2020 Gardner Alexander 1581

Total Page:16

File Type:pdf, Size:1020Kb

2020 Gardner Alexander 1581 This electronic thesis or dissertation has been downloaded from the King’s Research Portal at https://kclpure.kcl.ac.uk/portal/ The influence of salivary metabolite composition on taste and oral perception Gardner, Alex Awarding institution: King's College London The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without proper acknowledgement. END USER LICENCE AGREEMENT Unless another licence is stated on the immediately following page this work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence. https://creativecommons.org/licenses/by-nc-nd/4.0/ You are free to copy, distribute and transmit the work Under the following conditions: Attribution: You must attribute the work in the manner specified by the author (but not in any way that suggests that they endorse you or your use of the work). Non Commercial: You may not use this work for commercial purposes. No Derivative Works - You may not alter, transform, or build upon this work. Any of these conditions can be waived if you receive permission from the author. Your fair dealings and other rights are in no way affected by the above. Take down policy If you believe that this document breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 11. Oct. 2021 THE INFLUENCE OF SALIVARY METABOLITE COMPOSITION ON TASTE AND ORAL PERCEPTION Thesis submitted for the degree of DOCTOR OF PHILOSOPHY By ALEXANDER GARDNER Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London December 2019 Supervisors: Professor Guy Carpenter and Dr. Po-Wah So 1 Summary Metabolomics is the study of the small molecules that are present within a biological sample or system. Metabolomic analysis is yielding ever-increasing new information about the role of metabolites in health and disease. Much of the literature to date has focused on biofluids such as urine or plasma although saliva is increasingly being identified as an important fluid for metabolomic study. Functional roles for metabolites generated in the gut are being discovered, in relation to both health and disease, however little is known about the role(s) salivary metabolites play in health. Taste perception is an important physiological process occurring in the oral cavity that has wide reaching implications for health and it has been speculated that the metabolic composition of saliva may influence taste perception. This thesis explores the metabolic composition of saliva with particular emphasis on relationships with taste perception and other oral sensations such as astringency. Other questions that are addressed include the role of the oral microbiome in shaping the metabolic composition of saliva and the association between the metabolic composition and physical properties of saliva. The main analytical platform for metabolomic profiling of saliva was proton nuclear magnetic resonance spectroscopy (1H-NMR). In the first instance, validation of the analytical and sensory methodologies adopted throughout this thesis were conducted, to satisfy that subsequent data gathering was valid. It was then found, through a combination of in-vivo and in-vitro analyses, that the salivary metabolome is largely shaped by oral bacteria. The most concentrated salivary metabolites such as the short chain fatty acids (SCFAs) acetate, butyrate and propionate are of microbial origin whereas metabolites such as lactate, citrate and urea are of host origin. Furthermore, oral bacteria were shown in-vitro to catabolise salivary proteins and endogenous metabolites, generating abundant SCFAs and other salivary metabolites. Modulating effects of gustatory reflexes on salivary metabolic composition were then investigated for sucrose (sweet), caffeine (bitter), menthol (cooling) and capsaicin (warming). Sucrose was found to be rapidly catabolised by oral bacteria, generating abundant metabolites such as pyruvate and lactate, whereas capsaicin stimulation increased citrate concentrations. Citrate was also found to relate to the extensional rheology of capsaicin-stimulated saliva. Assessment of the relationship between taste perception and salivary composition was approached from two angles. Firstly, taste recognition and detection thresholds were 2 assessed in a taste panel. A positive association between salivary urea and sucrose detection threshold was discovered. As urea was found to be consumed by oral bacteria, inversely correlating with salivary bacterial load, it is speculated that differences in salivary urea between sensitive and insensitive glucose detectors might reflect differences in the composition and/or function of the oral microbiome. Additional findings relating to the salivary metabolome that stemmed from this thesis include an apparent lack of any significant genetic contribution to the salivary metabolome and a significantly higher degree of intra- individual stability compared to inter-individual