Biochemistry, Biophysics, and Structural Biology Commons^™

Microcystin Aids In Cold Temperature Acclimation: Differences Between A Toxic Microcystis Wildtype And Non-Toxic Mutant, Gwendolyn F. Stark, Robbie M. Martin, Laura E. Smith, Bofan Wei, Ferdi L. Hellweger, George S. Bullerjahn, R. Michael L. Mckay, Gregory L. Boyer, Steven W. Wilhelm

Great Lakes Institute for Environmental Research Publications

For Microcystis aeruginosa PCC 7806, temperature decreases from 26 °C to 19 °C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, reactive oxygen species damage, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19 °C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for …

Damped Oscillating Phosphoryl Transfer Reaction In The Cyanobacterial Circadian Clock, Hye In Jang, Pyonghwa Kim, Yongick Kim

Chemistry Faculty Research

Most organisms have circadian clocks to ensure the metabolic cycle to resonate with the rhythmic environmental changes without “damping,” or losing robustness. Cyanobacteria is the oldest and simplest form of life that is known to harbor this biological intricacy. Its KaiABC-based central oscillator proteins can be reconstituted inside a test tube, and the post-translational modification cycle occurs with 24 h periodicity. KaiC’s two major phosphorylation sites, Ser-431 and Thr-432, become phosphorylated and dephosphorylated by interacting with KaiA and KaiB, respectively. Here, we mutate Thr-432 into Ser to find the oscillatory phosphoryl transfer reaction damps. Previously, this mutant KaiC was reported …

Spatio-Temporal Connectivity Of The Aquatic Microbiome Associated With Cyanobacterial Blooms Along A Great Lake Riverine-Lacustrine Continuum, Sophie Crevecoeur, Thomas A. Edge, Linet Cynthia Watson, Susan B. Watson, Charles W. Greer, Jan J.H. Ciborowski, Ngan Diep, Alice Dove, Kenneth G. Drouillard, Thijs Frenken, Robert Michael Mckay, Arthur Zastepa, Jérôme Comte

Great Lakes Institute for Environmental Research Publications

Lake Erie is subject to recurring events of cyanobacterial harmful algal blooms (cHABs), but measures of nutrients and total phytoplankton biomass seem to be poor predictors of cHABs when taken individually. A more integrated approach at the watershed scale may improve our understanding of the conditions that lead to bloom formation, such as assessing the physico-chemical and biological factors that influence the lake microbial community, as well as identifying the linkages between Lake Erie and the surrounding watershed. Within the scope of the Government of Canada’s Genomics Research and Development Initiative (GRDI) Ecobiomics project, we used high-throughput sequencing of the …

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 …

Structure Of A Monomeric Photosystem Ii Core Complex From A Cyanobacterium Acclimated To Far-Red Light Reveals The Functions Of Chlorophylls D And F, Christopher J. Gisriel, Gaozhong Shen, Ming-Yang Ho, Vasily Kurashov, David A. Flesher, Jimin Wang, William H. Armstrong, John H. Golbeck, Marilyn R. Gunner, David J. Vinyard, Richard J. Debus, Gary W. Brudvig, Donald A. Bryant

Publications and Research

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700–800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the “red limit” for light required to drive photochemical …

Environmental Studies Of Cyanobacterial Harmful Algal Blooms Should Include Interactions With The Dynamic Microbiome, Helena L. Pound, Robbie M. Martin, Cody S. Sheik, Morgan M. Steffen, Silvia E. Newell, Gregory J. Dick, R. Michael L. Mckay, George S. Bullerjahn, Steven W. Wilhelm

Great Lakes Institute for Environmental Research Publications

No abstract provided.

Environmental Factors Affecting Chytrid (Chytridiomycota) Infection Rates On Planktothrix Agardhii, Katelyn M. Mckindles, Makayla A. Manes, R. Michael Mckay, Timothy W. Davis, George S. Bullerjahn

Great Lakes Institute for Environmental Research Publications

Planktothrix agardhii dominates the cyanobacterial harmful algal bloom biomass in Sandusky Bay, Lake Erie (USA) from May until September. This filamentous cyanobacterium known parasites including the chytrid fungal species Rhizophydium sp. C02, which was previously isolated from this region. The purpose of our work has been to establish how parasitic interactions affect Planktothrix population dynamics during a bloom event. Samples analyzed from the 2015 to 2019 bloom seasons using quantitative PCR investigate the spatial and temporal prevalence of chytrid infections. Abiotic factors examined in lab include manipulating temperature (17-31°C), conductivity (0.226-1.225 mS/cm) and turbulence. Planktothrix-specific chytrids are present throughout the …

