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The aim of the study was to relate the effects of deficiency and excess of Mn with the generation of reactive oxygen species (ROS) and altered cellular redox environment in mulberry ( Morus alba L.) cv. Kanva-2 plants. Mn deficiency symptom appeared as mild interveinal chlorosis in middle leaves. Mn-excess did not produce any specific symptom. Leaf water potential ( Ψ) was increased in Mn-deficient and Mn-excess mulberry plants. Mn-deficient leaves contained less Mn, less chloroplastic pigments and high tissue Fe, Zn and Cu concentrations. Starch content was increased with increasing Mn supply. While reducing sugar content increased in Mn-deficient and Mn-excess plants as well, non-reducing sugars remained unaffected in Mn-deficient plants and decreased in Mn-excess plants. Moreover, study of antioxidative responses, oxidative stress (H 2O 2 and lipid peroxidation) and cellular redox environment [dehydroascorbate (DHA)/ascorbic acid (AsA) ratio] in Mn-stressed mulberry plants was also undertaken. Both hydrogen peroxide and lipid peroxidation were enhanced in the leaves of Mn-deficient plants. Increased H 2O 2 concentration in Mn-excess leaves did not induce oxidative damage as indicated by no change in lipid peroxidation. The ratio of the redox couple (DHA/AsA) was increased both in Mn-deficient or Mn-excess plants. The activities of superoxide dismutase (EC 1.15.1.1) and catalase (EC 1.11.1.6) increased in Mn-deficient plants. The activity of ascorbate peroxidase (EC 1.11.1.11) increased with increasing Mn supply. The results suggest that deficiency or excess of Mn induces oxidative stress through enhanced ROS generation and disturbed redox couple in mulberry plants. [ABSTRACT FROM AUTHOR]

A novel synthetic method for the preparation of different sorbent-polymer composite beads has been developed under simple laboratory conditions. Copper hexacyanoferrate was synthesized, and its composite beads of required size were synthesized by phase-inversion technique, using polyethersulfone as the polymer matrix. Suitable size and mechanical stability, along with their spherical shape, make these composite beads most appropriate for column operation. The efficiency of these composite beads was tested for the removal of cesium, using radioanalytical techniques, in batch conditions. The effect of pH, the initial metal ion concentration, and contact time was also investigated. The synthesized beads perform best in the pH range 5-9. Different sorption isotherm models were applied to the experimental data. Equilibrium data are represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 1.56 mg g−1 for the swollen beads. Kinetic modeling analysis, by fitting the data in the pseudo first-order, pseudo second-order, and intraparticle diffusion equations, shows that the pseudo second-order equation is the most appropriate model for the description of sorption of cesium ions onto the composite beads. The process mechanism is found to be complex, consisting of both intraparticle diffusion and film diffusion. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Maize plants (Zea mays L. cv. Ganga 2 and cv. Jaunpuri satha) were grown in solution culture under glasshouse conditions at deficient (0 µM) and normal (1 µM) levels of Zn supply. Appearance of visible effects characteristic of Zn deficiency, depression in plant growth, and dry matter yield of the plants indicated that Ganga 2 was more susceptible to Zn deficiency than Jaunpuri satha. Higher susceptibility of Ganga 2 to Zn deficiency was also manifested by a greater decrease in plant dry mass and an increased accumulation of TBARS (thiobarbituric acid reactive substance, describing lipid peroxidation). While total SOD activity was decreased in Zn deficient plants of Ganga 2, it was increased marginally in case of Jaunpuri satha. The marginal increase in total SOD activity in the Zn‐deficient Jaunpuri satha plants was a result of a marked increase in non‐CuZn SOD and only a slight decrease in CuZn SOD. Though Zn deficiency increased H2O2 concentration and the activities of H2O2‐scavenging enzymes in both the cultivars, there was less increase in H2O2 concentration and the activities of peroxidase, ascorbate peroxidase and glutathione reductase were more prominently increased in the Zn‐efficient Jaunpuri satha. Plants of the susceptible variety, Ganga 2, accumulated higher concentrations of glutathione disulfide. It is concluded that the significant decreases in the activities of CuZn SOD (CN‐sensitive SOD) and glutathione reductase, and high concentrations of H2O2 predisposed Zn‐deficient Ganga 2 plants to more severe oxidative stress than those of Jaunpuri satha and, therefore, contributed to a greater decrease in dry matter production. [ABSTRACT FROM AUTHOR]

