English
norskBlar i forfatter "Isaksson, Johan"
Viser treff 1-20 av 32
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Amphipathic Barbiturates as Mimics of Antimicrobial Peptides and the Marine Natural Products Eusynstyelamides with Activity against Multi-resistant Clinical Isolates
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-27)We report a series of synthetic cationic amphipathic barbiturates inspired by the pharmacophore model of small antimicrobial peptides (AMPs) and the marine antimicrobials eusynstyelamides. These N,N′-dialkylated-5,5-disubstituted barbiturates consist of an achiral barbiturate scaffold with two cationic groups and two lipophilic side chains. Minimum inhibitory concentrations of 2–8 μg/mL were achieved ... -
Anti-Bacterial Effect and Cytotoxicity Assessment of Lipid 430 Isolated from Algibacter sp.
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-05)Two bacterial isolates from the Barents Sea, both belonging to the genus <i>Algibacter</i>, were found to yield extracts with anti-bacterial bioactivity. Mass spectrometry guided dereplication and purification of the active extracts lead to the isolation of the same active principle in both extracts. The structure of the bioactive compound was identified via mass spectrometry and nuclear resonance ... -
Anti-proliferative activity of a novel tricyclic triterpenoid acid from Commiphora africana resin against four human cancer cell lines
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-17)Myrrh, a resin derived from the damaged bark of Commiphora genus, has traditionally been used for treatment of various human diseases, such as amenorrhea, ache, tumors, fever, and stomach pains. In spite of this widespread use of the myrrh in Ethiopia, the pharmacological activity and chemical composition have not been studied in detail. A new tricyclic triterpene acid (3S,4S,14S,7E,17E,21Z)-3, ... -
The Arabidopsis (ASHH2) CW domain binds monomethylated K4 of the histone H3 tail through conformational selection
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-21)Chromatin post‐translational modifications are thought to be important for epigenetic effects on gene expression. Methylation of histone N‐terminal tail lysine residues constitutes one of many such modifications, executed by families of histone lysine methyltransferase (HKMTase). One such protein is ASHH2 from the flowering plant <i>Arabidopsis thaliana</i>, equipped with the interaction domain, CW, ... -
Attention-deficit/hyperactivity disorder symptoms, perceived stress, and suicidal ideation during the COVID-19 pandemic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)Objective: Attention–deficit/hyperactivity disorder (ADHD) symptoms have been linked to suicidal behavior. However, little is known about the mechanisms involved in this association. This study examined ADHD symptoms and suicidal ideation during the COVID-19 pandemic and the role of self–perceived stress in this association.<p> <p>Method: Data were analyzed from an online sample of 1,452 Japanese ... -
Beta-glucan-loaded nanofiber dressing improves wound healing in diabetic mice
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-01)The increased prevalence of chronic wounds requires novel treatment options. The aim of this study was to develop a beta-glucan (βG)-loaded nanofiber wound dressing. Nanofibers were prepared using the needle-free Nanospider™ technology, an electrospinning method which enables the production of nanofibers at an industrial scale. The βG was selected as active ingredient based on its confirmed wound ... -
Bioactivity of Serratiochelin A, a Siderophore Isolated from a Co-Culture of Serratia sp. and Shewanella sp.
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-14)Siderophores are compounds with high affinity for ferric iron. Bacteria produce these compounds to acquire iron in iron-limiting conditions. Iron is one of the most abundant metals on earth, and its presence is necessary for many vital life processes. Bacteria from the genus <i>Serratia</i> contribute to the iron respiration in their environments, and previously several siderophores have been isolated ... -
Cellular Antioxidant Effect of Four Bromophenols from the Red Algae, Vertebrata lanosa
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)Three known bromophenols, 2,3-dibromo-4,5-dihydroxybenzylaldehyde (1), 2,2′,3-tribromo-3′,4,4′,5-tetrahydroxy 6′-hydroxymethyldiphenylmethane (2) and bis(2, 3-dibromo-4,5-dihydroxylbenzyl) ether (3), and one new one, 5,5″-oxybis(methylene)bis (3-bromo-4-(2′,3′-dibromo-4′,5′-dihydroxylbenzyl)benzene-1,2-diol) (4), were isolated from an extract of the red alga, Vertebrata lanosa. The antioxidant ... -
Characterization of Rhamnolipids Produced by an Arctic Marine Bacterium from the Pseudomonas fluorescence Group
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-14)The marine environment is a rich source of biodiversity, including microorganisms that have proven to be prolific producers of bioactive secondary metabolites. Arctic seas are less explored than warmer, more accessible areas, providing a promising starting point to search for novel bioactive compounds. In the present work, an Arctic marine Pseudomonas sp. belonging to the Pseudomonas (P.) fluorescence ... -
Chlovalicin B, a Chlorinated Sesquiterpene Isolated from the Marine Mushroom Digitatispora marina
