Search results for "biosynteesi"
showing 6 items of 6 documents
The structure and biosynthesis of heinamides A1-A3 and B1-B5, antifungal members of the laxaphycin lipopeptide family.
2021
Laxaphycins are a family of cyclic lipopeptides with synergistic antifungal and antiproliferative activities. They are produced by multiple cyanobacterial genera and comprise two sets of structurally unrelated 11- and 12-residue macrocyclic lipopeptides. Here, we report the discovery of new antifungal laxaphycins from Nostoc sp. UHCC 0702, which we name heinamides, through antimicrobial bioactivity screening. We characterized the chemical structures of eight heinamide structural variants A1-A3 and B1-B5. These variants contain the rare non-proteinogenic amino acids 3-hydroxy-4-methylproline, 4-hydroxyproline, 3-hydroxy-d-leucine, dehydrobutyrine, 5-hydroxyl beta-amino octanoic acid, and O-c…
Variation in ω-3 and ω-6 Polyunsaturated Fatty Acids Produced by Different Phytoplankton Taxa at Early and Late Growth Phase
2020
Phytoplankton synthesizes essential ω-3 and ω-6 polyunsaturated fatty acids (PUFA) for consumers in the aquatic food webs. Only certain phytoplankton taxa can synthesize eicosapentaenoic (EPA; 20:5ω3) and docosahexaenoic acid (DHA; 22:6ω3), whereas all phytoplankton taxa can synthesize shorter-chain ω-3 and ω-6 PUFA. Here, we experimentally studied how the proportion, concentration (per DW and cell-specific), and production (µg FA L-1 day-1) of ω-3 and ω-6 PUFA varied among six different phytoplankton main groups (16 freshwater strains) and between exponential and stationary growth phase. EPA and DHA concentrations, as dry weight, were similar among cryptophytes and diatoms. However, Crypto…
The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium
2019
Microcystins are a family of chemically diverse hepatotoxins produced by distantly related cyanobacteria and are potent inhibitors of eukaryotic protein phosphatases 1 and 2A. Here we provide evidence for the biosynthesis of rare variants of microcystin that contain a selection of homo-amino acids by the benthic cyanobacterium Phormidium sp. LP904c. This strain produces at least 16 microcystin chemical variants many of which contain homophenylalanine or homotyrosine. We retrieved the complete 54.2 kb microcystin (mcy) gene cluster from a draft genome assembly. Analysis of the substrate specificity of McyB1 and McyC adenylation domain binding pockets revealed divergent substrate specificity …
Alternative Biosynthetic Starter Units Enhance the Structural Diversity of Cyanobacterial Lipopeptides
2019
Puwainaphycins (PUWs) and minutissamides (MINs) are structurally analogous cyclic lipopeptides possessing cytotoxic activity. Both types of compound exhibit high structural variability, particularly in the fatty acid (FA) moiety. Although a biosynthetic gene cluster responsible for synthesis of several PUW variants has been proposed in a cyanobacterial strain, the genetic background for MINs remains unexplored. Herein, we report PUW/MIN biosynthetic gene clusters and structural variants from six cyanobacterial strains. Comparison of biosynthetic gene clusters indicates a common origin of the PUW/MIN hybrid nonribosomal peptide synthetase and polyketide synthase. Surprisingly, the biosynthet…
Production of High Amounts of Hepatotoxin Nodularin and New Protease Inhibitors Pseudospumigins by the Brazilian Benthic Nostoc sp. CENA543
2017
Nostoc is a cyanobacterial genus, common in soils and a prolific producer of natural products. This research project aimed to explore and characterize Brazilian cyanobacteria for new bioactive compounds. Here we report the production of hepatotoxins and new protease inhibitors from benthic Nostoc sp. CENA543 isolated from a small, shallow, saline-alkaline lake in the Nhecolandia, Pantanal wetland area in Brazil. Nostoc sp. CENA543 produces exceptionally high amounts of nodularin-R. This is the first free-living Nostoc that produces nodularin at comparable levels as the toxic, bloom-forming, Nodularia spumigena. We also characterized pseudospumigins A-F, which are a novel family of linear te…
De novo Synthesis of Chemical Defenses in an Aposematic Moth
2018
Many animals protect themselves from predation with chemicals, both self-made or sequestered from their diet. The potential drivers of the diversity of these chemicals have been long studied, but our knowledge of these chemicals and their acquisition mode is heavily based on specialist herbivores that sequester their defenses. The wood tiger moth (Arctia plantaginis, Linnaeus, 1758) is a well-studied aposematic species, but the nature of its chemical defenses has not been fully described . Here, we report the presence of two methoxypyrazines, 2-sec-butyl-3-methoxypyrazine and 2-isobutyl-3-methoxypyrazine, in the moths’ defensive secretions. By raising larvae on an artificial diet, we confir…