145 resultados para CLEAVAGE SITES
Resumo:
Secretory leucoprotease inhibitor (SLPI) is a nonglycosylated protein produced by epithelial cells. In addition to its antiprotease activity, SLPI has been shown to exhibit antiinflammatory properties, including down-regulation of tumor necrosis factor alpha expression by lipopolysaccharide (LPS) in macrophages and inhibition of nuclear factor (NF)-kappaB activation in a rat model of acute lung injury. We have previously shown that SLPI can inhibit LPS-induced NF-kappaB activation in monocytic cells by inhibiting degradation of IkappaBalpha without affecting the LPS-induced phosphorylation and ubiquitination of IkappaBalpha. Here, we present evidence to show that upon incubation with peripheral blood monocytes (PBMs) and the U937 monocytic cell line, SLPI enters the cells, becoming rapidly localized to the cytoplasm and nucleus, and affects NF-kappaB activation by binding directly to NF-kappaB binding sites in a site-specific manner. SLPI can also prevent p65 interaction with the NF-kappaB consensus region at concentrations commensurate with the physiological nuclear levels of SLPI and p65. We also demonstrate the presence of SLPI in nuclear fractions of PBMs and alveolar macrophages from individuals with cystic fibrosis and community-acquired pneumonia. Therefore, SLPI inhibition of NF-kappaB activation is mediated, in part, by competitive binding to the NF-kappaB consensus-binding site.
Resumo:
Elafin is a 6-kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases [neutrophil elastase (NE) and proteinase 3] with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), are able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaves elafin at the amino-terminal Lys6-Gly7 peptide bond, resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidence that elafin is susceptible to proteolytic cleavage at alternative sites by P aeruginosa metalloproteinases, which can affect different biological functions of elafin.
Proteolytic cleavage of elafin by 20S proteasome may contribute to inflammation in acute lung injury
Resumo:
RATIONALE:
We hypothesise that elafin levels in acute lung injury (ALI) decrease over time due, in part, to proteolytic degradation as observed in other lung diseases.
OBJECTIVES:
The aim of this study was to characterise temporal changes in elafin concentration in patients with ALI and to evaluate whether a decrease in elafin levels is due to elevated protease activity.
METHODS:
Bronchoalveolar lavage fluid (BALF) was obtained from patients with ALI within 48 h of onset of ALI (day 0), at day 3 and at day 7. Elafin levels were quantified by ELISA. Elafin susceptibility to proteolytic cleavage by ALI BALF was assessed by Western blot and by high-performance liquid chromatography-mass spectrometry.
MEASUREMENTS AND MAIN RESULTS:
Elafin levels were found to be significantly increased at the onset of ALI compared with healthy volunteers and fell significantly by day 7 compared with day 0. In contrast, levels of secretory leukocyte protease inhibitor did not decrease over time. This decrease in elafin was due to cleavage by the 20S proteasome which was significantly increased in ALI BALF. Incubation of ALI BALF with the proteasome inhibitor epoxomicin confirmed that 20S proteasome protease activity was responsible for proteolytic cleavage of elafin, resulting in diminished anti-elastase activity. In addition, free neutrophil elastase activity significantly increased in ALI BALF from day 0 to day 7.
CONCLUSIONS:
Elafin concentrations fall within the pulmonary compartment over the course of ALI as a result of proteolytic degradation. This loss of elafin may predispose people, in part, to excessive inflammation in ALI.
Resumo:
• Inorganic arsenic (As(i) ) in rice (Oryza sativa) grains is a possible threat to human health, with risk being strongly linked to total dietary rice consumption and consumed rice As(i) content. This study aimed to identify the range and stability of genetic variation in grain arsenic (As) in rice. • Six field trials were conducted (one each in Bangladesh and China, two in Arkansas, USA over 2 yr, and two in Texas, USA comparing flooded and nonflood treatments) on a large number of common rice cultivars (c. 300) representing genetic diversity among international rice cultivars. • Within each field there was a 3-34 fold range in grain As concentration which varied between rice subpopulations. Importantly, As(i) correlated strongly with total As among a subset of 40 cultivars harvested in Bangladesh and China. • Genetic variation at all field sites was a large determining factor for grain As concentration, indicating that cultivars low in grain As could be developed through breeding. The temperate japonicas exhibited lower grain As compared with other subpopulations. Effects for year, location and flooding management were also statistically significant, suggesting that breeding strategies must take into account environmental factors.
