D-gluconic Acid Research Articles

Naturalized dyes — A way to increase susceptibility for microbiological degradation

Aim of the study was the determination of the influence of the D-gluconic acid and its acetyl derivative (2,3,4,5,6-penta-O-acetyl-D-gluconic acid) on microbiological degradation in aerobic conditions of azo dyes (Schaffer salt and I acid derivatives). The rest of the aldonic acid and its acetylated form in the structure of azo dye play a role of an additional source of carbon for the used microorganisms. To investigations were used fungus: Aspergillus niger, Geotrichum condidum and bacterias: Pseudomonas fluorescens, Streptomyces roseochromogens. From all tested microorganisms only Aspergillus niger and Pseudomonas fluorescens show sufficient ability to decomposition of tested dyes during research carried out in shaken culture.

Acetobacter thailandicus sp. nov., for a strain isolated in Thailand

A Gram-negative, rod-shaped, and non-motile bacterium, designated as isolate AD25T, was isolated from a flower of the blue trumpet vine (Thunbergia laurifolia) at Tong Pha Phum, Kanchanaburi, Thailand. Phylogenetic analyses of 16S rRNA gene, 16S-23S rRNA gene internal transcribed spacer (ITS) region, and groEL gene sequences showed that the isolate was quite remote and constituted a cluster independent from the type strains of other Acetobacter species. The isolate was closely related to Acetobacter cibinongensis, one of the closest relatives, with 98.3 % 16S rRNA gene sequence similarity. The DNA G -+- C content of the isolate was 51.4 mol%. The isolate grew intensely on 10 % ethanol with 1.5 % D-glucose in the presence of 0.3 % peptone and 0.3 % yeast extract, and grew weakly on 3.0 % D-glucose in the presence of 0.1 % ammonium sulfate as the sole source of nitrogen. The isolate produced only D-gluconic acid from D-glucose. Based on physiological, biochemical, and genotypic differences between the isolate and the type strains of the validly named species, it is proposed that the isolate be classified as a novel species of Acetobacter, for which the name Acetobacter thailandicus sp. nov. is introduced. The type strain is isolate AD25T (= BCC 15839T = NBRC 103583T).

Synthesis and Characterization ofN-alkyl-N′-glucosylhexanediamine Surfactant

AbstractThe synthesis and structural analysis of glucosamide surfactants of the general formula CnH2n+1NH(CH2)6NHCO(CHOH)4CH2OH (n = 8, 10, 12) were described, and the surface activity properties of the surfactants were studied, and the interfacial tensions betweenn-octane and the aqueous surfactant solution were measured.N-alkylhexanediamines were synthesized by the alkylation of the 1,6-hexanediamine with alkyl bromide. The glucosamide surfactants,N-alkyl-N′-glucosylhexanediamine (CnGA), were prepared by amidation of the precursor diamine with D-gluconic acid δ-lactone. They were structurally characterized by IR,1H NMR and MS. They reduced the surface tension of water to approximately 28–33 mN · m−1at concentration levels of (0.2–1.0) × 10−3mol · L−1, and reduced the interfacial tensions betweenn-octane and the aqueous surfactant solution to approximately 1–2 mN · m−1at concentration levels of (0.3–4.2) × 10−3mol · L−1.

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane.

Graft polyrotaxanes, with poly(ε-caprolactone) (PCL) graft chains on the ring components were synthesized by the simultaneous ring-opening polymerization of ε-caprolactone from both ends of the backbone polymer, an end-functionalized polyethylene glycol (PEG) and the formation of inclusion complexes with α-cyclodextrin (α-CD). PEG with multiple functional groups at each end was prepared by the condensation of PEG-amine and D-gluconic acid; the PEG derivative formed an inclusion complex with α-CD. The polymerization of multiple hydroxy groups at the backbone ends resulted in a star-shaped end group, which served as a bulky capping group to prevent dethreading. In contrast, PEG with only one hydroxy group at each end did not produce polyrotaxanes, indicating that single PCL chains were too thin to confine α-CDs to the complex. In addition, the grafting polymerization proceeded properly only when robust hydrogen bonds formed between α-CDs were dissociated using a basic catalyst. Since the dissociation also induced dethreading, kinetic control of the polymerization and dissociation were crucial for producing graft polyrotaxanes. Consequently, this three-step reaction yielded graft polyrotaxanes in a good yield, demonstrating a significant simplification of the synthesis of graft polyrotaxanes.

