Résumé
Pulp and paper industry is one of the major sources of man-made generation of organochlorine compounds. During biological treatment of wastewater, part of organochlorine compounds is discharged with treated effluent and part is retained on biomass and disposed of as waste activated sludge. Due to presence of these compounds, the disposal of biosludge from pulp and paper industry has become an issue. The estimation of adsorbable organic halogen (AOX) compounds after drying and grinding resulted in 49% lower concentration of AOX due to stripping of purgeable compounds. These purgeable compounds are not released at 60oC in aqueous medium during estimation of purgeable organic halogen (POX) compounds. Dispersion of sludge by sonication overcomes the loss of POX compounds and results in higher concentration of AOX compounds. The drying of biosludge samples at 45, 100 oC and in presence of sun light resulted in 20.1, 49.0 and 29.6% removal of purgeable AOX compounds, respectively. The lab scale sorption study using dichloromethane (as volatile organochlorine compound) reveal that biosludge from pulp and paper industry is a good adsorbent of volatile organochlorine compounds and results in poor release of these compounds during estimation of POX compounds.
Résumé
Sixty-seven isolates of Phytophthora infestans collected from Himalayan hill regions and subtropical planes of India were characterized by RAPD markers to assess diversity and differentiation based on location of origin. Ten random decamer primers generated 161 polymorphic fragments. Association of P. infestans isolates on the dendrogram and PCO plot revealed two clear grouping based on geographical location of origin-hill isolates and plane isolates. Quantification of diversity by Shannon index of diversity analysis demonstrated that most of the diversity was present with a particular population (hill or plane) of P. infestans isolates, with 85% variation being within and 15% being between hill and plane isolates. Subtropical plane isolates of P. infestans exhibited higher variability compared to hill isolates and they were more dispersed on the PCO plot. No clear differentiation of isolates based on mating type was reflected on the dendrogram and PCO plot.
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ADN/métabolisme , Amorces ADN/composition chimique , Marqueurs génétiques , Variation génétique , Modèles statistiques , Phylogenèse , Phytophthora/génétique , Réaction de polymérisation en chaîne , Polymorphisme génétique , Technique RAPDRésumé
RAPD based fingerprinting of 21 serovars of Bacillus thuringiensis (Bt) representing different serotypes was performed using 19 random decamer primers. A total of 172 polymorphic fragments, ranging in size from 161-2789 bp, were amplified from 13 of the 19 primers. Pairwise genetic similarity analysis revealed very low similarity values, ranging from 3-68%, among the serovars of Bt, indicating high genetic divergence. Nineteen serovars of Bt fell in two major clusters and remaining two formed solitary clusters in the dendogram. Clustering of Bt strains established genetic relatedness between serovars and serotypes. It has been suggested that RAPD analysis can be used for genotypic characterization of Bt to complement flagellar serotyping.