Resumo:
The concentration of arsenic (As) in rice grains has been identified as a risk to human health. The high proportion of inorganic species of As (As(i)) is of particular concern as it is a nonthreshold, class 1 human carcinogen. To be able to breed rice with low grain As, an understanding of genetic variation and the effect of different environments on genetic variation is needed. In this study, 13 cultivars grown at two field sites each in Bangladesh, India, and China are evaluated for grain As. There was a significant site, genotype, and site by genotype interaction for total grain As. Correlations were observed only between sites in Bangladesh and India, not between countries or within the Chinese sites. For seven cultivars the As was speciated which revealed significant effects of site, genotype, and site by genotype interaction for percentage As(i). Breeding low grain As cultivars that will have consistently low grain As and low As(i), over multiple environments using traditional breeding approaches may be difficult, although CT9993-5-10-1-M, Lemont, Azucena, and Te-qing in general had low grain As across the field sites.
Resumo:
Arsenic can be highly toxic to mammals but there is relatively little information on its transfer to and uptake by free-living small mammals. The aim of this study was to determine whether intake and accumulation of arsenic by wild rodents living in arsenic-contaminated habitats reflected environmental levels of contamination and varied between species, sexes and age classes. Arsenic concentrations were measured in soil, litter, wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from six sites which varied in the extent to which they were contaminated. Arsenic residues on the most contaminated sites were three and two orders of magnitude above background in soil and litter, respectively. Arsenic concentrations in the stomach contents, liver, kidney and whole body of small mammals reflected inter-site differences in environmental contamination. Wood mice and bank voles on the same sites had similar concentrations of arsenic in their stomach contents and accumulated comparable residues in the liver, kidney and whole body. Female bank voles, but not wood mice, had significantly higher stomach content and liver arsenic concentrations than males. Arsenic concentration in the stomach contents and body tissues did not vary with age class. The bioaccumulation factor (ratio of arsenic concentration in whole body to that in the diet) in wood mice was not significantly different to that in bank voles and was 0.69 for the two species combined, indicating that arsenic was not bioconcentrated in these rodents. Overall, this study has demonstrated that adult and juvenile wood mice and bank voles are exposed to and accumulate similar amounts of arsenic on arsenic-contaminated mine sites and that the extent of accumulation depends upon the level of habitat contamination.
Resumo:
A series of iron containing zeolites with varying Si/Al ratios (11.5-140) and low iron content (similar to 0.9 wt.% Fe) have been synthesised by solid-state ion exchange with commercially available zeolites and tested, for the first time, in the oxidative dehydrogenation of propane (ODHP) with N2O. The samples were characterised by XRD, N-2-Adsorption, NH3-TPD and DR-UV-vis spectroscopy. The acidity of the Fe-ZSM-5 can be controlled by high temperature and steam treatments and Si/Al ratio. The selectivity and yield of propene were found to be the highest over Fe-ZSM-5 with low Al contents and reduced acidity. The initial propene yield over Fe-ZSM-5 was significantly higher than that of Fe-SiO2 since the presence of weak and/or medium acid sites together with oligonuclear iron species and iron oxides on the ZSM-5 are found to enhance the N2O activation. The coking of Fe-ZSM-5 catalysts could also be controlled by reduction of the surface acidity of ZSM-5 and by the use of O-2 in addition to N2O as the oxidant. Fe-ZSM-5 zeolites prepared with solid-state method have been shown to have comparable activity and better stability towards coking compared with Fe-ZSM-5 zeolites prepared by liquid ion exchange and hydrothermal synthesis methods. (C) 2012 Elsevier B.V. All rights reserved.
Resumo:
We use conjoint choice questions to investigate people's tastes for cancer risk reductions and income in the context of public programs that would provide for remediation at abandoned industrial contaminated sites. Our survey was self-administered using the computer by persons living in the vicinity of an important contaminated site on the Italian National Priority List. The value of a prevented case of cancer is €2.6 million, but this figure does vary with income, perceived exposure to contaminants, and respondent opinions about priorities that should be pursued by cleanup programs. © 2011 Society for Risk Analysis.
