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51.
52.
Jayanta Das Arunoday Bhan Subhrangsu S. Mandal Carl J. Lovely 《Bioorganic & medicinal chemistry letters》2013,23(22):6183-6187
Concise syntheses of two Leucetta-derived naphthimidazole alkaloids, kealiiquinone and 2-deoxy-2-aminokealiiquinone, are described based on a biosynthetic-guided hypothesis. Advanced intermediates containing the full naphthimidazole framework are constructed through Friedel–Crafts chemistry followed by oxidation of the electron rich C-ring with hydrogen peroxide. The cytotoxicity of these alkaloids in a breast cancer cell line along with several closely related marine-derived natural products kealiinines A–C and analogs are reported. 相似文献
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54.
M Onderci K Sahin N Sahin MF Gursu D Doerge FH Sarkar 《Archives of animal nutrition》2013,67(6):463-471
Genistein, a phytoestrogen found in soybeans, is a powerful antioxidant. We evaluated the effects of genistein supplementation on performance, carcass characteristics, levels of malondialdehyde (MDA), homocysteine, vitamins C, E, A in Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature of 34°C. Two hundred and forty Japanese quails (10 d old) were randomly assigned to eight treatment groups consisting of 10 replicates of three birds. The birds were kept in an environmental controlled room either for 24 h/d at 22°C with (thermoneutral, TN groups) or for 16 h/d at 22°C and for 8 h/d (09.00 am to 05.00 pm) at 34°C (heat stress, HS groups). Birds were fed either a basal (control) diet (TN and HS) or the basal diet supplemented with 200, 400 or 800 mg of genistein per kg of diet. Heat exposure decreased birds' performance when basal diet was fed. Increase in feed intake and body weight, and improvement of feed efficiency and carcass traits were found in genistein-supplemented quails reared under heat stress conditions. Growth rate and feed efficiency improved in quails reared under thermo-neutral conditions as well. Concentration of serum vitamins C, E, and A increased in supplemented birds reared at high temperature, while non-significant changes occurred in TN groups. With genistein supplementation homocysteine levels in serum and MDA levels in serum and liver decreased in all birds of both TN and HS groups. Effects of genistein were relatively greater in heat-stressed quails than in quails kept under thermo-neutral conditions. Results of the present study suggest that supplementation with genistein can be considered to be protective by reducing the negative effects of oxidative stress induced by heat stress in quail. 相似文献
55.
The phytopathogenic fungus Ustilago maydis undergoes a dimorphic transition in response to mating pheromone, host, and environmental cues. On a solid medium deficient in ammonium (SLAD [0.17% yeast nitrogen base without ammonium sulfate or amino acids, 2% dextrose, 50 μM ammonium sulfate]), U. maydis produces a filamentous colony morphology, while in liquid SLAD, the cells do not form filaments. The p21-activated protein kinases (PAKs) play a substantial role in regulating the dimorphic transition in fungi. The PAK-like Ste20 homologue Smu1 is required for a normal response to pheromone, via upregulation of pheromone expression, and virulence, and its disruption affects both processes. Our experiments suggest that Smu1 also regulates cell length and the filamentous response on solid SLAD medium. Yeast two-hybrid analysis suggested an Hsl7 homologue as a potential interacting partner of Smu1, and a unique open reading frame for such an arginine methyltransferase was detected in the U. maydis genome sequence. Hsl7 regulates cell length and the filamentous response to solid SLAD in a fashion opposite to that of Smu1, but neither overexpression nor disruption of hsl7 attenuates virulence. Simultaneous disruption of hsl7 and overexpression of smu1 lead to a hyperfilamentous response on solid SLAD. Moreover, only this double mutant strain forms filaments in liquid SLAD. The double mutant strain was also significantly reduced in virulence. A similar filamentous response in both solid and liquid SLAD was observed in strains lacking another PAK-like protein kinase involved in cytokinesis and polar growth, Cla4. Our data suggest that Hsl7 may regulate cell cycle progression, while both Smu1 and Cla4 appear to be involved in the filamentous response in U. maydis. 相似文献
56.
Phillip Q Spinks Robert C Thomson Geoff A Lovely H Bradley Shaffer 《BMC evolutionary biology》2009,9(1):56
Background
Phylogenies often contain both well-supported and poorly supported nodes. Determining how much additional data might be required to eventually recover most or all nodes with high support is an important pragmatic goal, and simulations have been used to examine this question. Most simulations have been based on few empirical loci, and suggest that well supported phylogenies can be determined with a very modest amount of data. Here we report the results of an empirical phylogenetic analysis of all 10 genera and 25 of 48 species of the new world pond turtles (family Emydidae) based on one mitochondrial (1070 base pairs) and seven nuclear loci (5961 base pairs), and a more biologically realistic simulation analysis incorporating variation among gene trees, aimed at determining how much more data might be necessary to recover weakly-supported nodes with strong support. 相似文献57.
