Diverging cell wall strategies for drought adaptation in two maize inbreds with contrasting lodging resistance.

The plant cell wall is a plastic structure of variable composition that constitutes the first line of defence against environmental challenges. Lodging and drought are two stressful conditions that severely impact maize yield. In a previous work, we characterised the cell walls of two maize inbreds, EA2024 (susceptible) and B73 (resistant) to stalk lodging. Here, we show that drought induces distinct phenotypical, physiological, cell wall, and transcriptional changes in the two inbreds, with B73 exhibiting lower tolerance to this stress than EA2024. In control conditions, EA2024 stalks had higher levels of cellulose, uronic acids and p-coumarate than B73. However, upon drought EA2024 displayed increased levels of arabinose-enriched polymers, such as pectin-arabinans and arabinogalactan proteins, and a decreased lignin content. By contrast, B73 displayed a deeper rearrangement of cell walls upon drought, including modifications in lignin composition (increased S subunits and S/G ratio; decreased H subunits) and an increase of uronic acids. Drought induced more substantial changes in gene expression in B73 compared to EA2024, particularly in cell wall-related genes, that were modulated in an inbred-specific manner. Transcription factor enrichment assays unveiled inbred-specific regulatory networks coordinating cell wall genes expression. Altogether, these findings reveal that B73 and EA2024 inbreds, with opposite stalk-lodging phenotypes, undertake different cell wall modification strategies in response to drought. We propose that the specific cell wall composition conferring lodging resistance to B73, compromises its cell wall plasticity, and renders this inbred more susceptible to drought.

Soluble Extracellular Polymeric Substances Produced by Parachlorella kessleri and Chlorella vulgaris: Biochemical Characterization and Assessment of Their Cadmium and Lead Sorption Abilities.

In the present study, the potential of lead and cadmium removal by the extracellular polymeric substances (EPS) produced from Parachlorella kessleri and Chlorella vulgaris were investigated. Carbohydrates were the dominant components of EPS from both analyzed species. The contents of reducing sugars, uronic acids, and amino acids were higher in EPS synthesized by C. vulgaris than in EPS from P. kessleri. The analysis of the monosaccharide composition showed the presence of rhamnose, mannose and galactose in the EPS obtained from both species. The ICP-OES (inductively coupled plasma optical emission spectrometry) analyses demonstrated that C. vulgaris EPS showed higher sorption capacity in comparison to P. kessleri EPS. The sorption capacity of C. vulgaris EPS increased with the increase in the amount of metal ions. P. kessleri EPS had a maximum sorption capacity in the presence of 100 mg/L of metal ions. The FTIR analysis demonstrated that the carboxyl, hydroxyl, and carbonyl groups of EPS play a key role in the interactions with metal ions. The present study showed C. vulgaris EPS can be used as a biosorbent in bioremediation processes due to its biochemical composition, the presence of significant amounts of negatively charged uronic acids, and higher sorption capacity.

Characterization of the exopolymer-producing Pseudoalteromonas sp. S8-8 from Antarctic sediment.

A synergistic approach using cultivation methods, chemical, and bioinformatic analyses was applied to explore the potential of Pseudoalteromonas sp. S8-8 in the production of extracellular polymeric substances (EPSs) and the possible physiological traits related to heavy metal and/or antibiotic resistance. The effects of different parameters (carbon source, carbon source concentration, temperature, pH and NaCl supplement) were tested to ensure the optimization of growth conditions for EPS production by the strain S8-8. The highest yield of EPS was obtained during growth in culture medium supplemented with glucose (final concentration 2%) and NaCl (final concentration 3%), at 15 °C and pH 7. The EPS was mainly composed of carbohydrates (35%), followed by proteins and uronic acids (2.5 and 2.77%, respectively) and showed a monosaccharidic composition of glucose: mannose: galactosamine: galactose in the relative molar proportions of 1:0.7:0.5:0.4, as showed by the HPAE-PAD analysis. The detection of specific molecular groups (sulfates and uronic acid content) supported the interesting properties of EPSs, i.e. the emulsifying and cryoprotective action, heavy metal chelation, with interesting implication in bioremediation and biomedical fields. The analysis of the genome allowed to identify a cluster of genes involved in cellulose biosynthesis, and two additional gene clusters putatively involved in EPS biosynthesis. KEY POINTS: • A cold-adapted Pseudoalteromonas strain was investigated for EPS production. • The EPS showed emulsifying, cryoprotective, and heavy metal chelation functions. • Three gene clusters putatively involved in EPS biosynthesis were evidenced by genomic insights.

