Polyamine als Stimulatoren von Genaktivitäten Eine autoradiographische Studie an Riesenchromosomen von Chironomus thummi

Zusammenfassung Inaktive Riesenchromosomen der Speicheldrüsen ausgewachsener Chironomus thummi-Larven zeigten nach 60 min Inkubation mit 0,05 N Putrescin-, Spermidin-oder Spermin-Lösung erneute Syntheseaktivitäten, die sich im Einbau von radioaktiv markiertem Uridin autoradiographisch zu erkennen geben. Diese Beobachtung wird im Zusammenhang mit der bekannten genaktivierenden Wirkung von Mg⁺⁺ diskutiert. Auf der Basis zahlreicher biochemisch analoger Wirkungen von Polyaminen und Mg⁺⁺ wird ein ursprünglich für die genaktivierende Wirkung von Mg⁺⁺ postuliertes Modell auf Polyamine übertragen.

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Stimulation of gene activities by polyamines an autoradiographic study with giant chromosomes of Chironomus thummi

Summary Inactive salivary gland giant chromosomes of full grown Chironomus thummi larvae showed after 60 min of incubation in 0.05 N putrescine, spermidine or spermine solutions autoradiographically demonstrable incorporation of radioactiv labelled uridine caused by a reactivation of RNA synthesis. This observations is discussed in relation to the known gene activating effect of Mg⁺⁺, and, since polyamines and Mg⁺⁺ have numerous effects in common, it is suggested that polyamines affect gene activity in a way similar to Mg⁺⁺.

     

Formation of hybrid anthranilate synthetase in vitro from components of Aspergillus and Neurospora

Glutamine-dependent anthranilate synthetase was produced in vitro by mixing the extracts of a trypA and a trypC mutant of Aspergillus nidulans. Neither mutant alone possessed this activity. The enzyme formed in the mixture had the properties of the wild-type anthranilate synthetase which, together with N-(5-phosphoribosyl) anthranilate (PRA) isomerase and indole 3-glycerol phosphate (InGP) synthetase, is found in a 10S multienzyme complex. Extracts of the trypA69 mutant contained a 6.5S protein as the active component—presumably the trypC ⁺ product—which in addition showed PRA isomerase and InGP synthetase activity. Extracts of the trypC801 mutant lacked all three enzyme activities but contained a 4.5S component—the trypA ⁺ gene product—which in vitro showed ammonia-dependent anthranilate synthetase activity. These mutants are analogous in their properties to certain tryp-2 and tryp-1 mutants of Neurospora. When complementary extracts of the two genera were mixed (Aspergillus trypA with Neurospora tryp-1 or Aspergillus trypC with Neurospora tryp-2), a hybrid glutamine-dependent anthranilate synthetase was obtained which showed less than half the activity produced in homologous combinations.This study was supported by Grant GB 22655 from the National Science Foundation to J.A.DeM.     

Morphologic der seeigelzähne II. Die gekielten Zähne der echinacea (Echinodermata,echinoidea)

Structure and growth of a keeled tooth are discussed with Paracentrotus lividus as the main example. The microscopic structure of the tooth skeletons of other sea urchins was compared, considering at least one member of each family with the exception of Saleniidae. Attention is called to the necessary revision of the system of sea urchins.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Bone Marrow Graft in Man after Conditioning by Antilymphocytic Serum

Allogeneic bone marrow grafts carried out after previous administration of antilymphocytic serum alone were attempted in 16 patients. Of these, six had acute myeloblastic leukaemia, four acute lymphoblastic leukaemia, and one a blast cell crisis in polycythaemia vera. Ten of these patients were in an overt phase of the disease and resistant to chemotherapy, while nine had complete agranulocytosis. In five of these patients erythrocyte and leucocyte antigenic markers demonstrated the establishment of the graft. One patient had thalassaemia major, and four others had aplasia of the bone marrow, in one case due to chloramphenicol poisoning and in another to virus hepatitis. The grafts were successful in the last two patients and transformed their clinical condition.No signs of early acute secondary disease were noted in any of the patients, either when the donor had been given antilymphocytic serum or when he was untreated. The grafts had no adoptive immunotherapeutic effect on the acute leukaemia. These observations have clearly shown that antilymphocytic serum has an immunosuppressive effect in man when it is used alone.     

