3,919 research outputs found
Eye Suppression, A Novel Function of Teashirt, Requires Wingless Signaling
Teashirt (tsh) encodes a Drosophila zinc-finger protein. Misexpression of tsh has been shown to induce ectopic eye formation in the antenna. We report that tsh can suppress eye development. This novel function of tsh is due to the induction of homothorax (hth), a known repressor of eye development, and requires Wingless (WG) signaling. Interestingly, tsh has different functions in the dorsal and ventral eye, suppressing eye development close to the ventral margin, while promoting eye development near the dorsal margin. It affects both growth of eye disc and retinal cell differentiation
Comparison of exon 5 sequences from 35 class I genes of the BALB/c mouse
DNA sequences of the fifth exon, which encodes the transmembrane domain, were determined for the BALB/c mouse class I MHC genes and used to study the relationships between them. Based on nucleotide sequence similarity, the exon 5 sequences can be divided into seven groups. Although most members within each group are at least 80% similar to each other, comparison between groups reveals that the groups share little similarity. However, in spite of the extensive variation of the fifth exon sequences, analysis of their predicted amino acid translations reveals that only four class I gene fifth exons have frameshifts or stop codons that terminate their translation and prevent them from encoding a domain that is both hydrophobic and long enough to span a lipid bilayer. Exactly 27 of the remaining fifth exons could encode a domain that is similar to those of the transplantation antigens in that it consists of a proline-rich connecting peptide, a transmembrane segment, and a cytoplasmic portion with membrane-anchoring basic residues. The conservation of this motif in the majority of the fifth exon translations in spite of extensive variation suggests that selective pressure exists for these exons to maintain their ability to encode a functional transmembrane domain, raising the possibility that many of the nonclassical class I genes encode functionally important products
HIFLUGCS: Galaxy cluster scaling relations between X-ray luminosity, gas mass, cluster radius, and velocity dispersion
We present relations between X-ray luminosity and velocity dispersion
(L-sigma), X-ray luminosity and gas mass (L-Mgas), and cluster radius and
velocity dispersion (r500-sigma) for 62 galaxy clusters in the HIFLUGCS, an
X-ray flux-limited sample minimizing bias toward any cluster morphology. Our
analysis in total is based on ~1.3Ms of clean X-ray XMM-Newton data and 13439
cluster member galaxies with redshifts. Cool cores are among the major
contributors to the scatter in the L-sigma relation. When the
cool-core-corrected X-ray luminosity is used the intrinsic scatter decreases to
0.27 dex. Even after the X-ray luminosity is corrected for the cool core, the
scatter caused by the presence of cool cores dominates for the low-mass
systems. The scatter caused by the non-cool-core clusters does not strongly
depend on the mass range, and becomes dominant in the high-mass regime. The
observed L-sigma relation agrees with the self-similar prediction, matches that
of a simulated sample with AGN feedback disregarding six clusters with <45
cluster members with spectroscopic redshifts, and shows a common trend of
increasing scatter toward the low-mass end, i.e., systems with sigma<500km/s. A
comparison of observations with simulations indicates an AGN-feedback-driven
impact in the low-mass regime. The best fits to the relations
for the disturbed clusters and undisturbed clusters in the observational sample
closely match those of the simulated samples with and without AGN feedback,
respectively. This suggests that one main cause of the scatter is AGN activity
providing feedback in different phases, e.g., during a feedback cycle. The
slope and scatter in the observed r500-sigma relation is similar to that of the
simulated sample with AGN feedback except for a small offset but still within
the scatter.Comment: 45 pages, 28 figures, A&A proof-version, high-resolution figures in
Appendix F can be found in the electronic version on the A&A we
Two-photon Lithography for 3D Magnetic Nanostructure Fabrication
Ferromagnetic materials have been utilised as recording media within data
storage devices for many decades. Confinement of the material to a two
dimensional plane is a significant bottleneck in achieving ultra-high recording
densities and this has led to the proposition of three dimensional (3D)
racetrack memories that utilise domain wall propagation along nanowires.
However, the fabrication of 3D magnetic nanostructures of complex geometry is
highly challenging and not easily achievable with standard lithography
techniques. Here, by using a combination of two-photon lithography and
electrochemical deposition, we show a new approach to construct 3D magnetic
nanostructures of complex geometry. The magnetic properties are found to be
intimately related to the 3D geometry of the structure and magnetic imaging
experiments provide evidence of domain wall pinning at a 3D nanostructured
junction
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Distinct genomic routes underlie transitions to specialised symbiotic lifestyles in deep-sea annelid worms.
