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1.
Lik Tong Tan Ashootosh Tripathi Mui Gek Lim Gary H. Dickinson Serina Siew Chen Lee 《Biofouling》2013,29(6):685-695
Filamentous benthic marine cyanobacteria are a prolific source of structurally unique bioactive secondary metabolites. A total of 12 secondary metabolites, belonging to the mixed polyketide–polypeptide structural class, were isolated from the marine cyanobacterium, Lyngbya majuscula, and were tested to determine if they showed activity against barnacle larval settlement. The assays revealed four compounds, dolastatin 16 (1), hantupeptin C (4), majusculamide A (10), and isomalyngamide A (12), that showed moderate to potent anti-larval settlement activities, with EC50 values ranging from 0.003 to 10.6 μg ml?1. In addition, field testing conducted over a period of 28 days (using the modified Phytagel? method) based on the cyanobacterial compound, dolastatin 16, showed significantly reduced barnacle settlement as compared to controls at all the concentrations tested. The results of this study highlight the importance of marine cyanobacteria as an underexplored source of potential environmentally friendly antifoulants. 相似文献
2.
The Everglades in South Florida are a unique ecological system. As a result of the widespread use of pesticides and herbicides in agricultural areas upstream from these wetlands, there is a serious potential for pollution problems in the Everglades. The purpose of this study was to evaluate the ability of indigenous microbial populations to degrade xenobiotic organic compounds introduced by agricultural and other activities. Such biodegradation may facilitate the remediation of contaminated soils and water in the Everglades. The model compound selected in this study is 4-nitrophenol, a chemical commonly used in the manufacture of pesticides. The mineralization of 4-nitrophenol at various concentrations was studied in soils collected from the Everglades. At concentrations of 10 and 100 microg/g soil, considerable mineralization occurred within a week. At a higher concentration, i.e., 10 mg/g soil, however, no mineralization of 4-nitrophenol occurred over a 4-month period; such a high concentration apparently produced an inhibitory effect. The rate and extent of 4-nitrophenol mineralization was enhanced on inoculation with previously isolated nitrophenol-degrading microorganisms. The maximum mineralization extent measured, however, was less than 30% suggesting conversion to biomass and/or unidentified intermediate products. These results indicate the potential for natural mechanisms to mitigate the adverse effects of xenobiotic pollutants in a complex system such as the Everglades. 相似文献
3.
Pedro N. Le?o Margarida Costa Vitor Ramos Alban R. Pereira Virgínia C. Fernandes Valentina F. Domingues William H. Gerwick Vitor M. Vasconcelos Rosário Martins 《PloS one》2013,8(7)
Cyanobacteria are widely recognized as a valuable source of bioactive metabolites. The majority of such compounds have been isolated from so-called complex cyanobacteria, such as filamentous or colonial forms, which usually display a larger number of biosynthetic gene clusters in their genomes, when compared to free-living unicellular forms. Nevertheless, picocyanobacteria are also known to have potential to produce bioactive natural products. Here, we report the isolation of hierridin B from the marine picocyanobacterium Cyanobium sp. LEGE 06113. This compound had previously been isolated from the filamentous epiphytic cyanobacterium Phormidium ectocarpi SAG 60.90, and had been shown to possess antiplasmodial activity. A phylogenetic analysis of the 16S rRNA gene from both strains confirmed that these cyanobacteria derive from different evolutionary lineages. We further investigated the biological activity of hierridin B, and tested its cytotoxicity towards a panel of human cancer cell lines; it showed selective cytotoxicity towards HT-29 colon adenocarcinoma cells. 相似文献
4.
