Cellular Prion Protein Expression in the Brain Tissue from Brucella ceti-Infected Striped Dolphins (Stenella coeruleoalba)

Brucella ceti, a zoonotic pathogen of major concern to cetacean health and conservation, is responsible for severe meningo-encephalitic/myelitic lesions in striped dolphins (Stenella coeruleoalba), often leading to their stranding and death. This study investigated, for the first time, the cellular prion protein (PrPc) expression in the brain tissue from B. ceti-infected, neurobrucellosis-affected striped dolphins. Seven B. ceti-infected, neurobrucellosis-affected striped dolphins, found stranded along the Italian coastline (6) and in the Canary Islands (1), were investigated, along with five B. ceti-uninfected striped dolphins from the coast of Italy, carrying no brain lesions, which served as negative controls. Western Blot (WB) and immunohistochemistry (IHC) with an anti-PrP murine monoclonal antibody were carried out on the brain parenchyma of these dolphins. While PrPc IHC yielded inconclusive results, a clear-cut PrPc expression of different intensity was found by means of WB analyses in the brain tissue of all the seven herein investigated, B. ceti-infected and neurobrucellosis-affected cetacean specimens, with two dolphins stranded along the Italian coastline and one dolphin beached in Canary Islands also exhibiting a statistically significant increase in cerebral PrPc expression as compared to the five Brucella spp.-negative control specimens. The significantly increased PrPc expression found in three out of seven B. ceti-infected, neurobrucellosis-affected striped dolphins does not allow us to draw any firm conclusion(s) about the putative role of PrPc as a host cell receptor for B. ceti. Should this be the case, an upregulation of PrPc mRNA in the brain tissue of neurobrucellosis-affected striped dolphins could be hypothesized during the different stages of B. ceti infection, as previously shown in murine bone marrow cells challenged with Escherichia coli. Noteworthy, the inflammatory infiltrates seen in the brain and in the cervico-thoracic spinal cord segments from the herein investigated, B. ceti-infected and neurobrucellosis-affected striped dolphins were densely populated by macrophage/histiocyte cells, often harboring Brucella spp. antigen in their cytoplasm, similarly to what was reported in macrophages from mice experimentally challenged with B. abortus. Notwithstanding the above, much more work is needed in order to properly assess the role of PrPc, if any, as a host cell receptor for B. ceti in striped dolphins

Immunohistochemical investigations on Brucella ceti-infected, neurobrucellosis-affected striped dolphins (Stenella coeruleoalba)

Bacteria of the genus Brucella cause brucellosis, an infectious disease common to humans as well as to terrestrial and aquatic mammals. Since 1994 several cases of Brucella spp. infection have been reported in marine mammals worldwide. Indeed, since human brucellosis ranks as one of the most common bacterial zoonotic infections on a global scale, it is necessary to increase our knowledge about it also in the marine environment. Brucella ceti, which is phenotypically similar to other smooth brucellae as B. abortus and B. melitensis, shares with the latter two the same surface antigens that are routinely used for the serological diagnosis of Brucella spp. infection. Marine mammal Brucella spp. infections are characterized by a pathogenicity similar to their terrestrial counterparts, with the occurrence of abortion, stillbirth and orchitis and an involvement of the host’s central nervous system (CNS), similarly to what happens in mankind. While sero-epidemiological data suggest that Brucella spp. infection is widespread globally, detecting Brucella spp.-associated antigens by immunohistochemistry (IHC) in tissues from infected animals is often troublesome. The present study was aimed at investigating, by means of IHC based upon the utilization of an anti-Brucella LPS monoclonal antibody (MAb), the CNS immunoreactivity (IR) shown by B. ceti-infected, neurobrucellosis-affected striped dolphins

Total and methylmercury residues in tuna-fish from the Mediterranean sea

This study was carried out to determine the current levels of total mercury and methylmercury in the muscle tissue of albacore (Thunnus alalunga) and bluefin tuna (Thunnus thynnus) caught in the Mediterranean sea with the purpose of ascertaining whether the concentrations exceeded the maximum level fixed by the European Commission Decision. Total mercury concentrations ranged from 0.84 to 1.45 mg kg(-1) w.w. (av. 1.17 mg kg(-1) w.w.) and from 0.16 to 2.59 mg kg(-1) (av. 1.18 mg kg(-1) w.w.) in the muscle of albacore and bluefin tuna, respectively. In 78.6% of albacore and in 61.1% of bluefin tuna analysed, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg = 1 micro g g(-1) wet wt). In the two species, mercury was present almost completely in the methylated form, with percentages between 77 and 100% (av. 91.3%) in albacore and between 75 and 100% (av. 91%) in bluefin-tuna. In order to assess the potential health impact, the estimated weekly intake was calculated. The estimated weekly intake was far above the established Provisional Tolerable Weekly Intake for both species.[...

Total and methylmercury residues in cartilagineous fish from Mediterranean Sea

Concentrations of mercury and methylmercury residues were determined in the muscle tissue of three cartilaginous fishes Chimaera monstrosa (ghostshark), Torpedo nobiliana (electric ray) and Myliobatis aquila (eagle ray) from the Mediterranean Sea. The highest mean levels of total mercury were detected in ghostshark (3.14 mg/kg wet weight), followed by electric ray (2.42 mg/kg wet weight), and eagle ray (0.83 mg/kg wet weight). Such a variability is influenced by quite a number of factors, among which size, fish ecology and feeding habits. The percentages of the methylated form to total mercury ranged from a minimum of 72% in eagle ray to a maximum of 83% in ghostshark. Relationship between specimen size and mercury and methylmercury concentrations were found in ghostshark species.[...

