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91.
Interferon synthesis in the early post-implantation mouse embryo 总被引:6,自引:0,他引:6
Denise P. Barlow Beverley J. Randle Derek C. Burke 《Differentiation; research in biological diversity》1984,27(1-3):229-235
Abstract. A qualitative bioassay was adapted and used to determine the ability of the early post-implantation mouse embryo to synthesise interferon. Interferon production was not seen in any embryo tissue in the absence of an inducer and could only be detected in virus-induced tissue from the early 7th day of development. This induced interferon synthesis was initially confined to the trophoblast of the early 7th day embryo. It was then found in tissues of both trophoblast and inner cell mass origin in the early 8th day, and subsequently, in derivatives of the embryonic ectoderm in the 13th-day embryo. 相似文献
92.
Summary Various cell types of the rat testis during pubescence, including germ, Sertoli, and Leydig cells, were partially enriched. The fractions were tested for the presence, binding, and secretion of H-Y antigen. The main results are: Immature germ cells are H-Y antigen-negative until the late diploid stages, and late primary spermatocytes or spermatids become positive; the somatic cells of the gonad are positive at all ages examined (18 days old to adulthood). Secretion of H-Y antigen is restricted to the Sertoli cell fraction. Binding of externally supplied antigen takes place on Leydig cells; the Sertoli cell surface will be saturated because of active secretion; there is no binding to germ cells. Thus, immature germ cells seem to be the only H-Y antigen-negative cells of the male organism, and the Sertoli cells seem to be the only ones to secrete H-Y antigen. 相似文献
93.
94.
We surveyed a French male population for the incidence of missing or reduced upper lateral incisors (ULI). In 5,738 subjects, we observed an incidence of 1.59% with one or two reduced ULI (the other normal) and 1.90% with one or two missing ULI (the other normal or reduced), altogether, 3.49% affected subjects. Furthermore, 250 random controls were observed. Agenesis of other teeth is more frequent in propositi. Missing third molars were 12.4% in controls, 24.0% in propositi with reduced ULI and 39.6% in propositi with two missing ULI. Furthermore, agenesis of incisors, canines and premolars ranges from 0.4% in controls to 1.3% in propositi having reduced ULI and 5.0% in propositi with two missing ULI. So, propositi with reduced ULI are intermediate between the controls and the propositi with missing ULI with respect to the frequency of agenesis of other teeth. On the other hand, a different ranking is observed with respect to the teeth measurements: reduction of tooth size is more marked in propositi with reduced ULI than in propositi with missing ULI. The reduction mainly affects canines, incisors and to a lesser degree, premolars. Arch length and interpremolar diameters are smaller in propositi with missing ULI, compared with controls. 相似文献
95.
Hans-Jörg Jacobsen 《Physiologia plantarum》1982,56(2):161-167
Auxin-binding proteins, have been identified in the soluble cytoplasrnic protein fraction of etiolated pea epicotyls, Pisum sativum L., cv. "Dippes Gelbe Victoria". The binding is specific for the auxins NAA, IAA and 2,4-D with a KD in the range of 0.1–0.4 μ M . Moreover, the binding is competitive, sensitive to digestion by proteinase and shows linearity with the protein content of the assay mixture. The binding proteins appear to be very labile, since repeated freezing and thawing destroys specific binding. No clear pH-optimum could be detected in the physiological pH-range 5.5–8.0, but the binding was doubled at pH 8.0 compared to pH 5.5–7.0. 相似文献
96.
The subcellular site of -amylase (EC 1.6.2.1) synthesis and transport was studied in barley aleurone layers incubated in the presence or absence of gibberellic acid (GA3). Using [35S]methionine as a marker, the site of amino-acid incorporation into organelles isolated from aleurone layers incubated with and without GA3 was determined following purification by isopycnic sucrose-density-gradient centrifugation. Incorporation of radioactivity into trichloroacetic-acid-insoluble proteins was greatest in those fractions exhibiting activity of an endoplasmic reticulum (ER) marker enzyme. Further fractionation of densitygradient fractions by sodium-dodecyl-sulfate polyacrylamide-gel electrophoresis showed that a major portion of the radioactivity in the ER fractions was present in a protein co-migrating with marker -amylase. This protein was identified as authentic -amylase by immunoadsorbent chromatography and affinity chromatography. The newly synthesized -amylase associated with the ER was shown to be sequenstered within the lumen of the ER by experiments which showed that the enzyme was resistant to proteolytic degradation. The labelled -amylase sequestered in the ER can be chased from this organelle when tissue is incubated in unlabelled methionine following a 1-h pulse of labelled methionine. The isoenzymic forms of -amylase found in tissue homogenates and incubation media of aleurone layers incubated with and without GA3 were characterized after chromatography on diethylaminoethyl cellulose. In homogenates of GA3-treated aleurone layers, five peaks of -amylase activity were detected, while in homogenates of aleurone layers incubated with-out GA3 only three peaks of activity were found. In incubation media, four isoenzymes were found after GA3 treatment and two were found after incubation without GA3. We conclude that at least five -amylase isoenzymes are synthesized by the ER of barley aleurone layers and that this membrane system is involved in the sequestration and transport of four of these isoenzymes.Abbreviations CHA
cyclohepataamylose
- DEAE-cellulose
diethylaminoethyl-cellulose
- ER
endoplasmic reticulum
- GA3
gibberellic acid
- SDS-PAGE
sodium-dodecyl-sulfate polyacrylamide-gel electrophoresis 相似文献
97.
