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951.
Roxane M Barthélémy Anne Chenuil Samuel Blanquart Jean-Paul Casanova Eric Faure 《BMC evolutionary biology》2007,7(1):146
Background
Chaetognaths, or arrow worms, are small marine, bilaterally symmetrical metazoans. The objective of this study was to analyse ribosomal protein (RP) coding sequences from a published collection of expressed sequence tags (ESTs) from a chaetognath (Spadella cephaloptera) and to use them in phylogenetic studies. 相似文献952.
At the beginning of the twentieth century, the biologist Joseph Grinnell made a distinction between science and sentiment for producing fact-based generalizations on how to conserve biodiversity. We are inspired by Grinnellian science, which successfully produced a century-long impact on studying and conserving biodiversity that runs orthogonal to some familiar philosophical distinctions such as fact versus value, emotion versus reason and basic versus applied science. According to Grinnell, unlike sentiment-based generalizations, a fact-based generalization traces its diverse commitments and thus becomes tractable for its audience. We argue that foregrounding tractability better explains Grinnell’s practice in the context of his time as well as in the context of current discourse among scientists over the political “biases” of biodiversity research and its problem of “reproducibility.” 相似文献
953.
954.
THE polysaccharides obtained from some basidiomycetes, Pleurotus ostreatus (Jacq. ex Fr.) Quel.1, Flammulina velutipes (Curt, ex Fr.) Sing.2, Lentinus edodes (Berk.) Sing.2–4, Polia cocos, Wolf (Bukuryo)5 and Schizophyllum commune Fr.7, strongly inhibit the growth of sarcoma 180 and their anti-tumour activity is host-mediated8,9. 相似文献
955.
Alexey V. Morozov Tatiana M. Astakhova David G. Garbuz George S. Krasnov Natalia V. Bobkova Olga G. Zatsepina Vadim L. Karpov Michail B. Evgen’ev 《Cell stress & chaperones》2017,22(5):687-697
The heat shock protein 70 (Hsp70, human HSPA1A) plays indispensable roles in cellular stress responses and protein quality control (PQC). In the framework of PQC, it cooperates with the ubiquitin-proteasome system (UPS) to clear damaged and dysfunctional proteins in the cell. Moreover, Hsp70 itself is rapidly degraded following the recovery from stress. It was demonstrated that its fast turnover is mediated via ubiquitination and subsequent degradation by the 26S proteasome. At the same time, the effect of Hsp70 on the functional state of proteasomes has been insufficiently investigated. Here, we characterized the direct effect of recombinant Hsp70 on the activity of 20S and 26S proteasomes and studied Hsp70 degradation by the 20S proteasome in vitro. We have shown that the activity of purified 20S proteasomes is decreased following incubation with recombinant human Hsp70. On the other hand, high concentrations of Hsp70 activated 26S proteasomes. Finally, we obtained evidence that in addition to previously reported ubiquitin-dependent degradation, Hsp70 could be cleaved independent of ubiquitination by the 20S proteasome. The results obtained reveal novel aspects of the interplay between Hsp70 and proteasomes. 相似文献
956.
Rendal Vázquez ME Díaz Román TM Rodríguez Cabarcos M Zavanella Botta C Domenech García N González Cuesta M Sánchez Dopico MJ Pértega Díaz S Andión Núñez C 《Cell and tissue banking》2008,9(2):101-107
To analyse the influence of cold ischemic time (CIT) (2–24 h) and of cryopreservation (liquid phase) on the viability of the
valvular fibroblasts and in the presence of apoptosis. Cardiac valves from 10 pigs were evaluated by anatomo-pathological
study of the wall, muscle and leaflet. At the same time, the presence of cellular death due to apoptosis was investigated
in two ways; directly on tissue by Apodetec system and by two-colour flow cytometry assay analyzing a suspension of fibroblast
from valve leaflets using Anexina V and propidium iodure (PI). We established three groups of samples to compare different
experimental conditions: 2 h of ischemia (group 1), 24 h of ischemia (group 2), and a programme of cryopreservation (−1°C/min)
after 2 h of ischemia, followed by storage in liquid nitrogen during a week and thawing was performed (group 3). The analysis
of viabilities showed slight differences between all three groups. The results indicated CIT of 24 h undergoing more structural
affectation than CIT of 2 h. Flow cytometry analysis did not show important differences between groups; however cryopreserved
samples (group 3) slightly less viability and a higher percentage of death by apoptosis than group 1 and 2 using flow cytometry.
