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1.
Aneta Ivanova Margarita Velcheva Plamen Denchev Atanas Atanassov Henri A. Van Onckelen 《Physiologia plantarum》1994,92(1):85-89
Endogenous indole-3-acetic acid, abscisic acid and cytokinins (zeatin, zeatin riboside, N-isopentenyladenine and N-isopentenyladenosine) were evaluated in initial explants (leaves) of in vitro propagated plants of alfalfa ( Medicago falcata L.) lines varying in embryogenic capacity and during the somatic embryogenesis process. Fast embryo-genic induction was correlated with high IAA and low ABA levels in the initial explants. No significant differences were observed in the cytokinin contents. Our results suggest that a certain hormone balance is necessary to allow the expression of the embryogenic potential. The consistent stages of the direct somatic embryogenesis are also characterized by changes in hormonal levels. 相似文献
2.
Vasil Pirgozliev Stephen C. Mansbridge Izzy M. Whiting Stephen P. Rose Kristina Kljak Amy E. Johnson Falko Drijfhout Sylwia Orczewska-Dudek Atanas G. Atanasov Teodora Mihova 《The Annals of applied biology》2023,183(1):7-14
The aim of this study was to assess the effects of graded levels (0, 3, 6, 9 and 12 g/kg) of dry Sea buckthorn (SB) berries on growth performance, gastrointestinal tract (GIT) development, jejunal histomorphology, bird antioxidant status and caecal short-chain fatty acid concentration when fed to female Ross 308 broiler chickens. In addition, expression of cytokine biomarker genes in the jejunum was evaluated. The five experimental diets were fed from 7 to 21 days age to 8 pens (two birds in each) following randomisation. Feeding SB did not influence bird growth performance (p > .05). There was a linear decrease in butyric, acetic and valeric acid concentrations in caecal digesta (p < .05) and a decrease (p < .05) in crypt depth. The expression of IFNG and CD40LG responded quadratically (p < .05), peaking at 6–9 g/kg dietary inclusion of SB, respectively. Other studied variables were not affected by dietary SB inclusion (p > .05). Feeding dry SB berries up to 12 g/kg of diet did not improve the zootechnical variables of healthy commercial-strain broilers in this study. 相似文献
3.
Sarah K. Oettl Jana Gerstmeier Shafaat Y. Khan Katja Wiechmann Julia Bauer Atanas G. Atanasov Clemens Malainer Ezzat M. Awad Pavel Uhrin Elke H. Heiss Birgit Waltenberger Daniel Remias Johannes M. Breuss Joel Boustie Verena M. Dirsch Hermann Stuppner Oliver Werz Judith M. Rollinger 《PloS one》2013,8(10)
In vitro screening of 17 Alpine lichen species for their inhibitory activity against 5-lipoxygenase, microsomal prostaglandin E2 synthase-1 and nuclear factor kappa B revealed Cetrelia monachorum (Zahlbr.) W.L. Culb. & C.F. Culb. As conceivable source for novel anti-inflammatory compounds. Phytochemical investigation of the ethanolic crude extract resulted in the isolation and identification of 11 constituents, belonging to depsides and derivatives of orsellinic acid, olivetolic acid and olivetol. The two depsides imbricaric acid (4) and perlatolic acid (5) approved dual inhibitory activities on microsomal prostaglandin E2 synthase-1 (IC50 = 1.9 and 0.4 µM, resp.) and on 5-lipoxygenase tested in a cell-based assay (IC50 = 5.3 and 1.8 µM, resp.) and on purified enzyme (IC50 = 3.5 and 0.4 µM, resp.). Additionally, these two main constituents quantified in the extract with 15.22% (4) and 9.10% (5) showed significant inhibition of tumor necrosis factor alpha-induced nuclear factor kappa B activation in luciferase reporter cells with IC50 values of 2.0 and 7.0 µM, respectively. In a murine in vivo model of inflammation, 5 impaired the inflammatory, thioglycollate-induced recruitment of leukocytes to the peritoneum. The potent inhibitory effects on the three identified targets attest 4 and 5 a pronounced multi-target anti-inflammatory profile which warrants further investigation on their pharmacokinetics and in vivo efficacy. 相似文献
4.
