Changes in the venous vessels capacitance in the cat forepaw in response to neurohumoral stimuli

The trend in changes of the cat forepaw vessels' capacity was found to practically not differ from the trend in shifts in the vena cava anterior basin's capacity: in both areas the capacity decreases in response to pressor neurogenic stimuli and decreases or increases under the effects of pressor and depressor humoral stimuli. The data obtained suggest that the trend in shifts of the vena cava anterior basin's capacity under the effects of pressor humoral stimuli mainly depends on the skin-muscular area's vessels, whereas the trend in shifts of the vena cava anterior basin's capacity under the effects of depressor humoral stimuli depends, apparently, on the shifts in the brain vessels' capacity function.     

Prolonged feeding of terrestrial isopod (Porcellio scaber, Isopoda, Crustacea) on TiO (2) nanoparicles. Absence of toxic effect

Nanoparticles of titanium dioxide are one of most widely used nanomaterials in different products in everyday use and in industry, but very little is known about their effects on non- target cells and tissues. Terrestrial isopods were exposed to food dosed with nano-TiO(2) to give final nominal concentration 1000 and 2000 μg TiO(2)/g dry weight of food. The effects of ingested nano-TiO(2) on the model invertebrate Porcellio scaber (Isopoda, Crustacea) after short-term (3 and 7 days) and prolonged (14 and 28 days) dietary exposure was assessed by conventional toxicity measures such as feeding rate, weight change and mortality. Cell membrane destabilization was also investigated. No severe toxicity effects were observed after 3, 7, 14 or 28 days of dietary exposure to nano-TiO(2), but some animals, particularly those exposed to lower concentrations of nanoparticles, had severely destabilized digestive cell membranes. It was concluded that strong destabilization of the cell membrane was sporadic, and neither concentration- nor time-related. Further research is needed to confirm this sporadic toxic effect of nanoparticles.     

Optimization and use of a spectrophotometric method for determining polysaccharides in <Emphasis Type="Italic">Echinacea purpurea</Emphasis>

Echinacea purpurea is one of the most widely used immunostimulant plants. Its main active compounds are polysaccharides, glycoproteins, caffeic acid derivatives, alkamides, and melanins. The article describes an optimized extraction procedure that enables spectrophotometric quantification of polysaccharides from Echinacea purpurea. The extraction procedure can be widely applied as it demonstrated to be useful for determining polysaccharide content in flowers and leaves, in summer and autumn plants, in plants with green and red stem, and in plants from two different plantations. A significantly higher content of polysaccharides in flowers in comparison to leaves, as well as in plants with green stems in comparison to plants with red stems was determined. Statistical differences were absent in plants collected in different seasons and growing at different plantations.     

Electron tomography of fusiform vesicles and their organization in urothelial cells

The formation of fusiform vesicles (FVs) is one of the most distinctive features in the urothelium of the urinary bladder. FVs represent compartments for intracellular transport of urothelial plaques, which modulate the surface area of the superficial urothelial (umbrella) cells during the distension-contraction cycle. We have analysed the three-dimensional (3D) structure of FVs and their organization in umbrella cells of mouse urinary bladders. Compared to chemical fixation, high pressure freezing gave a new insight into the ultrastructure of urothelial cells. Electron tomography on serial sections revealed that mature FVs had a shape of flattened discs, with a diameter of up to 1.2 μm. The lumen between the two opposing asymmetrically thickened membranes was very narrow, ranging from 5 nm to 10 nm. Freeze-fracturing and immunolabelling confirmed that FVs contain two opposing urothelial plaques connected by a hinge region that made an omega shaped curvature. In the central cytoplasm, 4-15 FVs were often organized into stacks. In the subapical cytoplasm, FVs were mainly organized as individual vesicles. Distension-contraction cycles did not affect the shape of mature FVs; however, their orientation changed from parallel in distended to perpendicular in contracted bladder with respect to the apical plasma membrane. In the intermediate cells, shorter and more dilated immature FVs were present. The salient outcome from this research is the first comprehensive, high resolution 3D view of the ultrastructure of FVs and how they are organized differently depending on their location in the cytoplasm of umbrella cells. The shape of mature FVs and their organization into tightly packed stacks makes them a perfect storage compartment, which transports large amounts of urothelial plaques while occupying a small volume of umbrella cell cytoplasm.     

