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Articles 1 - 12 of 12
Full-Text Articles in Life Sciences
Advancing Cyanobacteria Biomass Estimation From Hyperspectral Observations: Demonstrations With Hico And Prisma Imagery, Ryan E. O'Shea, Nima Pahlevan, Brandon Smith, Mariano Bresciani, Todd Egerton, Claudia Giardino, Lin Li, Tim Moore, Antonio Ruiz-Verdu, Steve Ruberg, Stefan G.H. Simis, Richard Stumpf, Diana Vaičiūtė
Advancing Cyanobacteria Biomass Estimation From Hyperspectral Observations: Demonstrations With Hico And Prisma Imagery, Ryan E. O'Shea, Nima Pahlevan, Brandon Smith, Mariano Bresciani, Todd Egerton, Claudia Giardino, Lin Li, Tim Moore, Antonio Ruiz-Verdu, Steve Ruberg, Stefan G.H. Simis, Richard Stumpf, Diana Vaičiūtė
Biological Sciences Faculty Publications
Retrieval of the phycocyanin concentration (PC), a characteristic pigment of, and proxy for, cyanobacteria biomass, from hyperspectral satellite remote sensing measurements is challenging due to uncertainties in the remote sensing reflectance (∆Rrs) resulting from atmospheric correction and instrument radiometric noise. Although several individual algorithms have been proven to capture local variations in cyanobacteria biomass in specific regions, their performance has not been assessed on hyperspectral images from satellite sensors. Our work leverages a machine-learning model, Mixture Density Networks (MDNs), trained on a large (N = 939) dataset of collocated in situ chlorophyll-a concentrations (Chla), …
The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R Michael Mckay
The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R Michael Mckay
Biological Sciences Faculty Publications
Blooms of the toxin-producing cyanobacterium are increasing globally, leading to the loss of ecosystem services, threats to human health, as well as the deaths of pets and husbandry animals. While nutrient availability is a well-known driver of algal biomass, the factors controlling "who" is present in fresh waters are more complicated. possesses multiple strategies to adapt to temperature, light, changes in nutrient chemistry, herbivory, and parasitism that provide a selective advantage over its competitors. Moreover, its ability to alter ecosystem pH provides it a further advantage that helps exclude many of its planktonic competitors. While decades of nutrient monitoring have …
Cpet Is The Phycoerythrobilin Lyase For Cys-165 On Beta-Phycoerythrin From Fremyella Diplosiphon And The Chaperone-Like Protein Cpez Greatly Improves Its Activity., Wendy M. Schluchter, A. A. Nguyen, K. L. Joseph, A. N. Bussell, S. Pokhrel, A. J. Karty, M. C. Kronfel, D. M. Kehoe
Cpet Is The Phycoerythrobilin Lyase For Cys-165 On Beta-Phycoerythrin From Fremyella Diplosiphon And The Chaperone-Like Protein Cpez Greatly Improves Its Activity., Wendy M. Schluchter, A. A. Nguyen, K. L. Joseph, A. N. Bussell, S. Pokhrel, A. J. Karty, M. C. Kronfel, D. M. Kehoe
Biological Sciences Faculty Publications
Bilin lyases are enzymes which ligate linear tetrapyrrole chromophores to specific cysteine residues on light harvesting proteins present in cyanobacteria and red algae. The lyases responsible for chromophorylating the light harvesting protein phycoerythrin (PE) have not been fully characterized. In this study, we explore the role of CpeT, a putative bilin lyase, in the biosynthesis of PE in the cyanobacterium Fremyella diplosiphon. Recombinant protein studies show that CpeT alone can bind phycoerythrobilin (PEB), but CpeZ, a chaperone-like protein, is needed in order to correctly and efficiently attach PEB to the beta-subunit of PE. MS analyses of the recombinant beta-subunit of …
Cpef Is The Bilin Lyase That Ligates The Doubly Linked Phycoerythrobilin On Phycoerythrin In The Cyanobacterium Fremyella Diplosiphon, Wendy M. Schluchter, R. B. Cole, D. M. Kehoe, M. N. Boutaghou, J. A. Karty, A. Gutu, L. S. Hernandez, J. P. Frick, C. V. Hernandez, C. M. Kronfel
Cpef Is The Bilin Lyase That Ligates The Doubly Linked Phycoerythrobilin On Phycoerythrin In The Cyanobacterium Fremyella Diplosiphon, Wendy M. Schluchter, R. B. Cole, D. M. Kehoe, M. N. Boutaghou, J. A. Karty, A. Gutu, L. S. Hernandez, J. P. Frick, C. V. Hernandez, C. M. Kronfel
Biological Sciences Faculty Publications
