3,609 research outputs found
Benchmarking vector arthropod culture: an example using the African malaria mosquito, Anopheles gambiae (Diptera: Culicidae)
BACKGROUND: Numerous important characteristics of adult arthropods are related to their size; this is influenced by conditions experienced as immatures. Arthropods cultured in the laboratory for research, or mass-reared for novel control methods, must therefore be of a standard size range and known quality so that results are reproducible. METHODS: A simple two-step technique to assess laboratory culture methods was demonstrated using the mosquito Anopheles gambiae s.s. as a model. First, the ranges of key development outcomes were determined using various diet levels. The observed outcomes described the physiologically constrained limits. Secondly, the same outcomes were measured when using a standard operating procedure (SOP) for comparison with the determined ranges. RESULTS: The standard method resulted in similar development rates to those of high and medium diets, wing length between those resulting from the high and medium diets, and larval survival exceeding all benchmark diet level values. The SOP used to produce experimental material was shown to produces high-quality material, relative to the biologically constrained limits. CONCLUSIONS: The comparison between all possible phenotypic outcomes, as determined by biological constraints, with those outcomes obtained using a given rearing protocol is termed âbenchmarkingâ. A method is here demonstrated which could be easily adapted to other arthropods, to objectively assess important characters obtained, and methods used, during routine culture that may affect outcomes of research. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1288-4) contains supplementary material, which is available to authorized users
Benchmarking vector arthropod culture: an example using the African malaria mosquito, Anopheles gambiae (Diptera: Culicidae)
Background: Numerous important characteristics of adult arthropods are related to their size; this is influenced by conditions experienced as immatures. Arthropods cultured in the laboratory for research, or mass-reared for novel control methods, must therefore be of a standard size range and known quality so that results are reproducible.Methods: A simple two-step technique to assess laboratory culture methods was demonstrated using the mosquito Anopheles gambiae s.s. as a model. First, the ranges of key development outcomes were determined using various diet levels. The observed outcomes described the physiologically constrained limits. Secondly, the same outcomes were measured when using a standard operating procedure (SOP) for comparison with the determined ranges.Results: The standard method resulted in similar development rates to those of high and medium diets, wing length between those resulting from the high and medium diets, and larval survival exceeding all benchmark diet level values. The SOP used to produce experimental material was shown to produces high-quality material, relative to the biologically constrained limits.Conclusions: The comparison between all possible phenotypic outcomes, as determined by biological constraints, with those outcomes obtained using a given rearing protocol is termed âbenchmarkingâ. A method is here demonstrated which could be easily adapted to other arthropods, to objectively assess important characters obtained, and methods used, during routine culture that may affect outcomes of research
PCV13 induced IgG responses in serum associate with serotype-specific IgG in the lung
Pneumococcal conjugate vaccine efficacy is lower for non-invasive pneumonia than invasive disease. In this study, participants were vaccinated with PCV13 or HepA (control). Bronchoalveolar lavage samples were taken between 2-6 months and serum at 4- and 7-weeks post vaccination. In the lung, anti-capsular IgG levels were higher in the PCV13 group compared to control for all serotypes, except 3 and 6B. Systemically, IgG levels were elevated in the PCV group at 4-weeks for all serotypes, except 3. IgG in BAL and serum positively correlated for nearly all serotypes. PCV13 shows poor immunogenicity to serotype 3, implying lack of protective efficacy.
Clinical trial registration with ISRCTN: 4534043
VirusâHost Interactions Between Nonsecretors and Human Norovirus
BACKGROUND & AIMS: Human norovirus infection is the leading
cause of acute gastroenteritis. Genetic polymorphisms, mediated
by the FUT2 gene (secretor enzyme), define strain susceptibility.
