Morphologische,anatomische und palynologische Untersuchungen an der GattungAretiastrum (Valerianaceae)

The fiveAretiastrum species investigated are differentiated by morphological, histological and palynological characteristics from one another and from woodyValeriana species. It seems justified to regardAretiastrum at least as a distinct section ofValeriana but better as a separate genus.

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Morphologische, anatomische und palynologische Untersuchungen an der GattungAretiastrum (Valerianaceae)

     

Isolation and binding properties of leucyl-tRNA synthetase from Escherichia coli MRE 600

Summary A procedure for the large-scale isolation of leucyl-tRNA synthetase from E. coli MRE 600 is described: The enzyme was purified about 320-fold to homogeneity by precipitation with cetyl-trimethyl-ammonium bromide, two consecutive chromatographies on DEAE-cellulose and three on hydroxyapatite with an over-all yield of 4%.The molecular weight of leucyl-tRNA synthetase from E. coli MRE 600 was found to be 99 000 daltons. Binding studies by ultracentrifugation and equilibrium partition showed that the enzyme binds leucine, leucyl-adenylate and tRNA^Leu, each in a 1 : 1 stoichiometry. For ATP only a very weak binding to the enzyme could be observed, which did not allow the evaluation of the complex stoichiometry. The presence of ATP was not required for the binding of leucine or tRNA to leucyl-tRNA synthetase from E. coli MRE 600.     

Kinetics and substrate specificity of the glycanase activity associated with particles of Klebsiella bacteriophage No. 13

There is a glycanase activity associated with the particles of Klebsiella bacteriophage No. 13 which catalyzes hydrolysis of O-β-d-glucopyranosyl-(1 → 4)-β-d-mannopyranose linkages in Klebsiella serotype 13 capsular polysaccharide. The initial glycanase reaction velocity (at 37° and the optimum pH of 7–8) exhibits hyperbolical dependence on low concentrations of substrate, with K_m = 170 μm (in repeating units), and V_max = 140 nmol/min (glucose equivalents, for 10¹⁰ plaque-forming units). The reaction is inhibited by reaction products (type-13 penta- and decasaccharides, one and two repeating-units), and also by the substrate at concentrations above 1mm. Of seventy-four heterologous Klebsiella, and two other bacterial capsular heteropolysaccharides, as well as two substrate derivatives tested, only the Klebsiella serotype-2, -22, and -37 glycans were also depolymerized by the phage-13 enzyme. The reacting polysaccharides consist of repeating units, characteristically containing (a) chain 3eq,1eq → 4eq,1eq dihexopyranosyl sequences around the susceptible linkages, with equatorial hydroxyl and hydroxymethyl groups at C-2 and C′-5 next to them, and (b) branch carboxyl groups that may have to be located within a certain distance from these linkages.     

Murein biosynthesis in ether permeabilized Escherichia coli starting from early peptidoglycan precursors

ETB, ether treated bacteria, from E. coli and other Gram-negative strains, contain in a cell-free system all enzymes necessary for murein biosynthesis. Starting with a variety of combinations of peptidoglycan precursors, high yields of sodium dodecylsulfate (SDS, 4%) insoluble murein or murein like material were synthesized. The amount of newly synthesized SDS insoluble material (NSM) was dependent upon the growing phase at which cells had been harvested for preparation of ETB. This data may provide some insight into the regulation of peptidoglycan biosynthesis.Starting from early peptidoglycan precursors, the cell-free synthesis of NSM was inhibited by specific inhibitors of murein synthesis, such as D-cycloserine, D-fluoroalanine, 2-amino-ethylphosphonate, analogues of D-alanyl-D-alanine and -lactam antibiotics at appropriate concentrations. Some D-alanyl-D-alanine analogues and 4-chlorodiaminopimelic acid were incorporated into NSM in place of their corresponding natural substrates.Abbreviations ETB ether treated bacteria (E. coli) - NSM newly synthesized SDS insoluble material - SDS sodium dodecylsulfate - UDP-MAG UDP-MurNAc-dipeptide, UDP-N-acetylmuramoyl-L-alanyl-D-glutamate - UDP-MAGD UDP-MurNAc-tripeptide, UDP-N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-2,6-diaminopimelate - UDP-MAGDAA UDP-MurNAc-pentapeptide, UDP-N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine - GINAc N-Acetylglucosamine Definitions Murein highly cross-linked bagshaped peptidoglycan (Weidel and Pelzer 1964)     