Resumo:
Selection of sites for successful restoration of impacted shellfish populations depends on understanding the dispersion capability and habitat requirements of the species involved. In Strangford Lough, Northern Ireland, the horse mussel (Modiolus modiolus) biogenic reefs cover only a fraction of their historical range with the remaining reefs badly damaged and requiring restoration. Previous experimental trials suggest that translocation of horse mussels accelerates reef recovery and has therefore been proposed as a suitable restoration technique. We used a series of coupled hydrodynamic and particle dispersal models to assess larval dispersion from remnant and translocated populations to identify suitable areas for adult live M. modiolus translocation in Strangford Lough, Northern Ireland. A maximum entropy model (MAXENT) was used to identify if dispersing larvae could reach habitat suitable for adult M. modiolus. From these we predicted if translocated mussels will reseed themselves or be able to act as larval sources for nearby reefs. The dispersal models showed that the remnant M. modiolus populations are largely self-recruiting with little connectivity between them. The majority of larvae settled near the sources and movement was largely dependent on the tides and not influenced by wind or waves. Higher reef elevation resulted in larvae being able to disperse further away from the release point. However, larval numbers away from the source population are likely to be too low for successful recruitment. There was also little connectivity between the Irish Sea and Strangford Lough as any larvae entering the Lough remained predominantly in the Strangford Narrows. The areas covered by these self-seeding populations are suitable for M. modiolus translocation according to the MAXENT model. As a result of this work and in conjunction with other field work we propose a combination of total protection of all remaining larval sources and small scale translocations onto suitable substrata in each of the identified self-recruiting areas.
Resumo:
REMA is an interactive web-based program which predicts endonuclease cut sites in DNA sequences. It analyses Multiple sequences simultaneously and predicts the number and size of fragments as well as provides restriction maps. The users can select single or paired combinations of all commercially available enzymes. Additionally, REMA permits prediction of multiple sequence terminal fragment sizes and suggests suitable restriction enzymes for maximally discriminatory results. REMA is an easy to use, web based program which will have a wide application in molecular biology research. Availability: REMA is written in Perl and is freely available for non-commercial use. Detailed information on installation can be obtained from Jan Szubert (jan.szubert@gmail.com) and the web based application is accessible on the internet at the URL http://www.macaulay.ac.uk/rema. Contact: b.singh@macaulay.ac.uk. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
Plant embryogenesis is intimately associated with programmed cell death. The mechanisms of initiation and control of programmed cell death during plant embryo development are not known. Proteolytic activity associated with caspase-like proteins is paramount for control of programmed cell death in animals and yeasts. Caspase family of proteases has unique strong preference for cleavage of the target proteins next to asparagine residue. In this work, we have used synthetic peptide substrates containing caspase recognition sites and corresponding specific inhibitors to analyse the role of caspase-like activity in the regulation of programmed cell death during plant embryogenesis. We demonstrate that VEIDase is a principal caspase-like activity implicated in plant embryogenesis. This activity increases at the early stages of embryo development that coincide with massive cell death during shape remodeling. The VEIDase activity exhibits high sensitivity to pH, ionic strength and Zn2+ concentration. Altogether, biochemical assays show that VEIDase plant caspase-like activity resembles that of both mammalian caspase-6 and yeast metacaspase, YCA1. In vivo, VEIDase activity is localised specifically in the embryonic cells during both the commitment and in the beginning of the execution phase of programmed cell death. Inhibition of VEIDase prevents normal embryo development via blocking the embryo-suspensor differentiation. Our data indicate that the VEIDase activity is an integral part in the control of plant developmental cell death programme, and that this activity is essential for the embryo pattern formation.
Resumo:
Objective. To investigate students' use and views on social networking sites and assess differences in attitudes between genders and years in the program.
Methods. All pharmacy undergraduate students were invited via e-mail to complete an electronic questionnaire consisting of 21 questions relating to social networking.
Results. Most (91.8%) of the 377 respondents reported using social networking Web sites, with 98.6% using Facebook and 33.7% using Twitter. Female students were more likely than male students to agree that they had been made sufficiently aware of the professional behavior expected of them when using social networking sites (76.6% vs 58.1% p=0.002) and to agree that students should have the same professional standards whether on placement or using social networking sites (76.3% vs 61.6%; p<0.001).
Conclusions. A high level of social networking use and potentially inappropriate attitudes towards professionalism were found among pharmacy students. Further training may be useful to ensure pharmacy students are aware of how to apply codes of conduct when using social networking sites.
Resumo:
2010-12 Expert Assistance with research material, digital illustration and text for Visitor Centres in Malta and Gozo (Heritage Malta) and National Museum
Resumo:
Hodder, I. and C.A.T. Malone, . Proceedings of the Prehistoric Society