Current Search:  Cyanobacteria (x)

View All Items

  • CSV Spreadsheet
(1 - 8 of 8)
Cytotoxin production by a marine Lyngbya strain (cyanobacterium) in a large-scale laboratory bioreactor
Title
Cytotoxin production by a marine Lyngbya strain (cyanobacterium) in a large-scale laboratory bioreactor.
Creator
Armstrong, J. E., Janda, Kathleen E., Alvarado, B., Wright, Amy E.
Date Issued
1991
PURL
http://purl.flvc.org/FCLA/DT/3333194
Subject Headings
Lyngbya, Cyanobacteria, Cytotoxin, Bioreactors
Format
Document (PDF)
Toxic Peptides and Tubular Pili of Bloom-Forming Cyanobacteria
Title
Toxic Peptides and Tubular Pili of Bloom-Forming Cyanobacteria.
Creator
Ricca, John G., Louda, J. W., Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description
Cyanobacteria are ancient prokaryotes that use photosynthesis and an accumulation of other adaptations to dominate aquatic ecosystems around the world. They are thus major contributors to biogeochemical cycling, a threat to human and environmental health, and an intriguing source for novel chemistry. We begin by providing an overview of bloom-forming cyanobacteria and their many toxic metabolites. We then discuss the characterization of some abundant extracellular pili of Microcystis...
Show moreCyanobacteria are ancient prokaryotes that use photosynthesis and an accumulation of other adaptations to dominate aquatic ecosystems around the world. They are thus major contributors to biogeochemical cycling, a threat to human and environmental health, and an intriguing source for novel chemistry. We begin by providing an overview of bloom-forming cyanobacteria and their many toxic metabolites. We then discuss the characterization of some abundant extracellular pili of Microcystis aeruginosa, reporting a 2.4 Å cryoelectron microscopy pilus structure, revealing a novel class of pili that we have termed cyanobacterial tubular (CT) pili. The CT pili in M. aeruginosa were determined to be multi-functional, with a primary role in networking cells and enhancing colony formation, but also in controlling colony buoyancy, enriching iron, and accumulating toxins in the extracellular mucilage. Lastly, we explore the potential of heavy-labeling cyanobacterial cultures for the sake of isolating natural products that can be studied by vibrational spectroscopic imaging. The vibrational spectra of three classes of cyanopeptides along with their heavy-labeled counterparts are reported, and Density Functional Theory calculations are used to describe mode character, clarifying some unexpected changes in vibrational spectra upon heavy-labeling. As a whole, this work offers new insight into cyanobacterial physiology as well as a means to study cyanopeptides with imaging techniques and stable-isotope labeling.
Show less
Date Issued
2024
PURL
http://purl.flvc.org/fau/fd/FA00014490
Subject Headings
Cyanobacteria, Biogeochemical cycles, Microcystis aeruginosa
Format
Document (PDF)
Isolation and structure elucidation of novel compounds from marine cyanobacteria
Title
Isolation and structure elucidation of novel compounds from marine cyanobacteria.
Creator
Meickle, Theresa, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
The work of this dissertation examined the secondary metabolites of several blooms of the marine cyanobacterium Lyngbya collected in Guam and Florida with an emphasis on the isolation and structure elucidation of novel biologically active compounds. The introduction in Chapter One provides a brief history of marine natural products, a description of cyanobacteria and a summary of peptides isolated from Lyngbya collected in the Caribbean. In Chapter Two, a bioassay-guided fractionation of a...