The aim of the study was to induce B deficiency symptoms and to relate the generation of reactive oxygen species (ROS) and altered cellular redox environment with the effects of B deficiency in mulberry (Morus alba L.) cv. Kanva-2 plants. Study was undertaken on antioxidant responses, malondialdehyde (MDA) content as an indicator of oxidative damage and ratio of dehydroascorbate (DHA) to ascorbic acid (AsA) as an index of cellular redox environment in B-deficient (0.0 µM) and B-supraoptimal (33 µM) mulberry plants. B deficiency symptoms appeared as upward cupping of the young emerging leaves. Later on, B-deficient plants developed lenticels like cracks on major vein, petiole and stem. B-deficient leaves had higher water potential (Ψ) and relative water content (RWC), contained a lower concentration of B, less chloroplastic pigments and high tissue Fe, Mn and Zn concentrations compared to the controls. Hydrogen peroxide was accumulated in leaves of B-deficient and B-supraoptimal plants. B-supraoptimal plants also showed an increased DHA/AsA ratio. The activities of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and ascorbate peroxidase (APX, EC 1.11.1.11) were increased in B-deficient leaves. The activities of SOD and POD were decreased in B-supraoptimal plants. The results suggest that B deficiency aggravates oxidative stress through enhanced generation of ROS in mulberry plants. [ABSTRACT FROM AUTHOR]

Excess concentration of cobalt in the growth medium produced visual symptoms of toxicity that intensified with increasing level and duration of metal supply. The tissue concentration of cobalt increased with increasing level of supply. Decreased concentrations of chlorophylls and carotenoids and an increased carotenoids/chlorophyll ratio along with a marked increase in the activities of anti-oxidative enzymes, viz. superoxide dismutase (SOD), ascorbate peroxidase (APOD) and nonspecific peroxidase (POD) suggest strong induction of oxidative stress due to excess cobalt in the growth medium. Decrease in the activity of catalase (CAT)—an iron enzyme, may suggest interference of excess cobalt in iron metabolism of plants, particularly above a 50 μM supply. Decrease in hydrogen peroxide with an increase in cobalt supply has been attributed to increased activities of POD and APOD. Increase in dry matter yield of plants supplied 50 μM cobalt and the decrease in lipid peroxidation with increasing cobalt supply in the range 50–200 μM is suggested as a result from depletion of functional iron as phosphate and/or in ferritin. Appearance of the metal specific toxicity is the likely result of damages predominantly due to enhanced reactive oxygen species (ROS) generation at higher, 300–400 μM, cobalt supplies. [Copyright &y& Elsevier]

