The influence of season on the gonad index and biochemical composition of the sea urchin Paracentrotus lividus from the Golf of Tunis

Edible Sea urchins Echinus esculentus from Norwegian waters- Effect of season on nutritional quality and chemical contaminants

This study aimed to characterize Echinus esculentus gonads in terms of biometric parameters and nutritional quality at two sites in Mid-Norway at four different seasons. The chemical contamination of the gonads was also investigated for the first time through the evaluation of 28 macro- and trace elements and 32 components from the emerging and persistent group per- and polyfluoroalkyl substances (PFAS). The spawning period was determined in summer, given that the gonad index was the lowest in this season for both sites. Protein concentrations were constant (8%-10%). However, lipid contents (1%-3%) were noticed to be higher in gonads during autumn and winter. The gonads had high contents of PUFA mainly EPA and DHA, followed by SFA, and MUFA year around for both locations. E. esculentus gonads constitute a good source of fatty acids, macro, and trace elements. This species could also be a bioindicator for the monitoring of marine environments.

Metallic trace element dynamics in Paracentrotus lividus from Algeria: Environmental large-scale survey and human health risk assessment

This paper evaluates the dynamics of Metallic Trace Elements (MTEs; Cd, Pb, Fe, Cu, Zn, Ni and Co) in the gonads of the sea urchin Paracentrotus lividus collected in five sites: four contaminated and one reference, along the Western coast of Algeria, recontextualizes this contamination within a wider geographical distribution area throughout 83 sites among the Mediterranean Sea and Atlantic and focuses on the potential risk of their consumption on human health for the first time in Algeria. The trace element pollution index places Algeria, and generally the North African coasts, as the region most contaminated by MTEs. The geographical variability in metal contamination levels is greater in the Mediterranean Sea than in the Atlantic. The health risk assessment indicates that Pb exceeds the maximum limit set by the Commission Regulation (EC) No 1881/2006 at two of the four Algerian contaminated sites.

Dual oxidative stress and fatty acid profile impacts in Paracentrotus lividus exposed to lambda-cyhalothrin: biochemical and histopathological responses

Lambda-cyhalothrin (λ-cyh) is a potential pyrethroid insecticide widely used in pest control. The presence of pyrethroids in the aquatic ecosystem may induce adverse effects on non-target organisms such as the sea urchin. This study was conducted to assess the toxic effects of λ-cyh on the fatty acid profiles, redox status, and histopathological aspects of Paracentrotus lividus gonads following exposure to three concentrations of λ-cyh (100, 250 and 500 µg/L) for 72 h. The results showed a significant decrease in saturated fatty acid (SFAs) with an increase in monounsaturated fatty acid (MUFAs) and polyunsaturated fatty acid (PUFAs) levels in λ-cyh treated sea urchins. The highest levels in PUFAs were recorded in the eicosapentaenoic acids (C20:5n-3), docosahexaenoic acids (C22:6n-3) and arachidonic acids (C20:4n-6) levels. The λ-cyh intoxication promoted oxidative stress with an increase in hydrogen peroxide (H2O2), malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels. Furthermore, the enzymatic activities and non-enzymatic antioxidants levels were enhanced in all exposed sea urchins, while the vitamin C levels were decreased in 100 and 500 µg/L treated groups. Our biochemical results have been confirmed by the histopathological observations. Collectively, our findings offered valuable insights into the importance of assessing fatty acids' profiles as a relevant tool in aquatic ecotoxicological studies.

Sex-specific seasonal variations in the fatty acid and carotenoid composition of sea cucumber gonads and implications for aquaculture

Fatty acids and carotenoids are known to have roles in embryonic and larval development of sea cucumbers, but their changes in gonads during gametogenesis have not yet been studied. To improve our knowledge of the reproductive cycle of sea cucumbers in an aquaculture perspective, we collected 6-11 individuals of the species Holothuria (Panningothuria) forskali Delle Chiaje, 1823 approximately every 2 months from December 2019 to July 2021 east of the Glenan Islands (Brittany - France; 47.710°N, 3.948°W) at a depth of 8-12 m. Our results show that soon after spawning, sea cucumbers take advantage of an increased food availability in spring to rapidly and opportunistically accumulate nutrients in the form of lipids in their gonads (from May to July) and then slowly elongate, desaturate and probably rearrange fatty acids within lipid classes for the next reproductive season according to the specific requirements of both sexes. In contrast, acquisition of carotenoids occurs synchronously with gonads filling and/or through the reabsorption of spent tubules (T5), thus revealing little seasonal variations at the scale of the entire gonad in terms of relative abundance in both sexes. All results suggest that gonads are fully replenished with nutrients by October and that broodstock for induced reproduction could be captured at this moment and kept until the production of larvae is required. Maintaining broodstock for consecutive years would probably be a higher level challenge as the dynamics of tubule recruitment are not fully understood and seem to last for several years.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00227-023-04198-0.

