2,118 research outputs found
A mutation in amino acid permease AAP6 reduces the amino acid content of the Arabidopsis sieve elements but leaves aphid herbivores unaffected
The aim of this study was to investigate the role of the amino acid permease gene AAP6 in regulating phloem amino acid composition and then to determine the effects of this altered diet on aphid performance. A genotype of Arabidopsis thaliana (L.) was produced in which the function of the amino acid permease gene AAP6 (At5g49630) was abolished. Plants homozygous for the insertionally inactivated AAP6 gene had a significantly larger mean rosette width than the wild type and a greater number of cauline leaves. Seeds from the aap6 mutant were also significantly larger than those from the wild-type plants. Sieve element (SE) sap was collected by aphid stylectomy and the amino acids derivatized, separated, and quantified using Capillary Electrophoresis with Laser Induced Fluorescence (CE-LIF). In spite of the large variation across samples, the total amino acid concentration of SE sap of the aap6 mutant plants was significantly lower than that of the wild-type plants. The concentrations of lysine, phenylalanine, leucine, and aspartic acid were all significantly lower in concentration in the aap6 mutant plants compared with wild-type plants. This is the first direct demonstration of a physiological role for an amino acid transporter in regulating SE composition in vivo. The amino acid availability in sieve element sap is thought to be the major limiting factor for aphid growth and reproduction. Despite the changes in their diet, the aphid Myzus persicae (Sulzer) displayed only small changes in feeding behaviour on mutant plants when measured using the Electronic Penetration Graph (EPG) technique. Salivation by the aphid into the SE (E1 phase) was increased on mutant plants but there was no significant effect on other feeding EPG behaviours, or in the rate of honeydew production. Consistent with the small effect on aphid feeding behaviour, there was only a small effect of reduced sieve element amino acid concentration on aphid reproduction. The data are discussed in relation to the regulation of phloem composition and the role of phloem amino acids in regulating aphid performance
Not in my back yard! Sports stadia location and the property market
In recent years sports stadia have been built in the UK, not only for their intended sporting purpose but with the twin aim of stimulating economic and physical regeneration. However, proposals to locate stadia in urban areas often prompt a negative reaction from local communities, fearing a decline in property prices. This paper will use a case study of the Millennium Stadium in Cardiff and the City of Manchester Stadium to illustrate that in contrast to this widely held belief, sports stadia can actually enhance the value of residential property. Furthermore, it will argue that stadia also contribute indirectly to property value through the creation of pride, confidence and enhanced image of an area.</p
Investigation of the magnetic field characteristics of Herbig Ae/Be stars: Discovery of the pre-main sequence progenitors of the magnetic Ap/Bp stars
We are investigating the magnetic characteristics of pre-main sequence Herbig
Ae/Be stars, with the aim of (1) understanding the origin and evolution of
magnetism in intermediate-mass stars, and (2) exploring the influence of
magnetic fields on accretion, rotation and mass-loss at the early stages of
evolution of A, B and O stars. We have begun by conducting 2 large surveys of
Herbig Ae/Be stars, searching for direct evidence of photospheric magnetic
fields via the longitudinal Zeeman effect. From observations obtained using
FORS1 at the ESO-VLT and ESPaDOnS at the Canada-France-Hawaii Telescope, we
report the confirmed detection of magnetic fields in 4 pre-main sequence A- and
B-type stars, and the apparent (but as yet unconfirmed) detection of fields in
2 other such stars. We do not confirm the detection of magnetic fields in
several stars reported by other authors to be magnetic: HD 139614, HD 144432 or
HD 31649. One of the most evolved stars in the detected sample, HD 72106A,
shows clear evidence of strong photospheric chemical peculiarity, whereas many
of the other (less evolved) stars do not. The magnetic fields that we detect
appear to have surface intensities of order 1 kG, seem to be structured on
global scales, and appear in about 10% of the stars studied. Based on these
properties, these magnetic stars appear to be pre-main sequence progenitors of
the magnetic Ap/Bp stars.Comment: v2: Include comment regarding publication source To appear in the
proceedings of "Solar Polarisation 4", held in Boulder, USA, Sept. 200
Immigration into the mainstream: Conflicting ideological streams, strategic reasoning and party competition
A nutritional intervention against Covid-19: Possibilities on the use of an alkaline diet to boost physiological resistance and immunity
