scholarly journals Red Fluorescent Proteins for Gene Expression and Protein Localization Studies in Streptococcus pneumoniae and Efficient Transformation with DNA Assembled via the Gibson Assembly Method

2015 ◽  
Vol 81 (20) ◽  
pp. 7244-7252 ◽  
Author(s):  
Katrin Beilharz ◽  
Renske van Raaphorst ◽  
Morten Kjos ◽  
Jan-Willem Veening
Keyword(s):  
Gene Expression ◽  
Streptococcus Pneumoniae ◽  
Cell Biology ◽  
Fluorescent Proteins ◽  
Protein Localization ◽  
Gibson Assembly ◽  
Content Type ◽  
Assembly Method ◽  
Red Fluorescent Proteins ◽  
Wide Range

ABSTRACTDuring the last decades, a wide range of fluorescent proteins (FPs) have been developed and improved. This has had a great impact on the possibilities in biological imaging and the investigation of cellular processes at the single-cell level. Recently, we have benchmarked a set of green fluorescent proteins (GFPs) and generated a codon-optimized superfolder GFP for efficient use in the important human pathogenStreptococcus pneumoniaeand other low-GC Gram-positive bacteria. In the present work, we constructed and compared four red fluorescent proteins (RFPs) inS. pneumoniae. Two orange-red variants, mOrange2 and TagRFP, and two far-red FPs, mKate2 and mCherry, were codon optimized and examined by fluorescence microscopy and plate reader assays. Notably, protein fusions of the RFPs to FtsZ were constructed by direct transformation of linear Gibson assembly (isothermal assembly) products, a method that speeds up the strain construction process significantly. Our data show that mCherry is the fastest-maturing RFP inS. pneumoniaeand is best suited for studying gene expression, while mKate2 and TagRFP are more stable and are the preferred choices for protein localization studies. The RFPs described here will be useful for cell biology studies that require multicolor labeling inS. pneumoniaeand related organisms.

scholarly journals Benchmarking Various Green Fluorescent Protein Variants in Bacillus subtilis, Streptococcus pneumoniae, and Lactococcus lactis for Live Cell Imaging

2013 ◽  
Vol 79 (20) ◽  
pp. 6481-6490 ◽  
Author(s):  
Wout Overkamp ◽  
Katrin Beilharz ◽  
Ruud Detert Oude Weme ◽  
Ana Solopova ◽  
Harma Karsens ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Green Fluorescent Protein ◽  
Streptococcus Pneumoniae ◽  
Lactococcus Lactis ◽  
Cell Biology ◽  
Fluorescent Protein ◽  
Protein Localization ◽  
Experimental Conditions ◽  
Content Type ◽  
Green Fluorescent

ABSTRACTGreen fluorescent protein (GFP) offers efficient ways of visualizing promoter activity and protein localizationin vivo, and many different variants are currently available to study bacterial cell biology. Which of these variants is best suited for a certain bacterial strain, goal, or experimental condition is not clear. Here, we have designed and constructed two “superfolder” GFPs with codon adaptation specifically forBacillus subtilisandStreptococcus pneumoniaeand have benchmarked them against five other previously available variants of GFP inB. subtilis,S. pneumoniae, andLactococcus lactis, using promoter-gfpfusions. Surprisingly, the best-performing GFP under our experimental conditions inB. subtiliswas the one codon optimized forS. pneumoniaeandvice versa. The data and tools described in this study will be useful for cell biology studies in low-GC-rich Gram-positive bacteria.

scholarly journals Use of mCherry Red Fluorescent Protein for Studies of Protein Localization and Gene Expression in Clostridium difficile

2014 ◽  
Vol 81 (5) ◽  
pp. 1652-1660 ◽  
Author(s):  
Eric M. Ransom ◽  
Craig D. Ellermeier ◽  
David S. Weiss
Keyword(s):  
Gene Expression ◽  
Clostridium Difficile ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Protein Localization ◽  
Anaerobic Bacteria ◽  
Gc Content ◽  
Inducible Promoter ◽  
Developed Countries ◽  
Content Type