Daniel L. Childers 《Hydrobiologia》2006,569(1):531-544
This paper synthesizes research conducted dusring the first 5–6 years of the Florida Coastal Everglades Long-Term Ecological
Research Program (FCE LTER). My objectives are to review our research to date, and to present a new central theme and conceptual
approach for future research. Our research has focused on understanding how dissolved organic matter (DOM) from upstream oligotrophic
marshes interacted with a marine source of the limiting nutrient, phosphorus (P), to control productivity in the oligohaline
estuarine ecotone. We have been working along freshwater to marine transects in two drainage basins located in Everglades
National Park (ENP). The Shark River Slough transect (SRS) has a direct connection to the Gulf of Mexico, providing this estuarine
ecotone with a source of marine P. The oligohaline ecotone along our southern Everglades transect (TS/Ph), however, is separated
from this marine P source by the Florida Bay estuary. We originally hypothesized an ecosystem productivity peak in the SRS
ecotone, driven by the interaction of marine P and Everglades DOM, but no such productivity peak in the TS/Ph ecotone because
of this lack of marine P. Our research to date has tended to show the opposite pattern, however, with many ecosystem components
showing enhanced productivity in the TS/Ph ecotone, but not in the SRS ecotone. Water column P concentrations followed a similar
pattern, with unexpectedly high P in the TS/Ph ecotone during the dry season. Our organic geochemical research has shown that
Everglades DOM is more refractory than originally hypothesized. We have also begun to understand the importance of detrital
organic matter production and transport to ecotone dynamics and as the base of aquatic food webs. Our future research will
build on this substantial body of knowledge about these oligotrophic estuaries. We will direct our efforts more strongly on
biophysical dynamics in the oligohaline ecotone regions. Specifically, we will be focusing on inputs to these regions from
four primary water sources: freshwater Everglades runoff, net precipitation, marine inputs, and groundwater. We are hypothesizing
that dry season groundwater inputs of P will be particularly important to TS/Ph ecotone dynamics because of longer water residence
times in this area. Our organic geochemical, biogeochemical, and ecosystem energetics work will focus more strongly on the
importance of detrital organics and will take advantage of a key Everglades Restoration project, scheduled for 2008 or 2009,
that will increase freshwater inputs to our SRS transect only. Finally, we will also begin to investigate the human dimensions
of restoration, and of a growing population in south Florida that will become increasingly dependent on the Everglades for
critical ecosystem services (including fresh water) even as its growth presents challenges to Everglades sustainability. 相似文献
5.
Biodegradation of 4-nitrophenol by indigenous microbial populations in Everglades soils 总被引:2,自引:0,他引:2
The Everglades in South Florida are a unique ecologicalsystem. As a result of the widespread use of pesticides andherbicides in agricultural areas upstream from these wetlands,there is a serious potential for pollution problems in theEverglades. The purpose of this study was to evaluate theability of indigenous microbial populations to degradexenobiotic organic compounds introduced by agricultural andother activities. Such biodegradation may facilitate theremediation of contaminated soils and water in the Everglades.The model compound selected in this study is 4-nitrophenol, achemical commonly used in the manufacture of pesticides. Themineralization of 4-nitrophenol at various concentrations wasstudied in soils collected from the Everglades. Atconcentrations of 10 and 100 µg/g soil, considerablemineralization occurred within a week. At a higherconcentration, i.e., 10 mg/g soil, however, no mineralizationof 4-nitrophenol occurred over a 4-month period; such a highconcentration apparently produced an inhibitory effect. Therate and extent of 4-nitrophenol mineralization was enhancedon inoculation with previously isolated nitrophenol-degradingmicroorganisms. The maximum mineralization extent measured,however, was less than 30% suggesting conversion to biomassand/or unidentified intermediate products. These resultsindicate the potential for natural mechanisms to mitigate theadverse effects of xenobiotic pollutants in a complex systemsuch as the Everglades. 相似文献
6.
The anti-estrogenic substance tamoxifen is effective in the adjuvant therapy applied in human breast cancer. Since it partly exhibits estrogenic activity and has serious side-effects, however, pure anti-estrogenic compounds are being sought. In our experimental study, we compared the anti-proliferative effect of estradiol and 13 endogenous estradiol metabolites on human breast cancer cells with the effect of tamoxifen. We used MCF-7 and MDA-MB 231, the well-established estrogen receptor-positive and -negative cell lines. 4-hydroxytamoxifen, the active metabolite of tamoxifen, estradiol and 13 estradiol metabolites were tested in concentrations ranging from 3.1 to 100 microM. Incubation time was 4 days and cell proliferation was measured by means of the ATP chemosensitivity test. 4-hydroxytamoxifen showed an IC50 value of 27 microM and 18 microM in MCF-7 and MDA-MB 231 cells, respectively. Estradiol and its metabolites were anti-proliferative in both cell lines. A few A-ring metabolites were more effective in inhibiting cell proliferation than D-ring metabolites and the parent substance 17beta-estradiol. 4-OHE1, 2-MeOE1 and 2-MeOE2 were as effective in both cell lines as tamoxifen. For the first time it has been demonstrated that endogenous estradiol metabolites are equally anti-proliferative as tamoxifen in the context of human breast cancer cells. Since some of these metabolites exhibit no estrogenic activity, they are likely to be valuable in clinical studies of chemoprevention and adjuvant therapy of breast cancer. 相似文献
7.