Secretors express a diverse set of fucosylated histoblood group
antigen carbohydrates (HBGA) on mucosal cells; nonsecretors
(FUT2-/-) express a limited array of HBGAs. Thus, nonsecretors
have less diverse norovirus strain infections, including resistance
to the epidemiologically dominant GII.4 strains. Because future
human norovirus vaccines will comprise GII.4 antigen and because
secretor phenotype impacts GII.4 infection and immunity, nonsecretors may mimic young children immunologically in response
to GII.4 vaccination, providing a needed model to study crossprotection in the context of limited pre-exposure.
METHODS: By using specimens collected from the first characterized nonsecretor cohort naturally infected with GII.2
human norovirus, we evaluated the breadth of serologic immunity by surrogate neutralization assays, and cellular activation and cytokine production by flow cytometry.
RESULTS: GII.2 infection resulted in broad antibody and
cellular immunity activation that persisted for at least 30 days
for T cells, monocytes, and dendritic cells, and for 180 days for
blocking antibody. Multiple cellular lineages expressing interferon-g and tumor necrosis factor-a dominated the response.
Both T-cell and B-cell responses were cross-reactive with other
GII strains, but not GI strains. To promote entry mechanisms,
inclusion of bile acids was essential for GII.2 binding to
nonsecretor HBGAs.
CONCLUSIONS: These data support development of withingenogroup, cross-reactive antibody and T-cell immunity, key
outcomes that may provide the foundation for eliciting broad
immune responses after GII.4 vaccination in individuals with
limited GII.4 immunity, including young children
Two-Minute k-Space and Timeâaccelerated Aortic Four-dimensional Flow MRI: Dual-Center Study of Feasibility and Impact on Velocity and Wall Shear Stress Quantification
PURPOSE: To investigate the two-center feasibility of highly k-space and time (k-t)âaccelerated 2-minute aortic four-dimensional (4D) flow MRI and to evaluate its performance for the quantification of velocities and wall shear stress (WSS).
MATERIALS AND METHODS: This cross-sectional study prospectively included 68 participants (center 1, 11 healthy volunteers [mean age ± standard deviation, 61 years ± 15] and 16 patients with aortic disease [mean age, 60 years ± 10]; center 2, 14 healthy volunteers [mean age, 38 years ± 13] and 27 patients with aortic or cardiac disease [mean age, 78 years ± 18]). Each participant underwent highly accelerated 4D flow MRI (k-t acceleration, acceleration factor of 5) of the thoracic aorta. For comparison, conventional 4D flow MRI (acceleration factor of 2) was acquired in the participants at center 1 (n = 27). Regional aortic peak systolic velocities and three-dimensional WSS were quantified.
RESULTS: k-tâaccelerated scan times (center 1, 2:03 minutes ± 0:29; center 2, 2:06 minutes ± 0:20) were significantly reduced compared with conventional 4D flow MRI (center 1, 12:38 minutes ± 2:25; P < .0001). Overall good agreement was found between the two techniques (absolute differences â€15%), but proximal aortic WSS was significantly underestimated in patients by using k-tâaccelerated 4D flow when compared with conventional 4D flow (P †.03). k-tâaccelerated 4D flow MRI was reproducible (intra- and interobserver intraclass correlation coefficient â„0.98) and identified significantly increased peak velocities and WSS in patients with stenotic (P †.003) or bicuspid (P †.04) aortic valves compared with healthy volunteers. In addition, k-tâaccelerated 4D flow MRIâderived velocities and WSS were inversely related to age (r â„â0.53; P †.03) over all healthy volunteers.
