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Molecular characterization of conjugative plasmids in pesticide tolerant and multi-resistant bacterial isolates from contaminated alluvial soil 总被引:1,自引:0,他引:1
A total of 35 bacteria from contaminated soil (cultivated fields) near pesticide industry from Chinhat, Lucknow, (India) were isolated and tested for their tolerance/resistance to pesticides, heavy metals and antibiotics. Bacterial isolates were identified by 16S rDNA sequencing. Gas Chromatography analysis of the soil samples revealed the presence of lindane at a concentration of 547 ng g−1 and α-endosulfan and β-endosulfan of 422 ng g−1 and 421 ng g−1 respectively. Atomic Absorption Spectrophotometry analysis of the test sample was done and Cr, Zn, Ni, Fe, Cu and Cd were detected at concentrations of 36.2, 42.5, 43.2, 241, 13.3 and 11.20 mg kg−1 respectively. Minimum inhibitory concentrations of all the isolates were determined for pesticides and heavy metals. All the multi-resistant/tolerant bacterial isolates were also tested for the presence of incompatibility (Inc) group IncP, IncN, IncW, IncQ plasmids and for rolling circle plasmids of the pMV158-family by PCR. Total community DNA was extracted from pesticide contaminated soil. PCR amplification of the bacterial isolates and soil DNA revealed the presence of IncP-specific sequences (trfA2 and oriT) which was confirmed by dot blot hybridization with RP4-derived DIG-labelled probes. Plasmids belonging to IncN, IncW and IncQ group were neither detected in the bacterial isolates nor in total soil DNA. The presence of conjugative or mobilizable IncP plasmids in the isolates indicate that these bacteria have gene transfer capacity with implications for dissemination of heavy metal and antibiotic resistance genes. We propose that IncP plasmids are mainly responsible for the spread of multi-resistant bacteria in the contaminated soils. 相似文献
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Mehdi Sheikh Goodarzi Yousef Sakieh Shabnam Navardi 《Environment, Development and Sustainability》2017,19(3):1103-1126
Being located in an urban-coastal coupled system, the Hashtpar City is one of the most attractive areas for urban construction, tourism, agricultural activities and environmental protection in northern Iran. To resolve the issues between land developers and environmental conservation agencies, we conducted a scenario-based urban growth allocation procedure through the SLEUTH model. The scenarios consisted of ‘business as usual’, ‘managed urban growth’ and ‘environmentally sound growth’ that were introduced by modification of model parameters and exclusion layer. The resultant urban growth arrangements were compared for composition and configuration attributes of landscape patterns. According to the results, the pattern of urbanized lands under managed urban growth option demonstrated better connectivity and compactness of urban patches, while the two other scenarios generated a highly fragmented pattern. The managed urban growth can be considered as a compromised solution between other scenarios since it simultaneously takes into accounts both developers and environment protectors points’ of views. On this basis, a combination of centralized and decentralized urban land use planning is a recommended strategy for our urban-coastal environment to fulfill the purposes of a sustainable development process. The findings of the present article suggest that further expansion of the major urban core in the targeted area should be prohibited since it can lead to an urban patch with considerable physical size and noticeable ecological footprint. 相似文献
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Reshma JK Thanga VS 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(1):133-137
The retting environment which provides a competitive niche for specialized microbes is speculated to harbour a variety of microbes with high biodegradation potential. In this context, an effort has been made to isolate and identify bacterial species having high tolerance to phenol In vitro. Maximum polyphenol (1.897 mg l(-1)) as observed during the initial period of retting, which decreased as retting proceeded. Based on biochemical characterization, the isolated bacterial strains were identified as Micrococcus sp., Moraxella sp. strain MP1, Moraxella sp. strain MP2 and Moraxella sp. strain MP3, Pseudomonas sp. strain PP1 and Pseudomonas sp. strain PP2, Amphibacillus sp., Brucella sp. strain BP1 and Brucella sp. strain BP2, Aquaspirillum sp., Escherichia coli strain EP1 and Escherichia coli strain EP2, Campylobacter sp., Aeromonas sp., Neisseria sp., Vibrio sp., Erwinia sp. and Mesophilobacter sp. These strains were found to tolerate maximum concentration of phenol viz. 200 to 1000 mg l(-1). Plasmid analysis of phenol resistant bacterial isolates showed that almost all the cultures had at least one plasmid of size > 1Kb. Studies on the protein profile of isolated bacterial cultures showed the presence of proteins with molecular sizes ranging from 10 to 85 KDa with exception of Mesophilobacter and Neisseria having still high molecular weight protein (95 KDa). Bacterial strains isolated from coir-ret-liquor showed tolerance to high phenol concentration. 相似文献
