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991.
Crone EE Menges ES Ellis MM Bell T Bierzychudek P Ehrlén J Kaye TN Knight TM Lesica P Morris WF Oostermeijer G Quintana-Ascencio PF Stanley A Ticktin T Valverde T Williams JL 《Ecology letters》2011,14(1):1-8
Matrix projection models are among the most widely used tools in plant ecology. However, the way in which plant ecologists use and interpret these models differs from the way in which they are presented in the broader academic literature. In contrast to calls from earlier reviews, most studies of plant populations are based on < 5 matrices and present simple metrics such as deterministic population growth rates. However, plant ecologists also cautioned against literal interpretation of model predictions. Although academic studies have emphasized testing quantitative model predictions, such forecasts are not the way in which plant ecologists find matrix models to be most useful. Improving forecasting ability would necessitate increased model complexity and longer studies. Therefore, in addition to longer term studies with better links to environmental drivers, priorities for research include critically evaluating relative/comparative uses of matrix models and asking how we can use many short-term studies to understand long-term population dynamics. 相似文献
992.
993.
Akhtar A Fuchs E Mitchison T Shaw RJ St Johnston D Strasser A Taylor S Walczak C Zerial M 《Nature reviews. Molecular cell biology》2011,12(10):669-674
Nature Reviews Molecular Cell Biology celebrated its 10-year anniversary during this past year with a series of specially commissioned articles. To complement this, here we have asked researchers from across the field for their insights into how molecular cell biology research has evolved during this past decade, the key concepts that have emerged and the most promising interfaces that have developed. Their comments highlight the broad impact that particular advances have had, some of the basic understanding that we still require, and the collaborative approaches that will be essential for driving the field forward. 相似文献
994.
Ants are the dominant soil faunal group in many if not most terrestrial ecosystems, and play a key role in soil structure
and function. This study documents the impacts of invasion by the exotic cat’s claw creeper vine, Macfadyena
unguis-cati (L.) Gentry (Bignoniaceae) on surface-situated (epigaeic) and subterranean (hypogaeic) ant communities in subtropical SE
Queensland Australia where it is a major environmental weed of riparian areas, rainforest communities and remnant natural
vegetation, smothering standing vegetation and causing canopy collapse. Soil ants were sampled in infested and uninfested
areas at eight sites spanning both riparian and non-riparian habitats in subtropical SE Queensland. Patterns of ant species
composition and functional grouping in response to patch invasion status, landscape type and habitat stratum were investigated
using ANOVA and non-metric multidimensional scaling ordination. The epigaeic and subterranean strata supported markedly different
ant assemblages, and ant communities also differed between riparian and non-riparian habitats. However, M. unguis-cati invasion had a surprisingly limited impact. There was a tendency for ant abundance and species richness to be lower in infested
patches, and overall species composition was different between infested and uninfested patches, but these differences were
relatively small, and did not occur consistently across sites. There were changes in functional group composition that conformed
to known functional group responses to environmental change, but these were similarly limited and inconsistent across sites.
Our study has shown that ant communities are surprisingly resilient to invasion by M. unguis-cati, and serves as a warning against making assumptions about invasion impacts based on visual appearances. 相似文献
995.
Amanda Gatesman Ammer Karen E. Hayes Karen H. Martin Lingqing Zhang George A. Spirou Scott A. Weed 《Journal of visualized experiments : JoVE》2011,(53)
Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient management strategies. Orthotopic mouse models of oral cancer have been developed to facilitate the study of factors that impact invasion and serve as model system for evaluating anti-tumor therapeutics. In these systems, visualization of disseminated tumor cells within oral cavity tissues has typically been conducted by either conventional histology or with in vivo bioluminescent methods. A primary drawback of these techniques is the inherent inability to accurately visualize and quantify early tumor cell invasion arising from the primary site in three dimensions. Here we describe a protocol that combines an established model for squamous cell carcinoma of the tongue (SCOT) with two-photon imaging to allow multi-vectorial visualization of lingual tumor spread. The OSC-19 head and neck tumor cell line was stably engineered to express the F-actin binding peptide LifeAct fused to the mCherry fluorescent protein (LifeAct-mCherry). Fox1nu/nu mice injected with these cells reliably form tumors that allow the tongue to be visualized by ex-vivo application of two-photon microscopy. This technique allows for the orthotopic visualization of the tumor mass and locally invading cells in excised tongues without disruption of the regional tumor microenvironment. In addition, this system allows for the quantification of tumor cell invasion by calculating distances that invaded cells move from the primary tumor site. Overall this procedure provides an enhanced model system for analyzing factors that contribute to SCOT invasion and therapeutic treatments tailored to prevent local invasion and distant metastatic spread. This method also has the potential to be ultimately combined with other imaging modalities in an in vivo setting. 相似文献
996.
