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101.
In the present study we intended to determine how BAT (brown adipose tissue) maintained thermogenesis under treatment with OE (oleoyl-oestrone), a powerful slimming hormone that sheds off body lipid but maintains the metabolic rate. Overweight male rats were subjected to daily gavages of 10 nmol/g of OE or vehicle (control) for 10 days. A PF (pair-fed) vehicle-receiving group was used to discount the effects attributable to energy availability limitation. Interscapular BAT mass, lipid, DNA, mRNA and the RT-PCR (real-time PCR) expression of lipid and energy metabolism genes for enzymes and regulatory proteins were measured. BAT mass and lipid were decreased in OE and PF, with the latter showing a marked reduction in tissue mRNA. Maintenance of perilipin gene expression in PF and OE rats despite the loss of lipid suggests the preservation of the vacuolar interactive surface, a critical factor for thermogenic responsiveness. OE and, to a lesser extent, PF maintained the expression of genes controlling lipolysis and fatty acid oxidation, but markedly decreased the expression of those genes involved in lipogenic and acyl-glycerol synthesis. OE did not affect UCP1 (uncoupling protein 1) (decreased in PF), beta(3) adrenergic receptors or hormone-sensitive lipase gene mRNAs, which may translate in maintaining a full thermogenic system potential. OE rats were able to maintain a less energetically stressed BAT (probably through glucose utilization) than PF rats. These changes were not paralleled in PF rats, in which lower thermogenesis and glucose preservation resulted in a heavier toll on internal fat stores. Thus the mechanism of action of OE is more complex and tissue-specific than previously assumed. 相似文献
102.
Benigno Padrón Anna Traveset Tine Biedenweg Diana Díaz Manuel Nogales Jens M. Olesen 《PloS one》2009,4(7)
Mutualistic interactions between plants and animals promote integration of invasive species into native communities. In turn, the integrated invaders may alter existing patterns of mutualistic interactions. Here we simultaneously map in detail effects of invaders on parameters describing the topology of both plant-pollinator (bi-modal) and plant-plant (uni-modal) networks. We focus on the invader Opuntia spp., a cosmopolitan alien cactus. We compare two island systems: Tenerife (Canary Islands) and Menorca (Balearic Islands). Opuntia was found to modify the number of links between plants and pollinators, and was integrated into the new communities via the most generalist pollinators, but did not affect the general network pattern. The plant uni-modal networks showed disassortative linkage, i.e. species with many links tended to connect to species with few links. Thus, by linking to generalist natives, Opuntia remained peripheral to network topology, and this is probably why native network properties were not affected at least in one of the islands. We conclude that the network analytical approach is indeed a valuable tool to evaluate the effect of invaders on native communities. 相似文献
103.
Background
Biomass has been studied as biomarker to evaluate the effect of heavy metals on microbial communities. Nevertheless, the most important methodological problem when working with natural and artificial microbial mats is the difficulty to evaluate changes produced on microorganism populations that are found in thicknesses of just a few mm depth.Methodology/Principal Findings
Here, we applied for first time a recently published new method based on confocal laser scanning microscopy and image-program analysis to determine in situ the effect of Pb and Cu stress in cyanobacterial populations.Conclusions/Significance
The results showed that both in the microcosm polluted by Cu and by Pb, a drastic reduction in total biomass for cyanobacterial and Microcoleus sp. (the dominant filamentous cyanobacterium in microbial mats) was detected within a week. According to the data presented in this report, this biomass inspection has a main advantage: besides total biomass, diversity, individual biomass of each population and their position can be analysed at microscale level. CLSM-IA could be a good method for analyzing changes in microbial biomass as a response to the addition of heavy metals and also to other kind of pollutants. 相似文献104.
