Carving The Palm: The Role of Metaphor in Mayawo Marriage Rituals

…With metaphor we experience the metamorphosis of both language and reality. Paul Ricoeur. ‘Creativity in Language’. The Philosophy of Paul Ricoeur. pp. 132–133 (1973).     

Reassessment of structural characteristics of the d(CGCG)2:actinomycin D complex from complete 1H and 31P NMR

Complexes formed between Actinomycin D (ActD) and the tetranucleotides d(AGCT)2 and d(CGCG)2 were studied in detail by one and two-dimensional 1H and 31P NMR. The 31P two dimensional chemical exchange experiment, at room temperature on saturated complexes (1:1), showed unambiguously that the asymmetrical phenoxazone ring binds to the unique GC site under the two possible orientations in the d(AGCT)2 tetranucleotide but adopts a single orientation in the d(CGCG)2 tetranucleotide. For the d(CGCG)2:Act D saturated complex, complete assignments of all protons and phosphorus signals of the two-nucleotide strands, as well as of the two cyclic pentapeptide chains has allowed us to study in details the conformational features of the complex from NOE and coupling constants analysis. The tetranucleotide remains in a right-handed duplex, but the sugar puckers are modified for residues at the intercalation site. A uniform C2' endo pucker is observed for residues on the strand facing the quinoid side of the phenoxazone ring while a C2' endo-C3-endo equilibrium about 60% of C2' endo is proposed for the two residues on the strand facing the benzenoid side of the phenoxazone ring. In contrast to previous studies on ActD-DNA interactions, we have been able to measure the 3J phosphorus-proton coupling constants at the intercalation site but also adjacent to it, showing that 31P chemical shifts are not simply related to the backbone conformation. Molecular mechanics calculations, using empirical distances deduced from NOE effects as restrained distances during minimizations, led to a model differing mainly from those previously published by orientation of the N methyl groups of both N-Methyl-Valines.     

Purification to apparent homogeneity of the somatostatin receptor of the human cell line HGT-1 of gastric origin

This communication reports the isolation and the purification of the gastric somatostatin receptor from the human cell line HGT-1. The receptor has been extracted from the cell membrane by Triton X 100, and a monoclonal antibody to this was prepared. A series of affinity chromatographies (Sepharose-antibody and Sepharose-somatostatin-14) and a final purification by steric exclusion on high performance liquid chromatography columns (HPLC) allowed us to obtain a fraction enriched 20,000 fold in 125I-Tyrll-somatostatin-14 specific binding (apparent dissociation constant: 7.6 x 10(-8) M). This fraction corresponded to a molecular mass of about 90 kDa (in presence of detergent) and to a maximal binding capacity of more than 10,000 pmol/protein. It therefore has a theoretical homogeneity close to 100%.     

A new DNA marker (D4S90) is located terminally on the short arm of chromosome 4, close to the Huntington disease gene

Genetic linkage studies have mapped Huntington's disease (HD) to the distal portion of the short arm of chromosome 4 (4p16.3), 4 cM distal to D4S10 (G8). To date, no definite flanking marker has been identified. A new DNA marker, D4S90 (D5), which maps to the distal region of 4p16.3, is described. The marker was used in a genetic linkage study in the CEPH reference families with seven other markers at 4p16. The study, together with knowledge of the physical map of the region, places D4S90 as the most distal marker, 6 cM from D4S10. A provisional linkage study with HD gave a maximum lod score of 2.14 at a θ of 0.00 and no evidence of linkage disequilibrium. As D4S90 appears to be located terminally, it should play an important role in the accurate mapping and cloning of the HD gene.     

Image analysis of rat satellite cell proliferation in vitro

Myogenic cells were isolated from adult rat skeletal muscles and cultured in vitro. Cell proliferation was analyzed between days 1 and 14. The cell cycle phases were determined by examining Feulgen-stained cultures with a cell image processor. The nuclei were automatically analyzed by calculating 18 parameters relating to the texture and densitometry of chromatin and the shape of each nucleus. Cell cycle phases were characterized (Moustafa and Brugal, 1984). The recognition methods made it possible to analyse the nuclei of the myogenic cell populations which were either involved in each phase of the mitotic cycle, or left out of the cycle after fusion into myotubes.After 3 hr of culture 10% of the cell population was involved in the cell cycle. In the presence of foetal calf serum, this percentage increased until day 3 after plating. At that time, the DNA content of 28.2% of the cell population was higher than 3C, whereas it is 2C in G1 or G0 nuclei; image analysis showed that 42% of these cells were in S or G2 phase. From day 4, the proliferation rate gradually slowed down until day 8. After day 8, when numerous myotubes differentiated, the percentage of S and G2 phase cells had diminished to between 3 and 8%. The percentage of nuclei in G0 increased when the first myotubes differentiated around day 5. Myotube nuclei were largely in G0. When horse serum was added to the culture medium on day 4 to enhance myotube differentiation, significant cell proliferation was observed before cell fusion.These methods of analysis give the first daily pattern of myogenic cell proliferation and fusion in a cell population isolated from adult muscles.     

