738 resultados para catfish venoms


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Secretory phospholipase A2 (sPLA2) is known as a major component of snake venoms and displays higher-order catalytic hydrolysis functions as well as a wide range of pathological effects. Atheris is not a notoriously dangerous genus of snakes although there are some reports of fatal cases after envenomation due to the effects of coagulation disturbances and hemorrhaging. Molecular characterization of Atheris venom enzymes is incomplete and there are only a few reports in the literature. Here, we report, for the first time, the cloning and characterization of three novel cDNAs encoding phospholipase A2 precursors (one each) from the venoms of the Western bush viper (Atheris chlorechis), the Great Lakes bush viper (Atheris nitschei) and the Variable bush viper (Atheris squamigera), using a “shotgun cloning” strategy. Open-reading frames of respective cloned cDNAs contained putative 16 residue signal peptides and mature proteins composed of 121 to 123 amino acid residues. Alignment of mature protein sequences revealed high degrees of structural conservation and identity with Group II venom PLA2 proteins from other taxa within the Viperidae. Reverse-phase High Performance Liquid Chromatography (HPLC) profiles of these three snake venoms were obtained separately and chromatographic fractions were assessed for phospholipase activity using an egg yolk suspension assay. The molecular masses of mature proteins were all identified as approximately 14 kDa. Mass spectrometric analyses of the fractionated oligopeptides arising from tryptic digestion of intact venom proteins, was performed for further structural characterization.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Amphibian defensive skin secretions and reptile venoms are rich sources of bioactive peptides with potential pharmacological/pharmaceutical applications. As amphibian and reptile populations are in rapid global decline, our research
group has been developing analytical methods that permit generation of robust molecular data from non-invasive skin secretion samples and venom samples. While previously we have demonstrated that parallel proteome and venom gland
transcriptome analyses can be performed on such samples, here we report the presence of DNA that facilitates the more widely-used applications of gene sequencing, such as molecular phylogenetics, in a non-invasive manner that circumvents specimen sacrifice. From this “surrogate” tissue, we acquired partial 12S and 16S rRNA gene sequences that are presented for illustration purposes. Thus from a single sample of amphibian skin secretion and reptile venom, robust and complementary proteome, transcriptome and genome data can be generated for applications in diverse scientific disciplines.

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Wapsipinicon River, affectionately known as the “Wapsi,” flows nearly 300 miles through northeastern Iowa to the Mississippi. Strung throughout its drainage basin is a series of dams that are highly valued by their communities as places of recreation and scenic beauty. The Wapsipinicon has long had a reputation as a fishing stream, known for catfish, northern pike, carp, sunfish, walleye, and smallmouth bass. It is not uncommon to find anglers of all ages gathered at one of the Wapsipinicon’s dams to enjoy a day of fishing and possibly take home a prize catch. As time passes, however, a dam may outlive its original function, impede fish passage, and pose a safety hazard. But the idea of demolishing an outdated dam often rallies the community in an attempt to preserve the landmark.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Os ambientes aquáticos continentais da metade sul do RS são caracterizados por uma ampla planície costeira, onde destaca-se a Lagoa Mirim, com uma área total binacional (Brasil e Uruguai) de 3.750 Km². Nesta região, a pesca é uma importante atividade sócio-econômica, porém, a economia da região baseia-se no cultivo do arroz e na criação de gado. A proposta deste trabalho foi realizar um diagnóstico preliminar desta atividade na L. Mirim. A metodologia foi baseada na aplicação de formulários aos pescadores artesanais (perfil sócio-econômico e características da pesca) e na identificação das espécies que compunham a captura proveniente do desembarque pesqueiro no entorno da L. Mirim (Jaguarão, Santa Isabel e Santa Vitória do PalmarPorto e Curral Alto). Os dados de captura total de pescado foram provenientes de fontes independentes e complementares. O estudo sugere um perfil do pescador artesanal composto por 71% de indivíduos de sexo masculino, entre 20 e 65 anos de idade que costumam ficar de uma semana a quinze dias embarcados. A maioria (71%) dos pescadores artesanais entrevistados possui somente ensino fundamental e seus familiares geralmente estão envolvidos na atividade pesqueira. Foram