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931.
León LG Machín RP Rodríguez CM Ravelo JL Martín VS Padrón JM 《Bioorganic & medicinal chemistry letters》2008,18(19):5171-5173
A set of gamma-lactones alpha,beta-fused and beta,gamma-fused to carbocycles have been synthesized and evaluated for their in vitro antiproliferative activities using the human cancer cell lines SW1573 (lung), T-47D (breast) and WiDr (colon). The compounds are obtained by intramolecular ring closing metathesis of the corresponding dienes. Active compounds exhibited GI(50) values in the range 8-18 microM. A structure-activity relationship is also discussed. 相似文献
932.
Partial purification and characterization of a non-specific acid phosphatase in leaves and root nodules of Phaseolus vulgaris. 总被引:1,自引:0,他引:1
Noel A Tejera García Marleni Olivera Carmen Iribarne Carmen Lluch 《Plant Physiology and Biochemistry》2004,42(7-8):585-591
Acid phosphatase (ACP) activity in common bean grown with or without 1.5 mM of phosphate has been examined. Leaves and root nodules responded to the absence of an exogenous phosphate source with an increase in ACP activity. Increases in enzyme activity were not associated with the synthesis of new isoforms of the enzyme. We partially purified and characterized the ACPs, which consisted of three proteins, one of leaf and two of nodule. Proteins of leaf migrated at 72 and 51 kDa in SDS-PAGE, whereas that of nodule migrated at 72, 49, 41 and 34 kDa. Enzymes of both organs had a pH optimum of 5.6, and were relatively heat stable. The enzymes exhibit a broad substrate selectivity, with maximal activity obtained with alpha-naphthyl-phosphate, ribulose 1,5-bisphosphate and p-nitrophenyl-phosphate (p-NPP). Potent inhibition by Zn2+, Hg2+, Cu2+, Pb2+, Al3+ and (MoO4)2- was observed. 相似文献
933.
Marc Claret Helena Corominola Ignasi Canals Beln Nadal Alain Chavanieu Bruno Pfeiffer Pierre Renard Carmen Gorostiaga Philippe Delagrange Grard Grassy Ramon Gomis 《Obesity (Silver Spring, Md.)》2004,12(10):1596-1603
Objective: To investigate the effect of S 23521, a new glucagon‐like peptide‐1‐(7‐36) amide analogue, on food intake and body weight gain in obese rats, as well as on gene expression of several proteins involved in energy homeostasis. Research Methods and Procedures: Lean and diet‐induced obese rats were treated with either S 23521 or vehicle. S 23521 was given either intraperitoneally (10 or 100 μg/kg) or subcutaneously (100 μg/kg) for 14 and 20 days, respectively. Because the low‐dose treatment did not affect food intake and body weight, the subcutaneous treatment at high dose was selected to test the effect on selected end‐points. Results: Treated obese rats significantly decreased their cumulative energy intake in relation to vehicle‐treated counterparts (3401 ± 65 vs. 3898 ± 72 kcal/kg per 20 days; p < 0.05). Moreover, their body weight gain was reduced by 110%, adiposity was reduced by 20%, and plasma triglyceride levels were reduced by 38%. The treatment also improved glucose tolerance and insulin sensitivity of obese rats. Regarding gene expression, no changes in uncoupling protein‐1, uncoupling protein‐3, leptin, resistin, and peroxisome proliferator‐activated receptor (PPAR)‐γ were observed. Discussion: S 23521 is an effective glucagon‐like peptide‐1‐(7‐36) amide analogue, which induced a decrease in energy intake, body weight, and adiposity in a rat model of diet‐induced obesity. In addition, the treatment also improved glucose tolerance and insulin sensitivity of obese rats. These results strongly support S 23521 as a putative molecule for the treatment of obesity. 相似文献
934.
Caroline Davis Robert D. Levitan Pierandrea Muglia Carmen Bewell James L. Kennedy 《Obesity (Silver Spring, Md.)》2004,12(6):929-935
Objective: To demonstrate that human overeating is not just a passive response to salient environmental triggers and powerful physiological drives; it is also about making choices. The ventromedial prefrontal cortex has been strongly implicated in the neural circuitry necessary for making advantageous decisions when various options for action are available. Decision‐making deficits have been found in patients with ventromedial prefrontal cortex lesions and in those with substance dependence—impairments that reflect an inability to advantageously assess future consequences. That is, they choose immediate rewards in the face of future long‐term negative consequences. Research Methods and Procedures: We extended this research to the study of overeating and overweight, testing a regression model that predicted that poor decision making (as assessed by a validated computerized gambling task) and a tendency to overeat under stress would correlate with higher BMI in a group of healthy adult women (N = 41) representing a broad range of body weights. Results: We found statistically significant main effects for both independent variables in the predicted direction (p < 0.05; R2 = 0.35). Indeed, the decision‐making impairments across the 100 trials of the computer task were greater in those with high BMI than in previous studies with drug addicts. Discussion: Findings suggested that cortical and subcortical processes, which regulate one's ability to inhibit short‐term rewards when the long‐term consequences are deleterious, may also influence eating behaviors in a culture dominated by so many, and such varied, sources of palatable and calorically dense sources of energy. 相似文献
935.
