This study has observed possible effect of ellagitannins - compounds from pomegranate on process of steroidogenesis in ovaries. The aim of the study was to investigate the possible effect of punicalagin on secretion of steroid hormones - progesterone, androstenedione, testosterone and 17β-estradiol by ovarian fragments of rabbits in vitro. Ovarian fragments from sexually mature female New Zealand white rabbits (n=20) were incubated without (control group) or with punicalagin at various doses 1, 10 and 100 μg.ml−1 for 24 h. Hormones were evaluated by ELISA (The Enzyme-Linked Immunosorbent Assay). Data showed that progesterone and 17β-estradiol (but not androstenedione and testosterone) release by rabbit ovarian fragments was significantly affected by punicalagin addition at various doses. Punicalagin (at 100 μg.ml-1) significantly (P<0.05) increased progesterone secretion. On the other hand, the release of 17β-estradiol was significantly (P<0.005) decreased by punicalagin addition (at 10 μg.ml-1). Our results suggest that punicalagin could have dose-dependent impact on secretion of steroid hormones progesterone and 17β-estradiol by rabbit ovarian fragments and it may be effector in process of ovarian steroidogenesis., D. Packova, A. A. Carbonell-Barrachina, A. Kolesarova., and Obsahuje bibliografii
Nereis diversicolor O.F. Müller and N. succinea Frey et Leuckart (Polychaeta, Nereidae) living in brackish shallow areas in Denmark are naturally infected with tetractinomyxon actinospores. Infected Nereis spp. were experimentally fed to various potential fish hosts, and the actinosporean stages developed into myxosporean stages of Ellipsomyxa gobii Køie, 2003 (Ceratomyxidae) in the gallbladder of the common goby Pomatoschistus microps (Krøyer) (Gobiidae). The European eel Anguilla anguilla (L.), three-spined stickleback Gasterosteus aculeatus L., small sand eel Ammodytes tobianus L., flounder Platichthys flesus (L.), European plaice Pleuronectes platessa L. and common sole Solea solea (L.) did not become experimentally infected. In Danish shallow brackish areas P. microps is naturally infected with E. gobii, in some areas with a prevalence >90%. We compared small subunit ribosomal DNA sequences of the actinosporean with E. gobii from P. microps. Sequences were identical, which further verifies that both forms belong to the same organism. This is the first myxozoan two-host life cycle in the marine environment.
A new myxosporean species Ellipsomyxa gobii gen. et sp. n. is described from the common goby Pomatoschistus microps (Krøyer) (Perciformes, Gobiidae). Plasmodia with long branched pseudopodia in the gallbladder develop to subspherical bisporous plasmodia. The myxospores were found in the gallbladder, and the hepatic and bile ducts. The new genus is characterised by the morphology of the myxospores. The myxospores have smooth thin valves elongated in the direction perpendicular to the plane of the straight central transverse indistinct sutural line. The two spherical polar capsules open some distance from the sutural line on opposite sides. The new genus thereby differs from Leptotheca Thélohan, 1895. Ellipsomyxa gobii is tentatively placed in the Ceratomyxidae.
The study addresses a contact problem of a thin elastic (isotropic, incompressible and homogeneous) layer bonded to a rigid plane foundation and indented by a rigid frictionless punch in the form of an elliptical paraboloid. Given the total load, approximate analytical results for the contact ellipse, penetration depth and contact pressure distribution are presented. and Obsahuje seznam literatury
O tom jak se rodily první přístupy k udržení horkého fúzního plazmatu pomocí silných elektrických a magnetických polí., Through his whole scientific career, carried out mainly at FTI Kharkov in the Soviet Union, O. A. Lavrentev (1926-2011) studied thermonuclear plasma confinement. Initially an electrostatic confinement and later a magnetic electrostatic plasma confinement was proposed by him. However, he did not describe the transition from the first to the second type of confinement, e. g., from the spherical concentric purely electrostatic trap to the magnetic trap formed by spindle cusp fields with its slits plugged by electrostatic fields, which represents the simplest type of an electromagnetic trap. This article offers a hypothesis of how O. A. Lavrentev transformed the earlier concept into the later one., Milan Řípa, Miroslav Šos., and Obsahuje bibliografii
Pheophytin (Pheo) is structurally constituted as to make possible certain reactions, previously given very little attention, which appear to play crucial roles in the initial electron transfer (ET) processes. The transformations involve enolisation with subsequent formation of mono- and di-iminium cations at the Pheo core. The important impact of these ions on ET from chlorophyll (Chl) to Pheo and then to quinone are evaluated. These insights rationalise the long-standing enigmas of fast transfer, across gap ET, activation-less aspect, and essential lack of reversibility. Comparisons are made to other important areas of iminium involvement, e.g. chemistry of vision, polyaniline doping, and DNA alkylation.