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71.
Interferon affects intracellular calmodulin levels 总被引:1,自引:0,他引:1
Marie-Françoise Bourgeade Françoise Besançon Ming Nguy Thang 《Biochemical and biophysical research communications》1983,111(2):430-437
Interferon lowers calmodulin levels in two cell lines sensitive to its antiproliferative effect. Further, in synchronized cells, interferon strongly inhibits the increase in calmodulin observed when control cells enter the S phase, and concomitantly inhibits DNA synthesis. Calmodulin has been implicated in the control of cell proliferation and an increase in this protein seems to be necessary for the progression of cells into the S phase of the cell cycle. Therefore, the effect of interferon on calmodulin content might constitute part of the molecular mechanism by which interferon inhibits DNA synthesis. 相似文献
72.
Tn7, a transposon of 14 kb, encodes resistance to trimethoprim (Tp) and streptomycin (Sm). A cleavage site map of this transposon for twenty-two different restriction enzymes as determined by comparison of restriction enzyme cleavage patterns of the plasmids ColE1 and ColE1::Tn7 is presented. The precise localization of these sites was facilitated by the use of two deletion derivatives of ColE1::Tn7: pGB2 and ColE1::Tn7Δ6, and by the use of pOB14 and pOB15 which contain a part of Tn7 cloned into the plasmid pBR322. This map should aid in the study of the structural and genetic organization of this transposon. 相似文献
73.
74.
Résumé Le virus de la densonucléose (VDN) conserve une partie de sa virulence en solution aqueuse entre 0°C et 30°C pendant deux
mois. Son pouvoir infectieux se maintient à—10°C pendant deux mois mais est supprimé après dix jours de dessication. On peut
done considérer ceParvovirus d’Insectes comme un virus relativement résistant aux températures que l’on rencontre ordinairement dans la nature et au laboratoire.
Ce travail a été réalisé en partie dans le cadre d’une convention I.N.R.A.-D.R.M.E. 相似文献
Summary The persistence of DNV is described. This virus retains a part of its infectivity in aqueous solution between 0°C and 30°C. The log LD50 initially 7,15 drops to 2 after two months. The virus keeps its infectivity at 10°C but it loses all its pathogenicity after 10 days in dry conditions.
Ce travail a été réalisé en partie dans le cadre d’une convention I.N.R.A.-D.R.M.E. 相似文献
75.
The conformation in solution of derivatives of methyl hexopyranosides has been studied by n.m.r. The esters of methyl 2,3-O-isopropylidene-α-D-manno- and -talopyranosides as well as their 4-deoxy-4-C-methyl analog having a manno configuration exist mainly in a flattened (4,0F) chair conformation (4C1). The presence in the talo epimer of the 4-deoxy-4-C-methyl analog of the bulky methyl group on the endo side of the bicyclic system results in a skew form (3S1). The methyl 4-deoxy-2,3-O-isopropylidene-4-C-methylene-α-D-lyxo-hexopyranosides monosubstituted at C-4′ adopt, in solution, a conformation close to 3S1, whichever their configuration (cis or trans) at the double bond, as indicated by their allylic coupling constants. 相似文献
76.
Zusammenfassung In normalen Leberzellen der Maus wurde das quantitative Verhalten des perimitochondrialen granulären endoplasmatischen Retikulums untersucht. 74% der Mitochondrien zeigen Beziehungen zum granulären endoplasmatischen Retikulum. Die einzelnen Mitochondrien werden zu 52%19,5 von den Membranen des granulären endoplasmatischen Retikulums bedeckt. Je Mikrometer Membranstrecke sind auf der mitochondriennahen Seite des granulären endoplasmatischen Retikulums 21 und auf der mitochondrienfernen Seite 20 Ribosomen zu finden, was der Zahl im übrigen granulären endoplasmatischen Retikulum entspricht. Die Befunde stellen die Grundlage für Untersuchungen des perimitochondrialen granulären endoplasmatischen Retikulums unter pathologischen Bedingungen dar.