An oxidative metabolic pathway of 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEHU) from alginate in an alginate-assimilating bacterium.

Alginate-assimilating bacteria degrade alginate into an unsaturated monosaccharide, which is converted into 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEHU). DEHU is reduced to 2-keto-3-deoxy-D-gluconate by a DEHU-specific reductase using NAD(P)H. This is followed by pyruvate production via the Entner-Doudoroff pathway. Previously, we identified FlRed as a DEHU reductase in an alginate-assimilating bacterium, Flavobacterium sp. strain UMI-01. Here, we showed that FlRed can also catalyze the oxidation of DEHU with NAD+, producing 2-keto-3-deoxy-D-glucarate (KDGR). FlRed showed a predilection for NADH and NAD+ over NADPH and NADP+, respectively, and the Km value for NADH was approximately 2.6-fold less than that for NAD+. Furthermore, we identified two key enzymes, FlDet and FlDeg, for KDGR catabolism. FlDet was identified as an enzyme of the ribonuclease activity regulator A family, which converts KDGR to α-ketoglutaric semialdehyde (α-KGSA). FlDeg, a type II α-KGSA dehydrogenase, generated α-ketoglutaric acid by oxidizing the aldehyde group of α-KGSA using NAD(P)+. Consequently, unlike the conventional DEHU reduction pathway, DEHU can be directly converted to α-ketoglutaric acid without consuming NAD(P)H. Alginate upregulated the expression of not only FlRed and two enzymes of the DEHU-reduction pathway, but also FlDet and FlDeg. These results revealed dual pathways of DEHU metabolism involving reduction or oxidation by FlRed.

D-Rhamnan and Pyruvate-Containing Teichuronic Acid from the Cell Wall of Rathayibacter sp. VKM Ac-2759.

Rathayibacter sp. VKM Ac-2759 (family Microbacteriaceae, class Actinobacteria) contains two glycopolymers in the cell wall. The main chain of rhamnan, glycopolymer 1, is built from the repeating tetrasaccharide units carrying terminal arabinofuranose residues at the non-reducing end, →3)-α-[α-D-Araf-(1→2)]-D-Rhap-(1→2)-α-D-Rhap-(1→3)-α-D-Rhap-(1→2)-α-D-Rhap-(1→. Similar to other described Rathayibacter species, rhamnose in the neutral glycopolymer of the VKM Ac-2759 strain is present in the D-configuration. Acetalated with pyruvic acid teichuronic acid, glycopolymer 2, is composed of the repeating tetrasaccharide units, →4)-ß-D-GlcpA-(1→4)-ß-D-Galp-(1→4)-ß-D-Glcp-(1→3)-ß-[4,6-S-Pyr]-D-Manp-(1→. Glycopolymers 1 and 2 were identified in prokaryotic microorganisms for the first time and their structures were established by chemical analysis and NMR spectroscopy. The obtained data can be used in taxonomic research, as well as for elucidating the mechanisms of plant colonization and infection by bacteria of the Rathayibacter genus.

Anti-glycation effect of Ecklonia cava polysaccharides extracted by combined ultrasound and enzyme-assisted extraction.

