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111.
A murine monoclonal antibody raised against hamster cauda epididymal spermatozoa was shown to recognize an Mr 34,000 component of epididymal epithelium. Antigen was localized by immunocytochemistry on the surface and in the apical cytoplasm of principal cells in the proximal corpus epididymidis but not in the caput or initial segment regions. Spermatozoa from the corpus epididymidis expressed antigen on their post-acrosomal plasma membrane and annulus. Epididymal principal cells from the proximal corpus region when cultured in vitro bound antibody on their apical surface for at least 5 days. Spermatozoa from the caput epididymidis co-cultured with epithelium expressed antigen after incubation for 8 and 24 h. These results suggest that a surface change to epididymal spermatozoa during maturation in vivo may also be elicited during in-vitro culture. 相似文献
112.
Exogenous Tryptophan Increases Synthesis, Storage, and Intraneuronal Metabolism of 5-Hydroxytryptamine in the Rat Hypothalamus 总被引:4,自引:2,他引:2
K. J. Lookingland N. J. Shannon D. S. Chapin K. E. Moore 《Journal of neurochemistry》1986,47(1):205-212
The effects of tryptophan administration on neurochemical estimates of synthesis [5-hydroxytryptophan (5-HTP) accumulation following administration of a decarboxylase inhibitor], storage [5-hydroxytryptamine (5-HT) concentrations], and metabolism [5-hydroxyindoleacetic acid (5-HIAA) concentrations] of 5-HT in selected regions of the hypothalamus were determined using HPLC coupled to an electrochemical detector. Tryptophan methyl ester HCl (30-300 mg/kg i.p.) produced a dose-dependent increase in the rate of 5-HTP accumulation throughout the hypothalamus but had no effect on the rate of accumulation of 3,4-dihydroxyphenylalanine. Peak 5-HTP levels were attained by 30 min following administration of tryptophan (100 mg/kg i.p.) and were maintained for an additional 60 min. Tryptophan also produced concomitant dose-dependent increases in 5-HT and 5-HIAA concentrations in these same regions without changes in the 5-HIAA/5-HT ratio. These results indicate that exogenous tryptophan administration selectively increases the synthesis, storage, and metabolism of 5-HT in the hypothalamus without altering the synthesis of catecholamines. Inhibition of 5-HT uptake with chlorimipramine or fluoxetine produced modest (10-40%) reductions in 5-HIAA concentrations throughout the hypothalamus, revealing that only a minor portion of 5-HIAA is derived from released and recaptured 5-HT, whereas the major portion of this metabolite reflects intraneuronal metabolism of unreleased 5-HT. In both chlorimipramine- and fluoxetine-treated rats, 5-HIAA concentrations were significantly increased by tryptophan administration, indicating that the increase in synthesis of 5-HT following precursor loading is accompanied by an increase in the intraneuronal metabolism of 5-HT. 相似文献
113.
Rajendra G. Mehta Leonard J. Schiff Steven J. Moore Ann Marie Buckley Marcia I. Dawson 《In vitro cellular & developmental biology. Plant》1986,22(3):164-168
Summary The mechanism of action of retinoid in reversing keratinization in hamster trachea is yet unknown. The purpose of this study
was to determine if cellular retinoic acid binding protein (CRABP) is present in tracheal epithelium following incubation
in serum-free, vitamin A-deficient culture medium for 10 days, and if the effectiveness of a retinoid in reversing keratinization
in organ culture is correlated with its ability to compete for CRABP sites. The cytosol prepared from tracheal cultures contained
CRABP at a concentration of 2.61 pmoles per mg protein. Of the four retinoids with carboxyl end group selected for the study,
two of the biological active retinoids competed for the CRABP sites. However, no correlation was observed between the biological
activity of the inactive retinoids and their ability to associate with the CRABP sites. These results indicate that even though
the action of retinoid may be mediated by retinoid binding protein, it cannot be used as a sole predicator of retinoid response
in hamster trachea.
This investigation was supported by Contract N01-CP-31012 and U. S. P. H. Grants CA30512 and CA32428, which were awarded by
the Division of Cancer Etiology, National Cancer Institute, DHHS.
Editor's Statement Tracheal organ cultures provide a useful model for the study of epithelial differentiation and carcinogenesis.
Much attention has been given to the action of retinoids in this process. Mehta et al. demonstrate a lack of correlation between
biological activity and specific cytosolic binding of members of this class of compounds, pointing out the need for a more
complete biochemical understanding of the mechanism of action and active forms of retinoids in this and other systems in vivo
and in vitro. David W. Barnes 相似文献
114.
Moore R 《American journal of botany》1985,72(5):733-736
Primary roots of Zea mays seedlings germinated and grown in 0.1 mM chloramphenicol (CMP) were significantly less graviresponsive than primary roots of seedlings germinated and grown in distilled water. Elongation rates of roots treated with CMP were significantly greater than those grown in distilled water. Caps of control and CMP-treated roots possessed extensive columella tissues comprised of cells containing numerous sedimented amyloplasts. These results indicate that the reduced graviresponsiveness of CMP-treated roots is not due to reduced rates of elongation, the absence of the presumed gravireceptors (i.e., amyloplasts in columella cells), or reduced amounts of columella tissue. These results are consistent with CMP altering the production and/or transport of effectors that mediate gravitropism. 相似文献
115.
