19 resultados para Listeria spp
Resumo:
We analysed concentrations of cadmium, lead, mercury and selenium in blood from males and females of the 2 sibling species of giant petrels, the northern Macronectes halli and the southern M. giganteus, breeding sympatrically at Bird Island (South Georgia, Antarctica). Blood samples were collected in 1998 during the incubation period, from 5 November to 10 December. Between species, cadmium and lead concentrations were significantly higher for northern than for southern giant petrels, which probably resulted from northern giant petrels wintering in more polluted areas (mainly on the Patagonian Shelf and Falkland Islands) compared to southern giant petrels (wintering mainly around South Georgia and the South Sandwich Islands). Between sexes, cadmium concentrations were significantly higher for females than for males in both species, corresponding to the more pelagic habits of females compared to the more scavenging habits of males. Lead and cadmium concentrations in circulating blood decreased significantly over the incubation period, suggesting that when breeding at Bird Island, exposure to the source of pollution had ended, and these metals had been cleared from the blood and excreted, or rapidly transferred to other tissues. Association of lead and cadmium with a common source of pollution was further corroborated by a significant positive correlation between the levels of the 2 elements found. Mercury levels were similar between the species, but showed an opposite trend between sexes, with males showing higher levels than females in northern giant petrels, and the opposite was true in southern giant petrels, with no changes throughout incubation. Selenium levels were similar between sexes, but significantly greater for northern than for southern giant petrels. Moreover, there was a significant increase in the selenium levels over the incubation period in northern giant petrels. Age of adult birds did not affect metal concentrations. Coefficients of variation of metal levels were consistently lower for northern than for southern giant petrels, particularly for mercury, suggesting that the former species is more dietary specialised than the latter. Contaminant analyses, when combined with accurate information on seabird movements, obtained through geolocation or satellite tracking, help us to understand geographic variation of pollution in the marine environment.
Resumo:
Marine microorganisms, including Aeromonas, are a source of compds. for drug development that have generated great expectations in the last decades. Aeromonas infections produce septicemia, and ulcerative and haemorrhagic diseases in fish. Among the pathogenic factors assocd. with Aeromonas, the lipopolysaccharides (LPS), a surface glyconconjugate unique to Gram-neg. bacteria consisting of lipid A (lipid anchor of the mol.), core oligosaccharide and O-specific polysaccharide (O antigen), are key elicitors of innate immune responses. The chem. structure of these three parts has been characterized in Aeromonas. Based on the high variability of repeated units of O-polysaccharides, a total of 97 O-serogroups have been described in Aeromonas species, of which four of them (O:11; O:16; O:18 and O:34) account for more than 60% of the septicemia cases. The core of LPS is subdivided into two regions, the inner (highly conserved) and the outer core. The inner core of Aeromonas LPS is characterized by the presence of 3-deoxy-d-manno-oct-2-ulosonic (ketodeoxyoctonic) acid (Kdo) and l-glycero-d-manno-Heptoses (l,d-Hep), which are linked to the outer core, characterized by the presence of Glc, GlcN, Gal, and GalNAc (in Aeromonas salmonicida), d,d-Hep (in Aeromonas salmonicida), and l,d-Hep (in Aeromonas hydrophila). The biol. relevance of these differences in the distal part of the outer core among these species has not been fully assessed to date. The inner core is attached to the lipid A, a highly conserved structure that confers endotoxic properties to the LPS when the mol. is released in blood from lysed bacteria, thus inducing a major systemic inflammatory response known as septic or endotoxic shock. In Aeromonas salmonicida subsp. salmonicida the Lipid A components contain three major lipid A mols., differing in acylation patterns corresponding to tetra-, penta- and hexa-acylated lipid A species and comprising of 4'-monophosphorylated β-2-amino-2-deoxy-d-glucopyranose-(1→6)-2-amino-2-deoxy-d-glucopyranose disaccharide. In the present review, we discuss the structure-activity relationships of Aeromonas LPS, focusing on its role in bacterial pathogenesis and its possible applications.
Resumo:
Marine microorganisms, including Aeromonas, are a source of compds. for drug development that have generated great expectations in the last decades. Aeromonas infections produce septicemia, and ulcerative and haemorrhagic diseases in fish. Among the pathogenic factors assocd. with Aeromonas, the lipopolysaccharides (LPS), a surface glyconconjugate unique to Gram-neg. bacteria consisting of lipid A (lipid anchor of the mol.), core oligosaccharide and O-specific polysaccharide (O antigen), are key elicitors of innate immune responses. The chem. structure of these three parts has been characterized in Aeromonas. Based on the high variability of repeated units of O-polysaccharides, a total of 97 O-serogroups have been described in Aeromonas species, of which four of them (O:11; O:16; O:18 and O:34) account for more than 60% of the septicemia cases. The core of LPS is subdivided into two regions, the inner (highly conserved) and the outer core. The inner core of Aeromonas LPS is characterized by the presence of 3-deoxy-d-manno-oct-2-ulosonic (ketodeoxyoctonic) acid (Kdo) and l-glycero-d-manno-Heptoses (l,d-Hep), which are linked to the outer core, characterized by the presence of Glc, GlcN, Gal, and GalNAc (in Aeromonas salmonicida), d,d-Hep (in Aeromonas salmonicida), and l,d-Hep (in Aeromonas hydrophila). The biol. relevance of these differences in the distal part of the outer core among these species has not been fully assessed to date. The inner core is attached to the lipid A, a highly conserved structure that confers endotoxic properties to the LPS when the mol. is released in blood from lysed bacteria, thus inducing a major systemic inflammatory response known as septic or endotoxic shock. In Aeromonas salmonicida subsp. salmonicida the Lipid A components contain three major lipid A mols., differing in acylation patterns corresponding to tetra-, penta- and hexa-acylated lipid A species and comprising of 4'-monophosphorylated β-2-amino-2-deoxy-d-glucopyranose-(1→6)-2-amino-2-deoxy-d-glucopyranose disaccharide. In the present review, we discuss the structure-activity relationships of Aeromonas LPS, focusing on its role in bacterial pathogenesis and its possible applications.
Resumo:
Rockfish species are considered important to the ecology of rocky-reef communities which constitute a key habitat in many coastal marine protected areas (MPAs). These species, which are commercially valuable for artisanal fisheries in the Mediterranean, display particular biological traits that could render them vulnerable to fishing. In this study we monitored the artisanal fisheries of scorpaenids (Scorpaena spp.) in the MPA of Cap de Creus (northwestern Mediterranean) in order to estimate the status of their populations, to link captures with the reproduction of these species, and to evaluate the potential impact that artisanal fishing may have on them. Data from onboard sampling with artisanal fishermen and from fisheries statistics (total landings) were used. Total landings and catch per unit of effort (CPUE) follow a clearly seasonal cycle, with a prominent peak during the summer months coinciding with their spawning season, which may be due to mating behavior prior to fertilization. Although maximum sizes are bigger inside the MPA than in non-protected areas situated close by, a significant percentage of individuals caught inside the MPA are below their size at sexual maturity. Although rockfish seem to be favored by the partial protection of the MPA, the allowed artisanal fisheries are probably impacting the reproduction of these species
