The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal

The factors influencing the ability of Vibrio cholerae AC-V99 El Tor 01 Ogawa to tolerate acid killing after a pre-exposure to sub-lethal acid pH were studied. The effect of pre-exposure to sub-lethal acid pH on tolerance to other stresse s (cross-protection) including heat, osmotic and oxidative st...

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Main Author:	Zainal, Anneeza Zaity
Format:	Thesis
Language:	English
Published:	2007
Subjects:	QR Microbiology
Online Access:	https://ir.uitm.edu.my/id/eprint/27053/1/TM_ANNEEZA%20ZAITY%20ZAINAL%20AS%2007_5.pdf
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spelling	my-uitm-ir.270532020-01-06T02:26:16Z The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal 2007 Zainal, Anneeza Zaity QR Microbiology The factors influencing the ability of Vibrio cholerae AC-V99 El Tor 01 Ogawa to tolerate acid killing after a pre-exposure to sub-lethal acid pH were studied. The effect of pre-exposure to sub-lethal acid pH on tolerance to other stresse s (cross-protection) including heat, osmotic and oxidative stresses was also investigated. The involvement of de novo proteins synthesis and effect on cell morphology were also determined . Acid sensitivity test showed that the sublethal pHs for this strain ranged from pH 5.0 to pH 6.0 and at pH 4.5 and below the cells are completely killed. The ability of this bacterium to induce acid tolerance was tested by pre-exposing early exponential cells in LB + 3% NaCl at pH 5.0 for one hour before challenging them to pHs 3.5, 3.0 and 2.5 for a further one hour. Viable counts were determined by plating dilutions of the samples on LB + 3% agar (pH 7.0) at various intervals of time. Cells that were pre-exposed to pH 5.0 survived significantly better (P < 0.05) at these lethal pHs compared to those that were pre-exposed to pH 7.0. This response is partly dependent on de novo protein synthesis as treatment with chloramphenicol, a protein synthesis inhibitor during pre-exposure did not completely eliminate the respon se. Microscopic examination showed that acid induced cells were found to be elongated and segmented probably due to arrested cell division. The induct ion of acid tolerance response was found to be affected by growth phase, pH, temperature, pre-exposure time and initial cell density. Early exponential phase cells pre-exposed to pH 5.0 were found to have highest survival rate after one hour of challenge at pH 3.5 followed by stationary phase, late exponential phase and mid-exponential phase cells under the same conditions. A preexposure at pH 5.0 for three hours gave maximal protection against acid killing compared to one, two and three hours of pre-exposure time… 2007 Thesis https://ir.uitm.edu.my/id/eprint/27053/ https://ir.uitm.edu.my/id/eprint/27053/1/TM_ANNEEZA%20ZAITY%20ZAINAL%20AS%2007_5.pdf text en public masters Universiti Teknologi Mara Faculty of Applied Sciences
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
topic	QR Microbiology
spellingShingle	QR Microbiology Zainal, Anneeza Zaity The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
description	The factors influencing the ability of Vibrio cholerae AC-V99 El Tor 01 Ogawa to tolerate acid killing after a pre-exposure to sub-lethal acid pH were studied. The effect of pre-exposure to sub-lethal acid pH on tolerance to other stresse s (cross-protection) including heat, osmotic and oxidative stresses was also investigated. The involvement of de novo proteins synthesis and effect on cell morphology were also determined . Acid sensitivity test showed that the sublethal pHs for this strain ranged from pH 5.0 to pH 6.0 and at pH 4.5 and below the cells are completely killed. The ability of this bacterium to induce acid tolerance was tested by pre-exposing early exponential cells in LB + 3% NaCl at pH 5.0 for one hour before challenging them to pHs 3.5, 3.0 and 2.5 for a further one hour. Viable counts were determined by plating dilutions of the samples on LB + 3% agar (pH 7.0) at various intervals of time. Cells that were pre-exposed to pH 5.0 survived significantly better (P < 0.05) at these lethal pHs compared to those that were pre-exposed to pH 7.0. This response is partly dependent on de novo protein synthesis as treatment with chloramphenicol, a protein synthesis inhibitor during pre-exposure did not completely eliminate the respon se. Microscopic examination showed that acid induced cells were found to be elongated and segmented probably due to arrested cell division. The induct ion of acid tolerance response was found to be affected by growth phase, pH, temperature, pre-exposure time and initial cell density. Early exponential phase cells pre-exposed to pH 5.0 were found to have highest survival rate after one hour of challenge at pH 3.5 followed by stationary phase, late exponential phase and mid-exponential phase cells under the same conditions. A preexposure at pH 5.0 for three hours gave maximal protection against acid killing compared to one, two and three hours of pre-exposure time…
format	Thesis
qualification_level	Master's degree
author	Zainal, Anneeza Zaity
author_facet	Zainal, Anneeza Zaity
author_sort	Zainal, Anneeza Zaity
title	The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
title_short	The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
title_full	The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
title_fullStr	The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
title_full_unstemmed	The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal
title_sort	induction of acid tolerance in vibrio cholerae - factors influencing and cross-protection responses / anneeza zaity zainal
granting_institution	Universiti Teknologi Mara
granting_department	Faculty of Applied Sciences
publishDate	2007
url	https://ir.uitm.edu.my/id/eprint/27053/1/TM_ANNEEZA%20ZAITY%20ZAINAL%20AS%2007_5.pdf
_version_	1783733921769324544

The induction of acid tolerance in Vibrio cholerae - factors influencing and cross-protection responses / Anneeza Zaity Zainal

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