Doubly Homologated Tyrosine-Containing Peptides from the Cyanobacterium NIES-4285 and Their Biosynthesis.

Chemical investigation of the cyanobacterium NIES-4285 led to the isolation of six new natural products, microginins 705 (), 719 (), 733A (), 733B (), and 733C (), and anabaenopeptin 885 (), and three known compounds, anabaenopeptins 871 (), B (), and F (). Planar structures and absolute configurations for - were determined by 2D NMR, HRMS, and Marfey's analyses. Microginin 733C (), and anabaenopeptins 871 () and 885 () contained a unique residue of 2-amino-5-(4-hydroxyphenyl)pentanoic acid (Ahppa): doubly homologated tyrosine (di-hTyr).

Antimicrobial and Cytotoxic Effect of Green Algae Isolate on MCF-7 Breast Cancer.

Introduction: Marine algae are increasingly becoming a potential resource for new drugs. In recent decades, including (). Meanwhile, antimicrobial and anticancer agents are the first line of choice for developing alternative compounds, considering the annually increasing resistant events.

Noducyclamides A1-A4, B1, and B2 from the Cyanobacterium sp. NIES-3585.

A chemical investigation of the hydrophilic fraction of a cultured sp. (NIES-3585) afforded six new cyclic lipopeptides, noducyclamides A1-A4 (-) containing 10 amino acid residues and dodecapeptides noducyclamides B1 and B2 ( and ). The planar structures of these lipopeptides were elucidated based on the combination of HRMS and 1D and 2D NMR spectroscopic data analyses.

Cyanoremediation of heavy metals (As(v), Cd(ii), Cr(vi), Pb(ii)) by live cyanobacteria (, and sp.): an eco-sustainable technology.

The cyanoremediation technique for heavy metal (HM) removal from wastewater using live cyanobacteria is promising to reduce the pollution risk both for the environment and human health. In this study, two widely recognized freshwater cyanobacteria, and sp., were used to explore their efficacy in HM (As(v), Cd(ii), Cr(vi), Pb(ii)) removal.

[Up to Date of Cyanobacterial Natural Products].

More than 2000 compounds have been reported from cyanobacteria. The most successful example is dolastatin 10, of which a related compound monomethylauristatin E is used as antibody-drug conjugate (ADC) for Hodgkin lymphoma and systemic anaplastic large cell lymphoma. Recently genome-based analyses by Piel led to the discovery of novel compounds from cyanobacteria.

Syntheses and Biological Activities of Danicalipin A Derivatives.

Synthesis of three derivatives of danicalipin A, tetrachloride, trisulfate and a fluorescent probe was achieved through Wittig reaction strategy. Toxicity of the derivatives against brine shrimp (Artemia salina) as also investigated to provide useful information for the biological activity; i) less chloride derivative showed similar toxicity to danicalipin A, ii) the amphiphilic property, a characteristic feature of danicalipin A, was crucial because trisulfate considerably decreased the toxicity and iii) fluorescent derivative kept brine shrimp toxicity of danicalipin A.

Nostosin G and Spiroidesin B from the Cyanobacterium sp. NIES-1697.

Chemical investigation of the cyanobacterium sp. NIES-1697 afforded nostosin G (), a linear tripeptide, spiroidesin B (), and two known compounds, anabaenopeptins I () and J (). Planar structures and absolute configurations for and were determined by 2D NMR, HRMS, Marfey's methodology, chiral-phase HPLC, and enzymatic degradation.

Argicyclamides A-C Unveil Enzymatic Basis for Guanidine Bis-prenylation.

Guanidine prenylation is an outstanding modification in alkaloid and peptide biosynthesis, but its enzymatic basis has remained elusive. We report the isolation of argicyclamides, a new class of cyanobactins with unique mono- and bis-prenylations on guanidine moieties, from NIES-88. The genetic basis of argicyclamide biosynthesis was established by the heterologous expression and characterization of biosynthetic enzymes including AgcF, a new guanidine prenyltransferase.

Bioactivities of Lyngbyabellins from Cyanobacteria of and Genera.

