Engineering New Bio-Based Carbon Capture Solutions to Bridge the Global Food Gap

Description
By 2050, feeding the world will require a 70% increase in food production with fewer water resources due to climate change. New strategies are needed to replace current approaches. C3 photosynthesis is inefficient due to photorespiration, but synthetic biology offers

By 2050, feeding the world will require a 70% increase in food production with fewer water resources due to climate change. New strategies are needed to replace current approaches. C3 photosynthesis is inefficient due to photorespiration, but synthetic biology offers a way to increase photosynthetic efficiency and crop yields, such as the tartronyl-CoA (TaCo) pathway. This project assesses the TaCo pathway in the chloroplast of Chlamydomonas reinhardtii and represents a pivotal step toward its practical application in higher plants for use in agriculture and biotechnology.
Date Created
2024-05
Agent

Engineering New Bio-Based Carbon Capture Solutions to Bridge the Global Food Gap

Description
By 2050, feeding the world will require a 70% increase in food production with fewer water resources due to climate change. New strategies are needed to replace current approaches. C3 photosynthesis is inefficient due to photorespiration, but synthetic biology offers

By 2050, feeding the world will require a 70% increase in food production with fewer water resources due to climate change. New strategies are needed to replace current approaches. C3 photosynthesis is inefficient due to photorespiration, but synthetic biology offers a way to increase photosynthetic efficiency and crop yields, such as the tartronyl-CoA (TaCo) pathway. This project assesses the TaCo pathway in the chloroplast of Chlamydomonas reinhardtii and represents a pivotal step toward its practical application in higher plants for use in agriculture and biotechnology.
Date Created
2024-05
Agent

Mechanism of the FO Motor in the F-ATP Synthase

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Description
The FOF1 ATP synthase is responsible for generating the majority of adenosine triphosphate (ATP) in almost all organisms on Earth. A major unresolved question is the mechanism of the FO motor that converts the transmembrane flow of protons into rotation

The FOF1 ATP synthase is responsible for generating the majority of adenosine triphosphate (ATP) in almost all organisms on Earth. A major unresolved question is the mechanism of the FO motor that converts the transmembrane flow of protons into rotation that drives ATP synthesis. Using single-molecule gold nanorod experiments, rotation of individual FOF1 were observed to measure transient dwells (TDs). TDs occur when the FO momentarily halts the ATP hydrolysis rotation by the F1-ATPase. The work presented here showed increasing TDs with decreasing pH, with calculated pKa values of 5.6 and 7.5 for wild-type (WT) Escherichia coli (E. coli) subunit-a proton input and output half-channels, respectively. This is consistent with the conclusion that the periplasmic proton half-channel is more easily protonated than the cytoplasmic half-channel. Mutation in one proton half-channel affected the pKa values of both half-channels, suggesting that protons flow through the FO motor via the Grotthuss mechanism. The data revealed that 36° stepping of the E. coli FO subunit-c ring during ATP synthesis consists of an 11° step caused by proton translocations between subunit-a and the c-ring, and a 25° step caused by the electrostatic interaction between the unprotonated c-subunit and the aR210 residue in subunit-a. The occurrence of TDs fit to the sum of three Gaussian curves, which suggested that the asymmetry between the FO and F1 motors play a role in the mechanism behind the FOF1 rotation. Replacing the inner (N-terminal) helix of E. coli c10-ring with sequences derived from c8 to c17-ring sequences showed expression and full assembly of FOF1. Decrease in anticipated c-ring size resulted in increased ATP synthesis activity, while increase in c-ring size resulted in decreased ATP synthesis activity, loss of Δψ-dependence to synthesize ATP, decreased ATP hydrolysis activity, and decreased ACMA quenching activity. Low levels of ATP synthesis by the c12 and c15-ring chimeras are consistent with the role of the asymmetry between the FO and F1 motors that affects ATP synthesis rotation. Lack of a major trend in succinate-dependent growth rates of the chimeric E. coli suggest cellular mechanisms that compensates for the c-ring modification.
Date Created
2023
Agent

