Biochemistry, Biophysics, and Structural Biology Commons^™

Microstructural Changes To Proso Millet Protein Bodies Upon Cooking And Digestion, Paridhi Gulati, You Zhou, Christian Elowsky, Devin J. Rose

Department of Food Science and Technology: Faculty Publications

Cooking results in a drastic decline in digestibility of proso millet proteins, panicins. Scanning electron and confocal microscopy were used to observe morphological changes in proso millet protein bodies upon cooking and digestion that could be associated with the loss in digestibility. Spherical protein bodies (1–2.5 mm) were observed in proso millet flour and extracted protein. Cooking did not result in any noticeable change in the size or shape of the protein bodies. However, upon digestion with pepsin the poor digestibility of cooked proso millet protein was clearly evident from the differences in microstructure of the protein bodies: large cavities …

การพัฒนาอุปกรณ์วิเคราะห์ฐานกระดาษสำหรับหาปริมาณสารเพรดนิโซโลนและเดกซาเมทาโซนที่ปลอมปนในผลิตภัณฑ์สมุนไพรด้วยวิธีเคมีไฟฟ้า, วิศรุต พริ้มพราย

Chulalongkorn University Theses and Dissertations (Chula ETD)

การปลอมปนของสารสเตียรอยด์ชนิดเดกซาเมทาโซนและเพรดนิโซโลนในผลิตภัณฑ์สมุนไพรเป็นปัญหาสำคัญที่ก่อผลเสียร้ายแรงต่อสุขภาพของผู้ใช้ ในหลาย ๆ ประเทศทั่วโลก โดยเฉพาะอย่างยิ่งในประเทศกำลังพัฒนา งานวิจัยนี้ ประสบความสำเร็จในการพัฒนาอุปกรณ์สำหรับแยกและตรวจวัดปริมาณการปลอมปนของสารสเตียรอยด์ดังกล่าว โดยใช้อุปกรณ์ตรวจวิเคราะห์ฐานกระดาษและใช้หลักการทางเคมีไฟฟ้า (electrochemical paper-based analytical device หรือ ePAD) ซึ่งประกอบด้วยกระดาษ Whatman SG81 ตลับพลาสติกจากการพิมพ์สามมิติ และขั้วไฟฟ้าชนิด screen printed electrode โดยกระดาษ Whatman SG81 ใช้สำหรับแยกสารสเตียรอยด์ชนิดเดกซาเมทาโซนและเพรดนิโซโลน โดยใช้วัฏภาคเคลื่อนที่เป็นสารละลาย 60% ethyl acetate ใน cyclohexane ซึ่งผลการศึกษาพบว่าสามารถแยกสารสเตียรอยด์ดังกล่าวออกจากสิ่งเจือปนต่าง ๆ ได้ภายใน 7 นาที สารสเตียรอยด์ที่แยกออกจากกันบนกระดาษ นำมาวัดปริมาณด้วยเทคนิคเคมีไฟฟ้าชนิด differential pulse voltammetry โดยใช้ตลับพลาสติกจากการพิมพ์สามมิติที่ถูกออกแบบทำให้สารละลายอิเล็กโทรไลต์ถูกขังอยู่บนกระดาษ ทำให้สามารถตรวจวัดสัญญาณทางเคมีไฟฟ้าได้คงที่ ซึ่งอุปกรณ์ที่พัฒนาขึ้นสามารถตรวจวัดปริมาณปลอมปนของสารสเตียรอยด์ทั้งชนิดเดกซาเมทาโซนและ เพรดนิโซโลนได้ในช่วงความเข้มข้นระหว่าง 10 ถึง 500 µg/mL โดยมีค่าสัมประสิทธิ์สหสัมพันธ์เท่ากับ 0.988 และ 0.994 ตามลำดับ มีขีดจำกัดในการตรวจวิเคราะห์เชิงคุณภาพเท่ากับ 3.59 µg/mL และ 6.00 µg/mL ตามลำดับ และขีดจำกัดในการตรวจวิเคราะห์เชิงปริมาณมีค่าเท่ากับ 11.98 µg/mL และ 20.02 µg/mL ตามลำดับ การตรวจวัดปริมาณปลอมปนของสารสเตียรอยด์ทั้งสองชนิดในสิ่งตัวอย่างผลิตภัณฑ์สมุนไพรจริงด้วยวิธีที่พัฒนาขึ้นมีค่าสอดคล้องกับผลที่ตรวจด้วยวิธี HPLC และเป็นวิธีที่ใช้งานง่าย มีต้นทุนต่ำ รวดเร็ว และมีศักยภาพนำไปใช้ตรวจหาสิ่งตัวอย่างผลิตภัณฑ์สมุนไพรที่สงสัยว่ามีการปลอมปนของสารสเตียรอยด์ ในระดับภาคสนาม

Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack

Dissertations and Theses

Thymic epithelial cells (TEC) are essential for a proper adaptive immune response by regulating thymocyte development and establishing central tolerance. In the thymus, TECs differentially express Wnt proteins, which activate canonical and non-canonical Wnt signaling pathways. Wnt signaling is thought to regulate cell survival, proliferation, and development although the direct molecular mechanisms in TECs have yet to be elucidated. The inducible inhibition of canonical Wnt signaling with Dkk1 leads to a rapid loss of TEC progenitors as well as a decline in mature Aire-expressing mTECs. Therefore, we explore the role of Wnt ligands potentially responsible for stimulating and/or regulating Wnt …

Implementation And Performance Comparison Of Some Heuristic Algorithms For Block Sorting, Sandhya Turlapaty

UNF Graduate Theses and Dissertations

An implementation framework has been developed in this thesis for a well-known APX-hard combinatorial optimization problem known as Block Sorting. The motivation for the study of this problem comes from applications such as computational biology and optical character recognition. While existing Block Sorting research has been theoretically focused on the development and analysis of several approximation algorithms for Block Sorting, little or no work has been carried out thus far on the implementation of the proposed approximation algorithms. The conceptualization of an implementation framework and illustrating its use by experimenting with the existing approximation algorithms will provide means for discovering …

Quantitation Without Calibration: Response Profile As An Indicator Of Target Amount, Mrittika Debnath

Graduate Research Theses & Dissertations

Quantitative assessment of biomarkers is essential in numerous contexts from decision-making in clinical situations to food quality monitoring to the interpretation of life-science research findings. However, appropriate quantitation techniques are not as widely addressed as detection methods. One of the major challenges in biomarker’s quantitation is the need to have a calibration for correlating a measured signal to a target amount. The step complicates the methodologies and makes them less sustainable. In this work, we addressed the issue via a new strategy: relying on the position of response profile rather than absolute signal for assessment of a target nucleic acid’s …

Quantifying The Differences In Binding Affinity Of Reduced Glutathione For Glutathione S-Transferase At Ph 6.5 And 8.5 Using Isothermal Titration Calorimetry, Clay P. Renshaw Jr., Ronald K. Gary

McNair Poster Presentations

The binding affinity between an enzyme and its substrate is often dependent on the pH of the local environment. Knowing the pH at which reduced glutathione (GSH) binds with the highest affinity to the enzyme glutathione S-transferase (GST) is useful for determining the optimal pH for purification of GST-fusion proteins during GST-affinity chromatography. In this study, GST of the species Schistosoma japonicum was purified, quantified, and utilized to study its binding interaction with GSH at pH 6.5 and 8.5 via isothermal titration calorimetry (ITC). After protein expression, extraction, and purification, the GST concentration was quantified using Qubit^TM fluorometry. …

Synthesis, Characterisation And Dna Intercalation Studies Of Regioisomers Of Ruthenium (Ii) Polypyridyl Complexes, Laura Perdisatt, Samar Moqadasi, Luke O'Neill, Gary Hessman, Alessandra Ghion, Muhammad Qasim Mushtaq Warraich, Alan Casey, Christine O'Connor

Articles

Regioisomers of the functional group of the main ligand (L) on a series of [Ru(phen)2L]2+and [Ru(bpy)2L]2+ complexes, where phen is 1,10 phenanthroline and bpy is 2,2′-bipyridine, were synthesised to investigate the interaction with deoxyribonucleic acid (DNA) as potential therapeutics. UV–Vis binding titrations, thermal denaturation and circular dichroism were used to evaluate their interaction with DNA. The conclusions indicated the significance of the auxiliary ligand; especially 1,10-phenanthroline has on the binding constants (Kb). The systematic variation of auxiliary ligand(phen or bpy), and polypyridyl ligand (4-(1H-Imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzonitrile (CPIP), 2-(4-formylphenyl)imidazo[4,5-f] [1,10] phenanthroline (FPIP), 2-(4-bromophenyl)imidazo[4,5-f][1,10]phenanthroline (BPIP) and 2-(4-nitrophenyl)imidazo[4,5-f] [1,10] phenanthroline (NPIP), split in terms of …

