A study of copper and copper proteins in the eggs of <i>Sepia officinalis</i> L.

1. Eggs from Sepia officinalis L. contain a high amount of copper (109 fxg/g dry weight ). The water soluble extracts of these eggs have been studied. The copper content of the extracts at different pH-values were determined with an atomic absorption spectrophotometer and with the bathocuproin sulphonate method. The proteins in the different extracts were studied by electrophoretic techniques.2. The extracted egg proteins were difficult to handle. They have a high molecular weight and show no migration after electrophoresis in 6 % acrylamide gels.3. Fragmentation of the extracted egg proteins has been effectuated by enzymatic treatment followed by the addition of 8M uruem, and by alkaline hydrolysis. Only the latter procedure resulted in electrophoretically migrating copper containing protein fragments.4. After SDS electrophoresis of the copper containing protein fragments, relative molecular masses (Mr) of 3800, 8600, 17800, 35300 and 132000 were observed

Effect of hydrogen ions and inorganic complexing on the uptake of copper by the brine shrimp <i>Artemia franciscana</i>

The effect of hydrogen ions and inorganic complexing on copper uptake in the brine shrimp Artemia franciscana has been studied in chemically defined saltwater solutions. Uptake increases with decreasing hydrogen ion concentration and decreases with increasing carbonate complexation. A simple non-linear model that combines the effect of hydrogen ions on the transport of the metal across the solution-body interface and the effect of hydrogen ions and complexation on the speciation of the metal provided a close functional description of the observed variation in copper uptake by brine shrimp

Determination of copper in embryos and very young specimens of <i>Sepia officinalis</i>

The total amount of copper in embryos and newly hatched young individuals of Sepia officinalis L. has been determined by microtechnique, using bathocuproine-sulfonate as complexing reagent. During embryonic life, the total amount of copper does not change; it remains at a level close to 3.8 µg. The copper is found in the yolk sac of very early embryos; it is subsequently transferred into the embryo proper. After hatching, the copper content diminishes quickly in starved individuals. Fed S. officinalis also usually lose copper. The reason for this may be that the inner yolk sac of newly hatched individuals contains a great deal of the total copper, which is excreted with the yolk after the latter has become superfluous. Later on, copper must be taken up from the food. The mobilization of protein and copper from the yolk into the blood may account for the early appearance of embryonic hemocyanin in the blood

Respiration of Sepia officinalis during embryonic and early juvenile life

Adult Sepia officinalis L. were caught in June 1984, in the coastal waters of Wimereux (France). Deposition of the eggs took place in the seawater aquaria of the “Station Marine”. The oxygen consumption of S. officinalis was measured during embryonic and juvenile development. Aerobic metabolism occurs as soon as the early embryonic Stage 21. Oxygen diffuses through the initially thick egg shell; the oxygen level in the perivitelline liquid reaches a maximal value just before hatching (116.7±6.9 mm Hg). Hatchings display only a slight increase in oxygen consumption compared to embryos in the last stage of development. Respiration experiments with 40 d old juveniles showed that oxygen consumption increases with temperature, but is not affected by photoperiod. Experiments under increasing hypoxia revealed that S. officinalis juveniles are good regulators and maintain a constant oxygen consumption in the range of 4 to 7 mg O2l-1. Juveniles successfully recover from an hypoxic stress of 2 mg O2l-1 maintained for 1 h. This suggests that the respiratory pigments (pre-hemocyanins) of 40 d-old juveniles have a high oxygen affinity and/or that these juveniles have the ability to adapt to anaerobic conditions

HERschel Observations of Edge-on Spirals (HEROES). IV. Dust energy balance problem

We present results of the detailed dust energy balance study for the seven large edge-on galaxies in the HEROES sample using 3D radiative transfer (RT) modelling. Based on available optical and near-infrared observations of the HEROES galaxies, we derive the 3D distribution of stars and dust in these galaxies. For the sake of uniformity, we apply the same technique to retrieve galaxy properties for the entire sample: we use a stellar model consisting of a S\'ersic bulge and three double-exponential discs (a superthin disc for a young stellar population and thin and thick discs for old populations). For the dust component, we adopt a double-exponential disc with the new THEMIS dust-grain model. We fit oligochromatic radiative transfer (RT) models to the optical and near-infrared images with the fitting algorithm FitSKIRT and do panchromatic simulations with the SKIRT code at wavelengths ranging from ultraviolet to submillimeter. We confirm the previously stated dust energy balance problem in galaxies: for the HEROES galaxies, the dust emission derived from our RT calculations underestimates the real observations by a factor 1.5-4 for all galaxies except NGC 973 and NGC 5907 (apparently, the latter galaxy has a more complex geometry than we used). The comparison between our RT simulations and the observations at mid-infrared-submillimeter wavelengths shows that most of our galaxies exhibit complex dust morphologies (possible spiral arms, star-forming regions, more extended dust structure in the radial and vertical directions). We suggest that, in agreement with the results from Saftly et al. (2015), the large- and small-scale structure is the most probable explanation for the dust energy balance problem.Comment: 53 pages, 31 figures, Accepted for publication in Astronomy & Astrophysic