Regional histochemical aspects of xanthine oxidase activity in ischemic and reperfused small intestine of the rat

The study describes regional changes of xanthine oxidase and succinate dehydrogenase activities as shown by the ischemic and reperfused small intestine of the rat. The results are obtained with enzyme histochemical methods, including densitometrical verifications, and are substantiated with biochemical enzyme determinations. The decrease of xanthine oxidase activity was best visible in the anoxic duodenum and jejunum, where the findings of histochemical enzyme determinations agreed with those achieved biochemically. The activities of succinate dehydrogenase as measured densitometrically may serve as a further control, considering also the typical intracellular distribution of the reaction products.     

In vivo 31P NMR spectroscopy of energy rich phosphates in the brain of the hyperammonemic rat

Hyperammonemia is a major contributing factor to the neurological abnormalities observed in hepatic encephalopathy and in congenital defects of ammonia detoxication. In rats variable changes in labile energy rich phosphates in the brain have been observed in hyperammonemia using biochemical methods. Using 31P-NMR spectroscopy however no significant changes of the relative concentrations of the energy rich phosphates alpha, beta and gamma-ATP, phosphocreatine, inorganic phosphate and the pH were found in the fronto parietal cortex of the urease treated hyperammonemic rat. Alterations in the metabolites of these compounds do not appear to be a major pathomechanism of ammonia toxicity in this brain area.     

Kinematographische Dokumentation einer amitotischen Zellteilung

Summary Identification of argyrophilic cells, in pancreatic islets of normal rabbits, is accomplished by light and electron microscopy in osmium-fixed plastic-embedded tissues.Fixative, pretreatment and pH of silver nitrate solution were essential for the light microscopic study to reveal argyrophilic cells in osmium-fixed plastic-embedded pancreatic islet tissue. The best result was obtained with Dalton's osmium fixation and buffered silver nitrate methanamine solution at pH 9.O. The cytoplasmic granules of argyrophilic cells generally are densely packed but some of the cells show only sparse silver impregnated granules in the cytoplasm. Occasionally there are some non-argyrophilic granular cells in which, after silver impregnation, the cytoplasm appears clear. There are three kinds of cells in the pancreatic islets, i.e., argyrophilic granular cells, non-argyrophilic granular (clear) cells, and beta cells (situated centrally in the islet and stained light yellow in silver impregnated sections).The cells known as argyrophilic cells in light microscopy can be identified as alpha cells in electron micrographs by comparison of consecutive sections of the same cell.The author would like to express his appreciation to professor Roy C. Swan for his generous guidance.     

DPB1 * BR: an Mhc class II DPB1 allele (DPB1 * 6601) of negroid origin

The nucleotide sequence data reported in this paper have been submitted to the EMBL nucleotide sequence database and have been assigned the accession number X96986. The nameDPB1 ^* 6601 was officially assigned by the WHO Nomenclature Committee in May 1996. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report (Bodmer et al. 1995), names will be assigned to new sequences as they are identified. Lists of such sequences will be published in the following WHO Nomenclature Report     

A consensus linkage map of barley

A consensus linkage map of the barley genome was constructed. The map is based on six doubled haploid and one F₂ population. The mapping data for three of the doubled haploid populations was obtained via the GrainGenes database. To allow merger of the maps, only RFLP markers that produce a single scorable band were included. Although this reduced the available markers by about half, the resultant map contains a total of 587 markers including 87 of known function. As expected, gene order was highly conserved between maps and all but two discrepancies were found in closely linked markers and are likely to result from the small population sizes used for some maps. The consensus map allows the rapid localisation of markers between published maps and should facilitate the selection of markers for high-density mapping in defined regions.     

