Biology Commons^™

Mimicking Biofilms: Photosynthetic Assessments Of C. Reinhardtii In 3 Physical Forms, John Michael Roesgen

Biology ETDs

Oxygenic photosynthesis supports the majority of life on Earth through the capture of energy from sunlight and the assimilation of CO₂ into basic building blocks of cells. Microalgae are fast growing and account for about half of global photosynthesis. In addition, they can be cultivated and their metabolism can be redirected to generate additional useful products ranging from biofuels to pharmaceuticals. However, the efficiency of metabolite production is severely impacted by the slow diffusion of CO₂ through water and the high energetic costs of harvesting microalgae from liquid cultures. Microalgae grow in open water, but they also form …

The Effects Of Variations In Light And Nutrient Availability On Phytoplankton And Zooplankton, Jake Anthony Swanson

Theses and Dissertations

Aquatic ecosystems experience a wide range of variation in resource availability; two of the resources that are most essential to phytoplankton and zooplankton are light and nutrients. Light can vary in both its color and intensity; these variations can directly impact phytoplankton by altering the amount and color of light available for photosynthesis. Nutrient variability, particularly increases in nutrient levels, also alter phytoplankton communities by favoring the growth of certain taxa such as cyanobacteria.

To understand whether phytoplankton respond differently to changes in light availability I investigated whether the diversification of cryptophytes, phytoplankton with diverse light-capturing pigments, showed evidence of …

Propagation, Physiology And Biomass Of Giant Cane (Arundinaria Gigantea) For Conservation And Restoration, Sanjeev Sharm

MSU Graduate Theses

Giant cane (Arundinaria gigantea) is a native species to 22 states in the U.S. The species and its ecosystem are considered critically endangered, and the species has been reduced to 2% of its original extent. The species has a long cultural and conservation history. Large canebrakes were commonly found in Missouri in bottomland forests, stream and riverbanks, and margins of lakes. My research goals were to: 1) examine methods for propagation success from field to greenhouse to field; 2) examine the physiology of cane at one of the few current canebrakes, for greenhouse propagated plants, and field planted …

Effect Of Temperature On Growth And Gene Expression In The Marine Diatom, Thalassiosira Pseudonana, John M. Foster

USF Tampa Graduate Theses and Dissertations

Diatoms are unicellular, eukaryotic, photosynthetic algae responsible for the production of 20% of our atmospheric oxygen. Diatoms contribute to several important biogeochemical functions. Diatoms contribute to the carbon cycle, sequestering carbon and forming oxygen as a product of photosynthesis. Moreover, by converting abiotic forms of energy such as sunlight into organic compounds (i.e., sugars, starches and lipids), primary producers including diatoms, plants, and phytoplankton feed organisms at higher trophic levels. Consequently, changes in temperature, light intensity, nutrients, salinity and other stress factors that affect primary producers can generate a potentially catastrophic ripple effect at higher trophic levels In this study …

Effects Of Low-Level Artificial Light At Night On Kentucky Bluegrass And Introduced Herbivore, Morgan Crump, Cassandra Brown, Robert J. Griffin-Nolan, Lisa Angeloni, Nathan P. Lemoine, Brett Seymoure

Biological Sciences Faculty Research and Publications

Increasing evidence suggests that artificial light at night (ALAN) can negatively impact organisms. However, most studies examine the impacts of ALAN on a single species or under high levels of artificial light that are infrequent or unrealistic in urban environments. We currently have little information on how low levels of artificial light emanating from urban skyglow affect plants and their interactions with herbivores. We examined how low levels of ALAN affect grass and insects, including growth rate, photosynthesis, and stomatal conductance in grass, and foraging behavior and survival in crickets. We compared growth and leaf-level gas exchange of Kentucky Bluegrass …

Community Dynamics And Function Of Algae And Bacteria During Winter In Central European Great Lakes, George S. Bullerjahn, Robert Michael L. Mckay, Gábor Bernát, Ondřej Prášil, Lajos Vörös, Károly Pálffy, Nóra Tugyi, Boglárka Somogyi

