Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 23

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Background. Genetic traceability of seafood as well as population identification using molecular methods provide useful information about the fish origin and are important for protection of overfished populations, as well as for monitoring illegal, unreported, and unregulated (IUU) fisheries. The presently reported study focused on Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816)—a pelagic species with a wide range of distribution—especially important for many tropical countries, such as India, Philippines, and Thailand. This paper is the first part of a larger project: ”Development of a genetic-based system for identification of food products from fisheries and aquaculture introduced to the European Union customs area”. Materials and Methods. Samples consisting of fin fragments of Indian mackerel were obtained from local markets in Thailand (MTH), Vietnam (SVN), Cambodia (SKH), and Madagascar (SMG) within 2012–2013. Two genes were analysed: nuclear rhodopsin gene (RH1) and mitochondrial D-loop (D-loop) region through RFLP analysis simulation and sequencing. Additionally, the samples from Cambodia and Madagascar were analysed with eight microsatellite loci (SSR). The data processing was aided by GenAlEx 6.5 and GeneClass2 software. Results. A comparison of the RH1 gene section revealed a total homology among the studied samples. A comparative analysis of D-loop sequences in the studied groups revealed intrapopulational diversity for MTH-, SKH-, SMG-, and SVN samples, at the level of 1, 1, 0.5, and 0.6 percentage points, respectively. Furthermore, the D-loop sequences identified a characteristic restriction site for SMG population. Based on the allele frequencies, we randomly assigned selected individuals to their original populations. GeneClass2 software correctly assigned only 16 out of 21 individuals to either the Cambodian or the Madagascar population, which jointly constituted 76% of all samples. We demonstrated, using AMOVA and GenAlEx 6.5, that the highest level of variability occurred among individuals within the respective populations, while the lowest interpopulation diversity was between the SMG and SKH populations. Conclusion. Our results may help the relevant authorities in the countries of the European Union to identify Indian mackerel and especially its products and trace them to the respective locality. Our findings may also be used for species-specific conservation measures hopefully undertaken by fisheries authorities of the countries where we took our samples. Results on other fish species, prepared in the frames of the same project, will be presented in other papers that will follow soon.
Eels offered on the Polish market are not only imported mainly from China but also from domestic catches. It is known that Chinese breeders are buying most of their montče eels from Europe, so it is highly probable that “Chinese” eels are Anguilla anguilla, but also Anguilla japonica. There is no data available concerning ratio between these two species on the Polish market. Morphological methods applied to establish this ratio are not reliable enough. Therefore the aim of the presently reported study was to differentiate the eel species using molecular methods. A total of 31 freshwater eels were collected from a local importer (21 samples) and from Lake Miedwie near Szczecin (10 samples). At the beginning of the eel identification process morphometric measurements have been performed. In attempting to distinguish A. japonica and A. anguilla PCR products of partial 16S rRNA gene, a PCR-RFLP procedure was applied, which is mainly base on nucleotide differences between species sequences. In this method the ApaI restriction enzyme was used to conduct the digestion of the PCR product. Primers named Ang211F and Ang211R were designed for the amplification the 211 bp of 16S rRNA sequence of both eel species. Electrophoretic pattern of PCR products from A. japonica and A. anguilla did not indicate any difference in length. As a result, ApaI produced fragments of 135 and 76 bp only for A. japonica, while the A. anguilla sequence was not digested with its length of 211 bp. Products of ApaI digestion of partial 16S rRNA gene of A. japonica and A. anguilla are suitable genetic markers to distinguish both eel species.
A new monogenean species Neoheterobothrium hippoglossini sp. n. from the gill cavity of Hippoglossina stomata Steindachner, 1876 is described and illustrated. The new species differs from its seven congeners in a number of morphological features and in having a different host. The validity of the genus Neoheterobothrium is discussed. Neoheterobothrium mcdonaldi Payne, 1987 is relegated from the genus and from the subfamily Choricotylinae and placed in one of the remaining subfamilies of the family Diclidophoridae.
The aim of this research was to explain the etiology of pathological changes that have occurred on the body of goldfish (Carassius auratus). All samples were obtained from a fish farm that utilizes cooling water from the power station Dolna Odra. Since 2008 a few such cases have been sporadically observed there. An excised part of the tissue was analyzed based on histological assays and also by means of a transmission electron microscope (TEM). Histological staining showed that the tumor originated from the mesenchymal tissue with many blood vessels in its structure. The conducted research showed neither pathological changes caused by oncogenic viruses nor viral particles in the tumor tissue. Nevertheless, the most probable reason for these kind of changes is a combination of environmental factors and In Poland specific breeding conditions (warmed waters).
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.