ABSTRACTFluorescent proteins are powerful reporters in biology, but most require O2for chromophore maturation, making them inherently difficult to use in anaerobic bacteria.Clostridium difficile, a strict anaerobe with a genomic GC content of only 29%, is the leading cause of hospital-acquired diarrhea in developed countries, and new methods for studying this pathogen are sorely needed. We recently demonstrated that a cyan fluorescent protein called CFPoptthat has been codon optimized for production in low-GC bacteria can be used to study protein localization inC. difficileprovided the cells are fixed prior to exposure to air. We describe here a codon-optimized variant of mCherry (mCherryOpt) that exhibits faster acquisition of fluorescence and a better signal-to-noise ratio than CFPopt. We utilizedmCherryOptto construct plasmids for studying protein localization (pRAN473) and gene expression (pDSW1728) inC. difficile. Plasmid pRAN473 is anmCherryOptfusion vector with a tetracycline-inducible promoter. To document its biological utility, we demonstrated septal localization of two cell division proteins, MldA and ZapA. Plasmid pDSW1728 is designed for cloning a promoter of interest upstream ofmCherryOpt. As proof of principle, we studied the expression of thepdaVoperon, which is required for lysozyme resistance. In confirmation and extension of previous reports, we found that expression of thepdaVoperon requires the alternative sigma factor σvand that induction by lysozyme is dose dependent and uniform across the population of lysozyme-treated cells.

scholarly journals Reconstruction ofmreBExpression in Staphylococcus aureus via a Collection of New Integrative Plasmids

2014 ◽  
Vol 80 (13) ◽  
pp. 3868-3878 ◽  
Author(s):  
Ana Yepes ◽  
Gudrun Koch ◽  
Andrea Waldvogel ◽  
Juan-Carlos Garcia-Betancur ◽  
Daniel Lopez
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Biology ◽  
Genetic Manipulation ◽  
Protein Localization ◽  
Antibiotic Resistance Genes ◽  
Wall Material ◽  
Content Type ◽  
Genetic Manipulations ◽  
Discrete Structures

ABSTRACTProtein localization has been traditionally explored in unicellular organisms, whose ease of genetic manipulation facilitates molecular characterization. The two rod-shaped bacterial modelsEscherichia coliandBacillus subtilishave been prominently used for this purpose and have displaced other bacteria whose challenges for genetic manipulation have complicated any study of cell biology. Among these bacteria is the spherical pathogenic bacteriumStaphylococcus aureus. In this report, we present a new molecular toolbox that facilitates gene deletion in staphylococci in a 1-step recombination process and additional vectors that facilitate the insertion of diverse reporter fusions into newly identified neutral loci of theS. aureuschromosome. Insertion of the reporters does not add any antibiotic resistance genes to the chromosomes of the resultant strains, thereby making them amenable for further genetic manipulations. We used this toolbox to reconstitute the expression ofmreBinS. aureus, a gene that encodes an actin-like cytoskeletal protein which is absent in coccal cells and is presumably lost during the course of speciation. We observed that inS. aureus, MreB is organized in discrete structures in association with the membrane, leading to an unusual redistribution of the cell wall material. The production of MreB also caused cell enlargement, but it did not revert staphylococcal shape. We present interactions of MreB with key staphylococcal cell wall-related proteins. This work facilitates the useS. aureusas a model system in exploring diverse aspects of cellular microbiology.

scholarly journals Immunization with Pneumococcal Polysaccharide Serotype 3 and Lipopolysaccharide Modulates Lung and Liver Inflammation during a Virulent Streptococcus pneumoniae Infection in Mice

2013 ◽  
Vol 20 (5) ◽  
pp. 639-650 ◽  
Author(s):  
Katherine H. Restori ◽  
Mary J. Kennett ◽  
A. Catharine Ross
Keyword(s):  
Gene Expression ◽  
Streptococcus Pneumoniae ◽  
Acute Phase ◽  
Acute Phase Proteins ◽  
Expression Profiles ◽  
Cytokine Gene Expression ◽  
Dependent Manner ◽  
Pneumonia Severity ◽  
Content Type ◽  
Amyloid A

