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61.
Mishra PK Wu W Rozo C Hallab NJ Benevenia J Gause WC 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(12):6491-6498
Wear debris in joint replacements has been suggested as a cause of associated tissue-damaging inflammation. In this study, we examined whether solid titanium microparticles (mTi) of sufficient size to accumulate as wear debris could stimulate innate or adaptive immunity in vivo. mTi, administered in conjunction with OVA, promoted total and Ag-specific elevations in serum IgE and IgG1. Analysis of transferred transgenic OVA-specific naive T cells further showed that mTi acted as an adjuvant to drive Ag-specific Th2 cell differentiation in vivo. Assessment of the innate response indicated that mTi induced rapid recruitment and differentiation of alternatively activated macrophages in vivo, through IL-4- and TLR4-independent pathways. These studies suggest that solid microparticles alone can act as adjuvants to induce potent innate and adaptive Th2-type immune responses and further suggest that wear debris in joint replacements may have Th2-type inflammatory properties. 相似文献
62.
63.
How do species barriers decay? Concordance and local introgression in mosaic hybrid zones of mussels
Alexis Simon Christelle Fraïsse Tahani El Ayari Cathy Liautard‐Haag Petr Strelkov John J. Welch Nicolas Bierne 《Journal of evolutionary biology》2021,34(1):208-223
The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study ‘replicated’ instances of secondary contact between closely related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry‐informative panel of such SNPs. We then compared their frequencies in newly sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi‐stable variants (Dobzhansky‐Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact. 相似文献
64.
The large number of variables involved in many biophysical models can conceal potentially simple dynamical mechanisms governing
the properties of its solutions and the transitions between them as parameters are varied. To address this issue, we extend
a novel model reduction method, based on “scales of dominance,” to multi-compartment models. We use this method to systematically
reduce the dimension of a two-compartment conductance-based model of a crustacean pyloric dilator (PD) neuron that exhibits
distinct modes of oscillation—tonic spiking, intermediate bursting and strong bursting. We divide trajectories into intervals
dominated by a smaller number of variables, resulting in a locally reduced hybrid model whose dimension varies between two
and six in different temporal regimes. The reduced model exhibits the same modes of oscillation as the 16 dimensional model
over a comparable parameter range, and requires fewer ad hoc simplifications than a more traditional reduction to a single,
globally valid model. The hybrid model highlights low-dimensional organizing structure in the dynamics of the PD neuron, and
the dependence of its oscillations on parameters such as the maximal conductances of calcium currents. Our technique could
be used to build hybrid low-dimensional models from any large multi-compartment conductance-based model in order to analyze
the interactions between different modes of activity. 相似文献
65.
Nicolas Marsollier Nadim Kassis Karima Mezghenna Maud Soty Xavier Fioramonti Amélie Lacombe Aurélie Joly Bruno Pillot Carine Zitoun José Vilar Gilles Mithieux René Gross Anne-Dominique Lajoix Vanessa Routh Christophe Magnan Céline Cruciani-Guglielmacci 《PloS one》2009,4(8)
Background
Deregulation of hypothalamic fatty acid sensing lead to hepatic insulin-resistance which may partly contribute to further impairment of glucose homeostasis.Methodology
We investigated here whether hypothalamic nitric oxide (NO) could mediate deleterious peripheral effect of central lipid overload. Thus we infused rats for 24 hours into carotid artery towards brain, either with heparinized triglyceride emulsion (Intralipid, IL) or heparinized saline (control rats).Principal Findings
Lipids infusion led to hepatic insulin-resistance partly related to a decreased parasympathetic activity in the liver assessed by an increased acetylcholinesterase activity. Hypothalamic nitric oxide synthases (NOS) activities were significantly increased in IL rats, as the catalytically active neuronal NOS (nNOS) dimers compared to controls. This was related to a decrease in expression of protein inhibitor of nNOS (PIN). Effect of IL infusion on deregulated hepatic insulin-sensitivity was reversed by carotid injection of non selective NOS inhibitor NG-monomethyl-L-arginine (L-NMMA) and also by a selective inhibitor of the nNOS isoform, 7-Nitro-Indazole (7-Ni). In addition, NO donor injection (L-arginine and SNP) within carotid in control rats mimicked lipid effects onto impaired hepatic insulin sensitivity. In parallel we showed that cultured VMH neurons produce NO in response to fatty acid (oleic acid).Conclusions/Significance
We conclude that cerebral fatty acid overload induces an enhancement of nNOS activity within hypothalamus which is, at least in part, responsible fatty acid increased hepatic glucose production. 相似文献66.
