Specificity of innate immunity in bivalves: a lesson from bacteria

Bivalves are a relevant ecological group, widespread in freshwater, estuarine, and marine ecosystems, with many edible species, such as oysters, mussels, and clams. Bivalves are endowed with an effective and complex innate immune system (humoral and cellular defenses). Bivalve immunity displays a wide variety of sensitive receptors, selective effectors, and synergistic genetic regulatory networks that afford protection in a fluctuating environment.As filter feeders, bivalves accumulate large numbers of microorganisms, mainly bacteria, that can either establish a commensal relationship with the host or proliferate and invade soft tissues, resulting in a high mortality of bivalve juveniles and adults. In this framework, understanding the relationship between the bivalve immune system and bacteria has important implications not only for the protection of economically important species but also for human health concerns. Available data underlying the specificity of bivalve immune responses to bacterial challenges will be summarized. \ua92016 Elsevier Inc. All rights reserved

Effects of nanomaterials on marine invertebrates

The development of nanotechnology will inevitably lead to the release of consistent amounts of nanomaterials (NMs) and nanoparticles (NPs) into marine ecosystems. Ecotoxicological studies have been carried out to identify potential biological targets of NPs, and suitable models for predicting their impact on the health of the marine environment. Recent studies in invertebrates mainly focused on NP accumulation and sub-lethal effects, rather than acute toxicity. Among marine invertebrates, bivalves represent by large the most studied group, with polychaetes and echinoderms also emerging as significant targets of NPs. However, major scientific gaps still need to be filled. In this work, factors affecting the fate of NPs in the marine environment, and their consequent uptake/accumulation/toxicity in marine invertebrates will be summarized. The results show that in different model species, NP accumulation mainly occurs in digestive tract and gills. Data on sub-lethal effects and modes of action of different types of NPs (mainly metal oxides and metal based NPs) in marine invertebrates will be reviewed, in particular on immune function, oxidative stress and embryo development. Moreover, the possibility that such effects may be influenced by NP interactions with biomolecules in both external and internal environment will be introduced. In natural environmental media, NP interactions with polysaccharides, proteins and colloids may affect their agglomeration/aggregation and consequent bioavailability. Moreover, once within the organism, NPs are known to interact with plasma proteins, forming a protein corona that can affect particle uptake and toxicity in target cells in a physiological environment. These interactions, leading to the formation of eco-bio-coronas, may be crucial in determining particle behavior and effects also in marine biota. In order to classify NPs into groups and predict the implications of their release into the marine environment, information on their intrinsic properties is clearly insufficient, and a deeper understanding of NP eco/bio-interactions is required

Estrogenic compounds as exogenous modulators of physiological functions in molluscs: Signaling pathways and biological responses

Molluscs have been widely utilized to evaluate the effects of estrogenic compounds, one of the most widespread classes of Endocrine Disrupting Chemicals-EDCs. However, knowledge on steroid signaling and metabolism in molluscs has considerably increased in the last decade: from these studies, a considerable debate emerged on the role of 'natural' steroids in physiology, in particular in reproduction, of this invertebrate group. In this work, available information on the effects and mechanisms of action of estrogens in molluscs will be reviewed, with particular emphasis on bivalves that, widespread in aquatic ecosystems, are most likely affected by exposure to estrogenic EDCs. Recent advances in steroid uptake and metabolism, and estrogen receptors-ERs in molluscs, as well as in estrogen signaling in vertebrates, will be considered. The results so far obtained with 17\u3b2-estradiol and different estrogenic compounds in the model bivalve Mytilus spp., demonstrate specific effects on immune function, development and metabolism. Transcriptomic data reveal non genomic estrogen signaling pathways in mussel tissues that are supported by new observations at the cellular level. In vitro and in vivo data show, through independent lines of evidence, that estrogens act through non-genomic signaling pathways in bivalves. In this light, regardless of whether molluscs synthesize estrogens de novo or not, and despite their ERs are not directly activated by ligand binding, estrogens can interact with multiple signaling components, leading to modulation of different physiological functions. Increasing knowledge in endocrine physiology of molluscs will provide a framework for a better evaluation and interpretation of data on the impact of estrogenic EDCs in this invertebrate group

Interactive effects of nanoparticles with other contaminants in aquatic organisms: Friend or foe?