Vibrio madracius sp. nov. isolated from Madracis decactis (Scleractinia) in St Peter & St Paul Archipelago, Mid-Atlantic Ridge, Brazil.

Three novel isolates (A-354(T), A-328, and A-384) were retrieved from apparently healthy scleractinian Madracis decactis in the remote St Peter & St Paul Archipelago, Mid-Atlantic Ridge, Brazil. The novel isolates formed a distinct lineage based on the phylogenetic reconstruction using the 16S rRNA and pyrH gene sequences. They fell into the Mediterranei clade and their closest phylogenetic neighbour was V.mediterranei species, sharing upto 98.1% 16S rRNA gene sequence similarity. Genomic analysis including in silico DDH, MLSA, AAI and genomic signature distinguished A-354(T) from V.mediterranei LMG 19703 (=AK1) with values of 33.3, 94.2, 92%, and 11.3, respectively. Phenotypically, the novel isolates can be differentiated from V.mediterranei based on the four following features. They do not grow at 8% NaCl; use D-gluconic acid but not L-galactonic acid lactone as carbon source; and do not have the fatty acid C18:0. Differentiation from both the other Mediterranei clade species (V.maritimus and V.variabilis) is supported by fifteen features. The novel species show lysine decarboxylase and tryptophan deaminase, but not gelatinase and arginine dihydrolase activity; produce acetoin; use α-D-lactose, N-acetyl-D-galactosamine, myo-Inositol, D-gluconic acid, and β-hydroxy-D,L-butyric acid; and present the fatty acids C14:0 iso, C15:0 anteiso, C16:0 iso, C17:0 anteiso, and C17:1x8c . Whole-cell protein profiles, based on MALDI-TOF, showed that the isolates are not clonal and also distinguished them from the closes phylogenetic neighbors. The name Vibrio madracius sp. nov. is proposed to encompass these novel isolates. The G+C content of the type strain A-354(T) (=LMG 28124(T)=CBAS 482(T)) is 44.5mol%.

Crystal structure and thermochemical properties of a novel coordination compound manganese d-gluconate tetrahydrate

A novel coordination compound of d-gluconic acid with the divalent manganese ion, Mn[(D-C6H11O7)2(H2O)2]·2H2O, is synthesized. The compound has an obvious bioactivity and can be used as a manganese dietary supplements and energy fortifier in medicine and food. Chemical analysis, elemental analysis, and X-ray crystallography are used to characterize its composition, crystal structure and chelating mode of d-gluconic acid with the divalent manganese ion. Single-crystal X-ray analysis reveals that the compound is formed by two d-gluconate anions, one manganese (II) cation, two coordinated waters and two crystal waters. And the two d-gluconate anions in Mn[(D-C6H11O7)2(H2O)2]·2H2O have two different conformations. The compound exhibits the chelate property of d-gluconate anions to manganese (II) cations, and the manganese (II) cation is six-coordinated and chelated by two d-gluconate anions and two coordinated waters. The lattice potential energy and ionic volume of the anion are obtained from crystallographic data. In accordance with Hess’ law, a reasonable thermochemical cycle is designed and the standard molar enthalpy of formation of the compound is calculated as an important physical quantity in relation with the energy state of the compound by use of an isoperibol solution-reaction calorimeter. Molar enthalpies of dissolution of the compound at various molalities are measured at T=298.15K in the double-distilled water. According to Pitzer’s theory, molar enthalpy of dissolution of the title compound at infinite dilution is calculated to be ΔsHm∞=(14.56±0.56)kJ·mol-1. The values of relative apparent molar enthalpies (ΦL) and relative partial molar enthalpies of the solvent (L1‾) and the compound (L2‾) at different concentrations m/(mol·kg−1) are derived from the experimental values of the enthalpies of dissolution of the compound.

