Motility of sea urchin Paracentrotus lividus spermatozoa in the post‐activation phase

The characterization of sperm motility patterns, particularly post-activation changes, is the first step in setting up species-specific protocols involving gamete management and embryo production, for both aquaculture and laboratory research purposes. This study is aimed at the characterization of the sperm motility pattern of the purple sea urchin Paracentrotus lividus. Semen samples were individually diluted in artificial sea water for sperm motility activation. They were then incubated at 18°C for up to 24 hr. Motility was evaluated on dilution, and 1 hr, 3 hr and 24 hr after activation, by computerized analyser. The semen fertilization capacity was also evaluated. Under our experimental conditions (dilution 1:1,000 in artificial sea water plus 0.05% BSA, 18°C, in the dark), P. lividus semen remained viable for up to 24 hr, as the total motile sperm and the fertilization percentages did not change significantly during the incubation time. In contrast, the mean curvilinear velocity and the subpopulation of rapid sperm (those having a curvilinear velocity > 100 µm/s) slightly but significantly decreased after 3 hr, thereafter remaining unchanged for up to 24 hr after activation. In conclusion, our results show that diluted P. lividus semen can be used for a longer period than that of most fish species, with no need for motility inhibition procedures, supporting its wider use in laboratory research. In addition, the development of artificial fertilization protocols for aquaculture production is simplified by long-lasting sperm motility

Increasing the stocking density in Paracentrotus lividus larviculture: Effects on survival and metamorphosis rates

The development of sustainable methods for sea urchin juvenile production is currently constrained by high mortality rates during larval growth and the high costs of larval rearing systems management. With the aim of developing a method for the production of juveniles of the purple sea urchin Paracentrotus lividus in a medium-scale recirculating system, the present study focused on the effects of high stocking densities on larval growth. Plutei larvae were reared at three different densities (up to 7 ind/ml) in a semi-static culture system. Larval survival and metamorphosis success were evaluated in order to identify the most effective density range. The highest metamorphosis rates (80%-95%) were obtained at 4 and 7 larvae/ml. These results are comparable with (and in some cases higher than) those reported for the same species at much lower larval densities. In conclusion, the rearing conditions tested here show for the first time that a significantly higher (4 ind/ml) stocking density than those of traditional P. lividus rearing methods (based on large volumes and low densities) can be adopted, thus supporting the feasibility of an increase in the final output of competent larvae with no increase in rearing volumes

Paracentrotus lividus roe enhancement by a short-time rearing in offshore cages using two agar-based experimental feed

In this study, we tested the effect of two agar-based biocomposites (differing for the fish meal source), on the Paracentrotus lividus gonad cycle progression and biochemical composition, in an offshore pilot scale trial. The purpose of this study was to identify a feeding regime for P. lividus that would allow adequate gonadal growth without accelerating the gamete maturation, in order to extend the market period. The purpose was pursued through the use of agar as a binding agent in the manufacturing of biocomposites to be used as feed for P. lividus and the realization of special offshore cages. The gonad index, histology, biochemical composition of fatty acids (FA) and free amino acids (FAA) and volatile molecule fingerprint were evaluated. Both the gonad index and the histological analysis showed a slower gametogenesis progression in the gonads of caged sea urchins with respect to the field collected ones, consistent with our previous results obtained testing a similar feed composition in a recirculating system. The amount and the relative proportions of FA and FAA in the gonads of wild and cultured gonads were similar, while the analysis of the volatile substances of the gonads of the sea urchin conducted using the electronic nose, shows that they vary as a result of the different feeding treatments. These results show that P. lividus sea urchins can be housed, under this feeding regime during the recovery phase of the gonads, without acceleration of the maturation of the gametes and thus in conditions to allow the extension of the market period. Moreover, the here tested agar-based biocomposites make it possible to reduce the management costs of the rearing system as they need to be replaced only once a week, and its environmental impact as they guarantee a limited nutrient dispersion in the water

Deletion of the mental retardation gene Gdi1 impairs associative memory and alters social behavior in mice

Non-specific mental retardation (NSMR) is a common human disorder characterized by mental handicap as the only clinical symptom. Among the recently identified MR genes is GDI1, which encodes αGdi, one of the proteins controlling the activity of the small GTPases of the Rab family in vesicle fusion and intracellular trafficking. We report the cognitive and behavioral characterization of mice carrying a deletion of Gdi1. The Gdi1-deficient mice are fertile and anatomically normal. They appear normal also in many tasks to assess spatial and episodic memory and emotional behavior. Gdi1-deficient mice are impaired in tasks requiring formation of short-term temporal associations, suggesting a defect in short-term memory. In addition, they show lowered aggression and altered social behavior. In mice, as in humans, lack of Gdi1 spares most central nervous system functions and preferentially impairs only a few forebrain functions required to form temporal associations. The general similarity to human mental retardation is striking, and suggests that the Gdi1 mutants may provide insights into the human defect and into the molecular mechanisms important for development of cognitive function

L'Italia come modello per l'Europa e per il mondo nelle politiche sanitarie per il trattamento dell'epatite cronica da HCV

The World Health Organization foresees the elimination of HCV infection by 2030. In light of this and the curre nt, nearly worldwide, restriction in direct-acting agents (DAA) accessibility due to their high price, we aimed to evaluate the cost-effectiveness of two alternative DAA treatment policies: Policy 1 (universal): treat all patients, regardless of the fibrosis stage; Policy 2 (prioritized): treat only priori tized patients and delay treatment of the remaining patients until reaching stage F3. T he model was based on patient’s data from the PITER cohort. We demonstrated that extending HC V treatment of patients in any fibrosis stage improves health outcomes and is cost-effective

