Several studies have suggested that the host genetics may influence the composition of gut microbiota, but few genes involved in host control have been proposed (Sekirov et al., 2010). Lipocalin 2 (Lcn2) prevents growth of bacteria that rely on catechol type siderophores for iron acquisition (Goetz, et al., 2003; Flo, et al., 2004). It was hypothesized that Lcn2 may impart a selection pressure on establishment of the gut microbiota and thus influence the commensal diversity. The aim of this study was to find out whether the antimicrobial protein, Lipocalin 2, has a determining effect on the colonization of the gut microbiota in mice. Two factors were investigated: genotype (Wt, Ht and Lcn2 KO) and habitation (single-housing and co-housing). The naturally developing gut microbiota of wild type mice (Wt), heterozygote mice (Ht) and lipocalin 2 deficient mice (Lcn2 KO) were studied, as well as re-established microbiota after antibiotic perturbation, by collecting stool samples. Microbial community profiles were generated by the use of PCR and denaturing gradient gel electrophoresis (DGGE). The gels were analysed by the software program gel2K (Norland, 2002) and band intensity profiles were compared by statistical analysis. The study of mice gut microbiota revealed differences in the microbial profiles between Wt-, Ht- and Lcn 2 KO-mice. The result showed that both the factor of genotype and habitation were significant factors for the observed differences. For the single-housed mice (mice of same genotype), a significant difference of gut microbiota was found between Wt/Ht-mice and Lcn 2 KO-mice, indicating that the genotype was the main factor for the observed differences. Lcn 2 thus seems to influence the natural colonization of the mice gut, as well as the re-establishment of the microbiota after a perturbation with antibiotics treatment.For the co-housed mice (mice of mixed genotypes) both the effect of genotype and maternity seemed to influence the composition of the microbiota, although the factor of maternity was not taken into account in the analysis. The experimental set-up was designed with the intention of comparing littermates in order to minimize other effects than the knockout of Lcn2. Unfortunately this design meant that the effect of genotype and maternity could not be differentiated.

Flere studier har vist at saltinntaket til mennesker er for høyt, noe som kan føre til økt risiko for blant annet høyt blodtrykk og hjerte- og karsykdommer. Den største delen av saltinntaket kommer fra mat som er bearbeidet. En reduksjon i saltinnholdet i bearbeidede næringsmidler vil ikke bare påvirke smak, men også funksjonelle egenskaper som vannbindingsevne, koketap, geldanning, proteinløselighet og tekstur. Disse egenskapene påvirker også de sensoriske egenskapene. Det er derfor nødvendig med kunnskap om tilsetninger som kan brukes ved lavere saltkonsentrasjoner for å opprettholde både funksjonelle og sensoriske egenskaper i produktet.Hensikten med denne oppgaven var å studere de fysiokjemiske egenskapene til et modellprodukt av fiskepudding tilsatt en lav saltkonsentrasjon (NaCl), natriumalginat (NA) (1,1%) og disse i kombinasjon. Det ble også målt reologi for fiskefarse tilsatt NA og for et gelet system tilsatt NA, CaCO3 og glukono-δ-lakton (GDL).Tilsats av NA (1,1 %), CaCO3 (0,2 %) og GDL (0,6 %) til fiskefarse ga signifikant økt vannbinding og redusert koketap i fiskepudding sammenliknet med fiskepudding av farse som kun var tilsatt NaCl (0,4 %). Det var også tendenser til at fiskepudding tilsatt NA dannet en sterkere gel for varmebehandlet fiskepudding sammenliknet med fiskepudding tilsatt NaCl. Dette var tilfellet både for fiskepudding laget av ferskt og av fryst råstoff av hyse. Proteinløseligheten til fiskefarsen tydet på at tilsats av NA bidro i større grad til dannelse av gel enn geling av myofibrillproteiner.Ved å tilsette NA (1 %), CaCO3 og GDL til fiskemasse (fisk og vann) ble det dannet en gel uten varmebehandling av fiskefarsen, reologiske målinger viste at gelen økte i styrke i løpet av 20 timer.Dette tyder på at tilsats av NA, CaCO3 og GDL til fiskefarse bedrer de fysiokjemiske egenskapene til varmebehandlet fiskefarse både av fryst og ferskt råstoff, samt danner en gel i fiskefarse ved lave temperaturer.