Cyanobacteria are reported as rich sources of secondary metabolites that provide biological activities such as enzyme inhibition and cytotoxicity. Ten depsipeptide derivatives (lyngbyabellins) were isolated from a Malaysian and a Red Sea sp.: lyngbyabellins G (), O (), P (), H (), A (), 27-deoxylyngbyabellin A (), and homohydroxydolabellin ().

Biosurfactants from Marine Cyanobacteria Collected in Sabah, Malaysia.

Chemical investigation of the organic extract from , collected in Sabah, Malaysia, led to the isolation of three new chlorinated fatty acid amides, columbamides F (), G (), and H (). The planar structures of - were established by a combination of mass spectrometric and NMR spectroscopic analyses. The absolute configuration of was determined by Marfey's analysis of its hydrolysate and chiral-phase HPLC analysis after conversion and esterification with Ohrui's acid, (1,2)-2-(anthracene-2,3-dicarboximido)cyclohexanecarboxylic acid.

Parthenogenetic female populations in the brown alga Scytosiphon lomentaria (Scytosiphonaceae, Ectocarpales): decay of a sexual trait and acquisition of asexual traits.

In isogamous brown algae, the sexuality of populations needs to be tested by laboratory crossing experiments, as the sexes of gametophytes are morphologically indistinguishable. In some cases, gamete fusion is not observed and the precise reproductive mode of the populations is unknown. In the isogamous brown alga Scytosiphon lomentaria in Japan, both asexual (gamete fusion is unobservable) and sexual populations (gamete fusion is observable) have been reported.

Synthesis and Structure-Activity Relationship of Omaezallene Derivatives.

Omaezallene derivatives (nor-bromoallene, nor-bromodiene, and bromoenynes) were successfully synthesized. Their antifouling activity and toxicity to the cypris larvae of the barnacle Amphibalanus amphitrite and ecotoxicity to the marine crustacean Tigriopus japonicus were studied. It was revealed that the two side chains of omaezallene were essential to its antifouling activity because the activities of nor-bromoallene and nor-bromodiene were significantly diminished.

Antioxidants from the Brown Alga .

An investigation of anti-oxidative compounds from the brown alga has led to the isolation and identification of isozonarol, isozonarone, chromazonarol, zonaroic acid and isozonaroic acid. Their structures were identified by comparison of MS and NMR spectra. Full NMR assignment and absolute configuration of isozonaroic acid are described.

Kakeromamide A, a new cyclic pentapeptide inducing astrocyte differentiation isolated from the marine cyanobacterium Moorea bouillonii.

Kakeromamide A (1), a new cyclic pentapeptide encompassing a thiazole ring moiety and a β-amino acid, was isolated from the marine cyanobacterium Moorea bouillonii. Its structure was elucidated by the spectral analysis and the modified Marfey's method. Compound 1 induced differentiation of neural stem cells into astrocytes at the concentration of 10 µM.

Serinolamides and Lyngbyabellins from an Okeania sp. Cyanobacterium Collected from the Red Sea.

NMR- and MS-guided fractionation of an extract of an Okeania sp. marine cyanobacterium, collected from the Red Sea, led to the isolation of four new metabolites, including serinolamides C (1) and D (2) and lyngbyabellins O (3) and P (4), together with the three known substances lyngbyabellins F (5) and G (6) and dolastatin 16 (7). The planar structures of the new compounds were determined using NMR and MS analyses.

New Marine Antifouling Compounds from the Red Alga Laurencia sp.

Six new compounds, omaezol, intricatriol, hachijojimallenes A and B, debromoaplysinal, and 11,12-dihydro-3-hydroxyretinol have been isolated from four collections of sp. These structures were determined by MS and NMR analyses. Their antifouling activities were evaluated together with eight previously known compounds isolated from the same samples.

Columbamides D and E: Chlorinated Fatty Acid Amides from the Marine Cyanobacterium Moorea bouillonii Collected in Malaysia.

Two new chlorinated fatty acid amides, columbamides D (1) and E (2), along with apratoxins A and C and wewakazole, were isolated from the organic extract of a Moorea bouillonii sample from Sabah, Malaysia. Structure elucidation was accomplished by a combination of MS and NMR analyses. The total synthesis of all four stereoisomers of 1 was completed, and the absolute configuration was determined by chiral-phase HPLC and Marfey's analysis.

