Evidence for increased hepatic sympathetic nerve activity resulting in hyperglycemia in response to hemorrhage-induced reflex stimulation in anesthetized dogs

To investigate the role of the sympathoadrenal system in glucose mobilization by the liver during hemorrhage, catecholamine (CA) output from both adrenal glands was determined in anesthetized dogs. Venous blood draining from both adrenal glands was combined in a Y-tube that was connected to an electromagnetic flow probe to measure total adrenal venous blood flow. Plasma concentrations of norepinephrine (NE), epinephrine (E), dopamine (DA), and glucose (GL) were determined in various vascular regions. Adrenal CA output (nanograms per minute) under basal conditions was 50.2 +/- 13.6, 181.4 +/- 41.9, and 13.7 +/- 4.8 for NE, E, and DA, respectively. These values were found to increase significantly (P less than 0.05) in response to 5 min of hemorrhage, reaching a maximum output (nanograms per minute) of 663.6 +/- 160.6 (NE), 2503.4 +/- 607.8 (E), and 141.7 +/- 43.7 (DA). Aortic CAs (nanograms per millilitre) increased significantly with a predominant increase in E (0.33 +/- 0.08 to 3.75 +/- 1.03, P less than 0.05). In contrast, increases in portal and hepatic venous CAs (nanograms per millilitre) were characterized by a predominant increase in NE (0.30 +/- 0.06 to 0.64 +/- 0.11 and 0.17 +/- 0.02 to 0.31 +/- 0.07, respectively, P less than 0.05). Hepatic venous and aortic GL concentrations also increased significantly during hemorrhage. Among the various correlations between plasma CA and GL concentrations, the strongest correlation was found between hepatic venous NE and hepatic venous GL (r = 0.804, P less than 0.001). Correlation coefficients obtained with aortic NE and E were weaker but significant (r = 0.603 and r = 0.608, respectively, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fine structure of wide and narrow vertebrate muscle Z-lines. A proposed model and computer simulation of Z-line architecture

A model of the structure of vertebrate Z-lines and Z-line analogs is introduced and supported by evidence from electron microscope studies of wide Z-lines (rat and feline soleus, and feline and canine cardiac muscles), narrow Z-lines (guppy, newt and frog skeletal muscles), and Z-rods (from a patient with nemaline myopathy and from cardiac muscles of aged dog). The model is based on a pair of Z-filaments (termed a Z-unit), which are linked near their centers at a 90 degrees angle and form bridges between neighboring antipolar thin (actin) filaments. A square lattice of four Z-filament pairs (the basic structure of the Z-line, termed a Z-line unit) defines the geometrical position of the I-square unit. In this native state of the Z-line, small square and large square net forms appear in cross-section. Other cross-sectional patterns of Z-lines, including basket-weave and diagonal-square net patterns, can be explained by detachment of the Z-filament from the Z-filament binding region within each Z-filament pair due to chemical or physical stress. Dissection of Z-lines and Z-line analogs with calcium-activated neutral protease provides evidence that the width of all wide Z-line structures is determined by the amount of overlap of antipolar thin filaments from adjacent sarcomeres. Longitudinal patterns of narrow and wide Z-lines are shown and described in relation to the model. To test the proposed model, the dynamics of the Z-line unit structure were computer-simulated. An attempt was made to correlate longitudinal (z direction) and cross-sectional (x and y directions) patterns and to determine the amount of movement of thin or Z-filaments that is required to explain the diversity observed in cross-sectional patterns of Z-lines. The computer simulations demonstrated that the structural transitions among the small square, and therefore large square net, as well as basket-weave and diagonal-square net forms seen in cross-sections could be caused by movements of thin filaments less than 10 nm in any direction (x, y or z).(ABSTRACT TRUNCATED AT 400 WORDS)     

Characteristics of a Urate-Degrading Diamine Oxidase-Peroxidase Enzyme System in Soybean Radicles

