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21.
Active uptake of a labelled nonmetabolizable amino acid, alpha-aminoisobutyric acid (AIB), into isolated superior cervical sympathetic ganglia (SCG) excised from adult rats was considerably stimulated by the addition of either norepinephrine (NE, 50 microM) or 3,4-dihydroxyphenylethylamine (dopamine, DA, 100 microM) to the medium during aerobic incubation for 2 h at 37 degrees C. The NE-induced increase in AIB uptake was significantly antagonized by the addition of an alpha 1-adrenoceptor antagonist (prazosin, 10 microM) in SCG axotomized 1 week prior to the examination, in which most of the ganglionic neurons had degenerated and reactive proliferation of the satellite glial components was in progress. The addition of neither acetylcholine (ACh, 1 mM) plus eserine (0.1 mM) nor cyclic nucleotides (1 mM) changed the AIB uptake by the SCG. In the axotomized SCG, the NE-evoked increase in AIB uptake was much more pronounced than that of intact or denervated SCG. A kinetic study of the active AIB uptake in the SCG showed that NE produced a decrease of the Km value and an increase in the Vmax, especially in the axotomized SCG. Ganglionic Na+, K+-ATPase activity was greatly stimulated in the presence of NE, but not by ACh. These results strongly suggest that the NE-induced enhancement of active AIB uptake in the isolated SCG is occurring in glial cells rather than in neuronal cells, with a possible alteration of membrane properties for amino acid uptake and with an apparent regulation by the stimulated transport enzyme Na+, K+-ATPase. 相似文献
22.
Noritsugu Yabe Yutaka Matsuya Isao Yamane Mitsuru Takada 《In vitro cellular & developmental biology. Plant》1986,22(7):363-368
Summary A newly developed, serum-free medium (NYSF-404) selects for antibody-producing hybridomas after fusion of antigen-sensitized
mouse spleen cells with myeloma cell lines P3-X63-Ag8-U1 (P3-U1), P3-X63-Ag8-6.5.3 (Ag8.653), or P3-NSI/1-Ag4-1 (NS-1). Without
the need for hypoxanthine-aminopterinthymidine (HAT) selection of hybrid cells, frequency of hybridoma formation in medium
NYSF-404 is higher (twice) than that in serum- and HAT-containing medium. Colonies developed upon limiting dilution in the
presence of the mortal parent myeloma cells in medium NYSF-404 and pure culture of antibody-secreting cells could be subsequently
established. The results suggest that fusions can be done in serum-free medium and that the clonal growth of hybridomas is
dependent on factors produced by parent myeloma cells under serum-free culture conditions. Such factors seem deficient in
serum- and HAT-containing medium or are masked by serum. 相似文献
23.
Chromosomal localization of the Epstein-Barr virus (EBV) genome in Bloom's syndrome B-lymphoblastoid cell lines transformed with EBV 总被引:3,自引:0,他引:3
The localization of the Epstein-Barr virus (EBV) genome in chromosomes of human B-lymphoblastoid cell lines (LCLs) transformed with EBV, and the effect of EBV DNA on the level of sister chromatid exchange (SCE) in Bloom's syndrome (BS) B-LCLs, were examined with chromosomal in situ hybridization techniques using a 3H-EBV DNA probe. EBV DNA was detected in chromosomes 1–5 and 13–15 at specific G band regions in BS as well as in normal B-LCLs, regardless of SCE. Several chromosomal sites (1p31, 1q31, 4q22–24, 5q21, 13q21, 14q21) carrying EBV DNA seemed to be very characteristic in normal as well as in BS B-LCLs. There was no statistically significant difference in silver grain counts due to EBV DNA and their distribution in different chromosomes or groups among normal and BS B-LCLs with normal and high SCE. These findings strongly indicate that EBV infection did not introduce a correcting factor for BS SCE. 相似文献
24.
