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Recently, ISHIYAMA and TAKATSU 1 suceeded in converting saline agglutinating anti-A from the albumin gland of the snail Helix pomatia into "incomplete", non-agglutinating anti-A by reductive cleavage and subsequent alkylation according to PORTER 2. However it is known 3, that this antibody-like anti-A is not only directed against the non-reducing terminal a-linked iV-Acetyl-D-galactosamine (GalNAc) of blood group A substance and other glycoproteins 4, but also reacts with the terminal yS-anomer of GalNAc, although the affinity is much greater to the a-glycosidically bound hexosamine 3' 4. It was therefore of interest, to investigate the reaction of this "incomplete" anti-A with human 0 or B red blood cells (rbc), which had been treated with neuraminidase (RDE) and, as a consequence, had developed terminal /Minked GalNAc in their superficial glycoprotein layer, thus rendering them agglutinable by the normal snail agglutinin too. As these new uncovered receptors, which can be partly removed by proteolytic enzymes, are located in the outermost relief structure of the rbc membrane — whereas the blood group A specific antigens are exposed more in the deeper clefts or valleys of the surface architecture — we expected, that the "incomplete" snail agglutinin, while not agglutinating A erythrocytes, would still react with RDE-treated 0 and B rbc and also agglutinate other rbc (pigeon, dude, chicken horse) known to show superficial glycoprotein bound /Minked GalNAc after enzymatic removal of neuraminic acid. In confirming our view5, that the question of "incomplete" agglutinins is also a membrane problem, we found (Table I), that A rbc treated with pronase were agglutinated directly in saline by the "incomplete" anti-A, or, without treatment, were clumped by an immune serum to the heterophile snail anti-A, blocking the A receptors. In addition, A rbc "incompletely" coated with snail anti-A and subsequently incubated with blood group A substance (peptone) were not agglutinated by the immune serum to the snail agglutinin anymore, demonstrating the presence of free
It is shown that the 1700 x g supernatant of human lymphocytes stimulated with phytohaemagglutinin had an inhibitory, but not a lytic, effect on the permanent tissue sulture cell strain of Fl-cells. The factor called proliferation inhibition factor seems to be a protein. The incorporation of H3-thymidin into DNA was affected more and earlier than the incorporation of H3-uridin into RNA or C14-Leucin into protein of the cultured cells. There was no effect on respiration or glycolysis.
The changes in the content of protein-bound SH (PSH) and nonprotein SH (NPSH) were determined during the development of DEN-rat hepatoma. The observed increase of NPSH is understood as a general phenomenon of chemically induced carcinogenesis. The SH-content of the soluble cell proteins (PSH) was significantly higher in the established tumor than in the normal liver. Furthermore, NPSH and PSH were determined after incubation of liver slices in 4-hydroxypentenal (ΗΡΕ). The NPSH of the normal liver as well as of the established hepatoma decreased by 50 percent. The PSH were much more resistant against ΗΡΕ decreasing only in the earlier stages of tumor development by 14%/g wet weight. No significant decrease in PSH/mg protein was observed. Similarly, the influence of ΗΡΕ on oxygen uptake of the normal liver and the hepatoma was determined: with normal liver no influence was observed, whereas a significant inhibition of 10% occurred only in the established tumor. These weak cytotoxic effects of ΗΡΕ on the DEN-hepatoma is related to the low malignancy of this tumor.
The stromata of etioplasts, greening etioplasts, and chloroplasts contain proteins which crossreact with proteins of the lamellar system of chloroplasts. It is shown that at least one cross-reacting protein is a water-soluble precursor of the lamellar system. The water-insoluble fractions of the plastids were dissolved in buffer containing Na-benzene-dodecylsulfonate and analyzed by gel electrophoresis. The disc electrophoresis patterns of the prolamellar bodies of etioplasts showed 8 protein-containing bands of which 7 were also present in the preparations from greening etioplasts. The latter also yielded 5 new protein-containing bands. The lamellar system of chloroplasts showed only 8 bands which were identical with those of greening etioplasts, but it had only 3 bands in common with the prolamellar bodies of the etioplasts. Two of these proteins may be identical with antigens cross-reacting with stroma proteins.
One of the earliest consequences of slicing plant storage organs such as potato tubers into thin disks is the formation of polysomes, which in potato slices is complete after 9 hours and is dependent on transcription. Fresh disks do not incorporate 32P, 3H-uridine or 14C-leucine into their ribosomes, whereas ribosomes and polysomes of aged disks use these precursors effectively. This development can be completely blocked by actinomycin D. Among the different RNAs synthesized during aging is 28S- and 16S—rRNA, 5S—RNA, tRNA, and a component sedimenting around 15—18S with a base-composition different from 16S—rRNA, 5S- and 4S—RNA and which supports peptide formation in an in vitro incorporation system. It is suggested that this compound represents mRNA, which is not available immediately after slicing the tissue. These findings are consistent with the view of a derepression phenomenon in sliced storage tissue.
The hypothesis of cancerostatic activity of deoxycholic acid, recently outlined, is supported by correlation of natural cancer resistance with the level of deoxycholic acid in animals and humans. Analyses of sera indicate lower levels of unconjugated deoxycholic acid in cancer patients, the mean values of other bile acids being normal. Application of this theory to statistics of cancer incidence reveals possibilities of new aspects.
By immunisation of rabbits with stroma-freed chloroplasts and other preparations of the lamellar system, antibodies to phosphatidyl glycerol were formed. By injection of phosphatidyl glycerol, bound to methylated bovine serum albumin, the rabbits also reacted with the formation of antibodies to this phosphatide. The antiserum to phosphatidyl glycerol yielded no reactions with phosphatidyl choline and the glycolipids sulphoquinovosyl diglyceride and mono- and digalactosyl diglyceride, which are present in chloroplasts. Stroma-freed chloroplasts from Antirrhinum majus and Nicotiana tabacum were not agglutinated by antisera to phosphatidyl glycerol. By means of the Coombs test, the “mixed-antigen-agglutination” and sateration experiments it was possible to demonstrate that antibodies to phosphatidyl glycerol are specifically adsorbed onto stroma-freed chloroplasts. After partial protein decomposition by proteases, stroma-freed chloroplasts were agglutinated. Fragments of the thylakoid membranes (ultrasonic supernatant) were precipitated only after partial protein decomposition and functioned in the Coombs test just like stroma-freed chloroplasts. However, fragments of the lamellar system (ultrasonic sediment) were directly agglutinated. Isolated chloroplasts in tris buffer-sucrose solution and in tris buffer-sodium chloride solution were equally agglutinated by antiserum to phosphatidyl glycerol. From the experiments it is concluded that the antigen determinants of the phosphatidyl glycerol are located on the antibody-accessible surface of the thylakoids. The agglutination of stroma-freed chloroplasts was, however, sterically hindered by membrane proteins. In those cases in which chloroplast preparations were directly agglutinated, it is assumed that either thylakoids were disrupted or that they were swollen, resulting in a change in the protein layer of the membranes in such a way that no steric hindrance occurs.
Article Notizen: Reproduktive Leistung weiblicher Mäuse nach Blockierung der DNS-Synthese / Reproductive Capacity of Female Mice after Inhibition of DNA Synthesis was published on February 1, 1971 in the journal Zeitschrift für Naturforschung B (volume 26, issue 2).