The anti-glycation effects of polysaccharides from Ecklonia cava were examined according to extraction method-hot buffer (HP), ultrasound (UP), enzyme (EP), or a combination of ultrasound and enzyme (UEP). The physicochemical properties, monosaccharide compositions, and structural characteristics of the polysaccharides were determined. UP, EP, and UEP had higher fucose and galactose compositions than HP. The FT-IR spectra of samples showed the presence of sulfate esters and 4-sulfate galactose. 1H NMR indicated that alginate was removed by purification. UP, EP, and UEP possessed higher sulfate contents than HP. UEP presented with the highest extraction yield and lowest protein and uronic acid contents. The levels of AGE formation, as well as fructosamine, α-dicarbonyl, and protein carbonyl contents were determined during a 3-week incubation in a BSA/fructose system. UEP and UP effectively inhibited AGE, although the inhibition effect was lower than that of aminoguanidine. However, UP and UEP showed higher inhibition of fructosamine, α-dicarbonyl, and protein carbonyl than aminoguanidine. AGE formation was negatively correlated with sulfate content and some monosaccharide compositions (fucose, galactose, and glucose), but positively correlated with molecular weight. Overall, the present study suggests that UEP is a suitable extraction method for obtaining anti-glycation agents from E. cava.

Uronic acid metabolic process-related gene expression-based signature predicts overall survival of glioma.

Glioma is the most common and malignant cancer of the central nervous system, and the prognosis is poor. Metabolic reprogramming is a common phenomenon that plays an important role in tumor progression including gliomas. Searching the representative process among numerous metabolic processes to evaluate the prognosis aside from the glycolytic pathway may be of great significance. A novel prediction signature was constructed in the present study based on gene expression. A total of 1027 glioma samples with clinical and RNA-seq data were used in the present study. Lasso-Cox, gene set variation analysis, Kaplan-Meier survival curve analysis, Cox regression, receiver operating characteristic curve, and elastic net were performed for constructing and verifying predictive models. The R programming language was used as the main tool for statistical analysis and graphical work. This signature was found to be stable in prognostic prediction in the Chinese Glioma Genome Atlas Network and the Cancer Genome Atlas databases. The possible mechanism was also explored, revealing that the aforementioned signature was closely related to DNA replication and ATP binding. In summary, a prognosis prediction signature for patients with glioma based on five genes was constructed and showed great potential for clinical application.

The Cell Wall of Bacillus subtilis.

The cell wall of Bacillus subtilis is a rigid structure on the outside of the cell that forms the first barrier between the bacterium and the environment, and at the same time maintains cell shape and withstands the pressure generated by the cell's turgor. In this review, the chemical composition of peptidoglycan, teichoic and teichuronic acids, the polymers that comprise the cell wall, and the biosynthetic pathways involved in their synthesis will be discussed, as well as the architecture of the cell wall. B. subtilis has been the first bacterium for which the role of an actin-like cytoskeleton in cell shape determination and peptidoglycan synthesis was identified and for which the entire set of peptidoglycan synthesizing enzymes has been localised. The role of the cytoskeleton in shape generation and maintenance will be discussed and results from other model organisms will be compared to what is known for B. subtilis. Finally, outstanding questions in the field of cell wall synthesis will be discussed.

Mutations in the Pectin Methyltransferase QUASIMODO2 Influence Cellulose Biosynthesis and Wall Integrity in Arabidopsis.

Pectins are abundant in the cell walls of dicotyledonous plants, but how they interact with other wall polymers and influence wall integrity and cell growth has remained mysterious. Here, we verified that QUASIMODO2 (QUA2) is a pectin methyltransferase and determined that QUA2 is required for normal pectin biosynthesis. To gain further insight into how pectin affects wall assembly and integrity maintenance, we investigated cellulose biosynthesis, cellulose organization, cortical microtubules, and wall integrity signaling in two mutant alleles of Arabidopsis (Arabidopsis thaliana) QUA2, qua2 and tsd2 In both mutants, crystalline cellulose content is reduced, cellulose synthase particles move more slowly, and cellulose organization is aberrant. NMR analysis shows higher mobility of cellulose and matrix polysaccharides in the mutants. Microtubules in mutant hypocotyls have aberrant organization and depolymerize more readily upon treatment with oryzalin or external force. The expression of genes related to wall integrity, wall biosynthesis, and microtubule stability is dysregulated in both mutants. These data provide insights into how homogalacturonan is methylesterified upon its synthesis, the mechanisms by which pectin functionally interacts with cellulose, and how these interactions are translated into intracellular regulation to maintain the structural integrity of the cell wall during plant growth and development.

