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191.
Vasodilator effects of peptides derived from egg white proteins 总被引:1,自引:0,他引:1
The aim of this work was to investigate the effect of several peptides, identified before and after simulated gastrointestinal digestion of an egg white hydrolysate, on the vascular function, in rat aorta. The sequences IVF, RADHPFL and YAEERYPIL (0.1 mM) induced vasodilatation in intact aortic rings, with the maximum percentage of dilation corresponding to RADHPFL (40.5 ± 7.0%). Two of the end products of the gastrointestinal digestion, RADHP and YPI, also showed vasodilator activity with degrees of relaxation higher than 50%. However, all these peptides failed to induce relaxation in endothelium-denuded aortic rings. The relaxation induced by RADHP was concentration-dependent and it was partially blocked by the nitric oxide synthase inhibitor l-NAME (100 μM) and by the B1 bradykinin receptor antagonist Des-HOE 140 (30 nM), thus showing that it was mediated by NO production through the activation of B1 bradykinin receptors. These findings suggest that these peptides could reduce the vascular resistance and could be used as functional food ingredients in the prevention and treatment of hypertension. 相似文献
192.
The zero-sum assumption in neutral biodiversity theory 总被引:5,自引:1,他引:4
The neutral theory of biodiversity as put forward by Hubbell in his 2001 monograph has received much criticism for its unrealistic simplifying assumptions. These are the assumptions of functional equivalence among different species (neutrality), the assumption of point mutation speciation, and the assumption that resources are continuously saturated, such that constant resource availability implies constant community size (zero-sum assumption). Here we focus on the zero-sum assumption. We present a general theory for calculating the probability of observing a particular species-abundance distribution (sampling formula) and show that zero-sum and non-zero-sum formulations of neutral theory have exactly the same sampling formula when the community is in equilibrium. Moreover, for the non-zero-sum community the sampling formula has this same form, even out of equilibrium. Therefore, the term "zero-sum multinomial (ZSM)" to describe species abundance patterns, as coined by Hubbell [2001. The Unified Neutral Theory of Biodiversity and Biogeography, Princeton University Press, Princeton, NJ], is not really appropriate, as it also applies to non-zero-sum communities. Instead we propose the term "dispersal-limited multinomial (DLM)", thus making explicit one of the most important contributions of neutral community theory, the emphasis on dispersal limitation as a dominant factor in determining species abundances. 相似文献
193.
A cDNA that encodes a transporter from the NHAD family was identified in Physcomitrella patens. Computer-based searches using the amino acid sequence of PpNHAD1 revealed that, in addition to being expressed in flowering plants, highly conserved transporters of this family are expressed in red algae, green algae, mosses, liverworts, and photosynthetic stramenopiles, but not in heterotrophic stramenopiles. A chloroplast transit peptide was detected in PpNHAD1 and in most of the related sequences, indicating that PpNHAD1 is a chloroplast transporter. A PpNHAD1-GFP fusion localized to the chloroplast in Physcomitrella protoplasts, and truncation of the N-terminus of the protein dispersed the fluorescence signal outside the chloroplast. PpNHAD1 did not show functional expression in either yeast or bacterial mutants, but truncated proteins with shorter N-termini, PpNHAD1-1 and PpNHAD1-2, could be functionally expressed in bacteria. PpNHAD1-1 alleviated the Li(+) intolerance of a Na(+)-efflux Escherichia coli mutant at acidic pH values. Both PpNHAD1-1 and PpNHAD1-2 reduced the K(+) requirements of a K(+)-influx E. coli mutant more actively at high pH values. PpNHAD1 seems to be an important transporter that mediates ionic homeostasis in chloroplasts from red algae to flowering plants. 相似文献
194.
