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271.
Július Hodosy Peter Celec Daniela Ostatníková Marieta Cagánová Zdeněk Putz Peter Baláž Matúš Kúdela 《Central European Journal of Biology》2009,4(2):186-189
Androgens are known to affect cognitive functions via organizational and activational effects. It is unknown whether the effects
are mediated via the androgen receptor or after conversion to estradiol with aromatase via estrogen receptors. The aim of our study was to
find out whether testosterone affects spatial memory directly or through its metabolite estradiol. Rats were treated with
testosterone; with testosterone and the aromatase blocker anastrozole or saline. An 8 radial arm maze was used for testing
spatial memory twice daily for 4 days. Each arm was baited with food, and the ability of animals to learn the location of
food was assessed. Testosterone treated rats and control rats achieved comparable coefficients of spatial memory, although
the plasma levels of testosterone differed markedly. Anastrozole treatment resulted in the worst performance in the maze.
The differences between groups did not reach the level of significance. It can be concluded that aromatase and, thus, the
conversion of testosterone to estradiol may play a role in spatial memory, as pharmacological blockade of aromatase led to
a decrease in maze performace of adult male rats. Detailed molecular mechanisms should be the focus of further studies. 相似文献
272.
Bacteriocin-producing strain of Enterococcus faecium EK 13 with probiotic character and its application in the digestive tract of rabbits 总被引:2,自引:0,他引:2
Andrea Lauková Viola Strompfová Viera Skřivanová Zdeněk Volek Eva Jindřichová Milan Marounek 《Biologia》2006,61(6):779-782
Enterococcus faecium EK 13 is a bacteriocin-enterocin A producing strain with probiotic properties. In this study its colonization, stability
and effect on microflora in rabbits was studied as well as its influence on zootechnical parameters. Fifty rabbits of both
sexes (HYPLUS, 30-day old; after weaning) were divided into control (CG) and experimental (EG) groups. They were fed a standard
diet. Moreover, 25 rabbits in EG were fed daily (for 4 weeks) 15 g (separate doses ∼1.6 g) of lyophilized EK13 strain (rifampicin
resistant variant — rifR; 109 cfu/g) dissolved in drinking water. After cessation of EK13 (rifR) strain application, the rabbits in both groups were fed a standard diet for the next 2 weeks. Sampling was performed in
double on day 0 (at the beginning of experiment), weekly during EK13 (rifR) strain application as well as on week 1 and 2 after cessation of EK13 (rifR) strain application. The counts of EK13 (rifR) strain reached 7.1 ± 2.6 log10 cfu/g after 4 weeks and even on week 2 after its cessation the counts 5.6 ± 2.3 log10 cfu/g were determined. The total counts of enterococci in the rabbits were already increased in EG comparing with CG (p < 0.05); even 2 weeks after EK13 (rifR) strain cessation, their counts in EG were 7.2 ± 2.6 log10 cfu/g (p < 0.001). Enterococci in CG reached at the same time the value 3.7 ± 2.6 log10 cfu/g. The counts of E. coli were significantly reduced in EG during 4 weeks (p < 0.05, p < 0.001). Even 2 weeks after EK13 (rifR) strain cessation significant difference in E. coli counts between CG and EG was detected (p < 0.001). Enterobacteria in EG were significantly reduced (p < 0.001). Average daily gain in EG was 41.0 ± 3.83 in comparison to CG (40.6 ± 3.72); it means almost the same; although
rabbits in EG showed higher feed intake per kg of gain than rabbits in CG. Preliminary results demonstrated that EK13 is a
perspective probiotic candidate for rabbits.
Presented at the Second Probiotic Conference, Košice, 15–19 September 2004, Slovakia. 相似文献
273.
Vendula Havlíčková Vilma Kaplanová Hana Nůsková Zdeněk Drahota Josef Houštěk 《BBA》2010,1797(6-7):1124-1129
The subunit ε of mitochondrial ATP synthase is the only F1 subunit without a homolog in bacteria and chloroplasts and represents the least characterized F1 subunit of the mammalian enzyme. Silencing of the ATP5E gene in HEK293 cells resulted in downregulation of the activity and content of the mitochondrial ATP synthase complex and of ADP-stimulated respiration to approximately 40% of the control. The decreased content of the ε subunit was paralleled by a decrease in the F1 subunits α and β and in the Fo subunits a and d while the content of the subunit c was not affected. The subunit c was present in the full-size ATP synthase complex and in subcomplexes of 200–400 kDa that neither contained the F1 subunits, nor the Fo subunits. The results indicate that the ε subunit is essential for the assembly of F1 and plays an important role in the incorporation of the hydrophobic subunit c into the F1-c oligomer rotor of the mitochondrial ATP synthase complex. 相似文献
274.
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276.