Chemical remediation of wood treated with micronised, nano or soluble copper preservatives

Abstract The potential for extraction of copper from wood treated with micronised, nano or soluble forms of copper has been evaluated in view of chemical remediation. In focus were EDTA, oxalic acid, bioxalate, and d-gluconic acid for extraction of Cu from treated wood. Bioxalate extractions for 24 h resulted in Cu removal over 95% for all tested materials, and the effectiveness of oxalic acid extraction was very similar to that of nano-CuO-treated wood. Bioxalate was more effective than oxalic acid in removing Cu from ACQ-D, MCQ, MCA, CA-C and Cu-ethanolamine treated wood. d-gluconic acid extractions resulted in the lowest Cu removal for nano-CuO even though d-gluconic acid was effective for all other materials. As the pH of d-gluconic acid decreased, Cu removal was improved except for nano-CuO. There is no distinctive difference in Cu removal from wood treated with ACQ-D, MCQ, CA-C, MCA and Cu-ethanolamine.

Accumulation of the Mycotoxin Patulin in the Presence of Gluconic Acid Contributes to Pathogenicity of Penicillium expansum

Penicillium expansum, the causal agent of blue mold rot, causes severe postharvest fruit maceration through secretion of D-gluconic acid (GLA) and secondary metabolites such as the mycotoxin patulin in colonized tissue. GLA involvement in pathogenicity has been suggested but the mechanism of patulin accumulation and its contribution to P. expansum pathogenicity remain unclear. The roles of GLA and patulin accumulation in P. expansum pathogenicity were studied using i) glucose oxidase GOX2-RNAi mutants exhibiting decreased GOX2 expression, GLA accumulation, and reduced pathogenicity; ii) IDH-RNAi mutants exhibiting downregulation of IDH (the last gene in patulin biosynthesis), reduced patulin accumulation, and no effect on GLA level; and iii) PACC-RNAi mutants exhibiting downregulation of both GOX2 and IDH that reduced GLA and patulin production. Present results indicate that conditions enhancing the decrease in GLA accumulation by GOX2-RNAi and PACC-RNAi mutants, and not low pH, affected patulin accumulation, suggesting GLA production as the driving force for further patulin accumulation. Thus, it is suggested that GLA accumulation may modulate patulin synthesis as a direct precursor under dynamic pH conditions modulating the activation of the transcription factor PACC and the consequent pathogenicity factors, which contribute to host-tissue colonization by P. expansum.

Gluconobacter cerevisiae sp. nov., isolated from the brewery environment

Three strains, LMG 27748(T), LMG 27749 and LMG 27882 with identical MALDI-TOF mass spectra were isolated from samples taken from the brewery environment. Analysis of the 16S rRNA gene sequence of strain LMG 27748(T) revealed that the taxon it represents was closely related to type strains of the species Gluconobacter albidus (100 % sequence similarity), Gluconobacter kondonii (99.9 %), Gluconobacter sphaericus (99.9 %) and Gluconobacter kanchanaburiensis (99.5 %). DNA-DNA hybridization experiments on the type strains of these species revealed moderate DNA relatedness values (39-65 %). The three strains used d-fructose, d-sorbitol, meso-erythritol, glycerol, l-sorbose, ethanol (weakly), sucrose and raffinose as a sole carbon source for growth (weak growth on the latter two carbon sources was obtained for strains LMG 27748(T) and LMG 27882). The strains were unable to grow on glucose-yeast extract medium at 37 °C. They produced acid from meso-erythritol and sucrose, but not from raffinose. d-Gluconic acid, 2-keto-d-gluconic acid and 5-keto-d-gluconic acid were produced from d-glucose, but not 2,5-diketo-d-gluconic acid. These genotypic and phenotypic characteristics distinguish strains LMG 27748(T), LMG 27749 and LMG 27882 from species of the genus Gluconobacter with validly published names and, therefore, we propose classifying them formally as representatives of a novel species, Gluconobacter cerevisiae sp. nov., with LMG 27748(T) ( = DSM 27644(T)) as the type strain.