Rhamnomannans and Teichuronic Acid from the Cell Wall of Rathayibacter tritici VKM Ac-1603T.

The structures of three cell wall glycopolymers of the phytopathogen Rathayibacter tritici VKM Ac-1603T (family Microbacteriaceae, order Micrococcales, class Actinobacteria) were established by chemical methods and NMR spectroscopy. Polymer 1 is a branched rhamnomannan with the repeating unit →3)-α-[ß-D-Xylp-(1→2)]-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 2 is a linear rhamnomannan with the repeating unit →2)-α-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 3 is a branched teichuronic acid containing monosaccharide residues GlcA, Gal, Man, and Glc at a 1 : 1 : 1 : 5 ratio (see the text for the structures). It has been demonstrated that representatives of four Rathayibacter species studied to date (R. tritici VKM Ac-1603T, R. iranicus VKM Ac-1602 T, R. toxicus VKM Ac-1600 and "Rathayibacter tanaceti" VKM Ac-2596) contain differing patterns of phosphate-free glycopolymers. At the same time, the above Rathayibacter strains have a common property - the presence of rhamnomannans with D-rhamnose. These rhamnomannans may be linear or branched and differing in the positions of glycosidic bonds and side substituents. The presence in the cell wall of rhamnomannans with D-rhamnose may serve as useful chemotaxonomic marker of the genus Rathayibacter.

Locating Methyl-Etherified and Methyl-Esterified Uronic Acids in the Plant Cell Wall Pectic Polysaccharide Rhamnogalacturonan II.

Rhamnogalacturonan II (RG-II) is a structurally complex pectic polysaccharide that exists as a borate ester cross-linked dimer in the cell walls of all vascular plants. The glycosyl sequence of RG-II is largely conserved, but there is evidence that galacturonic acid (GalA) methyl etherification and glucuronic acid (GlcA) methyl esterification vary in the A sidechain across plant species. Methyl esterification of the galacturonan backbone has also been reported but not confirmed. Here we describe a new procedure, utilizing aq. sodium borodeuteride (NaBD4)-reduced RG-II, to identify the methyl esterification status of backbone GalAs. Our data suggest that up to two different GalAs are esterified in the RG-II backbone. We also adapted a procedure based on methanolysis and NaBD4 reduction to identify 3-, 4-, and 3,4-O-methyl GalA in RG-II. These data, together with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF) MS analysis of sidechain A generated from selected RG-IIs and their NaBD4-reduced counterparts, suggest that methyl etherification of the ß-linked GalA and methyl esterification of the GlcA are widespread. Nevertheless, the extent of these modifications varies between plant species. Our analysis of the sidechain B glycoforms in RG-II from different dicots and nonpoalean monocots suggests that this sidechain has a minimum structure of an O-acetylated hexasaccharide (Ara-[MeFuc]-Gal-AceA-Rha-Api-). To complement these studies, we provide further evidence showing that dimer formation and stability in vitro is cation and borate dependent. Taken together, our data further refine the primary sequence and sequence variation of RG-II and provide additional insight into dimer stability and factors controlling dimer self-assembly.

Chemoenzymatic synthesis of the pH responsive surfactant octyl ß-D-glucopyranoside uronic acid.

