Spectral microscopic imaging of heterocysts and vegetative cells in two filamentous cyanobacteria based on spontaneous Raman scattering and photoluminescence by 976 nm excitation

Tamamizu, Kouto; Kumazaki, Shigeichi

doi:10.1016/j.bbabio.2018.11.012

Cited by 12 publications

(20 citation statements)

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“…Furthermore, the excitation wavelengths of most porphyrins are in the blue light range, which may cause tissue damage. Thus, efforts are underway to create porphyrins with excitation wavelengths in the infrared range to overcome this obstacle [50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

2020

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One of the greatest threats to human health is the rise in antibiotic-resistant bacterial infections. Pseudomonas aeruginosa (PsA) is an “opportunistic” pathogen known to cause life-threatening infections in immunocompromised individuals and is the most common pathogen in adults with cystic fibrosis (CF). We report here a cationic zinc (II) porphyrin, ZnPor, that effectively kills planktonic and biofilm-associated cells of PsA. In standard tests against 16–18 h-old biofilms, concentrations as low as 16 µg/mL resulted in the extensive disruption and detachment of the matrix. The pre-treatment of biofilms for 30 min with ZnPor at minimum inhibitory concentration (MIC) levels (4 µg/mL) substantially enhanced the ability of tobramycin (Tobra) to kill biofilm-associated cells. We demonstrate the rapid uptake and accumulation of ZnPor in planktonic cells even in dedicated heme-uptake system mutants (ΔPhu, ΔHas, and the double mutant). Furthermore, uptake was unaffected by the ionophore carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Cells pre-exposed to ZnPor took up the cell-impermeant dye SYTOXTM Green in a concentration-dependent manner. The accumulation of ZnPor did not result in cell lysis, nor did the cells develop resistance. Taken together, these properties make ZnPor a promising candidate for treating multi-drug-resistant infections, including persistent, antibiotic-resistant biofilms.

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Section: Introductionmentioning

confidence: 99%

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

2020

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“…Secretions of scytonemins may be coordinated with that of extracellular polysaccharides partly through closeness between their secretion sites. Substantial decrease in the ratio of phycobilin/carotenoid compared to that of vegetative cells is a typical feature of matured heterocysts including those of Rivularia M-261 22,23 . This reflects the decrease of light-harvesting phycobilisomes (binding phycobilins) and PSII (binding carotenoids) for the anaerobic conditions required for the heterocysts, which results in no fixation of carbons in mature heterocysts 31 .…”

Section: Discussionmentioning

confidence: 99%

“…The matured heterocysts in the filaments without dark sheaths of Rivularia M-261 (as [w/o DS, no UVA]) have been reported to show lower phycobilin/carotenoid ratios than the nearby vegetative cells (Fig. 2b) 23 . However, the filaments of the [w/ ReDS, no UVA] type tended not to show a decrease of phycobilins/carotenoids ratio in their heterocysts (Table 1, Fig.…”

Section: Cellular Differentiation and Scytonemin Redox Conditionsmentioning

confidence: 99%

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Sunscreen redox status in a multicellular cyanobacterium visualized by Raman scattering spectral microscope

Tamamizu

Sakamoto

Kurashige

et al. 2022

Preprint

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UV radiation, desiccation, and starvation induce some cyanobacteria to produce a UVA-absorbing pigment, scytonemin, at extracellular sheaths. Although the accumulation of scytonemin is recognizable as dark sheaths through optical microscopes, it has been nontrivial to identify its redox status and obtain its subcellular distribution in response to physiological conditions. Here, we show that a spontaneous Raman scattering spectral microscopy based on an excitation-laser-line-scanning method unveil 3D subcellular distributions of non-UV-induced scytonemins with distinct redox statuses in a filamentous cyanobacterium with a single nitrogen-fixing cell at the basal end. Cellular differentiations and scytonemin redox conditions were simultaneously visualized with an excitation wavelength at 1064 nm that is virtually free from the optical screening by the dark sheaths. The molecular imaging results give insights into not only secretion mechanisms of the sunscreen pigment but also interdependence between photosynthesis, nitrogen fixation, and redox homeostasis in one of the simplest forms of multicellular organisms.

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“…It is worth noting that there were strong fluorescent backgrounds, which tended to increase with the increase of wave number. These fluorescent backgrounds may be caused by chromophores (pigment) in plant tissues [21,46]. WT treatment was carried out to eliminate the fluorescence background, and reconstructed spectral information based on D6 is shown in Fig.…”

Section: Raman Spectral Unsupervised Clustering Of Rice Straw Before mentioning

confidence: 99%

Quantitative visualization of subcellular lignocellulose revealing the mechanism of alkali pretreatment to promote methane production of rice straw

Sha

Xia

et al. 2020

Biotechnol Biofuels

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Background: As a renewable carbon source, biomass energy not only helps in resolving the management problems of lignocellulosic wastes, but also helps to alleviate the global climate change by controlling environmental pollution raised by their generation on a large scale. However, the bottleneck problem of extensive production of biofuels lies in the filamentous crystal structure of cellulose and the embedded connection with lignin in biomass that leads to poor accessibility, weak degradation and digestion by microorganisms. Some pretreatment methods have shown significant improvement of methane yield and production rate, but the promotion mechanism has not been thoroughly studied. Revealing the temporal and spatial effects of pretreatment on lignocellulose will greatly help deepen our understanding of the optimization mechanism of pretreatment, and promote efficient utilization of lignocellulosic biomass. Here, we propose an approach for qualitative, quantitative, and location analysis of subcellular lignocellulosic changes induced by alkali treatment based on label-free Raman microspectroscopy combined with chemometrics. Results: Firstly, the variations of rice straw induced by alkali treatment were characterized by the Raman spectra, and the Raman fingerprint characteristics for classification of rice straw were captured. Then, a label-free Raman chemical imaging strategy was executed to obtain subcellular distribution of the lignocellulose, in the strategy a serious interference of plant tissues' fluorescence background was effectively removed. Finally, the effects of alkali pretreatment on the subcellular spatial distribution of lignocellulose in different types of cells were discovered. Conclusions: The results demonstrated the mechanism of alkali treatment that promotes methane production in rice straw through anaerobic digestion by means of a systemic study of the evidence from the macroscopic measurement and Raman microscopic quantitative and localization two-angle views. Raman chemical imaging combined with chemometrics could nondestructively realize qualitative, quantitative, and location analysis of the lignocellulose of rice straw at a subcellular level in a label-free way, which was beneficial to optimize pretreatment for the improvement of biomass conversion efficiency and promote extensive utilization of biofuel.

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Spectral microscopic imaging of heterocysts and vegetative cells in two filamentous cyanobacteria based on spontaneous Raman scattering and photoluminescence by 976 nm excitation

Cited by 12 publications

References 71 publications

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

Sunscreen redox status in a multicellular cyanobacterium visualized by Raman scattering spectral microscope

Quantitative visualization of subcellular lignocellulose revealing the mechanism of alkali pretreatment to promote methane production of rice straw

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Spectral microscopic imaging of heterocysts and vegetative cells in two filamentous cyanobacteria based on spontaneous Raman scattering and photoluminescence by 976 nm excitation

Cited by 12 publications

References 71 publications

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

Sunscreen redox status in a multicellular cyanobacterium visualized by Raman scattering spectral microscope

Quantitative visualization of subcellular lignocellulose revealing the mechanism of alkali pretreatment to promote methane production of rice straw

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Spectral microscopic imaging of heterocysts and vegetative cells in two filamentous cyanobacteria based on spontaneous Raman scattering and photoluminescence by 976 nm excitation