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1.
Indian J Exp Biol ; 2013 Sept; 51(9): 758-763
Article Dans Anglais | IMSEAR | ID: sea-149380

Résumé

The cadaverine (Cad), an organic diamine was examined for its response on growth in salinity and metal stressed B. juncea cv RH-30 vis-à-vis compared the response of ammonium nitrate. The Cad (1 mM) application ameliorated the effect caused by salinity and metal stress on seed germination and plant growth. The plant growth recovery (dry biomass accumulation) was dependent on stress and diamine type. The higher growth recovery potential of Cad under both stresses was due to elevation in photosynthetic pigments, nitrate reductase activity and organic nitrogen as well as soluble protein, It is inferred that growth in stressed seedlings was mediated by Cad through lowering endogenous Cd/Pb and Na+/K+ level in leaf and shoot tissues.


Sujets)
Cadavérine/pharmacologie , Cadmium/métabolisme , Plomb/métabolisme , Moutarde (plante)/effets des médicaments et des substances chimiques , Moutarde (plante)/croissance et développement , Moutarde (plante)/physiologie , Nitrate reductase/métabolisme , Azote/métabolisme , Photosynthèse , Pigments biologiques/métabolisme , Stress physiologique
2.
Indian J Exp Biol ; 2013 Jul; 51(7): 543-547
Article Dans Anglais | IMSEAR | ID: sea-147625

Résumé

A total of 75 isolates belonging to five different species of Trichoderma viz., T. asperellum, T. harzianum, T. longibrachiatum, T. pseudokoningii and T. virens were screened for the production of silver nanoparticles. Although all the isolates produced nanoparticles, T. virens VN-11 could produce maximum nanoparticles as evident from the UV-Vis study. The highest Plasmon band was observed at 420 nm at every 24 h that attained maximum intensity at 120 h (0.543). The high resolution transmission electron microscopy (HRTEM) further provided the morphology of the nanoparticles. These nanoparticles were found single or aggregated with round and uniform in shape and 8-60 nm in size. The nitrate reductase activity of VN-11 was found to be 150 nmol/h/mL which confirmed the production of silver nanoparticles through reduction of Ag+ to Ag0.


Sujets)
Nanoparticules métalliques/composition chimique , Nanoparticules métalliques/ultrastructure , Microscopie électronique à transmission , Nanotechnologie , Nitrate reductase/métabolisme , Taille de particule , Argent/composition chimique , Trichoderma/classification , Trichoderma/métabolisme
3.
Mem. Inst. Oswaldo Cruz ; 107(5): 578-581, Aug. 2012. ilus, tab
Article Dans Anglais | LILACS | ID: lil-643741

Résumé

The microplate nitrate reductase assay (MNRA) and the rezasurin microtitre assay (REMA) were used for the susceptibility testing of 73 clinical isolates and the results were compared with those that were obtained using the Bactec 460 TB and Bactec MGIT 960 systems. The REMA and the MNRA were performed in 96-well plates. For the REMA, the concentrations of isoniazid (INH) and rifampicin (RIF) ranged from 1.0-0.01 µg/mL and 2.0-0.03 µg/mL, respectively. For the MNRA, the INH concentration was between 1.0-0.03 µg/mL and the RIF concentration was between 2.0-0.06 µg/mL. For the MNRA, the sensitivity, specificity, positive predictive value, negative predictive value and INH/RIF agreement were 100/95.6, 97.6/100, 96.8/100, 100/98 and 98.6/98.6, respectively, and for the REMA, they were 100/91.3, 90.4/100, 88.5/100, 100/96.1 and 94.5/97.2, respectively. Our data suggest that these two rapid, low-cost methods may be inexpensive, alternative assays for the rapid detection of multidrug resistant tuberculosis in low-income countries.


