| isolation, structure determination, and biological activity of dolastatin 12 and lyngbyastatin 1 from lyngbya majuscula/schizothrix calcicola cyanobacterial assemblages. | lyngbyastatin 1 (1a), a new cytotoxic analogue of dolastatins 12 (2a) and 11 (4), was isolated as an inseparable mixture with its c-15 epimer (1b) from extracts of a lyngbya majuscula/schizothrix calcicola assemblage and a l. majuscula strain collected near guam. dolastatin 12 (2a) was also encountered as an inseparable mixture with its c-15 epimer (2b) in l. majuscula/s. calcicola assemblages. at least one of the compounds in each mixture appeared to exist in solution as a mixture of slowly int ... | 1998 | 9784156 |
| tumonoic acids, novel metabolites from a cyanobacterial assemblage of lyngbya majuscula and schizothrix calcicola. | five new metabolites have been isolated from a lyngbyastatin 1- and dolastatin 12-producing assemblage of lyngbya majuscula and schizothrix calcicola collected at tumon bay, guam. structure elucidation employed 2d nmr techniques and chemical derivatization. these compounds have been assigned the trivial names tumonoic acids a (2), b (1), and c (5); methyl tumonoate a (3), and methyl tumonoate b (4). compounds 1 and 4 were also found in a lyngbyastatin 1-producing strain of l. majuscula from guam ... | 1999 | 10096859 |
| apramides a-g, novel lipopeptides from the marine cyanobacterium lyngbya majuscula. | six new metabolites have been isolated from a lyngbyastatin 2-producing strain of the marine cyanobacterium lyngbya majuscula collected at apra harbor, guam, and their structures elucidated. these linear lipopeptides have been assigned the trivial names apramides a-f (1-6). from a more recent collection of this cyanobacterium, a structurally related compound, apramide g (7), has been found instead of apramides a-f (1-6). structure elucidation of the lipopeptides 1-7 is based on spectroscopic tec ... | 2000 | 10978206 |
| isolation and structure of the cytotoxin lyngbyabellin b and absolute configuration of lyngbyapeptin a from the marine cyanobacterium lyngbya majuscula. | an analogue of the potent microfilament-disrupter lyngbyabellin a (1) has been isolated as a minor metabolite from the marine cyanobacterium lyngbya majuscula collected at apra harbor, guam. it possesses slightly weaker cytotoxicity than 1 and has been named lyngbyabellin b (2). primarily nmr spectroscopy was used to determine its structure. the absolute configuration of 2 has been ascertained by chiral hplc analysis of degradation products and by comparison with lyngbyabellin a (1). the known m ... | 2000 | 11076573 |
| pitipeptolides a and b, new cyclodepsipeptides from the marine cyanobacterium lyngbya majuscula. | two new cyclodepsipeptides have been isolated from a population of the marine cyanobacterium lyngbya majuscula collected at piti bomb holes, guam. they appear to be unique to this particular guamanian collection and have been named pitipeptolides a (1) and b (2). their structures have been elucidated by spectroscopic techniques and by characterization of degradation products. distinctive features include the presence of a 2,2-dimethyl-3-hydroxy-7-octynoic acid residue in 1 and a 2,2-dimethyl-3-h ... | 2001 | 11277744 |
| new apratoxins of marine cyanobacterial origin from guam and palau. | two collections of the marine cyanobacterium lyngbya sp. from guam and palau that both afforded the potent cytotoxin apratoxin a (1) each yielded different structural analogues with lower degrees of methylation. the new apratoxins, termed apratoxins b (2) and c (3), were evaluated for their in vitro cytotoxicity along with semisynthetic e-dehydroapratoxin a (4) to identify key structural elements responsible for the cytotoxicity and to initiate sar studies on this novel family of depsipeptides. ... | 2002 | 11937357 |
| morphological, chemical, and genetic diversity of tropical marine cyanobacteria lyngbya spp. and symploca spp. (oscillatoriales). | although diverse natural products have been isolated from the benthic, filamentous cyanobacterium lyngbya majuscula, it is unclear whether this chemical variation can be used to establish taxonomic relationships among disparate collections. we compared morphological characteristics, secondary-metabolite compositions, and partial 16s ribosomal dna (rdna) sequences among several collections of l. majuscula gomont, lyngbya spp., and symploca spp. from guam and the republic of palau. the morphologic ... | 2004 | 15184125 |
