Usha Mina

PURIFICATION AND CHARACTERIZATION OF A THERMOSTABLE SOLUBLE PEROXIDASE FROM Citrus medica LEAF

A soluble and thermostable peroxidase enzyme (POD) was extracted from the leaf of Citrus medica. The enzyme was purified 15.10-fold with a total yield of 28.6% by ammonium sulfate precipitation followed by Sephadex G-100 gel filtration chromatography. The purified enzyme came as a single band on native polyacrylamide gel electrophoresis (PAGE) as well as sodium dodecyl sulfate (SDS) PAGE. The molecular mass of the enzyme was about 32 kD as determined by SDS-PAGE. The enzyme was optimally active at pH 6.0 and 50°C temperature. The enzyme was active in wide range of pH (5.0–8.0) and temperature (30–80°C). From the thermal inactivation studies in the range of 60–75°C, the half-life (t1/2) values of the enzyme ranged from 8 to 173 min. The inactivation energy (Ea) value of POD was estimated to be 21.7 kcal mol−1. The Km values for guaiacol and H2O2 were 8 mM and 1.8 mM, respectively. This enzyme was activated by some metals and reagents such as Ca2+, Cu2+, Mg2+, Co2+, ferulic acid, and indole acetic acid (IAA), while it was inhibited by Fe2+, Zn2+, Hg2+, and Mn2+, L-cysteine, L-proline, and protocatechuic acid.

Statistical modeling of O3, NOx, CO, PM2.5, VOCs and noise levels in commercial complex and associated health risk assessment in an academic institution

Indoor Air Quality (IAQ) is considered to be of great concern due to its adverse impact on the human health nowadays. The presence of different air pollutants along with noise may aggravate the IAQ. The present study attempts to examine IAQ in terms of major criteria air pollutants (O3, NOx=NO+NO2, CO and PM2.5) along with total volatile organic compound (TVOC), individual VOC and noise pollution in indoor and outdoor environment of a Commercial Shopping Complex (CSC) in Delhi. Real time measurements have been carried out for O3, NOx, CO, PM2.5, TVOC and noise while thirteen individual VOCs have been estimated using NIOSH method was performed using Gas Chromatograph. The study also aimed to find out the relationship among VOCs, source estimation using Principal Component Analysis. The observed results for the targeted pollutants were also compared with international and national recommended permissible values. The mean values of O3, NOx, CO, PM2.5 and TVOC are found to be 17.6/(15.0) ppb, 15.8/(14.1) ppb, 8.4/(1.9) ppm, 125.4/(74.6) μg/m3 and 412.5/(226.5) μg/m3 for indoor/(outdoor), respectively. Among the individual VOC, toluene was the most abundant followed by xylene-isomers and benzene. The noise pollution level in Indoor/outdoor were found to be 51.5/46.4dB which is below the guideline value (65dB) provided by the WHO. Most of the pollutants were found to have indoor sources. The different kinds of pollutants and noise may have synergistic effect and aggravate the health of the people working and visiting the CSC.

Effect of ozone exposure on growth, yield and isoprene emission from tomato (Lycopersicon esculentum L.) plants.

Effect of Ozone Exposure on Growth, Yield and Isoprene Emission from Tomato (Lycopersicon esculentum L.) Plants Effect of ozone on three different growth phase of tomato (Lycopersicon esculentum cv. Pusa ruby) crop namely, Early Vegetative Phase (EVP), 30 days old plants; Late Vegetative Phase (LVP), 45 days old plants; and Fruiting Phase (FP), 60 days old plants were exposed to ozone concentrations (75 ppb and 150 ppb) in closed top dynamic chambers for 12 days period. Ozone exposed tomato plants of all the three growth stages exhibited visible injury symptoms as chlorotic spots in variable intensity. Effect of ozone exposure on tomato crop plants was examined with respect to isoprene emission, growth and yield parameters. Enhancement in isoprene emission was observed from ozone exposed tomato plants as compared to unexposed plants. In exposed plants of early vegetative phase isoprene emission was 127% and 187% higher immediately after (within 1 hr) 75 ppb and 150 ppb ozone exposure respectively as compared to unexposed plants. Significant (p≤0.001) reduction in ozone exposed plants shoot length (2 to 10.5%), chlorophyll content (7 to 39%), carotenoids contents (5 to 42%), shoot biomass (upto 44%) and root biomass (8 to 65%) were observed as compared to unexposed plant. It was found that ozone exposure was more detrimental to LVP in comparison to FP and EVP. The results of the study also showed that 150 ppb of ozone exerted more harmful effects on the growth of different growth phases of tomato plants than 75 ppb ozone. Wpływ Ozonu na Wzrost, Plonowanie i Emisję Izoprenu u Roślin Pomidora (Lycopersicon Esculentum L.) Badano wpływ ozonu na trzy odmienne fazy wzrostu roślin pomidora (Lycopersicon esculentum odm. Pusa ruby), a mianowicie: Wczesną Fazę Wegetacji (WFW) - rośliny 30-to dniowe; Późną Fazę Wegetacji (PFW) - rośliny 45-cio dniowe; oraz Fazę Owocowania (FO) - rośliny 60-cio dniowe. Rośliny były wystawione na działanie ozonu w stężeniu 75 ppb i 150 ppb, w zamkniętych od góry komorach dynamicznych, przez okres 12 dniu. We wszystkich trzech fazach wzrostu, rośliny poddane działaniu ozonu miały widoczne objawy uszkodzeń w formie plam chlorotycznych o różnej intensywności. Wpływ ozonu na rośliny pomidora badano pod względem emisji izoprenu oraz parametrów wzrostu i owocowania. Zaobserwowano zwiększoną emisję izoprenu z roślin pomidora poddanych działaniu ozonu w porównaniu z roślinami kontrolnymi. W przypadku roślin traktowanych ozonem we wczesnej fazie wegetacji emisja izoprenu była o 127% i 187% wyższa, odpowiednio dla stężeń 75 ppb i 150 ppb, tuż po wystawieniu ich na działanie ozonu (w przeciągu 1 godz.) w porównaniu z roślinami nietraktowanymi. Odnotowano istotne (p≤0.001) zmniejszenie parametrów wzrostu w roślinach traktowanych ozonem, takich jak: długość pędów (2 do 10,5%), zawartość chlorofilu (7 do 39%), zawartość karotenoidów (5 do 42%), biomasa pędów (do 44%) w porównaniu z roślinami kontrolnymi. Stwierdzono bardziej szkodliwy wpływ ozonu na rośliny w późnej fazie wegetacji niż w fazie owocowania i wczesnej fazie wegetacji. Wyniki badań wykazały również, że stężenie ozonu w wysokości 150 ppb wywierało bardziej szkodliwy wpływ na wzrost roślin pomidora w różnych fazach wegetacji niż stężenie 75 ppb.