Show moreThe work of this dissertation examined the secondary metabolites of several blooms of the marine cyanobacterium Lyngbya collected in Guam and Florida with an emphasis on the isolation and structure elucidation of novel biologically active compounds. The introduction in Chapter One provides a brief history of marine natural products, a description of cyanobacteria and a summary of peptides isolated from Lyngbya collected in the Caribbean. In Chapter Two, a bioassay-guided fractionation of a Floridian collection of Lyngbya polychroa led to the isolation and structural determination of the cytotoxin desacetylmicrocolin B and the known compounds microcolins A and B. The structures were established by nuclear magnetic resonance (NMR) spectroscopic analysis. All three compounds inhibited the growth of cancer cell lines HT-29 and IMR-32 at nanomolar concentrations. Microcolins A and B were found to have little activity in the ecological assay against the marine fungus Dendryphiella salina. Chapter Three describes the isolation and structure elucidation of the glycosidic, acyl proline derivative tumonoic acid J from a sample Lyngbya sp. collected in Guam. The planar structure was determined by 1D and 2D NMR spectroscopy in conjunction with high resolution-mass spectrometry (HR-MS) data. Tumonoic acid J showed moderate activity in the ecological assay against the marine fungus D. salina. In Chapter Four, NMR-guided fractionation of a Floridian sample of Lyngbya majuscula led to the isolation of two novel cyclic peptides porpoisamides A and B. The planar structures were determined by 1D and 2D NMR spectroscopy with HR-MS data. The absolute configurations of these two compounds were defined through chiral chromatographic methods and derivatization techniques., The porpoisamides showed only moderate activity in cytotoxicity assays against cancer cell lines HCT-116 and U2OS. Finally, Chapter Five examines a potential ecological role of compounds isolated from marine cyanobacte ria. These secondary metabolites may function as chemical defenses against competing microorganisms within marine environments. Compounds isolated from cyanobacteria were tested for anti-fungal activity against the saprophytic marine fungus D. salina. Three of the six compounds tested produced inhibitory activity at or below their natural concentration.
Show less
Date Issued
2010
PURL
http://purl.flvc.org/FAU/2978991
Subject Headings
Sponges, Ecology, Cyanobacteria, Biological control, Aquatic ecology
Format
Document (PDF)
Nutrient manipulation methods for coral reef studies: A critical review and experimental field data
Title
Nutrient manipulation methods for coral reef studies: A critical review and experimental field data.
Creator
Littler, Mark M., Littler, Diane S., Brooks, Barrett L., Lapointe, Brian E.
Date Issued
2006
PURL
http://purl.flvc.org/FCLA/DT/2875927
Subject Headings
Corals, Coral reefs and islands, Algae, Cyanobacteria, Eutrophication
Format
Document (PDF)
Effect of external pH on cyanobacterial pigment expression
Title
Effect of external pH on cyanobacterial pigment expression.
Creator
West, Maria., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
Cyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH
Show moreCyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH <7 are suggested by significantly greater expression of myxoxanthophylls. Direct and indirect physiological costs of altering cell walls may contribute to S. calcicola's depressed growth at acidic pH. Comparison of chlorophylls expression suggests that alkaline rather than neutral external pH is only beneficial for S. calcicola growth in absence of nutrient limitation. While the cyanobacterial biomarker ratio of chlorophylls to echinenone was stable across the pertinent pH range of 6-8, other pigment ratios in S. calcicola were affected by pH with an approximately two week lag between the change of pH and the corresponding change of pigment expression.
Show less
Date Issued
2010
PURL
http://purl.flvc.org/FAU/2795335
Subject Headings
Environmental toxicology, Cyanobacteria, Environmental aspects, Ecosystem management, Vegetation dynamics
Format
Document (PDF)
Nitrogen and phosphorus uptakeand release by the blue-green alga Microcoleus lyngbyaceus
Title
Nitrogen and phosphorus uptakeand release by the blue-green alga Microcoleus lyngbyaceus.
Creator
Zimmermann, Carl F., Harbor Branch Oceanographic Institute
Date Issued
1988
PURL
http://purl.flvc.org/fau/fd/FA00007188
Subject Headings
Indian River (Fla. : Lagoon), Blue-green algae, Cyanobacteria, Microcoleus, Nitrogen, Phosphorus
Format
Document (PDF)
effects of the cyanobacterium Lyngbya majuscula and artificial shading on the seagrass Halodule wrightii
Title
The effects of the cyanobacterium Lyngbya majuscula and artificial shading on the seagrass Halodule wrightii.
