scholarly journals Taxon- and senescence-specific fluorescence of colored leaves from the Pliocene Willershausen Lagerstätte, Germany

PalZ ◽  
2021 ◽  
Author(s):  
Klaus Wolkenstein ◽  
Gernot Arp
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Degradation Products ◽  
Emission Spectra ◽  
Plant Macrofossils ◽  
Laser Scanning Microscopy ◽  
Fluorescence Properties ◽  
Confocal Laser ◽  
Lower Saxony ◽  
Coal Macerals

AbstractUV-light-induced fluorescence is widely used in the study of coal macerals and palynological samples, but to date has not been described in great detail for plant macrofossils. Here, we report the characteristics of bright UV-light-induced fluorescence of various fossil angiosperm leaf taxa from the Upper Pliocene of Willershausen, Lower Saxony, Germany. The fluorescence is exceptional, since different fluorescence colors ranging from green to yellow to red can be observed and fluorescence properties are found to be related to genera. Using confocal laser scanning microscopy, fluorescence was studied in detail and emission spectra were obtained that allowed to differentiate broad groups of fluorophores. Fluorescence emissions attributed to chlorophyll degradation products demonstrate that fluorescence can be used as an indicator for exceptional chemical preservation of leaf fossils. Comparison with present-day senescing plants suggests that the fluorescence differences in the fossil leaves are mainly caused by taxon-specific degeneration of organic compounds during senescence. The occurrence of various leaf taxa with different fluorescence properties, preserved under identical conditions of fossilization, indicate that diagenesis was not crucial for the differences in leaf fluorescence.

scholarly journals Environment-Sensitive Fluorescent Labelling of Peptides by Luciferin Analogues

2021 ◽  
Vol 22 (24) ◽  
pp. 13312
Author(s):  
Marialuisa Siepi ◽  
Rosario Oliva ◽  
Antonio Masino ◽  
Rosa Gaglione ◽  
Angela Arciello ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Emission Spectra ◽  
Water Concentration ◽  
Solvent Polarity ◽  
Firefly Luciferase ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Water Abundance ◽  
Proteins And Peptides

Environment-sensitive fluorophores are very valuable tools in the study of molecular and cellular processes. When used to label proteins and peptides, they allow for the monitoring of even small variations in the local microenvironment, thus acting as reporters of conformational variations and binding events. Luciferin and aminoluciferin, well known substrates of firefly luciferase, are environment-sensitive fluorophores with unusual and still-unexploited properties. Both fluorophores show strong solvatochromism. Moreover, luciferin fluorescence is influenced by pH and water abundance. These features allow to detect local variations of pH, solvent polarity and local water concentration, even when they occur simultaneously, by analyzing excitation and emission spectra. Here, we describe the characterization of (amino)luciferin-labeled derivatives of four bioactive peptides: the antimicrobial peptides GKY20 and ApoBL, the antitumor peptide p53pAnt and the integrin-binding peptide RGD. The two probes allowed for the study of the interaction of the peptides with model membranes, SDS micelles, lipopolysaccharide micelles and Escherichia coli cells. Kd values and binding stoichiometries for lipopolysaccharide were also determined. Aminoluciferin also proved to be very well-suited to confocal laser scanning microscopy. Overall, the characterization of the labeled peptides demonstrates that luciferin and aminoluciferin are previously neglected environment-sensitive labels with widespread potential applications in the study of proteins and peptides.

scholarly journals Ultraviolet Light Induces Apoptosis via Direct Activation of CD95 (Fas/APO-1) Independently of Its Ligand CD95L

1998 ◽  
Vol 140 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Yoshinori Aragane ◽  
Dagmar Kulms ◽  
Dieter Metze ◽  
Gabriele Wilkes ◽  
Birgit Pöppelmann ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Critical Event ◽  
Hacat Cells ◽  
Death Domain ◽  
Natural Ligand ◽  
Keratinocyte Cell Line Hacat ◽  
Induced Apoptosis

