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11.
Astroglial-like cells from the glycogen body and astroglia from the cerebral hemispheres of chick embryos cultured 6 days in vitro exhibit comparable values of L-glutamate and L-aspartate uptake. The uptake is significantly reduced by inhibitors of gamma-glutamyl transpeptidase. 相似文献
12.
Martin Cambray-Deakin Brian Pearce Christine Morrow Sean Murphy 《Journal of neurochemistry》1988,51(6):1846-1851
Astrocyte-enriched and meningeal cell cultures of the rat cerebral cortex were prepared, and their glycogen content was measured after 10-90 min under control (2.5 mM) concentrations of potassium after prefeeding with 20 mM glucose. No net change in glycogen level was noted in either culture over this period. Cell cultures were then exposed to increased concentrations of potassium (5, 10, and 15 mM), and their glycogen content was measured after 10-90 min. Both types of cell culture showed complex and variable changes in glycogen content. In general, increased potassium concentrations caused astrocyte glycogen stores to be reduced at physiological increases of potassium levels (from 2.5 to 5 mM and above), although a period of resynthesis was evident at all potassium concentrations. Meningeal cell glycogen levels were highly variable and only affected by high (10 and 15 mM) levels of potassium. These results are discussed with respect to the theory that changes in the external potassium concentration caused by neuronal activity might act as a signal controlling astrocyte glycogen stores. 相似文献
13.
The juice of unripe fruit from a wild species of tomato, Lycopersicon peruvianum (L.) Mill., LA 107, contains over 50% of its soluble proteins as the sum of two proteinase inhibitors. These are the highest levels of proteinase inhibitors and highest percentage of soluble proteins as proteinase inhibitors of any plant or animal tissue found to date. Fruit of the modern tomato, L. esculentum Mill., contains only negligible quantities of the two inhibitors. The two proteinase inhibitors in the fruit of L. peruvianum are members of the Inhibitor I and II families previously found in potato tubers and in leaves of wounded potato and tomato plants. The levels of the two inhibitors in the unripe fruit decrease significantly during ripening. Unripe fruit from other wild Lycopersicon species such as L. parviflorum Rick, Kesicki, Fobes et Holle, L. hirsutum Humb. et Bonpe., L. pimpinellifolium Mill., and other lines of L. peruvianum contain moderate levels of the inhibitors that also decrease during ripening. Another wild tomato species, L. pennellii Corr., is similar to L. esculentum in not containing the two proteinase inhibitors in either unripe or ripe fruit. The transient levels of the inhibitors in fruit of wild species indicate that they are present in unripe fruit as defensive chemicals against insects, birds or small mammals and their disappearance during ripening may render them edible to facilitate seed dispersal. High levels of mRNAs coding for Inhibitors I and II in unripe fruit of L. peruvianum, LA 107, indicate that strong promoters may regulate the developmentally expressed proteinase-inhibitor genes in tomato fruit that may have a substantial potential for use in genetic-engineering experiments to enhance the production of large quantities of proteinase inhibitors or other proteins in field tomatoes.Abbreviations poly(A)+ mRNA
polyadenylated mRNA
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide electrophoresis
Project 1791, College of Agriculture and Home Economics Research Center, Washington, State University 相似文献
14.
Development of rat anti-mouse interleukin 3 monoclonal antibodies which neutralize bioactivity in vitro 总被引:10,自引:0,他引:10
Several rat anti-mouse interleukin 3 (IL-3) monoclonal antibodies have been developed which inhibit the biologic activity of mouse IL-3. These antibodies were produced in rats immunized with preparations of purified, recombinant mouse IL-3, obtained from transiently transfected COS7 cell supernatant. Hybridomas secreting anti-IL-3 were selected initially either on the basis of their giving a positive signal in an indirect enzyme-linked immunosorbent assay, or for their ability to inhibit the proliferation of the IL-3-dependent mouse mast cell line, MC/9. Neutralizing rat monoclonal IgG1, IgG2a, and IgG2b antibodies have been identified; these also block IL-3-induced proliferation of the NFS-60 and IC2 cell lines. These antibodies also blocked the IL-3-induced proliferation of mouse bone marrow-derived colony-forming units-culture suggesting that the same epitopes on IL-3 influence receptor recognition for both the proliferation of factor-dependent cell lines as well as normal bone marrow cells. Fab fragments produced from certain of the IgG2a-neutralizing antibodies blocked as well as the parent IgG. Antibody cross-blocking studies identified one neutralizing antibody apparently recognizing an epitope that was spatially distinct from those recognized by the other blocking antibodies tested. The development of these neutralizing rat monoclonal antibodies to mouse IL-3 should facilitate further investigation on the role of this factor in hemopoietic regulation. 相似文献
15.