Great Lakes Institute for Environmental Research Publications

Abundant phytoplankton and bacteria were identified by microscopy and high-throughput 16S rRNA tag Illumina sequencing of samples from water- and ice phases collected during winter at two central European Great Lakes, Balaton and Fertő (Neusiedlersee). Bacterial reads at all sites were dominated (>85%) by Bacteroidetes and Proteobacteria. Amongst phototrophs, microscopy and 16S sequencing revealed that both phytoplankton and cyanobacteria were represented, with a median of 1500 cyanobacterial sequence reads amongst 13 samples analyzed. The sequence analysis compared replicate Balaton and Fertő ice and water samples with an outgroup from three Hungarian soda lakes. In particular, both water and ice …

Can Desert Mosses Hide From Climate Change? The Ecophysiological Importance Of Habitat Buffering & Water Relations To A Keystone Biocrust Moss In The Mojave Desert, Theresa Ann Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

Empirical and observational studies suggest a keystone biocrust moss, Syntrichia caninervis, may be sensitive to future climate change in the American Southwest due to its uniquely sensitive water relations that appear particularly challenged during summer hydration-desiccation cycles. However, the potential mitigating roles of habitat buffering, acclimatization, and winter recovery on the vulnerability of this species remain largely unexplored. I investigated potential abiotic and biotic resiliency factors driving summer stress resistance and recovery in S. caninervis along present-day aridity gradients in the Mojave Desert to strengthen the climate change vulnerability assessment for this species common to biocrusts of North America, northern …

Subfunctionalization Of Phytochrome B1/B2 Leads To Differential Auxin And Photosynthetic Responses, Keisha D. Carlson, Sneha Bhogale, Drew Anderson, Alondra Zaragoza-Mendoza, Andreas Madlung

All Faculty Scholarship

Gene duplication and polyploidization are genetic mechanisms that instantly add genetic material to an organism's genome. Subsequent modification of the duplicated material leads to the evolution of neofunctionalization (new genetic functions), subfunctionalization (differential retention of genetic functions), redundancy, or a decay of duplicated genes to pseudogenes. Phytochromes are light receptors that play a large role in plant development. They are encoded by a small gene family that in tomato is comprised of five members: PHYA, PHYB1, PHYB2, PHYE, and PHYF. The most recent gene duplication within this family was in the ancestral PHYB gene. Using transcriptome profiling, co-expression network analysis, …

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 …

Species Composition Influences Soil Nutrient Depletion And Plantphysiology In Prairie Agroenergy Feedstocks, Mark E. Sherrard, Kenneth Elgersma, Jordan M.A. Koos, Catherine M. Kokemuller, Hannah E. Dietz, Alec J. Glidden, Christina M. Carr, Cynthia A. Cambardella

Faculty Publications

High-diversity mixtures of perennial tallgrass prairie vegetation could be useful biomass feed-stocks for marginal farmland in the Midwestern United States. These agroenergy crops can help meet cel-lulosic agrofuel targets while also enhancing other ecosystem services on the landscape. One proposedadvantage of high-diversity prairie biomass feedstocks is that they should become nutrient limited at aslower rate than monoculture feedstocks. In this study, we examine rates of soil nutrient depletion and thephysiology and performance of a focal species (switchgrass,Panicum virgatumL.) in four prairie agroen-ergy feedstocks with different species composition and diversity. The feedstocks in this study were a1-species switchgrass monoculture, a 5-species …

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, …

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 …

Greening Rates And Photosynthetic Development Of Leaves In C3 And C4 Plants, Tayler J. Kriss

Master's Theses

To study chlorophyll development time and overall photosynthetic development in C3 and C4 leaves, seeds were germinated in complete darkness and achlorophyllous leaves were then allowed to develop in lighted conditions. Corn (Zea mays, C4), sorghum (Sorghum bicolor, C4), green bean (Phaseolus vulgaris, C3), broad bean (Vicia faba, C3), and wheat (Triticum aestivum, C3) were investigated for the first ten days of sunlight exposure. Chlorophyll concentration, chlorophyll fluorescence, and CO2 gas exchange measurements were conducted daily on the first leaf that emerged after the embryonic leaves of each plant. The first five days of the experiment, days zero to four …

