Bacterial evolution in simple microcosms

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Citations (Scopus)

Abstract

Microcosms have been used extensively to investigate ecological factors, evolutionary dynamics and the underlying molecular biology of adapting populations of bacteria in experimental evolution studies. One such experimental system has combined simple glass vials containing King’s B liquid growth medium with the model soil and plant-associated pseudomonad, Pseudomonas fluorescens SBW25. In these, evolution reproducibly generates the Wrinkly Spreader genotype, a novel class of adaptive mutations that enable Pf. SBW25 to produce a robust, physical cohesive–class biofilm at the air-liquid interface. The analysis of Wrinkly Spreader mini-Tn5 mutants led to the identification of cellulose as the main matrix component of the biofilm, and ultimately to the discovery of the mutation in a chemosensory-like system that activated the Wrinkly Spreader phenotype through the over-production of cyclic-di-GMP. Parallel ecological investigations have shown the importance of O2 availability for the evolution and success of the Wrinkly Spreader. The initial colonisers establish an O2 gradient, dividing the microcosm into a 100 – 200 µm high-O2 zone at the air-liquid interface, and second, deeper low-O2 zone in the rest of the liquid column. Growth is O2–limited in King’s B medium, and it is the domination of the air-liquid interface that guarantees access to O2 and underlies the fitness advantage the Wrinkly Spreader has over non-biofilm–forming competitors including the ancestral wild-type Pf. SBW25. However, recent experiments demonstrate that Wrinkly Spreader fitness is reduced in static microcosms containing lower levels of nutrients, or in those in which King’s B liquid viscosity has been increased. These findings demonstrate that the Wrinkly Spreader biofilm is a finely-balanced solution to the colonisation of the air-liquid interface in static microcosms, and changing environmental conditions will impact directly on Wrinkly Spreader fitness. This work highlights the importance of environmental factors, which along with competition, help guide the evolution of Pf. SBW25 in simple microcosms, invariably leading to the rise of the Wrinkly Spreaders.
Original languageEnglish
Title of host publicationMicrocosms
Subtitle of host publicationecology, biological implications and environmental impact
EditorsChristopher C. Harris
Place of PublicationHauppauge, NY
PublisherNova Publishers
ISBN (Electronic)9781626186620
ISBN (Print)9781626186613
Publication statusPublished - 2013

Publication series

NameMicrobiology Research Advances
PublisherNova Publishers

Fingerprint

microcosm
liquid
biofilm
fitness
air
mutation
phenotype
cellulose
genotype
environmental factor
colonization
viscosity
glass
environmental conditions
bacterium
matrix
nutrient
soil
experiment

Cite this

Spiers, A. J. (2013). Bacterial evolution in simple microcosms. In C. C. Harris (Ed.), Microcosms: ecology, biological implications and environmental impact (Microbiology Research Advances). Hauppauge, NY : Nova Publishers.
Spiers, Andrew J. / Bacterial evolution in simple microcosms. Microcosms: ecology, biological implications and environmental impact. editor / Christopher C. Harris. Hauppauge, NY : Nova Publishers, 2013. (Microbiology Research Advances).
@inbook{4c57c4dee413433584e8ba70be4fac15,
title = "Bacterial evolution in simple microcosms",
abstract = "Microcosms have been used extensively to investigate ecological factors, evolutionary dynamics and the underlying molecular biology of adapting populations of bacteria in experimental evolution studies. One such experimental system has combined simple glass vials containing King’s B liquid growth medium with the model soil and plant-associated pseudomonad, Pseudomonas fluorescens SBW25. In these, evolution reproducibly generates the Wrinkly Spreader genotype, a novel class of adaptive mutations that enable Pf. SBW25 to produce a robust, physical cohesive–class biofilm at the air-liquid interface. The analysis of Wrinkly Spreader mini-Tn5 mutants led to the identification of cellulose as the main matrix component of the biofilm, and ultimately to the discovery of the mutation in a chemosensory-like system that activated the Wrinkly Spreader phenotype through the over-production of cyclic-di-GMP. Parallel ecological investigations have shown the importance of O2 availability for the evolution and success of the Wrinkly Spreader. The initial colonisers establish an O2 gradient, dividing the microcosm into a 100 – 200 µm high-O2 zone at the air-liquid interface, and second, deeper low-O2 zone in the rest of the liquid column. Growth is O2–limited in King’s B medium, and it is the domination of the air-liquid interface that guarantees access to O2 and underlies the fitness advantage the Wrinkly Spreader has over non-biofilm–forming competitors including the ancestral wild-type Pf. SBW25. However, recent experiments demonstrate that Wrinkly Spreader fitness is reduced in static microcosms containing lower levels of nutrients, or in those in which King’s B liquid viscosity has been increased. These findings demonstrate that the Wrinkly Spreader biofilm is a finely-balanced solution to the colonisation of the air-liquid interface in static microcosms, and changing environmental conditions will impact directly on Wrinkly Spreader fitness. This work highlights the importance of environmental factors, which along with competition, help guide the evolution of Pf. SBW25 in simple microcosms, invariably leading to the rise of the Wrinkly Spreaders.",
author = "Spiers, {Andrew J.}",
year = "2013",
language = "English",
isbn = "9781626186613",
series = "Microbiology Research Advances",
publisher = "Nova Publishers",
editor = "Harris, {Christopher C.}",
booktitle = "Microcosms",

}

Spiers, AJ 2013, Bacterial evolution in simple microcosms. in CC Harris (ed.), Microcosms: ecology, biological implications and environmental impact. Microbiology Research Advances, Nova Publishers, Hauppauge, NY .

