scholarly journals BldD-based bimolecular fluorescence complementation for in vivo detection of the second messenger cyclic di-GMP

2021 ◽  
Author(s):  
Manuel Halte ◽  
Mirka E. Wörmann ◽  
Maxim Bogisch ◽  
Marc Erhardt ◽  
Natalia Tschowri
Keyword(s):  
Escherichia Coli ◽  
Single Cell ◽  
Salmonella Enterica ◽  
Second Messenger ◽  
Bimolecular Fluorescence Complementation ◽  
Bacterial Physiology ◽  
Serovar Typhimurium ◽  
Fluorescence Complementation ◽  
Bimolecular Fluorescence

AbstractThe widespread bacterial second messenger bis-(3’-5’)-cyclic diguanosine monophosphate (c-di-GMP) is an important regulator of biofilm formation, virulence and cell differentiation. C-di-GMP-specific biosensors that allow detection and visualization of c-di-GMP levels in living cells are key to our understanding of how c-di-GMP fluctuations drive cellular responses. Here, we describe a novel c-di-GMP biosensor, CensYBL, that is based on c-di-GMP-induced dimerization of the effector protein BldD from Streptomyces resulting in bimolecular fluorescence complementation of split-YPet fusion proteins. As a proof-of-principle, we demonstrate that CensYBL is functional in detecting fluctuations in intracellular c-di-GMP levels in the Gram-negative model bacteria Escherichia coli and Salmonella enterica serovar Typhimurium. Using deletion mutants of c-di-GMP diguanylate cyclases and phosphodiesterases, we show that c-di-GMP dependent dimerization of CBldD-YPet results in fluorescence complementation reflecting intracellular c-di-GMP levels. Overall, we demonstrate that the CensYBL biosensor is a user-friendly and versatile tool that allows to investigate c-di-GMP variations using single-cell and population-wide experimental set-ups.ImportanceThe second messenger c-di-GMP controls various bacterial functions including development of resistant biofilm communities and transition into dormant spores. In vivo detection of c-di-GMP levels is therefore crucial for a better understanding of how intracellular c-di-GMP levels induce changes of bacterial physiology. Here, we describe the design of a novel c-di-GMP biosensor and demonstrate its effective application in investigating fluctuations in intracellular c-di-GMP levels in Escherichia coli and Salmonella enterica serovar Typhimurium on a population-based and single-cell level.

scholarly journals In Vivo Validation of Bimolecular Fluorescence Complementation (BiFC) to Investigate Aggregate Formation in Amyotrophic Lateral Sclerosis (ALS)

2020 ◽  
Author(s):  
Emily K Don ◽  
Alina Maschirow ◽  
Rowan A W Radford ◽  
Natalie M Scherer ◽  
Andres Vidal-Itriago ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Disease Onset ◽  
Bimolecular Fluorescence Complementation ◽  
Aggregate Formation ◽  
Reporter Protein ◽  
Fluorescent Reporter ◽  
Lateral Sclerosis ◽  
Fluorescence Complementation ◽  
Bimolecular Fluorescence

AbstractAmyotrophic lateral sclerosis (ALS) is a form of motor neuron disease (MND) that is characterized by the progressive loss of motor neurons within the spinal cord, brainstem and motor cortex. Although ALS clinically manifests as a heterogeneous disease, with varying disease onset and survival, a unifying feature is the presence of ubiquitinated cytoplasmic protein inclusion aggregates containing TDP-43. However, the precise mechanisms linking protein inclusions and aggregation to neuronal loss are currently poorly understood.Bimolecular Fluorescence Complementation (BiFC) takes advantage the association of fluorophore fragments (non-fluorescent on their own) that are attached to an aggregation prone protein of interest. Interaction of the proteins of interest allows for the fluorescent reporter protein to fold into its native state and emit a fluorescent signal. Here, we combined the power of BiFC with the advantages of the zebrafish system to validate, optimize and visualize of the formation of ALS-linked aggregates in real time in a vertebrate model. We further provide in vivo validation of the selectivity of this technique and demonstrate reduced spontaneous self-assembly of the non-fluorescent fragments in vivo by introducing a fluorophore mutation. Additionally, we report preliminary findings on the dynamic aggregation of the ALS-linked hallmark proteins Fus and TDP-43 in their corresponding nuclear and cytoplasmic compartments using BiFC.Overall, our data demonstrates the suitability of this BiFC approach to study and characterize ALS-linked aggregate formation in vivo. Importantly, the same principle can be applied in the context of other neurodegenerative diseases and has therefore critical implications to advance our understanding of pathologies that underlie aberrant protein aggregation.

scholarly journals Rcs and PhoPQ Regulatory Overlap in the Control of Salmonella enterica Virulence

2007 ◽  
Vol 189 (18) ◽  
pp. 6635-6644 ◽  
Author(s):  
Clara B. García-Calderón ◽  
Josep Casadesús ◽  
Francisco Ramos-Morales
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Salmonella Enterica ◽  
In Vivo Studies ◽  
Genetic Screens ◽  
Signal Transduction System ◽  
Constitutive Activation ◽  
Regulatory Systems ◽  
Serovar Typhimurium

ABSTRACT Genetic screens based on the use of MudJ-generated lac fusions permitted the identification of novel genes regulated by the Rcs signal transduction system in Salmonella enterica serovar Typhimurium. Besides genes that are also found in the Escherichia coli genome, our screens identified Salmonella-specific genes regulated by RcsB, including bapA, siiE, srfA, and srfB. Here we show that the srfABC operon is negatively regulated by RcsB and by PhoP. In vivo studies using mutants with constitutive activation of the Rcs and/or PhoPQ system suggested that there is an overlap between these regulatory systems in the control of Salmonella virulence.

scholarly journals Comparison of Escherichia coli surface attachment methods for single-cell microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yao-Kuan Wang ◽  
Ekaterina Krasnopeeva ◽  
Ssu-Yuan Lin ◽  
Fan Bai ◽  
Teuta Pilizota ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Single Cell ◽  
Super Resolution ◽  
Bacterial Cells ◽  
Surface Attachment ◽  
Bacterial Physiology ◽  
E Coli ◽  
Single Cell Imaging ◽  
Atomic Force

AbstractFor in vivo, single-cell imaging bacterial cells are commonly immobilised via physical confinement or surface attachment. Different surface attachment methods have been used both for atomic force and optical microscopy (including super resolution), and some have been reported to affect bacterial physiology. However, a systematic comparison of the effects these attachment methods have on the bacterial physiology is lacking. Here we present such a comparison for bacterium Escherichia coli, and assess the growth rate, size and intracellular pH of cells growing attached to different, commonly used, surfaces. We demonstrate that E. coli grow at the same rate, length and internal pH on all the tested surfaces when in the same growth medium. The result suggests that tested attachment methods can be used interchangeably when studying E. coli physiology.

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