scholarly journals Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Michael Frahm ◽  
Sebastian Felgner ◽  
Dino Kocijancic ◽  
Manfred Rohde ◽  
Michael Hensel ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Tumor Targeting ◽  
Antitumor Effect ◽  
Treatment Options ◽  
Tumor Therapy ◽  
Therapeutic Benefit ◽  
Industrialized Countries ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Therapeutic Molecules

ABSTRACTIncreasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria likeSalmonella entericaserovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenicS. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbBmutants) ofSalmonellawere investigated for efficiency in tumor therapy. Of such variants, the ΔrfaDand ΔrfaGdeep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into thearaBADlocus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium.IMPORTANCECancer has become the second most frequent cause of death in industrialized countries. This and the drawbacks of routine therapies generate an urgent need for novel treatment options. Applying appropriately modifiedS. Typhimurium for therapy represents the major challenge of bacterium-mediated tumor therapy. In the present study, we demonstrated thatSalmonellabacteria conditionally modified in their LPS phenotype exhibit a safe tumor-targeting phenotype. Moreover, they could represent a suitable vehicle to shuttle therapeutic compounds directly into cancerous tissue without harming the host.

scholarly journals Evidence of Metabolic Switching and Implications for Food Safety from the Phenome(s) of Salmonella enterica Serovar Typhimurium DT104 Cultured at Selected Points across the Pork Production Food Chain

2013 ◽  
Vol 79 (18) ◽  
pp. 5437-5449 ◽  
Author(s):  
Marta Martins ◽  
Matthew P. McCusker ◽  
Evonne M. McCabe ◽  
Denis O'Leary ◽  
Geraldine Duffy ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Food Safety ◽  
Food Chain ◽  
Salmonella Enterica ◽  
Treatment Options ◽  
Multidrug Resistant ◽  
Human Infection ◽  
Content Type ◽  
Pork Production ◽  
Serovar Typhimurium

ABSTRACTSalmonella entericaserovar Typhimurium DT104 is a recognized food-borne pathogen that displays a multidrug-resistant phenotype and that is associated with systemic infections. At one extreme of the food chain, this bacterium can infect humans, limiting the treatment options available and thereby contributing to increased morbidity and mortality. Although the antibiotic resistance profile is well defined, little is known about other phenotypes that may be expressed by this pathogen at key points across the pork production food chain. In this study, 172Salmonella entericaserovar Typhimurium DT104/DT104b isolated from an extensive “farm-to-fork” surveillance study, focusing on the pork food chain, were characterized in detail. Isolates were cultured from environmental, processing, retail, and clinical sources, and the study focused on phenotypes that may have contributed to persistence/survival in these different niches. Molecular subtypes, along with antibiotic resistance profiles, tolerance to biocides, motility, and biofilm formation, were determined. As a basis for human infection, acid survival and the ability to utilize a range of energy sources and to adhere to and/or invade Caco-2 cells were also studied. Comparative alterations to biocide tolerance were observed in isolates from retail.l-Tartaric acid andd-mannose-1-phosphate induced the formation of biofilms in a preselected subset of strains, independent of their origin. All clinical isolates were motile and demonstrated an enhanced ability to survive in acidic conditions. Our data report on a diverse phenotype, expressed byS. Typhimurium isolates cultured from the pork production food chain. Extending our understanding of the means by which this pathogen adapts to environmental niches along the “farm-to-fork” continuum will facilitate the protection of vulnerable consumers through targeted improvements in food safety measures.

scholarly journals Whole-Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhimurium Strain UPM 260, Isolated from a Broiler Chicken in Perak, Malaysia

2017 ◽  
Vol 5 (46) ◽  
Author(s):  
Najwa Syahirah Roslan ◽  
Shagufta Jabeen ◽  
Nurulfiza Mat Isa ◽  
Abdul Rahman Omar ◽  
Mohd Hair Bejo ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Salmonella Enterica ◽  
Broiler Chicken ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Content Type ◽  
Typhimurium Strain ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica subsp. enterica serovar Typhimurium is one of several well-categorized Salmonella serotypes recognized globally. Here, we report the whole-genome sequence of S. Typhimurium strain UPM 260, isolated from a broiler chicken.

scholarly journals Association of a Protective Monoclonal IgA with the O Antigen of Salmonella enterica Serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity

2012 ◽  
Vol 80 (7) ◽  
pp. 2454-2463 ◽  
Author(s):  
Stephen J. Forbes ◽  
Daniel Martinelli ◽  
Chyongere Hsieh ◽  
Jeffrey G. Ault ◽  
Michael Marko ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Integrity ◽  
Effector Proteins ◽  
Content Type ◽  
O Antigen ◽  
Serovar Typhimurium ◽  
Type 3

