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21.
Anders Hay-Schmidt 《Zoomorphology》1992,112(4):189-205
Summary Planktotrophic brachiopod larvae ofGlottidia sp. have been investigated for the occurrence of glyoxylic acid induced fluorescence in catecholamines (CA), and serotonin-like (5-HT) and neuropeptide FMRFamidelike (FMRFamide) immunoreactivity (ir). The location of CA, 5-HT-ir and FMRFamide-ir cells and processes were compared with the location of neurons and nerve processes found by transmission electron microscopy. The apical ganglion contains 5-HT-ir and FMRFamideir cells and processes and CA processes. From the dorsal part of the apical ganglion extend dorsal 5-HT-ir and FMRFamide-ir processes; from the nine pairs of tentacles stage (9. pt) they project to the ventral ganglion. These dorsal lophophore processes follow themusculus lophophoralis and them. brachialis. The 5-HT-ir and some of the FMRFamide-ir processes project along the muscles to the tentacles. From the ventral part of the apical ganglion extend CA, 5-HT-ir and FMRFamide-ir processes which follow the ciliary band of the lophophore and project to the tentacles. An intense band of CA processes was also observed in the lophophore, but the dorsal/ventral location could not be ascertained. The ventral ganglion contains 5-HT-ir and FMRFamide-ir cells which project either caudally on the metasome or rostrally as part of the dorsal lophophore processes. The neuropil of the ventral ganglion contains CA, 5-HT-ir and FMRFamide-ir processes. The nervous system of the planktotrophic brachiopod larvae seems to consist of a ventral lophophore system innervating the ciliary bands and a dorsal lophophore system including the ventral ganglion innervating the body musculature. The latter system develops later in ontogeny and is regarded as a specialization due to the presence of shells and associated musculature. The former system is regarded as homologous with the nervous system of actinotroch larvae (Phoronida) and planktotrophic larvae of the echinoderms. 相似文献
22.
Effect of pyridoxine on tumor necrosis factor activitiesin vitro 总被引:1,自引:0,他引:1
Clinical trials with tumor necrosis factor (TNF) as an antitumor agent have so far given rather disappointing results. In this study we show that the naturally occuring vitamin B6 compound, pyridoxine, enhances TNF-induced cytolysis of three subclones of a mouse fibrosarcoma cell line (WEHI 164). The degree of pyridoxine-induced enhancement of TNF cytotoxicity seems to be dependent on the cells sensitivity to TNF, as the enhancement was much more pronounced in the relatively TNF resistant subclone act-R(cl.12)-WEHI 164, than in the very TNF sensitive subclone WEHI 164 clone 13. Furthermore, our study shows that pyridoxine, in contrast to its enhancing effect on TNF-induced cytotoxicity, rather inhibits TNF-induced growth of human FS-4 fibroblasts. Pyridoxine also enhances lymphotoxin (LT)-induced tumor cell killing and inhibits LT-induced fibroblast growth. Pyridoxine is a relatively non-toxic agentin vivo. Our results suggest that a combination of TNF and pyridoxine may be more efficient than TNF alone, in the treatment of cancer patients. 相似文献
23.
24.
In the past year, additional experimental data have expanded our understanding of the molecular mechanisms that underlie nuclear receptor control of regulatory programs. It is increasingly clear -that steroid members (e.g. glucocorticoid and estrogen) and non-steroid members (e.g. retinoic acid, thyroid hormone, and vitamin D) of the nuclear receptor superfamily may utilize distinct strategies in achieving their complex control of gene regulation. 相似文献
25.
The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms 下载免费PDF全文
John B. Graham Dennis B. Lubahn Susan T. Lord Julie Kirshtein Inga Marie Nilsson Anders Wallmark Rolf Ljung L. D. Frazier Jerry L. Ware Shu Wah Lin Darrell W. Stafford John Bosco 《American journal of human genetics》1988,42(4):573-580
A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148thr) are designated Malmö A, and negative reactors (148ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ~50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men. 相似文献
26.
Identification and characterization of a major early cytomegalovirus DNA-binding protein 总被引:9,自引:8,他引:1 下载免费PDF全文
We characterized a DNA-binding protein with an approximate molecular weight of 129,000 (DB129) which is present in the nuclei of cytomegalovirus- (strain Colburn) infected cells, but not in virus particles. Results of two types of experiments demonstrated that DB129 is a member of the early class of herpesviral proteins. First, time course pulse-labeling experiments showed that its synthesis begins after that of the immediate-early protein IE94, but prior to the appearance of late viral proteins, and was reduced at late times. Second, in the presence of inhibitors of viral DNA replication, DB129 continued to be made and accumulated to elevated levels. A second set of experiments showed that DB129 bound to single-stranded DNA in vitro and was eluted by a NaCl gradient in two peaks, one at about 0.2 M and the second at about 0.6 M. A similar pattern of release was observed when infected-cell nuclei were serially extracted with increasing NaCl concentrations. In addition, treatment of nuclei with DNase I selectively released DB129, along with a small but significant fraction of another DNA-binding protein, DB51. These results suggest that DB129 is associated with DNA in vivo and that it interacts directly with single-stranded DNA. It was also shown that cells infected with human cytomegalovirus (strain Towne) contain a slightly larger counterpart to DB129, which was designated DB140. Similarities between these proteins and the major DNA-binding protein of herpes simplex virus are discussed. 相似文献
27.