The cadaverine content of soybean radicles showed a maximumpeak 3–4 days after planting. The variation coincidedwith radicle uricase activity during seed germination. The uricase activity could not be fractionate when the bufferpH for the extraction was at 6.0. The addition of 1 M KCl orNaCl to the buffer allowed the extraction of the uricase activity,but an addition of 1 M MgCl₂ or BaCl₂ inhibited this enzyme'sactivity. The urate-degrading enzyme system was purified 248-fold permilligram of protein from soybean radicles. The respective K_mvalues of the diamine oxidase activity for cadaverine and ofthe urate-degrading activity for hydrogen peroxide and uratewere 1.25, 2.93 and 50.3 µM. Analysis by gel electrophoresisof the partially purified enzyme fraction revealed that theurate-degrading enzyme system consisted of a peroxidase thatdegrades urate with hydrogen peroxide and a diamine oxidasethat releases hydrogen peroxide. These data are evidence that a urate-degrading diamine oxidaseand peroxidase system exists in soybean radicles and that thereaction rate of urate-degradation is controlled by the concentrationof cadaverine. (Received November 28, 1984; Accepted April 8, 1985)     

Inhibition of Photosynthesis by Sulfite in Mesophyll Protoplasts Isolated from Vicia faba L. in Relation to Intracellular Sulfite Accumulation

Inhibition of photosynthesis by Na₂SO₃ in mesophyll protoplastsisolated from Vicia faba leaves and uptake of sulfite by theprotoplasts were examined at various pH values of the incubationmedium containing Na₂SO₃. As the pH of the incubation mediumlowered, the rate of photosynthesis in the protoplasts decreasedand the amount of sulfite taken up by the protoplasts increased.Most of sulfite accumulated in the protoplasts was not metabolizedduring the dark incubation, as measured with an ion chromatograph.Photosynthetic O₂ evolution by the chloroplasts isolated fromVicia mesophyll protoplasts was inhibited by exogenously-appliedNa₂SO₃ over pH region examined (7.4–9.0). The sulfiteconcentration required for a half inhibition of photosynthesisby the isolated chloroplasts was similar to the intracellularsulfite level required for that by the protoplasts. These resultsindicate that the intracellular sulfite accumulated in the protoplastsin an unmetabolized state is responsible for the inhibitionof protoplast photosynthesis. (Received January 24, 1985; Accepted May 29, 1985)     

Fimbriae from the oral anaerobe Bacteroides gingivalis: physical, chemical, and immunological properties.

Circular dichroism spectra indicated the predominance of beta-sheet structure in Bacteroides gingivalis fimbriae regardless of the presence of sodium dodecyl sulfate. By using a computer program, the alpha-helix, beta-sheet, and beta-turn contents and the remainder were estimated to be 0, 55, 18, and 27%, respectively, judging from the circular dichroism spectra of the fimbriae. Heating for 5 min at 100 degrees C in sodium dodecyl sulfate was necessary to denature the fimbriae into their constituent protein (fimbrilin) monomers with a reduced content of beta-sheet structure. The amino-terminal amino acid sequence of the fimbrilin was different from partial or complete amino acid sequences of fimbrilins so far determined from Bacteroides nodosus, which falls into the same nonfermentative species of the genus Bacteroides as B. gingivalis, and from various other bacteria. Fimbrilin monomers had an isoelectric point of 6.0. Examination of antibodies against fimbriae and sodium dodecyl sulfate-denatured fimbrilin by enzyme-linked immunosorbent assay reinforced a previous notion (F. Yoshimura, K. Takahashi, Y. Nodasaka, and T. Suzuki, J. Bacteriol. 160:949-957, 1984) that different sets of antigenic determinants seemed to be exposed on their surfaces.     

In vitro establishment of human fibroblasts of lysosomal diseases,GM1-gangliosidosis and Sandhoff disease,by transformation with origin-minus SV40 DNA

The permanent human cell lines preserving defects of lysosomal enzymes, G_M1-1019-SV and SA-1077-SV, were established from the respective fibroblasts from patients with G_Ml-gangliosidosis and Sandhoff disease by transfection with replication origin-minus simian virus 40 DNA. These ceils grow rapidly without entering senescence during more than 120 population doublings. The activity of -galactosidase in G_M1-1019-SV and of B-N-acetylhexosaminidase in SA-1077-SV was respectively 40- and 180-fold lower than that of normal fibroblasts.     