Hypoxic postconditioning corrects behavioral abnormalities in a model of post-traumatic stress disorder in rats

Protective effects of the novel technique of hypoxic postconditioning with a hypobaric hypoxia paradigm were studied in "stress-restress" model ofposttraumatic stress disorder in rats. It was shown that repeated (3 times) exposure of rats that survived after severe traumatic stress to mild hypobaric hypoxia (postconditioning mode) efficiently abolished the development of stress-induced anxiety state. Postconditioning had a clear anxiolytic effect both when it was delivered after traumatic stress and after restress, but the intensity of this effect depended on the period ofpathogenesis of the posttraumatic stress disorder, when postconditioning was given. The results indicate that suggested postconditioning model with repetitive mild hypobaric hypoxia exerts potent anxiolytic and stress-protective action.     

Phytoremediation through Bidens pilosa L., a nonhazardous approach for uranium remediation of contaminated water

Abstract

A few plant species are recognized for uranium bioaccumulation, particularly as upper accumulator. Uranium has a dynamic impact on the physiological, biochemical, and photochemical reactions. Therefore, the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), soluble sugar, protein, photochemical reactions, and accumulation of uranium characteristics were studied in Bidens pilosa L. while applying altered concentrations of uranium in the form of C₄H₆O₆U. It was done to measure the capacity of B. pilosa L. to remediate uranium from wastewater. In this study, the results showed that B. pilosa L. not only has the ability of uranium accumulation but it can accumulate in the upper parts i.e. leaves and stem. Overall it can accumulate as much as 1538?mg/kg on a dry weight basis. Uranium accumulation is a complex process which changes both physiological and biochemical index in plant species under different treatments. SOD decreased in leaves and stem in response to all treatments whereas POD and CAT increased at treatment 3 and 72?h up to 1335?μ/g-FW and 47?μ/g-FW at 72?h, respectively. This increase was followed by a downward trend. The correlation coefficient between fluorescence ratio F_v/F_m and the concentrations of uranium treatment were significantly negative i.e. ?0.928. The Fourier transform infrared spectroscopy (FTIR) analysis also highlighted that uranium does not change the basic chemical composition of B. pilosa L., but has an effect on the contents of chemical constituents. From the study, it is concluded that B. Pilosa L. has shown a capacity for uranium enrichment, especially as an upper accumulator.     

Adaptation of muscle fibre types and capillary network to acute denervation and shortlasting reinnervation

We postulated that, in rat extensor digitorum longus muscle (EDL), the length of capillaries per fibre surface area (Lcap/Sfib) and per fibre volume (Lcap/Vfib) could reflect fibre-type transformations accompanied by changes in oxidative metabolic profile and selective fibre-type atrophy. We excised rat EDL muscle 2 weeks after the sciatic nerve was cut (acute denervation; DEDL) and 4 weeks after the nerve was crushed (early reinnervation; REDL) and characterised muscle fibre-type transformation by the expression of myosin heavy-chain isoforms and by succinate dehydrogenase (SDH) and nicotinoamide adenine dinucleotide-tetrazolium reductase (NADH-TR) reactions. The numerical percentage (N/N) and area percentage (A/A) of pure and hybrid fibres and their diameter were determined, as was the A/A of SDH- and NADH-TR-positive fibres. The length of capillaries per fibre length (Lcap/Lfib), Lcap/Sfib and Lcap/Vfib were estimated in REDL and Lcap/Vfib in DEDL. In DEDL, the type 2x and 2b fibres evidently atrophied, with the N/N of type 2x fibres being lower and that of hybrid fibres higher. In REDL, the N/N of hybrid fibres was even higher, consequent to a lower N/N of type 2b fibres; however, fibre diameters approached values of the control EDL. Compared with control EDL, denervated and reinnervated muscles exhibited a higher A/A of oxidative fibres. This is probably the result of fibre-type transformation and selective fibre atrophy. We conclude that capillary length does not change during acute denervation and early reinnervation. The obtained higher values of Lcap/Sfib and Lcap/Vfib are related to changes in muscle fibre cross-sectional area. This study was supported by the Slovenian Research Agency and the Ministry of Education, Youth and Sport of the Czech Republic (KONTAKT grant no. 9-06-6 and grant no. LC06063).     