stability of salivary metabolite profile. Subsequently, suprathreshold taste perception of sucrose, aspartame, caffeine, black tea and oleic acid (sweet, sweet, bitter, astringent, fatty; respectively) and salivary composition was assessed in a twin study. Generally, twins with discordant tastes as well as unrelated individuals with different tastes has similar differences in their saliva composition. Twins with similar levels of taste perception did not display these salivary differences. Invariably, these relationships were inverse i.e. higher metabolite concentration was associated with reduced taste sensitivity. Salivary composition therefore appeared to be an important local environmental factor in determining sensitivity to certain taste stimuli. Controlling for salivary flow rate also emerged as important, as higher flow rate was associated with lower metabolite concentrations and improved sensitivity. This suggested that the degree to which salivary fluid dilutes microbial-produced metabolites in the mouth may impact on taste perception. There was no evidence of a general inhibitory metabolite across the different tastants although taurine was associated with both sucrose and oleic acid perception. Collectively, this work found that the salivary metabolome represents a complex balance between host and microbial metabolic activity. It can be concluded that there is evidence of associations between salivary metabolite composition and taste perception. Certain metabolites of microbial origin were inversely associated with taste perception, and an endogenous metabolite known to be consumed by oral bacteria (urea) was positively associated with sucrose detection. The findings of this work support the emerging role of metabolomics as a functional measure of complex microbial communities in relation to host physiology. While the findings of this work cannot be used to infer a causal relationship between specific metabolites and taste, target salivary metabolites for future study in association with taste perception are identified. 3 List of Publications and Presentations Publications: Gardner, A., Parkes, H.G., Carpenter, G.H. and So, P.W., 2018. Developing and Standardizing a Protocol for Quantitative Proton Nuclear Magnetic Resonance (1H NMR) Spectroscopy of Saliva. Journal of proteome research, 17(4), pp.1521-1531. Gardner, A., Parkes, H.G., So, P.W. and Carpenter, G.H., 2019. Determining bacterial and host contributions to the human salivary metabolome. Journal of Oral Microbiology, 11:1, DOI: 10.1080/20002297.2019.1617014. Gardner, A. & Carpenter, G.H., 2019. Anatomical stability of human fungiform papillae and relationship with oral perception measured by salivary response and intensity rating. Scientific Reports, 9(1). Gardner, A., So, P-W, Carpenter, G. 2019. Endogenous salivary citrate is associated with enhanced rheological properties following oral capsaicin-stimulation. Experimental Physiology, 1-12. Presentations: Year Conference Title 2019 British Society for Oral and Oral: “Sweet Tooth” is Associated with Dental Research, Leeds, UK Altered Intra-oral Sucrose Metabolism 2018 International Association for Poster: Influence of Oral Bacterial Dental Research, London UK Metabolism on Sucrose Taste Perception 2018 Food Oral Processing, Short oral and poster: The Influence of Nottingham, UK Salivary Metabolites on Oral Perception 2018 International Society of Clinical Poster: The Origin of Salivary Metabolites: Spectroscopy, Glasgow, UK 1H-NMR Spectroscopy of Multiple Biofluids 2017 European Saliva Symposium, Oral: Correlation between fungiform Egmond aan Zee, Netherlands papillae density and tastant-stimulated salivary compositional change 2017 London Oral Biology Club, Oral: Mechanisms for the oral perception of London, UK astringency 2017 Royal Society of Chemistry Oral and poster: Developing and NMR Discussion Group Standardising a Protocol for Quantitative Postgraduate Meeting, Proton Nuclear Magnetic Resonance (1H- Glasgow, UK NMR) Spectroscopy of Saliva 4 Acknowledgements Completion of this work was only possible thanks to the input of an extensive list of individuals. Firstly, sincere thanks must go to my supervisors, Prof. Guy Carpenter and Dr. Po- Wah So for their constant support and encouragement. I have gotten far more out of this PhD experience than I could have ever imagined. I also express thanks to my industrial supervisor, Dr. Martin Walker,
Recommended publications
  • The Metabolism of Subcutaneous Adipose Tissue in the Immediate Postnatal Period of Human Newborns