Methodology was developed to expand the range of benign alkyl glycoside surfactants to include also anionic types. This was demonstrated possible through conversion of the glycoside to its carboxyl derivative. Specifically, octyl ß-D-glucopyranoside (OG) was oxidised to the corresponding uronic acid (octyl ß-D-glucopyranoside uronic acid, OG-COOH) using the catalyst system T. versicolor laccase/2,2,6,6-tetramethylpiperidinyloxy (TEMPO) and oxygen from air as oxidant. The effects of oxygen supply methodology, concentrations of laccase, TEMPO and OG as well as reaction temperature were evaluated. At 10 mM substrate concentration, the substrate was almost quantitatively converted into product, and even at a substrate concentration of 60 mM, 85% conversion was reached within 24 h. The surfactant properties of OG-COOH were markedly dependent on pH. Foaming was only observed at low pH, while no foam was formed at pH values above 5.0. Thus, OG-COOH can be an attractive low-foaming surfactant, for example for cleaning applications and emulsification, in a wide pH range (pH 1.5-10.0).

Identification and Characterization of Citrus Peel Uronic Acid Oxidase.

Uronic acid-rich plant materials such as pectin are potential renewable feedstocks for the chemical industry. Uronic acid oxidase activity was first reported in extracts of citrus leaves, and was subsequently found to be widely distributed in plants, with the highest activity detected in extracts of the pectin-rich citrus peel. Herein we report the identification of the primary sequence of uronic acid oxidase from extracts of the peel of Citrus sinensis, by partial purification and protein mass spectrometry. Activity of the enzyme, a member of the berberine bridge family, was confirmed by recombinant expression in Pichia pastoris. Biochemical characterization of the recombinant enzyme is reported. Our findings facilitate further investigation of the biological function of uronic acid oxidation in the economically important orange fruit, and also provide a basis for the development of a catalyst for bioconversion of uronic acids.

Penicillium camemberti galacturonate reductase: C-1 oxidation/reduction of uronic acids and substrate inhibition mitigation by aldonic acids.

The enzyme galacturonate oxidoreductase PcGOR from Penicillium camemberti reduces the C-1 carbon of D-glucuronate and C-4 epimer D-galacturonate to their corresponding aldonic acids, important reactions in both pectin catabolism and ascorbate biosynthesis. PcGOR was active on both glucuronic acid and galacturonic acid, with similar substrate specificities (kcat/Km) using the preferred co-substrate NADPH. Substrate acceptance extended to lactone congeners, and D-glucurono-3,6-lactone was converted to L-gulono-1,4-lactone, an immediate precursor of ascorbate. Reaction with glucuronate showed only minor substrate inhibition, and the product L-gulonate and L-gulono-1,4-lactone were both found to be competitive inhibitors with Ki in the low mM range. In contrast, reaction with C-4 epimer galacturonate displayed marked substrate inhibition. Moreover, the product L-galactonate and L-galactono-1,4-lactone were observed to mitigate substrate inhibition by galacturonate, with the lactone having a greater effect than the acid.

Uncovering the reactive nature of 4-deoxy-L-erythro-5-hexoseulose uronate for the utilization of alginate, a promising marine biopolymer.

