Optimization of the dilute maleic acid pretreatment of wheat straw

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Folate reference interval estimation in the Dutch general population

Background: Folate functions as an enzyme co-factor within the one-carbon metabolic pathway, providing key metabolites required for DNA synthesis and methylation. Hence, insufficient intake of folate can negatively affect health. As correct interpretation of folate status is dependent on a well-established reference interval, we set out to perform a new estimation following the restandardization of the Roche folate assay against the international folate standard. Materials and methods: The folate reference interval was estimated using samples obtained from the Dutch population-based Lifelines cohort. The reference interval was estimated using two methods: a nonparametric estimation combined with bootstrap resampling and by fitting the data to a gamma distribution. The lower reference limit was verified in a patient cohort by combined measurement of folate and homocysteine. Results: Dependent on the method used for estimation and in- or exclusion of individuals younger than 21 years of age, the lower reference limit ranged from 6.8 to 7.3 nmol/L and the upper reference limit ranged from 26 to 38.5 nmol/L. Applying a lower reference limit of 7.3 nmol/L resulted in the following percentage of folate deficiencies over a period of 12 months: general practitioner 15.5% (IQR 4.0%), general hospital 12.8% (IQR 5.3%), academic hospital 9.6% (IQR 4.3%). Conclusions: We estimated the folate reference interval in the Dutch general population which is not affected by a folic acid fortification program and verified the obtained lower reference limit by homocysteine measurements. Based on our results, we propose a folate reference interval independent of age of 7.3-38.5 nmol/

Identification of a new genotype of Torque Teno Mini virus

Although human torque teno viruses (TTVs) were first discovered in 1997, still many associated aspects are not clarified yet. The viruses reveal a remarkable heterogeneity and it is possible that some genotypes are more pathogenic than others. The identification of all genotypes is essential to confirm previous pathogenicity data, and an unbiased search for novel viruses is needed to identify TTVs that might be related to disease. The virus discovery technique VIDISCA-454 was used to screen serum of 55 HIV-1 positive injecting drug users, from the Amsterdam Cohort Studies, in search for novel blood-blood transmittable viruses which are undetectable via normal diagnostics or panvirus-primer PCRs. A novel torque teno mini virus (TTMV) was identified in two patients and the sequence of the full genomes were determined. The virus is significantly different from the known TTMVs ( <40% amino acid identity in ORF1), yet it contains conserved characteristics that are also present in other TTMVs. The virus is chronically present in both patients, and these patients both suffered from a pneumococcal pneumonia during follow up and had extremely low B-cells counts. We describe a novel TTMV which we tentatively named TTMV-13. Further research is needed to address the epidemiology and pathogenicity of this novel viru

Dissolution of phosphate from pig manure ash using organic and mineral acids

Phosphate fertilizer production from renewable resources like sewage sludge and livestock waste helps to ensure future phosphate supply, while also solving waste management issues. After combustion, the resulting ash contains heavy metals at a restrictively high level, preventing its direct use as fertilizer. In this study, several organic acids and sulfuric acid are used to dissolve phosphates from ash. Acetic, maleic and citric acids perform as expected, but oxalic acid outperforms all, including sulfuric acid. All phosphate is dissolved at pH 4 when using oxalic acid, while pH 2 is needed in the case of sulfuric acid. Furthermore, less of the heavy metals end up in the resulting solution when using oxalic acid. Nearly all calcium is retrieved in the solid residue when oxalic acid is used, pointing towards formation of calcium oxalate, not chelating complexes as often assumed, as the cause of oxalic acid outperforming the other acids in this study

The hepatitis B virus x protein inhibits thymine DNA glycosylase initiated base excision repair.

The hepatitis B virus (HBV) genome encodes the X protein (HBx), a ubiquitous transactivator that is required for HBV replication. Expression of the HBx protein has been associated with the development of HBV infection-related hepatocellular carcinoma (HCC). Previously, we generated a 3D structure of HBx by combined homology and ab initio in silico modelling. This structure showed a striking similarity to the human thymine DNA glycosylase (TDG), a key enzyme in the base excision repair (BER) pathway. To further explore this finding, we investigated whether both proteins interfere with or complement each other's functions. Here we show that TDG does not affect HBV replication, but that HBx strongly inhibits TDG-initiated base excision repair (BER), a major DNA repair pathway. Inhibition of the BER pathway may contribute substantially to the oncogenic effect of HBV infection

Protein X of hepatitis B virus: origin and structure similarity with the central domain of DNA glycosylase.

