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Annie Conter Dominique Dupouy Christine Delteil Hubert Planel 《Archives of microbiology》1986,144(3):286-290
Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomittant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.Abbreviations mGy
milli-Gray
- SOD
superoxide dismutase
- G6P-DH
glucose-6-phosphate dehydrogenase
- GAP-DH
glycer-aldehyde-3-phosphate dehydrogenase
- GSSG
oxidized glutathione 相似文献
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Location of Homologous DNA Sequences Interspersed at Five Regions in the Baculovirus AcMNPV Genome 总被引:21,自引:19,他引:2 下载免费PDF全文
An examination of Autographa californica nuclear polyhedrosis virus DNA revealed the presence of five interspersed regions, rich in EcoRI restriction sites, which shared homologous sequences. These homologous regions (hr), designated hr1 to hr5, occur at or near the following EcoRI fragment junctions: hr1EcoRI-B—EcoRI-I (0.0 map units); hr2, EcoRI-A—EcoRI-J (19.8 map units); hr3, EcoRI-C—EcoRI-G (52.9 map units); hr4, EcoRI-Q—EcoRI-L (69.8 map units); and hr5, EcoRI-S—EcoRI-X (88.0 map units). Four of these regions were identified, by cross-blot hybridization of HindIII-restricted A. californica nuclear polyhedrosis virus DNA, to be within the HindIII-A/B, -F, -L, and -Q fragments. The location of these regions and the identification of a fifth homologous region were confirmed, and their characterization was facilitated, by using two plasmids with HindIII-L or -Q fragment insertions, which contained the homologous regions hr2 and hr5, respectively. The sizes of the homologous regions were about 800 base pairs for hr2, 500 base pairs for hr5, and less than 500 base pairs for hr1, hr3, and hr4. A set of small EcoRI fragments (EcoRI minifragments) which ranged in size from 225 to 73 base pairs were detected in A. californica nuclear polyhedrosis virus DNA and HindIII-L and -Q fragments by polyacrylamide gel analysis. Some of the minifragments in viral DNA were present in extramolar amounts and corresponded in size to some of the minifragments present in HindIII-L and -Q. Clones of some of the EcoRI minifragments were used as probes in hybridizations to digests of viral DNA and of HindIII-L and -Q. The hybridization data, obtained under various levels of stringency, suggested that there was a degree of mismatching between the sequences which were responsible for the homology. 相似文献
78.
Klaus Hallermayer Christine Harmening Herbert Merz Bernd Hamprecht 《Journal of neurochemistry》1983,41(6):1761-1765
The benozomorphan derivative (-)-2-[2-(p-bromoacetamidophenyl)ethyl]-5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphan (BAB), capable of reacting with nucleophilic groups, acts on neuroblastoma X glioma hybrid cells as a potent, irreversible opiate agonist. Its potency in inhibiting the increase in cellular cyclic AMP, evoked by prostaglandin E1, is comparable to that of Leu-enkephalin. This also applies to its capacity to compete with [3H]D-Ala2-Met-enkephalinamide ([3H]DAEA) in binding on cell membrane preparations. The comparatively lower potency of (-)-2-[2-(p-acetamidophenyl)-ethyl]-5,9 alpha-dimethly-2'-hydroxy-5,7-benzomorphan (AB), which differs from BAB in the substitution of the bromoacetamido group by an acetamido group, is of the same order of magnitude as that of morphine. The covalent interaction of BAB with the opiate receptors is deduced from the observations that (1) it is not possible to wash away this compound from the receptors, (2) the potency of BAB in inhibiting the specific binding of [3H]DAEA increases with prolonged preincubation time, and (3) AB behaves as a reversible agonist. 相似文献
79.
Y.M. Bhatnagar R.D. Faulkner 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1983,739(1):132-136
Electrophoretic analysis of the nucleosomal histones from MN1 and MN2 subpopulations of the seminiferous tubules in gels containing either 6.25 or 2.5 M urea revealed the presence of testis specific histone H2S, H1 and protein ‘A’ in addition to the somatic histones in the core protein complex. Size analysis indicated the presence of a 150–160 bp DNA segment in the MNI subpopulation, whereas, an approx 180 bp DNA fragment was present in the MN2 subpopulation of both liver and tubule nucleosomes. These data suggest an extensive remodeling of the nucleosomal core protein complex during mammalian spermatogenesis. 相似文献
80.
Christine Jolicoeur Josette Noël Léa Brakier-Gingras 《Biochemical and biophysical research communications》1983,115(1):153-158
Polysomes from the skeletal muscle of normal and dystrophic hamsters were dissociated into ribosomal subunits by treatment with puromycin and the subunits from both strains were reassociated in all possible combinations. When their protein synthesis activity was assayed in a poly(U)-directed cell-free system at a low magnesium concentration, the reassociated ribosomes from dystrophic hamsters were less active than the ribosomes from control animals. The ribosomal defect is a property of the 60S subunit and is due to a ribosomal component rather than to abnormal binding of a non-ribosomal protein. 相似文献