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-13)As part of our search for bioactive metabolites from understudied marine microorganisms, the new chlorinated metabolite chlovalicin B (1) was isolated from liquid cultures of the marine basidiomycete Digitatispora marina, which was collected and isolated from driftwood found at Vannøya, Norway. The structure of the novel compound was elucidated by spectroscopic methods including 1D and 2D NMR and ... -
Community Violence Exposure and Eating Disorder Symptoms among Belgian, Russian and US Adolescents: Cross-Country and Gender Perspectives
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-22)Community violence exposure (CVE) is one of the most common adverse childhood experiences worldwide. Despite this, its potential effect on disordered eating in adolescents from different cultures is underexplored. In the present crosssectional study, self-reported data were collected from 9751 students (Mean age=14.27) from Belgium, Russia and the US on CVE (witnessing violence and violence ... -
Community Violence Exposure and School Functioning in Youth: Cross-Country and Gender Perspectives
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-27)<i>Background</i>: Many children and adolescents experience violent events which can be associated with negative consequences for their development, mental health, school, and social functioning. However, findings between settings and on the role of gender have been inconsistent. This study aimed to investigate cross-country and gender differences in the relationship between community violence ... -
CSSF-CLIP-HSQMBC: measurement of heteronuclear coupling constants in severely crowded spectral regions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-05)A new pulse program development, a chemical shift selective filtration clean in-phase HSQMBC (CSSF-CLIP-HSQMBC), is presented for the user-friendly measurement of long-range heteronuclear coupling constants in severely crowded spectral regions. The introduction of the chemical shift selective filter makes the experiment extremely efficient at resolving overlapped multiplets and produces a clean ... -
Demetalation of copper undecaarylcorroles: Molecular structures of a free-base undecaarylisocorrole and a gold undecaarylcorrole
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-27)Copper undecaarylcorroles were found to undergo acid-induced demetalation with unusual ease under both reductive and nonreductive conditions. The resulting free-base undecaarylcorroles were found to be rather reactive, readily photooxygenating to yield 5/10-hydroxyisocorroles and open-chain tetrapyrroles. The use of nonreductive conditions led to 50-75% yields of undecaarylisocorroles, a new class ... -
Dendrobeaniamine A, a new alkaloid from the Arctic marine bryozoan Dendrobeania murrayana
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-20)The new guanidine alkaloid Dendrobeaniamine A (1) was isolated from the organic extract of the Arctic marine bryozoan <i>Dendrobeania murrayana</i>. The chemical structure of 1 was elucidated by spectroscopic experiments, including 1D and 2D NMR and HRESIMS analysis. Compound 1 is a lipoamino acid, consisting of a C<sub>12</sub> fatty acid anchored to the amino acid arginine. The bioactivity of 1 ... -
Depressive symptoms and anger and aggression in Russian adolescents
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-16)Research among adolescents exploring the association between depressive symptoms and aggression has produced inconsistent findings. This study investigated the prevalence of clinically significant (current major depressive episode) and subthreshold depressive symptoms in a general population sample of adolescents from Northern Russia and explored their association with aggression and anger, while ... -
Development of a biomimetic phospholipid vesicle-based permeation assay for the estimation of intestinal drug permeability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Experimental and four-component relativistic DFT studies of tungsten carbonyl complexes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-24)We present a theoretical and experimental study of the structure and nuclear magnetic resonance (NMR) parameters of the pentacarbonyltungsten complexes of η<sup>1</sup>-2-(trimethylstannyl)-4,5-dimethylphosphinine, η<sup>2</sup>-norbornene, and imidazolidine-2-thione. The three complexes have a pseudo-octahedral molecular structure with the six ligands bonded to the tungsten atom. The η<sup>1</sup ... -
A focused fragment library targeting the antibiotic resistance enzyme - Oxacillinase-48: Synthesis, structural evaluation and inhibitor design
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-10)β-Lactam antibiotics are of utmost importance when treating bacterial infections in the medical community. However, currently their utility is threatened by the emergence and spread of β-lactam resistance. The most prevalent resistance mechanism to β-lactam antibiotics is expression of β-lactamase enzymes. One way to overcome resistance caused by β-lactamases, is the development of β-lactamase ... -
Isolation and characterization of antimicrobial peptides with unusual disulfide connectivity from the colonial ascidian Synoicum turgens
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-12)This study reports the isolation of two novel cysteine-rich antibacterial peptides, turgencin A and turgencin B, along with their oxidized derivatives, from the Arctic marine colonial ascidian <i>Synoicum turgens</i>. The peptides are post-translationally modified, containing six cysteines with an unusual disulfide connectivity of Cys<sup>1</sup>-Cys<sup>6</sup>, Cys<sup>2</sup>-Cys<sup>5</sup>, and ...
