scholarly journals SparkMaster: automated calcium spark analysis with ImageJ

2007 ◽  
Vol 293 (3) ◽  
pp. C1073-C1081 ◽  
Author(s):  
Eckard Picht ◽  
Aleksey V. Zima ◽  
Lothar A. Blatter ◽  
Donald M. Bers
Keyword(s):  
Laser Scanning ◽  
Low Frequency ◽  
Maximum Amplitude ◽  
High Sensitivity ◽  
Automated Analysis ◽  
Confocal Laser ◽  
Mammalian Skeletal Muscle ◽  
Full Width ◽  
Half Maximum ◽  
Experimental Conditions

Ca sparks are elementary Ca-release events from intracellular Ca stores that are observed in virtually all types of muscle. Typically, Ca sparks are measured in the line-scan mode with confocal laser-scanning microscopes, yielding two-dimensional images (distance vs. time). The manual analysis of these images is time consuming and prone to errors as well as investigator bias. Therefore, we developed SparkMaster, an automated analysis program that allows rapid and reliable spark analysis. The underlying analysis algorithm is adapted from the threshold-based standard method of spark analysis developed by Cheng et al. ( Biophys J 76: 606–617, 1999) and is implemented here in the freely available image-processing software ImageJ. SparkMaster offers a graphical user interface through which all analysis parameters and output options are selected. The analysis includes general image parameters (number of detected sparks, spark frequency) and individual spark parameters (amplitude, full width at half-maximum amplitude, full duration at half-maximum amplitude, full width, full duration, time to peak, maximum steepness of spark upstroke, time constant of spark decay). We validated the algorithm using images with synthetic sparks embedded into backgrounds with different signal-to-noise ratios to determine an analysis criteria at which a high sensitivity is combined with a low frequency of false-positive detections. Finally, we applied SparkMaster to analyze experimental data of sparks measured in intact and permeabilized ventricular cardiomyocytes, permeabilized mammalian skeletal muscle, and intact smooth muscle cells. We found that SparkMaster provides a reliable, easy to use, and fast way of analyzing Ca sparks in a wide variety of experimental conditions.

scholarly journals Molecular identification of fungi microfossils in a Neoproterozoic shale rock

2020 ◽  
Vol 6 (4) ◽  
pp. eaax7599 ◽  
Author(s):  
S. Bonneville ◽  
F. Delpomdor ◽  
A. Préat ◽  
C. Chevalier ◽  
T. Araki ◽  
...  
Keyword(s):  
Land Surface ◽  
Laser Scanning ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Low Frequency ◽  
Confocal Laser ◽  
Spectroscopic Techniques ◽  
High Angle ◽  
Identification Of Fungi ◽  
Colonization Of Land

Precambrian fossils of fungi are sparse, and the knowledge of their early evolution and the role they played in the colonization of land surface are limited. Here, we report the discovery of fungi fossils in a 810 to 715 million year old dolomitic shale from the Mbuji-Mayi Supergroup, Democratic Republic of Congo. Syngenetically preserved in a transitional, subaerially exposed paleoenvironment, these carbonaceous filaments of ~5 μm in width exhibit low-frequency septation (pseudosepta) and high-angle branching that can form dense interconnected mycelium-like structures. Using an array of microscopic (SEM, TEM, and confocal laser scanning fluorescence microscopy) and spectroscopic techniques (Raman, FTIR, and XANES), we demonstrated the presence of vestigial chitin in these fossil filaments and document the eukaryotic nature of their precursor. Based on those combined evidences, these fossil filaments and mycelium-like structures are identified as remnants of fungal networks and represent the oldest, molecularly identified remains of Fungi.

scholarly journals On the Expansion of Space and How to Measure It

2018 ◽  
Author(s):  
Firmin J. Oliveira
Keyword(s):  
Storage Time ◽  
Laser Interferometer ◽  
Hubble Constant ◽  
High Sensitivity ◽  
Full Width ◽  
Half Maximum ◽  
Light Storage ◽  
Proportionality Constant ◽  
Long Period ◽  
Expansion Of Space