Bacterial symbioses allow annelids to colonise extreme ecological niches, such as hydrothermal vents and whale falls. Yet, the genetic principles sustaining these symbioses remain unclear. Here, we show that different genomic adaptations underpin the symbioses of phylogenetically related annelids with distinct nutritional strategies. Genome compaction and extensive gene losses distinguish the heterotrophic symbiosis of the bone-eating worm Osedax frankpressi from the chemoautotrophic symbiosis of deep-sea Vestimentifera. Osedax's endosymbionts complement many of the host's metabolic deficiencies, including the loss of pathways to recycle nitrogen and synthesise some amino acids. Osedax's endosymbionts possess the glyoxylate cycle, which could allow more efficient catabolism of bone-derived nutrients and the production of carbohydrates from fatty acids. Unlike in most Vestimentifera, innate immunity genes are reduced in O. frankpressi, which, however, has an expansion of matrix metalloproteases to digest collagen. Our study supports that distinct nutritional interactions influence host genome evolution differently in highly specialised symbioses
Differential requirements for the Pax6(5a) genes eyegone and twin of eyegone during eye development in Drosophila
In eye development the tasks of tissue specification and cell proliferation are regulated, in part, by the Pax6 and Pax6(5a) proteins respectively. In vertebrates, Pax6(5a) is generated as an alternately spliced isoform of Pax6. This stands in contrast to the fruit fly, Drosophila melanogaster, which has two Pax6(5a) homologs that are encoded by the eyegone and twin of eyegone genes. In this report we set out to determine the respective contributions that each gene makes to the development of the fly retina. Here we demonstrate that both eyg and toe encode transcriptional repressors, are expressed in identical patterns but at significantly different levels. We further show, through a molecular dissection of both proteins, that Eyg makes differential use of several domains when compared to Toe and that the number of repressor domains also differs between the two Pax6(5a) homologs. We predict that these results will have implications for elucidating the functional differences between closely related members of other Pax subclasses
TL1A/DR3 axis involvement in the inflammatory cytokine network during pulmonary sarcoidosis
BACKGROUND:
TNF-like ligand 1A (TL1A), a recently recognized member of the TNF superfamily, and its death domain receptor 3 (DR3), firstly identified for their relevant role in T lymphocyte homeostasis, are now well-known mediators of several immune-inflammatory diseases, ranging from rheumatoid arthritis to inflammatory bowel diseases to psoriasis, whereas no data are available on their involvement in sarcoidosis, a multisystemic granulomatous disease where a deregulated T helper (Th)1/Th17 response takes place.
METHODS:
In this study, by flow cytometry, real-time PCR, confocal microscopy and immunohistochemistry analyses, TL1A and DR3 were investigated in the pulmonary cells and the peripheral blood of 43 patients affected by sarcoidosis in different phases of the disease (29 patients with active sarcoidosis, 14 with the inactive form) and in 8 control subjects.
RESULTS:
Our results demonstrated a significant higher expression, both at protein and mRNA levels, of TL1A and DR3 in pulmonary T cells and alveolar macrophages of patients with active sarcoidosis as compared to patients with the inactive form of the disease and to controls. In patients with sarcoidosis TL1A was strongly more expressed in the lung than the blood, i.e., at the site of the involved organ. Additionally, zymography assays showed that TL1A is able to increase the production of matrix metalloproteinase 9 by sarcoid alveolar macrophages characterized, in patients with the active form of the disease, by reduced mRNA levels of the tissue inhibitor of metalloproteinase (TIMP)-1.
CONCLUSIONS:
These data suggest that TL1A/DR3 interactions are part of the extended and complex immune-inflammatory network that characterizes sarcoidosis during its active phase and may contribute to the pathogenesis and to the progression of the disease
Accuracy of the diagnosis of malignant hyperthermia in hospital discharge records
Background: In 1997, the International Classification of Diseases, 9th Revision Clinical Modification (ICD-9CM) coding system introduced the code for malignant hyperthermia (MH) (995.86). The aim of the current study was to estimate the accuracy of coding for MH in hospital discharge records. Materials and methods: A panel of anesthesiologists expert in MH, reviewed medical records for patients with a discharge diagnosis of MH based on ICD-9 or ICD-10 codes from January 1, 2006 to December 31, 2008 at six tertiary care medical centers in North America. All cases were categorized as possible, probable, or fulminant MH, history of MH (family or personal) or other. Results: A total of 47 medical records were identified and reviewed by three experts. The mean age of patients was 40 years and 49% were male. A surgical procedure with general anesthesia was documented in 68% of patients. However, only 23.4% were judged to have had a possible, probable, or fulminant MH event. Dantrolene was given in 81% of MH cases. Family and personal history of MH accounted for 46.8% of cases. High fever without evidence of MH during admission accounted for 23.4%, and in 6.4% cases the reason for the code was not apparent. All patients judged to have an incident MH event survived to discharge. Conclusions: Medical record coding for MH typically includes both incident cases as well as a history of MH. The positive predictive value of about 70% for MH in this study are consistent with other studies of ICD-9 accuracy in the US. However, epidemiologic studies based on coded diagnosis of MH should carefully distinguish between incident cases related to anesthesia, cases unrelated to anesthesia and diagnosis based on history only
Sustained Release of Multiple Growth Factors from Injectable Polymeric System as a Novel Therapeutic Approach Towards Angiogenesis
The aim was to investigate that a bio-degradable alginate and poly lactide-co-glycolide (PLG) system capable of delivering growth factors sequentially would be superior to single growth factor delivery in promoting neovascularization and improving perfusion
Real-Time CARS Imaging Reveals a Calpain-Dependent Pathway for Paranodal Myelin Retraction during High-Frequency Stimulation
High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS) imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down
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