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51.
Alessandro Terrinoni Carmen Di Franco Patrizio Dimitri Nikolaj Junakovic 《Journal of molecular evolution》1997,45(2):145-153
The intragenomic location of the elements of the I, G, jockey, F, and Doc transposon families has been studied by the Southern
blot analysis, in 12 laboratory Drosophila melanogaster stocks. Elements located in euchromatin, heterochromatin, and on the Y chromosome are identified, and their stability has
been assessed by comparing the autoradiographs detected in different stocks and analysis of individual flies. Evidence is
shown suggesting that preferential location in euchromatin or heterochromatin and the distribution within heterochromatin
are distinctive of transposon families. Elements located in heterochromatin can be unstable. These results are discussed in
the context of the relationship between transposable elements and the host genome.
Received: 21 August 1996 / Accepted: 24 March 1997 相似文献
52.
Rafael Zapata Angels Navarro Enric I. Canela Rafael Franco Carmen Lluis Josefa Mallol 《Journal of neurochemistry》1997,69(6):2546-2554
Abstract: Identification of A1 adenosine receptors (A1 Rs) in a tumor cell line derived from rat pituitary (GH4 cells) was performed by ligand binding and immunological experiments. Subsequently, the involvement of A1 Rs in the regulation of calcium conductance was studied in these cells. The agonist N 6 -( R )-(2-phenylisopropyl)adenosine ( R -PIA) did not modify the intracellular calcium basal levels, whereas it inhibited the increase produced by 15 m M KCl depolarization. The antagonist 1,3-dipropyl-8-cyclopentylxanthine led to the opening of voltage-dependent cell surface calcium channels in the absence of exogenous KCl. The channels were of the L type because the effect was abolished by calciseptine and by verapamil. These results suggest that endogenous adenosine exerts a tonic inhibitory effect on calcium transport. This was confirmed by the high adenosine concentration found in cell supernatants (up to 1 µ M ) and by the calcium mobilization produced by exogenously added adenosine deaminase. In depolarizing conditions, the calcium peak in the presence of adenosine deaminase was reduced when cells were preincubated with R -PIA, thus suggesting that A1 R activation regulates the intensity of depolarization. These results demonstrate that adenosine is an important regulator of the physiological state of pituitary tumor cells by modulating, in an autocrine manner, the activity of L-type voltage-dependent calcium channels. 相似文献
53.
CD8+ T cells can mediate almost complete short-term and partial long-term immunity to rotavirus in mice. 总被引:7,自引:1,他引:6
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We have recently shown that CD8+ T cells mediate clearance of rotavirus infection in mice. B-cell-deficient J(H)D knockout (-/-) mice depleted of CD8+ T cells become chronically infected with murine rotavirus, and beta2 microglobulin -/- and other mice depleted of CD8+ T cells have a 1- to 4-day delay in clearance of primary rotavirus infection. A role for CD8+ T cells in protection from reinfection with rotavirus was suggested by these studies, because J(H)D -/- mice rechallenged 6 to 8 weeks after primary infection shed smaller quantities of viral antigen and for fewer days than naive mice. Here we show that 8, 11, 13, and 18 days after primary infection the J(H)D -/- mice are almost completely resistant to reinfection and that they are still partially protected from reinfection 6 weeks, 5 months, and 8 months after primary infection. Protection against reinfection was dependent on CD8+ T cells, since J(H)D -/- mice depleted of CD8+ T cells by administration of an anti-CD8 monoclonal antibody became chronically infected with rotavirus upon rechallenge 13 days, 18 days, 6 weeks, and 5 months after primary infection. Thus, CD8+ T cells can actively mediate almost complete short-term and partial long-term protection from reinfection. 相似文献
54.
Macarena Gomez-Lira Antonella Sangalli Monica Mottes Chiara Perusi Pier Franco Pignatti Nicolò Rizzuto Alessandro Salviati 《Human genetics》1995,96(4):417-422
-Hexosaminidase gene mutations were analyzed in two adult-onset Sandhoff disease Italian patients by PCR analysis of a common known mutation (5) and by heteroduplex analysis of genomic and RT-PCR DNA fragments, covering the whole gene. The patients' genotypes were 5/C1214T, and G890A/C1214T, respectively. As mutation C1214T (Pro405Leu) is also present in the other two late-onset cases so far described, we suggest that C1214T is a common mutation in this type of Sandhoff disease. Mutation G890A (Cys297Tyr) is a novel mutation which presumably causes altered processing of the pro chain. 相似文献
55.
The Drosophila runt gene, which controls early events in embryogenesis, has been shown to have homologues in human and mouse. The human gene on 21q22 is involved in the t(8;21) associated with acute myeloid leukemia. Two mouse runt-like loci encoding DNA-binding proteins have been identified. We report here the isolation and partial sequence of a molecular clone of a third mouse runt-like locus. By using a panel of somatic cell hybrids and interspecific backcross mice, we map the novel locus to the telomeric region of mouse chromosome 4. 相似文献
56.
Summary Angiotensin II-induced the hypertrophy of the cytoplasmic compartment and significantly increased (5-3H)uridine incorporation into RNA species by Conn's human adult adenomatous cells in primary tissue culture. On its own, bromocriptine, while enlarging only the nucleolar compartment, also intensely stimulated the incorporation of (5-3H)uridine into RNA species by the cultured adrenocortical adenomatous cells. However, an equimolar mixture of angiotensin II and bromocriptine was totally ineffective, eliciting no change in cellular morphometry or isotope incorporation with respect to the control specimens run in parallel.The present findings support the view that bromocriptine can influence the metabolism of Conn's cells directly at the cellular level by acting as an agonist-antagonist of angiotensin. 相似文献
57.
Rino Cella Roberta Colombo Maria Grazia Galli Erik Nielsen Franco Rollo Francesco Sala 《Physiologia plantarum》1982,55(3):279-284
Rice ( Oryza sativa L.) cells returning to in vitro culture after preservation at superlow temperature in liquid nitrogen are characterized by a number of physiological alterations. These include: reduction in respiration and glucose uptake, loss of intracellular potassium, decrease in the cellular level of key metabolites (ATP, glucose-6-phosphate and pyruvate) and fragility of protoplasts following the action of cell wall-degrading enzymes.
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time. 相似文献
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time. 相似文献
58.
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60.
1. CM-cellulose chromatography of a fraction soluble in 5% perchloric acid from Ceratitis capitata chromatin yields three proteins, C1a1, C1a2 and C1b, which have been purified to electrophoretical homogeneity. 2. C1a1, C1a2 and C1b analyse like high mobility group (HMG) non-histone chromosomal proteins, although they do not exactly correspond with those from vertebrates. It is proposed that C1 proteins, as well as Drosophila D1 [Rodríguez Alfageme et al. (1980) Chromosoma, 78, 1-31] are representative of a class of insect-specific HMG proteins. Tryptic fingerprints show that C1a1 and C1a2 are very similar, but C1b is a somewhat distinct protein. Circular dichroism studies have shown that these preparations do not appreciably fold on increasing ionic strength. 3. The interactions between DNA and C1 proteins have been studied. These proteins precipitate DNA in 0.15 M NaCl, 0.015 M sodium citrate and the precipitation curves are cooperative. Soluble complexes between C1 proteins and DNA could be prepared in low ionic strength media and their thermal denaturation profiles obtained. C1 proteins do not destabilize DNA under the conditions used to prepare the complexes but the three proteins stabilize DNA to a different degree. From these studies it has been concluded that the association constant of C1b to DNA is smaller than that of C1a1 and C1a2. 相似文献