The photodissociation dynamics of 3-bromo-1,1,1-trifluoro-2-propanol (BTFP) and 2-(bromomethyl) hexafluoro-2-propanol (BMHFP) have been studied at 234 nm, and the C-Br bond dissociation investigated using resonance-enhanced multiphoton ionization coupled with time-of-flight mass spectrometer (REMPI-TOFMS). Br formation is a primary process and occurs on a repulsive surface involving the C-Br bond of BTFP and BMHFP. Polarization dependent time-of-flight profiles were measured, and the translational energy distributions and recoil anisotropy parameters extracted using forward convolution fits. A strong polarization dependence of time-of-flight profiles suggest anisotropic distributions of the Br(2P3/2) and Br(2P1/2) fragments with anisotropy parameter, β, of respectively 0.5 ± 0.2 and 1.2 ± 0.2 for BTFP, and 0.4 ± 0.1 and 1.0 ± 0.3 for BMHFP. The measured velocity distributions consist of a single velocity component. The average translational energies for the Br(2P3/2) and Br(2P1/2) channels are 9.2 ± 1.0 and 7.4 ± 0.9 kcal/mol for BTFP, and 15.4 ± 1.8 and 15.1 ± 2.0 kcal/mol for BMHFP. The relative quantum yields of Br(2P3/2) and Br(2P1/2), which are 0.70 ± 0.14 and 0.30 ± 0.06 in BTFP and 0.81 ± 0.16 and 0.19 ± 0.04 in BMHFP, indicate that the yield of the former is predominant. The measured anisotropy parameters for the Br(2P3/2) and Br(2P1/2) channels suggest that the former channel has almost equal contributions from both the parallel and the perpendicular transitions, whereas the latter channel has a significant contribution from a parallel transition. Non-adiabatic curve crossing plays an important role in the C-Br bond dissociation of both BTFP and BMHFP. The estimated curve crossing probabilities suggest a greater value in BTFP, which explains a greater observed value of the relative quantum yield of Br(2P1/2) in this case. [ABSTRACT FROM AUTHOR]

Abstract: A novel method of synthesis of spherical resorcinol–formaldehyde resin was developed, using calcium alginate beads as template. Batch sorption experiments were carried out, to remove cesium ions from aqueous alkaline solutions, using the synthesized resin beads. The effect of operating variables, such as the initial cesium ion concentration, sodium ion concentration, and contact time, on the sorption of cesium ions was studied. Equilibrium data were found to fit better to Langmuir isotherm equation, with a monolayer sorption capacity of 490.2mg/g, and the complete elution of the sorbed cesium ions was also possible. Sorption data were also analyzed in terms of both Lagergren first-order and pseudo second-order kinetic models, and were found to follow pseudo second-order kinetics at lower initial cesium ion concentration. The kinetic parameters were determined at different initial concentrations. The process mechanism was found to be complex, consisting of both film diffusion and intraparticle diffusion. Sorption data were also analyzed, using a Boyd plot, which confirmed that the rate-limiting step is the film diffusion. [Copyright &y& Elsevier]

Abstract: The photodissociation dynamics of 2-furoyl chloride at 235nm has been investigated, employing resonance-enhanced multiphoton ionization technique and time-of-flight mass spectrometry. Both the Cl fragments, Cl(2 PJ= 3/2, relative quantum yield 0.85±0.11) and Cl∗(2 PJ =1/2), have the recoil anisotropy parameter (β) value close to zero, and show bimodal translational energy distributions. The branching ratio of the high kinetic energy Ccission to the low energy Con is 0.78/0.22. The dominant high kinetic energy channel arises mainly because of electronic pre-dissociation. But, the low energy channel results from the ground electronic state of 2-furoyl chloride, formed subsequent to non-radiative relaxation of the initially prepared excited state. [Copyright &y& Elsevier]

Abstract: Mesoporous titanium dioxide microspheres were synthesized by the sol–gel templating method, using calcium alginate as a sacrificial template, and subjecting to different temperatures, under various atmospheres. The gradual changes in composition, crystallinity, phase and surface morphology, due to variation in calcination atmosphere and temperature, were monitored by TGA, XRD, SEM and EDX techniques. The effect of polymeric content on the surface area and the pore size of the titania beads was evaluated by BET analysis. The results show that N2 atmosphere and high temperature influence the phase content and morphology of the microsphere significantly. Anatase to rutile phase transformation and formation of calcium titanate take place under nitrogen atmosphere at lower temperature, as compared to that under air atmosphere. To examine the applications of these synthesized microspheres, photo-catalytic activity and sorption efficiency of the microspheres were evaluated, by carrying out photo-degradation of methylene blue (MB) dye, and removal of arsenic ions from ammoniacal solution. The microspheres showed good photo catalytic activity towards MB dye. Tracer experiments with 76As showed ∼98% sorption of arsenic ions from aqueous solution onto the titania microspheres. [Copyright &y& Elsevier]