Sujets)
Humains , Antituberculeux/pharmacologie , Multirésistance bactérienne aux médicaments/effets des médicaments et des substances chimiques , Isoniazide/pharmacologie , Tests de sensibilité microbienne/méthodes , Mycobacterium tuberculosis/effets des médicaments et des substances chimiques , Rifampicine/pharmacologie , Mycobacterium tuberculosis/isolement et purification , Nitrate reductase/métabolisme , Oxazines/métabolisme , Valeur prédictive des tests , Trousses de réactifs pour diagnostic , Sensibilité et spécificité , Tuberculose multirésistante/microbiologie , Xanthènes/métabolisme
4.
J Environ Biol ; 2008 Mar; 29(2): 197-200
Article Dans Anglais | IMSEAR | ID: sea-113600

Résumé

Ceratophyllum demersum (homwort) was subjected to toxic concentrations of Al (3 and 9 mg l(-1)), Zn (3 and 9 mg l(-1)) and Cu (2.5 and 7 mg l(-1)) in culture solutions for 15 days. The higher dose of Al enhanced the chlorophyll content significantly (p<0.05) in the first 6 days of treatment while other treatments caused marked reductions. Nitrate reductase activity (NRA) was significantly reduced (p<0.05) byAl, Cu and Zn toxicity and ceased completely in plants treated with Cu by the 6th day of treatment. Dry biomass and relative growth rate were reduced significantly (p<0.05) by metal treatment. Tolerance index of the plant was low for Cu (21.62 and 13.43% at low and high doses, respectively) and moderate for Zn (63.74 and 54.85%) and Al (72.83 and 68.79%). Accumulation ofAl, Zn and Cu was threefold at higher doses compared with the lower doses but the bioconcentration factors (BCF) were very low indicating that this plant is not a hyper accumulator of these metals.


Sujets)
Aluminium/pharmacocinétique , Magnoliopsida/effets des médicaments et des substances chimiques , Chlorophylle/métabolisme , Cuivre/pharmacocinétique , Relation dose-effet des médicaments , Tolérance aux médicaments , Exposition environnementale , Nitrate reductase/métabolisme , Facteurs temps , Polluants chimiques de l'eau/pharmacocinétique , Zinc/pharmacocinétique
5.
J Environ Biol ; 2007 Apr; 28(2): 303-6
Article Dans Anglais | IMSEAR | ID: sea-113277

Résumé

The effect of mercury (Hg) on the biochemical parameters of Lycopersicon esculentum Mill leaf was studied. Application of mercuric chloride in varying concentrations (0.5, 1.0, 1.5 and 2.0 mM HgCl2 kg(-1) sand) caused significant reduction that went up to 89% and 72% chlorophyll a and chlorophyll b contents respectively (at flowering stage), 69% in carotenoid content, 64% in total soluble protein content and 91% in nitrate reductase activity (all at post-flowering stage). The amounts of nitrate and proline increased maximally (151% and 143% respectively) at the flowering stage, whereas total soluble sugar enhanced by 57% at the post-flowering stage. Changes observed in most of the parameters, were concentration dependent. Such studies seem to be able to discover suitable bioindicators of heavy metal pollution.


Sujets)
Métabolisme glucidique/effets des médicaments et des substances chimiques , Caroténoïdes/métabolisme , Chlorophylle/métabolisme , Solanum lycopersicum/effets des médicaments et des substances chimiques , Mercure/toxicité , Nitrate reductase/métabolisme , Nitrates/métabolisme , Feuilles de plante/effets des médicaments et des substances chimiques , Protéines végétales/métabolisme , Proline/métabolisme , Polluants du sol/toxicité
6.
J Environ Biol ; 2007 Jan; 28(1): 127-32
Article Dans Anglais | IMSEAR | ID: sea-113598

Résumé

In the present study species like Mangifera indica, Linn., Cassia fistula, Linn., and Eucalyptus hybrid were exposed to different air pollution load for short duration (active biomonitoring). Variation in biochemical parameters like chlorophyll, protein, soluble sugar free amino acid, ascorbic acid, nitrate reductase, superoxide dismutase and peroxidase in the leaves were found to be pollution load dependent. These variations can be used as indicators of air pollution for early diagnosis of stress or as a marker for physiological damage to trees prior to the onset of visible injury symptoms. Just by analyzing these biochemical indicators air quality can also be assessed.