Improvement Of Biochar Through Ozonization And Biosafety Of Genetically Engineered Cyanobacteria, Oumar Sacko

Chemistry & Biochemistry Theses & Dissertations

Through the innovative technique of biochar post-production surface oxygenation by ozonization, we were able to improve certain properties of biochar. In project one, the incubation of an insoluble phosphate rock material (hydroxyapatite) with the wet ozonized pine 400 biochar and its filtrate resulted in a solubilization of 80 times more phosphate from hydroxyapatite (569.0 mg/L ± 6.4) compared to the pure water-hydroxyapatite control (7.2 mg/L ± 0.3). The ozonized biochar may provide a new possible way to unlock the phosphorus from insoluble phosphate mineral phases. The cation exchange capacity (CEC) is a key property of biochar when used as a …

Isolation And Characterization Of Rhizophydiales (Chytridiomycota), Obligate Parasites Of Planktothrix Agardhii In A Laurentian Great Lakes Embayment, Katelyn M. Mckindles, Alejandro N. Jorge, R. Michael Mckay, Timothy W. Davis, George S. Bullerjahna

Great Lakes Institute for Environmental Research Publications

Planktothrix agardhii dominates the cyanobacterial harmful algal bloom community in Sandusky Bay, Lake Erie (USA), from May through September. This filamentous cyanobacterium is host to a known obligate parasite, the chytrid Rhizophydium sp. During the 2018 bloom season, by utilizing dilution and single-filament isolation techniques, 7 chytrid and 12 P. agardhii strains were isolated from Sandusky Bay. These 7 chytrids and a selection of P. agardhii hosts were then characterized with respect to infection rates. Infections by the isolated chytrids were specific to Planktothrix planktonic species and were not found on other filamentous cyanobacterial taxa present in the bay (Aphanizomenon …

Molecular Mechanism Of Cyanobacteria Circadian Clock Oscillator And Effect Of Co Factors On Its Oscillation, Manpreet Kaur

Dissertations

The circadian rhythms arise as an adaptation to the environmental 24-hour day and night cycle due to Earth's rotation. These rhythms prepare organisms to align their internal biological activities and day to day behavior or events with the environmental change of the 24-hour day and night cycle. Circadian rhythms are found widely in all living kingdoms of life on Earth. Cyanobacteria are photosynthetic prokaryotes which first used to study these circadian rhythms. Among cyanobacterial species, Synechococcus elongatus PCC 7942 (henceforth, S. Elongatus) is the simplest organism with a durable and sturdy circadian clock and is study as a model organism. …

Engineering Natural Competence Into The Fast-Growing Cyanobacterium Synechococcus Elongatus Utex 2973, Kristen Elizabeth Wendt

Arts & Sciences Electronic Theses and Dissertations

Synechococcus elongatus UTEX 2973 is the fastest growing cyanobacterium discovered to date. Using water, carbon dioxide, and light alone, this organism can double in 1.5 hours under optimal conditions. The accelerated doubling exhibited by Synechococcus 2973 makes it a prime candidate to serve as a model photoautotrophic system. However, Synechococcus 2973 lacks one highly desirable feature: it cannot undergo natural transformation. This thesis seeks to engineer this capacity into this fast-growing system in order to create an organism that is both fast growing and naturally competent. Synechococcus 2973 is a unique platform because it is >99% genetically identical to another …

Bloom Announcement: An Early Autumn Cyanobacterial Bloom Co-Dominated By Aphanizomenon Flos-Aquae And Planktothrix Agardhii In An Agriculturally-Influenced Great Lakes Tributary (Thames River, Ontario, Canada), R. Michael Mckay, Thijs Frenken, Ngan Diep, William R. Cody, Sophie Crevecoeur, Alice Dove, Kenneth G. Drouillard, Xavier Ortiz, Jason Wintermute, Arthur Zastepa

Great Lakes Institute for Environmental Research Publications

No abstract provided.

