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31.
Teresa de Sa E Melo Patrice Morlière Sonia Goldstein René Santus Louis Dubertret Dominique Lagrange 《Biochemical and biophysical research communications》1984,120(2):670-676
5-methoxypsoralen (5-MOP) binds to human serum low density lipoproteins (LDL) according to a two-step process. Scatchard analysis of the first step yields K = 1.4 × 105 M?1 and 4 binding sites. It involves the LDL apoprotein. The second step corresponds to a solubilization, in the lipidic core, of ? 45 molecules of 5MOP per LDL molecule. It is accompanied by a large blue shift of the 5MOP fluorescence. The ability of LDL to bind 5MOP and to carry it into various cells may explain some biological effects sometimes encountered during PUVA therapy. 相似文献
32.
33.
Mario R. Tredici Teresa Papuzzo Luisa Tomaselli 《Applied microbiology and biotechnology》1986,24(1):47-50
Summary The results of a whole year experiment on the outdoor mass culture of Spirulina maxima strain 4Mx on fertilized sea-water are reported. Carbonate and phosphate precipitation in the sea-water media was prevented by maintaining a low concentration of phosphate and by controlling the pH in the range of 8.0–8.3. The mean annual yield of biomass on sea-water plus urea as nitrogen source was 7.35 g (dry weight) m-2· day-1, a value slightly lower than that obtained on the standard bicarbonate medium (8.14 g · m-2 · day-1). On sea-water plus nitrate the yield was only 5.2 g·m-2·day-1. The nitrogen content of the biomass was higher in summer and lower in winter. The seasonal effect was more evident when nitrate was the nitrogen source. 相似文献
34.
Teresa Garcia Pentti Tuohimaa Jan Mester Thierry Buchou Jack-Michel Renoir Etienne-Emile Baulieu 《Biochemical and biophysical research communications》1983,113(3):960-966
Preparations of the 90K and 110K components of the chick oviduct progesterone receptor (PR) purified to near homogeneity were tested for protein kinase activity. The 90K component was shown to incorporate radioactive phosphate from [γ-32P]-ATP in the presence of Ca2+ but not of Mg2+ ions, while the 110K component was phosphorylated in the presence of Mg2+, but not of Ca2+. The enzymatic activity of the 90K polypeptide appeared selective, since added proteins (histones) did not become phosphorylated. However, all proteins present in the 110K preparations were phosphorylated in the presence of Mg2+. These data suggest that components of the chick oviduct PR display protein kinase activity. 相似文献
35.
Cristina Rinaldi-Garaci Enrico Garaci Vera Del Gobbo Cartesio Favalli Teresa Jezzi Allan L. Goldstein 《Cellular immunology》1983,80(1):57-65
The effects of thymosin-α1 on the stimulation of specific release of prostaglandin E2 (PGE2) from splenic lymphocytes and thymocytes were studied. Experiments were also performed to study in parallel the absolute levels of thymosin-α1 in the blood and the induction of serum FTS activity and of azathioprine sensitivity of spleen cells from adult thymectomized (ATx) mice. A significant difference in the release of PGE2 between normal splenocytes and splenocytes from ATx mice was observed. Thymosin-α1 at certain concentrations was able to stimulate PGE2 release from lymphocytes of ATx mice while inhibiting release in lymphocytes of normal mice. Also, thymocytes were stimulated to release PGE2 after incubation with α1 in a manner similar to that seen in spleen cells of ATx mice. Approximately the same concentration of α1 was found to also correct the low azathioprine sensitivity of splenocytes from ATx mice. Determinations of FTS-like activity in the blood and the pharmacokinetics of α1 after administration of this synthetic molecule show a clear dissociation. A maximum peak of α1 activity was obtained after 1 hr, while maximal FTS-like activity was observed after 24 hr. The inhibition of the induction by α1 of FTS-like activity and of Thy 1.2 antigen by indomethacin suggests that the action of α1 requires prostaglandin biosynthesis. 相似文献
36.
Dilution of 14C-sucrose solution by intracellular fluid released as a result of ultracentrifugation was used to estimate the intracellular fluid volume of L cells. Consistent relationships to total cell volume as estimated by use of an electronic particle counter were obtained. Expressed as a percentage of total cell volume, the mean value plus or minus the S.D. for 6 experiments was 72.8 ± 0.9. 相似文献
37.