Apoptosis was confirmed on tissue from all valves but mainly in samples of group 2 and group 3. In summary, the viability
of the valves in the case of ischemic times of 2 h, 24 h or after cryopreservation/thawing differs slightly. The death of
the cells is mainly mediated by necrosis and not by apoptosis. 相似文献
957.
Lorena Rela Sung Min Yang Lidia Szczupak 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(2):139-150
The NS neurons are nonspiking cells, present as pairs in each midbody ganglion of the leech nervous system, which display
a very extensive arborization. They were shown to regulate the coactivation of motoneurons. Here we have investigated the
electrophysiological properties of these neurons under the hypothesis that transmission along the extensive neurites requires
the aid of voltage-dependent conductances. The results indicate that NS neurons respond to electrical stimulation with a spike-like
event, which was not an all-or-none but rather a graded phenomenon that depended on the intensity and duration of the electrical
stimulus. The spike-like response was activated at a membrane potential of approximately −50 mV; its amplitude was a logarithmic
function of the extracellular Ca2+ concentration and was unaffected by a broad range of changes in the extracellular Na+ concentration; intracellular application of tetraethylammonium (TEA) caused a large increase in its amplitude and duration.
These data indicate that NS neurons bear voltage-dependent low-threshold Ca2+ and TEA-sensitive K+ conductances that could contribute to shaping synaptic signals, or transmission along the extensive neuritic tree. 相似文献
958.
959.
Linlin Wang Sujeethraj Koppolu Catherine Chappell Bernard J. Moncla Sharon L. Hillier Lara K. Mahal 《PloS one》2015,10(5)
The cervicovaginal fluid (CVF) coating the vaginal epithelium is an important immunological mediator, providing a barrier to infection. Glycosylation of CVF proteins, such as mucins, IgG and S-IgA, plays a critical role in their immunological functions. Although multiple factors, such as hormones and microflora, may influence glycosylation of the CVF, few studies have examined their impact on this important immunological fluid. Herein we analyzed the glycosylation of cervicovaginal lavage (CVL) samples collected from 165 women under different hormonal conditions including: (1) no contraceptive, post-menopausal, (2) no contraceptive, days 1-14 of the menstrual cycle, (3) no contraceptive, days 15-28 of the menstrual cycle, (4) combined-oral contraceptive pills for at least 6 months, (5) depo-medroxyprogesterone acetate (Depo-Provera) injections for at least 6 months, (6) levonorgestrel IUD for at least 1 month. Glycomic profiling was obtained using our lectin microarray system, a rapid method to analyze carbohydrate composition. Although some small effects were observed due to hormone levels, the major influence on the glycome was the presence of an altered bacterial cohort due to bacterial vaginosis (BV). Compared to normal women, samples from women with BV contained lower levels of sialic acid and high-mannose glycans in their CVL. The change in high mannose levels was unexpected and may be related to the increased risk of HIV-infection observed in women with BV, as high mannose receptors are a viral entry pathway. Changes in the glycome were also observed with hormonal contraceptive use, in a contraceptive-dependent manner. Overall, microflora had a greater impact on the glycome than hormonal levels, and both of these effects should be more closely examined in future studies given the importance of glycans in the innate immune system. 相似文献
960.
Thierry Rème Dirk Hose John De Vos Aurélien Vassal Pierre-Olivier Poulain Véronique Pantesco Hartmut Goldschmidt Bernard Klein 《BMC bioinformatics》2008,9(1):16