| chemical deterrence of a cyanobacterial metabolite against generalized and specialized grazers. | pitipeptolide a is the major secondary metabolite in a persistent population of the cyanobacterium lyngbya majuscula from guam. because this cyanobacterium is of low preference to many sympatric consumers, we tested the hypothesis that this compound acted as a chemical defense. pitipeptolide a was deterrent to urchins, two species of amphipods, and small herbivorous crabs, whereas it did not deter feeding by the sea hare stylocheilus striatus, which readily consumes cyanobacteria. although our c ... | 2007 | 17063408 |
| apratoxin e, a cytotoxic peptolide from a guamanian collection of the marine cyanobacterium lyngbya bouillonii. | a collection of the marine cyanobacterium lyngbya bouillonii from guam afforded apratoxin e (1), a new peptide-polyketide hybrid of the apratoxin class of cytotoxins. the planar structure of 1 was elucidated by nmr spectroscopic analysis and mass spectrometry. configurational assignments of stereocenters in the peptide portion were made by chiral hplc analysis of the acid hydrolysate. the relative configuration in the polyketide moiety was assigned by comparison of nmr data including proton-prot ... | 2008 | 18461997 |
| lyngbyastatins 8-10, elastase inhibitors with cyclic depsipeptide scaffolds isolated from the marine cyanobacterium lyngbya semiplena. | investigation of an extract from the marine cyanobacterium lyngbya semiplena, collected in tumon bay, guam, led to the identification of three new cyclodepsipeptides, lyngbyastatins 8-10 (1-3). the structures of 1-3 were determined by nmr, ms, esims fragmentation and chemical degradation. compounds 1-3 are closely related to lyngbyastatins 4-7. like the latter compounds, we found 1-3 to inhibit porcine pancreatic elastase, with ic(50) values of 123 nm, 210 nm and 120 nm, respectively. | 2009 | 20098596 |
| cytotoxic halogenated macrolides and modified peptides from the apratoxin-producing marine cyanobacterium lyngbya bouillonii from guam. | collections of the marine cyanobacterium lyngbya bouillonii from shallow patch reefs in apra harbor, guam, afforded three hitherto undescribed analogues of the glycosidic macrolide lyngbyaloside, namely, 2-epi-lyngbyaloside (1) and the regioisomeric 18e- and 18z-lyngbyalosides c (2 and 3). concurrently we discovered two new analogues of the cytoskeletal actin-disrupting lyngbyabellins, 27-deoxylyngbyabellin a (4) and lyngbyabellin j (5), a novel macrolide of the laingolide family, laingolide b ( ... | 2010 | 20704304 |
| pitiprolamide, a proline-rich dolastatin 16 analogue from the marine cyanobacterium lyngbya majuscula from guam. | an unusual cyclic depsipeptide, pitiprolamide (1), was isolated from the marine cyanobacterium lyngbya majuscula collected at piti bomb holes, guam. the structure was deduced using nmr, ms, x-ray crystallography, and enantioselective hplc-ms techniques. remarkably, proline represents half of the residues forming pitiprolamide (1). other distinctive features include a 4-phenylvaline (dolaphenvaline, dpv) moiety initially found in dolastatin 16 and the rare 2,2-dimethyl-3-hydroxyhexanoic acid (dmh ... | 2010 | 21138309 |
| malyngamide 3 and cocosamides a and b from the marine cyanobacterium lyngbya majuscula from cocos lagoon, guam. | malyngamide 3 (1) and cocosamides a (2) and b (3) were isolated from the lipophilic extract of a collection of lyngbya majuscula from cocos lagoon, guam. the planar structures of compounds 1-3 were determined by spectroscopic methods. the absolute configuration of 1 was determined by modified mosher's method, noesy data, and comparison with lyngbic acid (4). the absolute configurations of 2 and 3 were assigned by enantioselective hplc analysis and comparison with the closely related compound pit ... | 2011 | 21341718 |
| pitipeptolides c-f, antimycobacterial cyclodepsipeptides from the marine cyanobacterium lyngbya majuscula from guam. | pitipeptolides a (1) and b (2) are cyclic depsipeptides isolated from the marine cyanobacterium lyngbya majuscula from piti bomb holes, guam. additional analogues have now been isolated by revisiting larger collections of the same cyanobacterium. the four identified analogues, pitipeptolides c-f (3-6), are the tetrahydro analogue (3), an analogue with a lower degree of methylation (4) as well as two homologues (5 and 6) of pitipeptolide a. their structures were elucidated using 2d nmr experiment ... | 2011 | 21843895 |