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Hossein Reza Darabi Shabnam Mohandessi Yadollah Balavar Mojtaba Mirhosseini Moghaddam Kioumars Aghapoor Farshid Mohsenzadeh Abbas Ali Nourinia 《Environmental Chemistry Letters》2011,9(4):519-524
Pre-harvest sprouting refers to the precocious germination of the grain in the spike prior to harvest as a result of moist
weather conditions at harvest time. From the agricultural viewpoint, it is necessary to impose an exogenous dormancy to wheat
seeds in order to improve the resistance of seed to pre-harvest sprouting. In this regard, we found that clove bud essential
oil is a strong inhibitor for wheat seed germination. The extract obtained from clove bud by supercritical fluid extraction
using CO2 as solvent minimized the number of extracts to two compounds, eugenol and eugenyl acetate. Eugenol, as the main constituent
of the oil, was responsible for its strong inhibitory activity in wheat seeds. The aqueous solution of clove bud oil was submitted
to germination assay at various concentrations from 50 to 400 mg/L. Complete inhibition of seed germination was recorded when
the concentration was 400 mg/L. Roots and sprouts have similar sensitivity to inhibitory effect. In an empirical study, the
synergistic cooperation of eugenol and eugenyl acetate from clove bud oil in the inhibition of seed germination was found
to be a 1:1 ratio. The clove bud essential oil is widely available and will broaden the horizon of applications for natural
and safe inhibitors in the fields. 相似文献
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Phytoremediation is a sustainable process in which green plants are used for the removal or elimination of contaminants in soils. Both organic and inorganic contaminants can be removed or degraded by growing plants by several mechanisms, namely phytoaccumulation, phytostabilization, phytodegradation, rhizofiltration and rhizodegradation. Phytoremediation has several advantages: it can be applied in situ over large areas, the cost is low, and the soil does not undergo significant damages. However, the restoration of a contaminated site by phytoremediation requires a long treatment time since the remediation depends on the growth and the biological cycles of the plant. It is only applicable for shallow depths within the reach of the roots, and the remediation efficiency largely depends on the physico-chemical properties of the soil and the bioavailability of the contaminants. The combination of phytoremediation and electrokinetics has been proposed in an attempt to avoid, in part, the limitations of phytoremediation. Basically, the coupled phytoremediation–electrokinetic technology consists of the application of a low intensity electric field to the contaminated soil in the vicinity of growing plants. The electric field may enhance the removal of the contaminants by increasing the bioavailability of the contaminants. Variables that affect the coupled technology are: the use of AC or DC current, voltage level and mode of voltage application (continuous or periodic), soil pH evolution, and the addition of facilitating agents to enhance the mobility and bioavailability of the contaminants. Several technical and practical challenges still remain that must be overcome through future research for successful application of this coupled technology at actual field sites. 相似文献
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Marzieh Hadipour Shabnam Saffarian Mohsen Shafiee Soode Tahmasebi 《Journal of Material Cycles and Waste Management》2014,16(4):747-752
