Broad-Host-Range Agrocin of Agrobacterium tumefaciens

Eighteen strains of Agrobacterium tumefaciens isolated from crown galls were tested for agrocin production. Of six agrocin-producing strains, one (D286) produced a broad-host-range agrocin active against strains carrying nopaline, octopine, and agropine type Ti plasmids. Sensitivity to agrocin D286 was found to map in the 11- to 18-megadalton region of the nopaline Ti plasmid pTiC58. The agrocin was partially purified, and its physical characteristics were consistent with its being a nucleotide, as is agrocin 84. Agrocin D286 was shown to inhibit DNA, RNA, and protein syntheses. Strain D286 spontaneously lost its pathogenicity, and its potential for use in the biological control of crown gall is discussed.     

Studies on lung surfactant replacement in respiratory distress syndrome. Rapid film formation from binary mixed liposomes

Binary mixed liposomes were prepared from dipalmitoylphosphatidylcholine (DPPC) and a minor compound, e.g., egg phosphatidylglycerol (PG) at a ratio of 9:1. Using different preparative techniques, large unilamellar vesicles (LUV), small unilamellar vesicles (SUV) or multilamellar vesicles (MLV) were obtained and were studied with an electron microscope for morphology, with a Wilhelmy balance for spreading and surface tension lowering potential, and in the surfactant-depleted isolated rat lung for their ability to restore expiratory lung capacity. Only the simultaneous investigation of phospholipids by negative staining and thin sectioning allows unequivocal classification of liposomes. The surface-active structures prepared with the technique of Bangham et al. (Bangham, A.D., Hill, M.W. and Miller, N.G.A. (1974) in Methods in Membrane Biology (Korn, E., ed.), Vol. 1, pp. 1-68, Plenum Press, New York) at room temperature are LUV. LUV containing DPPC:PG at a ratio of 9:1 rapidly spread to a film with high surface tension lowering potential. Within 5 min after injection into the subphase they rise to the surface and form a film at the air/liquid interface able to lower the surface tension to less than 1 mN/m at compression. SUV of the same chemical composition, however, are immediately surface-active only when spread directly onto the surface. MLV exhibit poor surface activity. LUV or pure DPPC, applied onto the surface, are weakly surface active within 5 min. DPPC vesicles injected into the subphase at 37 degrees C do not adsorb to any film with surface tension lowering potential in this time. The minor compounds PE, PI, PS, PA, lysoPC enable DPPC to form surface-active films after application on saline at 37 degrees C. Removal of surfactant decreases the expiratory lung capacity of the isolated rat lung from 49.7 to 12.4% at 4 cmH2O. After substitution with natural surfactant, the expiratory lung capacity is twice that of the washed lung (25.9%), but the original distensibility of the native lung is not restituted. The effect of LUV containing DPPC:PG at a ratio of 9:1 is also remarkable (21.2%).     

Isolation and characterization of an inter-alpha-trypsin inhibitor-IgG complex from human serum

Inter-alpha-trypsin inhibitor is a human serum protease inhibitor of Mr 180 000 which may release physiological derivatives. A complex between IgG and an inter-alpha-trypsin inhibitor derivative of Mr 30 000 has been recently detected in human serum and was found to be inactive against trypsin, in contrast with the known inhibitory activity of the free 30-kDa derivative. The present study deals with detailed characterization of an inter-alpha-trypsin inhibitor-IgG complex following its purification by affinity chromatography techniques (anti-inter-alpha-trypsin inhibitor immunoadsorbent and Protein A-Sepharose) in mild conditions. The resulting product reacted simultaneously with anti-IgG and anti-inter-alpha-trypsin inhibitor antibodies. This complex contained Mr 180 000 inhibitor at least to some extent. It migrated in the beta-gamma zone in agarose; its molecular weight was estimated to be 1 500 000 or more; part of it displayed covalent bonding between inter-alpha-trypsin inhibitor and IgG; it had a trypsin inhibitor activity. Immunoelectrophoresis allowed one to demonstrate the native complex in serum owing to the use of anti-inter-alpha-trypsin inhibitor and anti-gamma radioactively labelled antibodies. The double immunoreactivity thus evidenced proved to be heterogeneous with respect to its level and location in the native as well as in the purified complex.     

