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91.
Howard CH Yim Die Wang Liang Yu Christine L White Pieter W Faber Bryan RG Williams Anthony J Sadler 《Cell research》2016,26(3):367-379
The protein kinase R (PKR) functions in the antiviral response by controlling protein translation and inflammatory cell signaling pathways. We generated a transgenic, knock-in mouse in which the endogenous PKR is expressed with a point mutation that ablates its kinase activity. This novel animal allows us to probe the kinase-dependent and -independent functions of PKR. We used this animal together with a previously generated transgenic mouse that is ablated for PKR expression to determine the role of PKR in regulating the activity of the cryopyrin inflammasome. Our data demonstrate that, in contradiction to earlier reports, PKR represses cryopyrin inflammasome activity. We demonstrate that this control is mediated through the established function of PKR to inhibit protein translation of constituents of the inflammasome to prevent initial priming during innate immune signaling. These findings identify an important role for PKR to dampen inflammation during the innate immune response and caution against the previously proposed therapeutic strategy to inhibit PKR to treat inflammation. 相似文献
92.
The relationship between Chironomus plumosus burrows and the spatial distribution of pore-water phosphate, iron and ammonium in lake sediments 总被引:1,自引:0,他引:1
1. To study the influence of chironomids on the distribution of pore‐water concentrations of phosphate, iron and ammonium, we conducted a laboratory experiment using mesocosms equipped with two‐dimensional pore‐water samplers, filled with lake sediment and populated with different densities of Chironomus plumosus. 2. Specially designed mesocosms were used in the study. A 6‐mm deep space between the front plate and the pore‐water sampler at the back plate was just thick enough to allow the chironomids to live undisturbed, yet thin enough to force all the burrows into a two‐dimensional plane. 3. The courses of the burrows were observed during the experiment as oxidised zones surrounding them, as well as being identified with an X‐ray image taken at the end of the experiment. 4. We investigated the relationship between C. plumosus burrows and spatial patterns of pore‐water composition. Concentrations of the three ions were significantly less around ventilated burrows (54% to 24%), as bioirrigation caused a convective exchange of pore‐water enriched with dissolved species compared with the overlying water, and also because oxygen imported into the sediment resulting in nitrification of ammonium, oxidation of iron(II) and a co‐precipitation of phosphate with Fe(III) oxyhydroxides. 5. In mesocosms with chironomids, new (redox) interfaces occurred with diffusive pore‐water gradients perpendicular to the course of burrows and the site of major phosphate, ammonium and iron(II) release shifted from the sediment surface to the burrow walls. 相似文献
93.
JÖRG MALETZ 《Palaeontology》2005,48(4):763-780
Abstract: Early Middle Ordovician graptolites from the Albjära and Lovisefred drill cores (Scania, southern Sweden) can be differentiated into the Isograptus victoriae , Isograptus sp. nov. 2 and Maeandrograptus schmalenseei , Arienigraptus dumosus type/ Pseudisograptus manubriatus biozones of Castlemainian and Yapeenian age and the Arienigraptus zhejiangensis and Undulograptus sinicus biozones of early Darriwilian age, replacing the old, long-ranging Didymograptus hirundo Biozone. Faunas from the drill cores include a number of species not previously recognized in Scandinavia. 相似文献
94.
Jenn M Croke Luke RG Pike Daniel J MacPhee 《Reproductive biology and endocrinology : RB&E》2007,5(1):22
Background
Myometrial growth and remodeling of the cytoskeleton and focal adhesions during late pregnancy may be critical aspects of myometrial activation and thus labour. Yet our understanding of these aspects is inhibited by the paucity of information concerning the components of focal adhesions in the myometrium. The focal adhesion protein hydrogen peroxide-inducible clone-5 (Hic-5) has recently been found in mononuclear smooth muscle but was not examined in the myometrium during pregnancy. Thus, the goal of this study was to characterize Hic-5 mRNA and protein expression in the rat myometrium during pregnancy and labour. 相似文献95.
96.
97.
Bjaelde RG Arnadottir SS Leipziger J Praetorius HA 《The Journal of membrane biology》2011,244(1):43-53
Translocation of vesicles within the cytoplasm is essential to normal cell function. The vesicles are typically transported
along the microtubules to their destination. The aim of this study was to characterize the vesicular movement in resting and
stimulated renal epithelial cells. MDCK cells loaded with either quinacrine or acridine orange, dyes taken up by acidic vesicles,
were observed at 37°C in semiopen perfusion chambers. Time-lapse series were analyzed by Imaris software. Our data revealed
vigorous movement of stained vesicles in resting MDCK cells. These movements seem to require intact microtubules because nocodazole
leads to a considerable reduction of the vesicular movements. Interestingly, we found that extracellular ATP caused the vesicular
movement to cease. This observation was obvious in time lapse. Similarly, other stimuli known to increase the intracellular
Ca2+ concentration ([Ca2+]i) in MDCK cells (increment in the fluid flow rate or arginine vasopressin) also reduced the vesicular movement. These findings
were quantified by analysis of single vesicular movement patterns. In this way, ATP was found to reduce the lateral displacement
of the total population of vesicles by 40%. Because all these perturbations increase [Ca2+]i, we speculated that this increase in [Ca2+]i was responsible for the vesicle arrest. Therefore, we tested the effect of the Ca2+ ionophore, ionomycin (1 μM), which in the presence of extracellular Ca2+ resulted in a considerable and sustained reduction of vesicular movement amounting to a 58% decrease in average lateral vesicular
displacement. Our data suggest that vesicles transported on microtubules are paused when subjected to high intracellular Ca2+ concentrations. This may provide an additional explanation for the cytotoxic effect of high [Ca2+]i. 相似文献
98.
Abstract: Several new taxa of snakeflies (Raphidioptera) are described from the Lower Cretaceous deposits of the Wealden, UK (Barremian), Montsec, Spain (Barremian) and the Crato Formation, Brazil (Aptian). Mesoraphidia ednae sp. nov. and M. hilli sp. nov. are described from the Wealden; Nanoraphidia lithographica sp. nov. and Iberoraphidia dividua gen. et sp. nov. are described from Montsec, and Baissoptera lisae sp. nov. is described from the Crato Formation. The geographical range of Nanoraphidia has potentially been extended. 相似文献
99.
Adjustment of vibratory signals to ambient temperature in a host-searching parasitoid 总被引:1,自引:1,他引:0
Abstract. Certain ichneumonid parasitoids (Hymenoptera) use self-produced vibrations transmitted on plant substrate, so-called vibrational sounding, to locate their immobile concealed pupal hosts. An ambient temperature dependency with higher frequencies and intensities at higher temperatures is postulated because signals are of myogenic origin. Here, temperature influence on vibratory signals is analysed in the temperate parasitoid Pimpla turionellae under different thermal conditions using plant-stem models to elicit host-searching behaviour. Signals are measured with laser Doppler vibrometry and analysed for time parameters and frequency components applying fast-Fourier transformations. The results reveal an unexpected effect of ambient temperature on signals produced by the female wasps. Although average values of time parameters (pulse trains, pulse train periods, inter pulse duration) are unchanged by ambient temperature, the frequency parameters show an inverse thermal effect. Within the temperature range tested (8–26 °C), decreasing temperature leads to significantly higher frequency and intensity of the self-produced vibrations in the temperate species. This inverse thermal effect may be explained by a temperature-coupled signal production in the frequency domain to compensate negative low-temperature effects on the mechanoreceptors by increased muscle activity. The option of heterothermy to produce signals reliably during vibrational sounding under low temperature is also discussed. 相似文献
100.