scholarly journals Red fluorescence increases with depth in reef fishes, supporting a visual function, not UV protection

2014 ◽  
Vol 281 (1790) ◽  
pp. 20141211 ◽  
Author(s):  
Melissa G. Meadows ◽  
Nils Anthes ◽  
Sandra Dangelmayer ◽  
Magdy A. Alwany ◽  
Tobias Gerlach ◽  
...  
Keyword(s):  
Light Emission ◽  
Reef Fishes ◽  
Marine Fishes ◽  
Fluorescent Light ◽  
Red Fluorescence ◽  
Visual Contrast ◽  
Uv Irradiance ◽  
Reef Fish Species ◽  
Nm Range

Why do some marine fishes exhibit striking patterns of natural red fluorescence? In this study, we contrast two non-exclusive hypotheses: (i) that UV absorption by fluorescent pigments offers significant photoprotection in shallow water, where UV irradiance is strongest; and (ii) that red fluorescence enhances visual contrast at depths below −10 m, where most light in the ‘red’ 600–700 nm range has been absorbed. Whereas the photoprotection hypothesis predicts fluorescence to be stronger near the surface and weaker in deeper water, the visual contrast hypothesis predicts the opposite. We used fluorometry to measure red fluorescence brightness in vivo in individuals belonging to eight common small reef fish species with conspicuously red fluorescent eyes. Fluorescence was significantly brighter in specimens from the −20 m sites than in those from −5 m sites in six out of eight species. No difference was found in the remaining two. Our results support the visual contrast hypothesis. We discuss the possible roles fluorescence may play in fish visual ecology and highlight the possibility that fluorescent light emission from the eyes in particular may be used to detect cryptic prey.

scholarly journals Does red eye fluorescence in marine fish stand out? In situ and in vivo measurements at two depths

2017 ◽  
Author(s):  
U. K. Harant ◽  
F. Wehrberger ◽  
T. Griessler ◽  
M. G. Meadows ◽  
C. M. Champ ◽  
...  
Keyword(s):  
Natural Light ◽  
Potential Contribution ◽  
Red Fluorescence ◽  
Visual Contrast ◽  
Wide Range ◽  
Negative Effect ◽  
Nm Range ◽  
Visual Brightness

AbstractSince the discovery of red fluorescence in fish, much effort has been made to elucidate its potential contribution to vision. However, whatever that function might be, it always implies that the combination of red fluorescence and reflectance of the red iris is sufficient to generate a visual contrast. Here, we present in vivo iris radiance measurements of T. delaisi under natural light fields at 5 and 20 m depth. We also took substrate radiance measurements of shaded and exposed foraging sites at those depths. To assess the visual contrast that can be generated by the red iris, we then calculated iris brightness in the 600-650 nm “red” waveband relative to substrate radiance. At 20 m depth, T. delaisi iris radiance substantially exceeded substrate radiance in the red waveband, regardless of exposure, and despite substrate fluorescence. Given that downwelling light in the 600-650 nm range is negligible at this depth, we can attribute this effect to iris fluorescence. As expected, contrasts were much weaker in 5 m – despite the added contribution of iris reflectance, but we identified specific substrates and conditions under which the pooled radiance caused by red reflectance and fluorescence still exceeded substrate radiance in the same waveband. Due to the negative effect of anesthesia on iris fluorescence these estimates are conservative. We conclude that the requirements to create visual brightness contrasts are fulfilled for a wide range of conditions in the natural environment of T. delaisi.

In vivo visualization of oxidative changes in microvessels during neutrophil activation

1993 ◽  
Vol 264 (3) ◽  
pp. H881-H891 ◽  
Author(s):  
M. Suematsu ◽  
G. W. Schmid-Schonbein ◽  
R. H. Chavez-Chavez ◽  
T. T. Yee ◽  
T. Tamatani ◽  
...  
Keyword(s):  
Light Emission ◽  
Platelet Activating Factor ◽  
Fluorescent Light ◽  
Radical Scavenger ◽  
Neutrophil Adhesion ◽  
Light Sources ◽  
Microvascular Endothelium ◽  
Rat Mesentery ◽  
Venular Endothelium

