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Considering high nutritive value and sensory qualities, the products manufactured of marine invertebrates are a desirable component of human diet. These products enjoy an increasing demand in Poland. However, considerable accumulation of chlorine- organic pollutants in the tissues of marine animals may pose a threat for consumers. The study included determination of the content of PCB congeners (28, 52, 101, 118, 138, 153, and 180 according to IUPAC) in tinned and pickled seafood products purchased in Szczecin’s fishshops. In all examined products the analysed congeners were found, only in “Octopus in vegetable oil” PCB 138 was not detected. The highest content, 13.8 μg-kg_l m.m. (99.237 μg-kg’1 lipids), was recorded for PCB congener 153 in “Squid in American sauce”. The lowest residue levels were found for PCB 101 (0.002 to 0.07 μg-kg'1 m.m.). The highest percentage (from among analysed congeners) in majority of examined products was found for PCB 153 (to 95% in “Octopus in vegetable oil”) and PCB 180 (to 58% in “Pickled mussels”). The lowest percentage was stated for PCB congeners 101 (to 2.2% in “Shrimps natural”) and 52 (to 9.9% in “Greenland shrimps in brine”).
Nucleotide sequence divergence in a novel major mitochondrial DNA intergenic spacer (IGS) of Pacific oyster Crassostrea gigas was analyzed for 29 cultured individuals within the Goseong population (Korea). A total of 7 variable sites were detected within the IGS, and the relative frequency of nucleotide alteration was determined to be 1.16%. All alterations were due to a single nucleotide substitution, and 5 transitions and 2 transversions were observed. Among 29 specimens, only 8 haplotypes could be identified, and 6 of the haplotypes were unique to particular specimens. Pairwise genetic diversity of all 8 haplotypes was calculated to be 0.412 ± 0.134 from multiple sequence substitutions based on the two-parameter model. The phylogenetic tree obtained for these haplotypes according to the neighbor-joining method illustrated a single cluster of linkages, which comprised 5 haplotypes associated with 23 specimens, while the other 3 haplotypes associated with 6 specimens were scattered. The results indicate that the IGS is higher polymorphic and thus more suitable as a genetic marker for population structure analysis of Pacific oyster than the mtDNA coding regions, such as cytochrome c oxidase I and 16S ribosomal RNA genes.
Nucleotide sequence polymorphism in a 641-bp novel major noncoding region of mitochondrial DNA (mtDNA-NC) of the Pacific oyster Crassostrea gigas was analysed for 29 cultured individuals within the Goseong population. A total of 30 variable sites were detected, and the relative frequency of nucleotide alteration was determined to be 4.68. Alterations were mostly single nucleotide substitutions. Transition, transversion, both transition and transversion, and both transversion and nucleotide deletion were observed at 18, 9,2 and 1 sites, respectively. Among 29 specimens, 22 haplotypes were identified, and pairwise genetic diversity of haplotypes was calculated to be 0.988 from multiple sequence substitutions using the two-parameter model. A phylogenetic tree, obtained for haplotypes by the neighbor-joining method, showed a single cluster of linkages. The cluster comprised 11 haplotypes associating with 14 specimens, while the other 11 haplotypes associating with 15 specimens were scattered. This mtDNA-NC presenting a high nucleotide sequence polymorphism is a potential mtDNA control region. It therefore can serve as a genetic marker for intraspecies phylogenetic analysis of the Pacific oyster and is more useful than the less polymorphic mtDNA coding genes.
The marine Pliocene at the locality of Nefiach (Roussillon Basin, SE France) includes several shell beds constituted by oysters and scallops that bear a diverse and abundant bioerosion trace fossil assemblage. The most abundant trace fossils are Gnathichnus pentax and Radulichnus inopinatus, produced by the grazing activity of echinoids and polyplacophorans upon algae and other microorganisms coating shell surfaces. Other bioerosion traces include polychaete dwellings (Caulostrepsis taeniola and Maeandropolydora sulcans), sponge boring systems (Entobia isp.), and rare bryozoan borings (Pinaceocladichnus isp.), predation structures (Oichnus simplex and repaired durophagous scars), and foraminiferal fixation pits (Centrichnus cf. eccentricus). The trace fossil assemblage records short−term bioerosion in shellgrounds in a moderate energy setting as evinced by the dominance of epigenic or shallow endogenic structures produced in most cases by “instantaneous” behaviors. The assemblage can be assigned to the Gnathichnus ichnofacies, and it contrasts with that found in Pliocene rocky shores in the same geographic area, which are examples of the Entobia ichnofacies. The Gnathichnusichnofacies is validated as an archetypal one and its recurrency demonstrated since the Jurassic. Entobia and Gnathichnus ichnofacies have to be used in the Mesozoic and Cenozoic as substitutes of the previously existing Trypanites ichnofacies, which is still valid in the Palaeozoic.
A simple and reliable method was developed for extracting genomic DNA from preserved mantle tissues of Pacific oyster Crassostrea gigas for reproducible PCR amplification. The method was based on destruction of the tissue using Proteinase K, Chelex 100 resin, detergents, and urea, followed by preferential capturing of genomic DNA with silica particles. Approximately 5 mg of mantle tissue provided a sufficient quality and quantity of DNA for several hundreds of PCR reactions amplifying the hypervariable mitochondrial DNA intergenic spacer, which is a useful genetic marker for population structure analysis of Pacific oyster. The method can be applied for DNA preparation from not only fresh and frozen but also ethanol-preserved mantle tissues, so this rapid and economical method can serve for investigating a large number of bivalve specimens collected in the field and next transported in ethanol at ambient temperature.
The qualitative and quantitative evaluation of the content of volatile aroma compounds in the fruit bodies of two species of edible mushrooms: oyster (Pleurotus ostreatus) and nameko (Pholiota nameko) was performed by gas chromatography coupled with mass spectrophotometry. Both examined species of fungi differed from each other in the amounts of the main volatile substances. The most important components determining the aroma of these mushrooms were octen-1,3-ol and octanal. It was also shown that the retention of these substances was effected by the method of sample preparation for the analyses and the method of liophilization. The sublimatic drying enabled the retention of 50% of aroma compounds in oyster fruit bodies and 39.2% in nameko fruitbodies. Freezing of fruit bodies after harvesting enabled the retention of 63.5% of aroma compounds in oyster fruit bodies and 75% in nameko fruitbodies.
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