The Effects Of Seawater Temperature On Photosynthesis In Crustose Coralline Algae, Alexander Carlson

Independent Study Project (ISP) Collection

Crustose Coralline Algae (CCA) are prolific reef builders and primary producers that play a key role in maintaining the structural integrity of coral reef systems (Littler and Littler, 2013). They are also highly important in increasing reef resilience by serving as a substrate for the recruitment and metamorphosis of coral larvae (Chisholm, 2000). Little is known about the way in which increasing seawater temperatures due to climate change might affect metabolic rates like photosynthesis in CCA. Therefore, a study was carried out in November, 2018, in the lab at Lizard Island Research Station to explore the photosynthetic performance of a …

Dehydration Stress Memory: Gene Networks Linked To Physiological Responses During Repeated Stresses Of Zea Mays, Laetitia Virlouvet, Thomas J. Avenson, Qian Du, Chi Zhang, Ning Liu, Michael Fromm, Zoya Avramova, Sabrina E. Russo

School of Biological Sciences: Faculty Publications

Stress memory refers to the observation that an initial, sub-lethal stress alters plants’ responses to subsequent stresses. Previous transcriptome analyses of maize seedlings exposed to a repeated dehydration stress has revealed the existence of transcriptional stress memory in Zea mays. Whether drought-related physiological responses also display memory and how transcriptional memory translates into physiological memory are fundamental questions that are still unanswered. Using a systems-biology approach we investigate whether/how transcription memory responses established in the genome-wide analysis of Z. mays correlate with 14 physiological parameters measured during a repeated exposure of maize seedlings to dehydration stress. Co-expression network analysis revealed …

Phytobiome And Transcriptional Adaptation Of Populus Deltoides To Acute Progressive Drought And Cyclic Drought, Benjamin Garcia, Jessy Labbé, Piet Jones, Piet Jones, Paul Abraham, Ian Hodge, Ian Hodge, Sharlee Climer, Sara Jawdy, Lee Gunter, Gerald Tuskan, Xiaohan Yang, Timothy Tschaplinski, Daniel Jacobson, Daniel Jacobson

Computer Science Faculty Works

Plant drought stress causes systematic changes to photosynthesis, metabolism, growth, and potentially the phytobiome. Additionally, drought affects plants in both a species-specific and water-deficit-driven manner, causing the response to drought to be dependent both on how drought is being experienced and on any adaptation to prior drought exposure. Thus, understanding the effect of drought on plants requires assessing drought response in multiple conditions, such as progressive acute drought and recurrent cyclic drought, and at different levels of severity. In this study, we have utilized RNA sequencing to identify changes to the plant transcriptome and the phytobiome during both acute progressive …

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum

Theses and Dissertations

The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum

Theses and Dissertations

The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …

Application Of Proline To Root Medium Is More Effective For Amelioration Of Photosynthetic Damages As Compared To Foliar Spraying Or Seed Soaking In Maize Seedlings Under Short-Term Drought, Mehmet Demi̇ralay, Cansu Altuntaş, Asi̇ye Sezgi̇n, Rabi̇ye Terzi̇, Asi̇m Kadioğlu

Turkish Journal of Biology

Exogenous proline (PRO) at low concentrations can enhance drought stress tolerance in different application modes such as application to rooting medium, foliar spray, and seed soaking. However, there is no information about which application mode is more effective for increasing the drought tolerance. Comparative effects of 1, 10, and 20 mM PRO applications through three application modes to hydroponically grown seedlings were examined under short-term drought stress in maize seedlings. Effects on leaf water potential, membrane damage, chlorophyll content, proline level, and gas exchange parameters such as net photosynthetic rate (Pn), transpiration rate (E), stomatal conductance (gs), and substomatal CO2 …

