Legioliulin, a new isocoumarin compound responsible for blue-white autofluorescence in Legionella (Fluoribacter) dumoffii under long-wavelength UV light

Amemura-Maekawa, Junko; Hayakawa, Yoichi; Sugie, Hajime; Moribayashi, Atsuko; Kura, Fumiaki; Chang, Bin; Wada, Akihito; Watanabe, Haruo

doi:10.1016/j.bbrc.2004.08.180

Cited by 30 publications

(26 citation statements)

References 31 publications

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“…Within our enduring interest in the development of new strategies for the synthesis of functionalized heterocycles starting from alkynes, 9 we recently reported a selective and high yielding approach to isocoumarin nucleus. 10 Throughout this study, we observed that some of the obtained isocoumarins displayed significant fluorescence properties, 11 in agreement with the well-known fluorescence features of the isomeric coumarins, documented since the pivotal work of Ronald L. Atkins in 1978. 12 Based on these premises, we were interested to apply our synthetic approach to isocoumarin nucleus for the synthesis of a small library of D--A isocoumarins (Figure 1) as polarity-sensitive fluorophores with enhanced photophysical properties, which can be interesting for biological application as environment-sensitive probes and in advanced functional materials applications.…”

Section: Introductionsupporting

confidence: 88%

Synthesis and photophysical properties of isocoumarin-based D-π-A systems

et al. 2020

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We prepared a small library of polarity-sensitive fluorescent dyes characterized by an isocoumarin core properly functionalized with a conjugated push-pull system. The key step of the synthesis is based on a regio-selective silver(I)/p-TSA co-catalyzed cyclization of 2-alkynylbenzoates recently optimized in our laboratory. The photophysical properties of isocoumarin-based D--A systems have been investigated and a rationale was proposed based on their dipole moments and Hammett constants of the ED and EW groups involved.

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Section: Introductionsupporting

confidence: 88%

Synthesis and photophysical properties of isocoumarin-based D-π-A systems

et al. 2020

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“…Some bacteria exhibit spontaneous emission spectra following excitation at specific wavelengths. The energy of the photons emitted depends on the intrinsic fluorophores retained, such as protein tryptophans, nucleic acids, and coenzymes (19), or on the production of other fluorescent substances (4,21). This work shows for the first time that M. tuberculosis can easily be detected by its intrinsic autofluorescence in the cyan emission spectrum as a brilliant fluorescent bacillus in vitro as well ex vivo during macrophage infection ( Fig.…”

Section: Discussionmentioning

confidence: 77%

Autofluorescence of Mycobacteria as a Tool for Detection of Mycobacterium tuberculosis

et al. 2008

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The diagnosis of tuberculosis in developing countries still relies on direct sputum examination by light microscopy, a method that is easy to perform and that is widely applied. However, because of its poor sensitivity and requirement for significant labor and training, light microscopy examination detects the bacilli in only 45 to 60% of all people whose specimens are culture positive for Mycobacterium tuberculosis. Therefore, new diagnostic methods that would enable the detection of the undiagnosed infected population and allow the early commencement of antituberculosis treatment are needed. In this work, the potential use of mycobacterial cyan autofluorescence for the detection of Mycobacterium tuberculosis was explored. The tubercle bacilli were easily visualized as brilliant fluorescent bacilli by microscopy and were easily tracked ex vivo during macrophage infection. Assays with seeded sputum and a 96-well microplate reader fluorimeter indicated that <10(6) bacilli ml(-1) of sputum could be detected. Moreover, the use of microplates allowed the examination of only 200 microl of sputum per sample without a loss of sensitivity. Treatment with heat or decontaminating chemical agents did not interfere with the autofluorescence assay; on the contrary, they improved the level of bacterial detection. Autofluorescence for the detection of bacilli is rapid and easy to perform compared to other methodologies and can be performed with minimal training, making this method suitable for implementation in developing countries.

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“…Fluorescence intensity was measured across individual cells, which showed diffuse cytoplasmic intensity rather than membrane localization, as is seen in the more common blue/white fluorescence of other Legionella strains. Many Legionella strains exhibit fluorescence under UV as blue/white or red fluorescence but few with green fluorescence have been identified .…”

Section: Patristic Genetic Distances For 27 Legionella Congener Pairsmentioning

confidence: 99%

Legionella clemsonensis sp. nov.: a green fluorescing Legionella strain from a patient with pneumonia

Palmer¹,

Painter²,

Hassler³

et al. 2016

Microbiology and Immunology

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A novel Legionella species was identified based on sequencing, cellular fatty acid analysis, biochemical reactions, and biofilm characterization. Strain D5610 was originally isolated from the bronchial wash of a patient in Ohio, USA. The bacteria were gram-negative, rod-shaped, and exhibited green fluorescence under long wave UV light. Phylogenetic analysis and fatty acid composition revealed a distinct separation within the genus. The strain grows between 26-45°C and forms biofilms equivalent to L. pneumophila Philadelphia 1. These characteristics suggest that this isolate is a novel Legionella species, for which the name Legionella clemsonensis sp nov. is proposed.

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Legioliulin, a new isocoumarin compound responsible for blue-white autofluorescence in Legionella (Fluoribacter) dumoffii under long-wavelength UV light

Cited by 30 publications

References 31 publications

Synthesis and photophysical properties of isocoumarin-based D-π-A systems

Synthesis and photophysical properties of isocoumarin-based D-π-A systems

Autofluorescence of Mycobacteria as a Tool for Detection of Mycobacterium tuberculosis

Legionella clemsonensis sp. nov.: a green fluorescing Legionella strain from a patient with pneumonia

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