Bacterial evolution in simple microcosms. / Spiers, Andrew J.

Microcosms: ecology, biological implications and environmental impact. ed. / Christopher C. Harris. Hauppauge, NY : Nova Publishers, 2013. (Microbiology Research Advances).

Research output: Chapter in Book/Report/Conference proceedingChapter

TY - CHAP

T1 - Bacterial evolution in simple microcosms

AU - Spiers, Andrew J.

PY - 2013

Y1 - 2013

N2 - Microcosms have been used extensively to investigate ecological factors, evolutionary dynamics and the underlying molecular biology of adapting populations of bacteria in experimental evolution studies. One such experimental system has combined simple glass vials containing King’s B liquid growth medium with the model soil and plant-associated pseudomonad, Pseudomonas fluorescens SBW25. In these, evolution reproducibly generates the Wrinkly Spreader genotype, a novel class of adaptive mutations that enable Pf. SBW25 to produce a robust, physical cohesive–class biofilm at the air-liquid interface. The analysis of Wrinkly Spreader mini-Tn5 mutants led to the identification of cellulose as the main matrix component of the biofilm, and ultimately to the discovery of the mutation in a chemosensory-like system that activated the Wrinkly Spreader phenotype through the over-production of cyclic-di-GMP. Parallel ecological investigations have shown the importance of O2 availability for the evolution and success of the Wrinkly Spreader. The initial colonisers establish an O2 gradient, dividing the microcosm into a 100 – 200 µm high-O2 zone at the air-liquid interface, and second, deeper low-O2 zone in the rest of the liquid column. Growth is O2–limited in King’s B medium, and it is the domination of the air-liquid interface that guarantees access to O2 and underlies the fitness advantage the Wrinkly Spreader has over non-biofilm–forming competitors including the ancestral wild-type Pf. SBW25. However, recent experiments demonstrate that Wrinkly Spreader fitness is reduced in static microcosms containing lower levels of nutrients, or in those in which King’s B liquid viscosity has been increased. These findings demonstrate that the Wrinkly Spreader biofilm is a finely-balanced solution to the colonisation of the air-liquid interface in static microcosms, and changing environmental conditions will impact directly on Wrinkly Spreader fitness. This work highlights the importance of environmental factors, which along with competition, help guide the evolution of Pf. SBW25 in simple microcosms, invariably leading to the rise of the Wrinkly Spreaders.

AB - Microcosms have been used extensively to investigate ecological factors, evolutionary dynamics and the underlying molecular biology of adapting populations of bacteria in experimental evolution studies. One such experimental system has combined simple glass vials containing King’s B liquid growth medium with the model soil and plant-associated pseudomonad, Pseudomonas fluorescens SBW25. In these, evolution reproducibly generates the Wrinkly Spreader genotype, a novel class of adaptive mutations that enable Pf. SBW25 to produce a robust, physical cohesive–class biofilm at the air-liquid interface. The analysis of Wrinkly Spreader mini-Tn5 mutants led to the identification of cellulose as the main matrix component of the biofilm, and ultimately to the discovery of the mutation in a chemosensory-like system that activated the Wrinkly Spreader phenotype through the over-production of cyclic-di-GMP. Parallel ecological investigations have shown the importance of O2 availability for the evolution and success of the Wrinkly Spreader. The initial colonisers establish an O2 gradient, dividing the microcosm into a 100 – 200 µm high-O2 zone at the air-liquid interface, and second, deeper low-O2 zone in the rest of the liquid column. Growth is O2–limited in King’s B medium, and it is the domination of the air-liquid interface that guarantees access to O2 and underlies the fitness advantage the Wrinkly Spreader has over non-biofilm–forming competitors including the ancestral wild-type Pf. SBW25. However, recent experiments demonstrate that Wrinkly Spreader fitness is reduced in static microcosms containing lower levels of nutrients, or in those in which King’s B liquid viscosity has been increased. These findings demonstrate that the Wrinkly Spreader biofilm is a finely-balanced solution to the colonisation of the air-liquid interface in static microcosms, and changing environmental conditions will impact directly on Wrinkly Spreader fitness. This work highlights the importance of environmental factors, which along with competition, help guide the evolution of Pf. SBW25 in simple microcosms, invariably leading to the rise of the Wrinkly Spreaders.

M3 - Chapter

SN - 9781626186613

T3 - Microbiology Research Advances

BT - Microcosms

A2 - Harris, Christopher C.

PB - Nova Publishers

CY - Hauppauge, NY

ER -

Spiers AJ. Bacterial evolution in simple microcosms. In Harris CC, editor, Microcosms: ecology, biological implications and environmental impact. Hauppauge, NY : Nova Publishers. 2013. (Microbiology Research Advances).