Development and validation of an indirect pulsed electrochemical detection method for monitoring the inhibition of Abl1 tyrosine kinase

A new method for monitoring the enzyme inhibition of Abl1 tyrosine kinase by liquid chromatography–indirect pulsed electrochemical detection (LC–InPED) was developed. In this method, adsorption of a peptide analyte at the noble metal electrode suppresses the oxidation of polyols under alkaline condition to elicit an indirect response resulting in a negative peak of the target peptide. Among the reagents tested, d-gluconic acid sodium salt gave the best overall signal to noise (S/N) values for the indirect detection of p-Abltide, the product of Abl1 enzymatic reaction. 50μM d-gluconic acid sodium salt dissolved in a mixture of 78% water–22% acetonitrile–0.03% trifluoroacetic acid (TFA) was used as the mobile phase. Chromatographic separation was achieved on an Alltima C18 (I.D. 5μm; 250mm×4.6mm) column with the mobile phase flow rate of 0.5ml/min. 0.5M sodium hydroxide was added post-column to maintain alkaline conditions in the PED cell. The limit of quantification (LOQ) was 0.2μM for p-Abltide, which was about 50-fold lower than direct PED analysis. The residual plot of the linear calibration curve indicated a good fit with a linear model within the investigated concentration range of p-Abltide. Intra- and inter-day precision was not more than 6.5% and accuracy was from −5.75% to +1.54%. The validated LC–InPED method was successfully applied for monitoring of p-Abltide in Abl1 enzyme reaction and the inhibition study of Abl1. The determined IC50 values of model inhibitors, imatinib, nilotinib and dasatinib, were 601.4nM (R2=0.99), 32.3nM (R2=0.99) and 1.3nM (R2=0.98), respectively. These results were consistent with literature data. To the best of our knowledge this is the first time a LC–InPED method has been used to monitor an enzyme reaction.

Discovery of cellobionic acid phosphorylase in cellulolytic bacteria and fungi

A novel phosphorylase was characterized as new member of glycoside hydrolase family 94 from the cellulolytic bacterium Xanthomonas campestris and the fungus Neurospora crassa. The enzyme catalyzed reversible phosphorolysis of cellobionic acid. We propose 4-O-β-d-glucopyranosyl-d-gluconic acid: phosphate α-d-glucosyltransferase as the systematic name and cellobionic acid phosphorylase as the short names for the novel enzyme. Several cellulolytic fungi of the phylum Ascomycota also possess homologous proteins. We, therefore, suggest that the enzyme plays a crucial role in cellulose degradation where cellobionic acid as oxidized cellulolytic product is converted into α-d-glucose 1-phosphate and d-gluconic acid to enter glycolysis and the pentose phosphate pathway, respectively.

Effects of traditional Chinese medicine on rats with Type II diabetes induced by high-fat diet and streptozotocin: A urine metabonomic study

Type II diabetes has become a serious threat to human health in recent years. Among adults above 20 years old in China, the prevalence rate of diabetes is 9.7%. Thus, it is imperative to study the mechanisms underlying type II diabetes to develop effective therapeutic treatments. To examine metabolic changes in a rat model of type II diabetes and explore mechanisms underlying the beneficial effects of traditional Chinese medicine (TCM) in this model. 120 rats were divided into four groups, including a control group, a high-fat diet group (high-fat diet and streptozotocin injection), a TCM group (high-fat diet, streptozotocin injection, followed by TCM administration), and a rosiglitazone maleate group (high-fat diet, streptozotocin injection, followed by rosiglitazone maleate administration). Metabolites in urine samples from 1-3 weeks (time point 1) and 4-6 weeks (time point 2) of drug administration were compared by gas chromatography-mass spectrometry (GC-MS). Our results showed that in the high-fat diet group, at time point 2, the levels of dihydroxybenzoic acid, L-ascorbic acid, D-gluconic acid, octadecanoic acid, and glutaric acid in urine were significantly higher than at time point 1. In the TCM group, at time point 2, the urine levels of L-ascorbic acid were markedly lower than at time point 1. Our studies demonstrated that examining urine metabolic changes provided important insights into the mechanisms underlying type II diabetes as well as the therapeutic effects of TCM.

