Høyer A, Christensen JJ, Arnesen EK, Andersen R, Eneroth H, et al.
Food & nutrition research •
As part of the process of updating national dietary reference values (DRVs) and food-based dietary guidelines (FBDGs), the Nordic Nutrition Recommendations 2022 project (NNR2022) will select a limited number of topics for systematic reviews (SRs). To develop and transparently describe the results of a procedure for prioritisation of topics that may be submitted for SRs in the NNR2022 project. In an open call, scientists, health professionals, national food and health authorities, food manufacturers, other stakeholders and the general population in the Nordic and Baltic countries were invited to suggest SR topics. The NNR2022 Committee developed scoping reviews (ScRs) for 51 nutrients and food groups aimed at identifying potential SR topics. These ScRs included the relevant nominations from the open call. SR topics were categorised, ranked and prioritised by the NNR2022 Committee in a modified Delphi process. Existing qualified SRs were identified to omit duplication. A total of 45 nominations with suggestion for more than 200 exposure-outcome pairs were received in the public call. A number of additional topics were identified in ScRs. In order to omit duplication with recently qualified SRs, we defined criteria and identified 76 qualified SRs. The NNR2022 Committee subsequently shortlisted 52 PI/ECOTSS statements, none of which overlapped with the qualified SRs. The PI/ECOTSS statements were then graded 'High' ( = 21), 'Medium' ( = 9) or 'Low' ( = 22) importance, and the PI/ECOTSS statements with 'High' were ranked in a Delphi process. The nine top prioritised PI/ECOTSS included the following exposure-outcome pairs: 1) plant protein intake in children and body growth, 2) pulses/legumes intake, and cardiovascular disease and type 2 diabetes, 3) plant protein intake in adults, and atherosclerotic/cardiovascular disease and type 2 diabetes, 4) fat quality and mental health, 5) vitamin B and vitamin B status, 6) intake of white meat (no consumption vs. high consumption and white meat replaced with red meat), and all-cause mortality, type 2 diabetes and risk factors, 7) intake of n-3 LPUFAs from supplements during pregnancy, and asthma and allergies in the offspring, 8) nuts intake and cardiovascular disease (CVD) and type 2 diabetes in adults, 9) dietary fibre intake (high vs. low) in children and bowel function. The selection of topics for SRs is central in the NNR2022 project, as the results of these SRs may cause adjustment of existing DRVs and FBDGs. That is why we have developed this extensive process for the prioritisation of SR topics. For transparency, the results of the process are reported in this publication. The principles and methodologies developed in the NNR2022 project may serve as a framework for national health authorities or organisations when developing national DRVs and FBDGs. This collaboration between the food and health authorities in Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway and Sweden represents an international effort for harmonisation and sharing of resources and competence when developing national DRVs and FBDGs.
Wold CW, Kjeldsen C, Corthay A, Rise F, Christensen BE, et al.
Carbohydrate polymers •
The aim of this paper was to perform a comprehensive characterization of polysaccharides isolated from the interior (IOI) and exterior (IOE) parts of the fungus Inonotus obliquus. Pre-extraction with DCM and MeOH, followed by water and alkali extraction and ethanol precipitation gave two water extracts and two alkali extracts. Neutral and acidic polysaccharide fractions were obtained after anion-exchange chromatography of the water extracts. The neutral polysaccharides (60-73 kDa) were heterogeneous and branched and consisted of a (1 → 3)-linked β-Glc backbone with (1 → 6)-linked kinks in the chain at approximately every fifth residue, with branches of (1 → 6)-linked β-Glc in addition to substantial amounts of (1 → 6)-linked α-Gal with 3-O-methylation at about every third Gal residue. The acidic polysaccharide fractions (10-31 kDa) showed similar structural motifs as the neutral fractions differing mainly by the presence of (1 → 4)-linked α-GalA and α-GlcA. β-Xyl, α-Man and α-Rha were also present in varying amounts in all fractions. No major structural differences between the IOI and IOE fractions were observed. An alkaline polysaccharide fraction (>450 kDa) was obtained from the IOI alkali extract, and consisted mainly of (1 → 3)- and (1 → 6)-linked β-Glc and (1 → 4)-linked β-Xyl. Several of the fractions showed in vitro immunomodulatory effect by increasing NO production in the murine macrophage and dendritic cell lines J774.A1 and D2SC/1. Most fractions managed to increase NO production only at the highest concentration tested (100 μg/ml), while the neutral fraction IOE-WN activated potent NO production at 10 μg/ml and was considered the most promising immunomodulating fraction in this study.
Lactobacillus acidophilus NCFM is a probiotic bacterium known for its beneficial effects on human health. The importance of α-galactosidases (α-Gals) for growth of probiotic organisms on oligosaccharides of the raffinose family present in many foods is increasingly recognized. Here, the crystal structure of α-Gal from L. acidophilus NCFM (LaMel36A) of glycoside hydrolase (GH) family 36 (GH36) is determined by single-wavelength anomalous dispersion. In addition, a 1.58-Å-resolution crystallographic complex with α-d-galactose at substrate binding subsite -1 was determined. LaMel36A has a large N-terminal twisted β-sandwich domain, connected by a long α-helix to the catalytic (β/α)(8)-barrel domain, and a C-terminal β-sheet domain. Four identical monomers form a tightly packed tetramer where three monomers contribute to the structural integrity of the active site in each monomer. Structural comparison of LaMel36A with the monomeric Thermotoga maritima α-Gal (TmGal36A) reveals that O2 of α-d-galactose in LaMel36A interacts with a backbone nitrogen in a glycine-rich loop of the catalytic domain, whereas the corresponding atom in TmGal36A is from a tryptophan side chain belonging to the N-terminal domain. Thus, two distinctly different structural motifs participate in substrate recognition. The tetrameric LaMel36A furthermore has a much deeper active site than the monomeric TmGal36A, which possibly modulates substrate specificity. Sequence analysis of GH36, inspired by the observed structural differences, results in four distinct subgroups having clearly different active-site sequence motifs. This novel subdivision incorporates functional and architectural features and may aid further biochemical and structural analyses within GH36.
