Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Tuesday, February 13, 2001, Time: 2:00:00 PM

Location: Aztec

Gorokhova, E, , Arizona State University, Tempe, USA, elenag@imap1.asu.edu

Kyle, M, , Arizona State University, Tempe, USA, mkyle@asu.edu

ANALYSIS OF NUCLEIC ACIDS IN DAPHNIA: DEVELOPMENT OF METHODS AND ONTOGENETIC VARIATIONS IN RNA-DNA CONTENT

Fluorochromes, PicoGreen and RiboGreen (Molecular Probes, Inc.), were used to detect concentrations of nucleic acids (RNA and DNA) in individual Daphnia in all developmental stages. Nucleic acids were extracted in N-laurosarcosyl and assayed by fluorescence using (1) RiboGreen (non-specific dye) and PicoGreen (DNA-specific dye) and (2) RiboGreen alone with and without RNase. The two methods yield similar values for DNA and RNA. The second method allows determination of RNA and DNA using a single sample (modified from Bentle et al., Analyt. Biochem., 1981). In parthenogenically reproducing Daphnia pulex, RNA and DNA concentrations related to changes in metabolic activity associated with ontogenetic development. RNA concentration peaked at the latest stages of embryonic development and neonates, followed by a gradual decline (lowest values in adult females , eggs removed). Similarly, DNA concentrations were highest during the early phase of postnatal development, decreasing when body size increased. Our results suggest that ontogenetic variations have implications for the use of nucleic acids as a measure for growth in zooplankton and may provide insights into mechanisms of cellular growth (cell multiplication and cell enlargement).

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Aquatic Sciences Meeting, Albuquerque 2001

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