    Pediat. Res. 6: 211-218 (1972) Adipose tissue glucose metabolism /3-hydroxyacyl-CoA dehydrogenase neonates fatty acid catabolism phosphofructokinase The Metabolism of Subcutaneous Adipose Tissue in the Immediate Postnatal Period of Human Newborns. 2. Developmental Changes in the Metabolism of 14C-(U)-D-Glucose and in Enzyme Activities of Phosphofructo- kinase (PFK; EC. 2.7.1.11) and /3-Hydroxyacyl-CoA Dehydro- genase (HAD; EC. 1.1.1.35) M. NOVAK1351, E. MONKUS, H. WOLF, AND U. STAVE Department of Pediatrics, University of Miami School of Medicine, Miami, Florida, USA, Staedtische Kinderklinik, Kassel, West Germany, and Fels Research Institute, Yellow Springs, Ohio, USA Extract Changes in the in vitro metabolism of subcutaneous adipose tissue have been compared in normal human newborns from 2 hr to 2 weeks of age. A group of healthy adult volunteers was also included. Samples were obtained by using a needle biopsy tech- nique. More of the isotope from uC-(U)-D-glucose was incorporated into triglyc- erides (P < 0.05) and also oxidized by suspensions of adipose cells from infants 2-3 hr of age than in older infants (P < 0.01). The ratio of radioactivity in carbon dioxide to radioactivity in triglyceride was also significantly greater in 2- to 3-hr-old infants than in older neonates (P < 0.05). Thin layer chromatography of the total lipid ex- tract showed the greatest amount of radioactivity in the triglycerides, a small amount in 1,3-digiycerides and 1,2-diglycerides, and a trace in fatty acids and monogiyc- erides. These findings were compared with the developmental changes in two key enzymes: phosphofructokinase (PFK), which represents the glycolytic pathway, and (3-hydroxyacyl-coenzyme A (GoA) dehydrogenase (HAD), which is involved in the P oxidation of fatty acids.
    [Show full text]
  • Chapter 12 Slides
    11/15/17 CHAPTER 12: Carbohydrates: Structure and Function OUTLINE • 12.1 Role of Carbohydrates • 12.2 Monosaccharides • 12.3 Complex Carbohydrates • 12.4 Carbohydrate Catabolism • 12.5 Oligosaccharides as Cell Markers CHAPTER 12: Carbohydrates: Structure and Function WHAT ARE CARBOHYDRATES? • Glucose and its derivatives are carbohydrates: Ø Carbohydrates are simple organic molecules that have a shared basic chemical Formula: Cn(H2O)n Ø The name “carbo + hydrate” represents that Fact that they are made from CO2 and H2O by photosynthesis • About halF oF all earth’s solid carbon is Found in two polymers of glucose found in plants: Ø Starch = major energy storage molecule Ø Cellulose = major structural component oF the plant cell wall (aka. “fiber”) CHAPTER 12: Carbohydrates: Structure and Function THE SIMPLEST CARBOHYDRATES • Monosaccharides are carbohydrates that cannot be hydrolyZed into simpler carbohydrates: Ø These are the Fundamental building blocks For all other carbohydrates (oFten called “simple sugars”) Ø All have Formulas of based on the basic pattern: Cn(H2O)n • Monosaccharides have speciFic Functional groups: 1. An aldehyde OR a ketone (not both!) 2. Several (two or more) alcohol (-OH) groups 1 11/15/17 CHAPTER 12: Carbohydrates: Structure and Function STRUCTURE & NOMENCLATURE OF MONOSACCHARIDES • Monosaccharides are classiFied by two features: 1. Length of their main carbon chain (utilize standard IUPAC naming For # oF carbons) 2. Whether they contain an aldehyde or ketone group • Names always end with –ose • Two common hexoses:
    [Show full text]
  • Aerobic and Nitrate Respiration Routes of Carbohydrate Catabolism in Pseudomonas S Tut Zeri
    AN ABSTRACT OF THE THESIS OF WILLIAM JAN SPANGLER for the Ph. D. in MICROBIOLOGY (Name) (Degree) (Major) thesis is presented Date 7 / `> /q6! Title AEROBIC AND NITRATE RESPIRATION ROUTES OF CAR- BOHYDRATE CATABOLISM IN PSEUDOMONAS STUTZERI Abstract approved ( Major professor) Pseudomonas stutzeri and other denitrifying bacteria are able to grow under anaerobic conditions, using nitrate -oxygen as the terminal hydrogen acceptor, in a manner analagous to classical aerobic respiration with free -molecular oxygen. This rather unique phenomenon is known as nitrate respiration. Nitrate respiration has been studied with respect to the nitrate reducing enzymes and carrier systems involved in the reduction sequence, but very little emphasis has been placed on the metabolic pathways which are associated with nitrate respiration. This study was carried out in an attempt to establish the metabolic pathways operative, both under aerobic con- ditions and during nitrate respiration, in order to determine whether there was any shift of pathways under conditions of nitrate respira- tion. Primary pathways were determined by the radiorespirometric method using specifically labelled glucose and gluconate. The results, based primarily on the rate of decarboxylation of the C -1 and C -4 positions of glucose, indicated the operation of the Entner- Doudoroff and pentose phosphate pathways under both aerobic condi- tions and conditions of nitrate respiration. Evolution of 14CO2 from the other labels of glucose, as well as incorporation of these labels into the cell, indicated that terminal pathways such as the tricar- boxylic acid cycle or glyoxalate cycle might also be operative under both conditions of oxygen relationship. The secondary pathways were studied using specifically labelled acetate.
