. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. UPTAKE BY AXENIC U. CAUPO LARVAE 321 in the free amino acid pools oflarvae was observed using two-dimensional thin-layer chromatography (Jones and Heathcote, 1966) of ethanol extracts (75%, v/v). An ali- quot of the extract (2 /ul) was spotted onto a 10 cm X 10 cm cellulose plate ( mm thick, EM Science Brand) and the radioactivity visualized after exposure to X-ray film (XOMAT AR, Eastman-Kodak Co.). Metabolic rates oflarvae Oxygen consumption was measured using a Clark- type polarographic oxygen electrode system, consist
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. UPTAKE BY AXENIC U. CAUPO LARVAE 321 in the free amino acid pools oflarvae was observed using two-dimensional thin-layer chromatography (Jones and Heathcote, 1966) of ethanol extracts (75%, v/v). An ali- quot of the extract (2 /ul) was spotted onto a 10 cm X 10 cm cellulose plate ( mm thick, EM Science Brand) and the radioactivity visualized after exposure to X-ray film (XOMAT AR, Eastman-Kodak Co.). Metabolic rates oflarvae Oxygen consumption was measured using a Clark- type polarographic oxygen electrode system, consisting of a Strathkelvin Instruments oxygen meter (Model 781), a micro-electrode (#1302), and a microrespiration chamber (RC200). The respiration chamber was cali- brated to 100 ^1 total volume and maintained at 15°C ± °C by a water bath (Model RDL 20, Precision In- struments). Prior to experiments, the stability and self- consumption rate of the electrode were determined in isothermal seawater. After a 2-min equilibration period, following the addition of larvae, the change in oxygen tension (mm Hg) within the respiration chamber was re- corded every min for at least 21 min. At the completion of each experiment (n > 3), the larvae were removed and counted (ca. 100 to 200 per experiment). The electrode was calibrated to zero oxygen tension by deoxygenating seawater with excess sodium thiosulfite or sodium sultite. Calibration of the meter reading (mm Hg) with molar oxygen concentration was made by measuring the oxy- gen tension in a 300-ml BOD bottle filled with isother- mal seawater, and then chemically determining the mo- lar oxygen concentration using the Winkler titration method (Parsons el al, 1984). Results Cnlturing the larvae of Urechis caupo under axenic conditions Aseptic removal of mature gametes from Urechis caupo. and subsequent fertilization, yielded axenic lar- vae. Approximately 80% of the cultures produced in this manner tested negative for the presence
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