Genetic diversity of phosphate-solubilizing peanut (Arachis hypogaea L.) associated bacteria and mechanisms involved in this ability

In this study, attempts were made to analyze mechanisms involved in the bacterial phosphate-solubilizing ability of peanut isolates. Bacteria were taxonomically identified by analysis of 16S rDNA sequence. Levels of soluble P released by the isolates in unbuffered or buffered with Tris–HCl or MES NBRIP-BPB medium as well as the production of D-gluconic acid were determined in their culture. Presence of two of the genes encoding the cofactor PQQ of GDH enzyme was analyzed in the genome of this bacterial collection. 16S rDNA sequence analysis indicated that isolates belong to genera Serratia, Enterobacter, Pantoea, Acinetobacter, Bacillus and Enterococcus. All bacteria showed ability to solubilize tricalcium phosphate either in unbuffered or buffered medium. Nevertheless, addition of buffer solutions reduced levels of Pi liberated by the isolates. Although almost all isolates produced detectable amounts of D-gluconic acid, no correlation with levels of P soluble released were observed. The presence of pqqE and pqqC genes was detected only in Gram negative bacteria. It was concluded from this study that the mechanism involved in phosphate solubilization is organic acids production and, presence of pqq genes in all Gram negative bacteria analyzed encourages to confirm their role in bacterial phosphate solubilizing ability as well to identify genes involved in this PGP trait in Gram positive bacteria.

The calcium silicate/alginate composite: Preparation and evaluation of its behavior as bioactive injectable hydrogels

In this study, an injectable calcium silicate (CS)/sodium alginate (SA) hybrid hydrogel was prepared using a novel material composition design. CS was incorporated into an alginate solution and internal in situ gelling was induced by the calcium ions directly released from CS with the addition of d-gluconic acid δ-lactone (GDL). The gelling time could be controlled, from about 30s to 10min, by varying the amounts of CS and GDL added. The mechanical properties of the hydrogels with different amounts of CS and GDL were systematically analyzed. The compressive strength of 5% CS/SA hydrogels was higher than that of 10% CS/SA for the same amount of GDL. The swelling behaviors of 5% CS/SA hydrogels with different contents of GDL were therefore investigated. The swelling ratios of the hydrogels decreased with increasing GDL, and 5% CS/SA hydrogel with 1% GDL swelled by only less than 5%. Scanning electron microscopy (SEM) observation of the scaffolds showed an optimal interconnected porous structure, with the pore size ranging between 50 and 200μm. Fourier transform infrared spectroscopy and SEM showed that the CS/SA composite hydrogel induced the formation of hydroxyapatite on the surface of the materials in simulated body fluid. In addition, rat bone mesenchymal stem cells (rtBMSCs) cultured in the presence of hydrogels and their ionic extracts were able to maintain the viability and proliferation. Furthermore, the CS/SA composite hydrogel and its ionic extracts stimulated rtBMSCs to produce alkaline phosphatase, and its ionic extracts could also promote angiogenesis of human umbilical vein endothelial cells. Overall, all these results indicate that the CS/SA composite hydrogel efficiently supported the adhesion, proliferation and differentiation of osteogenic and angiogenic cells. Together with its porous three-dimensional structure and injectable properties, CS/SA composite hydrogel possesses great potential for bone regeneration and tissue engineering applications.

