Please use this identifier to cite or link to this item: http://hdl.handle.net/10603/407772
Title: Molecular analysis of diversity dynamics and activity of total and free living nitrogen fixing bacterial communities in arsenic contaminated agricultural soil
Researcher: Chakraborty, Arindam
Guide(s): Islam, Ekramul
Keywords: Arsenic
DNA
Life Sciences
Microbiology
University: University of Kalyani
Completed Date: 2018
Abstract: Arsenic (As) contamination in agricultural land is a serious issue as it increases the risk of Astranslocation newlineto crop plants as well as reduces soil fertility. The reduction of soil fertility might be newlinedue to perturbation of soil microbial community as a consequence of As contamination. Through newlinemicrobial community survey and couple of in vivo and in vitro experiments, the effect of such Ascontamination newlineon diversity, distribution of total and free-living diazotrophs and their activity in newlineterms of nifH gene expression in agricultural soil was investigated. Study was conducted at three newlinedifferent levels; comparison of microbial community in agricultural fields having different newlineconcentration of As, setting up laboratory microcosms amending different level of As and newlinebacterial isolates exposed to different concentration of As. Culture-independent molecular method newlinewas used to compare microbial communities. Both DNA and RNA from samples with different newlinedegrees of As level and from As exposed and unexposed bacterial isolates were extracted. newlineExtracted RNA was converted to cDNA. Microbial community of two different rice fields was newlineassessed during a cultivation period that includes tillage, tillering and post-harvesting by 16S newlinerRNA and nifH genes based clone library analyses and DNA sequencing. The data of clone library newlineanalysis indicated the abundance of copiotrophic Proteobacterial lineages in As contaminated soil newlinewhile Acidobacteria were prevalent in the soil without As contamination. This data also indicated newlinediverse nifH gene bearing unidentified bacteria in arsenic-rich soil but this does not imply all nifH newlinegenes bearing bacteria actually express dinitrogenase. Real time PCR analyses based on 16S newlinerRNA and nifH gene revealed elevated levels of total and nitrogen fixers in the agricultural land newlinewithout As contamination history through the cultivation period than As-contaminated land. newline
Pagination: xi, 96p.
URI: http://hdl.handle.net/10603/407772
Appears in Departments:Microbiology

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02_declaration.pdf244.94 kBAdobe PDFView/Open
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04_acknowledgement.pdf189.91 kBAdobe PDFView/Open
05_content.pdf323.85 kBAdobe PDFView/Open
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07_chapter 2.pdf1.31 MBAdobe PDFView/Open
08_chapter 3.pdf419.84 kBAdobe PDFView/Open
09_chapter 4.pdf1.22 MBAdobe PDFView/Open
11_bibliography.pdf324.8 kBAdobe PDFView/Open
12_list of publications.pdf2.85 MBAdobe PDFView/Open
13_abstract.pdf65.61 kBAdobe PDFView/Open
80_recommendation.pdf147.35 kBAdobe PDFView/Open
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