A new method for the authentication of plant samples by analyzing fingerprint chromatograms

Chemical analysis by high-performance liquid chromatography or capillary electrophoresis of plant pulverized samples, juices or extracts is an excellent method for the authentication of medicinal plant species and their products, particularly when morphological authentication is not possible. In the conventional procedure, chromatograms are integrated and the heights or areas of several peaks are used in a supervised pattern recognition method to confirm the authenticity of the product. We propose a new section approach in analysing chromatograms, where chromatograms are split into sections, which are described by four variables (number of peaks in the section, average retention time of peaks in the section, total area of peaks in the section and average area of peaks in the section), and these variables are then used in statistical analysis. The method is especially useful when the peaks on the chromatogram are not well separated and it is not easy to link individual peaks on one chromatogram with corresponding peaks on other chromatograms. In comparison with the standard procedure, our approach in analyzing chromatographic data of willow-herb (Epilobium and Chamaenerion spp.) extracts was more objective, gave better results and was also easier to perform.     

Surface characteristics of isopod digestive gland epithelium studied by SEM

The structure of the digestive gland epithelium of a terrestrial isopod Porcellio scaber has been investigated by conventional scanning electron microscopy (SEM), focused ion beam–scanning electron microscopy (FIB/SEM), and light microscopy in order to provide evidence on morphology of the gland epithelial surface in animals from a stock culture. We investigated the shape of cells, extrusion of lipid droplets, shape and distribution of microvilli, and the presence of bacteria on the cell surface. A total of 22 animals were investigated and we found some variability in the appearance of the gland epithelial surface. Seventeen of the animals had dome-shaped digestive gland “normal” epithelial cells, which were densely and homogeneously covered by microvilli and varying proportions of which extruded lipid droplets. On the surface of microvilli we routinely observed sparsely distributed bacteria of different shapes. Five of the 22 animals had “abnormal” epithelial cells with a significantly altered shape. In three of these animals, the cells were much smaller, partly or completely flat or sometimes pyramid-like. A thick layer of bacteria was detected on the microvillous border, and in places, the shape and size of microvilli were altered. In two animals, hypertrophic cells containing large vacuoles were observed indicating a characteristic intracellular infection. The potential of SEM in morphological investigations of epithelial surfaces is discussed.     

Synthesis and degradation of hyaluronic acid by bacteria of Streptococcus genus

Modern data on metabolism of hyaluronic acid by bacteria from Streptococcus genus are presented. Several species of bacteria forming capsule from hyaluronic acid, which is analogous to glycosaminoglycan of vertebrates, are considered. Different aspects of hyaluronic acid synthesis are described: biochemical synthesis pathway, genetic basis, regulation of expression of genes belonging to hyaluronic acid synthesis operon. Biological role and physiologic importance of hyaluronic acid for bacteria, including its role in overcoming immune barrier by pathogenic species, are discussed. Process of depolymerization of hyaluronic acid in presence of hyaluronatlyases secreted by certain streptococci is considered. Characteristic of streptococcal enzyme hyaluronatlyase, its mechanism of catalytic effect, and biological function are presented.