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971.
Joe E. Springer Robert L. Isaacson Jeanne P. Ryan John H. Hannigan 《Life sciences》1983,33(3):207-211
Animals were pretreated with 6-OHDA or ascorbate vehicle injected into the nucleus accumbens and tested 10 days later for excessive grooming induced by intracerebroventricular injection of ACTH1–24. The animals pretreated with 6-OHDA showed a significant decrease in excessive grooming produced by the neuropeptide and this reduction was seen only in the last 30 minutes of a 60-min test session. The results suggest an interaction of ACTH with dopamine systems on the onset and maintenance of excessive grooming. 相似文献
972.
Differential Effects of Fluoronorepinephrines on Phosphatidylinositol Turnover in Rat Pinealocytes 总被引:2,自引:2,他引:0
(+/-)-Norepinephrines (NAs), substituted with fluorine at positions 2, 5, and 6 of the ring, were compared with the unsubstituted compound with respect to their capacity for eliciting increased incorporation of [32P]orthophosphate into phosphatidylinositol of pinealocytes. 5F-NA and 6F-NA were approximately equipotent with NA, whereas 2F-NA required a higher concentration and gave lower maximum stimulation. Inhibition of these effects by prazosin confirmed the participation of alpha 1-adrenergic receptors. The results are comparable with those reported for alpha 1-adrenergic receptor-mediated events in other systems and different from the beta-adrenergic receptor-mediated elevation of cyclic AMP in pinealocytes. These and earlier results emphasize the importance of the hydroxyl group at position 3 of the ring and at the beta-position of the side chain in catecholamine activation of the pineal alpha-adrenergic receptors, which are involved in alterations of phospholipid metabolism. 相似文献
973.
Isolation and characterization of a soybean hsp70 gene 总被引:7,自引:0,他引:7
974.
Summary Probe DNA that binds preferentially to the centromeric region of human chromosomes 8 was synthesized. Alpha satellite probe DNA molecules were selectively amplified from sorter-purified human chromosomes 8 by in vitro DNA amplification using the polymerase chain reaction (PCR). Probe labeling was performed during PCR by incorporation of biotinylated deoxyuridine. In situ hybridization of unpurified probe DNA comprised of alpha satellite monomer and higher molecular weight DNA fragments with metaphase chromosome spreads showed binding to the centromeric regions of numerous chromosomes. However, blocking with unlabeled total human alphoid DNA dramatically reduced crosshybridization to chromosomes other than 8. Under these conditions, the degenerate probe DNA allowed unambiguous visualization of domains occupied by centromeric DNA of chromosome 8 in metaphase spreads and interphase cell nuclei, thus greatly facilitating the detection of numerical chromosome aberrations in tumor cells. In situ hybridization of size-fractionated alpha satellite DNA identified the monomeric fraction as the major cause of crosshybridization. Alpha satellite dimers and higher molecular weight DNA fragments showed relatively high specificity for human chromosomes 8. 相似文献
975.
Soluble polymers of bovine Cu/Zn superoxide dismutase (EC 1.15.1.1) have been prepared using the homobifunctional cross-linking reagent, glutaraldehyde. A form of the enzyme, a tetramer. with a molecular weight of 64, 000 has been purified by gel filtration. The functional properties of the tctrarner have been investigated. Reconstitution with copper and zinc was required for full activity. After metal reconstitution, the specific activity of the tetramer was shown to be close to 90% that of the native dimerism enzyme.
The serum half-life of the tetramer in rats was found to be increased by a factor of six when compared with native superoxide dismutase. The tissue distribution of the two forms was also found to be direrent with the tetrarner accumulating predominantly in the liver. 相似文献
The serum half-life of the tetramer in rats was found to be increased by a factor of six when compared with native superoxide dismutase. The tissue distribution of the two forms was also found to be direrent with the tetrarner accumulating predominantly in the liver. 相似文献
976.
Kinetics of Ca2+-induced fusion of phosphatidylserine vesicles is studiied for lipid concentrations varying from 1 μM to 100 μM. Fusion is monitored by mixing of aqueous vesicle contents and by explicitly accounting for leakage. The analysis provides separately rates of aggregation and fusion. The rate of fusion per se decreases steeply with vesicle size. 相似文献
977.