One of the requirements for development of human societies is the establishment of new healthcare centers. A variety of wastes are generated in healthcare centers depending on the type of activities. This study was conducted to identify, measure and manage different types of hospital wastes as a case study in a hospital located in southern Iran. For this purpose, a questionnaire was initially designed and distributed among the relevant experts to survey the current trend of waste management in the hospital in terms of waste collection, storage and disposal. Afterwards, the hospital waste was sampled during two seasons of fall and winter. The samples were weighted for seven consecutive days in the middle of each season. Approximately, 10 % of the total waste bags per day collected round the clock were selected for further analysis. The obtained results indicated that infectious-hazardous and pseudo-household wastes were, respectively, about 3.79 kg/day/bed, 1.36 kg/day/bed and 2.43 kg/day/bed of the total generated waste in the hospital. As the research findings suggest, proper separation of infectious and pseudo-household wastes at the source would be an essential step towards mitigating environmental and health risks and minimizing the cost of the hospital waste management. 相似文献
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Zinc oxide nanoparticles (ZnO2), a common ingredient of cosmetics has a huge variety of applications. Previous studies reported oxidative stress mediated toxicity of ZnO2 nanoparticles on various mammalian cell lines. Although zinc (Zn) is an essential mineral at higher concentrations this metal is toxic. The present study focused on size determination by monitoring changes in activities of antioxidant defense mechanism in response to oxidative stress induced by ZnO2 nanoparticles using mouse liver tissue homogenates. The study also investigated effects of oxidative stress induced DNA damage by determining formation of 8-OHdG in mouse liver homogenate. A cytotoxicity assay was also carried out in L929 cells to determine cell viability. The results of the study indicated that 50μg/ml of ZnO2 nanoparticles induced 50% cell death. Alterations in antioxidant parameters and 8-OHdG were also noted. Data showed that there was a concentration-dependent fall in cell viability, decrease antioxidant enzyme levels and increase formation of DNA adduct (8-OHdG) when mouse liver tissue homogenate were exposed to ZnO2 nanoparticles. 相似文献
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Qureshi S Richards BK Steenhuis TS McBride MB Baveye P Dousset S 《Environmental pollution (Barking, Essex : 1987)》2004,132(1):61-71
Leaching of sludge-borne trace elements has been observed in experimental and field studies. The role of microbial processes in the mobilization of trace elements from wastewater sludge is poorly defined. Our objectives were to determine trace element mobilization from sludge subjected to treatments representing microbial acidification, direct chemical acidification and no acidification, and to determine the readsorption potential of mobilized elements using calcareous sand. Triplicate columns (10-cm diameter) for incubation and leaching of sludge had a top layer of digested dewatered sludge (either untreated, acidified with H2SO4, or limed with CaCO3; all mixed with glass beads to prevent ponding) and a lower glass bead support bed. Glass beads in the sludge layer, support layer or both were replaced by calcareous sand in four treatments used for testing the readsorption potential of mobilized elements. Eight sequential 8-day incubation and leaching cycles were operated, each consisting of 7.6 d of incubation at 28 degrees C followed by 8 h of leaching with synthetic acid rain applied at 0.25 cm/h. Leachates were analyzed for trace elements, nitrate and pH, and sludge layer microbial respiration was measured. The largest trace element, nitrate and S losses occurred in treatments with the greatest pH depression and greatest microbial respiration rates. Cumulative leaching losses from both microbial acidification and direct acidification treatments were > 90% of Zn and 64-80% of Cu and Ni. Preventing acidification with sludge layer lime or sand restricted leaching for all trace elements except Mo. Results suggested that the primary microbial role in the rapid leaching of trace elements was acidification, with results from direct acidification being nearly identical to microbial acidification. Microbial activity in the presence of materials that prevented acidification mobilized far lower concentrations of trace elements, with the exception of Mo. Trace elements mobilized by acidification were readsorbed by calcareous sand when present. 相似文献
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The Journal of Safety Research has partnered with the National Center for Injury Prevention and Control at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA, to briefly report on some of the latest findings in the research community. This report is the fifth in a series of CDC articles. 相似文献