共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
Bartke A 《Cell metabolism》2007,6(3):153-154
Global reduction in insulin signaling has been linked to extended life span in a range of organisms. New work on mice with brain-specific or whole-body reductions in insulin receptor substrate 2 (IRS2) (Taguchi et al., 2007) points to a role for insulin/IGF-1 signaling in the central control of mammalian aging. 相似文献
5.
OBJECTIVE--To assess quality of storage of vaccines in the community. DESIGN--Questionnaire survey of general practices and child health clinics, and monitoring of storage temperatures of selected refrigerators. SETTING--Central Manchester and Bradford health districts. SUBJECTS--45 general practices and five child health clinics, of which 40 (80%) responded. Eight practices were selected for refrigeration monitoring. MAIN OUTCOME MEASURES--Adherence to Department of Health guidelines for vaccine storage, temperature range to which vaccines were exposed over two weeks. RESULTS--Of the 40 respondents, only 16 were aware of the appropriate storage conditions for the vaccines; eight had minimum and maximum thermometers but only one of these was monitored daily. In six of the eight practices selected for monitoring of refrigeration temperatures the vaccines were exposed to either subzero temperatures (three fridges) or temperatures up to 16 degrees C (three). Two of these were specialised drug storage refrigerators with an incorporated thermostat and external temperature gauges. CONCLUSION--Vaccines were exposed to temperatures that may reduce their potency. Safe storage of vaccines in the clinics cannot be ensured without adhering to the recommended guidelines. Provision of adequate equipment and training for staff in maintaining the "cold chain" and the use and care of equipment are important components of a successful immunisation programme. 相似文献
6.
Somatic mutations of mitochondrial DNA have been detected in various pathologies such as cancer, neurodegenerative diseases,
cardiac disorders and aging in general. Now it has been found that patients with rheumatoid arthritis also have a higher incidence
of mitochondrial mutations in synoviocytes and synovial tissue compared with patients with osteoarthritis. Furthermore, it
has been shown that these mutations possibly result in changed peptides that are presented by major histocompatibility complex
II and thus might be recognized as non-self by the immune system. Further studies will show whether these mutations are actually
able to trigger autoimmune inflammation in rheumatoid arthritis or whether they must be considered epiphenomena of cellular
damage in chronic inflammation. 相似文献
7.
8.
Allyn MacLean Stearman 《Human ecology: an interdisciplinary journal》1991,19(2):245-260
Questions concerning the availability of resources in tropical rain forests have given rise to the current debate centering on whether human subsistence based solely on foraging is possible in these biomes without agricultural subsidies. This paper takes the position that changing perspectives on ecological pattern and process in tropical forests and the significant variation among tropical forests on a worldwide as well as regional scale must be taken into consideration. Human disturbance is also proposed as a cause of dependence on agriculture by modern human foragers rather than as a necessary precondition for successful exploitation of the tropical forest. These issues are discussed against the background of a case study of the Yuquí, who, until very recently, were true foragers in the Bolivian Amazon. For the Yuquí, the sustainability of their subsistence system depended on a finegrained knowledge of their environment and the freedom of movement over a large territory to access resources within it. 相似文献
9.
Recently, alpha-L-arabinofuranosidases (EC3.2.1.55) have received increased attention primarily due to their role in the degradation of lignocelluloses as well as their positive effect on the activity of other enzymes acting on lignocelluloses. As a result, these enzymes are used in many biotechnological applications including wine industry, clarification of fruit juices, digestion enhancement of animal feedstuffs and as a natural improver for bread. Moreover, these enzymes could be used to improve existing technologies and to develop new technologies. The production, mechanisms of action, classification, synergistic role, biochemical properties, substrate specificities, molecular biology and biotechnological applications of these enzymes have been reviewed in this article. 相似文献
10.
Macroautophagy ("autophagy") is regulated by the same insulin-amino acid-mTOR signaling pathway that controls protein synthesis. Although the literature does not so far include any direct studies confirming this, we expect autophagy to increase during insulin resistance. We discuss the possibility that this may be a useful mechanism for eliminating damaged mitochondria and other cell structures to prevent cell death. 相似文献
11.
The Holliday junction is a key recombination intermediate whose resolution generates crossovers. Interplay between recombination, repair and replication has moved the Holliday junction to the center stage of nuclear DNA metabolism. Holliday junction resolvases in the eukaryotic nucleus have long eluded identification. The endonucleases Mus81/Mms4-Eme1 and XPF-MEI-9/MUS312 are structurally related to the archaeal resolvase Hjc and were found to be involved in crossover formation in budding yeast and flies, respectively. Although these endonucleases might represent one class of eukaryotic resolvases, their substrate preference opens up the possibility that junctions other than classical Holliday junctions might contribute to crossovers. Holliday junction resolution to non-crossover products can also be achieved topologically, for example, by the action of RecQ-like DNA helicases combined with topoisomerase III. 相似文献
12.
M H Johnson 《Current biology : CB》2001,11(7):R281-R284
An enduring but erroneous belief is that the post-fertilisation period is irrelevant for axis development in mammals. Two recent studies further undermine this belief. Is information for axial developmental encoded in the egg cortex? 相似文献
13.