To investigate the distribution of the tau and HMW microtubule-associated proteins (MAPS) and their relationship to microtubules in vivo, we have examined a wide variety of avian and mammalian cell types by immunofluorescence with antisera to these two proteins. Anti-HMW serum stains cytoplasmic microtubules in all mammalian cell types so far examined. However, anti-tau serum did not stain cytoplasmic microtubules in rat glial cells or in pig kidney cells. In mammalian neurons, fibroblasts and neuroblastoma cells, the staining of microtubules with both sera was similar. Anti-HMW serum did not stain primary cilia or cilia on isolated tracheal epithelial cells, whereas anti-tau serum did stain these ciliary microtubules. We believe these results indicate that some types of microtubules may be associated with only the tau or the HMW protein, whereas others may be associated with both tau and HMW protein. With respect to avian cells, anti-HMW serum did not stain microtubules in any of the three cell types examined, whereas the anti-tau serum stained them in two cell types. Furthermore, double diffusion tests indicated that anti-pig tau serum will precipitate both pig brain tau and tau protein isolated from chick brain, whereas anti-HMW serum will precipitate only pig brain and not chick brain HMW protein. We believe tau protein is antigenically similar in both avian and mammalian cells, whereas the HMW protein from these two sources is antigenically distinct. 相似文献
978.
The binding of mono-, di- and trivalent cations to negatively charged surfaces is studied within the framework of a modified
Gouy-Chapman equation. For any given combination of ions of the above valences, the existence and uniqueness of the solution
for the surface potential is shown. The treatment provides the surface potential and charge density. For a system containing
only monovalent and divalent ions, analytical solutions are given. When trivalent ions are also present, a procedure based
on numerical integration is described. The distance dependence of the electrostatic potential for planar surfaces is given.
The calculations provide the amount of cations tightly bound and the amount trapped in the double layer region. The competition
between cations for binding to surfaces is elucidated. 相似文献
979.
Andrew Magyarosy Jonathan Z. Ho Henry Rapoport Scott Dawson Joe Hancock Jay D. Keasling 《Applied microbiology》2002,68(8):4095-4101
A gram-positive Bacillus sp. that fluoresces yellow under long-wavelength UV light on several common culture media was isolated from soil samples. On the basis of carbon source utilization studies, fatty acid methyl ester analysis, and 16S ribosomal DNA analysis, this bacterium was most similar to Bacillus megaterium. Chemical extraction yielded a yellow-orange fluorescent pigment, which was characterized by X-ray crystallography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The fluorescent compound, chlorxanthomycin, is a pentacyclic, chlorinated molecule with the molecular formula C22H15O6Cl and a molecular weight of 409.7865. Chlorxanthomycin appears to be located in the cytoplasm, does not diffuse out of the cells into the culture medium, and has selective antibiotic activity. 相似文献
980.
Barry Goldfarb Glenn T. Howe Libby M. Bailey Steven H. Strauss Joe B. Zaerr 《Plant cell reports》1991,10(3):156-160
Summary The effects of high-concentration, 2-h liquid pulses of N6-benzylaminopurine (BA) and thidiazuron (TD) on adventitious bud and shoot formation were tested in cotyledons of Douglas-fir (Pseudotsuga menziesii). Seedling age proved important; on average, cotyledons from the youngest seedlings formed 10-fold more buds than cotyledons from the oldest seedlings. Optimal cytokinin concentrations for the youngest cotyledons were 400 and 800 M BA, and 100 and 200 M TD. Shoots developed best from buds induced with 300, 400, and 800 M BA. Four gelling agents were tested; BRL agarose yielded more than three times the number of buds, and Gelrite nearly twice the number of buds, as either Sigma agar or Difco Bacto-Agar. One of the best treatments (400 M BA, agarose) yielded more cotyledons with buds, and more buds per cotyledon, than when cytokinins were incorporated into the growth medium.Abbreviations BA
N6-benzylaminopurine
- TD
thidiazuron
- SH
Schenk and Hildebrandt (1972)
- NAA
1-naphthaleneacetic acid
Paper 2691 of the Forest Research Laboratory, Oregon State University, Corvallis. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the authors or Oregon State University. 相似文献