Esteve Fernández Marcela Fu José A. Pascual María J. López Mónica Pérez-Ríos Anna Schiaffino Jose M. Martínez-Sánchez Carles Ariza Esteve Saltó Manel Nebot and the Spanish Smoking Law Evaluation Group 《PloS one》2009,4(1)
Background
A smoke-free law came into effect in Spain on 1st January 2006, affecting all enclosed workplaces except hospitality venues, whose proprietors can choose among totally a smoke-free policy, a partial restriction with designated smoking areas, or no restriction on smoking on the premises. We aimed to evaluate the impact of the law among hospitality workers by assessing second-hand smoke (SHS) exposure and the frequency of respiratory symptoms before and one year after the ban.Methods and Finding
We formed a baseline cohort of 431 hospitality workers in Spain and 45 workers in Portugal and Andorra. Of them, 318 (66.8%) were successfully followed up 12 months after the ban, and 137 nonsmokers were included in this analysis. We obtained self-reported exposure to SHS and the presence of respiratory symptoms, and collected saliva samples for cotinine measurement. Salivary cotinine decreased by 55.6% after the ban among nonsmoker workers in venues where smoking was totally prohibited (from median of 1.6 ng/ml before to 0.5 ng/ml, p<0.01). Cotinine concentration decreased by 27.6% (p = 0.068) among workers in venues with designated smoking areas, and by 10.7% (p = 0.475) among workers in venues where smoking was allowed. In Portugal and Andorra, no differences between cotinine concentration were found before (1.2 ng/ml) and after the ban (1.2 ng/ml). In Spain, reported respiratory symptom declined significantly (by 71.9%; p<0.05) among workers in venues that became smoke-free. After adjustment for potential confounders, salivary cotinine and respiratory symptoms decreased significantly among workers in Spanish hospitality venues where smoking was totally banned.Conclusions
Among nonsmoker hospitality workers in bars and restaurants where smoking was allowed, exposure to SHS after the ban remained similar to pre-law levels. The partial restrictions on smoking in Spanish hospitality venues do not sufficiently protect hospitality workers against SHS or its consequences for respiratory health. 相似文献105.
106.
In recent years, the function of different tumour suppressors in the regulation of macroautophagy has been studied. We show here that BRCA1, unlike other tumour suppressors, negatively regulates formation of autophagosomes and lysosomal mass under conditions of both basal and enhanced autophagy. In MCF-7 breast cancer cells, increased formation of autophagic vacuoles after inactivation of BRCA1 by siRNAs is associated with an increase in reactive oxygen species, such as superoxide anion and hydrogen peroxide. This allows one to propose an antioxidant function for BRCA1 and suggests that dysfunctional mitochondria and the generated reactive oxygen species excess could explain the increased macroautophagy observed in the absence of BRCA1. In addition, a quick decrease in BRCA1 levels occurs when MCF-7 cells are switched to a nutrient-poor environment that stimulates macroautophagy and that is also reminiscent of certain phases of tumour growth. Inhibition of BRCA1 synthesis has an important role in this reduction, while there are almost no changes in BRCA1 degradation by lysosomes and proteasomes. Therefore, BRCA1 produces macroautophagy inhibition by reducing the formation of autophagic vacuoles, and this, together with the other results presented here, shows new functional aspects of BRCA1 that could help to clarify the role of autophagy in cancer development. 相似文献
107.
Celina García Leticia G. León Carlos R. Pungitore Carla Ríos-Luci Antonio H. Daranas Juan C. Montero Atanasio Pandiella Carlos E. Tonn Víctor S. Martín José M. Padrón 《Bioorganic & medicinal chemistry》2010,18(7):2515-2523
Two iridoid scaffolds were synthesized enantioselectively using as key step an l-proline-catalyzed α-formyl oxidation. The in vitro antiproliferative activities were evaluated against a representative panel of human solid tumor cell lines. Both iridoids induced considerably growth inhibition in the range 0.38–1.86 μM. Cell cycle studies for these compounds showed the induction of cell cycle arrest at the G1 phase. This result was consistent with a decrease in the expression of cyclin D1. Damaged cells underwent apoptosis as indicated by specific Annexin V staining. 相似文献
108.