This study was designed to characterize temporal changes of oxidative metabolism in microvascular endothelium in vivo associated with neutrophil adhesion and diapedesis. The rat mesentery was loaded with dichlorofluorescein (DCFH) diacetate, a hydroperoxide-sensitive fluorescent probe that is trapped within viable cells as a nonfluorescent form and is converted to fluorescent dichlorofluorescein (DCF) by hydroperoxides. The fluorescent light emission was recorded with digital microscopy and its camera response was calibrated by superfusion of the mesentery with known concentrations of hydroperoxides. After rinsing with a precursor-free solution, it was possible to observe both the neutrophil adhesion and fluorescence changes in venular endothelium during superfusion with platelet-activating factor (PAF, 100 nM) by alternately changing light sources. In the PAF-treated animals, DCF fluorescence in the venular wall was markedly elevated concurrent with an increase in the number of adherent neutrophils. An onset of a significant DCF fluorescence was observed as early as 10 min after PAF application. The venular oxidative changes were co-localized with neutrophils adhering to the endothelium or migrating into the interstitium. The oxidative impact in the venular wall superfused with 100 nM PAF for 40 min was equivalent to that induced by the 10-min superfusion of 0.8 mM of tert-butyl hydroperoxide. Pretreatment with dipyridyl, an iron chelator, or dimethylthiourea, a hydroxyl radical scavenger, significantly attenuated the PAF-induced oxidative changes in the venule but had little effect on neutrophil adhesion. These findings suggest that an endothelial cell-dependent mechanism involving an iron-catalyzed reaction may have a role in enhancement of neutrophil-mediated oxidative stress in venular endothelium.

scholarly journals Fluorescent, Prussian Blue-Based Biocompatible Nanoparticle System for Multimodal Imaging Contrast

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1732
Author(s):  
László Forgách ◽  
Nikolett Hegedűs ◽  
Ildikó Horváth ◽  
Bálint Kiss ◽  
Noémi Kovács ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Prussian Blue ◽  
Fluorescent Dyes ◽  
Light Emission ◽  
Fluorescent Dye ◽  
Fluorescent Imaging ◽  
Fluorescent Light ◽  
Eosin Y ◽  
Biodistribution Studies

(1) Background. The main goal of this work was to develop a fluorescent dye-labelling technique for our previously described nanosized platform, citrate-coated Prussian blue (PB) nanoparticles (PBNPs). In addition, characteristics and stability of the PB nanoparticles labelled with fluorescent dyes were determined. (2) Methods. We adsorbed the fluorescent dyes Eosin Y and Rhodamine B and methylene blue (MB) to PB-nanoparticle systems. The physicochemical properties of these fluorescent dye-labeled PBNPs (iron(II);iron(III);octadecacyanide) were determined using atomic force microscopy, dynamic light scattering, zeta potential measurements, scanning- and transmission electron microscopy, X-ray diffraction, and Fourier-transformation infrared spectroscopy. A methylene-blue (MB) labelled, polyethylene-glycol stabilized PBNP platform was selected for further assessment of in vivo distribution and fluorescent imaging after intravenous administration in mice. (3) Results. The MB-labelled particles emitted a strong fluorescent signal at 662 nm. We found that the fluorescent light emission and steric stabilization made this PBNP-MB particle platform applicable for in vivo optical imaging. (4) Conclusion. We successfully produced a fluorescent and stable, Prussian blue-based nanosystem. The particles can be used as a platform for imaging contrast enhancement. In vivo stability and biodistribution studies revealed new aspects of the use of PBNPs.

scholarly journals The Design and Preclinical Evaluation of a Single-Label Bimodal Nanobody Tracer for Image-Guided Surgery

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 360
Author(s):  
Pieterjan Debie ◽  
Noemi B. Declerck ◽  
Danny van Willigen ◽  
Celine M. Huygen ◽  
Bieke De Sloovere ◽  
...  
Keyword(s):  
Single Molecule ◽  
Gamma Ray ◽  
Nuclear Imaging ◽  
Primary Amines ◽  
Resection Margins ◽  
Fluorescent Light ◽  
Single Structure ◽  
Fluorescence Images

