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41.
Summary Small intensely fluorescent (SIF) cells appeared singly or, more frequently, in variably-sized clusters in the sacroccygeal 8th and 9th sympathetic ganglia of the bullfrog. Smaller clusters containing only two to nine SIF cells accounted for 61% of 1773 clusters examined. The largest cluster contained 283 cells. The number of cells in individual ganglia also varied from 21 to 3332. SIF cells, solitary as well as in smaller clusters, received no distinct form of the synaptic contact. In contrast, the cells in larger clusters were frequently innervated by nerve endings that were similar in vesicular constitution to the nerve endings on principal ganglion (PG) cells. No synaptic contact was found between SIF cells and PG cells. SIF cells were also characterized by their location in the vicinity of blood capillaries with a continuous endothelium. p]Our observation seems to suggest that larger clusters of SIF cells receiving nerve endings are linked to a paracrine and/or endocrine system. Chemical influence via the blood stream and intraganglionic milieu for non-innervated SIF cells in the solitary or smaller clusters is a subject for speculation. An interneuronal role of SIF cells to relay stimuli to PG cells seems unlikely. The possible functions here assigned to SIF cells could be variable in efficiency depending on their population and density. 相似文献
42.
Kaoru Hatanaka Masami Imakita Soei Go Akira Yamamoto M.D. 《Cell and tissue research》1986,246(1):53-56
Summary A mast-cell activator, compound 48/80, causes proliferation of mesenchymal cells in the mesentery of rats. Its effect on W/W
vmice deficient in mast cells was tested to determine whether the proliferation is mediated in the degranulation of mast cells. Incorporation of [3H]thymidine into mesenchymal cells in the mesentery of these mice with or without compound 48/80 was very small compared to their normal litter mates. However, bone marrow transplantation markedly enhanced the effect of compound 48/80, and resulted in an incorporation of [3H]thymidine almost comparable to that observed in normal mice. Our results provide evidence that mesenchymal cell proliferation is caused by a product secreted by mast cells when stimulated by compound 48/80.Supported by a Grant-in-Aid for Scientific Research, No. 366, from the Japanese Ministry of Health and WelfareThe authors are indebted to Drs. Motomu Minamiyama and Yukio Hirata for valuable advices, and to Miss Mitsuko Inoue for technical assistance 相似文献
43.
Dr. Frederick Grinnell Akira Takashima Cheryl Lamke-Seymour 《Cell and tissue research》1986,246(1):13-21
Summary Human foreskin fibroblasts were used to reorganize hydrated collagen gels into a dermal-like matrix, after which freshly isolated keratinocytes isolated from rabbit ear skin were placed on the surfaces of the matrices and cultured for up to 12 days. Transmission electron microscopy revealed 8–12 cell layers of epidermal cells organized in three distinct strata. The basal stratum consisted of cuboidal to columnar cells with typical complement of organelles, oval nuclei, and prominent tonofilaments inserting into desmosomes. Mitotic cells often were found at this level. There was no well-defined basement membrane region; rather, many of the cells appeared to be in close contact with collagen fibrils. The intermediate stratum of suprabasal cells consisted of elongated cells that had reduced organelles, but still were connected to each other by desmosomes. Finally, the superficial stratum of suprabasal cells contained cells that were completely flattened and often appeared to be sloughing off the apical surfaces of the cultures. Indirect immunofluorescence studies carried out on frozen sections revealed bullous pemphigoid antigen associated with basal epidermal cells; pemphigus vulgaris antigen around the epidermal cells of all strata, and keratin present in the epidermal cells of all strata. Filaggrin was observed in punctate and fibrillar arrangements in suprabasal cells. Fibronectin was found in a linear deposit at the dermal-epidermal junction and around the fibroblasts in the reorganized collagen gels. Type-IV collagen and laminin, however, were not detected. 相似文献
44.
E coli ribosomes and rRNA's released 20 to 50 protons upon jump of magnesium ion concentration from 1 mM to 20 mM. The Mg2+-induced proton release was measured separately for 16S rRNA, 23S rRNA, 30S subunit, and 50S subunit by a new spectrophotometric method that had a much better sensitivity than the pH-stat method. The proton release from the subunits and rRNA's were similar in the number of protons, the pH dependence that had a minimum at neutral pH, and the upward concaveness of the Scatchard plot. From these results, the main source of protons in ribosomal subunits was assigned to nucleotide bases of rRNA's that showed a downward pKa shift upon Mg2+-ion binding. The subunits and rRNA's, however, differed in the proton release. 16S rRNA released protons somewhat more effectively than 23S rRNA, while 30S subunit released protons 2 to 5 times more effectively than 50S subunit. The marked difference between the two subunits suggest that ionizable bases in 16S and 23S rRNA's are covered and their pKa values are shifted by ribosomal proteins to different extents. The association of 30S and 50S subunits induced little proton release, showing that few ionizable groups with pKa near neutral pH are involved in the association. E. coli tRNA and poly U also showed Mg2+-induced proton release. The amounts of protons released from rRNA's, tRNA, and poly U were roughly proportional to the amount of bases not hydrogen bonded. The Mg2+-induced proton release from the natural and synthetic RNA's can be explained by the electrostatic field effect of polyphosphate backbones on bases not hydrogen bonded, as proposed in a previous paper. It also reflects the conformational structure of each RNA molecule. 相似文献
45.
Park Keun-Hyung; Fujisawa Sachiko; Sakurai Akira; Yamaguchi Isomaro; Takahashi Nobutaka 《Plant & cell physiology》1983,24(7):1241-1249
Endogenous gibberellins (GAs) in several kinds of crown gallcells and cultured cells derived from normal tissue of Nicotianatabacum were systematically analyzed by gas chromatography-selectedion current monitoring (GC-SICM) after chromatographic purifications,and GA1, GA9, GA19 and GA20 were identified. Agrobacterium tumefaciens,a pathogen of crown gall, was confirmed not to produce GAs inits culture. We also investigated endogenous GAs of mother plant,tobacco, and found the same kinds of GAs as in cultured cells.
