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Ammonium Chemotaxis In Chlamydomonas Reinhardtii, Gabela Nelson

LSU Doctoral Dissertations

Analysis of ammonium chemotaxis in Chlamydomonas reinhardtii is largely hindered, compared to that of phototaxis, despite equal importance on flagellated microalgal physiology. A major contribution of this shortfall is the lack of proper assay method. We developed a simple Petri dish assay method in which light is homogenously exposed while patterns of the cellular migration are tracked with a function of time. Using the method, new findings were revealed. First, this research presented that a strain lacking the eyespot organelle required for light gradient-sensing exhibits similar chemotactic behavior compared to a wild-type strain, suggesting Chlamydomonas sense an ammonium gradient not …

Seasonal Starch Allocation In Starry Stonewort (Nitellopsis Obtusa) Harvested From Lake Koronis, Mn, And Development Of Non-Chemical Management Recommendations, Alyssa M. Haram

All Graduate Theses, Dissertations, and Other Capstone Projects

Starry stonewort (Nitellopsis obtusa) (Desvaux in Loiseleur) J. Groves is an invasive macro alga that can take over entire water columns and outcompete native species. Previous research has quantified seasonal life history and phenology but there is no research quantifying carbohydrate allocation which was the aim for Chapter II. Management efforts to control Nitellopsis obtusa have been limited to stressing the thalli and have not been able to directly target the reproductive bulbils on larger scales. Smaller scale efforts such as the use of hand pulling can be used but hand pulling is not realistic for larger infestations. Chapter III …

Exploring Secondary Metabolite Profiles Of Sloth Algae, Valerie Quach, Paige Smith

Honors Theses

In this experiment, we investigated the composition of the secondary metabolites in sloth algal cultures. Additionally, we investigated the effects of secondary metabolites in sloth algal cultures on insects. The three outlets of investigation include insect avoidance tests, sending samples to the Natural Center for Natural Products Research, and analyzing sequencing data with AntiSMASH to identify secondary metabolite biosynthetic gene clusters. While our data from the Drosophila fly tests were inconclusive, we found that our samples contain many different gene clusters for terpenes, NRPS, PKS, RiPPs, which are volatile compounds with a wide array of biosynthetic functions. This research can …

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 …

Landsat Collections Reveal Long-Term Algal Bloom Hot Spots Of Utah Lake, Rachel Shanae Tate

Theses and Dissertations

Harmful algal blooms (HABs) and nuisance algal blooms (NABs) are a worldwide phenomenon with implications for human health and safety. HABs occur when algae or bacteria grow in high enough densities to harm animals and humans. A primary component of harmful algal blooms is cyanobacteria, which are aquatic, photosynthesizing microorganisms that produce toxins at high concentrations. Cyanobacterial biomass has increased worldwide in recent decades, raising concern about the future of fresh- and marine-water systems in a changing climate. Understanding the patterns and conditions of past algal blooms can provide useful insights for managing future blooms. Remote sensing can enhance our …

Screening Of Crude Microalgal Extracts For Antimicrobial Activity, Patrick Matulich

Theses & Dissertations

Microbial biofilm associated infections are a significant threat to patients with medical devices and are partially responsible for the increased resistance seen in nosocomial infections. The biofilm chemical and physical properties restrict access of chemotherapeutic agents. Therefore, there is a need to enhance the antimicrobial effects of current chemotherapeutic agents. Microalgae live in competitive environments that include film-forming, opportunistic pathogens S. maltophilia and C. albicans. Extracts from 5 diverse species of microalgae were screened for antimicrobial enhancing effects against established biofilms with two different extraction solvents, 3:1 hexanes and isopropyl (HIPA) and 2-methyltetrahydrofuran (2-MTHF).

Three species, B. braunii, …

Distribution And Population Structure Of The Invasive Nitellopsis Obtusa (Desv. In Loisel.) J. Groves And Native Species Of Characeae In The Northeast U.S.A., Robin Sleith

Dissertations, Theses, and Capstone Projects

Freshwater ecosystems are some of the most biologically diverse environments on Earth. Billions of humans rely on functioning freshwater ecosystems for drinking water and many other services. These ecosystems are increasingly threatened by human impacts including nutrient pollution, invasive species, and climate change. Here I contribute four research chapters that investigate freshwater diversity and ecosystem threats using the Characeae, a family of freshwater green macroalgae, as a study system. Characeae are a diverse and ancient group with more than 500 extant species and a fossil history spanning at least 250 million years. These algae are macrophytes in freshwater ecosystems, and …

Biological Soil Crusts In A Northeastern Pine Barren: Composition And Ecological Effects, Jessica Gilbert