Intraoperative guidance using targeted fluorescent tracers can potentially provide surgeons with real-time feedback on the presence of tumor tissue in resection margins. To overcome the limited depth penetration of fluorescent light, combining fluorescence with SPECT/CT imaging and/or gamma-ray tracing has been proposed. Here, we describe the design and preclinical validation of a novel bimodal nanobody-tracer, labeled using a “multifunctional single attachment point” (MSAP) label, integrating a Cy5 fluorophore and a diethylenetriaminepentaacetic acid (DTPA) chelator into a single structure. After conjugation of the bimodal MSAP to primary amines of the anti-HER2 nanobody 2Rs15d and 111In-labeling of DTPA, the tracer’s characteristics were evaluated in vitro. Subsequently, its biodistribution and tumor targeting were assessed by SPECT/CT and fluorescence imaging over 24 h. Finally, the tracer’s ability to identify small, disseminated tumor lesions was investigated in mice bearing HER2-overexpressing SKOV3.IP1 peritoneal lesions. [111In]In-MSAP.2Rs15d retained its affinity following conjugation and remained stable for 24 h. In vivo SPECT/CT and fluorescence images showed specific uptake in HER2-overexpressing tumors with low background. High tumor-to-muscle ratios were obtained at 1h p.i. and remained 19-fold on SPECT/CT and 3-fold on fluorescence images over 24 h. In the intraperitoneally disseminated model, the tracer allowed detection of larger lesions via nuclear imaging, while fluorescence enabled accurate removal of submillimeter lesions. Bimodal nuclear/fluorescent nanobody-tracers can thus be conveniently designed by conjugation of a single-molecule MSAP-reagent carrying a fluorophore and chelator for radioactive labeling. Such tracers hold promise for clinical applications.

scholarly journals In VivoandIn VitroEfficacy of Chloroquine againstPlasmodium malariaeandP. ovalein Papua, Indonesia

2010 ◽  
Vol 55 (1) ◽  
pp. 197-202 ◽  
Author(s):  
H. Siswantoro ◽  
B. Russell ◽  
A. Ratcliff ◽  
B. Prasetyorini ◽  
F. Chalfein ◽  
...  
Keyword(s):  
Parasite Clearance ◽  
Plasmodium Malariae ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Chloroquine Resistance ◽  
Ring Stage ◽  
Trophozoite Stage ◽  
Nm Range

ABSTRACTReports of potential drug-resistant strains ofPlasmodium malariaein western Indonesia raise concerns that chloroquine resistance may be emerging inP. malariaeandP. ovale. In order to assess this,in vivoandin vitroefficacy studies were conducted in patients with monoinfection in Papua, Indonesia. Consecutive patients with uncomplicated malaria due toP. ovaleorP. malariaewere enrolled in a prospective clinical trial, provided with supervised chloroquine treatment, and followed for 28 days. Blood from patients withP. malariaeorP. ovaleparasitemia greater than 1,000 per microliter underwentin vitroantimalarial drug susceptibility testing using a modified schizont maturation assay. Of the 57 evaluable patients in the clinical study (P. malariae,n= 46;P. ovale,n= 11), none had recurrence with the same species during follow-up. The mean parasite reduction ratio at 48 h was 86 (95% confidence interval [CI], 57 to 114) forP. malariaeand 150 (95% CI, 54 to 245) forP. ovale(P= 0.18). One patient infected withP. malariae, with 93% of parasites at the trophozoite stage, was still parasitemic on day 4.In vitrodrug susceptibility assays were carried out successfully for 40 isolates (34 infected withP. malariaeand 6 withP. ovale). TheP. malariaeinfections at trophozoite stages had significantly higher chloroquine 50% effective concentrations (EC50s) (median, 127.9 nM [range, 7.9 to 2,980]) than those initially exposed at the ring stage (median, 14.0 nM [range, 3.5 to 27.0];P= 0.01). The EC50for chloroquine inP. ovalewas also higher in an isolate initially at the trophozoite stage (23.2 nM) than in the three isolates predominantly at ring stage (7.8 nM). Chloroquine retains adequate efficacy againstP. ovaleandP. malariae, but its marked stage specificity of action may account for reports of delayed parasite clearance times.

scholarly journals In Vivo Bioluminescence Imaging for the Study of Intestinal Colonization by Escherichia coli in Mice

2009 ◽  
Vol 76 (1) ◽  
pp. 264-274 ◽  
Author(s):  
M.-L. Foucault ◽  
L. Thomas ◽  
S. Goussard ◽  
B. R. Branchini ◽  
C. Grillot-Courvalin
Keyword(s):  
Escherichia Coli ◽  
Bioluminescence Imaging ◽  
Light Emission ◽  
Direct Method ◽  
Firefly Luciferase ◽  
Intestinal Colonization ◽  
Bacterial Populations ◽  
Bioluminescence Signal

