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1

Role of biosorbent ficus religiosa leaf powder (frlp) in chemical speciation of chromium: a green method for separation

100%

Goyal P. , Srivastava S.

Archives of Environmental Protection

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2008

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tom Vol. 34, no. 4

35-45

EN

The present study explores the unexploitcd sorption property of the unmodified Ficus religiosa leaf powder (FRLP) for decontamination and a possible method of separation of environmentally important two oxidation states of chromium (Cr(lII) and Cr(VI)) from aqueous media. Sorption studies using standard practices were carried out in batch experiments as functions of biomass dosage, metal concentration, contact time, particle size and pH. Sorption studies result into the standardization of optimum conditions for the removal of Cr(III) 82.47% and Cr(VI) 88.23% as follows: biomass dosage (4.0 g), initial metal concentration in the aqueous system (Cr(III) 25 mg-dm-1, Cr(VI) 50 mg-dm'), particle size (105 urn) at pH (Cr(lll) - 6.5 and Cr(VI) -2.5). The adsorption data were fitted in Freundlich and Langmuir isotherms. Studies of academic interest like kinetics studies revealed that adsorption equilibrium in each case followed first order equation. Morphological changes observed in the scanning electron micrograph of native and exhausted biomass indicate the existence of biosorption phenomenon. Fourier transform infrared spectrometry of exhausted leaf biomass highlights amino acid - Cr interactions responsible for sorption phenomenon. Regeneration of exhausted biomass was attempted for several cycles for its effective reusability.

2

Nitric oxide alleviates manganese toxicity by preventing oxidative stress in exised rice leaves

100%

Srivastava S. , Dubey R. S.

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nr 2

EN

In the present study, we have investigated the effects of nitric oxide (NO) on alleviating manganese (Mn)-induced oxidative stress in rice leaves. Exogenous MnCl₂ treatment to excised rice leaves for 24 and 48 h resulted in increased production of H₂O₂ and lipid peroxides, decline in the levels of antioxidants, glutathione and ascorbic acid, and increased activities of antioxidative enzymes, superoxide dismutase, guaiacol peroxidase, catalase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Treatment of rice leaves with 100 µM sodium nitroprusside (SNP), a NO donor, was effective in reducing Mn-induced increased levels of H₂O₂, lipid peroxides and increased activities of antioxidative enzymes. The levels of reduced ascorbate and glutathione were considerably recovered due to SNP treatment. The effect of SNP was reversed by the addition of NO scavenger, 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (c-PTIO) suggesting that ameliorating effect of SNP is due to release of NO. The results indicate that MnCl₂ induces oxidative stress in excised rice leaves, lowers the levels of reduced ascorbate and glutathione, and elevates activities of the key antioxidative enzymes. NO appears to provide a protection to the rice leaves against Mn-induced oxidative stress and that exogenous NO application could be advantageous in combating the deleterious effects of Mn-toxicity in rice plants.

3

Evaluation of effects of arsenic on carbon, nitrogen, and sulfur metabolism in two contrasting varieties of Brassica juncea

80%

Pathare V. , Srivastava S. , Suprasanna P.

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nr 12

EN

This study evaluated the effects of arsenic (As) exposure on carbon, nitrogen, and sulfur (CNS) metabolism in Brassica juncea. Two contrasting, tolerant (TPM-1) and sensitive (TM-4), varieties of B. Juncea were selected and grown either in control sand (150 g) or in sand containing 10 mg of arsenate. Harvesting was performed at 7 and 15 days and various metabolites and enzymes of CNS as well as γ-aminobutyric acid (GABA) metabolism were analyzed. At 7 days, TM-4 showed significantly higher As accumulation and stressed phenotype with increase in superoxide radicals, malondialdehyde, and cell death, as compared with TPM-1. However, the level of hydrogen peroxide was higher in TPM-1 than in TM-4. The level of GABA and the activity of glutamate decarboxylase increased in both roots and shoots of TPM-1, but not in TM-4. The level of nitrate and sulfate increased and decreased in shoots of TPM-1 and TM-4, respectively. The supply of fumarate and succinate was maintained in both shoots and roots of TPM-1 while it was only in shoots of TM-4. There was significant alteration in the profile of amino acids and in sulfur and nitrogen metabolism. However, at 15 days, As accumulation of both varieties was found to be similar along with an increase in GABA, nitrate, and sulfate in both shoots and roots except sulfate in TM-4. Supply of fumarate and succinate was also maintained and other responses were found to be similar in TPM-1 and TM-4. The study demonstrates that responses of CNS metabolism differ in varietal and time-dependent manner.