Abstract: Studies were made to relate signs of oxidative stress in chlorotic and non-chlorotic leaves of plants receiving deficient supply, either nil (chlorotic leaves) or 10μM (non-chlorotic leaves) of Fe, with thiobarbituric acid reactive substance (TBARS) and Fe status of leaf tissues. Total Fe concentration in the young leaves of mulberry, maize and cauliflower plants supplied deficient Fe did not show any significant change. Deficient supply of Fe caused decreases in the activities of catalase, peroxidase and ascorbate peroxidase and increases in the activity and number of isoforms of superoxide dismutase (SOD), accumulation of superoxide anion radical (O2 −) and concentration of H2O2 in the young leaves of each mulberry, maize or cauliflower plants. While the chlorotic leaves of Fe-starved mulberry, maize and cauliflower plants had significantly lower TBARS compared to green leaves of the controls or non-chlorotic leaves of cauliflower plants supplied low Fe (10μM). While TBARS concentration in the young leaves of these plants was well correlated with the concentrations of chloroplastic pigments, and activities of catalase and ascorbate peroxidase, its relationship with leaf tissue Fe or H2O2 concentration was rather poor. Progressive increase in the activity and induction of new isoforms of SOD and higher accumulation H2O2 and O2 − may be considered as signs of oxidative stress, whereas, increased ascorbate content along with lower mole fraction of ascorbic acid/total ascorbate are indicative of disturbed cellular redox environment in Fe-starved plants. It is concluded that chlorotic leaves of Fe-starved plants though have elevated titre of reactive oxygen species they are less susceptible to oxidative damage probably due to lower chloroplastic pigments/or low functional Fe in the tissue. [Copyright &y& Elsevier]

Kinetics of reaction of OH radical with morpholine, a heterocyclic molecule with both oxygen and nitrogen atoms, has been investigated using laser photolysis-laser-induced fluorescence technique, in the temperature range of 298-363 K. The rate constant at room temperature (k(298)) is (8.0 +/- 0.1) x 10(-11) molecule(-1) cm(3) s(-1). The rate constant decreases with temperature in the range studied, with the approximate dependence given by k(T) = (1.1 +/- 0.1) x 10(-11) exp[(590 +/- 20)/T] cm(3) molecule(-1) s(-1). The rate constants are high compared with those of similar heterocyclic molecules with oxygen atom but comparable to those reported for aliphatic amines. Ab initio molecular orbital calculations show that prereactive complexes, 5-7 kcal mol(-1) lower in energy as compared with the reactants, are formed because of hydrogen bond interaction between OH and the N/O atom of morpholine. The stability of the complex involving the nitrogen atom is found to be more than that involving the oxygen atom. The optimized transition-state structures and energies for the different pathways of hydrogen abstraction from these prereactive complexes explain the observation of negative activation energy.

Dynamics of formation of electronically excited NO2 and formation of OH fragment, during photo dissociation of 2-nitropropane (NP) and 2-methyl-2-nitropropane (MNP), were investigated at 193 and 248 nm. The radiative lifetime of the electronically excited NO2 fragment, observed at 193 nm, was measured to be 1.2 ( 0.1 micros and the rate coefficient of quenching of its emission by MNP was measured as (2.7 ( 0.1) x 10(-10) molecule(-1) cm3 s(-1). Formation of the ground electronic state of OH was confirmed in both molecules. State selective laser induced fluorescence technique was used to detect the nascent OH (X 2Pi, v'', J'') fragments in different ro-vibrational states, and to obtain information on energy partitioning. Though MNP and NP differ in the types of the available H atoms, the dynamics of OH formation is found to be the same in both. The relative population in different rotational states does not follow Boltzmann equilibrium distribution in both the molecules at 193 and 248 nm. The translational energies of the OH fragments, calculated from the Doppler width, are 21.2 ( 7.2 and 25.0 ( 2.5 kcal mol-1 for NP at 248 and 193 nm, respectively. The translational energies of the OH fragments, in the case of MNP, are found to be lower, 17.5 ( 4.1 and 22.0 ( 3.2 kcal mol-1,respectively, at 248 nm 193 nm. These results are compared with the earlier reports on photodissociation of nitromethane (NM), nitroethane (NE), and other nitroalkanes. All possible dissociation pathways of these molecules--NM, NE, NP, and MNPs leading to the formation of the OH fragment were investigated computationally, with geometry optimization at the B3LYP/6-311+G(d,p) level and energy calculation at the MP4(SDQ)/6-311+G (d,p) level. The results suggest that in NM, OH is formed after isomerization to CH2N(OH)O, whereas in all other cases OH is formed from HONO, a primary product of molecular elimination of nitroalkanes, formed with sufficient internal energy.

