ABSTRACT
The linear lipopeptides okeaniamide A (1) and okeaniamide B (2) were isolated from an Okeania sp. marine cyanobacterium collected in Okinawa. The structures of these compounds were established by spectroscopic analyses, and the absolute configurations were elucidated based on a combination of chemical degradations, Marfey's analysis, and derivatization reactions. Okeaniamide A (1) and okeaniamide B (2) dose-dependently promoted the differentiation of mouse 3T3-L1 preadipocytes in the presence of insulin.
Subject(s)
Cyanobacteria , Marine Biology , Mice , Animals , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Cyanobacteria/chemistry , Lipopeptides/chemistryABSTRACT
Lyngbyapeptin B is a hybrid polyketide-nonribosomal peptide isolated from particular marine cyanobacteria. In this report, we carried out genome sequence analysis of a producer cyanobacterium Moorena bouillonii to understand the biosynthetic mechanisms that generate the unique structural features of lyngbyapeptin B, including the (E)-3-methoxy-2-butenoyl starter unit and the C-terminal thiazole moiety. We identified a putative lyngbyapeptin B biosynthetic (lynB) gene cluster comprising nine open reading frames that include two polyketide synthases (PKSs: LynB1 and LynB2), four nonribosomal peptide synthetases (NRPSs: LynB3, LynB4, LynB5, and LynB6), a putative nonheme diiron oxygenase (LynB7), a type II thioesterase (LynB8), and a hypothetical protein (LynB9). In vitro enzymatic analysis of LynB2 with methyltransferase (MT) and acyl carrier protein (ACP) domains revealed that the LynB2 MT domain (LynB2-MT) catalyzes O-methylation of the acetoacetyl-LynB2 ACP domain (LynB2-ACP) to yield (E)-3-methoxy-2-butenoyl-LynB2-ACP. In addition, in vitro enzymatic analysis of LynB7 revealed that LynB7 catalyzes the oxidative decarboxylation of (4R)-2-methyl-2-thiazoline-4-carboxylic acid to yield 2-methylthiazole in the presence of Fe2+ and molecular oxygen. This result indicates that LynB7 is responsible for the last post-NRPS modification to give the C-terminal thiazole moiety in lyngbyapeptin B biosynthesis. Overall, we identified and characterized a new marine cyanobacterial hybrid PKS-NRPS biosynthetic gene cluster for lyngbyapeptin B production, revealing two unique enzymatic logics.
Subject(s)
Cyanobacteria , Peptides , Polyketides , Cyanobacteria/chemistry , Cyanobacteria/genetics , Cyanobacteria/metabolism , Peptide Synthases/metabolism , Polyketide Synthases/metabolism , Polyketides/chemistry , Thiazoles/metabolismABSTRACT
Caldorazole (1) was isolated from the marine cyanobacterium Caldora sp. collected on Ishigaki Island, Okinawa, Japan. Its structure was determined to be a new polyketide that contained two thiazole rings and an O-methylenolpyruvamide moiety. Caldorazole (1) showed strong cytotoxicity toward tumor cells that had been seeded at a high density. Cell death induced by 1 in HeLa and A431 cells was also observed only in the presence of the glycolysis blocker 2-deoxy-d-glucose (2DG). Co-treatment with 1 and 2DG remarkably decreased ATP levels in these cells. Furthermore, 1 selectively inhibited complex I in the mitochondrial respiratory chain. Thus, 1 was demonstrated to exert cytotoxicity toward human tumor cells by blocking mitochondrial respiration.
Subject(s)
Glucose , Polyketides , Deoxyglucose/pharmacology , Glycolysis , Humans , Polyketides/pharmacology , Thiazoles/pharmacologyABSTRACT
Marine macroscopic colony-forming filamentous (MMCFF) cyanobacteria are considered as prolific producers of bioactive compounds. Thus, knowledge of the diversity of MMCFF cyanobacteria as related to bioactive compound production has become very important. However, basic taxonomic studies of MMCFF cyanobacteria are lacking. Many cyanobacterial taxa are still misidentified or undescribed. In this study, a total of 32 cyanobacterial colonies from nine coastal regions of Okinawa Prefecture were investigated for a diversity assessment. A polyphasic approach including morphological and molecular studies based on 16S rRNA gene sequences was performed to characterize Okinawan MMCFF cyanobacteria. Both morphological and molecular phylogenetic results showed that MMCFF cyanobacteria from Okinawan coasts are very diverse. We found morphotypes of Lyngbya-like, Phormidium-like, and Leptolyngbya-like groups among Okinawan cyanobacterial samples. Genetically, samples were distributed in various clades in the phylogenetic tree, including within Moorena, Okeania, Caldora, Neolyngbya, Dapis, as well as several unknown clades. In addition, cytotoxic activities of three samples from Kiyan coast were tested against HeLa cells. All three crude extracts of these samples showed strong cytotoxic activity with IC50 < 1 µg/ml.