Creator
Tiling, Kathryn A., Harriet L. Wilkes Honors College
Abstract/Description
Extensive blooms of the marine cyanobacterium Lyngbya majuscula occurred during 2006 in Halodule wrightii seagrass beds. We examined the effects of L. majuscula blooms on seagrass by removal treatments and assessed if this was primarily an effect of shading by conducting artificial shade treatments. We tested the effects of L. majuscula removal and artificial shading on fifty individual 0.25 m2 experimental seagrass plots infested with L. majuscula in a fully crossed, two-way experiment....
Show moreExtensive blooms of the marine cyanobacterium Lyngbya majuscula occurred during 2006 in Halodule wrightii seagrass beds. We examined the effects of L. majuscula blooms on seagrass by removal treatments and assessed if this was primarily an effect of shading by conducting artificial shade treatments. We tested the effects of L. majuscula removal and artificial shading on fifty individual 0.25 m2 experimental seagrass plots infested with L. majuscula in a fully crossed, two-way experiment. Measurements included blade elongation, biomass, and stem density. Blade lengths of H. wrightii were significantly increased by the presence of artificial shading and L. majuscula. L. majuscula removal resulted in increased below ground biomass in shaded plots, suggesting an increase in stores, when possible, for accelerated recovery following a shading event. Adverse L. majuscula effects occurred after declines in bloom biomass indicating that L. majuscula can have a prolonged negative effect on H. wrightii production.
Show less
Date Issued
2007
PURL
http://purl.flvc.org/FAU/11597
Subject Headings
Cyanobacteria, Biological control, Seagrasses, Physiology, Seagrasses, Effect of salt on, Restoration ecology, Halodule wrightii, Morphology
Format
Document (PDF)
Pigment-based chemotaxonomy of phytoplankton in Lake Okeechobee, Florida and effects of irradiance on cyanobacteria
Title
Pigment-based chemotaxonomy of phytoplankton in Lake Okeechobee, Florida and effects of irradiance on cyanobacteria.
Creator
Skoog, Kathryn Owen., Florida Atlantic University, Louda, J. William
Abstract/Description
The phytoplankton community of Lake Okeechobee, Florida, has been studied and algal divisions were identified. Chemotaxonomy is a process that assigns taxonomic divisions based on ratios of biomarker pigments to chlorophyll, as measured by high performance liquid chromatography (HPLC). Microscopic counts of taxonomic groups were compared to chemotaxonomic groups for lake samples for one year. Lab cultures of cyanobacteria grown at irradiance of 2 to 500 micromoles photons m-2 s-1 (muEinsteins...
Show moreThe phytoplankton community of Lake Okeechobee, Florida, has been studied and algal divisions were identified. Chemotaxonomy is a process that assigns taxonomic divisions based on ratios of biomarker pigments to chlorophyll, as measured by high performance liquid chromatography (HPLC). Microscopic counts of taxonomic groups were compared to chemotaxonomic groups for lake samples for one year. Lab cultures of cyanobacteria grown at irradiance of 2 to 500 micromoles photons m-2 s-1 (muEinsteins) suggested that internal ratios of chlorophyll to both zeaxanthin and echinenone could be used to estimate abundance of cyanobacteria, as either alone missed certain populations. Lake water samples showed that both methods agreed that diatoms and cyanobacteria were the dominant groups, with moderate number of green algae and few dinoflagellates. HPLC evidence revealed cryptophytes more frequently than did microscopy. This suggested that cryptophytes may be more significant than has been previously reported.
Show less
Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/13044
Subject Headings
Cyanobacteria, Phytoplankton--Florida--Okeechobee, Lake, Plant pigments--Florida--Okeechobee, Lake, Okeechobee, Lake (Fla )
Format
Document (PDF)