Metallic trace element dynamics in Paracentrotus lividus from Algeria: Environmental and human health risk assessment

This paper evaluates the dynamic of Metallic Trace Elements (MTEs; Cd, Pb, Fe, Cu, Zn, Ni and Co) in the sea urchin Paracentrotus lividus collected in five sites: four contaminated and one reference, along the western coast of Algeria, recontextualizes this contamination within a wider geographical distribution area throughout 84 sites among the Mediterranean Sea and Atlantic and focuses on the potential risk on human health for the first time in Algeria. The Trace Element Pollution Index places Algeria, and generally the North African coasts, as the region most contaminated by MTEs. The Trace Element Spatial Variation Index ranks Pb as a MTE of key environmental concern according to global spatial variability. The health risk assessment indicates that Cd and Pb exceed the maximum limits set by the Commission Regulation (EC) No 1881/2006 on three of the four contaminated sites.

Fatty Acids of Echinoderms: Diversity, Current Applications and Future Opportunities

The phylum Echinodermata comprising the classes Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea, and Crinodeia, is one of the important invertebrate groups. Members of this phylum live exclusively in marine habitats and are distributed in almost all depths and latitudes. Some of them, such as sea urchins and sea cucumbers, are commercially valuable and constitute a major fishery resource. Echinoderms are increasingly recognized as a unique source of various metabolites with a wide range of biological activities. The importance of dietary polyunsaturated fatty acids, such as eicosapentaenoic acid, in human health has drawn attention to echinoderms as a promising source of essential fatty acids (FAs). Extensive information on the FAs of the phylum has been accumulated to date. The biosynthetic capabilities and feeding habits of echinoderms explain the findings of the unusual FAs in them. Certain common and unusual FAs may serve as chemotaxonomic markers of the classes. The main goal of the review was to gather the relevant information on the distribution of FAs among the echinoderm classes, describe the structures, distribution, biosynthetic pathways, and bioactivity, with an emphasis on the FAs specific for echinoderms. A large part of the review is devoted to the FAs derived from echinoderms that exhibit various biological activities promising for potential therapeutic applications.

Metabolomics Unravels Grazing Interactions under Nutrient Enrichment from Aquaculture

Our goal was to understand the mechanisms behind the impact of nutrient enrichment at intermediate distances from aquaculture on the interactions of a subtidal macroalgae community with its main grazer, the sea urchin Paracentrotus lividus. We assessed the diversity and cover of the macroalgal community, the abundance and biometrics of the sea urchins, the carbon and nitrogen elemental and isotopic compositions, and their metabolome in two stations, at an intermediate distance (station A) and away (station B) from a fish cage facility in the Aegean Sea (Greece), during the warm and cold seasons. The nutrient input at station A favored a shift to a macroalgal assemblage dominated by turf-forming species, depleted of native-erected species and with a higher abundance of invasive algae. A stable isotope analysis showed fish-farm-associated nitrogen enrichment of the macroalgae and trophic transfer to P. lividus. A decrease in metabolites related to grazing, reproduction, and energy reserves was found in P. lividus at station A. Furthermore, the metabolomic analysis was able to pinpoint stress in P. lividus at an intermediate distance from aquaculture. The chosen combination of traditional ecology with omics technology could be used to uncover not only the sublethal effects of nutrient loading but also the pathways for species interactions.