CONCLUSION: k-tâaccelerated aortic 4D flow MRI providing 2-minute scan times was feasible and reproducible at two centers. Although consistent healthy aging- and disease-related changes in aortic hemodynamics were observed, care should be taken when considering WSS, which can be underestimated in patients
Multi-lepton signals from the top-prime quark at the LHC
We analyze the collider signatures of models with a vector-like top-prime
quark and a massive color-octet boson. The top-prime quark mixes with the top
quark in the Standard Model, leading to richer final states than ones that are
investigated by experimental collaborations. We discuss the multi-lepton final
states, and show that they can provide increased sensitivity to models with a
top-prime quark and gluon-prime. Searches for new physics in high multiplicity
events are an important component of the LHC program and complementary to
analyses that have been performed.Comment: 7 pages, 4 figures, 2 table
The Atmospheric Coupling and Dynamics Across the Mesopause (ACaDAMe) mission
The Atmospheric Coupling and Dynamics Across the Mesopause (ACaDAMe) is a mission designed to uniquely address critical questions involving multi-scale wave dynamics at key space weather (SWx) âgateway altitudesâ of the mesosphere and lower thermosphere (MLT) at âŒ70â150âŻkm. ACaDAMe observes with a nadir-pointing resonant lidar that utilizes the fluorescence of atomic Na present in the MLT. By tuning a laser to the Na absorption wavelength (589âŻnm), ACaDAMe would perform very high resolution measurements of temperature and Na densities across the mesopause during both day and night. In this manner, Na is used as tracer for observing and characterizing MLT waves generated by tropospheric weather that represent the dominant terrestrial source of energy and momentum affecting space weather and transport of mesospheric species
Implications of a High-Mass Diphoton Resonance for Heavy Quark Searches
Heavy vector-like quarks coupled to a scalar will induce a coupling of
this scalar to gluons and possibly (if electrically charged) photons. The decay
of the heavy quark into , with being a Standard Model quark, provides,
if kinematically allowed, new channels for heavy quark searches. Inspired by
naturalness considerations, we consider the case of a vector-like partner of
the top quark. For illustration, we show that a singlet partner can be searched
for at the 13TeV LHC through its decay into a scalar resonance in the
final states, especially if the diphoton branching ratio of
the scalar is further enhanced by the contribution of non coloured
particles. We then show that conventional heavy quark searches are also
sensitive to this new decay mode, when decays hadronically, by slightly
tightening the current selection cuts. Finally, we comment about the
possibility of disentangling, by scrutinising appropriate kinematic
distributions, heavy quark decays to from other standard decay modes.Comment: 8 pages, 3 figures and 1 table; v3: typos fixed. Matches published
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Proteomics of synapse
Large-scale phosphoproteome analysis on synaptosome and preparation of post-synaptic density (PSD) were investigated. It was found that protein phosphor is a common event in the synapse, which is consistent with the presence of diverse classes of kinases and phosphatases in the synapse. Synaptic proteomics analysis required the purification of subcellular organelles from the brain regions of interest. Multiple steps of discontinuous density gradient ultra-centrifugation were employed to enrich the distinct organelles. Two-dimensional gel electrophoresis was used to separate and quantify proteins, including post-translational modified forms, from synaptic structures. It was observed that proteomic analysis of the synaptic vesicle identified 36 proteins, including seven integral membrane proteins and vesicle regulatory proteins
Normal levels of p27Xic1 are necessary for somite segmentation and determining pronephric organ size
The Xenopus laevis cyclin dependent kinase inhibitor p27Xic1 has been shown to be involved in exit from the cell cycle and differentiation of cells into a quiescent state in the nervous system, muscle tissue, heart and retina. We show that p27Xic1 is expressed in the developing kidney in the nephrostomal regions. Using over-expression and morpholino oligonucleotide (MO) knock-down approaches we show normal levels of p27Xic1 regulate pronephros organ size by regulating cell cycle exit. Knock-down of p27Xic1 expression using a MO prevented myogenesis, as previously reported; an effect that subsequently inhibits pronephrogenesis. Furthermore, we show that normal levels of p27Xic1 are required for somite segmentation also through its cell cycle control function. Finally, we provide evidence to suggest correct paraxial mesoderm segmentation is not necessary for pronephric induction in the intermediate mesoderm. These results indicate novel developmental roles for p27Xic1, and reveal its differentiation function is not universally utilised in all developing tissues
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