ABSTRACTVaccination reduces morbidity and mortality from pneumonia, but its effect on the tissue-level response to infection is still poorly understood. We evaluated pneumonia disease progression, acute-phase response, and lung gene expression profiles in mice inoculated intranasally with virulent Gram-positiveStreptococcus pneumoniaeserotype 3 (ST 3) with and without prior immunization with pneumococcal polysaccharide ST 3 (PPS3) or after coimmunization with PPS3 and a low dose of lipopolysaccharide (PPS3+LPS). Pneumonia severity was assessed in the acute phase at 5, 12, 24 and 48 h postinoculation (p.i.) and in the resolution phase at 7 days p.i. Primary PPS3-specific antibody production was upregulated, and IgM binding to pneumococci increased in PPS3-immunized mice. Immunizations with PPS3 or PPS3+LPS decreased bacterial recovery in the lung and blood at 24 and 48 h and increased survival. Microarray analysis of whole-lung RNA revealed significant changes in the acute-phase protein serum amyloid A (SAA) levels between noninfected and infected mice, and these changes were attenuated by immunization. SAA transcripts were higher in the liver and lungs of infected controls, and SAA protein was elevated in serum but decreased in PPS3-immunized mice. Thus, during a virulent pneumonia infection, prior immunization with PPS3 in an IgM-dependent manner as well as immunization with PPS3+LPS attenuated pneumonia severity and promoted resolution of infection, concomitant with significant regulation of cytokine gene expression levels in the lungs and acute-phase proteins in the lungs, liver, and serum.

scholarly journals Endopeptidase PepO Regulates the SpeB Cysteine Protease and Is Essential for the Virulence of Invasive M1T1Streptococcus pyogenes

2018 ◽  
Vol 200 (8) ◽  
Author(s):  
Stephan Brouwer ◽  
Amanda J. Cork ◽  
Cheryl-Lynn Y. Ong ◽  
Timothy C. Barnett ◽  
Nicholas P. West ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Phase ◽  
Cysteine Protease ◽  
Genetic Regulation ◽  
Bacterial Pathogen ◽  
Targeted Mutagenesis ◽  
Human Neutrophils ◽  
Content Type ◽  
Wide Range ◽  
Human Infections

ABSTRACTStreptococcus pyogenes(group AStreptococcus[GAS]) causes a wide range of human infections. The pathogenesis of GAS infections is dependent on the temporal expression of numerous secreted and surface-associated virulence factors that interact with host proteins. Streptococcal pyrogenic exotoxin B (SpeB) is one of the most extensively studied toxins produced by GAS, and the coordinate growth phase-dependent regulation ofspeBexpression is linked to disease severity phenotypes. Here, we identified the endopeptidase PepO as a novel growth phase-dependent regulator of SpeB in the invasive GAS M1 serotype strain 5448. By using transcriptomics followed by quantitative reverse transcriptase PCR and Western blot analyses, we demonstrate through targeted mutagenesis that PepO influences growth phase-dependent induction ofspeBgene expression. Compared to wild-type and complemented mutant strains, we demonstrate that the 5448ΔpepOmutant strain is more susceptible to killing by human neutrophils and is attenuated in virulence in a murine model of invasive GAS infection. Our results expand the complex regulatory network that is operating in GAS to control SpeB production and suggest that PepO is a virulence requirement during GAS M1T1 strain 5448 infections.IMPORTANCEDespite the continuing susceptibility ofS. pyogenesto penicillin, this bacterial pathogen remains a leading infectious cause of global morbidity and mortality. A particular subclone of the M1 serotype (M1T1) has persisted globally for decades as the most frequently isolated serotype from patients with invasive and noninvasive diseases in Western countries. One of the key GAS pathogenicity factors is the potent broad-spectrum cysteine protease SpeB. Although there has been extensive research interest on the regulatory mechanisms that controlspeBgene expression, its genetic regulation is not fully understood. Here, we identify the endopeptidase PepO as a new regulator ofspeBgene expression in the globally disseminated M1T1 clone and as being essential for virulence.

scholarly journals Syndecan-1 Promotes Streptococcus pneumoniae Corneal Infection by Facilitating the Assembly of Adhesive Fibronectin Fibrils

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Akiko Jinno ◽  
Atsuko Hayashida ◽  
Howard F. Jenkinson ◽  
Pyong Woo Park
Keyword(s):  
Streptococcus Pneumoniae ◽  
Basement Membrane ◽  
Cell Surface ◽  
Host Cell ◽  
Cell Biology ◽  
Bacterial Attachment ◽  
Microbial Pathogens ◽  
Surface Attachment ◽  
Content Type ◽  
Corneal Infection

