Regulation of polyamine biosynthesis by antizyme and some recent developments relating the induction of polyamine biosynthesis to cell growth

This review considers the role of antizyme, of amino acids and of protein synthesis in the regulation of polyamine biosynthesis.The ornithine decarboxylase of eukaryotic ceils and ofEscherichia coli coli can be non-competitively inhibited by proteins, termed antizymes, which are induced by di-and poly- amines. Some antizymes have been purified to homogeneity and have been shown to be structurally unique to the cell of origin. Yet, the E. c o l i antizyme and the rat liver antizyme cross react and inhibit each other's biosynthetic decarboxylases. These results indicate that aspects of the control of polyamine biosynthesis have been highly conserved throughout evolution.Evidence for the physiological role of the antizyme in mammalian cells rests upon its identification in normal uninduced cells, upon the inverse relationship that exists between antizyme and ornithine decarboxylase as well as upon the existence of the complex of ornithine decarboxylase and antizyme in vivo. Furthermore, the antizyme has been shown to be highly specific; its Keq for ornithine decarboxylase is 1.4 x 1011 M-1. In addition, mammalian ceils contain an anti-antizyme, a protein that specifically binds to the antizyme of an ornithine decarboxylase-antizyme complex and liberates free ornithine decarboxylase from the complex. In B. coli , in which polyamine biosynthesis is mediated both by ornithine decarboxylase and by arginine decarboxylase, three proteins (one acidic and two basic) have been purified, each of which inhibits both these enzymes. They do not inhibit the biodegradative ornithine and arginine decarboxylases nor lysine decarboxylase. The two basic inhibitors have been shown to correspond to the ribosomal proteins S₂₀/L₂₆ and L₃₄, respectively. The relationship of the acidic antizyme to other known B. coli proteins remains to be determined.     

The distribution and interconversion of ammonium and nitrate in the Skallingen salt marsh (Denmark) and their exchange with the adjacent coastal water

The potential nitrogen sources for the primary production in the intertidal area are nitrogen compounds obtained from mineralization in the sediment and the water column, nitrogen fixation, outflow from rivers and groundwater seeping from the mainland. The available inorganic nitrogen in the adjacent coastal waters decreases from 50–80 μmol NO₃ ^-/l and 6–15 μmol NH₄ ⁺/l in early spring to ca one tenth during the growing season. In the sediment of the tidal flats available ammonia and nitrate vary between 50 and 100 μmol/1 pw. In the salt marsh available ammonia increases from 200–300 nmol NH₄ ⁺/g fwt to approximately double the amount, and the available nitrate varies from 100–300 nmol NO₃ ^-/g fwt (250–750 μmol NO₃ ^-/l pw) to ca one third during the growing season. The exchange of NH₄ ⁺, NO₂ ^- and NO₃ ^- across the sediment water interface has been estimated during tidal cycles under light and dark conditions on the tidal flats. The flux of nitrogen was dependent on the flora and fauna as well as the time of the year. The tidal activity, frequency and length of inundation are considered the driving force in a two-way process between salt marshes and adjacent coastal waters. The role of marsh sediment, tidal water and sediments of the tidal flats as sites of accumulation, consumption and remineralization of organic matter is emphasized. The possible exchange of ammonia and nitrate between the salt marsh and the different compartments of the tidal water is discussed.     

The nucleotide sequence of tobacco rattle virus RNA-2 (CAM strain).

The nucleotide sequence of the smaller genomic strand (RNA-2) of the bipartite tobacco rattle virus (CAM strain) has been determined. RNA-2 is capped at the 5' terminus and contains 1799 nucleotide residues. There is a single 223 codon long open reading frame extending from nucleotide 574 to 1242 which designates a protein of Mr 23,654. The derived amino acid composition, in percent, matches that previously determined for the virus capsid protein. The long open reading frame is flanked by 5' and 3' untranslated regions of 573 and 554 nucleotides, respectively. The 5' leader sequence contains two different sets of direct repeats, one of 119 nucleotides and the other of 76. It also contains 13 apparently unused AUG codons, four of which lie in the same frame as the capsid protein cistron. The 3' terminal sequence of RNA-2 is identical to that of the larger genomic strand (RNA-1) for 459 nucleotides.     

On the mechanism of activation of the ATP X Mg(II)-dependent phosphoprotein phosphatase by kinase FA

The mechanism of activation of the Mg(II) X ATP-dependent phosphatase by the kinase FA has been investigated. The inactive protein phosphatase can be represented as FC X M where FC is the inactive catalytic component and M is the heat-stable modulator protein (also known as inhibitor-2). Phosphorylation of the modulator protein is demonstrated during activation of FC X M. In addition, continuous ATP hydrolysis during the activation is observed. This suggests that a cyclic phosphorylation-dephosphorylation reaction is continuously occurring during the activation. It is proposed that phosphorylation of the modulator protein causes an isomerization in FC to generate an active phosphatase. The activated phosphatase is capable of dephosphorylating the phosphorylated modulator. Upon dephosphorylation of modulator, the active phosphatase returns to its inactive form via a slow isomerization.     