Besarhanamides A (1) and B (2) are fatty acid amides purified from the marine cyanobacterium, Lyngbya majuscula, collected from Pulau Hantu, Singapore. The structure determination of these secondary metabolites was carried out using extensive 2D NMR spectral data as well as chemical manipulations including the Marfey's method. In addition, besarhanamide A exhibited moderate toxicity with LD(50) at 13 microM in the brine shrimp toxicity bioassay. 相似文献
8.
Berry JP Gantar M Gibbs PD Schmale MC 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2007,145(1):61-72
The zebrafish (Danio rerio) embryo has emerged as an important model of vertebrate development. As such, this model system is finding utility in the investigation of toxic agents that inhibit, or otherwise interfere with, developmental processes (i.e. developmental toxins), including compounds that have potential relevance to both human and environmental health, as well as biomedicine. Recently, this system has been applied increasingly to the study of microbial toxins, and more specifically, as an aquatic animal model, has been employed to investigate toxins from marine and freshwater microalgae, including those classified among the so-called "harmful algal blooms" (HABs). We have developed this system for identification and characterization of toxins from cyanobacteria (i.e. "blue-green algae") isolated from the Florida Everglades and other freshwater sources in South and Central Florida. Here we review the use of this system as it has been applied generally to the investigation of toxins from marine and freshwater microalgae, and illustrate this utility as we have applied it to the detection, bioassay-guided fractionation and subsequent characterization of developmental toxins from freshwater cyanobacteria. 相似文献
9.
Cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. The ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitors can be potential anticancer agents. Cyanobacteria have been shown to be a rich source of highly effective inhibitors of proteases. A proteasome inhibitor was screened from an extract of the culture of Scytonema hofmanni on the basis of its inhibitory activity, which led to the isolation of nostodione A with an IC(50) value of 50 microM. Its structure was determined by spectroscopic methods such as 1H-NMR and ESI-MS spectral analyses. 相似文献
10.
Marine cyanobacteria are a rich source of complex bioactive secondary metabolites which derive from mixed biosynthetic pathways. Recently, several marine cyanobacterial natural products have garnered much attention due to their intriguing structures and exciting anti-proliferative or cancer cell toxic activities. Several other recently discovered secondary metabolites exhibit insightful neurotoxic activities whereas others are showing pronounced anti-inflammatory activity. A number of anti-infective compounds displaying activity against neglected diseases have also been identified, which include viridamides A and B, gallinamide A, dragonamide E, and the almiramides. 相似文献
11.
Castiglioni B Rizzi E Frosini A Sivonen K Rajaniemi P Rantala A Mugnai MA Ventura S Wilmotte A Boutte C Grubisic S Balthasart P Consolandi C Bordoni R Mezzelani A Battaglia C De Bellis G 《Applied and environmental microbiology》2004,70(12):7161-7172
The cyanobacteria are photosynthetic prokaryotes of significant ecological and biotechnological interest, since they strongly contribute to primary production and are a rich source of bioactive compounds. In eutrophic fresh and brackish waters, their mass occurrences (water blooms) are often toxic and constitute a high potential risk for human health. Therefore, rapid and reliable identification of cyanobacterial species in complex environmental samples is important. Here we describe the development and validation of a microarray for the identification of cyanobacteria in aquatic environments. Our approach is based on the use of a ligation detection reaction coupled to a universal array. Probes were designed for detecting 19 cyanobacterial groups including Anabaena/Aphanizomenon, Calothrix, Cylindrospermopsis, Cylindrospermum, Gloeothece, halotolerants, Leptolyngbya, Palau Lyngbya, Microcystis, Nodularia, Nostoc, Planktothrix, Antarctic Phormidium, Prochlorococcus, Spirulina, Synechococcus, Synechocystis, Trichodesmium, and Woronichinia. These groups were identified based on an alignment of over 300 cyanobacterial 16S rRNA sequences. For validation of the microarrays, 95 samples (24 axenic strains from culture collections, 27 isolated strains, and 44 cloned fragments recovered from environmental samples) were tested. The results demonstrated a high discriminative power and sensitivity to 1 fmol of the PCR-amplified 16S rRNA gene. Accurate identification of target strains was also achieved with unbalanced mixes of PCR amplicons from different cyanobacteria and an environmental sample. Our universal array method shows great potential for rapid and reliable identification of cyanobacteria. It can be easily adapted to future development and could thus be applied both in research and environmental monitoring. 相似文献
12.