Genome to Phenome: From 3-D Structural Analysis to Experimental Validation for the Functional Properties of Pocillopora damicornis Proteins

Description

Oceanic life is facing the deleterious aftermath of coral bleaching. To reverse the damages introduced by anthropological means, it is imperative to study fundamental properties of corals. One way to do so is to understand the metabolic pathways and protein

Oceanic life is facing the deleterious aftermath of coral bleaching. To reverse the damages introduced by anthropological means, it is imperative to study fundamental properties of corals. One way to do so is to understand the metabolic pathways and protein functions of corals that contribute to the resilience of coral reefs. Although genomic sequencing and structural modeling has yielded significant insights for well-studied organisms, more investigation must be conducted for corals. Better yet, quantifiable experiments are far more crucial to the understanding of corals. The objective is to clone, purify, and assess coral proteins from the cauliflower coral species known as Pocillopora damicornis. Presented here is the pipeline for how 3-D structural modeling can help support the experimental data from studying soluble proteins in corals. Using a multi-step selection approach, 25 coral genes were selected and retrieved from the genomic database. Using Escherischia coli and Homo sapiens homologues for sequence alignment, functional properties of each protein were predicted to aid in the production of structural models. Using D-SCRIPT, potential pairwise protein-protein interactions (PPI) were predicted amongst these 25 proteins, and further studied for identifying putative interfaces using the ClusPro server. 10 binding pockets were inferred for each pair of proteins. Standard cloning strategies were applied to express 4 coral proteins for purification and functional assays. 2 of the 4 proteins had visible bands on the Coomassie stained gel and were able to advance to the purification step. Both proteins exhibited a faint band at the expected migration distance for at least one of the elutions. Finally, PPI was carried out by mixing protein samples and running in a native gel, resulting in one potential pair of PPI.

Date Created
2023-05
Agent

Baby Bug: Exploring the Effects of Ethnicity and Socioeconomic Status on Infant Gut Microbiome Diversity and Childhood Obesity

Description

The incidence of childhood obesity has become increasingly prevalent in the United States in recent years. The development of obesity at any age, but especially in adolescence, can have lasting negative effects in the form of cardiometabolic disease, increased incurred

The incidence of childhood obesity has become increasingly prevalent in the United States in recent years. The development of obesity at any age, but especially in adolescence, can have lasting negative effects in the form of cardiometabolic disease, increased incurred healthcare costs, and potential negative effects on quality of life. In recent years, a rising trend of obesity, in both adults and adolescents, has been observed in lower income and ethnic groups. Increased adiposity can be influenced by modifiable factors -(physical activity, caloric intake, or sleep) or by non-modifiable factors (ethnicity, genetic predispositions, and socioeconomic status). The influence of these factors can be observed in individuals of all ages, including infants. A common indicator of the development of childhood obesity is rapid weight gain (RWG) within an infant’s first year of life. The composition of the gut microbiome can act as a predictor for RWG and the development of childhood obesity. Infants are exposed to an immense microbial load when they are born and their gut microbiome is continually diversified through their method of feeding and the subsequent introduction to solid foods. While currently understudied, it is understood that cultural and socioeconomic factors influence the development of the gut microbiome, which is further explored in this analysis. The DNA from 51 fecal samples from infants ranging from 3 weeks to 12 months in age was extracted and sequenced using next-generation sequencing, and the resulting sequences were analyzed using QIIME 2. Results from alpha-diversity and beta-diversity metrics showed significant differences in the gut microbiome of infants when comparing groups based on baby race/ethnicity, household income, and mom’s education. These findings suggest the importance of sociodemographic characteristics in shaping the gut microbiome and suggest the importance of future studies including diverse populations in gut microbiome work.