3 Present address: College of Agriculture, Chonnam NationalUniversity, Kwangju 500, Korea. (Received May 19, 1982; Accepted July 22, 1983) 相似文献
46.
Rice root glutamate synthase activity was assayed with various reducing systems. Ferredoxin-dependent glutamate synthase (EC 1.4.7.1) and pyridine nucleotide-dependent glutamate synthase (NADH, EC 1.4.1.14; or NADPH, EC 1.4.1.13) exhibited a strict specificity for the electron donor. The ferredoxin-dependent glutamate synthase from rice roots could accept electrons from photoreduced ferredoxin in an illuminated reconstituted spinach chloroplast system. Thioredoxin, a potent electron carrier, was not able to provide either ferredoxin-dependent or pyridine nucleotide-dependent glutamate synthase with electrons as no glutamate formation was detected in the presence of reduced thioredoxin f or m. 相似文献
47.
Ichiro Oohara Akira Suyama Akiyoshi Wada 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1983,741(3)
Poly(l-glutamic acid) has been reported to mediate in vitro nucleosome assembly (Stein, A., Whitlock, J.P., Jr. and Bina, M. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 5000–5004). To study the reaction mechanism, we have reconstituted nucleosome core particles from chicken erythrocyte core DNA and core histones in the presence of poly(l-glutamic acid) and analyzed the assembly products by polyacrylamide gel electrophoresis. Poly(l-glutamic acid), which binds and forms a large complex with core histones, is replaced with core DNA in the reconstitution process. When histone-poly(l-glutamic acid) complex and core DNA are mixed with a histone:DNA ratio of 1.0, the yield of core particles increases by prolonged reconstitution time. Two phases with a distinct time range appear in the process. In the fast phase within 30 min, 60% of the DNA is involved in products containing histones: reconstituted core particles, a larger nucleoprotein complex and aggregation. In the second phase, the remaining DNA and the DNA in the aggregation decrease, and the core particles increase slowly. The yield of core particles is approx. 60% after 24 h. The slow phase is not observed by reconstitution with a histone:DNA ratio of 2.0 in the initial mixture. The reaction scheme of the assembly process derived from these data is given. Based on the in vitro reaction scheme, the possible role of in vivo ‘nucleosome assembly factors’ is also discussed. 相似文献
48.
Kunio Yamato I-Yih Huang Helmut Muensch Akira Yoshida Heinz-Werner Goedde Dharam P. Agarwal 《Biochemical genetics》1983,21(1-2):135-145
The usualE 1 u and atypicalE 1 a human pseudocholinesterases (acylocholine acylhydrolase, EC 3.1.1.8) were purified to homogeneity. The active-site serine residue was conjugated with diisopropyl fluorophosphate and digested with trypsin. The tryptic peptide containing the active site was isolated by gel filtration followed by two-dimensional paper chromatography and electrophoresis. The amino acid sequence of the active site peptide obtained from the usualE 1 u enzyme was found to be Gly-Glu-Ser-Ala-Gly-Ala-Ser-Ala-Val-Ser-Leu. A remarkable structural homology exists between the human and the horse enzymes in their active sites. From the difference in electrophoretic mobility of the active-site peptides obtained from the usual and atypical enzymes, the probable structure of the atypical human enzyme was deduced as Gly-His-Ser-Ala-Gly-Ala-Ser-Ala-Val-Ser-Leu. 相似文献
49.
Separation of the Polypeptides of Chlamydia and Its Cell Walls by Polyacrylamide Gel Electrophoresis 总被引:6,自引:3,他引:3 下载免费PDF全文
The polypeptide composition of Chlamydia was examined by acrylamide gel electrophoresis. When the polypeptide patterns of purified infectious elementary bodies (EB) of C. psittaci meningopneumonitis strain, 6BC strain, and C. trachomatis T'ang strain were compared, no significant differences were observed. The polypeptide patterns of whole EB and reticulate bodies (RB) appeared to overlap, but differences were found. In EB cell walls, nine main and several minor bands of polypeptides were observed in gels containing sodium lauryl sulfate, and the eighth main band from the top of the gel stained positive with periodic acid-Schiff reagent. On the other hand, the polypeptides in bands 3, 6, and 8 in EB cell walls were missing or minor in RB cell walls, and the ninth band was clearly stained by PAS. Band 8 was also stained slightly. Purified subunits, which occur as a lattice structure on the inside layer of EB cell walls but are largely missing in RB cell walls, contained bands 4, 6, and 8, and band 8 was PAS positive. These results indicate that significant polypeptide synthesis or reorganization in the cell walls occurs during the growth cycle. 相似文献
50.
Dielectric constant and dielectric loss of heavy meromyosin (HMM) were measured with varying pH. HMM showed a broader dispersion pattern than that with a single relaxation time especially on the high-frequencey side. The dielectric increment increased sharply with pH, above pH 6, whereas the mean relaxation time and whole dispersion pattern were unchanged in the same region. The values of the increment and the mean relaxation time were much larger than those of usual globular proteins. The dispersion profile, pH dependence, and values of the increment are well explained by Oosawa's counterion fluctuation theory. Other mechanisms are more or less inadequate to our results. In the low pH region below the isoelectric precipitation region, both the increment and the mean relaxation time decreased; this is probably due to partial denaturation and suppression of the dissociation of carboxyl groups. An experiment on a urea-denatured sample supports this assumption. The biological significance of the pH dependence is discussed. 相似文献