. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. METABOLISM OF SPONGE GEMMULES 387 taining a nominally oxygen-free status in the flow- through system (for methodological precautions em- ployed, see Gnaiger 1983a; Hand and Gnaiger, 1988; Hand, 1990), evidence indicates that a sealed ampoule system, while experimentally cumbersome in terms of reversibility, may be slightly more effective in providing an anoxic environment (Hand, 1995). The influence of antibiotics (50 mg/1 each of penicillin and streptomycin) on the heat dissipation was evaluated by exposing gemmules for 5 h
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. METABOLISM OF SPONGE GEMMULES 387 taining a nominally oxygen-free status in the flow- through system (for methodological precautions em- ployed, see Gnaiger 1983a; Hand and Gnaiger, 1988; Hand, 1990), evidence indicates that a sealed ampoule system, while experimentally cumbersome in terms of reversibility, may be slightly more effective in providing an anoxic environment (Hand, 1995). The influence of antibiotics (50 mg/1 each of penicillin and streptomycin) on the heat dissipation was evaluated by exposing gemmules for 5 h to perfusion with nitro- gen-saturated medium and then switching to the same nitrogen-saturated medium containing antibiotics. The slope of the iiW-versus-time curve before the switch to antibiotics was compared to the slope 4 h after the switch. The slopes were not significantly different (P = , n = 3, paired, two-tailed / test). Similarly, the ab- solute jiW values before and after the switch were not significantly different (P = , n = 3, paired, two- tailed t test). Thus, antibiotics were not included in the water used for calorespirometry experiments. A denylate measurements Post-diapause gemmules were incubated aerobically in stream water at 20°-23°C. At the indicated time points, triplicate samples were extracted with perchloric acid (Rees and Hand, 1991). Perchloric acid precipitates were resuspended in TV NaOH and assayed for total protein with a modified Lowry assay (Peterson, 1977). The neutralized supernatants were analyzed for adenyl- ates by high-performance liquid chromatography using weak anion exchange as previously described (Rees and Hand, 1991). Briefly, the separation column of amino propyl silica (250 X mm, 5 ^m particle size; Pheno- menex, Torrance, CA) was eluted isocratically with a 2:1 mixture of acetonitrile and 60 mA/potassium phosphate buffer (pH ). The potassium phosphate replaced the ammonium bicarbonate used by Rees and Han
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