Rice Crop Growth and Rhizospheric Microbial Dynamics in Heavy Metals Contaminated Inceptisol

A glasshouse pot culture study was carried out with the aim to assess the potential toxic effects of heavy metals (Cr, Ni, Cd, Hg, and Pb) on two rice varieties (Pusa 44 and PB1509). Heavy metals get accumulated in different parts of rice plant (Oryza sativa L.) including the grains. The highest concentration of heavy metals in this study was in the roots observed rather than shoots and grains in both the rice varieties. Soil-to-grain transfer factor for non basmati rice for Ni, Pb, Cd, Cr, and Hg was 0.070, 0.028, 0.079, 0.0058, and 0.0049, respectively, and for basmati rice for Ni, Pb, Cd, Cr, and Hg was 0.065, 0.023, 0.072, 0.0050, and 0.0038, respectively. Average microbial population was more in the rhizosphere of Pusa 44 as compared to PB1509 under control condition. The viable population of bacteria, fungi, and actinomycetes was adversely affected by increasing concentration of each heavy metal. Mycorrhizal colonization was low on roots of Pusa 44 and PB1509 under metal treatments as compared to control and was minimum (22–26%) under Hg treatment.

Effect of Ozone on Biotic Stress Tolerance Potential of Wheat

Ozone (O3) is generated as an air pollutant in the troposphere in a photochemical reaction by the action of sunlight on volatile organic compounds and oxides of nitrogen emitted by vehicles and industry. O3 concentration in troposphere is rising at an annual rate of 0.5 % (IPCC, 2007) over its background concentration of 10–20 ppb. According to IPCC 4th assessment report (2007), current tropospheric O3 concentrations over the northern hemisphere in summers are about 30–40 ppb and are expected to rise upto 70 ppb in 2100. Elevated levels of O3 present in troposphere are phytotoxic and directly affects plants by reacting with apoplastic leaf components and forming reactive oxygen species (ROS) like hydroxyl (OH−), peroxyl (OH2−) and superoxide (O2 −) radicals (Fiscus et al., 2005). This oxidative burst causes loss of photosynthetic activity and reduced growth and yield of crops (Fiscus et al., 2005). Economic crop losses due to O3 were equivalent to

Effect of Bt Cotton on Enzymes Activity and Microorganisms in Rhizosphere

17-

Spatial and temporal variability of VOCs and its source estimation during rush/non-rush hours in ambient air of Delhi, India

82 million in US, 310 million euros in Netherlands and

Winter Fog Experiment Over the Indo-Gangetic Plains of India

2 billion in China (Mauzerall and Wang, 2001). In India also O3 phytotoxic impacts on growth and yield of several crops were reported (Varshney and Rout, 1998, Tiwari et al., 2005; Mina et al., 2010). O3 also influences plant’s susceptibility to biotic stress such as pathogens which causes diseases. Plants have innate mechanisms to protect them from various abiotic and biotic stresses. However the dual stress imposed by O3 and pathogen affects tolerance of crop and leads to altered host pathogen interaction (Fuhrer, 2003). Alteration in pathogenesis potential of pest due to O3 exposure is of ecological and economical importance.