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Piero A. Battaglia Franca Gigliani Liana Marcucci Raffaella Elli 《Molecular & general genetics : MGG》1987,209(1):41-48
Summary By using an artificial hybrid between phage and the pR plasmid, we have shown that the rep region of the pR plasmid encodes a function which regulates the expression of the muc genes (plasmid genes that are under the negative control of lexA and responsible for an increased rate of spontaneous mutagenesis and resistance to UV and chemicals). Expression of the muc genes was monitored by a fusion between the muc promoter and the lacZ structural gene. When E. coli cells containing such a fusion are infected by the hybrid pR phasmid, -galactosidase activity is enhanced, indicating that pR encodes an antagonist of lexA. By deletion mapping we have located the gene encoding the antagonist of lexA (bat) in the rep region of the plasmid. The bat gene product can also antagonize the cI repressor as shown by the observation that pR phasmids are virulent on a homoimmune lysogen. We have exploited this latter property to carry out genetic and functional analysis of the bat region. This region is organized as a classical operon where the expression of the bat structural gene is negatively regulated by a repressor gene that encodes a proteic product. 相似文献
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Roberta Colombo Raffaella Cerana Piera Lado Antonio Peres 《The Journal of membrane biology》1988,103(3):227-236
Summary The patch-clamp technique in whole-cell configuration was used to study the electrical properties of the tonoplast in isolated vacuoles fromAcer pseudoplatanus cultured cells. In symmetrical KCl or K2 malate solutions, voltage- and time-dependent inward currents were elicited by hyperpolarizing the tonoplast (inside negative), while in the positive range of potential the conductance was very small. The specific conductance of the tonoplast at –100 mV, in 100mm symmetrical KCl was about 160 S/cm2. The reversal potentials (E
rev) of the current, measured in symmetrical or asymmetrical ion concentrations (cation, anion or both) were very close to the values of the K+ equilibrium potential. Experiments performed in symmetrical or asymmetrical NaCl indicate that Na+ too can flow through the channels. NeitherE
rev nor amplitude and kinetics of the current changed by replacing NaCl with KCl in the external solution. These results indicate the presence of hyperpolarization-activated channels in tonoplasts, which are permeable to K+ as well as to Na+. Anions such as Cl– or malate seem to contribute little to the channel current. 相似文献
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Anna Maria Greco Pasquale Gambardella Raffaella Sticchi Diego D'aponte Pietro De Franciscis 《Chronobiology international》1988,5(3):217-225
Circadian rhythms of serotonin (5HT), its precursors tryptophan (TP) and 5-hydroxy-tryptophan (5HTP) and its acid catabolite 5-hydroxy-indoleacetic acid (5HIAA), were determined in the hypothalamus of control rats and rats which had been treated continuously with subcutaneous imipramine (10 mg/kg/day) for 2 weeks.
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
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The metabolism of glucose 1-phosphate and glucose 6-phosphate and their influence on the metabolism of glucose in rat-diaphragm muscle 总被引:6,自引:4,他引:2 下载免费PDF全文
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Raffaella Scardigli Silvia Soddu Rita Falcioni Marco Crescenzi Letizia Cimino Ada Sacchi 《Experimental cell research》1996,227(2):223
Integrin β4subunit is present in association with α6chain on both normal and transformed epithelial cells. Recently α6β4heterodimer was found on the endothelium of medium-sized blood vessels and on immature thymocytes. In this report we show, by Northern blotting, indirect immunofluorescence, immunoprecipitation, and Western blotting, that β4subunit is expressed also on cells of mesenchymal origin such as fibroblasts, myoblasts, and myotubes. Increased expression of α6β4has been related to the aggressive metastatic phenotype of human and murine carcinomas. The transforming growth factor β1(TGF-β1) has been found to modulate the expression of several integrins and intracellular matrix proteins, as well as to stimulate cell invasion and metastatic potential. To evaluate whether α6β4expression is modulated by TGF-β1, we transfected 3T3 fibroblasts with an expression vector carrying the human TGF-β1cDNA driven by the SV40 early promoter. We observed by indirect immunofluorescence a modification in the subcellular distribution of β4subunit, which acquires a perinuclear localization. This finding suggests this integrin subunit correlates with the cytoskeletal reorganization induced by TGF-β1. 相似文献
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Raffaella Balestrini Graziella Berta Paola Bonfante 《Biology of the cell / under the auspices of the European Cell Biology Organization》1992,75(3):235-243
Summary— Positional and structural modifications were demonstrated in nuclei of leek cells, after establishment of a symbiosis with two vesicular-arbuscular fungi, Glomus versiforme and Glomus E3. By combining light, immuno-electron microscopy and morphometry, the fungi were shown to have a direct effect on the host nuclear morphology: the effect was confined to a specific plant tissue (the cortical parenchyma) and to a moment of the fungal morphogenesis (the arbuscule). When they branch to form the complex structures called arbuscules in the inner parenchyma cells, the host nucleus migrates from the periphery of these cells towards their centre. In addition, it becomes larger and lobed, with a decondensed chromatin. A monoclonal antibody that mostly binds to the condensed chromatin revealed a significant decrease in gold labelling intensity over the nuclei of the colonized cells. These modifications suggest that the nuclear migration and the changes in chromatin organization are related to the modifications in gene expression observed during the establishment of mycorrhizal symbiosis. 相似文献