Relationship between total mercury concentration and fish size in two pelagic fish species: implications for consumer health

Total mercury concentrations were determined in different size classes of two pelagic fish species of great commercial importance, horse mackerel (Trachurus trachurus) and Mediterranean horse mackerel (Trachurus mediterraneus), to evaluate the relationship between total mercury concentration and fish size and to determine whether any differences might affect the quantitative assessment of mercury exposure for consumers. Mercury concentrations in horse mackerel and in Mediterranean horse mackerel were between 0.16 and 2.41 mu g g(-1) of weight wet (mean, 0.68 mu g g(-1)) and between 0.09 and 1.62 mu g g(-1) (mean, 0.51 mu g g(-1)), respectively. The regression curves revealed a significant relationship between mercury concentration and fish size (length and weight) for both species. Concentrations exceeding the proposed limit for human consumption were observed in 33.3% of the samples of both species and were associated with larger specimens. The consumption of the larger specimens could lead to an increase in mercury exposure for consumers. Estimated weekly intakes, calculated on the basis of concentrations relative to each size class, revealed a high exposure associated with the consumption of fish larger than 30 cm (horse mackerel, 11.63 to 20.16 mu g/kg of body weight; Mediterranean horse mackerel, 5.86 to 13.55 mu g/kg of body weight). An understanding of the factors leading to an increase in mercury exposure can help consumers make informed decisions about eating fish. [...

Eicosanoids in Healthy and Diseased Porcine Lungs: Immunohistochemical and Biochemical Investigations.

Eicosanoids derive from the metabolism of arachidonic acid and serve as intracellular and extracellular signals, which are able to affect a wide variety of biologic processes, including inflammation.We summarize herein our data about 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) dependent enzymatic pathways in healthy and diseased porcine lungs. In detail, the following pulmonary diseases were investigated: Metastrongylus spp.-induced porcine parasitic bronchopneumonia, chronic enzootic pneumonia caused by Mycoplasma hyopneumoniae (Mh), acute pleuropneumonia by Actinobacillus pleuropneumoniae (App) and interstitial pneumonia caused by Porcine Circovirus type 2 (PCV2).Pulmonary tissue samples from healthy controls and diseased pigs were collected from slaughtered (healthy controls, Metastrongylus spp. and Mh-infected pigs) or spontaneously died (App and PCV2-infected pigs) animals, and adequately processed for histopathology, immunohistochemistry (IHC) and biochemical investigations.IHC was carried out by using polyclonal goat antibodies anti-5-LOX (C-19, Santa Cruz Biotechnology, 1 in 500) and anti-COX-2 (C-20, Santa Cruz Biotechnology, 1 in 250).5-LOX and COX-2 dependent enzymatic pathways were further investigated by Western blotting analysis and enzymatic activity assays. Arachidonic acid metabolites (namely leukotriene B4 and prostaglandin E2) were also quantified (Leukotriene B4 EIA kit™; Prostaglandin E2 EIA kit™; Cayman Chemical Company, USA).Our results confirm that 5-LOX and COX-2 are constitutively expressed in healthy porcine lungs. Furthermore, our data suggest that both investigated enzymatic pathways are significantly modified and/or over-expressed in porcine lungs affected by acute and chronic pneumonia caused by different etiological agents. Remarkably, 5-LOX- dependent biochemical pathway – which has been poorly investigated in veterinary medicine and is not inhibited by nonsteroidal anti-inflammatory drugs – seems to strongly participates in the acute and chronic inflammatory response in porcine pneumonia.[...

Total mercury in muscle of benthic and pelagic fish from the south Adriatic sea (Italy)

Total mercury concentrations were measured from the muscle of different kinds of fish: yellow gurnard (Trigla lucerna), red gurnard (Aspitrigla cuculus) red fish (Helicolenus dactylopterus), skate spp. (Raje spp.), goldline (Sarpa salpa), atlantic bonito (Sarda sarda), mackerel (Scomber scombrus), chub mackerel (Scomber japonicus) caught in the South Adriatic Sea (south Italy) in the period June/August 1995. The highest total mercury levels were found in the benthic marine organisms and particularly in skates (Raje spp.) whose values ranged from 0.05 to 2.65 mg/kg wet wt with a mean value of 1.02 mg/kg wet wt. As for pelagic species, the highest mean levels were observed in Atlantic bonito (0.34 mg/kg wet wt), while in goldline the mean content of total mercury was the lowest (0.07 mg/kg wet wt). According to the rules in force (Official Journal of the European Communities 1994) 53% of skate and Atlantic bonito samples showed concentrations exceeding the peak value of 1 mg/kg, while for the other species, only 28% of samples exceeded the peak value fixed at 0.5 mg/kg. Correlations between total mercury concentration and specimen weight were evident in all examined species except for goldline and skates.[...

Total mercury and methylmercury in tuna fish and sharks from the south Adriatic sea

Total mercury and metylmercury concentrations were measured in tuna fish and sharks from the South Adriatic Sea. The highest mean levels of total mercury were found in Squalus acanthias (6.5 mg/Kg w.w.). In the other species mean mercury levels were notably lower (0.46 mg/Kg w.w. for Auxis rochey; 0.38 mg/Kg w.w. for Prionace glauca). Twenty-two percent of the Auxis rochei samples exceed the legal Italian limit (0.50 mg/Kg w.w.) as specified by the European Commission Directive. No sample of Prionace glauca exceed the legal limit of 1 mg/Kg wet.[...