ABSTRACTInvasion of intestinal epithelial cells bySalmonella entericaserovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as theSalmonellapathogenicity island 1 (SPI-1) type 3 secretion system (T3SS). By a mechanism that remains poorly understood, entry ofS. Typhimurium into epithelial cells is inhibited by Sal4, a monoclonal, polymeric IgA antibody that binds an immunodominant epitope within the O-antigen (O-Ag) component of lipopolysaccharide. In this study, we investigated how the binding of Sal4 to the surface ofS. Typhimurium influences T3SS activity, bacterial energetics, and outer membrane integrity. We found that Sal4 treatment impaired T3SS-mediated translocon formation and attenuated the delivery of tagged effector proteins into epithelial cells. Sal4 treatment coincided with a partial reduction in membrane energetics and intracellular ATP levels, possibly explaining the impairment in T3SS activity. Sal4's effects on bacterial secretion and energetics occurred concurrently with an increase in O-Ag levels in culture supernatants, alterations in outer membrane permeability, and changes in surface ultrastructure, as revealed by transmission electron microscopy and cryo-electron microscopy. We propose that Sal4, by virtue of its ability to bind and cross-link the O-Ag, induces a form of outer membrane stress that compromises the integrity of theS. Typhimurium cell envelope and temporarily renders the bacterium avirulent.

scholarly journals Draft Genome Sequence of Lactobacillus fermentum Lf2, an Exopolysaccharide-Producing Strain Isolated from Argentine Cheese

2018 ◽  
Vol 7 (18) ◽  
Author(s):  
Hugh M. B. Harris ◽  
Elisa C. Ale ◽  
Jorge A. Reinheimer ◽  
Ana G. Binetti ◽  
Paul W. O’Toole
Keyword(s):  
Genome Sequence ◽  
Salmonella Enterica ◽  
Draft Genome ◽  
Protective Role ◽  
Lactobacillus Fermentum ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Serovar Typhimurium ◽  
High Concentrations

Lactobacillus fermentum Lf2, an Argentine cheese isolate, can produce high concentrations of exopolysaccharides (EPS). These EPS were shown to improve the texture and rheology of yogurt, as well as to play a protective role in mice exposed to Salmonella enterica serovar Typhimurium.

scholarly journals Regulation of RamA by RamR in Salmonella enterica Serovar Typhimurium: Isolation of a RamR Superrepressor

2012 ◽  
Vol 56 (11) ◽  
pp. 6037-6040 ◽  
Author(s):  
Vito Ricci ◽  
Stephen J. W. Busby ◽  
Laura J. V. Piddock
Keyword(s):  
Transcription Factor ◽  
Salmonella Enterica ◽  
Fluorescent Protein ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Promoter Sequence ◽  
Palindromic Sequence ◽  
Content Type ◽  
Gfp Reporter ◽  
Serovar Typhimurium ◽  
Green Fluorescent

ABSTRACTRamA is a transcription factor involved in regulating multidrug resistance inSalmonella entericaserovar Typhimurium SL1344. Green fluorescent protein (GFP) reporter fusions were exploited to investigate the regulation of RamA expression by RamR. We show that RamR represses theramApromoter by binding to a palindromic sequence and describe a superrepressor RamR mutant that binds to theramApromoter sequence more efficiently, thus exhibiting aramAinactivated phenotype.

scholarly journals Curcumin Reduces the Motility of Salmonella enterica Serovar Typhimurium by Binding to the Flagella, Thereby Leading to Flagellar Fragility and Shedding

2016 ◽  
Vol 198 (13) ◽  
pp. 1798-1811 ◽  
Author(s):  
Sandhya Amol Marathe ◽  
Arjun Balakrishnan ◽  
Vidya Devi Negi ◽  
Deepika Sakorey ◽  
Nagasuma Chandra ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Binding Assay ◽  
Protein A ◽  
Intestinal Barrier ◽  
Site Directed Mutagenesis ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Flagellar Filament ◽  
Fluorescence Binding ◽  
Fluorescence Binding Assay