Alginate is a linear polyuronate in brown macroalgae. It is also a promising marine biopolymer that can be degraded by exo-type alginate lyase into an unsaturated uronate that is non-enzymatically or enzymatically converted to 4-deoxy-L-erythro-5-hexoseulose uronate (DEH). In a bioengineered yeast Saccharomyces cerevisiae (DEH++) strain that utilizes DEH, DEH is not only an important physiological metabolite but also a promising carbon source for biorefinery systems. In this study, we uncovered the essential chemical nature of DEH. In particular, we showed that DEH non-enzymatically reacts with specific amino groups in Tris, ammonium salts [(NH4)2SO4 and NH4Cl], and certain amino acids (e.g., Gly, Ser, Gln, Thr, and Lys) at 30 °C and forms other compounds, one of which we tentatively named DEH-related product-1 (DRP-1). In contrast, Asn, Met, Glu, and Arg were almost inert and Ala, Pro, Leu, Ile, Phe, Val, and Asp, as well as sodium nitrate (NaNO3), were inert in the presence of DEH. Some of the above amino acids (Asn, Glu, Ala, Pro, Phe, and Asp) were suitable nitrogen sources for the DEH++ yeast strain, whereas ammonium salts and Ser, Gln, and Thr were poor nitrogen sources owing to their high reactivity to DEH. Nutrient-rich YP medium with 1% (w/v) Yeast extract and 2% (w/v) Tryptone, as well as 10-fold diluted YP medium, could also be effectively used as nitrogen sources. Finally, we identified DRP-1 as a 2-furancarboxylic acid and showed that it has a growth-inhibitory effect on the DEH++ yeast strain. These results show the reactive nature of DEH and suggest a basis for selecting nitrogen sources for use with DEH and alginate in biorefineries. Our results also provide insight into the physiological utilization of DEH. The environmental source of 2-furancarboxylic acid is also discussed.

Effect of Liposomal Delivery of Oxidized Dextran with Isonicotinic Acid Hydrazide on Component Profile of Pulmonary Extracellular Matrix in Mice with BCG-Induced Granulomatosis.

Intraperitoneal injections of isonicotinic acid hydrazide (INH), dextrazide (oxidized dextran+INH), or liposomes loaded with dextrazide (INH dose of 14 mg/kg) over 2 months to mice with BCG-induced granulomatosis started from postinfection day 90 induced qualitative and quantitative changes in composition of pulmonary extracellular matrix. Both dextrazide and its liposomal form decreased the levels of sulfated glycosaminoglycans and uronic acids. In contrast to INH, both preparations did not decrease the levels of total glycosaminoglycans, proteins, and galactose. This difference is explained by the fact both free and liposomal dextrazide activated MMP, but did not increase the content of TIMP-1 and TIMP-2, whereas injection of INH was followed by an increase in TIMP-2 content and a decrease in the level of free hydroxyproline, which attested to down-regulation of collagen degradation and maintenance of the conditions for pulmonary fibrosis in mice of this group.

The activation of RAW264.7 murine macrophage and natural killer cells by glucomannogalactan polysaccharides from Tornabea scutellifera.

A water-soluble polysaccharide was isolated from Tornabea scutellifera and fractionated using a DAEA Sepharose FF column to evaluate its capacity to stimulate natural killer (NK) cells and macrophages. Neutral sugars (71.8-93.5%) constituted the major part of crude polysaccharides and fractions (TSF1 and TSF2) with relatively lower levels of proteins (0.4-20.3%) and uronic acids (0.8-4.9%). The weight average molecular weights (Mw) of 152.7-537.3 × 103 g/mol were measured for isolated polysaccharides. The polysaccharides were composed of glucose (14.4-44.0%), galactose (23.2-43.2%), mannose (28.5-34.2%) and rhamnose (2.6-13.9%) units connected through (1→2)-Galp, (1→2,6)-Galp, (1→4)-Glcp, (1→6)-Glcp, (1→3)-Rhap, (1→2)-Rhap and (1→4)-Manp residues. TSF2 polysaccharide effectively induced RAW264.7 murine macrophages to release nitric oxide, TNF-α, IL-1ß and IL-6, and activated NK cells to produce TNF-α, INF-γ, granzyme-B, perforin, NKG2D and FasL through NF-κB and MAPKs signaling pathways. Overall results suggested that polysaccharides from T. scutellifera could be potent immunostimulatory compounds inducing both macrophages and NK cells.

Bioactive Exopolysaccharides Reveal Camellia oleifera Infected by the Fungus Exobasidium gracile Could Have a Functional Use.

