Molecular docking studies of the antitumoral activity and characterization of new chalcone

Phytochemical investigation of Azorella madreporica led to the isolation of four known compounds and an unknown chalcone. The structure of the new compound was identified by spec-troscopy, including two-dimensional NMR techniques and comparison with published spectral data. The antioxidant ac-tivity of chalcone (compound 1) was measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scaveng-ing assay, and the bioactivity was evaluated against five bacteria (Mycobacterium smegmatis ATCC 14468, clinical iso-lates of Staphylococcus aureus, Klebsiella granulomatis, Morganella morganii and Escherichia coli) and four cancer cell lines. Docking studies with the tested cancer related proteins revealed nearby values of energy between doxorubicin and compound 1. Besides, protein-ligand interactions correlate with these energy value

Ski Is required for tri-methylation of H3K9 in major satellite and for repression of pericentromeric genes: Mmp3, Mmp10 and Mmp13, in mouse fibroblasts

Several mechanisms directing a rapid transcriptional reactivation of genes immediately after mitosis have been described. However, little is known about the maintenance of repressive signals during mitosis. In this work, we address the role of Ski in the repression of gene expression during M/G(1) transition in mouse embryonic fibroblasts (MEFs). We found that Ski localises as a distinct pair of dots at the pericentromeric region of mitotic chromosomes, and the absence of the protein is related to high acetylation and low tri-methylation of H3K9 in pericentromeric major satellite. Moreover, differential expression assays in early G(1) cells showed that the presence of Ski is significantly associated with repression of genes localised nearby to pericentromeric DNA. In mitotic cells, chromatin immunoprecipitation assays confirmed the association of Ski to major satellite and the promoters of the most repressed genes: Mmp3, Mmp10 and Mmp13. These genes are at pericentromeric region of chromosome 9. In these promoters, the presence of Ski resulted in increased H3K9 tri-methylation levels. This Ski-dependent regulation is also observed during interphase. Consequently, Mmp activity is augmented in Ski-/- MEFs. Altogether, these data indicate that association of Ski with the pericentromeric region of chromosomes during mitosis is required to maintain the silencing bookmarks of underlying chromatin.Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT) FONDECYT 1151435 1120222 PIA ACT172101 FONDAP 15090007 2111055

Sources of reactive nitrogen affecting ecosystems in Latin America and the Caribbean: current trends and future perspectives

While the amount of reactive nitrogen circulating at the global level has increased markedly in the last century, the effects of this increase are largely seen at the regional level due to interacting ecological and socio-economic factors. In contrast with most other regions of the world, Latin America and the Caribbean (LA-Ca) stand out due to the fact that the major input of reactive nitrogen (Nr) still occurs naturally via biological nitrogen fixation (BNF) in natural ecosystems as opposed to anthropogenic inputs of synthetic fertilizer, fossil fuel combustion and cropping with leguminous species. Largely due to economic reasons, the consumption of fertilizer N in the LA-Ca region is still low in comparison with the average consumption of the world. However, the fertilizer N consumption is increasing at a much faster rate than that in developed regions of the world, like USA and Canada. The Nr production through BNF in cultivated plants that fix nitrogen (C-BNF) is 5 times lower than that occurring naturally in Latin America, but is still equivalent to 16% of the world C-BNF. The cultivation of nitrogen-fixing crop species in the LA-Ca region is also increasing, almost entirely due to the expansion of soybean fields in the central and northern regions of Brazil and the Pampa region of Argentina. Other anthropogenic activities in the region that contribute to an increase in the circulation of reactive nitrogen include the impact of biomass burning and urbanization. In the last decade, an average of 47,000 km 2 per year of forests was burned in the LA-Ca region. The environmental impact of urban centers in the LA-Ca region has become very important, since an intense urbanization process is occurring in this region, at an intensity that far exceeds urban development in the northern hemisphere. The consequences of increased urbanization include increased emissions of NO x to the atmosphere due to the fossil fuel combustion, and the lack of sewage treatment facilities in most cities of the LA-Ca result in a large volume of untreated sewage discharged into surface waters, creating serious environmental problems. The combination of rapid urbanization and agricultural intensification in this region suggest that concern is warranted for the potential for increase in the circulation of reactive nitrogen in the very near future. At the same time, the opportunity still exists to mitigate some of the consequences of human impact on the nitrogen cycle in a region that still maintains a large fraction of its natural ecosystems intact.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46029/1/10533_2006_Article_9000.pd

A Latin American survey on demographic aspects of hospitalized, decompensated cirrhotic patients and the resources for their management

Introduction & objectives: Liver cirrhosis is a major cause of mortality worldwide. Adequate diagnosis and treatment of decompensating events requires of both medical skills and updated technical resources. The objectives of this study were to search the demographic profile of hospitalized cirrhotic patients in a group of Latin American hospitals and the availability of expertise/facilities for the diagnosis and therapy of decompensation episodes. Methods: A cross sectional, multicenter survey of hospitalized cirrhotic patients. Results: 377 patients, (62% males; 58 ± 11 years) (BMI > 25, 57%; diabetes 32%) were hospitalized at 65 centers (63 urbans; 57 academically affiliated) in 13 countries on the survey date. Main admission causes were ascites, gastrointestinal bleeding, hepatic encephalopathy and spontaneous bacterial peritonitis/other infections. Most prevalent etiologies were alcohol-related (AR) (40%); non-alcoholic-steatohepatitis (NASH) (23%), hepatitis C virus infection (HCV) (7%) and autoimmune hepatitis (AIH) (6%). The most frequent concurrent etiologies were AR + NASH. Expertise and resources in every analyzed issue were highly available among participating centers, mostly accomplishing valid guidelines. However, availability of these facilities was significantly higher at institutions located in areas with population > 500,000 (n = 45) and in those having a higher complexity level (Gastrointestinal, Liver and Internal Medicine Departments at the same hospital (n = 22). Conclusions: The epidemiological etiologic profile in hospitalized, decompensated cirrhotic patients in Latin America is similar to main contemporary emergent agents worldwide. Medical and technical resources are highly available, mostly at great population urban areas and high complexity medical centers. Main diagnostic and therapeutic approaches accomplish current guidelines recommendations