Publications

sediment toxicity and community composition of benthos and colonized periphyton in the everglades-florida bay transitional zone.	this survey provides information on sediment toxicity and structural characteristics of the macrobenthic and periphytic algal communities at 10 locations in northeast florida bay. whole sediments were not acutely toxic to mysidopsis bahia (marine invertebrate) and hyalella azteca (freshwater invertebrate) relative to reference sediment. survival was between 80% and 100%. community structure of the macrobenthos and algal-periphyton varied spatially. a total of 116 benthic species were identified ...	2004	15217247
pharmacology and toxicology of pahayokolide a, a bioactive metabolite from a freshwater species of lyngbya isolated from the florida everglades.	the genus of filamentous cyanobacteria, lyngbya, has been found to be a rich source of bioactive metabolites. however, identification of such compounds from lyngbya has largely focused on a few marine representatives. here, we report on the pharmacology and toxicology of pahayokolide a from a freshwater isolate, lyngbya sp. strain 15-2, from the florida everglades. specifically, we investigated inhibition of microbial representatives and mammalian cell lines, as well as toxicity of the compound ...	2004	15683832
plankton food web responses to experimental nutrient additions in a subtropical lake.	during two controlled enclosure experiments using water from a subtropical lake, the plankton food web displayed a highly variable response to combined addition of nitrogen and phosphorus. in july, the nutrients stimulated growth of cylindrospermopsis raciborskii, and the biomass of macrozooplankton and microbial food web components did not increase. in october, the same addition of nutrients stimulated growth of small edible lyngbya spp., and there were coincident increases in biomass of macroz ...	2006	16862351
lyngbyastatin 4, a dolastatin 13 analogue with elastase and chymotrypsin inhibitory activity from the marine cyanobacterium lyngbya confervoides.	lyngbyastatin 4 (1), a new depsipeptide containing the unusual amino acid homotyrosine and a 3-amino-6-hydroxy-2-piperidone (ahp) residue, was isolated from a collection of the marine cyanobacterium lyngbya confervoides off the florida atlantic coast. its gross structure was determined by nmr spectroscopy, and the configurations of asymmetric centers were assigned after chiral hplc analysis of hydrolysis products. lyngbyastatin 4 (1) is an analogue of the sea hare isolate dolastatin 13 and sever ...	2007	17253864
structures of pahayokolides a and b, cyclic peptides from a lyngbya sp.	the isolation and structure elucidation of two cyclic peptides, pahayokolides a (1) and b (2), is described. structural features determined for these compounds include a pendent n-acetyl-n-methyl leucine, both e- and z-dehydrobutyrines, a homophenylalanine, and an unusual polyhydroxy amino acid that is most likely of mixed polyketide synthase/nonribosomal peptide synthase origin. these peptides were purified from a new species of cyanobacteria of the genus lyngbya, which was isolated from a peri ...	2007	17432902
lyngbyastatins 5-7, potent elastase inhibitors from floridian marine cyanobacteria, lyngbya spp.	three new analogues of dolastatin 13, termed lyngbyastatins 5-7 ( 1- 3), were isolated from two different collections of marine cyanobacteria, lyngbya spp., from south florida. their planar structures were deduced by a combination of nmr techniques, and the absolute configurations were established by modified marfey's analysis of the acid hydrolyzates. the related cyclodepsipeptide somamide b ( 4), previously reported from a fijian cyanobacterium, has also been found in one of the extracts, and ...	2007	17910513
total structure determination of grassypeptolide, a new marine cyanobacterial cytotoxin.	a collection of the cyanobacterium lyngbya confervoides off grassy key in florida yielded grassypeptolide (1), a 31-membered macrocyclic depsipeptide with unusually high d-amino acid content, two thiazolines, and one beta-amino acid. we report the rigorous 3d structure determination and conformational analysis in solution and solid state by nmr, ms, x-ray crystallography, chemical degradation, and molecular modeling involving distance geometry and restrained molecular dynamics. grassypeptolide ( ...	2008	18220404
dragonamides c and d, linear lipopeptides from the marine cyanobacterium brown lyngbya polychroa.	two new linear lipopeptides, 1 and 2, and a known compound, curacin d, have been isolated from a marine cyanobacterium, brown lyngbya polychroa, collected from hollywood beach, fort lauderdale, florida. their planar structures were elucidated by 1d and 2d nmr techniques, and absolute configurations were assigned using chiral hplc. the new compounds were assigned the trivial names dragonamide c (1) and dragonamide d (2), as their peptide moiety is related to previously reported dragonamides a and ...	2008	18393465
