2,649 research outputs found
Antimicrobial Susceptibility Trends Observed in Urinary Pathogens Obtained From New York State
International guidelines recommend using local susceptibility data to direct empiric therapy for acute uncomplicated cystitis. We evaluated outpatient urinary isolate susceptibility trends in New York State. Nitrofurantoin had the lowest resistance prevalence whereas trimethoprim-sulfamethoxazole and fluoroquinolones had higher prevalences. This study highlights the need for local outpatient antimicrobial stewardship programs
The Rotavirus Enterotoxin NSP4 Directly Interacts with the Caveolar Structural Protein Caveolin-1
Rotavirus nonstructural protein 4 (NSP4) is known to function as an intracellular receptor at the endoplasmic reticulum (ER) critical to viral morphogenesis and is the first characterized viral enterotoxin. Exogenously added NSP4 induces diarrhea in rodent pups and stimulates secretory chloride currents across intestinal segments as measured in Ussing chambers. Circular dichroism studies further reveal that intact NSP4 and the enterotoxic peptide (NSP4114-135) that is located within the extended, C-terminal amphipathic helix preferentially interact with caveola-like model membranes. We now show colocalization of NSP4 and caveolin-1 in NSP4-transfected and rotavirus-infected mammalian cells in reticular structures surrounding the nucleus (likely ER), in the cytosol, and at the cell periphery by laser scanning confocal microscopy. A direct interaction between NSP4 residues 112 to 140 and caveolin-1 was determined by the Pro-Quest yeast two-hybrid system with full-length NSP4 and seven overlapping deletion mutants as bait, caveolin-1 as prey, and vice versa. Coimmunoprecipitation of NSP4-caveolin-1 complexes from rotavirus-infected mammalian cells demonstrated that the interaction occurs during viral infection. Finally, binding of caveolin-1 from mammalian cell lysates to Sepharose-bound, NSP4-specific synthetic peptides confirmed the yeast two-hybrid data and further delineated the binding domain to amino acids 114 to 135. We propose that the association of NSP4 and caveolin-1 contributes to NSP4 intracellular trafficking from the ER to the cell surface and speculate that exogenously added NSP4 stimulates signaling molecules located in caveola microdomains
Rotavirus NSP4: Cell Type-dependent Transport Kinetics to the Exofacial Plasma Membrane and Release from Intact Infected Cells
Background
Rotavirus NSP4 localizes to multiple intracellular sites and is multifunctional, contributing to RV morphogenesis, replication and pathogenesis. One function of NSP4 is the induction of early secretory diarrhea by binding surface receptors to initiate signaling events. The aims of this study were to determine the transport kinetics of NSP4 to the exofacial plasma membrane (PM), the subsequent release from intact infected cells, and rebinding to naïve and/or neighboring cells in two cell types.
Methods
Transport kinetics was evaluated using surface-specific biotinylation/streptavidin pull-downs and exofacial exposure of NSP4 was confirmed by antibody binding to intact cells, and fluorescent resonant energy transfer. Transfected cells similarly were monitored to discern NSP4 movement in the absence of infection or other viral proteins. Endoglycosidase H digestions, preparation of CY3- or CY5- labeled F(ab)2 fragments, confocal imaging, and determination of preferential polarized transport employed standard laboratory techniques. Mock-infected, mock-biotinylated and non-specific antibodies served as controls.
Results
Only full-length (FL), endoglycosidase-sensitive NSP4 was detected on the exofacial surface of two cell types, whereas the corresponding cell lysates showed multiple glycosylated forms. The C-terminus of FL NSP4 was detected on exofacial-membrane surfaces at different times in different cell types prior to its release into culture media. Transport to the PM was rapid and distinct yet FL NSP4 was secreted from both cell types at a time similar to the release of virus. NSP4-containing, clarified media from both cells bound surface molecules of naïve cells, and imaging showed secreted NSP4 from one or more infected cells bound neighboring cell membranes in culture. Preferential sorting to apical or basolateral membranes also was distinct in different polarized cells.