Date Created
2023-05
Agent

A Structure Guided Approach to Understanding Photosynthetic Membrane Proteins

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Description
First evolving in cyanobacteria, the light reactions of oxygenic photosynthesis are carried out by the membrane proteins, photosystem II and photosystem I, located in the thylakoid membrane. Both utilize light captured by their core antenna systems to catalyze a charge

First evolving in cyanobacteria, the light reactions of oxygenic photosynthesis are carried out by the membrane proteins, photosystem II and photosystem I, located in the thylakoid membrane. Both utilize light captured by their core antenna systems to catalyze a charge separation event at their respective reaction centers and energizes electrons to be transferred energetically uphill, eventually to be stored as a high energy chemical bond. These protein complexes are highly conserved throughout different photosynthetic lineages and understanding the variations across species is vital for a complete understanding of how photosynthetic organisms can adapt to vastly different environmental conditions. Most knowledge about photosynthesis comes from only a handful of model organisms grown under laboratory conditions. Studying model organisms has facilitated major breakthroughs in understanding photosynthesis, however, due to the vast global diversity of environments where photosynthetic organisms are found, certain aspects of this process may be overlooked or missed by focusing on a select group of organisms optimized for studying in laboratory conditions. This dissertation describes the isolation of a new extremophile cyanobacteria, Cyanobacterium aponinum 0216, from the Arizona Sonoran Desert and its innate ability to grow in light intensities that exceed other model organisms. A structure guided approach was taken to investigate how the structure of photosystem I can influence the spectroscopic properties of chlorophylls, with a particular focus on long wavelength chlorophylls, in an attempt to uncover if photosystem I is responsible for high light tolerance in Cyanobacterium aponinum 0216. To accomplish this, the structure of photosystem I was solved by cryogenic electron microscopy to 2.7-anstrom resolution. By comparing the structure and protein sequences of Cyanobacterium aponinum to other model organisms, specific variations were identified and explored by constructing chimeric PSIs in the model organism Synechocystis sp. PCC 6803 to determine the effects that each specific variation causes. The results of this dissertation describe how the protein structure and composition affect the spectroscopic properties of chlorophyll molecules and the oligomeric structure of photosystem I, possibly providing an evolutionary advantage in the high light conditions observed in the Arizona Sonoran Desert.
Date Created
2022
Agent

Measuring Quinone Reduction in Heliomicrobium modesticaldum’s Reaction Center

Description

The objective of this study is to create a spectrophotometric assay that can measure quinone reduction in the HbRC. The key techniques used in the project consisted of a PCR, a pseudo golden gate, a transformation into E. coli, a

The objective of this study is to create a spectrophotometric assay that can measure quinone reduction in the HbRC. The key techniques used in the project consisted of a PCR, a pseudo golden gate, a transformation into E. coli, a conjugation into Heliomicrobium modesticaldum, a growth study, a HbRC prep, and absorbance spectroscopy. PCR was crucial for amplifying the Cyt c553-PshX gene for the pseudo golden gate. The pseudo golden gate ligated Cyt c553-PshX into the plasmid pMTL86251 in order to transform the plasmid with the desired gene into the E. coli strain S17-1. This E. coli strain allows for conjugation into H. modesticaldum. H. modesticaldum cannot uptake DNA by itself, so the E. coli creates a pilus to transfer the desired plasmid to H. modesticaldum. The growth study was crucial for determining if H. modesitcaldum could be induced using xylose without killing the cells or inhibiting the growth in such a way that the project could not be continued. The HbRC prep was used to isolate and purify the Cyt c553-PshX protein. Absorbance spectroscopy and JTS kinetic assay was used to characterize and confirm that the protein eluted from the affinity column was Cyt c553-PshX. The results of the absorbance spectra and JTS kinetic assay confirmed that Cyt c553-PshX was not made. The study is currently being continued using a new system that utilizes SpyCatcher SpyTag covalent linkages in order to attach cytochrome to reduce P800 to the HbRC.

