Presentation Title

Nitrogen excretion during marsupial development in a terrestrial isopod.

Faculty Mentor

Jonathan Wright

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 24

Session

Poster 2

Type of Presentation

Poster

Subject Area

behavioral_social_sciences

Abstract

Like their marine counterparts, terrestrial isopods (suborder Oniscidea) have direct, lecithotrophic (yolk-fed) development and the embryos are brooded in a fluid-filled ventral marsupium. In this study we set out to study metabolites of nitrogen metabolism and how these are either eliminated or stored during marsupial development. Embryos of Armadillidium vulgare were tested for the presence of waste nitrogen in the form of urea, uric acid, ammonia and glutamine throughout development as defined by six stages: early and late stage one (chorionated egg); early and late stage two, demarcated by blastokinesis; mancas (marsupial juveniles); and post-marsupial juveniles. Marsupial fluid volume and ammonia concentration were also measured over the course of development. Stage 1 and Stage 2 embryos are primarily ammonotelic. During the manca stage, ammonia production declines sharply and mancas switch to storage excretion of uric acid. Following release from the marsupium, juveniles revert to ammonotely, eliminating the base (NH3) in gaseous form. Comparing cumulative nitrogen metabolites and measured metabolism of the marsupial stages, we determined that protein metabolism accounts for 18.9% of total catabolism. Glutamine storage excretion increased significantly in juveniles and Gln probably functions as an intermediary nitrogen store between bouts of (diurnal) ammonia volatilization. Marsupial fluid volume remained similar throughout development, about 0.35 μL embryo-1, until the manca stage where it is ingested. Selection to protect against ammonia toxicity during this period may account for the abrupt cessation of ammonia production and use of urate storage excretion during the manca stage.

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Nitrogen excretion during marsupial development in a terrestrial isopod.

BSC-Ursa Minor 24

Like their marine counterparts, terrestrial isopods (suborder Oniscidea) have direct, lecithotrophic (yolk-fed) development and the embryos are brooded in a fluid-filled ventral marsupium. In this study we set out to study metabolites of nitrogen metabolism and how these are either eliminated or stored during marsupial development. Embryos of Armadillidium vulgare were tested for the presence of waste nitrogen in the form of urea, uric acid, ammonia and glutamine throughout development as defined by six stages: early and late stage one (chorionated egg); early and late stage two, demarcated by blastokinesis; mancas (marsupial juveniles); and post-marsupial juveniles. Marsupial fluid volume and ammonia concentration were also measured over the course of development. Stage 1 and Stage 2 embryos are primarily ammonotelic. During the manca stage, ammonia production declines sharply and mancas switch to storage excretion of uric acid. Following release from the marsupium, juveniles revert to ammonotely, eliminating the base (NH3) in gaseous form. Comparing cumulative nitrogen metabolites and measured metabolism of the marsupial stages, we determined that protein metabolism accounts for 18.9% of total catabolism. Glutamine storage excretion increased significantly in juveniles and Gln probably functions as an intermediary nitrogen store between bouts of (diurnal) ammonia volatilization. Marsupial fluid volume remained similar throughout development, about 0.35 μL embryo-1, until the manca stage where it is ingested. Selection to protect against ammonia toxicity during this period may account for the abrupt cessation of ammonia production and use of urate storage excretion during the manca stage.