1,721,001 research outputs found
Estrogenic compounds as exogenous modulators of physiological functions in molluscs: Signaling pathways and biological responses
No full textMolluscs 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 17β-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
Invertebrate Models for Investigating the Impact of Nanomaterials on Innate Immunity: The Example of the Marine Mussel Mytilus spp.
No full textInvertebrate Models for Investigating the Impact of Nanomaterials on Innate Immunity: The Example of the Marine Mussel Mytilus spp.
Full text linkEvaluating the interactions of nanomaterials (NMs) with the immune system is becoming an
essential part of assessing nanosafety, not only for human health, but also for organisms living in different
environments. The interactions between NMs and the components of the immune system in
wildlife have been recently intensively investigated. Invertebrates represent more than 90% of animal
species and are widespread in all environments, where they are subjected to a wide range of stressors.
Despite invertebrates lack an adaptive immunity, they have developed a potent and complex innate
immune system showing many commonalities to that of vertebrates. Conservation of the main mechanisms
of innate immunity may greatly help understanding the possible interactions of NMs with the immune system
across different taxa. However, the utilization of invertebrate models for immunosafety studies requires a thorough basic
knowledge on the physiological regulation of the immune response of the tested species, together with information on particle
behavior in the receiving environment, as well as routes of exposure in different cells and organisms. In this work,
available data on the effects of NMs on the immune system of invertebrates are summarized. In particular, the results obtained
in the marine bivalve, the mussel Mytilus, are summarized, demonstrating that mussel immune cells, the haemocytes,
represent a suitable model for investigating the impact of NMs on innate immunity. These results underline how the
utilization of invertebrate models represents a promising field for designing environmentally safer, "green" nanomaterials
Seasonal variability of different biomarkers in mussels (Mytilus galloprovincialis) farmed at different sites of the Gulf of La Spezia, Ligurian sea, Italy
No full textMussels (Mytilus spp.) are worldwide utilized in marine biomonitoring by a multi-biomarker approach. However, for a correct interpretation of different biomarker responses, information is needed on their natural seasonal variability due to environmental/physiological factors. In this work, the seasonal variations of different biomarkers were investigated in M. galloprovincialis from 4 different sites from the gulf of La Spezia (Ligurian sea, Italy), an intensive rearing area in the north-western Mediterranean near La Spezia harbor, an important commercial and touristic port. Lysosomal membrane stability-LMS, stress on stress-SoS, phagocytosis, tissue metallothionein-MT content, oxidative stress related enzyme activities (GST, catalase), and nitric oxide (NO) production were evaluated. The results underline the importance of LMS and SoS as core descriptors of the mussel health status in relation to seasonal variations in temperature and reproduction. These data represent the baseline information for ongoing biomonitoring studies related to dredging activities in this area
Physiological Roles of Serotonin in Bivalves: Possible Interference by Environmental Chemicals Resulting in Neuroendocrine Disruption
No full textInteractive effects of nanoparticles with other contaminants in aquatic organisms: Friend or foe?
Full text linkThe 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
Soluble mediators of innate immunity in annelids and bivalve mollusks: A mini-review
No full textAnnelids and mollusks, both in the superphylum of Lophotrochozoa (Bilateria), are important ecological groups, widespread in soil, freshwater, estuarine, and marine ecosystems. Like all invertebrates, they lack adaptive immunity; however, they are endowed with an effective and complex innate immune system (humoral and cellular defenses) similar to vertebrates. The lack of acquired immunity and the capacity to form antibodies does not mean a lack of specificity: invertebrates have evolved genetic mechanisms capable of producing thousands of different proteins from a small number of genes, providing high variability and diversity of immune effector molecules just like their vertebrate counterparts. This diversity allows annelids and mollusks to recognize and eliminate a wide range of pathogens and respond to environmental stressors. Effector molecules can kill invading microbes, reduce their pathogenicity, or regulate the immune response at cellular and systemic levels. Annelids and mollusks are “typical” lophotrochozoan protostome since both groups include aquatic species with trochophore larvae, which unite both taxa in a common ancestry. Moreover, despite their extensive utilization in immunological research, no model systems are available as there are with other invertebrate groups, such as Caenorhabditis elegans or Drosophila melanogaster, and thus, their immune potential is largely unexplored. In this work, we focus on two classes of key soluble mediators of immunity, i.e., antimicrobial peptides (AMPs) and cytokines, in annelids and bivalves, which are the most studied mollusks. The mediators have been of interest from their first identification to recent advances in molecular studies that clarified their role in the immune response
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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