ABSTRACTOne of the important virulence properties of the pathogen is its ability to travel to a favorable environment, cross the viscous mucus barrier (intestinal barrier for enteric pathogens), and reach the epithelia to initiate pathogenesis with the help of an appendage, like flagella. Nonetheless, flagella can act as an “Achilles heel,” revealing the pathogen's presence to the host through the stimulation of innate and adaptive immune responses. We assessed whether curcumin, a dietary polyphenol, could alter the motility ofSalmonella, a foodborne pathogen. It reduced the motility ofSalmonella entericaserovar Typhimurium by shortening the length of the flagellar filament (from ∼8 μm to ∼5 μm) and decreasing its density (4 or 5 flagella/bacterium instead of 8 or 9 flagella/bacterium). Upon curcumin treatment, the percentage of flagellated bacteria declined from ∼84% to 59%. However, no change was detected in the expression of the flagellin gene and protein. A fluorescence binding assay demonstrated binding of curcumin to the flagellar filament. This might make the filament fragile, breaking it into smaller fragments. Computational analysis predicted the binding of curcumin, its analogues, and its degraded products to a flagellin molecule at an interface between domains D1 and D2. Site-directed mutagenesis and a fluorescence binding assay confirmed the binding of curcumin to flagellin at residues ASN120, ASP123, ASN163, SER164, ASN173, and GLN175.IMPORTANCEThis work, to our knowledge the first report of its kind, examines how curcumin targets flagellar density and affects the pathogenesis of bacteria. We found that curcumin does not affect any of the flagellar synthesis genes. Instead, it binds to the flagellum and makes it fragile. It increases the torsional stress on the flagellar filament that then breaks, leaving fewer flagella around the bacteria. Flagella, which are crucial ligands for Toll-like receptor 5, are some of the most important appendages ofSalmonella. Curcumin is an important component of turmeric, which is a major spice used in Asian cooking. The loss of flagella can, in turn, change the pathogenesis of bacteria, making them more robust and fit in the host.

scholarly journals Role of sapA and yfgA in Susceptibility to Antibody-Mediated Complement-Dependent Killing and Virulence of Salmonella enterica Serovar Typhimurium

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Edna M. Ondari ◽  
Jennifer N. Heath ◽  
Elizabeth J. Klemm ◽  
Gemma Langridge ◽  
Lars Barquist ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Protein Translocation ◽  
Invasive Disease ◽  
Immune Serum ◽  
Insertion Mutant ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Serum Killing ◽  
Increased Sensitivity

ABSTRACT The ST313 pathovar of Salmonella enterica serovar Typhimurium contributes to a high burden of invasive disease among African infants and HIV-infected adults. It is characterized by genome degradation (loss of coding capacity) and has increased resistance to antibody-dependent complement-mediated killing compared with enterocolitis-causing strains of S. Typhimurium. Vaccination is an attractive disease-prevention strategy, and leading candidates focus on the induction of bactericidal antibodies. Antibody-resistant strains arising through further gene deletion could compromise such a strategy. Exposing a saturating transposon insertion mutant library of S. Typhimurium to immune serum identified a repertoire of S. Typhimurium genes that, when interrupted, result in increased resistance to serum killing. These genes included several involved in bacterial envelope biogenesis, protein translocation, and metabolism. We generated defined mutant derivatives using S. Typhimurium SL1344 as the host. Based on their initial levels of enhanced resistance to killing, yfgA and sapA mutants were selected for further characterization. The S. Typhimurium yfgA mutant lost the characteristic Salmonella rod-shaped appearance, exhibited increased sensitivity to osmotic and detergent stress, lacked very long lipopolysaccharide, was unable to invade enterocytes, and demonstrated decreased ability to infect mice. In contrast, the S. Typhimurium sapA mutants had similar sensitivity to osmotic and detergent stress and lipopolysaccharide profile and an increased ability to infect enterocytes compared with the wild type, but it had no increased ability to cause in vivo infection. These findings indicate that increased resistance to antibody-dependent complement-mediated killing secondary to genetic deletion is not necessarily accompanied by increased virulence and suggest the presence of different mechanisms of antibody resistance.

scholarly journals Draft Genome Sequences of 20 Salmonella enterica subsp. enterica Serovar Typhimurium Strains Isolated from Swine in Santa Catarina, Brazil

2018 ◽  
Vol 6 (16) ◽  
pp. e00232-18 ◽  
Author(s):  
Amanda Aparecida Seribelli ◽  
Miliane Rodrigues Frazão ◽  
Júlia Cunha Gonzales ◽  
Guojie Cao ◽  
Maria Sanchez Leon ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Draft Genome ◽  
Genome Sequences ◽  
Santa Catarina ◽  
Content Type ◽  
High Incidence ◽  
Serovar Typhimurium

ABSTRACT Salmonellosis is a disease with a high incidence worldwide, and Salmonella enterica subsp. enterica serovar Typhimurium is one of the most clinically important serovars. We report here the draft genome sequences of 20 S. Typhimurium strains isolated from swine in Santa Catarina, Brazil. These draft genomes will improve our understanding of S. Typhimurium in Brazil.

scholarly journals Terminal Deoxynucleotidyl Transferase Is Not Required for Antibody Response to Polysaccharide Vaccines againstStreptococcus pneumoniaeandSalmonella entericaSerovar Typhi