158-163Novel Coronavirus (2019-nCoV) is a causative agent of COVID-19. The perilous pandemic caused by 2019-nCoV erupted in late 2019 in China has blanketed the whole world and continues to do so. The incidence of the disease, its morbidity, and mortality is high. Strategic planning to contain a virus, fast track research for prophylactics and therapeutics are underway. Food is one of the components of complementary and alternative medicine of the cultures all over the world. Routine diet and its management which is an easily manageable affair will also play crucial to improve an individual’s resistance to infection. In recent years alkaline diet has secured a large number of proponents and gained popularity among the scientific community as well. Its significance for the treatment of many non-communicable diseases has been recognized. The diet or food component whose net potential renal acid load (PRAL) is low is defined as an alkaline diet. We hypothesize that the alkaline diet could significantly boost an individual’s physiological resistance and immunity against 2019-nCoV by targeting endosomal pH which plays an important role in viral pathogenesis. Hydroxychloroquine, a therapeutic drug that is being used at present for COVID-19 treatment also targets endosomal pH to viral prevent infection. In the present article, we have discussed the significance of diet in traditional medicine, pH homeostasis, the role of pH in 2019-nCoV pathogenesis and the possibilities of how the alkaline diet could interfere with the initial stages of infection. Clinical evidences of the use of the alkaline diet for the treatment of infectious and non-infectious diseases have been reviewed. Further, technical details of the alkaline diet, its correlation to Ayurvedic dietetics have been discussed. Though the current article emphasizes the management of the COVID-19 in the light of pandemic, the approach holds grounds for the other respiratory tract viral pathogens too whose pathogenesis is similar to 2019-nCoV. Future experimental studies to establish such correlation are warranted. Adopting the food which has low dietary acid load (alkaline diet) will aid in boosting the physiological resistance resulting in improved health conditions to fight against 2019-nCoV
Characterization of methicillin-resistant Staphylococcus aureus isolates from apparently healthy individuals in Malete, Kwara state, Nigeria
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common and continuously growing cause of nosocomial and community-acquired staphylococcal infections around the world. Screening for colonization with MRSA is a major aspect of control and limiting the spread of infections cause by this organism. We investigated the carriage of MRSA among apparently healthy individuals in four rural villages: Eleburu, Tapa, Atere and Apo all around semi-urban town-Malete, in Moro Local Government of Kwara State, Nigeria.Methods: Nasal swabs were collected from volunteered individuals and were cultured on mannitol salt agar and blood agar for isolation and identification of Staph aureus using standard microbiological techniques. Susceptibility to cefoxitin disc (30 ag) was used to determine MRSA status of the isolates. Molecular method was used to detect the gene responsible for resistance among MRSA isolates. Antimicrobial susceptibility test to commonly prescribed antibiotics was carried out using discs diffusion method.Results: Total number of individuals carrying Staph aureus in their nostrils was 42 (37.2 %). Antibiotics susceptibility profile of Staph aureus isolates showed 100 % resistance to cefuroxime, cefotaxime, cloxacillin and augmentin, and were 87 %, 81 %, 69 % and 23.8 % and 19 % resistant to tetracycline, ceftriaxone, erythromycin, ofloxacin and gentamicin respectively. A total of 6 (14%) Community âAcquired MRSA (CA-MRSA) isolates were recovered from individuals living in these villages. Molecular method detected muc and mecA genes in all the 6 (100%) CA-MRSA isolates and lukS-lukF was detected in 3 (50%) of the isolates.Conclusion: Detection of CA-MRSA strains among these rural dweller indicates that they are harbouring enhance virulence organism that may manifest a more severe disease condition. The danger associated with high prevalence of multidrug resistant Staph aureus and CAMRSA; and its consequential effects of poor drug administration in Nigeria was discussed. There is need to establish a more strict legislation and enforcement on drug control; and a body that would monitor production and appropriate use of antibiotics in the Nigeria.KEYWORDS: CA-MRSA, Staph aureus, Antibiotics, Rural Villages and Molecular Characterizatio
The scattering from generalized Cantor fractals
We consider a fractal with a variable fractal dimension, which is a
generalization of the well known triadic Cantor set. In contrast with the usual
Cantor set, the fractal dimension is controlled using a scaling factor, and can
vary from zero to one in one dimension and from zero to three in three
dimensions. The intensity profile of small-angle scattering from the
generalized Cantor fractal in three dimensions is calculated. The system is
generated by a set of iterative rules, each iteration corresponding to a
certain fractal generation. Small-angle scattering is considered from
monodispersive sets, which are randomly oriented and placed. The scattering
intensities represent minima and maxima superimposed on a power law decay, with
