Isolation and characterization of a lead (Pb) tolerant <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> strain HF5 for decolorization of reactive red-120 and other azo dyes

Presence of heavy metals including lead (Pb) in the textile effluents is a crucial factor affecting the growth and potential of the dye decolorizing bacterial strains. This work was planned to isolate and characterize a bacterial strain exhibiting the potential to decolorize a range of azo dyes as well as the resistance to Pb. In this study, several Pb tolerant bacteria were isolated from effluents of textile industry. These bacterial isolates were screened for their potential of decolorizing the reactive red-120 (RR120) azo dye with presence of Pb (50 mg L^?1). The most efficient isolate was further characterized for its potential to resist Pb and decolorize different azo dyes under varying cultural and incubation conditions. Out of the total 82 tested bacterial isolates, 30 bacteria were found to have varying potentials to resist the presence of lead (Pb) and carry out decolorization of an azo dye reactive red-120 (RR120) in the medium amended with Pb (50 mg L^?1). The most efficient selected bacterium, Pseudomonas aeruginosa strain HF5, was found to show a good potential not only to grow in the presence of considerable concentration of Pb but also to decolorize RR120 and other azo dyes in the media amended with Pb. The strain HF5 completely (>?90%) decolorized RR120 in mineral salt medium amended with 100 mg L^?1 of Pb and 20 g L^?1 NaCl. This strain also considerably (>?50%) decolorized RR120 up to the presence of 2000 mg L^?1 of Pb and 50 g L^?1 of NaCl but with reduced rate. The optimal decolorization of RR120 by HF5 was achieved when the pH of the Pb amended (100 mg L^?1) mineral salt media was adjusted at 7.5 and 8.5. Interestingly, this strain also showed the tolerance to a range of metal ions with varying MIC values. The Pseudomonas aeruginosa strain HF5 harboring the unique potentials to grow and decolorize the azo dyes in the presence of Pb is envisaged as a potential bioresource for devising the remediation strategies for treatment of colored textile wastewaters loaded with Pb and other heavy metal ions.     

Dosimetric effect of limited aperture multileaf collimator on VMAT plan quality: A study of prostate and head-and-neck cancers

Aim

The aim of study was to evaluate the dosimetric effect of collimator-rotation on VMAT plan quality, when using limited aperture multileaf collimator of Elekta Beam Modulator? providing a maximum aperture of 21 cm × 16 cm.

Comparison of phosphorus deficiency indices during a spring phytoplankton bloom in a eutrophic reservoir

1. Phosphorus limitation was studied along the eutrophic, canyon-type ?ímov reservoir (Czech Republic) during a spring phytoplankton bloom. Concentration of soluble reactive phosphorus (SRP), C:P molar ratio in seston, extracellular alkaline phosphatase activity (APA), and P limitation (bioassay) were used as indices for phosphorus deficiency in the phytoplankton. 2. SRP, C:P, APA, and P limitation indicated a moderate P deficiency in the downstream, but not upper, part of the reservoir. 3. Significant correlations between these parameters were found in the downstream part. Chlorophyll a concentration correlated with APA and P limitation in the upper part. 4. APA was significantly enhanced in the phosphorus-deficient phytoplankton. However, APA was apparently not related to total biomass or species composition of the phytoplankton. 5. Generally, APA was closely correlated with pH in the reservoir. However, extracellular alkaline phosphatases, with a pH optimum above 9.0, were induced and active only during the phytoplankton bloom, whereas low background activity of extracellular phosphatases was found at low chlorophyll a concentrations (winter, clear-water phase).     

The Function of Urease in Citrullus Seeds

Urease is present in considerable quantity in the cotyledonsof Citrullus, though elsewhere in the plant it is present onlyin traces or is absent; urease activity in the cotyledons changesduring growth, showing an initial rise followed by an abruptdrop almost to zero. These changes, under a wide variety ofconditions, are not correlated with those in the major nitrogenfractions; they are, however, closely correlated with cell extensionand the associated changes in water content and respiration.A connexion with chlorophyll formation is possible but unlikely.It is suggested that the changes in cotyledonary urease constitutemerely one aspect of the ‘protoplasmic differentiation’that takes place as a cell matures.     

Characterization ofAzospirillum and related diazotrophs associated with roots of plants growing in saline soils

Diazotrophs, especially of genusAzospirillum were readily isolated from roots of many plants using semi-solid nitrogen free malate medium (NFM). These isolates formed fine, white sub-surface pellicle in nitrogen-free malate medium within 24h, which gradually moved to the surface, and exhibited high acetylene reduction rates. Using selected cultural and biochemical tests, most of the isolates were identified asAzospirillum brasilense. Four isolates from Kallar grass root surface and one isolate fromAtriplex root interior formed phenotypically a homogenous group. It shared many characteristics with the species of genusAzospirillum except shape. All the biochemical tests performed, categorized them withA. brasilense. However, the shape and the protein profile on SDS polyacrylamide gel electrophoretograms suggested that the group of these five isolates is clearly distinct and differs widely from all the type strains, belonging to various genera.

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Résumé It est apparu facile d'isoler des diazotrophes, principalement du genreAzospirllium à partir de racines de nombreuses plantes et utilisant un milieu malate semisolide exempt d'azote (NFM). Ces isolats forment une pellicule fine et blanche sous la surface dans le milieu malate exempt d'azote, endéans les24h. Ces pellicules ae déplacent progressivement vers la surface et exhibent des vitesses élevées de production d'acétylène. L'emploi de tests de culture sélective ou biochimique, a permis d'identifier la plupart des isolats commeAzospirillum brasilense. Quatre isolats à partir de la surface des racines d'herbe Kallar et un isolat à partir de l'intérieur d'une racine d'Atriplex forment an groupe homogène sur le plan phénotypique. Celui-ci partage de nombreuses caractéristiques avec les espèces du genreAzospirillum excepté la forme. Tous les tests biochimiques exécutés les rangent avecA. brasilense. Toutefois, leur forme ainsi que le profil protéique sur un électrophérogramme sur gel de polyacrylamide-SDS suggèrent que le groupe de cinq isolats est nettement distinct et diffère largement de toutes les souches types, appartenant à de nombreux genres.

     

Characterization of new microsatellite loci from Vitis vinifera and their conservation in some Vitis species and hybrids

We present here characterization data for seven new microsatellite markers designed from new microsatellite loci isolated from a microsatellite‐enriched DNA library from Vitis vinifera. The observed heterozygosity varied from 0.73 up to 0.93 and the number of alleles per locus ranged from 12 to 26. This high polymorphism makes these new markers interesting for use in genotyping studies and completing the set of microsatellite markers already available for V. vinifera. Additionally these seven new markers appear to be conserved in four other Vitis species and 15 Vitis hybrids used as rootstocks for V. vinifera cultivation.