Ecosystem Perspective of Groundwater Arsenic Contamination in India and Relevance in Policy

Millions of people living in India are at risk by consuming arsenic contaminated groundwater. Several technological solutions have failed to address the problem due to segmental approaches, resulting in human suffering for a period of three decades. The article is based on an analysis of arsenic-related health problems from an ecosystem perspective through a primary survey conducted in five arsenic affected villages in the state of West Bengal and review of existing research and policy documents. Although modern agricultural practices and drinking water policies have resulted in arsenic contamination of groundwater, current mitigation policy is essentially confined to biomedical approaches, which includes potable water supply and medical care. The study also shows that existing disparity, difficulty in coping, inaccessibility to health service and potable water supply and lack of participation in decision making have resulted in more suffering among the poor. On the other hand, spreading of arsenic contamination in the ecosystem remains unabated. Foods grown in the affected area have emerged as additional sources of exposure to humans. There is lack of evidence of any perceivable benefits due to sustainable agriculture, as present nature of agriculture practice is essentially driven by crop yield only. Further research is needed to generate credible evidence of alternative agriculture paradigms that may eventually reduce body burden of arsenic through reduced dependency on groundwater.     

Investigation of magnetic field effect on trypsin ativity

Summary Influence of a homogeneous magnetic field on catalytic rate is proposed as a tool for the investigation of enzyme association. Investigations were initiated with studies of the effect of a 1.4 T homogeneous magnetic field on trypsin activity at 36.5° C and pH 3.3, 5.3, and 7.2, respectively. Periods of exposure were applied up to 2–7 h. No detectable change of activity was observed in any of the exposed systems when they were compared with the identical but unexposed ones.     

Development and characterization of 21 polymorphic microsatellite loci in the aphidophagous gall midge, <Emphasis Type="Italic">Aphidoletes aphidimyza</Emphasis> (Diptera: Cecidomyiidae)

We have developed and characterized 21 microsatellite markers in the aphidophagous gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). All 21 loci tested were polymorphic: the number of alleles ranged from 2 to 17. Allelic richness and observed heterozygosities were higher in females than in males. Several loci had no heterozygosity in males, suggesting that the loci were located on sex chromosomes or E-chromosomes, common to cecidomyiids. The high polymorphism detected in this study suggests the markers will be of value in analyzing genetic structure of field populations.     

Human mitochondrial disease-like symptoms caused by a reduced tRNA aminoacylation activity in flies

The translation of genes encoded in the mitochondrial genome requires specific machinery that functions in the organelle. Among the many mutations linked to human disease that affect mitochondrial translation, several are localized to nuclear genes coding for mitochondrial aminoacyl-transfer RNA synthetases. The molecular significance of these mutations is poorly understood, but it is expected to be similar to that of the mutations affecting mitochondrial transfer RNAs. To better understand the molecular features of diseases caused by these mutations, and to improve their diagnosis and therapeutics, we have constructed a Drosophila melanogaster model disrupting the mitochondrial seryl-tRNA synthetase by RNA interference. At the molecular level, the knockdown generates a reduction in transfer RNA serylation, which correlates with the severity of the phenotype observed. The silencing compromises viability, longevity, motility and tissue development. At the cellular level, the knockdown alters mitochondrial morphology, biogenesis and function, and induces lactic acidosis and reactive oxygen species accumulation. We report that administration of antioxidant compounds has a palliative effect of some of these phenotypes. In conclusion, the fly model generated in this work reproduces typical characteristics of pathologies caused by mutations in the mitochondrial aminoacylation system, and can be useful to assess therapeutic approaches.     

A nondestructive method for the measurement of radioactive 14CO2 in blood

A method for estimation of 14CO2 present in blood and tissular samples is described. It is basically based on the introduction of large amounts of a gas mixture (95% O2, 5% CO2) in the samples which serves to remove the CO2 label by gas dilution. The gas phase is later captured in scintillation vials containing an organic-soluble base that retains the carbon label. The results obtained by means of this methodology show much better recoveries for blood samples than those obtained when the classic acid-diffusion method is used. In addition, it is a very fast procedure which does not alter the pH or protein integrity of the biological sample.     

A Chemical Proteomics Approach for the Search of Pharmacological Targets of the Antimalarial Clinical Candidate Albitiazolium in Plasmodium falciparum Using Photocrosslinking and Click Chemistry

Plasmodium falciparum is responsible for severe malaria which is one of the most prevalent and deadly infectious diseases in the world. The antimalarial therapeutic arsenal is hampered by the onset of resistance to all known pharmacological classes of compounds, so new drugs with novel mechanisms of action are critically needed. Albitiazolium is a clinical antimalarial candidate from a series of choline analogs designed to inhibit plasmodial phospholipid metabolism. Here we developed an original chemical proteomic approach to identify parasite proteins targeted by albitiazolium during their native interaction in living parasites. We designed a bifunctional albitiazolium-derived compound (photoactivable and clickable) to covalently crosslink drug–interacting parasite proteins in situ followed by their isolation via click chemistry reactions. Mass spectrometry analysis of drug–interacting proteins and subsequent clustering on gene ontology terms revealed parasite proteins involved in lipid metabolic activities and, interestingly, also in lipid binding, transport, and vesicular transport functions. In accordance with this, the albitiazolium-derivative was localized in the endoplasmic reticulum and trans-Golgi network of P. falciparum. Importantly, during competitive assays with albitiazolium, the binding of choline/ethanolamine phosphotransferase (the enzyme involved in the last step of phosphatidylcholine synthesis) was substantially displaced, thus confirming the efficiency of this strategy for searching albitiazolium targets.