Physico-kinetic and functional features of a novel β-glucosidase isolated from milk thistle (Silybum marianum Gaertn.) flower petals

A highly abundant β-glucosidase from petals of Silybum marianum has been purified and characterized for its physico-kinetic properties. The 135 kDa enzyme was a homodimer with subunit molecular mass of 67.6 kDa. The characteristic catalytic properties of the enzyme included acidic pH optimum (5.5), meso-thermostability, and β-linked substrate specificity with preference for gluco-conjugate but a marked (>50 %) activity with D-fuco-conjugates and considerable (~16 %) activity towards D-galacto-conjugates. The enzyme showed high affinity for p-nitrophenyl glucoside (pNPG) with Km and Vmax values of 0.25 mM and 5.35 μkat.mg−1 enzyme protein. Thus, the enzyme had a very high (292,000 M−1.s−1) catalytic efficiency (Kcat/Km). Thermal catalytic optimum of enzyme was 40 °C with activation energy value 8.26 kCal.Mol−1. The enzyme showed significant insensitivity to D-gluconic acid lactone inhibition (57 % at 5 mM) with an apparent Ki 3.8 mM. The transglucosylating ability of enzyme was noticed for glucosylation of geraniol and withaferin-A with pNPG as glucosyl donor but cellobiose did not serve as the glycosyl donor. Partial proteomics of the enzyme revealed two peptide fragment sequences, VTPSNEVH and KRSEESNF. These motifs showed significant matching/sequence conservation with some other glycohydrolases. The novelties of purified enzyme hold potential to expand a library of catalytically characteristic members of the hydrolase family from plants for use in biotransformation applications.

Simultaneous determination of glucose, d-gluconic, 2-keto-d-gluconic and 5-keto-d-gluconic acids by ion chromatography-pulsed amperometric detection with column-switching technique

A simple ion chromatographic (IC) method for simultaneous determination of glucose, d-gluconic acid (DGA), 2-keto-d-gluconic acid (2-KDG) and 5-keto d-gluconic acid (5-KDG) was proposed, with pulsed amperometric detection (PAD) and column-switching technique. Using this technique, the four compounds were detected simultaneously in a short time with strongly retained compounds (2-KDG and 5-KDG) eluted out prior to weakly retained compounds (glucose and DGA). Under the optimized conditions, the method showed good linearity in the range of 0.01–20mgL−1 with determination coefficients (R2)≥99.84%. Low detection limits (LODs) in the range of 0.87–2.59μgL−1 and good repeatability (RSD<3%, n=6) were obtained. The proposed method has been successfully applied to the analysis of the four compounds in the fermentation broth, in which Gluconobacter oxydans was used to produce gluconic acids from glucose.

Cloning, expression and characterization of an ethanol tolerant GH3 β-glucosidase fromMyceliophthora thermophila

The β-glucosidase gene bgl3a from Myceliophthora thermophila, member of the fungal glycosyl hydrolase (GH) family 3, was cloned and expressed in Pichia pastoris. The mature β-glucosidase gene, which results after the excision of one intron and the secreting signal peptide, was placed under the control of the strong alcohol oxidase promoter (AOX1) in the plasmid pPICZαC. The recombinant enzyme (90 kDa) was purified and characterized in order to evaluate its biotechnological potential. Recombinant P. pastoris efficiently secreted β-glucosidase into the medium and produced high level of enzymatic activity (41 U/ml) after 192 h of growth, under methanol induction. MtBgl3a was able to hydrolyze low molecular weight substrates and polysaccharides containing β-glucosidic residues. The Km was found to be 0.39 mM on p-β-NPG and 2.64 mM on cellobiose. Optimal pH and temperature for the p-β-NPG hydrolysis were 5.0 and 70 °C. The β-glucosidase exhibits a half life of 143 min at 60 °C. Kinetic parameters of inhibition were determined for D-glucose, D-xylose and D-gluconic acid, indicating tolerance of the enzyme for these sugars and oxidized products. The recombinant enzyme was stimulated by short chain alcohols and has been shown to efficiently synthesize methyl-D-glucoside in the presence of methanol due to its transglycosylation activity. The stability of MtBgl3a in ethanol was prominent, and it retained most of its original activity after we exposed it to 50% ethanol for 6 h. The high catalytic performance, good thermal stability and tolerance to elevated concentrations of ethanol, D-xylose and D-glucose qualify this enzyme for use in the hydrolysis of lignocellulosic biomass for biofuel production, as part of an efficient complete multi-enzyme cocktail.

