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21.
Maurilio De Felice John Guardiola Werner Schreil Mark Levinthal Maurizio Iaccarino 《Molecular & general genetics : MGG》1977,156(1):9-16
Summary Some of the strains containing mutations in the genes for the acetolactate synthase isoenzymes are temperature sensitive (ts). Suppression of the acetolactate synthase defect due to one of these mutations suppresses also the ts phenotype; moreover, a genetic cross shows that the two phenotypes cannot be dissociated.The ts phenotype is accompanied by a decreased efficiency of transduction with Pl phage. Observations at the light microscope show formation of abnormal cells. Under specific conditions diaminopimelate stimulates growth and restores normal transduction efficiency. The rate of diaminopimelate formed and excreted by non-growing cells decreases when an acetolactate synthase mutation is present.We give evidence that the ts phenotype is due to an increased formation of lysine from diaminopimelate; this causes a starvation for the latter and therefore cell wall abnormalities. In fact, even at the permissive temperature, the lysine pool is 8x increased in a strain with an acetolactate synthase defect, while a slight decrease in the diaminopimelate pool is observed. Moreover, introduction into a ts strain of a mutation in lysA (the gene coding for diaminopimelate decarboxylase) cures the ts phenotype. Finally among the temperature resistant revertants we found some lysine auxotrophs. 相似文献
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Maurizio Rossetto Kingsley W. Dixon Eric Bunn 《In vitro cellular & developmental biology. Plant》1992,28(4):192-196
Summary Aeration of tissue cultured rare Australian plantsConostylis wonganensis S.D. Hopper (Haemodoraceae);Diplolaena andrewsii Ostenf.;Drummondita ericoides Harvey (Rutaceae);Eremophila resinosa F. Muell. (Myoporaceae);Eucalyptus ‘graniticola’ (Myrtaceae);Lechenaultia pulvinaris C. Gardner (goodeniaceae); andSowerbaea multicaulis E. Pritzel (Liliaceae) has been found to reduce vitrification in sensitive species as well as significantly improving shoot
quality and transfer to soil in most study species. A simple 7-mm hole with a double-layer insert of filter paper in the polypropylene
screw lids of the culture vessel decreased shoot vitrification over a 4-wk culture period. The method has implications for
facilitating the tissue culture of other rare Australian plants and reducing the occurrence of this developmental abnormality. 相似文献
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Giuseppe Fossati Andrea Balsari Donatella Taramelli Maria Luisa Sensi Giuseppe Pellegris Maurizio Nava Giorgio Parmiani 《Cancer immunology, immunotherapy : CII》1982,14(2):99-104
Summary Peripheral blood lymphocytes (PBL) of melanoma patients were sensitized in vitro with lymphocytes of a single donor or with a pool of lymphocytes of 5–20 different donors. After 6–7 days, the cytotoxic activity of the sensitized PBL was tested against cultured autologous tumor cells and lymphocytes in a 51Cr-release assay. Tumor lysis was observed in 13 of 16 cases in which patients' PBL (Pt-PBL) were stimulated by a pool of allogeneic lymphocytes and in five out of seven cases when single sensitization was performed. In no case was lysis of autologous normal lymphocytes or blasts seen. Cultivation of Pt-PBL with irradiated autologous tumor cells never led to the induction of lymphocytes cytotoxic to melanoma cells. Lysability by pool-activated autologous Pt-PBL of fresh cryopreserved tumor cells was compared to that of short-term cultured tumor cells, and no significant differences were observed. Cold-target inhibition experiments indicated that the cytotoxicity of Pt-PBL was tumor-restricted since only autologous melanoma cells but not lymphocytes were able to inhibit the reaction. These results indicate that activation of Pt-PBL is necessary in order to elicit or amplify their antitumor activity. 相似文献
27.
George W. Arana Ross J. Baldessarini Michael Herschel Maurizio Fava 《Life sciences》1981,29(2):121-133
The binding of low concentrations of [3H](?)apomorphine to preparations of calf and rat forebrain tissue was evaluated. Fractionation of crude homogenates to prepare a membrane fraction (P4) of striatal or caudate homogenates increased the proportion of saturable to total binding from 33% to over 80%, and increased the apparent density of binding sites from 94 to 681 fmol/mg protein. Binding in calf caudate P4 tissue was protein-dependent and optimal at pH = 7.0 to 7.5, and T = 20 to 25°C; at higher temperatures tissue binding sites appeared to degrade. The half-time of association and dissociation at 22°C were, respectively, 14.0 and 18.5 min; equilibration was complete in 60 min. Kinetic characteristics of high-affinity binding obtained from association and dissociation constants and from saturation isotherms were similar (Kd = 2.1 to 3.4 nM). The pharmacology of competition for 3H-APO suggests selectivity for dopamine-agonist interactions. These results indicate that the P4 membrane preparation may be useful for the evaluation of dopamine-agonist binding sites or “receptors.” 相似文献
28.
Maurizio Lambardi Kiran K. Sharma Trevor A. Thorpe 《In vitro cellular & developmental biology. Plant》1993,29(4):189-199
Summary Studies were undertaken to optimize tissue culture conditions for micropropagation of Aleppo pine (Pinus halepensis Mill.) from mature embryos and various explants of the embryo. Over 90% of the embryo explants gave rise to adventitious
buds within 4 wk. Intact embryos were the most suitable explants for shoot bud induction. Both isolated cotyledons and hypocotyls
produced adventitious buds, but these developed slowly and failed to elongate. N6-Benzyladenine (BA) alone at 5.0μM was the most effective cytokinin when added to gelled to gelled von Arnold and Eriksson’s (AE) medium containing 3% sucrose.
Adventitious bud development was achieved on hormone-free AE medium, and shoot elongation was optimum on three quarter-strength
Bornman’s MCM medium, with 0.1% conifer-derived activated charcoal. Shoots were multiplied on three-quarter strength MCM medium,
containing 5μM BA. To induce adventitious roots on the elongated shoots, pulse treatment with 1 mM IBA for 6 h, followed by the transfer of the shoots to sterile peat:vermiculite (1:1) mixture, was beneficial. After acclimatization
for 3 to 4 wk under mist, almost all the rooted shoots could be transplanted successfully to the greenhouse, where the plants
exhibited normal growth habit. Histologic studies on the ontogeny of adventitious shoot formation from mature embryo explants
revealed temporal structural changes in different parts of the explant. Induction of mitotic divisions on the shoot-forming
medium resulted in the formation of meristemoids in the epidermal and subepidermal layers of the explant, located initially
at both the tips of the cotyledons and the axils of adjacent cotyledons. Shoot buds arising in the axils of adjacent cotyledons
were due to new cell division and not to any preexisting meristem. 相似文献
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Corrochano S Renna M Tomas-Zapico C Brown SD Lucas JJ Rubinsztein DC Acevedo-Arozena A 《Autophagy》2012,8(3):431-432
Huntington and Parkinson diseases (HD and PD) are two major neurodegenerative disorders pathologically characterized by the accumulation of the aggregate-prone proteins mutant huntingtin (in HD) and α-synuclein (in PD). Mutant huntingtin is an autophagy substrate and autophagy modulators affect HD pathology both in vitro and in vivo. In vitro, α-synuclein levels are able to modulate autophagy: α-synuclein overexpression inhibits autophagy, whereas downregulation promotes autophagy. Here, we review our recent studies showing that α-synuclein levels modulate mutant huntingtin toxicity in mouse models. This phenotypic modification is accompanied by the in vivo modulation of autophagosome numbers in mouse brains from both control and HD mice expressing different levels of α-synuclein. 相似文献