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The Americanization of Old World medicine
Published in Lois N. Magner, Oliver J. Kim, A History of Medicine, 2017
Surgeons returned to private practice with strange ideas about wounds and healing. Maggot therapy, for example, was based on the observation that certain “worms” seemed to cleanse a wound of pus, while ignoring healthy flesh. According to Civil War folklore, soldiers with wounds that glowed in the dark had better survival rates than soldiers with non-glowing wounds. Microbiologists eventually suggested that these observations might have a factual basis. The luminescent bacterium, Photorhabdus luminescens, an insect pathogen, has been investigated as a potential biocontrol agent. Some Photorhabdus strains produce compounds that inhibit the growth of the bacteria that cause infections in open wounds.
Optical Techniques for Imaging of Cell Trafficking
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
Optical imaging methods have been stimulated by the development of genetically engineered fluorescent and bioluminescent markers and new fluorescent probes. The most frequently used bioluminescence markers include the bacterial lux genes of terrestrial Photorhabdus luminescens and marine Vibrio harveyi bacteria, as well as eukaryotic firefly luciferase (Fluc) and Renilla luciferase (Rluc) genes from firefly species (Photinus) and the sea panzy (Renilla reniformis), respectively (1). Recently a new bioluminescent protein Gaussia luciferase (Gluc), has been cloned and shown to have a 200-fold higher signal intensity than Rluc in vivo (2). Fluorescent proteins are genetically encoded, easily imaged reporters crucial in biology and biotechnology (3,4). All the wild-type yellow-to-red fluorescent proteins reported so far are obligately tetrameric and often toxic or disruptive (5,6). Recently, next generation of monomers were reported (7), the latest red version matures more completely, is more tolerant of N-terminal fusions, and is over tenfold more photostable than mRFP1. Three monomers with distinguishable hues from yellow-orange to red-orange have higher quantum efficiencies. Based on the criterion of time, it takes for the emission to drop to 50% of its initial value, tdTomato and mCherry are the best among the generation of red shifted markers. Both are more than tenfold better than mRFPl and nearly as good as EGFP (7).
Engineering Escherichia coli to Combat Cancer
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Carlos Piñero-Lambea, David Ruano-Gallego, Gustavo Bodelón, Beatriz Álvarez, Luis Ángel Fernández
To engineer synthetic (e.g., non-natural) E. coli adhesion, we developed gene expression cassettes consisting in the SA under the control of a constitutive promoter (PN25) for integration as a single copy in the chromosome of E. coli. This allows constant expression of the SA in the absence of exogenous inducers and antibiotics for plasmid maintenance. For site-specific integration in the bacterial chromosome we adapted a markerless gene deletion strategy, enabling sequential manipulation of multiple gene loci, leaving no plasmid sequences (i.e., antibiotic resistance genes) in the chromosome [62]. This technology is based on the insertion of a suicide plasmid bearing homology regions (HRs) of the targeted gene and the subsequent generation of double-strand breaks by expression of I-SceI restriction endonuclease in vivo, which are repaired by homologous recombination, resulting in the specific modification of the targeted gene (Fig. 7.1B). To reduce the natural adhesion capabilities of E. coli K-12, the SA cassette was inserted in the chromosome, replacing the flu gene, which encodes the antigen 43 adhesin [63]. For the same reason, we used an E. coli K-12 strain carrying a deletion of the operon encoding type 1 fimbriae (MG1655ΔfimA-H), named EcM1. Type 1 fimbriae are prominent E. coli adhesins involved in the recognition of mannosylated glycoproteins found on epithelial cell surfaces [59, 64]. The engineered strains were also tagged with a bioluminescent reporter, the luxCDABE operon from Photorhabdus luminescens that allows for luminescent visualization without providing exogenous luciferin [65], which was inserted in the matBCDEF operon. This operon encodes the meningitis-associated and temperature-regulated Mat fimbriae, also termed E. coli common pilus, which is also involved in host cell recognition [66].
Cell-based bioreporter assay coupled to HPLC micro-fractionation in the evaluation of antimicrobial properties of the basidiomycete fungus Pycnoporus cinnabarinus
Published in Pharmaceutical Biology, 2016
Päivi Järvinen, Susanna Nybond, Laurence Marcourt, Emerson Ferreira Queiroz, Jean-Luc Wolfender, Aila Mettälä, Matti Karp, Heikki Vuorela, Pia Vuorela, Annele Hatakka, Päivi Tammela
Bioluminescence-based assays, utilizing different luciferase species, have become important tools for several research fields due to their high sensitive and dynamic range (Galluzzi & Karp 2006). A well-known example is Photinus pyralis (firefly) luciferase, which is widely used as a reporter gene in mammalian cell-based screening assays. Bacterial luciferases, such as Luxαβ from Photorhabdus luminescens, have gained less attention as screening tools despite their clear advantages over eukaryotic luciferases. If the whole bacterial operon (luxCDABE) is utilised in the set-up, the bioluminescence is autonomous and no addition of exogenous substrate is needed. Recently, antibacterial screening assays for identifying DNA gyrase inhibitors as well as translational and transcriptional inhibitors have been developed and utilized in screening campaigns (Moir et al. 2007; Nybond et al. 2013).
An overview of benvitimod for the treatment of psoriasis: a narrative review
Published in Expert Opinion on Pharmacotherapy, 2022
Sarah T Lu, Katherine A Kelly, Steven R Feldman
Benvitimod is a novel topical therapy for psoriasis. The bacteria Photorhabdus luminescens produces the metabolite 3,5-dihydroxy-4-isopropylstilbene (benvitimod) in the Heterorhabditis genus nematode. Benvitimod is an aryl hydrocarbon receptor (AhR) modulating agent[4]. AhR is a ligand-dependent transcription factor that modulates the body’s inflammatory and immune responses in psoriasis. Benvitimod downregulates pro-inflammatory cytokines IL-17A and IL-22, inhibiting keratinocyte hyperproliferation [5,6]. Benvitimod also possesses antioxidant capabilities. The drug may scavenge reactive oxygen species via both intrinsic characteristics, as well as through partial activation of the Nrf2 pathway, which maintains homeostasis[6].
The unforeseen intracellular lifestyle of Enterococcus faecalis in hepatocytes
Published in Gut Microbes, 2022
Natalia Nunez, Aurélie Derré-Bobillot, Nicolas Trainel, Goran Lakisic, Alexandre Lecomte, Françoise Mercier-Nomé, Anne-Marie Cassard, Hélène Bierne, Pascale Serror, Cristel Archambaud
E. faecalis strains OG1RF,49 JH2-2,50 and Symbioflor (a gift from Dr. E. Domann Institute of Medical Microbiology, University of Giessen, Germany) were cultured in brain heart infusion (BHI) at 37°C without aeration. GFP-expressing OG1RF from the pMV158-GFP plasmid was cultured in BHI with 4 µg/ml tetracycline.51E. faecalis strain OG1RF, expressing the luxABCDE (lux) operon from Photorhabdus luminescens, was a gift from Dr D. Lechardeur (Micalis Institute, INRAE, Center de Recherche Ile de France – Jouy-en-Josas – Antony)52 and was cultured in BHI with 20 µg/ml erythromycin.