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On Rana Pipiens Metamorphosis and Development UNLV Theses, Dissertations, Professional Papers, and Capstones 2004 The Effects of environmentally relevant doses of Perchlorate (ClO4-) on Rana Pipiens metamorphosis and development Andrea N. Golli University of Nevada Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Desert Ecology Commons, Environmental Indicators and Impact Assessment Commons, and the Zoology Commons Repository Citation Golli, Andrea N., "The Effects of environmentally relevant doses of Perchlorate (ClO4-) on Rana Pipiens metamorphosis and development" (2004). UNLV Theses, Dissertations, Professional Papers, and Capstones. 183. http://dx.doi.org/10.34917/1436436 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. THE EFFECTS OF ENVIRONMENTALLY RELEVANT DOSES - OF PERCHLORATE (ClO4 ) ON RANA PIPIENS METAMORPHOSIS AND DEVELOPMENT by Andrea N. Golli Bachelor of Science University of Findlay 2001 Master of Science University of Nevada, Las Vegas 2004 A thesis submitted in partial fulfillment of the requirements for the Master of Science Degree in Environmental Science Department of Environmental Studies Greenspun College of Urban Affairs Graduate College University of Nevada, Las Vegas May 2004 ABSTRACT The Effects of Environmentally Relevant Doses - of Perchlorate (ClO4 ) on Rana pipiens Metamorphosis and Development by Andrea N. Golli Dr. Shawn Gerstenberger, Examination Committee Chair Associate Professor University of Nevada, Las Vegas The purpose of this study was to assess the effects of environmentally relevant concentrations of perchlorate on the development and growth of Rana pipiens. Ammonium perchlorate is a rocket fuel oxidizer that is known to interfere with the function of the thyroid gland and some of the highest United States surface water concentration exists in the Las Vegas Wash, NV. Perchlorate not only blocks the body’s ability to incorporate iodine into T3 and T4 hormones through the sodium iodine symporter system, but also depletes the thyroid glands’ internal stores of iodine. Many of the steps that regulate metamorphosis in amphibians are also triggered by thyroid hormones therefore we investigated the ability of perchlorate to interfere with the development and metamorphosis of Rana pipiens. Aquaria containing concentrations of 40 ppb, 400 ppb, and 4000 ppb perchlorate with a 0 ppb perchlorate control as well as a magnesium control (since magnesium perchlorate was used) to evaluate the growth and development of Rana pipiens. Measuring snout to vent length, hindlimb length, tail iii length and total body length weekly on 40 animals per tank allowed the growth of the tadpoles to be monitored throughout the study. Development of the tadpoles was determined by staging 20 animals per dose group according to the Taylor-Kollros Index. Metabolic rate for each dose group was assessed monthly by determining oxygen consumption; while deformities, as well as mortality, were tracked daily. The magnesium control completed metamorphosis during week 10, followed by the 40 ppb and 4000 ppb groups in week 21 with the control and 400 ppb group completing development during week 33. The magnesium control was larger (tail, snout to vent, total body, hindlimb) than all of the other groups during weeks 2-11. The weight adjusted oxygen consumption provided similar results with the magnesium and control groups consuming more oxygen than the other groups, while the 400 ppb group consistently consumed the least oxygen. Experimental problems significantly reduced the number of animals in 400 ppb, magnesium control and 4000 ppb groups thereby causing resource allocation problems. The magnesium control group developed faster than all other groups, which could be due to magnesium’s up-regulation during glycolysis. The increased energy production could be accelerating metamorphosis, and hence attenuating perchlorate’s inhibitory mechanism. Oxygen consumption appears to be a more sensitive biomarker, and is useful for detecting alterations prior to seeing adverse effects on growth and development. The concentrations of perchlorate used in this study did not delay development or metamorphosis in Rana pipiens. iv TABLE OF CONTENTS ABSTRACT.......................................................................................................................iii LIST OF FIGURES .......................................................................................................... vii LIST OF TABLES...........................................................................................................viii ACKNOWLEDGEMENTS............................................................................................... ix CHAPTER 1 INTRODUCTION ....................................................................................... 1 Purpose of the Study ........................................................................................................... 2 CHAPTER 2 LITERATURE REVIEW ............................................................................ 3 Chemical Forms and Properties.......................................................................................... 8 Biotransformation ............................................................................................................. 10 Distribution ....................................................................................................................... 11 Thyroid Hormone System................................................................................................. 11 Hormonal Action .................................................................................................. 14 Control of Thyroid Hormone Secretion................................................................ 16 Effects of Thyroid Hormones ............................................................................... 18 Mechanism of Perchlorate Action .................................................................................... 19 Effects of Thyroid Dysfunction ........................................................................................ 21 Biomarkers........................................................................................................................ 26 Human Exposure Studies...................................................................................... 26 Mammalian Research............................................................................................ 29 Amphibian Research............................................................................................. 33 Amphibian Life-cycle ....................................................................................................... 37 Taylor-Kollros Index ............................................................................................ 37 Premetamorphosis, Prometamorphosis and Metamorphic Climax....................... 39 Hormone Regulation............................................................................................. 41 Environmental Factors.......................................................................................... 42 Two Theories on the Controlling Mechanism ...................................................... 43 Declining Amphibian Populations.................................................................................... 47 CHAPTER 3 METHODS AND MATERIALS .............................................................. 52 Preliminary Study: Las Vegas Wash Water...................................................................... 53 Animals................................................................................................................. 53 Water Collection and Water Analysis................................................................... 54 v Oxygen Analyzer .................................................................................................. 56 Developmental Assessment .................................................................................. 57 Secondary Study: Laboratory Mixed Perchlorate Water.................................................. 59 Animals................................................................................................................. 60 Water Collection and Water Analysis................................................................... 60 Oxygen Analyzer .................................................................................................. 61 Developmental Assessment .................................................................................. 62 CHAPTER 4 RESULTS Preliminary Study: Las Vegas Wash Water...................................................................... 64 Secondary Study: Laboratory Mixed Perchlorate Water.................................................. 65 Survival ...............................................................................................................
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