Morgana Camacho Thaíla Pessanha Daniela Leles Juliana MF Dutra Rosangela Silva Sheila Mendon?a de Souza Adauto Araujo 《Memórias do Instituto Oswaldo Cruz》2013,108(2):155-159
Parasite findings in sambaquis (shell mounds) are scarce. Although the 121 shell mound samples were previously analysed in our laboratory, we only recently obtained the first positive results. In the sambaqui of Guapi, Rio de Janeiro, Brazil, paleoparasitological analysis was performed on sediment samples collected from various archaeological layers, including the superficial layer as a control. Eggs of Acanthocephala, Ascaridoidea and Heterakoidea were found in the archaeological layers. We applied various techniques and concluded that Lutz''s spontaneous sedimentation technique is effective for concentrating parasite eggs in sambaqui soil for microscopic analysis. 相似文献
58.
Sefika C Mizrak Bart M Gadella Hatice Erdost Aytekin Ozer Ana MM van Pelt Federica MF van Dissel-Emiliani 《Reproductive biology and endocrinology : RB&E》2008,6(1):1-9
Background
The placenta is an important site for iron metabolism in humans. It transfers iron from the mother to the fetus. One of the major iron transport proteins is transferrin, which is a blood plasma protein crucial for iron uptake. Its localization and expression may be one of the markers to distinguish placental dysfunction.Methods
In the experimental study we used antibody preparation, mass spectrometric analysis, biochemical and immunocytochemical methods for characterization of transferrin expression on the human choriocarcinoma cell line JAR (JAR cells), placental lysates, and cryostat sections. Newly designed monoclonal antibody TRO-tf-01 to human transferrin was applied on human placentae from normal (n = 3) and abnormal (n = 9) pregnancies.Results
Variations of transferrin expression were detected in villous syncytiotrophoblast, which is in direct contact with maternal blood. In placentae from normal pregnancies, the expression of transferrin in the syncytium was significantly lower (p < 0.001) when compared to placentae from abnormal ones (gestational diabetes, pregnancy induced hypertension, drug abuse).Conclusion
These observations suggest that in the case of abnormal pregnancies, the fetus may require higher levels of transferrin in order to prevent iron depletion due to the stress from the placental dysfunction. 相似文献59.
Binding to serine 65‐phosphorylated ubiquitin primes Parkin for optimal PINK1‐dependent phosphorylation and activation 下载免费PDF全文
Agne Kazlauskaite R Julio Martínez‐Torres Scott Wilkie Atul Kumar Julien Peltier Alba Gonzalez Clare Johnson Jinwei Zhang Anthony G Hope Mark Peggie Matthias Trost Daan MF van Aalten Dario R Alessi Alan R Prescott Axel Knebel Helen Walden Miratul MK Muqit 《EMBO reports》2015,16(8):939-954
Mutations in the mitochondrial protein kinase PINK1 are associated with autosomal recessive Parkinson disease (PD). We and other groups have reported that PINK1 activates Parkin E3 ligase activity both directly via phosphorylation of Parkin serine 65 (Ser65)—which lies within its ubiquitin‐like domain (Ubl)—and indirectly through phosphorylation of ubiquitin at Ser65. How Ser65‐phosphorylated ubiquitin (ubiquitinPhospho‐Ser65) contributes to Parkin activation is currently unknown. Here, we demonstrate that ubiquitinPhospho‐Ser65 binding to Parkin dramatically increases the rate and stoichiometry of Parkin phosphorylation at Ser65 by PINK1 in vitro. Analysis of the Parkin structure, corroborated by site‐directed mutagenesis, shows that the conserved His302 and Lys151 residues play a critical role in binding of ubiquitinPhospho‐Ser65, thereby promoting Parkin Ser65 phosphorylation and activation of its E3 ligase activity in vitro. Mutation of His302 markedly inhibits Parkin Ser65 phosphorylation at the mitochondria, which is associated with a marked reduction in its E3 ligase activity following mitochondrial depolarisation. We show that the binding of ubiquitinPhospho‐Ser65 to Parkin disrupts the interaction between the Ubl domain and C‐terminal region, thereby increasing the accessibility of Parkin Ser65. Finally, purified Parkin maximally phosphorylated at Ser65 in vitro cannot be further activated by the addition of ubiquitinPhospho‐Ser65. Our results thus suggest that a major role of ubiquitinPhospho‐Ser65 is to promote PINK1‐mediated phosphorylation of Parkin at Ser65, leading to maximal activation of Parkin E3 ligase activity. His302 and Lys151 are likely to line a phospho‐Ser65‐binding pocket on the surface of Parkin that is critical for the ubiquitinPhospho‐Ser65 interaction. This study provides new mechanistic insights into Parkin activation by ubiquitinPhospho‐Ser65, which could aid in the development of Parkin activators that mimic the effect of ubiquitinPhospho‐Ser65. 相似文献