Effect of nitrate on the synthesis and decay of nitrate reductase of Neurospora 总被引:11,自引:0,他引:11
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George J. Sorger Maria Teresa Debanne Jacqueline Davies 《The Biochemical journal》1974,140(3):395-403
1. A method was developed to examine the turnover of nitrate reductase by the use of tungstate. 2. Evidence is presented which suggests that the disappearance of nitrate reductase activity from Neurospora mycelia exposed to non-inducing conditions is due to the disappearance of the enzyme protein(s) from the mycelia, and not merely due to the disappearance of its (their) catalytic power. 3. The presence of NO(3) (-) in the culture medium slows down the rate of degradation of nitrate reductase in Neurospora in vivo. 相似文献
38.
Jan Zarzycki Alina Peryt Barbara Klubińska Teresa Hajac Krystyna Żak 《Histochemistry and cell biology》1969,18(4):314-320
Zusammenfassung Es wurden mit histochemischen Methoden Milchdrüsen von Meerschweinchen in physiologischer und durch Kastration während der Laktationsperiode hervorgerufener Involution untersucht. Nachgewiesen wurden alkalische und saure Phosphatase (APh und SPh), unspezifische Esterase, Sukzinodehydrase, SH-Gruppen, Nukleinsäuren und Lipide. — Die Aktivität der SPh nimmt während der Involution zu. Die Bedeutung dieses Enzyms für den Rückbildungsprozeß des Drüsengewebes wird diskutiert. — Das Vorkommen der APh-Aktivität in Drüsenendstücken im Involutionsstadium kann auf die Beteiligung dieses Enzyms an der Rückresorption der mit der Milch ausgeschiedenen Substanzen hinweisen. — Zwischen der Aktivität der unspezifischen Esterase und dem Gehalt sowie der Lokalisation von Lipiden besteht eine Abhängigkeit. — Es konnten keine Unterschiede in der Sukzinodehydraseaktivität und dem DNS-Gehalt aufgezeigt werden. — Die Verminderung von SH-Gruppen und RNS hängt mit dem Aufhören der Sekretionsproduktion durch die Zellen der Drüsenendstücke der Milchdrüsen zusammen.
Histochemical studies on the involution mechanism of the mammary gland
Summary Histochemical methods were used to study mammary glands of guinea pigs in the course of physiologic involution and that induced by castration during lactation. Alkaline and acid phosphatases, unspecific esterase, succinic dehydrogenase, SH groups, nucleic acids and lipids were determined. Acid phosphatase activity was found to be increased in mammary glands, subject to involution. The participation of the enzyme in the involutionary process of the gland tissue is discussed. The distribution of alkaline phosphatase in the secretory sections of the gland during involution would suggest the participation of the enzyme in the reabsorption of the substance secreted with milk. A correlation existing between the activity of unspecific esterase, the level and distribution of lipids in the mammary gland could be established. No differences were detected in the activity of succinic dehydrogenase and DNA level. A decrease in SH groups and RNA content is related to cessation of milk secretion.相似文献
39.
The DNA region essential for replication and stability of a native plasmid (pTM5) from Rhizobium sp. (Hedysarum) has been identified and isolated within a 5.4-kb PstI restriction fragment. The isolation of this region was accomplished by cloning endonuclease-restricted pTM5 DNA into a ColE1-type replicon and selecting the recombinant plasmids containing the pTM5 replicator (pTM5 derivative plasmids) by their ability to replicate in Rhizobium. DNA homology studies revealed that pTM5-like replicons are present in cryptic plasmids from some Rhizobium sp. (Hedysarum) strains but not in plasmids from strains of other Rhizobium species or Agrobacterium tumefaciens. The pTM5 derivative plasmids were able to replicate in Escherichia coli and A. tumefaciens and in a wide range of Rhizobium species. On the basis of stability assays in the absence of antibiotic selective pressure, the pTM5 derivative plasmids were shown to be highly stable in both free-living and symbiotic cells of Rhizobium sp. (Hedysarum). The stability of these plasmids in other species of Rhizobium and in A. tumefaciens varied depending on the host and on the plasmid. Most pTM5 derivative plasmids tested showed significantly higher symbiotic stability than RK2 derivative plasmids pRK290 and pAL618 in Rhizobium sp. (Hedysarum), R. meliloti, and R. leguminosarum bv. phaseoli. Consequently, we consider that the constructed pTM5 derivative plasmids are potentially useful as cloning vectors for Rhizobiaceae. 相似文献
40.
Summary In a strain ofSaccharomyces cerevisiae, acetic acid at concentrations up to 1% (v/v) depressed the tolerance to added ethanol, from 11% (v/v) down to zero, and simultaneously narrowed the temperature range of growth from 3–42°C to 19–26°C. In addition, acetic acid shifted the associative temperature profile of growthand death to lower temperatures, and depressed the growth yield on glucose. 相似文献