Conclusions
The intracellular transport of NSP4 to the PM, translocation across the PM, exposure of the C-terminus on the cell surface and subsequent secretion occurs via an unusual, complex and likely cell-dependent process. The exofacial exposure of the C-terminus poses several questions and suggests an atypical mechanism by which NSP4 traverses the PM and interacts with membrane lipids. Mechanistic details of the unconventional trafficking of NSP4, interactions with host-cell specific molecules and subsequent release require additional study
Rotavirus NSP4: Cell type-dependent transport kinetics to the exofacial plasma membrane and release from intact infected cells
<p>Abstract</p> <p>Background</p> <p>Rotavirus NSP4 localizes to multiple intracellular sites and is multifunctional, contributing to RV morphogenesis, replication and pathogenesis. One function of NSP4 is the induction of early secretory diarrhea by binding surface receptors to initiate signaling events. The aims of this study were to determine the transport kinetics of NSP4 to the exofacial plasma membrane (PM), the subsequent release from intact infected cells, and rebinding to naïve and/or neighboring cells in two cell types.</p> <p>Methods</p> <p>Transport kinetics was evaluated using surface-specific biotinylation/streptavidin pull-downs and exofacial exposure of NSP4 was confirmed by antibody binding to intact cells, and fluorescent resonant energy transfer. Transfected cells similarly were monitored to discern NSP4 movement in the absence of infection or other viral proteins. Endoglycosidase H digestions, preparation of CY3- or CY5- labeled F(ab)<sub>2 </sub>fragments, confocal imaging, and determination of preferential polarized transport employed standard laboratory techniques. Mock-infected, mock-biotinylated and non-specific antibodies served as controls.</p> <p>Results</p> <p>Only full-length (FL), endoglycosidase-sensitive NSP4 was detected on the exofacial surface of two cell types, whereas the corresponding cell lysates showed multiple glycosylated forms. The C-terminus of FL NSP4 was detected on exofacial-membrane surfaces at different times in different cell types prior to its release into culture media. Transport to the PM was rapid and distinct yet FL NSP4 was secreted from both cell types at a time similar to the release of virus. NSP4-containing, clarified media from both cells bound surface molecules of naïve cells, and imaging showed secreted NSP4 from one or more infected cells bound neighboring cell membranes in culture. Preferential sorting to apical or basolateral membranes also was distinct in different polarized cells.</p> <p>Conclusions</p> <p>The intracellular transport of NSP4 to the PM, translocation across the PM, exposure of the C-terminus on the cell surface and subsequent secretion occurs via an unusual, complex and likely cell-dependent process. The exofacial exposure of the C-terminus poses several questions and suggests an atypical mechanism by which NSP4 traverses the PM and interacts with membrane lipids. Mechanistic details of the unconventional trafficking of NSP4, interactions with host-cell specific molecules and subsequent release require additional study.</p
Photoacoustic dose monitoring in clinical high-energy photon beams
This work describes all stages of development (setup, optimization, performance, and first experimental measurements) of an acoustic sensor that can be used for range monitoring and dosimetry of clinical radiotherapy beams. The detection device consists of an ultrasonic transducer, a combination of preamplifiers and differential amplifiers with filtered outputs and a digital oscilloscope. Simulations of the experimental setup were carried out to study the optimal measurement geometry and choice of transducer. The dose distributions were calculated with the Monte Carlo code FLUKA, while the acoustic simulations were performed with the analytical wave transport code k-Wave. The temporal profiles of the dose pulses, in the order of mu s, were measured with a scintillating crystal coupled to a photomultiplier and used as input for the acoustic simulation. Measurements were performed in a Cyberknife (TM) radiosurgery beam and a TrueBeam unit. A lead block was submerged in water and placed partially or totally in the irradiation field in order to increase the acoustic signal. Photoacoustic signals were detected with both beams with the expected shape and time-delay, after the frequency response of the detection system was taken into account. The proposed setup can detect photoacoustic signals originating from the penumbra of the treatment fields after being processed with the appropriate image analysis tools
Incidence, scaling relations and physical conditions of ionized gas outflows in MaNGA
In this work, we investigate the strength and impact of ionised gas outflows
within MaNGA galaxies. We find evidence for outflows in 322
galaxies ( of the analysed line-emitting sample), 185 of which show
evidence for AGN activity. Most outflows are centrally concentrated with a
spatial extent that scales sublinearly with . The incidence of
outflows is enhanced at higher masses, central surface densities and deeper
gravitational potentials, as well as at higher SFR and AGN luminosity. We
quantify strong correlations between mass outflow rates and the mechanical
drivers of the outflow of the form
and . We derive a master scaling
relation describing the mass outflow rate of ionised gas as a function of
, SFR, and . Most of the observed winds are
anticipated to act as galactic fountains, with the fraction of galaxies with
escaping winds increasing with decreasing potential well depth. We further
investigate the physical properties of the outflowing gas finding evidence for
enhanced attenuation in the outflow, possibly due to metal-enriched winds, and
higher excitation compared to the gas in the galactic disk. Given that the
majority of previous studies have focused on more extreme systems with higher
SFRs and/or more luminous AGN, our study provides a unique view of the
non-gravitational gaseous motions within `typical' galaxies in the low-redshift
Universe, where low-luminosity AGN and star formation contribute jointly to the
observed outflow phenomenology.Comment: Accepted for publication in MNRAS, 27 pages, Fig 7 & 8 for scaling
wind strength with drivers, Fig 10 for master scalin
Cool outflows in MaNGA:a systematic study and comparison to the warm phase
This paper investigates the neutral gas phase of galactic winds via the Na I
D{\AA} feature within MaNGA galaxies,
and directly compares their incidence and strength to the ionized winds
detected within the same parent sample. We find evidence for neutral outflows
in 127 galaxies ( per cent of the analysed line-emitting sample). Na I
D winds are preferentially seen in galaxies with dustier central regions and
both wind phases are more often found in systems with elevated SFR surface
densities, especially when there has been a recent upturn in the star formation
activity according to the SFR/SFR parameter. We find the
ionized outflow kinematics to be in line with what we measure in the neutral
phase. This demonstrates that, despite their small contributions to the total
outflow mass budget, there is value to collecting empirical measurements of the
ionized wind phase to provide information on the bulk motion in the outflow.
