No abstract

Extracellular alkaline protease from the alkalophilic bacterium Alcaligenes faecalis was purified by a combination of ion-exchange and size-exclusion chromatographic methods, and its properties were examined. The purified enzyme had a specific activity of 563.8 micromol of tyrosine/min per mg of protein and gave a single band on native PAGE and SDS/PAGE with a molecular mass of 67 kDa. Gelatin zymogram also revealed one clear zone of proteolytic activity which corresponded to the band obtained with native PAGE and SDS/PAGE. The enzyme had an optimal pH of 9.0 and exhibited its highest activity at 55 degrees C. The enzyme activity was inhibited by PMSF, suggesting the presence of serine residues at the active site. The enzyme had a K(m) of 1.66 mg/ml and a V(max) of 526 units/min per mg of protein with casein as the substrate.

No abstract

No abstract

Salinity is a major abiotic stress that affects rice cultivation. Osmotic stress caused by salinity activates tolerance mechanisms in rice. The Abscisic Acid Responsive Element Binding Protein (ABRE-BP), transcribes for a bZIP family transcription factor that binds to the cis-regulatory element Abscisic Acid Responsive Element (ABRE) at the promoter of downstream salinity responsive genes and regulates their expression. Hence, the study was focused on analyzing the nucleotide diversity of a region in ABRE-BP promoter. Analysis of the ABRE-BP sequences of 47 Sri Lankan rice varieties and two reference varieties retrieved from a public database revealed many insertions and deletions (INDELs) and single nucleotide polymorphisms (SNPs) in the promoter. Eleven, abiotic stress related cis-elements were identified, but none of the INDELs spanned over them. However, SNPs either deleted existing cis-elements or created new cis-elements. The salinity stress responsive elements, MYBCORE and GT1GMSCAM4 were detected in few varieties, and were not associated with salinity tolerance based on current available salinity ratings. The presence of SNPs in cis-elements clustered them to nine groups at 68% similarity. The DNA polymorphisms on stress responsive cis-acting elements did not show a strong association with the known salinity ratings of many varieties. Nevertheless, the presence of INDELs affects the relative distance between elements, and thus may alter the expression of the ABRE-BP that regulates downstream stress responsive genes.