The ontogeny of greater amberjack digestive and antioxidant defence systems under different rearing conditions: A histological and enzymatic approach

An overall synchronization of morphological and physiological ontogenetic events of the digestive and antioxidant defence systems occurred in greater amberjack (Seriola dumerili) larvae reared under intensive (INT) or semi‐intensive (MES) conditions for 30 days. The first differentiations of the digestive channel took place at 3–4 days post‐hatch (dph) (3.6–3.7 mm). Differentiation of the endocrine and exocrine pancreas begun at 4–5 dph (4.0–4.1 mm), coinciding with a decrease in carbohydrase activity from egg to the onset of exogenous feeding and the maintenance of bile salt‐activated lipase and total alkaline proteases. The first gastric glands and pepsin activity were evident at 17–20 dph (5.5–6.2 mm) in both fish groups. The appearance of pyloric caeca had a 5‐day delay in the INT compared to the MES larvae (28 versus 23 dph). Antioxidant enzyme activities decreased progressively from 7 to 30 dph in both rearing conditions. However, GPx, SOD at 7 and 18 dph, and GST activities were higher in the INT larvae. Although both larval groups did not globally differ in somatic growth and maturation of digestive function, it seems that the antioxidant defence system of MES larvae had to face less oxidative assaults, which may be attributed to lower stressful and more stable culture conditions.info:eu-repo/semantics/acceptedVersio

Surfactant-based oil dispersant toxicity to developing nauplii of Artemia: Effects on ATPase enzymatic system

The paper deals with the toxicity of a surfactant-based oil dispersant to the ATPase activities of two naupliar stages of Artemia (instar I & II). Both instars were exposed to sub-lethal and lethal concentrations derived from acute toxicity data. The chosen concentrations were near to LOECs and NOECs. An eightfold difference indicated between the instars was instar-exposure time dependent. The most prominent effects were the inhibition and the stimulation of Na+/K+-ATPase and Mg2+-ATPase activities, respectively. The cause of these effects was related to the dispersant components, the surfactants. The pattern stimulation/inhibition of Mg2+-ATPase and Na+/K+-ATPase activities could be used to indicate toxic stress by surfactant-based oil dispersants since previous studies with other contaminants have shown different ATPase activity patterns. © 2001 Elsevier Science Ltd

Genome-wide identification of serine acetyltransferase (SAT) gene family in rice (Oryza sativa) and their expressions under salt stress

Background Assimilation of sulfur to cysteine (Cys) occurs in presence of serine acetyltransferase (SAT). Drought and salt stresses are known to be regulated by abscisic acid, whose biosynthesis is limited by Cys. Cys is formed by cysteine synthase complex depending on SAT and OASTL enzymes. Functions of some SAT genes were identified in Arabidopsis; however, it is not known how SAT genes are regulated in rice (Oryza sativa) under salt stress. Methods and results Sequence, protein domain, gene structure, nucleotide, phylogenetic, selection, gene duplication, motif, synteny, digital expression and co-expression, secondary and tertiary protein structures, and binding site analyses were conducted. The wet-lab expressions of OsSAT genes were also tested under salt stress. OsSATs have underwent purifying selection. Segmental and tandem duplications may be driving force of structural and functional divergences of OsSATs. The digital expression analyses of OsSATs showed that jasmonic acid (JA) was the only hormone inducing the expressions of OsSAT1;1, OsSAT2;1, and OsSAT2;2 whereas auxin and ABA only triggered OsSAT1;1 expression. Leaf blade is the only plant organ where all OsSATs but OsSAT1;1 were expressed. Wet-lab expressions of OsSATs indicated that OsSAT1;1, OsSAT1;2 and OsSAT1;3 genes were upregulated at different exposure times of salt stress. Conclusions OsSAT1;1, expressed highly in rice roots, may be a hub gene regulated by cross-talk of JA, ABA and auxin hormones. The cross-talk of the mentioned hormones and the structural variations of OsSAT proteins may also explain the different responses of OsSATs to salt stress.WOS:0006847827000012-s2.0-85112445896PubMed: 3438992

Aquaculture Multi Trophique Intégrée : le projet IMTA Effect

National audienc