Activity of organophosphorus insecticides in bacterial tests for mutagenicity and DNA repair--direct alkylation versus metabolic activation and breakdown. II. O,O-dimethyl-O-(1,2-dibromo-2,2-dichloroethyl)-phosphate and two O-ether derivatives of trichlorfon

The following organophosphates were tested for their ability to induce DNA damage in a rec-type repair test with Proteus mirabilis strains PG713 (rec- hcr-) and PG273 (wild-type) and point mutations in the his- strain TA100 of Salmonella typhimurium: O,O-dimethyl-O-(1,2-dibromo-2,2-dichloroethyl)-phosphate (NALED); trichlorfon-O-methyl ether (TCP-O-ME), O,O-dimethyl-(1-methoxy-2,2,2-trichlorethyl)-phosphonate; trichlorfon-O-methyl ether vinyl derivative (TCP-O-MEVD), O,O-dimethyl-(1-methoxy-2,2-dichlorovinyl)-phosphonate. All compounds were negative in the repair test but induced base pair substitutions in S. typhimurium. The mutagenicity of NALED is due to the direct alkylating ability of the parental molecule and to mutagenic metabolites generated by enzymatic splitting of the side chain. Glutathion-dependent enzymes in the S9-mix eliminate the mutagenic activity of NALED completely. Mutation induction by TCP-O-ME and TCP-O-MEVD is predominantly caused by the reactive O-methyl ether configuration of the side chain and is resistant to metabolic inactivation by NADPH- or glutathion-dependent enzymatic pathways in the S9-mix of mice.     

Combined application of misonidazole and piotron pions on mouse embryos

Mouse embryos on day 8 of gestation were irradiated with negative pions (12.5-100 rad) or 200 kV X-rays (12.5-150 rad). Misonidazole (MISO), a hypoxic cell radiosensitizer, was applied 30 min before exposure. On day 13 the fetuses were examined for lethality, growth retardation and malformation. No significant embryolethal effects were observed after irradiation alone in the dose range of 12.5-100 rad (X-rays or pions). However, MISO alone and in combination with radiation led to high rates of lethality. The frequency of growth retardation was significantly increased at 100 rad and in combined treatments at low radiation doses. MISO and irradiation with 50 rad and more induced complex damages consisting of multiple and severe malformations and growth retardation. The relative biological effectiveness (RBE) for teratogenic effects was 1.6. In conclusion, the combined application of MISO and radiation of different LET revealed a strong enhancing action compared to single treatments. The extent of enhancement depends on both radiation quality and dose.     

Steroid metabolism in primates. XV. Excretion of C19 and C21 steroids in the urine of baboons (Papio hamadryas) after long-term treatment with a combination of mestranol-chlormadinone acetate

The urinary excretion of C21- and C19-steroids was investigated in female babons (Papio hamadryas) treated with the ovulation inhibitor Ovosiston (mestranol + chlormadinone-acetate), in comparison with an untreated control Group Urinary C21-steroid excretion was not significantly altered by Ovosiston. 17-Ketosteroids were decreased, predominantly 11-oxygenated compounds.     

Das Vorkommen von Malatenzym und Malo-Lactat-Enzym bei verschiedenen Milchsäurebakterien

1. Malic enzyme was induced by malic acid and malo-lactic enzyme was induced by malic acid and glucose in cells of three strains ofLactobacillus casei that were able to grow on malate as carbon source. Two strains ofStreptococcus faecalis formed malic enzyme only, whereas only malo-lactic enzyme was formed by a glucose requiring strain ofStreptococcus lactis.
2. Given sequential induction, cells ofLactobacillus casei M40 were found to contain malic enzyme and malo-lactic enzyme simultaneously.
3. Malic enzyme and malo-lactic enzyme have been separated by chromatography on Sephadex G-200. These two enzymes have a different pH optimum, different affinities for substrates, form different end products from malate, and have molecular weights of 120000 and 150000 daltons respectively.