Agar-based Biocomposites slow down Progression in the Reproductive Cycle Facilitating Synchronization of the Gonads of Reared Specimens of Paracentrotus lividus

Background: Biopolymers have many fields of application. In Echiniculture they are usually employed to bind trial diets, although a systematic study on the performances of biopolymers as feed binders is lacking.&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Methods: Several biopolymers (sodium alginate, agar, gellan, apple pectin and citrus pectin with different esterification degree) were employed as binders in the manufacture of biocomposites to be used as Paracentrotus lividus feed. Biocomposites were first produced with varying percentages of feed ingredients (5-25%) and polymers (2-3%), either alone or in blends of two types. Biocomposites were tested for stability, swelling and nutrient release in water. In order to evaluate their palatability, biocomposites were administered to sea urchins and eating activity checked up to 48 h. GI and gonad composition were evaluated in a 14-week rearing trial.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Result:Agar and apple pectin gave the best results in terms of stability, swelling and nutrient release in water and were well accepted by sea urchins. When tested in the rearing trial both biocomposites produced a slow progression in the reproductive cycle, more marked in the agar-based ones.Conclusion: This study demonstrates that agar has promising features as a binder in the formulation of diets for Paracentrotus lividus. Agar biocomposites were readily accepted by urchins, absorbed a minimal amount of water, and produced negligible waste and nutrient dispersal in the rearing system. Moreover, slower progression in the reproductive cycle facilitates synchronization of the gonads of reared specimens to the desired reproductive state. Finally, being their nutrient composition easily adjustable according to specific rearing needs, agar biocomposites are an interesting starting-point for the formulation of highly versatile prepared feed.</p

Misure di temperature in ambiente marino

Comprendere il comportamento, l'evoluzione e le caratteristiche del mare è una questione essenziale per affrontare alcune grandi sfide attuali in materia di ambiente: il cambiamento climatico, il ciclo del carbonio, l'acidificazione degli oceani, le variazioni della circolazione marina e i loro effetti, ecc. Per questo, il numero di studi sul mare è in aumento da alcuni anni a questa parte. La temperatura del sistema-mare è esplicitamente menzionata nell'allegato III della Marine Strategy Framework Directive (2008) come uno dei parametri che richiedono maggiore attenzione. Le misurazioni significative e coerenti della temperatura dell'acqua di mare sono essenziali per comprendere la sua influenza in quasi tutti i processi marini, nonché per comprendere i meccanismi di scambio di calore tra il mare e l'atmosfera

Agar-based pellets for sea urchins

AbstractThealgalpolysaccharideagarhaslongbeenusedasa food binderdue toits structure, rheological beha-viour, stability and interactions ^ properties thathelp to generate ¢rm, round, disk-shaped pelletsthat may be used in recirculating sea urchin-rear-ing systems. Three algae-based diets (Ulva lactuca,Gracilaria gracilis, Cystoseira sp.) containing 3%and 6% agar weretestedonthe seaurchin Paracen-trotuslividusin order to examine the eiect of vary-ing percentages of agar on pellet stability in waterand seaurchingonadgrowth.Thekinetics of waterabsorptionand soluteleachingof pellets were mea-sured by immersing quadruplicate samples of thepelletsinwaterfor1,2,3,4,5and6days.Ourresultsshow that the pellets had good water stability, werereadily consumed by sea urchins and the presenceof agar did not hamper sea urchin gonad growth.Animals fed Ulva-containing pellets reached amore advanced gametogenic stage with respect toanimals fed Cystoseira- and Gracilaria-containingpellets. Moreover, the presence of agarase activityin the digestive system indicated that agar may bean energysource. Pellets are relativelylowcostandeasy to prepare and store. They may represent ausefulresourceforrearingseaurchinsunderinten-sive conditions.Keywords: sea urchin, agar pellets, rheologicalbehaviour,growth, digestiveenzymesIntroductionThe last few years have seen growing interest in thedevelopment of sea urchin culture methods as theworld's wild stocks of many sea urchin species havesuieredfromunregulatedexploitationandotherhu-man activities (Guidetti, Fraschetti,Terlizzi & Boero2003).This is particularly true for Paracentrotus livi-dus (Lamarck, 1816), a macro-algivore sea urchincommonly found along North Atlantic coasts fromIreland to Southern Morocco and throughout theMediterranean sea (Bayed, Quiniou, Benrha & Guil-lou 2005). It is highly valued for its edible gonads(called roe); inaddition,it hasbeenusedsuccessfullyasananimal model in manyscienti¢c ¢elds, rangingfrom basic biology including developmental biologyand cell diierentiation (Kominami & Takata 2004)toapplied biology includingecotoxicology (Fabbroci-ni,Guarino,Scirocco, Franchi& D'Adamo2005).Either raised for use as laboratory animal modelsor farmed on a large scale for human consumption,successful production relies on correct feeding andthis is not always easy. There is a considerableamount of literature dealing with feeding strategiesto optimize seaurchingrowthand produce ¢rmandcompactgonads(Pearce,DaggettRShpigel, McBride, Marciano, Ron & Ben-Amotz 2005;Cook & Kelly 2007a; Siikavuopio, Dale & Mortensen2007; Siikavuopio, Mortensen & Christiansen 2008;Gibbs,Watts, Lawrence & Lawrence 2009). Innumer-able diets to accelerate growth and improve £avou