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Summary Cellular and subcellular distribution of iron in the lamina propria of rat duodenum was studied after a single i.p. injection of iron dextran, using electron microscopy and peroxidase cytochemistry. X-ray spectrum microanalysis was used for positive identification of iron. Ironcontaining particles (IP) were found in the cytoplasm of three cell types, viz. macrophages, pericytic reticular cells and sheathing fibrocytes. IP-containing organelles in lamina propria cells were more heterogeneous compared to absorptive cells and, in addition, some differences were noted in the subcellular distribution of IP in the 3 cell types. A common denominator in these 3 cell types was the presence of endogenous peroxidase, also shared by Kupffer cells which are known to be involved in iron storage. Peroxidase activity was absent in absorptive epithelial cells. It is hypothesized that the cells of the lamina propria, like Kupffer cells, may be the site of storage of excess iron absorbed, releasing iron upon demand and migrating into the lumen to prevent iron overload. In this fashion they may regulate the exchange of iron with the environment. The presence of peroxidase in these as well as Kupffer cells, and its absence in absorptive cells also raises the possibility that this enzyme may be related to certain aspects of iron storing process. 相似文献
124.
Nine representative pairs of heterothallic (=self-sterile, cross-fertile) strains of theClosterium peracerosum-strigosum-littorale complex from the northern Kanto area in Japan have been studied under the defined standard culture conditions. Since a wall
thickening at cell apices was observed in vegetative cells of all the strains, these strains turned out to belong to the morphological
group II (Ichimura and Watanabe, 1976). The result of statistical analyses of their cell size variations corresponded well
with the result of intercrossing experiments between them. It was shown that these strains are virtually composed of three
biologically different groups which are morphologically distinct and reproductively isolated completely or at least partially
from each other. For convenience, these three groups have been designated as II-A, II-B, and II-C in the order of from smaller
to larger cell size. In intra-group crossings, a large number of zygospores were formed, and they germinated well to yield
healthy populations of their progenies in all the three groups. In inter-group crossings, no sign of sexual reproduction was
observed between Group II-A and Group II-C or Group II-B and Group II-C, and a marked decrease of zygospore formation was
observed between Group II-A and Group II-B, especially between Group II-A minus and Group II-B plus. It was concluded that
the distinctions between the three groups are biologically sound and that each represents an evolutionary unit.
This paper represents a portion of a thesis submitted to the faculty of the Graduate School of Hokkaido University by the
senior author in partial fulfillment of the requirements for the degree of Doctor of Science.
This study was supported by the Grants in Aid, No. 174233 & No. 034036, from the Scientic Research Fund of the Ministry of
Education, Japan. 相似文献
125.
Hana Dolezalova Matej Stepita-Klauco Jan Kucera Hideyuki Uchimura Makoto Hirano 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1978,146(1):67-76
Concentrations of cadaverine, monoacetylcadaverine and monopropionylcadaverine in the blood of schizophrenic and nonschizophrenic subjects were measured. Two groups, one from the U.S.A. the other from Japan, were tested. Monoacetylcadaverine and monopropionylcadaverine were found elevated in the blood of some schizophrenic patients in comparison with those in controls in each group. Their increase could be caused by a reduced monoamine oxidase activity or by an increased acylation in schizophrenic patients. 相似文献
126.
127.
Sodium- and potassium-activated adenosinetriphosphatase (Na+, K+-ATPase) purified from dog kidney outer medulla was examined by polyacrylamide gel electrophoresis and by photoaffinity labeling with N-(ouabain)-N'-(2-nitro-4-azidophenyl)-ethylenediamine (NAP-ouabain). The large subunit band (alpha-band) split into two bands on the gel after the enzyme was heat-treated in the presence of 1% sodium dodecylsulfate (SDS). Of the two bands (alpha I and alpha II), alpha I had the same electrophoretic mobility as the original band, while alpha II moved slightly faster. Total conversion into alpha II was not observed, about half of the original remaining as alpha I. Below 60 degree C, heat treatment did not produce alpha II. Phenylmethylsulfonyl fluoride did not prevent the appearance of alpha II. Both alpha I and alpha II were labeled with [3H]NAP-ouabain. Nonspecific incorporation of [3H]NAP-ouabain also occurred irrespective of illumination, but it was removed either by diffusion during staining and destaining of the gel or by treatment of the enzyme with trichloroacetic acid. It is tentatively concluded that the splitting of the band reflects some intrinsic differences in situ of the alpha-subunit of dog kidney membrane Na+,K+-ATPase. 相似文献
128.
