Engineering an aldehyde dehydrogenase toward its substrates, 3-hydroxypropanal and NAD(+), for enhancing the production of 3-hydroxypropionic acid

3-Hydroxypropionic acid (3-HP) can be produced via the biological route involving two enzymatic reactions: dehydration of glycerol to 3-hydroxypropanal (3-HPA) and then oxidation to 3-HP. However, commercial production of 3-HP using recombinant microorganisms has been hampered with several problems, some of which are associated with the toxicity of 3-HPA and the efficiency of NAD(+) regeneration. We engineered a-ketoglutaric semialdehyde dehydrogenase (KGSADH) from Azospirillum brasilense for the second reaction to address these issues. The residues in the binding sites for the substrates, 3-HPA and NAD(+), were randomized, and the resulting libraries were screened for higher activity. Isolated KGSADH variants had significantly lower Km values for both the substrates. The enzymes also showed higher substrate specificities for aldehyde and NAD(+), less inhibition by NADH, and greater resistance to inactivation by 3-HPA than the wild-type enzyme. A recombinant Pseudomonas denitrificans strain with one of the engineered KGSADH variants exhibited less accumulation of 3-HPA, decreased levels of inactivation of the enzymes, and higher cell growth than that with the wild-type KGSADH. The flask culture of the P. denitrificans strain with the mutant KGSADH resulted in about 40% increase of 3-HP titer (53 mM) compared with that using the wild-type enzyme (37 mM)

Metal release from contaminated estuarine sediment under pH changes in the marine environment

The contaminant release from estuarine sediment due to pH changes was investigated using a modified CEN/TS 14429 pH-dependence leaching test. The test is performed in the range of pH values of 0-14 using deionised water and seawater as leaching solutions. The experimental conditions mimic different circumstances of the marine environment due to the global acidification, carbon dioxide (CO2) leakages from carbon capture and sequestration technologies, and accidental chemical spills in seawater. Leaching test results using seawater as leaching solution show a better neutralisation capacity giving slightly lower metal leaching concentrations than when using deionised water. The contaminated sediment shows a low base-neutralisation capacity (BNCpH 12 = -0.44 eq/kg for deionised water and BNCpH 12 = -1.38 eq/kg for seawater) but a high acid-neutralisation capacity when using deionised water (ANCpH 4 = 3.58 eq/ kg) and seawater (ANCpH 4 = 3.97 eq/kg). Experimental results are modelled with the Visual MINTEQ geochemical software to predict metal release from sediment using both leaching liquids. Surface adsorption to iron- and aluminium- (hydr)oxides was applied for all studied elements. The consideration of the metal-organic matter binding through the NICA-Donnan model and Stockholm Humic Model for lead and copper, respectively, improves the former metal release prediction. Modelled curves can be useful for the environmental impact assessment of seawater acidification due to its match with the experimental values.This work was supported by the Spanish Ministry of Economy and Competitiveness, Project No. CTM 2011-28437-C02-01, ERDF included. M. C. Martı´n-Torre was funded by the Spanish Ministry of Economy and Competitiveness by means of FPI. Fellowship No. BES-2012-053816

BMC Public Health

BACKGROUND: In 2009, the World Health Organization's Commission on Social Determinants of Health set out its recommendations for action, which included establishing equity from early childhood onwards by enabling all children and their mothers to benefit from a comprehensive package of quality programmes. In order to address social inequalities in health, it is recommended that action be taken from early childhood, and actions providing support for parenting are an effective lever in this respect. The aim of this review of systematic reviews is to analyse, on the one hand, the components and characteristics of effective interventions in parenting support and, on the other, the extent to which the reviews took into account social inequalities in health. METHODS: A total of 796 reviews were selected from peer-reviewed journals published between 2009 and 2016 in French or English. Of these, 21 reviews responding to the AMSTAR and selected ROBIS criteria were retained. These were analysed in relation to the consideration they gave to social inequalities in health according to PRISMA-equity. RESULTS: The reviews confirmed that parenting support programmes improved infants' sleep, increased mothers' self-esteem and reduced mothers' anger, anxiety and stress levels. The mainly authors noted that the contexts in which the interventions had taken place were described either scantly or not at all, making it difficult to evaluate them. Only half of the reviews had addressed the question of social inequalities in health. In particular, there had been little research conducted on the relational aspect and the social link. CONCLUSION: In terms of addressing social inequalities in perinatal health, the approach remains both modest and reductive. Understanding how, for whom and in what conditions interventions operate is one way of optimising their results. Further research is needed to study the interactions between the interventions and their contexts

Micronutrient needs of tropical food crops

The trace element requirements of tropical crops are reviewed with special reference to their role, the differences between crop species, the differences between cultivars, paths of trace element uptake, effects of climate, the importance of crop management and yield levels

Occurrence of the Asn45Ser mutation in the GPIX gene in a Belgian patient with Bernard Soulier syndrome

Bernard Soulier Syndrome (BSS) is a rare inherited bleeding disorder caused by a defect in the glycoprotein (GP)Ib/IX/V complex. A patient with a bleeding problem was diagnosed as having BSS based on the prolonged bleeding time, the absence of ristocetin induced platelet aggregations, thrombocytopenia and the presence of giant platelets. Analysis of the platelets of the propositus, a 39-year-old Belgian female, by flow cytometry revealed a decreased expression of the GPIb/IX polypeptides. Western blotting confirmed these results and showed moreover that there was a decreased disulfide bridge formation between GPIb alpha and GPIb beta. After sequence analysis of the GPIb alpha, GPIb beta and GPIX genes, only a mutation in the GPIX gene at position 1826 (A-->G) was identified, changing Asn45-->Ser. Restriction analysis with Fnu4H1 demonstrated that the patient was homozygous for this mutation. As this Asn45-->Ser mutation in the GPIX gene was already found in four unrelated families, i.e. in a British, Austrian, Swedish and Finnish one, the occurrence of this mutation in a Belgian patient supports the hypothesis of Koskela et al. (1999) that the Asn45Ser mutation in GPIX appears to be an ancient mutation shared by northern and central European populations. Our present observation of a decreased disulfide bridge formation between GPIb alpha and GPIb beta shows that GPIX is not only needed for the correct assembly of the complex but might also be needed for the disulfide bridge formation between GPIb alpha and GPIb beta.status: publishe