The skin is the largest organ of the human body and it constitutes a great protective barrier against entry of harmful microbial species and foreign materials into the body. The barrier function is a result of the highly hydrophobic nature and compact structure of the outermost skin layer, which makes transdermal delivery of drugs difficult. The aim of this study was to investigate diffusion of hydrophilic fish gelatin peptides and alginate oligomers (G-blocks) into human skin, and to evaluate the effect of skin pretreatments, vehicles and the different characteristics of the test samples on transdermal diffusion.Fish gelatin was degraded by acid hydrolysis to produce peptides of varying molecular size, and the molecular weight distribution and molecular weight averages of the peptides were determined. Further, peptides were conjugated to fluorescent dyes, and together with fluorescently labeled G-block oligomers, they were utilized as traceable model drugs in the transdermal diffusion experiments. Full-scale skins, from healthy human adults after abdominal plastic surgery, were used and the transdermal diffusion experiments were performed in Franz-type diffusion cells. The surface of the skin tissues mounted in the diffusion cells was either untreated or treated with micro-needles or lasers, to disrupt the skin barrier. The model drugs were applied on the epidermal side of the skins in both a 60% dimethyl sulfoxide (DMSO) and a 10% polyethylene glycol 200 (PEG200) vehicle, and the vehicles were also separately applied on skins as control samples. After the transdermal diffusion experiments, imaging of the skin tissues were performed by confocal laser scanning microscopy.An incubation time of 22 hours was determined for the transdermal diffusion experiments and pretreatments were necessary for the model drugs to successfully diffuse into the skin. Pretreatments with micro-needles and laser resulted in enhanced diffusion of the test molecules into the skin tissues compared to diffusion into untreated skin. Laser treatment was found to have the most profound enhancing effect on transdermal diffusion, and enabled efficient diffusion both into and through the skin. Of the four model drugs chosen for use in the experiments, the smallest fish gelatin peptide sample, with an estimated average molecular weight of 3000 g/mol, applied on skin tissues in a 10% PEG200 vehicle, showed the most efficient diffusion into and through human skin.

Extraction and Analysis of Marine Lipids with Emphasis on Phospholipids- Evaluation and Improvement of Methods

Prosessert mat utgjør en av de største kildene til natrium i vestlig kosthold. Et forhøyet inntak av natrium er forbundet med høyt blodtrykk, noe som øker risikoen for hjerte- og karsykdommer. Denne kunnskapen har økt interessen for kjøtt- og fiskeprodukter med lavere NaCl-innhold - såkalte lavsaltprodukter. Lavere natriuminnhold oppnås ved å redusere mengden NaCl og/eller tilsette salterstattere.Formålet med denne studien var å undersøke hvordan ulike konsentrasjoner av NaCl, KCl og MgCl2 påvirker proteinløselighet i fisk. Forskjeller mellom ferskt og fryst råstoff for filet og farse av sei, hyse, torsk og kvitlaks ble undersøkt for å finne ut om KCl og MgCl2 kan brukes som salterstattere i farseprodukter av disse fiskeslagene. Målinger av proteinløselighet ble satt i sammenheng med målinger av pH og vannbindingsevne (VBE) i de ulike råstoffene. Påvirkning av Na-alginat, Na-alginat+NaCl og NaCl på proteinløselighet i farser av fersk og av fryst hyse ble undersøkt, og koblet opp mot de funksjonelle egenskapene til et varmebehandlet modellprodukt. Varmepåvirkning på VBE i farser med og uten tilsatt NaCl ble undersøkt.Proteinløselighet var høyest i fersk filet og sank som en følge av frysing og kverning. For fersk filet ble det ikke funnet forskjeller mellom sei, hyse og torsk i mengde ekstrahert saltløselig protein (SLP). For fryst filet ble det generelt sett ekstrahert en større mengde SLP fra hyse enn fra sei og torsk. For fersk farse ble det ekstrahert mest SLP fra torsk, men for farse av fryst råstoff ble det ekstrahert mest SLP fra kvitlaks. Når mengde ekstrahert SLP og SDS-PAGE-profil ble tatt i betraktning, ble 0,6 M NaCl vurdert som den beste proteinekstraktanten. Tett etter 0,6 M NaCl fulgte 0,3 M MgCl2 og 0,3 M NaCl. 0,3 M KCl, 0,6 M MgCl2 og 0,6 M KCl ble vurdert som de dårligste proteinekstraktantene. Dette skyldtes i hovedsak at myosinets tunge kjede generelt ikke så ut til å bli ekstrahert med de to sistnevnte, noe som kan ha betydning for geldannings- og vannbindingsevnen til produktet. Ekstraksjon av myosinets tunge kjede med 0,3 M KCl så ut til å være råstoffavhengig. På grunnlag av dette ble 0,3 M MgCl2 vurdert som den beste salterstatteren. Tilsetningsstoffer til farser av hyse, slik som Na-alginat, Na-alginat+NaCl og NaCl hadde alle en positiv effekt på proteinløselighet, og så ut til å kunne kompensere for bruk av en dårlig proteinekstraktant eller en proteinekstraktant med lav konsentrasjon. Varmebehandling av farser/puddinger med og uten tilsetninger viste at VBE nådde et minimum ved rundt 50 grader celcius, og at den økte ved høyere temperaturer, trolig som en følge av gelning av myosin. VBE var lavest i råstoff uten tilsetning, og økte ved tilsetning av NaCl, Na-alginat + NaCl og Na-alginat. Av tilsetningsstoffene hadde Na-alginat (med eller uten NaCl) best effekt, både på VBE, drypptap og tekstur. pH varierte i sei, hyse, torsk og kvitlaks, og økte etter frysing. For ferskt råstoff viste VBE en svak positiv korrelasjon med pH (10% signifikansnivå), men for fryst råstoff var det ingen klar sammenheng. For torsk og hyse økte VBE litt som en følge av frysing (5% signifikansnivå), mens den sank for sei.

