Purification, characterization and preliminary X-ray study of fumarase from Saccharomyces cerevisiae.

Fumarase (fumarate hydratase, EC 4.2.1.2) from Saccharomyces cerevisiae has been purified to homogeneity by a method including acetone fractionation, DEAE ion-exchange and dye-sorbent affinity chromatography. The suggested method allows fumarase purification with a yield higher than 60% and may be used to obtain large enzyme quantities. The native protein consists of four subunits with a approximately 50 kDa molecular mass each and has an isoelectric point at pH 6.5 +/- 0.3. The equilibrium constant for fumarate hydration is about 4.3 (25 degrees C, pH 7.5), the Michaelis constants for fumarate and 1-malate are approximately 30 microM and approximately 250 microM, respectively. The enzyme is activated by substrates and multivalent anions, the activation seems to be of a non-competitive type. The fumarase complex with meso-tartaric acid has been crystallized by the vapor diffusion method. The unit cell parameters are a = 93.30, b = 94.05 and c = 106.07 A, space group P2(1)2(1)2(1). The unit cell contains 2 protein molecules. The crystals diffract to at least 2.6 A resolution and are suitable for X-ray structure analysis.     

Study of the radiation spectra of fast Z-pinches formed during the implosion of wire arrays in the Angara-5-1 facility

Results are presented from measurements of the radiation spectra of the Z-pinch tungsten plasma produced during the implosion of cylindrical wire arrays with a linear mass of 200?C400 ??g/cm and an initial diameter of 12?C20 mm at a current of ??3 MA in the experiments performed at the Angara-5-1 facility. The radiation spectra in the photon energy range of 50?C900 eV were recorded on a UF-4 X-ray film by using a spectrograph with a transmission grating. The radiation spectrum in the photon energy range of 1?C3 keV was recorded using a crystalline panoramic spectrograph. A curtain shutter was used to protect the transmission grating from fast microparticles produced due to the erosion of high-voltage electrodes. The total radiation yield was measured with a thermocouple calorimeter. It is shown that most of the tungsten plasma radiation energy is emitted in the photon energy range of 80?C300 eV. Measurements of the spectral intensity of pinch radiation with a spatial resolution along the pinch radius showed that the effective transverse diameter of the pinch did not exceed 2 mm, which agrees with independent current measurements of the pinch size. The results of measurements of the spectral intensity of pinch radiation were compared with calculations per-formed under the assumption of a stationary homogeneous plasma.     

Kinetics of the dual-action mechanism of narcotic substances: conditions for conservative functioning of enzyme-receptor systems.

We have studied the kinetics of the conservative behavior of systems which are subject to the dual action of an external effector or a negative feedback. Conditions have been found under which the dual-action mechanism produces conservative behavior. Negative feedback alone was shown not to produce the conservative behavior of an enzyme-receptor system.     

Multinuclear blue copper-proteins: the evolutionary design

The review presents both our own and literature data on studies of pathways of evolution of the so-called multinuclear blue copper-proteins (MBCP) that have the domain organization. The MBCP are widely spread in living nature, they have been revealed in cells of archei, bacteria, and eukaryotes. The MBCP composition includes the copper-proteins such different by their properties as oxidases, reductase, blood coagulation factors V and VIII. Most likely, MBCP have been originated from a low-molecular protein-precursor similar topologically with the blue electron-transporting protein of the cupredoxin type, as a result of action of various evolutionary mechanisms: amplification of genes, formation of protein structures by different combinations of domains, a change of size of domains, the segment elongation at the expense of the activational domain, formation and loss of copper-binding centers, variation of amino acid ligands in such centers, the appearance of centers of binding of other proteins, glycosylation, etc.     

Ultrastructural informational analysis of the dynamics of liver cell recovery after performance of a biliodigestive anastomosis in mechanical jaundice]

Hepatic ultrastructure has been studied in dogs at the level of cholestasis and at different time after cholecystenteroanastomosis. Owing to theoretico-informative approach applied in the investigation, it was possible to reveal certain essential disorganization in hepatic ultrastructures on the 7th day after the operation. This phenomenon seems to explain the occurrence of acute hepatic insufficiency at early postoperative stages not infrequently observed in clinic. Changes produced by 30-days' cholestasis are demonstrated to be reversible.     

Hypoderma actaeon: an emerging myiasis in roe deer (Capreolus capreolus)

Subcutaneous larvae of Hypoderma spp. (Diptera: Oestridae) were detected in the dorsal region in 10 roe deer, Capreolus capreolus (Artiodactyla: Cervidae), hunted in central Spain between January and March 2016. All larvae were found in the inner side of the hide during the skinning of the animals. The study of the morphological features of eight larvae of different stages collected from two animals allowed the identification of Hypoderma actaeon Brauer. The small size (4–5 mm) of some of the first instars suggests that the internal lifecycle of H. actaeon may be exclusively subcutaneous. This is the first confirmation of H. actaeon in roe deer; however, further studies to assess the spread of the parasite and to follow the evolution of this myiasis in roe deer are needed.     

The Lower Devonian conodont Pedavis pesavis and the pesavis Zone

Valenzuela-Ríos, 7.1. 1994 10 15 The Lower Devonian conodont Pedavis pesavis and the pesavis Zone.
Records from Europe and Western North America suggest that a diversification of Pedavis faunas took place around the base of what has been called the pesavis Zone. This level is reviewed in comparison to sequences in Western North America and Spain. Hitherto, two different taxa, Pedavis pesavis S.S. and Pedavis striatus (= Icriodus pesavis of Klapper 1969) have been used indiscriminately in defining the base of the pesavis Zone. This revision points out that the chronostratigraphic problems derived from an unknown phylogenetic history of both P. striatus and P. pesavis remain still unsolved, and thii fact challenges the continued use of either taxon as a zonal index for dating and correlating purposes. To improve this situation a new biostratigraphic unit above the delta Zone is proposed, the pandora beta - gilberti unit. This unit is unambiguosly defined, and thus it now enables accurate correlation on a global-scale basis above the delta Zone. Conodonts, biostratigraphy, Lower Devonian, Pyrenees, Nevada .