identificados 28 locais de pesca e as principais espécies capturadas pela pesca artesanal foram: traíra Hoplias malabaricus, jundiá Rhandia aff. quelen, pintado Pimelodus maculatus, peixerei Odontesthes spp, viola-cascuda Loricariichthys anus e tambico Oligosarcus spp. A traíra foi a espécie mais representativa em peso (> 40%). Estas espécies apresentaram flutuações na composição das capturas ao longo do ano; os menores valores foram registrados entre julho e setembro (meses frios), exceto para o peixe-rei. A análise dos dados também aponta uma variação interanual dos valores totais de pescado e alguns fatores que podem estar associados à diminuição da captura são os prolongados períodos de seca na região, o uso da água na orizicultura e a falta de fiscalização da atividade pesqueira. Estudos baseados em estimativas de pescarias e conhecimento sobre a biologia das espécies capturadas podem fornecer subsídios para o correto manejo dos recursos pesqueiros, para tanto, são necessárias pesquisas que investiguem aspectos do uso sustentado das espécies de importância econômica na região e os possíveis efeitos da atividade pesqueira sobre a estrutura e a biodiversidade do ecossistema. Assim, para garantir a sustentabilidade da Lagoa Mirim, faz-se necessário envolver os pescadores artesanais e suas estratégias de pesca, em função de seus conhecimentos ecológicos, nas pesquisas que integram a elaboração das políticas públicas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fisheries support livelihoods but are threatened by climate variability and change which intensified since the 1970s. This study used quantitative and qualitative methods to determine the extent to which fishers around Lake Wamala in Uganda were copying with perceived changes in climate variables and the impacts on their livelihoods, to generate knowledge to enable the fishers increase resilience and sustain their livelihoods. Fishers were aware of changes in climate manifested by unpredictable seasons, floods and droughts. Fishing was the main livelihood activity. The African catfish had replaced Nile tilapia as the dominant fish species. There was damage and loss of gear, boats, landing sites and lives, and changes in fish catches and sizes, income and fish consumption during the perceived floods and droughts. The fishers adapted to the changes through increasing time on fishing grounds and changing target species and fishing gears but innovative ones diversified to high value crops and livestock which increased their income beyond what was earned from fishing thus acting as an incentive for some of them to quit fishing. Diversification to non-fishery activities as a form of adaptation was enhanced by membership to social groups, weekly fishing days, fishing experience and age of fishers but its benefits were not equally shared among men and women. Mitigation measures included planting trees, mulching gardens and protecting wetlands. Adaptation and mitigation measures were constrained by limited credit, awareness and land. The required interventions included improving access to credit, irrigation facilities and appropriate planting materials and raising awareness. The study showed that the fishers were aware of changes in climatic variables and the impacts on their livelihoods. There were also adaptation and mitigation measures practiced by the fishers which if promoted and their constraints addressed, could increase resilience of fishers to climatic change and sustain their livelihoods.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The fish meat has a particular chemical composition which gives its high nutritional value. However, this food is identified for being highly perishable and this aspect is often named as a barrier to fish consumption. The southwestern Paraná region, parallel to the country's reality, it is characterized by low fish consumption; and one of the strategies aimed at increasing the consumption of this important protein source is encouraging the production of other species besides tilapia. Within this context, it is necessary to know about the meat characteristics. In this sense, the objective of this study was to evaluate the technological potential of pacu, grass carp and catfish species. To do so, at first, it was discussed the chemical and biometric assessment under two distinct descriptive statistical methods, of the three species; and it was also evaluated the discriminating capacity of the study. In a second moment, an evaluation of effects done by two different processes of washing (acid and alkaline) regarding the removal of nitrogen compounds, pigments and the emulsifying ability of the proteins contained in the protein base obtained. Finally, in the third phase, it was aimed to realize the methodology optimization in GC-MS for the analysis geosmin and MIB (2-metilisoborneol) compounds that are responsible for taste/smell of soil and mold in freshwater