Grantham HS Game ET Lombard AT Hobday AJ Richardson AJ Beckley LE Pressey RL Huggett JA Coetzee JC van der Lingen CD Petersen SL Merkle D Possingham HP 《PloS one》2011,6(2):e16552
Pelagic ecosystems support a significant and vital component of the ocean's productivity and biodiversity. They are also heavily exploited and, as a result, are the focus of numerous spatial planning initiatives. Over the past decade, there has been increasing enthusiasm for protected areas as a tool for pelagic conservation, however, few have been implemented. Here we demonstrate an approach to plan protected areas that address the physical and biological dynamics typical of the pelagic realm. Specifically, we provide an example of an approach to planning protected areas that integrates pelagic and benthic conservation in the southern Benguela and Agulhas Bank ecosystems off South Africa. Our aim was to represent species of importance to fisheries and species of conservation concern within protected areas. In addition to representation, we ensured that protected areas were designed to consider pelagic dynamics, characterized from time-series data on key oceanographic processes, together with data on the abundance of small pelagic fishes. We found that, to have the highest likelihood of reaching conservation targets, protected area selection should be based on time-specific data rather than data averaged across time. More generally, we argue that innovative methods are needed to conserve ephemeral and dynamic pelagic biodiversity. 相似文献
997.
A tethered bilayer assembled on top of immobilized calmodulin to mimic cellular compartmentalization
Background
Biomimetic membrane models tethered on solid supports are important tools for membrane protein biochemistry and biotechnology. The supported membrane systems described up to now are composed of a lipid bilayer tethered or not to a surface separating two compartments: a ”trans” side, one to a few nanometer thick, located between the supporting surface and the membrane; and a “cis” side, above the synthetic membrane, exposed to the bulk medium. We describe here a novel biomimetic design composed of a tethered bilayer membrane that is assembled over a surface derivatized with a specific intracellular protein marker. This multilayered biomimetic assembly exhibits the fundamental characteristics of an authentic biological membrane in creating a continuous yet fluid phospholipidic barrier between two distinct compartments: a “cis” side corresponding to the extracellular milieu and a “trans” side marked by a key cytosolic signaling protein, calmodulin.Methodology/Principal Findings
We established and validated the experimental conditions to construct a multilayered structure consisting in a planar tethered bilayer assembled over a surface derivatized with calmodulin. We demonstrated the following: (i) the grafted calmodulin molecules (in trans side) were fully functional in binding and activating a calmodulin-dependent enzyme, the adenylate cyclase from Bordetella pertussis; and (ii) the assembled bilayer formed a continuous, protein-impermeable boundary that fully separated the underlying calmodulin (trans side) from the above medium (cis side).Conclusions
The simplicity and robustness of the tethered bilayer structure described here should facilitate the elaboration of biomimetic membrane models incorporating membrane embedded proteins and key cytoplasmic constituents. Such biomimetic structures will also be an attractive tool to study translocation across biological membranes of proteins or other macromolecules. 相似文献998.
Konyukh M Delorme R Chaste P Leblond C Lemière N Nygren G Anckarsäter H Rastam M Ståhlberg O Amsellem F Gillberg IC Mouren-Simeoni MC Herbrecht E Fauchereau F Toro R Gillberg C Leboyer M Bourgeron T 《PloS one》2011,6(3):e17289
Background
Autism spectrum disorders (ASD) are a group of severe childhood neurodevelopmental disorders with still unknown etiology. One of the most frequently reported associations is the presence of recurrent de novo or inherited microdeletions and microduplications on chromosome 16p11.2. The analysis of rare variations of 8 candidate genes among the 27 genes located in this region suggested SEZ6L2 as a compelling candidate.Methodology/Principal Findings
We further explored the role of SEZ6L2 variations by screening its coding part in a group of 452 individuals, including 170 patients with ASD and 282 individuals from different ethnic backgrounds of the Human Genome Diversity Panel (HGDP), complementing the previously reported screening. We detected 7 previously unidentified non-synonymous variations of SEZ6L2 in ASD patients. We also identified 6 non-synonymous variations present only in HGDP. When we merged our results with the previously published, no enrichment of non-synonymous variation in SEZ6L2 was observed in the ASD group compared with controls.Conclusions/Significance
Our results provide an extensive ascertainment of the genetic variability of SEZ6L2 in human populations and do not support a major role for SEZ6L2 sequence variations in the susceptibility to ASD. 相似文献999.
Background
Successful observation of behaviour depends upon knowing both which behaviours to look for and focusing on the appropriate areas of the body to observe them. Behaviour based scoring systems have become increasingly widely used to assess animal pain and distress. Although studies are available demonstrating which behaviours need to be observed, there has been little attempt to assess how effectively observers apply such information when viewing an animal''s behaviour.Methodology/Principal Findings
This study used historical video recordings of New Zealand white rabbits (Oryctolagus cuniculi) considered to be experiencing varying degrees of post-operative pain to assess the pattern of observation and the ability to assess pain exhibited by both experienced and inexperienced human participants (n = 151). Eye tracking equipment was used to identify how quickly, how frequently, for how long different areas of the rabbit''s body were attended to by the participants. Simple visual analgoue scoring was used to assess the pain experienced in each sequence. The results demonstrate that irrespective of their experience or gender, observers focus first, more frequently and for longer on the face, compared to the abdomen, ears, back and hindquarters of the rabbit and that participants were poor at identifying rabbits in pain. Observing the back and hindquarters was correlated with ‘correct’ assessments and observing the face was correlated with ‘incorrect’ assessments.Conclusions
In conclusion, irrespective of experience and gender, observers focused on the face when using behaviour to assess pain and were unable to effectively identify rabbits in pain. Focusing on the face is unlikely to be effective when using behavioural indicators of pain since they involve other body areas. Alternatively, if animals exhibit pain-related facial expressions, then it could improve our ability to assess pain. In addition, these results have potential implications for the use of behaviour to assess how rabbits and potentially other species feel. 相似文献1000.