Quinones bearing non-steroidal anti-inflammatory fragments as multitarget ligands for Alzheimer’s disease

The anti-amyloid properties shared by several quinones inspired the design of a new series of hybrids derived from the multi-target drug candidate memoquin (1). The hybrids consist of a central benzoquinone core and a fragment taken from non-steroidal anti-inflammatory drugs, connected through polyamine linkers. The new hybrids retain the potent anti-aggregating activity of the parent 1, while exhibiting micromolar AChE inhibitory activities. Remarkably, 2, 4, (R)-6 and (S)-6 were Aβ aggregation inhibitors even more potent than 1. The balanced amyloid/cholinesterase inhibitory profile is an added value that makes the present series of compounds promising leads against Alzheimer’s disease.     

Kinetic and anion inhibition studies of a β-carbonic anhydrase (FbiCA 1) from the C4 plant Flaveria bidentis

Several β-carbonic anhydrases (CAs, EC 4.2.1.1) are present in all land plants examined thus far. Here we report the first detailed biochemical characterization of one such isoform, FbiCA 1, from the C₄ plant Flaveria bidentis, which was cloned, purified and characterized as recombinant protein. FbiCA 1 has an interesting CO₂ hydrase catalytic activity (k_cat of 1.2 × 10⁵ and k_cat/K_m of 7.5 × 10⁶ M^?1 × s^?1) and was moderately inhibited by most simple/complex inorganic anions. Potent FbiCA 1 inhibitors were also detected, such as trithiocarbonate, diethyldithiocarbamate, sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid (K_Is in the range of 4–60 μM). Such inhibitors may be used as tools to better understand the role of various β-CA isoforms in photosynthesis.     

2-(1H-Pyrazol-4-yl)acetic acids as CRTh2 antagonists

High throughput screening identified the pyrazole-4-acetic acid substructure as CRTh2 receptor antagonists. Optimisation of the compounds uncovered a tight SAR but also identified some low nanomolar inhibitors.     

A convenient synthesis of lubeluzole and its enantiomer: Evaluation as chemosensitizing agents on human ovarian adenocarcinoma and lung carcinoma cells

Lubeluzole, a neuroprotective anti-ischemic drug, and its enantiomer were prepared following a convenient procedure based on hydrolytic kinetic resolution. The ee values were >99% and 96%, respectively, as assessed by HPLC analysis. The chemosensitizing effects of both enantiomers were evaluated in combination with either doxorubicin (human ovarian adenocarcinoma A2780 cells) or paclitaxel (human lung carcinoma A549 cells) by the MTT assay. At the lowest concentrations used, lubeluzole showed an overall and remarkable tendency to synergize with both anticancer drugs. In ovarian cancer cells a clear prevalence of antagonistic effect was observed for the R-enantiomer. The synergistic effects of lubeluzole for both drugs were observed over a wide concentration window (0.005–5 μM), the lowest limit being at least 40 times lower than human plasma concentrations previously reported as causing serious side effects.     

Progress towards eliminating canine rabies: policies and perspectives from Latin America and the Caribbean

Human rabies transmitted by dogs is considered a neglected disease that can be eliminated in Latin America and the Caribbean (LAC) by 2015. The aim of this paper is to discuss canine rabies policies and projections for LAC regarding current strategies for achieving this target and to critically review the political, economic and geographical factors related to the successful elimination of this deadly disease in the context of the difficulties and challenges of the region. The strong political and technical commitment to control rabies in LAC in the 1980s, started with the regional programme coordinated by the Pan American Health Organization. National and subnational programmes involve a range of strategies including mass canine vaccination with more than 51 million doses of canine vaccine produced annually, pre- and post-exposure prophylaxis, improvements in disease diagnosis and intensive surveillance. Rabies incidence in LAC has dramatically declined over the last few decades, with laboratory confirmed dog rabies cases decreasing from approximately 25 000 in 1980 to less than 300 in 2010. Dog-transmitted human rabies cases also decreased from 350 to less than 10 during the same period. Several countries have been declared free of human cases of dog-transmitted rabies, and from the 35 countries in the Americas, there is now only notification of human rabies transmitted by dogs in seven countries (Bolivia, Peru, Honduras, Haiti, Dominican Republic, Guatemala and some states in north and northeast Brazil). Here, we emphasize the importance of the political commitment in the final progression towards disease elimination. The availability of strategies for rabies control, the experience of most countries in the region and the historical ties of solidarity between countries with the support of the scientific community are evidence to affirm that the elimination of dog-transmitted rabies can be achieved in the short term. The final efforts to confront the remaining obstacles, like achieving and sustaining high vaccination coverage in communities that are most impoverished or in remote locations, are faced by countries that struggle to allocate sufficient financial and human resources for rabies control. Continent-wide cooperation is therefore required in the final efforts to secure the free status of remaining countries in the Americas, which is key to the regional elimination of human rabies transmitted by dogs.     