Phycoerythrin (PE) is a green light-absorbing protein present in the light-harvesting complex of cyanobacteria and red algae. The spectral characteristics of PE are due to its prosthetic groups, or phycoerythrobilins (PEBs), that are covalently attached to the protein chain by specific bilin lyases. Only two PE lyases have been identified and characterized so far, and the other bilin lyases are unknown. Here, using in silico analyses, markerless deletion, biochemical assays with purified and recombinant proteins, and site-directed mutagenesis, we examined the role of a putative lyase-encoding gene, cpeF, in the cyanobacterium Fremyella diplosiphon. Analyzing the phenotype of the cpeF deletion, …
The Roles Of The Chaperone-Like Protein Cpez And The Phycoerythrobilin Lyase Cpey In Phycoerythrin Biogenesis, Wendy M. Schluchter, D. M. Kehoe, J. A. Karty, T. Blensdorf, A. Gutu, J. P. Frick, A. Biswas, C. M. Kronfel
The Roles Of The Chaperone-Like Protein Cpez And The Phycoerythrobilin Lyase Cpey In Phycoerythrin Biogenesis, Wendy M. Schluchter, D. M. Kehoe, J. A. Karty, T. Blensdorf, A. Gutu, J. P. Frick, A. Biswas, C. M. Kronfel
Biological Sciences Faculty Publications
Phycoerythrin (PE) present in the distal ends of light-harvesting phycobilisome rods in Fremyella diplosiphon (Tolypothrix sp. PCC 7601) contains five phycoerythrobilin (PEB) chromophores attached to six cysteine residues for efficient green light capture for photosynthesis. Chromophore ligation on PE subunits occurs through bilin lyase catalyzed reactions, but the characterization of the roles of all bilin lyases for phycoerythrin is not yet complete. To gain a more complete understanding about the individual functions of CpeZ and CpeY in PE biogenesis in cyanobacteria, we examined PE and phycobilisomes purified from wild type F. diplosiphon, cpeZ and cpeY knockout mutants. We find that …
Interplay Between Differentially Expressed Enzymes Contributes To Light Color Acclimation In Marine Synechococcus, Wendy M. Schluchter, D. M. Kehoe, F. Partensky, J. A. Strnat, S. Pokhrel, J. A. A. Karty, L. Garczarek, A. A. Nguyen, J. E. Sanfilippo
Interplay Between Differentially Expressed Enzymes Contributes To Light Color Acclimation In Marine Synechococcus, Wendy M. Schluchter, D. M. Kehoe, F. Partensky, J. A. Strnat, S. Pokhrel, J. A. A. Karty, L. Garczarek, A. A. Nguyen, J. E. Sanfilippo
Biological Sciences Faculty Publications
Marine Synechococcus, a globally important group of cyanobacteria, thrives in various light niches in part due to its varied photosynthetic light-harvesting pigments. Many Synechococcus strains use a process known as chromatic acclimation to optimize the ratio of two chromophores, green-light-absorbing phycoerythrobilin (PEB) and blue-light-absorbing phycourobilin (PUB), within their light-harvesting complexes. A full mechanistic understanding of how Synechococcus cells tune their PEB to PUB ratio during chromatic acclimation has not yet been obtained. Here, we show that interplay between two enzymes named MpeY and MpeZ controls differential PEB and PUB covalent attachment to the same cysteine residue. MpeY attaches PEB to …
Population-Level Coordination Of Pigment Response In Individual Cyanobacterial Cells Under Altered Nitrogen Levels, Jaclyn Murton, Aparna Nagarajan, Amelia Y. Nguyen, Michelle Liberton, Harmony A. Hancock, Himadri B. Pakrasi, Jerilyn A. Timlin
Population-Level Coordination Of Pigment Response In Individual Cyanobacterial Cells Under Altered Nitrogen Levels, Jaclyn Murton, Aparna Nagarajan, Amelia Y. Nguyen, Michelle Liberton, Harmony A. Hancock, Himadri B. Pakrasi, Jerilyn A. Timlin
Biological Sciences Faculty Publications
Cyanobacterial phycobilisome (PBS) pigment-protein complexes harvest light and transfer the energy to reaction centers. Previous ensemble studies have shown that cyanobacteria respond to changes in nutrient availability by modifying the structure of PBS complexes, but this process has not been visualized for individual pigments at the single-cell level due to spectral overlap. We characterized the response of four key photosynthetic pigments to nitrogen depletion and repletion at the subcellular level in individual, live Synechocystis sp. PCC 6803 cells using hyperspectral confocal fluorescence microscopy and multivariate image analysis. Our results revealed that PBS degradation and re-synthesis comprise a rapid response to …
Plasticity Of Total And Intracellular Phosphorus Quotas In Microcystis Aeruginosa Cultures And Lake Erie Algal Assemblages, Robert Michael Mckay, Matthew A. Saxton, Robert J. Arnold, Richard A. Bourbonniere, Steven W. Wilhelm