Alginate is a naturally ocurring polyanion of (1→4)linked β-d-mannuronic acid (M)and its C-5 epimer α-l guluronic acid (G). The polyanion, and particularly longstretches of guluronic acids, chelates and form hydrogels in the presence of divalentcations such as Ca2+ . Chelation occur at physiological conditions and the formed hy-drogels are biocompatible and stable. These properties nominates alginate hydrogelsas promising biomaterials in tissue engineering applications. Encapsulation of cells inalginate beads is easily prepared by mixing cells with high molecular weight alginate,and dripping the solution into a CaCl2 solution. When alginate comes into contactwith Ca2+ ions, alginate beads are immediately formed and the cells are captured ina three dimensional alginate matrix. Once inside the alginate capsule, the cells canbe transplanted into a host deficient in the particular cells. The alginate protectsthe cells against the immune system of the host, opening for allograf transplantationwithout immunosuppressiva. The pores in the alginate network are big enough toenable diffusion of waste and nutrition through the membrane, which is importantfor cell survival.Alginate is in itself not cell adhesive. However, alginate can be tailored into a celladhesive biomaterial by attachement of cell adhesive peptides, such as the RGDmotif found in extracellular matrix molecules such as fibronectin. Coupling of celladhesive peptides increase cell survival in three dimensional alginate matrices. Inthis study, RGD-alginate is tailored with a chemoenzymatic approach that ensuresRGD-coupling to non-gelling residues. This procedure starts with non-gelling man-nuronan that is chemically modified by attachement of the cell adhesive peptideGRGDYP by carbodiimide chemistry. Gelling residues are introduced to peptidecoupled mannuronan by a two step epimerisation catalyzed by the epimerases AlgE4and AlgE6.In this study, the carbodiimide chemsitry used for coupling GRGDYP to mannuro-nan is optimalised to create alginate with more than 0.2% bound peptide. Themodel molecules fluoresceinamine, 4-aminophenol and L-tyrosine-methyl ester areused for optimalisation, and the latter model molecule was found to give the bestrepresentation of peptide coupling to mannuronan. The carbodiimide mediated cou-pling to mannuronan is investigated by varying the pH, temperature and reactantconcentrations. The degrees of coupling for each intervention is assessed by 1 H NMRand UV/vis spectroscopy. The presence of covalently bound by-products, namedN-acylurea adducts, to mannuronan is assessed by 1 H NMR spectroscopy and acontrolled reduction of these unwanted compounds is attempted. The results from the optimalisation indicates that coupling of Me-O-Tyr and GRGDYP to mannuro-nan is concentration-dependent, as an increase in coupling was observed when theGRGDYP and Me-O-Tyr concentrations was increased. The highest peptide incor-poration described in this study was 3.4% GRGDYP coupled to mannuronan, whichis higher compared to similar studies.The optimalised carbodiimide chemistry is applied to a large scale batch of RGD-coupled alginate that is to be used for cell encapsulation of olfactory ensheating cellsfrom neonatal rat brain.High molecular weight alginate was coupled with 0.45% GRGDYP and filtratedwith active coal before cell encapsulation. The coal filtration removed a substantialamount of the unwanted N-acylurea adducts but also removed peptides, resultingin a GRGDYP coupling of 0.1% calculated from UV/vis spectroscopy, and 0.4%calculated from 1 H NMR spectroscopy. This indicates that peptides are associatedwith N-acylurea adducts and that active coal filtration is necessary to remove them.Encapsulation of olfactory ensheating cells to RGD-coupled alginate gave no mor-phology changes or enhanced cell viability compared to non-peptide coupled alginate.It is believed that the low enzymatic action of the AlgE6 epimerase, a low concen-tration of peptides or a combination of both, have influenced the cell viability andlack of morphology changes. Enhanced peptide incorporation can be achieved byincreasing the reactant concentrations of the peptides, but this would lead to a moreexpensive procedure. Increased efficacy, meaning a higher peptide coupling withlower adduct formation, at lower peptide concentrations was not achieved. However,the use of sodium borohydride in combination with periodate oxidised alginates forpeptide coupling should be assessed as a novel approach for increased peptide yieldsat lower peptide concentrations.