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941.
Leila M. Porter Sarah M. Sterr Paul A. Garber 《International journal of primatology》2007,28(5):1035-1058
We studied the diet, habitat use, and ranging behavior of 1 group of Callimico goeldii (callimicos) over 12 mo in northwestern Bolivia. The group’s diet was comprised of fungi (39%), fruits (31%), arthropods
(14%), exudates (14%), and other matter (2%). Callimicos concentrated their ranging activities in secondary forest (50%),
primary forest with dense understory (30%), and bamboo (17%) habitats. The group’s total home range was 114 ha; on average
they used 38.4 ha/ mo and had a day range of 925 m. Monthly average day ranges—but not monthly home ranges—increased as frugivory
declined, suggesting that subjects foraged on fungi and exudates by rechecking resources within a core area, making their
day ranges longer than during months when they concentrated on fruit resources. The callimicos formed polyspecific associations
with tamarins (Saguinus labiatus and S. fuscicollis) during 81% of observations. Day ranges increased in months with higher association rates which appears to result from the
callimicos using a broader set of habitats when with tamarins than when alone. The ranging pattern of callimicos appears to
be influenced primarily by 3 factors: their seasonal shift in diet requires that they forage in a variety of habitats across
the year; their depletion of resources causes them to shift their core area over time; and their lack of territorial behavior
eliminates the need to patrol boundaries as part of their daily movement. As a result, callimicos differ from many other callitrichids
in their low ratio of day range length to home range size. 相似文献
942.
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943.
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
944.
Rodrigo Grassi-Oliveira Hugo Cogo-Moreira Giovanni Abrah?o Salum Elisa Brietzke Thiago Wendt Viola Gisele Gus Manfro Christian Haag Kristensen Adriane Xavier Arteche 《PloS one》2014,9(1)
The Childhood Trauma Questionnaire (CTQ) is internationally accepted as a key tool for the assessment of childhood abuse and neglect experiences. However, there are relative few psychometric studies available and some authors have proposed two different factor solutions. We examined the dimensional structure and internal consistency of the Brazilian version of the CTQ. A total of 1,925 participants from eight different clinical and non-clinical samples including adolescents, adults and elders were considered in this study. First, we performed Confirmatory Factor Analysis to investigate the goodness of fit of the two proposed competitive factor structure models for the CTQ. We also investigated the internal consistency of all factors. Second, multi-group analyses were used to investigate measurement invariance and population heterogeneity across age groups and sex. Our findings revealed that the alternative factor structure as opposed to the original factor structure was the most appropriate model within adolescents and adults Brazilian samples. We provide further evidence for the validity and reliability of the CTQ within the Brazilian samples and report that the alternative model showed an improvement in fit indexes and may be a better alternative over the original model. 相似文献
945.
Barbara C. Klump Jessica E. M. van der Wal James J. H. St Clair Christian Rutz 《Proceedings. Biological sciences / The Royal Society》2015,282(1808)
Several animal species use tools for foraging, such as sticks to extract embedded arthropods and honey, or stones to crack open nuts and eggs. While providing access to nutritious foods, these behaviours may incur significant costs, such as the time and energy spent searching for, manufacturing and transporting tools. These costs can be reduced by re-using tools, keeping them safe when not needed. We experimentally investigated what New Caledonian crows do with their tools between successive prey extractions, and whether they express tool ‘safekeeping’ behaviours more often when the costs (foraging at height), or likelihood (handling of demanding prey), of tool loss are high. Birds generally took care of their tools (84% of 176 prey extractions, nine subjects), either trapping them underfoot (74%) or storing them in holes (26%)—behaviours we also observed in the wild (19 cases, four subjects). Moreover, tool-handling behaviour was context-dependent, with subjects: keeping their tools safe significantly more often when foraging at height; and storing tools significantly more often in holes when extracting more demanding prey (under these conditions, foot-trapping proved challenging). In arboreal environments, safekeeping can prevent costly tool losses, removing a potentially important constraint on the evolution of habitual and complex tool behaviour. 相似文献
946.
947.
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
948.
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
949.
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
950.
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