Lipid metabolism of sea urchin Paracentrotus lividus in two contrasting natural habitats

Sea urchins Paracentrotus lividus were harvested monthly from April 2015 to March 2016 from two sites in Sardinia (Italy). The two sites, a Posidonia oceanica meadow and a rocky bottom habitat, were naturally characterized by different food sources and availability, being mainly populated by the sea grass Posidonia oceanica and the brown algae Halopteris scoparia, respectively. Total lipids showed a minimum during winter in mature gonads, and a maximum in the summer (recovery stage). Fatty acid (FA) profiles of gut contents and gonads differed from those of the most available food sources. Levels of C18:3 (n-3) (ALA) discriminated samples from the two sites. Despite the very low amounts of C20:5 (n-3) (EPA) and C20:4 (n-6) (ARA) in P. oceanica, the main FA in gonads and gut contents were EPA and ARA in both sites. Increase in green algae intake prior to gametogenesis, especially C. cylindracea, likely affected EPA and ARA levels in gonads. The results show that P. lividus is able to concentrate lipids in gut contents and also to selectively store EPA, ARA and their precursors ALA and 18:2 (n-6) (LA). Moreover, bioconversion of ALA to EPA and of LA to ARA in P. lividus is suggested.

The Echinodermata PPAR: Functional characterization and exploitation by the model lipid homeostasis regulator tributyltin

The wide ecological relevance of lipid homeostasis modulators in the environment has been increasingly acknowledged. Tributyltin (TBT), for instance, was shown to cause lipid modulation, not only in mammals, but also in fish, molluscs, arthropods and rotifers. In vertebrates, TBT is known to interact with a nuclear receptor heterodimer module, formed by the retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor (PPAR). These modulate the expression of genes involved in lipid homeostasis. In the present work, we isolated for the first time the complete coding region of the Echinodermata (Paracentrotus lividus) gene orthologues of PPAR and RXR and evaluated the ability of a model lipid homeostasis modulator, TBT, to interfere with the lipid metabolism in this species. Our results demonstrate that TBT alters the gonadal fatty acid composition and gene expression patterns: yielding sex-specific responses in fatty acid levels, including the decrease of eicosapentaenoic acid (C20:5 n-3, EPA) in males, and increase of arachidonic acid (20:4n-6, ARA) in females, and upregulation of long-chain acyl-CoA synthetase (acsl), ppar and rxr. Furthermore, an in vitro test using COS-1 cells as host and chimeric receptors with the ligand binding domain (LBD) of P. lividus PPAR and RXR shows that organotins (TBT and TPT (Triphenyltin)) suppressed activity of the heterodimer PPAR/RXR in a concentration-dependent manner. Together, these results suggest that TBT acts as a lipid homeostasis modulator at environmentally relevant concentrations in Echinodermata and highlight a possible conserved mode of action via the PPAR/RXR heterodimer.

Quantitative Proteome Reveals Variation in the Condition Factor of Sea Urchin Strongylocentrotus nudus during the Fishing Season Using an iTRAQ-based Approach

To investigate the variation in the condition factor of the sea urchin Strongylocentrotus nudus (S. nudus), gonads were collected in May (MAY), June (JUN), and July (JUL), at the beginning (AUG-b) and end of August (AUG-e). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) detection of the gonads revealed an obvious enhancement of the band at about 37 kDa from July, which was identified as transforming growth factor-beta-induced protein ig-h3 (TGFBI) by nanoLC-ESI-MS/MS. Gonadal proteins were identified by isobaric tagging for relative and absolute quantitation (iTRAQ), and regulation of the identified proteins in pairs of the collected groups was observed. A total of 174 differentially expressed proteins (DEPs) were identified. Seven of the DEPs showed significant correlations with both the gonad index (GI) and protein content. These correlations included 6-phosphogluconate dehydrogenase, decarboxylating isoform X2 (6PGD), CAD protein, myoferlin isoform X8, ribosomal protein L36 (RL36), isocitrate dehydrogenase [NADP], mitochondrial isoform X2 (IDH), multifunctional protein ADE2 isoform X3, sperm-activating peptides (SAPs) and aldehyde dehydrogenase, and mitochondrial (ALDH). However, TGFBI had no correlation with gonad index (GI) or protein content. 6PGD, IDH, multifunctional protein ADE2 isoform X3, and ALDH were shown to interact with each other and might play key roles in changing the condition factor of S. nudus gonads.