ABSTRACT Bioluminescence imaging (BLI) is emerging as a powerful tool for real-time monitoring of infections in living animals. However, since luciferases are oxygenases, it has been suggested that the requirement for oxygen may limit the use of BLI in anaerobic environments, such as the lumen of the gut. Strains of Escherichia coli harboring the genes for either the bacterial luciferase from Photorhabdus luminescens or the PpyRE-TS and PpyGR-TS firefly luciferase mutants of Photinus pyralis (red and green thermostable P. pyralis luciferase mutants, respectively) have been engineered and used to monitor intestinal colonization in the streptomycin-treated mouse model. There was excellent correlation between the bioluminescence signal measured in the feces (R 2 = 0.98) or transcutaneously in the abdominal region of whole animals (R 2 = 0.99) and the CFU counts in the feces of bacteria harboring the luxABCDE operon. Stability in vivo of the bioluminescence signal was achieved by constructing plasmid pAT881(pGB2ΩPamiluxABCDE), which allowed long-term monitoring of intestinal colonization without the need for antibiotic selection for plasmid maintenance. Levels of intestinal colonization by various strains of E. coli could be compared directly by simple recording of the bioluminescence signal in living animals. The difference in spectra of light emission of the PpyRE-TS and PpyGR-TS firefly luciferase mutants and dual bioluminescence detection allowed direct in vitro and in vivo quantification of two bacterial populations by measurement of red and green emitted signals and thus monitoring of the two populations simultaneously. This system offers a simple and direct method to study in vitro and in vivo competition between mutants and the parental strain. BLI is a useful tool to study intestinal colonization.

scholarly journals Rational Design of a Triple Reporter Gene for Multimodality Molecular Imaging

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Ya-Ju Hsieh ◽  
Luen Hwu ◽  
Chien-Chih Ke ◽  
Skye Hsin-Hsien Yeh ◽  
Chien-Feng Lin ◽  
...  
Keyword(s):  
Reporter Gene ◽  
Rational Design ◽  
Multimodality Imaging ◽  
Firefly Luciferase ◽  
Luciferase Reporter ◽  
Fluorescence Signal ◽  
Red Fluorescence ◽  
Simplex Virus

Multimodality imaging using noncytotoxic triple fusion (TF) reporter genes is an important application for cell-based tracking, drug screening, and therapy. The firefly luciferase(fl), monomeric red fluorescence protein(mrfp), and truncated herpes simplex virus type 1 thymidine kinase SR39 mutant(ttksr39)were fused together to create TF reporter gene constructs with different order. The enzymatic activities of TF protein in vitro andin vivowere determined by luciferase reporter assay,H-FEAU cellular uptake experiment, bioluminescence imaging, and micropositron emission tomography (microPET). The TF construct expressed in H1299 cells possesses luciferase activity and red fluorescence. The tTKSR39 activity is preserved in TF protein and mediates high levels ofH-FEAU accumulation and significant cell death from ganciclovir (GCV) prodrug activation. In living animals, the luciferase and tTKSR39 activities of TF protein have also been successfully validated by multimodality imaging systems. The red fluorescence signal is relatively weak forin vivoimaging but may expedite FACS-based selection of TF reporter expressing cells. We have developed an optimized triple fusion reporter constructDsRedm-fl-ttksr39for more effective and sensitivein vivoanimal imaging using fluorescence, bioluminescence, and PET imaging modalities, which may facilitate different fields of biomedical research and applications.

scholarly journals DNA-based identification of predators of the corallivorous Crown-of-Thorns Starfish (Acanthaster cf. solaris) from fish faeces and gut contents

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Frederieke J. Kroon ◽  
Carine D. Lefèvre ◽  
Jason R. Doyle ◽  
Frances Patel ◽  
Grant Milton ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Fish Species ◽  
Coral Reef Fish ◽  
Coral Cover ◽  
Fish Predation ◽  
Reef Fishes ◽  
Positive Control ◽  
Gut Contents ◽  
Reef Fish Species

Abstract The corallivorous Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) has been linked with the widespread loss of scleractinian coral cover on Indo-Pacific reefs during periodic population outbreaks. Here, we re-examine CoTS consumption by coral reef fish species by using new DNA technologies to detect Pacific Crown-of-Thorns Starfish (Acanthaster cf. solaris) in fish faecal and gut content samples. CoTS DNA was detected in samples from 18 different coral reef fish species collected on reefs at various stages of CoTS outbreaks in the Great Barrier Reef Marine Park, nine of which had not been previously reported to feed on CoTS. A comprehensive set of negative and positive control samples confirmed that our collection, processing and analysis procedures were robust, although food web transfer of CoTS DNA cannot be ruled out for some fish species. Our results, combined with the (i) presence of CoTS spines in some samples, (ii) reported predation on CoTS gametes, larvae and settled individuals, and (iii) known diet information for fish species examined, strongly indicate that direct fish predation on CoTS may well be more common than is currently appreciated. We provide recommendations for specific management approaches to enhance predation on CoTS by coral reef fishes, and to support the mitigation of CoTS outbreaks and reverse declines in hard coral cover.

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