RAB23 mutations in Carpenter syndrome imply an unexpected role for hedgehog signaling in cranial-suture development and obesity 总被引:2,自引:0,他引:2
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Jenkins D Seelow D Jehee FS Perlyn CA Alonso LG Bueno DF Donnai D Josifova D Josifiova D Mathijssen IM Morton JE Orstavik KH Sweeney E Wall SA Marsh JL Nurnberg P Passos-Bueno MR Wilkie AO 《American journal of human genetics》2007,80(6):1162-1170
Carpenter syndrome is a pleiotropic disorder with autosomal recessive inheritance, the cardinal features of which include craniosynostosis, polysyndactyly, obesity, and cardiac defects. Using homozygosity mapping, we found linkage to chromosome 6p12.1-q12 and, in 15 independent families, identified five different mutations (four truncating and one missense) in RAB23, which encodes a member of the RAB guanosine triphosphatase (GTPase) family of vesicle transport proteins and acts as a negative regulator of hedgehog (HH) signaling. In 10 patients, the disease was caused by homozygosity for the same nonsense mutation, L145X, that resides on a common haplotype, indicative of a founder effect in patients of northern European descent. Surprisingly, nonsense mutations of Rab23 in open brain mice cause recessive embryonic lethality with neural-tube defects, suggesting a species difference in the requirement for RAB23 during early development. The discovery of RAB23 mutations in patients with Carpenter syndrome implicates HH signaling in cranial-suture biogenesis--an unexpected finding, given that craniosynostosis is not usually associated with mutations of other HH-pathway components--and provides a new molecular target for studies of obesity. 相似文献
195.
Harrelson JP Henne KR Alonso DO Nelson SD 《Biochemical and biophysical research communications》2007,352(4):843-849
Considering the dynamic nature of CYPs, methods that reveal information about substrate and enzyme dynamics are necessary to generate predictive models. To compare substrate dynamics in CYP2E1 and CYP2A6, intramolecular isotope effect experiments were conducted, using deuterium labeled substrates: o-xylene, m-xylene, p-xylene, 2,6-dimethylnaphthalene, and 4,4'-dimethylbiphenyl. Competitive intermolecular experiments were also conducted using d(0)- and d(6)-labeled p-xylene. Both CYP2E1 and CYP2A6 displayed full isotope effect expression for o-xylene oxidation and almost complete suppression for dimethylbiphenyl. Interestingly, (k(H)/k(D))(obs) for d(3)-p-xylene oxidation ((k(H)/k(D))(obs)=6.04 and (k(H)/k(D))(obs)=5.53 for CYP2E1 and CYP2A6, respectively) was only slightly higher than (k(H)/k(D))(obs) for d(3)-dimethylnaphthalene ((k(H)/k(D))(obs)=5.50 and (k(H)/k(D))(obs)=4.96, respectively). One explanation is that in some instances (k(H)/k(D))(obs) values are generated by the presence of two substrates-bound simultaneously to the CYP. Speculatively, if this explanation is valid, then intramolecular isotope effect experiments should be useful in the mechanistic investigation of P450 cooperativity. 相似文献
196.
Plant phenology is in great measure driven by air temperature. To forecast harvest time for ‘Algerie’ loquat accurately, the
growing degree days (GDD) needed from bloom to ripening were determined using data from nine seasons. The methods proposed
by Zalom et al. (Zalom FG, Goodell PB, Wilson LT, Barnett WW, Bentley W, Degree-days: the calculation and use of heat units
in pest management, leaflet no 21373, Division Agriculture and Natural Resources, University of California 10 pp, 1983) were compared as regards their ability to estimate heat summation based on hourly records. All the methods gave remarkably
similar results for our cultivation area, although the double-sine method showed higher performance when temperatures were
low. A base temperature of 3°C is proposed for ‘Algerie’ loquat because it provides a coefficient of variation in GDD among
seasons of below 5%, and because of its compatibility with loquat growth. Based on these determinations, ‘Algerie’ loquat
requires 1,715 GDD from bloom to harvest; under our conditions this heat is accumulated over an average of 159 days. Our procedure
permits the ‘Algerie’ harvest date to be estimated with a mean error of 4.4 days (<3% for the bloom-harvest period). GDD summation
did not prove superior to the use of the number of calendar days for predicting ‘Algerie’ harvest under non-limiting growing
conditions. However, GDD reflects the developmental rate in water-stressed trees better than calendar days. Trees under deficit
irrigation during flower development required more time and more heat to ripen their fruits. 相似文献
197.
