Gioele Capillo

Evaluation of Functionality and Biological Responses of Mytilus galloprovincialis after Exposure to Quaternium-15 (Methenamine 3-Chloroallylochloride).

Although the irritant effects of quaternium-15 have been established, little is known about the toxicological consequences induced by this xenobiotic on aquatic invertebrates. The present article reports toxicological, histological and physiological effects of quaternium-15 following the exposure of Mytilus galloprovincialis for 18 days at three different concentrations (0.1, 1.0 and 2.0 mg/L). The results demonstrate that at higher concentrations histological damages to M. galloprovincialis gills occur, like melanosis, light exfoliations, increase of mucus production and infiltrative inflammation. In addition digestive gland cells of M. galloprovincialis, were not able to perform the regulation volume decrease (RVD) owing to osmotic stress following the exposure to the preservative. Overall, this first study on quaternium-15 highlights that it can jeopardize both the morphology and vital physiological processes in marine invertebrates, depending on the duration of exposure and the concentration of the preservative, indicating that further studies are necessary to increase our knowledge about the effects of this substance, commonly added to our products of daily use.

The structure of the gas bladder of the spotted gar, Lepisosteus oculatus

We report here on the macroscopic, light microscopic, and electron microscopic structure of the gas bladder (GB) of the spotted gar, Lepisosteus oculatus. The GB opens into the pharynx, dorsal to the opening of the oesophagus, through a longitudinal slit bordered by two glottal ridges. Caudal to the ridges, the GB is an elongated sac divided into a central duct and right and left lobes. The lobes are formed by a cranio‐caudal sequence of large air spaces that open into the central duct. The structure of the GB is that of a membranous sac supported by a system of septa arising from the walls of a central duct. The septa contain variable amounts of striated and smooth muscle might function to maintain the bladder shape and in providing contractile capabilities. The presence of muscle cells, nerves, and neuroepithelial cells in the wall of the GB strongly suggests that GB function is tightly regulated. The central duct and the apical surface of the thickest septa are covered by mucociliated epithelium. Most of the rest of the inner bladder surface is covered by a respiratory epithelium which contains goblet cells and a single type of pneumocyte. These two cell types produce surfactant. The respiratory barrier contains thick areas with fibrillar material and cell prolongations, and thin areas that only contain basement membrane material between the capillary wall and the respiratory epithelium. Lungs and GBs share many anatomical and histological features. There appears to be no clear criterion for structural distinction between these two types of respiratory organs. J. Morphol. 276:90–101, 2015.

Assessment of Electrolytes and Metals Profile of the Faro Lake (Capo Peloro Lagoon, Sicily, Italy) and Its Impact on Mytilus galloprovincialis

Faro Lake is a coastal meromictic lagoon with singular characteristics in the Mediterranean (Messina, Sicily – Italy). It is part of the Natural Oriented Reserve of Capo Peloro (38° 15′ 57″ N; 15° 37′ 50″ E). In this area, traditional mollusc farming activity persists, producing ‘autochthonous’ mussels. This study reports of the Mytilus galloprovincialis haemolymph chemical profile and water variables determination of 1 year‐lasted survey (April 2016 – March 2017). The determinations of electrolytes (Na+, Cl–, K+, Ca2+, Mg2+, P inorganic) and heavy metals in both Faro lake water and haemolymph have been carried out. Heavy metals are elements with high density and are quite toxic in low concentrations, such as Aluminum (Al), Arsenic (As), Cobalt (Co), Chrome (Cr), Copper (Cu), Iron (Fe), Magnesium (Mg), Manganese (Mn), Lead (Pb), Tin (Sn), Zinc (Zn). Heavy metals toxicity depends, principally, on bioaccumulation processes. M. galloprovincialis is a good bio‐indicator, ideal for assess levels of environmental pollution thanks to its biological, ecological and physiological characteristics. The results of this study showed a typical fluctuation range in haemolymph and water parameters, related to the water ones; chemical‐physical parameters affected the ions (electrolytes and metals) levels in some period of the year. The study reports the interactions between biotic (Mytilus galloprovincialis) and abiotic (water parameters) components of Faro Lake, and creates reference data for further future study on the same area or on similar ones.