Date Created
2022-12
Agent

Carbon and Nitrogen Content and Isotopic Composition of Heliomicrobium Modesticaldum Under Different Growth Conditions

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Description
All known life requires three main metabolic components to grow: an energy source, an electron source, and a carbon source. For energy, an organism can use light or chemical reactions. For electrons, an organism can use metals or organic molecules.

All known life requires three main metabolic components to grow: an energy source, an electron source, and a carbon source. For energy, an organism can use light or chemical reactions. For electrons, an organism can use metals or organic molecules. For carbon, an organism can use organic or inorganic carbon. Life has adapted to use any mixture of the endpoints for each of the three metabolic components. Understanding how these components are incorporated in a living bacterium on Earth in modern times is relatively straight forward. This becomes much more complicated when trying to determine what metabolisms may have been used in ancient times on Earth or potential novel metabolisms that exist on other planets. One way to examine these possibilities is by creating genetically modified mutant bacteria that have novel metabolisms or proposed ancient metabolisms to study. This thesis is the beginning of a broader study to understand novel metabolisms using Heliobacteria modesticaldum. H. modesticaldum was grown under different environmental conditions to isolate the impacts of energy, electron, and carbon sources on carbon and nitrogen isotope fractionation. Additionally, the wild type and a novel mutant H. modesticaldum were compared to measure the effects of specific enzymes on carbon and nitrogen isotope fractionation. By forcing the bacterium to adapt to different conditions, variation in carbon and nitrogen content and isotopic signature are detected. Specifically, by forcing the bacterium to fix nitrogen as opposed to nitrogen incorporation, the isotopic signature of the bacterium had a noticeable change. Themutant H. modesticaldum also had a different isotopic signature than the wild type. Without the enzyme citrate synthase, H. modesticaldum had to adapt its carbon metabolic cycle, creating a measurable carbon isotope fractionation. The results described here offer new insight into the effects of metabolism on carbon and nitrogen fractionation of ancient or novel organisms.
Date Created
2021
Agent

Tungsten Palladium Plates for Assaying H2 Catalysis by Cyt b562-CoPPIX

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Description

Hybrid metalloproteins incorporating synthetic organometallic active sites within a protein scaffold are being researched as viable catalysts for the production of hydrogen fuel. Our group and others have shown that the incorporation of cobalt protoporphyrin IX in cytochrome b₅₆₂ yields

Hybrid metalloproteins incorporating synthetic organometallic active sites within a protein scaffold are being researched as viable catalysts for the production of hydrogen fuel. Our group and others have shown that the incorporation of cobalt protoporphyrin IX in cytochrome b₅₆₂ yields artificial enzymes that reduce protons to molecular hydrogen in the presence of photoinductive light and photosensitizers. Using random mutagenesis via error-prone PCR we have created a library of mutants to use in directed evolution to optimize hydrogen catalysis, though a challenge in this project is that testing individual variants by gas chromatography is not feasible on a large scale. For this reason, we are developing a gasochromic, hydrogen assay that is based on the interaction of molecular hydrogen with tungsten trioxide with a palladium catalyst. Initially, results show this assay to be qualitatively accurate between trials; however, its application in screening remains a challenge.

Date Created
2022-05
Agent

Mechanisms of Photodegradation of Fe Catalysts and Small Organic Molecules

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Description

This thesis is about how Fe catalysts can be degraded using photocatalysis and how Fe catalysts can degrade small molecules in conjunction with light. The goal of this paper is to look further into more sustainable methods of organic chemistry.

This thesis is about how Fe catalysts can be degraded using photocatalysis and how Fe catalysts can degrade small molecules in conjunction with light. The goal of this paper is to look further into more sustainable methods of organic chemistry. Many current organic chemistry practices involve the use of precious metals. Iron is a more sustainable catalyst because it is abundant and inexpensive which is important for preserving the earth and making the organic chemistry more accessible. Along the same lines, light is a renewable energy source and has demonstrated its ability to aid in reactions. Overall, the goal of this paper is to explore the more sustainable alternatives to harsh and toxic organic chemistry practices through the use of Iron and light.

Date Created
2022-05
Agent