morphological and genetic evidence that the cyanobacterium lyngbya wollei (farlow ex gomont) speziale and dyck encompasses at least two species.	dense blooms of the cyanobacterium lyngbya wollei are increasingly responsible for declining water quality and habitat degradation in numerous springs, rivers, and reservoirs. this research represents the first molecular phylogenetic analysis of l. wollei in comparison with the traditional morphological characterization of this species. specimens were collected from several springs in florida and a reservoir in north carolina. segments of the small-subunit (ssu) rrna and nifh genes were pcr ampl ...	2008	18441114
toxic cyanobacteria in florida waters.	the occurrence of toxic cyanobacterial blooms in florida waters have become more prominent following increased growth, declining groundwater supplies, and identification of impaired surface waters as future drinking water sources. cyanobacterial toxins have been identified in source waters used for drinking water supply and in post-treated drinking water during algal bloom events. algal toxin concentrations in post-treated drinking water have exceeded existing and proposed world health organizat ...	2008	18461767
kempopeptins a and b, serine protease inhibitors with different selectivity profiles from a marine cyanobacterium, lyngbya sp.	two cyclodepsipeptides named kempopeptins a (1) and b (2) were isolated from a collection of a floridian marine cyanobacterium, lyngbya sp., that had previously afforded the structurally related potent elastase inhibitors lyngbyastatin 7 and somamide b. the structures of 1 and 2 were elucidated mainly by 1d and 2d nmr spectroscopy, and the absolute configuration was established by chiral hplc and marfey's analysis of the degradation products. kempopeptin a (1) exhibited an ic50 against elastase ...	2008	18693761
phylogenetic and chemical diversity of three chemotypes of bloom-forming lyngbya species (cyanobacteria: oscillatoriales) from reefs of southeastern florida.	the cyanobacterial genus lyngbya includes free-living, benthic, filamentous cyanobacteria that form periodic nuisance blooms in lagoons, reefs, and estuaries. lyngbya spp. are prolific producers of biologically active compounds that deter grazers and help blooms persist in the marine environment. here, our investigations reveal the presence of three distinct lyngbya species on nearshore reefs in broward county, fl, sampled in 2006 and 2007. with a combination of morphological measurements, molec ...	2009	19270119
isolation and biological evaluation of 8-epi-malyngamide c from the floridian marine cyanobacterium lyngbya majuscula.	a new stereoisomer of malyngamide c, 8-epi-malyngamide c (1), and the known compound lyngbic acid [(4e,7s)-7-methoxytetradec-4-enoic acid] were isolated from a sample of lyngbya majuscula collected near bush key, dry tortugas, florida. the structure of 1 was determined by nmr and ms experiments. the absolute configuration of 1 was determined by selective mitsunobu inversion of c-8 to give malyngamide c, as determined by nmr, ms, and comparison of specific rotation. both 1 and malyngamide c were ...	2010	20166701
intramolecular modulation of serine protease inhibitor activity in a marine cyanobacterium with antifeedant properties.	extracts of the floridian marine cyanobacterium lyngbya cf. confervoides were found to deter feeding by reef fish and sea urchins (diadema antillarum). this antifeedant activity may be a reflection of the secondary metabolite content, known to be comprised of many serine protease inhibitors. further chemical and nmr spectroscopic investigation led us to isolate and structurally characterize a new serine protease inhibitor 1 that is formally derived from an intramolecular condensation of largamid ...	2010	20631871
caylobolide b, a macrolactone from symplostatin 1-producing marine cyanobacteria phormidium spp. from florida.	a phormidium spp. collection from key west, florida, afforded caylobolide b (1), an analogue of the known macrolactone caylobolide a, previously isolated from a lyngbya majuscula collection from the bahamas. the planar structure of 1 was determined using nmr and ms experiments. the relative configuration for subunits c7-c9 and c25-c29 was assigned using kishi's universal nmr database. caylobolide b (1) displayed cytotoxic activity against ht29 colorectal adenocarcinoma and hela cervical carcinom ...	2010	20806908
porpoisamides a and b, two novel epimeric cyclic depsipeptides from a florida keys collection of lyngbya sp.	nmr-guided fractionation of a non-polar extract of a florida keys collection of lyngbya sp. resulted in the isolation of two novel epimeric cyclic depsipeptides, porpoisamides a (1) and b (2). the planar structures of these compounds were determined using nmr spectroscopic techniques. the absolute configurations of amino and hydroxy acid subunits were assigned by enantioselective hplc analysis. these compounds showed weak cytotoxicity towards hct-116 colorectal carcinoma and u2os osteosarcoma ce ...	2011	21705224