The effect of sex, season and gametogenic cycle on gonad yield, biochemical composition and quality traits of Paracentrotus lividus along the North Atlantic coast of Portugal

Sea urchin population harvest in the North Atlantic coast of Portugal was characterized in terms of gonad yield, nutritional composition and important market-related traits, over one reproductive cycle (March 2016 to March 2017). Most of the quality attributes showed a seasonal variation strongly dependent on sea urchin sex. Maximum gonad yield (18%) was observed in March 2017. A single spawning event occurred between May and July. Gonads are rich sources of protein (12–18% WW) with low fat content (≤6% WW), that increase during the gametogenic stages of recovery and growing (November-December). Polyunsaturated fatty acids were the dominant class in both sexes (4.2–14.7 mg.g⁻¹ WW), being preferentially accumulated in females. Total gonads carotenoid varied seasonally, with the highest level being observed in males during spawning season. Echinenone was the main pigment present in gonads, showing highest concentrations in males during spawning and gonad recovering. During the growing and early maturation period gonads were more reddish, yellowish and brighter, as well as more firm, irrespectively of the sex. Based on all seasonal changes affecting gonad yield and quality, the period between November and February seems the most suitable to harvest high quality gonads in the Atlantic coast of Portugal.

7β-hydroxycholesterol-induced cell death, oxidative stress, and fatty acid metabolism dysfunctions attenuated with sea urchin egg oil

Some oxysterols resulting either from enzymatic oxidation or autoxidation of cholesterol are associated with age-related diseases including neurodegenerative diseases. Among these oxysterols, 7β-hydroxycholesterol (7β-OHC) is often found at increased levels in patients. It is therefore important to identify molecules or mixtures of molecules to prevent 7β-OHC-induced side effects. Consequently, murine oligodendrocytes (158N) were cultured in the absence or presence of 7β-OHC (20 μg/mL, 24 h) with or without a natural oil extracted from sea urchin (Paracentrotus lividus) eggs known for its biological activity. Firstly, the chemical composition of this oil was determined using ³¹P NMR and GC-MS. Secondly, this oil was used to reduce 7β-OHC-induced side effects. To this end, the oil (160 μg/mL) was added to the culture medium of 158N cells 2 h before 7β-OHC. The effects of 7β-OHC with or without the oil on cell viability were studied with the MTT test. Photometric methods were used to analyze antioxidant enzyme activities, superoxide dismutase (SOD) and glutathione peroxidase (GPx), as well as the generation of lipid peroxidation products (malondialdehyde (MDA), conjugated dienes (CDs)) and protein oxidation product (carbonylated proteins (CPs)). Gas chromatography was used to determine the fatty acid profile. With 7β-OHC, an induction of cell death associated with oxidative stress (alteration of GPx and SOD activities) was observed; an overproduction of lipid peroxidation products (MDA and CDs) and CPs was also revealed. Sea urchin egg oil attenuated 7β-OHC-induced cytotoxicity: 7β-OHC-induced cell death was reduced, GPx and SOD activities were normalized, and lower levels of MDA, CDs and CPs were produced. In addition, whereas a disturbed fatty acid profile was observed with 7β-OHC, similar fatty acid profiles were found in control cells and in cells cultured with 7β-OHC associated with sea urchin egg oil. These data demonstrate the protective activities of sea urchin egg oil against 7β-OHC-induced side effects on 158N cells, supporting the concept that this oil may have benefits in the prevention of neurodegenerative diseases.

Quality of a fished resource: Assessing spatial and temporal dynamics

Understanding spatio-temporal variability in the demography of harvested species is essential to improve sustainability, especially if there is large geographic variation in demography. Reproductive patterns commonly vary spatially, which is particularly important for management of “roe”-based fisheries, since profits depend on both the number and reproductive condition of individuals. The red sea urchin, Mesocentrotus franciscanus, is harvested in California for its roe (gonad), which is sold to domestic and international sushi markets. The primary driver of price within this multi-million-dollar industry is gonad quality. A relatively simple measure of the fraction of the body mass that is gonad, the gonadosomatic index (GSI), provides important insight into the ecological and environmental factors associated with variability in reproductive quality, and hence value within the industry. We identified the seasonality of the reproductive cycle and determined whether it varied within a heavily fished region. We found that fishermen were predictable both temporally and spatially in collecting urchins according to the reproductive dynamics of urchins. We demonstrated the use of red sea urchin GSI as a simple, quantitative tool to predict quality, effort, landings, price, and value of the fishery. We found that current management is not effectively realizing some objectives for the southern California fishery, since the reproductive cycle does not match the cycle in northern California, where these management guidelines were originally shaped. Although regulations may not be meeting initial management goals, the scheme may in fact provide conservation benefits by curtailing effort during part of the high-quality fishing season right before spawning.