Plasticity Of Total And Intracellular Phosphorus Quotas In Microcystis Aeruginosa Cultures And Lake Erie Algal Assemblages, Robert Michael Mckay, Matthew A. Saxton, Robert J. Arnold, Richard A. Bourbonniere, Steven W. Wilhelm
Biological Sciences Faculty Publications
Blooms of the potentially toxic cyanobacterium Microcystis are common events globally, and as a result significant resources continue to be dedicated to monitoring and controlling these events. Recent studies have shown that a significant proportion of total cell-associated phosphorus (P) in marine phytoplankton can be surface adsorbed; as a result studies completed to date do not accurately report the P demands of these organisms. In this study we measure the total cell-associated and intracellular P as well as growth rates of two toxic strains of Microcystis aeruginosa Kütz grown under a range of P concentrations. The results show that the …
Cyanobacteria Dominance In The Oligohaline Waters Of Back Bay, Virginia, Harold G. Marshall
Cyanobacteria Dominance In The Oligohaline Waters Of Back Bay, Virginia, Harold G. Marshall
Biological Sciences Faculty Publications
Back Bay and its flora have historically been influenced by the interaction of freshwater flow in combination with frequent intrusion of saline water into its basin. These events have resulted in a dynamic environmental setting influencing the abundance and composition of its phytoplankton community. Dominating these oligohaline waters is a diverse representation and high abundance of freshwater filamentous and colonial cyanobacteria. These include the nonheterocystous Planktolyngbya contorta, Planktolyngbya limnetica, and Pseudanabaena limnetica, taxa implicated as bloom producers in Bay waters with N:P molar ratios ranging from 23:1 to 74:1.
Potential Effects Of Catastrophic Cyanobacteria Blooms On Caribbean Spiny Lobster Population Dynamics In Florida Bay Usa, Donald C. Behringer, Mark J. Butler Iv
Potential Effects Of Catastrophic Cyanobacteria Blooms On Caribbean Spiny Lobster Population Dynamics In Florida Bay Usa, Donald C. Behringer, Mark J. Butler Iv
Biological Sciences Faculty Publications
No abstract provided.
Cascading Disturbances In Florida Bay, Usa: Cyanobacteria Blooms, Sponge Mortality, And Implications For Juvenile Spiny Lobsters Panulirus Argus, Mark J. Butler Iv, John H. Hunt, William F. Herrnkind, Michael J. Childress, Rodney Bertelsen, William Sharp, Thomas Matthews, Jennifer M. Field, Harold G. Marshall
Cascading Disturbances In Florida Bay, Usa: Cyanobacteria Blooms, Sponge Mortality, And Implications For Juvenile Spiny Lobsters Panulirus Argus, Mark J. Butler Iv, John H. Hunt, William F. Herrnkind, Michael J. Childress, Rodney Bertelsen, William Sharp, Thomas Matthews, Jennifer M. Field, Harold G. Marshall
Biological Sciences Faculty Publications
Florida Bay, the shallow lagoon separating mainland Florida and the Florida Keys, USA, is experiencing an unprecedented series of ecological disturbances. In 1991, following reports of other ecosystem perturbations, we observed widespread and persistent blooms of cyanobacteria that coincided with the decimation of sponge communities over hundreds of square kilometers. Juvenile Caribbean spiny lobsters Panulirus argus, among other animals, rely on sponges for shelter; the impact of sponge loss on the abundance of lobsters and their use of shelter, in particular, has been dramatic. The loss of sponges on 27 experimental sites in hard bottom habitat in central Florida Bay …
Phytoplankton Relationships To Water Quality In Lake Drummond And Two Drainage Ditches, Christine G. Phillips, Harold G. Marshall
Phytoplankton Relationships To Water Quality In Lake Drummond And Two Drainage Ditches, Christine G. Phillips, Harold G. Marshall
Biological Sciences Faculty Publications
A twelve-month phytoplankton study was conducted in Lake Drummond and Washington and Jericho Ditches from December 1988 to November 1989. Four dominant phytoplankton groups were identified at these sites. These were the Bacillariophyceae, Cyanophyceae, Cryptophyceae and an autotrophic picoplankton component. Over the past 20 years there has been a decrease in the mean pH levels of Lake Drummond and the replacement of one its former major components, the Chlorophyceae, by the Cyanophyceae. Based on water quality analysis results and species diversity indices, Lake Drummond is classified as in an early eutrophic stage of development.