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71.
C Sartori S Stefanini A Cimini A Di Giulio M P Cerù 《Biology of the cell / under the auspices of the European Cell Biology Organization》1992,74(3):315-324
The fatty-acyl-CoA beta-oxidation (FAO) and catalase activities, as well as membrane fluidity of liver peroxisomes of newborns from normal and clofibrate-treated rats were studied during the recovery period, ie, throughout the first week of postnatal life. In the test animals the enzyme activities, which are significantly higher than controls at birth return to normal levels showing a somewhat different time course with FAO rapidly decreasing to control values within three days but with catalase still higher than controls at day 6. The half-life and degradation rate (Kd) of FAO are identical to those calculated by us for the whole organelles and to those reported by others for total catalase in normal or clofibrate-treated adult animals in the presence of catalase inhibitors. Soluble catalase shows turnover values which are similar though not identical to those of FAO, while total catalase has a very long half-life and a low Kd. Peroxisomal membrane fluidity, as determined by fluorescence anisotropy of 1-anilinonaphthalene-8-sulfonate (ANS) bound to purified peroxisomal fractions is higher in tests than in controls, recovering normal values within 6 days. Our results demonstrate that liver peroxisomes of rats prenatally exposed to clofibrate return to control conditions within about 1 week. The turnover parameters of enzymes and the membrane fluidity values are discussed in terms of disposal mechanism(s) for the excess of induced peroxisomes. 相似文献
72.
Alba Vecchini Luciano Binaglia Paolo Di Nardo Marilena Minieri Giuseppe Tallarida 《Molecular and cellular biochemistry》1992,110(1):47-54
The activity of phospholipid base exchange enzymes has been evaluated in cardiac sarcolemmal membranes from Syrian Golden
hamsters and from a hamster strain (UM-X7.1) characterized by a genetic form of hypertrophic cardiomyopathy. No choline base
exchange activity and only a little serine base exchange activity were detected, whereas the ethanolamine base exchange enzyme
was found highly active in membranes from both strains. For this reason, the present study is focussed on the ethanolamine
base exchange enzyme. The apparent Km for ethanolamine of ethanolamine base exchange enzyme from Syrian Golden membranes and
from UM-X7.1 strain membranes are 18 and 32 μM, respectively. The specific activity of the sarcolemmal ethanolamine base exchange
enzyme is lower in the UM-X7.1 strain than in Syrian Golden hamsters. The calcium-dependence of the enzyme appears different
when the membranes from the two strains are compared. Indeed, after removal of the membrane-bound divalent cations, comparable
activities are found in both membrane preparations, whereas, upon addition of Ca2+ to the incubation mixtures, the activity of the enzyme is enhanced in the membranes from Syrian Golden strain more than in
those from UM-X7.1 strain. The cholesterol content of sarcolemmal membranes is higher in the cardiomyopathic strain than in
the Syrian Golden hamsters. A possible relation between changes of the membrane lipid composition and of the ethanolamine
base exchange activity is discussed. 相似文献
73.
Genomic potential of erythroid and leukocytic cells of Rana pipiens analyzed by nuclear transfer into diplotene and maturing oocytes 总被引:3,自引:0,他引:3
Marie A. Di Berardino Nancy Hoffner Orr 《Differentiation; research in biological diversity》1992,50(1):1-13
In order to determine whether differentiated somatic cells maintain genetic totipotency, nuclear transplantations from several differentiated somatic cell types into eggs and oocytes were performed previously in Rana pipiens and Xenopus laevis. The formation of postneurula embryos and tadpoles under the direction of the test nuclei demonstrated their genetic multipotency. In addition, Rana erythrocyte nuclei transplanted to oocytes directed more extensive tadpole development than those injected into eggs. We have extended our studies of the genomic potential of differentiated somatic nuclei from the peripheral blood of Rana pipiens. First, we show that the developmental potential of erythrocyte nuclei injected into oocytes at first meiotic metaphase was greater than those injected into diplotene oocytes. Second, we demonstrate that erythroblast and leukocyte nuclei transplanted to oocytes at first meiotic metaphase promoted more advanced tadpole development than those previously injected into Xenopus eggs. Third, erythrocyte nuclei were more successful in promoting advanced tadpole development compared with erythroblast and leukocyte nuclei. The results show that differentiated somatic nuclei transferred to the cytoplasm of oocytes at first meiotic metaphase display enhanced genomic and developmental potential over those transplanted to diplotene oocytes and eggs, at least for the three nuclear cell types tested from the peripheral blood. 相似文献
74.
