Overvåking i referanseelver Oppsummering av data for perioden 2017-2023

Prosjektleder: Tor Erik EriksenOvervåkingsprogrammet «Overvåking i referanseelver» undersøker miljøtilstanden i norske elver og bekker med antatt liten grad av menneskelig påvirkning. Denne rapporten sammenstiller resultater og vurderer økologisk tilstand per år og per vannforekomst for perioden 2017-2023, med fokus på vannkjemiske parametere for eutrofiering og forsuring, samt de biologiske kvalitetselementene bunndyr (indeksene ASPT og RAMI), begroingsalger (indeksene PIT og AIP) og fisk (fiskeindeksen). I tillegg omfatter rapporten analyser av miljøgifter i fisk. Resultatene diskuteres med hensyn til presisjon, usikkerhet og variasjon i indeksverdier og tilstand. Resultatene viser at noen av de antatt upåvirkede vassdragene faktisk er påvirket av menneskelig aktivitet. Dette er vist gjennom analyser av fysisk-kjemiske parametere (som næringsstoffer og forsuringsparametere), kjemisk tilstand (miljøgifter) og biologiske indekser for begroingsalger, bunndyr og fisk. Datasammenstillingen viser også usikkerhet knyttet til dagens metodikk for tilstandsklassifisering og fremhever behovet for utbedringer for noen av vurderingssystemene for å øke presisjonen i vurderingene. Spesielt gjelder dette de biologiske indeksene AIP (forsuring), ASPT (eutrofiering/organisk forurensning) og fiskeindeksen, der forholdsvis mange vannforekomster ikke oppnådde den forventede tilstandsklassen svært god. Vi foreslår videre arbeid med disse indeksene for å eventuelt justere forventningsverdiene, og dermed forbedre vurderingssystemene for tilstandsklassifisering av norske vassdrag.MiljødirektoratetpublishedVersio

Overcoming drug resistance with alginate oligosaccharides able to potentiate the action of selected antibiotics

The uncontrolled, often inappropriate use of antibiotics has resulted in the increasing prevalence of antibiotic-resistant pathogens, with major cost implications for both US and European healthcare systems. We describe the utilization of a low molecular weight oligosaccharide nanomedicine (OligoG) based on the biopolymer alginate, which is able to perturb multi-drug resistant (MDR) bacteria by modulating biofilm formation/persistence and reducing resistance to antibiotic treatment; evident using conventional and robotic MIC screening and microscopic analyses of biofilm structure. OligoG increased the efficacy of conventional antibiotics (up to 512-fold) against important MDR pathogens including Pseudomonas, Acinetobacter and Burkholderia spp., appearing to be effective with several classes of antibiotic (i.e. macrolides, β-lactams, tetracyclines). Using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) increasing concentrations of alginate oligomer (2, 6 and 10%) were shown have a direct effect on the quality of the biofilms produced and on the health of the cells within that biofilm. Biofilm growth was visibly weakened in the presence of 10% OligoG as seen by decreased biomass and increased intercellular spaces, with the bacterial cells themselves becoming distorted and uneven due to apparently damaged cell membranes. This study demonstrates the feasibility of reducing the tolerance of wound biofilms to antibiotics with the use of specific alginate preparations

A New Class of Safe Oligosaccharide Polymer Therapy To Modify the Mucus Barrier of Chronic Respiratory Disease

The host- and bacteria-derived extracellular polysaccharide coating of the lung is a considerable challenge in chronic respiratory disease and is a powerful barrier to effective drug delivery. A low molecular weight 12–15-mer alginate oligosaccharide (OligoG CF-5/20), derived from plant biopolymers, was shown to modulate the polyanionic components of this coating. Molecular modeling and Fourier transform infrared spectroscopy demonstrated binding between OligoG CF-5/20 and respiratory mucins. Ex vivo studies showed binding induced alterations in mucin surface charge and porosity of the three-dimensional mucin networks in cystic fibrosis (CF) sputum. Studies in Humans showed that OligoG CF-5/20 is safe for inhalation in CF patients with effective lung deposition and modifies the viscoelasticity of CF-sputum. OligoG CF-5/20 is the first inhaled polymer therapy, represents a novel mechanism of action and therapeutic approach for the treatment of chronic respiratory disease, and is currently in Phase IIb clinical trials for the treatment of CF

The effect of alginate oligosaccharides on the mechanical properties of Gram-negative biofilms

The influence of a novel, safe antibiofilm therapy on the mechanical properties of Pseudomonas aeruginosa and Acinetobacter baumannii biofilms in vitro was characterized. A multiscale approach employing atomic force microscopy (AFM) and rheometry was used to quantify the mechanical disruption of the biofilms by a therapeutic polymer based on a low-molecular weight alginate oligosaccharide (OligoG). AFM demonstrated structural alterations in the biofilms exposed to OligoG, with significantly lower Young’s moduli than the untreated biofilms, (149 MPa vs 242 MPa; p < 0.05), a decreased resistance to hydrodynamic shear and an increased surface irregularity (Ra) in the untreated controls (35.2 nm ± 7.6 vs 12.1 nm ± 5.4; p < 0.05). Rheology demonstrated that increasing clinically relevant concentrations of OligoG (<10%) were associated with an increasing phase angle (δ) over a wide range of frequencies (0.1–10 Hz). These results highlight the utility of these techniques for the study of three-dimensional biofilms and for quantifying novel disruption therapies in vitro

Overcoming Drug Resistance with Alginate Oligosaccharides Able To Potentiate the Action of Selected Antibiotics

The uncontrolled, often inappropriate use of antibiotics has resulted in the increasing prevalence of antibiotic-resistant pathogens, with major cost implications for both US and European healthcare systems. We describe the utilization of a low molecular weight oligosaccharide nanomedicine (OligoG) based on the biopolymer alginate, which is able to perturb multi-drug resistant (MDR) bacteria by modulating biofilm formation/persistence and reducing resistance to antibiotic treatment; evident using conventional and robotic MIC screening and microscopic analyses of biofilm structure. OligoG increased the efficacy of conventional antibiotics (up to 512-fold) against important MDR pathogens including Pseudomonas, Acinetobacter and Burkholderia spp., appearing to be effective with several classes of antibiotic (i.e. macrolides, β-lactams, tetracyclines). Using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) increasing concentrations of alginate oligomer (2, 6 and 10%) were shown have a direct effect on the quality of the biofilms produced and on the health of the cells within that biofilm. Biofilm growth was visibly weakened in the presence of 10% OligoG as seen by decreased biomass and increased intercellular spaces, with the bacterial cells themselves becoming distorted and uneven due to apparently damaged cell membranes. This study demonstrates the feasibility of reducing the tolerance of wound biofilms to antibiotics with the use of specific alginate preparations