A quantitative analysis of the relationship between pseudocopulatory behaviour and the ovarian cycle in the parthenogenetic lizard Cnemidophorus uniparens indicates (1) that this behaviour is frequently and regularly expressed by captive individuals, and (2) that the sexual role, either male-like or female-like, exhibited by an animal is correlated with its ovarian state. The expression of female-like behaviour patterns was associated with and primarily limited to the vitellogenic stage of the cycle. Male-like behaviour patterns occurred most frequently during post-ovulatory stages but was not limited to these stages. Neither behavioural role was ever expressed by non-reproductive individuals. Reproductive individuals often alternated in assuming the female-like and male-like roles during the progress of the ovarian cycle. These observations suggest that pseudosexual behaviour is hormonally activated in this species. However, it also appears that the prevailing social situation is an important factor determining which behavioural role is taken. This work strengthens the hypothesis that pseudosexual behaviour in all-female lizards occurs as the result of natural selection. 相似文献
116.
V J Merluzzi D M Savage M D Smith K Last-Barney R Mertelsmann M A Moore K Welte 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(3):1702-1706
Lymphokine-activated killer (LAK) cells are demonstrable within 2 wk after syngeneic or allogeneic (H-2-compatible) bone marrow transplantation in mice. Classical cytotoxic T lymphocytes (CTL) are not active until at least 4 wk after transplant. Both LAK cells and CTL bear the Thy-1 marker and do not possess the murine natural killer cell marker asialo GM. 相似文献
117.
S Y Wang H Castro-Malaspina M A Moore 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(2):1186-1193
We describe a liquid culture system allowing the long-term maintenance and differentiation of human marrow monocytes into well-developed, lipid-containing macrophages, and we show that these cells produce a regulating activity that enhances the colony formation induced by granulocyte-macrophage colony-stimulating factors (GM-CSF). Adherent, low density (less than 1.074 g/cm3) human marrow cells were used as a source of monocytic cells. Of 12 different culture conditions tested, alpha-medium supplemented with 20% horse serum and incubation at 37 degrees C provided the best conditions for macrophage development, adipogenesis, and long-term culture. Neither insulin (1 to 10 micrograms/ml) nor hydrocortisone (10(-6) M) improved the lipid accumulation in cultures containing horse serum. Trypsin was employed to remove fibroblasts without detaching monocytic cells from the marrow-derived adherent cell layers. Marked structural and functional changes characterized the transformation of monocytes into lipid-containing macrophages. Cell enlargement up to seven or eight times by 21 to 28 days of culture was associated with an increase in small and medium-sized lipid granules, as well as in acid phosphatase and nonspecific esterase activities. Ultrastructurally, there was an increase in the number of mitochondria, Golgi apparatus, lysosomes, rough endoplasmic reticulum, and lipid inclusions, which remained of small size and did not coalesce to form larger inclusions. The absolute quantity of Fc receptors, Ia antigens, and antigens recognized by monoclonal antibodies 61D3 and 63D3 also increased as a function of cell size. As marrow monocyte-macrophage differentiation proceeded, a rapid decline in GM-CSF production was accompanied by an increase in an activity that by itself had no capacity to stimulate colony formation in CFU-GM cultures devoid of GM-CSF, but did enhance the colony formation induced by optimal concentrations of GM-CSF. Neither the enhancing activity nor its production was related to the horse serum present in the culture supernatants. The morphology of colonies enhanced by this activity was different from the morphologic spectrum in non-enhanced cultures. This granulomonopoietic enhancing activity (GM-EA) represents another positive feedback regulator of hematopoiesis derived from cells of the monocyte-macrophage system. 相似文献
118.
An investigation of the regulation of specific anti-self responses was initiated with the development of an in vitro system in which spleen cells from NZB mice were stimulated by syngeneic mouse erythrocytes (MRBC) to produce MRBC-specific autoantibody-secreting cells. The response was measured by a modification of the focus-forming cell (FFC) assay, which enumerates cells secreting IgG, which specifically bind MRBC. Spleen cells from 9- to 12-mo-old NZB mice developed MRBC-specific FFC after 3 to 5 days in culture with MRBC. Few FFC were detected in the absence of MRBC in culture. Spleen cells from young (1- to 4-mo-old) NZB mice developed few if any FFC. Spleen cell populations containing T cells from young NZB mice suppressed this anti-MRBC response, whereas B cell populations from these young mice did not. In contrast, spleen cells, including T cell-enriched populations from old, Coombs'-positive mice were not capable under the same conditions of producing equivalent suppression of this in vitro autoimmune response. These data suggest that a population of suppressor T cells that may control the autoimmune anti-MRBC response in young NZB mice is lost, or else its activity is masked in old NZB mice that are actively producing anti-MRBC antibody. 相似文献
119.
The two accompanying papers describe the assignment of methyl-containing spin-systems in the 1H nuclear magnetic resonance spectra of tuna ferricytochrome c and tuna ferrocytochrome c. At present, 104 resonances from 208 C-H protons are assigned in both oxidation states. In this paper, the difference in chemical shift of a resonance between the two oxidation states is used together with a dipolar model of the unpaired electron spin of ferricytochrome c to compare the structure of cytochrome c in solution with three high-resolution structures of cytochrome c obtained by X-ray diffraction in single crystals. The overall protein fold and the positions of most of the haem-packing residues are shown to be invariant between the crystal and solution. However, three regions of the protein, at the C terminus, around the haem propionic acid groups and at the haem crevice near thioether-2, are found to undergo conformational changes on the removal of crystal packing constraints. 相似文献
120.
The acute administration of morphine to male rats decreased the rate of dopamine turnover in the median eminence and in the neural lobe of the pituitary, but was without effect in the intermediate lobe of the pituitary. Pretreatment with the opiate antagonist, naltrexone, reduced the effects of morphine. These results indicate that morphine, by acting on opiate receptors, inhibits the activity of tuberoinfundibular dopaminergic neurons that terminate in the median eminence and those tuberohypophysial dopaminergic neurons that terminate in the neural lobe of the pituitary. 相似文献