Martínez-Sánchez JM Fernández E Fu M Gallus S Martínez C Sureda X La Vecchia C Clancy L 《PloS one》2010,5(11):e13881
Background
The six most important cost-effective policies on tobacco control can be measured by the Tobacco Control Scale (TCS). The objective of our study was to describe the correlation between the TCS and smoking prevalence, self-reported exposure to secondhand smoke (SHS) and attitudes towards smoking restrictions in the 27 countries of the European Union (EU27).Methods/Principal Findings
Ecologic study in the EU27. We used data from the TCS in 2007 and from the Eurobarometer on Tobacco Survey in 2008. We analysed the relations between the TCS and prevalence of smoking, self-reported exposure to SHS (home and work), and attitudes towards smoking bans by means of scatter plots and Spearman rank-correlation coefficients (rsp). Among the EU27, smoking prevalence varied from 22.6% in Slovenia to 42.1% in Greece. Austria was the country with the lowest TCS score (35) and the UK had the highest one (93). The correlation between smoking prevalence and TCS score was negative (rsp = −0.42, p = 0.03) and the correlation between TCS score and support to smoking bans in all workplaces was positive (rsp = 0.47, p = 0.01 in restaurants; rsp = 0.5, p = 0.008 in bars, pubs, and clubs; and rsp = 0.31, p = 0.12 in other indoor workplaces). The correlation between TCS score and self-reported exposure to SHS was negative, but statistically non-significant.Conclusions/Significance
Countries with a higher score in the TCS have higher support towards smoking bans in all workplaces (including restaurants, bars, pubs and clubs, and other indoor workplaces). TCS scores were strongly, but not statistically, associated with a lower prevalence of smokers and a lower self-reported exposure to SHS. 相似文献109.
Badimon L Martínez-González J Llorente-Cortés V Rodríguez C Padró T 《Current molecular medicine》2006,6(5):439-456
Atherosclerosis is an inflammatory process, triggered by the presence of lipids in the vascular wall, and encompasses a complex interaction among inflammatory cells, vascular elements, and lipoproteins through expression of several adhesion molecules and cytokines. Subendothelial retention of lipoproteins is the key initiating event in atherosclerosis, provoking a cascade of events to pathogenic response. High levels of plasma lipids, particularly low-density (LDL) and very-low-density lipoproteins (VLDL) are among the pathophysiologic stimuli that induce endothelial dysfunction. Endothelial cells regulate coagulation, thrombosis and the fibrinolytic system; the endothelium modulates the activity of smooth muscle cells (vascular tone/proliferation) and controls the traffic of macromolecules and inflammatory cells to the vessel wall. Furthermore, LDLs have been implicated in the induction of changes in permeability, cell adhesion and secretion of vasoactive molecules (nitric oxide [NO]), while VLDLs seem to modulate the fibrinolytic system [tissue plasminogen activator (TPA) and plasminogen activator inhibitor-1 (PAI-1)]. In this review, we will focus on the pathophysiologic functions of lipoproteins in the vascular wall. 相似文献
110.
Fombonne J Padrón L Enjalbert A Krantic S Torriglia A 《Apoptosis : an international journal on programmed cell death》2006,11(3):367-375
We have recently reported that EGF triggers an original form of cell death in pituitary cell line (GH4C1) with a phenotype
sharing some characteristics of both apoptosis (internucleosomal DNA fragmentation) and paraptosis (caspase-independence and
cytoplasmic vacuolization). However, the endonuclease involved in EGF-induced DNA fragmentation has not been assessed so far.
In the present work we therefore further explored the putative paraptosis involvement in EGF-induced cell death and asked
whether L-DNaseII might be involved. Indeed, this endonuclease is known to mediate internucleosomal DNA fragmentation in caspase
independent manner. Our Western blot, immunocytochemistry and enzymatic measurement assays show that EGF triggers a cleavage
of Leukocyte Elastase Inhibitor (LEI) precursor into L-DNaseII, its subsequent enzymatic activation and nuclear translocation
thus pointing to the involvement of this endonuclease pathway in caspase-independent DNA fragmentation. In addition, EGF-induced
cell death can be blocked by paraptosis inhibitor AIP-1/Alix, but not with its anti-apoptotic C-terminal fragment (Alix-CT).
Altogether these data suggest that EGF-induced cell death defines a novel, L-DNaseII-mediated form of paraptosis.
This work was supported by fellowships from Fondation pour la Recherche medicale (FRM: FDT20030627283), from Association pour
la Recherche contre le Cancer (ARC: ML/MLD/CM-A04/4) to JF and Retina France to AT and LP.
These two authors equally contributed to this work. 相似文献