Analysis of initial fouling process in coastal environment: effects of settlement, attachment, and metamorphosis promoters.

Effects of lumichrome, L-tryptophan, and curcumin on fouling organisms were examined on panels immersed in a near-shore aquatic environment. These products showed effective action in aquariums in preliminary screening tests for promoting different steps of fouling. Lumichrome showed metamorphosis-inducing activity for ascidian larvae (Halocynthia), L-tryptophan was a settlement-inducer for larvae of barnacles (Balanus), and curcumin showed attachment-promoting activity on the blue mussel (Mytilus). In order to establish that these tests are helpful in screening actual fouling or antifouling compounds, we examined the action of these three compounds in a coastal environment by following the first steps of biofouling, that is, by studying the quantity of chlorophyll, the number of bacterial cells, and the larvae settled. These experiments on the seashore indicated that these compounds did not act as promoters for the target organisms; however, they did show promoting effects on some nontarget organisms.

[Variation in the level of free amino acids during larva development of Penaeus japonicus (Crustacea, Decapoda, Penaeidae]. / Variations des concentrations des acides aminés libres au cours du développement larvaire de Penaeus japonicus Bate (Crustacea, Decapoda, Penaeidae).

Variations of free amino-acids (FAA) content during the larval development of Penaeus japonicus have been studied. FAA content increases from 83 to 687 mumoles/g dry weight from egg to post-larval (20 days old: P20) development. There is a sharp increase between zoe and mysis stages, and another one between one day post-larvae (P1) and P20. After the mysis stage, free essential and non essential amino-acids evolve in a different way: the non essential FAA content, mainly glycine, increases continuously, whereas essential FAA content decreases (about 40%) from the mysis stage to metamorphosis in post-larvae (P1). FAA content evolution during larval development exhibits the same trend as the variation of the digestive enzyme activity.

[Circadian variations in hemolymph lipids and lipoproteins and in hepatopancreatic lipids of the shrimp Penaeus japonicus]. / Variations circadiennes des lipides et lipoprotéines de l'hémolymphe, et des lipides de l'hépatopancréas, chez la crevette Penaeus japonicus.

Lipids content of the haemolymph and the hepatopancreas in the decapod Crustacean P. japonicus exhibits a bicircadian rhythm characterized by one maximum in the night and another one during the day. The maximal values in the haemolymph are approximately two and a half times greater (8 mg/ml) than minimal ones (3 mg/ml). Variations are less important in the hepatopancreas. A bicircadian rhythm of lipid classes in the haemolymph is observed very significantly in concentration of polar lipids and free sterols with maximal values (6.87 mg/ml and 0.59 mg/ml) and minimal values (2.63 mg/ml and 0.23 mg/ml) respectively. Polar lipids are the major lipid fractions in the haemolymph (87%). The electrophoretic behaviour of haemolymph lipoproteins is determined.

[Circadian variation in the free fatty acid level of abdominal muscle of Palaemon serratus (Pennant 1777) Crustacea, Decapoda]. / Variations circadiennes de la teneur en acides gras libres du muscle abdominal de Palaemon serratus (Pennant 1777) Crustac Décapode.

Free fatty acids extracted from the abdominal muscle of Palaemon serratus (Crustacea, Decapoda) maintained on a L-D: 19-5 photoperiod show important circadian variations, characterised by two diurnal maximums and one nocturnal by the end of dark period. Principal maximum is diurnal and occurs 7 hours after the beginning of the light phase.

[Characterization of various digestive enzyme activities of Palaemon serratus Pennant (Crustacea, Decapoda) after polyacrylamide gradient gel electrophoresis]. / Caractérisation de guelques activités enzymatiques digestives de Palaemon serratus Pennant (Crusta-é, Décapode), après électrophorèse sur gel en gradient de polyacrylamide

Soluble proteins of hepatopancreatic, extracts of Palaemon serratus (Crustacea, Deapoda) are separated by polyacrylamide gradient gel electoresis. The characterisation of the enzymatic activities is carried out directly on the polyacrylamide gel. The zymogram includes the following activities: acid and alcalin phosphatses, phosphamidase, alpha-glucosidase, beta-glucosaminidase, beta-glucuronidase and twenty bands with esterasic activities. The molecular weights are indicated.

[Accumulation of Fe, Cu, Zn, Mg, Mn and Co in the ovary of Carcinus maenas L. during ovogenesis]. / Accumulation de Fe, Cu, Zn, Mg, Mn et Co dans l'ovaire de Carcinus maenas L. au cours de l'ovogenèse

During ovogenesis the ovary of Carcinus maenas shows a continuous accumulation of Fe, Cu, Mg, Mn and Co. For Zn the accumulation seems to stop for gonad indexes near 6.5. The goal of this accumulation is not determined. Nevertheless we suppose that it is in relation with the role of organic reserves that possess the female sexual cells in decapods and with the synthesis of enzymes and hemocyanin.

[Metabolism of the Fe, Cu, Zn, Mg, MN and Co in the ovum of Cancer irroratus (decapod crustacean)]. / Métabolisme de Fe, Cu, Zn, Mg, Mn et Co dans les oeufs de Cancer irroratus (Crustacé Décapode)

The concentrations of Fe, Cu, Zn, Mn and Co in the eggs of Cancer irroratus show variations in relation with time running out after laying, that is to say with embryogenesis. The increase of the rates of Fe, Mn and Mg is independant of the variations of the water content. Inversely, the decrease of Cu and Zn concentrations is in close relation with the increase of water content during the same period. The increase of Fe, Mn and Mg concentrations seems to be essentially under the dependance of physico-chemical, rather than biochemical, process in connection with the chitinous nature of the membranes surrounding the egg.