Spatial, geomorphological, and seasonal variability of CDOM in estuaries of the Florida Coastal Everglades 总被引:1,自引:1,他引:0
This paper demonstrates the usefulness of fluorescence techniques for long-term monitoring and assessment of the dynamics
(sources, transport and fate) of chromophoric dissolved organic matter (CDOM) in highly compartmentalized estuarine regions
with non-point water sources. Water samples were collected monthly from a total of 73 sampling stations in the Florida Coastal
Everglades (FCE) estuaries during 2001 and 2002. Spatial and seasonal variability of CDOM characteristics were investigated
for geomorphologically distinct sub-regions within Florida Bay (FB), the Ten Thousand Islands (TTI), and Whitewater Bay (WWB).
These variations were observed in both quantity and quality of CDOM. TOC concentrations in the FCE estuaries were generally
higher during the wet season (June–October), reflecting high freshwater loadings from the Everglades in TTI, and a high primary
productivity of marine biomass in FB. Fluorescence parameters suggested that the CDOM in FB is mainly of marine/microbial
origin, while for TTI and WWB a terrestrial origin from Everglades marsh plants and mangroves was evident. Variations in CDOM
quality seemed mainly controlled by tidal exchange/mixing of Everglades freshwater with Florida Shelf waters, tidally controlled
releases of CDOM from fringe mangroves, primary productivity of marine vegetation in FB and diagenetic processes such as photodegradation
(particularly for WWB). The source and dynamics of CDOM in these subtropical estuaries is complex and found to be influenced
by many factors including hydrology, geomorphology, vegetation cover, landuse and biogeochemical processes. Simple, easy to
measure, high sample throughput fluorescence parameters for surface waters can add valuable information on CDOM dynamics to
long-term water quality studies which can not be obtained from quantitative determinations alone. 相似文献
13.
Production of toxic secondary metabolites by cyanobacteria, collectively referred to as cyanotoxins, has been well described for eutrophied water bodies around the world. However, cohesive cyanobacterial mats also comprise a significant amount of biomass in subtropical oligotrophic wetlands. As these habitats generally do not support much secondary production, cyanotoxins, coupled with other physiological attributes of cyanobacteria, may be contributing to the minimized consumer biomass. Periphyton from the Florida Everglades has a diverse and abundant cyanobacterial assemblage whose species produce toxic metabolites; therefore, by screening periphyton representative of the greater Everglades ecosystem, six different cyanotoxins and one toxin (domoic acid) produced by diatoms were identified, ranging in content from 3 × 10?9 to 1.3 × 10?6 (g · g?1), with saxitoxin, microcystin, and anatoxin‐a being the most common. While content of toxins were generally low, when coupled with the tremendous periphyton biomass (3–3,000 g · m?2), a significant amount of cyanotoxins may be present. While the direct effects of the toxins identified here on the local grazing community need to be determined, the screening process utilized proved effective in showing the broad potential of periphyton to produce a variety of toxins. 相似文献
14.
15.
Purification and characterization of a secreted recombinant phosphotriesterase (parathion hydrolase) from Streptomyces lividans. 总被引:4,自引:0,他引:4
A heterologous phosphotriesterase (parathion hydrolase), previously cloned from a Flavobacterium species into Streptomyces lividans, was secreted at high levels and purified to homogeneity. N-terminal analysis revealed that it had been processed in the same manner as the native membrane-bound Flavobacterium hydrolase. The enzyme consisted of a single polypeptide with an apparent molecular weight of 35,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Substrate specificity studies showed Kms of 68 microM for parathion, 46 microM for O-ethyl O-p-nitrophenyl phenylphosphonothioate, 599 microM for methyl parathion, and 357 microM for p-nitrophenyl ethyl(phenyl)phosphinate. Temperature and pH optima were 45 degrees C and 9.0, respectively. The purified enzyme was inhibited by 1 mM dithiothreitol and 1 mM CuSO4. After chelation and inactivation by o-phenanthroline, however, activity could be partially restored by 1 mM CuCl or 1 mM CuSO4. The results showed that the purified recombinant parathion hydrolase has the same characteristics as the native Flavobacterium hydrolase. This system provides a source of milligram quantities of parathion hydrolase for future structural and mechanism studies and has the potential to be used in toxic waste treatment strategies. 相似文献
16.
17.