Human TTRV30M localization within podocytes in a transgenic mouse model of transthyretin related amyloidosis: does the environment play a role?

Transthyretin related amyloidosis is a nosological entity that leads to disability, diminished quality of life, all stages of chronic kidney disease and eventually death. Podocytes are polarized, highly differentiated epithelial cells important for proper nephron function. In the present study we investigated whether deposited TTRVal30Met (TTRV30M) molecules could be localized within podocytes in situ under the effect of different housing conditions (i.e. specific pathogen free [SPF] vs. non-SPF). Murine renal glomeruli from human TTRV30M (hTTRV30M) transgenic mice were examined via direct and indirect immunofluorescence techniques for the presence of hTTRV30M, murine serum amyloid P, activated caspase-3 and NPHS1. Association strength and amount of colocalization for NPHS1?ChTTRV30M, NPHS1-activated caspase-3, hTTRV30M-murine serum amyloid P were estimated. Localization of hTTRV30M in podocytes was demonstrated by immuno-electron microscopy. Renal hTTRV30M gene and NPHS1 gene expression levels were estimated. Non-SPF transgenic mice showed increased glomerular hTTRV30M deposition compared to their SPF counterparts. Furthermore increased podocytic localization of hTTRV30M was noticed in non-SPF mice. Glomerular caspase-3 activation was increased only in the non SPF housing conditions. Podocytic caspase-3 activation was increased in SPF and in non-SPF transgenic mice when compared to non transgenic controls. Environmental conditions influence glomerular deposition and podocytic localization of hTTRV30M. In this context increased caspase-3 activation occurred.     

Differences in Al tolerance between Plantago algarbiensis and P. almogravensis reflect their ability to respond to oxidative stress

We evaluated the impact of low pH and aluminum (Al) on the leaves and roots of Plantago almogravensis Franco and Plantago algarbiensis Samp., focusing on energy partitioning in photosystem II, H₂O₂ levels, lipid peroxidation, electrolyte leakage (EL), protein oxidation, total soluble protein content and antioxidant enzyme activities. In both species, Al triggered more changes in oxidative metabolism than low pH alone, particularly in the roots. We found that Al increased the levels of H₂O₂ in P. algarbiensis roots, but reduced the levels of H₂O₂ in P. almogravensis leaves and roots. Neither low pH nor Al affected the spatial heterogeneity of chlorophyll fluorescence, the maximum photochemical efficiency of PSII (F_v/F_m), the actual quantum efficiency of PSII (?_PSII) or the quantum yields of regulated (?_NPQ) and nonregulated (?_NO) energy dissipation, and there was no significant change in total soluble protein content and EL. In P. algarbiensis, Al increased the carbonyl content and the activities of superoxide dismutase (SOD) and catalase (CAT) in the roots, and also CAT, ascorbate peroxidase and guaiacol peroxidase activities in the leaves. In P. almogravensis, Al reduced the level of malondialdehyde in the roots as well as SOD activity in the leaves and roots. We found that P. almogravensis plantlets could manage the oxidative stress caused by low pH and Al, whereas the P. algarbiensis antioxidant system was unable to suppress Al toxicity completely, leading to the accumulation of H₂O₂ and consequential protein oxidation in the roots.     

Metabolic fingerprinting reveals differences between northern and southern strains of the cryptic diatom Chaetoceros socialis

Morphology and molecular phylogeny constitute the structural elements of diatom taxonomy. These approaches do not, however, give information on the functioning of taxa. Additional methods to serve a more integrated and wide-ranging taxonomy have therefore been called for. Metabolic fingerprinting is one approach used within the field of metabolomics, often applied in classification of samples. Here we apply metabolic fingerprinting in a taxonomic study of a cryptic diatom species. Strains of the cosmopolitan diatom Chaetoceros socialis from two geographical areas; the north-east Atlantic and Arctic and the Gulf of Naples, were cultivated at three different temperatures; 2.5, 8 and 13°C. The strains from the two different geographical areas exhibited different growth rates as well as different photosynthetic efficiencies. Algal extracts, collected at the end of the growth experiments, were analysed by Ultra-Performance Liquid Chromatography High Resolution Mass Spectrometry. The two groups of strains were separated by principal component analysis of their metabolic fingerprints. Analysis of the data revealed both qualitative and quantitative differences in metabolite markers. These phenotypic differences reinforce differences also found for morphology, phylogenetic markers and growth rates, and point at different adaptive characteristics in organisms living under different temperature regimes.