Studies on the Effect of Typha angustata (Reed) on the Removal of Sewage Water Pollutants

Rhizoremediation is the process in which exudates derived from the plant root stimulate the survival and activity of the soil bacteria and fungi, resulting in a more efficient degradation of water soluble pollutants in rhizosphere. The present study was carried out in the zone of naturally growing reed plants (reed zone) and zone not occupied by Typha angustata along the banks of a domestic sewage pool in one of the residential areas of Puducherry. The lower levels of biochemical oxygen demand(BOD) and total dissolved solids (TDS) and lower concentration  of heavy metals such as lead, manganese, zinc and copper and higher level of dissolved oxygen (DO) were  noticed in the Reed (Typha angustata) root zone compared to non reed root zone. Though all the six bacterial species under five types of bacterial populations and eight types of fungal populations were found in both the zones, the numbers of colonies were found to be more in reed zone than non reed root zone. This suggests that the rhizosphere of Typha angustata has a direct influence on the composition and density of soil microbial community. Exudates of Reed plant caused an increase in the metabolic activity of microbes of the rhizosphere and transformed the organic and inorganic pollutants into harmless compounds. It is concluded that Typha root zone with its myriad of microbes served as a bio-bed which has the potential to reduce the BOD and TDS levels of sewage water, decrease the concentration of heavy metals and increase dissolved oxygen in the water body

EBF1-deficient bone marrow stroma elicits persistent changes in HSC potential

Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here, we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFRα+Sca1+ (PαS) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition, chromatin structure and gene expression profiles, including the reduced expression of adhesion-related genes. Functionally, the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs, leading to reduced quiescence and diminished myeloid output. Most notably, HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus, genetic alterations in the BM niche lead to long-term functional changes of HSCs

Coupled-barrier diffusion: the case of oxygen in silicon

Oxygen migration in silicon corresponds to an apparently simple jump between neighboring bridge sites. Yet, extensive theoretical calculations have so far produced conflicting results and have failed to provide a satisfactory account of the observed $2.5$ eV activation energy. We report a comprehensive set of first-principles calculations that demonstrate that the seemingly simple oxygen jump is actually a complex process involving coupled barriers and can be properly described quantitatively in terms of an energy hypersurface with a ``saddle ridge'' and an activation energy of $\sim 2.5$ eV. Earlier calculations correspond to different points or lines on this hypersurface.Comment: 4 Figures available upon request. Accepted for publication in Phys. Rev. Let

On the large sunfish landed near Mandapam

A sunfish, Ranzania laevis (Pennant) measuring 660 mm total length was caught on 5.3.1998 in shoreseine near Mandapam in Palk Bay. In fresh condition its colour was bluish with dark above and pale white below with small hexagonal plates and smooth skin. Six streaks of lighter colour bordered with dark descended from snout to gill slits and curved downwards to the ventral profile. The posterior three streaks were branched with dark spots. The lips were produced forward beyond the teeth closing as a vertical slit