Mapping of locus for X-linked congenital stationary night blindness (CSNB1) proximal to DXS7. 总被引:4,自引:0,他引:4
A recombinant chromosome in a male affected with X-linked congenital stationary night blindness (CSNB1) provides new information on the location of the CSNB1 locus. A four-generation family with five males affected with X-linked CSNB was analyzed with five polymorphic markers for four X-chromosome loci spanning the region OTC (Xp21.1) to DXS255 (Xp11.22). Four of the males inherited the same X chromosome; one male inherited a chromosome that from OTC to DXS7, inclusive, was derived from the normal X chromosome of his unaffected grandfather and that from a location between DXS7 and DXS426 proximally was derived from the chromosome carrying the CSNB1 locus. This recombinant maps the CSNB1 locus in this family to a region on the short arm of the X chromosome proximal to the DXS7 locus. 相似文献
16.
Summary The sequence and genetic organization was determined of the 2508 by lactococcal portion of pFX2, which was derived from a
crypticLactococcus lactis subsp.lactis plasmid and used as the basis for construction of a series of lactococcal vectors. A lactococcal plasmid plus origin and
two replication protein-coding regions (repA andrepB) were located. RepA has a helix-turn-helix motif, a geometry typical of DNA-binding proteins. RepB shows a high degree of
homology to the plasmid replication initiation proteins from other gram-positive bacteria andMycoplasma. The transcribed inverted repeat sequence betweenrepA andrepB could form an attenuator to regulate pFX2 replication. Upstream of theori site, and in a region which was non-essential for replication, a 215 by sequence identical to the staphylococcal plasmid
pE194 and carrying the RSA site was identified. The genetic organization of this lactococcal plasmid replicon shares significant similarity with pE194
group plasmids. 相似文献
17.
Elongation of hypocotyls of sunflower can be promoted by gibberellins (GAs) and inhibited by ethylene. The role of these hormones in regulating elongation was investigated by measuring changes in both endogenous GAs and in the metabolism of exogenous [3H]- and [2H2]GA20 in the hypocotyis of sunflower (Helianthus annuus L. cv Delgren 131) seedlings exposed to ethylene. The major biologically active GAs identified by gas chromatography-mass spectrometry were GA1, GA19, GA20, and GA44. In hypocotyls of seedlings exposed to ethylene, the concentration of GA1, known to be directly active in regulating shoot elongation in a number of species, was reduced. Ethylene treatment reduced the metabolism of [3H]GA20 and less [2H2]GA1 was found in the hypocotyls of those seedlings exposed to the higher ethylene concentrations. However, it is not known if the effect of ethylene on GA20 metabolism was direct or indirect. In seedlings treated with exogenous GA1 or GA3, the hypocotyls elongated faster than those of controls, but the GA treatment only partially overcame the inhibitory effect of ethylene on elongation. We conclude that GA content is a factor which may limit elongation in hypocotyls of sunflower, and that while exposure to ethylene results in reduced concentration of GA1 this is not sufficient per se to account for the inhibition of elongation caused by ethylene. 相似文献
18.
A sequence motif found in a Drosophila heterochromatin protein is conserved in animals and plants. 总被引:22,自引:3,他引:19
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P B Singh J R Miller J Pearce R Kothary R D Burton R Paro T C James S J Gaunt 《Nucleic acids research》1991,19(4):789-794
Modifiers of position-effect-variegation in Drosophila encode proteins that are thought to modify chromatin, rendering it heritably changed in its expressibility. In an attempt to identify similar modifier genes in other species we have utilized a known sequence homology, termed chromo box, between a suppressor of position-effect-variegation, Heterochromatin protein 1 (HP1), and a repressor of homeotic genes, Polycomb (Pc). A PCR generated probe encompassing the HP1 chromo box was used to clone full-length murine cDNAs that contain conserved chromo box motifs. Sequence comparisons, in situ hybridization experiments, and RNA Northern blot analysis suggest that the murine and human sequences presented in this report are homologues of the Drosophila HP1 gene. Chromo box sequences can also be detected in other animal species, and in plants, predicting a strongly conserved structural role for the peptide encoded by this sequence. We propose that epigenetic (yet heritable) changes in gene expressibility, characteristic of chromosomal imprinting phenomena, can largely be explained by the action of such modifier genes. The evolutionary conservation of the chromo box motif now enables the isolation and study of putative modifier genes in those animal and plant species where chromosomal imprinting has been described. 相似文献
19.
20.
In a series of experiments spermatozoa were inseminated blindly into the vagina of ewes and then recovered at varying times after insemination. Most of the spermatozoa inseminated were lost by drainage through the vulva. The rate of loss was not affected by the motility of spermatozoa or oestrous state of the ewe. Initially after insemination the loss was not rapid with 82% of the insemination 18% of spermatozoa remained and by 12 h 10% remained. Spermatozoa were removed from the vagina during withdrawal of the penis after intromission and the extent of this loss varied between rams and with the volume of semen already in the vagina. Up to half the inseminate was lost in this way when there was 0.5 ml of semen in the vagina but only 11% was lost when the volume of inseminate was 0.1 ml. The unavoidable loss of spermatozoa may influence the quantity available for fertilizing ova. 相似文献