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1.
S. Goldenberg J.M. Salles V.T. Contreras M.P.Lima Franco A.M. Katzin W. Colli C.M. Morel 《FEBS letters》1985,180(2):265-270
The cell-free translation products of polyribosomal and post-polyribosomal mRNAs from the non-infective epimastigotes and the infective metacyclic trypomastigotes of the parasitic protozoan Trypanosoma cruzi were compared by two-dimensional polyacrylamide gel electrophoresis. The result show that although many polypeptides are conserved, quantitative and qualitative differences are observed between both differentiation stages. The results also indicate the existence of post-polyribosomal mRNAs in equilibrium with polyribosomal counterparts. The immunoprecipitation of the in vitro synthesized polypeptides with chagasic human serum and the serum raised against an 85-kDa glycoprotein (P2-WGA), potentially involved in the process of T. cruzi penetration into mammalian cells, shows that while the chagasic serum recognizes the same 72-kDa, 68-kDa and 46-kDa polypeptides in both differentiation stages, the anti-P2-WGA serum immunoprecipitates a single 48-kDa polypeptide from in vitro translation products of metacyclic trypomastigotes. 相似文献
2.
The nucleoside triphosphate (NTP) pool during the early development of sea-urchin, Paracentrotus lividus, was measured using high-performance liquid chromatography (HPLC). Each NTP pool was measured at four stages between the eight-blastomere stage and the early blastula stage, as was the specific activity of each NTP following an initial administration of 8-3H-guanosine. Unexpectedly high UTP (uridine-5'-triphosphate) concentrations and radioactivity levels in UTP were observed. Studies of the sea-urchin, Strongilocentrotus purpuratus, also revealed elevated levels of 8-3H-guanosine incorporation into UTP. The present procedure was found to be suitable for the unequivocal identification of UTP. 相似文献
3.
4.
Growth hormone-releasing factor (GRF) is a hypothalamic peptide named for its ability to induce release of growth hormone from the anterior pituitary. GRF also acts as a neurotransmitter in the suprachiasmatic nucleus/medial preoptic area (SCN/MPOA) to stimulate food intake. The purpose of this series of experiments was to explore the nature of GRF-induced feeding, with a particular emphasis on macronutrient selectivity, and to examine the role of opiate activity in the paraventricular nucleus of the hypothalamus (PVN). Chow intake stimulated by GRF microinjection (1 pmol/0.5 μl) into the SCN/MPOA was blocked by injection of methyl-naltrexone (3 μg/0.5 μl) into the PVN. In animals habituated to macronutrient diets (Teklad, WI), GRF preferentially stimulated intake of protein at 2 and 4 h postinjection, whereas it had no effect on carbohydrate intake. Further, this effect was blocked by injection of naloxone (40 nmol/0.5 μl) into the PVN. Microinjection of morphine (0, 1, 10, and 17 μg/0.5 μl) into the PVN also specifically stimulated protein intake at 2 and 4 h postinjection. These results suggest that feeding derived from GRF actions in the SCN/MPOA is macronutrient selective, and is dependent on PVN opiate activity for expression. 相似文献
5.
C. F. C. Klütsch B. Misof W.-R. Grosse R. F. A. Moritz 《Journal of Biogeography》2007,34(7):1124-1135
Aim Anole lizards (Reptilia: Sauria: Polychrotidae) display remarkable morphological and genetic differentiation between island populations. Morphological differences between islands are probably due to both adaptive (e.g. differential resource exploitation and intra‐ or interspecific competition) and non‐adaptive differentiation in allopatry. Anoles are well known for their extreme diversity and rapid adaptive speciation on islands. The main aim of this study was to use tests of morphological and genetic differentiation to investigate the population structure and colonization history of islands of the Islas de Bahia, off the coast of Honduras. Location Five populations of Norops bicaorum and Norops lemurinus were sampled, four from islands of the Islas de Bahia and one from the mainland of Honduras. Methods Body size and weight differentiation were measured in order to test for significant differences between sexes and populations. In addition, individuals were genotyped using the amplified fragment length polymorphism technique. Bayesian model‐based and assignment/exclusion methods were used to study genetic differentiation between island and mainland populations and to test colonization hypotheses. Results Assignment tests suggested migration from the mainland to the Cayos Cochinos, and from there independently to both Utila and Roatán, whereas migration between Utila and Roatán was lacking. Migration from the mainland to Utila was inferred, but was much less frequent. Morphologically, individuals from Utila appeared to be significantly different in comparison with all other localities. Significant differentiation between males of Roatán and the mainland was found in body size, whereas no significant difference was detected between the mainland and the Cayos Cochinos. Main conclusions Significant genetic and morphological differentiation was found among populations. A stepping‐stone model for colonization, in combination with an independent migration to Utila and Roatán, was suggested by assignment tests and was compatible with the observed morphological differentiation. 相似文献
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7.
