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Diversity analysis and functional role of insect gut bacteria

Shodhganga@INFLIBNET

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Title Diversity analysis and functional role of insect gut bacteria
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Contributor Raman, Rajagopal
 
Subject Zoology
Insect
Bacteria
 
Description In this report, the community structure of gut bacteria and their functional role in two different
newlineinsects Helicoverpa armigera and Drosophila melanogaster were studied. H. armigera is an
newlineimportant crop pest with increased resistance to major groups of pesticides while D.
newlinemelanogaster is an experimental model system in biology. In the first study dealing with H.
newlinearmigera, bacterial members of genus Bacillus, Paenibacillus, Cellulomonas, Acinetobacter,
newlineMicrococcus, Enterobacter, and Enterococcus were isolated and identified. The culture
newlineindependent molecular analysis also identified the presence of other bacterial candidates. TRFLP
newlineanalysis revealed that the bacterial community of this insect is dependent on the host plant
newlineon which it feeds. The strong similarity of the Acinetobacter, in the gut, to bacteria isolated from
newlinexenobiotic degrading ecosystems suggested its putative role in metabolizing insecticides.
newlineAcinetobacter not only was able to grow in the presence of quinalphos but was also able to
newlinedegrade it efficiently. When grown in the presence of quinalphos, the esterase enzyme levels of
newlinethis bacterial candidate increased significantly. Insects reared on Acinetobacter, displayed higher
newlineesterase levels and low susceptibility to quinalphos while the axenic insects succumbed to the
newlinetoxicity of quinalphos.
newlineBacterial members of genus Enterobacter, Pantoea and Enterococcus were isolated and
newlineidentified from D. melanogaster midgut. Culturable method divulged differences in the bacterial
newlineflora between lab reared and wild collected males and females. An effort was made to understand
newlinethe roles played by this resident gut microflora in shaping the development of an insect by
newlinegrowing Drosophila melanogaster flies in Caltech half diet (HD). It was found that in the
newlineabsence of microbes, the D. melanogaster flies raised in HD medium show delayed and lower
newlinepupation, eclosion, fecundity and feeding rates, along with a decrease in size of larvae, pupae
newlineand adults than their non-sterile HD
References 138-148 Summary 149-151
 
Date 2014-04-28T11:39:45Z
2014-04-28T11:39:45Z
2014-04-28
n.d.
2012
n.d.
 
Type Ph.D.
 
Identifier http://hdl.handle.net/10603/18009
 
Language English US
 
Relation -
 
Rights university
 
Format 151p.
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None
 
Coverage Zoology
 
Publisher New Delhi
University of Delhi
Dept. of Zoology
 
Source INFLIBNET