Search results for "laser"

External Influences on Invertebrate Brain Histamine and Related Compounds via an Automated Derivatization Method for Capillary Electrophoresis.

2017

8 pages; International audience; Histamine has been shown to modulate visual system and photic behavior in arthropods. However, few methods are available for the direct quantification of histamine and its precursor and metabolites in arthropod brain. In this work, a method for the separation of histamine, its precursor histidine, and its metabolite N-methyl-histamine from brain extracts of a freshwater crustacean has been developed using capillary electrophoresis with laser-induced fluorescence detection. Molecules were tagged on their primary amine function with naphthalene-2,3-dicarboxaldehyde, but derivatized histamine and N-methyl-histamine exhibited poor stability in contrast to deriva…

Direct identification of microorganisms from thioglycolate broth by MALDI-TOF MS.

2017

We developed an easy MALDI-TOF MS-based assay to identify microorganisms directly from thioglycolate broth. A total of 101 positive thioglycolate broths inoculated with 15 different kinds of samples were evaluated. In 91 samples (90.1%), direct MALDI-TOF MS identifications were the same as those obtained after conventional laboratory procedures including subcultures. In 10 samples misidentified by direct processing, yeasts or mixed cultures grew in the thioglycolate subcultures, or high cellular debris hampered a correct analysis. This rapid method can provide a fast, clinically- relevant species-level identification without disturbing the daily workflow in clinical microbiology laboratorie…

Field tests of astrometric subsystem

2016

The paper presents results of astrometric subsystem’s functionality tests for space object laser ranging and astrometric position determination device, which is under construction in the Institute of Geodesy and Geoinformatics (GGI) of the University of Latvia. Properties of hardware performance for astrometric image acquisition were evaluated and optimal parameters have been selected. Software for image processing and calculation of instrument orientation was tested and adjustments have been made for real-time operation support. Object tracking properties were evaluated, and mount error model parameters were calculated, using test measurements.

2016

AbstractGlaucoma related proteomic changes have been documented in cell and animal models. However, proteomic studies investigating on human retina samples are still rare. In the present work, retina samples of glaucoma and non-glaucoma control donors have been examined by a state-of-the-art mass spectrometry (MS) workflow to uncover glaucoma related proteomic changes. More than 600 proteins could be identified with high confidence (FDR < 1%) in human retina samples. Distinct proteomic changes have been observed in 10% of proteins encircling mitochondrial and nucleus species. Numerous proteins showed a significant glaucoma related level change (p < 0.05) or distinct tendency of altera…

The seed endosphere of Anadenanthera colubrina is inhabited by a complex microbiota, including Methylobacterium spp. and Staphylococcus spp. with pot…

2018

Background and aims: Plant seeds are emerging micro–habitats, whose importance as reservoir and vector of beneficial microbes just begins to be recognized. Here we aimed to characterize the bacterial microbiota of the Anadenanthera colubrina seed endosphere, with special focus to beneficial traits and to the colonization pattern. Methods: Cultivation–dependent (isolation from surface–sterilized seeds) and cultivation–independent (pyrosequencing of 16S rRNA gene from metagenomic seed DNA) analyses, functional tests and microscopical investigations (fluorescence in situ hybridization coupled with confocal laser scanning microscopy (FISH-CLSM) were performed. Results: We isolated several Methy…

The O-antigen of Plesiomonas shigelloides serotype O36 containing pseudaminic acid

2016

The structure of the repeating unit of O-antigen of Plesiomonas shigelloides serotype O36 has been investigated by 1H and 13C NMR spectroscopy, matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry and chemical methods. The new structure of trisaccharide has been established: →4)-β-Pse5Ac7(R3Hb)-(2 → 4)-β-D-Galp-(1 → 3)-β-D-GlcpNAc-(1→ These trisaccharide O-antigen units substitute the core undecasaccharide at C-4 of the β-D-GlcpNAc residue. The core oligosaccharide and lipid A are identical with these of the serotype O17 (PCM 2231) (Maciejewska, A., Lukasiewicz, J., Kaszowska, M., Jachymek, W., Man-Kupisinska, A.; Lugowski, C. Mar. Drugs.2013, 11 (2), 440–454; Lukasi…

Trichomonicidal and parasite membrane damaging activity of bidesmosic saponins from Manilkara rufula.

2017

The infection caused by Trichomonas vaginalis is the most common but overlooked non-viral sexually transmitted disease worldwide. Treatment relies on one class of drugs, the 5-nitroimidazoles, but resistance is widespread. New drugs are urgently needed. We reported the effect of crude and purified saponin fractions of Manilkara rufula against Trichomonas vaginalis. The compound responsible for antitrichomonal activity was isolated and identified as an uncommon bidesmosic saponin, Mi-saponin C. This saponin eliminated parasite viability without toxicity against the human vaginal epithelial line (HMVII). In addition, the isolated saponin fraction improved the metronidazole effect against a me…

Variance component analysis to assess protein quantification in biomarker discovery. Application to MALDI-TOF mass spectrometry.

2017

International audience; Controlling the technological variability on an analytical chain is critical for biomarker discovery. The sources of technological variability should be modeled, which calls for specific experimental design, signal processing, and statistical analysis. Furthermore, with unbalanced data, the various components of variability cannot be estimated with the sequential or adjusted sums of squares of usual software programs. We propose a novel approach to variance component analysis with application to the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology and use this approach for protein quantification by a classical signal processing algori…

Modulation of mitochondriotropic properties of cyanine dyes by in organello copper-free click reaction

2017

Cyanine (Cy) dyes show a general propensity to localize in polarized mitochondria. This mitochondriotropism was used to perform a copper-free click reaction in the mitochondria of living cells. The in organello reaction of dyes Cy3 and Cy5 led to a product that was easily traceable by Forster resonance energy transfer (FRET). As determined by confocal laser scanning microscopy, the Cy3-Cy5 conjugate showed enhanced retention in mitochondria, relative to that of the starting compounds. This enhancement of a favorable property can be achieved by synthesis in organello, but not outside mitochondria.

FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices.

2021

International audience; Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever- increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among d…