We describe the effect of the expansion of space on the wavelength of the light beam in a Fabry-Pérot interferometer. For an instrument such as the Laser Interferometer Gravitational-Wave Observatory (LIGO), which has high sensitivity and a long period of light storage, the wavelength λ L of laser photons are redshifted due to the expansion of space in each cavity by an amount δ λ given by δ λ / λ L = H 0 τ s ≈ 8 . 8 × 10 - 21 , where H 0 ≈ 2 . 2 × 10 - 18 s - 1 is the Hubble constant and τ s ≈ 4 ms is the light storage time for the cavity. Since τ s is based on the cavity finesse F which depends on the laser beam full width at half maximum (FWHM) δ ω of each cavity, we show that a difference in finesses between the LIGO arm cavities produces a signal h H ( t ) at the anti-symmetric output port given by h H t = 2 a 1 H 0 1 δ ω X t - 1 δ ω Y t , where δ ω X ( t ) and δ ω Y ( t ) are the beam FWHM at time t, respectively, for the X and Y arm cavities and a 1 is a beam proportionality constant to be determined expermentally. Assuming a 1 ≈ 1 , then for cavity beams FWHM of δ ω ( t ) ≈ ( 523 . 2 ± 31 ) rad . s - 1 the output signal has the range ∣ h H ( t ) ∣ ≤ 1 × 10 - 21 , which is detectable by advanced LIGO.

scholarly journals A Schiff Base Fluorescence Enhancement Probe for Fe(III) and Its Sensing Applications in Cancer Cells

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2500 ◽  
Author(s):  
Na Hee Kim ◽  
Junho Lee ◽  
Sungnam Park ◽  
Junyang Jung ◽  
Dokyoung Kim
Keyword(s):  
Schiff Base ◽  
Laser Scanning ◽  
Fluorescence Enhancement ◽  
Aqueous Media ◽  
Cancer Cell Line ◽  
High Sensitivity ◽  
Fast Response ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sensing Applications

We report a new Schiff base fluorescent probe which senses ferric ion, Fe(III), with a significant fluorescence enhancement response. The probe showed high sensitivity (0.8 ppb), and fast response time (<10 s) of Fe(III) in aqueous media. In addition, the probe showed the ability to sense Fe(III) in a HeLa cancer cell line, with very low cytotoxicity. As a new bio-imaging probe for Fe(III), it gave bright fluorescent images in confocal laser scanning microscopy (CLSM).

Assessment of three-dimensional biofilm models through direct comparison with confocal microscopy imaging

2004 ◽  
Vol 49 (11-12) ◽  
pp. 177-185 ◽  
Author(s):  
J.B. Xavier ◽  
C. Picioreanu ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Structure Formation ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Experimental Conditions ◽  
Microscopy Imaging ◽  
Biofilm Growth ◽  
Biofilm Development ◽  
Biofilm Structure

The mathematical modeling of spatial biofilm formation that provides the capability to predict biofilm structure from first principles has been in development for the past six years. However, a direct and quantitative link between model predictions and the experimentally observed structure formation still remains to be established. This work assesses the capability of a state-of-the-art technique for three-dimensional (3D) modeling of biofilm structure, individual based modeling (IbM), to quantitatively describe the early development of a multispecies denitrifying biofilm. Model evaluation was carried out by comparison of predicted structure with that observed from two experimental datasets using confocal laser scanning microscopy (CLSM) monitoring of biofilm development in laboratory flowcells. Experimental conditions provided biofilm growth without substrate limitation, which was confirmed from substrate profiles computed by the model. 3D structures were compared quantitatively using a set of morphological parameters including the biovolume, filled-space profiles, substratum coverage, average thickness and normalized roughness. In spite of the different morphologies detectable in the two independent short-term experiments analyzed here, the model was capable of accurate fitting data from both experiments. Prediction of structure formation was precise, as expressed by the set of morphology parameters used.

scholarly journals Colocalization Analysis of Lipo-Deoxyribozyme Consisting of DNA and Protic Catalysts in a Vesicle-Based Protocellular Membrane Investigated by Confocal Microscopy

