Two separate experiments were conducted to determine the dietary requirements of juvenile Asian sea bass Lates calcarifer Bloch for lysine and arginine. Fish (average initial weight: lysine experiment, 13.12 ± 0.12 g; arginine experiment, 2.56 ± 0.13 g) were given amino acid test diets for 12 weeks containing fish meal, zein, squid meal, and crystalline amino acids. Each set of isonitrogenous and isocaloric test diets contained graded levels of L‐lysine or L‐arginine. The feeding rate in the lysine experiment was at 4–2.5% of the body weight day−1, while in the arginine experiment it was at 10–4% of the body weight day−1. The fish (20 per tank, lysine experiment; 15 per tank, arginine experiment) were reared in 500‐L fibreglass tanks with continuous flowthrough sea water at 27 °C and salinity of 31 ppt in the lysine experiment and at 29 °C and salinity of 29 ppt in the arginine experiment. The experiments were in a completely randomized design with two replicates per treatment. Survival was high in fish given adequate lysine or arginine. Mean percentage weight gains were significantly different in fish fed varying levels of lysine or arginine. Fish fed high levels of L‐arginine suffered high mortalities. No significant differences were obtained in the feed efficiency ratios (FER, g gain g−1 feed) of fish fed graded lysine, although the values tended to increase as the dietary lysine level was increased up to the requirement level. In contrast, in the arginine experiment, significant differences in FER of fish among treatments were obtained; the highest FER was observed in fish fed the diet containing an optimum arginine level. On the basis of the growth response, survival, and FER, the lysine and arginine requirements of juvenile Asian sea bass were estimated to be 20.6 g kg−1 dry diet (4.5% protein) and 18.2 g kg−1 dry diet (3.8% protein), respectively. These data will be useful in the further refinement of practical diet formulations for the Asian sea bass.

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Excitation-transcription coupling, namely the process whereby plasma membrane depolarization leads to gene activation or inactivation, is still a black box for most muscle genes. Muscle regeneration is a useful model system to ask basic questions concerning the triggering signals and the transduction pathways involved in activity-dependent gene regulation. We report ongoing research in our laboratory concerning (1) myosin heavy chain changes in regenerating muscle in the presence and absence of the nerve, as well as changes induced by electrical stimulation, (2) identification of activity response elements in the promoter of a slow myosin light chain gene, and (3) potential approaches to define the transduction pathways induced by neural or electrical activity and implicated in muscle gene regulation.

No abstract

The aim of this paper is the characterization of global erythemal irradiance (UVER) on inclined planes. Different geometric models have been studied, both isotropic and anisotropic, which have been used to estimate the global UVER on inclined planes at 40• in North, South, East and West orientations. This has led to the hypothesis that these models, all of them originally developed to obtain diffuse irradiance in solar spectrum, can be applied in a much more limited range of UVER. The results have been compared with experimental data using the following statistical parameters: mean bias deviation, mean absolute deviation and root mean square deviation. The global UVER was analyzed for all sky conditions and for cloudless sky conditions, and no significant differences were found between the different models in both cases. Overall, the best performing model is Gueymard's anisotropic model, even though it improves the Isotropic model in less than 2%.