The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R. Michael L. Mckay

Great Lakes Institute for Environmental Research Publications

Blooms of the toxin-producing cyanobacterium Microcystis 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. Microcystis 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 …

Genetic Study Of Alkane Production And Oxic Nitrogen Fixation In Anabaena Sp. Pcc 7120, Jaimie L. Gibbons

Electronic Theses and Dissertations

Anabaena sp. PCC 7120 is a filamentous, nitrogen-fixing cyanobacterium that uses spatial separation to perform photosynthesis and nitrogen fixation simultaneously. Under fixed nitrogen limiting conditions, Anabaena 7120 forms specialized cells, called heterocysts, to fix nitrogen. In this research, I sought to add to the knowledge surrounding the process of heterocystous nitrogen fixation in Anabaena 7120. Cyanobacteria universally produce alkanes, which have been suggested to play a role in helping the organism adapt to abiotic stress, such as diazotrophic conditions. In my first study, I sought to identify the genes required for production of the hydrocarbon heptadecane (C17H36). Through using a …

Insight Into The Molecular Mechanisms For Microcystin Biodegradation In Lake Erie And Lake Taihu, Lauren E. Krausfeldt, Morgan M. Steffen, Robert M. Mckay, George S. Bullerjahn, Gregory L. Boyer, Steven W. Wilhelm

Great Lakes Institute for Environmental Research Publications

Microcystins are potent hepatotoxins that are frequently detected in fresh water lakes plagued by toxic cyanobacteria. Microbial biodegradation has been referred to as the most important avenue for removal of microcystin from aquatic environments. The biochemical pathway most commonly associated with the degradation of microcystin is encoded by the mlrABCD (mlr) cassette. The ecological significance of this pathway remains unclear as no studies have examined the expression of these genes in natural environments. Six metatranscriptomes were generated from microcystin-producing Microcystis blooms and analyzed to assess the activity of this pathway in environmental samples. Seventy-eight samples were collected from Lake Erie, …

Understanding Excitation Energy Quenching In Isia, Hui-Yuan Steven Chen

McKelvey School of Engineering Theses & Dissertations

Cyanobacteria are photoautotrophic organisms that contribute a significant amount of global primary productivity. They are found in freshwater, marine and even some extremely severe environments. Among those environments, iron deficiency is one of the most common stress conditions in cyanobacterial habitats. To survive, cyanobacteria have evolved and developed several strategies to alleviate the damage caused by iron deficiency.

Iron stress-inducible protein (IsiA) is a chlorophyll-binding membrane protein found in cyanobacteria grown in iron-deficient conditions. During the past decades, considerable effort has been put on understanding how IsiA functions to help cyanobacteria survive iron deficiency. It has been reported that IsiA …

Diverse Far-Red Light Utilization Strategies In Cyanobacteria And Algae, Benjamin Martin Wolf

Arts & Sciences Electronic Theses and Dissertations

In their natural environments, photosynthetic organisms are often exposed to widely varied light environments. Species adapted to shade light, often found growing in lower layers of photosynthetic biofilms, must survive on filtered light alone. Filtered light is highly enriched in far-red wavelengths, which are normally unavailable for photosynthetic energy production in most oxygenic phototrophs. To overcome light limitations in filtered light environments, some species of algae and cyanobacteria utilize specialized photosynthetic pigments and antenna systems to harvest these far-red wavelengths. By sampling the natural environment and using custom-built far-red light growth chambers, I have isolated several species of oxygenic phototrophs …

Metabolic Engineering Of Cyanobacteria For Production Of Chemicals, Po-Cheng Lin

McKelvey School of Engineering Theses & Dissertations

Concerns over the impact of climate change caused by CO2 emission have driven the research and development of renewable energies. Microbial production of chemicals is being viewed as a feasible approach to reduce the use of fossil fuels and minimize the impact of climate change. With recent advances in synthetic biology, microorganisms can be engineered to synthesize petroleum-based chemicals and plant-derived compounds. Cyanobacteria are photosynthetic prokaryotes that use only sunlight, CO2, and trace minerals for growth. Compared to other microbial hosts, cyanobacteria are attractive platforms for sustainable bioproduction, because they can directly convert CO2 into products. However, the major challenge …

Metabolic Engineering Of Cyanobacteria For Production Of Chemicals, Po-Cheng Lin

McKelvey School of Engineering Theses & Dissertations

Concerns over the impact of climate change caused by CO2 emission have driven the research and development of renewable energies. Microbial production of chemicals is being viewed as a feasible approach to reduce the use of fossil fuels and minimize the impact of climate change. With recent advances in synthetic biology, microorganisms can be engineered to synthesize petroleum-based chemicals and plant-derived compounds. Cyanobacteria are photosynthetic prokaryotes that use only sunlight, CO2, and trace minerals for growth. Compared to other microbial hosts, cyanobacteria are attractive platforms for sustainable bioproduction, because they can directly convert CO2 into products. However, the major challenge …

Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant

Chemistry and Biochemistry Publications

(S)-2,4-Diaminobutanoic acid (DABA) is a noncanonical amino acid often co-produced by cyanobacteria along with β-N-methylamino-l-alanine (BMAA) in algal blooms. Although BMAA is a well-established neurotoxin, the toxicity of DABA remains unclear. As part of our development of biocompatible materials, we wish to make use of DABA as both a building block and as the end-product of enzymatically-induced depolymerization; however, if it is toxic at very low concentrations, this would not be possible. We examined the toxicity of DABA using both in vivo embryonic and adult zebrafish models. At higher sub-lethal concentrations (700 µM), the fish demonstrated early …

Ammonium Recycling Supports Toxic Planktothrix Blooms In Sandusky Bay, Lake Erie: Evidence From Stable Isotope And Metatranscriptome Data, Justyna J. Hampel, Mark J. Mccarthy, Michelle Neudeck, George S. Bullerjahn, Robert Michael L. Mckay, Silvia E. Newell

Great Lakes Institute for Environmental Research Publications

Sandusky Bay, Lake Erie, receives high nutrient loadings (nitrogen and phosphorus) from the Sandusky River, which drains an agricultural watershed. Eutrophication and cyanobacterial harmful algal blooms (cyanoHABs) persist throughout summer. Planktothrix agardhii is the dominant bloom-forming species and the main producer of microcystins in Sandusky Bay. Non-N2 fixing cyanobacteria, such as Planktothrix and Microcystis, thrive on chemically reduced forms of nitrogen, such as ammonium (NH4+) and urea. Ammonium regeneration and potential uptake rates and total microbial community demand for NH4+ were quantified in Sandusky Bay. Potential NH4+ uptake rates in the light increased from June to August at all stations. …

Water Temperature And Harmful Algal Bloom Rate, Geoff Bright, Greg Michalski, Benjamin P. Wilkins

The Summer Undergraduate Research Fellowship (SURF) Symposium

Harmful algal blooms, made up of cyanobacteria, is an increasing problem in Midwestern lakes. Nitrogen and phosphorus fertilizers used in crops such as corn and soybeans run off into streams and eventually lakes. Nitrogen and phosphorus in the form of nitrate and phosphate respectively is then used by cyanobacteria as a food source, allowing them to bloom at an alarming rate. Massive bloom events can be hazardous to both human health and the natural environment because of the release of neurotoxins, hepatotoxins and others into the air and drinking water. We set out to find if different water temperature can …

Proteogenomic Study Of Nitrogen-Fixing Cyanobacterium Anabaena Cylindrica, Yeyan Qiu

Electronic Theses and Dissertations

Cyanobacteria are gram-negative photosynthetic bacteria. In some filamentous cyanobacteria such as Anabaena cylindrica, every 10^th to 20^th vegetative cells can differentiate into nitrogen fixing heterocysts. Heterocyst can induce the neighboring cells developing into spore-like akinetes. The specialized cell functions and resourceful networks have contributed to the prosperity of cyanobacteria for over 2 billion years, but the genetic mechanisms for multi-cellular differentiation are barely known, especially for akinete formation. The heterocysts, akinetes and vegetative cells of Anabaena cylindrica were isolated for proteomic study. This study identified a total of 1395 proteins, including 664 proteins from akinetes, 751 proteins from …

The Synthetic Biology Of N2-Fixing Cyanobacteria For Photosynthetic Terpenoid Production, Charles T. Halfmann

Electronic Theses and Dissertations

In the last few decades, concerns over global climate change, energy security, and environmental pollution have been rising. To overcome these challenges, the concept of “-n^th generation” biofuels has emerged as a strategy to convert solar radiation into fuels and bulk industrial chemicals for societal use, while decreasing our consumption of nonrenewable energy sources. Nitrogen-fixing cyanobacteria hold a distinct advantage in biofuel production over plants, given their ability to convert sunlight, air (CO₂ and N₂), and mineralized water to energy-dense carbon molecules, as well as fix atmospheric nitrogen gas into ammonia for metabolism. Engineered cyanobacteria with …

