Evaluation of Ageratum conyzoides in field scale constructed wetlands (CWs) for domestic wastewater treatment

Ageratum conyzoides were evaluated in field scale subsurface flow constructed wetlands (CWs) to quantify its nitrogen (N) and phosphorus (P) uptake and compare with wetland plants (Pistia stratiotes, Typha latifolia and Canna indica). The two-field scale subsurface flow CWs, located in the International Crops Research Institute for Semi-Arid Tropics, received wastewater from an urban colony. The CW1 and CW2 had the same dimensions (length:10 m, width:3 m, total depth:1.5 m and sand and gravel:1 m), similar flow rates (3 m³/d), hydraulic loading rates (HLRs-10 cm/d) and hydraulic retention time (HRT-5 days) from July 2014-August 2015. The vegetation in both CWs consisted of Pistia stratiotes, Typha latifolia, Canna indica, and Ageratum conyzoides, respectively. The CW1 (% reduction with respect to concentrations) reduced total suspended solids (TSS) (68%), NH₄-N (26%), NO₃-N (30%), soluble reactive P (SRP) (20%), chemical oxygen demand (COD) (45%) and fecal coliforms (71%), while the CW2 (%-reduction with respect to concentrations) reduced TSS (63%), NH₄-N (32%), NO₃-N (26%), SRP (35%), COD (39%) and fecal coliforms (70%). Ageratum conyzoides can be used in combination with Pistia stratiotes, Typha latifolia and Canna indica to enhance removal of excessive N, P and fecal coliforms from domestic wastewater.

Arginine dependence of tumor cells: targeting a chink in cancer's armor

Arginine, one among the 20 most common natural amino acids, has a pivotal role in cellular physiology as it is being involved in numerous cellular metabolic and signaling pathways. Dependence on arginine is diverse for both tumor and normal cells. Because of decreased expression of argininosuccinate synthetase and/or ornithine transcarbamoylase, several types of tumor are auxotrophic for arginine. Deprivation of arginine exploits a significant vulnerability of these tumor cells and leads to their rapid demise. Hence, enzyme-mediated arginine depletion is a potential strategy for the selective destruction of tumor cells. Arginase, arginine deiminase and arginine decarboxylase are potential enzymes that may be used for arginine deprivation therapy. These arginine catabolizing enzymes not only reduce tumor growth but also make them susceptible to concomitantly administered anti-cancer therapeutics. Most of these enzymes are currently under clinical investigations and if successful will potentially be advanced as anti-cancer modalities.

Growth of salmonellas in different enrichment media

The usefulness of selenite-F (S-F), tetrathionate (MKT) and Rappaport-10 (R-10) broths as enrichment media to support growth of salmonellas either alone or in the presence of other competing organisms was studied. Their ability to support the growth of stressed salmonellas from water was also investigated. It was observed that R-10 was more inhibitory to competing organisms than MKT and S-F. It strongly inhibited the growth of Pseudomonas aeruginosa, Citrobacter freundii and Proteus vulgaris though not of Escherichia coli and Enterobacter aerogenes. It was more toxic, however, to small numbers of salmonellas than MKT and S-F. Tetrathionate was strongly inhibitory for E. coli and Ent. aerogenes but much less so for Proteus and Pseudomonas species. Selenite-F was much less inhibitory than MKT to Ps. aeruginosa and it did not inhibit growth of E. coli and Ent. aerogenes as much as MKT. Salmonellas were inhibited by all three enrichment media and none of them is ideally suited for direct use. Of the three media, R-10 was much more inhibitory to stressed organisms than S-F or MKT.