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Articles 1 - 14 of 14
Full-Text Articles in Ecology and Evolutionary Biology
The Response Of Microcystis And The Microbiome To Exogenous Hydrogen Peroxide, Bryan A. Puma
The Response Of Microcystis And The Microbiome To Exogenous Hydrogen Peroxide, Bryan A. Puma
Masters Theses, 2020-current
Microcystis spp. produce prolific annual blooms in freshwater systems worldwide. The success of these blooms depends heavily on the Microcystis spp. overcoming environmental factors such as oxidative stress caused by reactive oxygen species (ROS) like hydrogen peroxide. Most Microcystis genomes do not contain many genes for responding to oxidative stress, including those that encode the enzyme catalase. Other cyanobacteria such as Prochlorococcus that also lack hydrogen peroxide degrading enzymes have been shown to benefit from partnerships with heterotrophic bacteria. Microcystis spp. may also receive similar benefits from heterotrophic bacteria in the phycosphere. To test this hypothesis, we examined the …
Allelopathic Effect Of Cereal Straw Extracts On Growth Of Raphidocelis Subcapitata And Microcystis Aeruginosa, Holly Wren
Graduate Theses and Dissertations
Harmful algal blooms are increasing in size, duration, and intensity around the globe. For several decades, cereal straws have been recognized as a viable algal control method, though the mechanisms by which cereal straws inhibit algae remain a topic of research. The objectives of this study were to evaluate the effectiveness of decomposing cereal straw extract, particularly rice (Oryza sativa) and barley (Hordeum vulgare) straw extract, to inhibit the green alga Raphidocelis subcapitata or cyanobacteria Microcystis aeruginosa in bioassays and to determine if the effectiveness of decomposing rice straw extract is altered by the presence of natural organic matter or …
An Integrative Investigation Of The Synechococcus A/B Clade During Adaptive Radiation At The Upper Thermal Limit Of Phototrophy, Christopher L. Pierpont
An Integrative Investigation Of The Synechococcus A/B Clade During Adaptive Radiation At The Upper Thermal Limit Of Phototrophy, Christopher L. Pierpont
Graduate Student Theses, Dissertations, & Professional Papers
Thermophilic microorganisms have been scientifically observed since the early nineteenth century and have spurred many questions about the limits of life and the capacity of organisms to survive extreme conditions. Decades of research on thermophile proteins and genomes have yielded several proposed correlates of temperature that may contribute to adaptation of bacteria and archaea to high temperature. However, many of the generalizations reported are drawn from analyses of deeply divergent taxa or from individual case studies in isolation from mesophilic relatives. Members of the Synechococcus A/B (SynAB) group are the only cyanobacteria with members able to grow above 65 °C …
Monitoring Photosynthetic Activity Using In Vivo Chlorophyll A Fluorescence In Microalgae And Cyanobacteria Biofilms In The Nerja Cave (Malaga, Spain), Yolanda Del Rosal, Juan Muñoz-Fernández, Paula S.M. Celis-Plá, Mariona Hernández-Mariné, Félix Álvarez-Gómez, Salvador Merino, Félix L. Figueroa
Monitoring Photosynthetic Activity Using In Vivo Chlorophyll A Fluorescence In Microalgae And Cyanobacteria Biofilms In The Nerja Cave (Malaga, Spain), Yolanda Del Rosal, Juan Muñoz-Fernández, Paula S.M. Celis-Plá, Mariona Hernández-Mariné, Félix Álvarez-Gómez, Salvador Merino, Félix L. Figueroa
International Journal of Speleology
The characterization of the most common photosynthetic biofilms in the Nerja Cave by the continuous monitoring of the in vivo chlorophyll a (Chl a) fluorescence and the incorporation of the irradiance as a new environmental variable related to previous studies in the cave, have allowed us to improve our knowledge about the photosynthetic pattern of the biofilms of the cave. Effective quantum yield (ΔF/Fm′) and relative electron transport rate (rETR) were determined during periods of the light, whereas the maximal quantum yield (Fv /Fm) was determined during dark periods. Increases in …
Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters, M. Consuelo Gazitúa, Dean R. Vik, Simon Roux, Ann C. Gregory, Benjamin Bolduc, Brittany Widner, Margaret R. Mulholland, Steven J. Hallam, Osvaldo Ulloa, Matthew B. Sullivan
Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters, M. Consuelo Gazitúa, Dean R. Vik, Simon Roux, Ann C. Gregory, Benjamin Bolduc, Brittany Widner, Margaret R. Mulholland, Steven J. Hallam, Osvaldo Ulloa, Matthew B. Sullivan
OES Faculty Publications
Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ …
Urea As An Effective Nitrogen Source For Cyanobacteria, Kevin J. Erratt
Urea As An Effective Nitrogen Source For Cyanobacteria, Kevin J. Erratt
Electronic Thesis and Dissertation Repository
Urea use has grown substantially in the past half-century, with urea now accounting for > 50% of nitrogen fertilizer applications worldwide. The shift from inorganic nitrogen fertilizers to urea-based sources has coincided with the reappearance of cyanobacteria blooms in freshwaters. Here, we examined urea as a nitrogen source for three bloom-forming cyanobacteria species. We found that (1) urea was consumed more rapidly relative to inorganic nitrogen substrates, suggesting that cyanobacteria exhibit a preference for urea; (2) urea was consumed in excess of cellular requirements; and (3) urea may offer cyanobacteria a competitive edge over eukaryotic algae by enhancing light absorption capabilities. …
Contributions Of Gene Copy Number Variation To Genome Evolution And Local Adaptation Of The Cyanobacterium Acaryochloris, Amy L. Gallagher