Honors Theses

Biological soil crusts (BSCs), otherwise known as cryptogamic soil crusts, biocrusts, or cyanobacterial crusts, are soil aggregations hosting diverse biotic communities. They are composed of cyanobacteria and algae, and generally have a covering of moss and/or lichen. BSCs are typically found in arid to semi-arid regions throughout the world, and are integral soil stabilizers, moisture retainers, and nitrogen fixers in these communities. Along with these factors, BSCs are able to impact germination and establishment of plants, either as an accompanying influence, or direct result of those listed above. BSCs have yet to be formally described in the inland northeastern United …

Production And Harvest Of Microalgae In Wastewater Raceways With Resource Recycling, Alexander Colin Roberts

Master's Theses

Microalgae can be grown on municipal wastewater media to both treat the wastewater and produce feedstock for algae biofuel production. However the reliability of treatment must be demonstrated, as well as high areal algae productivity on recycled wastewater media and efficient sedimentation harvesting. This processes was studied at pilot scale in the present research.

A pilot facility was operated with nine CO₂-supplemented raceway ponds, each with a 33-m² surface area and a 0.3-m depth, continuously from March 6, 2013 through September 24, 2014. The ponds were operated as three sets of triplicates with two sets continuously fed …

Inferring Plastid Metabolic Pathways Within The Nonphotosynthetic Free-Living Green Algal Genus Polytomella, Sara Asmail

Electronic Thesis and Dissertation Repository

The advent of photosynthesis facilitated the evolution of aerobic life on Earth. However, species such as Prototheca wickerhamii and Plasmodium falciparum, among many others, have lost photosynthesis and opted for a free-living/parasitic lifestyle. Despite this loss, these species have retained the plastid for its metabolic pathways, without which they would die. Polytomella is a nonphotosynthetic free-living alga, closely related to the photosynthetic model organism Chlamydomonas reinhardtii, and has been shown to lack a plastid genome. I set out to determine Polytomella plastid metabolic pathways using bioinformatics to look for mRNA and DNA homologous sequences matching pathway enzymes in model organisms. …

Size-Fractionated Relationships Between Phytoplankton Production And Biomass, Luke Auman Bassett

Senior Theses

Phytoplankton are the autotrophic foundation of almost all marine ecosystems.

The flow of energy through an ecosystem is largely dependent how productivity moves through organisms of various sizes. For this reason, numerous studies have set out to quantify the respective contributions of these size-fractions to biomass and rates of primary production. This is done through field measurements of production or through mathematic models that infer production contributions from the easier field measured contributions to biomass. However, the accuracy of this method has been called into question. Can contributions to biomass really be used to accurately interpret contributions to production?

The …

Studying The Effects Of Theraflu On The Growth Of Selenastrum Capricornutum, Hannah Gray Boren

Honors Theses

Algae contribute to self-purification of streams and rivers and are necessary as food for fish and as components of aquatic food webs (1). However, too much or too little algae may create or be indicative of a problem. If nutrients are present in large amounts, algae growth may become excessive, resulting in algal “blooms.” These algal blooms can change the chemistry of the water, making it toxic to other aquatic occupants, including fish, birds, animals, and other plants (1). On the other hand, if nutrients in the water are limiting or are exhausted, algae growth is inhibited, which results in …

The Characterization Of Algae Grown On Nutrient Removal Systems And Evaluation Of Potential Uses For The Resulting Biomass, Kristin Hampel

Dissertations

Eutrophication resulting from excess nutrient loads is a major environmental issue that affects surface water quality and causes surplus primary production, thereby reducing dissolved oxygen concentrations. A method for managing nutrients in surface waters involves absorption of excess nutrients by deliberately cultivating benthic algal turf biomass, then harvesting it for a variety of uses, including biofuels, soil amendments, or feed supplements, thus coupling nutrient removal to additional economic drivers.

The goals of this work are to (1) evaluate the composition of algal biomass grown to remove surface water nutrients, (2) compare biomass grown at different geographic locations and in dissimilar …

Studies On Nitrogen And Silicon Deficiency In Microalgal Lipid Production, Curtis Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microalgae are single celled plants that inhabit aquatic and terrestrial environments across the planet. Many species are oleaginous, which means they are capable of producing oils, similar to many higher plants we are familiar with like canola, safflower and coconut. Different from higher plants, however, algae have simple structures that allow them to grow at very high rates. Due to these characteristics—oil production and rapid growth rates—algae are considered a promising future source of oil. Algal oils could be useful for production of food for people, feed for animals, biodiesel, detergents, and many other applications.

