2,334 research outputs found
Synthesis and Biological Characterization of a New Norbormide Derived Bodipy FL-Conjugated Fluorescent Probe for Cell Imaging
Background: Norbormide (NRB) is a selective rat toxicant endowed with vasoconstrictor activity confined to the rat peripheral arteries. In a recent work we used a fluorescent derivative of NRB (NRB-AF12), obtained by coupling the NBD fluorophore to the parent molecule via a linker, in order to gain information about the possible site of action of the unlabeled compound. We found that NRB-AF12 labeled intracellular organelles in both NRB-sensitive and -insensitive cells and we accordingly proposed its use as a scaffold for the development of a new class of fluorescent probes. In this study, we examined the fluorescent properties of a BODIPY FL-conjugated NRB probe (MC009) developed: (A) to verify if NRB distribution could be influenced by the attached fluorophore; (B) to improve the fluorescent performance of NRB-AF12. Methods: MC009 characteristics were investigated by confocal fluorescence microscopy, in freshly isolated rat caudal artery myocytes (FIRCAM) and in LX2 cells, representative of NRB-sensitive and insensitive cells, respectively. Main results: In both FIRCAM and LX2 cells MC009 stained endoplasmic reticulum, mitochondria, Golgi apparatus and lipid droplets, revealing the same intracellular distribution as NRB-AF12, and, at the same time, had both improved photostability and gave a more intense fluorescent signal at lower concentrations than was possible with NRB-AF12, which resulted in a better and finer visualization of intracellular structures. Furthermore, MC009 was effective in cellular labeling in both living and fixed cells. At the concentration used to stain the cells, MC009 did not show any cytotoxic effect and did not affect the regular progression of cell cycle and division. Conclusions: This study demonstrates that the distribution of fluorescently labeled NRB is not affected by the type of fluorophore attached to the parent compound, supporting the idea that the localization of the fluorescent derivatives may reasonably reflect that of the parent compound. In addition, we observed a marked improvement in the fluorescent properties of BODIPY FL-conjugated NRB (MC009) over its NBD-derived counterpart (NRB-AF12), confirming NRB as a scaffold for the development of new, high performance, non-toxic fluorescent probes for the labeling of intracellular structures in both living and fixed cells
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Video games as a recovery intervention for ostracism
Research has begun to explore the potential benefits of video games as intervention methods for a variety of issues. This study explores the role of video games in assisting the recovery from ostracism. Undergraduate volunteers (nâŻ=âŻ117) were either included or excluded during a game of cyberball, after which their relational needs (self-esteem and belonging), as well as positive and negative affect were assessed. They were then randomly allocated to a video game condition (self-esteem enhancing, pro-social, or control) and following 5âŻmin of play, needs and affect were reassessed. Participantsâ anti/pro â social responses were also recorded after administering the video game intervention. Results showed that all game conditions were successful in restoring psychological needs and affect scores following ostracism. Additionally, the pro-social game was the most successful in increasing positive affect following ostracism. There were no differences in pro-social behaviour scores between groups, with participants demonstrating neutral to social behaviour scores. This study is the first of its kind to demonstrate that games have the potential to restore needs and affect following ostracism. Exploring such low-cost and easily accessible intervention methods is crucial, given that ostracism is a prevalent issue with serious negative effects on wellbeing. This study adds to the growing research demonstrating the therapeutic benefits of video games, suggesting it is a valuable method of intervention for ostracism that needs to be further explored
âOff With Their Headsâ: British Prime Ministers and the Power to Dismiss
The British prime ministerâs power to appoint and dismiss ministers is probably his most important single power. This article explores how prime ministers from Macmillan to Blair have used that power. The article considers the criteria that prime ministers use when choosing to appoint or dismiss individuals from office before examining the calculations and miscalculations that prime ministers have made in practice. Finally, the article analyses the way that prime ministers have exercised, in particular, their power to dismiss and finds that Thatcher was far more likely than others to sack cabinet colleagues on ideological or policy grounds. The article emphasizes that prime ministersâ relationships with especially powerful ministers â âbig beasts of the jungleâ â are crucial to an understanding of British government at the top.</jats:p
Live applications of norbormide-based fluorescent probes in Drosophila melanogaster
In this study we investigated the performance of two norbormide (NRB)-derived fluorescent probes, NRBMC009 (green) and NRBZLW0047 (red), on dissected, living larvae of Drosophila, to verify their potential application in confocal microscopy imaging in vivo. To this end, larval tissues were exposed to NRB probes alone or in combination with other commercial dyes or GFP-tagged protein markers. Both probes were rapidly internalized by most tissues (except the central nervous system) allowing each organ in the microscope field to be readily distinguished at low magnification. At the cellular level, the probes showed a very similar distribution (except for fat bodies), defined by loss of signal in the nucleus and plasma membrane, and a preferential localization to endoplasmic reticulum (ER) and mitochondria. They also recognized ER and mitochondrial phenotypes in the skeletal muscles of fruit fly models that had loss of function mutations in the atlastin and mitofusin genes, suggesting NRBMC009 and NRBZLW0047 as potentially useful in vivo screening tools for characterizing ER and mitochondria morphological alterations. Feeding of larvae and adult Drosophilae with the NRB-derived dyes led to staining of the gut and its epithelial cells, revealing a potential role in food intake assays. In addition, when flies were exposed to either dye over their entire life cycle no apparent functional or morphological abnormalities were detected. Rapid internalization, a bright signal, a compatibility with other available fluorescent probes and GFP-tagged protein markers, and a lack of toxicity make NRBZLW0047 and, particularly, NRBMC009 one of the most highly performing fluorescent probes available for in vivo microscopy studies and food intake assay in Drosophila