fish. The results showed a high protein and low lipid content for the three species. The comparison between means and medians revealed symmetry only for protein values and biometric measurements. Lipids, when evaluated only by the means, overestimate the levels for all species. Correlations between body measurements and fillet yield had low correlation, regardless of the species analyzed, and the best prediction equation relates the total weight and fillet weight. The biometric variables were the best discriminating among the species. The evaluation of the washings, it was found that the acidic and basic processes were equally (p ≥ 0.05) efficient (p ≤ 0.05) for the removal of nitrogen compounds on the fish pulps. Regarding the extraction of pigments, a removal efficiency was recorded only for the pacu species, the data were assessed by the parameters L *, a *, b *. When evaluated by the total color difference (ΔE) before and after washing for both processes (acid/alkaline) the ΔE proved feasible perceived by naked eye for all species. The catfish was characterized as the fish that presents the clearest meat with the basic washing considered the most effective in removing pigments for this species. Protein bases obtained by alkaline washes have higher emulsifying capacity (p ≤ 0.05) when compared to unwashed and washed in acid process pulps. The methodology applied for the quantification of MIB and geosmin, allowed to establish that the method of extraction and purification of analytes had low recovery and future studies should be developed for identification and quantification of MIB and geosmin on fish samples.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The parasites fauna of 491 specimens of Sander lucioperca, Linnaeus 1758 (246 specimens) and catfish, Silurus glanis, Linnaeus 1758 (245 specimens) in different size from Aras Reservoir situated in North —west of the Iran was investigated. During 2006-2007 Totally 16 parasite species were recorded. The most various parasites was found in catfish (10 species) while the lowest number was recorded in Sander lucioperca (6 species). Among them, however three genera of protozoa (Trichodina, Vorticella, Ichthyophthirius), two genera of Monogenea (Gyrodactylus, Silurodiscoides), Digenea, Cestoda, Nematoda, Acanthocephala and Annelida one species each (Diplostomum, Protocephalus, Eustrongylides, Neoechinorhynchus, Pisicola) and two crustacean genera (Argulus and Lernea) recorded and we can come to conclusion in comparison with the earlier data the actual parasite fauna of two hosts has been greatly improved. According to the present study the prevalence, mean abundance and mean intensity of parasites species of both hosts were highly influenced by seasons of the year. Some species found, however show a tendency to be more abundant ides Trichodina sp., Ichthyophthirius multifiliis, Silurodiscoides vistolensis, Protocephalus osculatus respectively. Most parasites species live in gills and skin, where is highly sensitive to some pathogens parasites species (Trichodina, Vorticella, Ichthyophthirius, Pisicola geometra, Argulus foliaceus; Lernea) and While some are specialist (Silurodiscoides vistolensis and Silurodiscoides siluri) other more or less generalist (ichthyophthirius).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Ornamental fish are more expensive in comparison with the other fish. It especially highlights in non-breeding fish (in imported one for importation costs). But of course, with entering the new and unhealthy fishes to aquarium or ponds, they may transmit a pathogen to others (interfere with Iran ornamental fish parasitic fauna). In this study (Dec. 2008- Sep. 2009), 400 fish gill arch from 4 species of ornamental fish (within focus on imported fish); namely, i.e. Goldfish (Carassius auratus), platyfish (Xiphophorus maculatus), Dwarf gourami (Colisa lalia) and Catfish (Hypostomus plecostomus) were inspected for gill ectoparasites and then pathologic effects (but in high- affected gill). In this study, seven protozoan and ten metazoan species, indeed seventeen parasite species were identified. Protozan parasites consist of: Trichodina spp. and Ichthyophthirius multifiliis were found in four fish species; Ichthyobodo necatrix (Costia necator/C. necatrix) and Cryptobia branchialis, were respectively found in Dwarf gourami and goldfish. The highest prevalence belongs to Ichthyophthirius (47%) in platyfish. Metazoan parasites consist of: Ancyrocephalus sp. (Dwarf gourami), Ancylodiscoides spp. (catfish and platyfish), Dactylogyrus vastator, D. baueri, D. formosus (only in goldfish) and Gyrodactylus spp. (in four fish species). The highest prevalence was related to Dactylogyrus vastator(82%) in goldfish. Histological effects in case with high prevalence of parasite were also observed, e.g., hypertrophy, Lamellar hyperplasia and fusion. In high-parasitized gill, there is dysfunction of gill.