Ueber den stand der Agrarmeteorologischen Forschung in der Deutschen Demokratischen Republik

Ohne Zusammenfassung     

Elektronenmikroskopische Untersuchungen über Glaskörperrindenzellen und Zonulafasern

Zusammenfassung Es werden folgende Befunde zur Feinstruktur des Glaskörpers beim 16 Tage alten Rattenembryo und der Glaskörperrinde beiderseits der Ora serrata beim 3 Jahre alten, an Retinoblastom erkrankten Kind mitgeteilt:Der Glaskörper des Rattenembryos und die Glaskörperrinde des kindlichen Auges enthalten Fibroblasten. Sie unterscheiden sich nicht von den im Bindegewebe vorkommenden Fibroblasten. Im embryonalen Rattenglaskörper wurden außerdem faserbildende Zellen mit wabiger Struktur des Zytoplasmas beobachtet.Die Fibroblasten der Glaskörperrinde bilden die Fibrillen des Glaskörpergerüstes und der Zonulafasern. Diese Fibrillen zeigen eine deutliche Querstreifung. Die Streifung ist unregelmäßig oder periodisch. Die Länge der Perioden beträgt in unseren Schnitten bei den Glaskörperfibrillen des Rattenembryos und des kindlichen Auges meist etwa 120, seltener 210 A. An den Fibrillenbündeln einer Zonulafaser des kindlichen Auges wurden Perioden von 90–120, 400, 440 und 630 A beobachtet.Die Fibroblasten der Glaskörperrinde des kindlichen Auges liegen im Bereich der Pars plana corporis ciliaris auch tief in den Buchten und Falten des Ciliarepithels. Hierdurch wird eine maximal große Anheftungsfläche für die von ihnen produzierten Fibrillen der Zonulafasern gewährleistet.Die Pars plana corporis ciliaris des kindlichen Auges ist von einem dichten Netz von Fibroblastenfortsätzen überzogen. Auch vereinzelte Makrophagen finden sich hier.Unsere elektronenmikroskopischen Befunde bestätigen die Angaben von Balazs über das Vorkommen von Fibrocyten (Fibroblasten) und Makrophagen in der Glaskörperrinde. Ferner bestätigen sie die bereits von früheren Autoren lichtmikroskopisch gewonnenen Erkenntnisse, wonach es sich beim Glaskörper um mesenchymales Gewebe, bei den Zonulafasern im Bindegewebsfasern handelt.

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Summary The following electron microscopical findings in the vitreous body of 16-day-old rat embryos and in the vitreoretinal border layer on both sides of the ora serrata in a 3-year-old child are reported:The vitreous body of the rat embryo and the vitreoretinal border layer of the infant eye contain fibroblasts. These fibroblasts do not differ from those present in connective tissue. The embryonic vitreous body of the rat contains fibre-forming cells, which show an alveolar structure of the cytoplasm.The fibroblasts in the cortical tissue layer of the vitreous body form the fibrils of the stroma of the vitreous body and the zonula fibres. These fibrils show a marked cross striation. The striation is either irregular or shows periodicity. In the vitreous body of the rat embryo and of the infant eye the lenght of these periods has been measured with 120 and 210 A. Periods of 90–120, 400, 440 and 630 A could be shown in the fibrillar bundles of a zonula fibre of the infant eye. In the region of the pars plana corporis ciliaris the fibroblasts of the cortical tissue layer of the vitreous body of the infant eye are also found deep down in the sinus and folds of the ciliary epithelium. Thus they guarantee an as large as possible area for the attachment of the fibrils of the zonula fibres which they produce.The pars plana corporis ciliaris of the infant eye is covered with a dense network of fibroblast processes. Also cells of the macrophage type may be found in this region.Our electron microscopical findings confirm those of earlier light microscopists and lately by Balazs. The vitreous body of the eye is formed by mesenchymal tissue, whereas the zonula fibres are formed by connective tissue.

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Mit dankenswerter Unterstützung durch den Schweizerischen Nationalfonds zur Förderung der Wissenschaftlichen Forschung.