    [Show full text]
  • Specific Catabolic Pathways
    Chemistry 1506 Dr. Hunter’s Class Section 12 Notes - Page 1 Chemistry 1506: Allied Health Chemistry 2 Section 12: Specific Catabolic Pathways Molecular Destruction Outline SECTION 12.1 GENERAL FLOW OF CATABOLIC PATHWAYS..............................................................2 SECTION 12.2 GLYCOLYSIS ............................................................................................................................6 SECTION 12.3 TRIGLYCERIDE METABOLISM ..........................................................................................7 2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University Chemistry 1506 Dr. Hunter’s Class Section 12 Notes - Page 2 Section 12.1 General Flow of Catabolic Pathways Overall Process Start with complex mixtures of food molecules Used to generate energy (as “fuel” molecules) ATP NADH and FADH2 Acetyl CoA Ultimate products are CO2, H2O, Urea (C(O)(NH2)2), etc. Intermediate Breakdown products may be used in Anabolic pathways 2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University Chemistry 1506 Dr. Hunter’s Class Section 12 Notes - Page 3 Carbohydrate Catabolism 1st stages can start in the digestive tract Final stage is called glycolysis and finishes within the mitochondrion Polysaccharides ⇓ Oligosaccharides ⇓ Disaccharides ⇓ Monosaccharides ⇓ CO2 + “fuel” molecules 2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University Chemistry 1506 Dr. Hunter’s Class Section 12 Notes - Page 4 Lipid Catabolism Starts in digestive system and ends inside mitochondria Lipases break the ester linkages in the triglycerides Triglycerides ⇓ Glycerol + Fatty Acids ⇓ ⇓ CO2 + “fuel” molecules 2000-2002, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University Chemistry 1506 Dr. Hunter’s Class Section 12 Notes - Page 5 Protein Catabolism Starts in digestive system and ends inside mitochondria Proteins ⇓ Peptides ⇓ Amino Acids ⇓ CO2 + “fuel” molecules + Urea 2000-2002, Dr.
    [Show full text]
  • Nutritional Determinants of Metabolic Diseases in Humans
    Unicentre CH-1015 Lausanne http://serval.unil.ch Year : 2019 NUTRITIONAL DETERMINANTS OF METABOLIC DISEASES IN HUMANS Surowska Anna Surowska Anna, 2019, NUTRITIONAL DETERMINANTS OF METABOLIC DISEASES IN HUMANS Originally published at : Thesis, University of Lausanne Posted at the University of Lausanne Open Archive http://serval.unil.ch Document URN : urn:nbn:ch:serval-BIB_635D730749F67 Droits d’auteur L'Université de Lausanne attire expressément l'attention des utilisateurs sur le fait que tous les documents publiés dans l'Archive SERVAL sont protégés par le droit d'auteur, conformément à la loi fédérale sur le droit d'auteur et les droits voisins (LDA). A ce titre, il est indispensable d'obtenir le consentement préalable de l'auteur et/ou de l’éditeur avant toute utilisation d'une oeuvre ou d'une partie d'une oeuvre ne relevant pas d'une utilisation à des fins personnelles au sens de la LDA (art. 19, al. 1 lettre a). A défaut, tout contrevenant s'expose aux sanctions prévues par cette loi. Nous déclinons toute responsabilité en la matière. Copyright The University of Lausanne expressly draws the attention of users to the fact that all documents published in the SERVAL Archive are protected by copyright in accordance with federal law on copyright and similar rights (LDA). Accordingly it is indispensable to obtain prior consent from the author and/or publisher before any use of a work or part of a work for purposes other than personal use within the meaning of LDA (art. 19, para. 1 letter a). Failure to do so will expose offenders to the sanctions laid down by this law.