Tuya Fernando Boyra Arturo Sanchez-Jerez Pablo Barbera Carmen Haroun Ricardo 《Hydrobiologia》2004,519(1-3):211-214
We sampled 36 coastal rocky reefs throughout the overall Canarian Archipelago and consider (1) the daily macroalgal consumption of the long-spined sea urchin Diadema antillarum and (2) the daily net production of macroalgae along temperate rocky-substrates, to provide evidence that Diadema antillarum plays an important role in the structure of the shallow benthic environment of the eastern Atlantic. D. antillarum was found to be the main key-herbivore species, as it controls by its own the algal assemblages, with negligible contribution of other grazing species. 相似文献
936.
Hernando A. del Portillo Michael Lanzer Sergio Rodriguez-Malaga Fidel Zavala Carmen Fernandez-Becerra 《International journal for parasitology》2004,34(13-14):1547
It is generally accepted that Plasmodium vivax, the most widely distributed human malaria, does not cytoadhere in the deep capillaries of inner organs and thus this malaria parasite must have evolved splenic evasion mechanism in addition to sequestration. The spleen is a uniquely adapted lymphoid organ whose central function is the selective clearance of cell and other particles from the blood, and microbes including malaria. Splenomegaly is a hallmark of malaria and no other disease seems to exacerbate this organ as this disease does. Besides this major selective clearance function however, the spleen is also an erythropoietic organ which, under stress conditions, can be responsible for close to 40% of the RBC populations. Data obtained in experimental infections of human patients with P. vivax showed that anaemia is associated with acute and chronic infections and it has been postulated that the continued parasitemia might have been sufficient to infect and destroy most circulating reticulocytes. We review here the basis of our current knowledge of variant genes in P. vivax and the structure and function of the spleen during malaria. Based on this data, we propose that P. vivax specifically adhere to barrier cells in the human spleen allowing the parasite to escape spleen-clearance while favouring the release of merozoites in an environment where reticulocytes, the predominant, if not exclusive, host cell of P. vivax, are stored before their release into circulation to compensate for the anaemia associated with vivax malaria. 相似文献
937.
938.
Responses of massive and branching coral species to the combined effects of water temperature and nitrate enrichment 总被引:1,自引:0,他引:1
The branching coral species Pocillopora damicornis (Linnaeus) and the massive coral species Porites lobata Dana were exposed for 30 days to different temperatures and nitrate concentrations to study the response of the coral-zooxanthella symbiosis. Results suggest that the effect of nitrate enrichment on the polyp-zooxanthella symbiosis varies according to the coral morphology. After the experimental period only 30% of P. damicornis colonies remained healthy, in contrast to 90% of P. lobata. The branching P. damicornis was significantly affected by the addition of nitrate, whereas P. lobata was significantly influenced by water temperature. The two species showed enhanced zooxanthella volume, and chlorophyll contents per cell under high nitrate concentrations. The reduced zooxanthellae density in both species indicated a detrimental influence of the interaction of high nitrate and high temperature. Tissue soluble proteins in P. lobata were significantly reduced by elevated temperature. Results showed that tissue soluble proteins and chlorophylls in P. lobata were from two- to three-fold higher than in P. damicornis. The number of zooxanthellae in P. lobata was double that of P. damicornis. Therefore, we suggest that the slow-growing species P. lobata is better able to cope with changing environmental conditions than the fast-growing coral P. damicornis. 相似文献
939.
OBJECTIVE: To compare the diagnostic value of cytology and immunohistochemistry staining (IHS) of urine samples for polyomavirus reactivation diagnosis. STUDY DESIGN: Sixty-eight urine samples collected from 18 immunosuppressed patients were analyzed by Papanicolaou and IHS with a JC/BK virus-specific monoclonal antibody. RESULTS: Overall, polyomavirus BK (BKV) was positive in 11 of 18 patients (61.1%) (3 of whom developed hemorrhagic cystitis) and in 23 of 68 urine samples (28%). Of 23 samples, 4 (17%) were positive by 1 of the 2 techniques, only. Of 23 samples, 19 (83%) were positive by both methods. In matching urine samples from the same patient, the number of BKV-infected positive cells detected by IHS in urine slides was higher than those detected by Papanicolaou staining (71.3%). CONCLUSION: The main advantage of LHS is that it allowed confirmation of BKV infection diagnosis in urine samples. IHS detected more BKV-infected cells in samples with few positive urothelial cells, which would have gone undetected if only Papanicolaou staining had been used as the BKV screening method. Urine samples testing for BKV by both techniques will improve diagnosis in asymptomatic patients, allowing early therapeutic intervention and a better clinical outcome. 相似文献
940.
Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species 总被引:2,自引:0,他引:2 下载免费PDF全文
Carmen Sara Hernndez-Rodríguez Adri Van Vliet Nadine Bautsoens Jeroen Van Rie Juan Ferr 《Applied microbiology》2008,74(24):7654-7659
For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with 125I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera. Homologous-competition assays with 125I-Cry2Ab demonstrated that this toxin binds with high affinity to binding sites in H. armigera and Helicoverpa zea midgut. Heterologous-competition assays showed a common binding site for three toxins belonging to the Cry2A family (Cry2Aa, Cry2Ab, and Cry2Ae), which is not shared by Cry1Ac. Estimation of Kd (dissociation constant) values revealed that Cry2Ab had around 35-fold less affinity than Cry1Ac for BBMV binding sites in both insect species. Only minor differences were found regarding Rt (concentration of binding sites) values. This study questions previous interpretations from other authors performing binding assays with Cry2A toxins and establishes the basis for the mode of action of Cry2A toxins. 相似文献