Remembering Malcolm J. Casadaban

doi:10.1128/jb.00484-10

Cited by 5 publications

(2 citation statements)

References 46 publications

(40 reference statements)

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“…AJW678 is lacking the IS element [42] in the flhD promoter that makes bacteria highly motile. MC1000 is another K-12 strain [58,59]. It contains an IS5 in the flhD promoter [47], is highly motile, but produces much reduced biofilm amounts.…”

Section: Methodsmentioning

confidence: 99%

OmpR and RcsB abolish temporal and spatial changes in expression of flhD in Escherichia coli Biofilm

et al. 2013

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BackgroundBiofilms are communities of bacteria that are characterized by specific phenotypes, including an increased resistance towards anti-microbials and the host immune system. This calls for the development of novel biofilm prevention and treatment options to combat infectious disease. In Escherichia coli, numerous global regulators have been implicated in the control of biofilm associated cell surface organelles. These include the flagellar regulator FlhD/FlhC, the osmoregulator EnvZ/OmpR, and the colanic acid activator RcsCDB. Using flow cell technology and fluorescence microscopy, we determined the temporal expression from flhD::gfp, ompR::gfp, and rcsB::gfp in E. coli biofilm, as well as the impact of the negative regulation of flhD by OmpR and RcsB. Spatial gene expression was investigated from flhD::gfp.ResultsThe temporal gene expression profile for flhD yielded an early peak at 12 h, a minimum of expression at 35 h, and a second increase in expression towards 51 h of biofilm development. In contrast, the ompR profile showed a peak at 35 h. A mutation in ompR abolished time dependence of flhD expression after the initial growth period of 12 h. Intriguingly, rcsB expression did not correlate inversely with flhD expression, yet a mutation in rcsB abolished time dependence of flhD expression as well. Spatially, expression of flhD was highest in the outermost layer of the biofilm in the parent strain. In ompR and rcsB mutants, flhD was expressed throughout the biofilm. Mutations in both, ompR and rcsB increased flhD expression throughout all temporal and spatial experiments. This increase was paralleled by reductions in biofilm amounts at four tested time points.ConclusionOur data lead to the conclusion that FlhD/FlhC and its regulation by OmpR and RcsB may be our first target mechanism for the development of novel biofilm prevention and treatment techniques.

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Section: Methodsmentioning

confidence: 99%

OmpR and RcsB abolish temporal and spatial changes in expression of flhD in Escherichia coli Biofilm

et al. 2013

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“…There are many E. coli K-12 derivatives currently used in research and production laboratories worldwide, including MC4100, engineered by Malcolm Casadaban (2). Of the 801 completely sequenced E.…”

Section: Announcementmentioning

confidence: 99%

Complete Genome Sequence of Escherichia coli BE104, an MC4100 Derivative Lacking the Methionine Reductive Pathway

Anton

Morgan

Ezraty

et al. 2019

Microbiol Resour Announc

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Laboratory-acquired lethal infections by potential bioweapons pathogens including Ebola in 2014

Silver¹

2015

FEMS Microbiology Letters

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Researchers studying both cellular and viral disease agents in the laboratory have become infected since the early days of microbiology 150 years ago. However, in the early 21st century, new concerns about bioweapons being used to generate terror and also with a series of newly emerging or newly understood disease-causing microbes have resulted in infections and deaths of workers studying these microbes in the laboratory, generally to gain understanding and to develop treatments and vaccines. Here, five examples are summarized: (i) smallpox virus escaped from a UK laboratory where it was being maintained and stored, (ii) the 2014 infections and deaths of five researchers who were isolating West African Ebola virus for DNA sequencing epidemiology studies, (iii) and (iv) two recent infections that happened in the same US laboratory where researchers were infected with agents causing septicemic Yersinia plague and Bacillus anthrax and (v) the 2012 death in California from laboratory infection by Neisseria meningitidis resulting in spinal meningitis.

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Remembering Malcolm J. Casadaban

Cited by 5 publications

References 46 publications

OmpR and RcsB abolish temporal and spatial changes in expression of flhD in Escherichia coli Biofilm

OmpR and RcsB abolish temporal and spatial changes in expression of flhD in Escherichia coli Biofilm

Complete Genome Sequence of Escherichia coli BE104, an MC4100 Derivative Lacking the Methionine Reductive Pathway

Laboratory-acquired lethal infections by potential bioweapons pathogens including Ebola in 2014

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