Depending on dust corrections applied to the ionized gas diagnostics, the
neutral phase has dex higher mass outflow rates
(), on average, compared to the ionized phase. We quantify
scaling relations between and the strengths of the physical
wind drivers (SFR, ). Using a radial-azimuthal stacking method, and by
considering inclination dependencies, we find results consistent with biconical
outflows orthogonal to the disk plane. Our work complements other multi-phase
outflow studies in the literature which consider smaller samples, more extreme
objects, or proceed via stacking of larger samples.Comment: This is a pre-copyedited, author-produced PDF of an article accepted
for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
following peer revie
Selective Cholesterol Dynamics between Lipoproteins and Caveolae/Lipid Rafts
Although low-density lipoprotein (LDL) receptor-mediated cholesterol uptake through clathrin-coated pits is now well understood, the molecular details and organizing principles for selective cholesterol uptake/efflux (reverse cholesterol transport, RCT) from peripheral cells remain to be resolved. It is not yet completely clear whether RCT between serum lipoproteins and the plasma membrane occurs primarily through lipid rafts/caveolae or from non-raft domains. To begin to address these issues, lipid raft/caveolae-, caveolae-, and non-raft-enriched fractions were resolved from purified plasma membranes isolated from L-cell fibroblasts and MDCK cells by detergent-free affinity chromatography and compared with detergent-resistant membranes isolated from the same cells. Fluorescent sterol exchange assays between lipoproteins (VLDL, LDL, HDL, apoA1) and these enriched domains provided new insights into supporting the role of lipid rafts/caveolae and caveolae in plasma membrane/lipoprotein cholesterol dynamics: (i) lipids known to be translocated through caveolae were detected (cholesteryl ester, triacylglycerol) and/or enriched (cholesterol, phospholipid) in lipid raft/caveolae fractions; (ii) lipoprotein-mediated sterol uptake/efflux from lipid rafts/caveolae and caveolae was rapid and lipoprotein specific, whereas that from non-rafts was very slow and independent of lipoprotein class; and (iii) the rate and lipoprotein specificity of sterol efflux from lipid rafts/caveolae or caveolae to lipoprotein acceptors in vitro was slower and differed in specificity from that in intact cellsconsistent with intracellular factors contributing significantly to cholesterol dynamics between the plasma membrane and lipoproteins
Service evaluation of weight outcomes as a function of initial BMI in 34,271 adults referred to a primary care/commercial weight management partnership scheme
Peer reviewedPublisher PD
Agroecology: promoting the transition towards sustainability
En este artículo se define agroecología como la aplicación de los
conceptos y prinicipios ecológicos al diseño y manejo de los sistemas alimentarios sostenibles. Se presentan los argumentos principales que
sostienen la validez, importancia y pertinencia del enfoque agroecológico, no solo para entender los procesos involucrados en la producción
de alimentos, sino para proponer alternativas que conduzcan a esos procesos para operar en sistemas sostenibles. El concepto clave, que
guía el razonamiento metodológico y epistemológico en este análisis, es el de sostenibilidad. Para alcanzar sostenibilidad la metodología
agroecológica no solo se ancla en la Ecología, lo cual se describe en el trabajo, sino que percibe la producción de alimentos como un
proceso que involucra a los productores y consumidores interactuando en forma dinámica.In this article agroecology is defined as the application of ecological
concepts and principles to the design and management of sustainable food systems. The principal arguments are presented that support the
validity, importance, and application of the agroecologial focus, not only in order to understand the processes involved in food production, but
also to propose alternatives that help these processes to operate in sustainable systems. The key concept that guides the methodological
and epitistemalogical rationale of this analysis is sustainability. In order to achieve sustainability the agroecological methodology not only links
to Ecology, as is described in the text, but perceives food production as a process involving producers and consumers operating in a
dynamic interaction
- …