Reemerging Leptospirosis, California
Leptospirosis is a reemerging infectious disease in California. Leptospirosis is the most widespread zoonosis throughout the world, though it is infrequently diagnosed in the continental United States. From 1982 to 2001, most reported California cases occurred in previously healthy young adult white men after recreational exposures to contaminated freshwater. We report five recent cases of human leptospirosis acquired in California, including the first documented common-source outbreak of human leptospirosis acquired in this state, and describe the subsequent environmental investigation. Salient features in the California cases include high fever with uniform renal impairment and mild hepatitis. Because leptospirosis can progress rapidly if untreated, this reemerging infection deserves consideration in febrile patients with a history of recreational freshwater exposure, even in states with a low reported incidence of infection
Phenotypic screening identifies a trisubstituted imidazo[1,2-a]pyridine series that induces differentiation in multiple AML cell lines
Acute myeloid leukaemia (AML) is an aggressive type of leukaemia with low rates of long-term survival. While the current standard of care is based on cytotoxic chemotherapy, a promising emerging approach is differentiation therapy. However, most current differentiating agents target specific mutations and are effective only in certain patient subtypes. To identify agents which may be effective in wider population cohorts, we performed a phenotypic screen with the myeloid marker CD11b and identified a compound series that was able to differentiate AML cell lines in vitro regardless of their mutation status. Structure-activity relationship studies revealed that replacing the formamide and catechol methyl ether groups with sulfonamide and indazole respectively improved the in vitro metabolic profile of the series while maintaining the differentiation profile in multiple cell lines. This optimisation exercise enabled progression of a lead compound to in vivo efficacy testing. Our work supports the promise of phenotypic screening to identify novel small molecules that induce differentiation in a wide range of AML subtypes
Structure and rational engineering of the PglX methyltransferase and specificity factor for BREX phage defence.
Bacteria have evolved a broad range of systems that provide defence against their viral predators, bacteriophages. Bacteriophage Exclusion (BREX) systems recognise and methylate 6âbp non-palindromic motifs within the host genome, and prevent replication of non-methylated phage DNA that encodes these same motifs. How BREX recognises cognate motifs has not been fully understood. In this study we characterise BREX from pathogenic Salmonella and present X-ray crystallographic structures of the conserved BREX protein, PglX. The PglX N-terminal domain encodes the methyltransferase, whereas the C-terminal domain is for motif recognition. We also present the structure of PglX bound to the phage-derived DNA mimic, Ocr, an inhibitor of BREX activity. Our analyses propose modes for DNA-binding by PglX and indicate that both methyltransferase activity and defence require larger BREX complexes. Through rational engineering of PglX we broaden both the range of phages targeted, and the host motif sequences that are methylated by BREX. Our data demonstrate that PglX is used to recognise specific DNA sequences for BREX activity, contributing to motif recognition for both phage defence and host methylation
Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-Degenerate Double-Detonation Type Ia Supernovae
Double detonations in double white dwarf (WD) binaries undergoing unstable
mass transfer have emerged in recent years as one of the most promising Type Ia
supernova (SN Ia) progenitor scenarios. One potential outcome of this
"dynamically driven double-degenerate double-detonation" (D^6) scenario is that
the companion WD survives the explosion and is flung away with a velocity equal
to its > 1000 km/s pre-SN orbital velocity. We perform a search for these
hypervelocity runaway WDs using Gaia's second data release. In this paper, we
discuss seven candidates followed up with ground-based instruments. Three
sources are likely to be some of the fastest known stars in the Milky Way, with
total Galactocentric velocities between 1000 and 3000 km/s, and are consistent
with having previously been companion WDs in pre-SN Ia systems. However,
although the radial velocity of one of the stars is > 1000 km/s, the radial
velocities of the other two stars are puzzlingly consistent with 0. The
combined five-parameter astrometric solutions from Gaia and radial velocities
from follow-up spectra yield tentative 6D confirmation of the D^6 scenario. The
past position of one of these stars places it within a faint, old SN remnant,
further strengthening the interpretation of these candidates as hypervelocity
runaways from binary systems that underwent SNe Ia.Comment: Accepted for publication in ApJ. Minor corrections for clarity. D6
spectra are available as ancillary data file
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
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