Subject(s)
Cyanobacteria/chemistry , Cyanobacteria/classification , Complex Mixtures/toxicity , Cyanobacteria/genetics , HeLa Cells , Humans , Phylogeny , RNA, Ribosomal, 16S/geneticsABSTRACT
Irijimasides A-E (1-5), a series of new 14-membered macrolide glycosides, were isolated from a marine cyanobacterium collected in Okinawa. The gross structures of 1-5 were established by spectroscopic analysis, including 2D NMR, while absolute stereostructures were determined based on NOESY spectra, chemical derivatization, and ECD data. All five macrolides suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP) activity in mouse RAW264 macrophage cells, indicating that these compounds inhibit osteoclast formation.
Subject(s)
Cyanobacteria/chemistry , Glycosides/chemistry , Macrolides/chemistry , Osteoclasts/drug effects , Tartrate-Resistant Acid Phosphatase/metabolism , Animals , Mice , Molecular Structure , RANK Ligand/chemistry , RANK Ligand/metabolism , Tartrate-Resistant Acid Phosphatase/chemistryABSTRACT
An antimalarial lipopeptide, ikoamide, was isolated from an Okeania sp. marine cyanobacterium. Its gross structure was established by spectroscopic analyses, and the absolute configuration was clarified based on a combination of chiral-phase HPLC analyses, spectroscopic analyses, and derivatization reactions. Ikoamide showed strong antimalarial activity with an IC50 value of 0.14 µM without cytotoxicity against human cancer cell lines at 10 µM.
Subject(s)
Antimalarials/pharmacology , Cyanobacteria/chemistry , Lipopeptides/chemistry , Antimalarials/chemistry , Chromatography, High Pressure Liquid , Humans , Lipopeptides/isolation & purification , Molecular Structure , Structure-Activity RelationshipABSTRACT
Minnamide A is a lipopeptide with a unique repeating structure consisting of hydroxy and proposed ß-branched methyl groups. The absolute configuration of minnamide A was determined by a combination of chemical degradation, chiral HPLC analyses, and synthetic methods. Minnamide A showed growth-inhibitory activity toward HeLa cells with an IC50 value of 0.17 µM and rapidly induced cell death at a concentration of 2 µM. Minnamide A induced the copper-mediated accumulation of reactive oxygen species.
Subject(s)
Cyanobacteria/chemistry , Lipopeptides/pharmacology , Cell Death/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , HeLa Cells , Humans , Lipopeptides/chemistry , Lipopeptides/isolation & purification , Molecular Conformation , Reactive Oxygen Species/metabolism , Structure-Activity RelationshipABSTRACT
Two new jahanyne analogues, jahanene and jahanane, highly N-methylated lipopeptides, were isolated from a marine cyanobacterium Okeania sp., and their structures were determined by NMR and MS. In addition, we achieved total syntheses of the jahanyne family and assessed their activities. The resulting growth-inhibitory activity of jahanyne was nearly one-tenth of the previously reported activity. Furthermore, we found that the degree of unsaturation at the terminus of the fatty acid moiety affected the growth-inhibitory activity against human cancer cells.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/isolation & purification , Lipopeptides/chemical synthesis , Lipopeptides/isolation & purification , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Proliferation/drug effects , Chemistry Techniques, Synthetic , Cyanobacteria/chemistry , Fatty Acids/chemistry , HeLa Cells , Humans , Lipopeptides/chemistry , Lipopeptides/pharmacology , Structure-Activity RelationshipABSTRACT
Izenamides A, B, and C (1-3), new linear depsipeptides, were isolated from a taxonomically distinct marine cyanobacterium. Izenamides A and B contain a statine moiety [(3 S,4 S)-4-amino-3-hydroxy-6-methylheptanoic acid] and inhibited the activity of cathepsin D, an aspartic peptidase. Meanwhile, izenamides did not show growth-inhibitory activity against HeLa, HL60, or MCF-7 cells at up to 10 µM.
Subject(s)
Cyanobacteria/chemistry , Depsipeptides/isolation & purification , Cathepsin D/antagonists & inhibitors , Cyanobacteria/classification , Cyanobacteria/isolation & purification , Depsipeptides/chemistry , Depsipeptides/pharmacology , Growth Inhibitors/chemistry , Growth Inhibitors/isolation & purification , Growth Inhibitors/pharmacology , HL-60 Cells , HeLa Cells , Humans , MCF-7 Cells , Molecular StructureABSTRACT
Two new pyrrolinone-containing lipopeptides, ypaoamides B (1) and C (2), were isolated from an Okeania sp. marine cyanobacterium collected in Okinawa. Their structures were determined by spectroscopic analysis and Marfey's analysis of acid hydrolysates. Ypaoamides B (1) and C (2) stimulated glucose uptake in cultured rat L6 myotubes. In particular, ypaoamide B (1) showed potent activity and activated AMP-activated protein kinase.