It seems established that under pathological conditions, microglia and blood monocytes (invading the cerebral parenchyma) behave as histiocytic cells in the central nervous system. However, it has not been clear whether or not phagocytic cells are present in normal cerebral tissue. Recently, we found a new type of cell having an uptake capacity for exogenous substance at the bifurcations of small cerebral vessels except for capillaries. According to Imamoto et al. (1982), ameboid microglia, a kind of precursor of microglia, appear at a perinatal stage and can incorporate exogenous material. In the present paper, the developmental sequences of ameboid microglia and the unique cells laden with fluorescent granules are compared at a light and electron-microscopic level. From this study, it is clear that ameboid microglia are already present in the corpus callosum at 5 days after birth and are potent in their uptake capacity for horseradish peroxidase (HRP). However, at 2 weeks, they transform into star cells and the capacity for incorporation diminishes markedly. The finding is also supported by the quantitative analysis of transformation of ameboid microglia. At 3 months, glial cells do not take the administered HRP under the present conditions. On the other hand, fluorescent granular perithelial (FGP) cells arise from a leptomeningeal tissue (pia mater) and become situated in the perivascular spaces. They are not clearly defined at 5 days, and their uptake capacity for HRP has not yet developed. At 2 weeks, the FGP cells take definite forms with several inclusion bodies, and their uptake capacity for HRP attains a certain degree. Often, they are located at bifurcations of small blood vessels. At 3 months, the FGP cells differentiate completely in appearance, and their pinocytotic capacity reaches a high level. Consequently, the FGP cells belong to a different type of cell from that of ameboid microglia in their developmental sequences and assume a principal role of scavenging waste products in normal cerebral tissue. 相似文献
25.
Relative effectiveness and interaction of ultraviolet-B, red and blue light in anthocyanin synthesis of apple fruit 总被引:3,自引:0,他引:3
The effect of light on anthocyanin production in apple ( Malus pumila Mill. cv. Jonathan) skin disks was investigated, with prolonged irradiation from different light sources. High fluence rates of white light provided from a xenon lamp were unable to produce large amounts of anthocyanin, and anthocyanin production became saturated at about 30 W m−2 . When UV-B light, provided by a fluorescent lamp which had an emission peak at 312 nm, was combined with the white light, anthocyanin production was synergistically stimulated and increased up to the highest fluence rates of white light tested (44 W m−2 ). This UV-B light was more effective than red and blue light provided from fluorescent lamps, but anthocyanin production became saturated at about 1.7 W m−2 . However, simultaneous irradiation with red and UV-B light had a synergistic effect. UV-B light was also effective in increasing anthocyanin production in whole fruit. Therefore this synergism seemed to have an important role in the development of the desirable red skin color under field light conditions. The results of aminoethoxyvinylglycine treatment suggested that ethylene was not involved in the stimulative effect of UV-B light. 相似文献
26.
Susumu Wakabayashi Yumi Magae Yutaka Kashiwagi Takashi Sasaki 《Applied microbiology and biotechnology》1985,21(5):328-330
Summary When purified protoplasts of Pleurotus cornucopiae IFO9614 were incubated with a mixture of cell wall lytic enzymes, they were found to increase their size. Their average diameter increased from 4.3 m to 31 m after 65 h incubation at 24° C. The presence of cellulase ONOZUKARS in the enzyme mixture had a significant effect on the formation of giant protoplasts. Regeneration frequency of giant protoplasts in a medium containing 0.5 M sucrose was 3.5%, approximately six times that of normal protoplasts. 相似文献
27.
Yoshinobu Shioda Hiroshi Nagura Yutaka Tsutsumi Kazuo Shimamura Norikazu Tamaoki 《The Histochemical journal》1984,16(8):843-854
Summary Leu 7 immunoreactivity was demonstrated with the indirect peroxidase-labelled antibody method on frozen and paraffin-embedded tissue sections of human digestive organs. Anti-Leu 7 monoclonal antibody, which allegedly detects mononuclear cells with natural killer or killer activity, recognized lymphoid cells among intestinal epithelial cells and in the germinal centres of solitary lymphoid follicles of small and large intestine, and a few in gallbladder, liver and the lamina propria of the intestine. In addition, peripheral nerve fibres, endocrine cells in the gut and pancreas and carcinoid and islet cell tumours were also positively stained. At the ultrastructural level, Leu 7 antigen was localized on the plasma membrane of granulated lymphoid cells in the gut mucosa and on the secretory granules of intestinal endocrine cells. In normal pancreas, Leu 7 immunoreactivity was demonstrated in most cells containing pancreatic polypeptide and in many cells containing somatostatin or glicentin. Insulin-containing cells, however, lacked Leu 7 immunoreactant. These findings were obtained in both frozen sections and paraffin-embedded sections. The possible cross-reactivities of monoclonal antibodies are discussed as they raise an important caveat in immunohistochemical studies using these antibodies. 相似文献
28.
