Inhibition of mitochondrial ATP-synthetase by redox-agents]

Effects of phenol and phenothiazine on ATP synthesis and electron transport in submitochondrial particles were studied. Nitrophenols and phenothiazines inhibited ATP synthesis without notable effect on electron transport. On the contrary chlorphenols equally decreased the velocities of electron transport and ATP synthesis. The inhibitors studied showed the properties of electron acceptors in relation to the radicals, their acceptor properties corresponding to their ability to inhibit ATP synthesis.     

Formation of the vascular system of developing bean (Phaseolus limensis L.) seeds according to nuclear magnetic resonance microtomography

1H magnetic resonance microtomography imaging was applied to study vascular systems in developing bean (Phaseolus limensis L.) seeds. Using the gradient echo method, we recorded 2D tomographic sections in the sagittal and axial planes of the fruits sampled from a vegetating plant on days 10, 17, 24, and 31 after fertilization. Any vascular connection between the tissues of maternal plant (bean pod and seed coat) and the embryo were undetectable. The embryo has an autonomous branched network of procambial strands in the cotyledons, converging to the embryonic axis. The bean pods are covered with a network of vascular bundles; large vascular strands run along the dorsal and ventral sutures. The seed coat vascular bundles are formed in the process of seed ripening and are represented by a developed vascular system multiply branching in the middle part of the ground parenchyma at the stage of physiological maturity. They are connected with the source of assimilates via the lateral pod veins and a large vascular bundle, entering the seed below the hilum via the placenta. Assimilates enter the external part of the seed coat, which contains no vascular bundles, via the funiculus vascular bundles and hilum tissue.     

Cation transport and content in serum-stimulated CHO-773 cells. II. Late changes in rubidium influx and intracellular potassium content

Serum stimulation of stationary cultures of Chinese hamster ovary cells CHO-K1 (clone 773) is accompanied by sustained increase in ouabain-sensitive rubidium (potassium) influx which results in the elevation of intracellular potassium content from 0.5-0.6 to 0.7-0.8 mmole per gram of protein. Cytofluorometric studies of serum-stimulated CHO-773 cultures have shown that the intracellular potassium increase is necessary for successful G1----S progression. The elevation of intracellular potassium was found to occur simultaneously with the cellular protein growth. Cycloheximide (10 micrograms/ml) does not influence the early Na,K-ATPase activation induced by serum; however, it abolishes the sustained increase of both rubidium influx and intracellular potassium content. In serum stimulated cells ouabain increases the potassium efflux; this ouabain effect is not observed after S phase, when rubidium (potassium) influx decreases and intracellular potassium content stops growing.     

L-Glutamate oxidase from Streptomyces cremeus 510 MGU: growth media optimization for the enhancement of the producer fermentative activity]

The investigation was devoted to culture conditions optimization aimed to maximum secretion of extracellular L-glutamate oxidase by Streptomyces cremeus 510 MGU. It was shown that Ca ions at the concentration 5-20 mM and 0.1% ammonium sulphate enhanced activity of extracellular enzyme to 4 folds. L-glutamate acid supplement had no effect on enzyme activity. Influence of some bivalent cations and aeration regimes on L-glutamate oxidase activity was investigated. Growth media optimization along with screening of active variants resulted with isolation of the strain with L-glutamate oxidase activity about 2 U/mL Rate of peroxide degradation in the presence of filtrated culture of S. cremeus was determined by chemiluminescence method.     

Ultrastructure of the capillaries of nerve tissue transplants growing in the anterior chamber of the eye

Blood capillaries have been studied electron microscopically in the areas of grafts (rat embryonal hippocamp and septal cerebral parts transplanted to mature rats) containing mainly nervous, glial or connective tissue cells. Certain differences in the capillary wall structure have been revealed. In areas with a great concentration of nervous cells, the blood capillaries are characterized by a dense arrangement of cellular elements in their walls, a continuous layer of the glial end-feet, this is specific for the CNS capillaries providing the blood--brain barrier. In peripheral area of the grafts, where glial elements predominate, the capillaries have loose arrangement of the mural cellular elements, great endotheliocyte activity, thick connective tissue tunic, lack of a dense glial surrounding. These characteristics make dubious the statement whether these capillaries possess the blood--brain barrier function. In places where connective tissue cells make aggregates, the capillaries do not possess the barrier properties because of perforations and fenestrae in endothelium and interruptions of the basal membrane, absence of pericapillary glial elements. All types of the capillaries demonstrate certain signs of a high functional activity. Formation of the capillary structure depends on the surrounding tissue.     

Comparative Analysis of the Results of a Stepped Running Test Performed in the Vertical and Horizontal Positions

Physiological reactions and energy expenditure during a treadmill test with an increasing load were compared in subjects performing the test in the vertical and the horizontal positions. The subjects performing the test in standing and lying positions exhibit essentially similar but quantitatively different physiological changes, which permits correct dosing of cyclic locomotion in a lying position after some corrections are made. This may be used in rehabilitation of bedridden patients after long-term immobilization and in other cases of disturbed motor activity.     

Peculiarities of erythropoiesis in patients with chronic renal failure

In 600 patients suffering from chronic renal insufficiency the cellularity of bone marrow, erythroid cells proliferative activity, erythroid cells destruction and iron incorporation rate, data of ferrokinetics, intracellular iron distribution, porphyrin synthesis rate were examined. On the basis of the obtained data the suggestion is put forward that metabolic disturbances are important in anemia development in uremic patients. One of the aspects of this problem is the role of disorders in the protein turnover causing changes in the synthesis of globin and porphyrin which are the primary components for heme synthesis. Special importance is attached to the changes in iron turnover, i.e. to its redistribution between stromal and heme pools.     

Cytogeography of the Phleum pratense group (Poaceae) in the Carpathians and Pannonia

Cytogeographical variability within the Phleum pratense group in the Carpathians and adjacent part of Pannonian lowland, based on 132 populations analysed by flow cytometry, is described. Only diploid and hexaploid plants were detected among 635 samples from the studied area. Diploids were found to be less frequent (127 plants, 20%) than hexaploids (508, 80%). With the exception of the single pure diploid population, diploids always co-occured with hexaploids (30 localities, 22.7%). The majority of populations (101, 76.5%) consisted of hexaploid plants. Most mixed populations occur in the Western Carpathians (26). In the Eastern Carpathians, mixed populations are much rarer, with three populations in Ukraine and one in Romania. In the Southern Carpathians, only hexaploids occur. The conventional taxonomic concept of the two species, diploid P. bertolonii and hexaploid P. pratense , was followed in spite of their sympatric occurence. Distribution maps based on chromosome number data from previous studies and on ploidy level estimates are given for both species in the studied area. The pattern of different distribution of the two taxa within the Carpathians is discussed.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 475–485.