9,236 research outputs found
Forager bees (Apis mellifera) highly express immune and detoxification genes in tissues associated with nectar processing.
Pollinators, including honey bees, routinely encounter potentially harmful microorganisms and phytochemicals during foraging. However, the mechanisms by which honey bees manage these potential threats are poorly understood. In this study, we examine the expression of antimicrobial, immune and detoxification genes in Apis mellifera and compare between forager and nurse bees using tissue-specific RNA-seq and qPCR. Our analysis revealed extensive tissue-specific expression of antimicrobial, immune signaling, and detoxification genes. Variation in gene expression between worker stages was pronounced in the mandibular and hypopharyngeal gland (HPG), where foragers were enriched in transcripts that encode antimicrobial peptides (AMPs) and immune response. Additionally, forager HPGs and mandibular glands were enriched in transcripts encoding detoxification enzymes, including some associated with xenobiotic metabolism. Using qPCR on an independent dataset, we verified differential expression of three AMP and three P450 genes between foragers and nurses. High expression of AMP genes in nectar-processing tissues suggests that these peptides may contribute to antimicrobial properties of honey or to honey bee defense against environmentally-acquired microorganisms. Together, these results suggest that worker role and tissue-specific expression of AMPs, and immune and detoxification enzymes may contribute to defense against microorganisms and xenobiotic compounds acquired while foraging
The use of animal models to study cell transplantation in neuropathic hearing loss
Auditory neuropathy (AN) is a form of sensorineural deafness specifically affecting the conduction of the nerve impulse from the cochlear hair cells to the auditory centres of the brain. As such, the condition is a potential clinical target for ‘cell replacement therapy’, in which a functioning auditory nerve is regenerated by transplanting an appropriated neural progenitor.
In this review, we survey the current literature and examine possible experimental models for this condition, with particular reference to their compatibility as suitable hosts for transplantation. The use of exogenous neurotoxic agents such as ouabain or β-bungarotoxin is discussed, as are ageing and noise-induced synaptopathy models. Lesioning of the nerve by mechanical damage during surgery and the neuropathy resulting from infectious diseases may be very relevant clinically, and we discuss whether there are good models for these situations. We also address genetic models for AN, examining whether the phenotypes truly model the clinical situation in their human counterpart syndromes - we use the example of the hyperbilirubinaemic Gunn rat as a particular instance in this regard
The form factors from Analyticity and Unitarity
Analyticity and unitarity techniques are employed to obtain bounds on the
shape parameters of the scalar and vector form factors of semileptonic
decays. For this purpose we use vector and scalar correlators evaluated in
pQCD, a low energy theorem for scalar form factor, lattice results for the
ratio of kaon and pion decay constants, chiral perturbation theory calculations
for the scalar form factor at the Callan-Treiman point and experimental
information on the phase and modulus of form factors up to an energy
\tin=1 {\rm GeV}^2. We further derive regions on the real axis and in the
complex-energy plane where the form factors cannot have zeros.Comment: 6 pages, 5 figures; Seminar given at DAE-BRNS Workshop on Hadron
Physics Bhabha Atomic Research Centre, Mumbai, India October 31-November 4,
2011, submitted to Proceeding
Linear Relationship Statistics in Diffusion Limited Aggregation
We show that various surface parameters in two-dimensional diffusion limited
aggregation (DLA) grow linearly with the number of particles. We find the ratio
of the average length of the perimeter and the accessible perimeter of a DLA
cluster together with its external perimeters to the cluster size, and define a
microscopic schematic procedure for attachment of an incident new particle to
the cluster. We measure the fractal dimension of the red sites (i.e., the sites
upon cutting each of them splits the cluster) equal to that of the DLA cluster.
It is also shown that the average number of the dead sites and the average
number of the red sites have linear relationships with the cluster size.Comment: 4 pages, 5 figure
Diagnosis and Management of Ureterovaginal Fistula in a Resource-Constrained Setting: Experience at a District Hospital in Northern Nigeria
During 2007 we were invited at different times to review and manage four women with ureterovaginal fistula following caesarean section performed in different rural hospitals. We describe our experience of a simple technique of diagnosis and management of these indigent patients in a resourceconstrained hospital. The condition was diagnosed by the three-swab test in all four patients, and abdominopelvic ultrasound was employed to help find the ureter involved. Transvesical ureteral implantation with a stent was carried out. Stent was removed after 2 weeks. All four patients were dry. Amidst the complexity of and sophistication of modern health care, it is important to remind ourselves of the common occurrence of this distressing condition following caesarean section and the use of a
well known simple diagnostic technique and subsequent management in resource-poor communities Keywords: Ureterovaginal fistula, Caesarean section, Resource constrained Libyan Medical Journal Vol. 4 (1) 2009: pp. 45-4
Unstable Disk Galaxies. I. Modal Properties
I utilize the Petrov-Galerkin formulation and develop a new method for
solving the unsteady collisionless Boltzmann equation in both the linear and
nonlinear regimes. In the first order approximation, the method reduces to a
linear eigenvalue problem which is solved using standard numerical methods. I
apply the method to the dynamics of a model stellar disk which is embedded in
the field of a soft-centered logarithmic potential. The outcome is the full
spectrum of eigenfrequencies and their conjugate normal modes for prescribed
azimuthal wavenumbers. The results show that the fundamental bar mode is
isolated in the frequency space while spiral modes belong to discrete families
that bifurcate from the continuous family of van Kampen modes. The population
of spiral modes in the bifurcating family increases by cooling the disk and
declines by increasing the fraction of dark to luminous matter. It is shown
that the variety of unstable modes is controlled by the shape of the dark
matter density profile.Comment: Accepted for publication in The Astrophysical Journa
Spectral characteristics of normal and nutrient-deficient maize leaves
Reflectance, transmittance and absorbance spectra of normal and six types of mineral-deficient (N,P,K,S,Mg and Ca) maize (Zea mays L.) leaves were analyzed at 30 selected wavelengths along the electromagnetic spectrum from 500 to 2600 nm. Chlorophyll content and percent leaf moisture were also determined. Leaf thermograms were obtained for normal, N- and S- deficient leaves. The results of the analysis of variance showed significant differences in reflectance, transmittance and absorbance in the visible wavelengths among leaf numbers 3, 4, and 5, among the seven nutrient treatments, and among the interactions of leaves and treatments. In the reflective infrared wavelengths only treatments produced significant differences. The chlorophyll content of leaves was reduced in all deficiencies in comparison to controls. Percent moisture was increased in S-, Mg- and N- deficiencies. Positive correlation (r = 0.707) between moisture content and percent absorption at both 1450 and 1930 nm were obtained. Polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related (r = 0.894)
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