     

The inhibition of nucleic acid synthesis by mycophenolic acid

1. Mycophenolic acid, an antibiotic of some antiquity that more recently has been found to have marked activity against a range of tumours in mice and rats, strongly inhibits DNA synthesis in the L strain of fibroblasts in vitro. 2. The extent of the inhibition of DNA synthesis is markedly increased by preincubation of the cells with mycophenolic acid before the addition of [(14)C]thymidine. 3. The inhibition of DNA synthesis by mycophenolic acid in L cells in vitro is reversed by guanine in a non-competitive manner, but not by hypoxanthine, xanthine or adenine. 4. The reversal of inhibition by guanine can be suppressed by hypoxanthine, 6-mercaptopurine and adenine. 5. Mycophenolic acid does not inhibit the incorporation of [(14)C]thymidine into DNA in suspensions of Landschütz and Yoshida ascites cells in vitro. 6. Mycophenolic acid inhibits the conversion of [(14)C]hypoxanthine into cold-acid-soluble and -insoluble guanine nucleotides in Landschütz and Yoshida ascites cells and also in L cells in vitro. There is some increase in the radioactivity of the adenine fraction in the presence of the antibiotic. 7. Mycophenolic acid inhibits the conversion of [(14)C]hypoxanthine into xanthine and guanine fractions in a cell-free system from Landschütz cells capable of converting hypoxanthine into IMP, XMP and GMP. 8. Preparations of IMP dehydrogenase from Landschütz ascites cells, calf thymus and LS cells are strongly inhibited by mycophenolic acid. The inhibition showed mixed type kinetics with K(i) values of between 3.03x10(-8) and 4.5x10(-8)m. 9. Evidence was also obtained for a partial, possibly indirect, inhibition by mycophenolic acid of an early stage of biosynthesis of purine nucleotides as indicated by a decrease in the accumulation of formylglycine amide ribonucleotide induced by the antibiotic azaserine in suspensions of Landschütz and Yoshida ascites cells and L cells in vitro.     

Elektronenmikroskopische Zytomorphologie der männlichen Brustdrüse

Zusammenfassung Im Vergleich zu lichtmikroskopischen Untersuchungen an der Mamma virilis wird anhand von 2 operativ entfernten Brustdrüsen eines 57 und 63 Jahre alten Mannes die elektronenmikroskopisch erfaßbare Zytomorphologie beschrieben. Die Befunde werden den physiologischen Wachstumsimpulsen dieses Organs gegenübergestellt und Fragen der Zelldifferenzierung, der Desquamation und apokrinen Sekretion beantwortet. Elektronenmikroskopisch werden am Drüsenepithel Basalzellen, größere Zellen der oberflächlichen Zellreihen und Myoepithelzellen unterschieden. Diese Zellen entsprechen den Gangepithelien der weiblichen Brustdrüse und besitzen intracytoplasmatische Filamente. Diese stellen ein häufiges Differenzierungsprodukt des Zytoplasmas dar. Mechanismen einer Sekretion waren nicht nachweisbar. In die Drüsenlichtung werden pseudopodienartig vorgewölbte Zytoplasmateile abgeschnürt (Extrasionsvorgang). — Superfiziale Zellen werden desquamiert, wobei die Zytolyse in den marginalen Zytoplasmaschichten erfolgt. Kern und Teile des Zytoplasmas gelangen in die Drüsenlichtung. — Die Befunde zeigen die von Lebensalter und Proliferationsreiz abhängigen Vorgänge eines permanenten Zellersatzes in der männlichen Brustdrüse an.

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Ultrastructure of the mammary gland of the human male

Summary The ultrastructure of two mammary glands obtained operatively from a 57-year old and a 63-year old man was compared to the structure observed in the light microscope, and related to stimuli controlling growth of the gland, cellular differentiation and desquamation, and apocrine secretion. The glandular epithelium, which is analogous to that of the female mammary gland, is differentiated into basic cells, large superficial cells, and myoepithelial cells. The cells have intracytoplasmic filaments, that may be a sign of differentiation. Mechanisms for secretion were not observed, although pseudopodia-like parts of the cytoplasm are extruded into the glandular lumen. Superficial cells are desquamated, followed by cytolysis of their margins. These findings illustrate the replacement of cells due to age and altered stimuli.

Frl. St. Walter, lt. Assistentin des elektronenmikroskopischen Labors, danken wir für Präparationen und Photoarbeiten.