278 research outputs found
Transcription of the dystrophin gene in Duchenne muscular dystrophy muscle
AbstractDystrophin is the recently discovered defective gene product in Duchenne and Becker muscular dystrophy (DMD and BMD). Dystrophin transcripts have been amplified and identified in diagnostic needle muscle biopsy samples using the polymerase chain reaction (PCR) procedure. Using 5′- and 3′-primers, dystrophin transcripts can be detected in both DMD and BMD muscle biopsies, on either side of defined deletions within the dystrophin gene
Kinematics of Spiral Arm Streaming in M51
We use CO and H alpha velocity fields to study the gas kinematics in the
spiral arms and interarms of M51 (NGC 5194), and fit the 2D velocity field to
estimate the radial and tangential velocity components as a function of spiral
phase (arm distance). We find large radial and tangential streaming velocities,
which are qualitatively consistent with the predictions of density wave theory
and support the existence of shocks. The streaming motions are complex, varying
significantly across the galaxy as well as along and between arms. Aberrations
in the velocity field indicate that the disk is not coplanar, perhaps as far in
as 20\arcsec\ (800 pc) from the center. Velocity profile fits from CO and H
alpha are typically similar, suggesting that most of the H alpha emission
originates from regions of recent star formation. We also explore vortensity
and mass conservation conditions. Vortensity conservation, which does not
require a steady state, is empirically verified. The velocity and density
profiles show large and varying mass fluxes, which are inconsistent with a
steady flow for a single dominant global spiral mode. We thus conclude that the
spiral arms cannot be in a quasi-steady state in any rotating frame, and/or
that out of plane motions may be significant.Comment: 50 pages, including 20 figures; Accepted for publication in ApJ. PDF
version with high resolution figures available at
http://www.astro.umd.edu/~shetty/Research
Versatile, Cheap, Readily Modifiable Sample Delivery Method for Analysis of Air-/Moisture-Sensitive Samples Using Atmospheric Pressure Solids Analysis Probe Mass Spectrometry
A cheap, versatile, readily modified, and reusable glass probe system enabling delivery of solid air-/moisture-sensitive samples for mass spectrometric (MS) analysis using an Atmospheric pressure Solids Analysis Probe (ASAP) is described. The simplicity of the design allows quick and easy ASAP MS analyses of sensitive solid and liquid samples without the need for any modifications to commercially available vertically loaded ASAP mass spectrometers. A comparison of ASAP mass spectra obtained for metal complexes under air and an inert atmosphere is given
Scorpion Venom Antimicrobial Peptides Induce Siderophore Biosynthesis and Oxidative Stress Responses in Escherichia coli
The increasing development of microbial resistance to classical antimicrobial
agents has led to the search for novel antimicrobials. Antimicrobial peptides (AMPs) derived
from scorpion and snake venoms offer an attractive source for the development of novel
therapeutics. Smp24 (24 amino acids [aa]) and Smp43 (43 aa) are broad-spectrum AMPs
that have been identified from the venom gland of the Egyptian scorpion Scorpio maurus
palmatus and subsequently characterized. Using a DNA microarray approach, we examined
the transcriptomic responses of Escherichia coli to subinhibitory concentrations of Smp24
and Smp43 peptides following 5 h of incubation. Seventy-two genes were downregulated
by Smp24, and 79 genes were downregulated by Smp43. Of these genes, 14 genes were
downregulated in common and were associated with bacterial respiration. Fifty-two
genes were specifically upregulated by Smp24. These genes were predominantly
related to cation transport, particularly iron transport. Three diverse genes were independently upregulated by Smp43. Strains with knockouts of differentially regulated
genes were screened to assess the effect on susceptibility to Smp peptides. Ten mutants
in the knockout library had increased levels of resistance to Smp24. These genes were
predominantly associated with cation transport and binding. Two mutants increased resistance to Smp43. There was no cross-resistance in mutants resistant to Smp24 or
Smp43. Five mutants showed increased susceptibility to Smp24, and seven mutants
showed increased susceptibility to Smp43. Of these mutants, formate dehydrogenase
knockout (fdnG) resulted in increased susceptibility to both peptides. While the electrostatic association between pore-forming AMPs and bacterial membranes followed by
integration of the peptide into the membrane is the initial starting point, it is clear that
there are numerous subsequent additional intracellular mechanisms that contribute to
their overall antimicrobial effect.