In this study, we examined the modulation of Cu toxicity-induced oxidative stress by excess supply of iron in Zea mays L. plants. Plants receiving excess of Cu (100 microM) showed decreased water potential and simultaneously showed wilting in the leaves. Later, the young leaves exhibited chlorosis and necrotic scorching of lamina. Excess of Cu suppressed growth, decreased concentration of chloroplastic pigments and fresh and dry weight of plants. The activities of peroxidase (EC 1.11.1.7; POD), ascorbate peroxidase (EC 1.11.1.11; APX) and superoxide dismutase (EC 1.15.1.1; SOD) were increased in plants supplied excess of Cu. However, activity of catalase (EC 1.11.1.6; CAT), was depressed in these plants. In gel activities of isoforms of POD, APX and SOD also revealed upregulation of these enzymes. Excess (500 microM)-Fe-supplemented Cu-stressed plants, however, looked better in their phenotypic appearance, had increased concentration of chloroplastic pigments, dry weight, and improved leaf tissue water status in comparison to the plants supplied excess of Cu. Moreover, activities of antioxidant enzymes including CAT were further enhanced and thiobarbituric acid reactive substance (TBARS) and H(2)O(2) concentrations decreased in excess-Fe-supplemented Cu-stressed plants. In situ accumulation of H(2)O(2), contrary to that of O(2)(*-) radical, increased in both leaf and roots of excess-Cu-stressed plants, but Cu-excess plants supplied with excess-Fe showed reduced accumulation H(2)O(2) and little higher of O(2)(*-) in comparison to excess-Cu plants. It is, therefore, concluded that excess-Cu (100 microM) induces oxidative stress by increasing production of H(2)O(2) despite of increased antioxidant protection and that the excess-Cu-induced oxidative damage is minimized by excess supply of Fe.

The aim of the study was to implicate the generation of reactive oxygen species (ROS) and altered cellular redox environment with the effects of Cu-deficiency or Cu-excess in mulberry (Morus alba L.) cv. Kanva 2 plants. A study of antioxidative responses, indicators of oxidative damage and cellular redox environment in Cu-deficient or Cu-excess mulberry plants was undertaken. While the young leaves of plants supplied with nil Cu showed chlorosis and necrotic scorching of laminae, the older and middle leaves of plants supplied with nil or 0.1 microM Cu showed purplish-brown pigmented interveinal areas that later turned necrotic along the apices and margins of leaves. The Cu-excess plants showed accelerated senescence of the older leaves. The Cu-deficient plants showed accumulation of hydrogen peroxide and superoxide anion radical. The accumulation of hydrogen peroxide was strikingly intense in the middle portion of trichomes on Cu-deficient leaves. Though the concentration of total ascorbate increased with the increasing supply of Cu, the ratio of the redox couple (DHA/ascorbic acid) increased in Cu-deficient or Cu-excess plants. The activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7), ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2) increased in both Cu-deficient and Cu-excess plants. The results suggest that deficiency of Cu aggravates oxidative stress through enhanced generation of ROS and disturbed redox couple. Excess of Cu damaged roots, accelerated the rate of senescence in the older leaves, induced antioxidant responses and disturbed the cellular redox environment in the young leaves of mulberry plants.