Phenazine methosulfate stimulation of ouabain-sensitive Rb+ uptake by HeLa cells: effects of respiratory inhibitors, anaerobiosis, and ascorbate

phenazine methosulfate (PMS) stimulates ouabain-sensitive Rb+ uptake by HeLa cells. This stimulation cannot be attributed to the effect of the dye on the intracellular Na+ or ATP content. Respiratory inhibitors, such as 5 mM NaCN and 5 microM rotenone, and anaerobic conditions enhance the stimulation of Rb+ uptake by PMS. Cellular respiration is stimulated, but lactate production is reduced in the presence of PMS, irrespective of the presence of respiratory inhibitors. Cellular NADH is oxidized markedly on addition of PMS plus inhibitors, but it is not affected by addition of the inhibitors only. In the presence of a high concentration of PMS, PMS-stimulated ouabain-sensitive Rb+ uptake is inhibited by addition of ascorbate. From these results it is concluded that Na+K-pump activity is closely related to the cellular redox state.     

An investigation for the occurrence of C4 photosynthesis in the Cyperaceae from Australia

Two hundred and twenty species of 38 genera in the Cyperaceae from Australia were examined for the possible occurrence of the C₄ photosynthesis and the anatomical features of leaves and culms. The Kranz type of anatomy and the carbon isotope ratios typical of C₄ plants were found in 84 species in the following six genera of four tribes belonging to subfamily Cyperoideae:Bulbostylis, Crosslandia, andFimbristylis (Fimbristylideae);Lipocarpha (Lipocarpheae);Cyperus (Cypereae);Rhynchospora (Rhynchosporeae). The anatomical observation revealed that the C₄ species possessed any one of the three Kranz anatomical types found by previous investigators. It was suggested that in the Cyperaceae the C₄ syndrome evolved independently within several taxa of the subfamily. The relative distribution of C₃ and C₄ species of the Cyperaceae in Australia was investigated by use of floristic data. It was recognized that the C₄ species dominated in the northern part of the continent which was characterized by tropical and subtropical savannas and hot dry areas with summer rainfall, and the C₃ species in the southern part, which contained temperate areas and mediterranean climatic areas with winter rainfall.     

Kinetic studies on the cleavage of oligouridylic acids and poly U by bovine pancreatic ribonuclease A

Kinetic parameters, Km and Vmax for the transesterification of oligouridylic acid, (Up)nU greater than p (n=0-4), by RNase A were measured spectrophotometrically at pH 7.0 and 25 degrees C. The kinetic parameters, pKm and log Vmax increased with increase in the chain length (n), and seemed to be almost constant with substrates having n greater than or equal to 2. The contribution of each subsite to the binding was estimated according to Hiromi's theory. The subsite affinities for (B1, R1, P1)+(B2, R2, P2) and (B3, R3, P3) are 8.03 kcal and 0.72 kcal/mol, respectively, and those for (B4, R4, P4) and (B5, R5, P5) are less than 0.5 kcal/mol. Therefore, we postulate that the size of the RNase A active site is about 3 nucleotides in length. Transesterification of poly U by RNase A was followed spectrophotometrically. The reaction is markedly influenced by ionic strength. At lower ionic strength, the v0-S curve of poly U cleavage was sigmoidal and cooperative, and it became less cooperative at higher ionic strength. Since the estimated Vmax value for poly U cleavage at ionic strength of 0.1 was more than 20 times larger than that of oligouridylic acids cleavage, we propose a non-specific interaction of poly U anion with cationic groups on the surface of the enzyme, modulating the conformation of active site, and thus increasing the activity at low ionic strength. The interaction decreases at higher ionic strength due to the interaction of counter anions with the non-specific sites.