IMPORTANCE The development of life-threatening resistance of pathogenic bacteria to the
antibiotics typically in use in hospitals and the community today has led to an urgent need
to discover novel antimicrobial agents with different mechanisms of action. As an ancient
host defense mechanism of the innate immune system, antimicrobial peptides (AMPs) are
attractive candidates to fill that role. Scorpion venoms have proven to be a rich source of
AMPs. Smp24 and Smp43 are new AMPs that have been identified from the venom gland
of the Egyptian scorpion Scorpio maurus palmatus, and these peptides can kill a wide range
of bacterial pathogens. By better understanding how these AMPs affect bacterial cells, we
can modify their structure to make better drugs in the future
Studies on a Ca2+- and Cyclic Nucleotide-Independent H1 Histone Kinase Purified from Rabbit Skeletal Muscle
In an attempt to elucidate the regulatory mechanism of microsomal function by protein phosphorylation, one of the major protein kinases obtained during the preparation of the microsomal fraction of rabbit skeletal muscle was partially purified and characterized. This enzyme was a protein serine/threonine kinase and showed similar, but not completely same properties as those of Ca 2+-phospholipid-dependent protein kinase (protein kinase C), judging from its elution profile from an anion-exchange column, molecular mass, responses to protein kinase activators or inhibitors and the substrate specificity. These results suggest a possible implication of this Ca 2+- and cyclic nucleotide-independent H1 histone kinase in protein phosphorylation of microsomal protein(s), although the exact role and the mechanism of regulation of this enzyme are not clear at this time
High-Mass Cloud Cores in the eta Carinae Giant Molecular Cloud
We carried out an unbiased survey for massive dense cores in the giant
molecular cloud associated with eta Carinae with the NANTEN telescope in 12CO,
13CO, and C18O 1-0 emission lines. We identified 15 C18O cores. Two of the 15
cores are associated with IRAS point sources whose luminosities are larger than
10^4 Lo, which indicates that massive star formation is occuring within these
cores. Five cores including the two with IRAS sources are associated with MSX
point sources. We detected H13CO+ (1-0) emission toward 4 C18O cores, one of
which is associated with neither IRAS nor MSX point sources. This core shows
the presence of a bipolar molecular outflow in 12CO (2-1), which indicates that
star formation is also occuring in the core. In total, six C18O cores out of 15
are experienced star formation, and at least 2 of 15 are massive-star forming
cores in the eta Car GMC. We found that massive star formation occurs
preferentially in cores with larger column density, mass, number density, and
smaller ratio of virial mass to LTE mass Mvir/M. We also found that the cores
in the eta Car GMC are characterized by large line width and Mvir/M on average
compared to the cores in other GMCs. We investigated the origin of a large
amount of turbulence in the eta Car GMC. We propose the possibility that the
large turbulence was pre-existing when the GMC was formed, and is now
dissipating. Mechanisms such as multiple supernova explosions in the Carina
flare supershell may have contributed to form a GMC with a large amount of
turbulence.Comment: 41 pages, including 11 fugures and 9 tables. Accepted by ApJ. Author
changed. Paper with high resolution figures is available at
http://astrol.cias.osakafu-u.ac.jp/~yonekura/work/paper/etaCar
Quality of private and public ambulatory health care in low and middle income countries: systematic review of comparative studies
Paul Garner and colleagues conducted a systematic review of 80 studies to compare
the quality of private versus public ambulatory health care in low- and
middle-income countries
Characterisation of three alpha-helical antimicrobial peptides from the venom of Scorpio maurus palmatus.
