Recombinant interferon-beta 2 (interleukin-6) induces myeloid differentiation

Human IFN-beta 2 cytokine produced in E. coli was purified to homogeneity by immunoaffinity and ion-exchange chromatography. The cytokine inhibits the growth of myeloleukemic M1 cells and induces their morphological and functional differentiation into macrophages. Differentiation was also observed in the histiocytic lymphoma U937 cells. The effect on U937 was synergized by IFN-gamma and under these conditions IFN-beta 2 produced the induction of (2'-5') oligo(A) synthetase typical to IFN action and to differentiation.     

Hybridization of DNA from methanogenic bacteria with nitrogenase structural genes (nifHDK)

Summary Using the Southern hybridization technique, homologies were examined between restricted DNA of four methanogenic bacteria (Methanobacterium ivanovi, Methanobacterium thermoautotrophicum, Methanococcus voltae, Methanosarcina barkeri) and the nif (nitrogen fixation) genes of Klebsiella pneumoniae and Anabaena strain 7120. With K. pneumoniae probes, no hybridization was observed with nifA, nifNE, and nifJ but positive results were obtained with the nifHDK genes coding for nitrogenase. Homology was detected, in the four strains, with K. pneumoniae and Anabaena nifH probes. In M. voltae and M. ivanovi, the homology found with nifH was estimated to be about 70% and a weaker hybridization was observed also with nifD and nifK. In M. voltae, the sequence homologous to nifH was found on a 3.0 kbp HindIII fragment and sequences homologous to nifD and nifK on a 3.8 kbp HindIII fragment. The 3.0 kbp fragment was cloned and the region homologous to nifH was localized more precisely. When this fragment was used as a probe against other DNAs, it behaved as a K. pneumoniae and Anabaena nifH probe. The results suggest that the structural genes for nitrogenase may be present in archaebacteria and raise interesting questions regarding their evolution.     

Gamma-T4 hybrid bacteriophage carrying the thymidine kinase gene of bacteriophage T4.

Among 32 lambda-T4 recombinant phages selected for growth on a thymidylate synthetase-deficient (thyA) host, 2 were shown to carry the T4 thymidine kinase (tk) gene. The lambda-T4tk phages contain two T4 HindIII DNA fragments (2.0 and 1.5 kilobases) that hybridize to restriction fragments of T4 DNA, encompassing the tk locus at 60 kilobases on the T4 map. The T4tk insert compensates for the simultaneous host deficiencies of thymidine kinase and thymidylate synthetase in a thymidine kinase-deficient (tdk) host growing in the presence of fluorodeoxyuridine when provided with thymidine and uridine. The lambda-T4tk hybrid phages specified five polypeptides with Mrs of 22,000 (22K), 21K, 14K, 11K, and 9K.     

Callus formation and induction of a cell suspension culture from Acacia senegal

Cell proliferation has been induced from the cambial zone of a branch of Acacia senegal, kept on the basal Knop and Ball medium in the presence of auxin. Transferred on the more complete nutrient medium of Schenk and Hildebrandt, the colonies gave rise to several cell lines. One of the friable lines, consisting of aggregates of parenchymatous cells, gave a cell suspension culture in an agitated liquid medium which is maintained as a strain of illimited growth. The heterogeneous suspension did not undergo noticeable changes after eight transfers. Aggregates collected on a 1000-m nylon seive were able to grow on a solid medium and gave back a friable callus similar to the initial colonies.     

Differential regulation of HLA-DR mRNAs and cell surface antigens by interferon

Human interferons-alpha, -beta and -gamma enhance HLA-DR mRNAs in all the human lymphoblastoid and melanoma cell lines studied. The increase concerns both alpha and beta chain mRNAs. Moreover, we show that immune interferon-gamma preferentially enhances class II MHC mRNA. This effect of IFN-gamma on the synthesis of alpha and beta HLA-DR chains has been also analysed by immunoprecipitation. It is abolished by a monoclonal antibody directed against human IFN-gamma. The effect of interferon on the cell surface level of HLA-DR molecules does not always correspond to the enhancement of HLA-DR mRNA. Our experiments suggest that this discrepancy between the enhancement of HLA-DR mRNA and cell surface antigen might be due to a constitutively high level of the corresponding antigens on several of the human cells studied.     

Interferon-induced 56,000 Mr protein and its mRNA in human cells: molecular cloning and partial sequence of the cDNA.

Treatment of responsive cells by interferons (IFNs) induces within a few hours a rise in the concentration of several proteins and mRNAs. In order to characterize these IFN-induced mRNA species, we have cloned in E. coli the cDNA made from a 17-18S poly(A)+ RNA of human fibroblastoid cells (SV80) treated with IFN-beta. We describe here a pBR322 recombinant plasmid (C56) which contains a 400 bp cDNA insert corresponding to a 18S mRNA species newly induced by IFN. The C56 mRNA codes for a 56,000 dalton protein easily detectable by hybridization-translation experiments. The sequence of 66 of the carboxy-terminal amino-acids of the protein can be deduced from the cDNA sequence. IFNs-alpha, beta or gamma are able to activate the expression of this gene in human fibroblasts as well as lymphoblastoid cells. The mRNA is not detectable without IFN; it reaches maximum levels (0.1% of the total poly(A)+ RNA) within 4-8 hrs and decreases after 16 hrs.     

HIBERNATION CHEZ TROIS ESPÈCES DE MÉTOPIINES: HYMENOPTERA,ICHNEUMONIDAE

Résumé Les conditions de l'hibernation sont étudiées chez les trois espèces de Métopiines Chorinaeus funebris Gravenhorst, Triclistus podagricus Gravenhorst et Triclistus pygmaeus Cresson. Ces espèces hibernent à des stades de développement compris entre l'éonymphe et l'adulte non émergé (Tableau I). La durée de l'incubation complémentaire après réactivation par le froid à 2^o varie entre 10 et 30 jours en moyenne (Tableaux II, IV et V). Chez T. podagricus et T. pygmaeus, on a observé également des émergences d'adultes avant l'hiver (Tableau III). I1 semble que T. podagricus ne parvienne au stade d'imago hibernant qu'après une baisse de la température d'élevage. Aucune souche dépourvue de diapause n'a pu être créée, mais pour les trois espèces, deux générations annuelles seraient possibles sous conditions contrôlées. Enfin, l'utilisation éventuelle de T. pygmaeus pour une lutte biologique contre Zeiraphera diniana Guénée est évoquée.

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Summary The conditions of hibernation have been investigated in the three metopiine species Chorinaeus funebris, Triclistus podagricus and Triclistus pygmaeus, all entomophagous on Zeiraphera diniana Guénée (Lepidoptera, Tortricidae) in the Engadine Valley (Switzerland). The hibernating stages are eonymph, pronymph or unemerged adult inside the host pupae (Table I). The length of the complementary incubation after reactivation at 2^o varies between 10–30 days (Tables II, IV and V). A small number of T. podagricus and of T. pygmaeus regularly appear as adults before winter, in rearings of both laboratory and field populations (Table III). It seems that T. podagricus larvae need a reduction in the initial rearing temperature before full development is achieved and the hibernating stage is reached (imago). No strain without diapause could be obtained for any of the three species, but the rearing of two annual generations under controlled conditions is possible in the laboratory. The eventual use of T. pygmaeus as a control agent against Z. diniana is discussed.