Subject(s)
Aquatic Organisms/chemistry , Cyanobacteria/chemistry , Lipopeptides/chemistry , Pyrrolidines/chemistry , Animals , Cell Line , Drug Screening Assays, Antitumor/methods , Rats , Structure-Activity RelationshipABSTRACT
Three new compounds of the malyngamide series, 6,8-di-O-acetylmalyngamide 2 (1), 6-O-acetylmalyngamide 2 (2), and N-demethyl-isomalyngamide I (3), were isolated from the marine cyanobacterium Moorea producens. Their structures were determined by spectroscopic analysis and chemical derivatization and degradation. These compounds stimulated glucose uptake in cultured L6 myotubes. In particular, 6,8-di-O-acetylmalyngamide 2 (1) showed potent activity and activated adenosine monophosphate-activated protein kinase (AMPK).
Subject(s)
Amides/chemistry , Aquatic Organisms , Cyanobacteria/chemistry , Lipopeptides/chemistry , Pyrroles/chemistry , Amides/pharmacology , Animals , Blood Glucose/drug effects , Lipopeptides/pharmacology , Magnetic Resonance Spectroscopy , Molecular Structure , Pyrroles/pharmacology , Structure-Activity RelationshipABSTRACT
Kohamamides A, B, and C (1-3), new cyclic depsipeptides that belong to the kulolide superfamily, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions. Kohamamide B (2) exhibited moderate cytotoxicity against HL60 cells. Although many natural products in the kulolide superfamily have been isolated from cyanobacteria collected in various parts of the world, kohamamides 1-3 are the first members to be isolated from the East Asian marine environment. In addition, unlike other members of this superfamily, kohamamides 1-3 contain a Leu residue adjacent to the Pro residue, rather than another lipophilic amino acid.
Subject(s)
Cyanobacteria/chemistry , Depsipeptides/isolation & purification , Depsipeptides/chemistry , Drug Screening Assays, Antitumor , HL-60 Cells , Humans , Leucine/chemistry , Marine Biology , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Peptides, Cyclic/chemistry , Proline/chemistry , Structure-Activity RelationshipABSTRACT
Biseokeaniamides A, B, and C (1-3), structurally novel sterol O-acyltransferase (SOAT) inhibitors, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions. Biseokeaniamide B (2) exhibited moderate cytotoxicity against human HeLa cancer cells, and compounds 1-3 inhibited both SOAT1 and SOAT2, not only at an enzyme level but also at a cellular level. Biseokeaniamides (1-3) are the first linear lipopeptides that have been shown to exhibit SOAT-inhibitory activity.
Subject(s)
Antineoplastic Agents/isolation & purification , Antineoplastic Agents/pharmacology , Cyanobacteria/chemistry , Lipopeptides/isolation & purification , Lipopeptides/pharmacology , Sterol O-Acyltransferase/antagonists & inhibitors , Antineoplastic Agents/chemistry , Caspase 3/metabolism , HeLa Cells , Humans , Lipopeptides/chemistry , Marine Biology , Molecular Structure , Nuclear Magnetic Resonance, BiomolecularABSTRACT
In the search for new antiprotozoal substances, hoshinolactam, an antitrypanosomal lactam, was isolated from a marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configuration was determined by the first total synthesis. Hoshinolactam showed potent antitrypanosomal activity with an IC50 value of 3.9 nM without cytotoxicity against human fetal lung fibroblast MRC-5 cells (IC50 > 25 µM).
Subject(s)
Cyanobacteria/chemistry , Lactams/chemical synthesis , Lactams/isolation & purification , Trypanocidal Agents/chemical synthesis , Trypanocidal Agents/isolation & purification , Aquatic Organisms , Cell Line , Cell Survival/drug effects , Fibroblasts/cytology , Fibroblasts/drug effects , Humans , Inhibitory Concentration 50 , Lung/cytology , StereoisomerismABSTRACT
Kanamienamide, an enamide with an enol ether, was isolated from the marine cyanobacterium Moorea bouillonii. The gross structure was established by spectroscopic analyses, and the relative stereochemistry was elucidated on the basis of the analyses of NOESY correlations and 1H-1H coupling constants. The absolute configuration was determined on the basis of the chiral HPLC analysis of the N-Me-Leu derived from kanamienamide. This is the first report of a natural product that possesses an N-Me-enamide adjacent to an enol ether. Kanamienamide showed growth-inhibitory activity toward HeLa cells with an IC50 value of 2.5 µM and induced apoptosis-like cell death.