Algae have not been heavily …

Applicability Of Pigment Compounds For Reducing Light Stress In Bentgrass, Gregory Keith Bartley

Masters Theses

Chlorinated copper phthalocyanine (Signature) and pulverized cells of Chlorella vulgaris (Chlorella) were evaluated in a controlled environment for their ability to act as photoprotectants under supraoptimal levels of ultraviolet (UV) and photosynthetically active radiation (PAR) when applied to plant leaves. Plant pigment changes were documented using High Performance Liquid Chromatography following 1 week of exposure to supraoptimal light in two separate experiments incorporating UV (106.6 μmol m-2 s-1) and PAR (760.6 μmol m-2 s-1) over a 12h photoperiod. Supraoptimal levels of UV and PAR light were found to cause significant reductions in Agrostis palustris chlorophyll and carotenoid leaf pigment levels. …

Genetic Engineering Of Dunaliella: Potential For Improved Biofuel Production, Alison Wirshing

Honors Theses and Capstones

Biodiesel produced from algal lipids is a promising source of renewable energy. Reasons for using algae, as opposed to vascular plants, are numerous. Oleaginous algae do not require fertile land or fresh water to grow, and therefore do not compete with food crop resources. Algae have short generation times and higher growth rates than larger vascular plants allowing for synthesis and accumulation of large quantities of neutral lipids, about 20-50% of the dry cell weight, in a short period of time. The efficiency of biodiesel production from oleaginous algae could be improved by using transgenic (genetically engineered) algae. The goal …

Algal Response To A Thermal Effluent : Study Of A Power Station On The Provo River, Utah, Usa, Lorin E. Squires

Theses and Dissertations

The effect of a thermal effluent on the attached algae of the Provo River, Utah, USA, was studied from 1975 to 1977. Data for macroscopic and microscopic algae were collected and analyzed. Diatoms, Cladophora glomerata, and Hydrurus foetidus dominated the flora. The thermal effluent significantly affected the algal flora in a section of river 100 to 135 meters long immediately below the discharge point. Cladophora growth was increased and Hydrurus was absent in this area. In addition, diatom production was often higher and diversity lower than in the rest of the river. Community structure was unique from all other adjacent …

Ethionine-Resistant Mutants Of The Filamentous Blue-Green Alga Plectonema Boryanum /|Cby Wayne M. Hentsche, Wayne M. Hentschel

Theses and Dissertations

Ethionine-resistant mutans of Plectonema boryanum have been isolated and partially characterized. The mutant strains exhibit at least 100-fold increase in resistance to L-ethionine. The nature of the change which confers ethionine resistance is not known, but appears to result from the inability of the resistant strains to incorporate ethionine into acid-precipitable material. Initially, ethionine has no effect on the growth rate of the wild-type or the resistant strains, but several hours of exposure to the analog at a concentration greater than 0.5 μg/ml causes a marked inhibition of growth and bleaching in the wild-type cells. The onset of bleaching precedes …

Environmental Interaction In Summer Algal Communities Of Utah Lake, Mark C. Whiting

Theses and Dissertations

Utah Lake is a shallow eutrophic lake located in central Utah. It is characterized by high nutrient and silt loads and by large algal blooms in late summer and early fall. Phytoplankton samples and environmental data were taken from June through August 1974. Phytoplankton species were identified and then quantified in a Palmer counting cell. Environmental continuum theory was employed to describe algal succession and regression analysis was used to discover interactions between algal communities and the environment. Phytoplankton communities in June were characterized by high species diversity. As the lake environment became stressed in late summer due to higher …

Azide Sensitivity In Species Of Chlamydomonas And Carteria, Kim Michael Kobriger

Masters Theses

No abstract provided.

Inorganic Mercury Uptake And Mercury Tolerance Demonstrated By Several Species Of Algae, Daniel S. Filip

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The inhibition by low concentrations of inorganic mercury has been established for several species of freshwater algae, and a method has been developed to determine mercury levels in algal cells, having good precision at levels as low as one hundred parts per billion.

Rapid sorption of inorganic mercury by glassware was minimized by using heavy algal cultures and short term incubations. The rates and extent of mercury uptake by three species of freshwater green algae were delineated under laboratory conditions. Replicate mercury containing cultures yielded slightly different mercury concentrations upon analysis due to analytical errors and glass sorption. Therefore, percent …

The Effect Of Antibiotics On Thermophilic Blue-Green Algae, Erleen Blanche Christenson

Dissertations and Theses

The nature of the action of penicillin on the cell walls of bacteria is reviewed. The composition of bacterial cell walls is compared to cell walls of blue-green algae.

The test organisms used were thermophilic: Anacystis nidulans grew optimally at 35⁰C, whereas Synechococcus lividus grew best at 45⁰ C. Growth was recorded by reading optical densities.

Cells of these two thermophilic blue-green algae were treated with varying dosages of penicillin and streptomycin. Penicillin inhibited growth of Anacystis nidulans and Synechococcus lividus in concentrations of 3.0 µg/ml and 0.03 µg/ml respectively. However, when 0.3 µg/ml of penicillin was added to Anacystis …