Seasonal assessment of biological indices, bioaccumulation, and bioavailability of heavy metals in sea urchins Paracentrotus lividus from Algerian west coast, applied to environmental monitoring

The aim of the present work was to extend our knowledge on the variability of trace metals in sea urchin tissues, focusing on seasonal fluctuations (2010 February for "winter," May for "spring," August for "summer," November for "autumn") in the three different sampling sites of Algerian west coast (Oran Harbor (S1), Ain Defla (S2), and Hadjaj (belonging to Mostaganem City S3)). For this purpose, the bioavailability (metal indices) and bioaccumulation (metal concentrations in soft tissues) of heavy metals (Zn, Cu, Pb, and Cd), the physiological characteristics (e.g., biological indices such as condition index (CI), repletion index (RI), gonad index (GI)), and the biometric parameters (diameter (D) and the height (H)) of sea urchins Paracentrotus lividus were assessed and related to seasons and sites. To investigate the metal bioavailability to sea urchins more precisely, the metal indices were used as a reliable tool in the present work, instead of the metal concentrations only. The interest to standardize metal concentrations with the weight of the urchin test is to overcome the metal burden variations in the soft tissues of urchin related to the seasonal weight changes of the soft body of animal. We evidence that the most contaminated sites were S1 and S2. Furthermore, it should be noted that the bioavailability of metals, corresponding to the values of metal indices, is also more pronounced in S1 and S2 compared to that measured in S3. Thus, a correlation is observed between seasonal metal content in urchin tissues from the three sites and the corresponding metal indices. The high metal concentrations were obtained during the period when RI and CI were highest. So, it appears that the bioaccumulation of metals in sea urchins of the three sites studied is significantly influenced by the reproductive cycle and diet, feeding activity, and physiological state of these organisms. We noticed that the sea urchins from the sites S1 and S2 were small in size. It is probable that these animals, whose internal tissues contained high concentrations of metals, have been exposed to metal pollution, which might have affected both their growth and altered their physiological capacity. This approach is very original and might be used in the monitoring of the quality of coastal waters, and the present work provided a useful data set for Mediterranean monitoring network.

The evolution of gonad expenditure and gonadosomatic index (GSI) in male and female broadcast-spawning invertebrates

Sedentary broadcast-spawning marine invertebrates, which release both eggs and sperm into the water for fertilization, are of special interest for sexual selection studies. They provide unique insight into the early stages of the evolutionary succession leading to the often-intense operation of both pre- and post-mating sexual selection in mobile gonochorists. Since they are sessile or only weakly mobile, adults can interact only to a limited extent with other adults and with their own fertilized offspring. They are consequently subject mainly to selection on gamete production and gamete success, and so high gonad expenditure is expected in both sexes. We review literature on gonadosomatic index (GSI; the proportion of body tissue devoted to gamete production) of gonochoristic broadcast spawners, which we use as a proxy for gonad expenditure. We show that such taxa most often have a high GSI that is approximately equal in both sexes. When GSI is asymmetric, female GSI usually exceeds male GSI, at least in echinoderms (the majority of species recorded). Intriguingly, though, higher male GSI also occurs in some species and appears more common than female-biased GSI in certain orders of gastropod molluscs. Our limited data also suggest that higher male GSI may be the prevalent pattern in sperm casters (where only males release gametes). We explore how selection might have shaped these patterns using game theoretic models for gonad expenditure that consider possible trade-offs with (i) somatic maintenance or (ii) growth, while also considering sperm competition, sperm limitation, and polyspermy. Our models of the trade-off between somatic tissue (which increases survival) and gonad (which increases reproductive success) predict that GSI should be equal for the two sexes when sperm competition is intense, as is probably common in broadcast spawners due to synchronous spawning in aggregations. Higher female GSI occurs under low sperm competition. Sperm limitation appears unlikely to alter these conclusions qualitatively, but can also act as a force to keep male GSI high, and close to that of females. Polyspermy can act to reduce male GSI. Higher male than female GSI is predicted to be less common (as observed in the data), but can occur when ova/ovaries are sufficiently more resource-intensive to produce than sperm/testes, for which some evidence exists. We also show that sex-specific trade-offs between gonads and growth can generate different life-history strategies for males and females, with males beginning reproduction earlier. This could lead to apparently higher male GSI in empirical studies if immature females are included in calculations of mean GSI. The existence of higher male GSI nonetheless remains somewhat problematic and requires further investigation. When sperm limitation is low, we suggest that the natural logarithm of the male/female GSI ratio may be a suitable index for sperm competition level in broadcast spawners, and that this may also be considered as an index for internally fertilizing taxa.