The Variation Of Productivity And Its Allocation Along A Tropical Elevation Gradient: A Whole Carbon Budget Perspective, Yadvinder Malhi, Cécile A. J. Girardin, Gregory R. Goldsmith, Christopher E. Doughty, Norma Salinas, Daniel B. Metcalfe, Walter Huaraca Huasco, Javier E. Silva-Espejo, Jhon Del Aguilla-Pasquell, Filio Farfán Amézquita, Luiz E.O.C. Aragão, Rossella Guerrieri, Françoise Yoko Ishida, Nur Bahar, William Farfan-Rios, Oliver L. Phillips, Patrick Meir, Miles Silman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

• Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation.
  
  
• We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 3300 m elevation transect in Peru.
  
  
• Low growth rates at high elevations appear primarily driven by low gross primary productivity (GPP), with little shift in either carbon use efficiency (CUE) or allocation of net primary productivity (NPP) between wood, fine roots and canopy. The lack of trend in …

Use Of Proteomics To Probe Dynamic Changes In Cyanobacteria, Amelia Yen Nguyen

Arts & Sciences Electronic Theses and Dissertations

Cyanobacteria are unicellular photosynthetic microorganisms that capture and convert light energy to chemical energy, which is the precursor for feed, fuel, and food. These oxygenic phototrophs appear blue-green in color due to the blue bilin pigments in their phycobilisomes and green chlorophyll pigments in their photosystems. They also have diverse morphologies, and thrive in terrestrial, marine water, fresh water, as well as extreme environments. Cyanobacteria have developed a number of protective mechanisms and adaptive responses that allow the photosynthetic process to operate optimally under diverse and extreme conditions. Prolonged deprivation of essential nutrients, such as nitrogen and sulfur, commonly found …

Salinity Effects On Expression Of Some Important Genes In Sensitiveand Tolerant Grape Genotypes, Nayer Mohammadkhani, Reza Heidari, Nasser Abbaspour, Fatemeh Rahmani

Turkish Journal of Biology

The effects of NaCl on expression of some genes related to salinity tolerance in grape (Vitis L.) were investigated. According to our screening study on eighteen grape genotypes, H6 and Gharashani (tolerant) and Shirazi and GhezelUzum (sensitive) were selected for molecular analysis. Our tolerant genotypes showed a higher water potential and a lower MDA content compared to other genotypes. Plants were treated with 50 mM NaCl as a critical concentration that is not lethal for grape. The expression profile of VvNHL1 in leaves of all genotypes and in roots of tolerant genotypes was similar to that of VvEDS1; these genes …

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. …

The Effects Of Canopy Structure On Photosynthesis In Sphagnum Mosses, Eric Matthew Ward

Honors Theses

In open habitats, Sphagnum grows with a dense architecture to retain water; mosses adapted to survive in shade persist in looser canopies. It is unknown if there is a physiological advantage of such rough canopies in the shade, but they may have enhanced photosynthesis at low light angles as would occur during spring or fall. It was hypothesized that the rough canopies would have enhanced rates of photosynthesis at lower angles. To test this, a photosynthesis system interfaced with a custom chamber was used to generate light response curves. Preliminary results of the study found no difference in photosynthesis with …

Regulation Of Ribulose 1, 5-Bisphosphate Carboxylase/Oxygenase By Metabolites, Jerome Servaites, Donald Geiger

Donald R. Geiger

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and other enzymes and their common metabolites form a system regulated by feedforward and feedback mechanisms that is directly involved in assimilation of carbon. The interaction of these components in the chloroplast gives rise to properties, which can not be predicted from the study of isolated components alone. Experiments were conducted to explain how the observed pattern of system level regulation is consistent with the individual characteristics of Rubisco measured in vitro. In vitroRubisco is responsive to a wide range of ribulose 1,5-bisphosphate and phosphoglycerate concentrations, similar to those found in leaves under field conditions. Metabolite …

Salicylic Acid Alleviates Cold-Induced Photosynthesis Inhibition Andoxidative Stress In Jasminum Sambac, Han Cai, Mengying He, Kun Ma, Yonggao Huang, Yun Wang