R C de Oliveira D T Ribeiro R G Nigro P Di Mascio C F Menck 《Nucleic acids research》1992,20(16):4319-4323
In order to characterize the molecular nature of singlet oxygen (1O2) induced mutations in mammalian cells, a SV40-based shuttle vector (pi SVPC13) was treated with singlet oxygen arising from the thermal decomposition of the water-soluble endoperoxide of 3,3'-(1,4-naphthylidene) dipropionate (NDPO2). After the passage of damaged plasmid through monkey COS7 cells, the vector was shuffled into E. coli cells, allowing the screening of supF mutants. The mutation spectrum analysis shows that single and multiple base substitutions arose in 82.5% of the mutants, the others being rearrangements. The distribution of mutations within the supF gene is not random and some hotspots are evident. Most of the point mutations (98.4%) involve G:C base pairs and G:C to T:A transversion was the most frequent mutation (50.8%), followed by G:C to C:G transversion (32.8%). These results indicate that mutagenesis in mammalian cells, mediated by 1O2-induced DNA damage, is targeted selectively at guanine residues. 相似文献
75.
Identification of regulatory elements within the minimal promoter region of the human endogenous ERV9 proviruses: accurate transcription initiation is controlled by an Inr-like element. 下载免费PDF全文
G La Mantia B Majello A Di Cristofano M Strazzullo G Minchiotti L Lania 《Nucleic acids research》1992,20(16):4129-4136
76.
Regional expression of the homeobox gene Nkx-2.2 in the developing mammalian forebrain. 总被引:11,自引:0,他引:11
M Price D Lazzaro T Pohl M G Mattei U Rüther J C Olivo D Duboule R Di Lauro 《Neuron》1992,8(2):241-255
77.
78.
M Bernardi B Di Sarra G Montecchiani L Re L Rossini C Tonnini 《Bollettino della Società italiana di biologia sperimentale》1991,67(1):47-54
Spontaneous fluctuations in heart rate were analyzed by spectral analysis in the ether anesthetized and pithed adult rat. In order to investigate the changes in the spectral pattern of the fluctuations, the selective 5HT-2 and -3 isoreceptor blockers ritanserin and BRL 43694A were used. In both the experimental conditions, ritanserin blockade led to dose-dependent increased fluctuations in HR low and high frequencies. In both the anesthetized and pithed rats, the low frequency range HR fluctuations were drastically reduced by BRL 43694A. 相似文献
79.
R Fiorella G Assennato V Di Nicola M Troia G A Colucci L Resta 《Bollettino della Società italiana di biologia sperimentale》1991,67(2):199-205
The presence of inflammatory reaction, plasma cells, and eosinophils in peritumoral connective tissue and in neoplastic stroma was evaluated with morphometrical method in 181 patients affected by laryngeal carcinoma. A logistic multiple regression model was applied making it with the use of an independent variable represented by the "infiltrating" or "expansive" types of tumor growth, in order to evaluate the probability of nodal metastatsis of each parameter. The results suggest an inverse correlationship between plasma cells and inflammatory infiltration and incidence of nodal metastatsis only in the comparison of the extreme conditions: those with scarce infiltration versus the ones with large infiltration. Inflammatory or plasmacellular infiltration may represent both a defense mechanism against cancer and an aspecific or allergic reaction. The eosinophilic infiltration shows no value in the prevention of nodal involvement. 相似文献