Oxygen consumption in burrowed and unburrowed ammocoetes of Lampetra planeri (Bloch).
Abstract 1. 1. At 15°C, the attainment of a constant rate of oxygen consumption took up to approximately 3 hr in burrowed and 12 hr in unburrowed ammocoetes. 2. 2. The rate in acclimated ammocoetes (mean wet wt. l·34g) burrowed in the light and dark was 41·7 and 40·1 μl/g per hr respectively and in unburrowed animals under the same regimes was 69·0 and 55·7 μl/g per hr. 3. 3. These results clarify conflicting previous recordings and indicate that ammocoetes have a very low metabolic rate.
Oxygen consumption by ammocoetes of the lampreyGeotria australis in air
When covered by moistened lint-free gauze, the larvae (ammocoetes) of the lampreyGeotria australis survived, without apparent discomfort, for 4 days in water-saturated air at 10, 15 and 20°C. In air, the mean standard rates of O2 consumption of medium to large ammocoetes ofG. australis (000000000;=0.52 g) at 10, 15 and 20°C were 14.5, 35.7 and 52.1 μl·g−1·h−1, respectively. At 15°C, the slope of the relationship between log O2 consumption (μlO2·h−1) and log body weight for ammocoetes over a wide range in body weight was 0.987. TheQ10s for rate of O2 consumption between 10 and 15°C, 15 and 20°C and 10 and 20°C were 4.9, 2.9 and 3.6, respectively. Our results and observations of the ammocoetes suggest that, when out of water, larvalG. australis derives most of its O2 requirements from cutaneous respiration, particularly at lower temperatures. This would be facilitated by the small size and elongate shape (and thus a relatively high surface-to-volume ratio), low metabolic rate, thin dermis, extensive subdermal capillary network and high haemoglobin concentration of larvalG. australis.
Microfiltration: Effect of retentate protein concentration on limiting flux and serum protein removal with 4-mm-channel ceramic microfiltration membranes.
The objective of our study was to determine if the limiting flux and serum protein (SP) removal were different at 8, 9, or 10% true protein (TP) in the microfiltration (MF) retentate recirculation loop using 0.1-µm ceramic graded permeability membranes with 4-mm-channel diameters operated at 50 °C using a diluted milk protein concentrate with 85% protein on a total solids basis (MPC85) as the MF feed. The limiting flux for the MF of diluted MPC85 was determined at 3 TP concentrations in the recirculation loop (8, 9, and 10%). The experiment was replicated 3 times for a total of 9 runs. On the morning of each run, MPC85 was diluted with reverse osmosis water to an MF feed TP concentration of 5.4%. In all runs, the starting flux was 55 kg/m(2) per hour, the flux was increased in steps until the limiting flux was reached. The minimum flux increase was 10 kg/m(2) per hour. The limiting flux decreased as TP concentration in the recirculation loop increased. The limiting flux was 154 ± 0.3, 133 ± 0.7, and 117 ± 3.3 kg/m(2) per hour at recirculation loop TP concentrations of 8.2 ± 0.07, 9.2 ± 0.04, and 10.2 ± 0.09%, respectively. No effect of recirculation loop TP concentration on the SP removal factor was detected. However, the SP removal factor decreased from 0.80 ± 0.02 to 0.75 ± 0.02 as flux was increased from the starting flux of 55 kg/m(2) per hour to the limiting flux, with a similar decrease seen at all recirculation loop TP concentrations.