Identification, expression analysis, and the regulating function on C/EBPs of KLF10 in Dalian purple sea urchin, Strongylocentrotus nudus

Accumulating evidence indicates that Krüppel-like factors (KLFs) play important roles in fat biology via the regulation of CCAAT/enhancer binding proteins (C/EBPs). However, KLFs and C/EBPs have not been identified from Strongylocentrotus nudus, and their roles in this species are not clear. In this study, the full-length cDNA of S. nudus KLF10 (SnKLF10) and three cDNA fragments of S. nudus C/EBPs (SnC/EBPs) were obtained. Examination of tissue distribution and expression patterns during gonadal development implied that SnKLF10 and SnC/EBPs play important roles in gonadal lipogenesis. The presence of transcription factor-binding sites (TFBSs) for KLFs in SnC/EBPs, and the results of an over-expression assay, revealed that SnKLF10 negatively regulates the transcription of SnC/EBPs. In addition, the core promoter regions of SnC/EBPs were determined, and multiple TFBSs for transcription factor (TFs) were identified, which are potential regulators of SnC/EBP transcription. Taken together, these results suggest that SnC/EBP genes are potential targets of SnKLF10, and that SnKLF10 plays a role in lipogenesis by repressing the transcription of SnC/EBPs. These findings provide information for further studies of KLF10 in invertebrates and provide new insight into the regulatory mechanisms of C/EBP transcription.

The role of fatty acids and triglycerides in the gonads of Paracentrotus lividus from Sardinia: Growth, reproduction and cold acclimatization

A detailed characterization of lipid extracts from gonads of P. lividus over a year has been performed combining GC and NMR measurements. For this purpose, sea urchins from two different Sardinian coastal areas were collected monthly. The results underlined a correlation between gonad fatty acids profiles and both water temperature and reproduction process. In particular, EPA and ARA appear to be the most altered fatty acids following seasonal changes. It is suggested that EPA could represent a biomarker of reproduction, reaching a content around 14% during gametogenesis, mainly due to an increase of the sn-1,3 position in TAGs. On the contrary, ARA seems to play a more important role in response to cold acclimatization, which is reflected in a modulation of ARA content in the sn-1,3 position in TAGs.

The gut microbiome of the sea urchin, Lytechinus variegatus, from its natural habitat demonstrates selective attributes of microbial taxa and predictive metabolic profiles

In this paper, we describe the microbial composition and their predictive metabolic profile in the sea urchin Lytechinus variegatus gut ecosystem along with samples from its habitat by using NextGen amplicon sequencing and downstream bioinformatics analyses. The microbial communities of the gut tissue revealed a near-exclusive abundance of Campylobacteraceae, whereas the pharynx tissue consisted of Tenericutes, followed by Gamma-, Alpha- and Epsilonproteobacteria at approximately equal capacities. The gut digesta and egested fecal pellets exhibited a microbial profile comprised of Gammaproteobacteria, mainly Vibrio, and Bacteroidetes. Both the seagrass and surrounding sea water revealed Alpha- and Betaproteobacteria. Bray-Curtis distances of microbial communities indicated a clustering profile with low intrasample variation. Predictive metagenomics performed on the microbial communities revealed that the gut tissue had high relative abundances of metabolisms assigned to the KEGG-Level-2 designation of energy metabolisms compared to the gut digesta, which had higher carbohydrate, amino acid and lipid metabolisms. Overall, the results of this study elaborate the spatial distribution of microbial communities in the gut ecosystem of L. variegatus, and specifically a selective attribute for Campylobacteraceae in the gut tissue. Also, the predictive functional significance of bacterial communities in uniquely compartmentalized gut ecosystems of L. variegatus has been described.

Mechanisms of echinochrome potency in modulating diabetic complications in liver

BACKGROUND

Diabetes mellitus is one of the most public metabolic disorders. It is mainly classified into type 1 and type 2. Echinochrome is a pigment from sea urchins that has antioxidant, anti-microbial, anti-inflammatory and chelating abilities.

AIMS

The present study aimed to investigate the anti-diabetic mechanisms of echinochrome pigment in streptozotocin-induced diabetic rats.