4

Arsenic accumulation in Ocimum spp. and its effect on growth and oil constituents

80%

Siddiqui F. , Krishna S. K. , Tandon P. K. , Srivastava S.

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nr 04

EN

A comparative evaluation of As accumulation and subsequent effects upon exposure to arsenite [As(III)] was performed in three species of Ocimum. Plants accumulated high amount of As (μg g-1 dry weight; dw) (662 in O. tenuiflorum, 764 in O. basilicum and 831 in O. gratissimum at 100 μM As(III) after 10 days) with the order of accumulation being roots[stem[leaves. A significant reduction in plant height and biomass was observed. However, essential oil yield and major oil constituents, such as eugenol, methyl chevicol, and linalool, increased at lower As(III) concentrations [mostly up to 25 μM As(III)] in all three species. Positively, no detectable amount of As was found in oil of any species. The study proposes that Ocimum may be used as a phytoremediator and at the same time as a source of essential oils under proper regulation.

5

Seasonal variation in abiotic factors and toxicity of thymol against the snail Lymnaea acuminata

80%

Srivastava S. , Kumar P. , Singh V. K. , Singh D. K.

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tom 03

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nr 1

6

Potential of Saraca indica leaf powder (SILP) for chromium removal from aqueous solution

80%

Goyal P. , Sharma P. , Srivastava S. , Srivastava M. M.

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tom Vol. 33, no. 2

35-44

EN

The paper projects the potential of agricultural waste Saraca indica leaf powder (SILP) in biosorbing chromium from aqueous system. The influence of pH, contact time, metal concentration, biomass dosage and particle size on the selectivity of the removal process was investigated. The maximum sorption efficiency of SILP for Cr(III): 85.23% and Cr(VI): 89.67% was found to be pH dependent giving optimum sorption at pH 6.5 and 2.5 respectively. The adsorption process fitted well to both Freundlich and Langmuir isotherms. Morphological changes observed in Scanning Electron Micrographs of metal treated biomass confirm the existence of biosorption phenomenon. Fourier Transform Infra-red Spectrometry confirms that amino acid-Cr interactions contribute a significant role in the biosorption of chromium using target leaf powder. The successful applications of easily abundant agricultural waste SILP, as a biosorbent have potential for a low technological pretreatment step, prior to economically not viable high-tech chemical treatments for the removal of Cr from water bodies.

7

Novel Coordination Complexes of the Trivalent Ruthenium, Rhodium and Iridium with Hydrazones Derived from Isatin Hydrazide and Various Aldehydes with Spectral and Biological Characterization

80%

Sharma V. , Srivastava S. , Srivastava A.

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2006

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tom Vol. 80, nr 3

387-396

EN

Aseries of several new ruthenium(III), rhodium(III) and iridium(III) complexes with hydrazones of general formula [M(LH)3]Cl3 were synthesized in order to meet requirements essential for biological properties. Hydrazones were formed by isatin hydrazide and various aldehydes namely anisaldehyde, benzaldehyde, o-chlorobenzaldehyde, p-chlorobenzaldehyde and p-fluorobenzaldehyde. Physicochemical characterization of compounds has been carried out by elemental analyses, spectroscopic (IR, electronic, 1H NMR), thermogravimetric and magnetic studies. These complexes show higher conductance values, supporting their electrolytic nature. All the studies revealed octahedral nature of the complexes with nitrogen and oxygen of azomethine and carbonyl group as binding sites and exhibited monomeric nature of the complexes. Rhodium(III) and iridium( III) complexes were found diamagnetic and show intense absorptions while ruthenium( III) complexes show paramagnetic behaviour. In addition, antifungal and antibacterial studies have been carried out in vitro for investigated compounds against fungus A. niger and F. oxysporium and bacteria E. coli and S. aureus. Most of the metal chelates show higher biocidal activity for the above microorganisms than that of the free ligand.

8

Adsorption behavior of cadmium and nickel from aqueous solution by Saraca indica leaf powder

70%

Srivastava M. M. , Chauhan A. , Kumari P. , Sharma P. , Srivastava S.

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nr 3