Search results for "fishes"
showing 10 items of 319 documents
Effects of primary- and secondary-treated bleached kraft mill effluents on the immune system and physiological parameters of roach.
2000
The present study was designed to examine, whether, effluents from a modern pulp and paper mill using elemental chlorine-free/total chlorine-free (ECF/TCF) bleaching, exert effects on the immune system of fish and, in addition, to relate these findings to physiological parameters known to be affected by bleached kraft-mill effluents (BKME). Roach (Rutilus rutilus) were exposed in laboratory conditions to primary- or secondary-treated effluent from a pulp and paper mill. In order to study their capability to respond to foreign antigens they were immunised with bovine gamma-globulin (BGG) prior to exposure. The number of anti-BGG antibody-secreting cells (ASC) and the number of immunoglobulin…
Phage-driven loss of virulence in a fish pathogenic bacterium
2012
Parasites provide a selective pressure during the evolution of their hosts, and mediate a range of effects on ecological communities. Due to their short generation time, host-parasite interactions may also drive the virulence of opportunistic bacteria. This is especially relevant in systems where high densities of hosts and parasites on different trophic levels (e.g. vertebrate hosts, their bacterial pathogens, and virus parasitizing bacteria) co-exist. In farmed salmonid fingerlings, Flavobacterium columnare is an emerging pathogen, and phage that infect F. columnare have been isolated. However, the impact of these phage on their host bacterium is not well understood. To study this, four s…
Improving marine protected area governance through collaboration and co-production.
2020
Marine protected areas (MPAs) socio-ecological effectiveness depends on a number of management and governance elements, among which stakeholder engagement and community support play key roles. Collaborative conservation initiatives that engage stakeholders in action research and knowledge co-production processes can enhance management and governance of MPAs. To design effective strategies aimed at reconciling biodiversity conservation and management of sustainable human uses, it is key to assess how local communities respond to such initiatives and identify the set of contextual factors, institutional, local and individual, potentially affecting these responses. This paper presents the appr…
Metabolism of chlorobenzene and hexachlorobenzene by the zebra fish, Brachydanio rerio.
1989
It is now becoming evident that in many cases metabolites have a greater toxic potential than the parent xenobiotic exposed. For this reason, the knowledge of biotransformation pathways of xenobiotics plays a substantial role in environmental monitoring programs. The zebra fish (Brachydanio rerio, Hamilton-Buchanan) has received increased attention as a model species for freshwater fish in environmental surveillance programs to evaluate potential health and impacts of anthropogenic chemicals. The metabolism of phenol and various substituted phenols in zebra fish has recently been studied. The purpose of the present study was to examine the metabolism of chlorobenzene and hexachlorobenzene (…
Speciation of methylmercury in market seafood by thermal degradation, amalgamation and atomic absorption spectroscopy
2014
Sample thermal decomposition followed by mercury amalgamation and atomic absorption has been employed for the determination of methylmercury (MeHg) in fish. The method involves HBr leaching of MeHg, extraction into toluene, and back-extraction into an aqueous l-cysteine solution. Preliminary studies were focused on the extraction efficiency, losses, contaminations, and species interconversion prevention. The limit of detection was 0.018µgg(-1) (dry weight). The intraday precision for three replicate analysis at a concentration of 4.2µgg(-1) (dry weight) was 3.5 percent, similar to the interday precision according to analysis of variance (ANOVA). The accuracy was guaranteed by the use of for…
Comparative study of the arterial and lacunary systems of the ventricular myocardium of elasmobranch and teleost fishes.
1983
The typical fish heart has a spongy trabeculated ventricular myocardium (spongiosa) supplied by the venous blood of the intertrabecular spaces (lacunae); hence it is called a "venous heart." However, in some fishes a more complex ventricular muscle is found (mixed type), in which the spongiosa is covered by an outer layer of densely arranged myocardial bundles (compacta). The compacta receives oxygenated blood from the coronary vessels. The objective of this study was to investigate relations between myoarchitecture and blood supply with an emphasis on the hitherto unexplored, putative vascular connections between the arterial and the lacunary circuits. Using histological methods combined w…
Acanthocephalans from Marine Fishes from Patagonia, Argentina
2019
In this study, 542 individual fish from 20 species from the Patagonian continental shelf of Argentina were examined for acanthocephalans. A total of 1,547 acanthocephalans belonging to 5 species were collected from 18 species of fish. Adult forms were represented by 2 species: Aspersentis johni (Baylis, 1929) (Heteracanthocephalidae) from longtail southern cod, Patagonotothen ramsayi (Regan) (new host record), and Breizacanthus aznari Herna´ndez-Orts, Alama-Bermejo, Crespo, Garcı´a, Raga and Montero, 2012 (Arhythmacanthidae) from raneya, Raneya brasiliensis (Kaup). Immature worms of B. aznari were also collected from the intestine of pink cusk-eel, Genypterus blacodes (Forster) (new host re…
Evolution of tissue-specific keratins as deduced from novel cDNA sequences of the lungfish Protopterus aethiopicus.
2005
Lungfishes are possibly the closest extant relatives of the land vertebrates (tetrapods). We report here the cDNA and predicted amino acid sequences of 13 different keratins (ten type I and three type II) of the lungfish Protopterus aethiopicus. These keratins include the orthologs of human K8 and K18. The lungfish keratins were also identified in tissue extracts using two-dimensional polyacrylamide gel electrophoresis, keratin blot binding assays and immunoblotting. The identified keratin spots were analyzed by peptide mass fingerprinting which assigned seven sequences (inclusively Protopterus K8 and K18) to their respective protein spot. The peptide mass fingerprints also revealed the fac…
Impacts of piscicide-induced fish removal on resource use and trophic diversity of lake invertebrates
2022
Chemical eradication of non-native species has become a widely used method to mitigate the potential negative im- pacts of altered competitive or predatory dynamics on biodiversity and natural ecosystem processes. However, the re- sponses of non-target species can vary from rapid full recovery to delayed or absent recolonization, and little is known about the potential shifts in resource use and trophic diversity of native species following chemical treatments. We used a before-after-control-impact approach to study the effects of rotenone piscicide treatment on abundance and tro- phic niche of benthic invertebrates in three untreated and three treated lakes in central Norway, the latter gr…
Toxic and enzymatic activities of Vibrio vulnificus biotype 2 with respect to host specificity
1996
In this work, the enzymatic activities of selected strains of biotypes 1 and 2 of Vabrio vulnificus were analyzed by using conventional methods and the API ZYM system. The toxic activities of extracellular products (ECPs) were further evaluated by in vitro and in vivo experiments. The ECPs of both biotypes (i) showed high-level hydrolytic activities, (ii) displayed cytotoxicity for fish cell lines, and (iii) were lethal for eels. Exotoxins seem to be proteinaceous since heat treatment of ECP samples destroyed their toxicity. Only biotype 2 strains were virulent for cels, suggesting that host specificity must be related to differences in cell surface properties. Infectivity trials with other…