A note on the hatching and viability ofCeriodaphnia ephippia collected from lake sediment 总被引:3,自引:3,他引:0
Christian Moritz 《Hydrobiologia》1987,145(1):309-314
Ephippia ofCeriodaphnia pulchella Sars were collected at 2 sites from successive sediment layers.
Hatching observed in the laboratory gave information about the duration of their viability. Conclusions about the hatching
situation in the lake were drawn from the ratio of intact to total ephippia at various lake depths. The results are discussed. 相似文献
8.
Marina Ripamonti Silvana Canevari Sylvie Ménard Delia Mezzanzanica Silvia Miotti Rosaria Orlandi Franco Rilke Elda Tagliabue Maria Ines Colnaghi 《Cancer immunology, immunotherapy : CII》1987,24(1):13-18
Summary In order to investigate in vivo clinical applications of murine monoclonal antibodies directed against human ovarian carcinoma a preclinical in vivo model was developed using BALB/c athymic mice. Three human carcinoma cell lines (MCF7, HT29, and SW626) were injected into the peritoneal cavity of pristane-primed animals and the biological and antigenic characteristics of the i.p. grown tumors were studied. The animals were killed when moribund or 6–8 weeks after tumor injection. At autopsy tumor take was observed in 85% of the injected animals, whereas palpable nodules were evident in only 83%. Examination of the peritoneal cavity revealed intraabdominal carcinomatosis with tumor masses varying in size between 0.2 and 0.5 cm in diameter and tumor sheets. The most frequently affected organs were the diaphragm, the liver, and the reproductive system. Ascitic fluid formation was rare and no animal developed tumors outside the peritoneal cavity. To determine whether the in vivo tumors retained the same antigenic characteristics as the in vitro cell lines, four monoclonal antibodies (MBrl, MOv2, MOv8, and MOv15) directed against ovarian carcinoma-associated antigens and two different experimental approaches (immunofluorescence and immunoblotting) were used. Variations at either a quantitative or a qualitative level were observed for some antigens, whereas no evident changes were apparent for others. In particular, the antigens detected by MBr1 and MOv15 on the MCF7 line both maintained high levels of expression and immunoblotting staining pattern, whereas the antigens detected by MOv2 on the HT29 and SW626 lines, although present at a high level, clearly changed their staining pattern. As regards the antigens recognized by MOv8 and MOv15 on the HT29 and SW626 lines, we observed a drastic decrease in the level of their expression and in many cases a drop below the threshold of detectability of the test. The intraabdominal carcinomatosis described partially mimics the growth characteristics of human ovarian cancer and maintains the expression of some antigenic markers associated with epithelial tumors of the ovary and may therefore be useful in devising immunodiagnostic and/or immunotherapeutic strategies for ovarian carcinoma. 相似文献
9.
Gianfranco Canti Laura Ricci Ornella Marelli Paola Franco Angelo Nicolin 《Cancer immunology, immunotherapy : CII》1987,24(1):64-67
Summary New antigenic specificities, not detectable on parental cells, have been induced by many investigators in mouse lymphomas by treatment with the antitumor agent 5(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC). The antigens are transmissible, after withdrawal of the drug treatment, as an inheritable character. The mechanism of induction, the molecular nature, and the number of the new antigenic specificities have not been completely elucidated. Four clones from murine leukemia L1210 isolated and expanded in vitro were treated in vivo with DTIC and the new sublines were studied in detail. The four drug-treated sublines studied exhibited strong immunogenicity since they were rejected by syngeneic animals. Immunosuppressed animals challenged with 107 A/DTIC or P/DTIC cells were reciprocally protected by the adoptive transfer of spleen cells from donors that had rejected a lethal challenge of A/DTIC or P/DTIC clones. In a similar fashion, the adoptive transfer of spleen cells obtained from animals that had rejected the Q/DTIC or the R/DTIC clones protected immunosuppressed mice challenged with Q/DTIC or R/DTIC cells. No antitumor activity was observed in cross-protective schedules other than those indicated. It was been concluded that (a) the L1210 leukemia line does not have antigenic cells, (b) four DTIC-treated clone sublines were rejected by compatible hosts, and (c) two mutually exclusive sets of antigens were expressed in four antigenic clone sublines.Research supported in part by P.F.O. Contract Grant from C. N. R., Rome, Italy 相似文献
10.
Neutral gene flow in an island model in the presence of a gene subject to selection has been analysed. The selection regime on the gene is such that the maintenance of a stable interpopulation differentiation at this locus is allowed for very low values of the migration rate. Mating at this locus may be random or assortative. Many models of zygotic or prezygotic isolating mechanisms with unifactorial inheritance are represented by this genetic model. Two general solutions for migration rates tending toward zero have been obtained for the case of migration preceding selection and vice versa. It is found that the zygotic isolating mechanisms and one type of prezygotic isolating mechanisms have the same qualitative and quantitative effects for the same values of selection coefficients and of recombination frequencies between the selected gene and the neutral gene. A second type of prezygotic mechanism behaves in a different way: the reduction of gene flow caused by such mechanisms is also a function of the “mating coefficients” of the various genotypes. 相似文献