title: Tetrodotoxin concentrations within a clutch and across embryonic development in eggs of the rough-skinned newts (Taricha granulosa).
abstract: Tetrodotoxin is an enigmatic neurotoxin that is found in a wide-variety of organisms. Unfortunately, tetrodotoxin (TTX) toxicity across life-history stages is poorly understood in most organisms. Rough-skinned newts (Taricha granulosa) possess the greatest known quantities of TTX of any organism and numerous studies have begun to elucidate these patterns in this species. We conducted a series of studies to answer the following questions: (1) do eggs from a single female's clutch vary in toxicity? (2) does TTX concentration change during embryonic development? and (3) does the jelly coat from newt eggs possess TTX? We found that the amount of TTX in newt eggs depended on the relative "position" of the egg within a clutch; eggs deposited at the beginning of the clutch had substantially more TTX than those at the end. During development egg toxicity remained consistent until hatching. The jelly coat contained small quantities of TTX, but these were not correlated with the toxicity of the embryo. These results clarify several long-held interpretations about embryo toxicity and continue to elucidate the life-history patterns of tetrodotoxin toxicity in this amphibian.
authors.affiliation: Department of Biology, Hanover College, P. O. Box 108, Hanover, IN, 47243, USA. Electronic address: gall@hanover.edu.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Gall
authors.affiliation: Department of Biology, California State University, 9001 Stockdale Highway, Bakersfield, CA, 93311, USA.
authors.forename: Amber N
authors.initials: AN
authors.lastname: Stokes
authors.affiliation: Department of Biology, Utah State University, 5305 Old Main HL, Logan, UT, 84322, USA.
authors.forename: Jory J
authors.initials: JJ
authors.lastname: Pett
authors.affiliation: Department of Biology, Hanover College, P. O. Box 108, Hanover, IN, 47243, USA.
authors.forename: Kari L
authors.initials: KL
authors.lastname: Spivey
authors.affiliation: Department of Biology, Utah State University, 5305 Old Main HL, Logan, UT, 84322, USA.
authors.forename: Susannah S
authors.initials: SS
authors.lastname: French
authors.affiliation: Mountain Lake Biological Station and Department of Biology, University of Virginia, P.O. Box 400328, Charlottesville, VA, 22904, USA.
authors.forename: Edmund D
authors.initials: ED
authors.lastname: Brodie
authors.affiliation: Department of Biology, Utah State University, 5305 Old Main HL, Logan, UT, 84322, USA.
authors.forename: Edmund D
authors.initials: ED
authors.lastname: Brodie
mesh_terms: D000818:Animals; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D011247:Pregnancy; D012455:Salamandridae / Q000196:embryology*; D013779:Tetrodotoxin / Q000378:metabolism / Q000633:toxicity*
chemical_list: D013779:Tetrodotoxin
keywords: Egg toxicity; Salamandridae; TTX; Tetrodotoxin