Camellia oleifera is an important Chinese commercial crop. Camellia oleifera can display abnormal leaves due to infection by the parasitic fungus Exobasidium gracile. Exobasidium gracile was isolated from infected leaves and used in fermentation, and exopolysaccharides EP0-1 and EP0.5-1 were purified from the fermentation broth. EP0-1 was an alkaline polysaccharide consisting mainly of the linkages α-d-Manp(1→, →2)-α-d-Manp(1→ and →6)-α-d-Manp(1→, →3)-α-d-Glcp(1→ and→4)-α-d-Glcp(1→, terminal ß-d-Galf, (1→5)-ß-d-Galf, and terminal ß-D-GlcN(1→. EP0.5-1 was an acidic galactofuranose-containing polysaccharide. It contained the linkages of α-d-Manp(1→, →2)-α-d-Manp(1→, →6)-α-d-Manp(1→,→2, 6)-α-d-Manp(1→, →4)-α-d-Glcp(1→, and →4)-α-d-GlcUA(1→. Galactofuranose linkages were composed of terminal ß-d-Galf, (1→6)-ß-d-Galf and (1→2)-ß-d-Galf. Exobasidium gracile exopolysaccharides displayed significant immunoregulatory activity by activating macrophages. This research indicates that infected leaves from Camellia oleifera including the exopolysaccharides produced by the parasitic fungus Exobasidium gracile by are worth further investigation as a functional product.

Deep-sea Hydrothermal Vent Bacteria as a Source of Glycosaminoglycan-Mimetic Exopolysaccharides.

Bacteria have developed a unique strategy to survive in extreme environmental conditions through the synthesis of an extracellular polymeric matrix conferring upon the cells a protective microenvironment. The main structural component of this complex network constitutes high-molecular weight hydrophilic macromolecules, namely exopolysaccharides (EPS). EPS composition with the presence of particular chemical features may closely be related to the specific conditions in which bacteria evolve. Deep-sea hydrothermal vent bacteria have already been shown to produce EPS rich in hexosamines and uronic acids, frequently bearing some sulfate groups. Such a particular composition ensures interesting functional properties, including biological activities mimicking those known for glycosaminoglycans (GAG). The aim of the present study was to go further into the exploration of the deep-sea hydrothermal vent IFREMER (French Research Institute for Exploitation of the Sea) collection of bacteria to discover new strains able to excrete EPS endowed with GAG-like structural features. After the screening of our whole collection containing 692 strains, 38 bacteria have been selected for EPS production at the laboratory scale. EPS-producing strains were identified according to 16S rDNA phylogeny. Chemical characterization of the obtained EPS highlighted their high chemical diversity with the presence of atypical compositional patterns. These EPS constitute potential bioactives for a number of biomedical applications, including regenerative medicines and cancer treatment.

Use of HCV Ab+/NAT- donors in HCV naïve renal transplant recipients to expand the kidney donor pool.

Hepatitis C (HCV) disease transmission from the use of HCV antibody-positive and HCV nucleic acid test-negative (HCV Ab+/NAT-) kidneys have been anecdotally reported to be absent. We prospectively analyzed kidney transplant (KT) outcomes from HCV Ab+/NAT- donors to HCV naïve recipients under T-cell depleting early steroid withdrawal immunosuppression. Allografts from 40 HCV Ab+/NAT- donors were transplanted to 52 HCV Ab- recipients between July 2016 and February 2018. Thirty-three (82.5%) of donors met Public Health Service (PHS) increased risk criteria. De novo HCV infection was detected at 3 months post-KT in one recipient (1.9%). This was a case of transmission from a HCV Ab+ NAT+ donor with an initial false-negative NAT completed using sample collected on donor hospital admission (day 2). At the time of HCV diagnosis, a stored donor sample collected during procurement (day 4) was tested and resulted NAT-positive. Subsequently, sustained virologic response (SVR) was achieved with 12 weeks of glecaprevir/pibrentasvir. One death with functioning graft at 261 days post-KT was determined not related to HCV or donor factors. This experience provides evidence of a low transmission rate of HCV from HCV Ab+/ NAT- kidney donors, thereby arguing for increasing utilization.