Ryšlavá H Kalendová A Doubnerová V Skočdopol P Kumar V Kukačka Z Pompach P Vaněk O Slámová K Bojarová P Kulik N Ettrich R Křen V Bezouška K 《The FEBS journal》2011,278(14):2469-2484
Fungal β-N-acetylhexosaminidases are inducible extracellular enzymes with many biotechnological applications. The enzyme from Penicillium oxalicum has unique enzymatic properties despite its close evolutionary relationship with other fungal hexosaminidases. It has high GalNAcase activity, tolerates substrates with the modified N-acyl group better and has some other unusual catalytic properties. In order to understand these features, we performed isolation, biochemical and enzymological characterization, molecular cloning and molecular modelling. The native enzyme is composed of two catalytic units (65 kDa each) and two propeptides (15 kDa each), yielding a molecular weight of 160 kDa. Enzyme deglycosylated by endoglycosidase H had comparable activity, but reduced stability. We have cloned and sequenced the gene coding for the entire hexosaminidase from P. oxalicum. Sufficient sequence identity of this hexosaminidase with the structurally solved enzymes from bacteria and humans with complete conservation of all catalytic residues allowed us to construct a molecular model of the enzyme. Results from molecular dynamics simulations and substrate docking supported the experimental kinetic and substrate specificity data and provided a molecular explanation for why the hexosaminidase from P. oxalicum is unique among the family of fungal hexosaminidases. 相似文献
277.
Marine sponges are frequently inhabited by a wide range of associated invertebrates, including caridean shrimps. Symbiotic shrimps are often considered to be commensals; however, in most cases, the relationship with sponge hosts remains unclear. Here we demonstrate that sponge-inhabiting shrimps are often parasites adapted to consumption of sponge tissues. First, we provide detailed examination of morphology and stomach contents of Typton carneus (Decapoda: Palaemonidae: Pontoniinae), a West Atlantic tropical shrimp living in fire sponges of the genus Tedania. Remarkable shear-like claws of T. carneus show evidence of intensive shearing, likely the result of crushing siliceous sponge spicules. Examination of stomach contents revealed that the host sponge tissue is a major source of food for T. carneus. A parasitic mode of life is also reflected in adaptations of mouth appendages, in the reproduction strategy, and in apparent sequestration of host pigments by shrimp. Consistent results were obtained also for congeneric species T. distinctus (Western Atlantic) and T. spongicola (Mediterranean). The distribution of shrimps among sponge hosts (mostly solitary individuals or heterosexual pairs) suggests that Typton shrimps actively prevent colonisation of their sponge by additional conspecifics, thus protecting their resource and reducing the damage to the hosts. We also demonstrate feeding on host tissues by sponge-associated shrimps of the genera Onycocaris, Periclimenaeus, and Thaumastocaris (Pontoniinae) and Synalpheus (Alpheidae). The parasitic mode of life appears to be widely distributed among sponge-inhabiting shrimps. However, it is possible that under some circumstances, the shrimps provide a service to the host sponge by preventing a penetration by potentially more damaging associated animals. The overall nature of interspecific shrimp-sponge relationships thus warrants further investigation. 相似文献
278.
Frédéric Reymond Christine Vollet Zdeněk Plichta Daniel Horák 《Biotechnology progress》2013,29(2):532-542
This article describes the preparation of tosyl‐activated nonmagnetic poly(2‐hydroxyethyl methacrylate‐co‐glycidyl methacrylate) [P(HEMA‐GMA)] microspheres by dispersion polymerization and tosyl‐activated magnetic poly(2‐hydroxyethyl methacrylate‐co‐ethylene dimethacrylate) [P(HEMA‐EDMA)] microspheres by multistep swelling polymerization method and precipitation of iron oxide inside the pores. These new approaches show that monodisperse microspheres, 2.3 µm, respectively 4.1 µm, in diameter can be produced in high yields avoiding aggregation and with the advantage of being free of aromatic moieties. To demonstrate their potential for diagnostic applications, both types of microparticles have been coated with capture and detection antibodies (DAs), respectively. Immunoassay protocols have then been developed for the dosage of ferritin using an automated affinity platform combining microchannel chips and electrochemical detection. The assay performance using the above magnetic microspheres has been compared with that obtained with commercial tosyl‐activated beads. Finally, the possibility to combine functionalized magnetic and nonmagnetic microspheres has been evaluated in view of amplifying the number of enzymatic labels in the immuno‐complex. At a ferritin concentration of 119.6 ng/mL, a signal‐to‐noise ratio of 150.5 is obtained using 0.2 mg/mL of anti‐ferritin‐coated P(HEMA‐GMA)‐DA microspheres against a value of 158.8 using free DA in solution. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 532–542, 2013 相似文献
279.
Andrea Kulhánková Lucie Cahlíková Zdeněk Novák Kateřina Macáková Jiří Kuneš Lubomír Opletal 《化学与生物多样性》2013,10(6):1120-1127
The bulbs of Zephyranthes robusta (Amaryllidaceae) have been extensively analyzed for their chemical constituents, resulting in the isolation of 13 alkaloids. The chemical structures of the isolated compounds were elucidated by mass‐spectrometric, and 1D‐ and 2D‐NMR spectroscopic experiments. The complete NMR assignments were achieved for hippeastidine. All isolated alkaloids were evaluated for their erythrocytic acetylcholinesterase and serum butyrylcholinesterase inhibitory activities using the Ellman's method. Significant acetylcholinesterase inhibition activity was exhibited by 8‐O‐demethylmaritidine (IC50(HuAChE) 28.0±0.9 μM ). 相似文献
280.