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1364
Author(s):  
Yuiko Hirata ◽  
Muneyuki Matsuo ◽  
Kensuke Kurihara ◽  
Kentaro Suzuki ◽  
Shigenori Nonaka ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Membrane Lipids ◽  
High Sensitivity ◽  
Cationic Lipids ◽  
Confocal Laser ◽  
Mean Deviation ◽  
Acid Catalysts ◽  
Spontaneous Formation ◽  
Cellular Life ◽  
Texas Red

The linkage between the self-reproduction of compartments and the replication of DNA in a compartment is a crucial requirement for cellular life. In our giant vesicle (GV)-based model protocell, this linkage is achieved through the action of a supramolecular catalyst composed of membrane-intruded DNA and amphiphilic acid catalysts (C@DNA) in a GV membrane. In this study, we examined colocalization analysis for the formation of the supramolecular catalyst using a confocal laser scanning fluorescence microscope with high sensitivity and resolution. Red fluorescence spots emitted from DNA tagged with Texas Red (Texas Red-DNA) were observed in a GV membrane stained with phospholipid tagged with BODIPY (BODIPY-HPC). To our knowledge, this is the first direct observation of DNA embedded in a GV-based model protocellular membrane containing cationic lipids. Colocalization analysis based on a histogram of frequencies of “normalized mean deviation product” revealed that the frequencies of positively correlated [lipophilic catalyst tagged with BODIPY (BODIPY-C) and Texas Red-DNA] were significantly higher than those of [BODIPY-HPC and Texas Red-DNA]. This result demonstrates the spontaneous formation of C@DNA in the GV membrane, which serves as a lipo-deoxyribozyme for producing membrane lipids from its precursor.

scholarly journals Interactions between L. monocytogenes and P. fluorescens in Dual-Species Biofilms under Simulated Dairy Processing Conditions

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 176
Author(s):  
Francesca Maggio ◽  
Chiara Rossi ◽  
Clemencia Chaves-López ◽  
Annalisa Serio ◽  
Luca Valbonetti ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Bacterial Species ◽  
Laser Scanning Microscopy ◽  
Blue Pigment ◽  
Confocal Laser ◽  
Processing Conditions ◽  
Experimental Conditions ◽  
Dairy Processing ◽  
Microscopy Analysis ◽  
Sessile Cells

In dairy processing environments, many bacterial species adhere and form biofilms on surfaces and equipment, leading to foodborne illness and food spoilage. Among them, Listeria monocytogenes and Pseudomonas spp. could be present in mixed-species biofilms. This study aimed to evaluate the interactions between L. monocytogenes and P. fluorescens in biofilms simulating dairy processing conditions, as well as the capability of P. fluorescens in co-culture to produce the blue pigment in a Ricotta-based model system. The biofilm-forming capability of single- and mixed-cultures was evaluated on polystyrene (PS) and stainless steel (SS) surfaces at 12 °C for 168 h. The biofilm biomass was measured, the planktonic and sessile cells and the carbohydrates in biofilms were quantified. The biofilms were also observed through Confocal Laser Scanning Microscopy analysis. Results showed that only P. fluorescens was able to form biofilms on PS. Moreover, in dual-species biofilms at the end of the incubation time (168 h at 12 °C), a lower biomass compared to P. fluorescens mono-species was observed on PS. On SS, the biofilm cell population of L. monocytogenes was higher in the dual-species than in mono-species, particularly after 48 h. Carbohydrates quantity in the dual-species system was higher than in mono-species and was revealed also at 168 h. The production of blue pigment by P. fluorescens was revealed both in single- and co-culture after 72 h of incubation (12 °C). This work highlights the interactions between the two species, under the experimental conditions studied in the present research, which can influence biofilm formation (biomass and sessile cells) but not the capability of P. fluorescens to produce blue pigment.

scholarly journals Biomechanical conditioning of the motor unit transitory force decrease following a reduction in stimulation rate

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Joanna Rakoczy ◽  
Katarzyna Kryściak ◽  
Hanna Drzymała-Celichowska ◽  
Rositsa Raikova ◽  
Jan Celichowski
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
High Sensitivity ◽  
Stimulation Frequency ◽  
Medial Gastrocnemius ◽  
High Frequency Stimulation ◽  
Muscle Fibres ◽  
Force Transmission ◽  
Experimental Conditions ◽  
Frequency Pattern