Contributions Of Gene Copy Number Variation To Genome Evolution And Local Adaptation Of The Cyanobacterium Acaryochloris, Amy L. Gallagher
Graduate Student Theses, Dissertations, & Professional Papers
Acaryochloris is a recently discovered genus of cyanobacteria, unique in its use of an uncommon chlorophyll as its major photosynthetic pigment, and in its peculiar genome dynamics. Members of this genus exhibit increased genic copy number variation (CNV), which is thought to be primarily derived from gene duplications and horizontal gene transfer (HGT). Acaryochloris provides an ideal system to explore mechanisms behind maintenance of gene duplicates and the influence of CNV in local adaptation. Here, I propose a mechanism for retention of gene duplicates of the bacterial recombinase, RecA, in Acaryochloris genomes and provide preliminary evidence that these paralogs are …
Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li
Doctoral Dissertations
Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this tetrameric …
Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins
Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins
OES Faculty Publications
Marine dinitrogen (N2)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO2) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N2 fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N2-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N2-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient …
The Role Of Nitrogen And Phosphorus In The Growth, Toxicity, And Distribution Of The Toxic Cyanobacteria, Microcystis Aeruginosa, James Parrish
The Role Of Nitrogen And Phosphorus In The Growth, Toxicity, And Distribution Of The Toxic Cyanobacteria, Microcystis Aeruginosa, James Parrish
Master's Projects and Capstones
Microcystis aeruginosa is among the most common harmful algal-blooming species in the world. Potent microcystins released by M. aeruginosa have been linked to liver failure and death in aquatic mammals, like the endangered California sea otter, and provide a serious public health risk to humans. Once characterized as a freshwater problem, M. aeruginosa is expanding on a global scale, making persistent returns in freshwater, brackish, and coastal marine ecosystems. Though commonly observed dominating aquatic ecosystems in low N:P atomic ratios less than 44:1, the reliability of N:P ratios as a tool for managing and predicting M. aeruginosa blooms is explored …
The Movement Of Escherichia Coli And Enterococci Among Beach Sand, Lyngbya Wollei, And The Water Column: Implications For Human Health, Krystal Ann Bakkila
The Movement Of Escherichia Coli And Enterococci Among Beach Sand, Lyngbya Wollei, And The Water Column: Implications For Human Health, Krystal Ann Bakkila
Wayne State University Theses
Occurrence of the filamentous cyanobacteria Lyngbya wollei has become an increasing concern in the Great Lakes region. Prior to the early 1900's, L. wollei had been occasionally documented in the Great Lakes region, but in the last decade it has been observed with increasing frequency. In the Great Lakes L. wollei has been proliferating, fragmenting, and accumulating ashore, where it decays forming thick detrital mats harboring potentially harmful bacteria such as Escherichia coli and enterococci. While the filamentous green algae species Cladophora glomerata has been well studied in this region, very little research has been done on the cyanobacteria L. …
Iron-Regulated Cyanobacterial Predominance And Siderophore Production In Oligotrophic Freshwater Lakes, Ryan J. Sorichetti
Iron-Regulated Cyanobacterial Predominance And Siderophore Production In Oligotrophic Freshwater Lakes, Ryan J. Sorichetti
Electronic Thesis and Dissertation Repository
The frequency and intensity of cyanobacterial blooms (cyanoblooms) is increasing globally. Contrary to existing phosphorus (P) and nitrogen (N) paradigms describing cyanobloom proliferation in eutrophic (nutrient-rich) freshwater lakes, many of the recent cyanobloom reports pertain to oligotrophic (nutrient-poor) freshwater lakes with no prior history of cyanobloom occurrence. There exists a critical research need to re-visit existing conceptual models, identify regulating factors currently unaccounted for and improve our ability to effectively detect and measure cyanobacterial toxins (cyanotoxins) in lakes. Iron (Fe) is required in nearly all pathways of cyanobacterial macronutrient use, though its direct role in regulating cyanobacterial biomass is not …
Novel Lineages Of Prochlorococcus And Synechococcus In The Global Oceans, Sijun Huang, Steven W. Wilhelm, H. Rodger Harvey, Karen Taylor, Nianzhi Jiao, Feng Chen
Novel Lineages Of Prochlorococcus And Synechococcus In The Global Oceans, Sijun Huang, Steven W. Wilhelm, H. Rodger Harvey, Karen Taylor, Nianzhi Jiao, Feng Chen
OES Faculty Publications
Picocyanobacteria represented by Prochlorococcus and Synechococcus have an important role in oceanic carbon fixation and nutrient cycling. In this study, we compared the community composition of picocyanobacteria from diverse marine ecosystems ranging from estuary to open oceans, tropical to polar oceans and surface to deep water, based on the sequences of 16S-23S rRNA internal transcribed spacer (ITS). A total of 1339 ITS sequences recovered from 20 samples unveiled diverse and several previously unknown clades of Prochlorococcus and Synechococcus. Six high-light (HL)-adapted Prochlorococcus clades were identified, among which clade HLVI had not been described previously. Prochlorococcus clades HLIII, HLIV and …
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 …