none3The increasing production and use of nanoparticles (NPs) will lead to their release into the aquatic environment, posing a potential threat to the health of aquatic organisms. Both in the water phase and in the sediments NPs could mix and interact with other pollutants, such as organic xenobiotics and heavy metals, leading to possible changes in their bioavailability/bioconcentration/toxicity. However, whether these interactive effects may lead to increased harmful effects in marine organisms is largely unknown. In this work, available data mainly obtained on carbon based NPs and n-TiO2, as examples of widespread NPs, in aquatic organisms are reviewed. Moreover, data are summarized on the interactive effects of n-TiO2 with 2,3,7,8-TCDD and Cd(2+), chosen as examples of common and persistent organic and inorganic contaminants, respectively, in the model marine bivalve Mytilus. The results reveal complex and often unexpected interactive responses of NPs with other pollutants, depending on type of contaminant and the endpoint measured, as well as differences in bioaccumulation. The results are discussed in relation with data obtained in freshwater organisms. Overall, information available so far indicate that interactive effects of NPs with other contaminants do not necessarily lead to increased toxicity or harmful effects in aquatic organisms.openCanesi, L; Ciacci, C; Balbi, TCanesi, L; Ciacci, C; Balbi,

Guarantees and Collaterals Value in NPLs

Abstract The burst of the subprime mortgage crisis affected on a large scale the Italian real estate industry. The Italian real estate market underwent and is still undergoing a severe stagnancy due to the credit crunch worsened by the banking system and the resulting lack of liquidity. In financing real estate property investments, security packages play an extremely important role and guarantees have become a major tool for risk management and financial innovation in order to facilitate credit enhancement and hedging of risks. In this context the evaluation of guarantees and collaterals becomes extremely important. A robust measure of the value of collaterals is more than a key issue in times of financial crisis, when the value of the guarantees is questioned. Aim of this paper is to investigate, on a sample of 89 foreclosures, whether the collaterals were overestimated and the mortgage lending value represents a robust measure of the mortgage underlying guarantee

Temporal variation of Skeletonema community composition from a long-term time series in Narragansett Bay identified using high-throughput DNA sequencing

Phytoplankton species cannot always be identified by their morphology using light microscopy, which makes inferring the ecological and biogeochemical importance of individual species a difficult task. Here, a combination of microscopy and high-throughput DNA sequencing was used to examine morphologically cryptic and pseudo-cryptic species in the diatom genus Skeletonema from the Long-Term Plankton Time Series in Narragansett Bay (NBay), where Skeletonema is ecologically important, comprising up to 99% of microplankton cells in surface waters. The 28S rDNA from mock phytoplankton communities comprising known species was amplified and sequenced using newly developed Skeletonema-specific primers. The relative abundances of species in the sequence data did not match expected abundances, suggesting that 28S copy number can vary greatly, even among closely related diatom species. The 28S rDNA was also amplified from 75 field samples collected from 2008 to 2013. A total of 7 Skeletonema species were identified, including 5 newly detected species from NBay. Skeletonema species composition was highly seasonal and significantly correlated with water temperature. Winter–spring and summer–autumn communities were significantly different and characterized by low and high species richness, respectively. Species abundance during winter–spring was quantified by combining sequence data with light microscopy counts, revealing Skeletonema marinoi as the numerically dominant species during the winter–spring bloom. Seasonal variation in Skeletonema composition suggests that, although morphologically similar, species in this genus are likely adapted to different environmental conditions, raising the possibility that species composition of this important bloom-forming genus may shift as water temperatures in NBay increase due to anthropogenic influences

Physiological Roles of Serotonin in Bivalves: Possible Interference by Environmental Chemicals Resulting in Neuroendocrine Disruption