Arginine phosphate in compound eyes

Summary The steady state levels of various phosphate esters were measured in the compound eyes of two species of decapod crustaceans (Astacus andEupagurus) and of the blowfly (Calliphora). In the crustaceans, free nucleotides—especially ATP—contribute only little to the soluble phosphate fraction. The adenylate charges of all three species are in the range of about 0.8, though the proportion of adenine nucleotides to other organic phosphates differs considerably. The main energy rich phosphate compound in crustacean eyes was found to be arginine phosphate; the ratio ATP/Arg-P is 1:10 inAstacus, and 1:4 inEupagurus; in the blowfly it is near 1:1. Arg-P is considered to play a role as a phosphagen.This investigation was supported by Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 114 (Bionach)     

“Axonal spheroids” in the spinal cord of normal rabbits

Summary Within the gray matter and the white matter of the spinal cord of apparently healthy rabbits, myelinated and unmyelinated axonal swellings, so called axonal spheroids, occur. Most of the spheroids contain mitochondria, dense bodies, vesicles and fragments of the tubular or smooth endoplasmic reticulum. In myelinated spheroids the process of swelling is effected by slippage of the myelin leaflets. At the periphery of the unmyelinated parts of the spheroids, synapses are regularly found. The presynaptic terminal bouton is formed by the spheroid. A few myelinated and unmyelinated spheroids are packed with fine granular material while mitochondria are lacking. The axonal spheroids may represent a physiological, perhaps age dependent phenomenon.Dedicated to Prof. Dr. Berta Scharrer on the occasion of her 70^th birthdayThe author wishes to thank Mrs. Helga Zuther-Witzsch, Mrs. Elisabeth Schöngarth and Miss Hildegard Schöning for excellent technical assistance. Supported by the Deutsche Forschungsgemeinschaft, Projekt Le 69/7-13     

Relationship between the subcellular distribution of delta-9-tetrahydrocannabinol and its metabolites in rat brain and the duration of the effect on motor activity.

Female rats were injected intraperitoneally with 10 mg/kg of unlabelled delta-9-tetrahydrocannabinol (Δ⁹-THC) and their locomotor activity was recorded every 15 minutes for 12 hours. The maximum depressant effect was observed between the first and fourth hour and had completely disappeared by the eighth hour of treatment. In parallel experiments rats were injected with 10 mg/kg of ³H-delta-9-THC and decapitated either one, four or twelve hours later. The concentrations of unchanged delta-9-THC and metabolites in brain subcellular fractions were determined using thin layer chromatographic methods. There were no substantial differences in the relative specific activities of delta-9-THC or 11-OH-delta-9-THC between all fractions except cytosol, indicating no preferential site of accumulation. However, when the synaptosomal fraction was osmotically shocked, the concentration of delta-9-THC in nerve-ending membranes was markedly higher than that in vesicles or soluble fraction. Our results $\text{in vivo}$ showed a marked decline, over twelve hours, in the relative specific activities of delta-9-THC and 11-OH-delta-9-THC with a concomitant increase in the concentration of highly polar, non-extractable metabolites in all subfractions. It is suggested that the diminution of the depressant effect on motor activity may be related to the formation of highly polar, pharmacologically inactive metabolites of delta-9-THC and/or 11-OH-delta-9-THC inside the brain which do not easily migrate out of the cells.     

A deletion derivative of the kalilo senescence plasmid forms hairpin and duplex DNA structures in the mitochondria of Neurospora.

Summary A novel deletion derivative, kal, of the kalilo senescence plasmid from Neurospora intermedia, was recovered from a culture treated with chloramphenicol. The deletion derivative exists in mitochondria as two different, equally abundant forms: a 2.8 kb duplex DNA molecule kal-2.8) and a 1.4 kb hairpin form kal-1.4). The kal-2.8 plasmid contains the 1366 by terminal inverted repeats and a partially duplicated 102 by segment of the unique sequence of the 8.6 kb kalilo plasmid. In contrast, the kal-1.4 hairpin plasmid appears to result from the folding of single strands that are generated during the replication of kal-2.8. Both forms of kal have covalently linked terminal proteins. Sequence analysis suggests that kal was generated either by slippage of the tip of a growing strand during the replication of kalilo, or by illegitimate recombination between two copies of the plasmid at non-homologous palindromic sequences that might form cruciform structures. In either case, the deletion process was mediated at least in part by an inverted repeat of 5 by in the unique region of kalilo. Since the terminal segments of kalilo DNA that are implicated in plasmid integration might also form cruciform structures, it is possible, but improbable, that the process that generated the first kal molecule is related to that which mediates integration of the plasmid into mitochondrial DNA.     

Hydrogenation with entrapped clostridium spec. LA 1 and observation on its stability

Summary Clostridium spec. La 1 can be entrapped in ENT-110 with reasonable activity for the hydrogenation of ²-enoates or aldehydes with hydrogen gas. This catalyst can be stored for several months. In operation at 35° C it has a half-life of about 10 days. The catalyst can be reisolated and reused. The presence of an organic solvent such as decalin does not reduce its stability.