Search results for "intermediate"
showing 10 items of 440 documents
Electron Microscopic Contrast of the Cytoskeleton and Junctional Complexes of Intestinal Epithelial Cells by Ethanolic Phosphotungstic Acid
2000
After glutaraldehyde fixation and treatment with ethanolic phosphotungstic acid (E-PTA) before plastic embedding, sections of rat large intestine showed a characteristic electron contrasting pattern in epithelial cells. The axis of microvilli, terminal web, a thin band below the luminal plasma membrane, centrioles and junctional complexes (tight junctions, adherens junctions, and desmosomes) appeared highly contrasted. In addition to protein components of microfilaments and intermediate filaments, proteins from the junctional complexes could also be implicated in the contrasting reaction with E-PTA. Mitochondrial membranes, chromatin masses, and nucleoli of enterocytes showed considerable e…
Precision electroweak measurements on the Z resonance
2005
We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, $\MZ$ and $\GZ$, and its couplings to fermions, for example the $\rho$ parameter and the effective electroweak mixing angle, are precisely measured. The number of light neutrino species is determined to be 2.9840…
Electroweak measurements in electron-positron collisions at W-boson-pair energies at LEP
2013
The ALEPH, DELPHI, L3, OPAL collaborations and LEP Electroweak Working Group.-- arXiv:1302.3415
Life-history trade-offs in a generalist digenean from cetaceans: the role of host specificity and environmental factors
2015
Background Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures could shape reproductive traits of a putative generalist parasite in the oceanic realm. Methods The LSU rDNA, ITS2 and the mt-COI of individuals of the digenean Pholeter gastrophilus (Kossack, 1910) Odhner, 1914 (Heterophyidae Leiper, 1909) from oceanic striped dolphins, Stenella coeruleoalba Meyen, and coastal bottlenose dolphins, Tursiops truncatus Mo…
Induction of rapid and reversible cytokeratin filament network remodeling by inhibition of tyrosine phosphatases
2002
The cytokeratin filament network is intrinsically dynamic, continuously exchanging subunits over its entire surface, while conferring structural stability on epithelial cells. However, it is not known how cytokeratin filaments are remodeled in situations where the network is temporarily and spatially restricted. Using the tyrosine phosphatase inhibitor orthovanadate we observed rapid and reversible restructuring in living cells, which may provide the basis for such dynamics. By examining cells stably expressing fluorescent cytokeratin chimeras, we found that cytokeratin filaments were broken down and then formed into granular aggregates within a few minutes of orthovanadate addition. After …
A model for the γN → ππN reaction
1996
We have studied the γN → ππN reaction using a model wich includes N, Δ(1232), N*(1440) and N*(1520) intermediate baryonic states and the ρ-meson as a intermediate ππ resonance. The model reproduces fairly well experimental cross sections below Eγ=800 MeV and invariant-mass distributions even at higher energies. One of the interesting findings of study is what the γN → N*(1520) → Δπ process is very important and interferes strongly with the dominant Δ-Kroll-Ruderman term to produce the experimental peak of the kross section. Oset Baguena, Eulogio, Eulogio.Oset@ific.uv.es
Light-induced resistance of the keratin network to the filament-disrupting tyrosine phosphatase inhibitor orthovanadate.
2003
Epidermal keratinocytes respond to low-dose light irradiation by inducing signaling cascades that lead to long-term effects on gene transcription thereby protecting cells against damage. In contrast, little is known about immediate light-induced alterations of structural proteins. We have made the intriguing observation that light produces fundamental changes in the properties of the keratin filament system of cultured epidermoid A-431 cells. A short light exposure (1–10 min) causes the keratin cytoskeleton to become immediately resistant to the tyrosine phosphatase inhibitor orthovanadate, which otherwise disrupts the keratin filament network completely in just a few minutes. This protecti…
Effect of Short-Term Temperature Change on Cercarial Release by Rhipidocotyle fennica (Trematoda, Bucephalidae) from the Freshwater Bivalve Host, Ano…
2015
Cercarial release from the first intermediate host is an important stage in the transmission of trematode parasites. Besides long-term (seasonal) temperature fluctuations, short-term temperature changes can also influence cercarial emergence. We tested the response of the bucephalid trematode, Rhipidocotyle fennica (R. fennica), acclimatized to 17 °C, to an abrupt temperature change. As the natural cercarial shedding by this parasite takes place annually during the warmest season, we expected a positive effect of temperature increase. Monitoring during one hour after the transfer from 17 °C to 20 °C revealed a significant increase in R. fennica cercarial release compared to the preceding on…
Enzymatically modified nonoxidized low-density lipoprotein induces interleukin-8 in human endothelial cells: role of free fatty acids.
2002
Background— Treatment of low-density lipoprotein (LDL) with a protease and cholesterolesterase transforms the lipoprotein to an entity that resembles lipoprotein particles in atherosclerotic lesions, which have a high content of free cholesterol, reflecting extensive de-esterification in the intima. Because de-esterification would occur beneath the endothelium, we examined the effects of enzymatically modified LDL (E-LDL) on cultured endothelial cells. Methods and Results— Incubation of endothelial cells with E-LDL provoked selective accumulation of interleukin (IL)-8 mRNA and production of the cytokine. Chemical analyses and depletion experiments indicated that the effect was caused by th…
The Asian Taenia and the possibility of cysticercosis
2000
In certain Asian countries, a third form of human Taenia, also known as the Asian Taenia, has been discovered. This Asian Taenia seems to be an intermediate between Taenia solium and T. saginata since in morphological terms it is similar to T. saginata, yet biologically, as it uses the same intermediate host (pigs), it is more akin to T. solium. Taenia solium causes human cysticercosis, while T. saginata does not. It is not known whether the Asian taeniid is able to develop to the larval stage in humans or not. The arguments proposed by those authors who consider it unlikely that the Asian Taenia causes human cysticercosis are: (a) its molecular similarities with T. saginata; (b) the absenc…