Zeitschrift für Meeresbiologie und Ozeanographie

Searching for Radical Solutions against Fouling Communities Inhabiting the Arabian Gulf in Saudi Arabia

Saad GA, Hussein AB and Abu El-saad AM

Searching for Radical Solutions against Fouling Communities Inhabiting the Arabian Gulf in Saudi Arabia

Sea squirts produce pelagic larvae that spend few days in the plankton before settling and metamorphosing into their adult sessile forms. Attachment mechanism developed usually relies on highly viscous or solid adhesive secretions, which all contain specialized proteins and glycogen. Adult sea squirts of Ciona intestinalis, Molgula manhattensis, Ascidella aspersa and Phallusia nigra were sampled for 12 months from three estuarine localities of the Arabian Gulf (Ad-Dammam; Northern Khobar and Southern Khobar). Seasonal variation of some analyzed abiotic factors revealed that the population densities of ascidians and the feasibility of larval dispersal were variable not only according to seasons but also according to the study locality where ascidians predominate Southern Khobar˃Northern Khobar ≈ Ad-Dammam and during spring and summer populations are ˃˃ those of autumn < those of winter. Procurement of gametes has been carried out by potassium chloride injection or/and artificial heterologous fertilization. Larvae were cultured and three larval stages were identified. Immunocytochemical approach has been applied to investigate larval metamorphosis under the influence of applied bioactive inducers which had been claimed to induce metamorphosis or involved in signaling systems or serve as neurotransmitters or control morphogenetic and behavioral reactions or interact with members of several signal transduction proteins pathways. The transformation of the larval stage with long tail to the next larval stage with remarkable tail resorption activity is accelerated by NH4Cl 2.5 mM, C8 1 μM, Acetyl choline 1 mM, NOS 1 mM and cGMP 1 μM. To investigate whether NO and HSP 90 play a role in larval metamorphosis, larvae with long tail, partially metamorphosed larvae with short tail and metamorphosing youngs were treated for whole-mount immunohistochemistry towards the green fluorescent protein (GFP). High-pressure chromatographic separation has been carried out to identify amino acids in the adhesive secretions of the larval stage. Western blotting routine technique (Immune blotting) using Bradford assay has been applied to identify proteins of adhesives. SDS-PAGE revealed that the adhesives contained about 11 different proteins. Their apparent molecular masses were approximately 300, 280, 250, 150, 100, 75, 50, 35, 25, 20, and 10 kDa. Total lipids were extracted using capillary gas chromatography and total carbohydrates of adhesives were analyzed by the Phenolsulphuric acid method. This study concluded that lipids of adhesives is secreted first and represented by C14:0; C18:2 V-32; C20:1 V-9; C18:1 V-7; C16:1 V-6 and C18:1 V-5. A post-translational modification of amino acids mainly Phenylalanine, Methionine Threonine, Valine and Serine with glycogen for adhesive and cohesive function occurs. The carbohydrate moiety of adhesives is a polymerization of monosaccharides. All data obtained were subjected to analysis of variance (ANOVA) means significant difference P>0.05 or P<0.05, column comparison test P<0.0001; Df 51-207 and Tukey post hoc test. Bartlett’s test for equal variances P value 0, 4095 has been applied. This study suggested that a fine powdery copper catalyst or boric acid esters and Didecyl polyoxyethyl ammonium borate (DPAB) have to be added as antifouling agents to the paint materials of ships, boats and steels objects in the Arabian Gulf to minimize or prevent fouling stress.