Identification and distribution of neuronal nitric oxide synthase and neurochemical markers in the neuroepithelial cells of the gill and the skin in the giant mudskipper, Periophthalmodon schlosseri

Mudskippers are amphibious fishes living in mudflats and mangroves. These fishes hold air in their large buccopharyngeal-opercular cavities where respiratory gas exchange takes place via the gills and higher vascularized epithelium lining the cavities and also the skin epidermis. Although aerial ventilation response to changes in ambient gas concentration has been studied in mudskippers, the localization and distribution of respiratory chemoreceptors, their neurochemical coding and function as well as physiological evidence for the gill or skin as site for O2 and CO2 sensing are currently not known. In the present study we assessed the distribution of serotonin, acetylcholine, catecholamines and nitric oxide in the neuroepithelial cells (NECs) of the mudskipper gill and skin epithelium using immunohistochemistry and confocal microscopy. Colocalization studies showed that 5-HT is coexpressed with nNOS, Na+/K+-ATPase, TH and VAChT; nNOS is coexpressed with Na+/K+-ATPase and TH in the skin. In the gill 5-HT is coexpressed with nNOS and VAhHT and nNOS is coexpressed with Na+/K+-ATPase and TH. Acetylcholine is also expressed in chain and proximal neurons projecting to the efferent filament artery and branchial smooth muscle. The serotonergic cells c labeled with VAChT, nNOS and TH, thus indicating the presence of NEC populations and the possibility that these neurotransmitters (other than serotonin) may act as primary transmitters in the hypoxic reflex in fish gills. Immunolabeling with TH antibodies revealed that NECs in the gill and the skin are innervated by catecholaminergic nerves, thus suggesting that these cells are involved in a central control of branchial functions through their relationships with the sympathetic branchial nervous system. The Na+/K+-ATPase in mitochondria-rich cells (MRCs), which are most concentrated in the gill lamellar epithelium, is colabeled with nNOS and associated with TH nerve terminals. TH-immunopositive fine varicosities were also associated with the numerous capillaries in the skin surface and the layers of the swollen cells. Based on the often hypercapnic and hypoxic habitat of the mudskippers, these fishes may represent an attractive model for pursuing studies on O2 and CO2 sensing due to the air-breathing that increases the importance of acid/base regulation and the O2-related drive including the function of gasotransmitters such as nitric oxide that has an inhibitory (regulatory) function in ionoregulation.

Confocal imaging of autonomic preganglionic neurons in the spinal cord of the caecilian Typhlonectes natans (Amphibia: Gymnophiona)

Little is known about the spinal sympathetic organization in the caecilian amphibians. We examined for the first time the location of sympathetic preganglionic neurons (SPNs) in the spinal cord using a panel of specific markers expressed in SPNs. The SPNs of anuran amphibians form two cell columns segregated mainly in the lateral and medial marginal areas of the central gray matter. In the caecilian Typhlonectes natans immunoreactivity for galanin and ChAT is found in most laterally arranged neurons lying in spinal segments 2-7. They are encircled by TH- and nNOS-immunoreactive nerve fibers. These neurons might project specifically to a population of adrenergic sympathetic postganglionic neurons in paravertebral ganglia and/or non-adrenergic sympathetic postganglionic neurons in the celiac ganglia. However the segmental restriction and target specificity of the neurons of the species studied are not known. As mucous and granular glands in the dermis may represent one of the peripheral targets of the adrenergic ganglion cells and reflect the prominent preganglionic cell columns, an immunohistochemical study was done also on these glands. Retrograde-tracing studies are, however, needed to study the segmental localization of the preganglionic neurons and their projections to the postganglionic neurons in sympathetic ganglia.

Immunohistochemical colocalization of G protein alpha subunits and 5-HT in the rectal gland of the cartilaginous fish Scyliorhinus canicula

Serotonin [5‐hydroxytryptamine (5‐HT)] is an important neuromodulator involved in a wide range of physiological functions. The effects of serotonin are mediated by an extended family of receptors coupled to multiple heterotrimeric G‐proteins, associated with cellular membrane. G proteins connect receptors to effectors and thus trigger intracellular signaling pathways. These cellular processes several regulate systemic functions such as embryonic development, gonadal development, learning and memory, and organismal homeostasis. Generally, elasmobranch fish dwell a hypersaline environment and utilize a specialized extrarenal salt secreting organ, the rectal gland, to face ionic homeostasis. In this study in addition to the morphological, histochemical and immunohistochemical description of the Scyliorhinus canicula rectal gland, for the first time, the presence of serotonin (5‐HT), and distribution of different types of G protein alpha subunits (Gα o, Gα q/11, and Gα s/olf) has been investigated in the rectal gland epithelium by confocal immunofluorescence techniques. Colocalization G proteins and 5‐HT in the secretory epithelium of the gland suggests serotonin acts as a hormone and involves G proteins in an autocrine‐paracrine control of rectal gland homeostasis.