    [Show full text]
  • Energy Production in a Cell (Chapter 25 Metabolism)
    Energy Production In A Cell (Chapter 25 Metabolism) Large food molecules contain a lot of potential energy in the form of chemical bonds but it requires a lot of work to liberate the energy. Cells need a quick easy way to get energy for anabolism: this is done with ATP. ATP is an unstable molecule, the bonds of which are easy to break making it a useful source of energy for cells. ATP → ADP + P + free energy from food Food energy + ADP + P → ATP Catabolic reactions generate energy to make ATP, and the ATP energy is used to drive anabolic reactions, such as metabolic turnover (replacement of cell parts), growth and cell division, and special functions (such as secretion, absorption, contraction, or signaling). Metabolism = the sum of all chemical reactions in the body; catabolism + anabolism All energy production begins in the cytosol of the cell. Large molecules are catabolized into smaller molecules, but very little energy is produced: Proteins → amino acids Triglycerides → fatty acids and glycerol Carbohydrates → short carbon chains These smaller molecules are then absorbed and processed in reactions inside the mitochondria. 40% of the energy is captured to produce ATP from ADP and the remaining 60% escapes as heat (used to maintain body temperature). Oxidation-Reduction Reactions (Redox Rxns) Oxidation = the removal of electrons (or addition of oxygen) Reduction = the addition of electrons These reactions are always coupled: one molecule must be oxidized while another is reduced. A-e’ + B → A + B-e’ (A is oxidized while B is reduced) The reduced molecule gains energy while the oxidized molecule loses energy.
    [Show full text]
  • Insights Into the Hexose Liver Metabolism—Glucose Versus Fructose
    Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2017 Insights into the Hexose Liver Metabolism-Glucose versus Fructose Geidl-Flueck, Bettina ; Gerber, Philipp A Abstract: High-fructose intake in healthy men is associated with characteristics of metabolic syndrome. Extensive knowledge exists about the differences between hepatic fructose and glucose metabolism and fructose-specific mechanisms favoring the development of metabolic disturbances. Nevertheless, the causal relationship between fructose consumption and metabolic alterations is still debated. Multiple effects of fructose on hepatic metabolism are attributed to the fact that the liver represents the major sink of fructose. Fructose, as a lipogenic substrate and potent inducer of lipogenic enzyme expression, enhances fatty acid synthesis. Consequently, increased hepatic diacylglycerols (DAG) are thought to directly interfere with insulin signaling. However, independently of this effect, fructose may also counteract insulin-mediated effects on liver metabolism by a range of mechanisms. It may drive gluconeogenesis not only as a gluconeogenic substrate, but also as a potent inducer of carbohydrate responsive element binding protein (ChREBP), which induces the expression of lipogenic enzymes as well as gluconeogenic enzymes. It remains a challenge to determine the relative contributions of the impact of fructose on hepatic transcriptome, proteome and allosterome changes and consequently on the regulation of plasma glucose metabolism/homeostasis. Mathematical models exist modeling hepatic glucose metabolism. Fu- ture models should not only consider the hepatic adjustments of enzyme abundances and activities in response to changing plasma glucose and insulin/glucagon concentrations, but also to varying fructose concentrations for defining the role of fructose in the hepatic control of plasma glucose homeostasis.