ABSTRACT Subversion of heparan sulfate proteoglycans (HSPGs) is thought to be a common virulence mechanism shared by many microbial pathogens. The prevailing assumption is that pathogens co-opt HSPGs as cell surface attachment receptors or as inhibitors of innate host defense. However, there are few data that clearly support this idea in vivo. We found that deletion of syndecan-1 (Sdc1), a major cell surface HSPG of epithelial cells, causes a gain of function in a mouse model of scarified corneal infection, where Sdc1−/− corneas were significantly less susceptible to Streptococcus pneumoniae infection. Administration of excess Sdc1 ectodomains significantly inhibited S. pneumoniae corneal infection, suggesting that Sdc1 promotes infection as a cell surface attachment receptor. However, S. pneumoniae did not interact with Sdc1 and Sdc1 was shed upon S. pneumoniae infection, indicating that Sdc1 does not directly support S. pneumoniae adhesion. Instead, Sdc1 promoted S. pneumoniae adhesion by driving the assembly of fibronectin (FN) fibrils in the corneal basement membrane to which S. pneumoniae attaches when infecting injured corneas. S. pneumoniae specifically bound to corneal FN via PavA, and PavA deletion significantly attenuated S. pneumoniae virulence in the cornea. Excess Sdc1 ectodomains inhibited S. pneumoniae corneal infection by binding to the Hep II domain and interfering with S. pneumoniae PavA binding to FN. These findings reveal a previously unknown virulence mechanism of S. pneumoniae where key extracellular matrix (ECM) interactions and structures that are essential for host cell homeostasis are exploited for bacterial pathogenesis. IMPORTANCE Bacterial pathogens have evolved several ingenious mechanisms to subvert host cell biology for their pathogenesis. Bacterial attachment to the host ECM establishes a niche to grow and is considered one of the critical steps of infection. This pathogenic mechanism entails coordinated assembly of the ECM by the host to form the ECM structure and organization that are specifically recognized by bacteria for their adhesion. We serendipitously discovered that epithelial Sdc1 facilitates the assembly of FN fibrils in the corneal basement membrane and that this normal biological function of Sdc1 has detrimental consequences for the host in S. pneumoniae corneal infection. Our studies suggest that bacterial subversion of the host ECM is more complex than previously appreciated.

scholarly journals Cumate-Inducible Gene Expression System for Sphingomonads and Other Alphaproteobacteria

2013 ◽  
Vol 79 (21) ◽  
pp. 6795-6802 ◽  
Author(s):  
Andreas Kaczmarczyk ◽  
Julia A. Vorholt ◽  
Anne Francez-Charlot
Keyword(s):  
Gene Expression ◽  
Caulobacter Crescentus ◽  
Paracoccus Denitrificans ◽  
Expression System ◽  
Model Organisms ◽  
Inducible Gene Expression ◽  
Gene Expression System ◽  
Content Type ◽  
Wide Range ◽  
Inducible Gene

ABSTRACTTunable promoters represent a pivotal genetic tool for a wide range of applications. Here we present such a system for sphingomonads, a phylogenetically diverse group of bacteria that have gained much interest for their potential in bioremediation and their use in industry and for which no dedicated inducible gene expression system has been described so far. A strong, constitutive synthetic promoter was first identified through a genetic screen and subsequently combined with the repressor and the operator sites of thePseudomonas putidaF1cym/cmtsystem. The resulting promoter, termed PQ5, responds rapidly to the inducer cumate and shows a maximal induction ratio of 2 to 3 orders of magnitude in the different sphingomonads tested. Moreover, it was also functional in otherAlphaproteobacteria, such as the model organismsCaulobacter crescentus,Paracoccus denitrificans, andMethylobacterium extorquens. In the noninduced state, expression from PQ5is low enough to allow gene depletion analysis, as demonstrated with the essential genephyPofSphingomonassp. strain Fr1. A set of PQ5-based plasmids has been constructed allowing fusions to affinity tags or fluorescent proteins.

scholarly journals Intracellular Imaging with Genetically Encoded RNA-based Molecular Sensors

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 233 ◽  
Author(s):  
Zhining Sun ◽  
Tony Nguyen ◽  
Kathleen McAuliffe ◽  
Mingxu You
Keyword(s):  
Cell Biology ◽  
Design Principle ◽  
Fluorescent Proteins ◽  
Rna Recognition ◽  
Molecular Sensors ◽  
Intracellular Imaging ◽  
Biological Targets ◽  
Target Analytes ◽  
Wide Range ◽  
Reporting Systems

Genetically encodable sensors have been widely used in the detection of intracellular molecules ranging from metal ions and metabolites to nucleic acids and proteins. These biosensors are capable of monitoring in real-time the cellular levels, locations, and cell-to-cell variations of the target compounds in living systems. Traditionally, the majority of these sensors have been developed based on fluorescent proteins. As an exciting alternative, genetically encoded RNA-based molecular sensors (GERMS) have emerged over the past few years for the intracellular imaging and detection of various biological targets. In view of their ability for the general detection of a wide range of target analytes, and the modular and simple design principle, GERMS are becoming a popular choice for intracellular analysis. In this review, we summarize different design principles of GERMS based on various RNA recognition modules, transducer modules, and reporting systems. Some recent advances in the application of GERMS for intracellular imaging are also discussed. With further improvement in biostability, sensitivity, and robustness, GERMS can potentially be widely used in cell biology and biotechnology.

