Effect of acriflavine on the radiation resistance enhancement induced by cysteine treatment inEscherichia coli B/r

Zusammenfassung Zur Prüfung der Strahlenresistenz vonEscherichia coli nach bewährter Methode wird Acriflavin, ein DNA-Reparaturhemmer, zugegeben und es wird festgestellt, dass die Strahlenresistenz auch unter Cysteinschutz sinkt.     

Early effect of poliomyelitis virus on 5'-nucleotidase activity in HeLa cells]

One of the earlier effects of poliovirus was the maintaining of a high level of Hela cells 5'-nucleotidase activity (maximal efficiency for a virus/cell ratio = 500 ID 50/cell) (ID50:50% Infections Dose). The activity decreased when cells were suspended in the presence of EDTA(EDTA:Ethylene Diamine Tetracetic Acid) and was partially restored by adding 10 mM Mg++ interactions are discussed.     

On the expansion-contraction rhythm of the sea anemone,Actinia equina L.

Riassunto È stato studiato il ritmo di espansione-contrazione di esemplari diActinia equina L. della zona interoctidale del Mar Tirreno, sottoposti a condizioni differenti di illuminazione e di livello d'acqua. Gli autori ritengono che il ritmo sia direttamente dipendente dall'illuminazione ambientale e dallo stato di copertura o scopertura conseguente alle maree. Una luce di intensità pari a quella lunare non esercita alcuna influenza sul ritmo.

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Research supported with a grant of the Consiglio Nazionale delle Richerche.     

Possible stimulatory effect of retinoic acid on pulmonary macrophages.

Retinoic acid was administered to hamsters suffering from N-nitroso-N-methylurethane-induced fibrosing alveolitis. A significant increase in macrophage numbers was seen in the lungs of retinoid-treated animals as compared to the unsupplemented group.     

Inhibition by syngenic erythrocytes of in vitro growth of colonics from murine bone marrow cells

Summary The growth of colonies from murine bone marrow cells in soft agar cultures was found to be inhibited by 0.1 ml or more 50% washed syngenic erythrocyte suspension per 1.2 ml culture volume.     

Steroid hormones in the testicular tissue ofGallus domesticus

Riassunto Nel tessuto testicolare diGallus domesticus sono stati identificatii seguenti ormoni steroidi: pregnenolone (127 µg/kg), progesterone (66,5 µg/kg), androstenedione (2,4 µg/kg), testosterone (35 µg/kg), 20-idrossipregn-4-ene-3-one (30,5 µg/kg). Questi risultati dimostrano che il testicolo di pollo secerne gli steroidi della principale via biosintetica degli androgeni. La concentrazione relativamente alta di 20-idrossipregn-4-ene-3-one viene discussa alla luce delle ricerche sul metabolismo in vitro del progesterone.

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This investigation was supported by a research grant No. HD 01477-07 from the National Institute of Child Health and Human Development, Public Health Service, USA, and by the Consiglio Nazionale delle Ricerche of Italy.     

Formation of N-glucuronide of desmethylimipramine in the dog

Zusammenfassung Nach Verbreichung von Imipramin oder Desmethylimipramin bilden Hunde neben den bekannten Metaboliten Konjugate von Desmethylimipramin (und in kleineren Mengen von Desdimethylimipramin). Die Befunde sprechen für aliphatische N-Glukuronide und damit für einen bisher kaum beschriebenen Typus von Arzneimittelmetaboliten.

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Acknowledgment. We are indebted to the Swiss National Science Foundation for support and to Dr.R. Preisig for the use of facilities at the Institute of Clinical Pharmacology, University of Berne.     

Site-specific DICER and DROSHA RNA products control the DNA-damage response

Non-coding RNAs (ncRNAs) are involved in an increasingly recognized number of cellular events. Some ncRNAs are processed by DICER and DROSHA RNases to give rise to small double-stranded RNAs involved in RNA interference (RNAi). The DNA-damage response (DDR) is a signalling pathway that originates from a DNA lesion and arrests cell proliferation3. So far, DICER and DROSHA RNA products have not been reported to control DDR activation. Here we show, in human, mouse and zebrafish, that DICER and DROSHA, but not downstream elements of the RNAi pathway, are necessary to activate the DDR upon exogenous DNA damage and oncogene-induced genotoxic stress, as studied by DDR foci formation and by checkpoint assays. DDR foci are sensitive to RNase A treatment, and DICER- and DROSHA-dependent RNA products are required to restore DDR foci in RNase-A-treated cells. Through RNA deep sequencing and the study of DDR activation at a single inducible DNA double-strand break, we demonstrate that DDR foci formation requires site-specific DICER- and DROSHA-dependent small RNAs, named DDRNAs, which act in a MRE11–RAD50–NBS1-complex-dependent manner (MRE11 also known as MRE11A; NBS1 also known as NBN). DDRNAs, either chemically synthesized or in vitro generated by DICER cleavage, are sufficient to restore the DDR in RNase-A-treated cells, also in the absence of other cellular RNAs. Our results describe an unanticipated direct role of a novel class of ncRNAs in the control of DDR activation at sites of DNA damage.