Vitalini S Beretta G Iriti M Orsenigo S Basilico N Dall'Acqua S Iorizzi M Fico G 《Acta biochimica Polonica》2011,58(2):203-209
Since antiquity, Achillea millefolium L. (Asteraceae) has been used in traditional medicine of several cultures, from Europe to Asia. Its richness in bioactive compounds contributes to a wide range of medicinal properties. In this study, we assessed A. millefolium methanolic extract and its isolated components for free radical scavenging activity against 2,2-diphenyl-pycrilhydrazyl, total antioxidant capacity (based on the reduction of Cu(++) to Cu(+)), and ability to inhibit lipid peroxidation. The activity against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum was also tested. Chlorogenic acid, its derivatives and some flavonoids isolated by semipreparative HPLC and identified by NMR and spectrometric techniques were the major bioactive constituents of the methanolic extract. The latter exhibited significant antioxidant properties, as well as its flavonol glycosides and chlorogenic acids. With regard to the antiplasmodial activity, apigenin 7-glucoside was the most effective compound, followed by luteolin 7-glucoside, whereas chlorogenic acids were completely inactive. On the whole, our results confirmed A. millefolium as an important source of bioactive metabolites, justifying its pharmaceutical and ethnobotanical use. 相似文献
18.
Grindberg RV Ishoey T Brinza D Esquenazi E Coates RC Liu WT Gerwick L Dorrestein PC Pevzner P Lasken R Gerwick WH 《PloS one》2011,6(4):e18565
Filamentous marine cyanobacteria are extraordinarily rich sources of structurally novel, biomedically relevant natural products. To understand their biosynthetic origins as well as produce increased supplies and analog molecules, access to the clustered biosynthetic genes that encode for the assembly enzymes is necessary. Complicating these efforts is the universal presence of heterotrophic bacteria in the cell wall and sheath material of cyanobacteria obtained from the environment and those grown in uni-cyanobacterial culture. Moreover, the high similarity in genetic elements across disparate secondary metabolite biosynthetic pathways renders imprecise current gene cluster targeting strategies and contributes sequence complexity resulting in partial genome coverage. Thus, it was necessary to use a dual-method approach of single-cell genomic sequencing based on multiple displacement amplification (MDA) and metagenomic library screening. Here, we report the identification of the putative apratoxin. A biosynthetic gene cluster, a potent cancer cell cytotoxin with promise for medicinal applications. The roughly 58 kb biosynthetic gene cluster is composed of 12 open reading frames and has a type I modular mixed polyketide synthase/nonribosomal peptide synthetase (PKS/NRPS) organization and features loading and off-loading domain architecture never previously described. Moreover, this work represents the first successful isolation of a complete biosynthetic gene cluster from Lyngbya bouillonii, a tropical marine cyanobacterium renowned for its production of diverse bioactive secondary metabolites. 相似文献
19.
The nonindigenous sacred ibis (Threskiornis aethiopicus) was first discovered breeding in the Florida Everglades in 2005 in the Arthur R. Marshall Loxahatchee National Wildlife
Refuge. Prior to this, sacred ibises were seen periodically throughout South Florida since the mid 1990s, with occasional
confirmed breeding occurrences in Miami-Dade and Palm Beach counties. We used a logistic regression model developed by Allen
(Biol Invasions 8:491–500, 2006) to predict the probability of successful establishment of sacred ibis in the Florida Everglades
ecosystem. Empirical data collected from several sacred ibis nests and chicks were used to validate those findings. The probability
of successful establishment was estimated to be 73%. The physiological condition of nestlings suggested that this species
was able to fledge chicks in good condition, thus adding to the potential to increase their breeding population. Exponential
population growth rates and expanding distribution of the nonindigenous sacred ibis in France demonstrate this species’ potential
for becoming invasive in Florida. We suggest that the most prudent and effective management strategy is eradication of the
few pioneering individuals that are nesting in the Everglades as well as the urban source population. 相似文献
20.
Holly Gaff John Chick Joel Trexler Donald DeAngelis Louis Gross René Salinas 《Hydrobiologia》2004,520(1-3):73-86
We present an evaluation of a spatially explicit, age-structured model created to assess fish density dynamics in the Florida Everglades area. This model, ALFISH, has been used to compare alternative management scenarios for the Florida Everglades region. This area is characterized by periodic dry downs and refloodings. ALFISH uses spatially explicit water depth data to predict patterns of fish density. Here we present a method for calibration of ALFISH, based on information concerning fish movement, pond locations and other field data. With the current information, the greatest coefficient of determination achieved from regressions of ALFISH output to field data is 0.35 for fish density and 0.88 for water depth. The poor predictability of fish density mirrors the empirical findings that hydrology, which is the main driver of the model, only accounts for 20–40% of the variance of fish densities across the Everglades landscape. Sensitivity analyses indicate that fish in this system are very sensitive to frequency, size and location of permanent ponds as well as availability of prey. 相似文献