scholarly journals Indoleamine 2,3-Dioxygenase, Tryptophan Catabolism, and Mycobacterium avium subsp. paratuberculosis: a Model for Chronic Mycobacterial Infections

2011 ◽  
Vol 79 (9) ◽  
pp. 3821-3832 ◽  
Author(s):  
Karren M. Plain ◽  
Kumudika de Silva ◽  
John Earl ◽  
Douglas J. Begg ◽  
Auriol C. Purdie ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mycobacterium Avium ◽  
Protein Localization ◽  
Clinical Disease ◽  
Intracellular Pathogen ◽  
Mrna Levels ◽  
Content Type ◽  
Mycobacterial Infections ◽  
Indoleamine 2,3 Dioxygenase ◽  
Gene And Protein Expression

ABSTRACTVirulent mycobacterial infections progress slowly, with a latent period that leads to clinical disease in a proportion of cases.Mycobacterium aviumsubsp.paratuberculosisis an intracellular pathogen that causes paratuberculosis or Johne's disease (JD), a chronic intestinal disease of ruminants. Indoleamine 2,3-dioxygenase (IDO), an enzyme that regulates tryptophan metabolism, was originally reported to have a role in intracellular pathogen killing and has since been shown to have an important immunoregulatory role in chronic immune diseases. Here we demonstrate an association between increased IDO levels and progression to clinical mycobacterial disease in a natural host, characterizing gene expression, protein localization, and functional effects. IDO mRNA levels were significantly increased inM. aviumsubsp.paratuberculosis-infected monocytic cells. Levels of both IDO gene and protein expression were significantly upregulated within the affected tissues of sheep with JD, particularly at the site of primary infection, the ileum, of animals with severe multibacillary disease. Lesion severity was correlated with the level of IDO gene expression. IDO gene expression was also increased in the peripheral blood cells ofM. aviumsubsp.paratuberculosis-exposed sheep and cattle. IDO breaks down tryptophan, and systemic increases were functional, as shown by decreased plasma tryptophan levels, which correlated with the onset of clinical signs, a stage well known to be associated with Th1 immunosuppression. IDO may be involved in downregulating immune responses toM. aviumsubsp.paratuberculosisand other virulent mycobacteria, which may be an example of the pathogen harnessing host immunoregulatory pathways to aid survival. These findings raise new questions about the host-mycobacterium interactions in the progression from latent to clinical disease.

scholarly journals In VivoProgrammed Gene Expression Based on Artificial Quorum Networks

2015 ◽  
Vol 81 (15) ◽  
pp. 4984-4992 ◽  
Author(s):  
Teng Chu ◽  
Yajun Huang ◽  
Mingyu Hou ◽  
Qiyao Wang ◽  
Jingfan Xiao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Cell Density ◽  
Protective Antigen ◽  
Expression System ◽  
Edwardsiella Tarda ◽  
Content Type ◽  
Genetic Components ◽  
Wide Range

ABSTRACTThe quorum sensing (QS) system, as a well-functioning population-dependent gene switch, has been widely applied in many gene circuits in synthetic biology. In our work, an efficient cell density-controlled expression system (QS) was established via engineering of theVibrio fischeri luxI-luxRquorum sensing system. In order to achievein vivoprogrammed gene expression, a synthetic binary regulation circuit (araQS) was constructed by assembling multiple genetic components, including the quorum quenching protein AiiA and the arabinose promoter ParaBAD, into the QS system.In vitroexpression assays verified that the araQS system was initiated only in the absence of arabinose in the medium at a high cell density.In vivoexpression assays confirmed that the araQS system presented anin vivo-triggered and cell density-dependent expression pattern. Furthermore, the araQS system was demonstrated to function well in different bacteria, indicating a wide range of bacterial hosts for use. To explore its potential applicationsin vivo, the araQS system was used to control the production of a heterologous protective antigen in an attenuatedEdwardsiella tardastrain, which successfully evoked efficient immune protection in a fish model. This work suggested that the araQS system could program bacterial expressionin vivoand might have potential uses, including, but not limited to, bacterial vector vaccines.

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