Yutaka Tamaura Katsunobu Takahashi Yoh Kodera Yuji Saito Yuji Inada 《Biotechnology letters》1986,8(12):877-880
Summary A ferromagnetic modifier was prepared by reacting ferrous(Fe2+)- and ferric(Fe3+)-ions with polyethylene glycol having two carboxyl groups (MW:2000) at pH 8.0–8.5. Lipase fromPseudomonas
fragi 22–39B was coupled with the modifier using water-soluble carbodiimide. The modified lipase, which was dispersed into buffered solutions in the size range of 30–70 nm, exerted the hydrolytic activity of 8.0 U/mg. In a magnetic field of 250 Oe, the ferromagnetic-modified lipase was readily recovered from the colloidal solution. 相似文献
29.
Diazepam action onγ-aminobutyric acid-activated chloride currents in internally perfused frog sensory neurons 总被引:3,自引:0,他引:3
The Cl- current (ICl) in gamma-aminobutyric acid (GABA)-sensitive frog sensory neuron was separated from other Na+, Ca2+, and K+ currents using a suction pipette technique which allows internal perfusion under a single-electrode voltage clamp. Diazepam (DZP) itself evoked no response but facilitated the dose- and time-dependently GABA-induced ICl without changing the GABA equilibrium potential (EGABA) at concentrations ranging widely, from 3 X 10(-9) to 10(-4) M. In the presence of DZP, the GABA dose-response curve shifted to the left without changing the maximum current, indicating that DZP modifies the interaction between GABA and its receptor rather than affecting directly the channel activation step. The enhancement of the GABA-induced ICl by DZP depended neither on the membrane voltage nor on the inward or outward direction of the ICl. DZP also potentiated the ICl elicited by GABA agonists such as beta-alanine, taurine, homotaurine, 5-aminovaleric acid, l-GABOB, d-GABOB, glycine, and muscimol. The GABA response enhanced by pentobarbital (PB) was further enhanced by adding DZP, indicating that DZP and PB do not act in the same way. Ro5-3663, a diazepam analogue, enhanced the GABA-induced ICl only in a narrow range of the concentrations but inhibited the current at concentrations higher than 2 X 10(-6) M. 相似文献
30.
Summary Monoaminergic nerve fibers were studied in the pineal organ of the monkey, Macaca fuscata, by use of fluorescence and immunohistochemical procedures. Abundant formations of noradrenergic nerve fibers were observed in the pineal organ. They entered the parenchyma in the form of several coarse bundles via the capsule in the distal portion of the organ and spread throughout the organ after branching into smaller units. The density of the autonomic innervation decreased gradually toward the proximal portion of the organ. In the distal portion, numerous nerve fibers formed perivascular plexuses around the blood vessels and some fibers ran as bundles unrelated to the blood vessels in the stroma. Fine varicose fibers and bundles derived from these plexuses penetrated among the pinealocytes. However, only a few intraparenchymal fluorescent fibers were detected in the proximal third of the gland. With the use of serotonin antiserum serotonin-immunoreactive nerve fibers were clearly restricted to the ventroproximal part of the pineal organ. Although the somata of the pinealocytes showed intense immunoreactivity, their processes were not stained. In one exceptional case, clusters of pinealocytes displaying very intense immunoreactivity were found in an area extending from the distal margin of the ventral portion of the pineal stalk to the proximal portion of the pineal organ proper; these cells were bipolar or multipolar and endowed with well-stained processes. 相似文献