Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches u...Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches using multi-biosystems to achieve an enhanced bioremoval of Pb.The present study evaluated the capacity of a unique association of Pennisetum purpureum,a hyperaccumulator plant,and Lumbricus terrestris(earthworm)bioaugmented with a Pb-resistant bacterium,obtained from an industrially contaminated site and identified as isolate VITMVCJ1 Klebsiella variicola,to bioremediate Pb.The Pb-resistant gene was amplified in the bacterial isolate VITMVCJ1.The study was conducted for 60 d.Results verified that the bioaugmentation process enhanced1)root and shoot length of the plants,2)chlorophyll content of the plants,and 3)biofilm-producing ability of the microbes from the rhizosphere region of the plants.The total phenolic and flavonoid contents were found to be lower in the plants in the bioaugmented setup.The study also observed a reduction in the toxic effects of Pb on earthworm and plant.The earthworm was used to assess the Pb-induced stress syndrome after exposure to sublethal concentrations of Pb in the soil.A reduction in the content of malondialdehyde,a potential biomarker,on exposure to Pb demonstrated the role of the inoculum to alleviate heavy metal-induced stress in earthworms.All three symbionts accumulated Pb;Pb was accumulated mainly in the root of the plant,and poorly in the shoot of the plant and body mass of the earthworm.The bioaugmentation system exhibited stable and excellent uptake of Pb from the contaminated soils.The results of the present study suggest the positive effect of the synergistic association of the plant and earthworm with appropriate microbes for the bioremoval of Pb.展开更多
The burrowing and feeding activities of earthworms may have a strong effect on the flux of N2O from agricultural soils. As such, shifts to agricultural management practices that increase the number of earthworms requi...The burrowing and feeding activities of earthworms may have a strong effect on the flux of N2O from agricultural soils. As such, shifts to agricultural management practices that increase the number of earthworms require an understanding of the role of earthworms in N2O dynamics. We conducted a field experiment to examine the effects of addition of anecic earthworms (Lumbricus terrestris) on N2O flux in a field previously planted with corn (Zea mays) in southern Rhode Island, USA. Plots were amended with (15NH4)2SO4 and either 0 (CTL) or 48 L. terrestris m-2 (EW). The flux of N2O, 15N2O and 15N2 was measured over 28 days between October and November 2008. The EW treatment had a significantly higher flux of N2O and 15N2O 1 - 3 days after 15NH4 addition. No treatment effects were observed on 15N2 flux. The addition of earthworms significantly increased (Day 1) and decreased (Day 12) the mole fraction of N2O relative to the CTL. Our results suggest that anecic earthworm additions can increase N2O flux from inorganic fertilizer N amendments, but the effects appear to short-lived.展开更多
文摘Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches using multi-biosystems to achieve an enhanced bioremoval of Pb.The present study evaluated the capacity of a unique association of Pennisetum purpureum,a hyperaccumulator plant,and Lumbricus terrestris(earthworm)bioaugmented with a Pb-resistant bacterium,obtained from an industrially contaminated site and identified as isolate VITMVCJ1 Klebsiella variicola,to bioremediate Pb.The Pb-resistant gene was amplified in the bacterial isolate VITMVCJ1.The study was conducted for 60 d.Results verified that the bioaugmentation process enhanced1)root and shoot length of the plants,2)chlorophyll content of the plants,and 3)biofilm-producing ability of the microbes from the rhizosphere region of the plants.The total phenolic and flavonoid contents were found to be lower in the plants in the bioaugmented setup.The study also observed a reduction in the toxic effects of Pb on earthworm and plant.The earthworm was used to assess the Pb-induced stress syndrome after exposure to sublethal concentrations of Pb in the soil.A reduction in the content of malondialdehyde,a potential biomarker,on exposure to Pb demonstrated the role of the inoculum to alleviate heavy metal-induced stress in earthworms.All three symbionts accumulated Pb;Pb was accumulated mainly in the root of the plant,and poorly in the shoot of the plant and body mass of the earthworm.The bioaugmentation system exhibited stable and excellent uptake of Pb from the contaminated soils.The results of the present study suggest the positive effect of the synergistic association of the plant and earthworm with appropriate microbes for the bioremoval of Pb.
文摘目的 初步探讨蚯蚓与日本血吸虫间共同抗原。方法 用十二烷基硫酸钠 -聚丙烯酰胺凝胶电泳分析蚯蚓抗原 (L t Ag)和日本血吸虫成虫抗原 (Sj Ag)的蛋白组分 ;并将其蛋白组分分别与日本血吸虫病患者阳性血清和兔抗蚯蚓的免疫血清进行斑点酶联免疫吸附试验、免疫印迹试验。结果 L t Ag和 Sj Ag的蛋白组分间存在较多分子量相近的蛋白条带。L t Ag抗原分子量在 39～ 90 k Da范围内与日本血吸虫病患者血清的交叉反应尤其明显。Sj Ag也能与兔抗蚯蚓血清较好的结合。结论 实验结果提示 ,L t Ag与 Sj Ag之间存在着至少
文摘The burrowing and feeding activities of earthworms may have a strong effect on the flux of N2O from agricultural soils. As such, shifts to agricultural management practices that increase the number of earthworms require an understanding of the role of earthworms in N2O dynamics. We conducted a field experiment to examine the effects of addition of anecic earthworms (Lumbricus terrestris) on N2O flux in a field previously planted with corn (Zea mays) in southern Rhode Island, USA. Plots were amended with (15NH4)2SO4 and either 0 (CTL) or 48 L. terrestris m-2 (EW). The flux of N2O, 15N2O and 15N2 was measured over 28 days between October and November 2008. The EW treatment had a significantly higher flux of N2O and 15N2O 1 - 3 days after 15NH4 addition. No treatment effects were observed on 15N2 flux. The addition of earthworms significantly increased (Day 1) and decreased (Day 12) the mole fraction of N2O relative to the CTL. Our results suggest that anecic earthworm additions can increase N2O flux from inorganic fertilizer N amendments, but the effects appear to short-lived.