M Nagano H Ishibashi V McCully G L Cottam 《Archives of biochemistry and biophysics》1980,203(1):271-281
Incubation of rat liver parenchymal cells with 10?5m epinephrine or norepinephrine resulted in a rapid incorporation of 32P into pyruvate kinase. Inclusion of α-adrenergic blocking agents (phenoxybenzamine or phentolamine) in the hepatocyte incubation medium prior to addition of epinephrine suppressed the subsequent phosphorylation of pyruvate kinase. On the other hand, inclusion of the β-adrenergic antagonist, propranolol, in the hepatocyte incubation medium prior to addition of epinephrine did not suppress the epinephrine-elicited phosphorylation of pyruvate kinase. Exogenous addition of either cyclic AMP or cyclic GMP to the hepatocyte incubation medium also resulted in increased phosphorylation of pyruvate kinase. To investigate whether the same amino acid residue(s) of liver pyruvate kinase was being phosphorylated in each instance, 32P-labeled pyruvate kinase was isolated from hepatocytes after incubation in the presence or absence of either glucagon or epinephrine. In addition, purified liver pyruvate kinase was phosphorylated in vitro with a rat liver cyclic AMP-dependent protein kinase. Each 32P-labeled pyruvate kinase was then subjected to tryptic digestion, two-dimensional thin-layer peptide mapping, and autoradiography. Each 32P-labeled pyruvate kinase sample yielded 44 to 48 tryptic peptides upon staining with ninhydrin and 4 peptides that contain 32P as detected by autoradiography. Furthermore, the same 4 peptides of pyruvate kinase were radiolabeled in each instance. Thus phosphorylation of pyruvate kinase in vitro with [γ-32P]ATP or upon addition of either glucagon or epinephrine to hepatocytes incubated with 32Pi resulted in phosphorylation of the same amino acid residues. 相似文献
129.
When thiamine concentration in subculture medium was rapidlylowered to nil, soybean cells in suspension became necroticand stopped growing entirely. When it was gradually lowered,cell growth was vigorous until the concentration was reducedto 7.8?103 mg/liter. The cells at this level of thiamineceased growing for a time, but prolonged culture in the samemedium resulted in the appearance of fresh white cells whichcould be easily distinguished from the old brown, necrotic cellsin the aggregates. These new cell lines could be subculturedwith further reduction in the thiamine supply, growing as largeraggregates of about 4 mm in diameter. New cell lines were similarly obtained by prolonged culturesin media containing a thiamine precursor; three lines appearedto be habituated to the pyrimidine moiety and one to the thiazolemoiety. The latter cell line could be subcultured without thiamineand its precursors for at least eight passages. These habituatedcells were characterized by the increase of the dry to freshweight ratio and by their growth in large aggregates.
1Present address: Section of Phytochemical Research, Eisai Co.,Ltd., Kawashima, Gifu 483, Japan. (Received December 15, 1978; ) 相似文献
130.
On the basis of recent neurophysiological findings on the mammalian visual cortex, a selforganizing neural network model is proposed for the understanding of the development of complex cells. The model is composed of two kinds of connections from LGN cells to a complex cell. One is direct excitatory connections and the other is indirect inhibitory connections via simple cells. Inhibitory synapses between simple cells and complex cells are assumed to be modifiable. The model was simulated on a computer to confirm its behavior. 相似文献