Atanas G. Atanasov Jian N. Wang Shi P. Gu Jing Bu Matthias P. Kramer Lisa Baumgartner Nanang Fakhrudin Angela Ladurner Clemens Malainer Anna Vuorinen Stefan M. Noha Stefan Schwaiger Judith M. Rollinger Daniela Schuster Hermann Stuppner Verena M. Dirsch Elke H. Heiss 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are clinically used to counteract hyperglycemia. However, so far experienced unwanted side effects, such as weight gain, promote the search for new PPARγ activators.Methods
We used a combination of in silico, in vitro, cell-based and in vivo models to identify and validate natural products as promising leads for partial novel PPARγ agonists.Results
The natural product honokiol from the traditional Chinese herbal drug Magnolia bark was in silico predicted to bind into the PPARγ ligand binding pocket as dimer. Honokiol indeed directly bound to purified PPARγ ligand-binding domain (LBD) and acted as partial agonist in a PPARγ-mediated luciferase reporter assay. Honokiol was then directly compared to the clinically used full agonist pioglitazone with regard to stimulation of glucose uptake in adipocytes as well as adipogenic differentiation in 3T3-L1 pre-adipocytes and mouse embryonic fibroblasts. While honokiol stimulated basal glucose uptake to a similar extent as pioglitazone, it did not induce adipogenesis in contrast to pioglitazone. In diabetic KKAy mice oral application of honokiol prevented hyperglycemia and suppressed weight gain.Conclusion
We identified honokiol as a partial non-adipogenic PPARγ agonist in vitro which prevented hyperglycemia and weight gain in vivo.General significance
This observed activity profile suggests honokiol as promising new pharmaceutical lead or dietary supplement to combat metabolic disease, and provides a molecular explanation for the use of Magnolia in traditional medicine. 相似文献5.
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Formation, maintenance and consequences of the imprint at the mating-type locus in fission yeast
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Mating-type switching in the fission yeast Schizosaccharomyces pombe is initiated by a strand-specific imprint located at the mating-type (mat1) locus. We show that the imprint corresponds to a single-strand DNA break (SSB), which is site- but not sequence-specific. We identified three novel cis-acting elements, involved in the formation and stability of the SSB. One of these elements is essential for a replication fork pause next to mat1 and interacts in vivo with the Swi1 protein. Another element is essential for maintaining the SSB during cell cycle progression. These results suggest that the DNA break appears during the S-phase and is actively protected against repair. Consequently, during the following round of replication, a polar double-strand break is formed. We show that when the replication fork encounters the SSB, the leading-strand DNA polymerase is able to synthesize DNA to the edge of the SSB, creating a blunt-ended recombination intermediate. 相似文献
8.
The power coefficient k decreases along evolution in an allometric relationship between the oxygen consumption rate and the body mass of animals. This theoretical study investigated the role of the power coefficient k and its behavior along evolution. The animals were organized in three groups according to the values of the power coefficient k as follows: (I) from unicellular Prokaryotes to Eukaryotes; (II) from Mytilus and Annelida to Pisces; (III) from Reptilia to Mammals and Aves. At the beginning of each animal group (stage), the value of k was close to 0.9-1.0 and at the end of the stage it was close to 0.67-0.70. Exponential sharp increase of the power coefficient k was observed during the biological transition from Protozoa to simply organized Metazoa and in the transition from Poikylothermic to Homothermic organisms (e.g. from Pisces to Reptilia). Also, when using the periodogram regression analysis, a cyclic (periodic) pattern in this increase was observed (i.e. period T approximately 8-11 units, P<0.05). It was postulated that the power coefficient k, as with the coefficient a, might represent the increase of complexity of animal organization within each group. 相似文献
9.
Relationship between type and age of the inoculum cultures and betalains biosynthesis by Beta vulgaris hairy root culture 总被引:1,自引:0,他引:1
From a study of the relationship between the type and age of the inocula, and the growth and biosynthesis of betalains in a Beta vulgaris hairy root culture, the best results were achieved with a 14 d inoculum grown in submerged culture giving 42 mg betalains (16 mg betacyanins and 26 betaxanthins) and 1.5 g dry biomass in 40 ml medium. 相似文献
10.
Atanas V. Koulov Paul LaPointe Bingwen Lu Abbas Razvi Judith Coppinger Meng-Qiu Dong Jeanne Matteson Rob Laister Cheryl Arrowsmith John R. Yates III William E. Balch 《Molecular biology of the cell》2010,21(6):871-884
The activator of Hsp90 ATPase 1, Aha1, has been shown to participate in the Hsp90 chaperone cycle by stimulating the low intrinsic ATPase activity of Hsp90. To elucidate the structural basis for ATPase stimulation of human Hsp90 by human Aha1, we have developed novel mass spectrometry approaches that demonstrate that the N- and C-terminal domains of Aha1 cooperatively bind across the dimer interface of Hsp90 to modulate the ATP hydrolysis cycle and client activity in vivo. Mutations in both the N- and C-terminal domains of Aha1 impair its ability to bind Hsp90 and stimulate its ATPase activity in vitro and impair in vivo the ability of the Hsp90 system to modulate the folding and trafficking of wild-type and variant (ΔF508) cystic fibrosis transmembrane conductance regulator (CFTR) responsible for the inherited disease cystic fibrosis (CF). We now propose a general model for the role of Aha1 in the Hsp90 ATPase cycle in proteostasis whereby Aha1 regulates the dwell time of Hsp90 with client. We suggest that Aha1 activity integrates chaperone function with client folding energetics by modulating ATPase sensitive N-terminal dimer structural transitions, thereby protecting transient folding intermediates in vivo that could contribute to protein misfolding systems disorders such as CF when destabilized. 相似文献