Structure and quantitative behaviour of the perimitochondrial granular endoplasmic reticulum in the liver cells of the mouse
Summary The perimitochondrial granular endoplasmic reticulum in normal mouse liver cells has been investigated quantitatively. 74% of the mitochondria are in association with the granular endoplasmic reticulum. The individual mitochondrion is covered by the membranes of the granulated E. R. in 52%19.5. The outer surface of the endoplasmic membrane, facing the mitochondrion, is occupied by 21 ribosomes per m; the corresponding surface of the membrane facing the free cytoplasm is occupied by 20 ribosomes per m. These data are in agreement with those of that fraction of the E. R., which is not in association with mitochondria. These findings represent a basis for investigations of the perimitochondrial endoplasmic reticulum under pathological conditions.相似文献
77.
In this study, retting was carried out by Aspergillus niger. The pH, galacturonic acid (GA), and total reducing sugar were determined; the end point was identified by the classic empirical processes and by the maximal GA content of the retting water. The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes. Control of total acidity was not required, since the pH remained close to neutrality throughout the entire process. 相似文献
78.
Summary In contrast to the situation found in two classes of warm-blooded vertebrates, mammals and birds, the class Reptilia is not uniform with regard to total genetic content; rather, it contains two distinct categories. The close cytological kinship between snakes and birds was revealed. Both are almost identical in total genetic content, which is about 50 per cent that of placental mammals. Both have microchromosomes, as well as Z-chromosomes very similar in absolute size, comprising nearly 10 per cent of the homogametic haploid (AZ) set. This leads to the implication that snakes and birds originated from the same lineage, and that their Z-chromosomes have not changed substantially since the Jurassic period of the Mesozoic era, about 180 million years ago.Within the reptilian suborder Serpentes, the step-by-step differentiation from the primitive ZW pair to the grossly heteromorphic ZW pair could be observed. In the ancient family Boidae, the sex chromosomes were still homomorphic to each other. In the family Colubridae, the beginning of heteromorphism was manifested in two ways. In some species, a pericentric inversion on the W caused it to differ from the Z; in others, duplication of the W occurred. In the family Crotalidae, the W had apparently achieved its very specialized status; it was a distinctly smaller element.In Säo Paulo, this work was supported by Fundacão de Amparo a Pesquisa do Estado de São Paulo e Fundo de Pesquisas do Instituto Butantan. In Duarte, this work was supported in part by grant CA-05138-05, National Cancer Institute, U. S. Public Health Service. Contribution No. 36-64, Department of Biology, City of Hope Medical Center. 相似文献
79.
80.
François M. Catzeflis Eviatar Nevo Jon E. Ahlquist Charles G. Sibley 《Journal of molecular evolution》1989,29(3):223-232
Summary DNA-DNA hybridization was used to measure the average genomic divergence among the four chromosomal species of the Eurasian mole rats belonging to theSpalax ehrenbergi complex (Rodentia: Spalacidae). The percent nucleotide substitutions in the single-copy nuclear DNA among the species ranged from 0 to 5%, suggesting that speciation has occurred with minor genomic changes in these animals. The youngest chromosomal species appear to differ by 0.2–0.6% base pair mismatch, which is only between one and three base differences in a 500-bp fragment. The interspecific values of percent nucleotide differences permit the recognition of two well-separated speciation events in theS. ehrenbergi complex, the older (of Lower Pleistocene age) having isolated the chromosomal species 2n=54 before the divergence of the three other species.DNA-DNA hybridization was also used to compare the Spalacinae (Eurasian mole rats), Murinae (Old World rats and mice), and Arvicolinae (voles and lemmings). These data enabled us to estimate the time of divergence of the spalacids at ca. 19 million years ago. The dates of divergence among the other rodent lineages, as predicted by DNA hybridization results, agree well with paleontological data. These dates of divergence are obtained by the relation between geological time and single-copy nuclear DNA change, a relation that was calibrated by Catzeflis et al. (1987) through the use of fossil Arvicolinae and Murinae data. 相似文献