Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Feasibility studies of a constructed wetland to treat contaminated water

Among the vast number of methods that can be applied for the treatment of contaminated water, one of the best methods of treating of abandoned mine water was identified as the subsurface flow constructed wetlands through pytoextraction. Therefore further research was carried out to the applicability of constructed wetland to treat polluted water at abandoned quarry in Ragama (Prison Quarry). The main objective of the study was to measure the removal efficiencies of BOD, COD, NH3, NO3', PO.*3- using Thypha Latifolia (Cattail). The hydraulic retention time was 8 days. The concentration of Nitrate, Orthophosphate and Ammonia was monitored twice a week and BOD and COD were monitored once a week in order to determine their removal rates. While monitoring the removal efficiencies, the mechanisms of N, P and COD removals were identified. The mechanisms are based on the principle of mass conservation. The main nitrogen removal mechanisms identified were plant uptake and denitrification. It is assumed that ammonia and nitrate removal from wetlands by macropytes depended on the biomass of the roots. Average Nitrate and Ammonia removal from the planted cell was 42.9% and 27.8%, respectively, whereas the removal efficiency of Ortho Phosphate was 17.5% in the planted tank. Typha latifolia was identified as a suitable wetland plant which can remove nitrogen compounds in contaminated water

Soil Stabilization Against Water Erosion via Calcite Precipitation by Plant-Derived Urease

Stabilization is often necessary to improve the stiffness, strength and durability of both natural and compacted soils. Soils are typically stabilized via the addition of hydraulic binders, such as cement and lime, which present however relatively high carbon and energy footprints. Alternative stabilization techniques are therefore explored to minimize environmental impact while preserving good material properties. Among these techniques, enzyme induced calcite precipitation (EICP) has gained prominence in recent years. EICP exploits the action of the urease enzyme to catalyze the hydrolysis of urea and to produce carbonate ions, which then react with calcium ions inside the pore water to cause precipitation of calcium carbonate (i.e. calcite). The precipitated mineral bonds particles together, thus improving the hydro-mechanical characteristics of the soil. This paper presents a preliminary investigation on the use of plant-derived urease, instead of pure reagent-grade urease, to minimize environmental and financial costs. The urease enzyme is obtained from a liquid soybeans extract, inside which urea and calcium chloride are dissolved. This stabilizing solution is then mixed with a silty clay to produce stabilized samples, which are subjected to water erosion tests