Response of pondcypress growth rates to sewage effluent application

Cores were collected from dominant pondcypress trees growing in a swamp that had received sewage effluent for 7 yr and a nearby control swamp to determine the combined effects of changes in nutrient supply and hydrologic regime on tree growth. The cores were used to measure two indices of tree growth: basal area increment (BAI) and relative basal area increment (RBAI, which accounts for differences in growth due to the size of teh tree) between 1970–1983 while one swamp remained untreated and the other received weekly additions of sewage effluent from 1974–1981. Throughout the whole period, the mean BAI and RBAI of pond-cypress trees in the untreated swamp remained unchanged, ranging between 5.55–6.38 cm² yr^–1 and 1.09–1.27% yr^–1, respectively. In contrast, trees in the treated swamp increased their BAI approximately two-fold from 7.40 cm² yr^–1 prior to treatment to 14.83 cm² yr^–1 after the onset of treatment and maintained this rate of growth in the 2 yr period after cessation of treatment. Relative basal area increment showed a similar response, but the proportional increase due to treatment was less (1.5-fold factor) than for BAI. The response of pondcypress trees to the sewage effluent differed depending upon whether the trees were located in the deep or shallow water zones. Trees in the deep zone of the treated swamp had lower BAIs and RBAIs than those in the shallow zone during the treatment period, whereas in pre- and post-treatment periods growth indices were equal in both zones. No significant differences in growth between deep and shallow zones were observed during all three time periods in the control swamp.     

α1-Adrenergic Receptor Mediates Arachidonic Acid Release in Spinal Cord Neurons Independent of Inositol Phospholipid Turnover

The alpha 1-adrenergic receptor has been shown to mediate the release of arachidonic acid in FRTL5 thyroid cells and MDCK kidney cells. In primary cultures of spinal cord cells, norepinephrine stimulated release of arachidonic acid (from neurons only) and turnover of inositol phospholipids (from neurons and glia) via alpha 1-adrenergic receptors. These two responses were dissociated by treatment with phorbol ester and pertussis toxin, which inhibited production of inositol phosphates with no appreciable effect on release of arachidonic acid. Extracellular calcium was required for release of arachidonic acid, but not for production of inositol phosphates. The calcium channel blockers nifedipine and verapamil inhibited release of arachidonic acid only. However, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), a compound that blocks intracellular calcium release, diminished production of inositol phosphates, but had little effect on release of arachidonic acid. These results suggest that alpha 1-adrenergic receptors couple to release of arachidonic acid in primary cultures of spinal cord cells by a mechanism independent of activation of phospholipase C, possibly via the activation of phospholipase A2.     

Cytotoxic T cell responses in HLA-A2.1 transgenic mice. Recognition of HLA alloantigens and utilization of HLA-A2.1 as a restriction element

Previous studies have indicated that the frequency of murine CTL precursors (CTLp) for human class I molecules is one to two orders of magnitude lower than that for murine class I alloantigens, and that this is due to species-specific structural differences between these molecules. Transgenic mice expressing the human class I MHC Ag HLA-A2.1 were used to examine changes in the frequency of class I HLA-specific precursors after T cell differentiation in an HLA-A2.1 positive environment. The HLA-A2.1 gene product was expressed at levels comparable to those of the endogenous H-2Db molecule in thymus, bone marrow, and spleen. By limiting dilution analysis, it was observed that the frequencies of CTLp in transgenic mice responding to the human alloantigens HLA-B7 or HLA-A2.2 were comparable to or lower than those in normal C57BL/6 mice, regardless of whether the Ag was presented on human or murine cells. Thus, expression of a human class I molecule in these animals did not result in an expansion of the number of CTLp specific for other human class I Ag. In addition, the frequency of HLA-A2.1-restricted, influenza specific CTLp was substantially lower than the frequency of H-2b restricted CTLp, indicating a poor utilization of HLA-A2.1 as a restricting element. Finally, the frequencies of CTLp for HLA-A2.1 expressed on syngeneic murine tumor cells were decreased significantly. Thus, expression of HLA-A2.1 in these animals appeared to induced tolerance to this Ag. Interestingly, however, these mice were not tolerant to the HLA-A2.1 molecule expressed on human cells. This indicates that the HLA-A2.1 associated epitopes expressed on murine and human cells differ and suggests that, under these circumstances, HLA-A2.1 acts as a restricting element for human nominal Ag. These results are discussed in the context of current models of T cell repertoire development.