Determining The Role Played By Aryl Hydrocarbon Receptor (Ahr) In The Colon Carcinoma Tumor Model, Poonam Yakkundi

University of the Pacific Theses and Dissertations

Aryl hydrocarbon receptor (AHR), commonly known as an environmental sensor involved in the metabolism and elimination of xenobiotic substances, is also an important modulator in the development and functioning of the immune system. AHR expression is varied in the T cell subsets with the highest expression in T-helper 17 and T regulatory cells. Work from many researchers has suggested that AHR can act as a tumor promoter or a tumor suppressor depending on the tumor type. Our goal is to understand the role played by AHR in MC38 syngeneic colon carcinoma tumor model. In the absence of AHR, MC38 tumor …

Characterization Of Tetraethyl Orthosilicate-Based Dynamic Hydrogels For Use As Reversible 3-D Cell Culture Matrices, Krisitan Stipe

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

Quantitative Genetics Of Populus, Roba Bdeir

Dissertations, Master's Theses and Master's Reports

Evidence for bark, stem and stomatal density adaptation to different climates in the model species Populus is seen in both the natural population as well as in the greenhouse, but the genetic basis of these adaptation remains poorly understood. The present thesis investigates bark texture, bark thickness, diameter and stomatal density variations among Populus population using two quantitative genetics methods to attempt understand the genetic system controlling inheritance of these traits and to associate them with respective genes. The first approach aimed at detecting quantitative trait loci (QTL) associated with all phenotypic traits in an interspecific hybrid pedigree (Populus …

Assembly And Trafficking Of The Cystic Fibrosis Transmembrane Conductance Regulator And Associated Proteins, Zhihui Zhang

Theses and Dissertations--Chemistry

Cystic Fibrosis (CF) is an autosomal recessive genetic disease that leads to severe malfunction in many organs, but particularly the lungs. The primary cause of this malfunction is the decrease of the airway surface liquid layer on the lung epithelium. The lack of hydration leads to mucus build up on the epithelial lining, leading to blockage of airways. The underlying cause of CF is the dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR), which results from mutations in the protein. Almost 90% of CF patients are caused by the deletion of the phenylalanine at position 508 of CFTR, which …

Evaluation Of Ispe For Inhibitor Design In The Non-Mevalonate Pathway, Kataryzna Barbara Hoerchler

Graduate Research Theses & Dissertations

There is an urgent need to discover new antibiotics to combat the emergence of drug resistant Novel antibiotics that target unique pathways different from existing therapies are promising targets. The non-mevalonate pathway (MEP), which was discovered in the 1990’s, is essential for most bacteria, plants and apicomplexan parasites. Inhibition of the non-mevalonate is an attractive pharmaceutical target, since it is not present in mammals. Many compounds have surfaced as potential inhibitors, but none have made it to market. This thesis investigates the fourth step in the MEP pathway involving the enzyme 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase (IspE) from Escherichia coli (Ec), Burkholderia thailandensis …

Understanding Carbohydrate Recognition Mechanisms In Non-Catalytic Proteins Through Molecular Simulations, Abhishek A. Kognole

Theses and Dissertations--Chemical and Materials Engineering

Non-catalytic protein-carbohydrate interactions are an essential element of various biological events. This dissertation presents the work on understanding carbohydrate recognition mechanisms and their physical significance in two groups of non-catalytic proteins, also called lectins, which play key roles in major applications such as cellulosic biofuel production and drug delivery pathways. A computational approach using molecular modeling, molecular dynamic simulations and free energy calculations was used to study molecular-level protein-carbohydrate and protein-protein interactions. Various microorganisms like bacteria and fungi secret multi-modular enzymes to deconstruct cellulosic biomass into fermentable sugars. The carbohydrate binding modules (CBM) are non-catalytic domains of such enzymes that …

Protein Engineering In The Study Of Protein Labeling And Degradation, Xinyi Zhang

Theses and Dissertations--Chemistry

Proteins are large macromolecules that play important roles in nature. With the development of modern molecular biology techniques, protein engineering has emerged as a useful tool and found many applications in areas ranging from food industry, environmental protection, to medical and life science. Biomimetic membrane incorporates biological elements, such as proteins, to form membranes that mimic the high specificity and conductance of natural biological membranes. For any application involving the usage of proteins, the first barrier is always the production of proteins with sufficient stability, and the incorporation of proteins into the artificial matrix. This thesis contains two major parts, …

Applications Of Cell-Derived Vesicles: From Single Molecule Studies To Drug Delivery, Faruk H. Moonschi