We hypothesize that shifts in the annual pattern of the environmental parameters may affect the phenology of the zooplankton especially in temperate and polar areas. Five species (cold-water: Calanus glacialis, warm-water: Centropages hamatus, Temora longicornis, Acartia longiremis, and Evadne nordmanni) were tested with regard to the annual pattern of the water temperature using the dataset of 50-year-long monitoring in the White Sea (1961–2010). The hydrological summer duration increased by 20 days during the last 50 years, as it has been tracked by an earlier warming up of 0–10-m water layer in spring. Calanus glacialis responded to these changes by the appearance of CI copepodites earlier in the season. We suggest that the earlier start and longer period of ice melt may cause a longer phytoplankton bloom and thus may promote better trophic conditions during the period of Calanus reproduction and its early development. In contrast to cold-water C. glacialis, the phenology and abundance of warm-water copepods have not changed significantly. Both the timings of autumn cooling and average summer temperature remained relatively stable since the beginning of observations resulting in steady conditions during the reproductive period of warm-water species. Prolongation of summer had no effect on their reproduction. 相似文献
14.
15.
Olivier Duriez Jean-Marie Sachet Emmanuel Ménoni Nathalie Pidancier Christian Miquel Pierre Taberlet 《Conservation Genetics》2007,8(3):513-526
The Western capercaillie (Tetrao urogallus) is a keystone species of Palearctic boreal and altitude coniferous forests. With the increase of mountain leisure activities
and habitat loss, populations are declining in most mountain ranges in Western Europe. Recent work has shown that the populations
from the Pyrenees and Cantabrian Mountains survived a severe bottleneck during the 19th century, and are still considered
as threatened due to habitat fragmentation and isolation with other populations. We present an extensive phylogeographic study
based on mitochondrial DNA sequence (control region) extracted non-invasively from faeces collected throughout the species
range (from western European mountains to central and eastern Europe, Fenno-Scandia, Russia and Siberia). We also compared
our results with DNA sequences of closely related black-billed capercaillie (T. parvirostris). We found that populations from Pyrenees and Cantabrians are closely related but are different from all other capercaillie
populations that form a homogenous clade. Therefore, we consider that these South-Western populations should be considered
as forming an Evolutionary Significant Unit that needs an appropriate management at a local scale. We also discuss the possible
locations of glacial refugia and subsequent colonisation routes in Eurasia, with a Western “aquitanus” lineage from Iberia and Balkans, and an Eastern “urogallus” lineage from Southern Asia. This work might have important implication for capercaillie conservation strategies to define
important areas for conservation, and to prevent possible exchange or introductions of individuals originated from other lineages.
Electronic Supplementary Material The online version
of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
16.
17.
Christopher G. Elliott Shawna S. Kim Douglas W. Hamilton 《Cell Adhesion & Migration》2012,6(4):319-326
In the past year, three papers have been published exploring the role of the matricellular protein periostin in excisional skin repair. These papers all show a delay in wound closure and the kinetics of this delay are strikingly similar across the three reports. The similarities between these papers end, however, when each investigates the mechanism through which periostin influences skin repair. Three proposed mechanisms have been identified: (1) myofibroblast differentiation, (2) keratinocyte proliferation and (3) fibroblast proliferation and migration. The aim of this commentary is to compare and contrast the three studies performed to date in an attempt to decipher the role of periostin in the repair of full-thickness skin wounds. 相似文献
18.
《Ethnos》2012,77(2):177-202
Drawing on first-hand ethnographical data from the Xang"ô, an Afro-Brazilian Cult in Recife (Brazil), I defend that learning possession means in the first place to learn to identify and react to specific emotional states in accordance with cultural representations and expectations. This emotional learning would take place through two potential processes during ritual activity. On the one hand a powerful coupling process linking “uncanny” body arousals to mythological imagination captured by the highly evocative content of songs, invocations, objects and substances during ritual activity. Ritual features such as archetypality, rigidity, regularity, redundancy and spatial and temporal delimitation are propitious for eliciting and “boosting” this coupling process. On the other hand, a social referencing process through which emotional and behavioral reactions towards possessed persons act for novices as reliable indicators of how to recognize, interpret and regulate their own emotional states associated with possession. With growing familiarity with possession's conceptual and experiential background, their emotional reactions might evolve from largely undifferentiated arousal states to “orixa´-specific” somatic signature and novices might become more active towards their own possession. They also demonstrate an increasing sensitivity to isolated emotional elicitors of possession as well as a better control over their emotional reaction. 相似文献
19.
Freya Harrison 《BioEssays : news and reviews in molecular, cellular and developmental biology》2013,35(2):108-112
Individual bacterial cells can communicate via quorum sensing, cooperate to harvest nutrients from their environment, form multicellular biofilms, compete over resources and even kill one another. When the environment that bacteria inhabit is an animal host, these social behaviours mediate virulence. Over the last decade, much attention has focussed on the ecology, evolution and pathology of bacterial cooperation, and the possibility that it could be exploited or destabilised to treat infections. But how far can we really extrapolate from theoretical predictions and laboratory experiments to make inferences about ‘cooperative’ behaviours in hosts and reservoirs? To determine the likely importance and evolution of cooperation ‘in the wild’, several questions must be addressed. A recent paper that reports the dynamics of bacterial cooperation and virulence in a field experiment provides an excellent nucleus for bringing together key empirical and theoretical results which help us to frame – if not completely to answer – these questions. 相似文献
20.