2018 ◽  
Vol 86 (9) ◽  
Author(s):  
Vivek Belde ◽  
Matthew P. Cravens ◽  
Dania Gulandijany ◽  
Justin A. Walker ◽  
Isabel Palomo-Caturla ◽  
...  
Keyword(s):  
Antibody Response ◽  
B Cell ◽  
Salmonella Enterica ◽  
Passive Immunization ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Human Infants ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTB cell antigen receptor (BCR) diversity increases by several orders of magnitude due to the action of terminal deoxynucleotidyl transferase (TdT) during V(D)J recombination. Unlike adults, infants have limited BCR diversity, in part due to reduced expression of TdT. Since human infants and young mice respond poorly to polysaccharide vaccines, such as the pneumococcal polysaccharide vaccine Pneumovax23 and Vi polysaccharide (ViPS) ofSalmonella entericaserovar Typhi, we tested the contribution of TdT-mediated BCR diversity in response to these vaccines. We found that TdT+/−and TdT−/−mice generated comparable antibody responses to Pneumovax23 and survivedStreptococcus pneumoniaechallenge. Moreover, passive immunization of B cell-deficient mice with serum from Pneumovax23-immunized TdT+/−or TdT−/−mice conferred protection. TdT+/−and TdT−/−mice generated comparable levels of anti-ViPS antibodies and antibody-dependent, complement-mediated bactericidal activity againstS. Typhiin vitro. To test the protective immunity conferred by ViPS immunizationin vivo, TdT+/−and TdT−/−mice were challenged with a chimericSalmonella entericaserovar Typhimurium strain expressing ViPS, since mice are nonpermissive hosts forS. Typhi infection. Compared to their unimmunized counterparts, immunized TdT+/−and TdT−/−mice challenged with ViPS-expressingS. Typhimurium exhibited a significant reduction in the bacterial burden and liver pathology. These data suggest that the impaired antibody response to the Pneumovax23 and ViPS vaccines in the young is not due to limited TdT-mediated BCR diversification.

scholarly journals Display of Recombinant Proteins on Bacterial Outer Membrane Vesicles by Using Protein Ligation

2018 ◽  
Vol 84 (8) ◽  
pp. e02567-17 ◽  
Author(s):  
H. Bart van den Berg van Saparoea ◽  
Diane Houben ◽  
Marien I. de Jonge ◽  
Wouter S. P. Jong ◽  
Joen Luirink
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Vesicles ◽  
Therapeutic Agents ◽  
Outer Membrane Vesicles ◽  
High Density ◽  
Content Type ◽  
Protein Ligation ◽  
Serovar Typhimurium

ABSTRACT The Escherichia coli virulence factor hemoglobin protease (Hbp) has been engineered into a surface display system that can be expressed to high density on live E. coli and Salmonella enterica serovar Typhimurium cells or derived outer membrane vesicles (OMVs). Multiple antigenic sequences can be genetically fused into the Hbp core structure for optimal exposure to the immune system. Although the Hbp display platform is relatively tolerant, increasing the number, size, and complexity of integrated sequences generally lowers the expression of the fused constructs and limits the density of display. This is due to the intricate mechanism of Hbp secretion across the outer membrane and the efficient quality control of translocation-incompetent chimeric Hbp molecules in the periplasm. To address this shortcoming, we explored the coupling of purified proteins to the Hbp carrier after its translocation across the outer membrane using the recently developed SpyTag/SpyCatcher protein ligation system. As expected, fusion of the small SpyTag to Hbp did not hamper display on OMVs. Subsequent addition of purified proteins fused to the SpyCatcher domain resulted in efficient covalent coupling to Hbp-SpyTag. Using in addition the orthogonal SnoopTag/SnoopCatcher system, multiple antigen modules could be coupled to Hbp in a sequential ligation strategy. Not only antigens proved suitable for Spy-mediated ligation but also nanobodies. Addition of this functionality to the platform might allow the targeting of live bacterial or OMV vaccines to certain tissues or immune cells to tailor immune responses.IMPORTANCE Outer membrane vesicles (OMVs) derived from Gram-negative bacteria attract increasing interest in the development of vaccines and therapeutic agents. We aim to construct a semisynthetic OMV platform for recombinant antigen presentation on OMVs derived from attenuated Salmonella enterica serovar Typhimurium cells displaying an adapted Escherichia coli autotransporter, Hbp, at the surface. Although this autotransporter accepts substantial modifications, its capacity with respect to the number, size, and structural complexity of the antigens genetically fused to the Hbp carrier is restricted. Here we describe the application of SpyCatcher/SpyTag protein ligation technology to enzymatically link antigens to Hbp present at high density in OMVs. Protein ligation was apparently unobstructed by the membrane environment and allowed a high surface density of coupled antigens, a property we have shown to be important for vaccine efficacy. The OMV coupling procedure appears versatile and robust, allowing fast production of experimental vaccines and therapeutic agents through a modular plug-and-display procedure.

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