Relationship between mitogenic activity of influenza viruses and the receptor-binding specificity of their hemagglutinin molecules 总被引:4,自引:0,他引:4 下载免费PDF全文
The relationship between the mitogenic activity of influenza type A viruses for murine B lymphocytes and the receptor-binding specificity of their hemagglutinin was examined. Receptor-binding specificity was determined by the ability of the virus to agglutinate erythrocytes that had been sialidase treated and then enzymatically resialylated to contain sialyloligosaccharides with defined sequences. Distinct differences in receptor-binding specificity were observed between strongly and weakly mitogenic viruses of the H3 subtype, with strong mitogenic activity correlating with the ability of the virus to recognize the sequence N-glycolylneuraminic acid alpha 2,6 galactose (NeuGc alpha 2,6Gal). Viruses isolated early in the evolution of the H3 subtype (from 1968 to 1971) are relatively weak mitogens and recognize the sequence N-acetylneuraminic acid alpha 2,6 galactose (NeuAc alpha 2,6Gal) but not NeuGc alpha 2,6Gal. H3 viruses isolated since 1972 are strongly mitogenic, and these viruses recognize both NeuGc alpha 2,6Gal and NeuAc alpha 2,6Gal. The amino acid substitution of Tyr for Thr at residue 155 of HA1 may be critical to this change in receptor-binding specificity and mitogenic activity of the later H3 viruses. Horse serum-resistant variants of H3 viruses, which bind preferentially to the sequence NeuAc alpha 2,3Gal, are poorly mitogenic. Differences were also observed between the receptor-binding specificity of the strongly mitogenic H3 viruses and viruses of the H2 and H6 subtypes, the mitogenic activity of which is limited to strains of mice that express the class II major histocompatibility complex glycoprotein I-E. The results indicate that the receptor-binding specificity of the hemagglutinin plays a critical role in determining the mitogenic activity of influenza viruses. 相似文献
28.
Nitropyrenes are mutagenic to E. coli strains that have increased permeabilities to large molecules and carry plasmid pKM101. 相似文献
29.
Anders Stigebrandt 《Palaeogeography, Palaeoclimatology, Palaeoecology》1985,50(1):303-321
A theoretical investigation of the hydrographic conditions in the northern North Atlantic (N of the Greenland—Scotland Ridge) for different forcing conditions is undertaken. First a simple dynamical model for the “mediterranean” circulation in the Greenland and Norwegian seas (the Subpolar Sea) is developed. The calculated contemporary rate of deepwater formation (about 2.5 × 106 m3/s) seems to be quite realistic. It is concluded that the mediterranean circulation is possible as long as the cyclonal atmospheric circulation in the Subpolar Sea is strong enough to prevent the fresher water in the coastal currents along the eastern and western boundaries from spreading over the interior.Utilizing the Arctic Ocean model in Stigebrandt (1981) the hydrographic and ice conditions in the Subpolar Sea and the Arctic Ocean during different phases of a glaciation are, finally, investigated. As so many parameters are involved the derivations are, by necessity, rather uncertain. However, it seems possible that the hydrographic state in the Subpolar Sea changes between mediterranean and estuarine circulation several times during a glacial cycle. 相似文献
30.
N-Methylaspartate-Evoked Liberation of Taurine and Phosphoethanolamine In Vivo: Site of Release 总被引:2,自引:1,他引:1
The effect of N-methyl-D,L-aspartic acid (NMA) on extracellular amino acids was studied in the rabbit hippocampus with the brain dialysis technique. Administration of 0.5 or 5 mM NMA caused a concentration-dependent liberation of taurine and phosphoethanolamine (PEA). Taurine increased by 1,200% and PEA by 2,400% during perfusion with 5 mM NMA whereas most other amino acids rose by 20-100%. The effect of NMA appeared to be receptor-mediated, as coperfusion with D-2-amino-5-phosphonovaleric acid curtailed the NMA response by some 90%. The NMA-stimulated release of taurine and PEA was suppressed when Ca2+ was omitted and further inhibited when Co2+ was included in the perfusion medium. The effect of NMA was mimicked by the endogenous NMA agonist quinolinic acid and the partial NMA agonist D,L-cis-2,3-piperidine dicarboxylic acid. Although the NMA-evoked release of taurine and PEA was Ca2+-dependent in vivo, NMA had no effect on Ca2+ accumulation in hippocampal synaptosomes. The previously reported NMA-induced activation of dendritic Ca2+ spikes and the lack of effect on synaptosomal Ca2+ uptake suggest that taurine and PEA are released from sites other than nerve terminals, possibly from dendrosomatic sites. This notion was strengthened by the absence of an effect of NMA on the efflux of radiolabelled taurine from hippocampal synaptosomes. In contrast, high K+ stimulated synaptosomal uptake of Ca2+ and release of taurine. 相似文献