Abstract Background The biomechanical background of the transitory force decrease following a sudden reduction in the stimulation frequency under selected experimental conditions was studied on fast resistant motor units (MUs) of rat medial gastrocnemius in order to better understand the mechanisms of changes in force transmission. Methods Firstly, MUs were stimulated with three-phase trains of stimuli (low–high–low frequency pattern) to identify patterns when the strongest force decrease (3–36.5%) following the middle high frequency stimulation was observed. Then, in the second part of experiments, the MUs which presented the largest force decrease in the last low-frequency phase were alternatively tested under one of five conditions to analyse the influence of biomechanical factors of the force decrease: (1) determine the influence of muscle stretch on amplitude of the force decrease, (2) determine the numbers of interpulse intervals necessary to evoke the studied phenomenon, (3) study the influence of coactivation of other MUs on the studied force decrease, (4) test the presence of the transitory force decrease at progressive changes in stimulation frequency, (5) and perform mathematical analysis of changes in twitch-shape responses to individual stimuli within a tetanus phase with the studied force decrease. Results Results indicated that (1) the force decrease was highest when the muscle passive stretch was optimal for the MU twitch (100 mN); (2) the middle high-frequency burst of stimuli composed of at least several pulses was able to evoke the force decrease; (3) the force decrease was eliminated by a coactivation of 10% or more MUs in the examined muscle; (4) the transitory force decrease occured also at the progressive decrease in stimulation frequency; and (5) a mathematical decomposition of contractions with the transitory force decrease into twitch-shape responses to individual stimuli revealed that the force decrease in question results from the decrease of twitch forces and a shortening in contraction time whereas further force restitution is related to the prolongation of relaxation. Conclusions High sensitivity to biomechanical conditioning indicates that the transitory force decrease is dependent on disturbances in the force transmission predominantly by collagen surrounding active muscle fibres.

scholarly journals Functional Imaging of Mitochondria in Saponin-permeabilized Mice Muscle Fibers

1998 ◽  
Vol 140 (5) ◽  
pp. 1091-1099 ◽  
Author(s):  
Andrey V. Kuznetsov ◽  
Oleg Mayboroda ◽  
Dagmar Kunz ◽  
Kirstin Winkler ◽  
Walter Schubert ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Flow Cytometric Analysis ◽  
Redox System ◽  
Quadriceps Muscle ◽  
Confocal Laser ◽  
Functional Responses ◽  
Experimental Conditions ◽  
Fluorescent Marker ◽  
Ratio Imaging ◽  
Fluorescence Imaging Microscopy

Confocal laser-scanning and digital fluorescence imaging microscopy were used to quantify the mitochondrial autofluorescence changes of NAD(P)H and flavoproteins in unfixed saponin-permeabilized myofibers from mice quadriceps muscle tissue. Addition of mitochondrial substrates, ADP, or cyanide led to redox state changes of the mitochondrial NAD system. These changes were detected by ratio imaging of the autofluorescence intensities of fluorescent flavoproteins and NAD(P)H, showing inverse fluorescence behavior. The flavoprotein signal was colocalized with the potentiometric mitochondria-specific dye dimethylaminostyryl pyridyl methyl iodide (DASPMI), or with MitoTracker™ Green FM, a constitutive marker for mitochondria. Within individual myofibers we detected topological mitochondrial subsets with distinct flavoprotein autofluorescence levels, equally responding to induced rate changes of the oxidative phosphorylation. The flavoprotein autofluorescence levels of these subsets differed by a factor of four. This heterogeneity was substantiated by flow-cytometric analysis of flavoprotein and DASPMI fluorescence changes of individual mitochondria isolated from mice skeletal muscle. Our data provide direct evidence that mitochondria in single myofibers are distinct subsets at the level of an intrinsic fluorescent marker of the mitochondrial NAD–redox system. Under the present experimental conditions these subsets show similar functional responses.

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