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排序方式: 共有212条查询结果,搜索用时 31 毫秒
1.
2.
Sílvia Bronsoms Josep Villanueva Francesc Canals Enrique Querol Francesc X Aviles 《European journal of biochemistry》2003,270(17):3641-3650
Protein folding can be modulated in vivo by many factors. While chaperones act as folding catalysts and show broad substrate specificity, some pro-peptides specifically facilitate the folding of the mature protein to which they are bound. Potato carboxypeptidase inhibitor (PCI), a 39-residue protein carboxypeptidase inhibitor, is synthesized in vivo as a precursor protein that includes a 27-residue N-terminal and a seven-residue C-terminal pro-regions. In this work the disulfide-coupled folding of mature PCI in vitro has been compared with that of the same protein extended with either the N-terminal pro-sequence (ProNtPCI) or both N- and C-terminal pro-sequences (ProPCI), and also with the N-terminal pro-sequence in trans (ProNt + PCI). No significant differences can be observed in the folding kinetics or efficiencies of all these molecules. In addition, in vivo folding studies in Escherichia coli have been performed using wild-type PCI and three PCI mutant forms with and without the N-terminal pro-sequence, the mutations had been previously reported to affect folding of the PCI mature form. The extent to which the 'native-like' form was secreted to the media by each construction was not affected by the presence of the N-terminal pro-sequence. These results indicate that PCI does not depend on the N-terminal pro-sequence for its folding in both, in vitro and in vivo in E. coli. However, structural analysis by spectroscopy, hydrogen exchange and limited proteolysis by mass spectrometry, indicate the capability of such N-terminal pro-sequence to fold within the precursor form. 相似文献
3.
- 1. In the altricial rodent, Phyllotis darwini, we found higher body temperatures and faster developmental rates of the thermoregulatory capacity in neonates born from cold- than warm-acclimated mothers.
- 2. This difference could be explained by maternal effects on the litter, such as high levels of catecholamines and thyroxin levels, high concentration of the uncoupled protein and larger quantity of brown adipose tissue as a consequence of cold acclimation.
- 3. The exposition of mothers and the maintenance of cold condition during the early development might be responsible of the high metabolism and better thermoregulatory capacity of newborns.
Keywords: Phenotypic plasticity; Thermoregulation; Metabolism; Altricial rodents 相似文献
4.
Llorenç Milà i Canals Christian Bauer Jochen Depestele Alain Dubreuil Ruth Freiermuth Knuchel Gérard Gaillard Ottar Michelsen Ruedi Müller-Wenk Bernt Rydgren 《The International Journal of Life Cycle Assessment》2007,12(1):5-15
Background, Aim and Scope
Land use by agriculture, forestry, mining, house-building or industry leads to substantial impacts, particularly on biodiversity
and on soil quality as a supplier of life support functions. Unfortunately there is no widely accepted assessment method so
far for land use impacts. This paper presents an attempt, within the UNEP-SETAC Life Cycle Initiative, to provide a framework
for the Life Cycle Impact Assessment (LCIA) of land use.
Materials and Methods:
This framework builds from previous documents, particularly the SETAC book on LCIA (Lindeijer et al. 2002), developing essential
issues such as the reference for occupation impacts; the impact pathways to be included in the analysis; the units of measure
in the impact mechanism (land use interventions to impacts); the ways to deal with impacts in the future; and bio-geographical
differentiation.
Results:
The paper describes the selected impact pathways, linking the land use elementary flows (occupation; transformation) and parameters
(intensity) registered in the inventory (LCI) to the midpoint impact indicators and to the relevant damage categories (natural
environment and natural resources). An impact occurs when the land properties are modified (transformation) and also when
the current man-made properties are maintained (occupation).
Discussion:
The size of impact is the difference between the effect on land quality from the studied case of land use and a suitable reference
land use on the same area (dynamic reference situation). The impact depends not only on the type of land use (including coverage
and intensity) but is also heavily influenced by the bio-geographical conditions of the area. The time lag between the land
use intervention and the impact may be large; thus land use impacts should be calculated over a reasonable time period after
the actual land use finishes, at least until a new steady state in land quality is reached.
Conclusions:
Guidance is provided on the definition of the dynamic reference situation and on methods and time frame to assess the impacts
occurring after the actual land use. Including the occupation impacts acknowledges that humans are not the sole users of land.
Recommendations and Perspectives:
The main damages affected by land use that should be considered by any method to assess land use impacts in LCIA are: biodiversity
(existence value); biotic production potential (including soil fertility and use value of biodiversity); ecological soil quality
(including life support functions of soil other than biotic production potential). Bio-geographical differentiation is required
for land use impacts, because the same intervention may have different consequences depending on the sensitivity and inherent
land quality of the environment where it occurs. For the moment, an indication of how such task could be done and likely bio-geographical
parameters to be considered are suggested. The recommendation of indicators for the suggested impact categories is a matter
of future research. 相似文献
5.
Peña Claudia Civit Bárbara Gallego-Schmid Alejandro Druckman Angela Pires Armando Caldeira- Weidema Bo Mieras Eric Wang Feng Fava Jim Canals Llorenç Milà i Cordella Mauro Arbuckle Peter Valdivia Sonia Fallaha Sophie Motta Wladmir 《The International Journal of Life Cycle Assessment》2021,26(2):215-220
The International Journal of Life Cycle Assessment - The current global interest in circular economy (CE) opens an opportunity to make society’s consumption and production patterns more... 相似文献
6.