Germination of celery seed occurred after 6 d of imbibition in light. During this time the embryo enlarged at the expense of the adjacent endosperm cells and at the time of germination was 2–3 times as long as in the dry seed. Breakdown of the endosperm cells near the root cap preceeded radicle emergence. None of these changes occurred in darkness.Endosperm digestion began adjacent to the embryo and spread radially. In degrading cells, the aleurone grains often became larger and fewer in number. The cell walls were modified and appeared to undergo partial degradation. Ultimately the cells seemed to lose their contents. In cells adjacent to the root cap, similar changes occurred except there was a transient appearance of starch grains. Radial progression of endosperm breakdown also occurred in isolated endosperm treated with gibberellin A4+7.The results indicate that (1) the stimulus for breakdown of celery endosperm emanates from the embryo in response to light; (2) the stimulus may be a gibberellin because changes in endosperm cells and the sequence of endosperm digestion during germination resemble the responses of isolated endosperm to gibberellin; and (3) the radial progression of endosperm breakdown during germination may be the result of a sequential response of cells to a uniformly applied stimulus rather than the result of gradual embryo expansion. 相似文献
98.
Christiane Guguen-Guillouzo Marie-France Szanjnert Denise Glaiser Claudine Gregori Fanny Schapira 《In vitro cellular & developmental biology. Plant》1981,17(5):369-377
Summary Aldolase and pyruvate kinase isozymes were investigated in cultured hepatocytes from fetal, regenerating, and 2-acetyl-aminofluorene-fed
rat liver as well as in some epithelial liver cell lines. Our results show that: (a) cell proliferation and prolonged expression
of specific isozymes were found only in cultured hepatocytes from 17-day old fetuses; (b) the fetal type of pyruvate kinase
expressed in regenerating and carcinogen-treated liver was temporarily lost only in cultured hepatocytes from regenerating
liver; (c) the adult type of aldolase and pyruvate kinase was absent in one epithelial cell line derived from a carcinogen-treated
liver and in the hepatoma tissue cell (HTC) line but was found in the Faza clone of the Reuber H35 cell line during the 50 first passages in vitro; and (d) the isozyme pattern of pyruvate kinase was always more strongly
shifted than that of aldolase.
The observations suggest that: (a) hepatocytes from carcinogen-treated liver exhibit the same lack of ability to proliferate
in primary culture as normal adult hepatocytes; (b) adult hepatocytes can produce fetal isozymes without prior cell division;
(c) pyruvate kinase is a stronger marker of dedifferentiation (retrodifferentiation) than aldolase; and (d) regulatory processes
of isozyme expression are different during ontogenesis, regeneration, and hepatocarcinogenesis.
This work was supported by the “Institut National de la Santé et de la Recherche Médicale” and the “Fondation pour la Recherche
Medicale Fran?aise” 相似文献
99.
E. Jacobsen 《Plant Cell, Tissue and Organ Culture》1981,1(1):77-84
Cytological studies on leaf callus cells and regenerated potato plants suggest that it may be possible to utilize somatic
chromosome doubling to obtain tetraploids from outstanding dihaploid breeding clones. The ploidy levels found in callus-derived
plants were diploid, tetraploid, and octaploid, but the proportion of these was dependent on the donor genotype. L1 and L3 germ layers were studied in more than 300 plants; periclinal ploidy chimerism, an undesirable feature of colchicine doubling,
was not found.
Leaf callus was more efficiently induced using NAA than 2, 4-D as an auxin source in the Murashige and Skoog medium. A high
proportion of dividing cells in young calli were polyploid. The frequency of doubled and octaploid plants regenerated was
significantly dependent on donor genotype. The extent of polyploidization was marginally higher after callus growth on a medium
containing 2, 4-D than in a medium containing NAA. In some genotypes the chromosome numbers of regenerated plants were variable,
being less than tetraploid (mixohypotetraploid). After tuber propagation, the original ploidy level was maintained although
mixohypotetraploidy persisted.
In a few somatically doubled clones, male fertility was tested and found to be satisfactory with respect to seed-setting. 相似文献
100.
C-glycosylflavone accumulation in Sandoz 6706-treated barley seedlings is a photocontrolled response
Sandoz 6706 pretreatment of white light grown barley seedlings causes a 60% increase in saponarin (6-C-glucosyl-7-O-glucosylapigenin) but a 300% increase in lutonarin (3′-hydroxysaponarin). Norflurazon has little effect on saponarin levels but is almost as effective as Sandoz 6706 in enhancing lutonarin net synthesis. Barley roots contain saponarin and lutonarin only after herbicide treatment. Mung bean seedlings respond to Sandoz 6706 by accumulating higher levels of rutin and delphinidin 3-glucoside. The results are discussed in relation to the site of action of the herbicides, the High Energy photoresponse, and control of flavonoid 3′-hydroxylation. 相似文献