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Proposal for a method to estimate nutrient shock effects in bacteria

Proposal for a method to estimate nutrient shock effects in bacteria
Proposal for a method to estimate nutrient shock effects in bacteria
Plating methods are still the golden standard in microbiology; however, some studies have shown that these techniques can underestimate the microbial concentrations and diversity. A nutrient shock is one of the mechanisms proposed to explain this phenomenon. In this study, a tentative method to assess nutrient shock effects was tested. Findings To estimate the extent of nutrient shock effects, two strains isolated from tap water (Sphingomonas capsulata and Methylobacterium sp.) and two culture collection strains (E. coli CECT 434 and Pseudomonas fluorescens ATCC 13525) were exposed both to low and high nutrient conditions for different times and then placed in low nutrient medium (R2A) and rich nutrient medium (TSA). The average improvement (A.I.) of recovery between R2A and TSA for the different times was calculated to more simply assess the difference obtained in culturability between each medium. As expected, A.I. was higher when cells were plated after the exposition to water than when they were recovered from high-nutrient medium showing the existence of a nutrient shock for the diverse bacteria used. S. capsulata was the species most affected by this phenomenon.

This work provides a method to consistently determine the extent of nutrient shock effects on different microorganisms and hence quantify the ability of each species to deal with sudden increases in substrate concentration.
1756-0500
422
Azevedo, Nuno F.
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Bragança, Sofia M.
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Simões, Lúcia C.
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Cerqueira, Laura
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Almeida, Carina
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Keevil, Charles W.
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
Vieira, Maria J.
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Azevedo, Nuno F.
24c4eb52-0c98-443b-881f-7a1449c9ac26
Bragança, Sofia M.
7df84b21-9316-4ee2-9445-4746df073fd8
Simões, Lúcia C.
1b74778b-c1c3-4163-935c-e3e688751e2e
Cerqueira, Laura
61343b41-4742-4057-94e9-2ef4ea145613
Almeida, Carina
08bcd2c4-bb43-482c-a3ed-517f5d1b9abf
Keevil, Charles W.
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
Vieira, Maria J.
d972e877-d85b-488c-8b0f-358f79d2fa29

Azevedo, Nuno F., Bragança, Sofia M., Simões, Lúcia C., Cerqueira, Laura, Almeida, Carina, Keevil, Charles W. and Vieira, Maria J. (2012) Proposal for a method to estimate nutrient shock effects in bacteria. BMC Research Notes, 5 (1), 422. (doi:10.1186/1756-0500-5-422).

Record type: Article

Abstract

Plating methods are still the golden standard in microbiology; however, some studies have shown that these techniques can underestimate the microbial concentrations and diversity. A nutrient shock is one of the mechanisms proposed to explain this phenomenon. In this study, a tentative method to assess nutrient shock effects was tested. Findings To estimate the extent of nutrient shock effects, two strains isolated from tap water (Sphingomonas capsulata and Methylobacterium sp.) and two culture collection strains (E. coli CECT 434 and Pseudomonas fluorescens ATCC 13525) were exposed both to low and high nutrient conditions for different times and then placed in low nutrient medium (R2A) and rich nutrient medium (TSA). The average improvement (A.I.) of recovery between R2A and TSA for the different times was calculated to more simply assess the difference obtained in culturability between each medium. As expected, A.I. was higher when cells were plated after the exposition to water than when they were recovered from high-nutrient medium showing the existence of a nutrient shock for the diverse bacteria used. S. capsulata was the species most affected by this phenomenon.

This work provides a method to consistently determine the extent of nutrient shock effects on different microorganisms and hence quantify the ability of each species to deal with sudden increases in substrate concentration.

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Published date: 8 August 2012
Organisations: Centre for Biological Sciences

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Local EPrints ID: 342188
URI: https://eprints.soton.ac.uk/id/eprint/342188
ISSN: 1756-0500
PURE UUID: 5c8708e5-765b-4b14-a6bd-fbc97417a2a6
ORCID for Charles W. Keevil: ORCID iD orcid.org/0000-0003-1917-7706

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Date deposited: 14 Aug 2012 15:57
Last modified: 29 Oct 2019 01:54

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Contributors

Author: Nuno F. Azevedo
Author: Sofia M. Bragança
Author: Lúcia C. Simões
Author: Laura Cerqueira
Author: Carina Almeida
Author: Maria J. Vieira

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