Low pH d-xylonate production with Pichia kudriavzevii

d-Xylonic acid is one of the top 30 most desirable chemicals to be derived from biomass sugars identified by the US Department of Energy, being applicable as a non-food substitute for d-gluconic acid and as a platform chemical. We engineered the non-conventional yeast Pichia kudriavzevii VTT C-79090T to express a d-xylose dehydrogenase coding gene from Caulobacter crescentus. With this single modification the recombinant P. kudriavzevii strain produced up to 171gL−1 of d-xylonate from 171gL−1d-xylose at a rate of 1.4gL−1h−1 and yield of 1.0g [g substrate consumed]−1, which was comparable with d-xylonate production by Gluconobacter oxydans or Pseudomonas sp. The productivity of the strain was also remarkable at low pH, producing 146gL−1d-xylonate at 1.2gL−1h−1 at pH 3.0. This is the best low pH production reported for d-xylonate. These results encourage further development towards industrial scale production.

A Novel Chemical Solution to Demineralize Valvular and Coronary Calcification: Insights from Yogurt and Honey

Objectives: The purpose of the study is to evaluate the demineralizing efficacy of combined L(+) Lactic Acid And D-Gluconic Acid (LAGA) solution and combined yogurt and honey on human specimens of calcific valves and coronaries retrieved from patients who underwent aortic valve replacement, mitral valve replacement and heart transplantation. Background: Cardiovascular calcification is a major health problem in the aging population and hence, the need for therapeutic strategies to attenuate the disease process. Methods: Serial sections of 4 Formalin Fixed Paraffin Embedded (FFPE) calcific aortic valves, 4 calcific mitral valves and 12 coronary arteries were treated with LAGA solution. Von Kossa silver staining was used for histological semiquantitative evaluation of extent of calcification. A direct treatment of the tissue specimens with combined yogurt and honey was also performed. Results: A complete dissolution of the calcification was noted in all the aortic, mitral and coronary specimens after treatment with LAGA solution (P<0.0001). A direct treatment of the aortic, mitral, and coronary specimens with combined yogurt and honey for 24 hours showed mild reduction in the degree of calcification by at least one grade that was statistically significant (P<0.01). Conclusions: LAGA solution is efficacious in demineralizing calcific aortic and mitral valves and calcific coronary arteries. Combined yogurt and honey result in mild reduction in calcification. Our study may pave the way for epidemiological studies and potential therapeutic strategies to treat patients with vascular calcification.

Evaluation of the food grade expression systems NICE and pSIP for the production of 2,5-diketo-D-gluconic acid reductase from Corynebacterium glutamicum

2,5-diketo-D-gluconic acid reductase (2,5-DKG reductase) catalyses the reduction of 2,5-diketo-D-gluconic acid (2,5-DKG) to 2-keto-L-gulonic acid (2-KLG), a direct precursor (lactone) of L-ascorbic acid (vitamin C). This reaction is an essential step in the biocatalytic production of the food supplement vitamin C from D-glucose or D-gluconic acid. As 2,5-DKG reductase is usually produced recombinantly, it is of interest to establish an efficient process for 2,5-DKG reductase production that also satisfies food safety requirements. In the present study, three recently described food grade variants of the Lactobacillales based expression systems pSIP (Lactobacillus plantarum) and NICE (Lactococcus lactis) were evaluated with regard to their effictiveness to produce 2,5-DKG reductase from Corynebacterium glutamicum. Our results indicate that both systems are suitable for 2,5-DKG reductase expression. Maximum production yields were obtained with Lb. plantarum/pSIP609 by pH control at 6.5. With 262 U per litre of broth, this represents the highest heterologous expression level so far reported for 2,5-DKG reductase from C. glutamicum. Accordingly, Lb. plantarum/pSIP609 might be an interesting alternative to Escherichia coli expression systems for industrial 2,5-DKG reductase production.