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.
Vinogradov E, Li J, Sadovskaya I, Jabbouri S, Helander IM
Carbohydrate research •
The structure of the carbohydrate backbone of the lipopolysaccharide from Pectinatus frisingensis strain VTT E-79104 was analyzed using chemical degradations, NMR spectroscopy, mass spectrometry, and chemical methods. The LPS contains two major structural variants, differing in the presence or absence of an octasaccharide fragment. The largest structure of the carbohydrate backbone of the LPS, that could be deduced from experimental results, consists of 20 monosaccharides arranged in a nonrepetitive sequence: [carbohydrate structure: see text] where R is H or 4-O-Me-alpha-L-Fuc-(1-2)-4-O-Me-beta-Hep-(1-3)-alpha-GlcNAc-(1-2)-beta-Man-(1-3)-beta-ManNAc-(1-4)-alpha-Gal-(1-4)-beta-Hep-(1-3)-beta-GalNAc-(1- where Hep is a residue of D-glycero-D-galacto-heptose; all monosaccharides have the D-configuration except for 4-O-Me-L-Fuc and L-Ara4N. This structure is architecturally similar to the oligosaccharide system reported previously in P. frisingensis VTT E-82164 LPS, but differs from the latter in composition and also in the size of the outer region.
Yeast strains producing alpha-galactosidase (alpha Gal) are able to use melibiose as a carbon source during growth or fermentation. We cloned a MEL gene from Saccharomyces carlsbergensis NCYC396 through hybridization to the MEL1 gene cloned earlier from Saccharomyces cerevisiae var. uvarum. The alpha Gal encoded by the newly cloned gene was galactose-inducible as is the alpha Gal encoded by MEL1. A probable GAL4-protein recognition sequence was found in the upstream region of the NCYC396 MEL gene. The gene was transcribed to a 1.5-kb mRNA which, according to the nucleotide sequence, encodes a protein of 471 amino acids (aa) with an Mr of 52,006. The first 18 aa fulfilled the criteria for the signal sequence, but lacked positively charged aa residues, except the initiating methionine. The enzyme activity was found exclusively in the cellular fraction of the cultures. The deduced aa sequence was compared to the aa sequences of other alpha Gal enzymes. It showed 83% identity with the S. cerevisiae enzyme, but only 35% with the plant enzyme, 30% with the human enzyme and 17% with the Escherichia coli enzyme. With pulsed-field electrophoresis, the MEL gene was located on chromosome X of S. carlsbergensis, whereas the S. cerevisiae var. uvarum MEL1 gene is located on chromosome II.
The binding of a panel of blood group-reactive lectins to frozen sections of human kidney was studied with a special emphasis on reactivity with endothelia and basement membranes. The blood group A-reactive lectins, all specific for alpha-D-N-acetylgalactosamine (GalNAc), Helix aspersa (HAA), Helix pomatia (HPA), and Griffonia simplicifolia I-A4 (GSA-I-A4) agglutinins bound to the endothelium in specimens with blood groups A and AB. In other samples, these lectins reacted predominantly with tubular basement membranes, as well as with certain tubules. Both Dolichos biflorus (DBA) and Vicia villosa agglutinins (VVA), reported to react with blood group A1 substance, failed to reveal endothelia in most specimens, but bound differently to tubules in all blood groups. The blood group B-reactive lectins, specific for alpha-D-galactose (alpha-Gal) or GalNAc, respectively, GSA-I-B4 and Sophora japonica agglutinin (SJA), bound to the endothelia in specimens from blood group B or AB and in other specimens bound only to certain tubules. Among the blood group O-reactive lectins, specific for alpha-L-fucose (Fuc), Ulex europaeus I agglutinin (UEA-I) conjugates, but not other lectins with a similar nominal specificity, bound strongly to endothelia in specimens with blood group O. The UEA-I conjugates bound distinctly more faintly to endothelia in specimens of other blood groups. The present results indicate that lectins, binding to defined blood group determinants, react with endothelia in specimens of the respective blood group status. Furthermore, they suggest that basement membranes and some tubules in the human kidney show a distinct heterogeneity in their expression of saccharide residues, related to their blood group status.