Scorpion venoms provide a rich source of anti-microbial peptides. Here we characterise three from the venom of Scorpion maurus palmatus. Smp13 is biologically inactive, despite sharing homology with other antimicrobial peptides, probably because it lacks a typically charged structure. Both Smp-24 and Smp-43 have broad spectrum antimicrobial activity, disrupting bacterial membranes. In addition, there is evidence that Smp24 may inhibit DNA synthesis in Bacillus subtilis. Smp24 haemolysed red blood cells but in contrast, Smp43 was non-haemolytic. The introduction of a flexible Gly-Val-Gly hinge into the middle of Smp24 did not alter the haemolytic activity of Smp24 (as might have been predicted from earlier studies with Pandinin2 (Pin2), although C-terminal truncation of Smp-24 reduced its haemolytic activity, in agreement with earlier Pin 2 studies. Smp24 and its derivatives, as well as Smp-43, were all cytotoxic (ATP release assay) toward mammalian HepG2 liver cells. Our results highlight the beneficial effect of helical-hinge-helical conformation on promoting prokaryotic selectivity of long chain scorpion AMPs, as well as the importance of examining a wide range of mammalian cell types in cytotoxicity testing
Phospholipid dependent mechanism of smp24, an α-helical antimicrobial peptide from scorpion venom
Determining the mechanism of action of antimicrobial peptides (AMPs) is critical if they are to be developed into the clinical setting. In recent years high resolution techniques such as atomic force microscopy (AFM) have increasingly been utilised to determine AMP mechanism of action on planar lipid bilayers and live bacteria. Here we present the biophysical characterisation of a prototypical AMP from the venom of the North African scorpion Scorpio maurus palmatus termed Smp24. Smp24 is an amphipathic helical peptide containing 24 residues with a charge of + 3 and exhibits both antimicrobial and cytotoxic activity and we aim to elucidate the mechanism of action of this peptide on both membrane systems.
Using AFM, quartz crystal microbalance-dissipation (QCM-D) and liposomal leakage assays the effect of Smp24 on prototypical synthetic prokaryotic (DOPG:DOPC) and eukaryotic (DOPE:DOPC) membranes has been determined. Our data points to a toroidal pore mechanism against the prokaryotic like membrane whilst the formation of hexagonal phase non-lamellar phase structures is seen in eukaryotic like membrane. Also, phase segregation is observed against the eukaryotic membrane and this study provides direct evidence of the same peptide having multiple mechanisms of action depending on the membrane lipid composition
Evaluating psychometric properties of the Emotional Eating Scale Adapted for Children and Adolescents (EES-C) in a clinical sample of children seeking treatment for obesity: a case for the unidimensional model.
BackgroundThe Emotional Eating Scale - Adapted for Children and Adolescents (EES-C) assesses children's urge to eat in response to experiences of negative affect. Prior psychometric studies have demonstrated the high reliability, concurrent validity, and test-retest reliability of theoretically defined subconstructs among non-clinical samples of children and adolescents who were primarily healthy weight; however, no psychometric studies exist investigating the EES-C among clinical samples of children with overweight/obesity (OW/OB). Furthermore, studies conducted in different contexts have suggested a discordant number of subconstructs of emotions related to eating. The purpose of this study was to evaluate the validity of the EES-C in a clinical sample of children seeking weight-loss treatment.MethodUsing a hierarchical bi-factor approach, we evaluated the validity of the EES-C to measure a single general construct, a set of two separate correlated subconstructs, or a hierarchical arrangement of two constructs, and determined reliability in a clinical sample of treatment-seeking children with OW/OB aged 8-12 years (N = 147, mean age = 10.4 years.; mean BMI z = 2.0; female = 66%; Hispanic = 32%, White and other = 68%).ResultsComparison of factor-extraction methods suggested a single primary construct underlying EES-C in this clinical sample. The bi-factor indices provided clear evidence that most of the reliable variance in the total score (90.8 for bi-factor model with three grouping factors and 95.2 for bi-factor model with five grouping factors) was attributed to the general construct. After adjusting for relationships with the primary construct, remaining correlations among sets of items did not suggest additional reliable constructs.ConclusionResults suggest that the primary interpretive emphasis of the EES-C among treatment-seeking children with overweight or obesity should be placed on a single general construct, not on the 3- or 5- subconstructs as was previously suggested
- …