Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors

A mounting public health concern over mosquito-borne diseases, a global economic burden, and failure of current control measures due to escalating development of insecticides resistance have intensified the search for alternative ecofriendlier vector control strategies. An investigation was condu...

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Main Author: Ho, Lai Yee
Format: Thesis
Language:English
Published: 2021
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Online Access:http://eprints.usm.my/51919/1/HO%20LAI%20YEE.pdf
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spelling my-usm-ep.519192022-03-14T03:17:22Z Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors 2021-03 Ho, Lai Yee QH1-278.5 Natural history (General) A mounting public health concern over mosquito-borne diseases, a global economic burden, and failure of current control measures due to escalating development of insecticides resistance have intensified the search for alternative ecofriendlier vector control strategies. An investigation was conducted to explore the toxicity profiles of indigenous B. thuringiensis isolates from an ex-tin mining area. Verification was performed through microscopic identification and biochemical characterisations. Morphological features of the crystal proteins were assessed using scanning and transmission electron microscopy. Distribution of insecticidal genes and crystal protein classes were examined through PCR and SDS-PAGE analyses. Eventually, these isolates were screened for larvicidal and sublethal efficacies against laboratory strains of Ae. albopictus and Ae. aegypti. From the seven sampling sites, 13 B. thuringiensis isolates were obtained (A10C, D10D, N6Bss, 6a3s, 8a3, 8a3s, 8b3, R1, R2, R3, D1C, A2B and C6D) with an overall B. thuringiensis index of 0.07. Spherical-shaped crystal proteins were present in all isolates, while lesser numbers of ovoidal- and cuboidal-shaped crystal proteins were noted. Protein profiles revealed presence of eight classes of crystal proteins (Cry2, Cry4C/4D, Cry6A, Cry10, Cry11, Cry34, Cry35, Cyt1/2). Four of the isolates (N6Bss, 8a3, R1 and A2B) harboured all six of the examined insecticidal genes (cry1, cry2, cry4, cry10, cry11 and cyt2), which are known to produce Dipteran-specific delta-endotoxins. 2021-03 Thesis http://eprints.usm.my/51919/ http://eprints.usm.my/51919/1/HO%20LAI%20YEE.pdf application/pdf en public phd doctoral Perpustakaan Hamzah Sendut Pusat Pengajian Sains Kajihayat
institution Universiti Sains Malaysia
collection USM Institutional Repository
language English
topic QH1-278.5 Natural history (General)
spellingShingle QH1-278.5 Natural history (General)
Ho, Lai Yee
Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
description A mounting public health concern over mosquito-borne diseases, a global economic burden, and failure of current control measures due to escalating development of insecticides resistance have intensified the search for alternative ecofriendlier vector control strategies. An investigation was conducted to explore the toxicity profiles of indigenous B. thuringiensis isolates from an ex-tin mining area. Verification was performed through microscopic identification and biochemical characterisations. Morphological features of the crystal proteins were assessed using scanning and transmission electron microscopy. Distribution of insecticidal genes and crystal protein classes were examined through PCR and SDS-PAGE analyses. Eventually, these isolates were screened for larvicidal and sublethal efficacies against laboratory strains of Ae. albopictus and Ae. aegypti. From the seven sampling sites, 13 B. thuringiensis isolates were obtained (A10C, D10D, N6Bss, 6a3s, 8a3, 8a3s, 8b3, R1, R2, R3, D1C, A2B and C6D) with an overall B. thuringiensis index of 0.07. Spherical-shaped crystal proteins were present in all isolates, while lesser numbers of ovoidal- and cuboidal-shaped crystal proteins were noted. Protein profiles revealed presence of eight classes of crystal proteins (Cry2, Cry4C/4D, Cry6A, Cry10, Cry11, Cry34, Cry35, Cyt1/2). Four of the isolates (N6Bss, 8a3, R1 and A2B) harboured all six of the examined insecticidal genes (cry1, cry2, cry4, cry10, cry11 and cyt2), which are known to produce Dipteran-specific delta-endotoxins.
format Thesis
qualification_name Doctor of Philosophy (PhD.)
qualification_level Doctorate
author Ho, Lai Yee
author_facet Ho, Lai Yee
author_sort Ho, Lai Yee
title Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
title_short Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
title_full Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
title_fullStr Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
title_full_unstemmed Isolation, Characterisation And Bioefficacy Analysis Of Bacillus Thuringiensis (Bt) Strains Against Dengue Vectors
title_sort isolation, characterisation and bioefficacy analysis of bacillus thuringiensis (bt) strains against dengue vectors
granting_institution Perpustakaan Hamzah Sendut
granting_department Pusat Pengajian Sains Kajihayat
publishDate 2021
url http://eprints.usm.my/51919/1/HO%20LAI%20YEE.pdf
_version_ 1747822113706737664