English
norskBlar i forfatter "Isaksson, Johan"
Viser treff 21-32 av 32
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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</i>-Cys<sup>6</sup>, Cys<sup>2</sup>-Cys<sup>5</sup>, and ... -
Kinase chemodiversity from the Arctic: the breitfussins
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-24)In this work, we demonstrate that the indole-oxazole-pyrrole framework of the breitfussin family of natural products is a promising scaffold for kinase inhibition. Six new halogenated natural products, breitfussin C–H (3 – 8) were isolated and characterized from the Arctic, marine hydrozoan Thuiaria breitfussi. The structures of two of the new natural products were also confirmed by total synthesis. ... -
Lulworthinone, a New Dimeric Naphthopyrone From a Marine Fungus in the Family Lulworthiaceae With Antibacterial Activity Against Clinical Methicillin-Resistant Staphylococcus aureus Isolates
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-01)The emergence of drug-resistant bacteria is increasing rapidly in all parts of the world, and the need for new antibiotics is urgent. In our continuous search for new antimicrobial molecules from under-investigated Arctic marine microorganisms, a marine fungus belonging to the family Lulworthiaceae (Lulworthiales, Sordariomycetes, and Ascomycota) was studied. The fungus was isolated from driftwood, ... -
Novel antimicrobial peptides EeCentrocins 1, 2 and EeStrongylocin 2 from the Edible sea urchin Echinus esculentus have 6-br-trp post-translational modifications
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-23)The global problem of microbial resistance to antibiotics has resulted in an urgent need to develop new antimicrobial agents. Natural antimicrobial peptides are considered promising candidates for drug development. Echinoderms, which rely on innate immunity factors in the defence against harmful microorganisms, are sources of novel antimicrobial peptides. This study aimed to isolate and characterise ... -
A Novel Brominated Alkaloid Securidine A, Isolated from the Marine Bryozoan Securiflustra securifrons
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-23)A novel brominated alkaloid, Securidine A, was isolated from the cold water marine bryozoan Securiflustra securifrons. Securidine A was isolated using semi-preparative HPLC, and the structure was elucidated by spectroscopic methods. The isolated Securidine A was tested for cytotoxic, antibacterial, and anti-diabetic activities as well as for its potential for inhibition of biofilm formation. No ... -
A Novel brominated Alkaloid Securidine A, Isolated from the Marine Bryozoan Securiflustra securifrons
(Conference object; Konferansebidrag, 2017)A novel brominated alkaloid, Securidine A, was isolated from the cold water marine bryozoan Securiflustra securifrons. Securidine A was isolated using semi-preparative HPLC, and the structure was elucidated by spectroscopic methods. The isolated Securidine A was tested for cytotoxic, antibacterial, and anti-diabetic activities as well as for its potential for inhibition of biofilm formation. No ... -
Ponasterone A and F, Ecdysteroids from the Arctic Bryozoan Alcyonidium gelatinosum
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-19)A new ecdysteroid, ponasterone F (1) and the previously reported compound ponasterone A (2) were isolated from specimens of the Arctic marine bryozoan Alcyonidium gelatinosum collected at Hopenbanken, off the coast of Edgeøya, Svalbard. The structure of 1 was elucidated, and the structure of 2 confirmed by spectroscopic methods including 1D and 2D NMR and analysis of HR-MS data. The compounds were ... -
Risky sexual behaviour among Russian adolescents: association with internalizing and externalizing symptoms
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-09)<i>Background</i> - Risky sexual behaviour (RSB) is regarded as a major health problem during adolescence. Russia has one of the highest rates of teenage pregnancy, abortion and newly diagnosed HIV infections in the world, but research on RSB in Russian youth has been limited. To address this deficit, this study examined the role of several factors, including internalizing and externalizing symptoms, ... -
Synthetic cationic antimicrobial peptides bind with their hydrophobic parts to drug site II of human serum albumin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Total Synthesis of Phorbazole B
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-21)Phorbazoles are polychlorinated heterocyclic secondary metabolites isolated from a marine sponge and several of these natural products have shown inhibitory activity against cancer cells. In this work, a synthesis of the trichlorinated phorbazole B using late stage electrophilic chlorination was developed. The synthesis relied on the use of an oxazole precursor, which was protected with an iodine ... -
Two Novel Lyso-Ornithine Lipids Isolated from an Arctic Marine Lacinutrix sp. Bacterium
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-31)The Lacinutrix genus was discovered in 2005 and includes 12 Gram-negative bacterial species. To the best of our knowledge, the secondary metabolite production potential of this genus has not been explored before, and examination of Lacinutrix species may reveal novel chemistry. As part of a screening project of Arctic marine bacteria, the Lacinutrix sp. strain M09B143 was cultivated, extracted, ... -
Unequivocal structure confirmation of a breitfussin analog by anisotropic NMR measurements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-21)Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy. For the breitfussins in particular, the constitution of the five-membered oxazole central ring cannot be unequivocally established via conventional NMR methods when the 4′-position is halogenated. The level of difficulty is exacerbated ...