Loxoscelism is a health problem caused by the bite of spiders of the genus Loxosceles. In Chile all cases are attributable to Loxosceles laeta. It has been suggested that the spitting spider Scytodes globula may be a predator of L. laeta and control its population, which is only possible if they share the microhabitat. This study compared the thermal preferences and tolerances of the two species. Later, spiders acclimated to 15 °C and 25 °C were exposed to decreasing and increasing temperatures to determine the lower and upper critical temperatures. The preferred temperatures were lower during the morning, but there were no differences between the species. The thermal niche breadths were similar for the species, with a large overlap. Both species showed tolerance to extreme temperatures, but L. laeta showed greater tolerance to low temperatures. Both species showed acclimation of the lower critical temperatures to changes in acclimation temperatures. The similarity of preferred and tolerated temperatures was partly an expected fact, since the species share the same macrohabitat; these spider species are very common in domestic environments of central Chile. However, the results imply that their microhabitat choices are also very similar, indicating a high probability of meeting and predation, which could have important consequences in loxoscelism epidemiology. 相似文献
7.
Dane D. Jensen Cody B. Godfrey Christian Niklas Meritxell Canals Martina Kocan Daniel P. Poole Jane E. Murphy Farzad Alemi Graeme S. Cottrell Christoph Korbmacher Nevin A. Lambert Nigel W. Bunnett Carlos U. Corvera 《The Journal of biological chemistry》2013,288(32):22942-22960
TGR5 is a G protein-coupled receptor that mediates bile acid (BA) effects on energy balance, inflammation, digestion, and sensation. The mechanisms and spatiotemporal control of TGR5 signaling are poorly understood. We investigated TGR5 signaling and trafficking in transfected HEK293 cells and colonocytes (NCM460) that endogenously express TGR5. BAs (deoxycholic acid (DCA), taurolithocholic acid) and the selective agonists oleanolic acid and 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated cAMP formation but did not induce TGR5 endocytosis or recruitment of β-arrestins, as assessed by confocal microscopy. DCA, taurolithocholic acid, and oleanolic acid did not stimulate TGR5 association with β-arrestin 1/2 or G protein-coupled receptor kinase (GRK) 2/5/6, as determined by bioluminescence resonance energy transfer. 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated a low level of TGR5 interaction with β-arrestin 2 and GRK2. DCA induced cAMP formation at the plasma membrane and cytosol, as determined using exchange factor directly regulated by cAMP (Epac2)-based reporters, but cAMP signals did not desensitize. AG1478, an inhibitor of epidermal growth factor receptor tyrosine kinase, the metalloprotease inhibitor batimastat, and methyl-β-cyclodextrin and filipin, which block lipid raft formation, prevented DCA stimulation of ERK1/2. Bioluminescence resonance energy transfer analysis revealed TGR5 and EGFR interactions that were blocked by disruption of lipid rafts. DCA stimulated TGR5 redistribution to plasma membrane microdomains, as localized by immunogold electron microscopy. Thus, TGR5 does not interact with β-arrestins, desensitize, or traffic to endosomes. TGR5 signals from plasma membrane rafts that facilitate EGFR interaction and transactivation. An understanding of the spatiotemporal control of TGR5 signaling provides insights into the actions of BAs and therapeutic TGR5 agonists/antagonists. 相似文献
8.
Jordi Targarona Jeroen Warnaar Karin Petra Boessenkool Henk Brinkhuis Miquel Canals 《Grana》2013,52(2-3):170-178
The North Canary Basin (NW Africa) falls within a major eastern boundary upwelling system. This part of the coastal upwelling system is seasonal and is characterised by the development of large filaments migrating seawards. Hence, 16 samples from this location were selected to identify an “upwelling signal” in the composition of the dinoflagellate cyst assemblages. Samples closest to the most intense upwelling cells are dominated by L. machaerophorum and G. catenatum and Protoperidinium spp. These make up the “upwelling signal” characteristic for the system. Moreover, the “upwelling signal” can be advected offshore, with filaments that may extend as far as 300 km. Finally, the finding of cysts from G. catenatum, a toxic dinoflagellate, raises the need for a better understanding of the relationship between its presence and distribution in the region, and the coastal upwelling system. 相似文献
9.
Miguel Brandão Llorenç Milà i Canals 《The International Journal of Life Cycle Assessment》2013,18(6):1243-1252
Purpose
The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.Materials and methods
Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.Results and discussion
Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.Conclusions
The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation. 相似文献10.
John Faaborg Wayne J. Arendt Judith D. Toms Katie M. Dugger W. Andrew Cox Miguel Canals Mora 《Biodiversity and Conservation》2013,22(1):63-75
Despite concern expressed two decades ago, there has been little recent discussion about continuing declines of migrant bird populations. Monitoring efforts have been focused almost exclusively on the breeding grounds. We describe the long-term decline of a winter-resident bird population in Guánica Commonwealth Forest, Puerto Rico, one of the last remaining tracts of high-quality tropical dry forests in the Caribbean. The winter bird community has exhibited dramatic declines, with constant-effort mist netting now capturing about one-third as many birds as it did 20 years ago. Population estimates for the three most common species have declined dramatically, even though survival rates have remained constant, and other species are now virtually absent from a site where they once were fairly common. Although explanations for these declines are speculative, particularly because they involve multiple species, we argue that the strength and duration of these declines in well-preserved dry forest within a biosphere reserve should stimulate renewed discussion of migrant population trends and comparison with other recent monitoring activities. 相似文献