MAIN METHODS

Thirty six male Wistar albino rats were divided into two main groups, type 1 diabetes and type 2 diabetes groups. Each group was divided into 3 subgroups (6 rats/subgroup); control, diabetic and echinochrome groups. Diabetic model was induced by a single dose of streptozotocin (60mg/kg, i.p) for type 1 diabetes and by a high fat diet for 4weeks before the injection with streptozotocin (30mg/kg, i.p) for type 2 diabetes. Diabetic groups were treated orally with echinochrome extract (1mg/kg body weight in 10% DMSO) daily for 4weeks.

KEY FINDINGS

Echinochrome groups showed a reduction in the concentrations of glucose, MDA and the activities of arginase, AST, ALT, ALP and GGT. While it caused general increase in the levels of insulin, TB, DB, IB, NO and the activities of G6PD, GST, GPx, SOD and GSH. The histopathological investigation showed partial restoration of pancreatic islet cells and clear improvement in the hepatic architecture.

SIGNIFICANCE

The suggested mechanism of Ech action in the reduction of diabetic complications in liver involved two pathways; through the hypoglycemic activity and the antioxidant role of Ech.

Influence of seasonal and environmental patterns on the lipid content and fatty acid profiles in gonads of the edible sea urchin Paracentrotus lividus from Sardinia

The influence of seasonal and environmental patterns on the lipid fraction of Paracentrotus lividus gonads was investigated. For this purpose, sea urchins were collected monthly over a year from two Sardinian coastal areas. Total lipids in gonads follow an annual cyclical trend, described by a sine wave curve, that it is more influenced by season than by growing area. The lowest lipid content in gonads corresponds to a high percentage of mature reproductive stages (i.e. winter season), independently of sampling area. A variation in total lipid content follows a change in photoperiod, while it is related to sea surface temperature. Multivariate analysis on fatty acid profiles of gonads, detected by gas chromatography, clusters the collected specimens mainly according to the sampling area, secondly according to the sites within the same sampling area and finally according to season.

Lipids in Marine Ecosystems

Lipids provide the densest form of energy in marine ecosystems. They are also a solvent and absorption carrier for organic contaminants and thus can be drivers of pollutant bioaccumulation. Among the lipids, certain essential fatty acids and sterols are considered to be important determinants of ecosystem health and stability. Fatty acids and sterols are also susceptible to oxidative damage leading to cytotoxicity and a decrease in membrane fluidity. The physical characteristics of biological membranes can be defended from the influence of changing temperature, pressure, or lipid peroxidation by altering the fatty acid and sterol composition of the lipid bilayer. Marine lipids are also a valuable tool to measure inputs, cycling, and loss of materials. Their heterogeneous nature makes them versatile biomarkers that are widely used in marine trophic studies, often with the help of multivariate statistics, to delineate carbon cycling and transfer of materials. Principal components analysis has a strong following as it permits data reduction and an objective interpretation of results, but several more sophisticated multivariate analyses which are more quantitative are emerging too. Integrating stable isotope and lipid data can facilitate the interpretation of both data sets and can provide a quantitative estimate of transfer across trophic levels.

Gender differences in the immune system activities of sea urchin Paracentrotus lividus

In the immune system of vertebrates, gender-specific differences in individual immune competence are well known. In general, females possess more powerful immune response than males. In invertebrates, the situation is much less clear. For this purpose we have chosen to study the immune response of the two sexes of the echinoderm Paracentrotus lividus in pre- and post-spawning phases. The coelomic fluid from the echinoderms contains several coelomocyte types and molecules involved in innate immune defenses. In this article we report that the degree of immune responses in the P. lividus differs according to sex in both pre- and post-spawning phases. We found in all tests that females were more active than males. The results indicate that females possess a significant higher number of immunocytes consisting of phagocytes and uncolored spherulocytes. Since the immunological activity is mainly based on immunocytes, it was not surprising that females possessed the highest values of cytotoxicity and hemolysis activity and showed a greater ability to uptake neutral red and phagocyte yeasts cells, while the average number of ingested particles per active phagocyte was not significantly different. Furthermore, agglutinating activity was more evident in the coelomocyte lysate and coelomic fluid of females than in those of males. Finally we found that the acidic extract of female gonads possessed greater antimicrobial activity than that of male gonads. These results make it very likely that gender differences in the immune response are not restricted to vertebrates; rather, they are a general evolutionary phenomenon.