Orthohepadnavirus (mammalian hosts) and avihepadnavirus (avian hosts) constitute the family of Hepadnaviridae and differ by their capability and inability for expression of protein X, respectively. Origin and functions of X are unclear. The evolutionary analysis at issue of X indicates that present strains of orthohepadnavirus started to diverge about 25,000 years ago, simultaneously with the onset of avihepadnavirus diversification. These evolutionary events were preceded by a much longer period during which orthohepadnavirus developed a functional protein X while avihepadnavirus evolved without X. An in silico generated 3D-model of orthohepadnaviral X protein displayed considerable similarity to the tertiary structure of DNA glycosylases (key enzymes of base excision DNA repair pathways). Similarity is confined to the central domain of MUG proteins with the typical DNA-binding facilities but without the capability of DNA glycosylase enzymatic activity. The hypothetical translation product of a vestigial X reading frame in the genome of duck hepadnavirus could also been folded into a DNA glycosylase-like 3D-structure. In conclusion, the most recent common ancestor of ortho- and avihepadnavirus carried an X sequence with orthology to the central domain of DNA glycosylase

Base excision repair is inhibited by HBx.

<p>The effect of HBx and TDG on BER activity is given as the ratio between the luciferase activity of pG/T (mismatch) and pG/C (positive control) vectors after subtraction of the activity of the pA/T (negative control) vector. The activity of the pG/T vector was significantly less than the activity of the positive control, while co-transfection of pMyc-TDG restored the activity of the pG/T mismatch vector. Co-transfection of pHSV-HBx resulted in a reduction of BER activity, regardless of cotransfection of pMyc-TDG. Each bar depicts the mean and SEM of four measurements. DNA concentrations are expressed as ng/ml. EV: empty control vector. (B) Myc-TDG and HSV-HBx expression in HEK 293T cells was confirmed by Western blotting. *p<0.05, **p<0.01.</p

Replication of HBV X^- is rescued by co-expression of HBx but not TDG.

<p>(<b>A</b>) HepG2 cells were transfected with the R9 or R9ΔX vector to induce HBV replication in the presence (HBV) or absence (HBV X⁻) of HBx. (<b>B</b>) Addition of lamivudine to the cultures inhibited production of capsid-associated HBV DNA, indicating selective amplification of progeny DNA (<b>C</b>) Production of capsid-associated HBV DNA by R9ΔX was restored to wild-type levels by co-transfection of pHSV-HBx. (<b>D</b>) Co-expression of Myc-TDG does not affect HBV replication regardless of the presence of HBx. The average and standard deviation of the HBV DNA copy number of seven independent experiments is given. *p<0.05, **p<0.01. Significance was determined with a two-sided student’s T test.</p

Folate reference interval estimation in the Dutch general population

Background: Folate functions as an enzyme co-factor within the one-carbon metabolic pathway, providing key metabolites required for DNA synthesis and methylation. Hence, insufficient intake of folate can negatively affect health. As correct interpretation of folate status is dependent on a well-established reference interval, we set out to perform a new estimation following the restandardization of the Roche folate assay against the international folate standard. Materials and methods: The folate reference interval was estimated using samples obtained from the Dutch population-based Lifelines cohort. The reference interval was estimated using two methods: a nonparametric estimation combined with bootstrap resampling and by fitting the data to a gamma distribution. The lower reference limit was verified in a patient cohort by combined measurement of folate and homocysteine. Results: Dependent on the method used for estimation and in- or exclusion of individuals younger than 21 years of age, the lower reference limit ranged from 6.8 to 7.3 nmol/L and the upper reference limit ranged from 26 to 38.5 nmol/L. Applying a lower reference limit of 7.3 nmol/L resulted in the following percentage of folate deficiencies over a period of 12 months: general practitioner 15.5% (IQR 4.0%), general hospital 12.8% (IQR 5.3%), academic hospital 9.6% (IQR 4.3%). Conclusions: We estimated the folate reference interval in the Dutch general population which is not affected by a folic acid fortification program and verified the obtained lower reference limit by homocysteine measurements. Based on our results, we propose a folate reference interval independent of age of 7.3-38.5 nmol/