Viable but Not Cultivable Bacteria

Colwell, Rita R.

doi:10.1007/978-3-540-85465-4_1

Cited by 35 publications

(31 citation statements)

References 43 publications

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“…Bacteria have evolved a wide array of adaptive responses that allow them to survive when conditions are not conducive to active growth. From the many strategies, such as sporulation, one such response is their ability to enter a dormant state where they remain viable but are no longer culturable (Colwell, ; Oliver, ). We found that Δ toxS becomes non‐culturable at an equivalent rate as Δ toxR when the cultures are grown under alkaline pH.…”

Section: Discussionmentioning

confidence: 99%

Role of ToxS in the proteolytic cascade of virulence regulator ToxR in Vibrio cholerae

Almagro‐Moreno

Root

Taylor

2015

Molecular Microbiology

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SummaryTwo of the primary virulence regulators of Vibrio cholerae, ToxR and TcpP, function together with cognate effector proteins. ToxR undergoes regulated intramembrane proteolysis (RIP) during late stationary phase in response to nutrient limitation at alkaline pH; however, the specific function of its cognate ToxS remains unresolved. In this work, we found that ToxR rapidly becomes undetectable in a ΔtoxS mutant when cultures are exposed to either starvation conditions or after alkaline pH shock individually. A ΔtoxS mutant enters into a dormant state associated with the proteolysis of ToxR at a faster rate than wild-type, closely resembling a ΔtoxR mutant. Using a mutant with a periplasmic substitution in ToxS, we found that the proteases DegS and DegP function additively with VesC and a novel protease, TapA, to degrade ToxR in the mutant. Overall, the results shown here reveal a role for ToxS in the stabilization of ToxR by protecting the virulence regulator from premature proteolysis.

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Section: Discussionmentioning

confidence: 99%

Role of ToxS in the proteolytic cascade of virulence regulator ToxR in Vibrio cholerae

Almagro‐Moreno

Root

Taylor

2015

Molecular Microbiology

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“…Hence, as a simplifying assumption, we could assume that the active pool experiences a negligible rate of death, and that each individual becomes metabolically inactive before dying. While this may be difficult for traditional biogeographers to accept, and while active microorganisms are likely to experience death from predation and lysis, the distinction between death and dormancy has been a source of argument in microbiology for decades (Roszak & Colwell, 1987; Colwell, 2009). In fact, natural microbial death probably ensues after the exhaustion of endogenous resources in dormant states (Colwell, 2000).…”

Section: Incorporating Dormancy Into Unified Neutral Theorymentioning

confidence: 99%

“…Dormancy, as a general property of microorganisms (Postgate, 2000), has become a central interest in microbial ecology (Roszak & Colwell, 1987; Prosser et al. , 2007; Colwell, 2009), and it has been suggested that dormancy is the single most important fitness trait explaining the distribution and persistence of bacteria in aquatic systems (Stevenson, 1978). Because dormancy has proven to be important to the study of microbial ecology, it is likely that dormancy has important influences on microbial biogeography and should be explicitly included in its development.…”

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confidence: 99%

Synthesizing traditional biogeography with microbial ecology: the importance of dormancy

Locey¹

2010

Journal of Biogeography

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The discovery of biogeographical patterns among microbial communities has led to a focus on the empirical evaluation of the importance of dispersal limitation in microbial biota. As a result, the spatial distribution of microbial diversity has been increasingly studied while the synthesis of biogeographical theory with microbial ecology remains undeveloped. To make biogeographical theory relevant to microbial ecology, microbial traits that potentially affect the distribution of microbial diversity need to be considered. Given that many microorganisms in natural environments are in a state of dormancy and that dormancy is an important microbial fitness trait, I provide a first attempt to account for the effects of dormancy on microbial biogeography by treating dormancy as a fundamental biogeographical response. I discuss the effects of dormancy on the equilibrium theory of island biogeography and on the unified neutral theory of biodiversity and biogeography, and suggest how the equilibrium theory of island biogeography can produce predictions approaching those of the Baas‐Becking hypothesis (i.e. everything is everywhere, but the environment selects). In addition, I present a conceptual model of the unified neutral theory of biodiversity and biogeography, generalized to account for dormancy, from which a full model can be constructed for species with or without dormant life history stages.

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“…Similar to grazing and/or predation of microorganisms, the predation pressures in different aquatic environments are difficult to predict. The prediction of actual number of microorganisms became more complicated with recent findings on the occurrence of VBNC cells in stressed environments (Colwell, 2009;Oliver, 2010).…”

Section: Current Microbial Water Quality Modelsmentioning

confidence: 99%

“…Conventional laboratory methods often rely on the ability of a cell to grow on appropriate nutrient media. However, there is strong evidence to show that in certain circumstances, a cell is able to maintain its metabolic activity and membrane integrity although no growth has been observed in the appropriate nutrient media (Lleo et al, 1998;Colwell, 2009). There are also strong debates on whether a VBNC state is a survival physiological state or the transition state towards the death phase (Kell et al, 1998;Bogosian and Bourneuf, 2001)?…”

Section: Summary Of Literature Reviewmentioning

confidence: 99%

Molecular detection and analysis of enterococcus faecalis survival in tropical environmental waters

Goh¹

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and especially Aidil Bin Md Idris for their kind assistance and guidance in the laboratory and administration matters. Special thank is also dedicated to Ng Soo Ching from graduate study office for her kind help in all the administration matters. To those whom I have not mentioned and helped me directly or indirectly in my research, I am deeply grateful. My greatest thank to my family members for their love, encouragement and unconditional support. My deepest gratitude to my husband who has gone through the ups and downs of my research with me. To my family, I dedicate this thesis! iii

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Viable but Not Cultivable Bacteria

Cited by 35 publications

References 43 publications

Role of ToxS in the proteolytic cascade of virulence regulator ToxR in Vibrio cholerae

Role of ToxS in the proteolytic cascade of virulence regulator ToxR in Vibrio cholerae

Synthesizing traditional biogeography with microbial ecology: the importance of dormancy

Molecular detection and analysis of enterococcus faecalis survival in tropical environmental waters

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