    [Show full text]
  • De Novo Lipogenesis in the Liver in Health and Disease: More Than Just a Shunting Yard for Glucose
    Biol. Rev. (2016), 91, pp. 452–468. 452 doi: 10.1111/brv.12178 De novo lipogenesis in the liver in health and disease: more than just a shunting yard for glucose Francis W. B. Sanders1,2 and Julian L. Griffin1,2,∗ 1MRC Human Nutrition Research, Elsie Widdowson Laboratory, 120 Fulbourn Road, Cambridge CB1 9NL, U.K. 2The Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, U.K. ABSTRACT Hepatic de novo lipogenesis (DNL) is the biochemical process of synthesising fatty acids from acetyl-CoA subunits that are produced from a number of different pathways within the cell, most commonly carbohydrate catabolism. In addition to glucose which most commonly supplies carbon units for DNL, fructose is also a profoundly lipogenic substrate that can drive DNL, important when considering the increasing use of fructose in corn syrup as a sweetener. In the context of disease, DNL is thought to contribute to the pathogenesis of non-alcoholic fatty liver disease, a common condition often associated with the metabolic syndrome and consequent insulin resistance. Whether DNL plays a significant role in the pathogenesis of insulin resistance is yet to be fully elucidated, but it may be that the prevalent products of this synthetic process induce some aspect of hepatic insulin resistance. Key words: de novo lipogenesis (DNL), non-alcoholic fatty liver disease (NAFLD), fructose, liver, selective insulin resistance. CONTENTS I. Introduction .............................................................................................
    [Show full text]
  • Anaerobic Pathways Glycolysis Alternate Endpoints Gluconeogenesis
    2/25/2015 Anaerobic Pathways Glycolysis • Lactate – common animal endpoint • Glycolysis – not a waste product – Glucose + 2 ATP → 4 ATP + 2 Pyruvate • No oxygen required • Fairly low energy yield • Lactate byproduct – Resting levels low – Tolerances 40 mmole/kg in humans, 200 mmole/kg in sea turtles – One alternative endpoint is Alanine. During strenuous exercise levels highest in muscle What organism uses that? When? and liver tissue Alternate Endpoints Gluconeogenesis – fate of end products • Lactate transferred to liver, converted back into glucose • Some animals use alternate • Cost of 6 ATP endpoints under some conditions • Why bother? – Goldfish use ethanol in cold, anoxic conditions – Glucose → pyruvate → acetalaldehyde → ethanol – Ethanol is excreted 1 2/25/2015 Review of some terms • Catabolic processes – Glycolysis – Glycogenolysis • Anabolic processes – Glycogenesis – Gluconeogenesis • Molecules – Glucose • Source and storage of glucose – Glucagon • Glycogen – glucose polymer – Pyruvate – Lactate – Hormone control: – Creatine phosphate – Insulin - stimulates storage of glucose in glycogen • Hormones How does the Atkins diet “work”? – Glucagon – reverse (glycogenolysis) – Insulin – Glucagon Oxygen in the Atmosphere 2 2/25/2015 Aerobic pathway Electron transfer system • Overview • From Glycolysis, pyruvate – Glucose + 36 ADP + 6 O2 → oxidation and Krebs cycle 2 36 ATP + 6 CO + 6 H2O – 1 glucose → 10 NADH + 2 • Glycolysis yields 2 pyruvate FADH2 • Convert pyruvate into acetyl- CoA (C2) • Krebs cycle • Electrons transferred to
    [Show full text]
  • Lipid and Carbohydrate Metabolism in Caenorhabditis Elegans
    | WORMBOOK METABOLISM, PHYSIOLOGY, AND AGING Lipid and Carbohydrate Metabolism in Caenorhabditis elegans Jennifer L. Watts*,1 and Michael Ristow† *School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164 and †Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology Zurich, 8603 Schwerzenbach-Zurich, Switzerland ORCID ID: 0000-0003-4349-0639 (J.L.W.) ABSTRACT Lipid and carbohydrate metabolism are highly conserved processes that affect nearly all aspects of organismal biology. Caenorhabditis elegans eat bacteria, which consist of lipids, carbohydrates, and proteins that are broken down during digestion into fatty acids, simple sugars, and amino acid precursors. With these nutrients, C. elegans