Induction of apoptosis in keratinocytes by UV light is a critical event in photocarcinogenesis. Although p53 is of importance in this process, evidence exists that other pathways play a role as well. Therefore, we studied whether the apoptosis-related surface molecule CD95 (Fas/APO-1) is involved. The human keratinocyte cell line HaCaT expresses CD95 and undergoes apoptosis after treatment with UV light or with the ligand of CD95 (CD95L). Incubation with a neutralizing CD95 antibody completely prevented CD95L-induced apoptosis but not UV-induced apoptosis, initially suggesting that the CD95 pathway may not be involved. However, the protease CPP32, a downstream molecule of the CD95 pathway, was activated in UV-exposed HaCaT cells, and UV-induced apoptosis was blocked by the ICE protease inhibitor zVAD, implying that at least similar downstream events are involved in CD95- and UV-induced apoptosis. Activation of CD95 results in recruitment of the Fas-associated protein with death domain (FADD) that activates ICE proteases. Immunoprecipitation of UV-exposed HaCaT cells revealed that UV light also induces recruitment of FADD to CD95. Since neutralizing anti-CD95 antibodies failed to prevent UV-induced apoptosis, this suggested that UV light directly activates CD95 independently of the ligand CD95L. Confocal laser scanning microscopy showed that UV light induced clustering of CD95 in the same fashion as CD95L. Prevention of UV-induced CD95 clustering by irradiating cells at 10°C was associated with a significantly reduced death rate. Together, these data indicate that UV light directly stimulates CD95 and thereby activates the CD95 pathway to induce apoptosis independently of the natural ligand CD95L. These findings further support the concept that UV light can affect targets at the plasma membrane, thereby even inducing apoptosis.

Detecting exodermal Casparian bands in vivo and fluid-phase endocytosis in onion (Allium cepa L.) roots

2001 ◽  
Vol 79 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Ewa Cholewa ◽  
Carol A Peterson
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Fluid Phase ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Running Water ◽  
Casparian Bands ◽  
Fluid Phase Endocytosis ◽  
Casparian Band

Maturation of the exodermis involves development of a Casparian band, a structure that blocks the apoplastic movement of ions. The position at which this band is formed is not readily predictable, since it depends on species and growing conditions. Until now, Casparian band detection necessitated destructive methods which involved sectioning or clearing the roots. In the present study, a method for detecting exodermal Casparian bands in vivo is presented. Undisturbed onion roots were incubated for 2 h in 0.1% 8-hydroxy-1,3,6-pyrenetrisulphonate (PTS) and then thoroughly rinsed in running water. Under UV light, the tracer was evident in the cortex of the root regions with an immature exodermis but not in older regions of the root where the Casparian band had developed. PTS had entered the protoplasts of the cortical cells in the younger part of the root and had not been removed by rinsing. The first order kinetics of uptake, and insensitivity to external pH and probenecid indicated that PTS entered the cell by fluid-phase endocytosis. PTS-loaded vesicles that released their contents into the vacuole were seen using confocal laser scanning microscopy. When applied to undisturbed, whole root systems, PTS was not detected in aqueous extracts of the leaves. Thus, there is no major apoplastic bypass in healthy onion roots.Key words: exodermis, Casparian bands, apoplastic bypass, PTS, fluid-phase endocytosis.

scholarly journals UV Treatment of the Stabilizing Shell for Improving the Photostability of Silver Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Silvia Rinaldi ◽  
Luigi Tarpani ◽  
Loredana Latterini
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Laser Scanning ◽  
Prolonged Exposure ◽  
Uv Light ◽  
Light Exposure ◽  
Uv Curing ◽  
Laser Scanning Microscopy ◽  
Localized Surface Plasmon ◽  
Confocal Laser

Silver nanoparticles or nanoclusters are quite sensitive to light exposure. In particular, irradiation in the localized surface plasmon resonance (LSPR) region brings about a drastic modification of their optical properties due to growth and reshaping of the nanoparticles. In order to obtain luminescent colloids, small silver colloidal nanoparticles were prepared in chloroform using vinylpyrrolidone oligomers as capping agent and their luminescence properties were used to control their stability upon prolonged exposure to visible light. The polymeric shell around the metal clusters was hardened through photo-cross-linking by UV light. This process did not alter the morphology and the optical properties of the nanoparticles but greatly improved the particle photostability as confirmed also by confocal laser scanning microscopy measurements. The data clearly show that UV curing of the stabilizing layer could be a simple postsynthetic procedure to obtain materials with stable properties.

scholarly journals Ceraphron krogmanni (Hymenoptera: Ceraphronidae), a new species from Lower Saxony with unusual male genitalia

2018 ◽  
Vol 6 ◽  
pp. e24173
Author(s):  
Jonah Ulmer ◽  
Istvan Miko ◽  
Andrew Deans
Keyword(s):  
Male Genitalia ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Lower Saxony ◽  
Anatomical Structures ◽  
Recent Developments ◽  
Character Set ◽  
Field Imaging ◽  
A New Species

Male genitalia phenotypes of Ceraphron (Jurine, 1807) are informative for species delimitation, but due to their minute size, these characters have not been used extensively. Recent developments in visualisation techniques, e.g. confocal laser scanning microscopy and high resolution bright field imaging, allow for more thorough examination of these minute anatomical structures and the development of a robust, male genitalia-based taxonomic system. We also establish a character set, a template, that will facilitate future revisions of these wasps. Ceraphronkrogmanni sp. nov. is described with outsized male genitalia and multiple diagnostic traits that are unique amongst Ceraphron species.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

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