Evaluation of Water Variables in No-Take Zone of Ustica Marine Protected Area (Southern Tyrrhenian Sea)

In this research, the seasonal fluctuations of the main water variables in the no-take area (A zone) of the Ustica MPA were investigated. This study aims to monitor the water quality of the Ustica MPA, to analyze all the hydrological parameters useful to the physical-chemical characterization of water and to use TRIX index to characterize the trophic level of the coastal marine area. The final results shown that Ustica is an area of relevant environmental and ecological value and is a good example of a Marine Protected Area, which is not excessively affected by the human presence even during the touristic season. This study represents the first records based on well-organized protocol in order to assess water column characteristics of the studied area. This paper could be used as a reference document for future studies regarding the same or similar areas.

Returning of Hippocampus hippocampus (Linnaeus, 1758) (Syngnathidae) in the Faro Lake – oriented Natural Reserve of Capo Peloro, Italy

Abstract This study reports the returning of the seahorse in the Faro Lake and the most recent finding in a brackish coastal Mediterranean lagoon. After about 50 years from the first documented occurrence of Hippocampus hippocampus (Linnaeus, 1758) within the “Capo Peloro Lagoons”, North East Sicily, two adult specimens were observed alive in 2015. During that time, until the present rediscovery, the species was not recorded in biological studies and censuses for the area. This paper increases the knowledge about both the threatened seahorse species and the Natural Oriented Reserve of Capo Peloro. Graphical Abstract

In vivo effects of PCB-126 and genistein on vitellogenin expression in zebrafish

Abstract In this study, the vitellogenin (Vtg) modulation by genistein and polychlorinated biphenyl-126 (PCB-126) exposure in zebrafishes has been investigated. Both PCB-126 and genistein have been identified as aquatic pollutants and can further increase estrogenicity of waterways. Vtg is egg yolk precursor protein release by the hepatocytes during vitellogenesis. This process occurs normally in the hepatocytes in response to the activation with the estrogens such as 17-β-estradiol. Our immunohistochemical findings showed a Vtg expression that increases at 12 h and at 72 h in the liver of treated fishes with both PCB-126 and genistein, individually and in combination. Furthermore, for the first time, also hepatic stellate cells (HSC) in the liver parenchyma were strongly positive for vitellogenin.

Mucosal immune parameters, immune and antioxidant defence related genes expression and growth performance of zebrafish (Danio rerio) fed on Gracilaria gracilis powder

Abstract In the present study zebrafish (Danio rerio) has been used as model organism to establish the effects of dietary supplementation of Gracilaria gracilis powder (GP) on mucosal and innate immune parameters, antioxidant enzymes, and growth. In order to establish these features, zebrafish were fed for eight weeks with experimental diets containing different levels of Red algae, 0.25, 0.5 and 1% of GP; also, a group was fed with control diet. At the end of the experimental period the antioxidant superoxide dismutase and catalase (SOD, CAT) genes expression, interleukin 1 beta (il‐1&bgr;), lysozyme (LYZ), tumor necrosis factor alpha (TNF‐&agr;) for immune‐related genes expression, total immunoglobulin (Ig), total protein, alkaline phosphatase (ALP) activity for innate immune parameters, and growth performance have been established. The GP dietary supplementation showed differences in SOD and CAT expression in zebrafish whole body respect to the control group. Non‐signifcant differences were noticed among the different groups in case of TNF‐&agr;, LYZ and il‐1expression (P > 0.05). The skin mucus total Ig and total protein in the group fed on 1% of GP were significantly higher respect to control group (P < 0.05). 0.25 and 0.5% of GP dietary supplementation significantly enhanced skin mucus ALP activity levels (P < 0.05). No significant differences were recorded for growth performances among groups (P > 0.05). The results obtained in the present study revealed that G. gracilis could be takes in account as fishes diet supplementation for its immune system stimulants effects. HighlightsGracilaria gracilis, as supplement in fish diet, influences mucosal immune parameters in Danio rerio.Gracilaria gracilis, as supplement in fish diet, affects on growth in Danio rerio.Gracilaria gracilis, as supplement in fish diet, affects on antioxidant enzymes in Danio rerio.