Contaminants of Emerging Concerns (CECs) are defined as chemicals not commonly monitored in aquatic ecosystems, but with the potential to cause adverse effects on biota. CECs include Endocrine Disrupting Chemicals (EDCs) and Neuro-Endocrine disruptors (NEDs) of vertebrates. However, most invertebrates only rely on neuroendocrine systems to maintain homeostatic processes. Although conserved neuroendocrine components have been characterized in ecologically relevant groups, limited knowledge on invertebrate neuroendocrinology makes it difficult to define EDCs and NEDs in most species. The monoamine serotonin (5-hydroxytryptamine, 5-HT) acts both as a neurotransmitter and as a peripheral hormone in mammals. In molluscs, 5-HT is involved in multiple physiological roles and molecular components of the serotonergic system have been identified. This review is focused on the effects of CECs on the serotonergic system of bivalve molluscs. Bivalves are widespread in all aquatic environments, estuarine and coastal areas in particular, where they are exposed to a variety of chemicals. In bivalves, 5-HT is involved in gametogenesis and spawning, oocyte maturation and sperm motility, regulates heart function, gill ciliary beating, mantle/siphon function, the ‘‘catch’’ state of smooth muscle and immune responses. Components of 5-HT transduction (receptors and signaling pathways) are being identified in several bivalve species. Different CECs have been shown to affect bivalve serotonergic system. This particularly applies to antidepressants, among the most commonly detected human pharmaceuticals in the aquatic environment. In particular, selective serotonin reuptake inhibitors (SSRIs) are frequently detected in seawater and in bivalve tissues. Information available on the effects and mechanisms of action of SSRIs on the serotonergic system of adult bivalves is summarized. Data are also reported on the effects of CECs on development of neuroendocrine pathways of early larval stages, in particular on the effects of model EDCs in the marine mussel Mytilus galloprovincialis. Overall, available data point at the serotonergic system as a sensitive target for neuroendocrine disruption in bivalves. The results contribute drawing Adverse Outcome Pathways (AOPs) for model EDCs and SSRIs in larvae and adults. However, basic research on neuroendocrine signaling is still needed to evaluate the potential impact of neuroendocrine disruptors in key invertebrate groups of aquatic ecosystems

Il valore cauzionale e il valore di vendita forzata nel mercato del credito fondiario e delle aste immobiliari

In the last ten years, in Italy, there has been a steady increase in enforcement proceedings which culminate in real estate auction. There has been a reduction of proceedings in the last two years, this turnaround was not able to absorb the previous oversupply, as demand steadily declining. Sale timing and discounts from the list prices have increased. Few researchers have studied the Italian real estate forced sale market until now, because of the reduced volume of sales and the small number of stakeholders. This type of market and its balance between supply and demand is an interesting and innovative study. This research analyzes the discount-premium in auction market. It calculates the difference between the estimated value of the property, which coincides with the listing price, and the price of final adjudication. This difference helps us to construe more accurately the meaning of forced sales value in relation to the market value, which has not been well defined yet in literature, neither the national nor the international one

SIGNAL GROUPING FOR CONDITION MONITORING OF NUCLEAR POWER PLANT COMPONENTS

International audienceThe present work investigates the possibility of building a condition monitoring model by splitting the usually very large number of signals measured by the sensors into subgroups and building a specialized model for each subgroup. Different criteria are considered for selecting the signal groups, such as the location of the measurements (i.e., signals measured in the same area of the plant belong to the same group) and their correlation (i.e., correlated signals are grouped together). A real case study concerning 48 signals selected between those used to monitor the reactor coolant pump of a Pressurized Water Reactor (PWR) is considered in order to verify the monitoring performance of different grouping criteria. Performance metrics measuring accuracy, robustness and spill-over effect have been considered in the evaluation. Key Words: Condition Monitoring, Empirical Modeling, Power Plants, Safety Critical Nuclear Instrumentation, Autoassociative models

Genetic Algorithm-based Wrapper Approach for Grouping Condition Monitoring Signal of Nuclear Power Plant Components

Equipment condition monitoring of nuclear power plants requires to optimally group the usually very large number of signals and to develop for each identified group a separate condition monitoring model. In this paper we propose an approach to optimally group the signals. We use a Genetic Algorithm (GA) for the optimization of the groups; the decision variables of the optimization problem relate to the composition of the groups (i.e., which signals they contain) and the objective function (fitness) driving the search for the optimal grouping is constructed in terms of quantitative indicators of the performances of the condition monitoring models themselves: in this sense, the GA search engine is a wrapper around the condition monitoring models. A real case study is considered, concerning the condition monitoring of the Reactor Coolant Pump (RCP) of a Pressurized Water Reactor (PWR). The optimization results are evaluated with respect to the accuracy and robustness of the monitored signals estimates. The condition monitoring models built on the groups found by the proposed approach outperform the model which uses all available signals, whereas they perform similarly to the models built on groups based on signal correlation. However, these latter do not guarantee the robustness of the reconstruction in case of abnormal conditions and require to a priori fix characteristics of the groups, such as the desired minimum correlation value in a group