Nucleotide sequence of v-fps in the PRCII strain of avian sarcoma virus.

PRCII is an avian retrovirus whose oncogene (v-fps) induces fibrosarcomas in birds. The viral gene v-fps arose by transduction of an undetermined portion of a cellular gene known as c-fps. PRCII is weakly oncogenic when compared with Fujinami sarcoma virus, another transforming virus containing v-fps. As a first step in the elucidation of the molecular basis for the decreased virulence of PRCII, we have determined the entire nucleotide sequence of v-fps in the PRCII genome. The v-fps domain in PRCII encodes a polypeptide with a molecular weight of ca. 60,500 fused to a portion of the polyprotein encoded by the viral structural gene gag. The hybrid gag-fps polyprotein of PRCII would have a molecular weight of ca. 98,100, in accord with results of previous studies of the protein encoded by the PRCII genome. The leftward junctions between fps and gag in Fujinami sarcoma virus and PRCII are located at the same position in fps, but at different positions in gag. A sequence of 1,020 nucleotides, bounded by direct repeats of 6 nucleotides, is present in v-fps of Fujinami sarcoma virus but absent from PRCII. Our data should permit further explorations of the relationship between structure and function in the transforming protein encoded by v-fps.     

管花马兜铃化学成分的研究

从管花马兜铃中分得马兜铃酸-A,7-甲氧基马兜铃酸-A,马兜铃内酰胺-β-D-葡萄糖甙,尿囊素和Eupomatenoid-7。     

Extractive bioconversion in aqueous two-phase systems

Summary The transformation of hydrocortisone to prednisolone was studied in aqueous two-phase systems, as a model for the extractive bioconversion of fine chemicals. The bacterium, Arthrobacter simplex, was able to grow in the two-phase system and the cells could be revitalized after a period of use. Use of aqueous two-phase systems made it possible to operate the reaction at higher substrate concentrations than in pure buffer solution. An adsorptive method to remove the product from the top phase was tested and shown to be both efficient and compatible with the overall process. In order to reduce the costs of operation in aqueous two-phase systems, a cheaper starch-based polymer, Reppal-PES, was successfully used as a substitute for dextran.Dedicated to Professor Dr. Georg Manecke on the occasion of his 70th birthday     

二十三种药用种子(或果实)中油的化学组成

本文报道了二十三种药用种子(或果实)的含油率和油的化学组成成分,它们分属于二十个科二十二个属中。本文所发表的大部分资料尚未见国内外文献的报道。     

Chemotactic activity of platelet alpha granule proteins for fibroblasts

At sites of blood vessel injury, platelets release numerous substances that may have biological activities influencing cellular responses. In this study we examined separately the chemotactic activity for fibroblasts of three highly purified proteins obtained from platelet alpha granules: platelet factor 4 (PF4), platelet-derived growth factor (PDGF), and beta-thromboglobulin (BTG). We observed that each of these proteins was strongly chemotactic for fibroblasts, with maximum chemotactic activity in each instance comparable to that observed with an optimal concentration of the control chemotactic protein, plasma fibronectin. Each protein was active at very low concentrations. The peak chemotactic activities of PF4, PDGF, and BTG occurred at 200 mg/ml, 30 ng/ml, and 6 ng/ml, respectively. Specificity of fibroblast chemotaxis to individual platelet proteins was provided by finding that anti-PF4 immunoglobulin blocked the chemotactic activity of PF4 without affecting the chemotactic activity of PDGF, while anti-PDGF immunoglobulin blocked the activity of PDGF but did not alter the capacity of PF4 to promote fibroblast chemotaxis. These results suggest that in vivo several alpha granule proteins released from platelets may affect wound healing by causing directed fibroblast migration.     

Genetic characterization of mouse immunoglobulin allotypic determinants (allotopes) defined by monoclonal antibodies

We have generated a new series of monoclonal antibodies recognizing allotypic determinants on mouse IgG₁, IgG_2a, and IgG_2b. In this communication we describe their reactivities with immunoglobulins of the inbred mouse strains. Comparison with serology charts indicates that many of these monoclonal antibodies detect allotypic specificities previously defined by conventional antisera; others define previously undescribed specificities. Strain and isotype distribution allows us to assign five new allotypic specificities to Igh-1 and three new specificities to Igh-3. In addition, on the basis of reactivity with the monoclonal antibodies, we have defined a new Igh haplotype in SWR/J mice, Igh ^p.Abbreviations used in this paper Igh immunoglobulin heavy chain - SDS sodium dodecyl sulfate