Inter-laboratory validation of an ISO test method for measuring enzyme activities in soil samples using colorimetric substrates.

The evaluation of soil quality requires the use of robust methods to assess biologically based indicators. Among them, enzyme activities are used for several decades, but there is a clear need to update their measurement methods for routine use, in combining feasibility, accuracy, and reliability. To this end, the platform Biochem-Env optimized a miniaturized method to measure enzyme activities in soils using colorimetric substrates in micro-well plates.

A dansyl-derivatized phytic acid analogue as a fluorescent substrate for phytases: experimental and computational approach.

A new myo-inositol pentakisphosphate was synthesized, which featured a dansyl group at position C-5. The fluorescent tag was removed from the inositol by a 6-atom spacer to prevent detrimental steric interactions in the catalytic site of phytases. The PEG linker was used in order to enhance hydrophilicity and biocompatibility of the new artificial substrate.

Expression of a phosphate-starvation inducible fructose-1,6-bisphosphatase gene in common bean nodules correlates with phosphorus use efficiency.

While increased P-hydrolysing acid phosphatases (APase) activity in bean nodules is well documented under phosphorus (P) limitation, gene expression and subcellular localization patterns within the N-fixing nodule tissues are poorly understood. The aim of this research was to track the enzyme activity along with the intra-nodular localization of fructose-1,6-bisphosphatase (FBPase), and its contribution to P use efficiency (PUE) under symbiotic nitrogen fixation (SNF) in Phaseolus vulgaris. The FBPase transcript were localized in situ using RT-PCR and the protein activity was measured in nodules of two contrasting recombinant inbred lines (RILs) of P.

Localization of phytase transcripts in germinating seeds of the common bean (Phaseolus vulgaris L.).

The work provides the first-time evidence of tissue-specific expression of a phytase gene in the germinating seeds of Phaseolus vulgaris. Phytase enzyme plays a major role in germinating seeds. It is also active during N2 fixation within nodules of legumes.

A phytase gene is overexpressed in root nodules cortex of Phaseolus vulgaris-rhizobia symbiosis under phosphorus deficiency.

Phosphorus is an essential nutrient for rhizobial symbioses to convert N2 into NH4 usable for N nutrition in legumes and N cycle in ecosystems. This N2 fixation process occurs in nodules with a high energy cost. Phytate is the major storage form of P and accounts for more than 50 % of the total P in seeds of cereals and legumes.

Differential expression of trehalose 6-P phosphatase and ascorbate peroxidase transcripts in nodule cortex of Phaseolus vulgaris and regulation of nodule O2 permeability.

Although the role of phosphatases and antioxidant enzymes have been documented in phosphorus (P) deficiency tolerance, gene expression differences in the nodules of nitrogen fixing legumes should also affect tolerance to this soil constraint. In this study, root nodules were induced by Rhizobium tropici CIAT899 in two Phaseolus vulgaris recombinant inbred lines (RIL); RIL115 (low P-tolerant) and RIL147 (low P-sensitive) under hydroaeroponic culture with sufficient versus deficient P supply. Trehalose 6-P phosphatase and ascorbate peroxidase transcripts were localized within nodules in which O2 permeability was measured.