T cells are crucial for the anti-metastatic effect of anti-epidermal growth factor receptor antibodies 总被引:2,自引:0,他引:2
Garrido G Lorenzano P Sánchez B Beausoleil I Alonso DF Pérez R Fernández LE 《Cancer immunology, immunotherapy : CII》2007,56(11):1701-1710
Experimental evidences supporting the epidermal growth factor receptor (EGFR) as an important molecule for tumor metastasis
had been accumulated. Currently, anti-EGFR monoclonal antibodies (mAbs) constitute a promising approach for the treatment
of patients with metastatic tumors. However, the mechanisms associated with the potent anti-metastatic effect of these mAbs
have not been completely elucidated due to the lack of appropriate syngeneic preclinical models. In this paper, we have investigated
the effects of 7A7, an antibody specific to murine EGFR, on the metastatic properties of D122 murine lung carcinoma. 7A7 mAb
significantly impaired metastatic spread of D122 cells in C57BL/6 mice by direct anti-proliferative and pro-apoptotic effects
on tumor metastasis. 7A7 mAb capacity to inhibit EGFR activation on D122 cells could contribute to its anti-metastatic effect.
In addition, 7A7 mAb was able to induce in vitro antibody-dependent cell-mediated cytotoxicity on D122 cells. Interestingly,
7A7 mAb treatment increased the number of natural killer cells, T lymphocytes and dendritic cells infiltrating the metastatic
sites. More strikingly, depletion of CD8+ and CD4+ T cells in vivo completely abrogated the 7A7 mAb anti-metastatic activity whereas function of natural killer cells was irrelevant.
This study supports an in vivo role for T cell response in the mechanism of action of anti-EGFR mAbs, suggesting the induction
of an adjuvant effect.
This work was supported by the Cuban Government. 相似文献
198.
199.
Yamile Gonzlez Aparecida S. Tanaka Izaura Y. Hirata Maday Alonso del Rivero Maria L.V. Oliva Mariana S. Araujo Maria A. Chvez 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,146(4):506
Human neutrophil elastase inhibition was detected in a crude extract of the marine snail Cenchritis muricatus (Gastropoda, Mollusca). This inhibitory activity remained after heating this extract at 60 °C for 30 min. From this extract, three human neutrophil elastase inhibitors (designated CmPI–I, CmPI–II and CmPI–III) were purified by affinity and reversed-phase chromatographies. Homogeneity of CmPI–I and CmPI–II was confirmed, while CmPI–III showed a single peak in reversed-phase chromatography, but heterogeneity in SDS-PAGE with preliminary molecular masses in the range of 18.4 to 22.0 kDa. In contrast, MALDI-TOF mass spectrometry of CmPI–I and CmPI–II showed that these inhibitors are molecules of low molecular mass, 5576 and 5469 Da, respectively. N-terminal amino acid sequences of CmPI–I (6 amino acids) and CmPI–II (20 amino acids) were determined. Homology to Kazal-type protease inhibitors was preliminarily detected for CmPI–II. Both inhibitors, CmPI–I and CmPI–II are able to inhibit human neutrophil elastase strongly, with equilibrium dissociation constant (Ki) values of 54.2 and 1.6 nM, respectively. In addition, trypsin and pancreatic elastase were also inhibited, but not plasma kallikrein or thrombin. CmPI–I and CmPI–II are the first human neutrophil elastase inhibitors described in a mollusk. 相似文献
200.
Occupational exposure to airborne fungi and bacteria in a household recycled container sorting plant
Several studies have showed an association between the work in waste treatment plants and occupational health problems such as irritation of skin, eyes and mucous membranes, pulmonary diseases, gastrointestinal problems and symptoms of organic dust toxic syndrome (ODTS). These symptoms have been related to bioaerosol exposure. The aim of this study was to investigate the occupational exposure to biological agents in a plant sorting source-separated packages (plastics materials, ferric and non-ferric metals) household waste. Airborne samples were collected with M Air T Millipore sampler. The concentration of total fungi and bacteria and gram-negative bacteria were determined and the most abundant genera were identified. The results shown that the predominant airborne microorganisms were fungi, with counts greater than 12,000 cfu/m(3) and gram-negative bacteria, with a environmental concentration between 1,395 and 5,280 cfu/m(3). In both cases, these concentrations were higher than levels obtained outside of the sorting plant. Among the fungi, the predominant genera were Penicillium and Cladosporium, whereas the predominant genera of gram-negative bacteria were Escherichia, Enterobacter, Klebsiella and Serratia. The present study shows that the workers at sorting source-separated packages (plastics materials, ferric and non-ferric metals) domestic waste plant may be exposed to airborne biological agents, especially fungi and gram-negative bacteria. 相似文献