A battery of fluorochrome- or peroxidase-coupled lectins, reacting with alpha- or beta-galactose (Gal), terminal N-acetylgalactosamine (GalNAc), or Gal-(beta 1-3)-GalNAc residues, was used to study the emergence and distribution of cellular glycoconjugates in developing and adult rat glomeruli. Neuraminidase pretreatment of the specimens was applied to monitor the maturation of the glomerular sialoglycoprotein coat. In the adult glomeruli, the lectin conjugates applied reacted sparsely or not at all, but most of them showed an increased reactivity with podocytes and/or the glomerular basement membrane after neuraminidase treatment. In the embryonic glomeruli, lectins reacting with beta-Gal residues prominently bound to the basement membranes, as revealed in double-staining with laminin antibodies. This reactivity decreased first during late postnatal development. Some terminal Gal-(beta 1-3)-GalNAc residues were noted in the earliest podocytes, but obviously soon became covered by sialylation. Furthermore, the developing podocytes prominently displayed alpha-Gal residues, as marked by Maclura pomifera (MPA) and Jacalin reactivities but not by the GSA-I conjugates. During postnatal maturation these reactivities also decreased. The GalNAc-specific Helix pomatia (HPA) and Helix aspersa (HAA) agglutinins bound to basement membranes of evolving podocytes but later revealed in the podocytes only a Golgi-like cytoplasmic reactivity. These two lectins showed a marked difference in their binding to tubular basement membranes. In lectin blotting experiments of electrophoretically separated polypeptides transferred onto nitrocellulose, the peanut agglutinin (PNA) and MPA conjugates revealed upon neuraminidase treatment a broad Mr 140,000 polypeptide, compatible with podocalyxin, both in isolated developing and adult glomeruli. The MPA conjugate revealed a similar polypeptide in developing glomeruli, even without neuraminidase treatment. Similar experiments with the HPA and HAA conjugates revealed different polypeptides in both adult and developing glomeruli. Obviously, in the rat kidney the maturation of the podocyte sialoglycoprotein coat and the glomerular basement membranes are multiphasic processes that continue even during late postnatal development.
Expression of glycoconjugates during transfilter-induced differentiation of metanephric mesenchyme was studied by using fluorochrome- and peroxidase-coupled lectins. All cells in the uninduced metanephric mesenchyme expressed mannose, beta-D-galactose (beta-Gal), N-acetylglucosamine (GlucNAc), and terminal sialic acids. Additionally, solitary cells showed terminal alpha-D-galactose alpha-D-galactose (alpha-Gal) typical of mouse endothelial cells. During culture, undifferentiated mesenchymal cells seemed to disappear from induced explants, and many of the stromal cells between the evolving tubules presented terminal alpha-Gal residues. Similar positivity could be revealed in monolayer cultures of induced mesenchymes. A number of tubules in induced explants displayed alpha-L-fucosyl (Fuc) residues, characteristic of mature proximal tubules. Some terminal Ga1NAc residues, recognized only by Dolichos biflorus agglutinin, emerged in a few tubular cells after prolonged culture. The early tubules and glomerular bodies displayed a basement membrane presenting both terminal Ga1-(beta 1-3)-Ga1NAc and Ga1NAc residues. These positivities disappeared later from many tubular structures and glomerular bodies but persisted in tubules expressing proximal tubular differentiation. The glomerular bodies displayed only one cell type, reminiscent of maturing podocytes, presenting terminal Ga1-(beta 1-3)-Ga1NAc and Ga1NAc residues. Later these saccharide residues became covered by sialylation, as they could then be revealed only after treatment with neuraminidase. The results indicate that the segment-specific expression of saccharide residues during differentiation of nephron in vitro resembles the sequence seen in vivo. This study also suggests that the basement membranes surrounding the nephron show a stepwise, segment-specific maturation. Despite the presence of endothelial cells in the metanephric explants, only avascular glomeruli evolved in this differentiation model.
