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Widely introduced parasitic control programs rely heavily on the use of synthetic or semi-synthetic antiparasitic compounds. The ineffectiveness of these therapies and growing drug resistance of nematodes leads researchers to search for new alternative methods to combat parasites. One proposal is to use the medicinal properties of herbs that have been used in medicine and veterinary practice for a longer period. The research of activity of plant extracts and their fractions are increasingly important to develop therapies that improve the health of humans and also animals. Anthelmintic properties of plant compounds may be used in an environment where invasive forms of parasites develop. At this stage different compounds can affect the growth and development of parasites, such as inhibiting the molting process. Knowledge of the development of nematodes is still incomplete. On account of the simple structure and transparent body of the nematode, Caenorhabditis elegans is a model species to study many phenomena. Development of the nematode (parasitic and free-living) is strictly programmed. Apoptosis is one of the major mechanisms involved in nematode development. The main apoptotic pathway proteins are CED-3, CED-4 (pro-apoptotic) and CED-9 (anti-apoptotic). Changes in the levels of these proteins may alter the course of organogenesis leading to adverse phenotypic effects. Saponins are compounds commonly occurring in the plant kingdom (both in edible plants and herbs). The mechanism of the action of triterpenoidsaponins per cell is not fully understood. They show numerous properties such as immunomodulatory, antiviral, cytotoxic, or antitumor. Particularly derivatives of oleanolic acid and ursolic acid exhibit a variety of pharmacological properties without toxic side-effects. Due to their characteristics active plant compounds, mainly derivatives of pentacyclictriterpenoids, are a potential source of anticancer, cytotoxic and anthelmintic new generation substances. These may affect the development of the parasite to regulate apoptosis. The discovery of the manner in which saponins are involved in apoptosis can be the first step toward the development a new drug for parasite diseases.
UNC-13 protein participates in regulating neurotransmitter release. In Drosophila melanogaster, proteasomal degradation controls UNC-13 levels at synapses. Function of the amino-terminal region of a 207 kDa form of Caenorhabditis elegans UNC-13 is unknown. Yeast two-hybrid and secondary yeast assays identified an F-box protein that interacts with this amino-terminal region. As F-box proteins bind proteins targeted for proteasomal degradation, this protein may participate in degrading a subset of UNC-13 proteins, suggesting that different forms of UNC-13 are regulated differently. Yeast assays also identified an exonuclease, a predicted splicing factor, and a protein with coiled-coil domains, indicating that UNC-13 may affect RNA function.
Translation initiation factor eIF4E binds the m G7 cap of eukaryotic mRNAs and me­diates recruitment of mRNA to the ribosome during cap-dependent translation initia­tion. This event is the rate-limiting step of translation and a major target for translational control. In the nematode Caenorhabditis elegans, about 70% of genes express mRNAs with an unusual cap structure containing m3 2,2,7 G, which is poorly rec­ognized by mammalian eIF4E. C. elegans expresses five isoforms of eIF4E (IFE-1, IFE-2, etc.). Three of these (IFE-3, IFE-4 and IFE-5) were investigated by means of spectroscopy and structural modelling based on mouse eIF4E bound to m7GDP. Intrinsic fluorescence quenching of Trp residues in the IFEs by iodide ions indicated structural differences between the apo and m7G cap bound proteins. Fluorescence quenching by selected cap analogues showed that only IFE-5 forms specific complexes with both m7G- and m3 2,2,7 G-containing caps (Kas 2 x 106M–1 to 7 x 106M–1) whereas IFE-3 and IFE-4 discriminated strongly in favor of m7G-containing caps. These spectroscopic results quantitatively confirm earlier qualitative data derived from affinity chromatography. The dependence of Kas on pH indicated optimal cap binding of IFE-3, IFE-4 and IFE-5 at pH 7.2, lower by 0.4 pH units than that of eIF4E from human erythrocytes. These results provide insight into the molecular mechanism of recognition of structurally different caps by the highly homologous IFEs.
Nematodes were found to synthesize phosphorylcholine-containing molecules not present in higher organisms, i.e. phosphorylcholine-substituted glycosphingolipids and (glyco)proteins. Investigations on the biosynthesis of these structures provided first biochemical evidence for the presence of the Kennedy and Bremer-Greenberg pathways in the model organism Caenorhabditis elegans.
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