Recovery of recombinant bacterial plasmids from E. coli transformed with DNA from microinjected mouse cells

We have previously described the isolation of thymidine kinase positive (TK+), human beta-globin gene-containing colonies following co-microinjection of mouse TK- L cells with two recombinant pBR322 plasmids, one containing the TK gene of herpes simplex virus type I (plasmid pXl), and the second containing a human genomic DNA fragment within which is the human beta-globin gene (plasmid pRKl). DNA isolated from one such clone was used in bacterial transformation experiments with a selection for tetracycline-resistant colonies (that is, for cells containing pRKl). A total of forty-two tetracycline-resistant colonies were isolated, thirty of which contained circular pRK1 molecules identical to those originally injected. The remaining twelve colonies contained unique plasmids that were grouped into five different classes of recombinant molecules. All five of these unique recombinant classes appear to contain a common deletion endpoint occurring at a specific region of the pBR322 segment of pRKl. Four of the unique recombinant classes appear to have arisen from the deletion of a segment of a pRKl trimer or dimer molecule, while the fifth class appears to have resulted from recombination between pRKl and pXl followed by a deletion event within this recombinant. It is uncertain whether these deletions are occurring within the eukaryotic cell or upon subsequent transformation of the bacterial cell. If the latter, then the passage of the plasmid DNA through the eukaryotic cell alters a specific site of the pBR322 DNA in such a way that deletions can occur at a high frequency in this region when the plasmid DNA is introduced back into a bacterial cell. Thus, we have established a prokaryote-eukaryote-prokaryote DNA transfer and recovery system which should be useful in studies on DNA replication and the regulation of gene expression in higher eukaryotes.     

Chemical and Physical Characterization of Interfacial-Active Lipids from Rhodococcus erythropolis Grown on n-Alkanes

Lipophilic compounds of the culture suspension containing Rhodococcus erythropolis DSM43215 had surfactant properties when the bacteria were cultivated with n-alkanes as the sole carbon source. Thirteen main components from a dichloromethane-methanol extract of the R. erythropolis cultures were isolated and characterized to specify quantitatively their surfactant properties, e.g., minimum surface and interfacial tensions and critical micelle concentrations. The interfacial activity of the organic extract was dominated by α,α-trehalose-6,6′-dicorynomycolates which reduced interfacial tension from 44 to 18 mN/m. Phosphatidylethanolamines which were also present in the organic extract reduced the interfacial tension below 1 mN/m. The trehalose corynomycolates had extremely low critical micelle concentrations in high-salinity solutions, and the interfacial properties were stabile in solutions with a wide range of pH and ionic strength.     

Anticataleptic potencies of glutamate-antagonists

Summary The anticataleptic effects of non-competitive and competitive NMDA antagonists as well as those of an agonist at the allosteric glycine binding site of the NMDA receptor were tested in the catalepsy model. Some of these drugs were further tested in a reaction time task demanding rapid locomotor initiation. The results show that the non-competitive NMDA antagonists dizocilpine and memantine as well as the competitive antagonists CGP 39551, CGP 37849 and CPPene antagonized dopamine D2 receptor mediated catalepsy induced by haloperidol. D-cycloserine, a partial glycine agonist per se had no effects, but it enhanced the anticataleptic effects of dizocilpine when coadministered. However, the effects of CGP 37849 were abolished. Dopamine D1 receptor mediated catalepsy induced by SCH 23390 was antagonized by dizocilpine, memantine, CPPene, but not by CGP 37849. In the reaction time task dizocilpine, memantine and CGP 37849 were tested for their anti-akinetic and anti-bradykinetic potencies. All these compounds improved haloperidolinduced slowing of reaction time. However, they acted differentially on haloperidol-induced slowing of movement execution and decreased initial acceleration. Thus, antagonists at the NMDA receptor may have a therapeutic potential in the treatment of Parkinson's disease. Their potency can be manipulated specifically at the glycine binding site.     

Escherichia coli delta 1-pyrroline-5-carboxylate reductase: gene sequence, protein overproduction and purification.

The sequence of the Escherichia coli proC gene which encodes for delta 1-pyrroline-5-carboxylate (PCA) reductase was determined. Overproduction of the proC gene product via an expression plasmid carrying the bacteriophage lambda PL promoter allowed the purification to homogeneity of PCA reductase by affinity adsorption chromatography. NH2 and COOH-terminal analysis and amino acid composition of the purified proC protein is consistent with the gene sequence reported. The molecular weight of the proC monomer is 28,112.