the exponent equal to the fractal dimension of the scatterer, but the minima
and maxima are damped with increasing polydispersity of the fractal sets. It is
shown that for a finite generation of the fractal, the exponent changes at
sufficiently large wave vectors from the fractal dimension to four, the value
given by the usual Porod law. It is shown that the number of particles of which
the fractal is composed can be estimated from the value of the boundary between
the fractal and Porod regions. The radius of gyration of the fractal is
calculated analytically.Comment: 8 pages, 4 figures, accepted for publication in J. Appl. Crys
Global gene expression of histologically normal primary skin cells from BCNS subjects reveals "single-hit" effects that are influenced by rapamycin
Studies of dominantly heritable cancers enabled insights about tumor progression. BCNS is a dominantly inherited disorder that is characterized by developmental abnormalities and postnatal neoplasms, principally BCCs. We performed an exploratory gene expression profiling of primary cell cultures derived from clinically unaffected skin biopsies of BCNS gene-carriers (PTCH1 +/-) and normal individuals. PCA and HC of untreated keratinocytes or fibroblasts failed to clearly distinguish BCNS samples from controls. These results are presumably due to the common suppression of canonical HH signaling in vitro. We then used a relaxed threshold (p-value <0.05, no FDR cut-off; FC 1.3) that identified a total of 585 and 857 genes differentially expressed in BCNS keratinocytes and fibroblasts samples, respectively. A GSEA identified pancreatic ÎČ cell hallmark and mTOR signaling genes in BCNS keratinocytes, whereas analyses of BCNS fibroblasts identified gene signatures regulating pluripotency of stem cells, including WNT pathway. Significantly, rapamycin treatment (FDR<0.05), affected a total of 1411 and 4959 genes in BCNS keratinocytes and BCNS fibroblasts, respectively. In contrast, rapamycin treatment affected a total of 3214 and 4797 genes in normal keratinocytes and normal fibroblasts, respectively. The differential response of BCNS cells to rapamycin involved 599 and 1463 unique probe sets in keratinocytes and fibroblasts, respectively. An IPA of these genes in the presence of rapamycin pointed to hepatic fibrosis/stellate cell activation, and HIPPO signaling in BCNS keratinocytes, whereas mitochondrial dysfunction and AGRN expression were uniquely enriched in BCNS fibroblasts. The gene expression changes seen here are likely involved in the etiology of BCCs and they may represent biomarkers/targets for early intervention
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Solar Energetic Particles Produced by a Slow Coronal Mass Ejection at âŒ0.25 au
We present an analysis of Parker Solar Probe (PSP) ISâIS observations of ~30â300 keV nâ»Âč ions on 2018 November 11 when PSP was about 0.25 au from the Sun. Five hours before the onset of a solar energetic particle (SEP) event, a coronal mass ejection (CME) was observed by STEREO-A/COR2, which crossed PSP about a day later. No shock was observed locally at PSP, but the CME may have driven a weak shock earlier. The SEP event was dispersive, with higher energy ions arriving before the lower energy ones. Timing suggests the particles originated at the CME when it was at ~7.4R_â. SEP intensities increased gradually from their onset over a few hours, reaching a peak, and then decreased gradually before the CME arrived at PSP. The event was weak, having a very soft energy spectrum (â4 to â5 spectral index). The earliest arriving particles were anisotropic, moving outward from the Sun, but later, the distribution was observed to be more isotropic. We present numerical solutions of the Parker transport equation for the transport of 30â300 keV nâ»Âč ions assuming a source comoving with the CME. Our model agrees well with the observations. The SEP event is consistent with ion acceleration at a weak shock driven briefly by the CME close to the Sun, which later dissipated before arriving at PSP, followed by the transport of ions in the interplanetary magnetic field
Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe
A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (ISâIS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly close to the source. The event was very small, with peak 1 MeV proton intensities of ~0.3 particles (cmÂČ sr s MeV)â»Âč, and was undetectable above background levels at energies above 10 MeV or in particle detectors at 1 au. It was strongly anisotropic, with intensities flowing outward from the Sun up to 30 times greater than those flowing inward persisting throughout the event. Temporal association between particle increases and small brightness surges in the extreme-ultraviolet observed by the Solar TErrestrial RElations Observatory, which were also accompanied by type III radio emission seen by the Electromagnetic Fields Investigation on PSP, indicates that the source of this event was an active region nearly 80° east of the nominal PSP magnetic footpoint. This suggests that the field lines expanded over a wide longitudinal range between the active region in the photosphere and the corona
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