synthesizes a wide range of metabolites that are required for development and behavior. In this review, we outline lipid and carbohydrate structures as well as biosynthesis and breakdown pathways that have been characterized in C. elegans. We bring attention to functional studies using mutant strains that reveal physiological roles for specific lipids and carbohydrates during development, aging, and adaptation to changing environmental conditions. KEYWORDS Caenorhabditis elegans; ascarosides; glucose; fatty acids; phospholipids; sphingolipids; triacylglycerols; cholesterol; maradolipids; WormBook TABLE OF CONTENTS Abstract 413 Fatty Acids 415 Characteristics of C. elegans fatty acids 415 Methods
    [Show full text]
  • Glucose Catabolism in Mung Bean (Phaseolus Aureus) Seedlings
    AN ABSTRACT OF THE THESIS OF GEORGE JOJI .IKEDA for the DOCTOR OF PHILOSOPHY (Name) (Degree) in CHEMISTRY presented on May 10, 1967 (Major) (Date) Title: GLUCOSE CATABOLISM IN MUNG BEAN (PHASEOLUS AUREUS) SEEDLINGS Redacted for Privacy Abstract approved: Dr. C. H. Wang Little is known regarding the catabolic mechanisms involved in the breakdown of glucose in mung bean (Phaseolus aureus) seedlings. Studies in other laboratories have shown that the TCA cycle pathway is operative in mung bean leaves, and have demon- strated the presence of enzymes for the oxidation of glucose to glucuronic acid in mung bean seedlings. In the present study, the primary pathways responsible for the catabolism of glucose in detached 10 -13 day old mung bean shoots were identified and the relative participation of each of these pathways was estimated. The radiorespirometric method was employed for these experi- ments, using an ion chamber - electrometer system to monitor the respiratory 14CO2 evolved from detached mung bean shoots catabolizing 14C- labeled glucose substrates in the dark. Substrates were administered in two different ways, i.e., by means of a one- dose method and a continuous feeding method. The one -dose experiments gave rise to respiratory 14CO2 yield data which were used to estimate the relative pathway contributions. With the con- tinuous feeding experiments, a metabolic steady state with regard 14CO2 to glucose utilization was realized, and the data on production enabled one to calculate the catabolic rates of the individual glucose pathways. Comparison of the relative rates also provided one with information on the relative participation of glucose pathways.
    [Show full text]
  • Biological Sciences
    A Comprehensive Book on Environmentalism Table of Contents Chapter 1 - Introduction to Environmentalism Chapter 2 - Environmental Movement Chapter 3 - Conservation Movement Chapter 4 - Green Politics Chapter 5 - Environmental Movement in the United States Chapter 6 - Environmental Movement in New Zealand & Australia Chapter 7 - Free-Market Environmentalism Chapter 8 - Evangelical Environmentalism Chapter 9 -WT Timeline of History of Environmentalism _____________________ WORLD TECHNOLOGIES _____________________ A Comprehensive Book on Enzymes Table of Contents Chapter 1 - Introduction to Enzyme Chapter 2 - Cofactors Chapter 3 - Enzyme Kinetics Chapter 4 - Enzyme Inhibitor Chapter 5 - Enzymes Assay and Substrate WT _____________________ WORLD TECHNOLOGIES _____________________ A Comprehensive Introduction to Bioenergy Table of Contents Chapter 1 - Bioenergy Chapter 2 - Biomass Chapter 3 - Bioconversion of Biomass to Mixed Alcohol Fuels Chapter 4 - Thermal Depolymerization Chapter 5 - Wood Fuel Chapter 6 - Biomass Heating System Chapter 7 - Vegetable Oil Fuel Chapter 8 - Methanol Fuel Chapter 9 - Cellulosic Ethanol Chapter 10 - Butanol Fuel Chapter 11 - Algae Fuel Chapter 12 - Waste-to-energy and Renewable Fuels Chapter 13 WT- Food vs. Fuel _____________________ WORLD TECHNOLOGIES _____________________ A Comprehensive Introduction to Botany Table of Contents Chapter 1 - Botany Chapter 2 - History of Botany Chapter 3 - Paleobotany Chapter 4 - Flora Chapter 5 - Adventitiousness and Ampelography Chapter 6 - Chimera (Plant) and Evergreen Chapter
    [Show full text]