entities devoid of the charged phosphate group., The authors thank the Academy of Finland (Research Grant #252371) and Stiftelsens för Åbo Akademi Forskningsinstitut for financial support. The CMST COST Action CM1102 Multivalent Glycosystems for Nanoscience—MultiGlycoNano is thanked for STSM funding to J.R., who also further acknowledges Suomalaisten Kemistien Seura for Young Scientist Award granted for his M.Sc. thesis work based on this study.

International audience; Glycosylation is promoted by acid promoters rendering the reactions with basic acceptors challenging. This report presents an in depth study involving methyl 6-(hydroxymethyl)picolinate as the model acceptor and 22 glycosyl donors to afford the desired glycosides in good yields ranging from 46% to 85%. Several parameters were evaluated, including the protecting groups of the glycosyl donor, the leaving group at the anomeric center, and the promoter. The influence of the pyridine ring was evident with a benzene-based acceptor affording high yields of glycoside (79%) in comparison to the pyridine-based acceptor (46%). The present work provides a general and reliable access to pyridine-containing glycosides.