Theses and Dissertations--Chemistry

Single molecule studies can provide information of biological molecules which otherwise is lost in ensemble studies. A wide variety of fluorescence-based techniques are utilized for single molecule studies. While these tools have been widely applied for imaging soluble proteins, single molecule studies of transmembrane proteins are much more complicated. A primary reason for this is that, unlike membrane proteins, soluble proteins can be easily isolated from the cellular environment. One approach to isolate membrane proteins into single molecule level involves a very low label expression of the protein in cells. However, cells generate background fluorescence leading to a very low …

Protein Suppression Of Flavin Semiquinone As A Mechanistically Important Control Of Reactivity: A Study Comparing Flavoenzymes Which Differ In Redox Properties, Substrates, And Ability To Bifurcate Electrons, John Patrick Hoben

Theses and Dissertations--Chemistry

A growing number of flavoprotein systems have been observed to bifurcate pairs of electrons. Flavin-based electron bifurcation (FBEB) results in products with greater reducing power than that of the reactants with less reducing power. Highly reducing electrons at low reduction midpoint potential are required for life processes of both aerobic and anaerobic metabolic processes. For electron bifurcation to function, the semiquinone (SQ) redox intermediate needs to be destabilized in the protein to suppress its ability to trap electrons. This dissertation examines SQ suppression across a number of flavin systems for the purpose of better understanding the nature of SQ suppression …

The Rtfa Gene Regulates Plant And Animal Pathogenesis And Secondary Metabolism In Aspergillus Flavus, Jessica Michelle Lohmar

Graduate Research Theses & Dissertations

Aspergillus flavus is an opportunistic fungal plant and human pathogen and producer of mycotoxins including aflatoxin B1 (AFB1). As part of our ongoing studies to elucidate biological functions of the A. flavus rtfA gene, we examined its role in pathogenicity of both plant and animal model systems. rtfA encodes a putative RNA-Pol II transcription elongation factor, previously characterized in Saccharomycese cerevisiae, Aspergillus nidulans, Aspergillus fumigatus, where it was shown to regulate several important cellular processes, including morphogenesis, secondary metabolism. In addition, an initial study in A. flavus indicated that rtfA also influences development and production of AFB1, however its effect …

Study Of The Mechanism Of Action For Ru(Ii) Polypyridyl Complexes As Potential Anticancer Agents, Yang Sun

Theses and Dissertations--Chemistry

Application of chemotherapeutic agents in current cancer treatment has been limited by adverse effects as poor selectivity results in systemic toxicity; most chemotherapy approaches also experience inherited or acquired drug resistance which lead to reduced treatment outcome. Research efforts have focused on the discovery of novel chemotherapies that overcome the limitations mentioned above. Ru(II) polypyridyl complexes with anti-cancer properties have been extensively studied as traditional cytotoxic agents and photodynamic therapy agents due to their photophysical and photochemical characteristics.

Most research has focused on the design of Ru(II) polypyridyl complexes that have affinities to nucleic acids as inspired by the classic …

Journey To The Center Of The Protein: Allostery From Multitemperature Multiconformer X-Ray Crystallography, Daniel A. Keedy

Advanced Science Research Center

Proteins inherently fluctuate between conformations to perform functions in the cell. For example, they sample product-binding, transition-state-stabilizing and product-release states during catalysis, and they integrate signals from remote regions of the structure for allosteric regulation. However, there is a lack of understanding of how these dynamic processes occur at the basic atomic level. This gap can be at least partially addressed by combining variable-temperature (instead of traditional cryogenic temperature) X-ray crystallography with algorithms for modeling alternative conformations based on electron-density maps, in an approach called multitemperature multiconformer X-ray crystallography (MMX). Here, the use of MMX to reveal alternative conformations at …

Characterizing The Requirement Of The Cmi/Trr Compass-Like Complex During Drosophila Development, Timothy Nickels

Master's Theses

The MLR family of COMPASS-like complexes are histone methyltransferase complexes that are associated with the activation of gene enhancers. In D. melanogaster, Cara mitad (Cmi, also known as Lpt) and Trithorax related (Trr) are central subunits of a complex orthologous to mammalian Lysine methyltransferase 2 C and D (KMT2C and KMT2D, also known as MLL3 and MLL2/4) that catalyze H3K4 monomethylation. Previous studies have demonstrated that mutations in these genes are associated with cancer and developmental disorders, but the mechanisms by which these alterations contribute to disease states are unknown. The Cmi-containing COMPASS-like complex and orthologous vertebrate complexes have been …