Turkish Journal of Biology

Salicylic acid (SA) is a signal molecule that mediates many biotic and abiotic stress-induced physiological responses in plants. In the current study the protective effects of SA on cold stress-caused oxidative damage and photosynthesis inhibition in jasmine plants (Jasminum sambac) were examined. Jasmine seedlings were pretreated with 100 µM SA for 3 days and then subjected to cold stress (4 °C) for 15 days. The amounts of superoxide radicals (O_2^{-}) and hydrogen peroxide (H_{2}O_{2}) significantly increased in leaves of plants exposed to cold stress and resulted in oxidative damage, indicated by an increase in malondialdehyde accumulation and membrane leakage. The …

Nitrogen Inputs And Losses In Response To Chronic Co2 Exposure In A Subtropical Oak Woodland, B. A. Hungate, B. D. Duval, P. Dijkstra, D. W. Johnson, M. E. Ketterer, Peter Stiling, W. Cheng, J. Millman, A. Hartley, D. B. Stover

Integrative Biology Faculty and Staff Publications

Rising atmospheric CO₂ concentrations may alter the nitrogen (N) content of ecosystems by changing N inputs and N losses, but responses vary in field experiments, possibly because multiple mechanisms are at play. We measured N fixation and N losses in a subtropical oak woodland exposed to 11 years of elevated atmospheric CO₂ concentrations. We also explored the role of herbivory, carbon limitation, and competition for light or nutrients in shaping the response of N fixation to elevated CO₂. Elevated CO₂ did not significantly alter gaseous N losses, but lower recovery and deeper distribution in the …

Comparison Of Photosynthetic Ability In Single And Double Palisade Parenchyma Leaves In Southern California, Vincent Quach, Ryan Sauer, Haley Smith, Christian Wright

Featured Research

Melaleuca quinquenervia is a myrtle (family Myrtaceae) with a propensity for invasiveness. The leaves feature an isobilateral orientation: vertically aligned with a layer of palisade parenchyma on both the adaxial and abaxial sides. Quercus agrifolia (Fagaceae) is a native evergreen with one layer of palisade parenchyma. Due to this structural difference, it was hypothesized that Melaleuca would have a higher rate of photosynthesis (Pn) and less reflectance (NDVI) of green light than Quercus. These two variables were compared using an unpaired t-test, yielding p-values of 0.1366 for NDVI and 0.04428 for photosynthetic rate. No significant difference was found between the …

Photosynthetic Characteristics Of Red And Green Leaves In Growing Seedlings Of Jatropha Curcas, Munna Singh, Sanjay Ranjan, Krishan Kumar Verma, Uday Vashudav Pathre, Pramod Arvind Shirke

Turkish Journal of Biology

The use of Jatropha (Jatropha curcas L.) as a source of biofuel is documented. The physiological characteristics and growth studies of Jatropha have received less attention. In the present study, we measured leaf gas exchange with an infrared gas analyzer for red (immature) and green (mature) leaves of Jatropha curcas in response to various environmental conditions including photosynthetic photon flux density (PPFD), vapor pressure difference, and temperature. The seedlings were grown in pots for 45 days in a natural environment. Jatropha is a C_3 plant based on its leaf-gas exchange characteristics. The optimal light-saturated photosynthetic CO_2 assimilation, leaf conductance, and …

Measuring Photosynthesis To Evaluate Photoprotection By Anthocyanins In Malosma Laurina, Jorge Bojorkez-Calderon, Hannah Imson

Featured Research

The purpose of this investigation was to observe the differences between the photosynthetic rates and photo-protection of young, red, juvenile leaves of Malosma laurina, and compare it to young, green leaves. To accomplish this, the open-system of Li-6400 XT was brought out into the field to a shrub of Malosma laurina that was flourishing and had both red and green leaves present. Then, data of fluorescence, photosynthetic rate, and conductance was taken from both red leaves and green leaves, and the photosynthetic rates were compared. Through this investigation, we were able to quantify that in young, red leaves, which had …