Maryline Paris Catherine Bernard-Kargar José Vilar Nadim Kassis Alain Ktorza 《Experimental diabetes research》2004,5(4):257-263
We investigated the possible interplay between insulin
and glucose signaling pathways in rat pancreatic β-cell
with a special focus on the role of glucose in IRS signaling
in vivo. Three groups of rats were constituted by combining
simultaneous infusion during 48 h either of glucose
and/or insulin, or glucose+diazoxide: Hyperglycemic-
Hyperinsulinemic (HGHI), euglycemic-Hyperinsulinemic
(eGHI), Hyperglycemic-euinsulinemic (HGeI). Control rats
were infused with 0,9% NaCl. In HGHI and HGeI rats
plasma glucose levels were maintained at 20-22 mmol/l. In
eGHI rats, plasma glucose was not different from that of
controls, whereas plasma insulin was much higher than
in controls. In HGHI rats, IRS-2 mRNA expression, total
protein and phosphorylated protein amounts were increased
compared to controls. In HGeI rats, only IRS-2
mRNA expression was increased. No change was observed
in eGHI rats whatever the parameter considered. In all
groups, mRNA concentration of IRS-1 was similar to that
of controls. The quantity of total and phosphorylated IRS-
1 protein was dramatically increased in HGHI rats and
to a lesser extent in eGHI rats. Neither mRNA nor IRS-1
protein expression were modified in HGeI rats. The data
suggest that glucose and insulin play at once a specific
and a complementary role in islet IRSs signaling. Especially,
glucose stimulates IRS-2 mRNA expression whatever
the insulin status and independently of the secretory
process. The differential regulation of IRS-1 and
IRS-2 expressions is in agreement with their supposed different involvement in the control of β-cell growth and
function. 相似文献
67.
68.
Translation of the stationary phase sigma factor RpoS is stimulated by at least two small RNAs, DsrA and RprA. DsrA disrupts an inhibitory secondary structure in the rpoS leader mRNA by pairing with the upstream RNA. Mutations in rprA and compensating mutations in the rpoS leader demonstrate that RprA interacts with the same region of the RpoS leader as DsrA. This is the first example of two different small RNAs regulating a common target. Regulation of these RNAs differs. DsrA synthesis is increased at low temperature. We find that RprA synthesis is regulated by the RcsC/RcsB phosphorelay system, previously found to regulate capsule synthesis and promoters of ftsZ and osmC. An rcsB null mutation abolishes the basal level, whereas mutations in rcsC that activate capsule synthesis also activate expression of the rprA promoter. An essential site with similarity to other RcsB-regulated promoters was defined in the rprA promoter. Activation of the RcsC/RcsB system leads to increased RpoS synthesis, in an RprA-dependent fashion. This work suggests a new signal for RpoS translation and extends the global regulation effected by the RcsC/RcsB system to coregulation of RpoS with capsule and FtsZ. 相似文献
69.
Development of two major resources for pea genomics: the GenoPea 13.2K SNP Array and a high‐density,high‐resolution consensus genetic map 下载免费PDF全文
Nadim Tayeh Christelle Aluome Matthieu Falque Françoise Jacquin Anthony Klein Aurélie Chauveau Aurélie Bérard Hervé Houtin Céline Rond Jonathan Kreplak Karen Boucherot Chantal Martin Alain Baranger Marie‐Laure Pilet‐Nayel Thomas D. Warkentin Dominique Brunel Pascal Marget Marie‐Christine Le Paslier Grégoire Aubert Judith Burstin 《The Plant journal : for cell and molecular biology》2015,84(6):1257-1273
70.
The soybean cyst nematode (SCN; Heterodera glycines) is a devastating obligate parasite of Glycine max (soybean) causing one billion dollars in losses to the US economy per year and over ten billion dollars in losses worldwide. While much is understood about the pathology of H. glycines, its genome sequence is not well characterized or fully sequenced. We sought to create bioinformatic tools to mine the H. glycines nucleotide database. One way is to use a comparative genomics approach by anchoring our analysis with an organism, like the free-living nematode Caenorhabditis elegans. Unlike H. glycines, the C. elegans genome is fully sequenced and is well characterized with a number of lethal genes identified through experimental methods. We compared an EST database of H. glycines with the C. elegans genome. Our goal was identifying genes that may be essential for H. glycines survival and would serve as an automated pipeline for RNAi studies to both study and control H. glycines. Our analysis yielded a total of nearly 8334 conserved genes between H. glycines and C. elegans. Of these, 1508 have lethal phenotypes/phenocopies in C. elegans. RNAi of a conserved ribosomal gene from H. glycines (Hg-rps-23) yielded dead and dying worms as shown by positive Sytox fluorescence. Endogenous Hg-rps-23 exhibited typical RNA silencing as shown by RT-PCR. However, an unrelated gene Hg-unc-87 did not exhibit RNA silencing in the Hg-rps-23 dsRNA-treated worms, demonstrating the specificity of the silencing. 相似文献