A quantitative shRNA screen identifies ATP1A1 as a gene that regulates cytotoxicity by aurilide B.

Genome-wide RNA interference (RNAi) with pooled and barcoded short-hairpin RNA (shRNA) libraries provides a powerful tool for identifying cellular components that are relevant to the modes/mechanisms of action (MoA) of bioactive compounds. shRNAs that affect cellular sensitivity to a given compound can be identified by deep sequencing of shRNA-specific barcodes. We used multiplex barcode sequencing technology by adding sample-specific index tags to PCR primers during sequence library preparation, enabling parallel analysis of multiple samples.

Total synthesis and biological activity of dolastatin 16.

The total synthesis of dolastatin 16, a macrocyclic depsipeptide first isolated from the sea hare Dolabella auricularia as a potential antineoplastic metabolite by Pettit et al., was achieved in a convergent manner. Dolastatin 16 was reported by Tan to exhibit strong antifouling activity, and thus shows promise for inhibiting the attachment of marine benthic organisms such as Amphibalanus amphitrite to ships and submerged artificial structures.

Wewakazole B, a Cytotoxic Cyanobactin from the Cyanobacterium Moorea producens Collected in the Red Sea.

A mass spectrometry (MS)-guided isolation has led to the purification of a new cyanobactin, wewakazole B (1), along with the known compound curacin D from a Red Sea Moorea producens. The planar structure of 1 was elucidated using a combination of NMR and MS techniques. After ozonolysis and acid hydrolysis, the absolute configurations of the amino acid components of 1 were determined by chiral-phase LC-MS and HPLC analyses.

cDNA cloning and characterization of vanadium-dependent bromoperoxidases from the red alga Laurencia nipponica.

The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their Km values for Br(-) were significantly lower than other red algal VBPOs.

Alnuheptanoid A: a new diarylheptanoid derivative from Alnus japonica.

Extensive chromatographic investigation of the ethanolic extract of Alnus japonica Steud stem bark led to the isolation of a new diarylheptanoid named alnuheptanoid A [(5S)-7-(3,4-dihydroxyphenyl)-1-(4-hydroxyphenyl)-5-methoxyheptan-3-one] (8), together with seven known diarylheptanoid derivatives: platyphyllenone (5), (5S)-1,7-bis(4-hydroxyphenyl)-5-methoxyheptan-3-one (6), 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-4-hepten-3-one (7), hirsutenone (9), (5R)-O-methylhirsutanonol (10), hirsutanonol (11) and oregonin (13), three triterpenes: α-amyrin (1), betulinaldehyde (3) and betulinic acid (4), and two sterols: β-sitosterol (2) and daucosterol (12). Compound 6 was isolated for the first time from natural source. The structures of the isolated compounds were determined on the basis of spectroscopic measurements (UV, IR, HR-ESI-MS, 1D and 2D NMR).

Omaezallene from red alga Laurencia sp.: structure elucidation, total synthesis, and antifouling activity.

Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurencia sp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes.

Bouillonamide: a mixed polyketide-peptide cytotoxin from the marine cyanobacterium Moorea bouillonii.

The tropical marine cyanobacterium, Moorea bouillonii, has gained recent attention as a rich source of bioactive natural products. Continued chemical investigation of this cyanobacterium, collected from New Britain, Papua New Guinea, yielded a novel cytotoxic cyclic depsipeptide, bouillonamide (1), along with previously reported molecules, ulongamide A and apratoxin A. Planar structure of bouillonamide was established by extensive 1D and 2D NMR experiments, including multi-edited HSQC, TOCSY, HBMC, and ROESY experiments.

Thrombin inhibitors from the freshwater cyanobacterium Anabaena compacta.

Bioassay-guided investigation of the cyanobacterium Anabaena compacta extracts afforded spumigin J (1) and the known thrombin inhibitor spumigin A (2). The absolute configuration of 1 was analyzed by advanced Marfey's methodology. Compounds 1 and 2 inhibited thrombin with EC(50) values of 4.