Sujets)
Polluants atmosphériques/analyse , Pollution de l'air/effets indésirables , Acides aminés/métabolisme , Magnoliopsida/effets des médicaments et des substances chimiques , Acide ascorbique/métabolisme , Métabolisme glucidique , Chlorophylle/métabolisme , Surveillance de l'environnement , Inde , Nitrate reductase/métabolisme , Oxydes d'azote/analyse , Matière particulaire/analyse , Myeloperoxidase/métabolisme , Protéines végétales/métabolisme , Dioxyde de soufre/analyse , Superoxide dismutase/métabolisme
7.
J Environ Biol ; 2006 Jan; 27(1): 71-5
Article Dans Anglais | IMSEAR | ID: sea-113618

Résumé

Present study was undertaken as an attempt to study the effect of pollutants on biological responses of Sphagnum growing at Kainchi, Kumaon hills (Uttranchal). Sphagnum plants of almost identical size, collected from the marked sites of Kainchi in different seasons viz., monsoon, winter, summer and again in monsoon, were analysed for chlorophyll, protein, shoot length and nitrate reductase and peroxidase activities. Maximum chlorophyll, protein, shoots length and nitrate reductase activities were observed during the monsoon while minimum in summers. The abundance of Sphagnum and two other bryophytes, Marchantia and Plagiochasma was also higher in monsoon than in other seasons. The study also indicated that Sphagnum has more bioaccumulation and tolerance potential for heavy metals than Marchantia and Plagiochasma.


Sujets)
Chlorophylle/métabolisme , Surveillance de l'environnement , Inde , Métaux lourds/métabolisme , Nitrate reductase/métabolisme , Myeloperoxidase/métabolisme , Protéines végétales/métabolisme , Pousses de plante , Saisons , Sphagnopsida/effets des médicaments et des substances chimiques
8.
Electron. j. biotechnol ; 7(3): 13-14, Dec. 2004. ilus, tab, graf
Article Dans Anglais | LILACS | ID: lil-448770

Résumé

The ubiquity of heavy metals in the biosphere results in the introduction of high amounts of toxic metals into the food chain from various sources. In the present study, one of the strongest nitrogen fixing cyanobacterium of the rice fields, Aulosira fertilissima, was subjected to nickel and chromium stress and the ameliorating effect of immobilization was investigated. Cell immobilization could protect the organism's growth against the toxicity of both heavy metals at LC50 as compared to lethal concentrations. The nitrate reductase activity in free cells treated with the metals was substantially inhibited but immobilized cells treated with 0.1 ppm nickel was not affected by the metal treatment. Cell immobilization also resulted in a significant protection against sub-lethal concentration of chromium but to a lesser degree than it did with sub- lethal levels of nickel. Control immobilized cells also had higher Nitrogenase activity than control free cells. Nickel and chromium addition markedly decreased the enzyme activity in free cells but immobilized cells exposed to sublethal concentrations of both metals could overcome this decrease. Glutamine synthetase showed similar response under immobilized conditions compared to free cells with both metals. The addition of algal filtrate in 3:1 ratio further increased the nitrogenase activity compared with immobilized cells treated with sublethal doses of both metals. Immobilization facilitated higher uptake of nickel as compared to chromium. The observations of the present study clearly demonstrate the protective effect of immobilization on Aulosira fertilissima against Nickel and chromium toxicity. Rice field ecosystem thus possess a bidirectional natural metal ameliorating system where Aulosira mats act as a naturally immobilized system and the decay of Aulosira along with other cyanobacteria act as natural chelators protecting the rice plants from deleterious effects of the heavy metals. Most importantly is...


Sujets)
Cyanobactéries/métabolisme , Chrome/métabolisme , Nickel/métabolisme , Agriculture , Cyanobactéries/enzymologie , Pollution chimique de l'eau/prévention et contrôle , Chrome/toxicité , Glutamate-ammonia ligase/métabolisme , Fixation de l'azote , Nickel/toxicité , Nitrate reductase/métabolisme , Nitrogenase/métabolisme
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