Determination of Phosphate in Soil Extracts in the Field: A Green Chemistry Enzymatic Method
News Aug 18, 2015
Measurement of ortho-phosphate in soil extracts usually involves sending dried samples of soil to a laboratory for analysis and waiting several weeks for the results. Phosphate determination methods often involve use of strong acids, heavy metals, and organic dyes. To overcome limitations of this approach, we have developed a phosphate determination method which can be carried out in the field to obtain results on the spot.
This new method uses:
• Small volumes.
• An enzymatic reaction.
• Green chemistry.
First, the soil sample is extracted with deionized water and filtered. Next, an aliquot of the soil extract (0.5 mL) is transferred to a disposable cuvette, containing 0.5 mL of reaction mixture [200 mM HEPES, pH 7.6, 20 mM MgCl2, with 80 nmol 2-amino-6-mercapto-7-methylpurine ribonucleoside (MESG) and 1 unit of recombinant purine nucleoside phosphorylase (PNP; EC 126.96.36.199)], mixed, and incubated for 10 min at field temperature. Absorbance of the completed reaction is measured at 360 nm in open-source, portable photometer linked by bluetooth to a smartphone. The phosphate and phosphorus content of the soil is determined by comparison of its absorbance at 360 nm to a previously prepared standard phosphate curve, which is stored in the smartphone app.
Cellular Valve Structure Opens Up Potential Novel TherapiesNews
Biochemists have determined the detailed structure of a volume-regulated chloride channel. This cellular valve is activated in response to swelling to prevent the cell from bursting. The protein also plays an important role in the uptake of chemotherapeutics and the release of neurotransmitters after a stroke. The controlled regulation of its activity thus opens up a promising strategy for novel therapies.READ MORE
Growing Issue of Pesticide Resistance - Action Needed!News
A review has found that large-scale studies are required to test new approaches for slowing pest resistance as herbicide and pesticide resistance is a growing problem.READ MORE