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 …

Global Solutions To Regional Problems: Collecting Global Expertise To Address The Problem Of Harmful Cyanobacterial Blooms. A Lake Erie Case Study, George S. Bullerjahn, Robert M. Mckay, Timothy W. Davis, David B. Baker, Gregory L. Boyer, Lesley V. D'Anglada, Gregory J. Doucette, Jeff C. Ho, Elena G. Irwin, Catherine L. Kling, Raphael M. Kudela, Rainer Kurmayer, Anna M. Michalak, Joseph D. Ortiz, Timothy G. Otten, Hans W. Paerl, Boqiang Qin, Brent L. Sohngen

Great Lakes Institute for Environmental Research Publications

In early August 2014, the municipality of Toledo, OH (USA) issued a ‘do not drink’ advisory on their water supply directly affecting over 400,000 residential customers and hundreds of businesses (Wilson, 2014). This order was attributable to levels of microcystin, a potent liver toxin, which rose to 2.5 μg L−1 in finished drinking water. The Toledo crisis afforded an opportunity to bring together scientists from around the world to share ideas regarding factors that contribute to bloom formation and toxigenicity, bloom and toxin detection as well as prevention and remediation of bloom events. These discussions took place at an NSF- …

The Evolution Of Thermotolerance A Characterization Of A Directionally Evolved Cyanobacterium, Nathen Emil Bopp

Masters Theses

Chaperone proteins are essential components in the maintenance and turnover of the proteome. Many chaperones play integral functions in the folding and unfolding of cellular substrates under many conditions, including heat stress. Most chaperones can be characterized into two categories; the typical ATP dependent chaperones and the ATP independent chaperones. One ATP independent chaperone class it the Small Heat Shock Proteins (sHSPs), which as molecular life vests and are thought to protect misfolding proteins from irreversible aggregation. One such organism, the cyanobacterium Synechocystis sp. PCC 6803, is an excellent model for the study and understanding of these proteins and their …

Development Of A Maldi-Tof-Ms Method For The Analysis Of Cyanobacterial Neurotoxin Β-N-Methylamino-L-Alanine (Bmaa) In Search Of Bmaa Incorporation In Biological Samples, Laura M. Conklin

FIU Electronic Theses and Dissertations

Beta-N-methylamino-L-alanine (BMAA) is a non-protein amino acid produced by many cyanobacteria, and thought to induce neurotoxic effects through excitotoxicity, contributing to neurodegenerative diseases such as Amyotrophic Lateral Sclerosis/Parkinsonism-dementia complex (ALS-PDC) and Alzheimer’s. The ubiquitous nature of cyanobacteria, and evidence of biomagnification through our food web, creates a dire need for the development of an analytical platform that will provide accurate identification and quantification of BMAA amounts in our ecosystem and potential food supply. The present study evaluated the ability of a MALDI-ToF-MS method to detect and quantify BMAA in a variety of biological matrices. Through validation procedures, it …

Exploring The Effect Of Climate Change On Biological Systems, Nardos Sori

Chemistry & Biochemistry Theses & Dissertations

The present and potential future effect of global warming on the ecosystem has brought climate change to the forefront of scientific inquiry and discussion. For our investigation, we selected two organisms, one from cyanobacteria and one from a cereal plant to determine how climate change may impact these biological systems. The study involved understanding the physiological and adaptive responses at both the genetic and protein function levels to counteract environmental stresses. An increase in atmospheric carbon dioxide is a key factor in global climate change and can lead to alterations in ocean chemistry. Cyanobacteria are important, ancient and ubiquitous organisms …

Transcriptomic And Proteomic Dynamics In The Metabolism Of A Diazotrophic Cyanobacterium, Cyanothece Sp. Pcc 7822 During A Diurnal Light-Dark Cycle, Louis Sherman

Louis A Sherman

Background: Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be applied as a biocatalyst for the production of high value compounds. Like other unicellular diazotrophic cyanobacterial species, it has a tightly regulated metabolism synchronized to the light-dark cycle. Utilizing transcriptomic and proteomic methods, we were able to quantify the relationships between transcription and translation underlying central and secondary metabolism in response to nitrogen free, 12 hour light and 12 hour dark conditions.

Results: By combining mass-spectrometry based proteomics and RNA-sequencing transcriptomics, we quantitatively measured a total of 6766 mRNAs and 1322 proteins at four …